COPPER-INDUCED LIPID OXIDATION IN UNFRACTIONATED PLASMA - THE LAG PRECEDING OXIDATION AS A MEASURED OF OXIDATION-RESISTANCE

In spite of the pathological significance of oxidation of plasma lipid s, no method is currently available for the evaluation of the suscepti bility of these lipids to oxidation in unfractionated plasma. Here we demonstrate that copper-induced oxidation of diluted plasma, in the pr esence of citrate can be monitored continuously by recording the absor bance at 245nm. The kinetics of accumulation of oxidation products in unfractionated plasma is a sum of lipid oxidation products obtained in low and high density lipoproteins isolated from the same plasma. The kinetic profiles are reproducible and can be performed with plasma sam ples even after prolonged storage at 4 degrees C (up to two months) or after freezing and thawing of the plasma. Being simple and reproducib le, yet correlating with the oxidizability of low and high density lip oproteins, this method can be used to evaluate the ''oxidation resista nce'' of plasma lipids and thus serve as a standard index of the susce ptibility of the plasma lipids of patients to oxidation-inflicted path ologies, including atherosclerosis. (C) 1995 Academic Press, Inc.