A study published in the journal Current Hypertension Reports has found that the severity of symptoms of COVID-19 in women may reduce due to estrogen. According to researchers, this could be the underlying factor behind the risk of men have more severe outcomes from the novel coronavirus infection than women.
Leanne Groban, lead author of the study, said in a statement: "We know that coronavirus affects the heart and we know that estrogen is protective against cardiovascular disease in women, so the most likely explanation seemed to be hormonal differences between the sexes."
ACE2 and COVID-19
Estrogens are hormones that are important for sexual and reproductive development, mainly in women. They are also referred to as female sex hormones. For the study, the research team conducted a review of published preclinical data on sex-specific hormone activity, especially estrogen.
The researchers said the published literature indicated that the angiotensin-converting enzyme2 (ACE2), which is attached to cell membranes in the heart, arteries, kidneys and intestines, is the cellular receptor of the coronavirus responsible for COVID-19 infections. It helps bring the virus into the cells of those organ systems.
According to the research team, the review also pointed to estrogen's lowering the level of ACE2 in the heart, which may modulate the severity of COVID-19 in women. Conversely, higher levels of ACE2 in tissues could account for why the symptoms are worse in men than women, the study said.
Role of Estrogen
The reasons for the higher male sex-specific COVID-19-related mortality are likely to be multi-fold, including differences in lifestyle (e.g., higher rates of tobacco smoking and alcohol consumption) and innate immunity.
"We hope that our review regarding the role of estrogenic hormones in ACE2 expression and regulation may explain the gender differences in COVID-19 infection and outcomes, and serve as a guide for current treatment and the development of new therapies," Groban said. "In summary, the accumulating evidence of a somewhat lower rate of COVID-19 disease severity in women needs to be further investigated," the study authors noted.
Earlier, several studies revealed that men are more vulnerable to COVID-19 infection. Recently, a study, published in the European Heart Journal, found that men have higher concentrations of ACE2 in their blood than women, a molecule that enables the novel coronavirus to infect healthy cells in men.
(With inputs from agencies)