Premium
Large Osteoclasts in Pediatric Osteogenesis Imperfecta Patients Receiving Intravenous Pamidronate
Author(s) -
Cheung Moira S,
Glorieux Francis H,
Rauch Frank
Publication year - 2009
Publication title -
journal of bone and mineral research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.882
H-Index - 241
eISSN - 1523-4681
pISSN - 0884-0431
DOI - 10.1359/jbmr.081225
Subject(s) - osteogenesis imperfecta , medicine , osteochondrodysplasia , surgery , pathology
Intravenous pamidronate is widely used to treat children with moderate to severe osteogenesis imperfecta (OI). Changes in the appearance of osteoclasts have previously been noted in children receiving pamidronate and have been interpreted as signs of toxicity. In this study, we analyzed osteoclast parameters in paired iliac bone specimens before and after 2–4 yr of cyclical intravenous pamidronate therapy in 44 pediatric OI patients (age range: 1.4–17.5 yr; 21 girls). During pamidronate treatment, average osteoclast diameter and the mean number of nuclei present per osteoclast increased by 18% ( p = 0.02) and 43% ( p < 0.001), respectively. The number of samples containing large osteoclasts (LOcs, diameter > 50 μm) increased from 6 (14%) before treatment to 23 (52%) after pamidronate therapy ( p < 0.001 by χ 2 test). Post‐treatment samples containing LOcs had a greater core width ( p = 0.04) and a higher cancellous bone volume per tissue volume ( p < 0.001), because cancellous bone volume had increased more during pamidronate treatment ( p < 0.001). Osteoclast number and surface were higher in samples with LOcs, but there was no difference in cancellous bone formation parameters. The presence of LOcs was independent of OI type, type of collagen type I mutation, lumbar spine BMD, and other clinical or biochemical measures. In conclusion, this study did not show any indication that LOcs during pamidronate treatment are indicative of toxicity. It seems more likely that the observed abnormalities in osteoclast morphology are part of the mechanism of action of this drug.