OXIDIZED LIPIDS IN THE DIET ACCELERATE THE DEVELOPMENT OF FATTY STREAKS IN CHOLESTEROL-FED RABBITS

Studies have indicated that oxidized lipoproteins may play a role in a therosclerosis. We have recently demonstrated that the levels of oxidi zed lipoproteins in the circulation can be directly correlated to the quantity of oxidized lipids in the diet. The present study tested the hypothesis that dietary oxidized lipids accelerate the development of atherosclerosis. For 12 to 14 weeks, 36 male New Zealand White rabbits were fed a low-cholesterol (0.25%) diet containing either 5% unoxidiz ed corn oil (control diet) or 5% oxidized corn oil (oxidized-lipid die t). Serum cholesterol levels increased to a similar extent in both gro ups, with the majority of the cholesterol in the beta-migrating very l ow density lipoprotein (beta-VLDL) fraction. beta-VLDL from control an imals contained 3.86 +/- 0.57 versus 9.07 +/- 2.14 nmol conjugated die nes per mu mol cholesterol (P<.05) in rabbits fed the oxidized-lipid d iet. No difference in oxidized lipid levels was detected in LDL. Most important, feeding a diet rich in oxidized lipid resulted in a 100% in crease in fatty streak lesions in the aorta. Additionally, rabbits tha t were fed the oxidized-lipid diet had a >100% increase in total chole sterol in the pulmonary artery that was primarily due to an increase i n cholesteryl ester. Oxidized lipids are frequently present in the typ ical US diet, and our results suggest that consumption of these foods may be an important risk factor for atherosclerosis.