PROTEIN AND LIPID-METABOLISM IN NEPHROTIC INFANTS ON PERITONEAL-DIALYSIS AFTER NEPHRECTOMY

Congenital nephrotic syndrome of the Finnish type (CNF) is associated with protein deficiency despite substantial protein supplementation in the nephrotic state before nephrectomy. Different protein intakes (2.5 vs. 3.7 g/kg per day) in hypoproteinaemic children on continuous cycling peritoneal dialysis (CCPD) were studied. Lipids were also measured to determine whether severe atherogenic abnormalities seen during nephrosis improved after nephrectomy. Growth was normal or became normal with both protein intakes. Serum pre-albumin and transferrin concentrations became normal. Total protein (57 +/- 3.0 vs. reference limits 60 - 75 g/l) and albumin (28 +/- 5.0 vs. reference limits 30-50 g/l) concentrations improved but remained below normal, even with the higher protein intake. Muscle mass determined by measuring femoral quadriceps muscle thickness using ultrasound was markedly reduced in all patients at nephrectomy. It improved (P < 0.05) in all but 2 patients who had several bacterial infections, but reached normal level in only 3 patients within 6 months. Plasma total, very low-density lipoprotein (VLDL) and low-density lipoprotein (LDL) triglyceride concentrations decreased (P < 0.05, P < 0.05 and P < 0.01, respectively) and VLDL, LDL and high-density lipoprotein (HDL) particles contained less triglyceride than in the nephrotic state. HDL cholesterol concentrations increased by 28% [0.58 +/- 0.22 mmol/l during nephrosis, 0.81 +/- 0.21 mmol/l on CCPD after nephrectomy (P < 0.05)] but remained below the level of 1.38 +/- 0.75 mmol/l in normal controls (P < 0.001). If compared with controls there were still significant abnormalities in lipoprotein concentrations on CCPD. Hence, a protein intake of 2.5 g/kg per day representing 140% of the recommended dietary allowance is sufficient to maintain normal growth and improve nutritional and protein status in CNF patients on CCPD. Although lipid levels improved they remained abnormal.