Elevated transforming growth factor-beta 1 (TGF-β1) levels in human fracture healing

Introduction: Transforming growth factor-beta 1(TGF-beta 1) is a regulatory protein, involved in bone fracture healing. Circulating TGF-beta 1 levels have been reported to be a predictor of delayed bone healing and non-union, suggesting active relationship between tissue and circulating TGF-beta 1 in fracture healing. The purpose of this study was to analyse TGF-beta 1 local and serum concentrations in fracture healing to further contribute to the understanding of molecular regulation of fracture healing. Patients and methods: Serum samples of 113 patients with long bone fractures were collected over a period of 6 months following a standardised time schedule. TGF-beta 1 serum concentrations were measured using ELISA. Patients were assigned to 2 groups: Group 1 contained 103 patients with physiological healing. Group 2 contained 10 patients with impaired healing. Patients in both groups were matched. One patient of the group 2 had to be excluded because of missing match partner. In addition, fracture haematoma from 11 patients of group 1 was obtained to analyse local TGF-beta 1 concentrations. 33 volunteers donated serum which served as control. Results: TGF-beta 1 serum concentrations increased during the early healing period and were significantly higher in patients with physiological healing compared to controls (P = 0.04). Thereafter, it decreased continuously between weeks 2 and 8 and fell again after week 8. TGF-beta 1 serum concentrations in patients with physiological healing were significantly higher at week 24 compared to controls (P = 0.05). In non-unions, serum concentrations differed significantly from those of controls at week 6 (P = 0.01). No significant difference in between patients with physiological and impaired fracture healing was observed. Fracture haematoma contained significantly higher TGF-beta 1 concentrations than peripheral serum of the patients (P = 0.017). Conclusion: Elevated levels of TGF-beta 1 in haematoma and in serum after bone fracture especially during the entire healing process indicate its importance for fracture healing. (C) 2011 Elsevier Ltd. All rights reserved.