Lipoprotein distribution and composition in the human nephrotic syndrom

Abstract

Plasma lipoprotein profiles were quantitated in 9 patients with the nephrotic syndrome. Six subjects were studied both during an active proteinuric phase and during a remission phase without proteinuria. During the proteinuric phase, the plasma triglyceride, cholesterol and apo B levels were markedly increased, whereas the HDL cholesterol, apo A-I, and apo A-II concentrations were normal. Analysis of the distribution and composition of the lipoprotein subclasses, separated by isopycnic ultracentrifugation, showed typical patterns characterized by: (1) elevated apo B-rich VLDL and LDL fractions, (2) the presence of a denser LDL subfraction, floating at d 1.053 g/ml, which contained about 35% of LDL cholesterol and apo B and (3) a redistribution among HDL subclasses. The HDL 2b (d 1.063–1.100 g/ml) fraction was markedly decreased, while the HDL2a+3a (d 1.100–1.150 g/ml) and HDL 3b + 3c ( d 1.150–1.210 g/ml) subclasses were moderately elevated. The decreased cholesterol and apo A-I contents of HDL 2b therefore counterbalanced their increase in HDL2a+3a and HDL 3b + 3c, resulting in normal plasma HDL cholesterol and apo A-I concentrations. When reinvestigated during a remission phase without proteinuria, the nephrotic patient's overall lipoprotein distribution and composition were similar to those in healthy controls. The combination of several factors such as the presence of elevated apo B-rich VLDL, IDL and LDL, together with decreased HDL 2 cholesterol and HDL 2 apo A-I suggests that nephrotic patients are at increased risk for atherosclerosis.