Bone reconstruction by cultured bone graft

Grafting of the patientʹs own bone is ideal from the perspective of osteogenic potential, and also produces the best results clinically. If a tissue engineering approach is used to produce autogenous bone ex vivo with culture techniques, extensive bone defects could be repaired without any damage to the normal tissues. Maniatopoulos et al. reported the formation of calcified bone-like tissue when bone marrow cells were cultured with dexamethasone and beta-glycerophosphate. Combining this cultured bone tissue with synthetic bone material has allowed the production of synthetic bone containing proliferating bone marrow cells with increased osteogenic potential. The in vitro biochemical and morphological study showed that the synthetic bone with a matrix similar to the normal bone and a high level of osteoblastic activity, can be produced by culture in just over 2 weeks. The histological and biochemical analyses of the synthetic bone after subcutaneous implantation in vivo, revealed that bone formation commenced 1 week after implantation and continued for 8 weeks. Expression of alkaline phosphatase and osteocalcin mRNA was confirmed at 1–2 weeks after the implantation of synthetic bone, and was comparable to the expression level in the normal cancellous bone. These findings also demonstrated that this synthetic bone exhibits a high osteogenic potential in vivo. When human bone marrow cells are cultured using the method of Maniatopoulos et al., bone tissue forms in vitro. Cultured synthetic bone, which has been confirmed by animal experiments to possess high osteogenic potential, can also be produced using human bone marrow cells. The method of creating synthetic bone described here allows the grafting of autogenous bone while preserving normal tissue. In addition, culture can be used to increase the number of bone marrow cells, thereby allowing the repair of extensive bony defects.