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  • 1. January 2014 KEY ADVANCES IN MEDICINE © 2014 Macmillan Publishers Limited. All rights reserved
  • 2. Key Advances in Medicine design:lauramarshall Nature Reviews Cardiology 1 ACUTE CORONARY SYNDROMES | Optimizing revascularization strategies in patients with ACS Gregg W. Stone 3 heart failure | Continue what we are doing to treat HF, but do it better Jay N. Cohn 4 venous thromboembolism | The advent of the novel oral anticoagulants Paolo Prandoni 6 dyslipidaemia | New statin guidelines and promising novel therapeutics Dimitri P. Mikhailidis and Vasilios G. Athyros 8 cardiovascular imaging | New era of evidence-based medicine with noninvasive imaging Puskar Pattanayak and David A. Bluemke Nature Reviews Clinical Oncology 11 lung cancer | Refining standard practice and admitting uncertainty Stephen V. Liu and Giuseppe Giaccone 13 breast cancer | Genomics, drug approval, and optimal treatment duration Adrian V. Lee and Nancy E. Davidson 15 liver cancer | Mutational landscape of HCC—the end of the beginning Augusto Villanueva and Josep M. Llovet 17 melanoma | Melanoma—the run of success continues Dirk Schadendorf and Axel Hauschild 19 cervical cancer | Screening comes of age and treatment progress continues Chris J. L. M. Meijer and Peter J. F. Snijders 21 colorectal cancer | Towards improved drugs, combinations and patient selection Hans-Joachim Schmoll and Alexander Stein The articles included in Nature Reviews Key Advances in Medicine were originally published online and in the February 2014 issues of the eight clinical Nature Reviews journals. The journals’ editors commissioned international experts to write a short essay highlighting up to eight key papers that made the biggest contribution to their field in 2013. Between them, the eight clinical Nature Reviews journals published 45 articles, which are collated in this eBook; if you choose to cite an article, please use the original journal citation rather than citing the eBook. We hope you enjoy reading Nature Reviews Key Advances in Medicine. If you would like to find out more about the Nature Reviews series, please visit: http://www.nature.com/reviews/ COPYRIGHT © 2014 Macmillan Publishers Limited. All rights reserved. Printed in the United Kingdom. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form (electronic or otherwise) without prior permission from permissions@ nature.com. DISCLAIMER: Although every effort is made by the publishers to see that no inaccurate or misleading data, opinions or statements appear in this collection, they wish to make it clear that the data and opinions appearing in articles and advertisements herein are the responsibility of the contributor or advertiser concerned. The journal does include the personal opinions of the authors; therefore, it is not intended to be relied on solely as a guide to good practice or safe treatment. Accordingly, the publishers, employees, offices and agents accept no liability whatsoever for the consequences of any such inaccurate or misleading data, opinion or statement. Although every effort is made to ensure that drug doses and other quantities are presented accurately, readers are advised that the new methods and techniques involving drug usage and described within this journal should only be followed in conjunction with the drug manufacturer’s own published literature. Don’t miss out on next year’s Key Advances in Medicine Sign up to free e-ALERTS and be notified when next year’s Key Advances in Medicine eBook is published. You won’t miss out on Nature Reviews collections and Focus issues either! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 3. Nature Reviews Endocrinology 23 puberty | Unravelling the mystery of puberty Sergio R. Ojeda and Alejandro Lomniczi 25 thyroid cancer | Advances in our understanding of differentiated thyroid cancer Christoph Reiners 27 steroid hormones | Glucocorticoids—timing, binding and environment Stafford L. Lightman and Charlotte L. George 29 type 2 diabetes mellitus | A central role of the gut in glucose homeostasis Geltrude Mingrone and Lidia Castagneto-Gissey 30 metabolism | The gut microbiota manages host metabolism Patrice D. Cani 32 adrenal cancer | Time to individualize treatment for adrenocortical cancer? Constantine A. Stratakis Nature Reviews Gastroenterology & Hepatology 35 hepatitis c | HCV causes systemic disorders that can be cured Francesco Negro 37 faecal microbiota transplantation | Developing human gut microbiota as a class of therapeutics Alexander Khoruts 38 coeliac disease | New insights in dietary-gluten‑induced autoimmunity Katri Kaukinen and Markku Mäki 40 barrett oesophagus | Risk stratification and surveillance in Barrett oesophagus Emmanuel C. Gorospe and Kenneth K. Wang 42 ibd | Enriching the therapeutic armamentarium for IBD Silvio Danese and Laurent Peyrin-Biroulet 44 small bowel endoscopy | The reality and the potential Uday C. Ghoshal Nature Reviews Nephrology 46 stem cells | Potential use of stem or progenitor cells for kidney regeneration Luigi Biancone and Giovanni Camussi 48 genetics in kidney disease | Susceptibility genes for renal and urological disorders Jasmin Divers and Barry I. Freedman 50 cardiovascular disease in ckd | Reducing cardiovascular risk —light at the end of the tunnel Jessica Kendrick and Michel Chonchol 51 transplantation immunology | New approaches to diagnosis of rejection Nicholas A. Zwang and Laurence A. Turka 53 acute kidney injury | Breaking barriers for biomarkers in AKI —progress at last Dinna N. Cruz and Ravindra L. Mehta Nature Reviews Neurology 56 epilepsy | Progress across the spectrum of epilepsy research Frances E. Jensen 58 movement disorders | Diagnosing and treating PD—the earlier the better? François Tison and Wassilios G. Meissner 59 stroke | Disappointments and advances in acute stroke intervention Michael Tymianski 61 neuro-oncology | Improving outcome in newly diagnosed malignant glioma Michael Weller and Wolfgang Wick 63 dementia | Frontotemporal lobar degeneration—building on breakthroughs Julie van der Zee and Christine Van Broeckhoven 65 multiple sclerosis | Novel triggers, treatment targets and brain atrophy measures Xavier Montalban and Mar Tintoré Nature Reviews Rheumatology 67 gout | Imaging, genetics and therapy: gout research continues apace Fiona M. McQueen 69 imaging in rheumatology | From images to data to theory Felix Eckstein and C. Kent Kwoh 71 systemic lupus erythematosus | Taking a closer look at biologic therapy for SLE David A. Isenberg and Anisur Rahman 72 epigenetics | DNA methylation and miRNA—key roles in systemic autoimmunity Bruce C. Richardson and Dipak R. Patel 74 rheumatoid arthritis | Translational medicine in RA—time for change Pierre Miossec Nature Reviews Urology 77 testicular cancer | Towards personalized medicine—are we there yet? Jan Oldenburg and Sophie D. Fosså 79 reconstruction | Recapitulating the urinary bladder—where are we heading? Arnulf Stenzl 80 bladder cancer | From genomics to imaging—advances along the care continuum Ahmed Haddad and Yair Lotan 83 female urology | Evaluating progress on longstanding issues Lindsey Cox and J. Quentin Clemens 84 prostate cancer | The changing role of imaging in clinical care Rahul Aggarwal and John Kurhanewicz 86 kidney cancer | From molecular understanding to clinical advances Chung-Han Lee and Robert J. Motzer © 2014 Macmillan Publishers Limited. All rights reserved
  • 4. KEY ADVANCES IN MEDICINE JANUARY 2014  |  1 CARDIOLOGY ACUTE CORONARY SYNDROMES IN 2013 Optimizing revascularization strategies in patients with ACS Gregg W. Stone Catheter-based revascularization has emerged as the gold-standard therapy for most patients with acute coronary syndromes (ACS). Optimizing outcomes in these patients requires appropriate adjunctive pharmacological therapy and percutaneous coronary intervention. Five studies published in 2013 are expected to have a major effect on treatment and prognosis of patients with ACS. Stone, G. W. Nat. Rev. Cardiol. 11, 67–68 (2014); published online 7 January 2014; doi:10.1038/nrcardio.2013.214 Acute coronary syndromes (ACS), which range from unstable angina to non-ST- segment elevation myocardial infarc- tion to ST-segment elevation myocardial infarction (STEMI), share a common ­pathophysiology—rupture of a lipid-rich, inflamed coronary artery atherosclerotic plaque with superimposed thrombosis. Over the past two decades, numerous ran­ domized trials have demonstrated that the preferred therapy for patients with ACS is urgent or emergent cardiac catheterization followed by revascularization as appro- priate, usually by percutaneous coronary intervention (PCI) with stent implantation. This approach reduces the rate of recurrent ischaemia, r­einfarction, and death, com- pared with more-conservative care. Within this framework, however, intense investi- gation has been ongoing to determine the optimal pharma­cological agents and treat- ment strategies to support PCI. In this Year in Review article, I discuss five important studies published in 2013, all of which will have a major effect on the treatment path- ways, prognosis, and future investigation of patients with ACS. Rapid reperfusion in STEMI using primary PCI, rather than administration of fibrinolytic agents, has been shown to save lives and prevent reinfarction and stroke.1 However, concerns regarding the effect of excessive delays to PCI have been expressed for patients who live >1 h away from a cardiac catheterization facil- ity. For such patients, a pharmacoinvasive approach has been suggested, consisting of early fibrino­lysis followed by transport­ ation to the interventional facility for either emergent PCI (in the case of failed fibrinolysis) or routine PCI, usually within 24 h. In the STREAM trial,2 1,892 patients presenting with STEMI who were unable to undergo primary PCI within 1 h were randomly assigned to a pharmaco­invasive approach (aspirin, clopidogrel, enoxa­ parin, and age-adjusted tenecteplase, fol- lowed by transportation to a PCI hospital and either emergent [36.3% of patients] or routine [63.7% of patients] angio­graphy) or to antiplatelet and antithrombin treat- ment according to local standards and transfer for immediate PCI. The primary end point of the composite of death, shock, congestive heart failure, or reinfarction up to 30 days occurred in 12.4% of patients in the fibrinolysis group and in 14.3% of patients in the primary PCI group (rela- tive risk [RR] for fibrinolysis 0.86, 95% CI 0.68–1.09, P = 0.21). Intracranial haemor- rhage was more common in the fibrinolysis group (1.0% versus 0.2%; P = 0.04).2 This study demonstrates that prehospital fibrino­ lysis with a pharmacoinvasive approach is a reasonable reperfusion strategy for patients with anticipated long delays in transfer for primary PCI. This approach avoids the need for emergent catheterization in two-thirds of patients, although primary PCI is still preferable unless the delays to transfer for PCI are truly excessive. The results of PCI in patients with ACS are improved with effective anti­platelet inhibition, especially with drugs that block the platelet P2Y12 receptor. Four such drugs are available for oral use: clopidog- rel, prasugrel, ticagrelor, and ticlopidine. These agents are most effective when given before PCI. However, all these drugs have delayed gastrointestinal absorption during STEMI, and inhibit platelet func- tion for 3–7 days, which can cause exces- sive bleeding after surgical procedures (for example, CABG surgery). Cangrelor is an investi­gational, potent, direct-acting, intravenously administered P2Y12 -receptor inhibitor with a half-life of 3–6 min. Platelet function is fully restored within 60 min of discontinuing this drug. The safety and effi- cacy of cangrelor compared with clopidog- rel were tested in 10,942 patients with ACS and stable coronary artery disease under- going PCI in the CHAMPION PHOENIX trial.3 Cangrelor, given intravenously at the time of PCI, reduced the primary efficacy end point of death, myocardial infarction, ischaemia-driven revascularization, or stent thrombosis at 48 h (4.7% versus 5.9% with clopidogrel; P = 0.005), without increasing MonkeyBusinessImages|Dreamstime.com © 2014 Macmillan Publishers Limited. All rights reserved
  • 5. 2  |  JANUARY 2014 www.nature.com/reviews CARDIOLOGY major bleeding.3 This novel agent could, therefore, have numerous applications in patients with ACS u­ndergoing PCI. Safe and effective procedural anti­ coagulation is essential to optimize the results of PCI in ACS. Among 3,602 patients with STEMI undergoing primary PCI in the randomized HORIZONS-AMI trial,4 use of the direct thrombin inhibitor bivali­ rudin reduced the 30‑day and 3‑year rates of major bleeding, thrombocyto­paenia, cardiac death, and all-cause mortality com- pared with unfractionated heparin plus a platelet glycoprotein IIb/IIIa inhib­itor (GPI), which was the previous standard of care. However, the HORIZONS-AMI trial4 was performed before the availabil- ity of the potent P2Y12 inhibitors prasugrel and ticagrelor, and before the widespread use of the radial artery to provide vas- cular access for PCI, which can reduce the risk of bleeding complications. In the EUROMAX trial,5 2,218 patients with STEMI were randomly assigned to heparin initiated in the ambulance, with or without a GPI, or to bivali­rudin alone, followed by transfer for primary PCI. In both groups, ~50% of the patients also received pra­ sugrel or t­icagrelor, and ~50% underwent PCI via radial artery access. The results of the EUROMAX trial5 at 30 days were very similar to those of the HORIZONS-AMI study,4 demonstrating a reduction in the primary end point of death or major bleed- ing with bivalirudin (5.1% versus 8.5% with the heparin strategy; RR 0.60, 95% CI 0.43–0.82, P = 0.005), as well as thrombo- cytopaenia.5 In both trials, however, stent thrombosis occurring within the first 24 h was more frequent with bivalirudin.4,5 In the future, this problem could be addressed with the pre-PCI use of cangrelor rather than prasugrel or ticagrelor. Embolization of thrombus and soft friable plaque down the coronary artery is ubiq­ uitous during primary PCI, and can cause capillary block, increased infarct size, heart failure, and death. Some, but not all, studies have indicated that removing the thrombus by mechanical aspiration before PCI (a fairly low-risk, simple pro­cedure) can prevent distal embolization and improve outcomes.6 These studies, however, were under­powered to be defin­itive. Using a nationwide Swedish registry system, the TASTE trial7 investi­ gators randomly allocated 7,244 patients with STEMI to primary PCI with or without thrombus aspiration. The primary end point of 30‑day mortality occurred in 2.8% of patients in the thrombus aspiration group versus 3.0% in the PCI-only group (HR 0.94, 95% CI 0.72–1.22, P = 0.63).7 Therefore, although thrombus aspiration was safe, no clear benefits were seen with the use of this pro­cedure. The TASTE trial7 is also notable for introducing the format of a randomized trial within a registry, allowing a very large- scale study to be completed fairly quickly and inexpensively. Primary PCI is typically performed on the infarct-causing coronary artery lesion only, because noncontrolled studies have suggested that multivessel PCI in this setting can be harmful.8 However, patients with ACS who have undergone successful PCI are at increased risk of recur­rent events arising from remote lesions in the coro- nary tree, owing to the frequent presence of other ‘vulnerable plaques’.9 The PRAMI study10 investigators, therefore, hypothe- sized that ‘preventative PCI’ of nonruptured coronary lesions might improve outcomes after STEMI. In the PRAMI trial,10 465 patients with STEMI and multivessel disease under­going primary PCI were ran- domly assigned to PCI of the infarct lesion only (control) or to PCI of all stenotic lesions (preventative PCI). During follow- up (mean 23 months), the primary end point of cardiac death, myocardial infarc- tion, or refractory angina was reduced in the preventative PCI group by 65% (HR 0.35, 95% CI 0.21–0.58, P <0.001), as was the rate of unplanned, repeat revascularization procedures (HR 0.30, 95% CI 0.17–0.56, P <0.001).10 Although this trial was too small to promote the preventative PCI approach as routine practice, this strategy might be of benefit in selected patients, and will certainly be examined in future, larger randomized trials. In summary, five important randomized trials were published in 2013 that have identi- fied optimal regimens and pharmaco­therapy usage strategies to support revascularization by PCI in high-risk patients with ruptured plaques and coronary thrombosis.2,3,5,7,10 Investigational drugs and novel treatment strategies are emerging that promise to con- tinue to improve the p­rognosis for patients with ACS. Competing interests The author declares associations with the following companies: Boston Scientific, Eli Lilly, and Daiichi Sankyo. See the article online for full details of the relationships. Columbia University Medical Center, The Cardiovascular Research Foundation, 111 East 59th Street, 11th Floor, New York, NY 10022, USA. gs2184@columbia.edu 1. Keeley, E. C., Boura, J. A. & Grines, C. L. Primary angioplasty versus intravenous thrombolytic therapy for acute myocardial infarction: a quantitative review of 23 randomised trials. Lancet 361, 13–20 (2003). 2. Armstrong, P. W. et al. Fibrinolysis or primary PCI in ST‑segment elevation myocardial infarction. N. Engl. J. Med. 368, 1379–1387 (2013). 3. Bhatt, D. L. et al. Effect of platelet inhibition with cangrelor during PCI on ischemic events. N. Engl. J. Med. 368, 1303–1313 (2013). 4. Stone, G. W. et al. Heparin plus a glycoprotein IIb/IIIa inhibitor versus bivalirudin monotherapy and paclitaxel-eluting stents versus bare-metal stents in acute myocardial infarction (HORIZONS-AMI): final 3‑year results from a multicentre, randomised controlled trial. Lancet 377, 2193–2204 (2011). 5. Steg, P. G. et al. Bivalirudin started during emergency transport for primary PCI. N. Engl. J. Med. 369, 2207–2217 (2013). 6. Kumbhani, D. J., Bavry, A. A., Desai, M. Y., Bangalore, S. & Bhatt, D. L. Role of aspiration and mechanical thrombectomy in patients with acute myocardial infarction undergoing primary angioplasty: an updated meta-analysis of randomized trials. J.Am. Coll. Cardiol. 62, 1409–1418 (2013). 7. Fröbert, O. et al. Thrombus aspiration during ST‑segment elevation myocardial infarction. N. Engl. J. Med. 369, 1587–1597 (2013). 8. Kornowski, R. et al. Prognostic impact of staged versus “one-time” multivessel percutaneous intervention in acute myocardial infarction: analysis from the HORIZONS-AMI (harmonizing outcomes with revascularization and stents in acute myocardial infarction) trial. J.Am. Coll. Cardiol. 58, 704–711 (2011). 9. Stone, G. W. et al. A prospective natural-history study of coronary atherosclerosis. N. Engl. J. Med. 364, 226–235 (2011). 10. Wald, D. S. et al. Randomized trial of preventive angioplasty in myocardial infarction. N. Engl. J. Med. 369, 1115–1123 (2013). Key advances ■■ A pharmacoinvasive strategy (fibrinolysis followed by cardiac catheterization) is a reasonable approach for patients with ST‑segment elevation myocardial infarction (STEMI) when percutaneous coronary intervention (PCI) is anticipated to be delayed2 ■■ The investigational intravenous antiplatelet agent cangrelor is superior to the most-widely used oral antiplatelet agent, clopidogrel, for the prevention of ischaemic complications when given at the time of PCI3 ■■ In patients with STEMI undergoing primary PCI, anticoagulation with bivalirudin has been confirmed to be the optimal antithrombotic regimen5 ■■ Thrombus aspiration was not shown to improve outcomes in patients with STEMI undergoing primary PCI7 ■■ ‘Preventative PCI’ of remote, nonculprit coronary lesions might prevent future ischaemic events in high-risk patients with STEMI10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 6. KEY ADVANCES IN MEDICINE JANUARY 2014  |  3 CARDIOLOGY HEART FAILURE IN 2013 Continue what we are doing to treat HF, but do it better Jay N. Cohn In 2013, clinical trials in heart failure focused on drugs and devices that might improve treatment of symptomatic patients beyond standard therapy. None achieved this aim. Therefore, future efforts should emphasize increased adherence to current, evidence-based therapy, and trials might better address efforts to prevent, rather than treat, heart failure. Cohn, J. N. Nat. Rev. Cardiol. 11, 69–70 (2014); published online 24 December 2013; doi:10.1038/nrcardio.2013.212 The principles of managing heart failure (HF) became apparent decades ago. When the left ventricle is dilated and under­ going the process of remodelling,1 function can be improved with vasodilatory drugs that reduce impedance to left ventricular ejection. These drugs augment the favour- able effect of diuretics on symptoms and exercise tolerance in patients with HF. Life prolongation, however, is dependent on inhibition of the remodelling, which can be accomplished by neurohormone inhibitors,1 with or without vasodilatory properties, by drugs that enhance nitric oxide activity, and by electrical resynchronization of the ven- tricles.2 However, the therapies used to treat HF with reduced ejection fraction (HFrEF) exhibit little benefit when the ventricle is not dilated—a syndrome now called HF with p­reserved ejection fraction (HFpEF). Trials conducted in the past few years have been devoted to efforts to improve strategies for using effective treatments in HFrEF, and tofindatreatmentforHFpEFthatcanreduce symptomsorimproveoutcomes.Commercial sponsors have sought new drugs or devices, or expanded the use of existing interventions for HFrEF, whereas government sponsors have tried to document the best methods for employing existing treatments. New m­echanistic ­breakthroughs have been scarce. In 2013, this pattern was dramatically apparent. Dissatisfaction with current loop diuretic therapy for acute decompensated HF has generated a number of studies to replace or supplement such drugs. These efforts have generally failed to reveal a more-effective alternative. The Heart Failure Clinical Research Network, funded by the National Heart, Lung, and Blood Institute in the USA, addressed the possibility that low- dose dopamine or low-dose nesiritide could safely augment the diuresis induced by loop diuretics in patients with decompensated HF. The trial, in 360 patients, showed no evidence that diuresis or decongestion was enhanced by such combined therapy or that renal func- tion was better preserved.3 The conclusion is that we should continue what we are doing— maintain an aggressive approach to diuretic therapy, and perhaps concern ourselves less when renal function transiently worsens. Cardiac resynchronization therapy (CRT) has been remarkably effective in improv- ing quality of life and prolonging survival in patients with HFrEF and an electro­ cardiogram(ECG)-measuredprolong­ationof the QRS complex.2 The assumption has been that the ECG abnorm­ality served as a crude surrogate for ventricular dyssynchrony that could be used to distinguish responders from nonresponders. The EchoCRT Study Group,4 funded by Biotronik and GE Healthcare, con- ducted an international trial at 115 centres in 809 patients with HFrEF and demon- strable ventricular dyssynchrony despite a QRS duration <130 ms (the usual cut-off for CRT eligibility). Not only was CRT in such patients ineffective in terms of the primary end point—death or first hospitalization for HF—but a significant increase in mortality occurred in the CRT group.4 Once again, good reasons exist not to change what we are currently doing, even if the QRS criterion seems imprecise. As in all studies of CRT, however, individual variability in the mecha- nisms of HF progression and in the electrical characteristics of ventricular depolarization renders all large-trial data not n­ecessarily applicable to individual patients. Many studies in 2013 focused on patients with HFpEF, both because of the growing recognition of its prevalence and because of the absence of an effective or approved therapy. An attractive potential therapy was phosphodiesterase‑5 (cGMP-specific 3',5'‑cyclic phosphodiesterase) inhibition, which augments cyclic GMP and, therefore, generates nitric oxide. Preliminary studies in this syndrome demonstrated a favourable haemodynamiceffectofp­hosphodiesterase-5 inhibition. Investigators in the RELAX trial,5 funded largely by the NIH, studied the effect of sildenafil in 216 patients with sympto- matic HF and an ejection fraction ≥50%. After 24 weeks of therapy with sildenafil or placebo, no difference was observed between groups in either peak exercise capacity or clinical status. Consistently with other trials in patients with HFpEF, therefore, no thera- peutic benefit of the e­xperimental treatment could be demonstrated. Ivabradine has exhibited a dramatic ben­­efit inoutcomesinpatientswith HFrEF.6 Whether heart-rate slowing with this If ‑channel inhibitor could favourably affect the course of HFpEF was the subject of a small trial in 61 patients from Poland and Australia.7 This short, 7‑day, placebo-controlled­trial showed a significant increase in peak exer- cise capacity between baseline and follow- up (4.2 ± 1.8 metabolic equivalents versus 5.7 ± 1.9 metabolic equivalents; P = 0.001), pres­umably mediated by the haemodynamic effects of heart-rate slowing. To determine whether this pharmacological effect results in a significant improvement in quality of life in patients HFpEF requires a far larger trial of longer duration. However, nothing in the data or the known mechan­ism of drug action would generate optimism about a ­long-termfavourableeffectonmorbidevents. A more-attractive therapeutic approach to HFpEF is the use of spironolactone, Key advances ■■ Infusion of low-dose dopamine or nesiritide did not increase urinary output, further relieve congestion, or protect renal function in patients with acute decompensated heart failure already treated with conventional therapy3 ■■ Resynchronization therapy in patients with ventricular dyssynchrony, but normal QRS duration, was ineffective in improving symptoms of heart failure4 ■■ Phosphodiesterase‑5 inhibition did not improve symptoms in patients with heart failure with preserved ejection fraction (HFpEF) in a 24‑week study5 ■■ Ivabradine to slow heart rate in patients with HFpEF improved diastolic function and increased maximal exercise capacity in a 7‑day trial7 ■■ Outcome data with spironolactone have been disappointing, despite the beneficial effect of this drug on diastolic function and exercise capacity in a 1‑year study of patients with HFpEF9 © 2014 Macmillan Publishers Limited. All rights reserved
  • 7. 4  |  JANUARY 2014 www.nature.com/reviews CARDIOLOGY which has demonstrated favourable long- term effects in patients with HFrEF and is thought to inhibit collagen synthesis, which is involved in stiffening of the left ventricle and inducing the diastolic dysfunction that might be a critical aetiological factor in HFpEF.8 The Aldo‑DHF trial,9 supported by a German government agency, was con- ducted in 422 patients from Germany and Austria with HFpEF and diastolic dysfunc- tion. After 12 months of follow-up, the investigators noted that the spironolactone- treated group exhibited a reduction in left ventricular mass (adjusted mean differ- ence −6 g/m2 ; 95% CI −10 g/m2 to −1 g/m2 , P = 0.009) and an improvement in diastolic left ventricular function (adjusted mean dif- ference in E/e' −1.5; 95% CI −2.0 to −0.9, P <0.001).9 Exercise performance and HF symptoms, however, were not improved.9 A more-definitive evaluation of spirono- lactone in HFpEF was carried out in the TOPCAT trial,10 sponsored by the US National Heart, Lung, and Blood Institute. The long-awaited results of this multi­ national trial involving 3,445 patients was reported at the AHA Scientific Sessions in November 2013, but have not yet been published in a peer-reviewed journal. After follow-up (mean 3.3 years), the difference in morbid events between the spirono­ lactone and placebo groups was about 10% and did not reach statistical significance.10 Therefore, despite the attractiveness of the concept, spironolactone, as with all other drugs known to inhibit left ventricular struc- tural remodelling through neuro­hormonal m­echanisms, has failed to alter the course of HFpEF. Two messages emerge from all these trials that have not further reduced morbidity and mortality in HF beyond that achieved with existing treatments. First, our current, evidence-based therapy, properly employed, produces as much benefit as we can reason­ ably expect in both HFrEF and HFpEF. The gap between routine clinical practice and knowledgeable care, however, remains tr­oubling, and efforts to close that gap could yield dramatic population benefits. The second and more-subtle message is that treatment instituted late in the disease process has, at most, modest benefits. Efforts to prevent HF should yield far greater long- term benefits. HF, as with all cardiovascular morbid events, is a progressive process that can be detected long before symptoms occur. Early detection of the HF phenotype should identify individuals who might be particu- larly responsive to therapeutic interventions to slow its progression (Figure 1). We might hope that 2014 and subsequent years will bring a growing interest in trials aimed at preventing disease. In HFrEF, early detection should allow interventions with inhibitors of left ventricular remodel- ling that could substantially prolong life. In HFpEF, the dysfunction of the left ventricle is probably an ageing effect on the vasculature and myocardium that is largely unrespon- sive to therapy, but might be substantially delayed by early intervention. Trials to docu- ment such therapeutic efficacy are urgently needed. Such trials in years to come will hopefully demonstrate more t­herapeutic potential than the trials of 2013. Age (years) Leftventricularremodelling Natural history Treatment Prevention Symptoms Death Figure 1 | The natural history of heart failure exhibits age-dependent progression of left ventricular remodelling, with the development of symptoms and premature death. Treatment after symptoms develop is aimed at reversing or slowing progression of these symptoms and delaying death. Clinical trials in 2013 were largely unsuccessful in accomplishing benefit beyond that of background therapy. Preventive therapy instituted before symptom development should be more effective in preventing symptoms and prolonging life. Cardiovascular Division, University of Minnesota Medical School, Mayo Mail Code 508, 420 Delaware Street Southeast, Minneapolis, MN 55455, USA. cohnx001@umn.edu Competing interests The author declares no competing interests. 1. Cohn, J. N. Structural basis for heart failure: ventricular remodeling and its pharmacological inhibition. Circulation 91, 2504–2507 (1995). 2. Bristow, M. R. et al. Cardiac-resynchronization therapy with or without an implantable defibrillator in advanced chronic heart failure. N. Engl. J. Med. 350, 2140–2150 (2004). 3. Chen, H. H. et al. Low-dose dopamine or low- dose nesiritide in acute heart failure with renal dysfunction: the ROSE acute heart failure randomized trial. JAMA http://dx.doi.org/ 10.1001/jama.2013.282190. 4. Ruschitzka, F. et al. Cardiac-resynchronization therapy in heart failure with a narrow QRS complex. N. Engl. J. Med. 369, 1395–1405 (2013). 5. Redfield, M. M. et al. Effect of phosphodiesterase‑5 inhibition on exercise capacity and clinical status in heart failure with preserved ejection fraction: a randomized clinical trial. JAMA 309, 1268–1277 (2013). 6. Swedberg, K. et al. Ivabradine and outcomes in chronic heart failure (SHIFT): a randomised placebo-controlled study. Lancet 376, 875–885 (2010). 7. Kosmala, W. et al. Effect of If ‑channel inhibition on hemodynamic status and exercise tolerance in heart failure with preserved ejection fraction: a randomized trial. J. Am. Coll. Cardiol. 62, 1330–1338 (2013). 8. Pitt, B. et al. The effect of spironolactone on morbidity and mortality in patients with severe heart failure. N. Engl. J. Med. 341, 709–717 (1999). 9. Edelmann, F. et al. Effect of spironolactone on diastolic function and exercise capacity in patients with heart failure with preserved ejection fraction: the Aldo‑DHF randomized controlled trial. JAMA 309, 781–791 (2013). 10. Pfeffer, M. A. Treatment of preserved cardiac function heart failure with an aldosterone antagonist (TOPCAT). Presented at the American Heart Association Scientific Sessions 2013. VENOUS THROMBOEMBOLISM IN 2013 The advent of the novel oral anticoagulants Paolo Prandoni New findings published in 2013 strongly support the use of novel oral anticoagulants in the treatment of thromboembolic disorders. These drugs have been shown to have a more-favourable benefit-to-risk profile than older compounds, enabling their use from the start of treatment and in the whole spectrum of clinical presentations. Prandoni, P. Nat. Rev. Cardiol. 11, 70–72 (2014); published online 14 January 2014; doi:10.1038/nrcardio.2013.210 The availability of antithrombotic com- pounds that can be administered orally in fixed doses without the need for laboratory control, owing to their predict- able pharmaco­kinetics and pharmaco­ dynamics and low potential for drug and © 2014 Macmillan Publishers Limited. All rights reserved
  • 8. KEY ADVANCES IN MEDICINE JANUARY 2014  |  5 CARDIOLOGY food interactions, has opened new horizons for the treatment of patients with venous thrombo­embolism (VTE). These drugs include three factor Xa inhibitors (apixaban, edoxaban, and rivaroxaban) and a direct thrombin inhibitor (dabigatran etexilate). For three of these four compounds (apixa- ban, dabigatran, and edoxaban) the results of l­andmark trials have been p­ublished in 2013. The efficacy of apixaban for the initial treatment of VTE was investigated in the AMPLIFY study,1 a randomized, double- blind trial in which apixaban (10 mg twice daily for 7 days followed by 5 mg twice daily for 6 months) was compared with enoxa- parin followed by warfarin (conventional therapy) for the treatment of 5,400 patients with acute VTE, of whom one-third had pulmonary embolism. Recurrent VTE or VTE-associated death occurred in 59 patients in the apixaban group (2.3%) and 71 (2.7%) in the conventional therapy group (relative risk [RR] 0.84, 95% CI 0.60–1.18, P <0.001 for noninferiority). Major bleed- ing occurred in 15 (0.6%) and 49 patients (1.8%) in these two groups, respectively (RR 0.31, 95% CI 0.17–0.55, P <0.001 for superiority). Major and clinically relevant nonmajor bleeding occurred in 4.3% and 9.7% of these groups, respectively (RR 0.44, 95% CI 0.36–0.55, P <0.001). The results of this study suggest that the advent of novel anticoagulants has enabled antithrombotic benefits to be dissociated from haemor- rhagic potential to a much greater extent than with the older drugs. In addition, analogous with the strategy adopted for rivaroxaban,2,3 apixaban was administered from the beginning of treatment in the AMPLIFY trial,1 without the need for initial parenteral heparin treatment. The suitabil- ity of a few emerging compounds that are effective and safe for patients with VTE from the start of treatment opens new and interesting scenarios for the management of these disorders. Firstly, a greater propor- tion of patients will be able to be treated directly at home than is currently possible. Secondly, treatment of these disorders will become immediately feasible with oral com- pounds, whenever the clinical suspicion of VTE arises, without the need for inconven- ient parenteral drugs, the use of which can require l­aboratory s­urveillance and medical expertise. In the AMPLIFY-EXT trial,4 2,500 patients who had completed 6–12 months of treatment for deep-vein thrombosis or pulmonary embolism were randomly assigned to receive apixaban 2.5 mg twice daily, apixaban 5.0 mg twice daily, or placebo for 12 months. Both doses of apixaban demonstrated superiority compared with placebo in the reduction of the composite end point of symptomatic, recurrent VTE and death from any cause (3.8% and 4.2% in the 2.5 mg and 5.0 mg apixaban groups, respectively, versus 11.6% in the placebo group; P <0.001). Apixaban was also super­ ior to placebo for the predefined second- ary efficacy outcome of recurrent VTE and VTE-associated death (1.7% in both the apixaban groups versus 8.8% in the placebo group; P <0.001). The rate of major bleed- ing was comparable for the 2.5 mg (0.2%) and 5.0 mg (0.1%) doses of apixaban and for placebo (0.5%). The rate of the compo­ site of major bleeding and clinically rel- evant nonmajor bleeding for the 5.0 mg apixa­ban group (4.3%) was higher than in the placebo group (2.7%), whereas the rate in the 2.5 mg apixaban group (3.2%) was similar to that with placebo.4 The RE‑SONATE5 and the RE‑MEDY5 clinical trials were designed to assess the value of dabigatran for the extended treat- ment of VTE. The efficacy and safety of this antithrombin compound for the treatment of acute VTE had already been demonstrated 4 years previously in the RE‑COVER trial.6 In the RE‑SONATE study,5 1,343 patients with VTE who had completed 6–18 months of anticoagulant therapy were randomly assigned to receive dabigatran (150 mg twice daily) or placebo for an additional period of 6 months. A 92% reduction in the relative risk of recurrent VTE was shown with dabigatran, with a low risk of major bleeding (0.3%). In the RE‑MEDY study,5 2,856 patients treated for 6 months with vitamin K antagonists for a first VTE were randomly assigned to receive dabigatran (150 mg twice daily) or warfarin (treated to a target international normal- ized ratio of 2–3) and followed up for up to 3 years. Dabigatran was shown to be noninferior to warfarin in terms of the primary outcome of recurrent or fatal VTE (1.8% versus 1.3%; HR 1.44, 95% CI 0.78–2.64, P = 0.01 for noninferiority). Major bleeding complications occurred in 0.9% and 1.8% of patients in the dabigatran and warfarin groups, respectively (48% ­reduction in r­elative risk with dabigatran). The results of the RE‑SONATE and RE‑MEDY studies5 consolidate and expand those obtained in the AMPLIFY-EXT study4 by providing the first head-to-head comparison between a novel anticoagulant drug and warfarin in the extended treat- ment of patients with VTE. The findings are consistent with those already obtained with rivaroxaban 2 years previously,2 and open new avenues for the long-term treatment of patients with unprovoked VTE. Indeed, the availability of drugs with better safety profiles than vitamin K antagonists raises the possibility of extended periods of anti- coagulation for patients whose natural clini- cal course in the absence of anti­­coagulation is characterized by a VTE recurrence rate ~50%.7 The results of the AMPLIFY-EXT study4 suggest that halving the initial dose of apixaban after the first 6 months in patients with unprovoked VTE is likely to preserve protection against recurrent VTE, while reducing the haemorrhagic potential.4 Novel oral anticoagulant shop NPG Key advances ■■ The availability of compounds that can be used from the beginning of treatment for venous thromboembolism (VTE) has the potential to streamline therapy, making outpatient management feasible1 ■■ The improved safety profile of novel anticoagulants compared with older compounds makes prolonged anticoagulation therapy for patients with unprovoked VTE a realistic possibility4,5 ■■ Favourable outcomes among patients with severe pulmonary embolism treated with novel anticoagulants challenges the view that aggressive thrombolytic treatment should be considered for all patients with right ventricular dysfunction8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 9. 6  |  JANUARY 2014 www.nature.com/reviews CARDIOLOGY DYSLIPIDAEMIA IN 2013 New statin guidelines and promising novel therapeutics Dimitri P. Mikhailidis and Vasilios G.Athyros The new ACC/AHA guidelines on treatment of blood cholesterol focus on intensity of statin therapy rather than target levels of lipids. Early studies show substantial reductions in LDL-cholesterol level with antibodies against PCSK9. MicroRNA silencing and gene-repair techniques to treat dyslipidaemia are promising strategies under development. Mikhailidis, D. P. & Athyros, V. G. Nat. Rev. Cardiol. 11, 72–74 (2014); published online 24 December 2013; doi:10.1038/nrcardio.2013.209 In this Year in Review article, we discuss the main advances in the prevention and treat- ment of dyslipidaemia during 2013. The new ACC/AHA practice guidelines for the treat- ment of blood cholesterol, the aim of which is to reduce the risk of atherosclerotic cardio- vasculardisease(ASCVD),includenewequa- tions to estimate this risk.1 These equations are based on the pooled results of five large cohort studies and consider age, sex, ethnic- ity, total-cholesterol and HDL-cholesterol (HDL‑C) levels, systolic blood pressure, presence of diabetes mellitus, smoking status, and treatment for hypertension.1 As in the Framingham equation, a family history of premature ASCVD is missing, but the risk of stroke is included, which is useful. These guidelines do not set treatment targets for LDL cholesterol (LDL‑C) or non-HDL‑C.1 Instead, they focus on the intensity of statin therapy to reduce ASCVD risk in combin­ ation with a healthy lifestyle.1 High-intensity statin therapy, which lowers the LDL‑C level by≥50%,isrecommendedmainlyforthesec- ondary prevention of ASCVD. Moderate-to- highintensitystatintherapy,whichlowersthe LDL‑C level by 30–50%, is recommended for primary prevention in patients at high risk of ASCVD. Low-intensity statin therapy, which lowers the LDL‑C level by <30%, is recom- mended for primary prevention in patients at m­oderate-to-low risk of ASCVD.1 These recommend­ations are conceptually different from those in previous guidelines, which set The results from the randomized, double- blind Hokusai‑VTE trial,8 addressing the efficacy of edoxaban, were also published in 2013. After initial treatment with parenteral drugs, 4,921 patients with deep-vein throm- bosis and 3,319 individuals with pulmonary embolism (associated with right ventricular dysfunction in approximately one-third of trial participants) were allocated to receive edoxaban 60 mg once daily (30 mg in patients with moderate renal failure, body weight <60 kg, or both), or warfarin for 3–12 months at the discretion of attending physicians. At 1 year, edoxaban was non­ inferior to warfarin with respect to the inci- dence of recurrent VTE, which occurred in 130 patients in the edoxaban group and 146 in the warfarin group (3.2% versus 3.5%; HR 0.89, 95% CI 0.70–1.13, P <0.001 for noninferiority). Major or clinically relevant bleeding complications occurred in 349 and 423 of patients in these groups, respectively (8.5% versus 10.3%; HR 0.81, 95% CI 0.71– 0.94, P = 0.004 for superiority). Interestingly, when the analysis was confined to the 938 patients with pulmonary embolism and right ventricular dysfunction, VTE com- plications were significantly less frequent in patients allocated to edoxaban than in those who received warfarin (3.3% versus 6.2%; HR 0.52, 95% CI 0.28–0.98). These find- ings are consistent with those obtained in the EINSTEIN‑PE study,3 and challenge the growing view that an aggressive thrombo­ lytic treatment should be considered for all patients with pulmonary embolism who exhibit biochemical character­istics (assessed using laboratory tests) or find- ings on ultrasonography compatible with right ventricular dysfunction despite appar- ent clinical and haemodynamic stability.9 Additional interesting findings are that halving the dose in selected patients does not impair the overall efficacy of edoxaban, and that efficacy is preserved after discon- tinuation of the drug, which was achieved after 3–6 months in approximately 60% of patients.8 After 50 years without any substantial progress, antithrombotic treatment of patients with VTE has finally evolved. On the basis of results from studies published in 2013, novel anticoagulants such as apixaban, dabigatran, and edoxaban could conceiv­ ably become standard therapy for VTE in the next few years. However, clinical data are still absent for the long-term safety and efficacy of these drugs. The optimal management of bleeding complications in patients receiving these novel anti­coagulants remains unclear, and their use in patients with severe renal failure requires caution. Studies addressing the benefits and the risks of these drugs in patients with cancer and VTE, and in pregnant women, are needed. Although the current absence of specific antidotes to the novel anticoagulants is a major concern, several potential antidotes are being investigated with a good chance of successful development.10 Department of Medicine,Vascular Medicine Unit, University of Padua,Via Giustiniani 2, 35028 Padua, Italy. paoloprandoni@tin.it Competing interests The author declares associations with the following companies: Bayer, Boehringer Ingelheim, Daiichi Sankyo, and Pfizer. See the article online for full details of the relationships. 1. Agnelli, G. et al. Oral apixaban for the treatment of acute venous thromboembolism. N. Engl. J. Med. 369, 799–808 (2013). 2. Bauersachs, R. et al. Oral rivaroxaban for symptomatic venous thromboembolism. N. Engl. J. Med. 363, 2499–2510 (2010). 3. Büller, H. R. et al. Oral rivaroxaban for the treatment of symptomatic pulmonary embolism. N. Engl. J. Med. 366, 1287–1297 (2012). 4. Agnelli, G. et al. Apixaban for extended treatment of venous thromboembolism. N. Engl. J. Med. 368, 699–708 (2013). 5. Schulman, S. et al. Extended use of dabigatran, warfarin, or placebo in venous thromboembolism. N. Engl. J. Med. 368, 709–718 (2013). 6. Schulman, S. et al. Dabigatran versus warfarin in the treatment of acute venous thromboembolism. N. Engl. J. Med. 361, 2342–2352 (2009). 7. Prandoni, P. et al. The risk of recurrent venous thromboembolism after discontinuing anticoagulation in patients with acute proximal deep vein thrombosis or pulmonary embolism: a prospective cohort study in 1,626 patients. Haematologica 92, 199–205 (2007). 8. Büller, H. R. et al. Edoxaban versus warfarin for the treatment of symptomatic venous thromboembolism. N. Engl. J. Med. 369, 1406–1415 (2013). 9. Konstantinides, S. & Goldhaber, S. Z. Pulmonary embolism: risk assessment and management. Eur. Heart J. 33, 3014–3022 (2012). 10. Prandoni, P., Barbar, S., Milan, M., Vedovetto, V. & Pesavento, R. The risk of recurrent thromboembolic disorders in patients with unprovoked venous thromboembolism: new scenarios and opportunities. Eur. J. Intern. Med. http://dx.doi.org/10.1016/j.ejim.2013.09.005. © 2014 Macmillan Publishers Limited. All rights reserved
  • 10. KEY ADVANCES IN MEDICINE JANUARY 2014  |  7 CARDIOLOGY [ASO]thattargetsapolipoprotein BmRNAto reduceLDLsynthesis)andlomitapide(which inhibits the microsomal trigly­ceride transfer protein, necessary for VLDL-cholesterol pro- duction), which have already been approved. These novel drugs will be available to lower the LDL‑C level in patients with all forms of acquired or hereditary dyslipidaemia, and will increase the percentage of patients at high risk of ASCVD who attain target lipid levelsbeyondthatwhichcanbeachievedwith statin treatment alone.2,4–7 Other therapeutic strategies have been in development during 2013. A specific Key advances ■■ The new ACC/AHA guidelines on the treatment of blood cholesterol specify the intensity of statin therapy rather than defining target LDL-cholesterol levels1 ■■ Antibodies against proprotein convertase subtilisin/kexin type 9 are a promising novel therapy for dyslipidaemia and atherosclerosis2,6 ■■ The development of efficacious adjunct therapies to statins will increase the numbers of patients who reach their target LDL-cholesterol level2,6 ■■ MicroRNA‑33 is involved in cell cholesterol efflux; silencing this microRNA (or others) might prove to be clinically beneficial8 ■■ Genetic engineering, currently being used to investigate gene-repair techniques in mice, is a potentially substantial advance in future treatments for dyslipidaemia and atherosclerosis9 target LDL‑C levels. Nonalcoholic fatty liver disease and rheumatoid arthritis—high-risk equivalents in some previous guidelines— are not mentioned. The new guidelines focus on the benefits of statin treatment as estab- lished by prospective, randomized, placebo- controlle­d studies with cardiovascular end points. However, some patients will not achieve a target LDL‑C level (as is still rec- ommended by the ESC and the European Atherosclerosis Society) with statins. This category of patients includes those intoler- ant to statins, and many with familial hyper- cholesterolaemia (FH), for whom other ­treatment options are needed. An LDL receptor binds a single LDL par- ticle and is internalized; the receptor then leaves the LDL particle inside the cell before recycling to the cell surface. Proprotein convertase subtilisin/kexin type 9 (PCSK9) enhances the degradation of LDL receptors.2 Therefore, monoclonal antibodies against PCSK9 prolong LDL-receptor activity, result- ing in a reduced circulating LDL‑C level.2 The effect of decreased PCSK9 activity was shown in the 15‑year follow-up of the ARIC study3 (n = 12,887).ParticipantswithaPCSK9 nonsense mutation had a substantially lower LDL‑C level and rate of ASCVD events (reduced by up to 88%) than i­ndividuals with optimal PCSK9 function.3 In the phase II LAPLACE‑TIMI 57 trial,2 the fully human, monoclonal, IgG2, antibody AMG 145 (Amgen, USA; drug now known as evolocumab) was administered sub­cutan­ e­ously at various doses and was compared with placebo in 631 individuals with hyper- cholesterolaemia (LDL‑C level >85 mg/dl; 45% at high risk of ASCVD). Participants also received a stable dose of a statin, with or without ezetimibe. Up to 90% and 97% of individualsreceivingAMG 145every2 weeks or 4 weeks, respectively, attained the LDL‑C target level of <70 mg/dl (P <0.001 versus placebo).2 Additionally,upto90%and97%of high-risk individuals treated with AMG 145 at the same time intervals achieved the triple target of LDL‑C level <70 mg/dl, apolipo- protein B level <80 mg/dl, and non-HDL‑C level <100 mg/dl (P <0.001 versus placebo, for all targets and all doses of AMG 145).2 Therefore, adding AMG 145 to background statin therapy, with or without ezetimibe, sig- nificantly increases the likelihood of patients at high risk of ASCVD achieving the target levels of LDL‑C and other lipids.2 Another analysis from the LAPLACE- TIMI 57study,4 showedthatAMG 145signif- icantly reduces the leveloflipoprotein(a)—an emerging vascular risk factor—by ≤32%. A two-part, phase II–III study to assess the safety, tolerability, and efficacy of AMG 145 in individuals (n = 8) with homozygous FH has also been published.5 This study included subcutaneous injection of AMG 145 at a dose of 420 mg every 4 weeks for >12 weeks, and then every 2 weeks for an additional 12 weeks.5 In the two LDL-receptor-negative patients, no reduction in the LDL‑C level occurred. Over the two treatment periods, the mean reductions in LDL‑C level in the sixpatientswithdefectiveLDLreceptorswere 19.3%and26.3%withthe4‑weekand2‑week dosing regimens, respectively (P = 0.03 for each).5 Data from the OSLER study,6 in which 1,104 patients with hypercholesterol­ aemia were followed up for ≥1 year and given evolocumab every 4 weeks, supported the long-term efficacy, safety, and tolerability of the drug.6 A phase III study involving 25,000 patients with hypercholesterolaemia has been initiated to evaluate the incremental clinical benefit of evolocumab in patients at high risk of ASCVD, whose LDL‑C level is not adequately controlled with maximum-dose statin treatment plus ezetimibe therapy. As with AMG 145, the PCSK9 inhibitor alirocumab (Sanofi, France and Regeneron, UK) has been shown to reduce the LDL‑C level by 40–72% when administered in addi- tion to atorvastatin in 183 patients with an LDL‑C level ≥100 mg/dl.7 Therefore, data from phase II–III trials indicate that PCSK9 inhibitors will hopefully be added to the list of novel lipid-lowering drugs—together with mipomersen (an antisense oligonucleotide Cytoplasm MicroRNA gene or intron Transcription Pri-microRNA Cleavage Pre-microRNA 5' 3' Exportin-5 GTP Ran Nuclear export 5' 3' Pre-microRNA Cleavage Dicer TRBP MicroRNA duplex Mature microRNA RISC formation Degradation mRNA target cleavage Translational repression mRNA deadenylation RNA Pol II/III Drosha DGCR8 5' 3' 5' 3' 3' 5' Ago2 5' 3' 5' 3' Nucleus Figure 1 | microRNA maturation and gene repression. Pre‑microRNA is exported from the nucleus and cleaved in the cytoplasm to its mature length. The functional (red) strand of the mature microRNA, together with ago2 proteins, guides the RISC to silence target mRNAs via mRNA cleavage, translational repression, or deadenylation. Abbreviations: Ago2, protein argonaute‑2; Dicer, endoribonuclease Dicer; Drosha, ribonuclease 3; DGCR8, microprocessor complex subunit DGCR8; Pol II/III, polymerase II or III; Ran, GTP-binding nuclear protein Ran; RISC, RNA-induced silencing complex; TRBP, RISC-loading complex subunit TARBP2. Permission obtained from Nature Publishing Group © Winter, J. et al. Nat. Cell Biol. 11, 228–234 (2009). © 2014 Macmillan Publishers Limited. All rights reserved
  • 11. 8  |  JANUARY 2014 www.nature.com/reviews CARDIOLOGY microRNA, miR‑33, has been shown to repress several genes involved in cellular cholesterol trafficking (Figure 1).8 In chow- fed Lldr–/– mice injected with anti-miR‑33 ASO,theHDL‑Clevelandcellularcholesterol efflux increased, whereas plaque size and macrophage content significantly decreased, compared with mice injected with a placebo or nontargeting ASO.8 By contrast, anti- miR‑33 ASO did not increase the HDL‑C level when mice were fed a Western diet, but a significant reduction in athero­sclerotic plaque size was observed.8 These effects might be useful in reducing residual ASCVD risk, even after effective LDL‑C control. An animal gene-repair study might herald a new era in the treatment of dyslipid­­­aemia and atherosclerosis.9 Apoe gene repair was performed in chow-fed hypomorphic apolipo­protein E mice that are deficient in LDL-receptor expression and which develop hyperlipidaemia and atherosclerosis.9 Gene repair was associated with a twofold reduc- tion in plasma LDL‑C and triglyceride levels and a decrease in the ratio of non- HDL‑C to HDL‑C.9 This intervention also halted ather­oma lesion growth, and pro- moted both macro­phage loss and accumu­ lation of collagen, without changes in other genes i­mplicated in cholesterol efflux or in inflammation.9 In 2013, statins remain the cornerstone of lipid-lowering treatment. However, mono- clonal antibodies that delay LDL-receptor degradation, anti-microRNA ASO, and the repair of genes implicated in hyperlipidaemia are on the horizon. Cost-effectiveness might be a substantial limiting factor to introducing these novel therapies into clinical practice. Department of Clinical Biochemistry (Vascular Prevention Clinic), Royal Free Hospital Campus, University College School of Medicine, Pond Street, London NW3 2QG, UK (D. P. Mikhailidis). Atherosclerosis and Metabolic Syndrome Outpatient Units, Medical School, Aristotle University of Thessaloniki, Hippokration Hospital, 15 Marmara Street, 55132 Thessaloniki, Greece (V. G. Athyros). Correspondence to: D. P. Mikhailidis mikhailidis@aol.com Competing interests D. P. Mikhailidis declares associations with the following companies: Genzyme and MSD. See the article online for full details of the relationships. V. G. Athyros declares no competing interests. 1. Stone, N. J. et al. 2013 ACC/AHA guideline on the treatment of blood cholesterol to reduce atherosclerotic cardiovascular risk in adults: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation http://dx.doi.org/10.1161/ 01.cir.0000437738.63853.7a. 2. Desai, N. R. et al. AMG 145, a monoclonal antibody against PCSK9, facilitates achievement of NCEP‑ATP III LDL‑C goals among high risk patients: an analysis from the LAPLACE‑TIMI 57 trial. J.Am. Coll. Cardiol. http://dx.doi.org/ 10.1016/j.jacc.2013.09.048. 3. Cohen, J. C., Boerwinkle, E., Mosley, T. H. Jr & Hobbs, H. H. Sequence variations in PCSK9, low LDL, and protection against coronary heart disease. N.Engl.J.Med. 354,1264–1272 (2006). 4. Desai, N. R. et al. AMG 145, a monoclonal antibody against proprotein convertase subtilisin kexin type 9, significantly reduces lipoprotein(a) in hypercholesterolemic patients receiving statin therapy. Circulation 128, 962–969 (2013). 5. Stein, E. A. et al. Effect of the proprotein convertase subtilisin/kexin 9 monoclonal antibody, AMG 145, in homozygous familial hypercholesterolemia. Circulation 128, 2113–2120 (2013). 6. Koren, M. J. et al. Efficacy and safety of longer- term administration of evolocumab (AMG 145) in patients with hypercholesterolemia. Circulation http://dx.doi.org/10.1161/ CIRCULATIONAHA.113.007012. 7. McKenney, J. M. et al. Safety and efficacy of a monoclonal antibody to proprotein convertase subtilisin/kexin type 9 serine protease, SAR236553/REGN727, in patients with primary hypercholesterolemia receiving ongoing stable atorvastatin therapy. J.Am. Coll. Cardiol. 59, 2344–2353 (2012). 8. Rotllan, N., Ramírez, C. M., Aryal, B., Esau, C. C. & Fernández-Hernando, C. Therapeutic silencing of microRNA‑33 inhibits the progression of atherosclerosis in Ldlr–/– mice—brief report. Arterioscler.Thromb.Vasc. Biol. 33, 1973–1977 (2013). 9. Eberlé, D. et al. Inducible Apoe gene repair in hypomorphic ApoE mice deficient in the low‑density lipoprotein receptor promotes atheroma stabilization with a human-like lipoprotein profile. Arterioscler.Thromb.Vasc. Biol. 33, 1759–1767 (2013). CARDIOVASCULAR IMAGING IN 2013 New era of evidence-based medicine with noninvasive imaging Puskar Pattanayak and David A. Bluemke In 2013, advances in noninvasive imaging methods pushed traditional boundaries in the detection, diagnosis, and functional assessment of coronary artery disease, atherosclerotic plaque, and myocardial function. We highlight five important studies that demonstrate how these developments are allowing medicine to become increasingly evidence‑based and personalized. Pattanayak, P. & Bluemke, D. A. Nat. Rev. Cardiol. 11, 74–76 (2014); published online 14 January 2014; doi:10.1038/nrcardio.2013.215 Diagnostic and interventional imaging meth­ods have frequently laid the foun- dation for advances in the diagnosis and treatment of cardiovascular diseases. Are engineering advancements in imaging scan- ners pushing evidence-based medicine into a new era? Dozens of high-impact cardiac imaging articles were published in 2013. In this Year in Review article, we discuss five of the most‑important studies on noninvasive imaging. Cardiac magnetic resonance (CMR) technology has added substantially to the assessment of myocardial scarring. After injection of the routinely used contrast agent gado­linium, bright areas of late enhance- ment indicate regions of myocardial scar tissue. The current dogma is that severe left ventricular wall thinning is indicative of a transmural myocardial infarction with no residual viable tissue. An end-diastolic wall thickness <5–6 mm has been presumed to be trans­mural myocardial scarring.1 How­ ever, a few case reports have suggested that areas of thinning might not be entirely com- posed of scar tissue. Therefore, Shah and colleagues used CMR to investigate 201 patients with coronary artery disease (CAD) and regional wall thinning.2 Overall, 18% of myocardial segments (<5.5 mm regions) were found to have limited (≤50% extent) or no scarring evident on late gadolinium enhancement. For patients with limited scar- ring, resolution of thinning occurred after revascularization, with a substantial increase in end-diastolic wall thickness. Contrary to current assumptions, this report suggests that patients with regional wall thinning might have viable tissue remaining. Therefore, viability testing should be considered to assess whether patients would benefit from revascular­ization.Furtherprospectivestudies are required to determine whether patient outcomes can be improved using CMR g­uidance for co­ronary revascularization. Coronary computed tomography angio­ graphy (CCTA) shows high sensitivity for the detection of coronary stenosis (Figure 1). © 2014 Macmillan Publishers Limited. All rights reserved
  • 12. KEY ADVANCES IN MEDICINE JANUARY 2014  |  9 CARDIOLOGY mean age was 14.6 years. The cumulative anthracycline dose was 224 mg/m2 for girls and 184 mg/m2 for boys. Abnormal left or right ventricular function (ejection fraction <45%) was detected in 18% and 27% of the participants, respectively. Subnormal left or right ventricular function (ejection frac- tion 45–55%) was seen in 61% and 53% of individuals, respectively. Left and right ven- tricular end-systolic and left ventricular end- diastolic volumes were increased, compared with reference values. None of the patients had CMR-detected focal myocardial fibrosis. This study was the first to show a high preva- lenceofbiventricularmyocardialdysfunction after fairly low anthracycline doses, in the absence of focal myocardial scarring, in sur- vivors of childhood cancer. The lifelong con- sequences of myocardial dysfunction from anthracycline therapy will require long-term follow-up to understand the i­mplications for these patients. Identification of ruptured or high-risk atherosclerotic plaque is not currently pos- sible using noninvasive imaging. In 2012, 18 F‑NaF was shown to be a marker of vas- cular calcification.9 A report from Joshi and colleagues now suggests that the radio­active tracer 18 F‑NaF might localize in unstable or ruptured plaque during PET–CT.10 This study included 40 patients with a myo- cardial infarction, 40 patients with stable angina, and 12 patients who had undergone carotid endarterectomy. Patients with myo- cardial infarction and stable angina under- went 18 F‑NaF and 18 F‑fluorodeoxyglucose (18 F‑FDG, which localizes in areas of inflam- mation) PET–CT, and ICA. In patients with stable angina, 18 F‑NaF uptake was com- pared with the results from intravascular ultrasonography. Furthermore, compari- sons were made between carotid specimen a b Figure 1 | Coronary CT angiogram of the heart. a | 3D representation. b | A heavily calcified right coronary artery showing moderate lumen narrowing. However, the technique tends to over­estimate stenosis severity. In some patients, only half of lesions identified using CCTA are actually confirmed as being physiologically relevant using invasive coronary angio­graphy (ICA).3 Fractional flow reserve measured using CT (FFRCT ) has emerged as a non­invasive method to determine whether stenoses observed using CCTA are haemodynamic­ ally relevant and actually causing ischaemia. FFRCT is calculated using computational fluid dynamic modelling. In 2013, Nakazato and colleaguesassessedtheperformanceofFFRCT to diagnose lesions of intermediate severity (30–69% stenosis as determined using CT).4 Patients underwent ICA and CCTA, and a total of 150 vessels of intermediate stenosis wereevaluated.FFRwasmeasuredusingICA with a pressure-monitoring guidewire placed distally to the stenosis. FFR and FFRCT ≤80% was considered ischaemic, and CT stenosis ≥50% was considered obstructive. FFRCT was found to have a high diagnostic perfor- mance compared with CT for the diagnosis of ischaemia—a twofold increase in sensitiv- ity (74% versus 34% per vessel) and a higher negative predictive value (90% versus 78% per vessel) was reported. FFRCT is one of several new applications of CCTA, with the aim of substantially improving noninvasive assessment of coronary anatomy. CCTA is likely to have an important future role in the noninvasive diagnosis of CAD. Although single-photon emission com- puted tomography (SPECT) is widely used in the detection of ischaemia, perfusion CMR has also been increasingly used for this purpose in clinical practice. CMR has been used on the basis of studies showing a strong diagnostic performance of CMR compared with ICA.5 Therefore, in the MR‑IMPACT II trial,6 Schwitter and col- leagues compared the diagnostic perform­ ance of CMR and SPECT for the detection of CAD. This prospective trial involved 425 patients at 33 centres. ICA was used as the reference standard. To define patients with CAD (that is, to define per­fusion defects), the presence of a ≥50% stenosis in more than one coronary artery >2 mm in diameter was used. A high perform­ance of perfusion CMR to detect CAD was demonstrated. The sensi- tivity of perfusion CMR (0.67) was superior to that of perfusion SPECT (0.59). However, the specificity of perfusion CMR (0.61) was inferior to that of perfusion SPECT (0.72). This study shows that perfusion CMR is a safe alternative to SPECT for detecting per- fusion abnormalities in patients with CAD, because CMR has the advantage over SPECT of not using i­onizing radiation. With increased survival from child­hood cancer, the need to assess the cardiotoxic effects of chemotherapeutic agents has grown, particularly given that increased myocardial fibrosis has been detected in endo­myocardial biopsies of survivors. Further­­more, a cumulative incidence of congestive heart failure >7.5% at 30 years in patients with a dose of anthracycline ≥250 mg/m2 has been reported.7 Therefore, Ylanen and colleagues used CMR to evalu- ate the prevalence of left and right ventricu- lar dysfunction and signs of focal fibrosis among long-term survivors of childhood cancer who had been exposed to anthra- cycline.8 The cohort comprised 62 patients who were in remission from cancer, and the Key advances ■■ Patients with thin myocardial walls, previously defined as scar tissue, might have myocardium that is viable and recovers some function and wall thickness after therapy2 ■■ CT fractional flow reserve (FFRCT ) is one of several new applications of coronary CT angiography (CCTA) that aim to substantially improve the noninvasive assessment of coronary stenosis4 ■■ Perfusion cardiac magnetic resonance (CMR) is a safe and sometimes superior alternative to single-photon emission computed tomography for detecting perfusion abnormalities in coronary artery disease6 ■■ CMR imaging detects a high prevalence of myocardial dysfunction after a fairly low dose of anthracycline chemotherapy in survivors of childhood cancer8 ■■ 18 F‑NaF uptake identifies ruptured and high-risk atherosclerotic plaques in symptomatic patients with coronary or carotid artery disease10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 13. 10  |  JANUARY 2014 www.nature.com/reviews CARDIOLOGY histology and 18 F‑NaF uptake. The highest coronary 18 F‑NaF uptake was seen in the culprit plaque in 93% of patients with myo- cardial infarction. By contrast, conventional 18 F‑FDG PET–CT did not accurately identify high-risk plaques. A total of 45% of patients with stable angina had plaques with focal 18 F‑NaF uptake. These plaques were asso­ ciated with more high-risk features on intra- vascular ultrasonography than those without 18 F‑NaF uptake. In the carotid artery, the site of plaque rupture showed marked 18 F‑NaF uptake. These preliminary findings suggest a new, high-sensitivity imaging technique that might help to distinguish between high- risk plaques and stable calcium deposits in mature plaques. Prospective studies will be required to investigate whether 18 F‑NaF PET can be used to predict cardiovascular events. In summary, developments in non­invasive imaging methods have been rapid and p­rom­ ise to change the future of diagnostic cardio­ logy. In 2013, imaging methods pushed traditional boundaries in the understanding of CAD, atherosclerotic plaque development and diagnosis, as well as myocardial function. Given the attractiveness of noninvasive tech- niquestoanincreasingnumberofresearchers in the field, 2014 promises to be yet another exciting year in cardiovascular imaging. National Institutes of Health Clinical Center, National Institute of Biomedical Imaging and Engineering, 10 Center Drive, Bethesda, MD 20892, USA (P. Pattanayak, D. A. Bluemke). Correspondence to: D. A. Bluemke bluemked@nih.gov Acknowledgements The views and opinions of the authors do not necessarily state or reflect those of the US Government, and they may not be used for advertising or product endorsement purposes. Competing interests The authors declare no competing interests. 1. Schmidt, M. et al. F‑18‑FDG uptake is a reliable predictor of functional recovery of akinetic but viable infarct regions as defined by magnetic resonance imaging before and after revascularisation. Magn. Reson. Imaging 22, 229–236 (2004). 2. Shah, D. J. et al. Prevalence of regional myocardial thinning and relationship with myocardial scarring in patients with coronary artery disease. JAMA 309, 909–918 (2013). 3. Meijboom, W. B., Van Mieghem, C. A. & van Pelt, N. Comprehensive assessment of coronary artery stenoses: computed tomography coronary angiography versus conventional coronary angiography and correlation with fractional flow reserve in patients with stable angina. J.Am. Coll. Cardiol. 52, 636–643 (2008). 4. Nakazato, R. et al. Noninvasive fractional flow reserve derived from computed tomography angiography for lesions of intermediate stenosis severity: results from the DeFACTO study. Circ. Cadiovasc. Imaging 6, 881–889 (2013). 5. Plein, S. et al. High spatial resolution myocardial perfusion cardiac magnetic resonance for the detection of coronary artery disease. Eur. Heart J. 29, 2148–2155 (2008). 6. Schwitter, J. et al. MR‑IMPACT II: magnetic resonance imaging for myocardial perfusion assessment in coronary artery disease trial: perfusion cardiac magnetic resonance vs single photon emission compute tomography for the detection of coronary artery disease: a comparative multicentre, multivendor trial. Eur. Heart J. 34, 775–781 (2013). 7. Mulrooney, D. A. et al. Cardiac outcomes in a cohort of adult survivors of childhood and adolescent cancer: retrospective analysis of the childhood cancer survivor study cohort. BMJ 339, b4606 (2009). 8. Ylanen, K. et al. Cardiac magnetic resonance imaging in the evaluation of the late effects of anthracyclines among long term survivors of childhood cancer. J.Am. Coll. Cardiol. 61, 1539–1547 (2013). 9. Dweck, M. R. et al. Coronary arterial 18 F‑fluoride uptake: a novel marker of plaque biology. J.Am. Coll. Cardiol. 59, 1539–1548 (2012). 10. Joshi, N. V. et al. 18 F‑fluoride positron emission tomography for identification of ruptured and high-risk coronary atherosclerotic plaques: a prospective clinical trial. Lancet http:// dx.doi.org/10.1016/S0140-6736(13)61754-7. © 2014 Macmillan Publishers Limited. All rights reserved
  • 14. Editors’ picks of the year Myofibroblast-mediated mechanisms of pathological remodelling of the heart Karl T. Weber, Yao Sun, Syamal K. Bhattacharya, Robert A. Ahokas and Ivan C. Gerling In the diseased heart, cardiomyocytes undergo necrotic cell death. A healing response results in myofibroblast production of collagen and other matrix molecules, which initially serve to preserve the structural integrity of the myocardium. However, myofibroblast dispersion fails to occur in many cardiac diseases, and perpetual matrix formation leads to adverse remodelling of the heart. doi:10.1038/nrcardio.2012.158 Assessment and management of blood-pressure variability Gianfranco Parati, Juan E. Ochoa, Carolina Lombardi and Grzegorz Bilo Blood pressure is characterized by short-term and long-term fluctuations, which are the result of complex interactions between environmental and behavioural factors and, additionally, cardiovascular regulatory mechanisms. Increased blood pressure variability leads to cardiac, vascular, and renal damage, and is associated with an increased risk of cardiovascular morbidity and mortality. doi:10.1038/nrcardio.2013.1 Targeting the renin–angiotensin–aldosterone system in heart failure Chim C. Lang and Allan D. Struthers The renin–angiotensin–aldosterone system is well established as a therapeutic target in patients with heart failure. Professors Lang and Struthers discuss new indications for existing drugs in patients who have heart failure with or without reduced ejection fraction. They also review novel ways of targeting the renin– angiotensin–aldosterone system in these patients. doi:10.1038/nrcardio.2012.196 The biology behind the atherothrombotic effects of cigarette smoke Adam Csordas and David Bernhard Cigarette smoke is an aerosol that exerts multiple atherothrombotic effects on smokers and the individuals around them. In this Review, Csordas and Bernhard describe the current knowledge of the mechanisms through which cigarette smoke affects all stages of plaque formation and development, as well as pathological thrombus formation. doi:10.1038/nrcardio.2013.8 The roles of senescence and telomere shortening in cardiovascular disease Frej Fyhrquist, Outi Saijonmaa and Timo Strandberg Telomere shortening, and various other endogenous and environmental factors, can drive cells into senescence, which is involved in the complex process of biological ageing. Fyhrquist and colleagues discuss the associations between cardiovascular risk factors and telomere shortening, and whether cellular senescence has a causal role in conditions such as atherosclerosis, heart failure, and hypertension. doi:10.1038/nrcardio.2013.30 Renal sympathetic denervation: applications in hypertension and beyond Michael Böhm, Dominik Linz, Daniel Urban, Felix Mahfoud and Christian Ukena Increased sympathetic activity is associated with a number of diseases, including resistant hypertension. Renal denervation is increasingly being used as a treatment for patients with resistant hypertension in some parts of the world. The pathophysiology of this technique, its use in treating patients with hypertension, and its potential in the treatment of patients with other conditions are discussed in this Review. doi:10.1038/nrcardio.2013.89 Update on atrial fibrillation catheter ablation technologies and techniques Jane Dewire and Hugh Calkins Atrial fibrillation is one of the most common heart arrhythmias. Dewire and Calkins discuss the development and role of catheter ablation to electrically isolate the pulmonary veins in patients with paroxysmal, persistent, or longstanding persistent atrial fibrillation. They go on to highlight novel tools that improve the safety, efficacy, and precision of ablation techniques. doi:10.1038/nrcardio.2013.121 Optimal revascularization for complex coronary artery disease Javaid Iqbal, Patrick W. Serruys and David P. Taggart Patients with coronary artery disease who do not respond to optimal medical therapy are candidates for revascularization. The choice of revascularization technique is dependent on a patient’s overall medical state. Iqbal and colleagues review the evidence for coronary artery bypass graft surgery versus percutaneous coronary intervention as the optimal revascularization method in various groups of patients with complex coronary artery disease. doi:10.1038/nrcardio.2013.138 Mechanisms and management of TAVR-related complications Amir-Ali Fassa, Dominique Himbert and Alec Vahanian Transcatheter aortic valve replacement is an effective treatment for patients with severe aortic stenosis who are not suitable candidates for surgery. However, serious complications can occur. In this Review, Alec Vahanian and colleagues describe TAVR-related complications, the mechanisms that cause these events, and methods of preventing them. doi:10.1038/nrcardio.2013.156 Silent cerebral infarcts associated with cardiac disease and procedures Mariëlla E. C. Hassell, Robin Nijveldt, Yvo B. W. Roos, Charles B. L. Majoie, Martial Hamon, Jan J. Piek and Ronak Delewi Silent cerebral infarcts frequently occur in association with cardiovascular disease and cardiac interventional procedures, but their prognostic importance is unknown. In this Review, Hassell and colleagues assess the incidence and detection of silent cerebral infarcts, and their possible association with adverse neurological outcomes, such as stroke, depression, cognitive decline, and dementia. doi:10.1038/nrcardio.2013.162 February 2014 volume 11 no. 2 www.nature.com/reviews REFRACTORY ANGINA Treatment options for patients not suitable for revascularization Endovascular repair of AAAs Current and future strategies CARDIOLOGY An official publication of nrcardio_OFC_FEB14.indd 1 09/01/2014 14:36 * * * * * * * * * * A selection of articles published during 2013 in Nature Reviews Cardiology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Cardiology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 15. KEY ADVANCES IN MEDICINE JANUARY 2014  |  11 CLINICAL ONCOLOGY LUNG CANCER IN 2013 Refining standard practice and admitting uncertainty Stephen V. Liu and Giuseppe Giaccone In 2013, the treatment of several NSCLC subtypes was refined. PROFILE‑1007 and LUX-Lung 3 confirmed that targeted therapy was superior to chemotherapy, whereas NCIC BR19 and PointBreak failed to show superiority of adjuvant gefitinib and combined maintenance therapy, respectively. These studies reinforced some practices and discouraged others, underscoring the need for new prospective studies. Liu, S. V. & Giaccone, G. Nat. Rev. Clin. Oncol. 11, 69–70 (2014); published online 21 January 2014; doi:10.1038/nrclinonc.2013.251 The extensive molecular characterization of non-small-cell lung cancer (NSCLC) over the past decade has led to the identification of unique subsets of NSCLC that benefit from targeted therapies. NSCLC tumours that harbour activating mutations in EGFR or rearrange­ments in the anaplastic lym- phoma kinase (ALK) gene are routinely and effectively treated with tyrosine kinase inhibitors (TKI) such as erlotinib and crizo- tinib, respectively. Several important studies reported in 2013 have provided valuable insight into the evolving treatment para- digms of NSCLC, p­articularly with regard to targeted therapies (Table 1). Rearrangements in ALK are present in approximately 5% of adenocarcinoma of the lung and the small molecule TKI crizo- tinib has emerged as a standard treatment in this setting.1 Crizotinib was granted accelerated approval by the FDA in 2011 for patients with ALK-positive NSCLC with no restrictions on line of therapy.1 Crizotinib also received conditional approval in 2012 from the European Medicines Agency. These approvals were based on two, single- arm studies that demonstrated impressive response rates in patients with ALK-positive NSCLC.1,2 Approval was contingent on a formal comparison between crizotinib and chemotherapy in these patients; the phase III PROFILE‑1007 trial, published in 2013, pro- vides that comparison. This open-label trial randomly assigned 347 patients with ALK‑ positive NSCLC previously treated with one platinum-based chemotherapy regimen to receive crizotinib or standard pemetrex­ed or docetaxel-based chemotherapy.3 Inthis study, crizotinib was more effective than chemo- therapy. Patients treated with crizotinib had a median progression-free survival (PFS) of 7.7 months compared with 3.0 months with chemotherapy (HR 0.49; 95% CI 0.37–0.64, P <0.001). There was no significant differ- ence in overall survival in the interim analy- sis, likely due to crossover, as 64% of patients who were assigned to receive chemotherapy subsequently received crizotinib. Patients in the crizotinib arm also had a higher response rate (65% versus 20%) and a greater improve- ment in quality of life. Although crizotinib had already received conditional approval in this setting, the random­ized, prospective PROFILE‑1007 trial provides important information c­onfirming what has become common practice.3 A similar trial conducted in patients with EGFR-mutant NSCLC reinforced this theme. The phase III LUX-Lung 3 trial explored the activity of afatinib, an inhibitor of the EGFR family that targets EGFR, HER2 and HER4.4 LUX-Lung 3 was the largest random- ized trial for patients with advanced-stage EGFR-mutant NSCLC; this study randomly assigned 345 patients with advanced-stage adenocarcinoma in a 2:1 ratio to receive either afatinib or chemotherapy with cispla- tin plus pemetrexed. As seen in similar trials featuring erlotinib and gefitinib, the targeted agent was superior to chemotherapy. Median PFS, the primary end point, with afatinib was 11.1 months compared with 6.9 months with chemotherapy (HR 0.58; 95% CI 0.43–0.78, P = 0.001).Therewasnosignificantdifference in overall survival between these arms (HR 1.12; 95% CI 0.73–1.73, P = 0.60) and again, crossover might be responsible for this lack of superiority in survival, as 65% of patients in the chemotherapy arm received EGFR tar- geted therapy at disease progression. Afatinib was associated with greater improvement in dyspnoea and cough, as well as better global healthstatususingtheEORTCQualityofLife questionnaire C30.5 In addition, this study also provided prospective data on the activity ofafatinibinpatientsharbouringuncommon EGFR alterations, including L861Q, G719X andS768I.6 Despitethesefindings,theoptimal use of afatinib is not readily apparent: will it Table 1 | Trials in non-small-cell lung cancer in 2013 Trial Patients Treatment Outcome Comments PROFILE‑10073 Pretreated ALK‑positive Crizotinib Cis + Pem PFS HR 0.49 (95% CI 0.37–0.64) P <0.001 No OS benefit possibly due to 64% crossover from Cis + Pem to crizotinib LUX-Lung 34 Untreated EGFR-mutant Afatinib Cis + Pem PFS HR 0.58 (95% CI 0.43–0.78) P = 0.001 No OS benefit possibly due to 65% crossover from Cis + Pem to EGFR targeted therapy NCIC CTG BR197 Resected stage IB–IIIA, unselected Gefitinib Placebo DFS HR 1.84 (95% CI 0.44–7.73) P = 0.395 Analysis of EGFR-mutant subset (n = 15) failed to show benefit PointBreak10 Untreated stage IIIB/IV PemCBev PacCBev OS HR 1.00 (95% CI 0.86–1.16) P = 0.949 PFS benefit with PemCBev did not translate to OS benefit Abbreviations: Cis, cisplatin; DFS, disease-free survival; OS, overall survival; PacCBev, paclitaxel plus carboplatin plus bevacizumab with bevacizumab maintenance; Pem, pemetrexed; PemCBev, pemetrexed plus carboplatin plus bevacizumab with pemetrexed plus bevacizumab maintenance; PFS, progression-free survival. © 2014 Macmillan Publishers Limited. All rights reserved
