Relation of hyperlipidemia in serum and loss of high density lipoproteins in urine in the nephrotic syndrome.

The mechanism leading to hyperlipidemia in the nephrotic syndrome is not fully understood but may be related in part to loss of high density lipoproteins in the urine of patients with nephrosis. To prove this hypothesis, we compared serum lipoprotein profiles with the excretion of high density lipoproteins in urine in 19 nephrotic patients. Serum cholesterol ranged from 19-152 (median value 45) mg/dl in very low density lipoproteins (VLDL), from 130-443 (median 186) mg/dl in low density lipoproteins (LDL) and from 19-64 (median 33) mg/dl in high density lipoproteins (HDL). Hyperlipoproteinemia was found in 17 patients, which was classified as phenotype IIa (Fredrickson) in 2, as phenotype IIb in 9 and as phenotype IV in 6 subjects. Two patients showed normal lipoprotein patterns. VLDL- and LDL-cholesterol were not found in detectable amounts in urine, whereas HDL-cholesterol was measured in low concentrations from 0.1-8.3 mg/24 h in all samples. There was no correlation between serum HDL-cholesterol and urinary HDL-cholesterol, but a positive correlation between serum LDL-cholesterol and urinary HDL-cholesterol (r = +0.54, p less than 0.05). However, the total amount of the daily urinary loss of HDL (less than 1% of total plasma HDL) seems not to be sufficient to explain hyperlipoproteinemia in the nephrotic syndrome.