Effect of HDL composition and particle size on the resistance of HDL to the oxidation

OBJECTIVES: To study the resistance of HDL particles to direct oxidation in respect to the distribution of HDL particles. DESIGN AND METHODS: We studied HDL composition, subclass distribution, and the kinetics of CuSO(4)-induced oxidation of total HDL and HDL(3 )in vitro in 36 low-HDL-C subjects and in 41 control subjects with normal HDL-C. RESULTS: The resistance of HDL(3 )to oxidation, as assessed from the propagation rate was significantly higher than that of total HDL. The propagation rate and diene formation during HDL oxidation in vitro was attenuated in HDL derived from low-HDL-C subjects. Propagation rate and maximal diene formation during total HDL oxidation correlated significantly with HDL mean particle size. The propagation rate of total HDL oxidation in vitro displayed a significant positive association with HDL(2 )particle mass and HDL mean particle size by multiple regression analyses. CONCLUSIONS: These observations highlight that the distribution of HDL subpopulations has important implications for the potential of HDL as an anti-oxidant source.