Short-term administration of the bisphosphonate ibandronate increases bonevolume and prevents hyperparathyroid bone changes in mild experimental renal failure

Background: Bisphosphonates (BP) are potent antiresorptive agents that have been used successfully in several bone diseases associated with hyperresor ption. Hyperresorption, hypercalcemia, and osteoporosis are frequent findin gs in patients with renal failure or after renal transplantation The presen t study was carried out to determine the effects of a new BP, ibandronate, on bone in a state of normal vs. moderately impaired renal function. Materi al and methods: Forty 90-day-old female rats were either 2/3 nephrectomized (Nx, n = 20) or sham-operated (Sham, n = 20). Half of the Nx and Sham rats received either ibandronate (1.25 mu g/rat s.c.) or vehicle once weekly fo r three weeks. Before euthanasia, blood drawings were performed and 24-hr u rine was collected. Femurs were analyzed by bone histomorphometry. Results: Serum creatinine, parathyroid hormone, and osteocalcin levels were equally higher in Nx rats given ibandronate or vehicle than in Sham rats. There wa s no difference in serum calcium, phosphorus, alkaline phosphatase, and uri nary creatinine among the groups. Ibandronate-treated rats had lower urinar y calcium and deoxypyridinoline crosslink levels than their Sham counterpar ts. Ibandronate-treated rats had higher bone volume than vehicle-treated an imals. Ibandronate prevented the increase in erosion depth and bone turnove r in Nx rats. Conclusions: BPs such as ibandronate represent potentially us eful tools in the treatment of cer tain facets of renal bone disease. Indic ations for BP therapy may include treatment of osteoporosis, hypercalcemia, and/or extraosseous calcifications. Optimal dose and frequency of BP admin istration need to be determined in these patients.