Renal functional adaptation of the adult kidney following transplantation to the child

Abstract

Nineteen child renal transplant recipients, aged 1.3 to 19.2 years at transplantation, and their adult living-related kidney donors, 27 to 60 years of age at nephrectomy, were investigated simultaneously with regard to renal function. At a median time of three months after transplantation clearances of inulin (GFR) and para-aminohippuric acid (ERPF) were measured, and serum urea and creatinine concentrations were determined. The absolute values for GFR (72 ± 13 ml/min) and ERPF (369 ± 76 ml/min) in the donors were significantly higher than those of the recipients (37 ± 22 and 196 ± 72 ml/min, respectively). The absolute values of GFR and ERPF were significantly correlated with the body surface areas of the recipients. Thus, in relation to body surface area, the GFR, 68 ± 11 ml/min/1.73 m2, and ERPF, 348 ± 65 ml/min/1.73 m2, of the donors did not differ from those of the recipients, 68 ± 20 and 375 ± 90 ml/min/1.73 m2, respectively. Because of the greater body mass, the serum creatinine concentrations of the donors were significantly higher than those of the recipients, whereas the serum urea concentrations were significantly higher in the recipients. The results suggest that transplantation of an adult kidney to a child results in a functional adaptation to the smaller body size of the recipient, and that this adaptation occurs within three months after transplantation.