The repair of large segmental bone defects in the rabbit with vascularized tissue engineered bone.

Management of segmental bone defects is a considerable challenge for orthopedic surgeons. Tissue engineering is a promising method for repairing bone defects, and vascularization is critical to the performance of a tissue engineered bone. We report herein the construction of a vascularized tissue engineered bone with mesenchymal stem cells (MSCs) and MSC-derived endothelial cells (ECs) co-cultured in porous beta-tricalcium phosphate ceramic (beta-TCP) to repair 1.5-cm ulnar defects in the rabbit. Examination by X-ray and single photon emission computed tomography (SPECT), histologic analysis, and biomechanical tests were used to evaluate repair and the vascularization of the implants. The results showed that by co-seeding MSCs and MSC-derived ECs, the resulting vascularization was able to promote osteogenesis and improve mechanical properties. The rabbits treated with vascularized tissue engineered bone exhibited far more extensive osteogenesis and good vascularization. Therefore, we suggest that the vascularized tissue engineered bone constructed by co-culture of MSCs and MSC-derived ECs in porous beta-TCP may be an effective approach to promote repair of segmental bone defects and have potential for repairing large segmental bone defects in a clinical setting.