Aluminum metabolism and bone histology after kidney transplantation: a one-year follow-up study

Abstract

Parathyroid activity, bone aluminum (Al) metabolism, bone histology, and clinical bone disease were studied in 55 successfully grafted kidney recipients at transplantation (Tx) and after 1 yr of immunosuppression with a low dose corticosteroid and a high dose cyclosporin-A regimen. Symptoms of Al-related bone disease disappeared after Tx. Serum Al and stainable bone Al decreased. The rate of Al removal from the bone surfaces was independent of graft function (creatinine range, 62-415 mumol/L) and bone turnover. Osteoblast activity and bone formation rate increased, while mineralization lag time normalized. Indices of bone resorption remained elevated, indicating persisting hyperparathyroidism. Eighteen percent of the recipients had posttransplant hypercalcemia, most likely caused by incomplete involution of hyperplastic parathyroid glands, while 53% had normocalcemic hyperparathyroidism related to impaired graft function. Cortical thickness decreased, while cancellous bone volume remained stable after Tx; both indices correlated significantly at follow-up with their respective values at Tx. None of 46 radiologically examined recipients had aseptic bone necrosis 1 yr after Tx.