  • 16. 12  |  JANUARY 2014 www.nature.com/reviews CLINICAL ONCOLOGY displace erlotinib and gefitinib in the front- line setting or will it be reserved for patients withacquiredresistancetotheseexisting,and potentially better tolerated, agents? Now that several well-designed studies have shown EGFR targeted agents are more effective than chemo­therapy in the first-line setting, hopefully LUX-Lung 3 marks the end of this study design and the use of approved EGFR targeted agents in the comparator arm should now become stand­ard. It is also worth reinfor­cingtheneedfortheseinitialstudies,as although treatment of ALK-positive NSCLC is very similar to EGFR-mutant NSCLC, the optimal treatment strategy may be different for other putative driver mutations. We will await results from ongoing studies interrogat- ing different subtypes, including those with a­berrations in ROS1, RET, BRAF and others. Targeted therapy in early-stage NSCLC remains highly controversial, in large part owing to the results of the NCIC CTG BR19 study of gefitinib versus placebo in resected NSCLC.7 This trial was designed to ran- domly assign 1,242 unselected patients with completely resected stage IB–IIIA NSCLC to receive either gefitinib or placebo for 2 years. Thistrialwasclosedprematurelyin2005after 503patientswereenrolled,basedontwoother negative studies with gefitinib.8,9 This left the NCIC CTG BR19 study under­powered for its final analysis. In addition, standard use of adjuvant chemotherapy emerged after this trial had launched and only 17% of patients received this proven treatment. With these shortcomings in mind, use of gefitinib did not improve disease-free survival (DFS) or overall survival in the unselected popula- tion. Somewhat surprisingly, gefitinib also did not improve either DFS (HR 1.84, 95% CI 0.44–7.73, P = 0.395) or overall survival (HR 3.16, 95% CI 0.61–16.45, P = 0.15) in the EGFR-mutant subset (n = 15). It is difficult to make meaningful conclusions on the basis of this study and targeted therapy may still prove effective in early-stage NSCLC. Given these results, however, use of EGFR targeted agents in the adjuvant setting should be in the context of a clinical trial, such as the recently completed RADIANT study. Another major advance over the past few years has been the emergence of main- tenance therapy in NSCLC. The standard chemotherapy strategy for NSCLC had been 4–6 cycles of platinum-doublet therapy fol- lowed by observation. With the development of better tolerated agents and improved sup- portive care,dataemerged supporting the use of several agents in the maintenance setting, buttheoptimalmaintenancestrategyremains unclear. In 2013, the randomized, phase III PointBreak trial10 compared two popular maintenance strategies in patients with advanced-stage, nonsquamous NSCLC. In this study, 939 patients were randomly assigned to receive carboplatin, paclitaxel and bevacizumab followed by bevacizumab maintenance, as used in the ECOG 4599 study,orcarboplatin,pemetrexedand bevaci­ zumab followed by bevacizumab and pem­ etrexed maintenance. This trial showed no survival advantage with the additional maintenance agent; median overall survival in the group assigned to receive paclitaxel was 13.4 months compared to 12.6 months with the pemetrexed strategy (P = 0.949). There was a superior PFS with pemetrexed (6.0 monthsversus5.6 months,P = 0.012)and this was more pronounced in the subset of patients who completed initial therapy and successfully reached the main­tenance phase (8.6 months versus 6.9 months), but this did not translate into a benefit in overall sur- vival. The toxic effects were different in the two arms, with more anaemia, thrombocyto­ penia and fatigue seen in the pemetrexed arm and more neutro­penia, febrile neutropenia, neuro­pathy and alopecia in the paclitaxel arm. The PointBreak study did not establish a clear standard in the maintenance setting and that is still an unanswered question. The ongoing three-armed ECOG 5508 trial—in which patients receiving induction with carbo­platin, paclitaxel and bevacizumab will be randomly assigned to receive maintenance withbevacizumab,pem­etrexedorboth—may offer further insight. The underlying theme, however, is that the benefit of cytotoxic therapy is not necessarily exhausted after 4–6 cycles, p­rovided toxicity can be managed. Genomic-based targeted therapy repre- sents the most important paradigm in the treatment of advanced-stage lung cancer. Although the use of crizotinib and afatinib in molecularly defined populations was supported by the PROFILE‑1007 and LUX- Lung 3 studies, the adjuvant NCIC CTG BR19 study warns against early adoption and reminds us of the need for prospec- tive studies. Similarly, the PointBreak study serves as a reminder that more is not neces­ sarily better. Given the developments over the past year, we expect the coming years to further optimize induction, maintenance and adjuvant therapy for these and other subtypes of NSCLC. Importantly, strategies designed to delay or overcome acquired resistance to therapy will emerge in the near future. Lombardi Comprehensive Cancer Center, Georgetown University, 3800 Reservoir Road NW,Washington, DC 20007, USA (S. V. Liu, G. Giaccone). Correspondence to: G. Giaccone giacconeg@mail.nih.gov Competing interests The authors declare no competing interests. 1. Camidge, D. R. et al. Activity and safety of crizotinib in patients with ALK-positive non‑small‑ cell lung cancer: updated results from a phase 1 study. Lancet Oncol. 13, 1011–1019 (2012). 2. Kim, D. W. et al. Results of a global phase II study with crizotinib in advanced ALK-positive non-small cell lung cancer (NSCLC) [abstract]. J. Clin. Oncol. 30 (Suppl. 15), a7533 (2012). 3. Shaw, A. T. et al. Crizotinib versus chemotherapy in advanced ALK-positive lung cancer. N. Engl. J. Med. 368, 2385–2394 (2013). 4. Sequist, L. V. et al. Phase III study of afatinib or cisplatin plus pemetrexed in patients with metastatic lung adenocarcinoma with EGFR mutations. J. Clin. Oncol. 31, 3327–3334 (2013). 5. Yang, J. C. et al. Symptom control and quality of life in LUX-Lung 3: a phase III study of afatinib or cisplatin/pemetrexed in patients with advanced lung adenocarcinoma with EGFR mutations. J. Clin. Oncol. 31, 3342–3350 (2013). 6. Yang, J. C. et al. Activity of afatinib in uncommon epidermal growth factor receptor (EGFR) mutations: findings from three prospective trials of afatinib in EGFR mutation-positive lung cancer [abstract]. World Conference on Lung Cancer, 1114, 003.05 (Sidney, Australia, 2013). 7. Goss, G. D. et al. Gefitinib versus placebo in completely resected non‑small‑cell lung cancer: results of the NCIC CTG BR19 study. J. Clin. Oncol. 31, 3320–3326 (2013). 8. Kelly, K. et al. Phase III trial of maintenance gefitinib or placebo after concurrent chemoradiotherapy and docetaxel consolidation in inoperable stage III non‑small‑cell lung cancer: SWOG S0023. J. Clin. Oncol. 26, 2450–2456 (2008). 9. Thatcher, N. et al. Gefitinib plus best supportive care in previously treated patients with refractory advanced non‑small‑cell lung cancer: results from a randomised, placebo-controlled, multicentre study (Iressa Survival Evaluation in Lung Cancer). Lancet 366, 1527–1537 (2005). 10. Patel, J. D. et al. PointBreak: a randomized phase III study of pemetrexed plus carboplatin and bevacizumab followed by maintenance pemetrexed and bevacizumab versus paclitaxel plus carboplatin and bevacizumab followed by maintenance bevacizumab in patients with stage IIIb or IV nonsquamous non‑small‑cell lung cancer. J. Clin. Oncol. 31, 4349–4357 (2013). Key advances ■■ In advanced-stage lung cancer, targeted therapy continues to be a more effective option than chemotherapy, specifically, crizotinib in ALK-positive lung cancer3 and afatinib in EGFR-mutant lung cancer4 ■■ In the adjuvant setting, the role of targeted therapy remains unclear7 ■■ Combination maintenance therapy with pemetrexed plus bevacizumab after induction with pemetrexed-based chemotherapy was not superior to bevacizumab maintenance alone after induction with a paclitaxel-based regimen10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 17. KEY ADVANCES IN MEDICINE JANUARY 2014  |  13 CLINICAL ONCOLOGY BREAST CANCER IN 2013 Genomics, drug approval, and optimal treatment duration Adrian V. Lee and Nancy E. Davidson 2013 saw much progress in breast cancer research. Advances in high- throughput technologies continue to refine our knowledge of the molecular biology of breast cancer, and are beginning to give insight into cancer evolution, drug resistance, and how to deploy precision therapeutics. Lee, A. V. & Davidson, N. E. Nat. Rev. Clin. Oncol. 11, 71–72 (2014); published online 14 January 2014; doi:10.1038/nrclinonc.2013.250 The tremendous molecular diversity in cancers, both between patients and within a single patient, challenges standard basic research techniques and traditional drug design and testing. Breast cancer is con- sidered the most common cause of cancer deaths among women worldwide. It is a clinically and biologically heterogeneous disease that will require new approaches for the translation of precision medicine into new treatments tailored to the biology of the specific tumour. In one comprehensive genomic report, TheCancerGenomeAtlas(TCGA)research- ers performed an analysis to identify somatic point mutations and small insertions or del­ etions in 12 cancer types. This study showed that breast cancer has one of the lowest muta- tion rates in solid tumours, with an average of ~3,000 somatic mutations per tumour (range ~90–60,000).1 Breast cancers were enriched with mutations in TP53, PIK3CA, GATA3, MAP3K1, CDH1, and MLL3. In a separate study, Alexandrov and col- leagues analysed somatic mutations from > 7,000 tumours (representing 30 different classes) and found that the mutation rate in breast cancer samples was strikingly similar to that observed in the TCGA pan-cancer analysis.2 Breast cancers showed foci of h­ypermutation—termed kataegis—that were associated with large structural rearrange- ments. Specific mutation signatures were strongly associated with tumours harbouring loss of BRCA1 or BRCA2. The researchers also identified a unique type of base pair mutation (C>T and C>G at TCN trinucleo- tides) that is consistent with aberrant activity of endogenous APOBECs proteins, cytidine deaminases that normally convert cytidine to uracil. Several other studies in 2013 revealed a role for the overexpression of APOBEC family members in breast and other cancers, suggest­ing that the APOBEC-mediated cyti- dine deami­nation might represent a general mechanism to generate mutations during tumorigenesis. Overall, published reports in the past 2–3 years have comprehensively identified several somatic point mutations and small insertions or d­eletions in primary breast tumours. Breast cancer genomics remains an evolv- ing story, as most large sequencing studies have so far focused on primary breast cancer. Furthermore, recent reports of sequencing in metastases have described mutations that are absent or present at very low frequencies in primary tumours (such as in rare subclones), supporting the need for further mutational analysis of metastases. Indeed, one of the greatest surprises in breast cancer genetics in 2013 was the identification of mutations in the gene encoding the oestrogen recep- tor (ER, ESR1) in breast cancer metastases. As ER is a central driver and a primary target in breast cancer, most researchers had sur- mised that it must be mutated at least in some endocrine-resistant tumours. However, very few mutations have been identified des­ pite intensive efforts. For example, TCGA identified somatic mutations in ESR1 in only two of 825 primary breast cancers (0.2%). The genomic landscape changed dramati- cally when the analysis was shifted from primary tumours to advanced-stage and hormone-resistant disease. In a Herculean effort designed to sequence and character- ize patient-derived xenografts, Ellis and col- leagues identified ESR1 somatic mutations in advanced-stage breast cancer samples from patients refractory to antihormonal therapy.3 These findings were substantiated in two subsequent studies that reported the identification of ESR1 somatic mutations in six out of 11 (55%) and 14 of 80 (17.5%) patients with ER‑positive metastatic breast cancer, respectively.4,5 Importantly, these mutations were found almost exclusively in advanced-stage ER‑positive breast cancers, and they emerged after patients were treated with an aromatase inhibitor rather than an antioestrogen. The somatic mutations clus- tered in the ligand binding domain of the ER; structure–function studies showed that these mutations resulted in conformational changes to the ER, leading to its constitutive activation. This ligand-independent activ- ity caused complete resistance to aromatase inhibitors and partial resistance to selective oestrogen-receptor modulators and degrad- ers. Together, these findings open up a new avenue in the development of therapies for ER‑positive advanced-stage breast cancer by investigating the mechanism of hormone action and suggest the use of inhibitors that specifically target the mutated ER. Sequencing of distinct tumour regions, and single cancer cells, has revealed tremen­ dous intratumour heterogeneity. TCGA and other large genomic projects have struggled to address the degree of intra­ tumour hetero­geneity. Moreover, deter- mining the extent and clinical significance of such hetero­geneity is hampered by the difficulty in obtaining repeated tissue biop­sies. An attractive alternative is the NPG © 2014 Macmillan Publishers Limited. All rights reserved
  • 18. 14  |  JANUARY 2014 www.nature.com/reviews CLINICAL ONCOLOGY exami­nation of circulating cancer DNA in plasma (circulating-free DNA or cfDNA), the so-called liquid biopsy. The year 2013 saw two reports on longitudinal analysis of whole-exome and whole-genome sequenc- ing of cfDNA in patients with breast cancer. Whole-exome sequencing of cfDNA col- lected over 1–2 years from patients with advanced-stage breast cancer showed that mutations detected in liquid biopsies arose or increased in frequency in conjunction with the development of clinical therapeu- tic resistance.6 In one patient, treatment with tamoxifen and trastuzumab (an anti- HER2 monoclonal antibody) was followed by an increase in the truncation of MED1 (mediator complex subunit 1) gene product, an ER co-activator known to be involved in tamoxifen resistance. Subsequent treatment of this patient with lapatinib and capecita­ bine was followed by an increase in a splic- ing mutation in GAS6, encoding the ligand for tyrosine kinase receptor AXL, which has been shown to cause resistance to lapatinib.6 Moreover, Dawson et al.7 describe the use of whole-exome and whole-genome sequenc- ing of cfDNA to design patient-specific assays for longitudinal monitoring. cfDNA was detected in 29 out of 30 (97%) patients with advanced-stage breast cancer, whereas elevated levels of CA15‑3 antigen and cir- culating tumour cells were only detected in 78% and 87% of the patients, respectively. Importantly, an increase in cfDNA was detected months before confirmation of dis­ ease progression by CT scan. These studies highlight the potential of using cfDNA to monitor disease burden and progression, and also the ability to identify possible targets to treat the disease and prevent the emergence of drug resistance. The use of massively parallel sequenc- ing to personalize genomic-directed breast cancer therapy is becoming a reality. However, the number of approved ‘tar- geted’ drugs remains low, and the path for their clinical development and testing is unacceptably long. A fast-track path for approval of new therapeutics is needed to tackle the diverse array of somatic muta- tions found in breast cancer. In May 2012, the FDA provided guidelines for the use of pathological complete res­ponse (pCR) as an end point to support the develop­ment and accelerated approval of new agents in the setting of neoadjuvant treatment of high-risk early stage breast cancer. In 2013, pertuzumab (Genentech, USA) was the first agent to benefit from the new guidance and received approval as a neo­adjuvant treat- ment for patients with HER2-positive early stage breast cancer. Finally, in 2013, the results of four large clinical trials designed to optimize the use of active targeted agents were reported. The ATLAS trial compared 10 years versus 5 years of tamoxifen treat- ment in 12,894 women with early stage breast cancer,8 and concluded that con- tinuing tamoxifen to 10 years rather than stopping at 5 years produced a further reduction in recurrence and mortality. The greatest effect of extended tamoxifen treat- ment was observed from year 10 to year 15, with a recurrence rate ratio of 0.75 and a mortality rate ratio of 0.71. These data were confirmed by the preliminary results of the aTTom trial. How­ever, although these findings—combined with previous reports of extended aromatase inhibitor use after tamoxifen—highlight the value of extended adjuvant hormone treatment, this model does not hold true for all adjuvant thera­ pies. Indeed, the PHARE trial showed that 6 months of adjuvant trastuzumab cannot be regarded as a substitute for the current stand­ard treatment of 1 year of trastu- zumab.9 The HERA trial results demon­ strated that 2 years of adjuvant trastu­zumab treatment was not more beneficial in redu­ cing recurrence of HER2-positive breast cancer than 1 year of treatment.10 The dif­ fer­ence between optimal length of adjuvant tamoxifen and trastuzumab therapy could have several explanations, but one might be the relative indolence of ER‑positive dis­ease in which endocrine therapies, such as tamo­xifen, act to control the dor- mancy of micro­metastases. These findings suggest that targeted t­herapies will require extensive optimization. We foresee that the coming years will continue to improve our knowledge of breast cancer. New techniques that include deep sequenc­ing and digital multiplexed patho­logy are enabling unprecedented investigations into the underpinnings of breast cancer that will likely have a major impact on t­reatment and prevention. Departments of Pharmacology and Chemical Biology, Human Genetics, and Medicine, Women’s Cancer Research Center, Magee–Womens Research Institute, University of Pittsburgh, 204 Craft Avenue, Pittsburgh, PA 15238, USA (A. V. Lee). University of Pittsburgh Cancer Institute and University of Pittsburgh Medical Center Cancer Center, 5150 Center Avenue, Pittsburgh, PA 15232, USA (N. E. Davidson). Correspondence to: N. E. Davidson davidsonne@upmc.edu Acknowledgements The work by the authors is supported in part by the National Cancer Institute of the NIH awards P30CA047904 (N. E. Davidson) and R01CA94118 (A. V. Lee). The content is solely the responsibility of the authors and does not necessarily represent the official views of the NIH. The authors are also supported by funding through the Breast Cancer Research Foundation (N. E. Davidson and A. V. Lee), Susan G. Komen for the Cure (A. V. Lee), and the Pennsylvania Department of Health (N. E. Davidson and A. V. Lee). The Pennsylvania Department of Health specifically disclaims responsibility for any analyses, interpretations, or conclusions. Competing interests The authors declare no competing interests. 1. Kandoth, C. et al. Mutational landscape and significance across 12 major cancer types. Nature 502, 333–339 (2013). 2. Alexandrov, L. B. et al. Signatures of mutational processes in human cancer. Nature 500, 415–421 (2013). 3. Li, S. et al. Endocrine‑therapy‑resistant ESR1 variants revealed by genomic characterization of breast‑cancer‑derived xenografts. Cell Rep. 4, 1116–1130 (2013). 4. Robinson, D. R. et al. Activating ESR1 mutations in hormone-resistant metastatic breast cancer. Nat. Genet. 45, 1446–1551 (2013). 5. Toy, W. et al. ESR1 ligand-binding domain mutations in hormone-resistant breast cancer. Nat. Genet. 45, 1439–1445 (2013). 6. Murtaza, M. et al. Non-invasive analysis of acquired resistance to cancer therapy by sequencing of plasma DNA. Nature 497, 108–112 (2013). 7. Dawson, S. J. et al. Analysis of circulating tumor DNA to monitor metastatic breast cancer. N. Engl. J. Med. 368, 1199–1209 (2013). 8. Davies, C. et al. Long-term effects of continuing adjuvant tamoxifen to 10 years versus stopping at 5 years after diagnosis of oestrogen receptor- positive breast cancer: ATLAS, a randomised trial. Lancet 381, 805–816 (2013). 9. Pivot, X. et al. 6 Months versus 12 months of adjuvant trastuzumab for patients with HER2- positive early breast cancer (PHARE): a randomised phase 3 trial. Lancet Oncol. 14, 741–748 (2013). 10. Goldhirsch, A. et al. 2 Years versus 1 year of adjuvant trastuzumab for HER2-positive breast cancer (HERA): an open-label, randomised controlled trial. Lancet 382, 1021–1028 (2013). Key advances ■■ The oestrogen receptor gene (ESR1) is mutated in several hormone-resistant advanced-stage breast cancers, which have altered activity and might represent novel therapeutic targets4,5 ■■ Breast cancer mutations detected in circulating-free DNA by whole-exome and whole-genome sequencing change with therapeutic resistance and can reflect disease progression6,7 ■■ Extended adjuvant hormone therapy is more efficacious than short-term therapy,8 but extended adjuvant trastuzumab therapy is not10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 19. KEY ADVANCES IN MEDICINE JANUARY 2014  |  15 CLINICAL ONCOLOGY LIVER CANCER IN 2013 Mutational landscape of HCC —the end of the beginning Augusto Villanueva and Josep M. Llovet Next-generation sequencing analysis and characterization of the microenvironment ‘field-effect’ that promotes hepatocellular carcinoma (HCC) development has revealed critical players and potential targets for chemoprevention. A biomarker-based drug development strategy is needed to improve future HCC clinical trials and therapies. Villanueva, A. & Llovet, J. M. Nat. Rev. Clin. Oncol. 11, 73–74 (2014); published online 7 January 2014; doi:10.1038/nrclinonc.2013.243 in JAK1 in 9% of hepatitis B virus (HBV)- related HCC.4 JAK1, a member of the Janus tyrosine kinase family, has a role in immunity, cell growth and differentiation, mostly via STAT signalling, and mutations in JAK1 have been associated with some types of leukaemia. Functional validation of these HCC-related JAK1 mutations in experi­mental models suggested that JAK1 inhibition represents an attractive new therapeutic target. It was also clear that genes such as EGFR, BRAF, PIK3CA or KRAS, commonly mutated in other solid tumours, are rarely mutated in HCC (<5% of cases; Table 1).2–4 Several geno­mic studies have contributed to the identifi­cation of molecular subclasses of HCC. As predicted, recurring mutations in HCC fall within certain gene-expression patterns.5 For example, CTNNB1 mutations are signifi- cantly enriched in patients within the WNT molecular subclass as defined by using u­nsupervised microarray expression data.5 In 2013, mutations in the promoter of the telomerase reverse-transcriptase (TERT) gene have emerged as the most prevalent somatic mutation affecting 60% of HCC cases,6 an important finding that has impacted the landscape of genetic altera- tions in HCC. These mutations created a potential binding site for the E‑twenty six (ETS) transcription factor and are predicted to increase TERT responsive transcription. Interestingly, mutations within the TERT promoter were also present in 25% of pre- neoplastic cirrhotic macro­nodules and 44% of adenomas with malignant transforma- tion. A potential role for TERT deregulation in hepatocarcinogenesis has been previ- ously postulated, but the identifi­cation of mutations in the TERT promoter provides mechanistic insights, establishing a link between TERT alteration and functional deregulation. In fact, Nault et al.6 showed a correlation between mutations in TERT promoter and TERT transcript expression in preneoplastic lesions in hepatocarcino- genesis. Furthermore, the high prevalence of these mutations in preneoplastic lesions points to TERT as the first ‘gatekeeper’ gene Table 1 | Mutation portrait of human hepatocellular carcinoma Gene Pathway/gene function involved Estimated frequency‡ (%) Genes frequently mutated in HCC TERT promoter* Telomere stability 60 TP53 Genome integrity 20–30 CTNNB1 WNT signalling 15–25 ARID1A Chromatin remodelling 10–16 TTN Chromosome segregation 4–10 NFE2L2 Oxidative stress 6–10 JAK1 JAK/STAT signalling 0–9 AXIN1 WNT signalling 4–9 ARID2 Chromatin remodelling 5–7 KEAP1 Ubiquitination 3–8 Genes frequently mutated in other solid tumours, but rarely muted in HCC IDH1, IDH2 NAPDH metabolism <5 EGFR Growth factor signalling <5 BRAF RAS/MAPK signalling <5 KRAS, NRAS RAS/MAPK signalling <5 PIK3CA AKT signalling <5 PTEN AKT signalling <5 *TERT mutation frequency based on targeted sequencing.6 ‡ Based on deep-sequencing studies. Liver cancer is the sixteenth global cause of death and the second cause of cancer death after lung cancer.1 The incidence and mortality from this cancer are increas- ing worldwide.1 Hepatocellular carcinoma (HCC)—the most frequent liver cancer affecting around 700,000 patients every year—occurs in patients with underlying chronic liver disease, a feature that has direct implications in the pathogenesis and management of this neoplasm. High-resolution analysis of molecular alterations in human malignancies has become a research priority. Large-scale mutational screening approaches have enabled the identifi­cation of new disease drivers in some solid tumours such as lung, breast or melanoma. Unfortunately, liver cancer has not reached the point of molecular-based treatment stratifi­cation. Nonetheless, recent studies have provided a broad picture of the mutational profile in HCC and identified an average of 30–40 mutations per tumour, few of which are expected to be driver mutations.2–4 Three independent deep-­sequencing studies confirmed TP53 and CTNNB1 (which encodes for β‑catenin) as frequently mutated in HCC. Mutations in these genes are frequently mutually exclusive.2,3 In addition, these studies discovered novel mutations associated with HCC in differ- ent members of the chromatin remodel­ling pathway (ARID1A and ARID2), in genes involved in ubiquitination (KEAP1), in RAS/MAPK signalling (RPS6KA3) and in oxidative stress (NFE2L2). These results allowed Guichard and colleagues3 to group the most relevant molecular alterations in HCC in five major signalling cascades: Wnt signalling, TP53 signalling, Ras signalling, oxidative stress, and chromatin remodel- ling. Recent studies using whole-genome sequencing have also identified mutations © 2014 Macmillan Publishers Limited. All rights reserved
  • 20. 16  |  JANUARY 2014 www.nature.com/reviews CLINICAL ONCOLOGY in HCC, opening new t­herapeutic routes in the c­hemoprevention arena. In terms of changes in clinical decision- making in HCC management, not much progress was made in 2013. After the approval of sorafenib, six randomized con- trolled trials that could have potentially changed the stand­ard of care for patients with HCC, assessing drugs that included brivanib (a FGFR, VEGFR and PDGFR inhibitor), erlotinib (EGFR inhibitor), linifanib (dual inhibitor of VEGFR and PDGFR) and everolimus (mTOR inhibi- tor) have reported negative findings in the first and second-line settings.7,8 The phase III study testing brivanib versus sorafenib in the first-line treatment of more than 1,000 patients with advanced- stage HCC did not meet the primary end point of improvement in overall survival with a non-­inferiority design.7 Similarly, the phase III study testing brivanib com- pared with placebo in the second-line setting after disease progression following sorafenib treatment failed to demonstrate survival benefits for brivanib.8 These nega- tive results highlight the intrinsic resistance of HCC to therapies, the specific toxicity profile of patients with underlying liver dis- eases, and the complexity of trial design in this heterogeneous cancer. Of note, none of these studies selected patients based on pre- dicted target deregulation, a paradigm that proved to be remarkably effective in other solid tumours. Therefore, a potential ben- eficial effect in a subset of patients could have been missed as a result of treating the overall population. Luckily, a change in this paradigm is starting to permeate drug development in HCC. A phase III trial testing tivantinib in HCC patients whose tumours have a high-MET expression and a phase II proof-of-concept trial evaluating the MEK inhibitor, refametinib, in patients with tumours h­arbouring RAS mutations are ongoing. When considering the global impact of liver cancer, prevention is the optimal approach. This was clearly demonstrated years ago when a direct correlation between nationwide HBV vaccination programmes and decreased liver cancer incidence was reported in Taiwan. Anti­viral HBV and HCV therapies have been able to decrease and sometimes abrogate the transition from chronic hepatitis to cirrhosis, and thus decrease the incidence of HCC. Specific efforts are still needed to prevent liver cancer development in patients at high risk—mainly those patients with cir- rhosis, who represent approximately 1% of the p­opulation—as one third of them will develop HCC in their lifetime. A 186-gene signature is now able to identify the 20% of cirrhotic patients with the highest risk of developing cancer or who will die due to progressive liver dysfunction.9 This ‘field- effect’ gene signature is enriched in genes involved in inflammation, oxidative stress and cell proliferation (such as IL‑6 and EGF), and might enable patient selection for chemoprevention trials.9 A recent study has likewise elegantly shown the molecular interactions between dysplastic nodules and the microenviron- ment that resulted in the development of liver tumours in experimental models.10 In this study, the researchers found a pivotal role of aberrant IL‑6 expression in malignant transformation, mostly as a consequence of the deregulation of a non-coding RNA (LIN28). The research- ers isolated HCC progenitor cells from different mouse models, and showed that autocrine IL‑6 secretion promotes their malignant transformation.10 Interestingly, the study presents functional evidence on how the malignant potential of these pro- genitor cells is highly dependent on their microenvironment, further emphasizing the role of IL‑6 s­ignalling as a potential c­hemoprevention target. We can, therefore, state that liver cancer has reached ‘the end of beginning’ in terms of genome characterization. There is an overall picture of the mutation rate and distri­bution, but whether these events have a driving role in HCC progression or if they define oncogenic addiction loops in human HCC is still unclear. Results from negative phase III trials in all-comers reinforce the concept that molecular information should be incorpor­ated in the drug development process for liver cancer. Biomarker-driven strategies to known targets or deregulated pathways should be encouraged and rep- resent the future for c­linical trial design in this field. Institute of Liver Studies, Division of Transplantation Immunology and Mucosal Biology, King’s College, Denmark Hill, London SE5 6FE, UK (A. Villanueva). HCC Translational Research Laboratory, BCLC Group, IDIBAPS, Liver Unit, Hospital Clínic, University of Barcelona and ICREA, Villarroel 170, Barcelona 08036, Spain (J. M. Llovet). Correspondence to: J. M. Llovet jmllovet@clinic.cat Acknowledgements J. M. Llovet is supported by grants from the U. S. National Institute of Diabetes and Digestive and Kidney Diseases (1R01DK076986‑01), European Commission-FP7 Framework (HEPTROMIC, Proposal No: 259,744), the Asociación Española Contra el Cáncer, the Samuel Waxman Cancer Research Foundation and the Spanish National Health Institute (SAF‑2010‑16055). Competing interests A. Villanueva declares an association with the following company: Bayer Pharmaceuticals. J. M. Llovet declares an association with the following companies: Bayer Pharmaceuticals, Blueprint, BMS, Imclone-Lilly, Nanostring, Novartis. See the article online for full details of the relationships. 1. Lonzano, R. et al. Global and regional mortality from 235 causes of death for 20 age groups in 1990 and 2010: a systematic analysis for the Global Burden of Disease Study 2010. Lancet 380, 2095–2128 (2012). 2. Cleary, S. P. et al. Identification of driver genes in hepatocellular carcinoma by exome sequencing. Hepatology http://dx.doi.org/ 10.1002/hep.26540. 3. Guichard, C. et al. Integrated analysis of somatic mutations and focal copy-number changes identifies key genes and pathways in hepatocellular carcinoma. Nat. Genet. 44, 694–698 (2012). 4. Kan, Z. et al. Whole-genome sequencing identifies recurrent mutations in hepatocellular carcinoma. Genome Res. 23, 1422–1433 (2013). 5. Chiang, D. Y. et al. Focal gains of VEGFA and molecular classification of hepatocellular carcinoma. Cancer Res. 68, 6779–6788 (2008). 6. Nault, J. C. et al. High frequency of telomerase reverse-transcriptase promoter somatic mutations in hepatocellular carcinoma and preneoplastic lesions. Nat. Commun. http:// dx.doi.org/10.1038/ncomms3218 (2013). 7. Johnson, P. J. et al. Brivanib versus sorafenib as first-line therapy in patients with unresectable, advanced hepatocellular carcinoma: results from the randomized phase III BRISK-FL study. J. Clin. Oncol. 31, 3517–3524 (2013). 8. Llovet, J. M. et al. Brivanib in patients with advanced hepatocellular carcinoma who were intolerant to sorafenib or for whom sorafenib failed: results from the randomized phase III BRISK-PS study. J. Clin. Oncol. 31, 3509–3516 (2013). 9. Hoshida, Y. et al. Prognostic gene expression signature for patients with hepatitis C‑related early stage cirrhosis. Gastroenterology 144, 1024–1030 (2013). 10. He, G. et al. Identification of liver cancer progenitors whose malignant progression depends on autocrine IL‑6 signaling. Cell 155, 384–396 (2013). Key advances ■■ The most prevalent mutations in HCC affect the TERT promoter, TP53 and CTNNB1. Few ‘druggable’ mutations have been reported4,6 ■■ IL‑6 is emerging as a reliable target for chemoprevention strategies in HCC9,10 ■■ After the approval of sorafenib, six pivotal phase III trials reported negative findings7,8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 21. KEY ADVANCES IN MEDICINE JANUARY 2014  |  17 CLINICAL ONCOLOGY MELANOMA IN 2013 Melanoma—the run of success continues Dirk Schadendorf and Axel Hauschild In 2013, new insights on the molecular features of cutaneous melanoma provided a paradigm shift in our understanding of the biology of this disease. Exploiting immune checkpoint blockade and the use of BRAF- targeted or MAPK-targeted agents contributed to important progress in the treatment and management of cutaneous melanoma. Schadendorf, D. & Hauschild, A. Nat. Rev. Clin. Oncol. 11, 75–76 (2014); published online 14 January 2014; doi:10.1038/nrclinonc.2013.246 Melanoma is a common malignancy in the West, causing the majority (75%) of deaths related to skin cancer and with an incidence of 15–25 per 100,000. Despite efforts for early detection and prevention, approxi- mately 20% of patients with melanoma die from their disease. Advanced metastatic melanoma (AJCC stage IV) is associated with a poor prognosis, with a median survival of 6–12 months. Until 2010, no random­ized clinical trial had provided evi- dence for improvement in survival for those with advanced-stage metastatic melanoma. How­ever, recent years have witnessed several prospective randomized phase III trials that demonstrate improvements in progression-free survival (PFS) and overall survival for these patients. In 2013, major advances were made in the molecular understanding of melanoma based on key somatic events, such as muta- tions in BRAF, NRAS or CKIT, which are present in 60–70% of cutaneous melano- mas. These findings rapidly translated into pivotal drug development and subsequently into clinical management. The FDA has approved three targeted agents for the treat- ment of patients with metastatic melanoma harbouring BRAF mutations: the BRAF- inhibitors vemurafenib and dabrafenib; and the MEK inhibitor trametinib. Specifically, vemurafenib was approved in 2011 in the USA and in 2012 in Europe, dabrafenib was approved in 2013 in the USA and Europe and trametinib was approved in 2013 in the USA and is expected to gain approval early in 2014 in Europe. Patients treated in trials that assessed these three drugs exhibited a prolonged PFS and an overall survival benefit for the first time in more than three decades of research in this field.1 Despite these encouraging results, it soon became clear that acquired resistance to targeted treatment would limit the success of these drugs. Researchers, therefore, had to focus on the analyses of resistance mechanisms of BRAF inhibition to opti- mize therapy for meta­static melanoma. The acquired resistance to BRAF inhibi- tion was shown to be the result of MAPK reactiva­tion owing to the emergence of secon­dary mutations in NRAS and MEK1 in a subset of patients.2 These data supported the design of new trials combining BRAF and MEK inhibitors to overcome or delay resistance (NCT01584648, NCT01597908, NCT01689519 and NCT01909453). Studies in animal models have shown that vemurafenib-resistant tumours have a continued dependency on MAPK signal- ling, suggesting that vemurafenib-resistant melanomas might become drug-dependent for their continued proliferation. A discon- tinuous dosing strategy in these xenograft models prevented the emergence of resist- ance.3 This observation has opened up a discussion among clinicians on how to choose the most effective dosing schedule for a drug, as both drug-dependent tumour cell proliferation and induction of prema- ture acquired drug resistance will need to be considered. This question needs to be adequately addressed in controlled clinical trial settings. An alternative mechanism of drug resist- ance is based on the fact that treating mela- noma cells with several anticancer drugs, including cisplatin and vemurafenib, led to the survival of a selected tumour cell sub­ population, consisting of slow-cycling, long- term tumour-maintaining melanoma cells expressing lysine-specific d­emethylase 5B (also known as histone demethylase- JARID1B).4 Interestingly, inhibition of mitochondrial respiration by low-dose oligomycin prevented the emergence of the JARID1B-enriched cell subpopulation and sensitized melanoma cells to therapy.4 This finding is an extremely interesting pre- clinical result that will need to be developed further and, if validated, translated into clinical practice. Besides targeted therapy with BRAF or MEK inhibitors, a second distinct approach has emerged in the clinical management of patients with metastatic melanoma— the modulation of the immunological checkpoint. It is possible to interfere with the control of the immune checkpoint independ­ent of the tumour genetics by using agonistic antibodies that block cyto- toxic T-lymphocyte antigen 4 (CTLA-4), programmed cell death protein 1 (PD-1) or its ligand PD‑L1, three critical molecules for the regulation of the immune system. The use of the anti-CTLA-4 antibody ipili- mumab prolonged median overall survival by 3.7 months in patients with stage IV disease. Although response rates are low using ipilimumab and no fast impact on tumour burden can be expected, long-term survival can be induced, with approximately 20% of treated patients being alive >5 years, leading to speculation of a possible cure for subgroups of patients. Importantly, in 2013, antibodies against PD‑1 and PD‑L1 emerged as breakthrough drugs for the treatment of melanoma with high response rates and long durability. In a study of MK3475, a PD-1 antibody, a total of 135 patients with metastatic melanoma were treated.5 Common adverse events were mostly low grade and the confirmed res­ ponse rates across all cohorts was 38%, with the highest response rate of 52% being in the cohort with the most intensive Photodisc/Getty © 2014 Macmillan Publishers Limited. All rights reserved
  • 22. 18  |  JANUARY 2014 www.nature.com/reviews CLINICAL ONCOLOGY dosing schedule (10 mg/kg every 2 weeks). Response rates were not affected by prior ipilimumab therapy failure and this study reported a PFS of >7 months.5 In parallel, a second anti-PD-1 antibody, nivolumab, has been developed and is being tested in a pivotal registration phase III trial as mono­ therapy versus dacarba­zine in patients with wild-type BRAF metastatic mela- noma (NCT01721772). If successful, this trial will establish an attractive option for patients with BRAF wild-type melanoma, who are still being offered largely i­neffective d­acarbazine therapy. The encouraging results obtained using CTLA-4 or PD‑1 immune checkpoint blockade in advanced-stage disease set the rationale for conducting combination treat- ments using nivolumab and ipilimumab.6 A total of 53 patients received combined nivolumab and ipilimumab, whereas 33 patients received both drugs in sequence. The results from the group treated on the concurrent regimen were promising, with an objective response rate of 40% and evidence of clinical activity observed in 65% of patients. At the maximum toler- able dose (nivolumab 1 mg/kg of body weight and ipilimumab 3 mg/kg), 53% of patients had an objective response, with a rapid tumour response and ≥80% reduc- tion in tumour burden. The 1-year survival rate in this patient group was 81%.6 On the basis of these data, a registration phase III study is ongoing to compare treatment with ipilimumab versus nivolumab versus the combination of both drugs in patients with advanced-stage melanoma (NCT01844505). Considering the results of c­ombining BRAF and MEK inhibitors as well as treatment with anti-PD-1 antibodies, anti-CTLA-4 antibodies or both, ongoing clinical trials are likely to lead to new drug approvals. In the era of BRAF-targeted thera­pies, the current challenge is to establish the optimal setting for using each of these agents, including the best use of ipilimumab in the s­ystematic treatment algorithm for melanoma. The inhibition of the BRAF-mutation- induced oncogenic MAPK signalling path­ way led to an increased tumour immune infiltration in some patients, suggesting a potential interaction of BRAF inhibi- tion and host immunity.7 Preclinical data on poten­tial synergies between CTLA‑4, PD‑1 and PD‑L1 inhibition and MAPK- targeted therapy is emerging, and combi- nation of immune checkpoint blockade and MAPK inhibition are being explored in clinical trials. How­ever, one has to be aware of potential unexpected severe adverse events, such as the hepato­toxicity reported when combining vemurafenib and ipilimumab treatment, which resulted in the termination of a clinical phase I/II trial (NCT01400451).8 In recent years, we have learned that alter- ations in regulatory sequences of pivotal genes can be a cancer driving force. In fact, a disease-segregating germ­line mutation in the promoter of the telo­merase reverse transcriptase (TERT) gene was identified in a melanoma-prone family through linkage analysis and high-­throughput sequen­ cing. This mutation creates a new binding motif for ETS trans­cription factors, result- ing in increased t­ranscription of the TERT promoter responsive genes.9 Screening of the TERT promoter sequence in the DNA extracted from metastatic cell lines or metastatic tumour tissues of patients with sporadic melanoma confirmed a recur- rent UV-light-induced somatic mutation in nearly 80% of samples analysed.9 This observation was confirmed independently by systematic sequencing of human mela- noma genomes.10 The prognostic and clinical implications of this new genetic alteration are unclear, but are an impor- tant issue to tackle in the next few years. Telomerase, the enzyme responsible for telo­mere length maintenance, is over­ expressed in a majority of cancers. Most importantly, the lack of expression of telo­ merase in most normal somatic cells makes it an attractive target for cancer therapy. TERT is the reverse transcriptase subunit of the telomerase enzyme. Currently, several compounds, such as nucleoside analogues and the small molecule BIBR1532, aimed at the inhibition of hTERT, are under develop­ ment and hopefully they will contribute to further p­rogress in the delivery of new cancer therapies. Since 2011, treatment of advanced meta- static melanoma has shifted from chemo­ therapy towards targeted therapy and immuno-oncology. Improving durability and advanc­ing clinical benefit of targeted therapies will require a detailed under- standing of mechanisms leading to resist- ance in order to effectively prevent or delay it. Moreover, breaking the immune toler- ance at the tumour site with anti-PD-1 anti­bodies and the potential for a simul- taneous blockade of multiple immune inhibitory checkpoints by combining dif- ferent agonistic antibodies opens the door for long-term tumour control. With the advent and develop­ment of these new treat- ment approaches, the concept of a cure for patients with melanoma finally seems an achievable goal over the next decade. Department of Dermatology, University Duisburg-Essen, University Hospital Essen, Hufelandstrasse 55, 45147 Essen, Germany (D. Schadendorf). Departments of Dermatology, University Hospital Schleswig-Holstein (UKSH), Campus Kiel, Schittenhelmstrasse 7, 24105 Kiel, Germany (A. Hauschild). Correspondence to: D. Schadendorf dirk.schadendorf@uk-essen.de Competing interests D. Schadendorf and A. Hauschild declare associations with the following companies: Amgen, Bristol–Myers Squibb, Genentech, GlaxoSmithKline, Merck/MSD, Novartis, Pfizer, Roche. See the article online for full details of the relationships. 1. Eggermont, A. M., Spatz, A. & Robert, C. Cutaneous melanoma. Lancet http:// dx.doi.org/10.1016/S0140-6736(13)60802-8. 2. Trunzer, K. et al. Pharmacodynamic effects and mechanisms of resistance to vemurafenib in patients with metastatic melanoma. J. Clin. Oncol. 31, 1767–1774 (2013). 3. Das Thakur, M. et al. Modelling vemurafenib resistance in melanoma reveals a strategy to forestall drug resistance. Nature 494, 251–255 (2013). 4. Roesch, A. et al. Overcoming intrinsic multidrug resistance in melanoma by blocking the mitochondrial respiratory chain of slow-cycling JARID1B (high) cells. Cancer Cell 23, 811–825 (2013). 5. Hamid, O. et al. Safety and tumor responses with lambrolizumab (anti-PD-1) in melanoma. N. Engl. J. Med. 369, 134–144 (2013). 6. Wolchok, J. D. et al. Nivolumab plus ipilimumab in advanced melanoma. N. Engl. J. Med. 369, 122–133 (2013). 7. Knight, D. A. et al. Host immunity contributes to the anti-melanoma activity of BRAF inhibitors. J. Clin. Invest. 123, 1371–1381 (2013). 8. Ribas, A. et al. Hepatotoxicity with combination of vemurafenib and ipilimumab. N. Engl. J. Med. 368, 1365–1366 (2013). 9. Horn, S. et al. TERT promoter mutations in familial and sporadic melanoma. Science 339, 959–961 (2013). 10. Huang, F. W. et al. Highly recurrent TERT promoter mutations in human melanoma. Science 339, 957–959 (2013). Key advances ■■ Key mutational events can be used for developing targeted therapies, leading to improved overall survival, but also to the emergence of acquired resistance1–4 ■■ Antibodies interfering with the immune checkpoint control have a high clinical response rate and durability5,6 ■■ Potential synergies between immune checkpoint inhibitors and MAPK-targeted therapy are emerging, but unexpected adverse events have occurred and combination strategies are currently recommended in clinical trials only7,8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 23. KEY ADVANCES IN MEDICINE JANUARY 2014  |  19 CLINICAL ONCOLOGY CERVICAL CANCER IN 2013 Screening comes of age and treatment progress continues Chris J. L. M. Meijer and Peter J. F. Snijders In 2013, studies confirmed that HPV infection of target cells predisposes to cervical (pre)cancer. In developed countries, HPV screening revealed superior protection than cytology screening. In India, visual inspection of the cervix after acetic acid application significantly reduced cervical cancer mortality after 12 years. Improved survival for women with advanced disease was observed after adjuvant bevacizumab. Meijer, C. J. L. M. & Snijders, P. J. F. Nat. Rev. Clin. Oncol. 11, 77–78 (2014); published online 21 January 2014; doi:10.1038/nrclinonc.2013.252 It has been known that infection with certain high-risk human papillomavirus (hrHPV) types is the main cause of cervi- cal cancer. Despite this knowledge, it is still not clear what factors determine the malignant fate of an HPV infection, which occurs in only a small fraction (1–3%) of infected women. A discrete population of cuboidal epi­ thelial cells of embryonic origin localized in the squamocolumnar junction (SCJ) of the cervix may represent the cellular pre- cursor of most cervical cancers.1 According to the current paradigm of cervical cancer develop­ment, most of the hrHPV infec- tions that develop into lesions lead to new viral progeny (productive infections) and display no signs of cellular transformation. Such lesions are morphologically mani- fested as cervical intraepithelial neoplasia (CIN1 and part of CIN2), and arise from infection of basal cells of the squamous epithelium lining the transformation zone, or ectocervix. Conversely, in the case of transforming infections—as seen in the remaining part of CIN2, CIN3 and cervi- cal cancers—the normal viral life cycle is aborted. Such infections are character­ized by overexpression of the E6 and E7 onco- genes in the proliferating basal cells. It was not known what was responsible for this rather unnatural E6/E7 expression profile. The discovery by Herfs et al.1,2 of the cuboi- dal SCJ cells as a possible progenitor of cer- vical precancer and cancer is likely to pave the way for an explanation. They found that the cuboidal SCJ cells display a unique gene-expression profile and identified a SCJ-specific biomarker protein panel com- prising KRT7, AGR2, MMP7, and GDA. Immunohistochemically, these SCJ bio­ markers were present in all cervical cancers analysed (squamous cell carcinomas (SCC) and adenocarcinomas), most CIN2 and CIN3 lesions (91.8%), and a subset of CIN1 lesions (33.3%).1,2 Interestingly, 24.4% of the SCJ biomarker‑positive CIN1 lesions compared with 0% SCJ biomarker‑­negative CIN1 lesions were diagnosed as CIN2/ CIN3 after 0.5 to 7 years of follow-up.1 The SCJ-specific markers could not be induced by HPV E6 or E7 in vitro in squamous epi­ thelial cells, and the biomarker panel was not expressed follow­ing excision of the SCJ by cone biopsy or loop electrical exci- sion.2 Thus, it was concluded that the SCJ- specific expression profile in CIN lesions and cervical cancers was not acquired during the transformation process, but rather reflects the cell of origin. It is tempt- ing to speculate that hrHPV infection of SCJ cells leads to deregulated E6 and E7 expression, trigger­ing a transforming infection. The high transformation suscep- tibility of cuboidal SCJ cells in relation to squamous cells is supported by the fact that HPV-related (pre)cancerous lesions are up to 20 times more common in the cervix (with a SCJ profile) than in other genital sites lacking a SCJ profile, such as the vagina and vulva.2 If confirmed, the potential implications of this discovery are manifold. Firstly, the absence of SCJ markers in CIN lesions likely reflects a negligible or low risk of malignant transforma- tion and warrants a wait-and-see management. Secondly, this finding might impact the assessment of the clinical value of novel molecular disease markers as candi­date triage markers for the referral of hrHPV-­positive women for colposcopy. Moreover, SCJ markers might provide interest­ing additive or alternative test-of- cure markers for monitoring women for the development of progressive post-treatment CIN2 or CIN3, as radical removal of SCJ- positive cells is likely to be associated with a very low risk of recurrence. Another important publication in 2013 showed that hrHPV-based cervical screening provides 60–70% greater protec- tion against invasive cervical carci­noma than cytology screening.3 The authors had previously been involved in four earlier randomized controlled trials in which hrHPV-based screening was com- pared to cytology-based screening with CIN3 or worse (CIN3+) as the primary outcome measure. These trials comprised Swedescreen, POBASCAM, ARTISTIC and NTCC. To measure efficacy, the relative incidence rates of CIN3+ between hrHPV and cytology arms were compared.4 The researchers found that despite different screening protocols the relative incidence rate ratios (hrHPV versus cytology) of CIN3+ in the second screening round were similar in all trials (Swedescreen: 0.53 [95% CI 0.29–0.98]; POBASCAM: 0.39 [95% CI 0.27–0.53]; ARTISTIC: 0.52 [95% CI 0.28– 0.97]; NTCC: 0.34 [95%CI 0.15–0.75]), with no evidence of statistical heterogeneity between the results of the different studies.4 This indicates that hrHPV-based screening detects persistent high-grade CIN before cytology, thus increasing the probability of treatment before invasion. Although none of these studies was powered to detect invasive cervical cancer, two of them (NTCC and POBASCAM) showed better protection of a negative hrHPV test against i­nvasive cancer.5,6 NPG © 2014 Macmillan Publishers Limited. All rights reserved
  • 24. 20  |  JANUARY 2014 www.nature.com/reviews CLINICAL ONCOLOGY In the pooled analysis by Ronco et al.,3 176,464 women were followed up for a median of 6.5 years to assess outcome according to screening type (hrHPV versus cyto­logy). The cumulative detection of invasive cervical cancer 2 years after enrol- ment was similar in both arms. Thereafter, the relative incidence rate ratio dropped, and after 8 years the cumulative invasive cancer incidence was 46.7 per 100,000 in the hrHPV arm versus 93.6 per 100,000 in the cytology arm. The corresponding overall rate ratio was 0.61. This effect was not due to earlier detection of cancer in the first (prevalent) screen because the detection rate in the first 2.5 years was not significantly different between both arms. The rate ratio of invasive cervical cancer (hrHPV versus cytology) of 0.45 after 2.5 years provides the true gain in reducing the incidence of inva- sive cervical cancer. After a negative screen test at entry, the rate ratio of invasive cervi- cal cancer was 0.30, indicating high efficacy of hrHPV screening. The relative incidence rate ratio was lower for adeno­carcinomas than for SCC, in keeping with the obser- vation that cytology is more efficient in detecting SCC than adeno­carcinomas of the cervix. This is the first publication in the Western world to show a higher efficacy of hrHPV screening compared with cytology for detecting cervical cancer.3 The question of what age should HPV screening start has now been addressed. It is known that in young women cytology has low efficacy for high-grade lesions. In the NTCC study,4 overdiagnosis of regressive CIN lesions in the hrHPV arm had been suggested, which is explained partly by the more-intense follow-up of HPV positive women in the NTCC study and a relatively short screening interval of 3 years. No over- diagnosis was noted in the POBASCAM trial, which had a second screening round after 5 years.5 Ronco et al.3 showed the gain in efficacy with hrHPV screening at 30–34 years is at least as effective, if not better than in older women. They recom- mend starting hrHPV screening at the age of 30 with at least 5‑year intervals. The Dutch Minister of Health has decided that in 2016 population hrHPV-based screening should replace cytology, and should start at the age of 30, with screening rounds at 30, 35, 40, 50 and 60 years. Because HPV screening in India is diffi­ cult to implement, Shastri et al.7 explored visual inspection with acetic acid (VIA) in a cervical screening trial in India and compared the results with women who only obtained cancer education (control group). The quality of screening by primary health-care workers and expert gynaeco- logists was comparable. Using four rounds of cancer education in the control group and VIA screening every 24 months in the inter­vention group, after 12 years they showed a 31% reduction in mortality com- pared with the control group. Participation in screening (89% in VIA group and 79% in the control group), and compliance to treat- ment for invasive cancer in both groups was high (86% and 73%, respectively). These represent hopeful results with simple tech- niques in a country where cervical cancer i­ncidence is high (27 per 100,000 women). Promising results have also been obtained regarding treatment in a study by Tewari et al.8 of a cluster randomized trial carried out in Mumbai. The authors showed that bevacizumab given as an adjuvant to standard chemo­therapy in women with advanced cervi­cal cancer increased overall survival by nearly 4 months compared with standard chemo­therapy alone. The relevance of this finding has recently been highlighted in this journal.9 In summary, the paper of Ronco et al.3 has further strengthened the case for carry­ing out primary HPV screening instead of Pap smear testing. Future perspectives include the development of HPV self-­sampling, opening the way to molecular self-­screening. For girls who have been vaccinated with prophylactic bivalent or quadrivalent HPV vaccine, the conversion to HPV screening will provide a joint approach to cancer pre- vention in the future. In under­developed countries, VIA screening with well-­ educated primary health-care workers also shows important results in reducing cervi- cal cancer mortality. Although these posi- tive results warrant implementation in the short run, long-term prevention strategies should focus on use of prophy­lactic HPV vaccination at prepubertal age, and HPV testing with a cheap method at an older age (≥30 years). For women with advanced- stage cancer, adjuvant treatment with beva- cizumab shows hopeful results. Combined use of new therapies against specific targets involved in c­ervical c­arcinogenesis should be further explored. Department of Pathology,Vrije Universiteit Medical Centre Amsterdam, de Boelelaan 1117, 1084 HV Amsterdam,The Netherlands (C. J. L. M. Meijer, P. J. F. Snijders). Correspondence to: C. J. L. M. Meijer cjlm.meijer@vumc.nl Acknowledgements This work has been made possible by grants from the European Union: FP7 frame work programme agreement no242061 PREHDICT, and agreement no: 603019 COHEAHR. Competing interests C. J. L. M. Meijer has associations with the following companies: GlaxoSmithKline, Qiagen, Roche, Self‑Screen—a spin-off company at the Vrije Universiteit, Amsterdam. P. J. F. Snijders has associations with the following companies: GlaxoSmithKline, Gen‑probe, Roche, Self‑Screen. See the article online for full details of the relationships. 1. Herfs, M. et al. Cervical squamocolumnar junction-specific markers define distinct, clinically relevant subsets of low-grade squamous intraepithelial lesions. Am. J. Surg. Pathol. 37, 1311–1318 (2013). 2. Herfs, M. et al. A discrete population of squamocolumnar junction cells implicated in the pathogenesis of cervical cancer. Proc. Natl Acad. Sci. USA 109, 10516–10521 (2012). 3. Ronco, G. et al. Efficacy of HPV-based screening for prevention of invasive cervical cancer: follow-up of four European randomised controlled trials. Lancet http:// dx.doi.org/10.1016/S0140-6736(13)62218-7 (2013). 4. Arbyn, M. et al. Evidence regarding human papillomavirus testing in secondary prevention of cervical cancer. Vaccine 30 (Suppl. 5), F88–F99 (2012). 5. Rijkaart, D. C. et al. Human papillomavirus testing for the detection of high-grade cervical intraepithelial neoplasia and cancer: final results of the POBASCAM randomised controlled trial. Lancet Oncol. 13, 78–88 (2012). 6. Ronco, G. et al. Efficacy of human papillomavirus testing for the detection of invasive cervical cancers and cervical intraepithelial neoplasia: a randomised controlled trial. Lancet Oncol. 11, 249–257 (2010). 7. Shastri, S. S. et al. Effect of visual inspection with acetic acid (VIA) screening by primary health workers on cervical cancer mortality: a cluster randomized controlled trial in Mumbai, India [abstract]. J. Clin. Oncol. 31 (Suppl.), a2 (2013). 8. Tewari, K. S. et al. Incorporation of bevacizumab in the treatment of recurrent and metastatic cervical cancer: a phase III randomized trial of the Gynecologic Oncology Group [abstract]. J. Clin. Oncol. 31 (Suppl.), a3 (2013). 9. Kirk, R. From ASCO—Gynaecological cancer: advances in cervical cancer screening and treatment. Nat. Rev. Clin. Oncol. 10, 425 (2013). Key advances ■■ HPV infection of specific embryonal, cuboidal target cells in the squamocolumnar junction provides a likely explanation for the development of cervical precancer and cancer1,2 ■■ HPV-based cervical screening provides better protection against cervical cancer than Pap smear screening3 ■■ In low-income countries with poor infrastructure, screening with VIA by well- trained primary health workers shows good results in reducing cervical cancer mortality and should be further implemented7 © 2014 Macmillan Publishers Limited. All rights reserved
  • 25. KEY ADVANCES IN MEDICINE JANUARY 2014  |  21 CLINICAL ONCOLOGY COLORECTAL CANCER IN 2013 Towards improved drugs, combinations and patient selection Hans-Joachim Schmolland Alexander Stein The year 2013 has brought more options for patients with metastatic colorectal cancer (mCRC) with new ways to combine traditional agents, further refinement of predictive molecular for EGFR inhibitors and a new salvage option. Molecular profiling could identify subgroups to further improve treatment selection. Schmoll, H.-J. & Stein, A. Nat. Rev. Clin. Oncol. 11, 79–80 (2014); published online 21 January 2014; doi:10.1038/nrclinonc.2013.254 The year 2013 has given patients with metastatic colorectal cancer (mCRC) new options to improve their survival by bring- ing more drugs, more-effective treatment combinations and more-­precise patient selection to enhance patient benefit (Figure 1). Currently, three chemotherapy drugs (5-­fluorouracil [FOLF], oxalipla- tin [OX], and irino­tecan [IRI]) and five targeted drugs—c­etuximab and panitu- mumab (EGFR antibodies), bevacizumab and aflibercept (VEGF inhibitors), and regorafenib (a multikinase inhibitor)—are available for the treatment of mCRC. Generally, standard first-line regimens contain two chemotherapy drugs and one targeted drug. On the basis of the high effi- cacy of the chemo-triplet FOLFOXIRI and the low intrinsic toxicity of bevacizumab, the four drug combination was a logical next step to test. The large phase III TRIBE trial comparing FOLFOXIRI/bevacizumab with FOLFIRI/bevacizumab showed a superior response rate (65% versus 53%, P = 0.006); an improvement of progression-­free sur- vival (PFS, 12.1 months versus 9.7 months), and overall survival (OS) of 31 months versus 25.8 months favouring the four-drug regimen.1 Treatment was generally well toler­ated although, as expected, more grade 3–4 diarrhoea (11% versus 19%), stomatitis (4% versus 9%) and neutropenia (20% versus 50%) occurred. The efficacy of FOLFOXIRI in combination with bevaci­ zumab was independent of KRAS muta- tional status and, importantly, patients with mutations in BRAF, despite their poor prog- nosis, seem to have a very good outcome with the four drug regimen, indicating that this could be the new t­reatment s­tandard for these patients. Proper selection of patients for targeted drugs is of great importance, regarding toxi­ city, efficacy and cost. The year 2013 has put us a major step ahead towards an even more selective use of EGFR-antibodies, such as panitumumab or cetuximab. A retro­spective analysis of the PRIME study demon­strated that within the ‘classic’ KRAS wild-type population (patients without mutations in exon 2), patients with mutations in other KRAS exons (exon 3 and 4) or in NRAS (exon 2 and 3) did not benefit from the addition of panitumumab to FOLFOX and, moreover, had a non- significantly worse PFS (7.3 months versus 8.0 months, HR 1.28, 95% CI 0.79–2.07, P = 0.33) and OS (HR 1.39, 95% CI 0.91– 2.13, P = 0.12).2 Accordingly, the addition of panitumumab to chemotherapy increased OS and became significant in patients without mutations in exons 2, 3 and 4 of KRAS and NRAS when compared with the classic KRAS wild-type population. These data led to the change in the registration label for panitumumab limit­ing the use to patients without m­utation in exons 2, 3 and 4 of KRAS and NRAS. The need to investigate all types of mutations in KRAS and NRAS is strongly supported by the preliminary reports of the first two trials that compared VEGF versus EGFR inhibitors both in combina- tion with chemotherapy. The FIRE‑3 study (also known as AIO KRK‑0306) assessed FOLFIRI plus cetuximab or bevaci­zumab, and the PEAK study assessed FOLFOX plus panitumumab or bevacizumab. Although both trials showed no differ- ence in response rates, a significantly worse outcome was reported for patients with no mutations in KRAS exon 2 (classi­ cal wildtype)—but with mutations in exons 3 or 4—or mutations in exons 2, 3 and 4 of NRAS, if treated with the EGFR- inhibitor. However patients without muta- tions in KRAS or NRAS in any exon had superior PFS (PEAK: 13.1 months versus 9.5 months, P = 0.02; FIRE-3: 10.4 months versus 10.2 months, P = 0.54), and OS favouring the EGFR inhibitor (PEAK: trend, HR 0.63, 95% CI 0.39–1.02, FIRE-3 33.1 months versus 25.9 months, P = 0.01).3,4 These data further mandate the assessment of all mutations in KRAS and NRAS to predict the efficacy or nega- tive activity of EGFR antibodies. However, superiority of EGFR inhibitors over bevaci- zumab cannot be concluded yet and results from the CALGB trial are awaited. Regorafenib 1L 2L 3L 4L Ras wild-type and mutant type 5FU + bevacizumab FOLFIRI + panitumumab FOLFIRI + cetuximab FOLF(XEL)OX + bevacizumab FOLF(XEL)IRI + bevacizumab FOLF(XEL)IRI + bevacizumab FOLF(XEL)OX + bevacizumab FOLFIRI + aflibercept FOLFOX + panitumumab FOLF(XEL)IRI + bevacizumab FOLF(XEL)OX + bevacizumab FOLFIRI + cetuximab FOLFIRI + aflibercept FOLFOX + cetuximab Panitumumab Cetuximab +/– irinotecan FOLFOXIRI + bevacizumab New treatment options 2013 KRAS/NRAS exon 2,3,4 wild-type Figure 1 | Proposal for a new algorithm for treatment selection based on new clinical and molecular data in 2013. © 2014 Macmillan Publishers Limited. All rights reserved
