Circulating angiotensin converting enzyme 2 and COVID-19

Figure 1 Mechanism of action of angiotensin converting enzyme 2. The angiotensin converting enzyme (ACE) metabolizes angiotensin (Ang) I to Ang II, which activates Ang II type 1 receptors (AT1R) and Ang II type 2 receptors (AT2R), leading to increased vasoconstriction, inflammation, fibrosis, lung damage, and edema. Conversely, angiotensin converting enzyme 2 (ACE 2) counteracts Ang I by generating angiotensin 1-7 [Ang-(1-7)], which then interacts with the G-protein-coupled receptor Mas to exert vasoprotective actions. Circulating ACE2 (cACE2) inhibits S-mediate infection and reduces viral diffusion to different organs.