Moderate intake of n-3 fatty acids is associated with stable erythrocyte resistance to oxidative stress in hypertriglyceridemic subjects.

Background The important triacylglycerol-lowering capacity of n-3 fatty acids is counterbalanced by their inherent sensitivity to oxidation. Inconsistent results about the latter have been reported in hypertriglyceridemic individuals. After incorporation into cell membranes, n-3 fatty acids may alter membrane-related functions. In view of the distinct composition of hypertriglyceridemic membranes and the prooxidant status in this condition, it can be surmised that cell enrichment with the oxidizable n-3 fatty acids will be associated with an increased hemolytic process. Objective We sought to evaluate the effect of fish oil consumption on n-3 fatty acid incorporation into erythrocyte membra…

Pro-oxidant effects of 7-hydroperoxycholest-5-en-3β-ol on the copper-initiated oxidation of low density lipoprotein

AbstractIn low density lipoproteins (LDL) supplemented with aged cholesterol and oxidized in the presence of Cu2+, an increase of the lipid oxidation parameters was observed compared with pure cholesterol-enriched LDL. A compound, identified as 7-hydroperoxycholesterol (7HPC), isolated from aged cholesterol and added to LDL, reproduced the above effects. The results indicate that the pro-oxidant effect of 7HPC is dependent on the hydroperoxy group since the corresponding alcohol derivative, 7α-hydroxycholesterol, had no such effect. These data suggest that among the LDL-associated lipid peroxides, cholesterol peroxides may have important implications in the susceptibility of this lipoprotei…

Effect of fish oil on LDL oxidation and plasma homocysteine concentrations in health.

Oxidation of low-density lipoprotein (LDL) and hyperhomocysteinemia are believed to play a role in therogenesis. Whether n-3 polyunsaturated fatty acids increase LDL susceptibility to oxidation or influence homocysteine (Hcy) metabolism has long been a subject of controversy. In this study, we evaluated the effect of 8 weeks of dietary supplementation with 6 g/day of fish oil (FO; 3 g of n-3 fatty acids) on plasma lipoproteins, in vitro LDL peroxidation, antioxidant status, and plasma Hcy concentrations in 16 normolipidemic subjects. FO rapidly and significantly (P < .01) decreased plasma total and very low density lipoprotein triglyceride concentrations and had no effect on LDL or high-den…

Effect of exercise training on in vitro LDL oxidation and free radical-induced hemolysis: the HERITAGE Family Study.

Oxidant stress and overproduction of reactive oxygen species (ROS) contribute to the development of cardiovascular disease. Oxidative modifications of low-density lipoproteins (LDL) are thought to play an early and critical role in atherogenesis. LDL oxidation can be reproduced in vitro, but results usually show a large interindividual variation not entirely explained by the environment. Free radical-induced hemolysis is also proposed to reveal the overall antioxidant capacity. The roles of genetic factors and exercise on the variability of both measures were investigated. The study was conducted in 146 healthy individuals from 28 families participating in a 20-week exercise-training progra…

Involvement of Oxysterols and Lysophosphatidylcholine in the Oxidized LDL–Induced Impairment of Serum Albumin Synthesis by HEPG2 Cells

Abstract —Oxidized low density lipoproteins (Ox-LDLs) are increasingly thought to be a key element in atherogenesis. We have previously reported that serum albumin has important antioxidant properties and that a reduced synthesis of albumin may represent a crucial point in the overall antioxidant defense. In the present work, we aimed at determining whether Ox-LDL could modulate albumin synthesis in cultured human hepatocytes (HepG2 cells). With the use of enzyme immunoassay and radiolabeled leucine incorporation followed by specific immunoprecipitation, Ox-LDL was found to lead to a dose-dependent decrease in albumin secretion. Moreover, the protein synthesis and mRNA levels were decrease…

Consommation de pommes de terre et risques de maladie cardiovasculaire

Resume Les atouts de la pomme de terre declinee sous ses nombreuses formes, auxquels s’ajoutent ses qualites nutritives et son faible cout, expliquent sa consommation importante en Occident. Il apparait indispensable de reflechir a la place et au role tenu par la pomme de terre dans le cadre d’un regime alimentaire sain, au vu de l’incidence croissante des maladies cardiometaboliques comme l’atherosclerose, l’obesite et le diabete, tres liees a l’alimentation et au mode de vie. Il est delicat, dans le cadre d’etudes menees sur l’homme, de distinguer le role specifique d’un aliment de base par rapport a un autre. Des travaux indiquent toutefois que les pommes de terre possedent des propriete…

Enhanced susceptibility of cholesteryl sulfate-enriched low density lipoproteins to copper-mediated oxidation

AbstractCholesteryl sulfate (CS) is a minor component of cell membranes, also present in lipoproteins, and its exact function is unknown. Since oxidation of low density lipoproteins (LDL) is thought to be an important determinant of atherogenesis, we investigated the influence of CS enrichment on copper-mediated oxidation of LDL. CS was found to act as a pro-oxidant, as measured by lipid oxidation parameters. The results also suggest that these effects were dependent on the sulfate group since pure cholesterol or cholesteryl acetate did not promote Cu2+-mediated oxidation. Our findings imply that CS may affect the oxidizability and hence the potential atherogenicity of LDL.

Potential role of oxysterols and lysolecithin in the oxidised LDL-induced decrease in albumin synthesis in HEPG2 cells

Oxidative stress leads to cholesterol accumulation in vascular smooth muscle cells.

The transformation of macrophages and smooth muscle cells into foam cells by modified low-density lipoproteins (LDL) is one of the key events of atherogenesis. Effects of free radicals have mainly been studied in LDL, and other than toxicity, data dealing with direct action of free radicals on cells are scarce. This study focused on the direct effects of free radicals on cholesterol metabolism of smooth muscle cells. A free radical generator, azobis-amidinopropane dihydrochloride, was used, and conditions for a standardized oxidative stress were set up in vascular smooth muscle cells. After free radical action, the cells presented an accumulation of cholesterol that appeared to be the resul…

Treat-to-target versus dose-adapted statin treatment of cholesterol to reduce cardiovascular risk

Clinical guidelines should be based on the best available evidence and are of great importance for patient care and disease prevention. In this respect, the 2013 American College of Cardiology/American Heart Association report is highly appreciated and well-recognized. The report included critical questions concerning hypercholesterolaemia, but its translation into a clinical guideline initiated intense debate worldwide because of the recommendation to switch from a treat-to-target approach for low-density-lipoprotein-cholesterol to a statin dose-based strategy.

Differential effects of oxidized LDL on apolipoprotein AI and B synthesis in HepG2 cells

Oxidized low-density lipoproteins (Ox-LDL) are key elements in atherogenesis. Apolipoprotein AI (apoAI) is an active component of the antiatherogenic high-density lipoproteins (HDL). In contrast, plasma apolipoprotein B (apoB), the main component of LDL, is highly correlated with coronary risk. Our results, obtained in HepG2 cells, show that Ox-LDL, unlike native LDL, leads to opposite effects on apoB and apoAI, namely a decrease in apoAI and an increase in apoB secretion as evaluated by [(3)H]leucine incorporation and specific immunoprecipitation. Parallel pulse-chase studies show that Ox-LDL impaired apoB degradation, whereas apoAI degradation was increased and mRNA levels were decreased.…