Renal function of children exposed to cyclosporin in utero

Background. The use of cyclosporin (CsA) has improved graft survival in transplant (Tx) patients despite its potential nephrotoxicity. Children born to transplanted women may present with intrauterine growth retardation (IUGR). On the basis of potential reduced nephron mass both in IUGR and in newborn experimental animals exposed to CsA in utero, we investigated the renal function of children >1 year of age born to women under maintenance immunosuppression, including CsA. Methods. Fourteen children born to 12 Tx women (nine kidney, one pancreas-kidney, one heart, one liver) were investigated using inulin clearance (C-in), paraaminohippuric acid clearance (C-PAH), microalbuminuria, and electrolyte reabsorption rate. Results. Gestational age of the 14 infants was 34 +/- 3 weeks and birth weight 2018 +/- 620 g. During pregnancy, CsA trough blood level was 234 +/- 115 mu g/l and plasma creatinine range was 96-136 mu mol/l. Two children were excluded from the study because renal investigation led to a diagnosis of hereditary nephritis (one Alport syndrome, one familial dominant focal segmental glomerulosclerosis) that was retrospectively completed in the mother. Renal function tests were finally performed in 12 children at 2.6 +/- 1.8 years of age: BP 94 +/- 7/55 +/- 5 mmHg, C-in 117 +/- 28 ml/min/1.73 m(2), C-PAH 545 +/- 124 ml/min/1.73 m(2), filtration fraction 0.23 +/- 0.03, microalbuminuria 4.2 +/- 3.5mg/mmol. Electrolyte tubular reabsorption rates and urine concentrating capacity were normal. Conclusion. These results suggest that in children born to transplanted women taking CsA, renal function develops normally despite prolonged exposure in utero.