Now, researchers from the University of Buffalo believe they have discovered one way that estrogen protects women from cardiovascular disease -- it acts as an anti-inflammatory.
"Atherosclerosis (hardening of the arteries) is thought to be a chronic inflammatory disease," says study author Dr. Paresh Dandona, a professor of medicine at the University of Buffalo School of Medicine and Biomedical Sciences. "What is exciting is that we have published the first data in humans that estrogen does have anti-inflammatory properties that may account for the protective effect seen in women during the pre-menopausal years."Cardiovascular disease is responsible for almost 1 million deaths every year. An estimated 20 percent of all Americans have some form of cardiovascular disease, which includes high blood pressure, heart disease and stroke.
Studies on estrogen to prevent heart disease in post-menopausal women have been conflicting, with some showing an effect while others show none. To eliminate some of the variables, Dandona and his colleagues recruited nine men for their study. Dandona says because men don't have a menstrual cycle, they don't have a fluctuating level of estrogen that could affect the study's results.
The average age of the men was 32, and none were overweight.
The volunteers were given a shot of 5 milligrams of the hormone replacement therapy, Premarin. That dose is about four times what most women take, according to Dandona. The researchers collected blood samples before the injection and at two, four and six hours after the injection.
They found estrogen acted as an anti-inflammatory and reduced the amount of free radicals circulating in the blood. Estrogen also lowered levels of C-reactive protein, a substance that measures the amount of inflammation in the blood vessels. Estrogen appeared to be most effective four hours after the injection.
Results of the study were presented today at the annual meeting of the Endocrine Society in San Francisco.
Besides cardiovascular disease, Dandona points out that if estrogen is acting as an anti-inflammatory, it could prove useful in treating other diseases caused by inflammation, such as Alzheimer's disease.
Dr. Steven Almany, medical director of cardiology at William Beaumont Hospital in Royal Oak, Mich., says this study is most interesting because it suggests that estrogen might be useful in treating acute coronary symptoms.
"In the short-term, they did have some effect on some of the things that cause damage, like free radicals," Almany says.
However, he points out this is a very small study, using a very large dose of estrogen on young men who usually don't get cardiac disease. "It's not real world," he adds.
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