  • 26. 22  |  JANUARY 2014 www.nature.com/reviews CLINICAL ONCOLOGY The year 2013 also evaluated the role of continuous VEGF inhibition beyond multiple treatment lines with the VEGFR tyrosine kinase inhibitor (TKI) regora­ fenib. In the phase III AIO/TML trial, patients who progressed within 3 months after first-line chemotherapy with either irino­tecan (60%) or oxaliplatin (40%) plus bevacizumab were randomly assigned to second-line crossover chemotherapy with or without bevacizumab.5 Patients with unfavour­able disease and a PFS rate follow- ing first-line treatment of <3 months, were excluded. The ‘bevaci­zumab beyond pro- gression’ approach prolonged median OS significantly by 1.4 months (P = 0.0062) and PFS by 1.6 months (P <0·0001).5 Notably, adverse events did not increase when con- tinuing beva­cizumab in second-line treat- ment. These data are in accordance with the efficacy of aflibercept—another VEGF i­nhibitor—in patients for whom chemo- therapy and bevacizumab treatment had failed, and indicate that the supportive effect of VEGF inhibition together with chemo- therapy is maintained at least in the first-line and second-line setting. For further lines, no data are available with bevacizumab, but strong evidence supports regorafenib as a single agent. Numerous phase III trials evaluating dif- ferent TKIs (vatalanib, sunitinib and cedira­ nib) in combination with chemotherapy showed similar efficacy and less tolerability compared to chemotherapy with and without bevacizumab.6,7 Regorafenib finally suc- ceeded as the first TKI to be licenced as a single agent in the last-line treatment setting for patients with mCRC. In patients after treatment failure with irinotecan, oxalipla- tin, fluoropyrimidines, bevacizumab, and EGFR antibodies (in the case of wild-type or undetermined KRAS status), regora­fenib achieved a small but statistically significant prolongation of OS (6.4 months versus 5 months, P = 0.0052) and PFS (1.9 months versus 1.7 months, P <0·0001) compared with placebo.8 Grade 3 or 4 toxicity was, as expected, higher (54% versus 14%), and typical of this kind of treatment (mainly hand–foot skin reaction, fatigue, diarrhoea, hypertension and rash). It remains unclear whether this improvement in patients refrac- tory to prior therapy is due to the anti-VEGF effect or also due to the inhibition of further kinases. Currently, the availability of an addi- tional last-line option is highly appreciated by patients and oncologists. At the moment, KRAS and NRAS muta- tions are the only validated markers for prediction of a lack of benefit by EGFR inhi- bition, and no marker is available for other drugs used to treat mCRC. Instead of using single molecular or biochemical markers, six clinically different subtypes have been identified by gene-expression profiling, each showing different degrees of activa- tion of Wnt signalling and ‘stemness’, and chemo­therapy response as well as survival in the adjuvant and metastatic settings.9 Apart from showing the sensitivity or resistance to available treatments, such as cetuximab or FOLFIRI, some s­ubtypes—for example, the transit-amplifying cetuximab-­resistant disease—might be sensitive to inhibition of MET. This strategy seems to be promis- ing and helpful not only for patients, but also for accelerated drug develop­ment and testing. Further research in this field will help to better refine and individ­ualize selection of treatment and thus improve the dismal prognosis of patients with mCRC. Besides the evaluation of new agents—­particularly in molecularly defined subgroups such as BRAF‑mutant or HER2-positive mCRC— trials applying techniques such as ‘liquid biopsies’ (such as analysis of circulating DNA or tumour cells) will enable real-time tumour information, which might be useful for treat- ment alterations in the future. With the avail- ability of the salvage option regorafenib, the survival benefit gained by combinations and enhanced use of already available agents and further tailoring according to more-precise predictive molecular markers for EGFR antibodies, the year 2013 has been a relevant step forward in mCRC. Department for Oncology-Haematology, Martin Luther University Halle–Wittenberg, Ernst Grube Strasse 40, Halle 06120, Germany (H. J. Schmoll). Department of Oncology, Haematology, Stem Cell Transplantation with the Section Pneumology, Hubertus Wald Tumour Centre, University Cancer Centre Hamburg, Martinistrasse 52, Hamburg 20246, Germany (A. Stein). Correspondence to: H. J. Schmoll hans-joachim.schmoll@uk-halle.de Competing interests Both authors declare associations with the following companies: Amgen, Bayer, Merck Serono, Roche, Sanofi. 1. Falcone, A. et al. FOLFOXIRI/bevacizumab (bev) versus FOLFIRI/bev as first-line treatment in unresectable metastatic colorectal cancer (mCRC) patients (pts): results of the phase III TRIBE trial by GONO group [abstract]. J. Clin. Oncol. 31 (Suppl.), a3505 (2013). 2. Douillard, J. Y. et al. Panitumumab-FOLFOX4 treatment and RAS mutations in colorectal cancer. N. Engl. J. Med. 369, 1023–1034 (2013). 3. Schwartzberg, L. et al. Analysis of KRAS/NRAS mutations in PEAK: a randomized phase II study of FOLFOX6 plus panitumumab (pmab) or bevacizumab (bev) as first-line treatment (tx) for wild-type (WT) KRAS (exon 2) metastatic colorectal cancer (mCRC) [abstract]. J. Clin. Oncol. 31 (Suppl.), a3631 (2013). 4. Stintzing, S. et al. Analysis of KRAS/NRAS and BRAF mutations in FIRE‑3: a randomized phase III study of FOLFIRI plus cetuximab or bevacizumab as first-line treatment for wild- type (WT) KRAS (exon 2) metastatic colorectal cancer (mCRC) patients [abstract]. Eur. J. Cancer 47, LBA17(2013). 5. Bennouna, J. et al. Continuation of bevacizumab after first progression in metastatic colorectal cancer (ML18147): a randomised phase III trial. Lancet Oncol. 14, 29–37 (2013). 6. Carrato, A. et al. Fluorouracil, leucovorin, and irinotecan plus either sunitinib or placebo in metastatic colorectal cancer: a randomized, phase III trial. J. Clin. Oncol. 31, 1341–1347 (2013). 7. Schmoll, H. J. et al. Cediranib with mFOLFOX6 versus bevacizumab with mFOLFOX6 as first- line treatment for patients with advanced colorectal cancer: a double-blind, randomized phase III study (HORIZON III). J .Clin. Oncol. 30, 3588–3595 (2012). 8. Grothey, A. et al. Regorafenib monotherapy for previously treated metastatic colorectal cancer (CORRECT): an international, multicentre, randomised, placebo-controlled, phase III trial. Lancet 381, 303–312 (2013). 9. Sadanandam, A. et al. A colorectal cancer classification system that associates cellular phenotype and responses to therapy. Nat. Med. 19, 619–625 (2013). Key advances ■■ Upfront four-drug regimen FOLFOXIRI in combination with bevacizumab is superior to standard three-drug combinations, a new option for all patients independent of clinical parameters1 ■■ Further refinement of the mutational status of KRAS and NRAS allows identification of patients deriving no benefit, but potential harm from EGFR inhibitors (mutation in exons 2–4 in KRAS or NRAS), and patients with increased benefit (‘all RAS’ wild type)2 ■■ Continued inhibition of VEGF beyond first-line and second-line treatment and also for salvage treatment is an effective treatment option in terms of progression free survival and overall survival5,8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 27. Editors’ picks of the year Clinical opportunities and challenges in targeting tumour dormancy Jonathan A. Hensel, Thomas W. Flaig and Dan Theodorescu Tumour dormancy is when cancer sleeps undetected for periods that can last up to decades. The therapeutic potential of inducing or maintaining this dormant period is clear. This Review describes the mechanisms of dormancy and uses genitourinary cancers as models to demonstrate how dormancy principles could be exploited clinically. doi:10.1038/nrclinonc.2012.207 Liquid biopsy: monitoring cancer-genetics in the blood Emily Crowley, Federica Di Nicolantonio, Fotios Loupakis and Alberto Bardelli As tumour heterogeneity becomes increasinly important, methods to detect genetic variation have come to the fore. One method with potential clinical utility is the detection of variations in circulating-free DNA. This Review outlines the possibilities and challenges regarding predictive and prognostic markers, and detection of therapeutic resistance. doi:10.1038/nrclinonc.2013.110 Palliative care reduces morbidity and mortality in cancer Gabrielle B. Rocque and James F. Cleary Palliative care is a crucial part of the treatment spectrum for cancer patients. This Review outlines the different elements of palliative care, including communication, quality of life, symptom control, patient satisfaction, resource utilization, and shows how it can benefit patients. doi:10.1038/nrclinonc.2012.211 Colorectal cancer screening—optimizing current strategies and new directions Ernst J. Kuipers, Thomas Rösch and Michael Bretthauer Many methods are available for colorectal cancer screening, ranging from noninvasive stool tests to endoscopy. The strength of any single test must be viewed in the context of a range of factors across the screening programme, including test characteristics, uptake, screenee autonomy, cost, endoscopy performance and long-term follow-up. doi:10.1038/nrclinonc.2013.12 The future of epigenetic therapy in solid tumours—lessons from the past Nilofer Azad, Cynthia A. Zahnow, Charles M. Rudin and Stephen B. Baylin Data from preclinical studies and early clinical trials indicate that low-dose epigenetic-modulating agents can reprogramme tumour cells and override cytotoxic effects that are typically observed at high doses. Optimizing drug dosing and scheduling of epigenetic therapies could catapult these agents to a prominent place in cancer management. doi:10.1038/nrclinonc.2013.42 Emerging targeted agents in metastatic breast cancer Dimitrios Zardavas, José Baselga and Martine Piccart Novel targeted agents have had a great impact on treatment at all stages of the breast cancer disease trajectory. Treatment options for patients with metastasis are discussed, with a focus on agents that target the tumour, breast cancer stem cells and the microenvironment. doi:10.1038/nrclinonc.2013.29 Access to cancer medications in low- and middle-income countries Gilberto de Lima Lopes Jr, Jonas A. de Souza and Carlos Barrios Many challenges exist for patients in low and middle-income countries, prompting them to use generic and biosimilar drugs, expanding participation in clinical trials, implementing universal health-care schemes, and using compulsory licensing schemes to increase access to cancer medications for their citizens. doi:10.1038/nrclinonc.2013.55 Biopsies: next-generation biospecimens for tailoring therapy Mark Basik, Adriana Aguilar-Mahecha, Caroline Rousseau, Zuanel Diaz, Sabine Tejpar, Alan Spatz, Celia M. T. Greenwood and Gerald Batist Insights into tumour biology require biospecimens from the primary tumour and those that reflect the patient’s disease in specific contexts. This Review outlines the existing procedures for sample procurement and processing of next-generation biospecimens, and highlights the issues involved in this endeavour. doi:10.1038/nrclinonc.2013.101 Drug rechallenge and treatment beyond progression —implications for drug resistance Elizabeth A. Kuczynski, Daniel J. Sargent, Axel Grothey and Robert S. Kerbel Patients often respond to reintroduction of the same therapy (drug rechallenge) following relapse or disease progression. The authors discuss the available data on drug rechallenge, the potential mechanisms explaining tumour re-sensitization with reintroduced or continued therapy, and why drug resistance definitions need to be re-evaluated. doi:10.1038/nrclinonc.2013.158 Circulating tumour cells and cell-free DNA as tools for managing breast cancer Leticia De Mattos-Arruda, Javier Cortes, Libero Santarpia, Ana Vivancos, Josep Tabernero, Jorge S. Reis-Filho and Joan Seoane Circulating blood biomarkers are promising non-invasive real-time surrogates for tumour tissue-based biomarkers, and in breast cancer they have been used as tools for diagnosis, prognostication, prediction, therapeutic response, and resistance. This Review outlines the techniques, challenges and possibilities of this promising area. doi:10.1038/nrclinonc.2013.80 February 2014 volume 11 no. 2 www.nature.com/reviews YEAR IN REVIEW 2013 Leading oncologists highlight the key research advances from the past year Rapid learning for precision oncology Overcoming key challenges CLINICAL ONCOLOGY nrclinonc_OFC_FEB14.indd 1 14/01/2014 16:34 * * * * * * * * * * A selection of articles published during 2013 in Nature Reviews Clinical Oncology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Clinical Oncology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 28. KEY ADVANCES IN MEDICINE JANUARY 2014  |  23 ENDOCRINOLOGY PUBERTY IN 2013 Unravelling the mystery of puberty Sergio R. Ojeda and Alejandro Lomniczi In 2013, considerable progress was made towards deciphering the molecular foundations of puberty. Loss of transcriptional repression was identified as a core mechanism underlying the onset of puberty, and this loss was found to be precipitated by epigenetic cues. It was also discovered that nutritional deprivation delays puberty by repressing reproductive neuroendocrine function. Ojeda, S. R. & Lomniczi, A. Nat. Rev. Endocrinol. 10, 67–69 (2014); published online 26 November 2013; doi:10.1038/nrendo.2013.233 During the past decade, substantial efforts have been made to identify the genes that, operating within the neuroendocrine brain, might ultimately be responsible for the initi­ ation of puberty. The picture that is emerg­ ing is one of complexity but also of exquisite coordination and functional integration. The dis­covery that mutations in KISS1R (which encodes the receptor for kisspeptins) cause hypo­thalamic hypo­gonadism1,2 drove the iden­tification of various components of the sys­tem that regulates puberty and the com­ plexitiesoftheinteractionswithinthissys­tem. These investigative efforts led to the realiza­ tion that the initiation of puberty requires the involvement of many other genes, such as TAC3, TAC3R and LEPR.3,4 These genes also seem to be organized into functionally connected networks that affect various steps along the neuroendocrine cascade that sets the pubertal process in motion.3 A prevailing view of the initiation of puberty is that during the prepubertal period, neurons secreting g­onadotropin- releasing hormone (GnRH) are subjected to persistent trans-synaptic inhibition. When this inhibition is lifted, GnRH secretion increases, which leads to puberty.5 As loss of inhibitory inputs alone would not suffice to set puberty in motion, it was recognized that a gain in excitatory inputs to GnRH neurons is required.5 Kisspeptin neurons have emerged as a major component of this excitatory input, as kisspeptin signalling is necessary for puberty to occur.1,2 Kisspeptin neurons of the arcuate nucleus (ARC) in the hypothalamus seem to be essential for pulsatile GnRH release in both sexes. How­ ever, whilst kisspeptin neurons are almost absent in the anteroventral peri­ventricular nucleus (AVPV) of the hypothalamus of male indivi­duals, they are required for the preovulatory surge of gonado­tropins in female individuals.6 Does this finding mean that a change in inhibitory inputs is irrelevant to puberty? On the contrary, in 2013 we learned that a basic mechanism of inhibition–activation does indeed exist, but it operates at a tran­ scriptional level. This mechanism not only affects the output of a primary excitatory system (kisspeptin neurons) that controls pul­satile GnRH secretion, but importantly, is sub­jected to epi­genetic regulation.7 In 2013, Lomniczi et al.7 showed that Kiss1 expres­ sion in the ARC of female rats is subjected to a repressive state exerted by the polycomb group (a protein complex). At the initiation of puberty, promoter DNA methylation of two key members of this complex (Eed and Cbx7) increases, expression of both genes decreases, and association of their protein products with the Kiss1 promoter declines. This change to the pro­moter coincides with an increase in the expres­sion of Kiss1 and changes in the chroma­tin status of the Kiss1 promoter. Marked increases occur in the levels of histone H3 Lys4 trimethyla­ tion and histone H3 acetylated at Lys9 and Lys14, two histone marks associated with gene activation. A gradual loss was found in levels of histone H3 Lys27 trimethylation, a repressive histone modification catalysed by the polycomb group complex. Inhibition of DNA methylation prevented the peri­ pubertaldecreasein Eedand Cbx7 expression and the removal of EED and CBX7 from the Kiss1 promoter, which resulted in puberty not occurring. A direct causal relationship between polycomb-mediated inhibition and the timing of puberty was established by the finding that overexpression of EED in pre­ pubertal female rats blunted pulsatile GnRH release, delayed the initiation of puberty and compromis­ed fertility.7 These findings raised the important ques­ tion of why mutations in genes that encode transcriptional repressors had never been reportedinhumanswithdis­ordersofpuberty. A definitive answer to this ques­tion was pro­ vided just 3 months after the publi­cation of the Lomniczi paper by the demon­stration that mutations in MKRN3 are res­ponsible for several cases of familial central preco­cious puberty.8 MKRN3 is a maternally imprinted gene, that is, the copy of the gene derived from the mother is not expressed. Abreu et al.8 studied a cohort of 40 patients with central precocious puberty from 15 fami­ lies and observed that the MKRN3 gene had Key advances ■■ Transcription of Kiss1, a gene required for the initiation of puberty, is repressed in the ARC of the rat hypothalamus before puberty by the polycomb group transcriptional silencing complex7 ■■ This repression is lifted at the initiation of female puberty by epigenetic cues, including changes in DNA methylation and gaining histone marks associated with gene activation7 ■■ Inactivating mutations of MKRN3, a gene predicted to have transcriptional repressive activity, results in precocious puberty in both girls and boys8 ■■ Loss of MKRN3 function underlies many cases of familial pubertal precocity8 ■■ Circulating levels of FGF21, a growth factor of liver origin, increase in response to fasting and delay female puberty by suppressing the preovulatory surge of gonadotropins10 ■■ FGF21 exerts this effect by inhibiting expression of the gene that encodes vasopressin in SCN neurons, resulting in loss of this stimulatory input to kisspeptin neurons of the AVPV10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 29. 24  |  JANUARY 2014 www.nature.com/reviews ENDOCRINOLOGY deleteriousmutationsinfiveofthesefamilies. MKRN3 is located on chromosome 15q11.2,9 the region in which the mutations that cause Prader–Willi syndrome occur; however, the findings of Abreu and colleagues suggest that mutations in MKRN3 are responsible for the precocious puberty seen in these patients but not for other features of Prader–Willi sy­ndrome, such as developmental delay. MKRN3 does not contain introns and encodesaproteinwithaRINGfingerdomain and several zinc finger motifs,9 which indi­ cates the protein has activity similar to that of ubiquitin ligases. In this sense, MKRN3 is remarkably similar to IRF2BPL, another protein with a RING finger domain and that has been implicated in controlling the initia­ tion of puberty and reproductive function.3 The decline in hypothalamic expression of Mkrn3 that was observed in mice during pre­ pubertaldevelopmentandthelossofMKRN3 function in patients with precocious puberty strongly suggest that MKRN3 represses the initiation of puberty.8 As such, these find­ ings provide the first example of a gene that controls puberty by potentially repressing downstream targets instead of activating the GnRH neuronal network. The results of Abreu and co-workers are in keeping with the emerging notion that members of the zinc finger family of genes might be tran­ scriptional repressors of the pubertal pro­ cess in higher primates, including humans.3 These findings also complement the notion put forward by Lomniczi et al.7 that tran­ scriptional repression is a core component of theneuro­endocrinecircuitrythatregulatesthe timing of puberty. The two aforementioned studies iden­ tify regulatory components that underlie the ability of the hypothalamus to govern pulsatile GnRH release, but do not address the process by which puberty is completed in female individuals via the first pre­ ovulatory surge in levels of gonadotropins. Clearly, this surge is elicited by an increase in GnRH release that is in turn induced by estrogen via a mechanism involving kiss­ peptin neurons of the AVPV. However, little was known about the pathways by which peripheral signals associated with metabolic activity regulated this process. Owen et al.10 ended this state of affairs by showing that fibroblast growth factor 21 (FGF21), a cir­ culating form of FGF that originates in the liver, is a peripheral signal that is secreted in response to short-term (<24 h) nutritional deprivation and inhibits the preovulatory surge in levels of gonadotropins by acting on vasopressin neurons of the supra­chiasmatic nucleus (SCN). These investigators showed that FGF21 acts on the SCN via β‑klotho FGF co-receptors to suppress vasopressin gene expression. This suppression results in loss of vasopressin-dependent stimulation of kisspeptin neurons in the AVPV. Taken together, these studies7,8,10 offer a tantalizing new view of the central and peri­ pheral mechanisms responsible for initiat­ing puberty (Figure 1). Instead of occurring at the level of trans-synaptic communica­tion, the central control of puberty is pro­vided by upstream mechanisms that involve gene silencing. Whilst this process has been mech­ anistically identified in the case of poly­comb group genes, much remains to be done in the case of MKRN3. However, the structural fea­ tures of this gene and its pattern of expression in the developing hypo­thalamus suggest that MKRN3—and possibly other gene products from the zinc finger gene family—might function much like polycomb group proteins as silencers of downstream genes that activate puberty,suchasKISS1.Thedemonstrationby OwenandcolleaguesthatFGF21,asaperiph­ eral signal, delays the completion of puberty by repressing vasopressin expression in SCN neurons agrees with the nascent concept that envisions transcriptional repression as a key mechanism controlling the initiation of mammalian puberty. Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Science University, 505 NW 185th Avenue, Beaverton, OR 97006, USA (S. R. Ojeda, A. Lomniczi). Correspondence to: S. R. Ojeda ojedas@ohsu.edu Acknowledgements The authors’ work is supported by a grant from the USA National Science Foundation (IOS1121691). Competing interests The authors declare no competing interests. 1. Seminara, S. B. et al. The GPR54 gene as a regulator of puberty. N. Engl. J. Med. 349, 1614–1627 (2003). 2. de Roux, N. et al. Hypogonadotropic hypogonadism due to loss of function of the KiSS1-derived peptide receptor GPR54. Proc. Natl Acad. Sci. USA 100, 10972–10976 (2003). 3. Lomniczi, A., Wright, H., Castellano, J. M., Sonmez, K. & Ojeda, S. R. A system biology approach to identify regulatory pathways underlying the neuroendocrine control of female puberty in rats and nonhuman primates. Horm. Behav. 64, 175–186 (2013). 4. Sykiotis, G. P., Pitteloud, N., Seminara, S. B., Kaiser, U. B. & Crowley, W. F. Jr. Deciphering genetic disease in the genomic era: the model of GnRH deficiency. Sci.Transl. Med. 2, 32rv2 (2010). 5. Ojeda, S. R. & Terasawa, E. in Hormones, Brain and Behavior Vol. 4 (eds Pfaff, D. et al.) 589–659 (Elsevier, New York, 2002). 6. Pinilla, L., Aguilar, E., Dieguez, C., Millar, R. P. & Tena-Sempere, M. Kisspeptins and reproduction: physiological roles and regulatory mechanisms. Physiol. Rev. 92, 1235–1316 (2012). 7. Lomniczi, A. et al. Epigenetic control of female puberty. Nat. Neurosci. 16, 281–289 (2013). Ovaries MKRN3 (other ZNFs?) Polycomb group POLII AVPV Kisspeptin neuron GnRH neuron AVP neuron SCN ARC Puberty-activating genes (e.g. Kiss1) Hypothalamus Median eminence Pituitary gland Estradiol Luteinizing hormone Follicle-stimulating hormone Estradiol Liver Fasting FGF-21 Figure 1 | The repressive control of puberty. In the ARC, two gene-silencing systems are involved; the polycomb group complex and MKRN3. At the AVPV level, the completion of puberty is delayed by FGF21. Abbreviations: ARC, arcuate nucleus; AVP, vasopressin; AVPV, anteroventral periventricular nucleus; FGF21, fibroblast growth factor 21; MKRN3, makorin ring finger protein 3; SCN, suprachiasmatic nucleus; ZNFs, member of the zinc finger family of proteins. © 2014 Macmillan Publishers Limited. All rights reserved
  • 30. KEY ADVANCES IN MEDICINE JANUARY 2014  |  25 ENDOCRINOLOGY 8. Abreu, A. P. et al. Central precocious puberty caused by mutations in the imprinted gene MKRN3. N. Engl. J. Med. 368, 2467–2475 (2013). 9. Jong, M. T. et al. A novel imprinted gene, encoding a RING zinc-finger protein, and overlapping antisense transcript in the Prader– Willi syndrome critical region. Hum. Mol. Genet. 8, 783–793 (1999). 10. Owen, B. M. et al. FGF21 contributes to neuroendocrine control of female reproduction. Nat. Med. 19, 1153–1156 (2013). THYROID CANCER IN 2013 Advances in our understanding of differentiated thyroid cancer Christoph Reiners Studies published in 2013 have addressed the question of whether the rising incidence of differentiated thyroid cancer is actually the result of overdiagnosis. Advances have also been made in the treatment of differentiated thyroid cancer, including improvements in radioiodine therapy. Reiners, C. Nat. Rev. Endocrinol. 10, 69–70 (2014); published online 3 December 2013; doi:10.1038/nrendo.2013.247 Key advances ■■ The rising global incidence of differentiated thyroid cancer (DTC) is strongly related to improved socioeconomic status and increased access to health-care resources2 ■■ However, ‘overdiagnosis’ can explain only about half of the DTC ‘epidemic’; other causal factors have to be investigated systematically2 ■■ Contrary to early clinical stages of DTC that are mostly detected by screening patients with clinically relevant symptoms, patients with advanced DTC need more ‘aggressive’ treatment2 ■■ Molecular profiles of the tumours could help to identify patients with advanced DTC who might benefit from new treatment approaches7 ■■ MAPK kinase inhibitors are effective for DTC caused by RAS mutations, as well as in DTC as a result of BRAF mutations, as they improve the effectiveness of 131 I therapy8 ■■ Children with DTC generally have an excellent prognosis; however, adverse effects of radioiodine treatment must be taken into consideration9,10 The incidence of differentiated thyroid cancer (DTC) is increasing worldwide; how­ ever, mortality rates have not changed. The preva­lence of clinically occult small papil­ lary thy­roid cancers could be as high as 35%, accord­ing to findings from autopsies of young people from the general population.1 The question is whether the apparent ‘epi­ demic’ represents an actual increase in inci­ dence or is simply attributable to increased detection as a result of improvements in screening. In 2013, an analysis of the Sur­ veillance, Epidemiology and End Results (SEER) database in the USA shed light on this enigma.2 Similar analyses provide evi­ dence that improved socio­economic status and increased access to health-care resources are associated with higher rates of papillary thyroid cancer.3,4 These findings are not specific to the USA, as similar observations have been reported in Canada5 and other de­veloped countries.6 Udelsman and Zhang used an interesting and new approach to study the role of endo­ crinologists, general surgeons and the use of ultrasonography as possible underlying confounders for the DTC epidemic.2 They compared incidence data from the SEER database from 1999 to 2009 with the density of endocrinologists and general surgeons (determined using data from a registry that included ~75% of US physicians) and with the frequency of neck ultrasonography in a database of ~32 million US citizens. The greatest annual age-adjusted increase in DTC incidence over this period was 20.6% for women and 16.5% for men; the inci­ dence was highest in the northeastern states and lowest in the southern states, for both sexes. The incidence rates correlated with the densities of endocrinologists and general surgeons and with the frequency of cervical ultrasonography. Applying a multivariate regression model, 57% of the variability in state-level incidence of DTC in men and 49% in women could be explained by the densi­ ties of endocrinologists and general sur­ geons and the use of ultrasonography. Thus, Udelsman and Zhang conclude that approxi­ mately half of the DTC epidemic could be explained by ‘overdiagnosis’, with the other half related to different causes, possibly radiation exposure as a result of increased use of neck CT scans, chemical expo­ sure (for example, endocrine disruptors­) and/or obesity. Thus, patients with incidentally diag­ nosed small, that is, stage T1 (according to the TNM classification system), DTC should not be overtreated with aggressive surgery or radioiodine, as the prognosis of these patients is excellent. Identification of patients who really benefit from more aggressive treatment still needs to be achieved. Another study published in 2013 focused on advanced DTC and distant metastases; its aim was to identify the molecular profiles of patients who benefit most from radioiodine therapy by elucidating the mutational profile of DTC with radioiodine-avid distant meta­ stases and studying their outcome.7 Distant metastases were described in 1–4% of papil­ lary and 7–28% of follicular thyroid cancers at the time of diagnosis.7 The study group consisted of 43 patients, 19 of whom had radioiodine uptake on diagnostic whole- body scans (30% with RAS and 5% with BRAF mutations). However, the genotype did not correlate with the structural response to radioiodine therapy (15 of 16 patients with RAS mutations developed progressive disease). The investigators therefore con­ clude that despite an apparent preserved ability to concentrate iodine, radioiodine therapy might be clinically ineffective, not only in DTC with BRAF mutations, but also in tumours with RAS mutations.7 An important ‘first-in-man’ study in 2013 addresses the possibility of treating patients with advanced DTC and BRAF or RAS mutations who are refractory to radioiodine with MAPK kinase inhibitors.8 The study included 20 patients (mean age 61 years), of whom nine had BRAF mutations and five had RAS mutations. For dosimetry, a com­ bined 124 I‑PET and CT scan was performed before and after probatory treatment with selumetinib (75 mg twice daily for 4 weeks) after stimulation with thyrotropin alfa. If the second PET and CT scan indicated that the metastatic lesion(s) had received a dose of >20 Gy, radioiodine therapy was performed at the maximum tolerable dose with continued selumetinib treatment. Selumetinib increased the uptake of 124 I in 12 of 20 patients (four with BRAF, five with RAS mutations and three with RET/PTC or no mutations; Figure 1). In eight patients, the dose to the lesion(s) was higher than the cut-off threshold of 20 Gy, which included © 2014 Macmillan Publishers Limited. All rights reserved
  • 31. 26  |  JANUARY 2014 www.nature.com/reviews ENDOCRINOLOGY all the patients with RAS-positive tumours. All eight patients responded to 131 I, with five partial responses and three cases of stable disease (mean of 89% reduction in levels of thyroglobulin). Therefore, selumetinib considerably increases the effectiveness of radio­iodine therapy, especially in patients with RAS mutations. The advantage of this therapeutic approach over long-term treat­ ment with tyrosine kinase inhibitors alone is that only a short course of drug therapy is necessary to induce clinically relevant thera­ peutic responses in patients who otherwise have no treatment options.8 In contrast to the situation in adults with advanced disease, the prognosis for children with DTC is generally excellent, with mortal­ ity rates between 1% and 3% in spite of high rates of lymph-node involvement (60–90%) and of distant metastases (5–30%).9 After the Chernobyl reactor accident, the inci­dence of childhood DTC increased consider­ably in the most affected areas (Belarus, Ukraine and western parts of Russia). A study from researchers in Belarus and Germany addresses the outcome of treatment in a selected,veryhigh-riskcohortof234children from Belarus, of whom 97% had lymph-node involvement and 43% had distant metas­ tases at the time of diagnosis.9 The mean age of the children at the time of the Cher­ nobyl accident was 1.6 years and at the time of surgery the mean age was 12.4 years. The children received treatment with radio­iodine in Germany, which was started a mean of 8 months after surgery and repeated if neces­ sary at intervals of ~6 months. Of the 229 patients who could be included in the analy­ sis,64.2%attainedcompleteremission(deter­ mined by negative 131 I scan and undetectable levels of the tumour marker thyroglobulin), 30.1% had nearly complete remission (nega­ tive scan but TSH-stimulated thyroglobu­ lin levels of 1–10 µg/l) and 4.8% had partial remission (thyroglobulin >10 µg/l and a positive scan, but with decreasing radio­ iodine uptake over time). Only two patients (0.9%) developed recurrences after partial remissions and two patients died, but not as a result of cancer-related causes. Radiological and early clinical signs of pulmonary fibro­ sis (an adverse effect of radioiodine therapy) were observed in 7.2% of patients with dis­ seminated lung metastases and one patient died as a result of severe pulmonary fibrosis 17.5 years after therapy. These findings indi­ cate that pulmonary fibrosis as an adverse effect associated with radioiodine treat­ ment has to be taken seriously, particularly in young children. In addition, the risk of secondary cancers induced by radioiodine is considered to be higher in children than in adults, as the radiation-related risk of cancer induction is negatively correlated with age.8 A study in adults using the large SEER database yielded results consistent with pre­ vious publications that the risk of secon­dary cancersatallsites(butparticularlyforcancers Figure 1 | A whole-body maximum-intensity projection image (from a 124 I PET–CT scan) of a patient with a BRAF-mutant papillary thyroid cancer before and after treatment with selumetinib. New iodine uptake is shown in nearly all previously negative lung and neck metastases. Permission obtained from the Massachusetts Medical Society © Ho, A. L. et al. N. Engl. J. Med. 368, 623–632 (2013). Baseline After selumetinib of the salivary glands and the kidneys) is increased after radioiodine therapy of DTC.10 However, as children with DTC could not be analysed separately, follow-up studies in young patients with DTC are necessary. To summarize: the incidence of thyroid cancer is increasing; however, treatment of patients with early stages of thyroid cancer should not be aggressive, as the prognosis is very good in patients with thyroid cancer that is detected incidentally. In patients with advanced disease, genetic profiling and new molecular drugs might support treatment with radioiodine. In young patients, the risk of adverse effects from radioiodine (such as lung fibrosis and secondary cancers) has to be taken into account. Department of Nuclear Medicine, University Hospital of Würzburg, Oberdürrbacherstraße 6, D‑97080 Würzburg, Germany. reiners_c@ukw.de Competing interests The author declares no competing interests. 1. Franssila, K. O. & Harach, H. R. Occult papillary carcinoma of the thyroid in children and young adults. A systemic autopsy study in Finland. Cancer 58, 715–719 (1986). 2. Udelsman, R. & Zhang, Y. The epidemic of thyroid cancer in the United States: the role of endocrinologists and ultrasounds. Thyroid http://dx.doi.org/10.1089/thy.2013.0257. 3. Li, N., Du, X. L., Reitzel, L. R., Xu, L. & Sturgis, E. M. Impact of enhanced detection on the increase in thyroid cancer incidence in the United States: review of incidence trends by socioeconomic status within the surveillance, epidemiology, and end results registry, 1980–2008. Thyroid 23, 103–110 (2013). 4. Morris, L. G., Sikora, A. G., Tosteson, T. D. & Davies, L. The increasing incidence of thyroid cancer: the influence of access to care. Thyroid 23, 885–891 (2013). 5. Guay, B., Johnson-Obaseki, S. E., McDonald, J. T., Connell, C. & Corsten, M. Incidence of differentiated thyroid cancer by socioeconomic status and urban residence: Canada 1991–2006. Thyroid http:// dx.doi.org/10.1089/thy.2013.0308. 6. Lee, T. J., Kim, S., Cho, H. J. & Lee, J. H. The incidence of thyroid cancer is affected by the characteristics of a healthcare system. J. Korean Med. Sci. 27, 1491–1498 (2012). 7. Sabra, M. M. et al. Clinical outcomes and molecular profile of differentiated thyroid cancers with radioiodine-avid distant metastases. J. Clin. Endocrinol. Metab. 98, E829–E836 (2013). 8. Ho, A. L. et al. Selumetinib-enhanced radioiodine uptake in advanced thyroid cancer. N. Engl. J. Med. 368, 623–632 (2013). 9. Reiners, C. et al. Twenty-five years after Chernobyl: outcome of radioiodine treatment in children and adolescents with very high-risk radiation-induced differentiated thyroid carcinoma. J. Clin. Endocrinol. Metab. 98, 3039–3048 (2013). 10. Kim, C. et al. The risk of second cancers after diagnosis of primary thyroid cancer is elevated in thyroid microcarcinomas. Thyroid 23, 575–582 (2013). © 2014 Macmillan Publishers Limited. All rights reserved
  • 32. KEY ADVANCES IN MEDICINE JANUARY 2014  |  27 ENDOCRINOLOGY STEROID HORMONES IN 2013 Glucocorticoids—timing, binding and environment Stafford L. Lightman and Charlotte L. George 2013 has revealed interesting mechanisms that explain how glucocorticoid signalling responses can be influenced by childhood trauma, activity of other signalling molecules, glucocorticoid circadian rhythms and the sequence of DNA regulatory regions. In particular, studies this year highlight how different signalling environments can determine the molecular and physiological responses of glucocorticoids themselves, and how glucocorticoids can affect other signalling systems. Lightman, S. L. & George, C. L. Nat. Rev. Endocrinol. 10, 71–72 (2014); published online 24 December 2013; doi:10.1038/nrendo.2013.257 Glucocorticoids bind to the mineralo­cor­ ticoid receptor (MR) and glucocorticoid receptor (GR) to either induce rapid ‘non­ genomic’ effects that affect the interactions of existing proteins or molecules in signal­ ling cascades, or regulate the expression of target genes to alter protein expression. The majority of research into glucocorticoid actions has focused on the regulation of gene induction, whereas relatively little is known about how GR binds directly to DNA to repress transcription. Research has predomi­ nantly focused on how GR inhibits tran­ scription by ‘tethering’ to other DNA-bound proteins, or how two GR molecules interact­ ing as a dimer bind directly to specific DNA sequences (called gluco­corticoid response elements [GREs]) to induce transcription. In 2013, Hudson et al.1 investigated how GR interacts with DNA at genes whose expression is inhibited by glucocorticoids. The researchers assessed the crystal struc­ ture of GR bound to a DNA sequence termed a negative GRE (nGRE), which has been found near many genes.2 The particu­ lar nGRE they studied inhibits transcrip­ tion of the thymic stromal lymphopoietin gene. Hudson et al. show that the DNA sequence of this nGRE forces GR to bind to this sequence as two separate molecules, each interacting with opposite sides of the DNA helix, thereby preventing GR dimeri­ zation interactions.1 Indeed, the nGRE DNA structure promotes GR to act as a monomer, which inhibits transcription. These results highlight a new model of GR‑mediated gene repression that might be relevant for other nGRE sequences.2 Miranda et al.3 have also emphasized the importance of GR and DNA binding inter­ actions (Figure 1). Chromatin des­cribes DNA that is wrapped around histones, creating a structure that when open or ‘acces­ sible’ is associated with gene transcription, but when compacted or ‘closed’ is associ­ ated with gene repression. Overwhelmingly, transcription factor binding occurs in acces­ sible chromatin, but GR and related recep­ tors, such as the estrogen receptor (ER) can ‘open’ closed regions to enable binding of t­ranscriptional machinery to induce gene expression. GR and ER are known to modulate each other’s transcriptional responses. To inves­ tigate this crosstalk, Miranda et al. assessed the in vitro genome-wide DNA binding pat­ terns of GR and ER in mouse mammary cells.3 Co-treatment of the cells with estrogen and gluco­corticoids, causing co-activation of both ER and GR, led to the rearrangement of numerous DNA binding sites of both receptors, compared to when they are acti­ vated individually. Importantly, upon induc­ tion, GR actively increased the chromatin accessibility of a number of regions, which then enabled the binding of ER to sites that were pre­viously inaccessible (Figure 1). Similarly, ER could aid the binding of GR to new regions.3 Co-activation of glucocor­ ticoids with other signalling systems can, thus, reprogram the genomic response of both systems, which suggests that perturba­ tion to either system can affect the other sys­ tem’s function. As glucocorticoid signalling varies over a daily (circadian) and shorter ultradian timeframes,4 it will be interesting to see if these fluctuations in GR activity induce oscillations in the binding profile of ER and other DNA-interacting molecules. If so, these interacting signalling systems may be important in understanding pathological processes related to the circadian or stress- related changes in glucocorticoid exposure that have been implicated in disease.4 The importance of circadian fluctua­ tions in glucocorticoid levels have also been highlighted in 2013.5 Liston et al. studied transgenic mice with fluorescent neurons in the motor cortex of the brain to enable the effects of circadian glucocorticoid exposure on the structure of the neurons to be moni­ tored in vivo. The particular phase of the circadian rhythm in glucocorticoid secre­ tion was found to be important in memory GR increases accessibility aiding ER binding ER ER ER GR GR GR GR ER GR ER Already accessible GR DNA binding site Closed GR DNA binding site ER ER ER Gene a b Figure 1 | ER and GR bind to specific DNA binding sites to regulate the expression of their target genes (arrows indicate transcription). a | ER binding sites (blue DNA regions) when estrogen is present and GR is inactive. b | Most potential GR binding sites are in accessible regions of chromatin (green regions), but when activated by glucocorticoids, GR can also remodel tightly compacted GR binding sites (red regions) into accessible chromatin that other transcription factors can then bind. Simultaneous activation of ER and GR enables GR to bind DNA and regulate glucocorticoid-responsive genes and also allows ER to access newly ‘opened’ regions. Abbreviations: ER, estrogen receptor; GR, glucocorticoid receptor. © 2014 Macmillan Publishers Limited. All rights reserved
  • 33. 28  |  JANUARY 2014 www.nature.com/reviews ENDOCRINOLOGY formation and retention. Temporarily high levels of glucocorticoids at the time of learning (for example, during the evening circadian peak) were required to increase memory of the motor skills required by the mice. These high levels of glucocorticoids also increased the number of new spines formed by neu­rons, via a rapid GR‑mediated nongenomic me­chanism involving LIM kinase signalling. Low levels of glucocorticoids during cir­ cadian troughs were required in the days after learning, however, to retain and stabi­ lize the memory.5 This stabilization process depended on the ‘pruning’ of older spines by MR‑mediated changes in gene expres­ sion. The daily glucocorticoid oscillations and fluctu­ations, thus, appear to improve memory function. This study suggests that fluctuations in GR and MR signalling are vital for plasticity in memory-encoding brain regions, which raises important thera­ peutic questions about the optimal ligands and timing for glucocorticoid therapy. These findings also provide insight into the adverse cognitive effects observed in Cushing dis­ease and in individuals treated with gluco­corticoids who lose normal gl­ucocorticoid oscillations. Chronically elevated glucocorticoid levels are associated with memory dysfunction and impaired hippocampal neurogenesis, both of which have been implicated in the pathology of depression.6 In 2013, Anacker and colleagues7 revealed a novel mecha­ nism whereby glucocorticoids decrease hippocampal neurogenesis. The research­ ers assessed the proliferation and differen­ tiation of a human hippocampal progenitor cell line into neurons during glucocorticoid exposure. Anacker et al. found that elevated gluco­corticoids decreased hippocampal neuro­genesis by inducing the activity of SGK1, a protein previously implicated in regulating neuronal excitability. This mechanism is notably impaired by a small molecule inhibitor of SGK1. Glucocorticoids both increased the expression of SGK1 and upregulated SGK1-enhanced GR activa­ tion for several hours after glucocorticoid removal. Increased SGK1 expression was also observed in rodent models of chronic stress and peripheral blood cells of drug-free patients with depression. These findings imply that chronic gluco­ corticoid exposure could result in over­ expres­sion of SGK1, which in turn could fur­ther exacerbate glucocorticoid sig­nalling dysfunction. From a therapeutic perspec­ tive, SGK1 inhibition may reduce unwanted adverse effects resulting from increased GR signalling. Further investigation of the behavioural response to g­lucocorticoid- mediated dys­regulation of SGK1 and decreased neurogenesis in rodents and its poten­tial translation to human depression will be exciting. Given the recently implied role of an increased salt concentration in induc­ing pathological SGK1 signalling in mice,8 studies investigating whether high levels of dietary salt also dysregulate GR sig­ nalling via alterations in SGK1 activity are also eagerly awaited. Finally, in 2013, Klengel et al.9 revealed the molecular mechanisms that explain how environmental exposure to childhood trauma increases the risk of stress-related psychological disorders, including post- traumatic stress disorder (PTSD). These researchers investigated a polymorphism (rs1360780) that is associated with an increased risk of PTSD in individuals who have experienced childhood abuse. The rs1360780 polymorphism is close to a GRE binding site in the FKBP5 gene. This ‘risk’ genotype showed enhanced GR‑mediated FKBP5 transcription by increasing the contact of the GRE with the transcriptional start site. DNA from peripheral blood cells of participants who experienced childhood abuse had decreased DNA methylation at another FKBP5 GRE. Not­ably, this demethy­lation was replicated in vitro by glucocorticoid exposure and also resulted in amplified GR‑mediated FKBP5 transcrip­ tion. FKBP5 can also negatively regulate the activity of GR to reduce its sensitivity to gluco­corticoids. Indeed, individuals with a risk genotype and childhood trauma had altered glucocorticoid-regulated transcrip­ tion in immune cells and altered hippo­ campal m­orphology, which could alter GR signalling.9 2013 has highlighted molecular mecha­ nisms by which factors ranging from the composition of DNA sequences to life experi­ences can alter glucocorticoid sig­ nalling. These findings highlight signalling pathways that may be disrupted in disease and point to novel therapeutic strategies to improve glucocorticoid therapies. This new knowledge has implications for a wide sp­ectrum of diseases. Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, Dorothy Hodgkin Building, University of Bristol,Whitson Street, Bristol BS1 3NY, UK (S. L. Lightman, C. L. George). Correspondence to: S. L. Lightman stafford.lightman@bristol.ac.uk Competing interests The authors declare no competing interests. 1. Hudson, W. H., Youn, C. & Ortlund, E. A. The structural basis of direct glucocorticoid- mediated transrepression. Nat. Struct. Mol. Biol. 20, 53–58 (2013). 2. Surjit, M. et al. Widespread negative response elements mediate direct repression by agonist- liganded glucocorticoid receptor. Cell 145, 224–241 (2011). 3. Miranda, T. B. et al. Reprogramming the chromatin landscape: interplay of the estrogen and glucocorticoid receptors at the genomic level. Cancer Res. 73, 5130–5139 (2013). 4. Lightman, S. L. & Conway-Campbell, B. L. The crucial role of pulsatile activity of the HPA axis for continuous dynamic equilibration. Nat. Rev. Neurosci. 11, 710–718 (2010). 5. Liston, C. et al. Circadian glucocorticoid oscillations promote learning-dependent synapse formation and maintenance. Nat. Neurosci. 16, 698–705 (2013). 6. Sahay, A. & Hen, R. Adult hippocampal neurogenesis in depression. Nat. Neurosci. 10, 1110–1115 (2007). 7. Anacker, C. et al. Role for the kinase SGK1 in stress, depression, and glucocorticoid effects on hippocampal neurogenesis. Proc. Natl Acad. Sci. USA 110, 8708–8713 (2013). 8. Wu, C. et al. Induction of pathogenic TH17 cells by inducible salt-sensing kinase SGK1. Nature 496, 513–517 (2013). 9. Klengel, T. et al. Allele-specific FKBP5 DNA demethylation mediates gene–childhood trauma interactions. Nat. Neurosci. 16, 33–41 (2013). Key advances ■■ The DNA structure of negative glucocorticoid response elements can actively prevent glucocorticoid receptor (GR) dimerization and, thus, repress transcription1 ■■ Activated GR is capable of making the chromatin structure of certain binding regions more accessible, which enables these regions to be bound by other transcription factors and, thereby, alter the transcriptional response of these other proteins3 ■■ In mice, daily circadian fluctuations of glucocorticoids are vital for the morphological neuronal changes associated with memory stabilization and learning a motor skill task5 ■■ In human cells, glucocorticoids impair hippocampal neurogenesis by mechanisms mediated by SGK1, suggesting that targeting this pathway could be exploited for therapeutic benefit7 ■■ Molecular mechanisms have been identified that explain how environmental factors, such as early-life experiences, can interact with a specific genetic polymorphism to dysregulate gene expression and increase an individual’s risk of developing post-traumatic stress disorder9 © 2014 Macmillan Publishers Limited. All rights reserved
  • 34. KEY ADVANCES IN MEDICINE JANUARY 2014  |  29 ENDOCRINOLOGY TYPE 2 DIABETES MELLITUS IN 2013 A central role of the gut in glucose homeostasis Geltrude Mingrone and Lidia Castagneto-Gissey Metabolic surgery has been proven to be effective in inducing remission of type 2 diabetes mellitus prior to any significant weight reduction. Studies in 2013 have investigated the mechanisms of action of these procedures and have highlighted a central role of the small intestine in the effects on glucose homeostasis. Mingrone, G. & Castagneto-Gissey, L. Nat. Rev. Endocrinol. 10, 73–74 (2014); published online 10 December 2013; doi:10.1038/nrendo.2013.241 A peculiar characteristic of bariatric surgery for the treatment of obesity is that glucose disposal improves before any significant weight loss has occurred. Indeed, random­ ized controlled studies have confirmed that bariatric surgery is effective in inducing remission of type 2 diabetes mellitus.1,2 To highlight the metabolic implications, espe­ cially on glucose homeostasis, of some of these operations, they are increasingly being referred to as ‘metabolic surgery’. Discerning the mechanisms underlying the metabolic effects of these procedures is crucial, so that a drug might be developed that repro­ duces the actions on insulin sensitivity, ob­viating the need for invasive surgery. Clinical studies have highlighted changes in the levels of circulating gastrointestinal hormones, such as glucagon-like peptide 1 (GLP‑1) and ghrelin, as possible mecha­ nisms of action. GLP‑1, which is secreted by the intestinal L cells in response to nutri­ ent stimulation, inhibits hepatic glucose production, probably through the inhibi­ tion of glucagon secretion. In addition, this hormone increases insulin secretion in a dose-dependent manner. Circulating levels of GLP‑1 increase markedly after certain types of metabolic surgery, such as Roux- en‑Y gastric bypass (RYGB). Hence, it was proposed that GLP‑1 hypersecretion mediate the effects on glucose homeostasis exerted by this procedure. However, studies published in 2013 have disproven this hypothesis, at least in rodents. What these studies do show is a direct effect of the gastrectomy or the exclusion of some tracts of the small intestine on glycaemic control. In 2013, Wilson-Pérez et al.3 performed vertical sleeve gastrectomy in GLP‑1 recep­ tor wild-type and knockout mice. After the surgery, the GLP‑1 response to a mixed meal administered by gavage was similar in the two groups of animals, that is, GLP‑1 secre­ tion was not impaired in mice with dis­rupted GLP‑1 receptor signalling. Subsequently, wild-type and knockout mice were placed on a high-fat, butter-based diet for 5 weeks, after which researchers measured glucose disposal following a mixed meal. Both mouse strains showed comparable blood glucose levels that weremuchlowerthanthoseofsham-operated mice.3 These results suggest that the effects of meta­bolic surgery on glucose disposal are not mediated by GLP‑1, as in fact vertical sleeve gastrectomy effectively improved gly­ caemic control also in the absence of GLP‑1 receptors. Similarly, Chambers et al.4 showed that vertical sleeve gastrectomy is effective in improving glucose tolerance in wild-type and in ghrelin knockout mice exposed to a high-fat diet for 10 weeks before surgery. In other words, the dramatic reduction of circu­ lating levels of ghrelin in knockout animals didnottranslateintothebenefitsofmetabolic surgery on glucose disposal. The gastric bypass comprises the crea­ tion of a gastric pouch anastomosed to the jejunum immediately after the Treitz ligament, which is also known as the sus­ pensory muscle of the duodenum. The continuity of biliopancreatic secretions is reconstructed in rats by anastomizing the biliopancreatic limb to the alimentary limb of the small bowel 15 cm distal to the gastrojejunal anastomosis in a Roux-en‑Y fashion. This intestinal tract represents the Roux limb. In 2013, Saeidi et al.5 studied the metabolic profile after RYGB in rats with diet-induced obesity, in rats with diabetes mellitus induced by streptozotocin injec­ tion and in Goto-Kakizaki rats, a substrain of nonobese Wistar rats that spontaneously develops type 2 diabetes mellitus early in life. The researchers found that the Roux limb showed intense glucose uptake and utiliza­ tion, as measured by 18 F-FDG-PET–CT in all three animal models.5 In addition, expres­ sion of glucose transporter 1 (GLUT‑1; also known as SLC2A1) was increased in the Roux limb, which might have contributed to the observed increased glucose uptake and utilization.5 Mucosa cells within the Roux limb showed hypertrophy and hyper­ plasia with enhanced aerobic glycolysis to meet the increased energy demand arising from the exposure of the distal jejunum to un­digested food.5 In addition, in a separate group of diet-induced obese and nonobese, diabetic rats, a transected loop of the jejunum transposed between the oesophagus and the stomach demonstrated the same morpho­ logic and functional adaptations observed after RYGB.5 These findings support a role for reprogramming and remodelling of the small intestine as the cause underlying Hypothalamus Jejunum Hepatic glucose production Duodenum Ileum ? Peripheral glucose uptake Nutrient sensor ?? Figure 1 | Activation of the gut–brain–liver neuronal axis under glucose and/or lipid stimulation via a nutrient sensor located in the proximal jejunum. By delivering undigested food into the mid-jejunum, the bypass of the duodenum and the proximal jejunum, as performed in the Roux-en‑Y gastric bypass, might determine the improvement of hepatic insulin resistance, with subsequent reduction of hepatic glucose production. The bypass of the entire jejunum, by contrast, might abolish or drastically reduce the secretion of intestinal hormones that induce peripheral insulin resistance, thus normalizing insulin sensitivity, as observed after biliopancreatic diversion. ▶ © 2014 Macmillan Publishers Limited. All rights reserved
  • 35. 30  |  JANUARY 2014 www.nature.com/reviews ENDOCRINOLOGY the improvement of type 2 diabetes mellitus fo­llowing metabolic surgery. In 2013, our group showed that the duode­ num and the jejunum of diabetic db/db mice secrete proteins of 10–100 kDa in size that can induce insulin resistance in normal mice and inhibit insulin signalling in vitro in rat skeletal muscle cells.6 Similar results were obtained using human myoblasts incubated with proteins secreted from jejunal biopsy samples from insulin-resistant, but not from insulin-sensitive, individuals.6 These secreted proteins acted by stimulating the mammalian target of rapamycin complex 2 (mTORC2),6 which is a serine/threonine kinase composed of mTOR, the rapamycin- insensitive companion of mTOR (known as RICTOR), the TORC subunit LST8, and the TORC2 subunit MAPKAP1. mTORC2 catalyses the phosphorylation of AKT, also known as protein kinase B, at the hydrophobic motif site (Ser473). In human myoblastsandinratmyocytes,AKTregulates cellular trafficking of the glucose transporter GLUT‑4.MaximalactivityofAKTisachieved whenthemoleculeisphosphory­latedonboth Thr308 and Ser473 residues,7 which enables the translocation of GLUT‑4 to the plasma membrane in skeletal muscle and adipose tissue. Muscle-specific Rictor knockout mice exhibit moderately decreased insulin-­ stimulated glucose uptake and glucose intol­ erance,8 butnotoverttype 2diabetesmellitus. In fact, in these animals, the phosphoryla­ tion of AKT at Thr308 alone is able to acti­ vate GLUT‑4 translocation and is sufficient to mediate the phosphorylation of down­ stream targets.8 The secreted 10–100 kDa gut proteins enhance AKT phosphoryla­ tion of Ser473 whereas they inhibit that of Thr308 in vitro, thereby reducing trafficking of GLUT-4 to the cell membrane.6 Increased Ser473 AKT phosphorylation is a typical feature of cancer tissues,9 a disease classically associated with insulin resistance. The effect of secreted gut proteins is reversible after washout of the cells,6 which indicates that this process is mediated by membrane receptors. Taken together, these findings suggest that specific secreted jejunal proteins can impair insulin signalling (Figure 1). Previously, Breen et al. suggested the pres­ ence of a jejunal nutrient sensor, which could explain the early improvement of plasma glucose levels after duodenal and proximal jejunal bypass in decompensated diabetes mellitus of nonobese rat models.10 Altogether the reports published in 2013 support this hypothesis. Bypassing the duodenum and a very proximal portion of the jejunum, as is achieved by RYGB, might stimulate a jejunal nutrient sensor, probably via a neuronal pathway, and thereby trigger a reduction in hepatic glucose production. By contrast, exclusion of the duodenum, entire jejunum and the first portion of the ileum from the nutrient transit, for example, by bilio­ pancreatic diversion, might inhibit the secre­ tion of intestinal hormones that can induce insulin resistance. The discoveries in 2013 regarding the mec­hanisms of action of metabolic surgery on insulin resistance and type 2 dia­betes mel­ litus should foster further intense research devoted to identifying the neuronal path­ way(s) involved and to characterizing the still unidentified intestinal hormones that induce insulin resistance. We are in fact hopeful that a new medical approach will be found in the future that therapeutically mimics the action of metabolic surgery on diabetes remission. Key advances ■■ Diabetes remission after metabolic surgery is not mediated by glucagon-like peptide 1, at least in rodents3 ■■ Glycaemic control is achieved after metabolic surgery even in the absence of ghrelin4 ■■ Exposure of the distal jejunum to undigested food results in hypertrophy and hyperplasia of the mucosa and in overexpression of the glucose transporter GLUT‑1, which increases glucose uptake and utilization and contributes to the improvement of glucose metabolism after bariatric surgery5 ■■ Bypass of the duodenum and the whole jejunum may reduce the secretion of proteins able to impair insulin action both in vivo and in vitro6 Department of Internal Medicine, Catholic University of Rome, Largo A. Gemelli 8, 00168 Rome, Italy (G. Mingrone). Department of Surgery, Università La Sapienza, Viale Regina Elena 324, 00195 Rome, Italy (L. Castagneto-Gissey). Correspondence to: G. Mingrone gmingrone@rm.unicatt.it Competing interests The authors declare no competing interests. 1. Mingrone, G. et al. Bariatric surgery versus conventional medical therapy for type 2 diabetes. N. Engl. J. Med. 366, 1577–1585 (2012). 2. Schauer, P. R. et al. Bariatric surgery versus intensive medical therapy in obese patients with diabetes. N. Engl. J. Med. 366, 1567–1576 (2012). 3. Wilson-Pérez, H. E. et al. Vertical sleeve gastrectomy is effective in two genetic mouse models of glucagon-like peptide 1 receptor deficiency. Diabetes 62, 2380–2385 (2013). 4. Chambers, A. P. et al. The effects of vertical sleeve gastrectomy in rodents are ghrelin independent. Gastroenterology 144, 50–52 (2013). 5. Saeidi, N. et al. Reprogramming of intestinal glucose metabolism and glycemic control in rats after gastric bypass. Science 341, 406–410 (2013). 6. Salinari, S. et al. Jejunal proteins secreted by db/db mice or insulin-resistant humans impair the insulin signaling and determine insulin resistance. PLoS ONE 8, e56258 (2013). 7. Whiteman, E. L., Cho, H. & Birnbaum, M. J. Role of Akt/protein kinase B in metabolism. Trends Endocrinol. Metab. 13, 444–451 (2002). 8. Kumar, A. et al. Muscle-specific deletion of rictor impairs insulin-stimulated glucose transport and enhances basal glycogen synthase activity. Mol. Cell Biol. 28, 61–70 (2008). 9. Godsland, I. F. Insulin resistance and hyperinsulinaemia in the development and progression of cancer. Clin. Sci. (Lond.) 118, 315–332 (2009). 10. Breen, D. M. et al. Jejunal nutrient sensing is required for duodenal–jejunal bypass surgery to rapidly lower glucose concentrations in uncontrolled diabetes. Nat. Med. 18, 950–955 (2012). METABOLISM IN 2013 The gut microbiota manages host metabolism Patrice D. Cani In 2013, studies in rodents and humans have reaffirmed the essential role of the gut microbiota in host metabolism. More importantly, several converging results have increased our knowledge regarding the taxa and functions of the gut microbiota that contribute to the management of energy homeostasis, glucose metabolism and metabolic inflammation. Cani, P. D. Nat. Rev. Endocrinol. 10, 74–76 (2014); published online 10 December 2013; doi:10.1038/nrendo.2013.240 Over the past decade, it has become clear that the inhabitants of our gut, the gut micro­biota, must be considered as a novel partner that is involved in the numerous interactions between our own organs.1 A few years ago, an exciting advance in the field © 2014 Macmillan Publishers Limited. All rights reserved
  • 36. KEY ADVANCES IN MEDICINE JANUARY 2014  |  31 ENDOCRINOLOGY was demonstrated: transplanting the gut microbiota from obese animals replicated the pheno­type in gnotobiotic mice (that is, animals reared free of germs or only in the presence of known or specified micro­ organisms), proving a causal link between gut microbes and host metabolism.2 Using different approaches, key studies from 2013 have identified convergent issues regarding the metabolic functions of the gut microbiota and have pinpointed a restricted number of taxa involved in these functions. The most effective strategy developed for the treatment of obesity and type 2 diabetes mellitus (T2DM), is the gastric bypass, a pro­ cedure characterized by rapid and sustained weight loss. Changes in the abundance of speci­fic gut microbes have been reported in individuals who have undergone a gastric bypass.3 However, a causal link between changes in the gut microbiota induced by gas­tric bypass surgery and the host pheno­ type (that is, weight loss, improved gly­ caemic control and insulin sensitivity) was not demonstrated. In2013,thisproblemwaspartlyresolvedby Liou and colleagues,4 who found that trans­ ferring the gut microbiota of mice that under­went a gastric bypass into germ-free mice that did not undergo surgery decreased body weight and fat mass compared with animals receiving the gut microbiota from sham-surgery donors. In addition, gastric bypass surgery resulted in an increase in the relative abundance of Alistipes, Gamma­ proteobacteria, Akkermansia and Archaea.4 A similar shift in the gut microbiota com­ position had previously been identified in humanswithobesitywhounderwentagastric bypass; in particular, Gammaproteobacteria, Akkermansia and Archaea were enriched aftersurgery.3 Whetherotherbacterialgroups affected by the gastric bypass influence metabolism warrants further investigation. Another discovery by Liou et al. was a change in the levels of short-chain fatty acids (SCFAs): acetate levels were decreased and propionate levels were increased, whereas butyrate concentration was unaffected, both in mice that underwent a gastric bypass and in germ-free animals colonized with the gutmicrobiotafrommicethathadunder­gone agastricbypass,comparedwithanimalscolo­ nized with microbes from control donors. These data suggest that specific taxa and/or metabolicfunctionsareshapedbythesurgery and play a part in host metabolism. Translatingtheseanimalstudiestohumans is extremely difficult because of the relative contributions of early-life development of the gut microbiota, genetic background, dietary habits, and eventually interpersonal differences in the gut microbiota structure. In 2013, Ridaura et al. overcame some of these ob­staclesbyusinganoutstandingstrategy.5 By transferring the gut microbiota from female human twins discordant for obesity into adult germ-free mice, they determined that thephenotypeofobesitywastransmissible.In other words, mice receiving the faecal micro­ biota from the obese twin displayed a greater fat mass than mice receiving the lean twin’s gut microbes. Co-housing obese and lean animals prevented increased adiposity. The researchers identified several members of the Bacteroidetes phylum within the micro­ biota of lean mice that successfully ‘invaded’ the microbiota of obese mice;5 however, whether these species were responsible for the lean-like state remains to be proven. Functional analysis revealed that the microbial gene repertoire, the micro­biome, from mice colonized with the lean twins’ microbiota was enriched with genes involved in the digestion of plant-derived poly­ saccharides and the fermentation of SCFAs, such as butyrate and propionate. Accord­ingly, propionate and butyrate levels were increased in the caecal content of mice colonized with the transplanted microbiota from lean Low-grade inflammation Gut barrier Obesity Diabetes Lean Healthy Homeostasis Fat depots Muscle Liver Homeostasis Fat depots Muscle Liver Intestinal epithelium Inner mucus Gut lumen and mucus Gut microbes and metabolic functions H2 S CH4 H2 O2 H2 S CH4 H2 O2 H2 SH2 S O2 HGC Akk SCFAs Akk SCFAsLGC Glucose, lipid and energy Glucose, lipid and energy Figure 1 | Changes in gut microbiota composition and metabolism. The gut microbiota of healthy individuals is characterized by an abundance of specific genes (that is, HGC) or specific bacteria (for example, Akkermansia) or metabolites, such as SCFAs, that interfere with the host gut-barrier function and metabolism. Obesity and type 2 diabetes mellitus are characterized by a lower abundance of specific bacteria, SCFAs and LGC, thereby leading to gut-barrier dysfunction, low-grade inflammation and altered glucose, lipid and energy homeostasis. Abbreviations: Akk, Akkermansia; HGC, high gene count; LGC, low gene count; SCFA, short-chain fatty acids. twins.5 By contrast, the micro­biome from obese twins had 305 enzymes that were dif­ ferentially expressed.5 Collectively, these data highlight the need to examine the relation­ ships between gut microbes and physiologi­ cal parameters, not only at the taxo­nomic level but also at the level of the meta­bolic functions and metabolites re­sulting from these complex interactions. Partially addressing this need, two studies in 2013 of different cohorts of indivi­duals demonstrated that the richness of gut micro­ bial genes, and microbial composition, corre­lates with susceptibility to weight loss upon dietary restriction6 and with meta­ bolic markers (for example, body weight, fat mass, inflammation, glucose and lipid metabolism).7 Using multiple sequenc­ ing technologies, the researchers detected a bimodal distribution of microbial genes.7 They stratified the population as ‘low gene count’ (LGC) and ‘high gene count’ (HGC), according to the number of genes in the gut microbiome, which gives an indica­ tion of the different microbial communities present as well as their different metabolic functions. Individuals with an LGC (23% of the popu­lation) were characterized by more marked weight gain over time, adipo­ sity, insu­lin resistance and inflammation © 2014 Macmillan Publishers Limited. All rights reserved
  • 37. 32  |  JANUARY 2014 www.nature.com/reviews ENDOCRINOLOGY than HGC indivi­duals.7 Moreover, micro­ bial gene rich­ness was modified in part by dietary intervention.6 Very interestingly, dietary restriction was less efficient in LGC than in HGC individuals.6 These findings suggest that the efficacy of dietary interven­ tion can be predicted through stratification by microbi­al gene richness. The abundance of several taxa was signifi­ cantly associated with bacterial gene richness and phenotype.7 For example, HGC indivi­ duals exhibited an enrichment of genes associ­ated with a higher production of speci­ fic metabolites, such as SCFAs, and a higher hydro­gen production potential than LGC indivi­duals. Conversely, a shift towards sul­ phatereductionwassuggestedinthosewithan LGC. These results were associated with specific phylogenetic or functional signals, suggesting a shift between specific bac­ terial species (for example, Faecalibacterium prausnitzii and Akkermansia muciniphila) or metabolic functions (for example, produc­ tion of butyrate, mucus, CH4 and H2 ). These factors might be associated with a protec­ tive role of the gut barrier against bacteria, such as Ruminococcus torques and Campylo­ bacter, and processes involved in alterations in the gut barrier (for example, increased H2 S and mucus degradation; Figure 1). Finally, the signatures of unknown species that were associated with HGC or LGC were also identified.7 Although based on a model proposed fol­ lowing a different genetic signal, these data are in perfect accordance with previous results obtained in rodents.8,9 These studies had suggested a role for the gut microbiota and specific metabolites in gut-barrier func­ tion and in the development of inflammation in obesity and T2DM. One of the common denominators of the studies presented here is the observa­ tion that some bacterial metabolites, such as the levels of SCFAs, and/or some genera of bacteria (for example, Akkermansia) have a key role in regulating various disease states (Figure 1). Along these lines, my group has demonstrated that A. muciniphila was decreased in obese and type 2 diabetic mice, and that administration of A. mucini­phila partially protects mice against diet-induced obesity, insulin resistance, metabolic inflam­ mation and gut-barrier dysfunction.9 Pre­ biotics (that is, oligofructose) are a useful tool to increase the intestinal abundance of this microbe.8,9 Of note, Akkermansia is a pro­pionate producer, and SCFAs have been shown to link gut microbiota with host metabolism.10 Hence, although the link might not be obvious, the findings of these studies are clearly intertwined. Overall, these reports suggest that key com­mon mechanisms underlie both the suc­cess of gastric bypass surgery and the dis­ cordant gut microbiota observed in indivi­ duals with obesity and T2DM (that is, with respect to gene richness and capacity to induce an obese phenotype) and that key metabolites, such as SCFAs, are involved. The next challenge will be to determine whether specific bacterial groups or their micro­ bial activities can be harnessed for future therapeut­ic st­rategies in humans. Université Catholique de Louvain, LDRI, Metabolism and Nutrition research group, WELBIO,Avenue E. Mounier, 73 box B1.73.11, B‑1200 Brussels, Belgium. patrice.cani@uclouvain.be Acknowledgements P. D. Cani is a research associate from the FRS- FNRS (Fonds de la Recherche Scientifique) and a Key advances ■■ Alterations in the gut microbiota resulting from gastric bypass have a major role in host metabolism4 ■■ Functional and metabolic activities of the gut microbiota regulate metabolism5–7 ■■ Increased intestinal SCFA production and the presence of Akkermansia are associated with reduced obesity, insulin resistance, inflammation and an improved gut-barrier function4,5,7,9 recipient of grants from the FNRS and FRSM (Fonds de la recherche scientifique médicale), Belgium, and of the European Research Council starting grant 2013 (336452-ENIGMO). Competing interests The author declares no competing interests. 1. Zhao, L. The gut microbiota and obesity: from correlation to causality. Nat. Rev. Microbiol. 11, 639–647 (2013). 2. Turnbaugh, P. J. et al. An obesity-associated gut microbiome with increased capacity for energy harvest. Nature 444, 1027–1031 (2006). 3. Zhang, H. et al. Human gut microbiota in obesity and after gastric bypass. Proc. Natl Acad. Sci. USA 106, 2365–2370 (2009). 4. Liou, A. P. et al. Conserved shifts in the gut microbiota due to gastric bypass reduce host weight and adiposity. Sci.Transl. Med. 5, 178ra41 (2013). 5. Ridaura, V. K. et al. Gut microbiota from twins discordant for obesity modulate metabolism in mice. Science 341, 1241214 (2013). 6. Cotillard, A. et al. Dietary intervention impact on gut microbial gene richness. Nature 500, 585–588 (2013). 7. Le Chatelier, E. et al. Richness of human gut microbiome correlates with metabolic markers. Nature 500, 541–546 (2013). 8. Everard, A. et al. Responses of gut microbiota and glucose and lipid metabolism to prebiotics in genetic obese and diet-induced leptin- resistant mice. Diabetes 60, 2775–2786 (2011). 9. Everard, A. et al. Cross-talk between Akkermansia muciniphila and intestinal epithelium controls diet-induced obesity. Proc. Natl Acad. Sci. USA 110, 9066–9071 (2013). 10. Kimura, I. et al. The gut microbiota suppresses insulin-mediated fat accumulation via the short- chain fatty acid receptor GPR43. Nat. Commun. 4, 1829 (2013). ADRENAL CANCER IN 2013 Time to individualize treatment for adrenocortical cancer? Constantine A. Stratakis 2013 was a good year for adrenocortical cancer, as the new knowledge gained holds great promise for patients. Advances were made in genetics, epigenetics, the advent of related technological and bioinformatic tools, and the feasibility of massive screening of people and samples. Stratakis, C. A. Nat. Rev. Endocrinol. 10, 76–78 (2014); published online 7 January 2014; doi:10.1038/nrendo.2013.263 Adrenocortical cancer was one of the earliest neoplasms to be linked to a tumour suppres­ sor gene defect: the recognition that TP53 mutations were present both in the germline of patients with Li–Fraumeni syn­drome and in the somatic state in many sporadic­ally occurring adrenocortical cancers preceded the discovery that a low penetrance TP53 mutant allele, Arg337His, can predispose to both benign adreno­cortical adenoma and adreno­cortical cancer.1 How­ever, the early recognition of a classic tumour sup­ pressor gene being involved in adreno­ cortical cancer pathogenesis did not lead to significant advances in the treatment of this disorder, and it remains one of the least curable diseases, despite efforts in the past few years.2 The mainstay of treat­ ment remains surgery in early stages, fol­ lowed by mitotane as adjuvant therapy © 2014 Macmillan Publishers Limited. All rights reserved
  • 38. KEY ADVANCES IN MEDICINE JANUARY 2014  |  33 ENDOCRINOLOGY Figure 1 | Hyperplasia–adenoma–carcinoma sequence and molecular heterogeneity in adrenocortical cancer. Adrenocortical cancers may be formed (lower panel) by resident stem cells or tissue-specific pluripotent cells, as in other cancers. These cells differentiate and mature over time (upper panel), in the fetal and then adult adrenal cortex, leaving a small population of cells (blue colour) within the adrenal cortex capable of regeneration and healing. At any time, these pluripotent cells may become the origin of a benign (brown) or malignant (red) neoplasm, as shown by the multiple arrows, as a result of genetic (defects in PRKAR1A, CTNNB1 or the Arg337His TP53 mutation) or epigenetic alterations in these or other genes. Adrenocortical cancers can originate in early life (lower panel) without these cells ever differentiating (lower panel) or could form later in life from the residual stem cells in mature tissues (upper panel) from somatic mutations in genes, such as CTNNB1 and TP53 and others. Adrenocortical cancers (last collection of cells, lower panel) are heterogeneous bearing a variety of molecular signatures, as a result of the cumulative effect of a number of genetic or epigenetic hits in the IGF-2, Wnt and perhaps additional signalling pathways. Reprinted from Mol. Cell. Endocrinol. 371, Stratakis, C. A. cAMP/PKA signaling defects in tumors: genetics and tissue-specific pluripotential cell-derived lesions in human and mouse. 208–220. © (2013), with permission from Elsevier. Pluripotent cells Differentiated cells Adrenal cancer Normal adrenal cortex Differentiated cells Pluripotent cells Differentiated cellsTumour cells Stem cell and surgery and/or mitotane and some form of combination chemo­therapy (eto­ poside, doxo­rubicin and cisplatin, or st­reptozotocin) in advanced stages.2 Why did the initial discovery of TP53 not lead to more breakthroughs and molecu­ larly designed therapies in adrenocorti­ cal cancer? First, it was soon realized that TP53 mutations are present in many other types of neoplasms and it is a late event in tumour progression, its inactivation affect­ ing the cell cycle and genomic integrity. The cancer genome atlas analysis showed that TP53 was the most frequently mutated gene in the studied tumours, with 42% of the cancers carrying a mutant TP53 allele.3 Second, adrenocortical cancer is a rare tumour, making the study of its progres­ sion difficult. As early as 2003, the sugges­ tion was made that adrenocortical cancer is not different from other solid tumours in terms of its formation and progression,4 but lack of access to samples in which the hyperplasia–adenoma–carcinoma sequence (Figure 1) was evident impeded further investigation of this hypothesis. In other tumours, such as colon cancer, much of what we know today (and the treatments applied) relied on the findings of investiga­ tions of the hyperplastic polyp–adenoma– carcinoma sequence and the respective molecular pathways. Along these lines, the adrenocortical cancer investigations clung too long to the clonality dogma, which stated that cancer represented the expan­ sion of an identical and monoclonal aggres­ sive cell population. The notion that cancer is a disease propagated by a single cell clone was debunked in many tumours in the past few years,5 but only in 2013 has it become apparent that adrenocortical cancer, too, is as heterogenous as any other tumour. Third, similar to other cancers, targeting of a number of molecular pathway altera­ tions in adrenocortical cancer did not trans­late into successful therapies; the best example is the targeting of the insulin-like growth factor 1 and insulin-like growth factor 2 pathways.6 Finally, the possibility that adrenocortical cancer develops from tissue-specific, adrenal-cortex-residing or adrenal-cortex-derived, pluripotent or stem cells has not quite been accepted in the field as it has been for other tumours.5 Knowledge obtained in 2013 may change these obstructive factors in our fight against adrenocortical cancer, to the benefit of patients. The hypo­thesis of an adenoma– carcinoma sequence in adreno­cortical cancer was tested in 2013 by Custodio et al.7 who preclinically detected carriers of the most frequent low penetrance TP53 mutant allele, Arg337His. In this first ever study of newborn genetic screening for a cancer- predisposing genetic defect, 171,649 new­ borns in the state of Parana, Brazil, where this mutation is particularly frequent,1 were screened between 2005 and 2010. A total of 461 infants carried the Arg337His allele (0.27%) and 11 of them developed a tumour in the course of the study versus only two from the remaining 171,188 chil­ dren. One patient had a benign adreno­ cortical adenoma at surgery but most had small, stage I cancer. The implications of this study are far- reaching and beyond the scope of this article. The answers to questions, includ­ ing whether we should screen newborns for tumour-predisposing genetic variants, what the costs are to society and public- health agencies, and what the emotional impact is on affected children and their families, remain to be debated. For now, I focus on what is clearly a first and the fact that this prospective study seems to confirm a hypothesis generated 12 years previously:1 adrenocortical cancer is progressive (and, if detected early, can be cured), and at least in some cases it may form from a pre-existing adrenocortical adenoma or hyperplasia caused by the same genetic defect. In other words, the findings of Custodio et al.7 implicate an adenoma–carcinoma sequence in adrenocortical cancer, and this process was elegantly further supported by a single nucleotide polymorphism (SNP) array study that was published in 2013.8 Ronchi et al.8 showed that malignant tumours have more genomic aberrations than benign ones. The SNP array findings also confirmed the involvement of IGF2 in advanced adreno­ cortical cancer and showed the hetero­geneity of the samples studied. Gene network analy­ sis by Ronchi et al.8 identified Wnt signalling as the most relevant network in adreno­ cortical cancer, indicated by the involve­ ment of WNT5A signalling and many related genes (APC2, AXIN1, NKD2 and others) in adreno­cortical cancer. © 2014 Macmillan Publishers Limited. All rights reserved
