Diseases like heart disease and cancer have been known to affect men and women differently. But could a disease as common as the flu have that much of a difference between genders?
According to a new study, yes. The study, published in the American Journal of Physiology – Lung Cellular and Molecular Physiology, has found that women are more protected against the flu through the female sex hormone estrogen, than men are.
How does the influenza virus work in our bodies, exactly?
When a virus enters the body through a cell and replicates itself inside that cell is when the virus begins infecting the body. The virus begins to spread when those replications spread to other cells and that can in turn, increase the severity of the disease as well as the likelihood of the virus spreading to other people.
If the replication process is weak, meaning there are less copies of the virus, the disease is likely to be less severe. This also decreases the chances of it spreading, according to Sabra Klein, the associate professor at Johns Hopkins who led this research.
To investigate how the flu virus might affect men and women differently, Klein and her team of researchers gathered nasal cells from both men and women. These are the cells most likely to be infected by the flu virus. The team then cultured and exposed the cells to both the flu virus and different forms of estrogen.
They found that when the cells were exposed to both the flu virus and estrogen, the virus’ replication process was reduced in only female cultured nasal cells. The team also found estrogen boosted antiviral properties in the presence of this virus through the estrogen receptor beta – proteins that act as “gatekeepers,” only allowing allow entry to cell-stimulating molecules that can bind to them.
This new study breaks new ground as the cells used were directly isolated from patients, allowing the researchers to identify the sex-specific effect of estrogen. It was also the first study to identify the receptor that allows estrogen to be as antiviral as it is – helping us understand further the mechanisms behind their effects.
So how does this relate to the real world?
Women who are premenopausal may not see the antiviral effect of estrogen as their levels go up and down in the menstrual cycle. But women on certain kinds of birth control or women undergoing hormone replacement for menopause may be more protected from the flu, given they get a more constant supply of estrogen.
These findings highlight the need to continue to conduct thorough research on how diseases affect the sexes differently to provide new, more effective ways to treat patients in the real world for all kinds of diseases.