Asian Science Seminar ASS-5
Mechanism of new bone formation by using immature stem cell KUSA/A1 for bone tissue engineering in vivo study
Sathi Gulsan Ara1, 2, Andrea Paola Rodriguez2, 3, Hidetsugu Tsujigiwa2, Hitoshi Nagatsuka2 and
2Department of Oral Pathology and Medicine.
3Department of Oral Pathology.
The basic principle of bone tissue engineering is to seed stem cells in porous scaffold
. Stem cells can proliferate and differentiate into various types of mature cells. On the contrary, mature cells have low proliferation potential thereby not being able to obtain sufficient amount of cells to promote tissue repair. In previous study, we established an appropriate medium to maintain KUSA/A1 cells in their immature stage. These immature cells placed in a diffusion chamber and implanted intra-peritoneally, differentiated into osteoblast-like cells and produced bone-like tissue. In order to induce new bone formation, immature KUSA/A1 cells were seeded into atelocollagen honeycomb carrier. We evaluated the behavior of immature KUSA/A1 cells alone or with honeycomb carrier implanted in subcutaneous tissues of SCID mice. Transplants were subjected to radiographic, histological and immunohistochemical (CD34, Osteopontin, PCNA and BMP-2) examinations after 1, 2 and 4 weeks of implantation. KUSA/A1 cells alone showed few, small islands of new bone formation surrounded by scanty cells. On the other hand, KUSA/A1 with atelocollagen revealed abundant new bone formation as well as cellular proliferation. To clarify the cells implicated in new bone formation, same implantation was done in GFP (green fluorescent protein) mice. The results showed evidence that GFP positive host cells and GFP negative immature KUSA/A1 cells were both responsible for this new bone formation. From this study we concluded that there is a possibility of new bone formation induced by immature KUSA/A1 and host stem cell within atelocollagen honeycomb carrier in vivo.