Dialysis modality comparison of insulin-like growth factor binding protein-3 removal in children: could this have a potential growth benefit?

Centers have reported superior growth in children on peritoneal dialysis (PD) as compared to hemodialysis (HD). Many factors may influence this outcome including diet, adequacy of dialysis, and control of metabolic acidosis. The role of insulin-like growth factor-1 (IGF-1) and its bioactivity in patients with end-stage renal disease (ESRD) have been recently examined. Insulin-like growth factor binding protein-3 (IGFBP-3) has been shown to be elevated in ESRD, possibly resulting in inhibition of the bioactivity of IGF-1. Potentially, the removal of IGFBP-3 may improve the bioactivity of IGF-1, with resulting improvement in growth. The molecular weight of IGFBP-3 (30.5 kDa) is in the range of other proteins cleared by PD (e.g., albumin-69 kDa). Therefore, we have analyzed 10 samples of IGFBP-3 in the dialysis effluent of 9 children on peritoneal dialysis, and have found that the mean level +/- SEM was 0.21 +/- 0.03 mg/L, while the 3 analyses of children on standard HD was 0.02 +/- 0.01 mg/L. In addition, the effluent of 2 children on a high-efficiency dialyzer had an IGFBP-3 level of 0.45 +/- 0.25 mg/L. Even though quite preliminary, these data may suggest another reason for improved growth in children on PD and a potential advantage to high-efficiency HD. Further analysis in a larger population of ESRD patients will be needed in order to confirm these preliminary findings.