ETS education course“Omics for beginners”paramount importance in reproductive toxicology researchtoxicogenomic and metabolomic data as well as bioinformatics isexpected to play an increasing role for reaching the ultimate goalof chemical safety for man Currently, there are 10,000 to 30,000 chemicals in world-wide commerce in need of hazard data for assessing potential reproductive toxicity health risks. The traditional animal study designs cannot accommodate the evaluation of this large number of chemicals and bioinformatics technologies are currently being developed to make the goal of chemical safety for man reachable.
I. Exploiting the Revolution: Mouse Genetic and Genomic Resources for Reproductive Health Research . Dr. Lee B. Smith - MRC, Edinburgh U.K
II. Toxicogenomic Approaches used in Developmental Toxicology Dr. Joshua F. Robinson - RIVM, The Netherlands
III. MetabolomicsDr. Elwin.R. Verheij - TNO, Zeist, The Netherlands
IV. HTS and Computational Modeling for Developmental Toxicity Dr. Thomas B. Knudsen - USEPA Research Triangle Park, NC, USA
ETS symposium 1 - maternal and childhood asthma: causes, consequences and treatmentAsthma, asthma medications and their effects on maternal/fetal outcome during pregnancy Rocklin RE Asthma: Chronic inflammatory disease of lower airway Bronchial obstruction Symptom: wheezing, shortness of breath, chest tightness, cough Inflammation: 특이 싸이토카인( IL-4, IL-5, IL-13)을 내는 Type 2 helper T cells에 의해서 가속됨. 이들 싸이토카인이 airway에 염증세포들(eosinophils, neutrophils 등)을 chronic infiltration시킴 Prevalence : 4-8% in USA
Effect of pregnancy on maternal asthma Increased estrogen Increased pregesterone B2-adrenoreceptor hypo-responsiveness Female fetus Altered immune function1/3 악화 1/3 변화 없음 1/3 호전
Effects of maternal asthma on pregnancy and perinatal outcomes Lung inflammation Maternal hypoxia Altered placental function Fetal gender Asthma exacerbations Low birth weight Preterm labor Preeclampsia C/S
Reproductive issues in the development of asthma medications Tx goal: maintain control of asthma for maternal health and quality of life as well as normal fetal maturation I. Inflammation control : inhaled corticosteroid, leukotrien inhibitors, chromones II. Relieve sx : B2-agonist theophylline
Anti asthma medications의 development에 고려점 I. Toxic considerations : adverse fetal outcome Route of administration Metabolism Dose Whether the agent crosses the placenta at the point of development at the time of exposure Pharmacologic activity Non-target mediated effects Binding affinity to target in relation to inactive or active forms of the receptors Toxicokinetics II. VLA4 antagonism as a specific example of issues related to asthma drug development
Risk evaluation associated with asthma medication use during pregnancy1. General considerations : Risk and benefit of asthma medication2. Human data : RCT, generally not feasible Case-control study, Cohort study Do not by themselves prove causality Often limited by inadequate sample size 3. Animal data : Animal developmental toxicology experiments Designed to maximize the potential toxic effects by using large dose Negative result: a low potential for human development toxicity Positive result: less predictive for human toxicity (species difference, clinically irrelevant high dose, maternal toxicity?)
