DALLAS, Texas, Aug. 7, 1998 -- For the first time researchers have shown that estrogen -- a hormone that may protect women from heart disease -- also may be a weapon for both men and women against stroke.
The study, which appears in Stroke: Journal of the American Heart Association, was conducted in rats. Researchers say the results support the possibility that estrogen given shortly after a stroke may help reduce brain damage in both men and women.
"Our findings clearly demonstrate that the benefit of estrogen can be extended to the male brain, reducing tissue injury (from stroke)," says the study's lead author, Patricia Hurn, Ph.D., associate professor of anesthesiology and critical care medicine, Johns Hopkins University School of Medicine, Baltimore.
A stroke, which occurs when blood flow to the brain is cut off, can result in brain damage or death. Stroke strikes women more often than men; however, women are more likely to recover from a stroke than men. About 4 million stroke survivors are alive today -- 1.9 million men and 2.1 million women. Hurn says that she and her colleagues' studies in animals also have found a gender difference in the amount of brain damage from stroke. Following a stroke, the female rat typically has about one-third less brain damage than the male.
To find out if this protection is from estrogen, researchers treated 36 rats with estrogen and another group of 21 "control" rats with saline (salt water). Stroke was induced by cutting off blood flow to the brain for two hours. Samples of tissues were examined to determine the amount of damaged tissue. Rats that received estrogen had about half the amount of brain damage as those treated with saline.
Thomas Toung, M.D., associate professor in anesthesiology, who co-authored the report, says, "Estrogen treatment provides striking reduction of tissue injury after stroke and may bring new treatment insights and strategies for both sexes."
Before taking the next step for human study, the researchers say they will conduct further investigations to determine how the hormone works. "Some research has suggested that it may improve blood flow to the brain during stroke or prevent some of the chemical reactions that occur during stroke that cause cell damage. But that needs to be tested," says Toung.
Richard Traystman, Ph.D., is a co-author.