Does "good" cholesterol lower the risk of heart disease? Does estrogen play a role in lowering the risk of heart attacks? Should postmenopausal women go on hormone replacement therapy (HRT) to prevent heart disease?
Tom Dolan, UK Medical Illustrator
A UK study sheds light on these questions by presenting a new picture of the roles of estrogen, estradiol (a form of estrogen used in HRT) and good cholesterol (high-density lipoproteins, or HDL) in heart disease.
Previous studies by other scientists showed that HDL and estrogen stimulate the production of nitric oxide. A UK team, led by Eric Smart, associate professor in the Department of Pediatrics and Barnstable-Brown Chair in Diabetes Research, found that estrogen, as well as estradiol, and HDL act together to protect the heart by stimulating production of nitric oxide, which lowers blood pressure and acts as an anti-inflammatory agent.
In cell culture and animal studies, the researchers found male HDL and female HDL are different. In human studies, HDL from premenopausal women or postmenopausal women receiving estradiol stimulated the production of nitric oxide, whereas HDL from postmenopausal women did not.
The study, published last year in the Journal of Clinical Investigation, gives a new model for examining the cardiovascular effects of HDL and estrogen, and may have future implications in women's health, particularly the use of HRT for cardio-protection. This project is part of the $8.3 million National Institutes of Health Center for Biomedical Research Excellence grant, the largest single grant ever awarded in the area of women's health at UK.
UK Public Relations