ACE2: From Renoprotection to a Potential
Therapy for Coronavirus Infection
ACE2: From Renoprotection to a Potential
Therapy for Coronavirus Infection
by Daniel Batlle MD
RAS Inhibitors in Hypertension and Heart Failure:
TRUTHS AND MISTRUTHS
OF TREATMENT IN THE
COVID-19 ERA
by J o r d y C o h e n , M D , M S C E
From Hypertension 2020 , American Heart Association
Copy RIght to Hypertension Session 2020 in American Heart Association
1. ACE2: From Renoprotection to a Potential
Therapy for Coronavirus Infection
Daniel Batlle MD
Earle, del Greco
Levin Professor of Medicine
Division of Nephrology and Hypertension
Northwestern University Feinberg School of Medicine
Chicago IL
2. DISCLOSURES
• Dr. Batlle is a co-inventor of a patent entitled ‘Active Low Molecular
Weight Variants of Angiotensin Converting Enzyme 2’ and has submitted
patent applications on ‘’Novel ACE2 proteins for coronavirus
infection” and ‘’Active low molecular weight variant of Angiotensin
Converting Enzyme 2 for the treatment of diseases and conditions of the
eye ’’
• Dr. Batlle is Founder and majority shareholder of ‘Angiotensin
Therapeutics Inc’.
• Dr. Batlle has received consultant fees from Relypsa , Tricida and Astra
Zeneca.
3. 3
Before…
After…
Modified from Danser , Epstein and Batlle Hypertension 2020
ACE2: From Renoprotection to a Potential Therapy for Coronavirus Infection
4. What is ACE2 ?
• Angiotensin Converting Enzyme II is a
monocarboxypepetidase that hydrolyzesAngiotensin
II and other peptides.
• The name ofACE2 was given when it was discovered
in 2000 because of considerable homology with
Angiotensin Converting Enzyme (ACE) ( 61%
homology)
• UnlikeACE,ACE2 does not convert angiotensin I to
angiotensin II, and moreoverACE inhibitors do not
block its activity
4
Monika Rella, Richard Jackson, Tony Turner
5. Amino acid sequences and ACE/ACE2 cleavage sites of various peptides
Eriksson et al. Current Biology 2002
6. PheProHisILeTyrValArgAsp
1 2 3 4 5 6 7 8
N C
ProHisILeTyrValArgAsp
1 2 3 4 5 6 7
N C
Phe
ACE2
Ang II (1-8)
Ang-(1-7)
ACE2 catalyzes the conversion of Ang II to Ang ( 1-7)
8. Native Soluble ACE2 740 aa (100-110 kDa)
Transmembrane domain
Signal peptide
Catalytic domain
Full length ACE2 805 aa (>110 kDa)
N- -C
ACE2 is a tissue enzyme widely distributed preferentially in epithelial cells .
Where is ACE2 located ?
From Davidson ,Wysocki and Batlle Hypertension 2020 , in press.
9. 9
Serfozo et al. Hypertension 2019
POP = Prolyl endopeptidase ( also known as PEP)
11. Immunofluorescence staining of ACE; green; and ACE2 (red; middle) in proximal tubules.
Minghao Ye et al. JASN 2006;17:3067-3075
In polarized epithelia like kidney , lungs and intestine ACE2 is localized in the apical site
Normallung tissue
Type IIalveolarcells
Hamming J pathol. 2004 jun; 203:631-637
12. ACE2 and ACE immunogold labeling in glomeruli.
Minghao Ye et al. JASN 2006;17:3067-3075
13. Triple immunofluorescence staining of ACE (green; A), ACE2 (red; D), and the endothelial cell
marker platelet-endothelial cell adhesion molecule (PECAM-1; blue; B and E).
