ELEVATED PLASMA-LIPID HYDROPEROXIDES IN PATIENTS WITH CORONARY-ARTERYDISEASE

Sustained presence of lipid peroxides in the circulation and their pla sma carrier is a controversial issue. Particularly, there is no firm e vidence for an increased plasma lipid peroxide level in patients with atherosclerosis. In this study, a strong correlation was found between plasma total lipid hydroperoxide and lipid hydroperoxide content of I DL cholesterol (r = 0.882; p < 0.001; n = 16). Lipid hydroperoxides in plasma were carried almost exclusively (89%) in LDL. In 70 patients t ested 3 months after coronary artery bypass graft surgery with a speci fic assay, plasma lipid hydroperoxide levels were significantly increa sed when compared with matched healthy controls (4.31 +/- 0.23 nmol/ml and 2.34 +/- 0.13 nmol/ml, p < 0.0001, patients vs controls, respecti vely). These concentrations are 10 times lower than those detected by the nonspecific thiobarbituric acid assay. However, considering the in vitro concentration range in which oxidized IDL exerts important athe rogenic effects, the elevated plasma lipid hydroperoxide levels measur ed in atherosclerotic patients have pathologic significance.