Gender as a regulator of atherosclerosis in murine models.

The risk of development and progression of atherosclerosis is different between males and females. Premenopausal women have a lower risk of developing atherosclerosis and cardiovascular disease than men. However, after the onset of menopause the protection associated with gender is lost and the risk of women developing atherosclerosis gradually approaches that of men. In an effort to treat the elevated risk of cardiovascular disease in postmenopausal women, hormone replacement therapy has been used. However, the results of the randomized trials of the Women's Health Initiative indicated that hormone replacement therapy may not be cardioprotective. The use of mouse models have aided in the understanding of atherosclerosis for many years. These models along with the gender effects attributed to sex hormones are being used to generate a more complete understanding of the development of atherosclerosis. Mice lacking one or both of the genes for estrogen receptors have highlighted the role of estrogen in atherosclerosis. In addition to estrogen, the effects of testosterone have been researched in many animal models and several mechanisms incorporating its role in cholesterol homeostasis have emerged. Our understanding of the pathways involved in gender effects on cardiovascular disease is incomplete, however, a plethora of animal models offer the opportunity to dissect the molecular mechanisms involved.