Minghao Ye et al. JASN 2006;17:3067-3075
14. Fig. 1. (ACE) (green; A) and ACE2 (red; B) in a kidney arteriole from mouse kidney. Merging both images show no
colocalization of ACE and ACE2 (C). By contrast, neighboring tubules (see arrow) stain in yellow
Soler et at AJP 2008 DOI: (10.1152/ajprenal.90488.2008)
19. 19Mizuri et al. AJKD 2008
Expression of ACE and ACE2 in control individuals (left) and with diabetic kidney disease ( right)
20. ACE2 inhibitors
• MLN- 4760 ( MILLENIUM )
• DX-600
• In vivo MLN-4760 can cause worsening of kidney disease ( Ye et al. Hypertension 2012 , Soler et al. Kidney int. 2007)
22. 22Oudit et al. Diabetes 2010
Human Recombinant ACE2 Reduces the Progression of Diabetic Nephropathy (Akita mice)
23. Effect of ACE2 Fc in a Renin Transgenic Mice: a model of Ang II dependent
hypertension
23Liu et al. Kidney Int. 2008
24. ACE2 amplification using native ACE2 failed to improve early DKD caused
by STZ administration
Wysocki et al. Kidney Int. 2017
25. ACE2 activity after native ACE2 administration
Wysocki et al. Kidney int. 2017
26. Native ACE2
740 aa (100-110 kDa)
Catalytic domain
??? aa kDa
Short ACE2 Catalytic domain
Shortening of native soluble ACE2
-C
Jan Wysocki MD , PhD
27. Native Soluble ACE2
1-740 aa
1-605 aa
(~100-110 kD)
(~50 kD)1-522 aa
(~69 kD)
Recombinant ACE2 constructs
Truncations from the C-terminus
1-650 aa (~75 kD)
Full length ACE2
805 aa (>110 kD)
1-619 aa (~71 kD)
1-805 aa
- No Enzymatic Activity
28. Short ACE2 variants are filterable whereas native ACE2 is not
Mina Shirazi et al. ASN 2019
31. Highlights
Study of the ACE2 receptor for SARS-CoV1
• ACE2 as a Functional receptor for the SARS-CoV1. Wenhui Li et al, Nature, 2003.
• SARS-CoV1 binding domain with ACE2 Receptor. Fang Li et al, Science, 2005.
• SARS-CoV1 binding Affinity to ACE2 receptor. Fang Li et al, Antiviral Research , 2013.
Structure of SARS Coronavirus spike receptor-binding domain complexed with ACE2 receptor
A. ACE2 (green), RBD (cyan) and RBM (red).
B. Distribution of tyrosines (magneta) and Cysteines (yellow)
Fang Li et al, SCIENCE; Sep 2005.
32. • Receptor recognition by SARS-CoV2 to ACE2 Receptor. Fang Li et al, Journal of Virology , Jan 2020.
• SARS-CoV2 uses ACE2 receptor and TMPRSS2 for entry into target cells. Hoffmann, Biorxiv, Jan 2020.
• Cryo-EM structure of the SARS-CoV-2 spike in the prefusion conformation. Wrapp et al, Science, Mar 2020.
• Structure of the SARS-CoV-2 spike RBD bound with ACE2 receptor Lan et al, Nature, Mar 2020.
• Structural basis for the recognition of the SARS-CoV2 by ACE2 Receptor. Yan et al, Science, Mar 2020.
• Structure, Function, and Antigenicity of the SARS- CoV-2 Spike Glycoprotein . Walls et al, Cell, Apr 2020.
• SARS-CoV C-terminal domain with ACE2 receptor. Wang et al, Jama, Apr 2020.
Highlights of ACE2 as receptor for SARS-CoV2
Crystal structure of the SARS-CoV-2 bound with the ACE2
receptor
Overall structure of SARS-CoV-2 RBD bound with
ACE2.
1. ACE2 (green)
2. Receptor-binding domain (cyan)
3. Receptor-binding motif (red)
Lan et al, Nature , Mar 2020.
33. SARS-CoV2 bind to the human ACE2 Receptor and priming by TMPRSS2
Binding
1. ACE2 Receptor (Blue).
2. Spike Protein (Green).
3. TMPRSS2 (Red).
Activation
TMPRSS2*
Fusion
* TMPRSS2: Transmembrane protease , serine 2.
From Davidson ,Wysocki and Batlle Hypertension 2020 , in press.
