The female gender is definitely not the weaker sex. A new study found that the main female sex hormone estrogen helps women fight flu virus.
Specifically, researchers from the Johns Hopkins Bloomberg School of Public Health discovered that it does not matter what form of estrogen is present. Both the naturally occurring and artificial forms or those used in hormone replacement pills can halt the replication of influenza A virus.
Estrogen has been found to weaken viruses that cause Ebola, HIV and hepatitis. The effect of the hormone on flu viruses, however, has not yet been investigated, says lead author Dr. Sabra Klein.
To identify the role of the hormone in the common flu, the scientists obtained samples of nasal passage cells from both female and male subjects. They then exposed the cells to varied types of synthetic estrogen-like substances found in hormone replacement medicines. Aside from that, they also subjected the samples to another estrogen-like chemical called bisphenol A, which is used for hormone therapy.
After estrogen contact, the researchers exposed the samples to influenza A virus cells, which are commonly prevalent during the yearly flu season between December and February.
The results of the study showed that female cells that received estrogen derivatives had almost 1,000 times lesser viral replications than those that were not exposed.
The researchers delved deeper into the reason behind the mechanism. They found that binding to estrogen receptors can reduce the activity of over 30 genes involved in cell metabolism, thus slowing their metabolic activity and halting them from creating viral particles.
Men also produce estrogen, but their cells have significantly lesser receptors for the hormone. This maybe the reason why the male cells did not exhibit the same promising viral replication results.
While the study looks beneficial for women, Klein says it may not produce highly positive effects for all.
"Because estrogen levels cycle in premenopausal women, it may be difficult to see this protective effect in the general population," she says.
Despite the little setback, Klein says the study suggests that women who are presently undergoing hormone replacement therapy may get an added benefit of decreasing their susceptibility to infection.
Most importantly, Klein does not recommend starting on hormone therapy now just for flu-preventive purposes. Estrogen's effects are highly varied; one may be as good as strengthening bones while another as bad as increasing cancer risks.
The study was published online ahead of print in the American Journal of Physiology - Lung Cellular and Molecular Physiology.
Photo : David Goehring | Flickr
