Mechanism of new bone formation by usinf inmature stem cells KUSA/A1 for bone tissue engineering in vivo study

GULSAN ARA SATHI; ANDREA P. RODRIGUEZ; HIDETSUGU TSUJIGIWA; HITOSHI NAGATSUKA; NAGAI NORIYUKI

Kyoto

Congreso; 15th Annual Meeting of The Society of Hard Tissue Regenerative Biology.; 2006

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 KASA/A1 cells in their immature stage. These immature cells placed in a diffusion chamber and implanted intraperitoneally, 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 tissue of SCID mice. Transplants were subjected to radiographic, histological and inmunohistochemical (CD34, Osteopontin, PCNA, and BMP2) examinations after 1, 2 and 4 weeks of implantation. 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 mice. The result 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.