Clinical outcomes of recipients with aplastic bone disease after renal transplantation

We expect that if chronic renal failure (CRF) is improved after renal transplantation (RTx), dialysis osteopathy bone lesions would also recover to normal. Nevertheless, it is controversial whether bone lesions really improve after RTx. In this study, we evaluated whether pathological dialysis osteopathy improved after RTx.

The 84 patients who had undergone living related RTx had also undergone a bone biopsy (Bx) since January 2004, including 13 (16.0%) with a diagnosis of aplastic osteopathy. They included 7 men and 6 women. The average hemodialysis (HD) period was 40.3 months. The immunosuppression was tacrolimus (FK); mycophenalate mofetil (MMF) and steroid. We examined Ca, P, intact-PTH (i-PTH), metabolic bone markers, and bone density (DXA) before and 1 year after RTx. In addition, a Bx was performed after having osteal labeling twice before Bx. In addition 2 cases (15.3%) also underwent a Bx after RTx.

All cases survive with well functioning renal grafts. The mean levels of Ca and P before RTx were 8.7 mg/mL and 6.6 mg/dL, respectively. The mean i-PTH level was 137.8 pg/mL before RTx and of alkaline phosphatase (ALP) was 202.1 U/L before RTx. The total density and % age match of DXA before RTx averaged 398.7 mg/ccm and 96.7%, respectively. The mean bone volume fraction (BV/TV: Bone Volume/Tissue Volume) before RTx was 17.2%. The mean osteoid volume (OV/TV) before RTx was 2.7%. The mean fibrosis volume (Fb.V/TV) before RTx was 0%. The mean bone formation rate (BFR/BV) before RTx was 2.1 %/y. Two cases were also pathologically diagnosed as renal osteodystrophy at 1 year after RTx: 1 case was mixed type, and another was osteomalacia, which was accompanied by a lumbar compression fracture (Fx) during the clinical course.

Bone metabolism in patients with aplastic ROD histologically improved at 1 year after RTx, presumably due to good renal transplant function. However, it is unknown whether both hypophosphatemia and decrease of FGF-23 improved bone However, patients with aplastic ROD were not completely normalized histologically at 1 year after RTx.