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Insulinlike growth factor gene expression in human fracture callus

Research paper by J. G. Andrew, J. Hoyland, A. J. Freemont, D. Marsh

Indexed on: 01 Aug '93Published on: 01 Aug '93Published in: Calcified Tissue International



Abstract

The effects of insulinlike growth factors on bone and cartilage-derived cells in culture have been extensively investigated, but there is little information on their rolein vivo in bone, especially in fracture healing. This study investigated insulinlike growth factor (IGF) I and II mRNA expression in normally healing human fractures byin situ hybridization. Endothelial and mesenchymal cells at the granulation tissue stage expressed IGF-II mRNA. At the stage of bone and cartilage formation, osteoblasts and nonhypertrophic chondrocytes expressed mRNA for both IGF-I and II. Some osteoclasts were positive for IGF-II mRNA at the stage of bone remodeling. The greater time span of IGF-II expression relative to IGF-I reflects the predominance of IGF-II in human bone matrix. Taken together with the known effects of IGFs on bone and cartilage cellsin vitro, these findings support a role for IGFs in local cellular regulation in human fracture healing.