Effects of Estrogen on the Expression of Noncollagenous Proteins in Coronary Arteries of Postmenopausal Women
Farout, Megan E.
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Depletion of estrogen is a key factor in the development of cardiovascular disease in postmenopausal women. The production of noncollagenous proteins (NCPs) in vascular tissue particularly, osteopontin (OP), bone sialoprotein (BSP), osteocalcin (OC), and osteonectin (ON), are associated with atherosclerosis, a disease in which the intimal layer of the arterial wall becomes thickened. Interestingly, these NCPs are involved in the calcification of atherosclerotic arteries and bone. Previous studies suggest that estrogen may inhibit the expression of NCPs within coronary arteries. In this investigation the lateral anterior descending (LAD) coronary artery of sixteen postmenopausal women were obtained at autopsy. Fifty percent of the women were on estrogen replacement therapy (ERT) and fifty percent were not on ERT. The amount of calcification detected in the LAD arteries of women on ERT was significantly less than women not on ERT. Sections of the LAD arteries were subjected to immunocytochemistry to detect OP, BSP, OC, and ON using polyclonal antibodies. Immunocytochemistry did not reveal statistically significant differences of NCPs present in the LAD arteries between the women on ERT and the women not on ERT, but this may be due to limitations in the interpretation of the data collected. Possible trends observed in selected LAD arteries from the two groups of women suggest that ERT may slow the progression and development of atherosclerosis in postmenopausal women by inhibiting the expression OP, BSP, OC and increasing the expression of ON.