Angiotensin-converting enzyme 2 (ACE2) facilitates the cellular entry of the severe acute respiratory syndrome-associated coronavirus 2 (SARS-CoV-2), which causes the coronavirus-2019 (COVID-19) disease. Recent reports have shown worse outcomes in men with COVID-19 infection compared to women. We review the hypothesis that sex-related differences in outcomes in COVID-19 are due to different activity of ACE2 between men and women. We also show that studies in humans have demonstrated no significant difference in serum ACE2 levels between healthy men and women. However, men with hypertension and heart failure typically have higher level of serum ACE2 activity compared to women. We hypothesize that the worse outcomes in men with COVID-19 compared to women is likely due to higher prevalence of hypertension and heart failure among men compared to women. To test this hypothesis, studies to compare the outcomes of COVID-19 infection between men and women with no preexisting heart diseases are needed.

血管紧张素转换酶2（ACE2）促进严重急性呼吸系统综合症相关冠状病毒2（SARS-CoV-2）的细胞进入，这会导致冠状病毒2019（COVID-19）疾病。最近的报告显示，与女性相比，患有COVID-19感染的男性的预后较差。我们审查了这一假设，即在COVID-19中与性别相关的结局差异是由于男女之间ACE2的活性不同所致。我们还显示，人体研究表明，健康男性和女性之间血清ACE2水平无显着差异。但是，患有高血压和心力衰竭的男性通常比女性具有更高水平的血清ACE2活性。我们假设与女性相比，COVID-19男性患者的预后较差，可能是由于男性与女性相比高血压和心力衰竭的患病率更高。