Lipoprotein and apolipoprotein profile in children with primary nephrotic syndrome: Metabolic alterations and consequences.

Serum levels of lipoprotein and apolipoprotein from 50 children, aged between 2 and 16 years, were measured by the enzymatic method and by immunoturbidimetric assay respectively, to determine abnormalities of lipid metabolism during the course of primary nephritic syndrome. There was a highly significant correlation between serum levels of both total cholesterol and low density lipoprotein cholesterol (LDL-C) and those of apolipoprotein B (apo B) (n=114, r=0.946, p<0.001 and n=99, r=0.943, p<0.001, respectively) and, to a lesser extent, between serum high density lipoprotein cholesterol (HDL-C) and apolipoprotein A-I (apo A-I) levels (n=123, r=0.679, p<0.001). HDL-C levels of apo A-I did not exhibit an association with those of albumin. The ratio of HDL-C to apo A-I, on the other hand, was low (<1.0) at very low levels of serum albumin (<2.0 g/dI) but showed a gradual rise with increasing albumin levels. These results may indicate a compositional change in HDL particles in the clinical course of nephritic syndrome, with a relatively high level of apolipoprotein-rich HDL particle (HDL)3 at very low albumin levels and predominantly HDL2 particles, which contain relatively more cholesterol, at increasing levels of albumin. Serum levels of LDL-C and apo B correlated significantly and inversely with serum albumin levels (n=101, r=-0.836, p<0.001 and n=114, r=-0.825, p<0.001, respectively). Compared with levels from healthy control children (2.52+0.67 mmol/L (97+26 mg/dI) and 0.86+0.21 g/L) matched for age and serum albumin levels, however, a relatively high concentration of both parameters of 3.59+1.02 mmol/L (139+40 mg/dI) and 1.47+0.32 g/L, respectively, was still observed at high serum albumin levels (> 4 g/dI). The finding of a persistance of abnormalities in lipid profile, despite a response to treatment of nephritic syndrome, may have some prognostic significance and should been given therapeutic consideration in the long-term management of children with primary nephrotic syndrome.