  • 39. 34  |  JANUARY 2014 www.nature.com/reviews ENDOCRINOLOGY In 2013, Gaujoux et al.9 also reported a role of Wnt signalling in adrenocortical cancer. In this study, silencing β‑catenin (encoded by the CTNNB1 gene) in an adreno­cortical cancer cell line (H295R) and in mouse xenografts inhibited proliferation and increased apoptosis of the cancer cells. Evidence from this study and several others suggest that dysregulation of the β‑catenin pathway and Wnt signalling could lead to tumour formation or progression in adreno­cortical cancer from, possibly, resi­ dent stem cells (Figure 1). The importance of the β‑catenin pathway in maintaining stem cells capable for tumour formation in many tissues is well-known.5,6,9 These studies suggest that Wnt signalling inhibitors could be used in the treatment of adreno­cortical cancer. Will they succeed? The 2013 study by De Martino et al.10 could help in answer­ ing this question by bringing us back to the genetic investigations and the issue of heterogeneity in cancer,5 and in adreno­ cortical cancer in particular. De Martino and co-workers10 sought targetable molecu­ lar events in a number of tumours in a study similar but more clinically focused than that of Ronchi and colleagues. The conclusion is that for any drug therapy to succeed it will have to be applied after the molecular signature of the adrenocortical cancer of the indivi­dual patient is characterized at the genetic and epigenetic level. This conclusion mirrors what is already happening today in breast, colon and prostate cancer, but has yet to be applied in ad­renocortical cancer. In conclusion, a number of key papers in adrenal cancer were published in 2013. The evidence for an adenoma–carcinoma sequence amassed in 20138 reminds us of the age-tested motto veritas temporis filia and points to the impact of screening neonates for a cancer-causing defect and its associated huge implications.7 Lastly, the pathway and heterogeneity ana­lyses9,10 could lead to new drug treatments. These advances are only good news for our patients! Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), CRC Room 1‑3330, East Laboratories, Building 10‑CRC, 10 Center Drive, SEGEN/PDEGEN, NICHD, NIH, Bethesda, MD 20892, USA. stratakc@mail.nih.gov Key advances ■■ The first ever newborn screening for a cancer-predisposing genetic defect preclinically identified adrenocortical cancer in infants in the state of Parana, Brazil7 ■■ An adenoma–carcinoma sequence is suggested by genome-wide studies of benign and malignant adrenal tumours that showed more genetic alterations in the latter than in the former8 ■■ Silencing β‑catenin in adrenocortical cancer cells leads to inhibition of their proliferation and increased apoptosis9 ■■ A genetic screen confirms significant heterogeneity within adrenocortical cancer and points to the need for individualized treatment for patients with adrenocortical cancer based on their molecular signature10 Acknowledgements The author’s work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD). Competing interests The author declares no competing interests. 1. Ribeiro, R. C. et al. An inherited p53 mutation that contributes in a tissue-specific manner to pediatric adrenal cortical carcinoma. Proc. Natl Acad. Sci. USA 98, 9330–9335 (2001). 2. Fassnacht, M. et al. Combination chemotherapy in advanced adrenocortical carcinoma. N. Engl. J. Med. 366, 2189–2197 (2012). 3. Kandoth, C. et al. Mutational landscape and significance across 12 major cancer types. Nature 502, 333–339 (2013). 4. Stratakis, C. A. Genetics of adrenocortical tumors: gatekeepers, landscapers and conductors in symphony. Trends Endocrinol. Metab. 14, 404–410 (2003). 5. Marjanovic, N. D., Weinberg, R. A. & Chaffer, C. L. Cell plasticity and heterogeneity in cancer. Clin. Chem. 59, 168–179 (2013). 6. Drelon, C., Berthon, A. & Val, P. Adrenocortical cancer and IGF2: is the game over or our experimental models limited? J. Clin. Endocrinol. Metab. 98, 505–507 (2013). 7. Custódio, G. et al. Impact of neonatal screening and surveillance for the TP53 R337H mutation on early detection of childhood adrenocortical tumors. J. Clin. Oncol. 31, 2619–2626 (2013). 8. Ronchi, C. L. et al. Single nucleotide polymorphism array profiling of adrenocortical tumors - evidence for an adenoma carcinoma sequence? PLoS ONE 8, e73959 (2013). 9. Gaujoux, S. et al. Silencing mutated β-catenin inhibits cell proliferation and stimulates apoptosis in the adrenocortical cancer cell line H295R. PLoS ONE 8, e55743 (2013). 10. De Martino, M. C. et al. Molecular screening for a personalized treatment approach in advanced adrenocortical cancer. J. Clin. Endocrinol. Metab. 98, 4080–4088 (2013). © 2014 Macmillan Publishers Limited. All rights reserved
  • 40. Editors’ picks of the year Global obesity: trends, risk factors and policy implications Vasanti S. Malik, Walter C. Willett and Frank B. Hu Owing to the scope and complexity of the obesity epidemic, prevention strategies and policies across multiple levels are needed in order to have a measurable effect. The authors discuss global trends in obesity prevalence and population-based interventions, and make broad policy recommendations for obesity and chronic disease prevention. doi:10.1038/nrendo.2012.199 Role of KCNJ5 in familial and sporadic primary aldosteronism Paolo Mulatero, Silvia Monticone, William E. Rainey, Franco Veglio and Tracy Ann Williams Mutations in the GIRK4 potassium channel are associated with both sporadic aldosterone-producing adenomas and familial hyperaldosteronism type III. This Review discusses the pathophysiological role of GIRK4 in sporadic and genetic hyperaldosteronism and the molecular alterations associated with channel dysfunction. doi:10.1038/nrendo.2012.230 Immune therapy in type 1 diabetes mellitus Åke Lernmark & Helena Elding Larsson Immune therapy for type 1 diabetes mellitus can be approached at three different stages: primary prevention, secondary prevention and intervention. This Review discusses the different types of immune therapies being attempted at these three different stages and the findings of completed and ongoing trials of these therapies. doi:10.1038/nrendo.2012.237 Growth hormone and cognitive function Fred Nyberg and Mathias Hallberg In humans, growth hormone (GH) has major effects on brain function. Fred Nyberg and Mathias Hallberg outline the mechanisms that underlie the interactions between GH and the central nervous system. The role of GH as a treatment for patients with cognitive impairment owing to GH deficiency is also discussed. doi:10.1038/nrendo.2013.78 The endocrinology of food intake Denovan P. Begg and Stephen C. Woods When, what and how much to eat are complex processes that are influenced by many different factors. In this Review, the authors discuss how the endocrine system influences eating and outline the roles of satiation hormones, adiposity hormones and regulatory hormones. doi:10.1038/nrendo.2013.136 Increasing incidence of thyroid cancer: controversies explored Yasuhiro Ito,Yuri E. Nikiforov, Martin Schlumberger and Riccardo Vigneri In this Viewpoint article, experts from the field of thyroid cancer discuss and offer insight into the controversy surrounding the changing trends in thyroid cancer incidence. doi:10.1038/nrendo.2012.257 Fertility preservation in women Jacques Donnez and Marie-Madeleine Dolmans Advances in cancer therapy over the past two decades have resulted in more patients surviving for longer after treatment. As many therapies can cause premature ovarian failure (POF), infertility in female cancer patients now needs to be addressed. This Review analyses the options that are currently available to preserve fertility in female patients with cancer and in women at risk of POF. doi:10.1038/nrendo.2013.205 Oxidative stress and the ageing endocrine system Giovanni Vitale, Stefano Salvioli and Claudio Franceschi A progressive decline in cellular function and organismal fitness and an increase in age-related diseases are associated with ageing; many theories have attempted to explain this phenomenon. This Review outlines the current knowledge of the effects of oxidative stress on endocrine organs and tissues and suggests that inflammation is the link between oxidative stress and ageing. doi:10.1038/nrendo.2013.29 Wnt signalling in osteoporosis: mechanisms and novel therapeutic approaches Ernesto Canalis Wnt signalling is crucial for bone formation, as mutations in this pathway can lead to skeletal disorders. This Review summarizes current studies on Wnt signalling and advances in therapeutic approaches targeting Wnt antagonists to enhance bone formation. doi:10.1038/nrendo.2013.154 Type 2 diabetes mellitus—an autoimmune disease? Lício A. Velloso, Decio L. Eizirik and Miriam Cnop Emerging data suggest a role for autoimmunity in type 2 diabetes mellitus (T2DM). In this Perspectives, the authors discuss the nature of the immune response in diabetes mellitus and the evidence for an autoimmune component in T2DM and obesity. doi:10.1038/nrendo.2013.131 February 2014 volume 10 no. 2 www.nature.com/reviews THYROID NEOPLASIAS Deregulation of microRNA expression in thyroid carcinogenesis Congenital adrenal hyperplasia Treatment and health outcomes in adult patients ENDOCRINOLOGY nrendo_OFC_FEB14.indd 1 07/01/2014 15:32 * * * * * * * * * * A selection of articles published during 2013 in Nature Reviews Endocrinology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Endocrinology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 41. GASTROENTEROLOGY & HEPATOLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  35 HEPATITIS C IN 2013 HCV causes systemic disorders that can be cured Francesco Negro Successful treatment with antivirals reduces the incidence of some extrahepatic manifestations of HCV. Thus, the advent of well-tolerated and highly potent antiviral regimens might enable extension of the indication for therapy to patients at risk of developing serious extrahepatic disorders, irrespective of the severity of the underlying liver disease. Negro, F. Nat. Rev. Gastroenterol. Hepatol. 11, 77–78 (2014); published online 26 November 2013; doi:10.1038/nrgastro.2013.222 In 2013, an estimated 185 million people globally are thought to be infected with HCV.1 The morbidity and mortality associ- ated with hepatitis C are mostly attributable to cirrhosis and hepatocellular carcinoma (HCC), which are the leading indications for liver transplantation in most Western countries.1 However, HCV also has effects beyond the liver; it has consistently been shown that HCV affects the function and integrity of several extrahepatic organs and tissues, leading to a variety of clini- cal manifestations.2 These extrahepatic disorders include cryoglobulinaemia (character­ized by cutaneous vasculitis and glomerulonephritis); non-Hodgkin B‑cell lymphoma; insulin resistance (which leads to overt type 2 diabetes and its renal and cardiovascular consequences); polyarthritis (which mimics rheumatoid arthritis); and several neuropathological changes ranging from cognitive impairment to depression (Figure 1). The pathogenesis of these fea- tures might be directly or indirectly related to HCV infection. For example, dysfunc- tions of the central nervous system might be secondary to a severe liver functional impairment, but also might be attribut- able to the direct infection of brain tissue with HCV. This hypothesis is supported by the discovery at the end of 2012 that endothelial cells in the brain express func- tional receptors that support HCV entry and replication, which leads to apopto- sis.3 For insulin resistance, it seems plaus­ ible that infected hepatocytes may secrete (yet to be identified) soluble substances that are capable of affecting distant, meta- bolically active cells, such as adipocytes and myocytes.4 Independent of their pathogenesis, the extrahepatic manifestations of HCV not only have a considerable effect on the patients’ quality of life and the HCV-related public health burden, but are often a chal- lenge to manage effectively. For example, the extrahepatic manifestation could be an out- right contraindication for antiviral therapy, especially IFNα. The emergence of com- binations of direct-acting anti­virals with improved tolerability might ease the exist- ing barriers to viral eradication, although safety concerns and drug–drug interactions might still be issues, especially in patients with comorbidities. In addition, although cure of HCV infection is associated with decreased all-cause and liver-related mor- bidity and mortality,5 the effects of success- ful antiviral therapy on specific extrahepatic disorders has been studied in less detail. It is particularly interesting that several papers published in 2013 have addressed the asso- ciation of HCV infection with metabolic and cardiovascular manifest­ations, and how antiviral therapy might affect their most serious complications. One study published in 2013 analysed data from patients with HCV infection in the National Health and Nutrition Examination Survey (NHANES) database.6 The data considered in this study included: BMI; waist circumference; blood pressure; alcohol consumption; smoking history; fasting serum levels of glucose and insulin; and the serum lipid profile. Of 19,741 e­ligible individuals, 173 (0.88%) tested positive for HCV; 19,568 had no evidence of chronic liver disease and were used as controls. The study confirmed historical data from the NHANES on the association of hepatitis C with insulin resistance and type 2 diabetes. In addition, HCV infection was found to be independently associated with hypertension and, even more inter- estingly, congestive heart failure (OR 2.49, 95% CI, 1.04–5.96) after controlling for age, obesity and smoking. The authors specu- lated that the known glucose metabolic dis- turbances induced by HCV might act as a potential pathogenetic factor leading to the poor cardio­vascular o­utcomes associated with HCV infection. Figure 1 | A non-exhaustive list of extrahepatic manifestations that have been associated with HCV infection. Mixed cryoglobulinaemia Membranoproliferative glomerulonephritis Cognitive impairment Fibromyalgia syndrome Mooren-type ulcerative keratitis Polyarthritis Sicca syndrome Myocardial dysfunction Insulin resistance and/or type 2 diabetes Non-Hodgkin B-cell lymphoma Extrahepatic disorders associated with HCV infection © 2014 Macmillan Publishers Limited. All rights reserved
  • 42. S36 www.nature.com/nrgastro/collections/xxxx36  |  JANUARY 2014 www.nature.com/reviews GASTROENTEROLOGY & HEPATOLOGY A separate study compared the Fram­ ingham Risk Score (a well-known prognostic algorithm that is used to estimate the 10-year cardiovascular risk of an indi- vidual) and the vascular age differences in patients with HCV infection, HIV infec- tion, co-infection with HIV and HCV and in a sample of the general population ran- domly selected from the NHANES database and matched for sex, ethnicity and age.7 After controlling for weight, marital status, ongoing therapy and the abovementioned matching variables, patients with HCV had a 2.4% higher general Framingham Risk Score and vascular age differences 4.4 years greater (P <0.001) than the general popu- lation (P <0.001). Patients with co-infec- tion with HIV and HCV had a 2% higher general Framingham Risk Score and vas- cular age differences 4.1 years greater than the control individuals. However, as the cardiovascular risk was not statistically sig- nificantly different between patients with HIV and the general population, the differ- ence observed in patients with co-infection could be mostly due to HCV. A retrospective, general-population- based cohort study published in 2013 a­naly­sed the incidence of stroke in a random sample from the Taiwan National Health Insurance Program database.8 The study included 3,113 patients with HCV and 12,452 un­infected control individ­uals. A subgroup included 208 patients with HCV who had undergone an antiviral treat- ment course of at least 3 months. Patient character­istics were comparable between the two groups, apart from the treated patients being younger, with a lower incidence of diabetes, aspirin use and angiotensin con- verting enzyme inhibitor use than untreated patients. HCV infection was associated with a 23% increased risk of stroke after adjust- ing for known prognostic factors, including hyperlipidaemia, diabetes, ischaemic heart diseases, alcohol-related diseases, aspirin use, statin use and influenza vaccination (adjusted HR = 1.23, 95% CI, 1.06–1.43, P = 0.006). The results remained unchanged even after adjusting for all confounders (adjusted HR = 1.23, 95% CI, 1.06–1.42, P = 0.008). Interestingly, antiviral treatment led to a significant decrease in the risk of stroke (adjusted HR = 0.38, 95% CI, 0.16– 0.93, P = 0.033) after adjusting for known prognostic factors that differed considerably between the two cohorts, including age, dia- betes, aspirin use and use of an angio­tensin converting enzyme inhibitor. The beneficial effect of treatment is particularly intrigu- ing, as it provides strong evidence in favour of a pathogenic role for HCV in c­erebral v­ascular diseases. In a prospective cohort study,9 again from Taiwan, 1,411 patients with diabetes and HCV infection who were treated with anti- virals were enrolled and matched by propen- sity scores with 1,411 patients with diabetes and HCV infection who were untreated con- trols. The treated cohort was also matched with 5,644 patients with diabetes but not HCV. The difference in the 8‑year (2003– 2011) cumulative incidence of end-stage renal disease in the treated, untreated and uninfected cohorts was highly significant, that is, 1.1%, 9.3% and 3.3%, respectively (P <0.001). Differences in the occurrence of incident stroke were less impressive (3.1%. 5.3% and 6.1%, respectively) but were still significant (P = 0.01); and those for acute coronary syndrome were at the limit of stat­ istical significance (4.1%, 6.6%, and 7.4%, respectively, P = 0.05). Compared with the untreated cohort, antiviral treatment was associated with multivariate-adjusted, sig- nificantly reduced risk of end-stage renal disease (HR = 0.16; 95% CI, 0.07–0.33%) and of ischaemic stroke (HR = 0.53; 95% CI, 0.30–0.93). These findings indicate that anti- viral treatment for HCV infection improves renal and cardiovascular outcomes in patients who also have diabetes. Thus, based on the above studies as well as previous data,10 increasing evi- dence supports the fact that a portion of the morbidity and the mortality related to HCV infection depends on its extra­ hepatic manifestations, and that successful antiviral therapy might reduce both. This finding has important consequences, and not only for cost-effectivenes­s analyses. A major paradigm shift could occur that would involve extending the indication for antiviral therapy not only on the basis of the severity of the HCV-associated liver disease, but also on the risk of developing serious extrahepatic, systemic disorders with potentially fatal outcomes. Some sub- groups of patients with hepatitis C, such as those who also have severe insulin resist- ance, or type 2 diabetes, or those who are obese and >60 years old might benefit from antiviral therapy irrespective of their hepa- titis C disease stage. Although more data are needed for proper risk stratification, the advent of well-tolerated and highly potent antiviral regimens might facilitate these therapeutic decisions in severely ill patients with hepatitis C and comorbidities. Divisions of Gastroenterology and Hepatology and of Clinical Pathology, University Hospitals, Rue Gabrielle-Perret-Gentil 4, 1211 Geneva 14, Switzerland. francesco.negro@hcuge.ch Competing interests The author declares associations with the following companies: Boehringer Ingelheim, Gilead, Janssen, MSD, Novartis and Roche. Please see the article online for full details of the relationships. 1. Thomas, D. L. Global control of hepatitis C: where challenge meets opportunity. Nat. Med. 19, 850–858 (2013). 2. Jacobson, I. M., Cacoub, P., Dal Maso, L., Harrison, S. A. & Younossi, Z. M. Manifestations of chronic hepatitis C virus infection beyond the liver. Clin. Gastroenterol. Hepatol. 8, 1017–1029 (2010). 3. Fletcher, N. F. et al. Hepatitis C virus infects the endothelial cells of the blood–brain barrier. Gastroenterology 142, 634–643 (2012). 4. Vanni, E. et al. Sites and mechanisms of insulin resistance in nonobese, nondiabetic patients with chronic hepatitis C. Hepatology 50, 697–706 (2009). 5. van der Meer, A. J. et al. Association between sustained virological response and all-cause mortality among patients with chronic hepatitis C and advanced hepatic fibrosis. JAMA 308, 2584–2593 (2012). 6. Younossi, Z. M., Stepanova, M., Nader, F., Younossi, Z. & Elsheikh, E. Associations of chronic hepatitis C with metabolic and cardiac outcomes. Aliment. Pharmacol.Ther. 37, 647–652 (2013). 7. Kakinami, L. et al. Risk of cardiovascular disease in HIV, hepatitis C, or HIV/hepatitis C patients compared to the general population. Int. J. Clin. Pract. 67, 6–13 (2013). 8. Hsu, C. S. et al. Interferon-based therapy reduces risk of stroke in chronic hepatitis C patients: a population-based cohort study in Taiwan. Aliment. Pharmacol.Ther. 38, 415–423 (2013). 9. Hsu, Y. C. et al. Antiviral treatment for hepatitis C virus infection is associated with improved renal and cardiovascular outcomes in diabetic patients. Hepatology http://dx.doi.org/ 10.1002/hep.26892. 10. Arase, Y. et al. Sustained virological response reduces incidence of onset of type 2 diabetes in chronic hepatitis C. Hepatology 49, 739–744 (2009). Key advances ■■ HCV is known to cause several extrahepatic manifestations, including stroke, cardiac failure and end-stage renal disease6–9 ■■ Treatment with antivirals reduces the incidence of some serious extrahepatic disorders associated with HCV8,9 ■■ The advent of well-tolerated and highly potent antivirals should open the debate about extending the indication for antiviral therapy8,9 ■■ This debate would not only be based on the severity of the HCV-associated liver disease, but also on the risk of developing serious extrahepatic, systemic disorders with potentially fatal outcomes6–9 © 2014 Macmillan Publishers Limited. All rights reserved
  • 43. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SBKEY ADVANCES IN MEDICINE JANUARY 2014  |  37 GASTROENTEROLOGY & HEPATOLOGY FAECAL MICROBIOTA TRANSPLANTATION IN 2013 Developing human gut microbiota as a class of therapeutics Alexander Khoruts Although the idea of faecal transplantation dates back many decades, only with advances in scientific technologies can we begin systematic development of this new class of therapeutics. The primary focus remains on treatment of Clostridium difficile infection—new applications are beginning to emerge, but a long journey remains ahead. Khoruts, A. Nat. Rev. Gastroenterol. Hepatol. 11, 79–80 (2014); published online 3 December 2013; doi:10.1038/nrgastro.2013.231 In their pioneering report, published in 1958, of the successful use of faecal enemas for the treatment of pseudomembranous enterocolitis, Eiseman and colleagues advo- cated a need for “more extensive clinical evaluation” of this “simple yet rational ther- apeutic method” and anticipated emergence of next-generation microbiota therapeutics in the form of “more precise bacterial, viral, or bacteriophage s­ubstitution therapy”.1 Unfortunately, Dr Eiseman passed away late in 2012, just before the publication in January 2013 of the first randomized, controlled trial comparing faecal micro- biota transplantation (FMT) with stand- ard vanco­mycin therapy for the treatment of recurrent Clostridium difficile infection (CDI).2 The study was terminated with less than half the patients enrolled because of clear superiority of FMT. In 1958, the organism responsible for pseudomembranous colitis was thought to be Micrococcus pyogenes, a gram-positive coccus (at the time grouped together with staphylococci). The Eiseman team seemed frustrated that M. pyogenes could not always be cultured from patients with pseudo­ membranous colitis, could not cause disease in any of the attempted animal models and could not colonize healthy human volun- teers. In retrospect, it is possible that the culprit organism was, in fact, C. difficile. Nevertheless, the focus on a Gram-positive pathogen facilitated the introduction of vancomycin in 1959 as an effective treat- ment for pseudomembranous colitis, whilst FMT retreated to merely anecdotal use, spor­adically reported and providing amusing reading for a number of decades. The C. difficile epidemic that has grown during the past decade is anything but amusing. Infections with new hyper­virulent strains, characterized by greater toxicity and sporulation efficiency are responsible for greater incidence, morbidity and mortality associated with CDI than ever before. Several studies published in 2013 used whole-genome sequencing to provide new insights into the biology of this formidable pathogen. He et al.3 analysed nearly 300 fluoroquinolone-resistant C. difficile iso- lates from patients worldwide. They found two distinct lineages (FQR1 and FQR2) of the 027/BI/NAP1 C. difficile that originated separately in North America and rapidly disseminated across the globe.3 Interest­ ingly, nearly all isolates of the two lineages shared insertion of a common conjugative t­ransposon into the same genomic location. Clearly, rapid evolutionary potential enabled by a wide range of mobile genetic elements carried by C. difficile combined with antibiotic pressures in the age of global human interconnectivity comprise a d­angerous recipe. The marked increase in the use of quinolone antibiotics in the late 1990s and early 2000s is unlikely to have been merely coincidental with the appear- ance of these hypervirulent strains. Eyre et al.4 used whole-genome sequencing to better understand mechanisms of transmis- sion of C. d­ifficile. They found that only 35% of isolates were genetically related to at least one other previous case to make it plausibly consistent with patient-to-patient transmis- sion. Furthermore, only half of these geneti- cally linked cases shared hospital-wide contacts. Thus, the majority of primary C. difficile infections in this population were acquired from poorly characterized reservoirs, such as asymptomatic carriers or environmental contamination. Importantly, the study does not negate the importance of current hospital infection control pro- grammes, already in place during the study, and might even support their effectiveness; it does demonstrate the need for additional work for better understanding of sources and transmission of C. difficile, which are essential for a­dequate control. The case study of C. difficile highlights the importance of considering the health of the commensal microbiota when trying to eradicate a specific pathogen. Patients with recurrent CDI can become caught in an endless cycle of infection recurrences that are perpetuated by repeated a­ntibiotic treat- ments. FMT repairs a­ntibiotic-induced disruption of the normal microbial com- munities.2 Clinically, FMT is typically s­pectacularly effective in treating even the most refractory cases. However, many prac- tical challenges need to be overcome before FMT can become mainstream practice in medicine, including: aesthetic consider­ ations; unstand­ardized donor selection and mater­ial preparation protocols; and poor reimbursement, at least in the USA. For now, faced with little alternative, the FDA is allowing use of FMT in its various current forms as practiced by individual physi- cians to treat CDI not responding to stand- ard therapies, even though FMT remains an unapproved ‘drug’. This approach is likely to last until next-generation micro- biota ­therapeutics are developed, tested and become widely available. One approach to overcome some of the challenges with FMT, anticipated by Eiseman’s group and sometimes success- fully achieved in the past,5 is to use culti- vated microbes. A serious obstacle for this approach is difficulty in growing most gut microbes in vitro. Using novel culture techniques that incorporate principles of microbial ecology, Petrof and colleagues6 constructed a system of 33 strains of bac­ teria isolated from the stool of a healthy individual. The mixture—selected for presumed safety, taxonomic diversity and antibiotic sensitivity—demonstrated com- munity robustness when grown in an anaerobic bioreactor designed to mimic conditions in the distal gut. The synthetic mixture was used to successfully treat two patients with recurrent CDI. Interestingly, donor DNA sequences were rare before treatment, but they comprised 50–70% of the total sequences during the first 2 weeks after treatment and decreased to 25% 6 months after treatment in the recipient faecal samples. This result suggests that the mixture might have served as scaffolding to reconstitute a more diverse distal gut m­icrobial c­ommunity. NPG © 2014 Macmillan Publishers Limited. All rights reserved
  • 44. S38 www.nature.com/nrgastro/collections/xxxx38  |  JANUARY 2014 www.nature.com/reviews GASTROENTEROLOGY & HEPATOLOGY Success of FMT in refractory CDI and multiple anecdotal reports in non-CDI dis- eases have emboldened many to consider this treatment option in other conditions asso- ciated with altered composition of the gut microbiota, including metabolic syndrome, IBD, IBS, and even autism.7,8 This year, we have seen the emergence of initial systematic trials that are critically needed to test these ideas. For instance, Kunde et al.9 reported a pilot trial of FMT in paediatric patients with ulcerative colitis; no serious adverse events were noted and, encouragingly, most patients experienced general improvement in symptomatic colitis. However, in a dif- ferent study of five adults with moderately- to-severely active ulcerative colitis, transient systemic toxicity (characterized by fever and increased levels of inflammatory markers) was observed.10 Ultimately, in this study,10 only one patient seems to have potentially benefited from the procedure; interestingly, clinical improvement was accompanied by augmentation of certain donor-derived phylotypes associated with anti-infammator­y properties. Clearly, a great deal of work needs to be done on defining optimal donor microbiota, as well as recipient selection and ­pre-treatment conditioning. We are in the infancy of the new science of host–microbeinteractioninthehumanbody. That the gut microbiota is a true organ with multiplefunctionsintegraltohumanphysiol- ogy, including energy and drug metabolism, gut motility, and development of the immune system and the nervous system, is now rec- ognized. Decades of liberal use of anti­biotics and altered nutrition without concern for their effects on gut microbiota could have contributed to the epidemic increase of many, once rare, diseases. Even our initial victory over CDI, a problem clearly caused by antibiotics that we treated with more anti- biotics, has proven to be short-lived. FMT has re-emerged over the past several years as a desperate measure in a losing battle. However, this time, FMT is accompanied by newtechnologiesthatenablecharacterization of the gut microbiota in terms of composition and function. In the next several years, an entirely new class of therapeutics composed of human microbiota will probably emerge. This class of agents could contain stand- ardized full-spectrum microbiota derived from human donors based on the principles of transplant medicine. We will probably also see various novel synthetic mixtures of microbiota; the two approaches might also be combined. Not only will these therapeutics help many patients, they will also have critical roles in advancing the science of micro­biota research and microbe–host interactions. This approach is the clearest path in moving beyond provocative association studies toward defining causal links between micro- biota, disease and health. Certainly, new regulatory paradigms will have to be created to accommodate current science. This time it is essential that the careful, systematic work that needs to be done is not interrupted for another half a century. University of Minnesota, Department of Medicine, Division of Gastroenterology and Centre for Immunology, 2101 6th Street S.E., Minneapolis, MN 55414, USA. khoru001@umn.edu Key advances ■■ Antibiotic pressures contributed to the emergence of hypervirulent Clostridium difficile strains that rapidly spread around the globe3 ■■ Hospital infection controls alone are insufficient to contain the C. difficile epidemic4 ■■ Faecal microbiota transplantation restores normal microbial gut ecology, and is superior to antibiotics in treating patients with recurrent C. difficile infection2 ■■ We should anticipate emergence of microbiota therapeutics as a new class of drugs to treat C. difficile infection and other conditions associated with microbial imbalance in the gut6,9,10 Competing interests The author declares an association with the following company: CIPAC LLC. See the article online for full details of the relationship. 1. Eiseman, B., Silen, W., Bascom, G. S. & Kauvar, A. J. Fecal enema as an adjunct in the treatment of pseudomembranous enterocolitis. Surgery 44, 854–859 (1958). 2. van Nood, E. et al. Duodenal infusion of donor feces for recurrent Clostridium difficile. N. Engl. J. Med. 368, 407–415 (2013). 3. He, M. et al. Emergence and global spread of epidemic healthcare-associated Clostridium difficile. Nat. Genet. 45, 109–113 (2013). 4. Eyre, D. W. et al. Diverse sources of C. difficile infection identified on whole-genome sequencing. N. Engl. J. Med. 369, 1195–1205 (2013). 5. Tvede, M. & Rask-Madsen, J. Bacteriotherapy for chronic relapsing Clostridium difficile diarrhoea in six patients. Lancet 1, 1156–1160 (1989). 6. Petrof, E. O. et al. Stool substitute transplant therapy for the eradication of Clostridium difficile infection: ‘RePOOPulating’ the gut. Microbiome 1, 1–12 (2013). 7. Aroniadis, O. C. & Brandt, L. J. Fecal microbiota transplantation: past, present and future. Curr. Opin. Gastroenterol. 29, 79–84 (2013). 8. Smits, L. P., Bouter, K. E., de Vos, W. M., Borody, T. J. & Nieuwdorp, M. Therapeutic potential of fecal microbiota transplantation. Gastroenterology 145, 946–953 (2013). 9. Kunde, S. et al. Safety, tolerability, and clinical response after fecal transplantation in children and young adults with ulcerative colitis. J. Pediatr. Gastroenterol. Nutr. 56, 597–601 (2013). 10. Angelberger, S. et al. Temporal bacterial community dynamics vary among ulcerative colitis patients after fecal microbiota transplantation. Am. J. Gastroenterol. 108, 1620–1630 (2013). COELIAC DISEASE IN 2013 New insights in dietary- gluten‑induced autoimmunity Katri Kaukinen and Markku Mäki Coeliac disease comprises intolerance against dietary wheat, rye and barley gluten and is one of the most common food-related life-long disorders in Western countries. In 2013, new knowledge of the clinical diversity of coeliac disease and further details about the autoimmune aspects of this disorder have emerged. Kaukinen, K. & Mäki, M. Nat. Rev. Gastroenterol. Hepatol. 11, 80–82 (2014); published online 10 December 2013; doi:10.1038/nrgastro.2013.232 Coeliacdiseaseisinmanywaysagoodmodel of an autoimmune disorder.1 The roles of the environmental trigger and driving force (dietary wheat gluten and related proteins in rye and barley), major histocompatibility class II susceptibility genes (alleles encoding HLA-DQ2 and HLA-DQ8 heterodimer mol- ecules) and self (transglutaminase 2 [TG2]) in the pathogenesis of the condition have all been identified. The key features of the disease are gluten-driven T‑cell-mediated destruction of specific cells and the devel- opment of disease-specific serum autoanti- bodies against TG2.1–3 These autoantibody biomarkers are becoming more widely used for case finding and screening; this strategy © 2014 Macmillan Publishers Limited. All rights reserved
  • 45. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SBKEY ADVANCES IN MEDICINE JANUARY 2014  |  39 GASTROENTEROLOGY & HEPATOLOGY has not only improved the diagnostic rate for coeliac disease, but positivity for these autoantibodies also indicates impending development of coeliac disease with a mani- fest small-bowel mucosal lesion.1 Recent studies have indicated that coeliac disease is a significant health problem; its world- wide prevalence has increased, with current estimates at 1% of the population.4 The frequency of the disease also varies greatly depending on location, but the factors that contribute to this variation are poorly understood. T cells have been at the centre of autoimmune disease pathology. In the past year, acknowledgement and advances in B-cell autoimmunity (triggered by an e­nvironmental insult) have been made. A follow-up of birth cohorts born during and after the Swedish coeliac disease ‘epi- demic’ (1984–1996) has given valuable insight into the environmental factors affect- ing its development.4 During the epidemic, the incidence of traditional symptomatic coeliac disease suddenly increased in young children. After the implementation of new infant feeding practices, the incidence of coeliac disease sharply declined, which sug- gested that introduction or large consump- tion of gluten after weaning predisposes an infant to the development of the disease.4 At 12 years of age, two birth cohorts born during (1993) or after (1997) the epidemic were screened for coeliac disease. By combining clinically detected and screen-identified cases it was possible to assess the true prevalence of the disease and to see whether infant feeding practices had affected disease occurrence after long-term follow-up. Interestingly, the prevalence of coeliac disease at the age of 12 years was as high as 2.9% in the 1993 cohort born and 2.2% in the 1997 cohort. Children born during 1997 had a significantly reduced risk of developing coeliac disease when com- pared with those born during 1993 (preva- lence ratio 0.75; 95% CI 0.60–0.93, P = 0.01). Of note, the proportion of infants who had gradual introduction of small amounts of glutenwhilebeingbreastfedwasc­onsiderably larger in the 1997 cohort.4 Breastfeeding influences the composition of the intestinal microbiota and protects against gastrointestinal infections. Evidence also suggests that dysbiosis in residential gut bacteria is a risk factor for coeliac dis­ ease, either by directly influencing immune responses in the mucosa or by enhanc- ing inflammatory responses to gluten.5 In infancy, the amount of gluten ingested after weaning and the early intraluminal ­environment might also contribute to the developmentoftheintestinalimmunesyst­em and oral tolerance.5 These observations offer an option for disease prevention and such intervention trials are already ongoing. Long- term follow-up is now needed to show any potential effect of making changes in infant feeding practices on adult-onset coeliac disease. Indeed, coeliac disease often goes undiagnosed and the need for earlier diag- nosis by screening programmes is advo- cated. However, whether truly asymptomatic patients with coeliac disease would benefit from screening and whether it would be c­ost‑effective remains unclear. Early observational studies suggested that maternal coeliac disease influences fetal development. Untreated coeliac disease has been associated with an increased risk of intrauterine growth retardation, preterm delivery and caesarean section, but when patients with coeliac disease are on a gluten- free diet, no such association with adverse fetal outcomes exists.2,6 When TG2 auto­ antibodies were screened for in 7,046 preg- nant women, the level of TG2 autoantibodies was found to be inversely associated with fetal growth and placental weight.6 Growth was reduced to the greatest extent in fetuses from women with the highest levels of TG2 autoantibodies, but intermediate antibody levels also had detrimental effects on fetal growth in mothers carrying coeliac-disease- type HLA-DQ2 or HLA-DQ8. These adverse outcomes were unrelated to the maternal nutritional status, and TG2 autoantibodies were suggested to independently influence placental development, its vasculature and function, leading to fetal growth restriction.6 In patients with untreated coeliac disease, the mucosal vasculature of the small bowel is altered and TG2 autoantibodies are deposited on the vessels, targeting endothelial TG2. In in vitro and in vivo models, TG2 autoanti- bodies are able to disturb angiogenesis and increasevascularpermeability.7 Furthermore, maternal coeliac antibodies transferred pas- sively into newborns alter the behaviour of endothelial cells of the umbilical cord and are associated with low neonatal birth-weight.2 TG2 autoantibodies deposited on the surface of chorionic villi might also alter TG2 activ- ity, cell adhesion and spreading, thus impair- ing placental function. Low birth-weight is thought to have long-term effects; it is associated with reduced neuropsychological performance later in life and development of diseases such as type 2 diabetes melli- tus and hypertension in adulthood.6 Early diagnosis and treatment of coeliac disease might prevent fetal growth restriction and its potential long-term complications. As such, the possibility of screening for coeliac disease in women of childbearing age needs to be evaluated. In 2013, studies on the mechanisms under- lying TG2-autoantibody formation in coeliac disease continued. Epitopes recognized by coeliac-disease-specific autoantibodies were shown to be conformational.2,8 In fact, the TG2-targeted autoautoantibodies were found to bind to a single three-amino-acid epitope exposedonTG2.2 Inthesamestudy,adistinct monoclonal antibody recognizing part of this coeliac epitope was found to antagonize the harmful effects of human autoantibodies in cell-culture experiments. Interference of autoantibody–autoantigen binding might be one way to reduce gluten-induced harm in patients with coeliac disease.2 Previous work from the group of Professor Sollid led to a panel of human monoclonal antibodies being generated by expression cloning of immunoglobulin genes from single plasma cells isolated from biopsy samples of the small bowel from patients with coeliac disease. This group have now further characterized these monoclonal antibodies.3,8 The antibodies are highly spe- cific for TG2 and bind preferentially to an Key advances ■■ Gradual introduction of gluten-containing food in infants during ongoing breastfeeding might modify the intestinal immune system and reduce the risk of developing coeliac disease in genetically susceptible individuals4 ■■ Gluten-triggered coeliac-disease-specific autoantibodies might have biological functions; the presence of TG2-positive autoantibodies during pregnancy might be associated with delayed fetal growth and reduced placental weight independent of maternal nutritional status6 ■■ The characterization of the binding of TG2 by coeliac disease autoantibodies has given insights into the mechanisms controlling the formation of TG2 autoantibodies in coeliac disease8 ■■ Small-bowel mucosal healing after introduction of a gluten-free diet should be the goal of treatment for coeliac disease9 ‘‘...coeliac disease often goes undiagnosed...earlier diagnosis by screening programmes is advocated ’’ © 2014 Macmillan Publishers Limited. All rights reserved
  • 46. S40 www.nature.com/nrgastro/collections/xxxx40  |  JANUARY 2014 www.nature.com/reviews GASTROENTEROLOGY & HEPATOLOGY open, Ca2+ -activated enzyme conformation. These findings agree with previous data on the coeliac disease epitope, but they also identify distinct additional conformational epitopes that cluster in the N‑terminal region of the enzyme. Two of these epitopes overlap with the fibronectin binding site in TG2. Interestingly, none of the epitopes are acces- sible when TG2 is in a cell-surface-bound form and, in coeliac disease, auto­antibodies might be generated against soluble, catalyti- cally active enzyme.8 Moreover, competition with fibronectin might lead to antibody- induced displacement of TG2 from the fibronectin network in the extracellular matrix and enzymatic activity of displaced TG2 might be increased as the enzyme mixes with tissue fluids in the gut. This increased enzyme activity could lead to more gluten deamidation and enhanced T‑cell activa- tion.8 It could also further explain previous in vitro findings of the biological functions of gluten‑triggered patient autoantibodies.2,7 In patients with coeliac disease, the elimi- nation of gluten from the diet normalizes TG2autoantibodylevels,alleviatessymptoms andimprovesthesmallbowelmucosalvillous architecture. However, previous studies have shown that mucosal healing (as determined fromfollow-upbiopsysamples)isincomplete in a substantial proportion of patients. Little information is available regarding the clini- cal significance of persistent villous atrophy despite adherence to a gluten-free diet, and there is uncertainty whether taking follow-up biopsy samples to confirm mucosal healing should be routine in all patients. Professor Ludvigsson’s group studied a large cohort of 7,625 patients with coeliac disease who had a follow-up biopsy 0.5–5.0 years (median 1.3 years) after initial diagnosis.9 Persistent villous atrophy was found in 43% of patients and the overall risk of lymphoprolifera- tive malignancy was higher in cases with incomplete recovery than in those who had achieved mucosal healing. In this registry- based study, details of dietary adherence were unavailable, and it was not possible to evalu- ate whether the lack of mucosal healing was caused by ongoing gluten exposure.9 As a gluten-free diet is restrictive in nature and gluten-free products are often not widely available, not very palatable and are costly, diet compliance remains inadequate. Advertent and inadvertent dietary lapses are the most common causes of persistent villous atrophy. The study by Ludvigsson and colleagues emphasizes the need for achieving mucosal healing when treating coeliac disease to reduce the risk of malignant complications.9 The systematic follow-up with intestinal biopsy samples seems to be helpful in identifying patients at risk. Health- care professionals should make an effort to help and encourage patients to maintain a strict gluten-free diet. Owing to the prob- lems with gluten-free diets, alternative or adjunctive therapies to treat coeliac disease are warranted.10 Coeliac disease is an interesting example of an autoimmune condition in which an environmental insult (gluten ingestion) is responsible for the self-maintenance of the autoimmune disease.1 Data published in 2013 have widened our understanding of the diversity of the condition and the complex interplay between genetic, immunological and environmental factors. School of Medicine, University of Tampere, Laakarikatu 1 (K. Kaukinen), Biokatu 10 (M. Mäki), FIN‑33520 Tampere, Finland. Correspondence to: M. Mäki markku.maki@uta.fi Competing interests M. Mäki declares associations with the following companies and patient organizations: Alvine Pharmaceuticals, BioLineRx, Finn Medi, Finnish Celiac Society, Flamentera, ImmusanT and Maki HealthTech. See article online for full details of the relationships. K. Kaukinen declares no competing interests. 1. Mäki, M. Coeliac disease and autoimmunity due to unmasking of cryptic epitopes? Lancet 348, 1046–1047 (1996). 2. Simon-Vescei, Z. et al. A single conformational transglutaminase 2 epitope contributed by three domains is critical for celiac antibody binding and effects. Proc. Natl Acad. Sci. USA 109, 431–436 (2012). 3. Di Niro, R. et al. High abundance of plasma cells secreting transglutaminase 2‑specific IgA autoantibodies with limited somatic hypermutation in celiac disease intestinal lesion. Nat. Med. 18, 441–445 (2012). 4. Ivarsson, A. et al. Prevalence of childhood celiac disease and changes in infant feeding. Pediatrics 131, e687–e694 (2013). 5. Sjöberg, V. et al. Intestinal T‑cell responses in celiac disease—impact of celiac disease associated bacteria. PLoS ONE 8, e53414 (2013). 6. Kiefte-de Jong, J. C. et al. Levels of autoantibodies against tissue transglutaminase during pregnancy are associated with reduced fetal weight and birth weight. Gastroenterology 144, 726–735 (2013). 7. Kalliokoski, S. et al. Celiac disease —specific TG2-targeted autoantibodies inhibit angiogenesis ex vivo and in vivo in mice by interfering with endothelial cell dynamics. PLoS ONE 8, e65887 (2013). 8. Iversen, R. et al. Transglutaminase 2‑specific autoantibodies in celiac disease target clustered, N‑terminal epitopes not displayed on the surface of cells. J. Immunol. 190, 5981–5991 (2013). 9. Lebwohl, B. et al. Mucosal healing and risk for lymphoproliferative malignancy in celiac disease. A population based cohort study. Ann. Intern. Med. 159, 169–175 (2013). 10. Kaukinen, K. et al. Advances in the treatment of coeliac disease: an immunopathogenetic perspective. Nat. Rev. Gastroenterol. Hepatol. http://dx.doi.org/10.1038/nrgastro.2013.141. BARRETT OESOPHAGUS IN 2013 Risk stratification and surveillance in Barrett oesophagus Emmanuel C. Gorospe and Kenneth K. Wang Advances are being made in understanding the pathogenesis, treatment outcomes and surveillance of Barrett oesophagus. Central obesity and age at onset of gastro-oesophageal reflux are being recognized as risk factors that have implications for screening. The persistent finding of nondysplastic Barrett oesophagus during surveillance is associated with low risk of malignant progression, whereas dysplastic Barrett oesophagus requires continued surveillance. Gorospe, E. C. & Wang, K. K. Nat. Rev. Gastroenterol. Hepatol. 11, 82–84 (2014); published online 10 December 2013; doi:10.1038/nrgastro.2013.237 In 2013, several studies continued to con- tribute to our evolving understanding of the pathogenesis, treatment outcomes, and yield of surveillance for Barrett oesophagus. These research endeavours have been pro- pelled by the current understanding that Barrett oesophagus is the strongest risk factor in the development of oesophageal adenocarcinoma (EAC). EAC has been the fastest rising malignancy in Western coun- tries over the past four decades.1 In spite of the fact that GERD and Barrett oesopha- gus are established risk factors for EAC, approximately half of patients with EAC do not present with chronic GERD or a prior diagnosis of Barrett oesophagus. © 2014 Macmillan Publishers Limited. All rights reserved
  • 47. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SBKEY ADVANCES IN MEDICINE JANUARY 2014  |  41 GASTROENTEROLOGY & HEPATOLOGY Given the ongoing interest in linking central obesity with the risk of EAC, Robertson et al.2 compared the length of cardiac mucosa, gastric acid exposure in the lower oesophageal sphincter (LES) and LES pressure between healthy volunteers with small waist circumference and volunteers with large waist circumference, matched by age and gender. Small waist circum­ ference was defined as <94 cm in males and <80 cm in females. The length of the cardiac mucosa was reliably evaluated using jumbo forceps biopsies across the squamocolumnar junction. Intrasphincteric acid reflux and pressure were assessed using standard pH and manometric studies. The study dem- onstrated an association between central obesity and increased cardiac mucosa length (2.5 mm versus 1.7 mm in volunteers with large and small waist circumference, respec- tively; P = 0.008) and more proximal gastric acid exposure in the LES (2.6 cm versus 4.1 cm, respectively; P = 0.027). Robertson et al.2 make an important con- tribution to our understanding of squamo- columnar junction injury in the setting of central obesity. On the basis of their find- ings, obesity and increased intra-abdomin­al pressure might contribute to increased acid reflux within the LES, leading to the proximal extension of the cardiac mucosa. This development might be similar to the progression of columnar-like epithelium found in EAC.3 This process might also represent an underlying mechanism for the rise of EAC and other gastro-oesophageal junctional malignancies in parallel with the increasing prevalence of obesity. Future studies are needed to elucidate the mecha- nistic pathways behind these changes in the gastro-oesophageal junction in patients with central obesity. Understanding these factors could lead to strategies for effec- tive screening of high-risk patients for EAC rather than relying on the presence of symptomatic GERD or a prior diagnosis of Barrett oesophagus. Thrift et al.4 presented a cross-sectional analysis of 683 patients who underwent upper gastrointestinal endoscopy to assess the significance of age at the onset of reflux symptoms. 236 patients with ­histologically- confirmed Barrett oesophagus and 447 patients without Barrett oesophagus were included in the study. All study participants completed a validated survey on reflux. Cumulative reflux duration in years was defined as the number of years in which the patient had frequent reflux symptoms, beginning at 10 years of age. Frequent reflux was defined as having weekly symptoms at a minimum. The age of onset was divided between ages 10–19, 20–29, 30–49, and 50–70 years. Their results show that patients whose onset of frequent reflux started when they were <30 years old were at higher risk of developing Barrett oesophagus (OR 15.1, 95% CI 7.9–28.8). This association was independent of the duration of cumulative reflux symptoms. Among patients with early onset reflux, those who reported a history of being treated with PPIs were at even higher risk of developing Barrett oesophagus than those who had not been treated with PPIs. These conclusions will require supporting evidence from other studies before they can be accepted as established risk factors.5 In addition, the underlying mechanism for the apparent risk of Barrett oesophagus associated with a younger age of onset is still unclear. These factors could include complicated life-course events—such as development of obesity and exposure to tobacco and alcohol—whose actual risk contributions might be difficult to individu- ally evaluate. For now, this cross-sectional study provides another layer of risk strati- fication in identifying patients who need to be screened for Barrett oesophagus in addition to our current approach of identi- fying patients with s­ymptomatic reflux and metabolic syndrome. Gaddam et al.6 conducted a multi­centre, retrospective cohort analysis of 1,401 patients with nondysplastic Barrett oesopha- gus who underwent endoscopic surveillance to assess risk stratification in surveillance endoscopy. Study participants were strati- fied according to the number of surveillance biopsies that did not detect dysplasia or EAC. After adjusting for age, gender and length of the Barrett mucosa, the persistence of non- dysplastic Barrett oesophagus was associated with low risk of progression to EAC. There was a progressive decline in the incidence of EAC between each surveillance endos- copy of 0.32%, 0.27%, 0.16%, 0.20%, and 0.11% from the annual risk of EAC. This study provides a new understanding of the clinical implication of multiple negative sur- veillance biopsies. These results might also support the need to re-evaluate our current surveillance guidelines, which are mostly arbitrary and have not been subjected to rigorous prospective trials.7 The results are important given population-based estimates of the absolute annual risk of EAC in Barrett oesophagus to be about 0.12%.8 Although the conclusions of Gaddam et al.6 are derived from retrospective data, varied surveillance intervals and lack of central pathology inter- pretation, their findings contribute to the growing evidence that there might be an end point for surveillance in patients with persistent nondysplastic Barrett oesophagus. The topic of surveillance remains an important issue when dealing with patients who have undergone radiofrequency ablation for Barrett-associated dysplasia. Gupta et al.9 performed a retrospective analysis of 592 patients from one of the largest US multicentre Barrett oesophagus treatment and surveillance programs. The goal was to estimate the incidence and risk factors for recurrence after inducing remis- sion of intestinal metaplasia using radio­ frequency ablation. In their study, complete remission from intestinal metaplasia had stringent criteria that included lack of visible or histologic evidence of intestinal meta­ plasia on two consecutive biopsies using the Key advances ■■ Central obesity was associated with increased gastric acid exposure in the lower oesophageal sphincter and expansion of the cardiac mucosa, which might lead to asymptomatic injury to the squamocolumnar junction2 ■■ Younger age at onset of frequent gastro-oesophageal reflux was associated with risk of Barrett oesophagus development, independent of the cumulative duration of reflux symptoms4 ■■ In a multicentre retrospective analysis, the persistent finding of nondysplastic Barrett oesophagus in surveillance biopsies was associated with decreased risk of malignant progression6 ■■ Patients treated for dysplastic Barrett oesophagus with radiofrequency ablation required continued surveillance owing to substantial risk of recurrence within 2 years of achieving remission from intestinal metaplasia9 ■■ Current endoscopic surveillance strategies performed in a community-based setting did not demonstrate decreased mortality from oesophageal adenocarcinoma; novel approaches and effective modalities are still needed to improve outcomes in Barrett oesophagus surveillance10 ‘‘For surveillance in Barrett oesophagus to be effective,we must find innovative ways to identify patients… ’’ © 2014 Macmillan Publishers Limited. All rights reserved
  • 48. S42 www.nature.com/nrgastro/collections/xxxx42  |  JANUARY 2014 www.nature.com/reviews GASTROENTEROLOGY & HEPATOLOGY Seattle protocol (which required obtaining four quadrant biopsy samples every 1–2 cm along the length of the Barrett oesophagus segment). In 24 months, 56% of patients achieved complete remission of intestinal metaplasia. However, 20% developed recur- rent metaplasia within 12 months and 33% had evidence of metaplasia after 24 months. Increased length of Barrett oesophagus segment and older age were associated with longer treatment time interval before achieving complete remission of intestinal metaplasia. However, no clinical or other endoscopic factors were found to be associ- ated with recurrence. Unlike patients with nondysplastic Barrett oesophagus, patients with Barrett-associated dysplasia seem to have a low but persistent risk of develop- ing recurrence even after treatment. Future studies are needed to find better predictors for assessing the risks of recurrence after endoscopic treatment. Improved ways of performing surveillance aside from our current endoscopic examination and biopsy protocol are also needed. The current surveillance strategy using upper endoscopy with biopsies was exam- ined in a case–control study by Corley et al.10 They compared the odds of having under- gone endoscopic surveillance in patients diagnosed with Barrett oesophagus who died of EAC with those for matched controls who had Barrett oesophagus but had not died of EAC. Patients with Barrett oesophagus who died of EAC were likely to have undergone a similar frequency of endoscopic surveil- lance to the controls (55.3% versus 60.4% of patients had endoscopic surveillance, respectively). Their conclusion showed no association between surveillance and decline in EAC-related deaths (OR 0.99, 95% CI 0.36–2.75) in spite of adjusting for multi- ple confounders. This study compels us to again re-examine our current endoscopic su­rveillancestrategiesforBarrettoesophagus. For surveillance in Barrett oesophagus to be effective, we must find innovative ways to identify patients who would greatly benefit fromit.Otherwise,surveillancewillbeafutile exerciseforthosewhomightnotbenefitfrom it or it might be poorly utilized for those patients who need it the most. Novel endo- scopic technologies, predictive biomarkers, and innovative sampling techniques—such as transnasal endoscopy and cytosponge— might provide the answers to this ongoing dilemma. In the coming years, we can expect more studies attempting to refine the current methods for risk ­stratification and s­urveillance in Barrett oesophagus. Barrett’s Esophagus Unit, Division of Gastroenterology & Hepatology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA (E. C. Gorospe, K. K. Wang) Correspondence to: K. K.Wang wang.kenneth@mayo.edu Competing interests E. C. Gorospe declares associations with the following company: Boston Scientific. K. K. Wang declares associations with the following companies: CDX Diagnostics; Covidien; CSA Medical; Fujinon; Ninepoint Medical. See the article online for full details of the relationships. 1. Pohl, H., Sirovich, B. & Welch, H. G. Esophageal adenocarcinoma incidence: are we reaching the peak? Cancer Epidemiol. Biomarkers Prev. 19, 1468–1470 (2010). 2. Robertson, E. V. et al. Central obesity in asymptomatic volunteers is associated with increased intrasphincteric acid reflux and lengthening of the cardiac mucosa. Gastroenterology 145, 730–739 (2013). 3. Quante, M., Abrams, J. A. & Wang, T. C. The rapid rise in gastroesophageal junction tumors: is inflammation of the gastric cardia the underwater iceberg? Gastroenterology 145, 708–711 (2013). 4. Thrift, A. P., Kramer, J. R., Qureshi, Z., Richardson, P. A. & El-Serag, H. B. Age at onset of GERD symptoms predicts risk of Barrett’s esophagus. Am. J. Gastroenterol. 108, 915–922 (2013). 5. Cook, M. B. Optimization and expansion of predictive models for Barrett’s esophagus and esophageal adenocarcinoma: could a life- course exposure history be beneficial? Am. J. Gastroenterol. 108, 923–925 (2013). 6. Gaddam, S. et al. Persistence of nondysplastic Barrett’s esophagus identifies patients at lower risk for esophageal adenocarcinoma: results from a large multicenter cohort. Gastroenterology 145, 548–553 (2013). 7. Shaheen, N. J. & Hur, C. Garlic, silver bullets, and surveillance upper endoscopy for Barrett’s esophagus. Gastroenterology 145, 273–276 (2013). 8. Hvid-Jensen, F., Pedersen, L., Drewes, A. M., Sorensen, H. T. & Funch-Jensen, P. Incidence of adenocarcinoma among patients with Barrett’s esophagus. N. Engl. J. Med. 365, 1375–1383 (2011). 9. Gupta, M. et al. Recurrence of esophageal intestinal metaplasia after endoscopic mucosal resection and radiofrequency ablation of Barrett’s esophagus: results from a US Multicenter Consortium. Gastroenterology 145, 79–86 (2013). 10. Corley, D. A. et al. Impact of endoscopic surveillance on mortality from Barrett’s esophagus-associated esophageal adenocarcinomas. Gastroenterology 145, 312–319 (2013). IBD IN 2013 Enriching the therapeutic armamentarium for IBD Silvio Danese and Laurent Peyrin-Biroulet In 2013, several new IBD drugs, including golimumab and vedolizumab, have been approved or completed successful programmes, showing efficacy in both Crohn’s disease and ulcerative colitis. In addition, classic IBD drugs have been formulated for colonic delivery, such as budesonide MMX®, which was recently approved for mild-to-moderate ulcerative colitis. Danese, S. & Peyrin-Biroulet, L. Nat. Rev. Gastroenterol. Hepatol. 11, 84–86 (2014); published online 24 December 2013; doi:10.1038/nrgastro.2013.246 The advent of anti-TNF agents dramati- cally changed the way we treat IBD that is refractory to standard medications (cortico­steroids, thiopurines or metho- trexate), by achieving steroid-free remis- sion, improving quality of life and reducing hospitalizations and surgeries. However, primary non­response, intolerance and loss of response are frequent for all avail- able anti-TNF agents.1,2 In the context of more ambitious therapeutic goals, such as mucosal healing, deep remission and histo­ logical healing, and evolving therapeutic strategies based on tight monitor­ing and rapid step-up approaches, new biologic agents are eagerly awaited. Building on the publication of studies on the biologic agents ustekinumab and tofacitinib in 2012, 2013 will stand out as a year of great success for the in­troduction of new drugs for the t­reatment of IBD. TNF remains a key target in the treat- ment of IBD and the new anti-TNF agent golimumab has been shown to be very effective in patients who have moderately to severely active ulcerative colitis.3,4 In the SC induction study (PURSUIT-SC), patients with ulcerative colitis unrespon- sive to conventional treatment were ran- domly assigned to receive placebo or golimumab at two different doses given 2 weeks apart (400 mg followed by 200 mg, or 200 mg followed by 100 mg). At week 6, significantly more g­olimumab-treated © 2014 Macmillan Publishers Limited. All rights reserved
  • 49. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SBKEY ADVANCES IN MEDICINE JANUARY 2014  |  43 GASTROENTEROLOGY & HEPATOLOGY patients achieved response, remission and mucosal healing.3 In the subsequent main- tenance study (PURSUIT‑M), patients who responded to golimumab induction therapy were randomly assigned to receive golimumab (50 mg or 100 mg) or placebo every 4 weeks for 52 weeks. At week 54, patients treated with golimumab achieved significant continuous response, remission and mucosal healing compared with those who received placebo.4 Together, these studies bring a new treatment option to patients with ulcerative colitis, one that is effective, convenient and has a good safety profile. Golimumab has been approved by both the FDA and the European Medicines Agency (EMA), bringing the number of anti-TNF agents available for the treatment of ulcerative colitis to three (infliximab, ad­alimumab and golimumab). Among new biologic agents in the pipe- line for the treatment of IBD,5 several classes of compound seem promising. Vedolizumab is a humanized mono­ clonal antibody that specifically antago- nizes α4 β7 integrin, by inhibiting its binding to intestinal mucosal addressin cell adhesion molecule 1 (MAdCAM‑1). MAdCAM‑1 is preferentially expressed on blood vessels and lymph nodes of the gastrointestinal tract. The α4 β7 integrin is expressed on a subset of circulating white blood cells that have been shown to have a key pathogenic role in IBD. The binding specificity and selective antagonism of vedolizumab might ultimately confer an improved risk-to-benefi­t profile for patients with IBD. Indeed, the gut selec- tivity of vedolizumab is less likely to pre­ dispose patients to systemic adverse events outside the gastrointestinal tract, such as infection and/or neoplasia, than other biologic agents.6 Announced in early 2009, the GEMINI studies comprise a phase III programme evaluating the effect of vedolizumab on clinical response and remission along with the effect on mucosal healing in patients with ulcerative colitis, and long-term safety in patients with moderately to severely active Crohn’s disease or ulcerative colitis for whom treatment with at least one con- ventional therapy or a TNF antagonist had failed. The GEMINI programme con- sists of four separate studies: a placebo- controlle­d induction and maintenance study in patients with ulcerative colitis (GEMINI I); a placebo-controlled­induc- tion and maintenance study in patients with Crohn’s disease (GEMINI II); a placebo- controlled induction study in patients with Crohn’s disease with prior TNF antagonist failure (GEMINI III); and two open-label long-term safety studies in patients with either Crohn’s disease or ulcerative colitis (GEMINI LTS). The findings from GEMINI I demon- strated that intravenous vedolizumab at a dose of 300 mg is highly effective at induc- ing and maintaining clinical remission and mucosal healing in patients with ulcerative colitis.7 Vedolizumab was also effective as induction therapy in patients with Crohn’s disease when considering clinical remission at week 6, but the difference between the active and placebo arms did not reach stat­ istical significance when considering clini- cal response defined as a 100 point decrease of the Crohn’s disease activity index.8 The placebo effect (absence of evaluation of objective signs of inflammation, such as mucosal healing) and/or the fact that the studied population had Crohn’s disease of long duration and previous exposure to anti-TNF therapy is a possible explan­ation for these results. Importantly, patients with Crohn’s disease who had a response to induction therapy who continued to receive vedolizumab (rather than switch- ing to placebo) were successfully brought into remission at week 52. Vedolizumab was well tolerated in patients with either ulcera­ tive colitis or Crohn’s disease. Approval of vedolizumab by the FDA and the EMA for both Crohn’s disease and ulcerative colitis is pending. Beside the novel biologic agents that are mainly developed for patients with moderate or severe disease, new drugs are also being investigated for the treatment of those with mild or moderate disease, trying to optimize old compounds with new colonic delivery systems. This scen­ ario is relevant for a novel oral formula- tion of budesonide that uses Multi-Matrix System (MMX®, Cosmo Pharmaceuticals, Milan) technology to extend release to the colon. In a recent controlled trial, bude- sonide MMX®(9 mg once daily) was safe and more effective than placebo at induc- ing remission in patients with active, mild- to-moderate ulcerative colitis.9 Safety was comparable to that of placebo, supporting the lack of adverse effects recognized with systemic steroids. Budesonide MMX®has been approved by the FDA and in some European countries for the treatment of mild or moderate u­lcerative colitis. In conclusion, the approval of new drugs, including biologic agents, will dramatically change our practice after 15 years using anti-TNF therapy. However, the launch of these new biologic agents raises several questions. First, which biologic should be used as first-line therapy in patients who have refractory IBD? Second, when and how should biologic agents be switched? Only head-to-head trials can address which bio- logic agent to use first, because an indirect comparison across trials is not sufficient to guide decision-making. As no head-to-head trials have been conducted so far, the cost of treatment, convenience and satisfaction for the patient, route of administration, and the safety and efficacy profile should all be considered when making c­linical decisions. When contemplating the issue of switch- ing biologic agents, some lessons can be learned from the treatment of rheumatoid arthritis, for which nine biologic agents have been approved. TNF inhibitors were the first biologic therapies approved for use in rheumatoid arthritis, followed by the T‑cell co-stimulation inhibitor a­batacept, the B‑cell-depleting monoclonal anti- body rituximab, the IL‑1 receptor blocker a­nakinra and the IL‑6 receptor inhibitor tocilizumab. Before the advent of biologic agents that do not inhibit TNF, switching from one TNF inhibitor to another was common practice for patients with rheuma- toid arthritis whose disease was not respon- sive to a particular treatment; however, if Key advances ■■ A substantial proportion of patients with IBD are unresponsive and intolerant to anti-TNF agents, and novel drugs are needed to fill the unmet medical need ■■ After many years of translational research, in 2013 several new agents have been shown to be effective for IBD3,4,6–8 ■■ Vedolizumab is a novel non-TNF inhibitor effective for the treatment of IBD6–8 ■■ Budesonide MMX®is not a biological agent, but a conventional steroid with a colonic delivery formulation that provides efficacy with a good safety profile9 ‘‘…the gut selectivity of vedolizumab is less likely to predispose patients to systemic adverse events… ’’ ‘‘…when and how should biologic agents be switched? ’’ © 2014 Macmillan Publishers Limited. All rights reserved
  • 50. S44 www.nature.com/nrgastro/collections/xxxx44  |  JANUARY 2014 www.nature.com/reviews GASTROENTEROLOGY & HEPATOLOGY more than one TNF inhibitor provides in­adequate responses and/or similar toler- ability issues, switching to a different class of agent might provide a more effective option and is now recommended. Overall, the findings of the studies pub- lished in 2013, as well as those of others published in recent years, offer hope that patients with IBD will benefit from the launch of new drugs by changing the course of their disease together with their daily life. IBD Centre, Division of Gastroenterology, Humanitas Clinical and Research Centre, Via Manzoni 56, 20089 Rozzano, Milan, Italy (S. Danese). INSERM U954 and Department of Gastroenterology, Université de Lorraine, Vandoeuvre‑lès‑Nancy, France (L. Peyrin‑Biroulet). Correspondence to: S. Danese sdanese@hotmail.com Competing interests S. Danese declares associations with the following companies: Abbott Laboratories, Abbvie, Actelion, Alphawasserman, Astra Zeneca, Cellerix, Celltrion, Cosmo Pharmaceuticals, Merck & Co, Ferring, Genentech, Grunenthal, Johnson & Johnson, Millenium Takeda, Novo Nordisk, Nycomed, Pfizer, Pharmacosmos, Schering-Plough, Tigenix, UCB Pharma and Vifor. L. Peyrin-Biroulet declares associations with the following companies: Abbott, BMS, Boehringer-Ingelheim, Celltrion, Ferring, Genentech, HAC-pharma, Hospira, Janssen, Merck, Mitsubishi, Norgine, Pharmacosmos, Pilège, Shire, Takeda, Therakos, Tillots, UCB Pharma and Vifor. See the article online for full details of the relationships. 1. Nielsen, O. H. & Ainsworth, M. A. Tumor necrosis factor inhibitors for inflammatory bowel disease. N. Engl. J. Med. 369, 754–762 (2013). 2. D’Haens, G. R. et al. The London Position Statement of the World Congress of Gastroenterology on Biological Therapy for IBD with the European Crohn’s and Colitis Organization: when to start, when to stop, which drug to choose, and how to predict response? Am. J. Gastroenterol. 106, 199–212 (2011). 3. Sandborn, W. J. et al. Subcutaneous golimumab induces clinical response and remission in patients with moderate‑to‑severe ulcerative colitis. Gastroenterology http://dx.doi.org/ 10.1053/j.gastro.2013.05.048. 4. Sandborn, W. J. et al. Subcutaneous golimumab maintains clinical response in patients with moderate‑to‑severe ulcerative colitis. Gastroenterology http://dx.doi.org/10.1053/ j.gastro.2013.06.010. 5. Danese, S. New therapies for inflammatory bowel disease: from the bench to the bedside. Gut 61, 918–932 (2012). 6. Cominelli, F. Inhibition of leukocyte trafficking in inflammatory bowel disease. N. Engl. J. Med. 369, 775–776 (2013). 7. Feagan, B. G. et al. Vedolizumab as induction and maintenance therapy for ulcerative colitis. N. Engl. J. Med. 369, 699–710 (2013). 8. Sandborn, W. J. et al. Vedolizumab as induction and maintenance therapy for Crohn’s disease. N. Engl. J. Med. 369, 711–721 (2013). 9. Travis, S. P. et al. Once-daily budesonide MMX in active, mild‑to‑moderate ulcerative colitis: results from the randomised CORE II study. Gut http://dx.doi.org/10.1136/ gutjnl‑2012‑304258. SMALL BOWEL ENDOSCOPY IN 2013 The reality and the potential Uday C. Ghoshal 2013 saw several advances in small bowel endoscopy: new 3D visualization software, increased battery life, side-viewing cameras and higher frame rate. Studies on prokinetics for patient preparation, safety in the elderly, rebleeding after negative capsule endoscopy and defining optimum training requirements for fellows were encouraging. Procedure time and small bowel length evaluated by double-balloon and spiral endoscopy were shown to be comparable. Ghoshal, U. C. Nat. Rev. Gastroenterol. Hepatol. 11, 86–87 (2014); published online 7 January 2014; doi:10.1038/nrgastro.2013.257 Until 2000, the small bowel was an area of the gastrointestinal tract that was beyond the reach of endoscopists. Hence, aetio- logical diagnosis in patients who had an obscure gastrointestinal bleed (which con- stitutes 5% of patients with a gastro­intestinal bleed),1 remained unexplored and resulted in substantial morbidity, mortality, health- care costs and unnecessary surgery. The development of capsule endoscopy in 2000 changed everything. 13 years on and 2013 has witnessed several key advances in endo­ scopy of the small bowel. Currently, small bowel endoscopy consists not only of capsule endoscopy but also device-assisted endo­ scopy, such as single or double-balloon and spiral endoscopy. In one interesting development, 3D recon- struction software was developed and ini- tially tested in phantom simulators, which were prepared from readily available mate- rials such as cardboard boxes.2 The principle of this technology involved reconstruct- ing the shape of an object from 2D images based on data available on gradual variation of shading (shape-from-shading­). To repre- sent the different colours and shapes seen inside the gut, flat or protruding objects in red, yellow and white were used in the phantom models. Initial experiments showed that the accuracy of the 3D software was 90%, 70% and 45% for red, yellow and white phantom models, respectively. Subsequently, the potential of the 3D reconstruction soft- ware to enhance images obtained by capsule endoscopy in patients was evaluated by seven endoscopists.2 192 capsule endoscopy images were reviewed: 50 vascular, 73 inflammatory and 69 protruding lesions. Visualisation was more enhanced for vascular lesions than it was for inflammatory or protruding lesions (56% versus 23% versus <10%, respectively).2 Limitations of capsule endoscopy include inadequate examination of the small bowel along its length due to inadequate battery life and the inability to visualize some areas on the side wall because the camera is located at the end of the capsule. Recent work has seen the development of a capsule that has four cameras with side-viewing ability, resulting in 360° motion technology (the cameras only work when the capsule is in motion), and a long battery life of about 15 hours(CapsoCamSV1®;CapsoVisionInc., Saratoga, CA).3 In this study from Germany on 33 patients, the authors found that the landmark of duodenal papilla could be seen in 22 (71%) patients when using this new capsule endoscopy system compared with a median frequency of 18% (range 10–60%) when using conventional capsule technol- ogy.3 Small bowel transit was 258 ± 136 min (median 258 min, range 40–621 min), which is much shorter than the capsule battery life of15 hours.Theseauthorsalsoclaimanaddi- tional advantage as this new technology does not use radio-frequency transmission, hence, it is expected to be safe in patients who have a cardiac pacemaker.3 In a separate study, there has also been an attempt to localise lesions more accurately by introducing a capsule fitted with protruding wheels attached to a spring mechanism (odometer).4 The springs allow the wheels to expand and retract to fit the lumen during the capsule’s passage through the gut. Information about the loca- tion of the lesion in relation to the passage of the capsule through the pylorus can therefore be obtained. Moreover, these springs stabi- lize the video recording by reducing random n­on-forward movement of the capsule. Evaluating the whole length of the small intestine is important to avoid missing lesions during capsule endo­scopy. One method that makes this possible is increasing the capsule’s battery life; another is to increase small bowel transit by using pharmaceutical agents such as prokinetics. A meta-analysis published © 2014 Macmillan Publishers Limited. All rights reserved
