Time course of oxysterol formation during in vitro oxidation of low density lipoprotein

✍ Scribed by Susanna Dzeletovic; Amir Babiker; Erik Lund; Ulf Diczfalusy

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 769 KB
• Volume: 78
• Category: Article
• ISSN: 0009-3084
• DOI: 10.1016/0009-3084(95)02489-6

✦ Synopsis

Cholesterol oxidation products (oxysterols) have been implicated in several aspects of atherogenesis; they affect key enzymes in cholesterol homeostasis, induce calcification in vascular cells and possess cytotoxic properties. Oxysterols are formed during oxidative modification of low density lipoprotein (LDL). Using a recently developed method based on isotope dilution-mass spectrometry, the kinetics of formation of oxysterols during oxidation of LDL by cupric ions or soybean lipoxygenase was studied. The same products, mainly 7-and 5-oxygenated cholesterol, were formed by the two oxidation methods. Virtually no side-chain oxidized oxysterols were formed. During the oxidations, preferentially esterified cholesterol was consumed and consumption of polyunsaturated fatty acids and formation of conjugated dienes preceded the appearance of oxysterols. Cholesterol 7-hydroperoxides potential cytotoxins, were present in LDL oxidized by copper or lipoxygenase.