Safety study: is there a pathologic IGF-1, PDGF and TGF-β cytokine expression caused by adjunct BMP-7 in tibial and femoral non-union therapy?

Christian Fischer; Christian Reiner; Gerhard Schmidmaier; Julian Doll; Christopher Child; Paul Alfred Grützner; Bahram Biglari; Sonja Boxriker; Arash Moghaddam

doi:10.2147/TCRM.S160064

Safety study: is there a pathologic IGF-1, PDGF and TGF-β cytokine expression caused by adjunct BMP-7 in tibial and femoral non-union therapy?

Ther Clin Risk Manag. 2018 Apr 16:14:691-697. doi: 10.2147/TCRM.S160064. eCollection 2018.

Authors

Christian Fischer¹, Christian Reiner², Gerhard Schmidmaier¹, Julian Doll¹, Christopher Child³, Paul Alfred Grützner⁴, Bahram Biglari⁴, Sonja Boxriker⁵, Arash Moghaddam⁵

Affiliations

¹ Center for Orthopedics, Trauma Surgery and Spinal Cord Injury, HTRG - Heidelberg Trauma Research Group, Heidelberg University Hospital, Heidelberg, Germany.
² Department of Trauma and Orthopedic Surgery, Paracelsus Medical University, Nuremberg Hospital South, Nuremberg, Germany.
³ Department of Trauma Surgery, University Hospital Zurich, Zurich, Switzerland.
⁴ Trauma and Orthopedics, BG Trauma Center Ludwigshafen, Ludwigshafen, Germany.
⁵ Center of Orthopedics, Trauma Surgery and Sport Medicine, ATORG Aschaffenburg-Alzenau, Aschaffenburg, Germany.

Abstract

Background: In this prospective safety study, we investigated if the characteristic cytokine expression during bone regeneration is manipulated by the local application of bone morphogenetic protein-7 (BMP-7) in non-union surgery. Therefore, the levels of insulin like growth factor 1 (IGF-1), platelet-derived growth factor AB (PDGF-AB) and transforming growth factor beta (TGF-β) were compared between patients with the gold standard use of autologous bone graft (ABG) and those with additional application of BMP-7 as part of the diamond concept.

Patients and methods: Between 2009 and 2014, of the 153 patients with tibial and femoral non-unions, a matched pair analysis was performed to compare the serological cytokine expressions. Blood samples were collected preoperatively, 1, 2 and 6 weeks as well as 3 and 6 months after non-union surgery. Matching criteria were smoking status, fracture location, gender, age and body mass index (BMI). Patients in G1 (n=10) were treated with ABG and local BMP-7 while their matching partners in G2 (n=10) received ABG only. The routine clinical and radiologic follow-up was 1 year.

Results: Although the IGF-1 quantification in G2 showed higher pre- and postoperative values compared to G1 (p<0.05), the courses of both groups were similar. Likewise, PDGF-AB and TGF-β expressions appeared similar in G1 and G2 with peaks in both groups at 2 weeks follow-up. Osseous consolidation was assessed in all operated non-unions. The adjunct application of BMP-7 did not cause any pathologic cytokine expression.

Conclusion: Similar expressions of the serum cytokines IGF-1, PDGF-AB and TGF-β were demonstrated in non-union patients treated with ABG and additional application of BMP-7 according to the diamond concept. Our findings indicate that the local application of BMP-7, which imitates the physiologic secretion of growth factors during bone regeneration, is safe and without the risk of abnormal systemic cytokine expression. Studies with higher patient numbers will have to validate these assumptions.

Keywords: bone morphogenetic protein; cytokine; non-union; safety.