34. (From Batlle et al. Clinical Science 2020 )
Proposed mechanism whereby soluble ACE2 attenuates viral cell entry by
competing with full length ACE2 in the plasma membrane
35. 35
Animal models of SARS-CoV-2
• Transgenic mice
• Syrian Hamsters
• Ferrets and Cats
• Nonhuman primates
42. 42
What about the use of Ang II as a vasopressor in COVID patients ?
Courtesy of Dr Matthew Sparks
The COVID-19 and ACE2 in Cardiovascular, Lung, and Kidney Working Group
43. Angiotensin II is increased in Acute Lung Injury (experimental)
43
Imai et al, Nature,2005
44. Effect of Ang II on ACE2 in a cell model
Deshotels et al Hypertension 2014
45. Ghallager et al. Am J Physiol Cell 2004
Regulation of ACE2 protein by Ang II
47. The renin-angiotensin-aldosterone system
Vaughan, DE JCI 1995
Vaughan DE Am J Cardiol 2001
Dzau et al. Am j cardiol 2001
Vaduganathan NEJM 2020
Wan et al J Virol 2020
Kuba Nat Med 2005
ACE
Angiotensinogen
Angiotensin-I
RENIN
Angiotensin-II
Angiotensin-I – 7
Angiotensin-1- 9
ACE2
Spike
protein
ACE2
fibrinolysis
Hypercoagulable
State
Acute lung injury
Inflammation
Platelet
activation
Courtesy of Dr Hau Kwaan
48. Prognosis of Acute Organ Injury
Incidence(%) 28-day mortality (%)
Overall 28-day mortality: 35.4%
↑SCr ≥100% or RRT
Gupta et al. JAMA July 2020
49. Targeting of ACE2 by SARS-CoV-2 results in angiotensin dysregulation, innate and adaptive
immune pathway activation, and hypercoagulation to result in organ injury and AKI associated
with COVID-19.
Daniel Batlle on behalf of the The COVID-19 and ACE2 in
Cardiovascular, Lung, and Kidney Working Group et al. JASN
doi:10.1681/ASN.2020040419
50. Marquez A. and Batlle D. , Kidney Int. 2019
What does ACE2 do ?
51. B.
Short ACE2 variant improves AKI in the ischemia reperfusion model
Mina Shirazi et al. ASN 2019
52. Tilman Muller and Alonso Marquez Jeannette Tang
Gvantca Gulua and Mina Shirazi
Peter Serfozo
Benedikt Marahrens
Enrique Lores
Jan Wysocki MD , PhD Minghao Ye , MD
54. RAS Inhibitors in
Hypertension and
Heart Failure:
TRUTHS AND MISTRUTHS
OF TREATMENT IN THE
COVID-19 ERA
J o r d y C o h e n , M D , M S C E
A s s i s t a n t P r o f e s s o r o f M e d i c i n e a n d E p i d e m i o l o g y
R e n a l - E l e c t r o l y t e a n d H y p e r t e n s i o n D i v i s i o n
P e r e l m a n S c h o o l o f M e d i c i n e , U n i v e r s i t y o f P e n n s y l v a n i a
@ j o r d y _ b c
55. Disclosure information
•Funding: NIH (NHLBI) K23-HL133843
•Disclosures: I have no financial relationships with commercial interests to disclose. I am co-PI and
chair of the DCC of the Randomized Elimination or Prolongation of ACE Inhibitors and ARB in
Coronavirus Disease 2019 (REPLACE COVID) trial (NCT04338009) and a contributor to
nephjc.com/news/covidace2
•Off-Label Use: My presentation includes cautionary discussion of off-label or investigational use of
ACE Inhibitors and ARBs in COVID-19
58. … a hypothesis
emerged
•“The most frequent comorbidities reported in… studies of
patients with COVID-19 are often treated with angiotensin-
converting enzyme (ACE) inhibitors”
•SARS-CoV and SARS-CoV-2 bind to their target cells through ACE2,
which is expressed by epithelial cells of the lung, intestine, kidney,
and blood vessels
•ACE2 is “upregulated” by ACEIs and ARBs
•“We suggest that patients with cardiac diseases, hypertension,
or diabetes, who are treated with ACE2-increasing drugs, are
at higher risk for severe COVID-19 infection and, therefore,
should be monitored for ACE2-modulating medications, such
as ACE inhibitors or ARBs”
