LIPID PEROXIDE LEVELS IN TYPE-II HYPERLIPOPROTEINEMIC SUBJECTS

The purpose of this study was to evaluate, under the most rigorous pre cautionary measures against in vitro oxidation, whether the baseline l ipid peroxide levels in hypercholesterolemic subjects were higher than those in normolipidemic subjects. Two methods were employed: thiobarb ituric acid (TBA), and hemoglobin-methylene blue (HbMB). Blood was col lected into EDTA tube and centrifuged at 4-degrees-C for 30 min to col lect plasma, then protected from in vitro oxidation with preservatives and N2. Serum was from blood samples allowed to clot at 20-degrees-C for 1 h, then protected from oxidation. Determination of lipid peroxid e was carried out within 2 h of blood collection. Results from 35 hype rcholesterolemic and 34 control subjects showed that lipid peroxide le vels obtained from both methods were significantly higher in serum tha n in plasma for both groups, suggesting a greater rate of lipid peroxi dation occurred in serum during clot formation. However, no significan t difference in lipid peroxide levels was found between patients and c ontrols in either serum or plasma by either assay method. No correlati on existed between lipid peroxide values and plasma cholesterol or LDL -cholesterol levels. These results suggest that the mechanism for a hi gher tendency towards atherosclerosis in hypercholesterolemic subjects is not related to baseline levels of plasma lipid peroxide.