Growth factors in distraction osteogenesis - Immuno-histological pattern of TGF-beta 1 and IGF-I in human callus induced by distraction osteogenesis

Although growth factors have been demonstrated during bone healing, their p resence has not yet been confirmed in callus distraction. Therefore, in 3 p atients we searched for cytokines during callus distraction. Bone biopsies were immuno-histochemically stained for TGF-beta 1, IGF-I, TGF-beta type II receptor, IGF receptor, and proliferating cell nuclear antigen (PCNA). His tologically we found immature woven bone in the middle of the callus zone a nd increasing calcification and lamellar bone in the re-modelling zone. Ost eoblasts and fibroblast-like cells in the middle zone, and osteoblasts in a ll zones stained for TGF-beta and its receptor. The number of positive stai ning cells related to proliferous activity as assessed both by PCNA, and by bone density in radiographs. IGF-I could be detected every where. In concl usion, growth factors are present in bone formation and in areas of re-mode lling during callotasis. Their relation to proliferous activity and radiogr aphic density supports their involvement in osteogenesis.