Fang L et al, Lancet Resp Med 2020;8(4):E21
59. •49,556,127 US adults are taking medication
for the treatment of hypertension
•Among those, 41,329,810 (83%) are taking an
ACEI or ARB
National Health and Nutrition Examination Survey data, c/o Bress AP
The gravity of
the hypothesis
65. Hierarchy of
quality of evidence
•Case series fall somewhere
between expert opinion and
ecological studies
Meta
RCTs
Cohortstudies
Case-control studies
Cross-sectional studies
E c o l o g i c a l s t u d i e s
Case reports & case series
E x p e r t o p i n i o n & e d i t o r i a l s
Ho PM et al, Circ 2008;118(16):1675–1684
67. Hypertension
and aging
•>75% of individuals over age
75 have a diagnosis of
hypertension
Whelton PK et al. J Am Coll Cardiol 2018; 71(19)
SBP/DBP ≥130/80 mm Hg or
Antihypertensive Medication
SBP/DBP ≥140/90 mm Hg or
Antihypertensive Medication
Overall, crude 46% 32%
Men
(n=4717)
Women
(n=4906)
Men
(n=4717)
Women
(n=4906)
Overall, age-sex
adjusted
48% 43% 31% 32%
Age group, years
20–44 30% 19% 11% 10%
45–54 50% 44% 33% 27%
55–64 70% 63% 53% 52%
65–74 77% 75% 64% 63%
75+ 79% 85% 71% 78%
68. Hypertension
and aging
•>75% of individuals over age
75 have a diagnosis of
hypertension
Garg S et al, MMWR 2020 69(15);458–464
70. ACE2ACE
Mas
Renin
AT2RAT1R
Angiotensinogen
Ang IIAng I Ang-(1-7)
Vasoconstriction
Renal sodium and water reabsorption
Oxidative stress
Inflammation
Fibrosis
Impaired fibrinolysis
ACEI
ARB
Cohen JB et al, J Clin Hypertens 2020, in press
71. South AM et al, Nat Rev Nephrol 2020;16:305-307
72. South AM et al, Nat Rev Nephrol 2020;16:305-307
74. Summary of
the evidence in
March 2020
•Case series showed many patients with concomitant COVID-19
and hypertension (which could potentially be explained by age)
•In some experimental models, ACEIs and ARBs increase ACE2
expression
• This could potentially lead to increased SARS-CoV-2 virulence
• However, these findings are not consistent across studies, and have not been
corroborated in humans
•Alternatively, animal models of SARS-CoV-1 suggest that
overexpression of ACE2 protects against lung injury
• ACEIs and ARBs could improve mechanisms of host defense or
hyperinflammation
Sparks MA et al, Clin J Am Soc Nephrol 2020 7;15(5):714-716
75. •“We suggest that patients with cardiac diseases, hypertension, or diabetes,
who are treated with ACE2-increasing drugs, are at higher risk for severe
COVID-19 infection and, therefore, should be monitored for ACE2-modulating
medications, such as ACE inhibitors or ARBs”
Fang L et al, Lancet Resp Med 2020;8(4):E21
80. … and the medical societies (thankfully) reacted
Society Summary of recommendations
American Heart Association, Heart Failure Society of
America, American College of Cardiology
Continue ACEis/ARBs for all patients already prescribed them
European Society of Hypertension Continue ACEis/ARBs due to lack of evidence to support differential use in COVID-19 patients
In those with severe symptoms or sepsis, antihypertensive decisions should be made on a case-by-case
basis
Hypertension Canada Continue ACEis/ARBs due to lack of evidence that patients with hypertension or those treated with
ACEis/ARBs are at higher risk of adverse outcomes from COVID-19 infection
Canadian Cardiovascular Society Continue ACEis/ARBs and Angiotensin Receptor Neprilysin Inhibitors due to a lack of clinical evidence to
support withdrawal of these agents
The Renal Association, United Kingdom Continue ACEis/ARBs due to unconvincing evidence that these medications increase risk
