13-hydroperoxy-9-11-octadecadienoic-acid and 9-hydroxy-10-12-octadecadienoic-acid

To determine in vivo if L-4F differentially alters plasma levels of oxidized fatty acids resulting in more anti-inflammatory HDL. Injecting L-4F into apoE null mice resulted in a significant reduction in plasma levels of 15-HETE, 5-HETE, 13-HODE and 9-HODE. In contrast, plasma levels of 20-HETE were not reduced and plasma levels of 14,15-EET, which are derived from the cytochrome P450 pathway, were elevated after injection of L-4F. Injection of 13(S)-HPODE into wild-type C57BL/6J mice caused an increase in plasma levels of 13-HODE and 9-HODE and was accompanied by a significant loss in the anti-inflammatory properties of HDL. The response of atherosclerosis resistant C3H/HeJ mice to injection of 13(S)-HPODE was similar but much more blunted. Injection of L-4F at a site different from that at which the 13(S)-HPODE was injected resulted in significantly lower plasma levels of 13-HODE and 9-HODE and significantly less loss of HDL anti-inflammatory properties in both strains. i) L-4F differentially alters plasma levels of oxidized fatty acids in vivo. ii) The resistance of the C3H/HeJ strain to atherosclerosis may in part be mediated by a reduced reaction of this strain to these potent lipid oxidants.

Topics: 8,11,14-Eicosatrienoic Acid; Animals; Anti-Inflammatory Agents; Apolipoproteins E; Atherosclerosis; Chromatography, Liquid; Enzyme-Linked Immunosorbent Assay; Fatty Acids; Female; Hydroxyeicosatetraenoic Acids; Injections, Subcutaneous; Linoleic Acids; Linoleic Acids, Conjugated; Lipid Peroxides; Lipoproteins, HDL; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Mice, Knockout; Oxidation-Reduction; Peptides; Species Specificity; Tandem Mass Spectrometry; Time Factors; Up-Regulation

Low density lipoprotein that was oxidized by activated human monocytes was analyzed to determine the identity of oxidized fatty acids present and the conditions required for their formation. The oxidized lipids were also analyzed under conditions allowing preservation of their oxidation state. Using reversed-phase high performance liquid chromatography (HPLC) analysis of native and saponified lipid extracts of oxidized low density lipoprotein (LDL), we found that the major fatty acid oxidation product was esterified hydroperoxyoctadecadienoic acid (HPODE), the oxidized product of the most abundant polyunsaturated fatty acid in human LDL, linoleic acid. Although some esterified hydroxyoctadecadienoic acid (HODE) was also detected, the reduction of HPODE to HODE did not appear to be monocyte-dependent. Essentially all of the HPODE was found to be esterified with the majority being esterified to cholesterol followed by phospholipids and generally following the abundance of esterified linoleic acid within the lipid classes. The percent of cholesteryl linoleate converted to cholesteryl HPODE and cholesteryl HODE at the end of the 24-h incubation was determined to be approximately 13.5%. The formation of oxidized esterified linoleic acid in the LDL was shown to require immunological activation of the human monocytes, a previously observed requirement for general LDL oxidation in this culture system. The oxidized esterified linoleic acid was present in the supernatant with the LDL and was not cell-associated. HPODE formation on LDL was prevented by including superoxide dismutase (SOD) or eicosatetraynoic acid (ETYA) during the 24-h coincubation of activated monocytes with LDL whereas indomethacin was without effect. The analysis of the lipid oxidation products in oxidized LDL can provide insight into the mechanisms involved in oxidation of LDL by activated human monocytes.

Topics: Cholesterol Esters; Esterification; Humans; Hydroxyeicosatetraenoic Acids; In Vitro Techniques; Kinetics; Linoleic Acids; Linoleic Acids, Conjugated; Lipid Peroxides; Lipoproteins, LDL; Monocytes; Oxidation-Reduction; Thiobarbituric Acid Reactive Substances