title: Detection of soluble angiotensin-converting enzyme 2 in heart failure: insights into the endogenous counter-regulatory pathway of the renin-angiotensin-aldosterone system.
abstract: OBJECTIVE
  We sought to determine whether circulating soluble angiotensin-converting enzyme 2 (sACE2) is increased in the plasma of patients with heart failure (HF).
  
  
  BACKGROUND
  Angiotensin-converting enzyme 2 (ACE2) is an integral membrane protein that antagonizes the actions of angiotensin II and prevents the development of HF in animal models. However, because of the need for invasive cardiac tissue sampling, little is known about whether ACE2 is involved in the pathophysiology of HF in humans.
  
  
  METHODS
  We developed a sensitive and specific assay to measure sACE2 activity in human plasma and screened a heterogeneous group of patients suspected of having clinical HF.
  
  
  RESULTS
  Increasing sACE2 plasma activity strongly correlated with a clinical diagnosis of HF (p = 0.0002), worsening left ventricular ejection fraction (p < 0.0001), and increasing B-type natriuretic peptide levels (p < 0.0001). Similar to B-type natriuretic peptide, sACE2 activity reflected the severity of HF, with increasing levels associated with worsening New York Heart Association functional class (p < 0.0001). These associations were independent of other disease states and medication use. We found that sACE2 activity was increased in patients with both ischemic and nonischemic cardiomyopathies and also in patients with clinical HF but a preserved left ventricular ejection fraction.
  
  
  CONCLUSIONS
  Soluble ACE2 activity is increased in patients with HF and correlates with disease severity, suggesting that a cardioprotective arm of the renin-angiotensin-aldosterone system is active in HF.
authors: Department of Internal Medicine, Heart and Vascular Institute, Cleveland, Ohio 44195, USA.
authors: Slava
authors: S
authors: Epelman
authors: W H Wilson
authors: WH
authors: Tang
authors: Stephen Y
authors: SY
authors: Chen
authors: Frederick
authors: F
authors: Van Lente
authors: Gary S
authors: GS
authors: Francis
authors: Subha
authors: S
authors: Sen
mesh_terms: D000368:Aged; D000085962:Angiotensin-Converting Enzyme 2; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000201:enzymology* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D020097:Natriuretic Peptide, Brain / Q000097:blood; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D012084:Renin-Angiotensin System / Q000502:physiology*; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013318:Stroke Volume / Q000502:physiology
chemical_list: D020097:Natriuretic Peptide, Brain; D007703:Peptidyl-Dipeptidase A; C000705307:ACE2 protein, human; D000085962:Angiotensin-Converting Enzyme 2