Given the RAAS importance to cardiovascular and kidney physiology, and the association between chronic diseases and COVID-19, could shed light on potential relationships between ACE inhibitor and ARB use and COVID-19 [9], this study aimed to clarify the effect of RAAS blockers on ACE2 and to assess the association between the chronic use of either ACEIs or ARBs on ACE2 level in clinical samples from patients with chronic cardiovascular diseases compared to healthy individuals. The gene discussed is ACE2; the disease is COVID-19.