ACE2 and COVID-19
The angiotensin-converting enzyme 2 (ACE2) receptor is part of the dual system - renin-angiotensin-system (RAS) - consisting of an ACE-Angiotensin-II-AT1R axis and an ACE-2-Angiotensin-(1-7)-Mas axis. AT1R is involved in most of the effects of Ang II, including oxidative stress generation,22 which in turn upregulates AT1R 23. In metabolic disorders and with older age, there is an upregulation of the AT1R axis leading to pro-inflammatory, pro-fibrotic effects in the respiratory system, and to insulin resistance.24SARS-CoV-2 binds to its receptor ACE2 and exploits it for entry into the cell. The ACE2 downregulation, as a result of SARS-Cov-2 binding, enhances the AT1R axis. 25