  • 51. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SBKEY ADVANCES IN MEDICINE JANUARY 2014  |  45 GASTROENTEROLOGY & HEPATOLOGY in 2013 assessed the completeness of small bowel evaluation in studies published up to November 2012, in which capsule endoscopy performed following prokinetic administra- tion was compared with capsule endoscopy performed after no prokinetic administra- tion.5 In the 17 studies eligible for inclusion (14 prospective, 3 retro­spective), 876 patients had capsule endo­scopy with prokinetics and 1,028patientshadcapsuleendoscopywithout prokinetics. Although complete small bowel evaluationwasmoreoftenachievedwith pro- kinetics (odds ratio [OR] 1.96, 95% CI 1.38– 2.78), meto­clopramide was the prokinetic most frequently associated with complete small bowel evaluation as compared with controls (OR 2.8, 95% CI 1.35–3.21), but not erythro­mycin (OR 1.36, 95% CI 0.61–3.03).5 No prokinetic agent improved the diagnostic yield of capsule endoscopy.6 Like any other type of gastrointestinal endoscopy, capsule endoscopy requires adequate training to achieve optimum diag- nostic yield. However, until now the criteria for adequate training for capsule endoscopy have been based merely on expert opinion and societal guidelines and not on any sci- entific evidence. In a single-centre prospec- tive study, gastroenterology fellows were trained in capsule endoscopy using a struc- tured programme devised by the American Society of Gastrointestinal Endoscopy and subsequently evaluated using a newly devel- oped formalized assessment tool called the Capsule Competency Test (CapCT).6  The CapCT score obtained by staff capsule endoscopists was considered the gold stand- ard; achievement of a score that was 90% of that achieved by staff members was taken as optimal competence. Of 39 fellows involved in the study, the mean scores for trainees with <10, 11–20, and 21–35 capsule endoscopy interpret­ations were 79%, 79%, and 85%, respectively. Hence, the authors suggest that fellows need to perform at least 20 super- vised capsule endoscopies before they can be c­ertified as adequately trained.6 Owing to the safety and relatively less- invasive nature of capsule endoscopy, its use has become popular even in the elderly pop- ulation. However, data on the safety of this technology in the elderly have been lacking. Encouragingly, in a retrospective study from the Mayo Clinic, Florida, the frequency of adverse events in 195 patients >80 years of age was comparable with the frequency of adverse events in 585 i­ndividuals <80 years of age.7 In a study of 696 patients with obscure overt or occult gastrointestinal bleeding, the rebleeding rate was lower among patients who had negative capsule endoscopy find- ings (34/207; 16%) than in those who had positive capsule endoscopy findings (220/489; 45%) during a median follow-up period of 24 months (range 12–36 months).8 This finding confirms similar observations made in studies with smaller numbers of patients and suggests that further invasive investigation could be deferred if the ­findings of capsule endoscopy are negative. The limitations of capsule endoscopy include the inability to steer the capsule inside the gut lumen and to take biopsy samples from any lesions that are visualized, and the lack of therapeutic capability. Device- assisted endoscopy, such as double-balloon and single-balloon endoscopy, has these capabilities. However, balloon endo­scopy is associated with a longer procedure time and the failure to evaluate the whole length of the small bowel in a proportion of patients. Spiral endoscopy is a novel technology that is believedtoovercomesomeofthesedisadvan- tages. In a multi­centre study (conducted at fivecentres),aftercapsuleendoscopy,patients underwent double-balloon endoscopy (n = 191) or spiral endoscopy (n = 50). 80% of patients included in the study had obscure gastrointestinal bleeding. Double-balloon and spiral endoscopy had an overall diag- nosticyieldof75%and70%,respectively.The procedure time (60 min, range 45–80 min versus 55 min, range 45–80 min; P = ns) and the length of small bowel evaluated (200 cm, range 150–300 cm versus 220 cm, range 200–300 cm; P = ns) were comparable for double-balloon and spiral endoscopy, respec- tively.9 These findings, therefore, suggest that the popular belief that spiral endoscopy examines a longer length of small bowel in a shorter time might not be correct.9 Despite these advances in small bowel endoscopy, a lot of work still needs to be done. Although capsule endoscopy is non- invasive, pop­ular and examines a longer length of the small bowel, it lacks thera­peutic capabilities. By contrast, device-assisted endoscopy has therapeutic capabilities, but often results in incom­plete examination. Furthertechnologica­ladvancesare,therefore, much needed. Department of Gastroenterology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Raebareli Road, Lucknow 226014, India. udayghoshal@gmail.com Competing interests The author declares no competing interests. 1. Lewis, B. & Goldfarb, N. Review article: The advent of capsule endoscopy—a not-so- futuristic approach to obscure gastrointestinal bleeding. Aliment. Pharmacol.Ther. 17, 1085–1096 (2003). 2. Koulaouzidis, A. et al. Three-dimensional representation software as image enhancement tool in small-bowel capsule endoscopy: a feasibility study. Dig. Liver Dis. 45, 909–914 (2013). 3. Friedrich, K., Gehrke, S., Stremmel, W. & Sieg, A. First clinical trial of a newly developed capsule endoscope with panoramic side view for small bowel: a pilot study. J. Gastroenterol. Hepatol. 28, 1496–1501 (2013). 4. Karargyris, A. A. & Koulaouzidis, A. Capsule- odometer: a concept to improve accurate lesion localisation. World J. Gastroenterol. 19, 5943–5946 (2013). 5. Koulaouzidis, A., Giannakou, A., Yung, D. E., Dabos, K. J. & Plevris, J. N. Do prokinetics influence the completion rate in small-bowel capsule endoscopy? A systematic review and meta-analysis. Curr. Med. Res. Opin. 29, 1171–1185 (2013). 6. Rajan, E. et al. Training in small-bowel capsule endoscopy: assessing and defining competency. Gastrointest. Endosc. 78, 617–622 (2013). 7. Gomez, V. et al. Safety of capsule endoscopy in the octogenarian as compared with younger patients. Gastrointest. Endosc. 78, 744–749 (2013). 8. Riccioni, M. E. et al. Negative capsule endoscopy in patients with obscure gastrointestinal bleeding reliable: recurrence of bleeding on long-term follow-up. World J. Gastroenterol. 19, 4520–4525 (2013). 9. Rahmi, G. et al. Multicenter comparison of double-balloon enteroscopy and spiral enteroscopy. J. Gastroenterol. Hepatol. 28, 992–998 (2013). Key advances ■■ The feasibility of novel 3D reconstruction software for enhancing capsule endoscopy imaging has been demonstrated2 ■■ A capsule endoscope with four cameras, side-viewing capability, a higher frame rate and longer battery life has been developed, which could evaluate a longer length of small bowel and its side wall3 ■■ A meta-analysis showed that prokinetic drugs, such as metoclopramide, increase complete small bowel evaluation by capsule endoscopy5 ■■ Optimum capsule endoscopy training for fellows was defined as a minimum of 20 supervised capsule endoscopies6 ■■ Capsule endoscopy is safe in patients >80 years old, negative capsule endoscopy is associated with a lesser rate of rebleeding, and procedure time and the length of small bowel evaluated by double-balloon and spiral endoscopy is comparable7–9 ‘‘Despite these advances in small bowel endoscopy, a lot of work still needs to be done ’’ © 2014 Macmillan Publishers Limited. All rights reserved
  • 52. Editors’ picks of the year Diagnosis of hepatitis E Rakesh Aggarwal Hepatitis E is common in developing countries, and occasional cases of this disease have been identified in developed countries. The currently available diagnostic tests have undergone limited testing and often yield discordant results. In this article, Rakesh Aggarwal reviews the information on diagnosis of hepatitis E, including past and current diagnostic tests. doi:10.1038/nrgastro.2012.187 Medical therapies for hepatocellular carcinoma: a critical view of the evidence Augusto Villanueva, Virginia Hernandez-Gea and Josep M. Llovet As the burden of hepatocellular carcinoma continues to increase, attention turns to the appropriate management of the disease. In this Review, Josep Llovet and co-authors discuss and critique the currently available medical interventions for the treatment and management of hepatocellular carcinoma, as well as introduce future developments in the field. doi:10.1038/nrgastro.2012.199 Development and developmental disorders of the enteric nervous system Florian Obermayr, Ryo Hotta, Hideki Enomoto and Heather M. Young The enteric nervous system (ENS) arises from neural-crest-derived cells. Here, Heather Young and colleagues provide an overview of the progress made in the past 5 years in our understanding of ENS development and the potential involvement of defects in ENS development in paediatric motility disorders. doi:10.1038/nrgastro.2012.234 The digestive neuronal–glial–epithelial unit: a new actor in gut health and disease Michel Neunlist, Laurianne Van Landeghem, Maxime M. Mahé, Pascal Derkinderen, Stanislas Bruley des Varannes and Malvyne Rolli-Derkinderen The permeability of the intestinal epithelial barrier has a central role in the regulation of fluid and nutrient intake as well as in the control of the passage of pathogens. This Review by Michel Neunlist et al. summarizes current studies characterizing neuronal and glial effects on the intestinal epithelial barrier. The authors also outline the novel concept of a digestive neuronal–glial–epithelial unit. doi:10.1038/nrgastro.2012.221 Functional dyspepsia—symptoms, definitions and validity of the Rome III criteria Jan Tack and Nicholas J. Talley The Rome III consensus has divided functional dyspepsia into two subgroups; postprandial distress syndrome, characterized by postprandial fullness and early satiation, and epigastric pain syndrome, characterized by epigastric pain or burning. In this Review, Jan Tack and Nicholas Talley describe the symptoms of functional dyspepsia and discuss the evidence to support the existence of the two subgroups. doi:10.1038/nrgastro.2013.14 Future therapies for chronic hepatitis C Noura M. Dabbouseh and Donald M. Jensen Worldwide, ~170 million people are thought to be chronically infected with HCV. Patients with chronic hepatitis C can develop serious long- term complications. Therapy for hepatitis C has progressed rapidly in the past few years; here, Donald Jensen and Noura Dabbouseh discuss the latest advances. doi:10.1038/nrgastro.2013.17 Progression of NAFLD to diabetes mellitus, cardiovascular disease or cirrhosis Quentin M. Anstee, Giovanni Targher and Christopher P. Day NAFLD is becoming much more common, and will soon be the major underlying aetiology for liver transplantation. This article by Christopher Day and colleagues considers the evidence that NAFLD is a multisystem disease and outlines the factors that determine interindividual variation in the development and progression of NAFLD. doi:10.1038/nrgastro.2013.41 The gastrointestinal mucus system in health and disease Malin E. V. Johansson, Henrik Sjövall and Gunnar C. Hansson Gastrointestinal mucus is the first line of defence against bacteria; the organization of this protective system varies markedly along the digestive tract. In this Review, Gunnar Hansson and co-authors provide an overview of the mucus system and discuss the role of mucus in health and disease. doi:10.1038/nrgastro.2013.35 Mechanisms underlying weight loss after bariatric surgery Alexander D. Miras and Carel W. le Roux Bariatric surgery is an effective treatment for obesity, providing long-term maintenance of weight loss. Here, Alexander Miras and Carel le Roux discuss the various mechanisms by which the different types of bariatric surgery (including Roux-en-Y gastric bypass, vertical sleeve gastrectomy and adjusted gastric banding) exert their effects on body weight. Evidence from animal and human studies is discussed. doi:10.1038/nrgastro.2013.119 NAFLD, NASH and liver cancer Gregory A. Michelotti, Mariana V. Machado and Anna Mae Diehl The incidence of NAFLD, which increases the risk of liver cancer, is increasing to epidemic proportions. Anna Mae Diehl and colleagues outline the correlations between liver cancer and NAFLD-related cirrhosis, and the role of the metabolic syndrome in the development of liver cancer. Advances in understanding the progression of NAFLD to hepatocellular carcinoma from preclinical models are also discussed in this Review. doi:10.1038/nrgastro.2013.183 February 2014 volume 11 no. 2 www.nature.com/reviews YEAR IN REVIEW Key opinion leaders comment on advances made in 2013 Special focus issue on IBD through the ages Experts consider age-specific differences GASTROENTEROLOGY & HEPATOLOGY focus IBD through the ages nrgastro_OFC_FEB14.indd 1 22/01/2014 15:48 * * * * * * * * * * Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Gastroenterology & Hepatology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register A selection of articles published during 2013 in Nature Reviews Gastroenterology & Hepatology: © 2014 Macmillan Publishers Limited. All rights reserved
  • 53. NEPHROLOGY 46  |  JANUARY 2014 www.nature.com/reviews STEM CELLS IN 2013 Potential use of stem or progenitor cells for kidney regeneration Luigi Biancone and Giovanni Camussi 2013 saw the publication of numerous studies that identified resident renal stem or progenitor cells, induced pluripotent stem cells and strategies based on stem cell paracrine action, which all might be suitable for kidney regeneration after injury. Biancone, L. & Camussi, G. Nat. Rev. Nephrol. 10, 67–68 (2014); published online 3 December 2013; doi:10.1038/nrneph.2013.257 A new frontier of medicine is the regener­ ation of injured organs. Nephrologists dream of clinical strategies to repair dif­ ferent nephron compartments after acute and chronic injury. Preclinical studies have shown the beneficial effects of treat­ ment with stem cells of various origins. In the past decade, researchers have focused extensively on identifying resident stem or progenitor cells within the kidney to investi­gate their regenerative potential for use in stem cell-based therapies. Renal pro­ genitor cells have been identified in rodents and humans, but despite their ability to localize within the kidney after injury or during development, their role in regenera­ tion and their potential therapeutic appli­ cations are still elusive. However, most of these progenitor cells do not fulfil the cri­ teria that define true stem cells, such as self renewal, clonogenicity and multipotential differentiation capacity, but can instead be considered as pre­cursors of differentiated renal epithelial cells. Research carried out in 2013 has furthered our understanding of the resident stem cell ­contribution to renal regeneration. One key study identified a novel c‑Kit+ (mast/stem cell growth factor receptor Kit) cell population, localized to the thick ascending limb of the loop of Henle in neonatal rat kidneys, which displayed the characteristic properties of stem cells and generated both mesoderm and ectoderm progeny.1 Moreover, when administered in rats with acute ischaemia–reperfusion injury, in vitro expanded c‑Kit+ cells con­ tributed to kidney recovery, by exerting a para­crine action and engraftment within renal structures such as glomeruli, vessels and tubules (Figure 1). Whether a similar stem cell population is present in human kidneys remains to be determined, but if so, it would have important biological and therapeutic implications. Stem cells are responsible for nephrogenesis in humans up to the 34th week of gestation. However, a cell population with the same proper­ ties of putative fetal stem cells has not yet been detected in the adult kidney, despite the identification of renal progenitor cells expressing CD133, CD24 and nestin in ­different sites of the nephron.2,3 Another study identified a highly clono­genic and self-renewing epithelial nephron progenitor population from mid-­ gestational human fetal kidneys, which defined a source of cells with potential for use in the regeneration of nephron epi­ thelial structures (loop of Henle, proximal and distal tubules).4 After engraftment onto a chick embryo chorioallantoic membrane, these cells initi­ated tubulogenesis and showed nephron epithelial differentiation potential. In vivo engraftment of these cells showed beneficial effects and improved renal function in the 5/6 chronic progres­ sive mouse renal injury model that mimics human chronic kidney disease. Notably, the regener­ative potential of human nephron progenitor cells in the remnant kidney was detected at just 3 months after their injection. Identification of renal stem or progeni­ tor cells in fetal or adult kidneys is relevant to understanding the regenerative poten­ tial of the kidney, but is limited as a thera­ peutic approach because the cell source is not easily accessible and only a potential iPSCs or GPSCs Mesodermal development Tubular specification Engraftment AKI recoveryKidney regeneration Tubular epithelial cell repair hucMSC Exosomes Resident stem cells derived from neonatal or fetal kidney Human fetal kidney NCAM+ cells Ex-vivo expanded neonatal rat c-Kit+ cells Engraftment Differentiation Re-differentiation ProliferationDe-differentiation Activation of ERK1/2 Tubular cell injury Figure 1 | Strategies for kidney regeneration. Abbreviations: AKI, acute kidney injury; c‑Kit, mast/stem cell growth factor receptor Kit; ERK1, mitogen-activated protein kinase 3; ERK2, mitogen-activated protein kinase 1; GPSC, germline cell-derived pluripotent stem cell; hucMSC, human umbilical cord mesenchymal stem cell; iPSC, induced pluripotent stem cell; NCAM, neural cell adhesion molecule 1. © 2014 Macmillan Publishers Limited. All rights reserved
  • 54. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB NEPHROLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  47 allogeneic therapy can be envisaged. Alternative sources of stem or progenitor cells, which bypass these limitations must therefore be identified. One such strategy is to develop human induced pluripotent stem cells (hiPSCs) with nephrogenic potential. An important study in this area of research achieved an efficient induc­ tion of nephrogenic inter­mediate meso­ derm generated from hiPSCs.5 The researchers established a system of homo­ lo­gous recombi­nation in hiPSCs using bacter­ial artificial chromosome vectors and a genomic DNA analysis array based on detection of single-nucleotide polymorph­ isms. This system generated green fluores­ cent protein reporter cell lines in hiPSCs for protein odd-skipped-related 1, an early marker of intermediate mesoderm. These cells were used for monitoring differen­ tiation of the cell lines. By using combi­ national treatments with growth factors, the investigators established a protocol for inducing intermediate mesoderm from hiPSCs with up to 90% of cells positive for protein odd-skipped-related 1, which is the first step that leads to cells of the renal lineage. This study demonstrated the feasi­ bility of monitoring the nephrogenic differ­ entiation capacity of hiPSCs and provides a new strategy for investigating the efficiency and specificity of methods to obtain renal differentiation of hiPSCs. Other studies have generated germ­ line cell-derived pluripotent stem cells (GPSCs) from both human and mouse adult spermato­gonial stem cells.6 These cells share characteristics with embryonic stem cells at both the cellular and molecular level and display high plasticity—they can differentiate into hepatocytes, haemato­ poietic cells, neurons, cardiomyocytes, smooth muscle cells and endothelial cells. In a pivotal study, researchers investigated whether GPSCs derived from adult spermato­gonial stem cells could be used for renal regeneration.7 Using a novel renal epithelial cell differentiation protocol, the researchers obtained in vitro functional renal tubular-like cells from mice. Injection of GPSC-derived tubular-like cells into mice undergoing unilateral nephrectomy, followed by ischaemia–­reperfusion injury in the remaining kidney, protected against acute and chronic renal damage. These results suggest that GPSC-derived tubular- like cells are functionally active in vivo, ­enabling the repair of renal damage in a murine model of ischaemia–reperfusion injury. Such techniques open the possibil­ ity of an autologous strategy for repairing damage in acute renal disease, with the added advantage of using GPSCs directly isolated from patients (limited to males). Other potential sources of autologous or heterologous stem cells, including mesen­ chymal stem cells derived from bone marrow, adipose tissue, umbilical cord vein and placenta, have been extensively investi­ gated in preclinical models and phase I clinical trials. Despite experimental data indicating a beneficial effect of these cells in kidney regeneration, the mechanisms involved remain contro­versial. Studies in transgenic mice models suggest epithelial cells that survive after acute kidney injury can aid tubular repair.8 The paracrine theory has recently changed the interpreta­ tion of stem cell action and potential applications in regenerative medicine. Extracellular vesicles, including exosomes derived from the endosomal compartment and micro­vesicles released from the cell surface, have a key role in the interaction between stem and injured cells.9 The role of vesicles as vehicles of cell-to-cell com­ munication has been well established, with Nobel prizes awarded to Rothman, Schekman and Südhof in 2013 “for their discoveries of machinery regulating vesicle traffic, a major transport system in our cells”. Vesicles that convey extra­cellular RNA might lead to transfer of genetic infor­ mation between cells.9 Preliminary studies have demonstrated vesicles derived from mesenchymal stem cells might mimic the effect of these cells and confer a stem cell- like phenotype on injured cells, with the consequent activation of self-regenerative programmes involving cell cycle re-entry and differentiation.9 Exosomes released from human umbilical cord mesenchymal stem cells limit cis­platin nephrotoxicity by decreasing oxidative stress-induced apoptosis of renal cells, and promote proliferation of damaged tubular cells by activating the mitogen-­activated protein kinase (ERK1/2) pathway.10 This study suggests that exosomes could be exploited as a potential therapeutic tool in acute kidney injury. In conclusion, studies in 2013 have demonstrated the potential use of resident stem or progenitor cells and induced pluri­ potent stem cells for kidney regeneration. An additional alternative strategy involves stimulation of the intrinsic regenerative properties of the kidney by vesicle-induced ­reprogramming of injured cells. Department of Medical Sciences, University of Torino, Corso Dogliotti 14, 10126 Turin, Italy (L. Biancone, G. Camussi). Correspondence to: G. Camussi giovanni.camussi@unito.it Competing interests G. Camussi is a named inventor on patents US2011256111 (A1) and ES2423483 (T3). See the article online for full details of the patents. L. Biancone declares no competing interests. 1. Rangel, E. B. et al. C-Kit+ cells isolated from developing kidneys are a novel population of stem cells with regenerative potential. Stem Cells 31, 1644–1656 (2013). 2. Bussolati, B. et al. Isolation of renal progenitor cells from adult human kidney. Am. J. Pathol. 166, 545–555 (2005). 3. Sagrinati, C. et al. Isolation and characterization of multipotent progenitor cells from the Bowman’s capsule of adult human kidneys. J. Am. Soc. Nephrol. 17, 2443–2456 (2006). 4. Harari-Steinberg, O. et al. Identification of human nephron progenitors capable of generation of kidney structures and functional repair of chronic renal disease. EMBO Mol. Med. 5, 1556–1568 (2013). 5. Mae, S. et al. Monitoring and robust induction of nephrogenic intermediate mesoderm from human pluripotent stem cells. Nat. Commun. http://dx.doi.org/10.1038/ncomms2378. 6. Fagoonee, S., Pellicano, R., Silengo, L. & Altruda, F. Potential applications of germline cell-derived pluripotent stem cells in organ regeneration. Organogenesis 7, 116–122 (2011). 7. De Chiara, L. et al. Renal cells from spermatogonial germline stem cells protect against kidney injury. J.Am. Soc. Nephrol. http://dx.doi.org/10.1681/ ASN.2013040367. 8. Humphreys, B. D. et al. Intrinsic epithelial cells repair the kidney after injury. Cell Stem Cell 2, 284–291 (2008). 9. Camussi, G. et al. Exosomes/microvesicles as a mechanism of cell‑to‑cell communication. Kidney Int. 78, 838–848 (2010). 10. Zhou, Y. et al. Exosomes released by human umbilical cord mesenchymal stem cells protect against cisplatin-induced renal oxidative stress and apoptosis in vivo and in vitro. Stem Cell Res.Ther. http://dx.doi.org/10.1186/ scrt194. Key advances ■■ Stem or progenitor cells derived from neonatal or fetal kidneys have regenerative potential in acute and chronic models of kidney injury, acting either by paracrine mechanisms or by permanent engraftment1,4 ■■ New strategies have been developed to induce nephrogenic differentiation of induced pluripotent stem cells5,7 ■■ The use of extracellular vesicles derived from stem cells has been shown to be a potential therapeutic approach for acute kidney injury by stimulating endogenous kidney repair10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 55. S48 www.nature.com/nrneph/collections/xxxx NEPHROLOGY 48  |  JANUARY 2014 www.nature.com/reviews GENETICS IN KIDNEY DISEASE IN 2013 Susceptibility genes for renal and urological disorders Jasmin Divers and Barry I. Freedman In 2013, substantial progress was made in uncovering the genetic basis of a variety of kidney and urological disorders, including congenital and developmental diseases. The new findings will lead to an increased understanding of the pathophysiology of these diseases, improved risk prediction and the development of novel therapies. Divers, J. & Freedman, B. I. Nat. Rev. Nephrol. 10, 69–70 (2014); published online 3 December 2013; doi:10.1038/nrneph.2013.259 The field of nephrology has progressed far beyond the era in which the term Bright’s disease was applied indiscriminately to disorders that resulted in retention of kidney toxins. However, many urinary tract and renal parenchymal disorders con­ tinue to defy characterization and modern molecular genetics approaches hold great promise in this regard. 2013 saw several important developments in the genetics of kidney diseases, from congenital dis­ orders affecting the urinary tract to devel­ opmental diseases impacting the renal parenchyma (Figure 1). Although an inherited basis for congeni­ tal abnormalities of the kidney and urinary tract (CAKUT) has long been appreciated, disease and genetic heterogeneity, environ­ mental factors and limited sample sizes have hampered the identification of causa­ tive gene variants. In 2013, Sanna-Cherchi and colleagues performed linkage analysis in four generations of a family with auto­ somal dominant CAKUT and detected five linked genomic regions in the seven affected members.1 Using whole-exome sequence analysis of DNA from two of the affected individuals, the researchers identified a protein-changing variant in exon 2 of the DSTYK gene. This G to A mutation was present in affected individ­ uals, obligate carriers, and two seemingly unaffected family members. The mutation is associated with a heterozygous 27 base- pair deletion that causes an in-frame del­ etion of nine amino acids in a domain that is highly conserved among mammals. Additional sequence analysis of DNA from 311 ­unrelated patients with CAKUT identified five previously unreported DSTYK mutations in seven patients. The spectrum of phenotypes associated with DSTYK mutations included renal hypodysplasia, uretero­pelvic junction obstruction, and vesicoureteral reflux. DSTYK was expressed in the tubule epi­ thelia, medulla and papilla of developing murine kidneys, and on principal and intercalated cells in the apical and baso­ lateral membranes of the collecting duct in a human paediatric kidney. These findings suggest potential roles for altered develop­ ment or function of these cell types in a subset of patients with CAKUT. Autosomal dominant forms of tubulo­ interstitial nephritis are poorly understood and frequently misdiagnosed. These dis­ orders have overlapping characteristics and are often collectively described as medullary cystic kidney disease (MCKD), although cysts might not be present. In 2002, the UMOD gene locus on chromo­ some 16, which encodes uromodulin, was identified as the cause of MCKD type 2.2 The gene that causes MCKD type  1 (MCKD1) on chromosome 1 was iden­ tified in 2013. Using cloning, capillary sequencing, and de novo assembly in six families with MCKD1, Kirby and col­ leagues determined that variations in MUC1 were causative for the disease.3 The families harboured independently arising mutations in MUC1 consisting of the insertion of cytosine in one copy (different in each family) of the repeat unit forming the guanine and cytosine-­rich coding variable-number tandem repeat sequence. MUC1 encodes the transmembrane glyco­ protein mucin 1, which is expressed on distal convoluted tubule epithelial cells and has diverse functions, including roles in cell adhesion and viability. The identi­ fied mutations cause a frame shift resulting in the production of altered proteins that lack critical domains and presumably have ­abnormal functions. Common (and complex) nondiabetic nephropathies with glomerular, inter­stitial, and vascular changes result in nearly 50% of cases of end-stage renal disease (ESRD) in the USA.4 In African Americans, G1 and G2 coding variants of the APOL1 gene are strongly associated with nondia­ betic ESRD and contribute to nearly 70% of cases.5,6 APOL1 is associated with pro­ gression of nephropathy in individuals of African ancestry with idiopathic focal segmental glomerulosclerosis (FSGS), col­ lapsing FSGS, HIV-associated nephropathy, severe lupus nephritis, sickle cell nephro­ pathy, and kidney disease attributed to essential hypertension. Proximal convoluted tubule Renal artery Renal vein Kidney Glomerular capsule Cortex APOL1 FRMD3 Medulla APOL1 Ureter DSTYK Loop of Henle Renal artery Renal vein Collecting duct DSTYK Distal convoluted tubule MUC1 Thick ascending limb MUC1 UMOD Figure 1 | Renal compartments most impacted by risk variants in the APOL1, DSTYK, FRMD3, MUC1 and UMOD genes. © 2014 Macmillan Publishers Limited. All rights reserved
  • 56. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB NEPHROLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  49 Despite these important findings, the perception that mild-to-moderate sys­ temic hypertension is a common cause of nephro­pathy in African Americans stub­ bornly persists, and nephrologists often apply the empiric diagnosis of hyper­tensive nephro­pathy to nondiabetic patients with progressive nephropathy who lack heavy proteinuria, particularly if kidney biopsy samples are not available.7 The suggestion that many African Americans diagnosed with hypertensive nephropathy have a primary kidney disease in the FSGS spec­ trum and secondary hypertension is fre­ quently met with scepticism. However, the African American Study of Kidney Disease and Hypertension (AASK) resolved this controversy in 2013.8 Not only did AASK demonstrate that aggressive blood pres­ sure control with angiotensin-­converting enzyme (ACE) inhibitor-based therapy has weak effects on progression of nephropathy in African Americans (in contrast to the reported favourable effects in patients with European ancestry), but APOL1 risk variants were strongly associated with kidney disease in AASK participants. The strongest associations were detected in patients whose kidney disease progressed to serum creatin­ine concentrations >265.2 μmol/l during the study, and in those with baseline urine protein:creatinine ratios >0.6 g/g. As the AASK recruitment criteria were designed to reflect hypertensive nephropathy, and blood pressure control with ACE inhibitors failed to correlate with clinical outcomes, it can no longer be argued that hypertension is the cause of progressive nephropathy in many African Americans with non­diabetic nephropathy. In the AASK participants, only APOL1 genotypes correlated with the presence and progression of kidney disease independent of blood pressure control or medication class, proving that the disorder frequently resides in the FSGS spectrum. Now that the pathogenesis of this dis­order has been ­elucidated, rational ­therapies might emerge. The search for susceptibility genes for diabetic nephropathy has proven complex, likely because of the variable histology, differing disease definitions, and the influence of glycaemia on risk of nephropathy. The discovery that vari­ ants in loci near to the FRMD3 gene were associated with diabetic nephropathy in patients with type 1 and type 2 dia­betes mellitus in multiple populations held great promise for the identification of a susceptibility gene.9 However, the single nucleotide polymorphism (SNP) that was most strongly associated with diabetic nephropathy (rs1888747) was found near, not in FRMD3.9 In 2013, Martini and colleagues used comparative promoter analysis to identify common regulatory elements of FRMD3.10 They based their strategy on the assump­ tion that promoters of functionally linked transcripts were likely associated with a common upstream regulatory element. Pathway analy­sis of 581 genes coexpres­ sed with FRMD3 was conducted in 22 American Indians with type 2 diabetes mellitus and chronic kidney disease. This analysis demonstrated strong enrich­ ment of the bone morphogenetic protein (BMP) signalling pathway (with 8 genes represented). Unsupervised hierarchical clustering of coexpressed genes showed statistically significant differences in FRMD3 expression and associations with renal outcomes and histology. Patients with diabetic nephropathy and increasing albumin­uria or greater mesangial expan­ sion showed downregulation of BMP pathway genes, compared with patients who had less-severe diabetic nephropathy. The researchers identified a transcription factor binding site (TFBS) encompassing SNP rs1888747 that was not present in patients with normal variants. This TFBS increased binding of glomerular nuclear extracts to the genomic region associated with diabetic nephropathy. The research­ ers concluded that rs1888747 affects protein binding and hypothesized that a coregulatory relationship exists between FRMD3 and BMP pathway genes. Their novel approach provides a framework for future functional genomics analyses when genome-wide association study results suggest ­association of diseases with noncoding variants. In summary, several recent studies have elucidated the role of genetic variation in diabetic and nondiabetic forms of complex kidney disease and in tubulointerstitial and congenital kidney disorders. These develop­ments will improve disease classi­ fication and risk prediction, as well as lead to novel ­treatment approaches. Department of Biostatistical Sciences (J. Divers), Department of Internal Medicine— Nephrology (B. I. Freedman),Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA. Correspondence to: B. I. Freedman bfreedma@wakehealth.edu Acknowledgements B. I. Freedman’s work is supported in part by NIH grants RO1 DK070941 and RO1 DK084149. Competing interests The authors declare no competing interests. 1. Sanna-Cherchi, S. et al. Mutations in DSTYK and dominant urinary tract malformations. N. Engl. J. Med. 369, 621–629 (2013). 2. Hart, T. C. et al. Mutations of the UMOD gene are responsible for medullary cystic kidney disease 2 and familial juvenile hyperuricaemic nephropathy. J. Med. Genet. 39, 882–892 (2002). 3. Kirby, A. et al. Mutations causing medullary cystic kidney disease type 1 lie in a large VNTR in MUC1 missed by massively parallel sequencing. Nat. Genet. 45, 299–303 (2013). 4. U. S. Renal Data System, USRDS 2012 Annual Data Report. Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States Vol. 1, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases (Bethesda, 2012). 5. Genovese, G. et al. Association of trypanolytic ApoL1 variants with kidney disease in African Americans. Science 329, 841–845 (2010). 6. Tzur, S. et al. Missense mutations in the APOL1 gene are highly associated with end stage kidney disease risk previously attributed to the MYH9 gene. Hum. Genet. 128, 345–350 (2010). 7. Skorecki, K. L. & Wasser, W. G. Hypertension- misattributed kidney disease in African Americans. Kidney Int. 83, 6–9 (2013). 8. Lipkowitz, M. S. et al. Apolipoprotein L1 gene variants associate with hypertension-attributed nephropathy and the rate of kidney function decline in African Americans. Kidney Int. 83, 114–120 (2013). 9. Pezzolesi, M. G. et al. Genome-wide association scan for diabetic nephropathy susceptibility genes in type 1 diabetes. Diabetes 58, 1403–1410 (2009). 10. Martini, S. et al. From SNP to transcriptional mechanism: a model for FRMD3 in diabetic nephropathy. Diabetes 62, 2605-2612 (2013). Key advances ■■ Mutations in DSTYK are associated with congenital abnormalities of the kidney and urinary tract1 ■■ Mutations in MUC1 and UMOD are associated with medullary cystic kidney disease (MCKD) type 13 and MCKD type 2,2 respectively ■■ Progressive nondiabetic kidney disease in patients with African ancestry who have hypertension and low-level proteinuria often belong in the focal segmental glomerulosclerosis spectrum and strongly associate with two coding variants in APOL18 ■■ A coregulatory relationship might exist between a variant associated with diabetic nephropathy that is located near to the FRMD3 gene and bone morphogenetic pathway genes10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 57. S50 www.nature.com/nrneph/collections/xxxx NEPHROLOGY 50  |  JANUARY 2014 www.nature.com/reviews CARDIOVASCULAR DISEASE IN CKD IN 2013 Reducing cardiovascular risk —light at the end of the tunnel Jessica Kendrick and Michel Chonchol During 2013, a meta-analysis provided evidence that cystatin C improves estimated glomerular filtration rate in cardiovascular risk categorization in chronic kidney disease (CKD). Another study showed that low diastolic blood pressure (DBP) is harmful in patients with CKD, challenging the paradigm of treating elevated systolic blood pressure regardless of DBP. Overall, mortality rates in CKD have decreased but further improvement is required. Kendrick, J. & Chonchol, M. Nat. Rev. Nephrol. 10, 71–72 (2014); published online 10 December 2013; doi:10.1038/nrneph.2013.260 Chronic kidney disease (CKD) is often associ­ated with dismal clinical outcomes, which are mainly driven by high rates of cardio­vascular events. The risk of death and cardiovascular events increases as the estimated glomerular filtration rate (eGFR) declines.1 Accurate detection and staging of CKD is, therefore, crucial to appropriately treat and risk stratify patients. Creatinine- based measurements are currently used to calculate eGFR, but this has limitations in risk assessment due to non-GFR determi­ nants of serum creatinine.2 For this reason, cystatin C has received attention as an alternative marker for eGFR. In 2013, a meta-­analysis examined if the addition of cystatin C measure­ments to creatinine levels in calculating eGFR improved the risk clas­ sification for death, cardiovascular disease and end-stage renal disease (ESRD).3 16 studies (11 general population and five cohort studies of patients with CKD) were included in the analysis. Cystatin C‑based eGFR predicted increased risks of all-cause and cardio­vascular deaths that were not detected with creatinine-based calculations of eGFR. Cystatin C‑based eGFR, and eGFR from a combined measurement of creatin­ ine and cystatin C, had a constant linear relationship with adverse outcomes for all levels <85 ml/min/1.73 m2 . 42% of patients with a creatinine-­based eGFR of 45–59 ml/ min/1.73m2 had a cystatin C‑based eGFR ≥60 ml/min/1.73 m2 and the reclassified eGFR resulted in a 34% reduction in the risk of death and an 80% reduction in ESRD risk. This study provides evidence that cys­ tatin C improves the role of eGFR in risk categorization of patients with CKD. Hence, eGFR based on cystatin C or combined measurements of creatinine and cystatin C might more accurately predict stage and risk ­stratify patients with CKD. The optimal blood pressure to reduce mortality and cardiovascular events in patients with CKD remains controversial. Treatment guidelines for hypertension rec­ ommend treating elevated systolic blood pressure (SBP) regardless of diastolic blood pressure (DBP) levels.4 Patients with CKD often have low DBP due to increased vascular stiffness and atherosclerosis. Low DBP has been associated with death, but very little is known about DBP and adverse events in patients with CKD. In 2013, a large cohort study of 651,749 US veterans with CKD was undertaken to assess the associ­ ation of blood pressure with death.5 During a median follow-up of 5.8 years, 238,640 patients died. When examined separately, SBP and DBP had a U‑shaped association with mortality, with both lower and higher levels showing a considerable and signifi­ cant association with death. When exam­ ined in combinations, patients with a SBP of 130–159 mmHg combined with DBP of 70–89 mmHg had the lowest adjusted mortality rates. Participants with both low SBP and DBP (SBP <120 mmHg and DBP <80 mmHg) had the highest mortality rates. Interestingly, patients with moderately ele­ vated SBP combined with DBP >70 mmHg had lower mortality rates than patients with ideal SBP combined with DBP <70 mmHg. These associ­ations were consistent in patients both with or without protein­uria and with or without diabetes mellitus. Although restricted by the limitations of observational studies, this study suggests that lowering SBP to current guidelines of <130 mmHg (or even lower in patients with CKD) at the expense of lowering DBP to less than 70 mmHg might be harmful to those patients. Randomized controlled trials are needed to clarify the optimal blood pressure goal in patients with CKD. The National Institutes of Health-sponsored Systolic Blood Pressure Intervention Trial6 is examining if an SBP goal of <120 mmHg will reduce cardiovascular and renal events compared with an SBP goal of <140 mmHg in patients at high risk for cardiovascular disease, including many with eGFRs of 20–59 ml/min/1.73m2 . However, in this trial DBP goals are not being examined. The increased cardiovascular disease risk in patients with CKD is not fully explained by traditional cardiac risk factors. Disordered phosphate metabo­ lism has emerged as an important cardio­ vascular risk factor in patients with CKD over the past decade7 and, in 2013, a ran­ domized, double-blind, placebo-controlled trial was performed to determine if low­ ering serum phosphate and fibroblast growth factor 23 (FGF-23) concentrations improved cardiac function in patients with stage 3 non­diabetic CKD and normal serum phosphate levels.8 120 patients were randomly assigned to receive the phos­ phate binding drug sevelamer or placebo Thinkstock Key advances ■■ Cystatin C improves the role of estimated glomerular filtration rate for categorizing cardiovascular risk in patients with chronic kidney disease (CKD)3 ■■ An observational study of >600,000 patients found that lowering systolic blood pressure at the expense of lowering diastolic blood pressure might be harmful in patients with CKD5 ■■ Treatment of disordered phosphate metabolism with sevelamer in patients with stage 3 CKD did not improve left ventricular mass, function or arterial stiffness7 ■■ Mortality rates for children and adolescents on dialysis improved significantly between 1990 and 201010 © 2014 Macmillan Publishers Limited. All rights reserved
  • 58. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB NEPHROLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  51 with meals for 36 weeks after a 4‑week open-label run-in phase. After 40 weeks of treatment, no differences in left ven­ tricular mass, systolic or diastolic func­ tion, or pulse wave velo­city were detected between the two groups. Furthermore, no difference in serum FGF-23, para­thyroid hormone, 1,25‑­dihydroxyvitamin D, 25‑­hydroxyvitamin D or phosphate levels were found between participants in either trial arm. Although observational data support a relationship between disordered phosphate metabolism and cardiovascular disease in patients with normal serum phos­ phate and earlier stages of CKD, current clinical data do not support using phos­ phate binders to treat patients with stage 3 CKD to improve cardiac function or arter­ ial stiffness. Further studies are needed to elucidate the role of targeting disordered mineral meta­bolism on cardiovascular disease in patients with CKD. Clinical trials that focus on reducing cardio­vascular risk in patients with CKD are desperately needed as to date many have yielded negative results. The good news is that overall mortality in CKD has decreased dramatically in the past 20 years. Compared with results obtained in 1995, the death rate for patients with CKD in the US Medicare system has fallen 40.3%, and the adjusted death rate from CKD was 74.9 per 1,000 patient years in 2010.9 In 2013, we learned that mortality in children on dialysis has also decreased. A study of 23,401 children and adolescents who initi­ ated treatment with dialysis before the age of 21 years found that mortality rates improved significantly between 1990 and 2010.10 The magnitude of improvement in mortality was greater for children who were under 5 years at the initiation of dialysis compared with older children. However, the difference did not reach statistical sig­ nificance. Cardiovascular-related mortality progressively improved in children over the 20 year period. Between 1990 and 2010, each 5‑year increment in calendar year of initiation of dialysis was associated with a 46% reduction in risk of cardio­vascular death among children <5 years of age at initiation and 34% in children ≥5 years at initiation. Other factors probably con­ tribute to the reduced mortality in patients with CKD, including improved predialy­ sis care, advances in dialysis technology and new medications. Further research is, therefore, needed to determine the specific factors responsible for this improvement in mortality. Although this reduction in mortality is encouraging, we still have a long way to go to reduce cardiovascular morbidity and mortality in patients with CKD. Prevention and treatment of cardiovascular disease in CKD is a complex task. A multidisciplinary approach involving nephrologists, primary care physicians and cardiologists is needed in order to improve outcomes. However, the major challenge in nephrology remains the lack of therapeutic proven interventions to reduce cardiovascular disease and kidney disease progression. Division of Renal Diseases and Hypertension, University of Colorado Denver, 13199 East Montview Boulevard, Suite 495,Aurora, CO 80045, USA (M. Chonchol). Denver Health Medical Center, Denver, 660 Bannock Street, Mail Code 4000, Denver, CO 80204, USA (J. Kendrick). Correspondence to: J. Kendrick jessica.kendrick@ucdenver.edu Competing interests The authors declare no competing interests. 1. Go, A. S., Chertow, G. M., Fan, D., McCulloch, C. E. & Hsu, C. Y. Chronic kidney disease and the risks of death, cardiovascular events and hospitalization. N. Engl. J. Med. 351, 1296–1305 (2004). 2. Levey, A. S. et al. The definition, classification, and prognosis of chronic kidney disease: a KDIGO Controversies Conference Report. Kidney Int. 80, 17–28 (2011). 3. Shlipak, M. G. et al. Cystatin C versus creatinine in determining risk based on kidney function. N. Engl. J. Med. 369, 932–943 (2013). 4. Chobanian, A. V. et al. National Heart, Lung, and Blood Institute. Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation and Treatment of High Blood Pressure. Hypertension 42, 1206–1252 (2003). 5. Kovesdy, C. P. et al. Blood pressure and mortality in U.S. veterans with chronic kidney disease: a cohort study. Ann. Intern. Med. 159, 233–242 (2013). 6. US National Institutes for Health. Clinicaltrials.gov [online], http://clinicaltrials.gov/ct2/show/ NCT01206062 (2013). 7. Ellam, T. J. & Chico, T. J. Phosphate: the new cholesterol? The role of the phosphate axis in non-uremic vascular disease. Atherosclerosis 220, 310–318 (2012). 8. Chue, C. D. et al. Cardiovascular effects of sevelamer in stage 3 CKD. J. Am. Soc. Nephrol. 24, 842–852 (2013). 9. U.S. Renal Data System. USRDS 2012 Annual Data Report: Atlas of chronic kidney disease and end-stage renal disease in the United States [online], http://www.usrds.org/adr.aspx (2012). 10. Mitsnefes, M. M., Laskin, B. L., Dahhou, M., Zhang, X. & Foster, B. J. Mortality risk among children initially treated with dialysis for end- stage kidney disease, 1999–2010. JAMA 309, 1921–1929 (2013). TRANSPLANTATION IMMUNOLOGY IN 2013 New approaches to diagnosis of rejection Nicholas A. Zwang and Laurence A.Turka In 2013, a key theme of research in renal transplantation was the diagnosis of rejection. Data from key studies published in the past year highlight aspects of rejection that warrant further investigation and should prompt the consideration of adjunctive tests to complement traditional histological assessment of allograft biopsy samples. Zwang, N. A. & Turka, L. A. Nat. Rev. Nephrol. 10, 72–74 (2014); published online 17 December 2013; doi:10.1038/nrneph.2013.262 Key studies published in 2013 provide new insights into the diagnosis and mechanisms of renal transplant rejec­ tion. Novel approaches to detect acute rejection were investigated and progress was made in understanding the patho­ genicity of complement-­fixing anti-HLA antibodies and the importance of antibody-­ mediated vascular rejection in determining patient prognosis. In 2013, data from the INTERCOM trial and its lead-up studies were published.1–4 First, 403 transplant indication biopsy samples were used to develop microarray- based scores to detect T-cell-mediated rejec­ tion (TCMR)1 and ­antibody-­mediated rejection (ABMR).2 A 30-gene molecular signature of TCMR was identified, and a TCMR score assigned to each biopsy sample. These scores were then compared with the results of histological assessments from three pathologists. Inter-observer variabil­ ity in Banff scoring is a well-­documented phenom­enon,5 and the sensi­tivity for © 2014 Macmillan Publishers Limited. All rights reserved
  • 59. S52 www.nature.com/nrneph/collections/xxxx NEPHROLOGY 52  |  JANUARY 2014 www.nature.com/reviews diagnosis of TCMR or mixed rejection among the study pathologists was ≥45%.1 However, the highest TCMR scores corre­ lated with the best agreement among pathol­ ogists for the diagnosis of TCMR, and the defined cut-off score yielded a sensitivity of 50% and ­specificity of 95% for TCMR. To develop an ABMR score, the biopsy samples were phenotyped using histologi­ cal assessment and HLA antibody testing, and the associated gene-expression patterns were characterized.2 The transcripts that fea­ tured most prominently in the ABMR score were expressed in endothelial cells or natural killer (NK) cells or were induced by IFNγ, consistent with the hypothesis that NK cells mediate ABMR by interacting with donor- specific antibody (DSA)-coated allograft endothelia. Higher ABMR scores correlated with greater agreement regarding ABMR diagnosis among the pathologists, and the score performed well in lesions of peri­ tubular capillaritis and glomerulitis, with a sensitivity of 67% and a specificity of 90%. The INTERCOM trial compared histo­ logical assessments with the microarray- based TCMR and ABMR scores in 300 indication biopsy samples from 264 kidney transplant recipients.3,4 Receiver operat­ ing characteristic (ROC) analysis of the TCMR score yielded an area under the curve (AUC) of 0.84 and a specificity of 91%.3 The greatest confounders between histologi­ cal assessment and TCMR score were early post-­transplantation acute kidney injury (AKI), polyomavirus nephropathy, and iso­ lated vascular lesions. ROC analysis of the ABMR score yielded an AUC of 0.85, sensi­ tivity of 69% and specificity of 87%.4 At 3 years post-transplantation, this score had greater prognostic value for graft survival than did histological assessment. C4d staining varies substantially between lab­ oratories,6 and C4d-negative specimens with features of ABMR were a major confounder. The INTERCOM researchers propose post hoc reclassification of their histological findings based on TCMR molecular scores as follows: potential false-positive histologi­ cal assessment (isolated vascular lesions, AKI or pretreatment) and a low TCMR score do not indicate TMCR; potential false-negative histological assessment (heavy scarring or borderline) and high TCMR scores do indi­ cate TCMR. They do not suggest a similar reclassification for ABMR. The sensitiv­ ity of molecular scoring approaches for the diagnosis of TCMR might improve mark­ edly with adoption of this ­methodology, which merits further study. The importance of vascular lesions in allograft rejection, and the possibility that vascular lesions might indicate ABMR rather than TCMR, was also investigated in 2013. Lefaucheur et al. assessed evidence of endarteritis, TCMR and ABMR (using Banff criteria) in 302 biopsy samples from 2,079 patients with biopsy-proven rejection, and divided the samples into four categ­ories: T-cell-mediated vascular rejection (26 patients); antibody-mediated vascular rejec­ tion (64 patients); TCMR without vasculitis (139 patients); and ABMR without vasculi­ tis (73 patients).7 Graft survival 72 months after acute rejection was worst in patients with antibody-mediated vascular rejection (50.3% versus 82.6% for ABMR without vasculitis, 91.3% for T‑cell-mediated vascu­ lar rejection and 93.2% for TCMR without vasculitis). Notably, 52 of these patients were misclassified and treated for TCMR at the time of biopsy. These studies suggest that vascular involvement may warrant its own category in histological assessment of rejection. Perhaps the loftiest goal in rejection diag­ nostics is the development of a noninvasive approach. With this aim, Suthanthiran and colleagues carried out a multicenter study to develop a urinary mRNA profile of acute TCMR.8 They collected 4,300 urine samples from 485 kidney transplant recipients at 3 days to 12 months post-­transplant, and matched 298 of these samples with kidney- allograft biopsy samples. They found that a three-gene signature of 18S-normalized levels of CD3ε mRNA, interferon-­inducible protein 10, and 18S rRNA in the urinary sediment cells was diagnostic for acute rejection (assessed using Banff criteria) in the matched biopsy samples. In an external validation data set, ROC analysis of the three-gene signature showed an AUC of 0.74 with a sensitivity of 71% and specificity of 72% for the detection of acute rejection. The urinary mRNA signature could distin­ guish TCMR from borderline changes, acute ABMR and chronic allograft nephropathy, as well as from conditions involving T‑cell activation (urinary tract infection, septi­ caemia and cytomegalo­virus infection) but performed poorly in the presence of polyoma­virus infection. Retrospective analysis of urine samples showed a marked increase in the diagnostic signature around 20 days prior to the first biopsy sample showing acute cellu­lar rejection. The perfor­ mance of urinary mRNA testing is probably not yet adequate for widespread clinical use but the approach is promising. Serial testing might predict the need for biopsy before a decrease in allograft function becomes apparent or enable biopsy to be avoided.9 Additional urinary mRNA markers might improve the ability of this approach to ­diagnose TCMR or even ABMR. A final key finding from 2013 was the importance of complement-fixing anti-HLA antibodies in rejection.10 In a population-­ based study, kidney transplant recipients were screened for DSAs and C1q binding over a 6 year period. Among 1,016 biopsy samples obtained within the first year after transplantation, C1q fixation was associ­ ated with higher Banff scores for features of ABMR (microvascular inflammation, trans­ plant glomerulopathy, interstitial inflam­ mation and tubulitis) and increased C4d deposition in the graft. Average glomeru­ lar filtration rate 1 year after transplant­ ation was lower in patients with C1q-fixing DSAs (42 ± 22 ml/min/1.73 m2 ) than in patients with DSAs that did not bind C1q Key advances ■■ Use of microarray-based scores can improve the accuracy of diagnosis of T‑cell-mediated rejection (TCMR)1,3 and antibody-mediated rejection (ABMR)2,4 in biopsy samples ■■ Vascular lesions in biopsy samples are associated with poor prognosis in patients with ABMR7 and merit further investigation ■■ Urinary mRNA profiling shows promise as a noninvasive approach to detect and predict acute TCMR8 ■■ The presence of complement-fixing donor-specific antibodies after renal transplantation predicts poor graft outcomes10 NPG © 2014 Macmillan Publishers Limited. All rights reserved
  • 60. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB NEPHROLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  53 (51 ± 20 ml/min/1.73 m2 ). Most importantly, the presence of C1q-fixing DSAs after trans­ plantation was associated with the lowest 5‑year graft survival (54% versus 93% and 94% for patients with non‑C1q fixing DSAs and no DSAs, respectively). Even after adjusting for mean fluorescence intensity, the hazard ratio for graft loss was 4.48 (95% CI 2.69–8.49) if C1q fixation was present. These findings suggest a need to assess C1q fixation in patients with ABMR. In 2013, the limitations of traditional histological approaches and the potential of new molecular techniques for the diag­ nosis of renal allograft rejection became apparent. It would be premature to replace histological assessments of biopsy samples with molecular techniques. However, the adjuncts reviewed here (molecular scoring, urinary mRNA analysis, C1q fixation assays and assessment of vascular involve­ ment) can more-finely resolve the diag­ nostic utility of histological assessment. These adjuncts further illuminate aspects of rejection that warrant future study (such as vascular lesions) and opportunities for noninvasive diagnosis. We hope that the new findings encourage thoughtful, refined clini­cal studies in which the use of adjunctive testing ultimately improves graft ­survival and patient outcomes. Transplantation Biology Research Center, Massachusetts General Hospital, Room 5102, Charlestown, MA 02129, USA (N. A. Zwang, L. A. Turka). Correspondence to: N. A. Zwang nzwang@partners.org Acknowledgements N. A. Zwang thanks the Brigham and Women’s Hospital/Massachusetts General Hospital Joint Nephrology Fellowship Program. Competing interests L. A. Turka declares an association with the following company: Novartis. See the article online for full details of the relationship. N. A. Zwang declares no competing interests. 1. Reeve, J. et al. Molecular diagnosis of T cell- mediated rejection in human kidney transplant biopsies. Am. J.Transplant. 13, 645–655 (2013). 2. Sellarés, J. et al. Molecular diagnosis of antibody-mediated rejection in human kidney transplants. Am. J.Transplant. 13, 971–983 (2013). 3. Halloran, P. F. et al. Potential impact of microarray diagnosis of T cell-mediated rejection in kidney transplants: the INTERCOM study. Am. J.Transplant. 13, 2352–2363 (2013). 4. Halloran, P. F. et al. Microarray diagnosis of antibody-mediated rejection in kidney transplant biopsies: an international prospective study (INTERCOM). Am. J. Transplant. 13, 2865–2874 (2013). 5. Furness, P. N. et al. International variation in histologic grading is large, and persistent feedback does not improve reproducibility. Am. J. Surg. Path. 27, 805–810 (2003). 6. Mengel, M. et al. Banff initiative for quality assurance in transplantation (BIFQUIT): reproducibility of C4d immunohistochemistry in kidney allografts. Am. J.Transplant. 13, 1235–1245 (2013). 7. Lefaucheur, C. et al. Antibody-mediated vascular rejection of kidney allografts: a population-based study. Lancet 381, 313–319 (2013). 8. Suthanthiran, M. et al. Urinary-cell mRNA profile and acute cellular rejection in kidney allografts. N. Engl. J. Med. 369, 20–31 (2013). 9. Ingelfinger, J. R. & Alexander, S. I. One step closer to “Rejectostix.” N. Engl. J. Med. 369, 84–85 (2013). 10. Loupy, A. et al. Complement-binding anti-HLA antibodies and kidney-allograft survival. N. Engl. J. Med. 369, 1215–1226 (2013). ACUTE KIDNEY INJURY IN 2013 Breaking barriers for biomarkers in AKI—progress at last Dinna N. Cruz and Ravindra L. Mehta In 2013, four important papers were published that provide new insights on biomarkers in acute kidney injury (AKI). These studies demonstrate the potential for biomarkers to aid clinicians in improving the therapeutic management of patients with AKI and potentially improve patient outcomes. Cruz, D. N. & Mehta, R. L. Nat. Rev. Nephrol. 10, 74–76 (2014); published online 24 December 2013; doi:10.1038/nrneph.2013.268 Clinicians who treat patients with acute kidney injury (AKI) are faced with several questions that influence diagnostic and therapeutic decisions: has kidney injury occurred; what is the nature, sever­ ity and duration of kidney injury; has repair and recovery started; is inter­vention needed; and what is the prognosis? At present we glean the answers to these ques­ tions by evaluating sequential changes in the levels of urine output and serum cre­ atinine, but these evaluations are limited in their scope to guide therapeutic man­ agement. The emerging field of biomark­ ers specific to kidney injury holds promise for improving therapeutic management; however, the application of biomarkers in clinical practice has been limited. The past year has seen the publication of four papers that provide new insights in this field and bring us closer to implementing ­biomarkers in the clinical care of patients with AKI. Change in urine output could be viewed as a biomarker that is already available to the clinician,1 whereas novel biomarkers of AKI await further validation. Hourly urine output is a ‘biomarker’ that is measured 24 times per day in most intensive care units (ICUs), and is generally reported almost in real-time in electronic medical records. Mandelbaum et al. studied the empirical relationships between change in creatinine concentration, change in urine output, the observation period over which these changes occurred, and clinical outcomes using a detailed ICU database for 14,526 patients.2 For creatinine, the thresholds examined were an absolute increase of 8.84–88.4 μmol/l, or a relative increase of 125–400% from admission values, and observation periods were 1–7 days. For urine output, the thresholds were 0.1–1.0 ml/kg per h, for observation periods of 2–48 h. Mortality was high when there was a large absolute increase in creatinine levels regardless of the observation period, when the relative increase in creatin­ine Key advances ■■ Urine output is emerging as a robust biomarker of acute kidney injury (AKI) associated with distinct outcomes in critically ill patients2 ■■ Combining biomarkers of tissue damage with those reflecting a functional change will enable clinicians to better characterize kidney health and the time points for specific interventions4 ■■ Biomarkers of tissue damage and cell- cycle arrest pathways have been shown to predict increasing severity of AKI6 ■■ Identifying patients at high risk of developing ‘renal angina’ could potentially guide biomarker testing in the future9 © 2014 Macmillan Publishers Limited. All rights reserved
  • 61. S54 www.nature.com/nrneph/collections/xxxx NEPHROLOGY 54  |  JANUARY 2014 www.nature.com/reviews was high and the observation period was longer, and when oliguria was sustained for long periods of time. Overall, mortality increased rapidly as urine output decreased below 0.5 ml/kg per h, which lends support to urine output criteria used in current consensus definitions for AKI.3 The area under the receiver-operating characteristics curve (AUC) for urine output below 0.5 ml/ kg per h was >0.79 for mortality and >0.89 for renal replacement therapy across all the observation periods. The longer this level of urine output persisted the better was the discrimination for both outcomes. Several companies are now developing sensors for electronic monitoring of urine flow that will undoubtedly enhance clinicians’ ability to use this physiological biomarker to improve the management of AKI. However, a key caveat is to distinguish oliguria represent­ ing the normal autoregulatory response of the kidney formerly termed ‘pre-renal states’ from underlying damage. Different thresholds of change in urine output could improve the discrimination of these con­ ditions1 and the Acute Dialysis Quality Initiative group has proposed consensus recommendations that provide a novel approach to biomarker utilization in AKI.4 Biomarkers specific to the kidney can be viewed as belonging to one of two broad classes representing functional changes (for example, serum creatinine, serum cys­ tatin C and urine output) or kidney damage (for example, proteinuria, urine and serum neutrophil gelatinase-associated lipo­ calin [NGAL], kidney injury molecule 1 [KIM-1] and liver-type fatty-acid binding protein [LFABP]). Consequently, by com­ bining biomarkers of functional change and tissue damage one can characterize any patient into one of four dynamic states of kidney health (Figure 1).4 A patient could transition from one state to another and back, depending on the nature, severity and duration of the injury. This approach permits the identi­fication of a novel state of ‘subclinical’ AKI in which kidney tissue damage might occur independently of any functional change as measured by serum creatin­ine level and urine output. Alternatively, patients might be oliguric and have elevated serum creatinine levels in the absence of any alterations in biomarkers of tissue damage. For the practicing clini­ cian, this approach permits a more detailed assessment of the underlying condition of the kidney and sequential measurements could guide thera­peutic interventions. Various biomarkers of functional change and tissue damage could be used together for differential diagnosis and progno­ sis depending on the disease context, for example a combination of serum cystatin C and urine NGAL might be more informa­ tive in liver disease, whereas KIM-1 and serum creatinine level might be appropriate in patients with sepsis. Emerging evidence supports the concept of using biomarkers in this way; however, further validation is required.5 In the two-part multicenter Sapphire study, over 300 potential biomarkers in urine were examined in 522 critically ill patients during the discovery phase.6 The two top performing markers, insulin-­like growth factor-binding protein 7 (IGFBP- 7) and tissue inhibitor of metalloprotein­ ases-2 (TIMP-2), were both inducers of G1 cell cycle arrest. After sepsis or ischae­ mic injury, renal tubular cells enter a brief period of cell cycle arrest, presumably to prevent potentially damaged cells from dividing.7 In the validation phase of this study (involving 728 patients), these two biomarkers were evaluated for their ability to predict AKI (defined as Kidney Disease Improving Global Outcomes stage 2–3) within 12 h, as well as major adverse kidney events within 30 days (MAKE30 ). When used individually, urine IGFBP-7 and TIMP-2 had AUCs of 0.76 and 0.79, respectively.6 As the two markers seemed to have additive predictive value for AKI, the main validation was performed using a combination of the two. The test result is a simple multiplication of the two markers, [TIMP-2] × [IGFBP-7]. The AUC of this dual biomarker was 0.80 for AKI, performing better than previously studied biomarkers. The risk of either AKI or MAKE30 increased sharply when [TIMP-2] × [IGFBP-7] was above 0.3 and doubled when the value was over 2.0. When added to a clinical model, [TIMP- 2] × [IGFBP-7] significantly improved the prediction value for severe AKI. This study illustrates the utility of combining biomarkers to enhance their predictive and discriminatory capabilities and also highlights the potential of using biomark­ ers to identify specific molecular pathways contributing to AKI. One of the difficulties in using AKI biomarkers has been to identify which patients would benefit most from their use. Indiscriminate use of biomarker testing in patients at low risk of AKI would render the biomarker nearly useless, as well as unnecessarily increase health-care costs. In cardiology, troponin is measured in at-risk patients who present with chest pain to rule-in or rule-out acute myocardial infarc­ tion. The concept of ‘renal angina’ rep­ resents a combination of risk factors with subtle changes in creatinine, urine output and fluid overload as the equivalent of chest pain, serving as an alert for evolving AKI.8 Hypothetically when biomarkers of AKI are used in patients with renal angina, their pre­ dictive value will improve. The concept of renal angina could, therefore, potentially guide testing of biomarkers in the future. In 2013, the predictive value of renal angina was evaluated in four paediatric cohorts in ICU (total 584 patients).9 A renal angina index (RAI) was derived as the product of a risk score (1–5) and injury score (1–8) based on a percentage decrease in esti­ mated creatinine clearance from baseline, or an increase in fluid overload in the first 8 h in ICU. An RAI >8 on day 1 in ICU was considered to be positive for renal angina; the primary outcome was AKI (stage 2–3) on day 3. Sensitivity was 58–93% and speci­ ficity was 36–90% across all cohorts, and the negative predictive value (NPV) was high at 92–99%, outperforming the Pediatric Risk of Mortality (PRISM-II) score. Recently, the predictive value of the RAI was also vali­ dated in critically ill adults.10 Similar to the paediatric study, sensitivity was 92%, speci­ ficity was 62% and NPV was excellent at No functional change Functional change Established AKI Functional AKI Subclinical AKI No AKI DamageNo damage Resolution Progression Figure 1 | Proposed utilization of biomarkers in AKI. The combined use of markers of tissue function and pathology would allow patients to be profiled into one of the four quadrants. AKI is a dynamic process; therefore, sequential testing would permit delineation of the progression from one state to another with possible resolution of disease progression. The choice of markers could be based on their optimal performance in various disease states. Abbreviation: AKI, acute kidney injury. Permission obtained from Nature Publishing Group © Murray, T. P. et al. Kidney Int. 110, 22–26 (2013). © 2014 Macmillan Publishers Limited. All rights reserved
  • 62. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB NEPHROLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  55 99%. The high NPV in both of these studies suggest that patients who are negative for renal angina are unlikely to progress to severe AKI; therefore, this is a patient group in which screening for biomarkers of AKI could have low yield. Future studies need to examine the efficacy and cost-effectiveness of selective use of AKI biomarkers using the concept of renal angina. Taken together, these four studies demon­ strate the rapidly changing landscape of bio­ markers in AKI. We can now envision how biomarkers might be utilized to improve patient care. The use of biomarkers in patients at high risk of AKI would increase the likelihood of early disease recognition and of interventions. A combination of func­ tional kidney markers and tissue damage markers should enhance our ability to define appropriate time windows for inter­ ventions. Sequential testing for biomarkers and clinical evaluation would permit a better delineation of the response to interventions and, therefore, prognosis. In short, we are poised on the verge of a new phase in AKI therapeutic management that will hopefully translate into improved patient outcomes from this devastating disease. University of California, San Diego Medicine 8342, UCSD Medical Center, 200 West Arbor Drive, San Diego, CA 92103, USA (D. N. Cruz, R. L. Mehta). Correspondence to: R. L. Mehta rmehta@ucsd.edu Competing interests D. N. Cruz declares associations with the following companies and organizations: Acute Dialysis Quality Initiative, Alere, Toray. R. L. Mehta declares associations with the following companies and organizations: AbbVie, Acute Dialysis Quality Initiative, AlloCure, Astute, Baxter, CSL Behring, Cytopherx, Eli Lilly, Gambro, GlaxoSmithKline, Grifols, Thrasos Therapeutics. See the article online for full details of the relationships. 1. Mehta, R. L. Acute kidney injury: urine output in AKI—the canary in the coal mine? Nat. Rev. Nephrol. 9, 568–570 (2013). 2. Mandelbaum, T. et al. Empirical relationships among oliguria, creatinine, mortality, and renal replacement therapy in the critically ill. Intensive Care Med. 39, 414–419 (2013). 3. Kidney Disease Improving Global Outcomes. KDIGO clinical practice guidelines for acute kidney injury. Kidney Int. Suppl. 2, 8–12 (2012). 4. Murray, P. T. et al. Current use of biomarkers in acute kidney injury: report and summary of recommendations from the 10th Acute Dialysis Quality Initiative consensus conference. Kidney Int. http://dx.doi.org/10.1038/ ki.2013.374. 5. Nickolas, T. L. et al. Diagnostic and prognostic stratification in the emergency department using urinary biomarkers of nephron damage: a multicenter prospective cohort study. J.Am. Coll. Cardiol. 59, 246–255 (2012). 6. Kashani, K. et al. Discovery and validation of cell cycle arrest biomarkers in human acute kidney injury. Crit. Care 17, R25 (2013). 7. Yang, L., Besschetnova, T. Y., Brooks, C. R., Shah, J. V. & Bonventre, J. V. Epithelial cell cycle arrest in G2/M mediates kidney fibrosis after injury. Nat. Med. 16, 535–543 (2010). 8. Goldstein, S. L. & Chawla, L. S. Renal angina. Clin. J.Am. Soc. Nephrol. 5, 943–949 (2010). 9. Basu, R. K. et al. Derivation and validation of the renal angina index to improve the prediction of acute kidney injury in critically ill children. Kidney Int. http://dx.doi.org/10.1038/ ki.2013.349. 10. Cruz, D. N. et al. Renal angina syndrome and risk of severe acute kidney injury in critically ill patients. Clin. J.Am. Soc. Nephrol. (in press). © 2014 Macmillan Publishers Limited. All rights reserved
