Abstract 28

It has been described that patients with chronic renal insufficiency (CRI) after RTx have a low IGF-1/IGFBP-3 MR which increases under rhGH, suggesting that this MR reflects IGF-1 bioavailability and that the increment explains the response to treatment. The aim of this study was to correlate IGF-1/IGFBP-3 MR and growth velocity (GV) after RTx. GV was calculated as SDS for bone age (BA) during the 0.5 to 1 year (y) period previous to blood sampling. Clinical material: Group (Gr)1, before rhGH, 7 prepubertal (PP) and 6 pubertal (P), total 13 patients, with post-RTx time (X±SD) 1.59±0.67 y chronological age (CA 12.9±2.6 y and BA 9.39±2.93 y; Gr2, during rhGH 2PP and 8 P (total 10) patients, with post-RTx time 2.84±1.87 y, CA 13.9±3.77 y, BA 9.20±3.30 y, and rhGH treatment duration range 1 to 3.5 y. Results: in Gr1, GV SDS was - 2.5±3.55 and IGF-1/IGFBP-3 MR 0.20±0.12; in Gr2, rhGH did not change CA-BA difference (4.67±2.58 and 4.5±2.27, before and during rhGH respectively), GV SDS was 0.87±1.98 and IGF-1/IGFBP-3 MR 0.30±0.21. GV SDS, but not IGF-1/IGFBP-3 MR, was significantly higher in Gr2 (p=0.007). No significant correlation between GV SDS and IGF-1/IGFBP-3 MR was found neither in Gr1 nor in Gr2. It is concluded that the IGF-1/IGFBP-3 MR is not an adequate parameter to evaluate IGF-1 bioavailability not response to rhGH treatment. Changes in serum IGF-2 and/or in other IGFBPs, which are not taken into account in this MR, could play a significant role in the pathophysiology of growth in CRI.