COMPARATIVE-STUDY OF THE ACTIVITY AND COMPOSITION OF HDL(3) IN RUSSIAN AND AMERICAN MEN

Previous studies conducted within the framework of the Lipid Research Clinics Program showed a strong inverse correlation between high-densi ty lipoprotein cholesterol (HDL-C) level and coronary heart disease (C HD) risk in American male populations, whereas in Russian populations such a correlation was less pronounced. It was assumed that HDL was le ss protective of CHD in Russian than in American males. This study com pared the functional activity and lipid composition of HDL(3) isolated from the blood plasma of men with low, normal, and high HDL-C levels from Moscow (Russia) and Seattle (United States) populations. Results obtained showed that American HDL(3), irrespective of the plasma HDL-C level, had higher activity in stimulating both [H-3]cholesterol and c holesterol mass efflux from cholesterol-loaded fibroblasts and in supp ressing cellular cholesterol esterification when compared with Russian HDL(3). American HDL(3) remained more active than Russian HDL(3), eve n when apolipoprotein E-containing particles were removed from HDL(3) by heparin-Sepharose affinity chromatography. Russian and American I-1 25-HDL(3) had similar binding to high-affinity cell-surface sites, but Russian HDL(3) had a higher nonspecific binding component compared wi th American HDL(3). This study demonstrates for the first time potenti al functional differences between HDL particles isolated from Russian and American populations. The lower activity of Russian HDL(3) in prom oting cellular cholesterol efflux may partly explain the higher CHD ri sk in the Russian population compared with the American one.