The Effect of Estrogen and Testosterone on Cholesterol Crystallization

Abstract

Lead Author's Financial Disclosures Nothing to disclose. Study Funding None. Background/Synopsis Cholesterol crystallization has been implicated in the destabilization of atherosclerotic plaque leading to rupture and cardiovascular events. This is based on volume expansion of the plaque's lipid rich necrotic core by sharp tipped cholesterol crystals. Estrogens have been recognized to provide protection form cardiovascular events in pre-menopausal women compared to their male counterparts. Objective/Purpose In this study we evaluated the role of estrogen and testosterone on cholesterol crystallization and volume expansion as a risk for plaque destabilization. Methods Graded concentrations of estradiol or testosterone (13 micrograms, 130 micrograms, and 1.3 milligrams) were mixed with cholesterol powder (3 g + 1 ml H2O) and melted in graduated cylinders and allowed to crystallize at room temperature (22 Celsius). Differences in volume expansion (delta VE) between liquid and crystalline phases were measured and compared to control tubes with H2O alone. Results Increasing concentration of estrogen was associated with a statistically significant reduction in cholesterol expansion with crystallization (p<0.01) while increasing concentration of testosterone was not associated with reduction in cholesterol expansion (p=0.52) (Figure). Conclusions Estrogen demonstrated a decreased cholesterol volume expansion with crystallization while testosterone did not. These findings are consistent with clinical observations that support the protective effects of estrogen with regards to acute cardiovascular events and an increased risk associated with testosterone. Nothing to disclose.