Tissue Eng Part A. 2014 Sep 24. [Epub ahead of print]

Mesenchymal stem cells with increased SDF-1 expression enhanced fracture healing.

Ho CY¹, Sanghani A, Hua J, Coathup MJ PhD, Kalia P, Blunn G.

Abstract

Treatments of critical size bone defects pose a challenge in orthopaedics. Stem cell therapy together with cytokines has the potential to improve bone repair as they cause the migration and homing of stem cells to the defect site. However, the engraftment, participation and recruitment of other cells within the regenerating tissue are important. To enhance stem cell involvement, this study investigated over-expression of stem cells with SDF-1 using an adenovirus. We hypothesised that these engineered cells would effectively increase the migration of native cells to the site of fracture, enhancing bone repair. Prior to implantation, we show that SDF-1 secreted by transfected cells increased migration of non transfected cells. In a rat defect bone model, bone marrow mesenchymal stem cells over-expressing SDF-1 showed significantly (p=0.003) more new bone formation within the gap and less bone mineral loss at the area adjacent to the defect site during the early bone healing stage. In conclusion, SDF-1 was shown to play an important role in accelerating fracture repair and contributing to bone repair in rat models, by recruiting more hosts' stem cells to the defect site and encouraging osteogenic differentiation and production of bone.