International Society of Hypertension Routine use of ACEis/ARBs to treat hypertension should not be influenced by concerns about COVID-19
in the absence of compelling data
American College of Physicians Continue ACEis/ARBs because there is no evidence linking them to COVID-19 disease severity, and
discontinuation of antihypertensive therapy without medical indication could in some circumstances
result in harm
British and Irish Hypertension Society All patients taking ACEi/ARBs should continue to do so during the COVID-19 pandemic; patients could
be put at risk by stopping these medications until we have more information
Sparks MA and Hiremath S et al, nephjc.com/news/covidace2
83. Clinical trials for RAS blockade and COVID-19
Continuing or discontinuing ongoing RAS blockade
Study Identifier Target N
Country
Population Interventions Primary Outcome
NCT04329195
(ACORES-2)
554
France
Hospitalized with COVID-19 Discontinue ACEI/ARB
Comparator: Continue ACEI/ARB (open-label)
Time to 2-point improvement on WHO
scale or discharged alive up to day 28
NCT04338009
(REPLACE COVID)
152
United States
(International)
Hospitalized with COVID-19 Discontinue ACEI/ARB during hospitalization
(resumed on discharge)
Comparator: Continue ACEI/ARB throughout
hospitalization (open-label)
Composite global rank score for death,
mechanical ventilation, and multiorgan
dysfunction
NCT04351581
(RASCOVID-19)
215
Denmark
Hospitalized with COVID-19 Continue ACEI/ARB at the same dose
throughout hospitalization
Comparator: Discontinue ACEI/ARB during
admission for up to 30 days (open-label)
Days alive and out of hospital by day 14
NCT04364893
(BRACE-CORONA)
500
Brazil
Hospitalized with COVID-19 Continue ACEI/ARB for 30 days
Comparator: Stop ACEI/ARB for 30 days
(open-label)
Median days alive and out of the hospital
from enrolment to day 30
NCT04353596
(ACEI-COVID)
208
Austria and
Germany
Outpatient or hospitalized with COVID-19 Discontinue ACEI/ARB
Comparator: Continue ACEI/ARB (open-label)
SOFA score and death at 30 days
Sparks MA and Hiremath S et al, nephjc.com/news/covidace2
84. De novo RAS blockade
Study Identifier Target N
Country
Population Interventions Primary Outcome
NCT04340557 200
United States
Hospitalized with COVID-19 requiring
supplemental oxygen
Losartan 12.5 mg twice daily for up to 10
days
Comparator: No losartan (open-label)
Mechanical ventilation up to day 45
NCT04351724
(ACOVACT substudy B)
500
Austria
Outpatient or hospitalized with COVID-19 Candesartan titrated to BP <120/80 mm Hg
Comparator: Non-ACEI/ARB
antihypertensive (open-label)
Time to sustained improvement >48
hours on the WHO scaleup to day 29
NCT04311177 580
United States
Outpatient with COVID-19 Losartan 25 mg daily
Comparator: Placebo (blinded)
Hospitalization within 15 days
NCT04328012
(COVIDMED group 3)
4000
United States
Hospitalized with confirmed COVID-19 Losartan 25 mg daily for 5-14 days
Comparator: Placebo (blinded)
NIAID COVID-19 ordinal severity scale at
day 60
NCT04335786
(PRAETORIAN-COVID)
651
Netherlands
Hospitalized with confirmed COVID-19 Valsartan 160 mg twice daily up to 14 days
Comparator: Placebo (blinded)
ICU admission, mechanical ventilation or
death within 14 days
Clinical trials for RAS blockade and COVID-19
Sparks MA and Hiremath S et al, nephjc.com/news/covidace2
89. Observational
data of RAS
blockade in
COVID-19
Death
Death
? ACEI/ARB
Hospitalization for
COVID-19
No ACEi/ARB
ACEI/ARBNo ACEi/ARB
Cohen JB et al, Circ Res 2020 5;126(12):e140-e141
91. Observational
data of RAS
blockade in
COVID-19
