VERY-LOW-DENSITY LIPOPROTEINS AND SUBCLAS SES OF INTERMEDIATE DENSITYLIPOPROTEINS IN POSTMENOPAUSAL WOMEN

Post menopausal women present an increase of cardiovascular risk assoc iated with the atherogenic plasma lipoproteins IDL and LDL. Our purpos e was to study the composition of VLDL, IDL and the subfractions IDL-1 and IDL-2, and the Lipoprotein Lipase and Hepatic Lipase activities i n a group of twelve healthy post menopausal women as compared with ele ven fertile controls. The mean values of total cholesterol and LDL cho lesterol were significantly increased in the post menopausal group com pared to the controls (p < 0.005 and p < 0.001 respectively). The cont ribution of the HDL-cholesterol plasma concentration to total choleste rol was lower in the postme-nopausal women (p < 0.02) although no one had HDL-cholesterol lower than 35 mg/dl and the mean value was 50 mg/d l. Postmenopausal women had increased concentrations of VLDL, total ID L and IDL-2 compared to controls (p < 0.05, p < 0.005 and p < 0.001 re spectively). Plasma concentrations of total IDL was increased in postm enopausal women (33.6 +/- 3.4 vs 22.6 +/- 0.8 mg/dl, p < 0.005). The i ncrease in total IDL was due to IDL-2 (19.9 +/- 1.7 vs 11.5 +/- 0.8 mg /dl, p < 0.001, in postmenopausal women vs controls). The IDL-2 subfra ction was 60 +/- 2.6% of total IDL in postmenopausal women and 51 +/- 2.0% in controls (p < 0.02). In postmenopausal women and in controls t he ratio triglyceride/protein (which indicates particles size) was sig nificantly higher in IDL-1 than in IDL-2 (p < 0.005 and p < 0.01 respe ctively), but this ratio did not show differences when VLDL, total IDL and IDL-2 were compared between postmenopausal and control women. The n, the increased plasma concentration of these lipoproteins would show an increased number of particles in the postmenopausal women vs contr ols. There were no differences in the Lipoprotein Lipase and Hepatic L ipase activities between both groups. Lipoprotein Lipase vs total IDL- triglycerides and IDL-2-triglycerides showed a significant inverse cor relation in controls (p < 0.05) but not in postmenopausal women. We co nclude that the qualitative and quantitative study of the lipoproteins shows a more atherogenic profile in the postmenopausal group, with an increase in the concentration and number of particles of VLDL, total IDL and IDL-2.