  • 63. Editors’ picks of the year Rituximab therapy in nephrotic syndrome: implications for patients’ management Aditi Sinha and Arvind Bagga Rituximab offers an alternative approach to current immunosuppressive therapies for patients with difficult-to-treat, steroid-dependent nephrotic syndrome. Rituximab therapy has been shown to induce and maintain remission in these patients; however, most data are derived from anecdotal reports or case series. This Review provides an overview of available data on the safety and efficacy of rituximab in the treatment of paediatric and adult patients with nephrotic syndrome. doi:10.1038/nrneph.2012.289 Cardiorenal syndrome: pathophysiology and potential targets for clinical management Parta Hatamizadeh, Gregg C. Fonarow, Matthew J. Budoff, Sirous Darabian, Csaba P. Kovesdy and Kamyar Kalantar-Zadeh Heart failure and renal dysfunction frequently coexist. The term cardiorenal syndrome (CRS) is frequently used to describe this scenario, but the definition of CRS has been a matter of debate and has evolved over time. Here, the authors review the concept of CRS and its evolution and classification, and describe current and future targets for the clinical management of CRS. In addition, they propose a new classification system with seven distinct categories. doi:10.1038/nrneph.2012.279 Noninsulin glucose-lowering agents for the treatment of patients on dialysis Colleen Flynn and George L. Bakris Many noninsulin glucose-lowering agents have pharmokinetic and elimination profiles that preclude their use in patients with reduced renal function. However, several of these drugs can be used safely in patients on dialysis and should be considered by physicians. In this Review, the authors provide a guide to the use of noninsulin hypoglycaemic agents for the management of diabetes in patients receiving dialysis and also discuss the monitoring of glycaemic control in these patients. doi:10.1038/nrneph.2013.12 Chronic kidney disease following acute kidney injury—risk and outcomes Kelvin C. W. Leung, Marcello Tonelli and Matthew T. James In the past few years, basic research and epidemiological studies have provided a wealth of new data on renal prognosis following acute kidney injury (AKI) and the potential association of AKI with incident chronic kidney disease (CKD), progression of CKD and incident end-stage renal disease. The authors of this Review describe these findings and discuss the possible mechanisms by which AKI might lead to CKD or CKD progression. doi:10.1038/nrneph.2012.280 Cell–matrix adhesion of podocytes in physiology and disease Norman Sachs and Arnoud Sonnenberg Podocytes, a key component of the glomerular filtration barrier, adhere tightly to the glomerular basement membrane (GBM) through the actions of extracellular ligands within the GBM, transmembrane podocyte adhesion receptors and intracellular linker proteins. This Review summarizes recent advances in our understanding of the cell biology and genetics of podocyte adhesion with a focus on its functional relevance in physiology and disease. doi:10.1038/nrneph.2012.291 Renal progenitors: an evolutionary conserved strategy for kidney regeneration Paola Romagnani, Laura Lasagni and Giuseppe Remuzzi Cellular regeneration—the repair of portions of the existing nephron after tubular damage—is conserved in all animal species. By contrast, nephron neogenesis is present in lower branches of the animal kingdom, but not in adult mammals. Converging evidence suggests that a renal progenitor system is present in the adult kidney across different stages of evolution. Here, the authors look at renal regeneration from an evolutionary perspective and suggest possible explanations for the differences between animals. doi:10.1038/nrneph.2012.290 Treatment of IgA nephropathy and Henoch–Schönlein nephritis Jürgen Floege and John Feehally Treatments administered to patients with primary IgA nephropathy (IgAN) and those with Henoch–Schönlein nephritis are largely based on opinion or weak evidence, and the recent KDIGO Clinical Practice Guidelines for Glomerulonephritis assigned low levels of evidence for the majority of recommendations and suggestions related to these two diseases. In this Review, Floege and Feehally describe an algorithm for structuring the treatment of IgAN depending on the clinical scenario, and discuss ongoing studies to investigate treatments. doi:10.1038/nrneph.2013.59 Klotho, phosphate and FGF-23 in ageing and disturbed mineral metabolism Makoto Kuro-o In this Review, the author discusses new insights into the pathogenesis of chronic kidney disease and describes a novel mechanism of ageing, both in the context of the fibroblast growth factor (FGF)–Klotho endocrine axis. In addition, the author proposes a new paradigm for dietary phosphate restriction in which phosphate restriction is started when serum FGF-23 level starts to rise, regardless of serum phosphate level. doi:10.1038/nrneph.2013.111 Treatment of idiopathic membranous nephropathy Julia M. Hofstra, Fernando C. Fervenza and Jack F. M. Wetzels Immunosuppressive treatment of patients with idiopathic membranous nephropathy is controversial because of the toxicity of the therapy and the variable natural course of the disease. In this Review, the authors discuss the 2012 Kidney Disease: Improving Global Outcomes guideline for the treatment of patients with idiopathic membranous nephropathy and highlight the remaining areas of uncertainty. doi:10.1038/nrneph.2013.125 Role of Rac1–mineralocorticoid-receptor signalling in renal and cardiac disease Miki Nagase and Toshiro Fujita This Review discusses the concept of Ras-related C3 botulinum toxin substrate 1 (Rac1)-induced activation of the mineralocorticoid receptor and highlights the available evidence for the roles of Rac1 and mineralocorticoid-receptor activation in cardiac and renal disease. The authors suggest that agents that regulate the activity of the Rac1-mineralocorticoid-receptor pathway could be novel therapeutic candidates for the treatment of chronic kidney disease and cardiac injury. doi:10.1038/nrneph.2012.282 February 2014 volume 10 no. 2 www.nature.com/reviews DIABETIC NEPHROPATHY The effect of RAAS blockade on disease progression Podocyte signal transduction Role of receptor tyrosine kinases NEPHROLOGY An official publication of nrneph_OFC_FEB14.indd 1 06/01/2014 11:57 * * * * * * * * * * A selection of articles published during 2013 in Nature Reviews Nephrology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Nephrology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 64. 56  |  JANUARY 2014 www.nature.com/reviews NEUROLOGY EPILEPSY IN 2013 Progress across the spectrum of epilepsy research Frances E. Jensen Over the past year, we have witnessed major advances in several areas of epilepsy research, including genetics and disease mechanisms, neurodevelopmental effects of antiepileptic drugs, and new therapeutic approaches based on closed-loop neurostimulator systems. The findings have important implications both for clinical practice and for future research. Jensen, F. E. Nat. Rev. Neurol. 10, 63–64 (2014); published online 14 January 2014; doi:10.1038/nrneurol.2013.277 2013 has been a remarkable year for pub- lications in the clinical, translational and basic science realms of the epilepsy field. Clinical advances were reported from large-scale, population-based genomic studies, research into mechanisms of sudden unexplained death in epilepsy (SUDEP), and investigations of the effects of in utero exposure to commonly used antiepileptic drugs (AEDs). The concept of a closed-loop neurostimulator system has become a reality—in November 2013, the FDA approved the first implantable neu- rostimulator that detects seizure onset and delivers electrical stimulation to terminate a seizure, and researchers are now moving forward with more elegant approaches involving optogenetics. These advances follow on from an impor- tant landmark in 2012: the publication of the Institute of Medicine (IOM) Report on Epilepsy.1 This report represents the first comprehensive effort by public, private and patient organizations to assess the burden of this disease. Importantly, an initial ­reanalysis of existing data in prepar­ ation for this IOM report revealed that one in 26 people will experience epilepsy at some point in their lifetime. Epilepsy can be a chronic disease, and almost 30% of people with epilepsy do not achieve full seizure control on currently available medi- cations. Beyond the seizures, about half of all patients with chronic epilepsy exhibit cognitive or psychiatric disorders. Current medical treatment options do not ‘cure’ epilepsy; they only suppress the seizures. Surgery can have disease-­modifying effects, but its invasive nature limits widespread use. Epilepsy has many aetiologies, includ- ing trauma, perinatal hypoxia–ischaemia, malformations of cortical development, tumours, toxic–metabolic status epilepti- cus, autoimmune syndrome, and genetic causes. Most idiopathic generalized epi- lepsies are thought to have a genetic com- ponent, and linkage studies, genome-wide association studies, and animal model and transgenic studies have yielded well over 100 epilepsy-associated genes. Most epi- lepsies occur in the absence of a notable family history and, to address the contri- bution of de novo mutations, a research consortium named the Epilepsy Genotype Phenotype Project and its follow-on group Epi4K2 were formed to carry out detailed phenotyping and next-generation sequen­ cing in pairs of first-degree relatives and probands, as well as in biological parents without epilepsy. In the first study from the consortium,2 de novo mutations were screened in patients with two classic epileptic encephalopathies: infantile spasms and Lennox–Gastaut syn- drome. The researchers sequenced the exomes of 264 probands and their parents, and confirmed 329 de novo mutations. Four patients had mutations in GABRB3, and ALG13 exhibited the same de novo muta- tion in two patients. Mutations in both genes showed clear statistical evidence of association with epileptic encephalopathy. Other genes with de novo mutations in the cohort included CACNA1A, CHD2, FLNA, GABRA1, GRIN1, GRIN2B, HNRNPU, IQSEC2, MTOR and NEDD4L, as well as specific gene sets that included genes regu- lated by the fragile X protein. This novel approach suggests that a substantial pro- portion of epileptic encephalopathy cases have a genetic basis, and many different mutations are likely to account for this broad class of epilepsies. The level of sci- entific accuracy could be attributed to the size of the team, which included experts in paediatric neurology, molecular genetics, engineering, information technology, and public health policy. Another large-scale project addressed the causes of SUDEP, via a consortium aptly named MORTEMUS (MORTality in Epilepsy Monitoring Unit Study).3 Recent studies have revealed that SUDEP accounts for four out of every 1,000 deaths in patients with uncontrolled epilepsy, representing a 12% cumulative risk over 40 years for patients with uncontrolled childhood-onset epilepsy.4 The mecha- nisms underlying SUDEP are poorly understood, but basic research suggests potential decreases in brainstem systems Mopic|Dreamstime.com © 2014 Macmillan Publishers Limited. All rights reserved
  • 65. KEY ADVANCES IN MEDICINE JANUARY 2014  |  57 NEUROLOGY controlling sensitivity to hypoxaemia– hypercapnia, and central control of cardiac rhythm.5 These hypotheses have had little clinical support, however, as the diagnosis was often made postmortem. The MORTEMUS report describes, with astonishing accuracy, retrospective monitoring data obtained in real time while patients with refractory epilepsy succumbed to SUDEP during routine monitoring for presurgical assessment.3 Many of these patients were intention- ally being withdrawn from their AEDs to elucidate the location of their epilep- tic focus. In view of the rarity of SUDEP, MORTEMUS obtained recordings of SUDEP and near-SUDEP events from epilepsy monitoring units from all over the world. The investigators identified a pattern of events leading up to death fol- lowing secondary generalized tonic–clonic seizures, with initially rapid breathing fol- lowed within a few minutes by transient or terminal combined cardiorespiratory dysfunction. For the first time, these clini- cal data suggest early postictal centrally mediated cardiorespiratory dysfunction. The study also identified factors that were associ­ated with avoidance of SUDEP, including video-EEG monitoring, round- the-clock supervision, pulse ­oximetry, and ­electrocardiographic monitoring. Epilepsy in pregnancy is always a therapeutic challenge, and previous studies have described many dysmorph­ isms related to specific AEDs, but little is known about effects on cognition. NEAD (Neurodevelopmental Effects of Antiepileptic Drugs) is the largest prospec- tive investigation of the cognitive effects of fetal AED exposure to date.6 The study followed 305 pregnancies, and evaluated IQ at 6 years of age, as well as other cognitive variables, adjusted for maternal IQ, AED type, standardized dose, gestational birth age, and use of peri­conceptional folate. Dose-dependent effects on IQ, verbal and non­verbal ability, memory, and executive function were observed for valproate but not for lamotrigine, phenytoin or carba­ mazepine. Animal studies have shown that exposure of the perinatal brain to certain AEDs, including valproate, results in an increase in constitutive apoptosis, and alters synaptic and growth factor gene expression.7 Taken together, these results point to a compelling need for more ­translational research in this area. In November 2013, the FDA approved the first implantable responsive neuro- stimulator connected to depth or subdural leads placed in cortical seizure foci.8 The neuro­stimulator continually senses electro­ corticographic activity, and is programmed by the physician to detect patient-specific abnormal electrocorticographic activ- ity and then provide stimulation to abort seizure activity. This approach could provide an alternative to surgery for some patients with medically refractory epilepsy. While this device is an important techno- logical breakthrough, there are obvious limitations, including nonspecific effects of electrical stimulation. To address these limitations, researchers are taking an exciting new direction; namely, the appli- cation of ­optogenetics to the problem of focal epilepsy. Paz et al.9 used optogenetic stimula- tion of the thalamus to suppress seizure activity in a rat model of seizures due to cortical stroke with secondary thalamic damage. The thalamic damage consisted of decreased ascending inhibitory output to the cortex, owing to reduced excit- ability and excit­ation in the inhibitory reticular thalamic neurons. Hence, the intrathalamic network was hyperexcit- able, generating epileptiform oscillations and thalamocortical epilepsy in injured animals. The group used a closed-loop system to detect seizures and trigger optogenetic stimulation to the affected thalamic area. In response to the post- stroke seizures, yellow light was deliv- ered intracranially, via a fibre-optic cable, to cells expressing the inhibitory opsin NpHR, which in turn aborted the sei- zures. Another important aspect of this study was that optogenetics was used to map circuitry, revealing that subcortical structures such as the thalamus critically regulate the cortex. In another recent study,10 a similar on- demand approach was used in a rodent model of temporal lobe epilepsy. In this case, targeting was accomplished via the excitatory opsin ChR2 in parvalbumin- expressing inhibitory interneurons in the hippocampus. Taken together, these studies show that optogenetics can be used to target either excitation or inhib­ ition in a cell-­specific manner, possibly avoiding some of the nonspecific effects of electrical stimulation, and paving the way for ­circuit-specific nonpharmacological therapy in epilepsy. Department of Neurology, Perelman School of Medicine, University of Pennsylvania, 3400 Spruce Street, 3rd Floor Gates Building, Philadelphia, PA 19104‑4283, USA. frances.jensen@uphs.upenn.edu Competing interests The author declares no competing interests. 1. Institute of Medicine. Epilepsy across the spectrum: promoting health and understanding. The National Academies Press,Washington, DC [online], http://books.nap.edu/ openbook.php?record_id=13379 (2012). 2. Epi4K Consortium & Epilepsy Phenome/ Genome Project. De novo mutations in epileptic encephalopathies. Nature 501, 217–221 (2013). 3. Ryvlin, P. et al. Incidence and mechanisms of cardiorespiratory arrests in epilepsy monitoring units (MORTEMUS): a retrospective study. Lancet Neurol. 12, 966–977 (2013). 4. Sillanpää, M. & Shinnar, S. Long-term mortality in childhood-onset epilepsy. N. Engl. J. Med. 363, 2522–2529 (2010). 5. Sowers, L. P., Massey, C. A., Gehlbach, B. K., Granner, M. A. & Richerson, G. B. Sudden unexpected death in epilepsy: fatal post-ictal respiratory and arousal mechanisms. Respir. Physiol. Neurobiol. 189, 315–323 (2013). 6. Meador, K. J. et al. Fetal antiepileptic drug exposure and cognitive outcomes at age 6 years (NEAD study): a prospective observational study. Lancet Neurol. 12, 244–252 (2013). 7. Turski, C. A. & Ikonomidou, C. Neuropathological sequelae of developmental exposure to antiepileptic and anesthetic drugs. Front. Neurol. 3, 120 (eCollection 2012). 8. Morrell, M. J. & RNS System in Epilepsy Study Group. Responsive cortical stimulation for the treatment of medically intractable partial epilepsy. Neurology 77, 1295–1304 (2011). 9. Paz, J. T. et al. Closed-loop optogenetic control of thalamus as a tool for interrupting seizures after cortical injury. Nat. Neurosci. 16, 64–70 (2013). 10. Krook-Magnuson, E., Armstrong, C., Oijala, M. & Soltesz, I. On-demand optogenetic control of spontaneous seizures in temporal lobe epilepsy. Nat. Commun. 4, 1376 (2013). Key advances ■■ The Epi4K Consortium identified a plethora of de novo mutations that are associated with epileptic encephalopathies2 ■■ The MORTEMUS report demonstrated a role for early postictal centrally mediated cardiorespiratory dysfunction in sudden unexpected death in epilepsy3 ■■ The NEAD study found that in utero exposure to valproate, but not lamotrigine, phenytoin or carbamazepine, has dose-dependent effects on cognition6 ■■ Optogenetics can be used to target either excitation or inhibition in a cell-specific manner, paving the way for circuit- specific nonpharmacological therapy in epilepsy9,10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 66. 58  |  JANUARY 2014 www.nature.com/reviews NEUROLOGY MOVEMENT DISORDERS IN 2013 Diagnosing and treating PD —the earlier the better? François Tison and Wassilios G. Meissner When the motor symptoms of Parkinson disease (PD) manifest, the underlying pathological processes have already caused irreversible damage. Research breakthroughs in 2013 support the importance of diagnosing PD in the prodromal phase, suggest biomarkers that could help in identifying patients at high risk of PD, and improve upon current deep brain stimulation strategies. Tison, F. & Meissner, W. G. Nat. Rev. Neurol. 10, 65–66 (2014); published online 7 January 2014; doi:10.1038/nrneurol.2013.273 Movement disorders encompass a large variety of conditions that can express as hypokinesia, such as that observed in Parkinson disease (PD), or hyperkinesia, such as that seen in dystonia, chorea and tics. An imbalance in the signal outflow of the indirect and direct basal ganglia path- ways is thought to underlie hypokinetic and hyperkinetic movement disorders. According to this model, volun­tary move- ment is facilitated by the direct pathway and inhibited by the ­indirect pathway. An alter- native, so-called surround inhibition model suggests that the direct pathway enables focused selection of deliberate movements, whereas the ­indirect pathway inhibits com- peting motor programmes. These concepts have been challenged in 2013 by the results of a study by Cui and co-workers,1 who developed an elegant in vivo mouse model to measure the activity of direct and ­indirect pathways during movement. They found concurrent activation of stri­atal projecting neurons from both pathways that preceded the initi­ation of movement, thereby chal- lenging the traditional view of basal ganglia function and pathophysiology1 and pro- viding a functional dimension to previous ­anatomical findings in nonhuman primates.2 The year 2013 was also marked by find- ings that might affect the diagnostic criteria for PD and future treatment develop­ment, and can be summarized as ‘the earlier, the better’. According to the current ‘prion- like propagation’ hypothesis of PD patho­ genesis,3 α‑synuclein accumulates and forms intraneuronal Lewy bodies in the lower brain stem (dorsal nucleus of the vagus) and olfactory bulbs. These areas are in contact with the environment through the gut and nasal cavity, so an environ­mental cause of PD remains a possibility. From there, α‑synuclein spreads to multiple brain areas, including the substantia nigra and cortex. In line with this hypothesis, results by Recasens et al.3 demonstrated propaga- tion of α‑synuclein in the brains of mice and nonhuman primates that received intra­ cerebral injections of Lewy body-enriched fractions from nigral samples taken from postmortem PD brains. According to the prion-like propaga- tion model, the pathological processes that underlie PD begin long before clinical diagnosis. Currently, diagnosis is based on motor signs, which become apparent only in advanced-stage disease. Similarly to focusing on the prodromal phase and mild cognitive impairment in Alzheimer disease, increased efforts are being made towards diagnosing PD at the prodromal, pre­ motor phase—that is, when only nonmotor symptoms such as hyposmia, gastrointesti- nal dysfunction, depression and rapid eye movement sleep behaviour disorder (RBD) are observed.4 Supporting the trend towards prodromal diagnosis, evidence suggests that inter­ vention in early motor-phase PD might be too late to protect striatal dopaminergic terminals from destruction. Kordower et al. used an impressive quantitative assessment of striatal dopaminergic fibre density that took into account confounding factors, such as tissue shrinkage. They performed cell counts of nigral tyrosine-hydroxylase- positive and melanin-positive neurons in 28 patients aged 43–89 years who died 1–27 years after diagnosis of PD. Of note, this postmortem study did not find any remaining dopamin­ergic terminals in the putamen of patients with PD who had been diagnosed ≥4 years before death.5 The best clinical indicator of premotor PD is RBD.4 Several studies have demon- strated that patients who have idiopathic RBD often go on to develop a synuclein­ opathy (PD, diffuse Lewy body disease or multiple system atrophy),6 with the rate of conversion increasing with the length of follow-up. A study in which a series of 44 patients with RBD was followed up for up to 14 years reported that 36 individuals (82%) developed a defined neurodegenera- tive disease. Among these patients, 16 had a diagnosis of PD, which was confirmed post- mortem in two patients.6 Moreover, four patients with RBD who were free of motor or cognitive symptoms showed decreased striatal dopamine transporter (DAT) uptake, impaired olfaction, or substantia nigra hyperechogenicity, confirming the potential of these markers for ­identification of patients at high risk of PD. The low specificity of some premotor symptoms such as hyposmia and gastro­ intestinal dysfunction, the time lag to manifestation of PD motor signs and the limited accuracy of biomarkers currently preclude a feasible disease-modifying or neuro­protective intervention trial that would target a population at a high risk of converting to motor PD. Given the above limitations, testing a disease-­modifying therapy in treatment- naive patients with PD who have been diagnosed recently (within 2 years) seems a valid approach, as proposed by the delayed- start clinical trial design. This trial design enables assessment of disease-modifying Key advances ■■ α-Synuclein species isolated from Lewy bodies of patients with Parkinson disease (PD) are pathogenic and can initiate a PD‑like pathological process in naive mice and nonhuman primates3 ■■ Damage to the dopaminergic nigrostriatal pathway is complete within 4 years after diagnosis of PD5 ■■ Premotor symptoms (such as rapid eye movement sleep behaviour disorder) might push the focus of translational research towards early diagnosis and the definition of prodromal premotor PD6 ■■ Early intervention trials using delayed start design are valid to assess disease- modifying effects7 ■■ Early deep brain stimulation improved quality of life in patients with PD compared with best available medical therapy alone8 ‘‘…intervention in early motor- phase PD might be too late to protect … dopaminergic terminals from destruction ’’ © 2014 Macmillan Publishers Limited. All rights reserved
  • 67. KEY ADVANCES IN MEDICINE JANUARY 2014  |  59 NEUROLOGY effects of a compound by disentangling disease course modification from sympto­ matic effects of a drug. Ironically, a negative trial that explored putative disease-­ modifying effects of ­parmipexole—­a dopa- mine agonist with known symptomatic action—provided support for the use of the delayed-start design in early PD.7 Patients in the early start group (n = 210, 6–9 months before delayed start) did not do better at 15 months than those in the delayed start group (n = 200)—an observation that could not be explained by a floor effect or insuffi- cient washout period. Of note, DAT imaging in a subgroup of patients showed similar results. The only pitfall of this trial was a higher dropout rate in the delayed-start group (22%) than in the early-start group (15%), which was attributable to worsening of PD in 10% and 2% of cases, respectively. Deep brain stimulation (DBS) is the major therapeutic breakthrough of the past 25 years for the management of PD. DBS is usually offered patients who have severe motor fluctuations or debilitating tremor despite optimal medical treatment. A large randomized controlled trial (EARLYSTIM) involving multiple centres in Germany and France assessed the efficacy of DBS of the subthalamic nucleus combined with best available medical treatment in 251 patients who were younger and had less advanced disease than those currently selected for DBS.8 The mean age of enrolled patients was 52 years, with mean disease duration of 7.5 years and mean duration of motor com- plications of 1.7 years. The study reached its primary end point: quality of life as assessed by the 39-Item PD Questionnaire was con- siderably improved after 24 months in patients receiving DBS compared with the group receiving medical treatment alone. Several secondary outcomes also favoured DBS. Whether these results will change current clinical practice and substantially increase the number of patients with PD who receive DBS is, however, uncertain, at least in the short term. A retrospective analysis of a cohort of patients with PD from a tertiary centre showed that only 2.5% of the cohort met the EARLYSTIM criteria, possibly because patients in tertiary centres usually have more advanced PD.9 Convincing general neurologists to refer their patients early enough for DBS to yield the maximum benefit could be a challenge. Finally, current DBS protocols were devel- oped empirically and do not take account of the latest discoveries in PD pathophysiol- ogy—that is, abnormal synchronization of neuronal activity in basal ganglia and corti- cal networks. In an elegant clinical proof-of- concept study, targeting of the subthalamic nucleus with adaptive DBS—which delivers electrical stimulation only when abnormal local field potential activity is detected— was more effective in improving motor symptoms than standard DBS, even though the overall stimulation time was reduced by 50%.10 Findings in 2013 continue to shift the definition of PD towards earlier, premotor phases, which could facilitate administra- tion of putative disease-modifying therapies before most nigrostriatal dopamine neurons have undergone irreversible damage. An earlier diagnosis might also increase the chance to attenuate or stop the prion-like propagation of α‑synuclein toxicity. The results of the EARLYSTIM trial suggest that standard DBS could also be beneficial in early PD. Finally, pathophysiology-driven adaptive DBS techniques are challenging the traditional DBS designs and might become a reality in clinical practice in the near future. Institut des Maladies Neurodégénératives, CHU de Bordeaux, CNRS UMR5293, Université Bordeaux, place Amélie Raba-Léon, 33076 Bordeaux cedex, France (F. Tison, W. G. Meissner). Correspondence to: F.Tison francois.tison@chu-bordeaux.fr Competing interests The authors declare associations with the following companies/organizations: Boehringer Ingelheim, GlaxoSmithKline, Novartis, Teva/Lundbeck, UCB. F. Tison declares associations with the following companies: Abbot and Addex. W. G. Meissner declares associations with the following companies/ organizations: Adaptive Neuromodulation, APTES, PSP-France. See the article online for full details of the relationships. 1. Cui, G. et al. Concurrent activation of striatal direct and indirect pathways during action initiation. Nature 494, 238–242 (2013). 2. Lévesque, M. & Parent, A. The striatofugal fiber system in primates: a reevaluation of its organization based on single-axon tracing studies. Proc. Natl Acad. Sci. USA 102, 11888–11893 (2005). 3. Recasens, A. et al. Lewy body extracts from Parkinson’s disease brains trigger α‑synuclein pathology and neurodegeneration in mice and monkeys. Ann. Neurol. http://dx.doi.org/ 10.1002/ana.24066. 4. Berg, D. et al. Changing the research criteria for the diagnosis of Parkinson’s disease: obstacles and opportunities. Lancet Neurol. 12, 514–524 (2013). 5. Kordower, J. H. et al. Disease duration and the integrity of the nigrostriatal system in Parkinson’s disease. Brain 136, 2419–2431 (2013). 6. Iranzo, A. et al. Neurodegenerative disease status and post-mortem pathology in idiopathic rapid‑eye‑movement sleep behaviour disorder: an observational cohort study. Lancet Neurol. 12, 443–453 (2013). 7. Schapira, A. H. et al. Pramipexole in patients with early Parkinson’s disease (PROUD): a randomised delayed-start trial. Lancet Neurol. 12, 747–755 (2013). 8. Schuepbach, W. M. et al. Neurostimulation for Parkinson’s disease with early motor complications. N. Engl. J. Med. 368, 610–622 (2013). 9. Sprenger, F., Seppi, K., Wolf, E. & Poewe, W. Relevance of EARLYSTIM in a tertiary movement disorder center. Mov. Disord. http:// dx.doi.org/10.1002/mds.25631. 10. Little, S. et al. Adaptive deep brain stimulation in advanced Parkinson disease. Ann. Neurol. 74, 449–457 (2013). STROKE IN 2013 Disappointments and advances in acute stroke intervention Michael Tymianski Clinical trials in stroke intervention during the past year have yielded contrasting results. Endovascular therapies and procedures to reduce stroke risk caused by patent foramen ovale have failed to demonstrate superiority over standard medical treatments. By contrast, a trial of neuroprotection— traditionally thought to be ineffective in humans—offers hope. Tymianski, M. Nat. Rev. Neurol. 10, 66–68 (2014); published online 7 January 2014; doi:10.1038/nrneurol.2013.271 Stroke affects 15 million individuals annually worldwide, incurring enormous socio­economic costs. Accordingly, stroke interventions have the potential to make a substantial impact on world health. During the past year, the completion of much-anticipated randomized controlled trials has turned the tables on preconceived © 2014 Macmillan Publishers Limited. All rights reserved
  • 68. 60  |  JANUARY 2014 www.nature.com/reviews NEUROLOGY notions about stroke treatment. Most of the trials tested endovascular inter­ventions that the medical community anticipated to be validated. Disappointingly, three trials of endovascular recanalization of occluded intracranial arteries during acute ischaemic stroke (AIS),1,2,3 and two trials of percutan­eous closure of patent foramen ovale (PFO) to prevent embolic strokes,4,5 have failed to demonstrate superiority over existing medical therapy. By contrast, a trial of neuro­protection­—a strategy that had previously failed to demonstrate ben- efits in patients with stroke—provided evidence of efficacy,6 suggesting a way forward that might positively affect the prospects of both ­neuroprotection and endovascular treatments. Arterial recanalization is a strong surro- gate measure for clinical outcome in AIS. Presently, tissue plasminogen activator (tPA) is the only widely approved recanal­ ization therapy, but early tPA administra- tion achieves recanalization rates of only 40–50% within 6 h of stroke onset,7 and the rates are even worse if the occlusion affects the internal carotid or proximal middle cer- ebral artery. Endovascular therapies, which achieve high recanalization rates, were thus hypothesized to improve clinical outcomes in AIS. The IMS III trial1 examined the ben- efits of endovascular recanal­ization in 656 patients to whom intravenous tPA was given within 3 h of stroke onset. Patients received either intravenous tPA alone or intravenous tPA followed by endovascular treatment. The primary outcome was 90-day modi- fied Rankin Scale (mRS) score of ≤2, indi- cating functional indepen­dence. The study planned to enrol up to 900 participants, but was discontinued early due to futility. Although endovascular therapy yielded higher recanalization rates, clinical out- comes after assignment of 656 parti­cipants were similar in the two groups. The authors propose that the delays in initi­ating endo- vascular therapy might have ­contributed to the negative study result. In the SYNTHESIS Expansion trial2 , 362 patients with AIS were randomly allocated to endovascular therapy or to intravenous tPA within 4.5 h of symptom onset. The primary outcome was an mRS score of 0–1 at 3-month follow-up. The groups differed in that the median time from stroke onset to the start of treatment was 1 h greater (3.75 h) for endovascular therapy than for intravenous tPA (2.75 h). Unfortunately, endovascular intervention did not prove superior to intravenous tPA. Although recanalization indicates better outcomes after AIS, and endovascular treat- ment achieves high recanalization rates, the IMS III and SYNTHESIS Expansion trials attest that even effective recanalization is futile if it occurs too late. A stroke inter­ vention can only be effective if given while salvageable brain tissue is still present. Insights regarding the ­therapeutic window in the average AIS could be obtained from existing tPA trials, which suggest that the strongest benefit is gained when thrombolysis is initiated within 3 h of stroke onset. This ~3 h window is also suggested by recent studies in gyren­ cephalic primates, which indicated that the ischaemic penumbra—­the target of stroke therapy—shrinks rapidly over 3 h so that tissue salvage past this timeframe might not be clinically effective (Figure 1).8 The MR RESCUE trial3 evaluated whether pen­umbra imaging could be used to select patients who would benefit from endovascular therapy. Patients were ran- domly assigned within 8 h of stroke onset to endovascular embolectomy or stand- ard care (which included tPA for patients who qualified for this treatment accord- ing to the standard criteria), and were stratified according to whether imaging demonstrated a favourable penumbral pattern (substantial salvageable tissue and small infarct core) or a non-penumbral pattern (large core or small or absent pen­ umbra). The primary outcome was based on the 3‑month mRS score. Unfortunately, embolectomy was not sup­erior to standard care in patients with either a favourable or a non-favourable penumbral pattern. Thus, although the penumbra is an impor- tant target for stroke treatment, it should not be confused with a selection criterion for embolectomy. The IMS III, SYNTHESIS Expansion and MR RESCUE trials provide the impetus to re-examine the indications for endovascu- lar stroke therapy. At the very least, they have restored equipoise to the treatment paradigm and could facilitate the success of future trials. By using new devices that yield improved recanalization rates, and an opti- mized workflow that minimizes the interval between symptom onset and reperfusion, the efficacy of endo­vascular therapy might be validated in a more reliable manner. PFO is found in ~25% of people, increas- ing to ~50% in patients who sustain crypto­ genic ischaemic strokes.4 Many patients with stroke who are found to have PFO undergo percutaneous closure procedures to prevent further strokes, even though the PFO could be incidental. In 2013, two eagerly awaited studies compared the benefits of PFO closure with standard medical treatment. The RESPECT trial4 and the PC Trial5 were multinational randomized controlled trials. Patients were enrolled if they had PFO plus ischae­mic stroke, transient ischaemic attack (TIA), a peripheral thrombo­embolic event (RESPECT trial only), or prior cryptogenic 2 4 6 Time (h) DWIvolume (%ofperfusiondeficitvolume) 80 80 60 40 20 0 100Figure 1 | Evolution of the ischaemic core over time in cynomolgus macaques with AIS caused by middle cerebral artery occlusion. The ischaemic core was defined as the brain volume that caused increased signal intensity on DWI MRI. The data shown are from three macaques. The solid line represents the best-fit curve. Each dot represents a single volume measurement. The DWI signal reaches a plateau ~3 h after ischaemia onset (0 h). Adapted, with permission from Nature Publishing Group © Cook, D. J. et al. Nature 483, 213–217 (2012).8 Abbreviations: AIS, acute ischaemic stroke; DWI, diffusion-weighted imaging. ▶ Key advances ■■ The IMS III1 and SYNTHESIS Expansion2 trials re-enforced the idea that recanalization of blocked arteries, no matter how effective, cannot be of benefit if it occurs too late ■■ Furthermore, IMS III and SYNTHESIS Expansion trials corroborated the notion that the targeting window for acute stroke therapies is likely to be in the order of 3 h1,2 ■■ The RESPECT trial4 and the PC Trial5 failed to resolve the controversies surrounding the efficacy of patent foramen ovale closure to prevent cryptogenic strokes ■■ The ENACT trial provided the first evidence that neuroprotection in the adult human brain is possible after the onset of ischaemic brain injury6 © 2014 Macmillan Publishers Limited. All rights reserved
  • 69. KEY ADVANCES IN MEDICINE JANUARY 2014  |  61 NEUROLOGY ischaemic stroke (PC Trial only). Patients were randomly assigned to PFO closure or to medical therapy. The trial end points included death, nonfatal stroke, TIA or peripheral embolism. Both trials followed the 909-patient CLOSURE I trial,9 which suggested no benefit of PFO closure over medical therapy for stroke or TIA prevention. The PC Trial (414 patients) also failed to show a benefit of PFO closure.5 In the RESPECT trial (980 patients), no significant benefit of PFO closure was observed in the primary intention-­to-treat analysis, but closure was superior to medical therapy in the per- protocol and as-treated analyses.4 Taken together, the CLOSURE I, RESPECT and PC Trials are unlikely to convince sceptics of the benefits of PFO closure in patients with cryptogenic stroke, although RESPECT provides a potential positive signal that could be investigated further given the equipoise between percutaneous intervention and medical treatment. Neuroprotection for AIS is defined as a therapy aimed at enhancing the brain’s resilience to ischaemia to improve clinical outcome. Half a century of neuroprotec- tion research has failed to translate over 1,000 experimental treatments to clinical utility,10 but the ENACT trial6 might have finally provided a positive signal. ENACT explored whether administration of the PSD95 inhibitor NA‑1 (also known as Tat- NR2B9c)8 after stroke onset could reduce ischaemic brain damage in patients under- going endovascular brain aneurysm repair. Such individuals have a high incidence of small procedurally induced ischaemic strokes. 185 participants were enrolled in a multicentre, randomized, double-blinded trial, and received a single intravenous infusion of NA‑1 or saline (as a control) after the endovascular procedure. Patients who received NA‑1 sustained markedly fewer ischaemic infarcts, as gauged by MRI. Among those patients with ruptured aneurysms, NA‑1 reduced the number and volume of strokes and improved neuro­ logical outcome at 30 days. This trial provides the first evidence that neuro­ protection in the ischaemic human brain is feasible and measurable, and sets the stage for future trials to improve AIS outcomes via monotherapy or in combination with ­recanalization strategies. The past year has provided a sobering reminder of the challenge of subjecting stroke interventions to rigorous scientific scrutiny, even when they are intuitively accepted in common medical practice. Nonetheless, each advance discussed above contributes to future studies in stroke research, and aids improvement of ­outcomes for patients with stroke. Toronto Western Hospital, Division of Neurosurgery, 4W‑435, 399 Bathurst Street, Toronto, ON M5T-2S8, Canada. mike.tymianski@uhn.ca Competing interests M. Tymianski declares an association with the following company: NoNO. See the article online for full details of this relationship. 1. Broderick, J. P. et al. Endovascular therapy after intravenous t-PA versus t-PA alone for stroke. N. Engl. J. Med. 368, 893–903 (2013). 2. Ciccone, A. et al. Endovascular treatment for acute ischemic stroke. N. Engl. J. Med. 368, 904–913 (2013). 3. Kidwell, C. S. et al. A trial of imaging selection and endovascular treatment for ischemic stroke. N. Engl. J. Med. 368, 914–923 (2013). 4. Carroll, J. D. et al. Closure of patent foramen ovale versus medical therapy after cryptogenic stroke. N. Engl. J. Med. 368, 1092–1100 (2013). 5. Meier, B. et al. Percutaneous closure of patent foramen ovale in cryptogenic embolism. N. Engl. J. Med. 368, 1083–1091 (2013). 6. Hill, M. D. et al. Safety and efficacy of NA-1 in patients with iatrogenic stroke after endovascular aneurysm repair (ENACT): a phase 2, randomised, double-blind, placebo- controlled trial. Lancet Neurol. 11, 942–950 (2012). 7. Rha, J. H. & Saver, J. L. The impact of recanalization on ischemic stroke outcome: a meta-analysis. Stroke 3, 967–973 (2007). 8. Cook, D. J., Teves, L. & Tymianski, M. Treatment of stroke with a PSD-95 inhibitor in the gyrencephalic primate brain. Nature 483, 213–217 (2012). 9. Furlan, A. J. et al. Closure or medical therapy for cryptogenic stroke with patent foramen ovale. N. Engl. J. Med. 366, 991–999 (2012). 10. O’Collins, V. E. et al. 1,026 experimental treatments in acute stroke. Ann. Neurol. 59, 467–477 (2006). NEURO-ONCOLOGY IN 2013 Improving outcome in newly diagnosed malignant glioma Michael Weller and Wolfgang Wick In 2013, two discoveries—that alkylating agent chemotherapy prolongs survival when added to radiotherapy for patients with anaplastic oligodendroglial tumours with 1p19q codeletion, and that bevacizumab prolongs progression-free survival in patients with newly diagnosed glioblastoma—have dominated debate in neuro-oncology. These findings could help to define new standards of care in malignant glioma. Weller, M. & Wick, W. Nat. Rev. Neurol. 10, 68–70 (2014); published online 14 January 2014; doi:10.1038/nrneurol.2013.268 Anaplastic gliomas (WHO grade III) and glioblastomas (WHO grade IV) are collectively termed malignant gliomas. Morphological subclassification of anaplas- tic gliomas into astrocytic, oligo­dendroglial and oligoastrocytic (mixed) types is chal- lenging and requires molecular guidance, but has major prognostic significance. By contrast, morphological subtyping of glioblastoma has no impact on clinical decision-making. Major advances in the diagnosis and management of malignant gliomas came with the clarification of the prognostic versus predictive role of three molecular markers: 1p19q ­codeletion, O6 -methylguanine-DNA methyl­transferase (MGMT) promoter methy­lation, and isocitrate dehydrogenase (IDH) 1 or 2 mutation.1 High-­throughput studies have further refined the molecular clas- sification and somatic genomic landscape of glioblastoma.2,3 Maximal safe surgery, as feasible, followed by radiotherapy of the involved brain region, remained the standard of care for malignant gliomas for decades until the introduction of temozolomide (TMZ) chemoradio­therapy (TMZ/RT→TMZ) for newly diagnosed glio- blastoma in 2005. The latest results of four major clinical trials, as reported in 2013, suggest further options for the treatment of malignant glioma. Long-term follow-up of patients from two randomized clinical trials—European Organization for Research and Treatment of Cancer (EORTC) 26951 and Radiation © 2014 Macmillan Publishers Limited. All rights reserved
  • 70. 62  |  JANUARY 2014 www.nature.com/reviews NEUROLOGY Therapy Oncology Group (RTOG) 9402— demonstrated a major increase in median survival when procarbazine, lomustine and vincristine (a combination termed PCV) were added to radiotherapy in patients with newly diagnosed anaplastic oligodendro­glial tumours with 1p19q codeletions.4,5 These findings contrast with the initial reports from 2006, which indicated no significant difference in outcome between radio­ therapy and combined-modality treatment. This discrepancy is perhaps best explained by the existence of two or more distinct subgroups of patients within the cohort of patients with 1p19q-codeleted tumours, with one subgroup being less chemo­ therapy-responsive with a less favourable course, and another being alkylator-­sensitive with longer survival overall. Of note, sub- groups of patients with as yet molecularly ­undefined tumours in the cohort with 1p19q-intact tumours also seemed to benefit from combination therapy. Although these observations are largely exploratory and stem from clinical trials that were insufficiently powered for such sub- group analyses, the similarities in outcome in two independent trials are remarkable. Even before prospective validation, the rel- evance of these results to patients has been deemed sufficient to prompt changes both in clinical practice and in the current trans- atlantic clinical trial portfolio. Radiotherapy alone should no longer be considered the standard of care in patients with 1p19q-­ codeleted anaplastic oligodendroglial tumours. The design of the ongoing CODEL trial (NCT00887146), which originally set out to compare the effects of radiotherapy alone, TMZ/RT→TMZ, and TMZ alone in patients with 1p19q-codeleted anaplastic glioma, has also been modified in light of the new data. The revised CODEL trial will compare radio­therapy plus PCV with TMZ/ RT→TMZ or TMZ alone. Long-term follow- up data from NOA‑04, the third relevant anaplastic glioma trial, which is compar- ing radiotherapy alone with chemotherapy (TMZ or PCV) alone,6 may soon indicate whether the hope for improved long-term control by alkylating agent chemotherapy alone is justified, and should help to validate 1p19q codeletion as a predictive biomarker. Trials in anaplastic glioma are increas- ingly challenging because of the demanding logistics and funding required for molecu- lar profiling and long-term follow-up, and new insights from molecular studies require continual reconsideration of our clinical research strategies. We propose that for clinical trials at least, the distinction between IDH1/2-mutant and IDH1/2-wild- type tumours should override the distinc- tion between WHO grade II, III and IV tumours, and provide guidance for clinical practice (Figure 1).7 Another major debate in neuro-oncology in 2013 focused on the clinical impact of the AVAglio and RTOG 0825 trials, which explored the efficacy of bevacizumab—a monoclonal antibody targeting vascular endothelial growth factor (VEGF)—in the treatment of newly diagnosed glioblas- toma.8,9 Efficacy outcomes were similar between the two trials: progression-free survival was prolonged by 3–4 months, but overall survival did not improve. Owing to differences in statistical design, the gain in progression-free survival reached stat­ istical significance in AVAglio, but not in RTOG 0825. No particular subgroups, as defined by age, extent of resection or MGMT promoter methylation status, derived pref- erential benefits from bevacizumab. In addition, a molecular signature predicting beneficial versus detrimental effects of beva- cizumab on overall survival, as proposed by RTOG, requires validation. Safety and tolerability data were compar­ able between the two trials, but observa- tions on cognitive function and quality of life were contradictory. AVAglio reported decreased steroid use and preserved quality of life with bevacizumab until progression, whereas RTOG 0825 reported decline in various domains of cognition and quality of life in bevacizumab-treated patients before progression. The test batteries were similar, but the time points differed, and testing was enforced by the protocol to a greater extent in AVAglio than in RTOG 0825. Central review of neuro­imaging in AVAglio seemed to rule out diffuse, nonenhancing disease progression as an explanation for early cognitive decline in bevacizumab-treated patients. While the exploratory analysis of the—albeit uncontrolled—BRAIN trial of single-agent bevacizumab in recur- rent glioblastoma revealed improvement in health-related quality of life and cogni- tive function,10 the possibility of adverse interactions between bevacizumab and ­radiotherapy remains. Owing to the lack of a survival gain, and the possibility of adverse effects on cogni- tive function and quality of life, the use of bevacizumab in newly diagnosed glioblas- toma may be most attractive in patients WHO grade (II)/III/IV glioma IDH1/2 Wild type WHO grade IV WHO grade II/III Mutant WHO grade II/III/(IV) Age ≤65 yearsAge >65 years MGMT− MGMT+ RT RT RT RT/PCV TMZ TMZ TMZ TMZ/RT TMZ TMZ/RT TMZ TMZ/RT TMZ TMZ or PCVPCV 1p19q intact 1p19q codeleted Histology Biomarker Therapy Or clinical trial in the respective pathomolecular subgroup MGMT− MGMT+ Figure 1 | An IDH-driven approach to diffuse and malignant gliomas. Abbreviations: IDH, isocitrate dehydrogenase; MGMT, O6 -methylguanine-DNA methyltransferase; MGMT+, hypermethylation of the MGMT promoter; MGMT–, no hypermethylation of the MGMT promoter; PCV, procarbazine, lomustine and vincristine; RT, radiotherapy; TMZ, temozolomide. Key advances ■■ 1p19q testing should be done for all patients with oligodendroglial tumours4,5 ■■ Anaplastic oligodendroglial tumours with 1p19q codeletions should be treated not with radiotherapy alone, but with alkylating agent chemotherapy, plus or minus radiotherapy4,5 ■■ The introduction of molecular markers into the next WHO Classification of Tumours of the Nervous System is inevitable ■■ Bevacizumab prolongs progression-free survival but not overall survival in newly diagnosed glioblastoma8,9 ■■ Current controversies on clinical benefit versus safety and toxicity of bevacizumab require further well-designed, prospective clinical trials © 2014 Macmillan Publishers Limited. All rights reserved
  • 71. KEY ADVANCES IN MEDICINE JANUARY 2014  |  63 NEUROLOGY with a low chance of benefiting from standard radiochemo­therapy; that is, those who have large tumours lacking MGMT promoter methylation, and are unlikely to receive salvage therapies at progression. These subgroups of patients were under- represented in AVAglio and RTOG 0825, and probably include a large proportion of the increasing population of elderly patients with glioblastoma. Controlled trials such as EORTC 26101 (NCT01290939) are required to define the role of bevacizumab in ­recurrent glioblastoma. Biomarkers to predict primary resist- ance to VEGF inhibition and to identify the biochemical escape pathways from such treatments are urgently needed to better define the role—if any—of VEGF inhibitors in glioma treatment. Following the failure of three rival anti-angiogenic agents, enzastaurin, cediranib and cilen- gitide, in glioblastoma, we cannot yet con- clude whether AVAglio and RTOG 0825 herald the end of, or a new beginning for, the era of anti-­angiogenic therapy for ­malignant glioma. The neuro-oncology field is making great progress in improving the molecu- lar subclassification of gliomas, and the first molecular biomarkers for clinical ­decision-­making are entering clinical prac- tice. In 2013, individualized cancer care has become a reality for many patients with brain tumours. The main challenges for patients with anaplastic gliomas will be the implementation of molecular testing in day-to-day practice, improvement of outcome in the poor-prognosis group, and development of new surrogate end points for earlier assessment of success in patients with progression-free survival of many years. For anti-angiogenic treatments, the best ­position—first-line or recurrence— for anti-VEGF treatment remains to be defined, as do the molecularly defined subgroups who are most likely to benefit from this treatment. More importantly, anti-­angiogenic agents acting beyond the VEGF–VEGF receptor pathway, and com- binations that also aim to kill tumour cells, await development. Department of Neurology and Brain Tumour Centre, University Hospital Zurich, Frauenklinikstrasse 26, 8091 Zurich, Switzerland (M. Weller). Department of Neurooncology, Neurology Clinic & National Centre for Tumour Diseases, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany (W. Wick). Correspondence to: M.Weller michael.weller@usz.ch Competing interests M. Weller declares associations with the following companies: Isarna Therapeutics, Bayer, MagForce, Merck Serono, MSD, Roche. W. Wick declares associations with the following companies: Apogenix, Boehringer Ingelheim, Eli Lilly, MagForce, MSD, Roche. See the article online for full details of the relationships. 1. Weller, M. et al. Molecular neuro-oncology in clinical practice: a new horizon. Lancet Oncol. 14, e370–e379 (2013). 2. Sturm, D. et al. Hotspot mutations in H3F3A and IDH1 define distinct epigenetic and biological subgroups of glioblastoma. Cancer Cell 22, 425–437 (2012). 3. Brennan, C. W. et al. The somatic genomic landscape of glioblastoma. Cell 155, 462–467 (2013). 4. Van den Bent, M. et al. Adjuvant procarbazine, lomustine, and vincristine chemotherapy in newly diagnosed anaplastic oligodendroglioma: long-term follow-up of EORTC Brain Tumor Group Study 26951. J. Clin. Oncol. 31, 344–350 (2013). 5. Cairncross, G. et al. Phase III trial of chemoradiotherapy for anaplastic oligodendroglioma: long-term results of RTOG 9402. J. Clin. Oncol. 31, 337–343 (2013). 6. Wick, W. et al. NOA‑04 randomized phase III trial of sequential radiochemotherapy of anaplastic glioma with procarbazine, lomustine, and vincristine or temozolomide. J. Clin. Oncol. 27, 5874–5880 (2009). 7. Wick, W. et al. Prognostic or predictive value of MGMT promoter methylation in gliomas depends on IDH1 mutation. Neurology 81, 1515–1522 (2013). 8. Chinot, O. et al. Bevacizumab plus radiotherapy/ temozolomide for newly diagnosed glioblastoma. N. Engl. J. Med. (in press). 9. Gilbert, M. R. et al. Phase III double-blind placebo-controlled trial evaluating bevacizumab (Bev) in patients (Pts) with newly diagnosed glioblastoma (GBM). N. Engl. J. Med. (in press). 10. Wefel, J. S. et al. Neurocognitive function in patients with recurrent glioblastoma treated with bevacizumab. Neuro Oncol. 13, 660–668 (2011). DEMENTIA IN 2013 Frontotemporal lobar degeneration —building on breakthroughs Julie van der Zee and Christine Van Broeckhoven Genetic research in frontotemporal lobar degeneration (FTLD) is gaining momentum. Following the discovery of a repeat expansion in the gene C9 open reading frame 72 (C9orf72), three major genes and associated disease mechanisms and inclusion body pathologies have emerged, paving the way for personalized medicine in FTLD. van der Zee, J. & Van Broeckhoven, C. Nat. Rev. Neurol. 10, 70–72 (2014); published online 7 January 2014; doi:10.1038/nrneurol.2013.270 In less than a decade, immense progress has been made in unravelling the disease mech- anisms of frontotemporal lobar degener­ ation (FTLD). The discovery 2 years ago of a repeat expansion in the gene C9 open reading frame 72 (C9orf72)1–3 represented a major leap forward in our understanding of FTLD, setting the stage in 2013 for the dis- covery of a new mutation ­mechanism and a new inclusion body pathology. Testing of patient cohorts worldwide has established the C9orf72 repeat expan- sion as the major genetic cause of FTLD, amyotrophic lateral sclerosis (ALS), and the combined syndrome of both diseases (FTLD–ALS), reaching mutation frequen- cies of up to 29%, 50% and 88%, respec- tively.4,5 In addition to establishing C9orf72 mutation frequency in disease subtypes, work in 2013 began to elucidate the disease mechanisms of the mutation. The GGGGCC repeat expansion is located in intron 1 fol- lowing the noncoding exon 1, or in the regulatory region of the C9orf72 gene. Recent studies have shown that the number of repeat units in patients can range up to ­thousands of copies,6 whereas unaffected control individuals harbour two to 24 repeat units.3,5 Interestingly, repeats ranging from seven to 24 units have been suggested to pre- dispose to disease: in vitro studies demon- strated an inverse correlation between repeat size and gene expression starting at just nine units compared with the most common two-unit allele, with up to 50% reduction in ­expression for 24-unit alleles.5 Mutations in the granulin (GRN) gene or microtubule-associated protein tau © 2014 Macmillan Publishers Limited. All rights reserved
  • 72. 64  |  JANUARY 2014 www.nature.com/reviews NEUROLOGY (MAPT) gene are known to be associated with FTLD. The identification of C9orf72 as a third major gene implicated in FTLD led Van Langenhove and colleagues to perform genotype–phenotype correlation studies in cohorts harbouring mutations in each of the genes, and to design revised guide- lines for molecular diagnostic testing.7 Of the three genes, only C9orf72 is associated with both FTLD and ALS. Whereas carriers of GRN and MAPT mutations never present with ALS symptoms, 30% of patients with C9orf72-associated FTLD develop con- current ALS. Importantly, in the group of patients with FTLD–ALS, C9orf72 accounts for up to 88% of patients with familial disease.3 Equally noteworthy, however, is the fact that over 70% of patients with C9orf72- associated FTLD will not develop symp- toms of ALS or other types of motor neuron disease. In the majority of patients with mutated C9orf72, the dementia phenotype is consistent with the behavioural variant of frontotemporal dementia (bvFTD). The other FTLD mutations are also most fre- quently associated with this form of FTLD, but the bvFTD associated with C9orf72 mutations typically presents as inappropri- ate behaviour and agitation, in contrast to bvFTD associated with GRN mutations, where apathy dominates the clinical picture. Variability in age of disease onset and disease duration between and within fami- lies is a recurrent observation in all three major FTLD subtypes, pointing towards genetic or epigenetic modifiers that influ- ence the clinical manifestation of these causal mutations. In the group of C9orf72 carriers, about 50% were affected by age 60 years, with penetrance reaching 90% by 70 years, although some carriers lived up to 75 years without developing apparent clinical signs of disease. In terms of disease duration, development of ALS was a strong negative prognostic factor, with reduced survival to less than 2 years after the first signs of ALS developed. Overall, the core clinical features of C9orf72-related FTLD were found to be disease onset before age 65 years, a positive family history, predomi- nance of bvFTD, and co-incidence with ALS. Remarkably, in a Belgian FTLD cohort, up to nine in 10 patients fitting these criteria were carriers of a C9orf72 expansion.7 Clinical differentiation at the individual patient level remains challenging, but these obser- vations can be translated into a prioritization scheme for gene testing in the framework of medical genetic diagnostics. In patients with FTLD–ALS, testing for C9orf72 repeat expansions should be performed first. C9orf72 is also the most frequent cause of bvFTD without ALS, particularly in patients who present with disinhibition. In contrast to the subtle differences in clinical presentation between C9orf72- related and other subtypes of FTLD, C9orf72-related pathology shows some unique, distinctive characteristics. In addi- tion to the TAR DNA-binding protein 43 (TDP‑43) pathology, patients show abun- dant TDP‑43-negative, p62-positive dot-like and star-shaped inclusions, predominantly in the cerebellum, hippo­campus and fronto­temporal cortex. In 2013, Mori and colleagues went on to further characterize these inclusions, and hypothesized that they may consist of aggregation-prone di­peptide repeat (DPR) proteins resulting from bidirec­tional translation from the noncoding GGGGCC repeat.8 Such bidirectional repeat translation had been described in another repeat expansion disease—spinocerebellar ataxia type 8 (SCA 8)—with a noncoding CAG repeat located in the gene ATXN8, through a mechanism of non-ATG-initiated translation, termed RAN translation. Using antibodies specific to the expected sense and antisense DPRs, the researchers dem- onstrated that in the absence of an ATG start codon, the GGGGCC expansion is indeed bidirectionally translated into five distinct DPR proteins.8 In-depth analysis of the neuro-­ anatomical distribution of the DPR and TDP‑43 pathology showed high DPR load in the cerebellum, all neocortical regions and hippocampus, as well as some inclu- sions in motor neurons.9 Importantly, DPR-positive cytoplasmic and intra­ nuclear neur­onal inclusions showed complete overlap with TDP‑43-negative, p62-­positive ­inclusions—in both shape and abundance—and were specific to patients with FTLD–ALS who harbour a C9orf72 repeat expansion. Finally, observation of Gene Mutation mechanism Pathology MAPT Gain of function Accumulation of defective tau GRN Loss of function Loss of GRN secretion C9orf72 Repeat expansion RAN translation DPR accumulation Tau TDP-43 GA × Figure 1 | Three subtypes of frontotemporal lobar degeneration. Mutations in three major genes —associated with three distinct disease mechanisms and pathologies—have been identified to cause frontotemporal lobar degeneration. Abbreviations: C9orf72, C9 open reading frame 72; DPR, dipeptide repeat protein; GA, poly-GA DPR; GRN, granulin; MAPT, microtubule-associated protein tau; TDP‑43, TAR DNA-binding protein 43. Key advances ■■ Genotype–phenotype correlation studies in C9 open reading frame 72 (C9orf72)-related frontotemporal lobar degeneration (FTLD) enabled formulation of revised guidelines for genetic diagnostic testing7 ■■ Dipeptide repeat (DPR) aggregation owing to bidirectional RAN translation of the GGGGCC repeat is the key pathological feature of C9orf72-related FTLD8 ■■ DPR-positive cytoplasmic and intranuclear neuronal inclusions show complete overlap with TAR DNA-binding protein 43 (TDP-43)-negative, p62-positive inclusions and are specific to C9orf72-related FTLD and amyotrophic lateral sclerosis9 ■■ Pathological findings suggest that RAN translation and DPR aggregation are early events in FTLD that precede and potentially trigger TDP-43 accumulation5,9 ■■ FTLD is a heterogeneous neurodegenerative brain disease—with three major genes, disease mechanisms and neuropathologies—underscoring the need for personalized medicine tailored to the patient’s molecular signature © 2014 Macmillan Publishers Limited. All rights reserved
  • 73. KEY ADVANCES IN MEDICINE JANUARY 2014  |  65 NEUROLOGY DPR pathology in a rare, TDP‑43-negative Belgian carrier of a C9orf72 repeat expan- sion5 and aggregates composed of a DPR core surrounded by TDP‑43 suggested that RAN translation and DPR aggregation are early pathological events that precede and potentially trigger TDP‑43 accumulation.8,9 As such, Mori and colleagues demon- strated that DPR inclusion pathology is a direct consequence of the C9orf72 repeat expansion and that DPR aggregation due to RAN translation is the key pathologi- cal feature of C9orf72-related FTLD and ALS. Subsequently, they proposed that the current pathological classification and nomenclature should be revised in these patients to FTLD-DPR. In addition to DPR accumulation and TDP‑43 pathology, previ- ously proposed disease mechanisms proba- bly also contribute, in part, to disease. These mechanisms include haplo­insufficiency through loss of gene expression3–5 and RNA toxicity caused by sequestration of RNA- binding proteins.1,10 An important next step will be to be determine the individual contribution of these four mechanisms to disease, and to characterize the early and late pathological events and how they ­contribute to the phenotype. Over the years, it has become increas- ingly clear that FTLD represents one of the most heterogeneous neurodegenera- tive brain diseases, with three major genes, disease mechanisms and neuropathologies complicating patient diagnosis, care and treatment (Figure 1). This hetero­geneity has direct implications for translational research and therapy development, and sug- gests the potential for personalized medicine on the basis of the molecular signature of the FTLD subtype. Neurodegenerative Brain Diseases Group, Department of Molecular Genetics,VIB and Laboratory of Neurogenetics, Institute Born- Bunge, University of Antwerp, Universiteitsplein 1, B‑2610 Antwerp, Belgium (J. van der Zee, C. Van Broeckhoven). Correspondence to: C.Van Broeckhoven christine.vanbroeckhoven@molgen.vib-ua.be Acknowledgements The authors thank J.-J. Martin and A. Sieben for the immunohistochemistry images and expert support. The authors receive funding from the Belgian Science Policy Office Interuniversity Attraction Poles programme, the European Centers of Excellence in Neurodegeneration, the Methusalem Excellence programme, the Alzheimer Research Foundation, the Medical Foundation Queen Elisabeth, the Research Foundation Flanders, the Agency for Innovation by Science and Technology Flanders, the University of Antwerp Research Fund, and the MetLife Foundation Award for Medical Research. Competing interests The authors declare no competing interests. 1. DeJesus-Hernandez, M. et al. Expanded GGGGCC hexanucleotide repeat in noncoding region of C9ORF72 causes chromosome 9p-linked FTD and ALS. Neuron 72, 245–256 (2011). 2. Renton, A. E. et al. A hexanucleotide repeat expansion in C9ORF72 is the cause of chromosome 9p21-linked ALS-FTD. Neuron 72, 257–268 (2011). 3. Gijselinck, I. et al. A C9orf72 promoter repeat expansion in a Flanders-Belgian cohort with disorders of the frontotemporal lobar degeneration-amyotrophic lateral sclerosis spectrum: a gene identification study. Lancet 11, 54–65 (2012). 4. Cruts, M., Gijselinck, I., Van Langenhove, T., van der Zee, J. & Van Broeckhoven, C. Current insights into the C9orf72 repeat expansion diseases of the FTLD/ALS spectrum. Trends Neurosci. 36, 450–499 (2013). 5. van der Zee, J. et al. A pan-European study of the C9orf72 repeat associated with FTLD: geographic prevalence, genomic instability, and intermediate repeats. Hum. Mutat. 34, 363–373 (2013). 6. Dols-Icardo, O. et al. Characterization of the repeat expansion size in C9orf72 in amyotrophic lateral sclerosis and frontotemporal dementia. Hum. Mol. Genet. http://dx.doi.org/10.1093/hmg/ddt460. 7. Van Langenhove, T. et al. Distinct clinical characteristics of C9orf72 expansion carriers compared with GRN, MAPT, and nonmutation carriers in a Flanders-Belgian FTLD cohort. JAMA Neurol. 70, 365–373 (2013). 8. Mori, K. et al. The C9orf72 GGGGCC repeat is translated into aggregating dipeptide-repeat proteins in FTLD/ALS. Science 339, 1335–1338 (2013). 9. Mackenzie, I. R. et al. Dipeptide repeat protein pathology in C9ORF72 mutation cases: clinico- pathological correlations. Acta Neuropathol. 126, 859–879 (2013). 10. Lagier-Tourenne, C. et al. Targeted degradation of sense and antisense C9orf72 RNA foci as therapy for ALS and frontotemporal degeneration. Proc. Natl Acad. Sci. USA 110, E4530–E4539 (2013). MULTIPLE SCLEROSIS IN 2013 Novel triggers, treatment targets and brain atrophy measures Xavier Montalban and Mar Tintoré 2013 witnessed advances in many aspects of multiple sclerosis (MS) research. Two studies highlighted a potential role for salt as an MS trigger, and one immunomodulatory drug performed well in clinical trials. Moreover, treatment effects of MS drugs were shown to correlate inversely with brain atrophy and disease progression. Montalban, X. & Tintoré, M. Nat. Rev. Neurol. 10, 72–73 (2014); published online 7 January 2014; doi:10.1038/nrneurol.2013.274 The year 2013 came to a close with improved understanding of how well-known environ­ mental factors associated with multiple sclero­sis (MS) contribute to the develop- ment of this disease. In addition, treatment advances have widened the scope to tackle brain atrophy and disease ­progression in patients with MS. The past 50 years have witnessed a marked increase in the incidence of auto- immune diseases, which has probably been driven by changes in environmental factors. Epidemiological risk factors for MS include vitamin D deficiency, exposure to Epstein–Barr virus in early childhood, and cig­arette smoking. Recent studies have shown that components of the daily diet and gut microbiota can strongly affect the levels of effector T cells in the gut; one such dietary factor could well be salt. In 2013, two indepen­dent groups came to the conclusion that increased sodium chloride concentra- tions can promote autoimmune diseases by stimulating induction of IL‑17-producing helper T (TH 17) cells from CD4+ T cells. Wu et al. showed that increased salt concentra- tions in vitro or in mice (via a high-salt diet) induced expression of serum glucocorticoid kinase 1 (SGK1) in T cells and enhanced RossEverhard|Dreamstime.com © 2014 Macmillan Publishers Limited. All rights reserved
  • 74. 66  |  JANUARY 2014 www.nature.com/reviews NEUROLOGY TH 17 differentiation.1 Kleinewietfeld et al. found that modest increases in sodium chloride concentration could stimulate a nearly logarithmic induction of IL‑17 in naive CD4+ cells in vitro that was mediated through p38/MAPK, NFAT5 and SGK1.2 In agreement with these findings, addition of salt to the diet of mice with experimental autoimmune encephalomyelitis—the main animal model of MS—led to severe symptom worsening and increased numbers of TH 17 cells.2 These two studies suggest that high salt intake could trigger tissue inflamma- tion and autoimmune disease. Whether salt intake is causally related to development of auto­immune disease in humans, however, is yet to be proved. Smoking has long been linked with increased risk of developing MS, but studies on its potential influence on the clinical course of the disease have yielded conflict- ing results. A possible association between smoking and disease progression in MS is of particular interest given the reported nega- tive correlation between smoking and the risk of some neuro­degenerative conditions such as Parkinson disease.3 Manouchehrinia et al.4 analysed data from 895 patients with MS, about half of whom were regular smokers at the time of disease onset or diag- nosis. The results suggested regular smoking is associated with more-severe disease and faster disability progression. In addition, smoking cessation—whether before or after MS onset—was associated with a slower progression of disability.3 Notwithstanding the retrospective nature of this study, meas- ures to prevent and reduce smoking in MS are warranted. Targeted immunotherapy to provide treatment benefits while avoiding adverse immuno­modulatory effects remains an elusive goal in the management of auto- immune diseases. Previous studies in patients with relapsing–remitting forms of MS (RRMS) suggest that daclizumab— a monoclonal antibody that binds CD25, the α‑subunit of the T‑cell IL‑2 receptor (IL2RA)—used in combination with IFN‑β was well tolerated and reduced disease activ- ity in patients who were refractory to IFN‑β alone.5 In 2013, Gold et al. conducted a ran- domized, double-blind, placebo-controlled, phase III trial of daclizumab high-yield process (HYP) in patients with RRMS.6 The HYP form of the drug has the same amino acid sequence as previous versions but differs in its glycosylation profile, result- ing in decreased antibody-dependent cel- lular cytotoxicity. Patients were randomly assigned to receive subcutaneous injections of daclizumab HYP or placebo, every 4 weeks for 52 weeks. Daclizumab HYP treatment was associated with a significantly reduced annual­ized relapse rate and disability pro- gression compared with placebo.6 A genome- wide association scan for MS risk genes and candidate gene association studies previously highlighted the locus encompassing IL2RA, making this treatment especially relevant to MS.7 Interestingly, circulating levels of CD56bright natural killer cells increased in patients treated with daclizumab HYP versus placebo, suggesting that CD56bright natural killer cells might mediate the therapeutic effects of daclizumab HYP in MS, although this suggestion has yet to be confirmed. In most individuals with MS, the disease evolves from a relapsing to a progressive form and, in about 15% of cases, MS presents as purely progressive. A neuro­degenerative process is thought to underlie progressive MS. Neurodegeneration begins early in MS and contributes to accumulation of irrevers- ible disability. Measurements of percentage brain volume changes and brain paren­ chymal fraction over time are among the most well-studied methods for quantifying neurodegeneration in MS. Brain atrophy measures correlate with neuro­logical and neuro­psychological disability and are fea- sible outcome measures in large-scale ­multicentre studies. Recently, Sormani et al. performed a meta- analysis to assess the relationship between the size of a treatment effect on brain atrophy and disability progression.8 The investigators reviewed all randomized trials that evaluated the effects of disease-modifying drugs on both brain atrophy and disability progression in RRMS. Finally, 13 trials involving around 13,500 patients were included in the analysis. Treatment effects on disability progression correlated significantly with treatment effects on brain atrophy and active MRI lesions. Inclusion of treatment effects on both MRI end points in a multi­variate model strength- ened the correlation, and both variables were indepen­dently related to treatment effect on disability progression. This study shows that treatment effects on brain atrophy and MRI measures can be used as a surrogate outcome for treatment effects on clinical outcome, and might form useful end points in future trials of disease-modifying ­therapies for MS. In summary, research in 2013 improved our ability to understand, treat and prevent disease progression in MS. The outlook for MS—an area now in front-line research— continues to improve. Reducing disease progression and neuroprotection are becom- ing realistic goals to be expected for the next decade. Department of Neurology/Neuroimmunology, Centre d’Esclerosi Múltiple de Catalunya (Cemcat), Hospital Universitari Vall d’Hebron, Edifici Cemcat, Passeig de la Vall d’Hebron 119‑129, 08035 Barcelona, Spain (X. Montalban, M. Tintoré). Correspondence to: X. Montalban xavier.montalban@cem-cat.org Competing interests X. Montalban declares associations with the following companies: Almirall, Bayer, Biogen Idec, GeNeuro, Genzyme, Merck, Novartis, Roche, Sanofi, Teva. M. Tintoré declares associations with the following companies: Bayer, Biogen Idec, Genzyme, Merck, Novartis, Teva. See the article online for full details of the relationships. 1. Wu, C. et al. Induction of pathogenic TH 17 cells by inducible salt-sensing kinase SGK1. Nature 496, 513–517 (2013). 2. Kleinewietfeld, M. et al. Sodium chloride drives autoimmune disease by the induction of pathogenic TH 17 cells. Nature 496, 518–522 (2013). 3. Nicoletti, A. et al. Voluptuary habits and clinical subtypes of Parkinson’s disease: the FRAGAMP case control study. Mov. Disord. 25, 2387–2394 (2010). 4. Manouchehrinia, A. et al. Tobacco smoking and disability progression in multiple sclerosis: United Kingdom cohort study. Brain 136, 2298–2304 (2013). 5. Wynn, D. et al. Daclizumab in active relapsing multiple sclerosis (CHOICE study): a phase 2, randomised, double-blind, placebo-controlled, add-on trial with interferon beta. Lancet Neurol. 9, 381–390 (2010). 6. Gold, R. et al. Daclizumab high-yield process in relapsing–remitting multiple sclerosis (SELECT): a randomised, double-blind, placebo-controlled trial. Lancet 381, 2167–2175 (2013). 7. International Multiple Sclerosis Genetics Consortium & The Wellcome Trust Case Control Consortium 2. Genetic risk and a primary role for cell-mediated immune mechanisms in multiple sclerosis. Nature 476, 214–219 (2011). 8. Sormani, M. P., Arnold, D. L. & De Stefano, N. Treatment effect on brain atrophy correlates with treatment effect on disability in multiple sclerosis. Ann. Neurol. http://dx.doi.org/ 10.1002/ana.24018. Key advances ■■ Increased sodium chloride concentrations can promote autoimmune diseases1,2 ■■ Regular smoking is associated with more-severe disease and faster disability progression in multiple sclerosis (MS); smoking cessation is associated with slower disability progression4 ■■ Daclizumab—a monoclonal antibody— was well tolerated and reduced disease activity in relapsing MS6 ■■ Brain atrophy measures are feasible measures for treatment effects in drug trials for MS8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 75. 100 years of Lewy pathology Michel Goedert, Maria Grazia Spillantini, Kelly Del Tredici and Heiko Braak In 1912, Fritz Heinrich Lewy identified the intracellular inclusions that are characteristic of Parkinson disease (PD). Goedert et al. present an overview of Lewy’s life, and discuss the central role of Lewy pathology in PD and other neurodegenerative disorders. doi:10.1038/nrneurol.2012.242 Deciphering the mechanism underlying late-onset Alzheimer disease Dimitrije Krstic and Irene Knuesel Drug development efforts for late-onset Alzheimer disease (AD) have met with disappointing results. Krstic and Knuesel argue for a re- evaluation of pathological mechanisms underlying the disease, with a shift of focus away from amyloid-β as the key therapeutic target. doi:10.1038/nrneurol.2012.236 Apolipoprotein E and Alzheimer disease: risk, mechanisms and therapy Chia-Chen Liu, Takahisa Kanekiyo, Huaxi Xu and Guojun Bu The ε4 allele of the apolipoprotein E (APOE) gene is the strongest genetic risk factor for Alzheimer disease. Bu and colleagues describe the pathogenic links between Apo-E4 and neurodegeneration, and suggest therapeutic strategies to target Apo-E. doi:10.1038/nrneurol.2012.263 Cerebrospinal fluid biomarkers in Parkinson disease Lucilla Parnetti, Anna Castrioto, Davide Chiasserini, Emanuele Persichetti, Nicola Tambasco, Omar El-Agnaf and Paolo Calabresi Parkinson disease (PD) has a long preclinical phase, which presents both a diagnostic challenge and an opportunity for early intervention. Parnetti et al. discuss evidence to support the utility of cerebrospinal fluid levels of various proteins as biomarkers for PD diagnosis. doi:10.1038/nrneurol.2013.10 Biomarkers of mild traumatic brain injury in cerebrospinal fluid and blood Henrik Zetterberg, Douglas H. Smith and Kaj Blennow Mild traumatic brain injury (TBI) is head trauma resulting in brief loss of consciousness and/or alteration of mental state. Methods to determine the extent of brain injury and potential long-term damage are lacking. Here, the authors discuss the need for fluid biomarkers of mild TBI. doi:10.1038/nrneurol.2013.9 The clinical maze of mitochondrial neurology Salvatore DiMauro, Eric A. Schon, Valerio Carelli and Michio Hirano Mitochondrial diseases are a complex and clinically heterogeneous group of disorders. DiMauro et al. review current knowledge of defects of the mitochondrial respiratory complex that lead to neurological mitochondrial disorders. doi:10.1038/nrneurol.2013.126 Treatment trials in progressive MS—current challenges and future directions Marcus W. Koch, Gary Cutter, Peter K. Stys, V. Wee Yong and Luanne M. Metz Most patients with multiple sclerosis (MS) will at some point experience the progressive form of the disease. Koch et al. describe current limitations of trials in progressive MS, and present approaches to address these challenges. doi:10.1038/nrneurol.2013.148 The epidemiology of ALS: a conspiracy of genes, environment and time Ammar Al-Chalabi and Orla Hardiman Considerable progress has been made in elucidating the genetic causes of amyotrophic lateral sclerosis (ALS), but the contribution of environmental factors has been more difficult to determine. Al-Chalabi and Hardiman outline the current state of knowledge regarding the environmental and genetic epidemiology of ALS. doi:10.1038/nrneurol.2013.203 The emerging roles of microRNAs in CNS injuries Oneil G. Bhalala, Maya Srikanth and John A. Kessler MicroRNAs (miRNAs) are key regulators of molecular and cellular responses in development, health and disease. Bhalala et al. discuss findings from miRNA microarray studies in stroke, traumatic brain injury and spinal cord injury. doi:10.1038/nrneurol.2013.67 Controversies in defining and determining death in critical care James L. Bernat Since the development of life support technology, the definition of death has been challenging. Bernat outlines the brain criteria and the circulatory–respiratory criteria of death, and discusses controversial issues surrounding these definitions. doi:10.1038/nrneurol.2013.12 Editors’ picks of the year February 2014 volume 10 no. 2 www.nature.com/reviews AUTISM SPECTRUM DISORDER Reviewing the latest advances in genetics and neuroimaging Disorders of consciousness after acquired brain injury What is the state of the science? NEUROLOGY nrneurol_OFC_FEB14.indd 1 24/01/2014 11:51 * * * * * * * * * * A selection of articles published during 2013 in Nature Reviews Neurology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Neurology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 76. RHEUMATOLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  67 GOUT IN 2013 Imaging, genetics and therapy: gout research continues apace Fiona M. McQueen In 2013, much progress has occurred in gout research. Imaging continues to help elucidate aspects of pathophysiology and now suggests that healing of erosions could occur when urate levels are reduced dramatically. New genetic loci associated with hyperuricaemia have been identified and management strategies for prophylaxis of gout flares continue to evolve. McQueen, F. M. Nat. Rev. Rheumatol. 10, 67–69 (2014); published online 26 November 2013; doi:10.1038/nrrheum.2013.164 During2013,therehavebeenmajoradvances in gout research. The pathological basis of this disease and response to therapy continue to be investigated using imaging (Figure 1). Explor­atory data indicate that gouty erosions have the potential to heal in patients treated with intensive urate-lowering therapy (ULT), leading to tophus regression. This finding provides a rationale for aiming for a very low serum uric acid (SUA) level in situations in which the skeleton shows evidence of erosive change. The genetics of hyperuricaemia have recently been highlighted because of a genome-wide association study (GWAS) that identified multiple new loci of interest, some of which implicate glucose metabolism in systemic urate control—further linking gout with other features of the metabolic syn- drome. Advances in management include a focus on prevention of the acute gout flare during initiation of ULT, an important topic considering the plethora of new drugs being developed and the negative effects that flares might have on long-term patient compliance. Imaging continues to yield informa­tion rele­vant to gout pathology and holds pro­ mise for monitoring responses to ULT.1 Peg­ loticase is an enzymatic form of ULT tar­geted to patients with chronic refrac­tory gout,2 and provides a unique in vivo model for examining the effects of profound urate lower­ing on the gouty joint. This issue was recently explored by Dalbeth et al.1 in a US–New Zealand collaboration. Serial radio­graphs (hands and feet) were obtained from eight patients with chronic tophaceous gout treated with pegloticase to determine whether intraosseous tophus resolution might allow bone erosions to regress after 12 months. As expected, urate levels were decreased in all patients. Interest­ingly, there was indeed a change in the radiographic erosion score over this period (by 7 units; P = 0.008), but joint-space narrowing (JSN) scores did not change. Further reductions were observed in erosion (but not JSN) scores for the five patients who were analysed again by radiograph­y after 24 months. These findings are consistent with the direct link between tophus deposition and erosion in gout.3 Using ULT to cause dissolution of an intraosseous tophus could potentially lead to a large bony defect that might collapse owing to loss of structural integrity. However, both sclerosis and ‘filling in’ of erosions were observed, indicating ini- tiation of repair. By contrast, radiographic JSN, a surrogate measure of cartilage dam­ age, was unchanged after pegloticase. Car­ tilage has recently been in the imaging spotlight with the description of an ultra- sonographic “double contour sign”, thought Synovitis: on PDUS Cartilage: coated by MSU crystals (ultrasonography) Synovitis and tenosynovitis: on MRI Imaging in gout reveals pathology Bone erosions: Tophi sited within gouty erosions on CT, DECT and ultrasonography Tophaceous deposits: within joints, tendons and entheses (DECT) a c e fd b g Figure 1 | Different imaging modalities reveal all aspects of gout pathology. a | High-resolution CT scan (wrist, axial): large gout erosion plus tophus at 1st metacarpal base (circle). b | DECT (great toe): tophus (red) within erosions (arrows). c | Ultrasonography (1st MTP joint): erosions (arrows). d | DECT (3D reconstruction): tophaceous deposits at MTP joints (circle), Achilles tendon sheath and plantar fascia (arrows). e | Ultrasonography (1st metatarsal head): double contour sign (arrows). f | MRI (wrist; post-contrast axial T1w scan): synovitis at distal radioulnar joint (arrow) and extensor tenosynovitis (arrowheads). g | PDUS (great toe): vascular signal indicating synovitis. Abbreviations: DECT, dual-energy CT; MTP, metatarsophalangeal; PDUS, power Doppler ultrasonography. © 2014 Macmillan Publishers Limited. All rights reserved
