ELEVATED IGF-II AND TGF-BETA CONCENTRATIONS IN HUMAN CALVARIAL BONE -POTENTIAL MECHANISM FOR INCREASED GRAFT-SURVIVAL AND RESISTANCE TO OSTEOPOROSIS

Calvarial bone grafts may have greater survival as donor tissue than b one from other sites. Furthermore, calvarial bone is resistant to oste oporosis. Because bone contains growth factors that may play an import ant role in the regulation of bone repair, we proposed that bone from calvaria may be enriched in one or more growth factors. To test this h ypothesis, samples of bone from 10 men 64 years of age or older that w ere obtained at autopsy from three skeletal sites (calvaria, iliac cre st, and vertebral body) were cleaned, extracted by demineralization, a nd assayed for growth factors insulin-like growth factor I, insulin-li ke growth factor II, and transforming growth factor-beta. Insulin-like growth factor II and transforming growth factor-beta concentrations w ere significantly higher in calvaria than in iliac crest or vertebral body. We conclude that the increased concentrations of growth factors in calvarial bone may lead to a greater capacity for bone repair and g raft retention.