Oxidized Lipids in the Diet Accelerate the Development of Fatty Streaks in Cholesterol-Fed Rabbits

Abstract

Studies have indicated that oxidized lipoproteins may play a role in atherosclerosis. We have recently demonstrated that the levels of oxidized 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% unoxidized corn oil (control diet) or 5% oxidized corn oil (oxidized-lipid diet). Serum cholesterol levels increased to a similar extent in both groups, with the majority of the cholesterol in the beta-migrating very low density lipoprotein (beta-VLDL) fraction. Beta-VLDL from control animals contained 3.86+/- 0.57 versus 9.07 +/- 2.14 nmol conjugated dienes per micromol cholesterol (P<.05) in rabbits fed the oxidized-lipid diet. No difference in oxidized lipid levels was detected in LDL. Most important, feeding a diet rich in oxidized-lipid resulted in a 100% increase in fatty streak lesions in the aorta. Additionally, rabbits that were fed the oxidized-lipid++ diet had a >100% increase in total cholesterol in the pulmonary artery that was primarily due to an increase in cholesteryl ester. Oxidized lipids are frequently present in the typical US diet, and our results suggest that consumption of these foods may be an important risk factor for atherosclerosis.

Consumption of Repeatedly Heated Soy Oil Increases the Serum Parameters Related to Atherosclerosis in Ovariectomized Rats

“…Several studies have demonstrated the adverse effects of oxidized dietary fats on human and experimental animals; namely, consumption of oxidized oil caused liver dysfunction (Hayam et al 1995;Owu et al 1998) and was responsible for development of fatty streaks (Staprans et al 1996;Hur et al 2005).…”

Oxidized Cholesterol in the Diet Accelerates the Development of Aortic Atherosclerosis in Cholesterol-Fed Rabbits

“…To facilitate comparison with our previous study, which demonstrated that oxidized fatty acids in the diet accelerate atherosclerosis, 7 in this study we used a similar experimental protocol. Twenty-six 10-to 11-week-old male New Zealand White rabbits (2 kg initial weight) were divided into two equal groups and were individually housed in stainless steel cages at the San Francisco Veterans Affairs Animal Housing.…”

“…5 Most importantly, we recently have demonstrated that oxidized lipids in the diet are atherogenic. 7 We have shown that feeding a diet enriched in oxidized fatty acids to cholesterol-fed rabbits resulted in a significant increase in fatty streak lesions in the aorta. These results demonstrate for the first time that diets containing oxidized fatty acids accelerate atherosclerotic lesions.…”

The effect of meals rich in thermally stressed olive and safflower oils on postprandial serum paraoxonase activity in patients with diabetes

“…Furthermore, cooking with vegetable oils rich in MUFA would be expected to result in lower levels of lipid oxidation products compared with oils rich in PUFA (Grootveld et al, 1998;Kritchevsky & Tepper, 1967). Vegetable oils rich in PUFA are vulnerable to oxidation during heating in air and diets rich in oxidised PUFA increase levels of lipid oxidation products in human chylomicrons (Staprans et al, 1999) and accelerate the development of experimental atherosclerosis (Staprans et al, 1996). Also, animal studies have indicated that secondary lipid oxidation products from PUFA-rich oils are absorbed from the gut and inhibit hepatic enzyme activities (Kanazawa & Ashida, 1991).…”