Comparaison des effets de la ciclosporine-A et du tacrolimus sur le métabolisme osseux des patients transplantés rénaux : une étude transversale chez 28 patients

Abstract

Background. – Controversy exists about the effects of calcineurin inhibitors on bone metabolism. We decided to compare the effects of CyA vs FK506 on bone metabolism of kidney recipients. Patients and methods. – From 94 patients grafted at the University Hospital of Nice between 1996 and 1999 treated either by CyA ( N =49) or by FK506 ( N =45), we selected 14 pairs (18 M, 10F), matched for gender, BMI, time lapsed since transplantation and gonadal status in females. Patients with >1 transplantation or >1 rejection episode were excluded. Cumulative dose of steroids was recorded. Bone mineral density (BMD) was mesured at heel and forearm, as well as serum concentration of calcium, phosphate, parathyroid hormone (PTH), vitamin D metabolites, C-telopeptide (CTX), creatinine, estradiol as well as Bone Alkaline Phosphatase (BAP) activity. Results. – Despite the matching, time on hemodialysis was longer in FK506 group. Cumulative dose of steroids was similar between groups. There was no difference between groups in BMD and biochemical parameters except for estradiol serum levels which were dramatically lower in FK506 than in CsA ( P =0,02) and for a trend (p=0,08) for BAP and CTX to be higher in FK506 than in CsA. Conclusions. – BMD is not lower in FK506– than in CsA–treated patients although exposure to hyperparathyroidism was longer and estradiol levels were lower in the FK506 than in the CsA group. These data suggest that FK506 may have a favorable bone effect to compensate for these deleterious factors. This hypothesis remains to be tested in longitudinal studies.