Oxidation of LDL in the subendothelial space has been proposed to play a key role in atherosclerosis. Endothelial cells produce superoxide anions (O2 ) and oxidize LDL in vitro; however, the role of O2 .2 in endothelial cell–induced LDL oxidation is unclear. Incubation of human LDL (200 mg/mL) with bovine aortic endothelial cells (BAECs) for 18 hours resulted in a 4-fold increase in LDL oxidati...

Oxidation of low-density lipoprotein (LDL) may play an important role in atherosclerosis. We studied the effects of bicarbonate/CO2 and phosphate buffer systems on metal ion-catalyzed oxidation of LDL to malondialdehyde (MDA) and to protein carbonyl and MetO derivatives. Our results revealed that LDL oxidation in mixtures containing free iron or heme derivatives was much greater in bicarbonate/...

Oxidation of LDL by peroxidases has been suggested to be a model for in vivo oxidation. The mechanism might involve the generation of an intermediate radical such as a phenoxy radical. We show that, in contrast to the oxidation of LDL by copper, oxidation by peroxidase system (H2O2/horse radish peroxidase) showed less resistance. This suggested that either the antioxidants were consumed more ra...

BACKGROUND Although individuals with diabetes mellitus frequently have dyslipidaemias and high blood pressure, much of the increased risk for coronary heart disease is not explained by these and other classical risk factors. Thus, other less widely recognized risk factors, including increased susceptibility of low-density lipoprotein (LDL) to oxidation, might enhance vascular dysfunction and at...

Low-density-lipoprotein (LDL) oxidation may provide the crucial link between plasma LDL and atherosclerotic-lesion formation. Oxidation can be induced in vitro by incubating LDL with cells or metal ions and can be measured by continuously monitoring conjugated-diene absorbance at 234 nm. Measurement of LDL oxidizability was improved by performing the assay with 0.05 g of LDL-protein per liter o...

There is accumulating evidence that LDL oxidation is essential for atherogenesis, and that antioxidants that prevent this oxidation may either slow down or prevent atherogenesis. In the present study, we found that Commiphora mukul and its cholesterol-lowering component, guggulsterone, effectively inhibited LDL oxidation mediated by either catalytic copper ions, free radicals generated with the...

Transgenic mice overexpressing Cu/Zn superoxide dismutase (hSod1Tg(+/0)) or catalase (hCatTg(+/0)) and knockout mice underexpressing manganese superoxide dismutase (Sod2(+/)(-)) or glutathione peroxidase-1 (Gpx1(-/-)) were used to study the effect of antioxidant enzymes on cell-mediated low density lipoprotein (LDL) oxidation and oxidized LDL (oxLDL)-induced apoptosis. Incubation of LDL with mo...

Carotenoids and alpha-tocopherol are dietary, lipophilic antioxidants that may protect plasma lipoproteins from oxidation, a process believed to contribute to atherogenesis. Previous work demonstrated that after the Cu(II)-initiated oxidation of human low density lipoprotein (LDL) in vitro, carotenoids and alpha-tocopherol were destroyed before significant lipid peroxidation took place, and tha...

Peroxidation of low-density lipoprotein (LDL) lipid is generally thought to represent the initial step in a series of modification reactions that ultimately transform the protein moiety of the lipoprotein into a form recognized by receptors different from those that bind native LDL. Uptake of LDL via these alternative receptors can lead to the formation of lipid-laden cells, which are typical f...