In a prospective longitudinal study, we investigated the renal function (RF
) of 23 children before and after orthotopic liver transplantation (OLT), T
he aim was to assess both the outcome of pretransplant hyperfiltration and
the clinical nephrotoxic effects of cyclosporin A (CsA); children with decr
eased RF prior to OLT were therefore excluded. The RF study of the 13 remai
ning patients included glomerular filtration rate (GFR) and effective renal
plasma Row (RPF) measured by inulin (Cin: mL/min/1.73 m(2)) and para-amino
hippurate (Cpah: mL/min/1.73 m(2)) clearances, respectively. Hyperfiltrati
on poor to OLT was observed in six children, i.e. Cin > 170 [range 172-230]
and Cpah > 800 [808-1133]. A significant decrease in RF was noted as soon
as 6 months after OLT: Cin (mean +/- SD)=107 +/- 23 vs. 158 +/- 46 (p <0.00
3); Cpah=583 +/- 119 vs. 791 +/- 243 (p <0.004). This was due to loss of hy
perfiltration in the six children, as there was no significant difference i
n RF before and 6 months after OLT in the other seven children. With a 36-m
onth follow-up, there was no correlation between CsA trough blood level and
RF. In conclusion, following OLT, RF underwent early changes owing to loss
of prior hyperfiltration in children without impaired RF before OLT, In ad
dition, no evidence of CsA nephrotoxicity was found and RF remained stable
during follow-up.