In Vitro And In Vivo Osteogenesis Of Dermis-derived BMPR-IB+ Cells

The treatment of large bone defects is still a great clinical challenge. Shortage of donor is the dilemma of traditional method by allogeneic bone graft. Thus bone tissue engineering constructed by allogeneic cells has been a promising solution.Objective:Cell surface marker BMPR-IB was adopted to isolate cell subpopulation with osteogenic potential from skin. Construct tissue engineering bone with coral and isolated BMPR-IB+ cells which were used as seed cells to repair bone defects. Evaluate the osteogenic potential of BMPR-IB+ cells in vitro and in vivo.Materials and methods:BMPR-IB+ cells was isolated from foreskin samples. The unsorted dermal fibroblasts were served as control. The proliferation and osteogenic potential of BMPR-IB+ cells were examined in vitro. After seeding onto coral scaffolds, the adhesion, proliferation and osteogenesis of BMPR-IB+ cells were examined. Using BMPR-IB+ cells-coral scaffold complex to repair 4mm diameter calvarial defects of nude mice. Unsorted dermal fibroblasts-coral scaffold complex and coral alone were served as control. New bone tissues were examined by gross view, 3D-CT and histological analysis.Results:The expression rate of BMPR-IB+ cells in dermal cells was about 3.5%, and the cells were mostly localized in dermal reticular layer. The BMPR-IB+ cells could differentiate into osteoblasts in vitro. After seeding onto coral scaffolds, the cells attached to the scaffolds, grew well and maintained osteogenic potential. In the early stage after transplantation to repair calvarial defects, lots of new bone formation was observed by histological analysis. In the late stage after tansplantation for 24 weeks, 3D-CT scanning demonstrated that BMPR-IB+ cells-coral scaffold complex could repair calvarial defects successfully, while little bone formation was observed in unsorted dermal fibroblasts-coral scaffold complex and coral alone groups. Histological analysis demonstrated that the latters were repaired by fibrous connective tissue.Conclusions:There was cell subpopulation that expressed cell surface marker BMPR-IB in skin which could be isolated by magnetic activated cell sorting. The dermis-derived BMPR-IB+ cells had the same proliferative potential with the unsorted dermal fibroblasts, but possessed much higher osteogenic potential in vitro. The constructed BMPR-IB+ cells-coral scaffold complex could repair calvarial defects of nude mice which exhibited that dermis-derived BMPR-IB+ cells had a potential for bone defect regeneration.