Plasma concentration and urinary excretion of erythropoietin in adult nephrotic syndrome

Abstract

purpose: Nephrotic syndrome (NS) is associated with a significant alteration of protein metabolism. While lowering the plasma concentrations of certain proteins, the disease often raises the level of certain other proteins. The current study was undertaken to determine the effect of NS on erythropoietin (EPO) metabolism. patients and methods: We measured the EPO concentration in plasma and urine of 26 patients with NS by an immunologic assay using a rabbit antiserum against recombinant human EPO. The results were compared with those obtained in a group of 12 normal control subjects. results: Despite a significant reduction in the hemoglobin concentration in the NS group compared with the control group (125 ± 25 g/L versus 148 ± 11 g/L, p <0.05), the plasma EPO concentration in the NS group was not significantly different from that seen in the control group (6.2 ± 4.5 mU/mL versus 6.7 ± 2.4 mU/mL, p = NS). No significant correlations were found between plasma EPO and hemoglobin concentration, serum creatinine, serum albumin, or urinary albumin excretion rate. Moreover, comparison of the NS patients with serum creatinine concentrations less than or equal to 1.5 mg/dL (133 μmol/L) with those exhibiting creatinine concentrations exceeding 1.5 mg/dL did not reveal a significant difference in mean plasma EPO concentration. Significant amounts of EPO were found in the urine of the patients with NS, while none was detected in the urine of the control subjects. conclusion: We conclude that plasma EPO is inappropriately low in patients with NS. This is due, at least in part, to the urinary/renal losses of this protein and can potentially contribute to anemia in NS patients or compound the problem in those with concurrent renal insufficiency and diminished EPO production.