  • 77. S68 www.nature.com/nrrheum/collections/xxxx RHEUMATOLOGY 68  |  JANUARY 2014 www.nature.com/reviews to indicate deposition of monosodium urate (MSU) crystals in a fine layer over hyaline cartilage.4 Pegloticase would probably also lead to dissolution of this MSU crystal layer, so does this imply that reparative mecha- nisms for cartilage are less efficient than for bone, or that cartilage integrity was not much affected (by MSU)? Larger studies are clearly warranted, but the overall message from this work is positive—bone damage from tophus deposition in gout might be at least partially reversible. Thus, maintenance of low urate levels in patients with erosive gout, even when flares are no longer occurring, seems to be important. Contrasting with the very small patient numbers in the previous study, Kottgen et al.5 combined data from >140,000 individuals of European ancestry to identify genetic loci associated with SUA concentrations. Using powerful GWAS methods, 26 SUA- associated single nucleotide polymor­phisms (SNPs) were identified, 10 having been already described and 16 being new loci. A weighted genetic score was constructed on the basis of the number of risk alleles identi- fied across loci. Risk scores were associated with gout prevalence, which increased from <1% to 18% across risk score categories in different populations, and with gout inci- dence in other populations in which patients with gout were followed for up to 22 years. Although the renal urate transporter gene ABCG2 and the glucose transporter 9 gene (GLUT9, also known as SLC2A9), were con- firmed to be associated with SUA levels, none of the genes at the newly identified loci were involved in urate trans­port. The analysis highlighted links with the inhibins–­activins growth factor system and with glucose meta­ bolism genes, which is consistent with the association between hyper­uricaemia and the later development of type II dia­betes mellitus in men with high cardio­vascular risk.6 Therapeutic agents that promote hypo- glycaemia by lowering insulin resistance (such as metformin) tend also to decrease SUA levels, emphasizing the complex links within the metabolic syndrome.5 As part of the GWAS analysis, different ethnic groups were examined and although allele frequen- cies at the index SNPs varied across groups, associations were of comparable magnitude and in the same direction. Other studies have suggested that the strength of such associations can vary according to ethnicity; New Zealand Maori and Pacific is­landers with gout were shown to have the same risk variants in SLC2A9 as white indivi­ duals, but the degree of risk conferred was substantially greater in the former group.7 Des­pite these extensive new data,5 it is worth noting that the variance in SUA level explained by all associations was only 7.0% (5.2% being explained by pre­viously known loci), leaving a sizeable gap between current genetic knowledge and heritability estimates for SUA levels of 40–60%. The optimal use of novel and conventional ULT remains a crucial issue. In 2013, Mitha et al.8 reported results of the PRESURGE2 study, examining the efficacy of rilonacept for the prevention of gout flare during ULT initiation with allo­purinol. Most clinicians are familiar with the common occurrence of gout flare in these circumstances (which can contribute to patient noncompliance), there­fore, prevention of flare is an important goal. Rilonacept is a soluble decoy receptor fusion protein that binds IL-1α and IL-1β, preventing activation of cell surface recep- tors. As IL-1β is known to be a major inflam- matory cytokine in gout, a strong scientific rationale exists for this strategy, especially for patients who cannot tolerate other medica- tions used in this setting (NSAIDs and col- chicine).9 Gout flares have been proposed to occur when the SUA level is suddenly decreased, resulting in release of ‘naked’ MSU crystals from inside the tophus.10 This step initiates a cascade of events, triggering the innate immune response and leading to IL-1β release, neutro­phil activation and acute inflammation. Mitha et al.8 recruited 248 patients with gout who were treated with allopurinol 300 mg daily, titrated upwards to achieve a SUA of <6 mg/dl (~0.36 mmol/l). The participants were randomly assigned to receive weekly subcutaneous injections of placebo, or 80 mg or 160 mg rilonacept. Rilo­ nacept significantly reduced the occurrence of flares, with >70% of treated patients having none compared with 44% of those receiving placebo (P <0.0001). The number of adverse events was similar for all groups and injection site reactions to rilonacept were mild. Colchicine is currently considered the standard of care for flare prophylaxis during initiation of ULT.9 Colchicine and NSAIDs should generally be avoided in patients with chronic renal impairment, and inhibitors of IL-1β (rilonacept or canakinumab) might have an important niche role here. Unfor­ tunately, information about renal function is lacking in the Mitha et al.8 study and no large trials of IL-1β blockade in patients with renal impairment are available. Bene­ fits would need to be weighed against risks of potentiating infection, especially in those receiving haemodialysis, and the use of expensive biologic agents always raises pharmacoeconom­ic issues. In summary, 2013 has seen gout research proceeding apace on many fronts, ranging from imaging for monitoring the effects of ULT, to state-of-the-art genetics, to the further use of cytokine inhibitors. Moving forward, priori­ties for the research agenda include imaging studies using CT and dual- energy CT to further investigate the erosion response to ULT, genetics studies to investi- gate the ‘heritability gap’ referred to earlier and trials of therapeutics for patients with gout who have renal impairment. Department of Molecular Medicine and Pathology, University of Auckland, PO Box 92019,Auckland 1023, New Zealand. f.mcqueen@auckland.ac.nz Acknowledgements The author wishes to thank R. Stuart (Northern Clinic, Auckland), N. Dalbeth and A. Doyle (University of Auckland), and Q. Reeves (Auckland District Health Board) for their assistance in providing images for Figure 1. Competing interests The author declares no competing interests. 1. Dalbeth, N. et al. Exploratory study of radiographic change in patients with tophaceous gout treated with intensive urate- lowering therapy. Arthritis Care Res. http:// dx.doi.org/10.1002/acr.2205. 2. Becker, M. A. et al. Long-term safety of pegloticase in chronic gout refractory to conventional treatment. Ann. Rheum. Dis. 72, 1469–1474 (2013). 3. Dalbeth, N. et al. Mechanisms of bone erosion in gout: a quantitative analysis using plain radiography and computed tomography. Ann. Rheum. Dis. 68, 1290–1295 (2009). 4. Thiele, R. G. & Schlesinger, N. Diagnosis of gout by ultrasound. Rheumatology 46, 1116–1121 (2007). 5. Kottgen, A. et al. Genome-wide association analyses identify 18 new loci associated with serum urate concentrations. Nat. Genet. 45, 145–154 (2013). 6. Choi, H. K., De Vera, M. A. & Krishnan, E. Gout and the risk of type 2 diabetes among men with a high cardiovascular risk profile. Rheumatology 47, 1567–1570 (2008). 7. Hollis-Moffatt, J. E. et al. Role of the urate transporter SLC2A9 gene in susceptibility to gout in New Zealand Maori, Pacific Island, and Key advances ■■ Regression and possible healing of radiographic erosions can occur with aggressive urate-lowering therapy1 ■■ Genes that modulate glucose metabolism are associated with hyperuricaemia, linking different features of the metabolic syndrome5 ■■ Effective gout flare prophylaxis using IL-1β blockade can be achieved in many patients initiating urate-lowering therapy8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 78. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB RHEUMATOLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  69 IMAGING IN RHEUMATOLOGY IN 2013 From images to data to theory Felix Eckstein and C. Kent Kwoh 2013 has witnessed the maturation of imaging science with rheumatology research, in part due to large, public databases. Using imaging in osteoarthritis (OA) as an example, breakthroughs include further elucidation of the relationship between obesity and OA, and identification of the importance of bone and meniscus shape in OA development. Eckstein, F. & Kwoh, C. K. Nat. Rev. Rheumatol. 10, 69–70 (2014); published online 24 December 2013; doi:10.1038/nrrheum.2013.198 For the past few decades, imaging research in rheumatology has led the life of a ‘sleep- ing beauty’: somewhat self-centred and nar- cissistic, it has kept itself busy with technical advancements and development of a pleth- ora of novel image acquisition approaches. But imaging research has recently matured, becoming a more productive and integrated ‘member’ of the research community. Pro­ gresshasbeendrivenbysemiquantitativeand quantitative image analysis methodology, and the availability of large, public databases, such as the Osteoarthritis Initiative (OAI),1 that permit researchers worldwide to access images and measurements (along with rele- vant clinical data), considerably widening the expertise available. Given this momentum, we focus on imaging research from 2013, using imaging in osteoarthritis (OA) research as an example of the clinical and practical use of imaging in rheumatology (Figure 1). The relationship between obesity and OA is well established, but, now, the mechanical pathogenic mechanisms have been supple- mented by identification of proinflamma- tory mediators secreted by adipose tissue that can promote articular tissue degrada- tion. Leptin seems to be a crucial mediator of obesity-associated OA, synergistically acting with other inflammatory cytokines. In 2013, Stannus and co-workers2 reported that serum leptin levels were negatively associated with knee cartilage thickness (measured quantitatively with MRI). BMI, trunk and total body fat were also negatively associated with knee cartilage thickness, but these associations disappeared after adjust- ment for serum leptin levels, indicating that leptin could mediate the association between obesity and cartilage thickness. Prospectively, leptin levels were associated with longitudi- nal thinning of media tibial cartilage in the participants, most of whom had radiographic knee OA (ROA). The researchers proposed that leptin acts in a biphasic manner, induc- ing anabolic chondrocyte activity and bene­ ficial effects on cartilage physiologically, but also catabolic cartilage tissue degradation when present in excess. Further work sug- gested that the association of obesity and OA also extends to early tissue alterations before ROA.3 Studying OAI incident cohort partici- pants without ROA, statistically significant relationships were reported between meta- bolic risk factors (high abdominal circum- ference, hypertension, high fat consumption and self-reported diabetes) and femorotibial cartilage transverse MRI relaxation times (T2), a marker of tissue hydration and col- lagen derangement.3 Cross-sectionally, T2 increased in a dose-response manner with the number of metabolic risk factors; how­ ever, these factors were not associated with longitudinal change in T2, suggesting that T2 progression could be a less sensitive measure of longitudinal outcome once car- tilage lesions occur.3 A more complex T2 texture index4 efficiently helped differenti- ate OAI participants with ROA risk factors from healthy individuals, and OAI partici- pants with worsen­ing knee symptoms over 3 years from those without. Imaging is not limited to measuring effects of obesity on synovial joint structure, it can also help delineate local adipose tissue mass. Notable differences in thigh intermuscular adipose tissue volume (IMF) were reported between female OAI participants with and without ROA, which were not paral- leled by differences in quadriceps muscle Caucasian case–control sample sets. Arthritis Rheum. 60, 3485–3492 (2009). 8. Mitha, E. et al. Rilonacept for gout flare prevention during initiation of uric acid-lowering therapy: results from the PRESURGE2 international, phase 3, randomized, placebo- controlled trial. Rheumatology 52, 1285–1292 (2013). 9. Schlesinger, N. Treatment of chronic gouty arthritis: it is not just about urate-lowering therapy. Semin.Arthritis Rheum. 42, 155–165 (2012). 10. Liu-Bryan, R. & Terkeltaub, R. Evil humors take their toll as innate immunity makes gouty joints TREM-ble. Arthritis Rheum. 54, 383–386 (2006). Pre-ROA d e Endocrine (systemic) factors Adipokines and proinflammatory cytokines (e.g. leptin) associated with adipose tissue, causing low-grade inflammation b Mechanical factors High loads; bone shape, meniscus position; muscle weakness due to pain and/or adipose tissue accumulation a c ROA Figure 1 | Factors potentially involved in obesity-induced ROA. Axial MRI of the thigh, a | muscle tissue (quadriceps, green; hamstring, red; adductors, blue; sartorius, violet) and b | adipose tissue (subcutaneous fat, yellow; intermuscular tissue, red). c | 3D MRI reconstruction of a knee (lateral view; adipose tissue, dark red; meniscus, bright red; tibial cartilage, yellow; anterior cruciate ligament, blue; posterior cruciate ligament, green). d | Sagittal T2 map of femorotibial cartilage of a pre-ROA compositional T2 lesion (values: high, blue; low, red; intermediate, green). e | Fixed flexion radiograph of ROA. Abbreviations: ROA, radiographic knee osteoarthritis. Parts a and b courtesy of A. Ruhdorfer, d courtesy of J. Tamez-Peña, and c and e from the Osteoarthritis Initiative database. © 2014 Macmillan Publishers Limited. All rights reserved
  • 79. S70 www.nature.com/nrrheum/collections/xxxx RHEUMATOLOGY 70  |  JANUARY 2014 www.nature.com/reviews volume.5 Thigh IMF explained as much of the variability in physical knee function as ROA status did (more so than quadriceps volume), and this information only partially overlapped with that from BMI. Obesity is an interesting OA risk factor as it is modi- fiable. A randomized controlled trial inves- tigated whether a ≥10% reduction in body weight over 18 months induced by diet (with or without exercise) would improve mec­ ha­nistic and clinical outcomes more than exer­cise alone.6 Diet plus exercise was the most effective at achieving weight loss; this group also had the least knee pain and best physical function. The diet-only group had significantly lower compressive joint forces and IL‑6 plasma levels than the ­exercise-only group. Further imaging studies are needed to explore whether improvement in knee symp- toms and function are related to thigh IMF or to structural improvement of the joint. Another important step forward in 2013 was that Kerkhof et al.7 developed and vali- dated comprehensive prognostic models for incident knee ROA in three independent, population-based studies. Sex, age and BMI provided moderate prediction of incident ROA, but addition of further questionnaire variables, genetic score and biochemical markers (specific to type II collagen) did not improve the prediction.7 The strongest predictor was a subtle change in bone shape observed on baseline knee radiographs (Kellgren–Lawrencegrade1).7 Moresophisti- catedmeasuresofMRI-based3Dboneshape, using active appearance modelling and linear discriminant analysis, have been explored.8 Knees with greater vectors of whole-knee 3D bone shape were more likely to develop incident ROA 12 months later. The associa- tion was strongest among those with normal radiographs (Kellgren–Lawrence grade 0). Application of quantitative MRI measure­ ment technology to cartilage has been around for two decades, but their applica- tion to the meniscus is more recent. In 2013, Son et al.9 characterized the variability of magnetic resonance relaxation mecha­nisms (T2 and T1rho) across different regions of human menisci from patients with ROA. Both measures strongly correlated with tis­sue hydration, but the correlation with col­la­gen and glycosaminoglycan content depended on normalization to dry versus wet tissue mass. The authors found moderate correla- tion of T2 and T1rho with tissue mechanical properties, such as e­quilibrium–dynamic compressive and dynamic shear moduli.9 Variation in water content therefore might determine most of the variation of T2, T1rho and mechanical properties in osteoarthritic menisci, and further exploration at earlier disease stages was advocated.9 Further­more, 3D morphometric measures of menis­cus shape and position have been developed (Figure 1c) and used to resolve discrepan- cies between different imaging modali- ties and measures.10 In a between-knee, within-person comparison of contralateral knees with and without joint-space width (JSW) narrowing from OAI participants, alongside our colleagues, we observed a statistically significant relationship between side-­differences in medial radiographic JSW with the percentage of tibial plateau cover- age by the medial meniscus (coefficient of determination [r2 ] ≈ 25%), but low correla- tion coefficients for other meniscus meas- ures.10 The correlation of radiographic JSW with cartilage thickness was strongest for the central aspect of the medial, weight-bearing femur (r2  ≈ 50%), whereas other femorotibial subregions had lower coefficients. Excluding knees with nonoptimal alignment between the tibial plateau and X‑ray beam, correla- tion with femoral cartilage thickness with radiographic JSW increased (r2  ≈ 65%), suggesting that JSW provides an improved representation of (central) femoral cartilage thickness when radiographic positioning is optimal.10 Major advances have been made in 2013 to turn images into data, and to use these data to develop novel or more detailed theo- ries about the pathophysiology of OA. The OAI is in its eighth year of follow-up; this and other cohort studies will continue to provide long-term clinical and imaging out- comes into 2014 and beyond. Qualification of meaningful imaging biomarkers might facilitate clinical trials to test the efficacy of structure (or disease)-modifying OA drugs. Institute of Anatomy, Paracelsus Medical University, Strubergasse 21, Salzburg A5020, Austria (F. Eckstein). Division of Rheumatology and University of Arizona Arthritis Center, University of Arizona, 1501 North Campbell Avenue,Tucson,AZ 85724, USA (C. K. Kwoh). Correspondence to: F. Eckstein felix.eckstein@pmu.ac.at Acknowledgements We thank all involved with the Osteoarthritis Initiative (OAI) for the public imaging data. The OAI is a public– private partnership comprising five contracts (N01-AR‑2-2258; N01-AR‑2-2259; N01-AR‑2-2260; N01-AR‑2-2261; N01-AR‑2-2262) funded by the NIH, and conducted by the OAI Study Investigators. Private funding partners of the OAI include Merck Research Laboratories, Novartis Pharmaceuticals Corporation, GlaxoSmithKline and Pfizer. Private funding for the OAI is managed by the Foundation for the NIH. This manuscript was prepared using images from an OAI dataset and does not necessarily reflect the views of the OAI investigators, NIH, or private funders. Competing interests F. Eckstein declares associations with the following companies: Abbvie, Chondrometrics GmbH, Eli Lilly, GlaxoSmithKline, Kolon, Janssen Pharmaceuticals, Medtronic, MerckSerono, Novartis, Pfizer, Sanofi Aventis, Stryker, Synarc, Synthes, Wyeth. C. K. Kwoh declares associations with the following companies: Pfizer, Novartis. See the article online for full details of the relationships. 1. OAIOnline, University of California San Francisco. Osteo-Arthritis Initiative [online], http://oai.epi-ucsf.org/datarelease (2013). 2. Stannus, O. P. et al. Cross-sectional and longitudinal associations between circulating leptin and knee cartilage thickness in older adults. Ann. Rheum. Dis. http://dx.doi.org/ 10.1136/annrheumdis‑2013‑203308. 3. Jungmann, P. M. et al. Metabolic risk factors are associated with cartilage degradation assessed by T relaxation time at the knee. Arthritis Care Res. (Hoboken) 65, 1942–1950 (2013). 4. Urish, K. L. et al. T2 texture index of cartilage can predict early symptomatic OA progression: data from the osteoarthritis initiative. Osteoarthritis Cartilage 10, 1550–1557 (2013). 5. Maly, M. R. et al. Relationship of intermuscular fat volume in the thigh with knee extensor strength and physical performance in women at risk of or with knee osteoarthritis. Arthritis Care Res. (Hoboken) 1, 44–52 (2013). 6. Messier, S. P. et al. Effects of intensive diet and exercise on knee joint loads, inflammation, and clinical outcomes among overweight and obese adults with knee osteoarthritis: the IDEA randomized clinical trial. JAMA 12, 1263–1273 (2013). 7. Kerkhof, H. J. et al. Prediction model for knee osteoarthritis incidence, including clinical, genetic and biochemical risk factors. Ann. Rheum. Dis. http://dx.doi.org/10.1136/ annrheumdis‑2013‑203620. 8. Neogi, T. et al. Magnetic resonance imaging- based three-dimensional bone shape of the knee predicts onset of knee osteoarthritis: data from the osteoarthritis initiative. Arthritis Rheum. 8, 2048–2058 (2013). 9. Son, M. et al. Regional variation in T1rho and T2 times in osteoarthritic human menisci: correlation with mechanical properties and matrix composition. Osteoarthritis Cartilage 6, 796–805 (2013). 10. Bloecker, K. et al. Contribution of regional 3D meniscus and cartilage morphometry by MRI to joint space width in fixed flexion knee radiography‑A between-knee comparison in subjects with unilateral joint space narrowing. Eur. J. Radiol. 82, e823–e839 (2013). Key advances ■■ Leptin has a central role in mediating the association between obesity, MRI-based quantitative measurement of cartilage thickness loss and the progression of knee osteoarthritis (OA)2 ■■ Subtle changes in radiographic bone shape markedly improved the prediction of future incident knee OA7 ■■ Regional variability in MRI transverse relaxation times (T2 and T1rho) of OA meniscal tissue reflects variability in tissue hydration and mechanical properties9 © 2014 Macmillan Publishers Limited. All rights reserved
  • 80. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB RHEUMATOLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  71 SYSTEMIC LUPUS ERYTHEMATOSUS IN 2013 Taking a closer look at biologic therapy for SLE David A. Isenberg and Anisur Rahman Clinical, basic and translational research in systemic lupus erythematosus are fast-moving fields. 2013 has seen the publication of some potentially landmark papers, which not only explore the potential of novel agents but also glean new insights from past trials. Isenberg, D. A. & Rahman, A. Nat. Rev. Rheumatol. 10, 71–72 (2014); published online 17 December 2013; doi:10.1038/nrrheum.2013.203 For 60 years corticosteroids have been widely used in the treatment of most aspects of sys- temic lupus erythematosus (SLE). They have proved life-saving drugs; however, a ten- dency to use them at rather too high a dose for too long has led to a plethora of serious adverse effects including osteo­porosis and infection. Furthermore, Eder and col- leagues1 have shown that st­eroids make a major contribution to permanent damage in SLE which, if acquired early, predicts poor prognosis.2 Although the biologic era is well established in the manage­ment of rheuma- toid arthritis, virtually all clinical trials of biologic agents for SLE have failed to meet their end points (the trials of belimumab, which we discuss later, remain the ‘honour- able’ exception). Many questions have been asked about the reason for this failure. 2013 has seen the publication of several studies that both encourage the view that biologic drugs do have a part to play in SLE treatment and also help to explain why earlier trials were deemed unsuccessful. Thus, the publication by Condon et al.,3 showing that treatment of patients with lupus nephritis with rituximab-based therapy might reduce the need for oral steroids, is novel and potentially exciting. In this observational study of 50 newly diagnosed, biopsy-proven cases of lupus nephritis treated with rituximab and low- dose mycophenolate, only two patients required oral steroids after 2 years of follow up. Encouragingly, 52% (n = 26) of the patients in the study had gone into full remission at 1 year. These data support and extend a smaller study of eight patients with SLE (only one had renal disease) treated at diagnosis with rituximab and azathioprine with similar steroid-sparing effects.4 B‑cell depletion using rituximab also remains widely used to treat patients with estab- lished SLE who have failed to respond to conventional therapies, despite the failure of the EXPLORER5 and LUNAR6 studies to meet their primary end points. However, two questions remain about the use of rituximab: firstly, what factors determine when B cells will return (our experience of treating >100 patients with SLE is that the mean time for B‑cell return is 6 months but it varies from 2 months to over 12 years [D. A. Isenberg, unpublished data]), and se­condly, what determines the variation in the time to return of clinical features follow- ing the reappear­ance of B cells? The answers are likely to be dependent upon subtleties in the cellular response to B‑cell deple- tion. With this point in mind, the ability of B‑cell depletion to correct abnormalities in ­invariant natural killer T cells is notable.7 Proposed explanations for the failure of earlier trials of a range of biologic agents in SLE include excessive use of concomitant steroids and immunosuppressive agents, and ‘setting the bar too high’ to give the bio- logic drug a realistic chance of succeeding. Wofsy et al.8 have now provided a thought- provoking re-analysis of data presented in a trial deemed to have been a failure—a 12-month, phase II/III multicentre ran­ domized, double-blind placebo-controlled trial of abatacept in 300 patients with lupus nephritis who received background treat- ment with mycophenolate and steroids. Using the infor­mation ga­thered in the trial, a wide variety of outcome measures was reassessed, looking at both 24 and 52 weeks of follow-up. The authors found that the optimal measures were complete response at 52 weeks (defined as urine protein to creati­nine ratio [UPCR] <0.5, inactive urine sediment, and return to normal serum creati­nine levels or, for patients with normal serum creatinine levels at baseline, final value within 15% of baseline), major clini- cal response (defined as complete response or, for patients with UPCR >3 at baseline, achievement of UPCR <1 and meeting all of the other criteria for complete response), and time to complete response. These outcome measures would have judged the trial a success, as opposed to the original, more rigorous, primary endpoint of the study, which defined a complete response as UPCR <0.26, serum creatinine within 10% of baseline level and inactive urine sediment, all present on two successive visits. With the caveat, as discussed by the authors, that this analysis looked at a single trial of a single drug, it nevertheless offers encouragement that the careful selection of sensitive outcome measures is likely to be vital in demonstrating statistically sig- nificant differences between trial drugs and placebo. The use of such measures might also help to reduce the numbers of patients that need to be recruited for clinical trials. The disappointing results from clinical trials of rituximab in patients with SLE5,6 have focused interest on alternative bio- logic agents. Belimumab, which targets B‑cell activating factor, met its primary end­point in two clinical trials (reviewed by Kandala et al.9 ) and has been approved for the treatment of SLE by regulatory authori- ties in the USA and the European Union. Evidence from those studies suggests that this drug might be particularly effective in patients with low levels of complement and high levels of antibodies against double- stranded DNA, which will be helpful to Key advances ■■ Treatment with rituximab and mycophenolate in newly diagnosed lupus nephritis gives good clinical outcomes without any requirement for oral corticosteroids3 ■■ Using different outcome measures in trials of biological agents in lupus nephritis might enable more-sensitive detection of beneficial effects8 ■■ A trial of epratuzamab showed that this agent is safe and potentially effective in the treatment of SLE, and described a novel responder index for use in clinical trials in SLE10 NPG © 2014 Macmillan Publishers Limited. All rights reserved
  • 81. S72 www.nature.com/nrrheum/collections/xxxx RHEUMATOLOGY 72  |  JANUARY 2014 www.nature.com/reviews clini­cians in deciding which patients to treat with belimumab. Epratuzamab is a humanized mono­ clonal anti-CD22 antibody, which modi- fies the activation of B lymphocytes and produces less B‑cell depletion than rituxi- mab. In 2013, Wallace et al.10 published the results of the EMBLEM study—a phase IIb dose-ranging, randomized, double-blind, placebo-controlled trial of epratuzamab in 227 patients with SLE. Patients with severe renal or cerebral SLE were excluded from this trial. The follow-up period was 12 weeks and the primary outcome measure was responder rate using a novel com- posite outcome measure which, like the composite measure used in the belimu­ mab trials,9 incorporated the SLE Disease Activity Index (SLEDAI), the British Isles Lupus Assessment Group index (BILAG) and a Physician Global Assess­ment (PGA) of disease activity. This new composite measure, designated BICLA (BILAG-based Combined Lupus Assess­ment), defines a responder as some­one whose BILAG score has improved, whereas SLEDAI and PGA are no worse and there is no treatment failure. Con­versely, definition of response in the belimumab studies required improvement in SLEDAI and no worsening of BILAG or PGA.9 In the EMBLEM trial, the responder rate in the placebo group was only 21.1%. This rate is con­siderably lower than in the LUNAR and belimumab studies, which had placebo res­ponse rates of approximately 46% and 44%, respectively.6,9 This difference is impor­tant because high placebo response could be an important reason for the appar- ent failure of biologic drugs in clinical trials. The EMBLEM study identified a dose of 2,400 mg per month, given as either 600 mg weekly or 1,200 mg fortnightly, as being most effective: with these dosages, responses were seen by 8 weeks, and at 12 weeks 45.9% of those who received 600 mg epratuzamab weekly and 40.5% of those who received 1,200 mg fortnightly showed a BICLA response (compared with 21.1% of the placebo group). Serious adverse effects were rare and not related to dose of epratuzamab, and no deaths occurred. Though it is impor- tant to recognize that EMBLEM was not powered to show a statistically significant benefit of epratuzamab over placebo, this study is an important advance as it identifies a safe, well-tolerated and potentially effective dose of this drug in patients with moderately to severely active SLE. The results of longer, larger phase III trials, which have been ­initiated, will be crucial. Thus, 2013 may well be remembered as a time when, after several frustrating years, the potential benefits of biologic therapies in SLE genuinely began to be realized. We hope that 2014 will see more successful trials of biologics in SLE reported, as well as the commencement of other trials using more realistic primary endpoints. Centre for Rheumatology, University College London, Room 424, 4th Floor Rayne Building, 5 University Street, London WC1E 6JF, UK (D. A. Isenberg, A. Rahman). Correspondence to: D.A. Isenberg d.isenberg@ucl.ac.uk Acknowledgements Both authors are supported by the National Institute for Health Research University College London Hospitals Biomedical Research Centre. Competing interests The authors declare no competing interests. 1. Eder, L., Urowitz, M. B. & Gladman, D. D. Damage in lupus patients—what have we learned so far? Lupus 22, 1225–1231 (2013). 2. Rahman, P., Gladman, D. D., Urowitz, M. B., Hallett, D. & Tam, L. S. Early damage as measured by the SLICC/ACR damage index is a predictor of mortality in systemic lupus erythematosus. Lupus 10, 93–96 (2001). 3. Condon, M. B. et al. Prospective observational single-centre cohort study to evaluate the effectiveness of treating lupus nephritis with rituximab and mycophenolate mofetil but no oral steroids. Ann. Rheum. Dis. 72, 1280–1286 (2013). 4. Ezeonyeji, A. N. & Isenberg, D. A. Early treatment with rituximab in newly diagnosed systemic lupus erythematosus patients: a steroid-sparing regimen. Rheumatology (Oxford) 51, 476–481 (2012). 5. Merrill, J. T. et al. Efficacy and safety of rituximab in moderately‑to‑severely active systemic lupus erythematosus: the randomized, double-blind, phase II/III systemic lupus erythematosus evaluation of rituximab trial. Arthritis Rheum. 62, 222–233 (2010). 6. Rovin, B. H. et al. Efficacy and safety of rituximab in patients with active proliferative lupus nephritis: the Lupus Nephritis Assessment with Rituximab study. Arthritis Rheum. 64, 1215–1226 (2012). 7. Bosma, A., Abdel-Gadir, A., Isenberg, D. A., Jury, E. C. & Mauri, C. Lipid-antigen presentation by CD1d+ B cells is essential for the maintenance of invariant natural killer T cells. Immunity 36, 477–490 (2012). 8. Wofsy, D., Hillson, J. L. & Diamond, B. Comparison of alternative primary outcome measures for use in lupus nephritis clinical trials. Arthritis Rheum. 65, 1586–1591 (2013). 9. Kandala, N. B. et al. Belimumab: a technological advance for systemic lupus erythematosus patients? Report of a systematic review and meta-analysis. BMJ Open 3, e002852 (2013). 10. Wallace, D. J. et al. Efficacy and safety of epratuzumab in patients with moderate/severe active systemic lupus erythematosus: results from EMBLEM, a phase IIb, randomised, double-blind, placebo-controlled, multicentre study. Ann. Rheum. Dis. http://dx.doi.org/ 10.1136/annrheumdis-2012-202760. EPIGENETICS IN 2013 DNA methylation and miRNA—key roles in systemic autoimmunity Bruce C. Richardson and Dipak R. Patel Several advances in 2013 have improved our understanding of how epigenetic mechanisms affect autoimmune disorders. Many new insights were made into the regulation of gene expression by DNA methylation in systemic lupus erythematosus. For rheumatoid arthritis, complex interrelationships between DNA methylation and microRNAs in regulating gene expression were described. Richardson, B. C. & Patel, D. R. Nat. Rev. Rheumatol. 10, 72–74 (2014); published online 14 January 2014; doi:10.1038/nrrheum.2013.211 Epigenetics is defined as heritable changes in gene expression that are not due to altera­tion of the DNA sequence. Epigenetic mecha- nisms regulate multiple aspects of chroma­ tin structure and function, including the regulation of transcriptionally repressive and permissive configurations for gene expres­sion. These mechanisms include DNA methy­lation, histone modifications including methy­lation and acetylation, and regulation by microRNAs (miRNA). In this 2013 Year in Review, we describe advances (Figure 1) in our understanding of DNA methylation and miRNAs in the patho­ genesis of systemic lupus erythematosus (SLE)1,2 and ­rheumatoid arthritis (RA).3 Genome-wide methylation studies have provided new insights into the role of DNA methylation in the pathogenesis of SLE. Coit et al.1 demonstrated that regulatory regions for interferon-responsive genes in naive CD4+ T cells from patients with SLE are hypomethylated and ‘poised’ for expres- sion; transcription does not occur until © 2014 Macmillan Publishers Limited. All rights reserved
  • 82. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB RHEUMATOLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  73 Key advances ■■ Abnormal DNA methylation exists in CD4+ T cells from patients with SLE before activation and differentiation, although the genes are not expressed until they are activated1 ■■ Overexpression of protein phosphatase 2A in T cells increases expression of proinflammatory methylation-sensitive genes important in SLE pathogenesis2 ■■ DNA methylation and microRNAs can operate in conjunction with, or in opposition to, each other in regulating gene expression in synovial fibroblasts3 Figure 1 | Recent advances in our understanding of epigenetics and gene expression. Coit et al.1 showed certain genes are ‘poised’ for transcription, based on methylation of their regulatory regions, but transcription does not occur until the cells are activated. Sunahori et al.2 demonstrated that PP2A blocks signalling pathways that maintain DNA methylation patterns in dividing immune cells, causing them to be overexpressed. De la Rica et al.3 found that DNA methylation and microRNAs can work together, or in opposition, in regulating gene expression. Abbreviations: DNMT1, DNA (cytosine‑5)-methyltransferase 1; MEK, dual specificity mitogen-activated protein kinase kinase; PP2A, protein phosphatase 2A. T-cell activation. Using two independent SLE cohorts, >485,000 genomic methylation sites were analysed by array. The researchers identified 47 genes as differentially methy­ lated, either hypomethylated or hyper- methylated, in a comparison of naive CD4+ T cells from healthy individuals and patients with SLE. Methylation did not increase or decrease with disease activity, as measured by the SLE disease activity index. Bisulphite sequencing confirmed that 35 genes were hypomethy­lated, and most of these genes are involved in type I interferon signalling. Many of the hypomethylated genes were known to be overexpressed in total CD4+ T cells from patients with SLE, but methy­ lation state and expression had not previ- ously been studied in the same naive CD4+ T cell. Coit et al.1 found that none of the hypomethylated genes were overexpressed in naive CD4+ T cells. This discordance between gene accessibility and expression could be explained by the relative paucity and inactive state of transcription factors in naive CD4+ T cells. The changes in DNA methylation before activation and differen- tiation indicate that naive cells are ‘poised’ to express those genes even in the absence of other immune signals. This model helps explain the increased expression of IFN‑α and type I interferon-inducible genes in patients with SLE. In related work, the same type of genome-wide methylation array was used to analyse B cells, monocytes and CD4+ T cells.4 Prior to this study, B cells and monocytes from patients with SLE had not been examined in this manner. Absher et al.,4 however, did not study gene expres- sion or confirm changes in DNA methyla- tion by bisulphite sequencing. Similar to the findings by Coit et al.,1 most of the hypo- methylated genes were related to the type I interferon signalling pathway. The methyla- tion changes in total CD4+ T cells also did not differ significantly from cell subsets, including naive CD4+ T cells, and they did not vary with disease activity. The molecular mechanisms by which DNA methylation is regulated in patients with SLE is an area of intense ­investigation. DNA (­cytosine‑­5)-methyltransferase 1 (DNMT1) is an ERK-regulated and JNK- regulated enzyme required for maintain- ing methylation patterns in dividing cells. In CD4+ T cells from patients with SLE, the expres­sion of DNMT1 is decreased and the ERK and JNK pathways are disrupted.5 Dis­rupting ERK or JNK signalling in vitro decreases Dnmt1 expression and con­se­ quently increases expression of CD70 and otherproinflammatorymethylation-sensitive genes.6 Furthermore, disrupting either ERK or JNK signalling in transgenic mice results in an SLE-like dis­order characterized by anti-double stranded DNA antibodies and glomerulonephritis.6,7 Despite these find- ings, the mechanisms by which ERK and JNKsignallingaredisruptedareonlypartially understood. Work by Sunahoriet al.2 demon- strated that protein phosphatase 2A (PP2A) contributes to ­disrupted signalling of these pathways in SLE. Evidence indicates that PP2A is over­ expressed in T cells from patients with SLE, compared with T cells from healthy indivi­ duals.8 Protein phosphatases can regulate ERK and JNK signalling, but the specific role of PP2A, if any, in SLE pathogenesis was not previously known. Sunahori et al.2 developed a model linking the overexpres- sion of PP2A in T cells from patients with SLE with changes in methylation-sensitive proinflammatory gene expression. Blocking PP2A expression in vitro increases ERK and MEK activation and, consequently, DNMT1 expres­sion and activity. CD70 and CD11a expres­sion, which are regulated by DNA methylation, were also decreased when PP2A was silenced. These findings suggest that PP2A contributes to SLE pathogenesis by blocking ERK and JNK signalling and DNMT1 activity to enable aberrant over- expression of methylation-sensitive pro­ inflammatory genes. This hypothesis would be amenable to testing in an animal model, similar to previous studies in which the ERK and JNK pathways were individually ­disrupted in transgenic mouse models.6,7 DNA methylation and histone modifica- tions regulate gene expression at the level of mRNA transcription, and miRNAs regulate gene expression post-transcriptionally.9 The role of miRNAs in autoimmune diseases is increasingly recognized, and a major advance was reported in 2013. De la Rica et al.3 linked DNA methylation, miRNA expression, and mRNA expression in synovial fibroblasts by using a genome-wide methylation array to identify >1,200 genes that are differentially methylated in six patients with osteo­arthritis (OA) compared with six patients with RA. An analogous study by Nakano et al.10 reported similar changes in DNA methyla- tion patterns. De la Rica et al.3 integrated the methylation data with two different data sets. First, methylation data were compared with mRNA expression data from synovial fibroblasts from patients with RA and OA. With some exceptions, most of the hypo­ methylated genes had overexpressed mRNAs and many of the hypermethylated genes had underexpressed mRNAs, as would be pre- dicted. Next, miRNA expression in synovial fibroblasts from patients with OA or RA was then compared with the methylation data, in particular the location of hyper­ methy­lated and hypomethylated CpG sites in the genome. 11 miRNAs that are down- regulated in patients with RA, compared to patients with OA, were located near hyper- methylated CpG sites, and four miRNAs PP2A MEK DNMT1 (Methylates DNA) Blocks transcription Regulatory regions mRNA Protein Transcription Activation/ stimulus miRNA © 2014 Macmillan Publishers Limited. All rights reserved
  • 83. S74 www.nature.com/nrrheum/collections/xxxx RHEUMATOLOGY 74  |  JANUARY 2014 www.nature.com/reviews that are upregulated were located near hypo­methylated CpG sites. Finally, all three data sets (genomic methylation, mRNAs and miRNAs) were compared simultaneously. De la Rica et al.3 split the results of their complex analysis into groups that suggest the roles of DNA methylation and miRNAs in regulating gene expression. One group con- sisted of downregulated mRNAs with hyper- methylated DNA and increased expression of targeting miRNAs. In this group, DNA methylation and miRNAs work together to suppress gene expression. In a second group of downregulated mRNAs, corresponding DNA elements were hypomethylated, but thenumberofmiRNAsthatspecificallytarget that mRNA were increased. In this second group, miRNAs seemed to have a dominant effect on gene expression. In a third group of downregulatedmRNAs,correspondingDNA elementswerehypermethylatedandtargeting miRNA levels were decreased. In this group, the dominant effector of gene expression was DNA methylation. Analogous groups of upregulated mRNAs were also found. This is the first report to study the integration of effects of DNA methylation and miRNAs on the pathogenesis of an autoimmune dis­order. Despitethesmallsamplesizesinvolved,many oftheresultsfromthemethylationscreenand mRNA expression profiles overlap with pre- viously reported work. This research high- lights the importance of multiple layers of control in regulating gene expression, and it identifies many new potential therapeutic targets.Italsosupportstheroleofother,asyet unidentified,moleculesinthepathogenesisof RA, possibly explaining the discordant effects that DNA methylation and miRNAs can have on gene expression. These three reports indicate an impor- tant role for miRNA and DNA methylation dysregulation in the pathogenesis of SLE and RA. The maintenance of DNA methyla- tion patterns is sensitive to environmental influences7 and miRNAs might serve as bio- markers and therapeutic targets.3 These data suggest new approaches for the diagnosis and treatment of autoimmune diseases. Ann Arbor Veterans Administration Medical Center, Department of Medicine (B. C. Richardson), Department of Rheumatology/Immunology (D. R. Patel), University of Michigan, 3007 BSRB, 109 Zina Pitcher Place,Ann Arbor, MI 48109-2200, USA. Correspondence to: B. C. Richardson brichard@med.umich.edu Acknowledgements This work was supported by PHS grants AR42525 and ES017885, and a Merit Grant from the Department of Veterans Affairs. Competing interests B. C. Richardson declares associations with the following company: IGNYTA. See the article online for full details of the relationship. D. R. Patel declares no competing interests. 1. Coit, P. et al. Genome-wide DNA methylation study suggests epigenetic accessibility and transcriptional poising of interferon-regulated genes in naive CD4+ T cells from lupus patients. J. Autoimmun. 43, 78–84 (2013). 2. Sunahori, K. et al. The catalytic subunit of protein phosphatase 2A (PP2Ac) promotes DNA hypomethylation by suppressing the phosphorylated mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK)/phosphorylated ERK/ DNMT1 protein pathway in T‑cells from controls and systemic lupus erythematosus patients. J. Biol. Chem. 288, 21936–21944 (2013). 3. de la Rica, L. et al. Identification of novel markers in rheumatoid arthritis through integrated analysis of DNA methylation and microRNA expression. J. Autoimmun. 41, 6–16 (2013). 4. Absher, D. M. et al. Genome-wide DNA methylation analysis of systemic lupus erythematosus reveals persistent hypomethylation of interferon genes and compositional changes to CD4+ T‑cell populations. PLoS Genet. http://dx.doi.org/ 10.1371/journal.pgen.1003678. 5. Deng, C. et al. Decreased Ras‑mitogen‑ activated protein kinase signaling may cause DNA hypomethylation in T lymphocytes from lupus patients. Arthritis Rheum. 44, 397–407 (2001). 6. Sawalha, A. H. et al. Defective T‑cell ERK signaling induces interferon-regulated gene expression and overexpression of methylation- sensitive genes similar to lupus patients. Genes Immun. 9, 368–378 (2008). 7. Gorelik, G. J., Yarlagadda, S. & Richardson, B. C. Protein kinase Cδ oxidation contributes to ERK inactivation in lupus T cells. Arthritis Rheum. 64, 2964–2974 (2012). 8. Katsiari, C. G., Kyttaris, V. C., Juang, Y. T. & Tsokos, G. C. Protein phosphatase 2A is a negative regulator of IL‑2 production in patients with systemic lupus erythematosus. J. Clin. Invest. 115, 3193–3204 (2005). 9. Bartel, D. P. MicroRNAs: genomics, biogenesis, mechanism, and function. Cell 116, 281–297 (2004). 10. Nakano, K., Whitaker, J. W., Boyle, D. L., Wang, W. & Firestein, G. S. DNA methylome signature in rheumatoid arthritis. Ann. Rheum. Dis. 72, 110–117 (2013). RHEUMATOID ARTHRITIS IN 2013 Translational medicine in RA —time for change Pierre Miossec With every passing year, research on the pathogenesis of rheumatoid arthritis benefits from discoveries in other scientific fields. Three of the best examples that illustrate the benefit of such interdisciplinary bridges and the effects they have on our understanding of rheumatoid arthritis are presented here. Miossec, P. Nat. Rev. Rheumatol. 10, 74–76 (2014); published online 14 January 2014; doi:10.1038/nrrheum.2013.204 2013 was a prolific year for publication of research related to rheumatoid arthritis (RA) and many criteria could be used to select the three most interesting papers. An obvious aspect to be considered is how the research could change the future—will it lead to a cure? But when do you judge the final effect of a discovery? It takes at least 10 years to move from concept to clinical trials. Research from other fields should also be considered, such as those studies with a global vision of health and disease, and from journals that are not commonly read by rheumatologists. Finally, the major bias for this Year in Review is personal interest and contribution to the field. Combining these aspects, I have selected three studies pub- lished in 2013 for their importance to our current understanding of RA pathogenesis. Given my work on IL‑17 and T cells,1 it is probably no surprise to some that I have selected a paper examining the balance of type 17 helper T (TH 17) cells and regula- tory T (TREG ) cells in the context of RA. A key function of TREG cells is to control immune reactions and to suppress the emergence and development of auto­immunity. Thus, in chronic inflammatory diseases such as RA, it is not surprising that impaired TREG  cell func- tion has been identified, although it is still unclear whether total cell numbers, or just cell functions, are modified. Nie et al.2 estab- lished a functional link between TREG  cells, TNF, and the pathogenesis of chronic RA. They found a defect in TREG cell function as a consequence of abnormal phosphorylation of forkhead box protein P3 (FOXP3), the key transcription factor for TREG cell function. © 2014 Macmillan Publishers Limited. All rights reserved
  • 84. NATURE CLINICAL COLLECTIONS | TITLE OF COLLECTION SB RHEUMATOLOGY KEY ADVANCES IN MEDICINE JANUARY 2014  |  75 Figure 1 | Translational medicine and clinical development. Current regulations regarding the clinical trial of novel pharmaceuticals require that efficacy is first demonstrated in two animal models of disease. Seok et al.6 indicate that there is a poor correlation between genetic targets in human and mouse studies. Lee et al.7 is a good example, however, of translational medicine connecting human patient genetic data from in vitro experiments with mouse models. Nie et al.2 used patient samples, not mice, to demonstrate the basic mechanisms of drug targeting. Alternative pathways of translational medicine should, therefore, be considered by clinical trial regulatory agencies. Key advances ■■ The defect in regulatory T cells in patients with rheumatoid arthritis is explained by excess TNF leading to abnormal phosphorylation of FOXP3 and loss of its function2 ■■ Genomic responses in mouse models of inflammatory disease poorly mimic human diseases6 ■■ A single nucleotide polymorphism in FOXO3 links differential outcomes in rheumatoid arthritis and Crohn disease compared to severe malaria7 FOXP3 transcriptional activity, and con- sequently TREG cell suppressive function, is regulated by phosphorylation of Ser418 in the C‑terminal DNA-binding domain. In TREG cells isolated from the blood and syn- ovial fluid of patients with RA, Ser418 is dephosphorylated by protein phosphatase 1 (PP1), which itself is activated by TNF. In the synovial fluid of patients with RA, the level of TNF-induced TREG cell dysfunction corre­ lated with increased numbers of TH 17 and type 1 helper T (TH 1) cells. TREG cell function in the blood was restored in all 10 patients who were treated with infliximab, an anti- TNF antibody. This process was associated with decreased PP1 expression and increased FOXP3 phosphorylation of TREG cells. Thus, by inducing the dephosphorylation of FOXP3, TNF controls the balance between TREG cells and pathogenic TH 17 and TH 1 cells in the joints of patients with RA. Whether this effect is direct, or indirect by induction of IL‑6 and other cytokines, remains to be determined. Previous studies indicated that IL‑6, which is induced by TNF, regulates the balance of TH 17 and TREG cellsstrongly in favour of TH 17 cells.3,4 Data indicate that, in patients with RA who do not respond or who stop responding to TNF inhibition, the IL‑17–TH 17 pathway is activated resulting in ‘disease flares’, despite blockade of the TNF pathway.5 The work by Nie et al.2 is a good example of combining basic research and modern technology to study differences between clinical samples obtained from healthy individuals and patients. The second study I have chosen to high- light, by Seok et al.,6 provides an introduction to an active debate. When asked at a recent EULAR rheumatology meeting in Rome to discuss whether animal models of RA have led to a better understanding and new treat- ments of the disease, I suggested that none of the current treatments for RA could be clas- sified as resulting directly from experiments first performed in a mouse model of RA. Furthermore, a substantial number of targets first identified from mouse models of RA have not been confirmed as therapeutically relevant during clinical trials in humans. The paper by Seok et al.6 highlighted that no systematic studies have evaluated how well murine models mimic human inflam- matory diseases. In the context of acute inflammatory stress, and focusing only on genes known to be differentially expressed in human diseases, they concluded that there was almost no correlation between changes in expression of mouse genes and their matching human counterparts. The paper has led to numerous associated com- ments and letters, and its importance for the field of RA is reflected by the number of my colleagues in discussion of its content. An optimistic conclusion to be drawn from this work is that we could improve on current animal models and develop the transition of translational medical research from human observations to mouse models, rather than the other way around. At the same time, scien­tific and medical journals have to accept these changes and recognize the importance of clinical research. For such change to occur, the regulatory agencies such as the FDA and EMA will need to remove the prerequisite demonstration of pharmaceutical efficacy in animal models before moving to clinical trials in humans. The third paper I have selected is a study of a particular FOXO3 single nucleotide polymorphism (SNP) (rs12212067: T>G) in patients with RA, Crohn disease or malaria,7 and is a good example of research that combines human genetics of inflamma- tory and infectious disease with an animal model. FOXO3 is a transcription factor involved in the biology of neutrophils and lymphocytes, and overexpression in patients with RA seems to contribute to neutrophil activation.8 Lee et al.7 found the noncoding FOXO3 SNP was associated with disease severity, but not with disease susceptibil- ity. The rare G allele was associated with a milder course of Crohn disease and RA, but increased severity of malaria. To iden­tify the functional consequence of this mar­ker, the authors show that, in response to lipo­ polysaccharide stimulation, monocytes from healthy individuals with the rare allele have a reduced production of pro­inflammatory Drug target selection Regulatory agencies Human samples Nie et al.2 Lee et al.7 Clinical trials (safety, efficacy)Preclinical studies Animal models Human samples In vitro assays Current practice cytokines, including TNF, and an increased production of anti-­inflammatory cytokines, including IL‑10. These changes are related to an increased contribution of the immuno- suppressive cytokine transforming growth factor β1, which is known to inhibit the production of TNF and induce IL‑10. These results indicate a shared genetic contribution to prognosis in distinct diseases. To extend the findings in vivo, Lee et al.7 induced colitis in Foxo3-deficient mice. They found reduced disease severity compared with con- trols, probably because colitis is exacerbated by TNF, and by IL‑10 deficiency. From a long list of papers from 2013, the three I have presented highlight the need to focus on human disease research. This goal could be achieved with the use of native human cells instead of cell lines, and by using mouse models of disease pri- marily for functional studies subsequent to identi­fication of human genetic markers and studies in patient-derived samples,9 effectively reversing the flow of translational medicine (Figure 1). Before this change can happen, efforts are needed to build stronger © 2014 Macmillan Publishers Limited. All rights reserved
  • 85. S76 www.nature.com/nrrheum/collections/xxxx RHEUMATOLOGY 76  |  JANUARY 2014 www.nature.com/reviews bridges between clinicians, researchers and the pharmaceutical industry. Earlier inter­ action with regulatory agencies, and updat- ing of regulatory policies, is also required for example, to enable streamlining of access to samples collected during clinical trials. Proposals to achieve such goals have been made, but a positive move is still needed.10 Department of Clinical Immunology and Rheumatology and the Immunogenomics and Inflammation Research Unit EA 4130, University of Lyon, Hôpital Edouard Herriot, 5 Place d’Arsonval, 69437 Lyon Cedex 03, France. pierre.miossec@univ-lyon1.fr Competing interests The author declares no competing interests. 1. Miossec, P. & Kolls, J. K. Targeting IL‑17 and TH 17 cells in chronic inflammation. Nat. Rev. Drug Discov. 11, 763–776 (2012). 2. Nie, H. et al. Phosphorylation of FOXP3 controls regulatory T cell function and is inhibited by TNF‑α in rheumatoid arthritis. Nat. Med. 19, 322–328 (2013). 3. Bettelli, E. et al. Reciprocal developmental pathways for the generation of pathogenic effector TH 17 and regulatory T cells. Nature 441, 235–238 (2006). 4. McGovern, J. L. et al. TH 17 cells are restrained by TREG cells via the inhibition of interleukin‑6 in patients with rheumatoid arthritis responding to anti-tumor necrosis factor antibody therapy. Arthritis Rheum. 64, 3129–3138 (2012). 5. Alzabin, S. et al. Incomplete response of inflammatory arthritis to TNFα blockade is associated with the TH 17 pathway. Ann. Rheum. Dis. 71, 1741–1748 (2012). 6. Seok, J. et al. Genomic responses in mouse models poorly mimic human inflammatory diseases. Proc. Natl Acad. Sci. USA 110, 3507–3512 (2013). 7. Lee, J. C. et al. Human SNP links differential outcomes in inflammatory and infectious disease to a FOXO3-regulated pathway. Cell 155, 57–69 (2013). 8. Turrel-Davin, F. et al. FoxO3a involved in neutrophil and T cell survival is overexpressed in rheumatoid blood and synovial tissue. Ann. Rheum. Dis. 69, 755–760 (2010). 9. Gregersen, P. K. & Manjarrez-Orduño, N. FOXO in the hole: leveraging GWAS for outcome and function. Cell 155, 11–12 (2013). 10. Miossec, P. et al. Biomarkers and personalised medicine in rheumatoid arthritis: a proposal for interactions between academia, industry and regulatory bodies. Ann. Rheum. Dis. 70, 1713–1718 (2011). © 2014 Macmillan Publishers Limited. All rights reserved
  • 86. Editors’ picks of the year February 2014 volume 10 no. 2 www.nature.com/reviews LOOKING BACK AT 2013 Research advances in gout, imaging, epigenetics and more Looking ahead to the future of RA therapy Emerging cell and cytokine targets RHEUMATOLOGY nrrheum_OFC_FEB14.indd 1 20/01/2014 10:57 * * * * * * * * * * Immunogenicity of anti-TNF biologic therapies for rheumatoid arthritis Pauline A. van Schouwenburg, Theo Rispens and Gerrit Jan Wolbink The presence of anti-drug antibodies (ADA) can result in the loss of response to anti-TNF biologic agents in patients with rheumatoid arthritis (RA). In this article, the authors outline the limitations of current assays for ADA detection and discuss how studying the immune responses caused by the different anti-TNF biologic agents could lead to strategies to help reduce or prevent the development of ADA. doi:10.1038/nrrheum.2013.4 Biologic agents in rheumatology: unmet issues after 200 trials and $200 billion sales John P. A. Ioannidis, Fotini B. Karassa, Eric Druyts, Kristian Thorlund and Edward J. Mills Biologic agents have now been studied in over 200 randomized controlled trials and 100 subsequent meta-analyses in rheumatic diseases. This Review highlights the shortcomings in the evidence derived from such studies. The authors discuss how the issues identified could be addressed in the future by revisiting trial design and improving reporting of findings; the responsibilities of the regulatory authorities, the pharmaceutical industry and academia are also debated. doi:10.1038/nrrheum.2013.134 Future prospects in biologic therapy for systemic lupus erythematosus William Stohl Despite substantial improvements, our current treatments for systemic lupus erythematosus (SLE) still have many limitations, so will new biologic agents be the answer? In this comprehensive Review, Stohl discusses the myriad opportunities biologic agents provide for targeting B cells, T cells and cytokines, and their future potential in SLE therapy. doi:10.1038/nrrheum.2013.136 Back to the future: oral targeted therapy for RA and other autoimmune diseases John J. O’Shea, Arian Laurence and Iain B. McInnes Advances in our understanding of immune cell receptors and the development of biologic agents targeting them have revolutionized the treatment of RA. Now, inhibitors of kinases integral to the signalling pathways downstream of these receptors have been added to the therapeutic armamentarium. This Review discusses the signalling pathways and small-molecule inhibitors of their component kinases that have already shown, or are predicted to show, promise in the treatment of RA. doi:10.1038/nrrheum.2013.7 Immune mechanisms in medium and large-vessel vasculitis Cornelia M. Weyand and Jörg J. Goronzy Giant cell arteritis (GCA) is the most frequent form of large-vessel vasculitis. In this Review, Weyand and Goronzy discuss the aberrant immune pathways that underlie medium and large-vessel vasculitis, focusing on new understanding of the IL-6–IL- 17 and IL-12–IFN-γ cytokine clusters in the development of GCA. Immunostromal interactions are introduced as mechanisms of tissue tropism and disease amplification, and therapeutic interventions targeting vascular instead of immune cells are considered. doi:10.1038/nrrheum.2013.161 Targeting inflammasomes in rheumatic diseases Alexander So, Annette Ives, Leo A. B. Joosten and Nathalie Busso As molecular complexes that promote inflammation, inflammasomes have been implicated in several autoimmune and autoinflammatory disorders, including cryopyrin-associated periodic syndromes and microcrystal-induced pathologies. Here, the authors discuss the roles of inflammasomes in these conditions, as well as their potential involvement in other rheumatic diseases, and consider therapeutic approaches to inhibit inflammasome activity. doi:10.1038/nrrheum.2013.61 TIMELINE: Advances from clinical trials in juvenile idiopathic arthritis Daniel J. Lovell, Nicola Ruperto, Edward H. Giannini and Alberto Martini Many advances in the treatment of juvenile idiopathic arthritis have been underpinned by the development of organizations such as PRINTO and PRCSG. This Perspectives provides a timeline for these advances, including clinical trial designs and diagnostic criteria essential to performing research in this small group of patients whose age necessitates a cautious approach to treatment. doi:10.1038/nrrheum.2013.105 Targeted therapies for systemic sclerosis Christopher P. Denton and Voon H. Ong In the era of targeted therapy, patients with rheumatic diseases have seen real results. But what about those with systemic sclerosis—where is the long-awaited antifibrotic drug? Disparate aspects of the pathogenesis are gradually being integrated into a cohesive model, and molecular targets that are shared with other diseases are also being defined. As this Review stresses, careful evaluation of new strategies, with a focus on learning fundamental lessons about the underlying biology, will be needed to translate novel approaches into actual clinical progress in this recalcitrant disease. doi:10.1038/nrrheum.2013.46 MRI-based semiquantitative scoring of joint pathology in osteoarthritis Ali Guermazi, Frank W. Roemer, Ida K. Haugen, Michel D. Crema and Daichi Hayashi Semiquantitative MRI-based scoring of joint pathology is a powerful tool in osteoarthritis (OA) research, which provides valuable information on the natural history of the disease and can be used in outcome measures. Herein, the authors discuss approaches to semiquantitative MRI-based scoring of OA features and review the scoring systems currently available for whole-joint and feature-specific assessment of knee, hand, hip, spine and shoulder OA. doi:10.1038/nrrheum.2012.223 Duality of fibroblast-like synoviocytes in RA: passive responders and imprinted aggressors Nunzio Bottini and Gary S. Firestein Fibroblast-like synoviocytes (FLS) are cellular effectors of the inflammatory milieu that characterizes and precedes joint destruction in RA. But what role do these cells have in creating the same environment to which they respond? Here, Bottini and Firestein delve into the double life of FLS in RA pathogenesis. doi:10.1038/nrrheum.2012.190 A selection of articles published during 2013 in Nature Reviews Rheumatology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Rheumatology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved
  • 87. KEY ADVANCES IN MEDICINE JANUARY 2014  |  77 UROLOGY TESTICULAR CANCER IN 2013 Towards personalized medicine—are we there yet? Jan Oldenburg and Sophie D. Fosså The pursuit of reduced-intensity treatments for testicular cancer continued with vigour in 2013. For those with metastatic disease and poor prognoses, an alternative to bleomycin, etoposide and cisplatin chemotherapy emerged. These advances suggest we are making progress by reducing treatment intensity with personalized approaches for this highly curable malignancy. Oldenburg, J. & Fosså, S. D. Nat. Rev. Urol. 11, 68–69 (2014); published online 24 December 2013; doi:10.1038/nrurol.2013.298 Although testicular cancer is associated with a high cure rate (99% for men with stage I disease and approximately 50% for those with metastatic disease and poor risk pro­ files at diagnosis), numerous clinical chal­ lenges remain. In 2013, several studies were reported that indicate treating patients with testicular cancer should not follow a ‘one size fits all’ model and that individualized care can improve outcomes even further. The standard treatment of bleomycin, etopo­side and cisplatin (BEP) chemo­ therapy (four rounds) for patients with poor p­rognoses—characterized according to histology, levels of tumour markers and site of origin according to the International Germ Cell Cancer Collaborative Group (IGCCCG)1 —has remained unchanged for the past 25 years. Various phase III trials comparing BEP with alterative chemo­ therapy regimens have not improved survival rates.2 In the Genitourinary Tumor Group (GETUG) 13 study, reported in abstract form, the decline of combined tumour markers (comprising serum α‑fetoprotein [AFP] and human chorionic gonadotropin [HCG]) were assessed at two time points: before the initiation of BEP therapy and at day 21 of the cycle.3 Patients with a ‘favour­ able’ serum tumour marker decline (calcu­ lated according to the half-lives of the markers) were then allocated to four courses of BEP, whereas those with an ‘unfavourable’ decline were randomly assigned to receive either four courses of BEP or a dose-dense regimen consisting of paclitaxel–BEP plus day‑10 oxaliplatin for two cycles, followed by two cycles of cisplatin, ifosfamide, con­ tinuous infusion bleomycin and granulo­cyte colony stimulating factor (G-CSF).3 This bio­ marker strategy had been assessed p­reviously in nonrandomized studies.4,5 Of the 263 patients enrolled in the GETUG study, 254 were evaluable at day 21, 203 of whom had an unfavourable decline. Of these, 98 patients were assigned the standard BEP therapy and 105 patients were assigned the dose-dense regimen. The prognostic value of favourable versus unfavourable tumour marker decline was confirmed by significant differences in 3‑year progression-free sur­ vival (PFS)—70% versus 48%, r­espectively— and in overall survival—84% versus 65%, respectively. In patients with unfavourable tumour marker decline, the 3‑year PFS was 59% and 48% after the dose-dense and the standard BEP chemotherapy, respectively. Unsurprisingly, grade ≥2 neuro­toxicity was more common in the dose-dense arm, as was haematotoxicity, but no difference was observed between the two treatment arms in the rates of febrile neutropenia or toxic death. The need for salvage high-dose chemo­therapy plus stem cell transplanta­ tion in patients with unfavourable tumour marker decline was 6% in the dose-dense arm and 16% in the BEP arm. Given that only 14% of patients with germ cell tumours have a poor prognosis, experts were sceptical whether it would be possible to accrue a sufficient number of men to find a regimen superior to BEP—the researchers are to be congratulated for completing their study. Low recruitment led to the prema­ture closure of an EORTC phase III trial compar­ ing high-dose chemotherapy with BEP in these patients. This is also the first prospec­ tive randomized study using unfavour­able reductions in AFP, HCG or both as pre­ dictive biomarkers to stratify patients into tailor­ed treatment protocols; this might be a viable option for the clinical management of patients in the future. Although chemotherapy has a high success rate in testicular cancer, radiotherapy is a highly effective treatment for abdominal lymph node metastases that do not exceed 5 cm in size (that is, stage IIa and stage IIb disease). However, adjacent, possibly supra­ diaphragmal, lymph nodes might also harbour micrometastases, which will inevi­ tably progress if not included in the radiation field.InmenwithseminomatousstageIgerm cell tumours, micrometastases are effectively targeted using carboplatin chemotherapy as evidenced by a relapse rate of 5%, compared with 20% after surveillance.6 Attempting to leverage the advantages of both radiotherapy and chemotherapy, Horwich et al.7 examined the use of neoadjuvant carbo­platin (AUC 7) with radiotherapy (30 Gy in 15 fractions) in 51 patients with seminomatous stage IIa and stage IIb testicular cancer in a prospec­ tive single-arm study. The authors reported no relapses after a median follow-up dura­ tion of 55 months, and toxi­city was only short-term. The high cure rates and absence of serious acute adverse effects render this treatment approach very promising, especial­ly for patients who are considered unfit for cisplatin-based chemotherapy and in whom a high risk of recurrence is antici­ pated after radiotherapy alone. Ideally, this regimen will now be assessed in a prospec­ tive controlled trial against the current standard of either radiotherapy alone or cisplatin-based chemotherapy.BANANASTOCK © 2014 Macmillan Publishers Limited. All rights reserved