Drug label categories and step therapy recommendations단점: paucity of adequate and well controlled data in human Over reliance on animal data Clinical interpretation of C is very difficult Route of administration와 임싞중일어나는 약물의 약동학과 약력학을 고려하지 않음 Inhaled corticosteroid(budesonide) : B
ACAAI-ACOG recommendations for pharmacological step for chronic asthma during pregnancy- 임싞 시 사용될 수 있는 약: inhaled corticosteroids, theophylline, cromolyn, long acting b2 agonist, leukotriene antagonist(monterukast, zafirlukast)- Oral steroid: maintain on lowest effective daily dose of steroid
Safety of asthma medication during pregnancy T4
Maternal and childhood asthma: Risk factors, interactions, and ramifications Dietert RRFetal and early neonatal development: critical period“Barker Hypotheisis”: Prenatal environmental determination of Later life diseasRecent examples of early life environmental determinations1. Developmental Pb on specific childhood neurobehavior outcomes2. Fetal alcohol on CNS3. Developmental PCBs(polycyclic chlorinated biphenys) on adult pregnancy4. Arsenic and resistance to infectious disease5. Prenatal stress on the HPA axis6. Undernutrition and cardiovascular diseas7. Pesticides and neurodegenerative conditions8. Developmental estrogens and risk of prostate cancer9. Developmental high fat intake and liver disease10. Low vitamin D level and GI tr allergy
Maternal and childhood asthma - Risk factorsMaternal asthma: potential implications A family history of atopy and asthma: inheritance of allelles driving Th3-bias and skewed inflammatory responses not pure due to 1. epigenetic alterations-several generations 2. environmental risk factors-differential effects Asthma management in pregnancy : err Th-2 biased environment : exacerbate sx of Th2-associated disease
Immune dysfunction based-disease and childhood¼ of children : immune dysfunction based conditions(asthma, autoimmune ds, inflammatory conditions)Childhood asthma : 선진국에서 최근 크게 증가Childhood asthma : 25.9%
Risk factors for the child “largely developmental disease” : its origin in early life Genetic factors- alleleic and epigenetic alleric varients of gene encoding cytokines, cytokine receptors 등 in animal model, specific genotypes: predispose for Th2-biased adaptive immune responses & hyperinflammatory response in tissue genes involved : related to immune, inflammatory signaling and/or functional response examples: minor allelle of Nrf2, common allele for IL-13 IL-1 receptor like 1 polymorphisms, NOD1 and NOD2 alleles for both TLR-2 and TLR-4 – traffic related air pollutants Interactions between genetic and environmental factors: maternal and child polymorphism for antioxidant status vs prenatal paracetamol(acetaminophen) – affected risk for asthma Study of epigenetics and potential transgenerational effects : infancy
Safety testing gap for childhood asthmaAsthma : most common chronic condition of children greatest number of school absence for chronic disease 입원 치료의 3번째 원인 Annual cost : 18 billion dollarsImmunotoxicity safety testing for childhood allergy and asthma: Not routine for most drugs and chemicals “Safety testing gap”Outcome of the gap: most children must be treated for childhood asthma rather than benefiting from an aggressive safety testing program to prevent childhood asthma one solution: same level of attention for drug development
Endpoints to monitor the management of childhood allergy and asthma : 천식의 위험을 스크린 하는데 유용 levels of IgE antibody, T2 cytokines, eosinophils in bronchial lavage,production of inflammatory mediators, chemokine in the airways,alterations in pattern recognition receptors, changes in bronchial reactivitiyand architectiure 스크린이 효율적이기 위해서 1. age-relevant immunotoxicity safety screening be widely employed in evaluating the safety of drugs and chemicals. 2. Immune respiratory challenge (eq. respiratory viral infection) 포함되어야 함.
Consequence for children diagnosed with asthmaChildhood asthma: a significant lifelong health burden beginning in children and entryway to potential additional chronic diseaseChild with asthma is a high risk group for later childhood andadult onset conditions: allergic rhinitis, atopic dermatitis, otitismedia, increased respiratory infections, behavioral disorders, obesity,olfactory disorders, and lung cancerThe elevated risks be connected to fundamentalimmune dysfunction associated with childhood asthma:Th2 biased responses, improper innate immunematuration, improperly regulated inflammation in theairways, other tissues than can affect metabolism and riskof lung cancer, cytokine imbalances that can affect sleelppatterns, moods and sensory functions
ETS symposium 2 – Prenatal and postnatal causes for obesity and their complications later in life Asher Ornoy PGDM & GDM : Sp abortion, IUFD, congenital anomalies, neurodevelopmental problems, increased risk of perinatal complications 또핚, fetal growth disturbance: increased or decreased BW.
