Immunoreactivity of the SARS-CoV-2 Entry Proteins ACE-2 and TMPRSS-2 in Murine Models of Hormonal Manipulation, Aging, and Cardiac Injury

The study investigated the impact of sex hormones, age, and cardiovascular disease on the expression of ACE-2 and TMPRSS-2 proteins, which are key for SARS-CoV-2 entry into cells, using murine models. It found that sex and gonadal hormones did not significantly affect the expression of these proteins in lung tissue, even after myocardial injury. Age, however, did impact expression, with younger mice showing higher ACE-2 expression after myocardial injury and lower TMPRSS-2 expression under both baseline and post-injury conditions. In kidney and liver tissues, female sex was associated with lower levels of ACE-2 and TMPRSS-2 expression after myocardial injury. The study also found that female reproductive history did not impact the pulmonary expression levels of these proteins. The study suggests that the higher COVID-19 mortality in males may be due to differences in immune status associated with cardiovascular comorbidities, rather than differences in ACE-2 expression.