A new study in the American Journal of Physiology Lung Cellular and Molecular Physiology reports, that the female sex hormone, estrogen protects women from flu. It basically has anti-viral effects against the influenza A virus.
When a team from Johns Hopkins University exposed male and female nasal cells, which are most severely affected by influenza A, to estrogen compounds and the flu, they found that the estrogen actively slowed down replication of the virus in cells from women but not men.
To examine how estrogen affects the flu virus’s ability to replicate, the research team gathered nasal cells — the cell type that the flu virus primarily infects – from male and female donors. The researchers exposed the cell cultures to the virus, estrogen, the environmental estrogen bisphenol A and selective estrogen receptor modulators (SERM), which are compounds that act like estrogen that are used for hormone therapy.
The researchers found that estrogen, SERM compound raloxifene and bisphenol A reduced flu virus replication in nasal cells from women but not men. They also observed that the estrogens initiated their antiviral effects through estrogen receptor beta. Receptors are protein structures that molecules bind with to induce cells to respond.
Other studies have shown that estrogens have antiviral properties against HIV, Ebola and hepatitis viruses. What makes our study unique is two-fold. First, we conducted our study using primary cells directly isolated from patients, allowing us to directly identify the sex-specific effect of estrogens. Second, this is the first study to identify the estrogen receptor responsible for the antiviral effects of estrogens, bringing us closer to understanding the mechanisms mediating this conserved antiviral effect of estrogens,” according to Klein.
The findings in this new study support earlier evidence from studies in animals that showed protective effects of estrogen against the flu. Klein noted that because estrogen levels cycle in premenopausal women, it may be difficult to see this protective effect in the general population. But, premenopausal women on certain kinds of birth control or post-menopausal women on hormone replacement may be better protected during seasonal influenza epidemics.
We see clinical potential in the finding that therapeutic estrogens that are used for treating infertility and menopause may also protect against the flu,” she says.
The article “Estrogenic compounds reduce influenza A virus replication in primary human nasal epithelial cells derived from female, but not male, donors” is published ahead-of-print in the American Journal of Physiology — Lung Cellular and Molecular Physiology.
So folks, that’s how estrogen protects women from flu virus, and not with men.