Optimal control of maternal blood glucose: reduce these changesMetabolic syndrome: hypertension, cardiovascular complications, type 2 diabetesExcessive maternal overweight and obesity or excessive wt gain: Increased obesity and complications in the offspring. FGR and Macrosomia : “metabolic syndrome”
Mechanisms underlying these long term effects on growth: Insulin resistance, fetal hyperleptinemia, hypothalamic changes, probably epigenetic changesPrevention of metabolc syndrome: Tight dietary control and physical activity in the children born to obese or diabetic mothers
Long-term effects of FGR and of Macrosomia- the metabolic syndrome Reaven(1988) : Insulin resistance and secondary hyperinsulinemia – etioology of diabetes type 2, cardiovascular disease, hypertension - 3 components of main complications of FGR and macrosomia at adulthood - then called “ syndrome X, later modified to the “metabolic syndrome” - glucose intolerance, increased insulin secretion, increased blood triglyceride, decreased HDL, hypercholesterolemia, cardiovascular disease, diabetes type 2
Thrifty phenotype hypothesis: - epidemiological association between poor fetal growth, type 2 diabetes, metabolic syndrome result from the effects of poor nutrition in early life, which produces permanent changes in glucose insulin metabolism reduced capacity for insulin secretion and insulin resistance obesity, aging and physical inactivity : cardiovascular and metabolic complications the result of adaptational change of the fetal endocrine-metabolic mechanism to the impaired intrauterine milieu to assure survival in the short term
FGR이 일어났던 time과 정도에 따라, 각 개인들에서metabolic syndrome의 parameter가 다르게 나타남 : Symmetric type of FGR : arterial hypertension later in life Asymmetric type of FGR : glucose intolerance and type 2 diabetes.GDM and Obesity associated macrosomia : strong predictor of metabolic syndrome
Mechanisms of long term outcome of children born SGA ormacrosomic1) The “Thrifty” genes or “Barker” hypothesis(metabolic syndrome)2) Insulin resistance3) Changes in leptin secretion and leptin insensitivity4) Hypothalamic programming5) Epigenetic changes
1) The “Thrifty” genes or “Barker” hypothesis(metabolic syndrome)-“thrifty phenotype” hypothesis : Hales and Barker 1992 407 men Hertfordshire, England 1920-1930 226 men and women Preston, England 1935-1943 Size at birth and 1year of age Prevalence of “thrifty syndrome” fell progressively in both men and women with the increase in birth weight At birth, subjects with the thrifty syndrome : small head circumference, at 1year low weight and below-average dental eruption. Type 2 diabetes and hypertension : common origin in sub- optimal growth and development in in utero
2. Insulin resistanceInsulin resistance : fundamental and most important underlying problem inthe pathogenesis of the “metabolic syndrome”Insulin resistance cause insulin over-secretion followed by insulin deficiency,which is the basic pathogenesis of obesity and type 2 diabetesIn pregnant women with GDM, maternal hyperglycemia(diabetes) induces fetalhyperinsulinemia.Elevated fetal insulin affect its hypothalamic development.Insulin in the brain decrease food intake, while insulin depletion(or resitance)may promote hyperphagia.Fetal intra-cerebral injection of insulin : decline of the NPY(Neuropeptide Y)protein, NPY increase food intake.These effects on the fetal brain : long lasting, affecting hypothalamicorganization and metabolism.Increased insulin levels increase leptin secretion by adipocytes, furtherdecreasing food intake.