Cohen JB et al, under review
Paper Design Question
Mehta N et al, JAMA
Cardiol doi:10.1001/
jamacardio.2020.1855
Prospective cohort
18,472 patients tested for COVID-19
2,285 (12%) on ACEI/ARB
ACEI/ARB use and risk of COVID-19 test
positivity
Mancia G et al, N Engl J
Med 2020; 382:2431-
2440
Case-control study
6,272 cases and 30,759 controls
8,071 (22%) on ACEI/ARB
ACEI/ARB use and risk of COVID-19 test
positivity and severe COVID-19
Reynolds et al, N Engl J
Med 2020; 382:2441-
2448
Retrospective cohort
12,594 patients tested for COVID-19
4,564 (36%) on ACEI/ARB
ACEI/ARB use and risk of COVID-19 test
positivity and severe COVID-19
de Abajo PFJ et al,
Lancet 2020; 395:1705-
1714
Case-control study
1,139 cases and 11,390 controls
2,432 (19%) on ACEI/ARB
ACEI/ARB use and risk of COVID-19
hospitalization
92. Observational
data of RAS
blockade in
COVID-19
Cohen JB et al, under review
Paper Findings
Approach to
confounding
Selection/
Collider Bias
Mehta N et al, JAMA
Cardiol doi:10.1001/
jamacardio.2020.1855
OR 0.97; 95% CI 0.81, 1.15 for test
positivity
P-score weighting Conditioned on
being tested
Mancia G et al, N Engl J
Med 2020; 382:2431-
2440
ACEI: OR 0.96; 95% CI 0.87, 1.07
ARB: OR 0.95, 95% CI 0.86, 1.05 for
test positivity
Matching
Adjustment
Conditioned cases
on a positive test
Reynolds et al, N Engl J
Med 2020; 382:2441-
2448
Median % difference likelihood
ACEI: 0.1, 95% CI -4.3, 4.5
ARB: 1.6, 95% CI 2.6, 5.8 for test
positivity
P-score matching Conditioned on
being tested and on
having a positive
test
de Abajo PFJ et al,
Lancet 2020;
395:1705-1714
OR 0.94; 95% CI 0.77, 1.15 for COVID-
19 hospitalization
Matching
Adjustment
Conditioned cases
on hospitalization
for COVID-19
93. Observational
data of RAS
blockade in
COVID-19
Flacco ME et al, Heart 2020 0:1–6. doi:10.1136/heartjnl-2020-317336
Mackey K et al, Ann Intern Med 2020;173:195-203. doi:10.7326/M20-1515
94. Early RAS
blockade RCT
data
Duarte M, et al. medRxiv 2020.08.04.20167205; doi: 10.1101/2020.08.04.20167205
Telmisartan for treatment of Covid-
19 patients: an open randomized
clinical trial. Preliminary report.
•Telmisartan 80 mg bid during
14 days plus standard care vs.
standard care alone for 14
days
•78 patients were included in
the interim analysis
•Telmisartan treated patients
had lower time to discharge
(median time to discharge
control group=15 days;
telmisartan group=9 days)
Interpret with caution
95. Lung and kidney
ACE2
expression with
ACEI/ARB
therapy
Wysocki J et al, JASN 2020; 31, DOI: 10.1681/ASN.2020050667
Kidney
Lung
96. Summary
•Pandemics bring out some of the best the best and worst in medical publications and journalism
•Early case series pointed towards a high prevalence of hypertension, diabetes, and CVD in patients hospitalized with
COVID-19, which led to speculation about RAS blockade as a potential culprit
• None of these studies were adjusted for age
•We’ve learned new information about hypertension, RAS blockade, and COVID-19
• Observational evidence suggests no association of ACEI/ARB use and risk and severity of COVID-19, but these studies have
limitations
• RCTs are ongoing; not all RCTs are created equally. Consider the design and reporting when interpreting results
• ACEI/ARBs do not seem to increase ACE2 expression in the kidneys and lungs in mice
•Premature or unnecessary discontinuation of ACEIs/ARBs could elevate BP and cause decompensation of chronic
health conditions. De novo initiation of ACEIs/ARBs for use in treating COVID-19 is not recommended at this time.