  • 88. 78  |  JANUARY 2014 www.nature.com/reviews UROLOGY With regard to clinical stage I (CSI) non­ seminomatous tumours—the ever more common stage of disease at diagnosis, comprising 66% of cases—2013 welcomed the long-term results of the benefits of reduced-dose adjuvant chemotherapy after orchiectomy. In 2009, Tandstad et al.8 from The Swedish and Norwegian Testicular Cancer Project SWENOTECA reported that men with primary tumour invasion of the testicu­lar vasculature (VASC+) given one round of adjuvant BEP had a 90% reduced risk of relapse compared with those under surveillance and those receiving BEP once relapse was confirmed, reducing the overall chemotherapy burden for these patients. The median follow-up time of 5 years, however, was too short to conclu­ sively show that relapse had been avoided and not merely postponed. At this year’s ASCO meeting Tandstad et al.9 presented their follow-up study, showing consistently low recurrence rates. A total of 491 patients with CSI non­ seminomatous testicular cancer received one course of adjuvant BEP. After a median follow-up of 8 years, 3.4% and 1.3% of the VASC+ and VASC– patients, respec­ tively, had relapsed. By contrast, relapses occurred in 50% and 17% of VASC+ and VASC– patients, respectively, under sur­ veillance (that is, those not receiving adju­ vant treatment). Only one patient had died because of his testicular cancer, with 5‑year and 10-year cancer-specific sur­ vival rates of 100% and 99.6%, respectively, for VASC+ and VASC– patients. With no evidence of late relapses or chemo­therapy resistance after relapse, these data show that one course of adjuvant BEP reduces the risk of relapse in patients with CSI n­onseminomatous germ cell tumour by >90%. Finally, survivorship research was strength­ened in 2013 with the publication of a large-scale study of secondary tumour incidence in men previously treated for testicular cancer. The long latency period (≥10 years) of secondary malignancies has meant that most of the literature has focused on the carcinogenic effects of radiotherapy, which has been a standard treatment for >60 years. Over the past 30 years, cisplatin- based chemotherapy has become more widely applied, and data are now emerging regarding its impact on secondary cancers. Fung et al.10 evaluated secondary solid cancers among 12,691 patients who had not received radiotherapy for their initial treatment. The researchers selected patients with nonseminomatous tumours reported in the population-­based Surveillance, Epidemiology, and End Results (SEER) database between 1980 and 2008 after treat­ ment with either chemotherapy or surgery. Standardized incidence ratios for solid tumours were calculated for the 116,073 person-years of follow-up monitor­ing, during which time 210 secondary solid cancers were observed. The risk of second­ ary solid malignancies was signifi­cantly increased in those who received chemo­ therapy, but was not for those treated with surgery, compared with the general popu­ lation. Furthermore, the increased risk p­ersisted for >20 years after chemotherapy. The weakness of this study is its reli­ ance on SEER data, which do not provide information on the doses of chemotherapy. Presumably, a relationship exists between the cumulative chemotherapy dose and the subsequent risk of late complications (such as secondary cancers), but this has not been conclusively shown. Accordingly, whether adjuvant BEP (one round) for all patients with stage I testicu­lar cancer to lower the cumulative dose is better than sparing chemotherapy for those with established metastases (three or four rounds of BEP) remains unclear. Only high-level evidence from prospective studies will determine this conclusively. 2013 saw the reporting of several impor­ tant findings in the field of testicular cancer. Overall, these data support a common message that the treatment of testicular cancer should be individualized to each patient. For example, in the case of stage I disease, surveillance might not be the best approach for all patients, and for those with metastatic disease, better results might be obtained if dose-dense regimens are used rather than four courses of BEP. In 2014, approximately 25 years after the intro­ duction of BEP for the treatment of testicu­ lar cancer, we will—hopefully—continue to learn how, when and for whom this potent chemotherapy should be applied, and who might be better off without it. Department of Oncology, Oslo University Hospital, Ullernchausseen 70, Oslo 0313, Norway (J. Oldenburg, S. D. Fosså). Correspondence to: S. D. Fosså s.d.fossa@klinmed.uio.no Competing interests The authors declare no competing interests. 1. International Germ Cell Consensus Classification: a prognostic factor-based staging system for metastatic germ cell cancers. International Germ Cell Cancer Collaborative Group. J. Clin. Oncol. 15, 594–603 (1997). 2. Feldman, D. R., Bosl, G. J., Sheinfeld, J. & Motzer, R. J. Medical treatment of advanced testicular cancer. JAMA 299, 672–684 (2008). 3. Fizazi, K., Pagliaro, L. C., Flechon, A. & Mardiak, J. A phase III trial of personalized chemotherapy based on serum tumor marker decline in poor-prognosis germ-cell tumors: results of GETUG 13 [abstract LBA4500]. J. Clin. Oncol. 31 (Suppl.), LBA4500 (2013). 4. Olofsson, S. E. et al. Population-based study of treatment guided by tumor marker decline in patients with metastatic nonseminomatous germ cell tumor: a report from the Swedish- Norwegian Testicular Cancer Group. J. Clin. Oncol. 29, 2032–2039 (2011). 5. Fizazi, K. et al. Early predicted time to normalization of tumor markers predicts outcome in poor-prognosis nonseminomatous germ cell tumors. J. Clin. Oncol. 22, 3868–3876 (2004). 6. Oldenburg, J. et al. Testicular seminoma and non-seminoma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up. Ann. Oncol. 24 (Suppl. 6), vi125–vi132 (2013). 7. Horwich, A., Dearnaley, D. P., Sohaib, A., Pennert, K. & Huddart, R. A. Neoadjuvant carboplatin before radiotherapy in stage IIA and IIB seminoma. Ann. Oncol. 24, 2104–2107 (2013). 8. Tandstad, T. et al. Risk-adapted treatment in clinical stage I nonseminomatous germ cell testicular cancer: the SWENOTECA management program. J. Clin. Oncol. 27, 2122–2128 (2009). 9. Tandstad, T. et al. One course of adjuvant BEP in clinical stage I, nonseminoma: mature and expanded results from the SWENOTECA group [abstract 4553]. J. Clin. Oncol. 31 (Suppl.), a4553 (2013). 10. Fung, C., Fosså, S. D., Milano, M. T., Oldenburg, J. & Travis, L. B. Solid tumors after chemotherapy or surgery for testicular nonseminoma: a population-based study. J. Clin. Oncol. 31, 3807–3814 (2013). Key advances ■■ Unfavourable tumour marker decline predicts very poor prognosis, and should inform treatment; for the first time, an alternative to BEP chemotherapy yielded superior results in patients with poor prognoses3 ■■ Carboplatin plus radiotherapy in patients with seminomatous stage IIa and stage IIb testicular cancer is an alternative to cisplatin-based chemotherapy or radiotherapy alone, and is associated with minimal toxicity7 ■■ Adjuvant BEP in men with stage I nonseminomatous cancer with primary tumour invasion of the vasculature reduces the risk of relapse and overall chemotherapy burden without risk of chemoresistance9 ■■ Although chemotherapy offers very high cure rates, long-term data suggest that the risk of secondary malignancy is considerable10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 89. KEY ADVANCES IN MEDICINE JANUARY 2014  |  79 UROLOGY RECONSTRUCTION IN 2013 Recapitulating the urinary bladder —where are we heading? Arnulf Stenzl In response to the demand for reconstructive options that preserve quality of life after cystectomy, 2013 saw considerable advances in biocompatible meshes and stem cell preparations that might recapitulate the urinary bladder. With increasing strength and functionality of these substitutes, what challenges remain? Stenzl, A. Nat. Rev. Urol. 11, 70–71 (2014); published online 21 January 2014; doi:10.1038/nrurol.2013.315 Every few years, large urology-oriented organizations publish overviews of current practice in treatment centres worldwide, alongside treatment suggestions and guidelines. On the basis of the work of the International Consensus of Urological Disease (ICUD) in collabor­ation with the European Association of Urology (EAU) on various aspects of bladder cancer, Hautmann et al.1 presented an overview of the recent trend towards increased use of urinary bladder reconstruction with ortho­ topic bladder substitution in large-volume centres.However,aworldwide increase in the use of ‘wet stomas’—intestinal conduits and u­reterocutaneostomies—was also noted. By contrast, and similar to the reported decline of uretero­rectosigmoidostomies over the past two decades, the use of continent catheter­ izable abdominal diversions is declining, in part due to an increasing awareness of the long-term complication rate: catheterizable stomas have a high reoper­ation rate after several years and continent reservoirs are susceptible to a higher rate of infection and are prone to stone formation. Thus, ortho­ topic neobladders have replaced continent abdominal reservoirs in women in recent years. However, the reason for the expanded use of ileal conduits instead of orthotopic neobladders or continent abdominal urinary diversion is difficult to explain. One can only speculate that cystectomies are no longer performed by ‘surgeons of excellence’ and, consequently, low-volume surgeons and low- volume hospitals might not be adequately skilled to perform the advanced procedures with the same outcomes.2 The reconstruc­ tive choice might also be influenced by the increasing number of elderly patients (>80 years of age) under­going cystectomy, who are likely to be frail and with comor­ bidities. In either case, surgeons and patients apparently opt for a simpler form of urinary diversion: ileal conduit or, in some cases, even uretero­cutaneostomies. Urologists must clearly address the pressing need for safe but functional bladder r­eplacements that p­reserve quality of life. In patients undergoing cystectomy and subsequent urinary diversion, the use of intestinal segments is the predominant reason for complications. To address this issue, the growth of both urothelial and smooth muscle cells in vitro has been made possible over the past two decades. However, several problems have hindered the clinical use of autologous in vitro engineered tissue for partial or total bladder reconstruction, including scarring of the scaffold used (if necessary) and limited growth of tissue con­ structs beyond a certain size owing to lack of oxygen and nutrients. Indeed, the natural induction of angio­genesis and vascular­ ization occurs late in the tissue-growth process. Furthermore, directed function of the new bladder is d­ifficult to ensure without a­dequate innervation. In searching for biological scaffolds that better imitate the extracellular matrix, researchers have experimented with varia­ tions of biologically absorbable materi­ als.3 Commercially available seamless biocompatible, large-diameter tubular scaf­ folds composed of collagen, which enable adequate vascularization, have demon­ strated the potential for regeneration of the oesophagus. Given that ileal conduits are large-­diameter tubular extensions of the ureters, such tools might have a use in replac­ ing tubular ileum as a simple form of urinary diversion. In 2013, Hoogenkamp et al.4 experimented with several seamless tubular knitted scaffolds reinforced with colla­ gen polymer knitting. These tubes, with an inner diameter of 1.5 cm, were constructed using freezing, lyophilizing and crosslink­ ing techniques. The scaffold was composed of a single layer of porous collagen, a double layer composed of porous and dense collagen or a hybrid layer of collagen and polycapro­ lactone mesh. Only the hybrid layer had the tensile strength needed to maintain a urinary conduit as it passes through the abdominal wall. Omentum wrapped around the hybrid materi­al then induced vascularization of the construct in vivo.4 This bioabsorbable tube with an inner layer of urothelium might serve as an effective and easy-to-prepare replacement conduit, making interruption and isolation of bowel segments unneces­ sary. Large animal studies using xenografted human cells will be n­ecessary to d­emonstrate c­linical usefulness. Over the past two decades data from both men and women have demonstrated the benefit of an orthotopic bladder substi­ tution after cystectomy. These large-volume bladder equivalent reservoirs, with an extended surface area, necessitate sheet- like constructs. In 2013, Tu et al.5 reported the fabrication of silk layers from aqueous solutions of Bombyx mori silk fibroin using a solvent-casting and salt-leaching method in combination with silk film casting. This resulted in bilayered silk scaffolds consisting of porous foams (pore size of ~400 μm) on the luminal side, which were fused to their Thinkstock Key advances ■■ A recent trend towards increased use of orthotopic bladder substitution after cystectomy1 demands the development of safer options, particularly in frail patients ■■ Seamless tubular knitted scaffolds reinforced with collagen polymer and polycaprolactone mesh wrapped in omentum can be vascularized in vivo and have good tensile strength for use as conduits4 ■■ Silk-based scaffolds have high plasticity and can be seeded with muscle cells that demonstrate rudimentary contractility, and might be useful as bladder substitutes5 ■■ Mesenchymal stem cells have the best potential to treat bladder injury6 and can augment muscle mass and improve malfunction of the urinary sphincter8 © 2014 Macmillan Publishers Limited. All rights reserved
  • 90. 80  |  JANUARY 2014 www.nature.com/reviews UROLOGY BLADDER CANCER IN 2013 From genomics to imaging— advances along the care continuum Ahmed Haddad and Yair Lotan 2013 saw the publication of several reports providing insight into a range of ongoing issues in bladder cancer, from screening high-risk candidates to using blue-light cystoscopy to reduce recurrence. These data will strengthen efforts to optimize the detection and treatment of bladder cancer, benefiting patients along the cancer continuum. Haddad, A. & Lotan, Y. Nat. Rev. Urol. 11, 71–73 (2014); published online 10 December 2013; doi:10.1038/nrurol.2013.286 external surface with a homo­geneous, non­ porous silk film. One of the advantages of these constructs—in contrast to the woven collagen tubes used for c­onduits—is their plia­bility. High plasticity and a low incidence of stone formation have also been demon­ strated in animal models. After seeding these scaffolds with autologous urothelial and smooth muscle cells, immunohisto­ chemical analyses revealed good smooth muscle regeneration, and expression of α‑smooth muscle actin and transgelin (also known as SM22‑α), which serve as surrogate markers of contractility, when implanted both in small and large animal models. Parallel to the development of this smooth musculature, multi­layered transitional cell layers—similar to the native urothelium with prominent uroplakin and p63 protein expression—was observed. De novo inner­ vation and vascularization processes were evident in the implanted regenerated tissues, as indicated by Fox3-positive neuro­nal cells and vessels lined with CD31-expressing endothelial cells. A functioning bladder substitute requires contractility, pliability and elasticity (if possible) to fulfil the tasks of the bladder: storage and timed voiding of urine. These results, reported in 2013, put us in good stead to achieve these goals in the near future. The use of stem cells is being explored to further improve the outgrowth of cells and avoid possible oncological problems associated with cells cultivated from the bladder wall of patients with bladder cancer. Mesenchymal stem cells (MSCs) seem to have the best potential to reach clinical status in the near future. Vaegler et al.6 summarized their recent results regarding the source and application of progenitor and stem cells in the functional reconstruction of the lower urinary tract. MSC sub­populations with dif­ ferent surface expression have been defined: CD146+ cells lead to osteogenic differentia­ tion whereas CD146− cells lead to adipose differentiation (thereby avoiding unwanted ossification) and possibly also induce smooth muscle cell differentiation. Indeed, such stem cells derived from bone marrow, adipose tissue and muscle injected into the lower urinary tracts of animal models have been used in recent years to treat a simulated bladder malfunction.7 Furthermore, cell bulk and function have been improved with the addition of nerve growth factor and brain- derived growth factor, resulting in increased smooth muscle mass, neuron density and contractile force.7 Several studies have shown that the concept of a ‘supportive’ cell substitution—injecting cultivated cells into the existing infrastructure of a muscle-cell- deficient organ—can augment muscle mass and improve malfunction of the urinary sphincter.8 In this scheme, the artificial scaf­ folds are wrapped in omentum (or a func­ tional autologous muscle transplant)9 and then seeded with nononcogenic, cultivated urothelial cells10 and smooth muscle cells in different layers. Thus, a usable bladder con­ struction can be achieved without the use of g­astrointestinal segments. With an increasing expectation of good quality of life and a high demand for urinary diversion in elderly frail patients, prefabri­ cated conduits or reservoirs with functional mechanics are being actively pursued. Seeded with autologous cells to ensure func­ tion and embedded into a well-vascularized and innervated native tissue structure, bladder constructions have a good chance of success in the near future. Department of Urology, University Clinic of Urology, Hoppe-Seyler-Strasse 3, 72076 Tübingen, Germany. arnulf.stenzl@med.uni-tuebingen.de Competing interests The author declares no competing interests. 1. Hautmann, R. E. et al. ICUD–EAU International Consultation on Bladder Cancer 2012: urinary diversion. Eur. Urol. 63, 67–80 (2013). 2. Ravi, P. et al. Benefit in regionalisation of care for patients treated with radical cystectomy: a nationwide inpatient sample analysis. BJU Int. http://dx.doi.org/10.1111/ bju.12288. 3. Sun, W. et al. Improving the cell distribution in collagen-coated poly-caprolactone knittings. Tissue Eng. Part C Methods 18, 731–739 (2012). 4. Hoogenkamp, H. et al. Seamless vascularized large-diameter tubular collagen scaffolds reinforced with polymer knittings for esophageal regenerative medicine. Tissue Eng. Part C Methods http://dx.doi.org/10.1089/ ten.TEC.2013.0485. 5. Tu, D. D. et al. Bladder tissue regeneration using acellular bi-layer silk scaffolds in a large animal model of augmentation cystoplasty. Biomaterials 34, 8681–8689 (2013). 6. Vaegler, M., Amend, B., Aicher, W., Stenzl, A. & Sievert, K. D. Stem cell therapy and tissue engineering in regenerative urology [German]. Urologe A 52, 1671–1678 (2013). 7. Sharma, A. K. et al. Cotransplantation with specific populations of spina bifida bone marrow stem/progenitor cells enhances urinary bladder regeneration. Proc. Natl Acad. Sci. USA 110, 4003–4008 (2013). 8. Hart, M. L. et al. Cell-based therapy for the deficient urinary sphincter. Curr. Urol. Rep. 14, 476–487 (2013). 9. van Koeveringe, G., Rademakers, K. & Stenzl, A. Latissimus dorsi detrusor myoplasty to restore voiding in patients with an acontractile bladder—fact or fiction? Curr. Urol. Rep. 14, 426–434 (2013). 10. Vrana, N. E. et al. Engineering functional epithelium for regenerative medicine and in vitro organ models: a review. Tissue Eng. Part B Rev. 19, 529–543 (2013). Bladder cancer continues to be a common malignancy worldwide with a high rate of mortality, particularly among those who present with muscle-invasive disease. Over the past year, several publications have enhanced our understanding of the genetic factors that impact the risk of bladder cancer, aswellasidentifiedpotentialactionablemuta­ tions. Additionally, studies have provided evi­ dence that might improve our manage­ment of both non-muscle-invasive bladder cancer (NMIBC) and m­uscle‑invasiv­e bladder cancer (MIBC). Screening for bladder cancer is not cur­ rently recommended and, as a consequence, the disease is typically detected after blood is visually or microscopically identified in the urine. Smoking is one of the main risk factors for bladder cancer, along with age and gender. Bladder cancer is the sixth most common malignancy, with 72,500 esti­ mated new cases in the USA in 2013. This © 2014 Macmillan Publishers Limited. All rights reserved
  • 91. KEY ADVANCES IN MEDICINE JANUARY 2014  |  81 UROLOGY incidence is still too low to justify wide­ spread screening of all smokers in the popu­ lation.1 However, identifying the smokers who are at the highest risk might enable selection of a population in whom screening or other prevention strat­egies are justified.2 To that end, in a large study of gene– e­nvironment interactions, Garcia-Closas et al.3 examined the associations between 12 single nucleotide polymorphisms (SNPs) and smoking in 3,942 patients with bladder cancer and 5,680 controls from seven pro­ spective cohort and case–control studies. The SNPs included in the study were previ­ ously shown to be associated with increased bladder cancer risk, and included variants of NAT2 and GSTM1.4 Using a polygenic risk score (PRS), a weighted score of the combined effect of all the genetic poly­ morphisms for each individual patient, Garcia-Closas et al.3 showed that patients in the top quartile PRS had a 2.94-fold higher risk of bladder cancer (95% CI 2.32–3.73) than patients in the lowest quartile. Current smokers who were in the highest quartile of PRS had a 6.15-fold (95% CI 3.64–10.42) increased risk of bladder cancer compared with never-smokers in the same PRS quar­ tile. By comparison, former smokers in the highest quartile PRS had a 2.66-fold (95% CI 1.83–3.87) increased risk of bladder cancer compared with never-smokers in the same PRS quartile. The most significant additive interactions between smoking and SNPs were observed for polymorphisms in NAT2 and UGT1A6, both of which encode important enzymes involved in detoxifica­ tion and excretion of aromatic amines. The findings of this study have important impli­ cations from a public health perspective: individuals at the highest genetic risk stand to gain the most from smoking cessation; screening or preventive efforts in this popu­ lation might be effective, although the cost of identifying SNPs will be a limiting factor. Approximately 75% of newly diagnosed bladder cancers are non-muscle-­invasive.2 Patients with NMIBC are at high risk for recurrence after first-line therapy and those with high-grade NMIBC are also at an increased risk of progression. Reducing recurrence in those at the highest risk is of particular importance because these patients are likely to undergo highly inva­ sive procedures, such as cystectomy, if they are deemed to have failed intra­vesical therapies. Preventing recurrence and pro­ gression involves improved detection of high-grade disease at the time of initial resection, improved initial resection tech­ niques and use of intravesical therapies. Several articles reported in 2013 shed light on these strategies. Photodynamic diagnosis, or blue-light cystoscopy, of bladder cancer has been widely studied as a means of improving the detection of bladder tumours and carci­ noma in situ (CIS), but only now are the prospective data mature enough to deter­ mine its usefulness. Although initial studies included both 5‑­aminolevulinic acid and hexylamino­levulinate as photosensitizing agents, the latter is the only photoactive agent approved in Europe and the USA. Burger et al.5 analyse­d the raw data from prospective randomized studies in 1,345 patients with NMIBC who underwent blue- light cysto­scopy with hexylamino­levulinate instillation as an adjunct to white-light cystoscopy. Patients who received 5‑­aminolevulinic acid were excluded, pro­ viding a homogeneous group for analysis. Blue light detected a signifi­cant proportion of Ta tumours (14.7%, P <0.001) and CIS (40.8%, P <0.001) that were not detected by white-light cysto­scopy. Overall recurrence rates were signifi­cantly lower for patients who underwent both blue-light and white- light cystoscopy for their cancer resection compared with those who underwent white-light cysto­scopy alone (34.5% versus 45.4%, P = 0.006). Furthermore, those who underwent blue-light cystoscopy had lower recurrence rates, regardless of whether they had low-risk or high-risk disease. However, the short follow-up duration of the study (1 year) precluded an assessment of pro­ gression rate. Finally, hexyl­aminolevulinate use for cysto­scopy had a similar benefit in patients who had previously received BCG or intravesical chemotherapy compared with those who had not previously received intravesical therapy.5 This study adds to the growing body of evidence that demon­ strates improved clinical outcomes with the use of blue-light c­ystoscopy in the diagnosis of bladder cancer. Despite the widespread use of intra­ vesical BCG in intermediate-risk and high- risk NMIBC, the optimal dose and sched­ ule of intravesical BCG induction and maintenance in patients with NMIBC has been hotly debated. In 2013, the European Organisation for Research and Treatment of Cancer (EORTC) reported the results of a phase III randomized trial looking into this issue. Oddens et al.6 randomly assigned 1,355 patients with high-risk NMIBC into four groups receiving either (standard) full- dose or one-third dose BCG for either 1 year or 3 years of maintenance. The median follow-up duration was 7.1 years. The pre­ specified hypothesis of a 10% decrease in 5‑year disease-free interval was only statisti­ cally observed when comparing patients in the reduced dose for 1‑year arm to those in the full dose for 3‑years arm. The full dose regimen for 1 year was not superior to one-third dose for 1 year, and no significant differ­ences in toxicity between the groups were apparent. With respect to patients with high-risk disease, fewer recurrences occurred in the 3‑year group than in the 1‑year group receiving the full BCG dose. The additional 2 years of maintenance did not deliver obvious benefits to intermediate-­ risk patients receiving full dose BCG. Further studies are needed to elucidate the benefits and costs of these additional 2 years of treatment in this group of patients. A limit­ation of this study was that only 36% of patients assigned to 3 years received the full 36 months of therapy, although half of these patients discontinued BCG because of recurrence. Despite the caveats, the one- third dose for 1 year schedule is suboptimal in most patients; high-risk patients in par­ ticular might benefit from the full dose for 3 years. The different dosing schedules did not seem to affect progression, and further FedericoCaputo/iStock/Thinkstock © 2014 Macmillan Publishers Limited. All rights reserved
  • 92. 82  |  JANUARY 2014 www.nature.com/reviews UROLOGY research is necessary to determine how best to manage patients whose cancer recurs despite receiving BCG treatment. The find­ ings of this large randomized controlled trial have important implications for daily management decisions for patients with NMIBC treated with BCG. Maximizing efficacy of BCG while minimizing toxicity is the goal of BCG therapy; thus, risk strati­ fication of patients as outlined in the study will aid urologists when deciding the dose and timing of BCG. The area of biomarker discovery in bladder cancer has grown dramatically over the past decade. Most biomarker studies have con­siderable limitations, including, but not limited to, small sample size, use of nonstandardized assays and lack of external validation.7 One area of interest is the use of molecular markers to improve staging and risk classification of tumours, which is important because up to 25% of patients classified as having favourable pathologi­ cal features—such as pT1–pT3a without nodal involvement (pN0)—at the time of radical cystectomy experience disease recurrence within 5 years of surgery. This variability in outcomes between patients illustrates the inherent biological and clinical hetero­geneity of bladder cancer. In 2013, Lotan et al.8 reported a prospec­ tive 5‑year validation study of a panel of established bio­markers (cyclin E1, p53, p21, p27 and Ki‑67) selected on the basis of extensive preclinical and clinical data of their importance in bladder cancer pro­ gression and metastasis. After controlling for standard clinical and pathological fea­ tures (including pathological stage, margin status, grade, lymphovascular invasion, lymph node involvement and use of adju­ vant chemotherapy), the number of altered biomarkers was an independent predictor of recurrence and cancer-specific mortality in 216 patients who underwent radical cys­ tectomy and lymphadenectomy. Automated techniques were used to minimize variabil­ ity in immunohistochemical staining and scoring.8 This study provided an example of the staged approach to biomarker dis­ covery; without external validation, the generalizability of findings from biomarker studies is questionable. Further studies are necessary to demonstrate the clinical useful­ness of these tools, but these types of studies serve as a step towards personalized medicine by identifying patients who are at highest risk of recurrence and might be selected for a­djuvant therapies. The development of targeted molecular therapies, although not currently adopted in bladder cancer, is a critical area of future research. Focusing specifically on action­ able drug targets, Iyer et al.9 addressed this important research area in 2013 by exam­ ining genetic copy number alterations in 97 cases of high-grade bladder cancer using comparative genomic hybridization. Actionable drug targets were defined as molecular targets or pathways for which a selective inhibitor is either commer­ cially available or in clinical development. Overall, 61% of tumours harboured an actionable genomic alteration; aberrations in genes within the PI3K/Akt pathway were highly prevalent. To demonstrate the applicability of these findings to targeted drug therapy, the researchers identified cell lines with aberrant PI3K/Akt signalling. Using a highly selective inhibitor of Akt (MK2206), they demonstrated that only cell lines with PIK3CA and AKT mutations (or upstream thereof) were sensitive to MK2206. Thus, they were able to success­ fully target a key aberrant pathway identi­ fied in their genomic analysis. The study had limitations, including the presence of a high number of neuroendocrine tumours in the study sample, and a high proportion of tumours with more than one histological subtype. Further validation of the action­ able targets identified is required. However, the heterogeneity of bladder cancer is such that trials with targeted agents might not show benefits if the population is not enriched with patients who have mutations that are specific to the drugs tested. In summary, controversial areas in the diagnosis and treatment of NMIBC were addressed in 2013. The level 1 evidence from these studies is likely to have a direct impact on daily clinical decision making for patients. Several studies in 2013 also fur­ thered our knowledge of the molecular basis of bladder cancer and gene–­environmental interactions. These studies have impor­ tant implications for future screening and drug development programmes in bladder cancer. The Cancer Genome Atlas sequenc­ ing for bladder cancer will be completed in 2014, which will further our understand­ ing of the genetic characteristics of bladder cancer, and will open future avenues for targeted drug discovery. Department of Urology,The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas,TX 75390-9110, USA (A. Haddad, Y. Lotan). Correspondence to: Y. Lotan yair.lotan@utsouthwestern.edu Competing interests The authors declare no competing interests. 1. Howlader, N. et al. SEER Cancer Statistics Review, 1975–2010. National Cancer Institute [online], http://seer.cancer.gov/csr/ 1975_2010/ (2013). 2. Burger, M. et al. Epidemiology and risk factors of urothelial bladder cancer. Eur. Urol. 63, 234–241 (2013). 3. Garcia-Closas, M. et al. Common genetic polymorphisms modify the effect of smoking on absolute risk of bladder cancer. Cancer Res. 73, 2211–2220 (2013). 4. Garcia-Closas, M. et al. NAT2 slow acetylation, GSTM1 null genotype, and risk of bladder cancer: results from the Spanish Bladder Cancer Study and meta-analyses. Lancet 366, 649–659 (2005). 5. Burger, M. et al. Photodynamic diagnosis of non‑muscle‑invasive bladder cancer with hexaminolevulinate cystoscopy: a meta- analysis of detection and recurrence based on raw data. Eur. Urol. 64, 846–854 (2013). 6. Oddens, J. et al. Final results of an EORTC–GU cancers group randomized study of maintenance bacillus Calmette-Guérin in intermediate- and high-risk Ta, T1 papillary carcinoma of the urinary bladder: one-third dose versus full dose and 1 year versus 3 years of maintenance. Eur. Urol. 63, 462–472 (2013). 7. Shariat, S. F. et al. Statistical consideration for clinical biomarker research in bladder cancer. Urol. Oncol. 28, 389–400 (2010). 8. Lotan, Y. et al. Prospective evaluation of a molecular marker panel for prediction of recurrence and cancer-specific survival after radical cystectomy. Eur. Urol. 64, 465–471 (2013). 9. Iyer, G. et al. Prevalence and co-occurrence of actionable genomic alterations in high- grade bladder cancer. J. Clin. Oncol. 31, 3133–3140 (2013). Key advances ■■ Smokers harbouring particular single nucleotide polymorphisms, such as in NAT2 and GSTM1, might stand to benefit from targeted screening programmes3 ■■ Blue-light cystoscopy has been shown to be more effective than white-light cystoscopy at detecting high-grade non- muscle-invasive bladder cancer (NMIBC) lesions, with concomitant reductions in recurrence rate5 ■■ Patients with high-risk NMIBC should undergo full-dose BCG maintenance therapy after primary resection for 3 years; lower doses for 1 year provide reduced benefit6 ■■ Biomarkers that include cyclin E1, p53, p21, p27 and Ki‑67 might be useful for predicting both recurrence and cancer-specific mortality in patients with bladder cancer8 ■■ Genomic studies identified targets of molecular therapies in bladder cancer, but tumour heterogeneity in this cancer type might hinder clinical development9 © 2014 Macmillan Publishers Limited. All rights reserved
  • 93. KEY ADVANCES IN MEDICINE JANUARY 2014  |  83 UROLOGY FEMALE UROLOGY IN 2013 Evaluating progress on longstanding issues Lindsey Cox and J. Quentin Clemens In 2013, data began to emerge that shed light on several longstanding issues in female urology, from the safety of adrenergic receptor agonists and onabotulinumtoxinA for overactive bladder to the use of physical therapy and mesh suburethral slings for stress urinary incontinence. Cox, L. & Clemens, J. Q. Nat. Rev. Urol. 11, 74–75 (2014); published online 14 January 2014; doi:10.1038/nrurol.2013.320 In 2013, the goals set forth by the Fifth International Consultation on Incontinence were published,1 which emphasized the need for long-term outcomes reporting, including patient-reported outcome measures and the use of standardized definitions and terms for complications. These goals are actively being pursued; for example, treatments for over­ active bladder syndrome (OAB) are being assessed and our understanding of the gold- standard treatments for stress urinary incon­ tinence (SUI) and pelvic organ p­rolapse (POP) continue to improve. In June 2012, Mirabegron (Myrbetriq™; Astellas,USA)becamethefirstβ3-adrenergic receptor agonist to be approved by the FDA for the treatment of OAB. Three large-scale phase III trials that measured safety and effi­ cacy of various doses of mirabegron provided much of the data to support its approval. In 2013, Nitti et al.2 reported the final results of one of these phase III trials, which took place at 132 sites in the USA and Canada between 2008 and 2009. This double-blind, placebo-controlled, randomized clinical trial of 1,328 patients sought to measure the co- primary end points of changes from baseline to final visit for micturitions per 24 h and incontinence episodes per 24 h recorded in a voidingdiary.Thesechangeswerestat­istically significantinboththe50 mgand100 mgdose groups compared with placebo. In terms of the absolute changes in these parameters for patients in the placebo arm, 50 mg mira­ begron and 100 mg mirabegron arms, the mean number of incontinence episodes were reduced by 1.13, 1.47 and 1.63 and voids per 24 h were reduced by 1.05, 1.66 and 1.75, respectively. Subjective questionnaire-based improvements in patient-reported quality of life and treatment satisfaction were also statistically signifi­cant for both treatment arms. Similar findings were reported in a trial conduct­ed in Europe and Australia, which compared an active control—4 mg toltero­ dine (an anti­muscarinic drug)—with mira­ begron;notably,fewerinstancesofdrymouth were reported in the mirabegron arm.3 Adverse event reporting for mirabegron focused on both common and selected cardio­vascular events that could be associ­ ated with adrenergic agonists. When data were pooled for 4,611 patients from these and other phase III trials, the most common adverse events were hypertension (7.3% for mirabegron, 8.1% for tolterodine and 7.6% for placebo), nasopharyngitis (2.4% for mirabegron, 2.8% for tolterodine and 2.5% for placebo) and UTI (3.0% for mirabegron, 2.0% for tolterodine and 1.8% for placebo).4 At 12 weeks, 2.6% of patients discontin­ ued mirabegron because of adverse events, which is a lower discontinuation rate than has often been reported for antimuscarinic medications. The modest objective benefit coupled with the subjective patient-reported improvement suggests a role for mirabegron as monotherapy in patients who cannot toler­ate antimuscarinics, and might lead to studies of combination therapy in patients with s­ymptoms refractory to either class of drugs alone. 2013 also saw the publication of a clini­ cal trial of intradetrusor injection (100 U) of onabotulinumtoxinA in patients with OAB with idiopathic urgency urinary inconti­ nence (UUI).5 This multicentre, randomized, placebo-controlled trial sought to evaluate the efficacy and risk in this population. The primary efficacy measures at 12 weeks were the changes from baseline inthe dailyaverage frequency of UUI episodes and the propor­ tion of patients with a positive treatment response on a patient-reported outcome scale. Patients were excluded if they were taking antimuscarinic medications for OAB, or if they had a postvoid residual volume of >100 ml at baseline.MeandailyUUIepisodes were markedly decreased for onabotulinum­ toxinA compared with placebo (–2.65 versus –0.87), although 6.1% of patients receiving onabotulinumtoxinA required intermittent catheter­ization (initiated for postvoid resid­ ual volume of 200–350 ml with symptoms, or >350 ml without symptoms) compared with 0% in the placebo group. However, not all participants in the onabotulinumtoxinA arm who met these criteria initiated catheter­ ization, and the majority of patients were catheterized for ≤6 weeks. Overall, onabo­ tulin­um­toxinA shows considerable efficacy and a low risk of needing to c­atheterize in this population. Additionally, the results of a multicentre, randomized trial of physiotherapy versus Macmillan Key advances ■■ The clinical benefits and favourable adverse-effect profile of mirabegron for overactive bladder syndrome (OAB) suggests the drug could be used as monotherapy in these patients2,3 ■■ Intradetrusor injection of onabotulinumtoxinA dramatically decreased incontinence episodes in patients with OAB with idiopathic urgency urinary incontinence (UUI)5 ■■ Objective and patient-reported cure rates were higher for those undergoing midurethral sling surgery than physiotherapy for stress urinary incontinence (SUI), confirming both as viable options and providing evidence for expectation management during shared decision making6 ■■ Urodynamic assessment significantly impacts the clinical diagnosis and the likelihood of additional treatment for urgency incontinence,8 but is not required prior to surgical treatment for demonstrable stress incontinence ■■ Sacrocolpopexy, with or without concomitant Burch urethropexy, for SUI is associated with failure rates that increase over time10 and patients should be monitored for mesh and suture complications © 2014 Macmillan Publishers Limited. All rights reserved
  • 94. 84  |  JANUARY 2014 www.nature.com/reviews UROLOGY PROSTATE CANCER IN 2013 The changing role of imaging in clinical care Rahul Aggarwal and John Kurhanewicz Considerable developments in prostate cancer in 2013 have emerged from the imaging field. Hyperpolarized 13 C-MRI can monitor metabolic activity to identify high-grade disease and treatment response, and novel PET radiotracers might identify distinct subsets of patients with advanced disease. These examples highlight the progress made at all stages of care. Aggarwal, R. & Kurhanewicz, J. Nat. Rev. Urol. 11, 75–77 (2014); published online 14 January 2014; doi:10.1038/nrurol.2013.319 midurethralslingsurgeryforfemaleSUIwere reported in late 2013.6 The primary outcome measure was patient-reported improvement, with secondary outcomes including subjec­ tive and objective cure. The study allowed crossover between arms, which was revealing in that 49% of women in the physiotherapy group crossed over to surgery, whereas 11.2% of patients in the surgery group crossed over to physiotherapy. Not unexpectedly, the improvement and cure rates were signifi­ cantly higher in the surgery group than in the physiotherapy group. In the sling group, 91% of patients reported improvement, with 85% subjectively and 76% objectively cured; for physiotherapy, 64% of patients reported improvement, with 53% subjectively and 59% objectively cured. These results provide a useful tool for counselling patients on the response rates to these SUI treatments. This study also gives insight into complica­ tions arising from mesh suburethral slings. The rate of adverse events in those who received physiotherapy only (no crossover) was essentially zero. By contrast, in the sling surgery group, adverse effects and compli­ cations included bladder perforation (2.8%), vaginal mesh exposure (3.7%), reoperation for exposure of the mesh (2.3%), reoper­ ation to loosen the sling (0.5%) and de novo OAB (6%). These complication rates are similar to other published series and high­ light the safety of synthetic mesh use in sub­urethral slings, in contrast to the contro­ versial use of transvaginal synthetic mesh for POP, which uses larger mesh implants. Secondary analysis from the ValUE trial,7 which showed that outcomes for women undergoing treatment for SUI did not change with the addition of preoperative uro­ dynamic evaluation, were also reported in 2013 by the Urinary Incontinence Treatment Network.8 Researchers showed that uro­ dynamic assess­ment significantly changed the clinical diag­nosis and the likelihood of additional treatment for urgency inconti­ nence postoperatively, but did not change global treatment plan or decision-making to modify or cancel surgery. This finding pro­ vides further support for current guidelines that patients with demonstrable SUI on office evaluation can undergo surgical treatment without urodynamics.9 Finally, long-term data for the use of abdominal sacrocolpopexy as a surgical treatment for POP were presented in a study by the Pelvic Floor Disorders Network.10 The study reported outcomes after a median of 7 years for participants in the CARE (Colpopexy and Urinary Reduction Efforts) trial. The 2‑year CARE trial initially com­ pared sacrocolpopexy with and without concomitant Burch urethropexy for SUI and POP outcomes. The latest report used data fromtheextendedCAREtrialfor126 women (59% of the original cohort). Failure was defined as symptomatic or anato­mical POP failure requiring retreatment, self-reported vaginal bulge or POP quantifi­cation evalu­ ation demonstrating recurrent anatomical prolapse. The estimated composite prob­ ability of failure of abdominal sacrocolpo­ pexy at 7 years was 0.48 and 0.34 for patients with and without concomitant urethro­pexy, respectively—failure rates that increased over time compared with 5‑year POP failure (probability of 0.39 and 0.29 for patients with and without concomitant urethropexy, respectively), indicating that both early and late failures are common. Additionally, the authors reported a symptomatic and exam-detected mesh and suture exposure rate of 9.9% for this population, which also increased over time and is higher than previ­ ously reported for trans­abdominally placed mesh, indicating that close follow-up for signs and symptoms of mesh or suture expo­ sure is as important in this group as it is in patients with transvaginal mesh. Several advances in the treatment of OAB in men and women were actively studied and widely used clinically in 2013 after the pub­ lication of key clinical trials, including mira­ begron treatment. Outcomes for treatments for SUI and POP were scrutinized for oppor­ tunities for improvement. Looking forward, studies in 2014 are likely to investigate how to best integrate these results into clinical guidelines and algorithms and to promote i­nnovationwhereoutcomescanbe improved. Department of Urology, University of Michigan, 1500 East Medical Center Drive, 3875 Taubman Center, SPC 5330, Ann Arbor, MI 48109‑5330, USA (L. Cox, J. Q. Clemens). Correspondence to: J. Q. Clemens qclemens@umich.edu Competing interests The authors declare no competing interests. 1. Abrams, P., Cardozo, L., Khoury, S. & Wein, A. J. (Eds) Incontinence: Fifth Edition 2013 (ICUD‑EAU, 2013). 2. Nitti, V. W. et al. Results of a randomized phase III trial of mirabegron in patients with overactive bladder. J. Urol. 189, 1388–1395 (2013). 3. Khullar, V. et al. Efficacy and tolerability of mirabegron, a β3-adrenoceptor agonist, in patients with overactive bladder: results from a randomised European-Australian phase 3 trial. Eur. Urol. 63, 283–295 (2013). 4. Nitti, V. W. et al. Mirabegron for the treatment of overactive bladder: a prespecified pooled efficacy analysis and pooled safety analysis of three randomised, double-blind, placebo- controlled, phase III studies. Int. J. Clin. Pract. 67, 619–632 (2013). 5. Nitti, V. W. et al. OnabotulinumtoxinA for the treatment of patients with overactive bladder and urinary incontinence: results of a phase 3, randomized, placebo controlled trial. J. Urol. 189, 2186–2193 (2013). 6. Labrie, J. et al. Surgery versus physiotherapy for stress urinary incontinence. N. Engl. J. Med. 369, 1124–1133 (2013). 7. Nager, C. W. et al. A randomized trial of urodynamic testing before stress-incontinence surgery. N. Engl. J. Med. 366, 1987–1997 (2012). 8. Sirls, L. T. et al. The effect of urodynamic testing on clinical diagnosis, treatment plan and outcomes in women undergoing stress urinary incontinence surgery. J. Urol. 189, 204–209 (2013). 9. Dmochowski, R. R. et al. Update of AUA guideline on the surgical management of female stress urinary incontinence. J. Urol. 183, 1906–1914 (2010). 10. Nygaard, I. et al. Long-term outcomes following abdominal sacrocolpopexy for pelvic organ prolapse. JAMA 309, 2016–2024 (2013). Alongside advances in drug development, 2013 has arguably been the year of imag­ ing in prostate cancer. Emerging imaging modalities are now being applied at all points in the disease process—including at initial diagnosis, during active surveillance of © 2014 Macmillan Publishers Limited. All rights reserved
  • 95. KEY ADVANCES IN MEDICINE JANUARY 2014  |  85 UROLOGY localized disease, upon bio­chemical relapse and in metastatic disease—and are likely to considerably shape practice p­atterns in years to come. Current standard practice of diagnosing prostate cancer involves transrectal samp­ ling of 10–14 bilateral cores of prostate cancer tissue. However, a substantial false-­ negative rate is associated with this approach, especial­ly with lesions in the anterior pros­ tate gland. Multiparametric proton-based (1 H) MRI (mpMRI), using T2, diffusion- weighted, dynamic c­ontrast-enhanced and 1 H magnetic resonance spectro­scopic imaging (1 H-MRSI) sequences can address these issues by assessing the entire p­rostate— providing guidance for targeted biopsies. For example, Puech et al.1 examined 95 men with suspected prostate cancer on the basis of a suspicious lesion detected on mpMRI. MRI-targeted biopsies in these men yielded higher rates of cancer, including clinically significant prostate cancer defined by any Gleason ≥4 pattern, than a standard sys­ tematic 12-core ultrasonography-guided biopsy, particularly in the anterior region of the gland.1 Although validation is required in a broader unenriched patient population, as is long-term follow up data to accurately determine false-negative biopsy rate, the use of pre-biopsy mpMRI might eventu­ ally be incorporated into standard diagnos­ tic algorithms to increase the sensiti­vity of this approach to detect clinically s­ignificant high‑grade prostate cancer. For patients with an established prostate cancer diagnosis, avoiding over­treatment of low-risk, clinically insignificant localized prostate cancer has spurred the develop­ ment of active surveillance strat­egies that incorporate serial biopsies and PSA measure­ ment. However, despite gains in popularity, concerns regarding the risk of undetected high-grade disease often prompt patients to opt for definitive treatment in the absence of objective evidence of disease up­staging. Novel genomic predictive biomarkers can improve upon stand­ard clin­ical risk stratifi­cation criteria, but are still prone to sampling error related to the biopsy pro­ cedure.2 Given this limitation, mpMRI might have clinical utility in expanding the number of patients with confirmed low-risk disease who would be appropriate candi­ dates for active surveillance. At the same time, the technique can enhance the ability to detect occult high-grade disease and identify patients who should receive defini­ tive local therapy. One review published in 2013 included 133 patients who underwent mpMRI a median of 60 days before radical prostate­ctomy.3 The researchers showed that mpMRI was better than common clini­ cal scoring systems (D’Amico, Epstein and UCSF–CAPRA) at correctly classifying patients as appropriate for treatment versus active surveillance on the basis of domi­ nant tumour volume, predominant Gleason pattern and extra­capsular or seminal vesicle invasion. Only one of the 13 patients with high-risk pathological disease was classi­fied as low risk on mpMRI. Although prospec­ tive valid­ation is required using a standard­ ized MRI scoring system, and integra­tion of recently validated genomic-based prediction scores is essential, mpMRI has the potential to play a key part in improving the accu­ racy of selecting a­ppropriate candidates for active surveillance. A new molecular imaging MRI technique, hyperpolarized 13 C-MRI, which relies on the detection of carbon nuclei rather than protons, also has the potential to improve cancer diagnosis, risk stratification and, in particular, the monitoring of treatment response. 13 C-MRI provides enhanced spatial and temporal resolution compared with 1 H-MRSI and can be used in the noninvasive real-time assessment of metabolic activity to image cancer. For example, 13 C-pyruvate—a metabolite involved in the synthesis of lactate via aerobic glycolysis, a pathway upregulated in cancerous cells by way of the Warburg effect—can be used across a spectrum of malignancies that includes prostate cancer. In the first ever phase I study of metabolic MRI using 13 C-pyruvate reported in 2013, 31 treatment-naive patients with biopsy- proven localized prostate cancer were enrolled, the majority of whom had Gleason 3 + 3 disease.4 Patients were injected with the 13 C-labelled pyruvate, shortly after which its conversion to lactate could be observed in prostate tumours and, in some cases, in regions of cancer that were not detected by conventional MRI. Although targeted biop­ sies were not mandatory in the study design, one patient with previously diagnosed Gleason 3 + 3 prostate adenocarcinoma with unilateral disease on MRI was shown to have bilateral elevations in the ratio of lactate to pyruvate on 13 C-MRI. This patient’s tumour was sub­sequently upstaged and upgraded, to bilateral Gleason 3 + 4 cancer, on directed 13 C-MRI-guided biopsy. 13 C-MRI of hyper­ polarized pyruvate might, therefore, have a role in detecting occult high-grade disease to aid in treatment selection and prognostic­ ation of patients with localized prostate cancer. Future patient studies are needed to define the utility of this imaging modality in assessing treatment response, and pro­ spective studies will be needed to correlate imaging findings with histological grade at the time of radical prostatectomy. Approximately 25–35% of patients who initially respond to definitive local therapy will experience biochemical relapse. PSA doublin­g time, Gleason grade at time of diagnosis and time interval from definitive therapy to incidence of relapse are used to predict patterns of recurrence (loco­regional versus distant), but there is considerable overlap between these clinical metrics. PET- based imaging might offer a more sensitive Macmillan Key advances ■■ Multiparametric MRI (mpMRI)-targeted biopsies yielded higher rates of prostate cancer detection, including clinically significant (Gleason ≥4) disease, than standard 12-core guided biopsy, demonstrating its potential for improved risk stratification1 ■■ mpMRI performed better than clinical assessment scoring systems in predicting which patients were appropriate active surveillance candidates3 ■■ A phase I trial demonstrated the safety and feasibility of hyperpolarized 13 C-MRI to provide real- time noninvasive assessment of metabolic activity to aid cancer diagnosis, risk stratification and treatment response monitoring4 ■■ Two PET agents—11 C choline and 18 F-NaF—have been shown to have improved sensitivity compared with conventional imaging in detecting lymph node involvement4 and the presence of bone metastases5 ■■ New PET-based molecular imaging approaches have promise as biomarkers in advanced- stage prostate cancer, distinguishing between androgen-receptor‑dependent8,9 and treatment- emergent neuroendocrine prostate cancer10 © 2014 Macmillan Publishers Limited. All rights reserved
  • 96. 86  |  JANUARY 2014 www.nature.com/reviews UROLOGY method of detecting regional disease, distant spread of disease or both than conventional cross-sectional imaging and clinical para­ meters. A 2013 systematic review and meta- ­analysis of 19 independent studies high­ lighted the potential benefit of 11 C-choline PET imaging, demonstrating a favour­ able sensitivity and specificity for detecting recurrent cancer: sensitivity and specific­ ity for detection in the prostatic fossa were 75.4% and 82% and for lymph node metas­ tases were 100% and 81.8%, respectively.5 11 C-choline PET was recently approved at the high-volume Mayo Clinic (Rochester, MN, USA) for the detection of recurrent disease. Additionally, 18 F-NaF PET has demonstrated increased sensitivity for detecting distant osseous metastases compared with conven­ tional 99 Tc bone scanning, including patients with biochemically relapsed disease who are at elevated risk of metastatic disease owing to a rapid rise in serum PSA level.6 Androgen deprivation therapy is the stand­ard of care for patients with recur­ rent or metastatic disease, but all patients eventual­ly develop castration-resistant pros­ tate cancer (CRPC). Considerable molecu­ lar heterogeneity underlies the biology of CRPC, with continued reliance on andro­ gen receptor (AR)-mediated signalling that frequently gives rise to AR‑independent, c‑MYC-driven neuroendocrine prostate cancer (NEPC) as a treatment-emergent adaptive response.7 Although no currently available bio­markers are able to readily identify and predict subsets of patients who are most likely to respond to contin­ ued AR‑directed therapy, new PET-based molecular imaging approaches might offer a suitable alternative and have the potential to accurately distinguish AR‑dependent pros­ tate cancer from treatment-­emergent NEPC. Indeed, 18 F-fluoro‑5α-dihydrotestosterone (18 F-FDHT)-PET was used as a pharmacody­ namic biomarker of AR ligand binding in the early phase clinical trials of the s­econd-gen­ erationARantagonistsARN‑509andenzalu­ tamide, and helped guide the recom­mended phase II dose selection of these two agents.8 Emerging molecular probes aim to extend the capability of PET imaging to measure downstream AR transcriptional activ­ ity. In 2013, one such probe was reported; 89 Zr‑J591/PSMA, a radio­labelled prostate membrane specific antigen (PSMA) probe, was shown to be inversely related to AR transcriptional activity.9 In another example, detection of treatment-emergent NEPC driven by c‑MYC was enhanced with the use of 89 Zr-transferrin, which binds to the transferrin receptor—a direct transcriptional target of c‑MYC. Preclinical studies have demonstrated the feasibility of this approach, and results of the initial clinical studies are eagerly awaited.10 Finally, the advantages of MRI and PET imaging of prostate cancer are being merged with the develop­ment of clini­ cal PET–MRI instruments, which will facili­ tate a more-comprehensive metabolic and functional characterization of both localized and m­etastatic disease.8 In 2013, key advances in the application of imaging were reported across the spectrum of clinical disease states in prostate cancer. Looking forward, prospectively validating imaging technologies, ideally with concur­ rent integration of emerging genomic and molecular analyses, will help to further define the role of imaging in the clinical care of men with prostate cancer. Department of Medicine, Division of Hematology/Oncology, University of California San Francisco, 1600 Divasadero Street, Room A717, Box 1711, San Francisco, CA 94115, USA (R.Aggarwal). Departments of Medicine and Radiology and Biomedical Imaging, University of California, San Francisco, 1700 4th Street, Byers Hall, Room 203, San Francisco, CA 94158, USA (J. Kurhanewicz). Correspondence to: J. Kurhanewicz john.kurhanewicz@radiology.ucsf.edu Competing interests The authors declare no competing interests. 1. Puech, P. et al. Prostate cancer diagnosis: multiparametric MR‑targeted biopsy with cognitive and transrectal US‑MR fusion guidance versus systematic biopsy--prospective multicenter study. Radiology 268, 461–469 (2013). 2. Cooperberg, M. R. et al. Validation of a cell- cycle progression gene panel to improve risk stratification in a contemporary prostatectomy cohort. J. Clin. Oncol. 31, 1428–1434 (2013). 3. Turkbey, B. et al. Prostate cancer: can multiparametric MR imaging help identify patients who are candidates for active surveillance? Radiology 268, 144–152 (2013). 4. Nelson, S. J. et al. Metabolic imaging of patients with prostate cancer using hyperpolarized [1‑13 C]pyruvate. Sci.Transl. Med. 5, 198ra108 (2013). 5. Evangelista, L. et al. Choline PET or PET/CT and biochemical relapse of prostate cancer: a systematic review and meta-analysis. Clin. Nucl. Med. 38, 305–314 (2013). 6. Beheshti, M., Langsteger, W. & Fogelman, I. Prostate cancer: role of SPECT and PET in imaging bone metastases. Semin. Nucl. Med. 39, 396–407 (2009). 7. Mosquera, J. M. et al. Concurrent AURKA and MYCN gene amplifications are harbingers of lethal treatment-related neuroendocrine prostate cancer. Neoplasia 15, 1–10 (2013). 8. Jadvar, H. Molecular imaging of prostate cancer with PET. J. Nucl. Med. 54, 1685–1688 (2013). 9. Osborne, J. R. et al. A prospective pilot study of 89Zr‑J591/PSMA positron emission tomography (PET) in men with localized prostate cancer undergoing radical prostatectomy. J. Urol. http://dx.doi.org/ 10.1016/j.juro.2013.10.041. 10. Walia, G., Pienta, K. J., Simons, J. W. & Soule, H. R. The 19th annual Prostate Cancer Foundation scientific retreat. Cancer Res. 73, 4988–4991 (2013). KIDNEY CANCER IN 2013 From molecular understanding to clinical advances Chung-Han Lee and Robert J. Motzer Big data and computational biology brought to the forefront a number of potential actionable mutations and drug targets in clear cell renal cell carcinoma in 2013. As we continue to unravel the molecular underpinnings of tumorigenesis and progression, the clinical benefits will eventually be reaped. Lee, C.‑H. & Motzer, R. J. Nat. Rev. Urol. 11, 77–79 (2014); published online 24 December 2013; doi:10.1038/nrurol.2013.307 2013 marked a year in which important insights were gained in kidney cancer, from treatment of the disease to its under­ lying biology. Pazopanib and sunitinib are vascu­lar endothelial growth factor receptor (VEGFR)-targeted receptor tyrosine kinase inhibitors (TKIs) directed selectively toward VEGFR‑2. TKIs often have off-target effects on related kinases, and in vitro screening of panels of kinases suggests that pazopanib has fewer off-target interactions than suni­ tinib.1 These drugs were approved for use in the first-line setting in metastatic clear cell renal cell carcinoma (ccRCC) on the basis of comparisons with placebo and IFN‑α, respectively. In 2013, a large randomized phase III trial (COMPARZ; NCT00720941) compared the two drugs head to head in the first-line setting.2 The trial met its primary end point of independently assessed © 2014 Macmillan Publishers Limited. All rights reserved
  • 97. KEY ADVANCES IN MEDICINE JANUARY 2014  |  87 UROLOGY progression-­free survival (PFS), and showed that pazopanib was noninferior to sunitinib with respect to PFS (hazard ratio [HR] 1.05; 95% CI 0.90–1.22). Overall, the COMPARZ results indicate that pazopanib and suni­ tinib have similar efficacies, but pazopanib has better overall safety and adverse effects profiles (including fatigue and blood count suppression advantages) and is associ­ ated with superior quality of life; however, pazopanib was associated with a greater incidence of liver enzyme elevation. The superior safety profile of pazopanib might be attributable to its increased selectivity for VEGFR‑2, although definitive evidence supporting this hypothesis is needed. Given the equivalent efficacy of these treatments, first-line therapy can now be personalized to each patient’s particular tolerance. In addition to this major finding in the clinical management of patients with ccRCC, 2013 was an exciting year in kidney cancer basic research, which drives discov­ eries into tumorigenesis and might ulti­ mately lead to the identification of novel targets for therapy. Findings from The Cancer Genome Atlas (TCGA) marked the completion of an ambitious project to molecularly characterize and catalogue ccRCC.3 Patient-derived tumour samples were analysed on multiple platforms that included assays for somatic alterations, DNA methylation and RNA expression, identifying 19 significantly mutated genes, including epigenetic chromatin remodelling agents, such as SETD2, PBRM1, ARID1A and SMARCA4.3 Global promoter hyper­ methylation, which leads to gene silenc­ ing, is also correlated with high stage and grade in ccRCC. In addition, the correlation of RNA expression profiling with survival character­istics highlighted the import­ ance of metabolic pathways in ccRCC. Poor survival was shown to be correlated with a metabolic shift that downregulates genes involved in the tricarboxylic acid (TCA) cycle and upregulates genes of the pentose phosphate pathway and glutamine transport, although the exact genomic and epigenetic mechanisms that lead to these changes in RNA expression are not yet understood.3 This metabolic shift sug­ gests that ccRCC is a model cancer for the Warburg effect,4 whereby cancers rely predominantly on glycolysis as their energy source. These data also suggest that glutamine is a key metabolite in ccRCC patho­genesis, but further metabolomic assessment of ccRCC is necessary to fully understand the mechanisms at play. The metabolic characteristics of ccRCC suggested by TCGA were further supported by other basic research published in 2013, investigating the crucial roles of glutamine metabolism and epigenetic modification in ccRCC. One study showed that hypoxia inducible factor (HIF) drives glutamine dependence in ccRCC;5 elevated HIF is a direct result of loss of the Von Hippel– Lindau tumour suppressor (encoded by VHL)—the most common mutation in ccRCC.3 In the presence of elevated HIF, glutamine becomes a critical energy source for lipid anabolism by reductive carboxy­ lation,5 which is a mechanism implemented to reverse the TCA cycle to produce citrate from α‑ketoglutarate without requiring acetyl-­CoA from glycolysis (Figure 1).6 Loss of VHL induces a glutamine-dependent phenotype whereby cell proliferation can be inhibited by glutamine withdrawal or treat­ ment with inhibitors of glutamine metabo­ lism. As shown by studies in cell lines, this phenotype can be rescued by reintro­ duction of VHL or supplementation of cell-­ permeable glutamine catabolites, which bypass the pharmacologically induced defects in metabolism.5 Treatment of ccRCC xenograft mice models with BPTES, a gluta­ mate dehydrogenase inhibitor that acts at a critical step in the metabolism of glutamine to lipids, also inhibited tumour growth.5 Given the correlation between upregula­ tion of glutamine transporters and worse survival identified by TCGA,3 inhibitors of glutamine metabolism might be poten­ tial drug candidates for exploration, which would be novel in ccRCC. Additionally, understanding the interplay between gluta­ mine metabolism and the genetic landscape of ccRCC might identify subsets of patients who would derive the most benefit from inhibitors of glutamine metabolism. Another report in 2013 from TCGA suggests that ccRCC is a disease of epi­ genetic modification, particularly in terms of driving metastasis.7 Although VHL loss is the most common mutation in ccRCC, it is insufficient on its own to drive t­umorigenesis—additional genetic ‘hits’ are necessary to promote patho­genesis. Data from TCGA showed that epi­genetic modifiers, such as PBRM1, SETD2 and BAP1 (which are all involved in chroma­ tin remodel­ling) are the most common mutations in ccRCC after VHL. However, Figure 1 | VHL loss induces reductive carboxylation. Under oxygen-rich conditions, normal cells synthesize fatty acids through glucose-derived citrate. By contrast, under hypoxic or pseudohypoxic conditions—such as HIF accumulation through loss of VHL—ccRCC synthesizes fatty acids through glutamine-derived citrate. Abbreviations: ccRCC, clear cell renal cell carcinoma; HIF, hypoxia-inducible factor; TCA, tricarboxylic acid. TCA cycle Succinate Fumarate Malate Oxaloacetate α-Ketoglutarate Succinyl-CoA Isocitrate Citrate Acetyl-CoALactate PyruvateGlucose Glutamate Glutamine Oxaloacetate Acetyl-CoA Fatty acids BPTES Normoxia Hypoxia or pseudohypoxia cis-Aconitate © 2014 Macmillan Publishers Limited. All rights reserved
  • 98. 88  |  JANUARY 2014 www.nature.com/reviews UROLOGY how mutations in these genes contribute to ccRCC pathogenesis remains poorly understood, especially as only rare clones are capable of rapidly seeding metastases (as illustrated by the fact that injection of the parental cell-line population into nude mice typically results in only local tumour for­ mation).7 In their study, Vanharanta et al.7 isolated subpopulations of cancer cells from a cell line originally derived from a patient with widely metastatic disease, and found that the metastatic potential of such cells was variable. In fact, they determined that altered expression of VHL–HIF targets was associated with metastasis. Gene expression profiling identified the chemokine (C‑X-C motif) receptor 4 gene—CXCR4—as the most upregulated gene in the metastatic ccRCC clones. CXCR4 expression is HIF‑2- dependent and, although VHL loss is suffi­ cient to induce accumulation of HIF‑2, the transcriptional output of HIF‑2 accumula­ tion is variable. In metastatic cells, a decrease in the repressive mark at histone 3 lysine 27 (H3K27me3) occurs near the CXCR4 locus, which in turn increases CXCR4 expression and enhances the metastatic potential of the cells, an event correlated with poor survival. These data facilitate our understanding of the changes in ccRCC that induce tumour progression. Indeed, with the high preva­ lence of mutations in chromatin remodel­ ling proteins, agents that induce significant changes in gene expression might have dramatic effects on pathogenesis; whether these alterations induce viable drug targets in ccRCC remains to be seen. Overall, kidney cancer research benefited greatly from the global trend of big data and computational biology in 2013. Indeed, these studies generated many attractive hypotheses that warrant further investiga­ tion. We will now be able to leverage our expanding knowledge to diversify our cache of available targets and agents for the treat­ ment of patients with kidney cancer, which is the ultimate goal. Genito-urinary Oncology Service, Department of Medicine, Memorial Sloan–Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA (C.‑H. Lee, R. J. Motzer). Correspondence to: R. J. Motzer motzerr@mskcc.org Competing interests R. J. Motzer declares associations with the following companies: Genentech, GlaxoSmithKline, Pfizer and Novartis. See the article online for full details of the relationships. C.‑H. Lee declares no competing interests. 1. Kumar, R. et al. Myelosuppression and kinase selectivity of multikinase angiogenesis inhibitors. Br. J. Cancer 101, 1717–1723 (2009). 2. Motzer, R. J. et al. Pazopanib versus sunitinib in metastatic renal-cell carcinoma. N. Engl. J. Med. 369, 722–731 (2013). 3. Cancer Genome Atlas Research Network. Comprehensive molecular characterization of clear cell renal cell carcinoma. Nature 499, 43–49 (2013). 4. Linehan, W. M., Srinivasan, R. & Schmidt, L. S. The genetic basis of kidney cancer: a metabolic disease. Nat. Rev. Urol. 7, 277–285 (2010). 5. Gameiro, P. A. et al. In vivo HIF-mediated reductive carboxylation is regulated by citrate levels and sensitizes VHL-deficient cells to glutamine deprivation. Cell. Metab. 17, 372–385 (2013). 6. Wise, D. R. et al. Hypoxia promotes isocitrate dehydrogenase-dependent carboxylation of alpha-ketoglutarate to citrate to support cell growth and viability. Proc. Natl Acad. Sci. USA 108, 19611–19616 (2011). 7. Vanharanta, S. et al. Epigenetic expansion of VHL–HIF signal output drives multiorgan metastasis in renal cancer. Nat. Med. 19, 50–56 (2013). Key advances ■■ From the clinical perspective, pazopanib emerged as the preferred first-line treatment for metastatic clear cell renal cell carcinoma (ccRCC) with publication of the COMPARZ data2 ■■ ccRCC emerged as a model of the Warburg effect, with metabolic patterns showing downregulation of the tricarboxylic acid cycle and upregulation of glutamine transport, glycolysis and pentose phosphate shunt3,5 ■■ Metastatic cells display an increase in CXCR4 expression, which was shown to enhance the metastatic potential of the cells, and correlate with poor survival7 © 2014 Macmillan Publishers Limited. All rights reserved
  • 99. Editors’ picks of the year Transperineal biopsy of the prostate—is this the future? Dwayne T. S. Chang, Benjamin Challacombe and Nathan Lawrentschuk Transperineal prostate biopsy is re-emerging after decades of being an underused alternative to transrectal biopsy guided by transrectal ultrasonography (TRUS). The authors describe the evolution of both the prostate biopsy techniques, focusing on the clinical implications of the transperineal approach and the potential future directions for prostate biopsy. doi:10.1038/nrurol.2013.195 Proteomic studies of urinary biomarkers for prostate, bladder and kidney cancers Steven L. Wood, Margaret A. Knowles, Douglas Thompson, Peter J. Selby and Rosamonde E. Banks In this Review, Wood and colleagues discuss the use of urine as a source of biomarkers and outline the main proteomic methods that are used to identify biomarkers in urine. Preliminary studies that have been performed to identify potential biomarkers of prostate cancer, bladder cancer and renal cell carcinoma are discussed. doi:10.1038/nrurol.2013.24 Surgical management of female SUI: is there a gold standard? Ashley Cox, Sender Herschorn and Livia Lee The high prevalence of SUI has led to the development of several surgical treatment options, but which one is the gold standard? Here, the authors discuss the available evidence in an attempt to answer this question. They also discuss the options for mixed urinary incontinence, intrinsic sphincter deficiency and recurrent SUI. doi:10.1038/nrurol.2012.243 Adaptation or selection—mechanisms of castration-resistant prostate cancer Yang Zong and Andrew S. Goldstein Men with prostate cancer often respond to androgen-deprivation therapy only to later relapse and develop lethal castration-resistant disease. Two models—adaptation and selection—have been described to explain how the disease progresses to this stage. In this Review, the authors describe each model and show that both models might contribute to advanced prostate cancer. doi:10.1038/nrurol.2012.237 Urological aspects of HIV and AIDS Chris F. Heyns, Shaun G. Smit, André van der Merwe and Amir D. Zarrabi In this Review, Heyns et al. provide an update on the urological complications associated with HIV and AIDS in men treated during the ART era, focusing on papers published within the past decade. doi:10.1038/nrurol.2013.230 Risk stratification in prostate cancer screening Monique J. Roobol and Sigrid V. Carlsson Screening for prostate cancer is a controversial topic within the field of urology. Instead of adopting a ‘one size fits all’ approach, physicians are likely to perform personalized risk assessment to minimize the risk of negative consequences, such as anxiety, unnecessary testing and biopsies, overdiagnosis, and overtreatment. In this Review, Monique J. Roobol and Sigrid J. Carlsson focus on the effects of shifts in attitude towards PSA testing on risk stratification. doi:10.1038/nrurol.2012.225 BCG immunotherapy for bladder cancer—the effects of substrain differences Christine Gan, Hugh Mostafid, Muhammad Shamim Khan and David J. M. Lewis BCG is not a defined strain but a family of regional substrains with marked genetic differences. In this Review, the authors discuss the mechanisms by which BCG immunotherapy induces its antitumour activity and treatment- limiting toxicity, and the effect that genetic and phenotypic differences between BCG substrains might have on these effects. doi:10.1038/nrurol.2013.194 Mild to moderate postnatal hydronephrosis—grading systems and management Matthew D. Timberlake and C. D. Anthony Herndon No universal guidelines exist for the management of patients with mild to moderate antenatal hydronephrosis (ANH). In this Review, the authors assess the data and present their own approach to postnatal risk stratification and management, including recommendations regarding serial ultrasonography schedule, prophylactic antibiotics, voiding cystourethrogram and renal scintigraphy. doi:10.1038/nrurol.2013.172 Contemporary diagnostic work-up of testicular germ cell tumours Klaus-Peter Dieckmann, Ulrich Frey and Guntram Lock Any mass discovered in the testicle might be cancerous and, therefore, every effort must be made to characterize the lesion. This Review highlights modern aspects of clinical examination, the modalities for scrotal imaging, and the surgical techniques used for exploring the testis. doi:10.1038/nrurol.2013.254 Overview of the latest treatments for castration-resistant prostate cancer Mohamed Bishr & Fred Saad In this Review, Saad and Bishr present an overview of the different management approaches for patients with CRPC, paying particular attention to recently approved agents and therapies that have shown promising results in phase III trials. doi:10.1038/nrurol.2013.137 February 2014 volume 11 no. 2 www.nature.com/reviews LANDMARKS IN BPH Highlighting the pivotal advances in BPH from the 19th century to present day Infection and urosepsis after prostate biopsy Prevention strategies UROLOGY nrurol_OFC_FEB14.indd 1 23/01/2014 15:38 * * * * * * * * * * A selection of articles published during 2013 in Nature Reviews Urology: Don’t miss out! Sign up to free e-ALERTS and be notified when new articles are published in Nature Reviews Urology. Research Highlights, News & Views, Reviews, and Perspectives—you won’t miss a thing! http://www.nature.com/register © 2014 Macmillan Publishers Limited. All rights reserved