3) Changes in leptin secretion and leptin insensitivityLeptin : hormone secreted by the adipose tissue which acts as a sensor of body fats. Secteted in levels that directly correlate with body fat stores Acts as an anorexogenic hormone in the brain Controlling feeding behavior by specifically decreeing appetite Leptin or leptin receptor animal or man : early onset obesity Main action : in the hypothalamus hypothalamus arcuate nucleus’ neuron : express several peptides related to feeding behavior
“leptin resistance” : situation where leptin is elevated in the blood of obese individual occur in many obese people where food intake is not reduce in spite of the increased leptin levels different explanation: impaired transport through the BBB, impairment of leptin signaling by the chronic high level of leptinPlacenta produces a significant amount of leptinInsulin treatment increase the production of leptin by the placenta, as afetal cerculating leptinFetal hyperleptinemia(by maternal obesity or maternal increased wt gain) : significnat influence on the fetal hypothalamus and on future energy homeostasisMice lacking leptin : increased appatite, obese and become diabetic due to development of insulin resistance
4) Hypothalamic programming : the role of fetal nutritional imbalance Hypothalamus : regulate food intake and energy balance Different area for the regulation : ventromedial hypothalamic nucleus : satiety lateral hypothalamic area : feeding center In these area, neurotransmitters(norepinephrine, serotonin, GABA ext) are secreted. 이들 neurotransmitter의 metabolism의 변화는 food intake에 영향 Most important area : arcuate nucleus- have both central and peripheral connections also containing leptin sensitive neuron. NYP : a 36 amino acid peptide released from the nerve terminals of the arcuate nucleus and in other part of cerebral cortex. involve in vasomotor reactivity, sexual function, promote feeding and obesity
POMC(proopiomelanocortin derived peptides) : inhibit feeding glycoprotein which serves as multihormonal precursor of corticotropin, lipotropins, melanotropins, dendorphinsThe neurons secreting NPY of POMC have synapses with neurons locatedin other parts of the hypothalamus associated food regulations, also withneurons in the cerebral cortex, thalamus and brain stem.Receive information from the periphery mainly through leptin and insulin.Nutritional change of developing fetus( resulting in FGR or macrosmoia)will induce long lasting changes in the hypothalamic centers that controlfood intake.Most hypothalamic connections in the human fetus seem to developduring the second half of pregnancyHypothalamic disturbances may cause obesity and diabetes
5) Epigenetic changesHow do intrauterine growth disturbances remain as a stable memory in the later biology and behavior of the offspring?New understanding of genome-function is emerging.Genome-functionality is determined by DNA sequence, thetiming and expression of the genes.Epigenome: molecular mechanisms that govern geneexpression in a time- and cell-type dependant fashion.Early environmental exposures such as high glucose ormaternal obesity and overfeeding during pregnancy alter theprogramming of genes by epigenetic markings, resulting in along term imprint on gene expression that lasts into adulthood.
Severe reprogramming of critical genes for development may result interatogenicity or early neurodevelopmental deficit,Whereas responses in the physiological range would increase the risk ofdevelopment of neurobehavioral problems, obesity and thye 2 diabeteslater in life.Homeobox PdX1 undergoes progressive epigenetic silencing in beta cellsin rodents that were exposed to intrauterine growth retardation and areprone to develop diabetes.Streptozocin induced type 1 diabetes in the rat results in genral DNAhypomethylation in the liver.Gluckman and Hanson: fetal undernutrition causes epigenetic changes thatcan later in life, when nutrition is adequate or high, cause metabolicimbalance resulting in the typical “metabolic syndrome”Stevens : maternal undernutrition may induce epigenetic changes in theoffspring, especially in the hypothalamic neuropeptide(NPY, POMC) genesthat regulate energy balance.One of the most important tasks of preventive medicine in the 21st century
ETS-T Debate- “All Mixed up about Mixtures: How Big of a problem and What to Do about it” Teratology society : low level of mixtures is OK European teratology society : sensitive endpoints of antiandrogen 1. anogenital distance 2. nipple retention 3. malformation : hyposphadia 0% + 0% + 0% = ~60% “Paracelsus” : dose make poison so, cumulative dose make risk.
Elsevier Award lecture :Fetal malformations and early embryonic gene expressionresponse in Cynomolgus monkeys maternally exposed tothalidomide Makoto Ema
ETS Award lecture “The Male conundrum” John TeshConundrum : confusionBC 600, 피타고라스 : male essence for offsprings 아리스토텔레스 : Theory of epigenesis Soul guide gradual epigenetic development - - -1993, Male mediated developmental toxicity Male Female Offsprings
Free Communications In utero exposure to antiepileptic drugs: Cognitive development and functioning of the child University of Manchester, UK Epilepsy : 198 Control 210 Sodium valproate (n=51) : lower global cognitive ability, memory, attention, rate of learning, language score Dose dependent relationship was found, above 800mg/d increased cognitive impairment. Neurodevelopmental disorders of valproate vs control : OR 7.28 No significant association with lower cognitive or neurodevelopmental disorders was founded born to women with untreated epilepsy(n=25) , carbamazepine(n=50), lamotrigine(n=29)