Bone histopathology and densitometry comparison between cyclosporine a monotherapy and prednisolone plus azathioprine dual immunosuppression in renal transplant patients.

BACKGROUND: No study has compared the bone histopathologic findings in renal transplant patients receiving cyclosporine A (CsA) monotherapy with those in patients receiving a non-CsA regimen. The aim of this study was to compare bone densitometry and histomorphometry findings in patients receiving CsA monotherapy versus those receiving azathioprine + prednisolone dual therapy.

METHODS: A bone biopsy and densitometry were performed in 13 patients receiving CsA monotherapy and 12 patients receiving azathioprine + prednisolone, who had been on these regimens since the time of transplantation. Fourteen men and 11 women, age 51+/-12 years, with 140+/-75 months since transplantation, were included.

RESULTS: A low bone mineral density (BMD) was observed in patients on both immunosuppressive schemes-most notably at the distal radius and less significantly at the lumbar spine. No significant differences in BMD were observed between immunosuppressive groups. Histopathologic analysis of the group as a whole revealed mixed uremic bone disease in 42%, adynamic bone in 29%, hyperparathyroid disease in 17%, and normal bone in 12%. Patients showed a slight increase in osteoclast number and function, decreased osteoblast number and function, and retardation of dynamic parameters. No differences in histopathologic diagnosis or histomorphometric findings were observed between the immunosuppressive therapy groups. In addition to the immunosuppressive drugs, male gender and old age negatively affected bone mass.

CONCLUSIONS: Both prednisolone and CsA were associated with slight osteoclast stimulation and osteoblast suppression and marked retardation of mineral apposition and bone formation rates. Both drugs were also associated with reduced BMD at the axial and appendicular skeleton, even though a nonsignificant trend to a better-preserved lumbar spine BMD was observed in the CsA group.