Histomorphometric analysis of bone biopsies from the iliac crest of adults with cystic fibrosis.

This study reports the results of quantitative analysis of iliac bone histology in adults with cystic fibrosis (CF) and low bone mineral density (BMD). Twenty patients with CF had bone biopsies taken after double tetracycline labeling. Histomorphometric measurements were made by image analysis, and data were compared with those of healthy control subjects. Cancellous bone area was lower in the patients with CF (p = 0.003), and there was a trend towards a decrease in cancellous bone connectivity. Bone formation rate at tissue level was significantly lower in patients with CF (p = 0.0002). Wall width, representing the amount of bone formed within individual remodeling units, was decreased (p < 0.0001), as was mineralizing perimeter and mineral apposition rate. Analysis of resorption cavities revealed lower cavity area, reconstructed surface lengths, and cavity depths (p < 0.003) in patients with CF, whereas eroded surface area was higher (p = 0.0004). Our results demonstrate low cancellous bone volume in adult patients with CF with low BMD, the main cause of which appears to be low bone formation at tissue and cellular level. Osteomalacia was diagnosed in one patient. This condition should be excluded as a cause of low bone mineral density in patients with CF and vitamin D insufficiency corrected.

Effects of a single infusion of pamidronate prior to liver transplantation: a bone histomorphometric study.

Osteoporosis is a common and serious complication of solid organ transplantation. Effective therapeutic regimens have not been established but evidence that increased bone turnover is responsible for bone loss early after transplantation provides a rationale for the use of anti-resorptive agents in the peri-operative period. We have examined the effects of a single pre-operative infusion of pamidronate, 60 mg, on bone remodelling and turnover in a prospective study of 12 patients, four male and eight female aged 19-61 years, with chronic liver disease, who formed a subgroup of a larger randomised controlled single-blind study. Iliac-crest biopsies were obtained before and 3 months after liver transplantation and histomorphometry performed using image analysis. In untreated patients ( n=5) a significant increase in bone formation rate at tissue level was demonstrated at 3 months in comparison to pre-operative values (0.035+/-0.013 vs. 0.161+/-0.12 microm(2)/microm/day; mean +/- SD, P=0.003). In patients treated with pamidronate ( n=7) no significant increase in bone formation rate was demonstrated at 3 months, although there was a trend towards an increase in indices of bone turnover. In this group there was also a significant reduction in erosion cavity length (210.4+/-63.8 vs. 179.8+/-67.5 microm; P=0.03) and non-significant reductions in other indices of erosion cavity size. These results indicate that pre-operative administration of pamidronate in patients with chronic liver disease prevents, at least in part, the increase in bone turnover which occurs in untreated patients after transplantation.