Simple and rapid assessment of lipoprotein susceptibility to oxidation in the macromolecule fraction of plasma

Abstract

Background: Susceptibility of lipoprotein to oxidation is usually studied using purified lipoproteins. However, for large clinical studies or routine clinical assessment, a rapid, less time-consuming method that minimizes hydroperoxide accumulation in lipoprotein during preparation is desirable. Methods using whole plasma are complicated by the presence of an anticoagulant that may affect oxidation and the presence of antioxidants in the plasma aqueous phase. Lipoproteins in serum are relatively unprotected from initiation of oxidation. Methods: We studied copper-mediated oxidation of a macromolecule fraction of plasma prepared by simple molecular sieve chromatography. Results: LDL was more susceptible to oxidation than plasma macromolecules. The lag times approached zero as the copper concentration increased. The propagation rate was linear for PM vs. the copper concentration while LDL became saturated at 10–20 μmol/l. The interassay CVs for the lag phase rate, lag time, PR and maximal Δ A max were 23%, 7.7%, 4.9%, and 3.3%, respectively. Conclusions: This procedure should be applicable to large numbers of individuals in investigations regarding the effects of drugs and diets on lipid composition and oxidative susceptibility.