A preliminary study on the application of bone marrow stromal cell sheet on the formation of functional tissue-engineered bone in dogs.

Purpose The aim of this study was to construct functional tissue-engineered bone in dogs using cell sheet engineering, a new technique to gain and transfer seed cells. Materials and Methods Demineralized bone matrixes, prepared from homologous bone, were coated with recombinant human bone morphogenetic protein-2. Bone marrow stromal cells (BMSCs) were isolated and subcultured. Osteogenic-induced BMSCs were incubated in a temperature-responsive culture dish to form the BMSC sheet. The complex of demineralized bone matrix, recombinant human bone morphogenetic protein-2, and BMSCs wrapped with BMSC sheets was implanted around the blood vessels of the latissimus dorsi muscle in the experimental side, and the same complex without BMSC sheets was implanted around the blood vessels of the latissimus dorsi muscle on the other side as a control. At 4, 8, 12, and 16 weeks after implantation, the implants were removed for radiographic evaluation, descriptive histologic observation, and histologic quantitative analysis. Results Radiographic analysis showed that the optical density of the tissue-engineered bone on the 2 sides increased with time. However, the optical density of the experimental side was significantly greater than that of the control side at the same points. Sixteen weeks after implantation, mature lamellar bone was formed in the experimental side, with red bone marrow in the bone marrow cavity. In contrast, the control side exhibited significantly less lamellar bone. Histologic quantitative analysis showed that the experimental side exhibited significantly more bone per area compared with the control side. Conclusion BMSC sheet engineering may be useful to construct functional tissue-engineered bone.