Fatty acid and cholesterol composition of the uterine artery intima in relation to menopausal status, age, and serum cholesterol.

Objectives: Estrogens modulate lipid metabolism and the increased risk of atherosclerosis in postmenopausal women is at least partly due to the reduction of estrogen production after menopause. We studied the effect of menopause on the contents of long-chain fatty acids, free cholesterol (FC) and cholesterol ester (CE) in uterine artery wall.

Methods: The uterine artery intima samples were obtained in connection with surgery of 21 postmenopausal and 51 premenopausal women. The amount of FC, CE and phospholipid fatty acids were measured by gas chromatography after extraction and fractionation and these lipid values were related to menopausal status, age and serum total and low-density lipoprotein (LDL) cholesterol levels.

Results: Premenopausal females had significantly less intimal FC (161 +/- 50 vs. 407 +/- 276 microg/100 mg wet weight, P = 0.003) and CE (19 +/- 34 vs. 305 +/- 348 microg/100 mg wet weight, P = 0.050) and smaller proportion of linoleic acid out of all phospholipid fatty acids (4.2 vs. 7.2%, P = 0.002) than postmenopausal women after adjustment with age. The content of CE (r = 0.34, P = 0.025) and the FC-to-CE ratio (r = -0.45, P = 0.002) correlated with age in premenopausal but not in postmenopausal women. Moreover, the intimal content of CE correlated with the percentage of intimal phospholipid linoleic acid in postmenopausal women (r = 0.79, P = 0.020). The same was true for FC (r = 0.73, P < 0.001).

Conclusions: These results indicate that CE and FC accumulation into the wall of uterine artery depends on menopausal status, independently of age, and that the phospholipid long-chain fatty acid composition differs significantly between premenopausal and postmenopausal women. This suggests that estrogens may be involved in the regulation of artery wall lipid composition.