Glucocorticoid-induced osteopenia in adolescent heart transplant recipients

Abstract

Background Glucocorticoid-induced cushingoid symptoms, including osteopenia and osteoporosis are well-documented in adult heart transplant recipients (HTR). Bone mineral density (BMD) of the axial skeleton is diminished by 10% to 20% within 60 days after transplantation (Tx) and most adult HTR fulfill World Health Organization criteria for osteoporosis (BMD > 2.5 SD below norm). At present, we do not know whether glucocorticoids have similar deleterious effects in adolescent HTR. Methods To determine the consequences of glucocorticoid immunosuppression on regional bone mineral density (BMD) and biochemical markers of bone metabolism in adolescent HTR, we studied 19 patients (aged 16 ± 3) at 19 months (group mean) after Tx. We measured BMD (hydroxyapatite g/cm 2) of the total body, lumbar spine, and pelvis using dual-energy X-ray absorptiometry (Lunar). Serum levels of bone-specific alkaline phosphatase and pyridinoline cross-links were determined by enzyme immunoassay in serum kits. Results The BMD of the lumbar spine (−12%), femur neck (−13%), femur trochanter (−12%), and ward’s triangle (−16%) were significantly ( p < 0.05) lower in adolescent HTR than age- and gender-matched norms. Serum levels of alkaline phosphatase (29 ± 6 vs 22 ± 3 U/liter) and pyridinoline cross-links (5.3 ± 1.1 vs 3.8 ± 0.7 mmol/liter) were significantly ( p < 0.05) elevated in adolescent HTR, compared with age- and gender-matched controls studied in our laboratory. Conclusions Our cross-sectional results demonstrate that BMD of the axial skeleton in adolescent HTR is significantly lower (−10% to 20%) than age-matched norms and that serum biochemical markers of bone metabolism are significantly elevated, suggesting accelerated bone turnover.