New research from the University of Alabama, Birmingham (UAB), suggests that estrogen may save lives on the battlefield and in cases of trauma. Between 2001 and 2011, more than 80 percent of potentially preventable U.S. military deaths were caused by blood loss and septicemia (blood poisoning). Although their injuries were potentially survivable, these soldiers bled to death before they could be transferred to the medical facilities that might save them. Studies show that estrogen (aka the female sex hormone) may be the key that allows those wounded in combat to survive long enough to make it to field hospitals. The results so far are promising enough that researchers at UAB have recently received a $10 million contract from the U.S. Department of Defense to begin human trials to see if synthetic estrogen really can help soldiers survive severe blood loss.

Lead researcher Irshad Chaudry, PhD, also the director of the Center for Surgical Research at UAB, has been studying the life-saving potential of estrogen for 19 years. Strangely enough, he and fellow researcher Rene Zellweger began the work due to a random mix up at the lab. They were studying bacterial blood infections in trauma-hemorrhaged patients using mice. Their vendor mistakenly sent them female mice, rather than the usual male. They assumed that the female mice wouldn’t work well as subjects because of their fluctuating hormonal levels; however, they continued with the study anyway and were surprised to discover that the female mice resisted infection better than the male mice. When they tried to repeat the experiment with another batch of female mice, the new mice were no more resistant to infection than the male mice. So what had made those first mice so resilient? Chaudry and Zellweger realized that this discrepancy was caused by the mice being in different stages of their menstrual cycles; the first, and more infection-resistant, set of mice were in a menstrual phase characterized by very high levels of estrogen.

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So what does estrogen actually do in cases of trauma? Chaudry has found that synthetic estrogen (called “E2”) aids cardiovascular and liver function in subjects suffering from severe blood loss. According to an article by Jeff Hansen for UAB, estrogen “dilate[s] blood vessels and speed[s] the movement of fluid from the tissue compartment into the blood compartment,” improving blood flow to vital organs. Hansen describes what estrogen does by paraphrasing English trauma researcher Harry Berrington “Berry” Stoner, M.D.: “The body’s blood system is like a swamp after trauma, and anything that turns the swamp into a running brook is the answer for treating shock.”

In 2005, Chaudry and his colleagues entered a competition from the U.S. Defense Advanced Research Projects Agency (DARPA) that challenged researchers to find a way to keep someone alive for three hours after major blood loss. Chaudry was able to demonstrate that E2 could do so. In the next phase, Chaudry, his researchers, and DARPA teamed up to create another variant of synthetic estrogen, EE-3-SO4, which was shown to be effective at prolonging life up to six hours after a major trauma.

Chaudry and his researchers are preparing to begin the first human trials on EE-3-SO4. In a paper last June, Chaudry explained, “If these study findings translate to the battlefield, additional time will be available for transport of the wounded to safer locations where standard resuscitation measures can be accomplished.”

If the human trials are successful, it isn’t only wounded soldiers who will benefit. The drug could help trauma patients outside of combat situations to survive until they can receive medical care, and it could be particularly effective as a treatment for traumatic brain injuries. According to Hansen, experiments have shown that “the estrogen is able to reduce cerebral edema, increase brain blood flow, increase cognitive function and memory, and lessen brain cell death.”

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