Bone histomorphometric changes after liver transplantation for chronic cholestatic liver disease

Introduction: Patients with advanced liver disease, especially chronic cholestasis, often have osteopenia, which worsens early after orthotopic liver transplantation (OLT) before starting to recover. The changes in bone metabolism leading to this rapid loss of bone after OLT, and to its recovery, are poorly defined. Materials and Methods: In thirty-three patients with advanced chronic cholestatic liver disease, tetracycline-labeled bone biopsy specimens were analyzed prospectively at time of OLT and at 4 months after OLT, as part of a randomized trial to study the efficacy of calcitonin on post-transplant bone loss. Hierarchical cluster analysis of histomorphometric parameters was performed in an attempt to establish the functional grouping of individual histomorphometric parameters before and after OLT. Results and Conclusions: Results showed that from the time of OLT to 4 months after OLT, bone mineral density of the lumbar spine and histomorphometric parameters of bone volume decreased, consistent with early post-transplant bone loss. Histomorphometric resorption parameters were increased before OLT, with no change after OLT. Histomorphometric formation parameters increased from low values before OLT to normal values at 4 months after OLT, with the exception of mean wall thickness values, which further decreased after OLT, suggesting an additional insult to bone formation during the study period. Histomorphometric changes after OLT were similar in female and male patients, pre- and postmenopausal women, and in patients treated and not treated with calcitonin. Hierarchical cluster analysis suggested that before OLT, bone resorption was functioning independently of bone formation, but that by 4 months after OLT, their coupled relationship had improved. Therefore, despite post-transplant bone loss, by 4 months after OLT, bone metabolism had improved, with increased bone formation and more coupled bone balance, as suggested by hierarchical cluster analysis.