Men's Blood Contains Greater Concentrations of Enzyme That Helps COVID-19 Infect Cells

A study in the European Heart Journal found that men have higher levels of angiotensin-converting enzyme 2 (ACE2) in their blood than women, which may help explain why men are more susceptible to COVID-19, reports EurekAlert . "ACE2 is a receptor on the surface of cells," said University Medical Center Groningen Professor Adriaan Voors. "It binds to the coronavirus and allows it to enter and infect healthy cells after it is has been modified by another protein on the surface of the cell, called TMPRSS2. High levels of ACE2 are present in the lungs and, therefore, it is thought to play a crucial role in the progression of lung disorders related to COVID-19." People with cardiovascular conditions who take drugs targeting the renin-angiotensin-aldosterone system (RAAS) — such as angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ARBs) — did not exhibit higher ACE2 concentrations. The study disputes earlier research suggesting that RAAS inhibitors might elevate concentrations of ACE2 in plasma and boost risk of COVID-19 for persons taking these medications. "We found no evidence that ACE inhibitors and ARBs were linked to increased ACE2 concentrations in plasma," Voors said. "In fact, they predicted lower concentrations of ACE2 in the validation cohort, although we did not see this in the index cohort."