The renin-angiotensin system - a therapeutic target in COVID-19?

COVID-19, caused by infection with SARS-CoV-2, is a disease characterised by cough, fever and fatigue, which progresses to life-threatening lung injury in approximately 5% of patients. The SARS-CoV-2 virus enters the cell via ACE2. ACE2 is a component of the renin-angiotensin system (RAS) which has an important counterregulatory effect on the classical ACE-dependent pathway. Several antihypertensives increase ACE2 expression or activity, leading to concern that this may facilitate SARS-CoV-2 entry and worsen COVID-19 disease. However, ACE2 is protective against lung injury while ANG II (which is catabolised by ACE2) is associated with lung injury both in mice and humans. We propose that medications which inhibit the RAS ACE-dependent pathway may be beneficial in treating COVID-19 and should be explored in animal models and clinical trials. Here we give an overview of the RAS pathway with respect to COVID-19 and argue that strategies which manipulate this pathway might reduce the destructive lung manifestations of COVID-19 and improve patient outcomes.