Gender-related differences in the development of atherosclerosis: studies at the cellular level.

1. Calcified arteriosclerotic lesions have been recognized early in life as abnormalities in coronary arteries. 2. We examined coronary arterial plaques as an undecalcified tissue and revealed widespread mineralization within the plaque. Non-collagenous proteins that regulate calcification, such as osteopontin, have been identified within the atherosclerotic plaque. In vitro, smooth muscle cells derived from porcine coronary arteries express non-collagenous proteins and type I collagen. 3. We have demonstrated that oestrogen regulates the proliferation of smooth muscle cells obtained from the coronary arteries of sexually mature pigs. The inhibition of proliferation by beta-estradiol occurred in coronary smooth muscle cells (VSMC) obtained from female animals and no proliferation was noted in VSMC isolated from intact male animals after exposure to beta-estradiol. 4. The dynamic changes in matrix composition and cellular proliferation in atherosclerotic vessels may be responsible for the calcification associated with the atherosclerotic plaque.