Oxidized low-density lipoprotein

Abstract

Oxidized low-density lipoprotein (Ox-LDL) has been studied for over 25 years. Numerous pro- and anti-atherogenic properties have been attributed to Ox-LDL. Yet, Ox-LDL has neither been defined nor characterized, as its components and composition change depending on its source, method of preparation, storage, and use. It contains unoxidized and oxidized fatty acid derivatives both in the ester and free forms, their decomposition products, cholesterol and its oxidized products, proteins with oxidized amino acids and cross-links, and polypeptides with varying extents of covalent modification with lipid oxidation products, and many others. It seems to exist in vivo in some form not yet fully characterized. Until its pathophysiological significance, and how it is generated in vivo are determined, the nature of its true identity will be only of classical interest. In this review, its components, their biological actions and methods of preparation will be discussed.

Figures

Fig. 24.1

Forms of oxidized low-density lipoprotein (reproduced from Parthasarathy et al. (157)). (a)Unoxidized native LDL with amino groups of lysine residues of apo B and representative lipids. (b) Lipid peroxides generated elsewhere associated with such LDL. (c) LDL lipids might get oxidized resulting in the generation of cholesterol ester and phospholipid peroxides. (d) Such LDL might undergo extensive oxidation leading to protein changes. (e) Extensive protein changes and lipid decomposition might hallmark the end stages of oxidation.

Fig. 24.2

Number of publications related to Ox-LDL.