Dinamika koštanog metabolizma nakon transplantacije jetre

Abstract

Deterioration of bone metabolism is a major complication of end-stage liver disease. Chronic liver disease and its associated conditions, including hypogonadism, disturbed vitamin D and bile metabolism, malnourishment, alcohol ingestion, and poor physical activity all lead to decrease in bone mineral density (BMD). In addition, loss of bone mass in the early post-transplant period is known to be rapid and has been ascribed to the effects of corticosteroids, immunosuppressive agents and immobilization in the early postoperative period. Bone mass deficit leads to an increased risk of fractures in transplanted patients, with concomittant increased morbidity and mortality in those patients. The primary objective of this study was to monitor bone metabolism, ie. the dynamics of bone resorption and formation, osteoprotegerin, and vitamin D status in the liver transplant patients over the course of the first year following transplantation. The dynamics of bone metabolism was investigated in the study comprised 88 patients and included measurement of biochemical parameters of bone turnover, 25- hydroxy vitamin D and osteoprotegerin (decoy ligand for osteoclast function) at transplantation, afer 14 days, 3, 6 and 12 months. Densitometry was performed at the left hip and lumbar spine in 22 patient after 6 and 12 months. Results of biochemical measurements indicated increased bone resorption during the entire follow-up period, decreased bone formation as assessed by osteocalcin which normalized, 25-OH D deficiency, and initially increased osteoprotegerin which also normalized in this period. Other bone formation markers P1CP and bone alkaline phosphatase were mostly within normal range. Crosslaps decreased after 14 days and thereafter (p=0.005), osteocalcin increased (p<0.02) and osteoprotegerin decreased (p<0.003) after initial measurements; 25-OH D deficiency further decreased after 3 months (p<0.02); P1CP decreased after 3 and 12 months (p<0.02); bone alkaline phosphatase increased after 14 days and 6 months (p<0.03). Bone mass in most patients was either normal or osteopenic, with improvement at the left hip after 12 months (p<0.01), but no change at the lumbar spine. Metabolic bone disorder in the first post-transplant year was characterised by decreased bone formation which improves almost immediately after liver transplantation, and continuosly increased bone resorption. Variations in osteoprotegerin levels corresponded to osteoblast and osteoclast cell activities. Bone mass in liver transplant recipients was normal or osteopenic, but improved only for the hip site