Angiotensin-converting enzyme 2 (ACE2) and COVID-19
COVID-19 is more severe in older adults and/or patients with comorbidities, such as diabetes, obesity, kidney disease or hypertension, suggesting a role for insulin resistance.15 Although differences exist between countries, the same risk factors for severity were found globally16-20, suggesting common mechanisms. Moreover, the severe outcomes of COVID-19 - including lung damage, cytokine storm or endothelial damage - appear to exist globally, again suggesting common mechanisms.
The angiotensin-converting enzyme 2 (ACE-2) is part of the dual system, the renin-angiotensin-system (RAS), including the ACE-Angiotensin-II-AT1R axis. AT1R is involved in most Angiotensin II effects, including oxidative stress generation, pro-inflammatory, pro-fibrotic effects in the respiratory system, endothelial damage and insulin resistance.21,22 SARS-CoV-2 binds to and downregulates ACE-2, enhancing the AT1R axis 23, likely to be associated with insulin resistance 24,25 but also to severe outcomes of COVID-19.