Isoprostane levels in lipids extracted from atherosclerotic arteries of nonhuman primates

Nonhuman primates used in these studies had been fed for 5 years diets enriched with cholesterol and one of three classes of fatty acids: saturated, monounsaturated, or polyunsaturated fatty acids. Atherosclerotic iliac artery lipid extracts were quantitatively analyzed for cholesterol, cholesteryl esters, fatty acid composition, and a marker of lipid oxidation, the F₂-isoprostanes. There was no significant difference in the mean accumulation of F₂-isoprostanes among the different diet groups. To account for the small, individual variation in the arachidonate concentration the F₂-isoprostane mass from each sample was normalized by dividing by arachidonate mass: F₂-isoprostane mass/(mass arachidonate). At lower levels of cholesterol accumulation, the F₂-isoprostane mass/(mass arachidonate) ratio was greater in lipids from POLY arteries compared to SAT arteries, but the reverse was true at high levels of cholesterol. F₂-isoprostane/(mass arachidonate) increased with mole fraction linoleate for the SAT group, but decreased for the POLY group. In summary, these studies demonstrated that there is no simple explanation of how F₂-isoprostane accumulation did not depend on the concentration of oxidizable lipids that promote free-radical lipid oxidation.