Gender differences in response to a hypercholesterolemic diet in hamsters:effects on plasma lipoprotein cholesterol concentrations and early aortic atherosclerosis

Gender is a strong predictor of coronary heart disease (CHD) susceptibility and reports indicate that males are more likely to develop CHD compared to age-matched premenopausal females. To lest whether similar gender differen ces exist in hamsters, 16 male and 16 female F1B Golden Syrian hamsters, ag ed 10 weeks, were fed a hypercholesterolemic nonpurified diet (HCD) contain ing 10% coconut oil and 0.05% cholesterol for 12 weeks. Plasma lipid and li poprotein cholesterol concentrations, LDL oxidative susceptibility, LDL toc opherol concentrations, LDL fatty acid composition, LDL particle size, plas ma estradiol and testosterone concentrations, and early aortic atherosclero sis were analyzed. Female hamsters had significantly lower plasma total cho lesterol and nonhigh-density lipoprotein cholesterol (nonHDL-C) and greater high-density lipoprotein cholesterol (HDL-C) concentrations compared to ma le hamsters (- 15, - 33, and 33%; respectively). Female hamsters had signif icantly greater LDL particle size (4%), LDL 22:6 (21%) fatty acid, and rare of LDL oxidation (34%) compared to male hamsters. Female hamsters had a si gnificantly higher concentration of plasma estradiol (49%) compared to male hamsters. Female hamsters also had significantly less early aortic atheros clerosis compared to male hamsters (- 77%). In female hamsters, aortic fatt y streak formation was significantly associated with plasma nonHDL-C (r = 0 .76, P < 0.0007), LDL particle size (r = - 0.66, P < 0.005), plasma TC (r = 0.68, P < 0.004), and lag phase of LDL oxidation (r = 0.84, P < 0.02). In male hamsters, aortic fatty streak formation was significantly associated w ith plasma nonHDL-C (r = 0.52, P < 0.04), plasma TC (r = 0.55, P < 0.03), p lasma TG (r = 0.79, P < 0.0003), and LDL 22:6 (r = - 0.78, P < 0.03) with n o association with any measures of LDL oxidation susceptibility. This study demonstrates that female hamsters have an improved plasma lipoprotein chol esterol profile, larger LDL particle size, and less early aortic atheroscle rosis compared to male hamsters fed the same HCD. (C) 1999 Elsevier Science Ireland Ltd. All rights reserved.