Serum ACE activity and plasma ACE concentration in patients with SARS-CoV-2 infection

Significant controversy has arisen over the role of the renin-angiotensin-aldosterone system (RAAS) in COVID-19 pathophysiology. In this prospective, observational study, we evaluated plasma angiotensin converting enzyme (ACE) concentration and serum ACE activity in 52 adults with laboratory-confirmed SARS-CoV-2 infection and 27 non-COVID-19 sick controls. No significant differences were observed in ACE activity in COVID-19 patients versus non-COVID-19 sick controls (41.1 [interquartile range (IQR): 23.0-55.2] vs. 42.9 [IQR 13.6-74.2] U/L, p = .649, respectively). Similarly, no differences were observed in ACE concentration in COVID-19 patients versus non-COVID-19 sick controls (108.4 [IQR: 95.8-142.2] vs. 133.8 [IQR: 100.2-173.7] μg/L, p = .059, respectively). Neither ACE activity (p = .751), nor ACE concentration (p = .283) was associated with COVID-19 severity. Moreover, neither ACE activity, nor ACE concentration was correlated with any inflammatory biomarkers.