Recombinant human insulin-like growth factor-1 induces an anabolic response in malnourished CAPD patients

Background. Insulin-like growth factor-1 (IGF-1) is an anabolic hormone tha t mediates most of the growth effects of growth hormone. This study tested the hypothesis that recombinant human IGF-1 (rhIGF-1) will induce an anabol ic response in malnourished patients undergoing continuous ambulatory perit oneal dialysis (CAPD). Methods. Six CAPD patients. With protein-energy malnutrition underwent nitr ogen balance studies in a clinical research center for 35 days each. Throug hout the study, patients were maintained on their same CAPD regimen prior t o hospitalization, and were fed a constant protein and energy intake that w as similar to their diet prior to hospitalization. The first 15 hospital da ys were a baseline period; during the subsequent 20-day period, patients we re given subcutaneous injections of rhIGF-1 (100 mu g/kg/12 h), except for one patient who received 50 mu g/kg/12 h for the first five days, followed by 100 mu g/kg/12 h for the following 15 days. Results. During the treatment with rhIGF-1, serum IGF-1 increased by about 100% (P = 0.03), and nitrogen balance became strongly positive (+2.0 g/day, P = 0.015 vs. baseline). This anabolic effect was observed within hours af ter commencing the rhIGF-1 treatment and was largely caused by a 20% decrea se in peritoneal dialysate effluent nitrogen. There was a proportionate red uction in urine nitrogen and serum urea nitrogen. This decrease in nitrogen output was sustained during the entire 20 day of treatment with rhIGF-1. S erum phosphorus decreased significantly during the first several days of rh IGF-1 treatment, whereas serum calcium increased significantly during the r hIGF-1 treatment. Serum potassium and albumin did not change during the rhI GF-1 injections. There was no change in body weight and body composition, a s assessed by anthropometry during the baseline or treatment phases of the study. Some patients exhibited minor possible adverse events that included a reduction in blood pressure and transient tachycardia. Conclusion. Injections of rhIGF-1 induce a strong and sustained anabolic ef fect, as indicated by a positive nitrogen balance in CAPD patients with pro tein-energy malnutrition. rhICF-1 administration may be an effective method for treating malnutrition in maintenance dialysis patients.