Telmisartan reduces systemic inflammation and alters the renin-angiotensin system in mild COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19, a respiratory viral infection that disrupts renin angiotensin system (RAS) peptide metabolism by downregulating angiotensin converting enzyme-II (ACE2), leading to accumulation of pro-inflammatory angiotensin II (AngII). We posit that angiotensin receptor blockers (ARBs) like telmisartan (TEM) can activate the pro-resolving arm of RAS (MasR/ACE2/Ang1-7), reducing lung inflammation in COVID-19 patients. In this randomized, double-blinded, placebo-controlled pilot clinical trial, outpatient SARS-CoV-2-infected study participants received either 40 mg TEM or placebo once daily. Plasma inflammatory biomarker levels revealed a reduction in global systemic inflammation with TEM treatment, corresponding with an increase in MasR. We corroborated these clinical findings with in vitro analysis. A549-ACE2 lung epithelial cells treated with TEM showed increased ACE2 and MasR, as well as decreased angiotensin II receptor type I (AT1R) and angiotensin II receptor type II (AT2R) expression levels. Additionally, AngII peptide levels decreased, while Ang(1-9) and Ang(1-7) increased. TEM treatment at physiologically achievable concentration reduced SARS-CoV-2 viral load. Taken collectively, these results show TEM mediated activation of the Ang(1-7)/MasR/ACE2 pro-resolving arm of RAS, which activates anti-inflammatory events that reduce global inflammation. These findings support the use of ARBs like TEM in mitigating COVID-19 driven alterations in RAS.