| Co-Investigator(Kenkyū-buntansha) |
TANAKA Yasuhito Nara Medical University, Dept.of Orthop., Assistant Professor, 医学部, 講師 (30316070)
KAWATE Kenji Nara Medical University, Dept.of Orthop., Assistant Professor, 医学部, 助手 (70275329)
YOSHIKAWA Takafumi Nara Medical University, Dept.of Orthop., Assistant Professor, 医学部, 講師 (90275347)
OHGUSHI Hajime Research Institute for Cell Engineering and Tissue Engineering Research Group, Technology, Head of Group, セルエンジニアリング研究部門・組織・再生工学研究グループ, グループ長 (80213669)
|
|---|
| Budget Amount *help |
¥4,100,000 (Direct Cost: ¥4,100,000)
Fiscal Year 2005: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2004: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 2003: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
|
|---|
| Research Abstract |
1,Early Bone in-growth Ability of Alumina Ceramic Implants Loaded with Tissue-Engineered Bone
To enhance early bonding of an alumina ceramic implant to bone, we evaluated a method of seeding the implant surface with bone marrow mesenchymal cells that differentiated to osteoblasts and bone matrix prior to implantation. The usefulness of the method was evaluated in Japanese white rabbits. In our study, an alumina ceramic test piece loaded with differentiated osteoblasts and bone matrix by a tissue engineering technique was implanted into rabbit bones. Three weeks after the procedure, evaluation of mechanical bonding, X-ray and micro computed tomography (CT) images and histological examination were performed. In the mechanical test, the average failure load was 0.60±0.21 kgf for the non-cell-loaded side and 1.49±0.29 kgf for the cell-loaded side. In X-ray examination, radiographs showed th non-cell-load surfaces showed a radiolucent zone between the implant and bone, but that the cell-load
… More
ed surfaces with direct contact between the implant and bone. In micro CT images, the non-cell-loaded side showed a low-intensity region, indicating connective tissue, but that the cell-loaded side showed a high-intensity region, indicating new bone formation. Furthermore, histological examination of the non-cell-loaded implant surfaces showed no bone infiltration into the implant gap. However, the cell-loaded implant surfaces exhibited new bone infiltration into the implant gap with mechanical bonding. The present findings indicate early bonding between the alumina ceramic implant and bone three weeks after the procedure. Therefore, using these approaches, such as preculturing mesenchymal cells on the surface of the implants prior to implantation increased the debonding strength. The benefits would be applicable not only to alumina ceramic implants, but to all types of bone implants. That is, we may be able to alter the surface of bioinert materials through bioactive substances with osteogenic function.
2,Osteogenic Activity of Human Marrow Cells on Alumina Ceramics
Three ml of fresh marrow cells was aspirated from anterior iliac crest of the osteoarthritic patients and cultured. in a humidified atmosphere of 95% air with 5% CO_2 at 37℃. After six to 11days of the primary culture, adherent cells were released from the substratum and applied on the ceramic surface (1 x 10^5cells/cm^2) as well as culture dish and further cultured in the medium supplemented with 10 mM Na beta-glycerophosphate, 82 μg/ml vitamin C phosphate (L-Ascorbic Acid Phosphate Magnesium salt n-Hydrate) and with or without 100nM dexamethasone (Dex). Alkaline phosphatase activity (ALP) was measured by biochemical assay and mineralization processes by cultured cells were monitored using calcium binding fluorescent dyes. The calcein uptake was also quantified in situ by using an image analyzer. Cultured cells grew well on the alumina ceramics as well as culture dish surface and showed abundant mineralization evidenced by calcein uptake and alizarin red staining in the culture with Dex. ALP activities of the cells cultured on the alumina ceramics and culture dish were less than 0.06 μmole/30min/μg DNA in the absence of Dex but significantly higher of these cells in the presence of Dex and these activities were in the range of 0.15 to 0.4 μmole/30min/μg DNA. Present data showed that alumina ceramic is qualified material for culturing human marrow mesenchymal cells, which finally differentiate into osteoblasts. Importantly, the differentiated osteoblasts can make bone matrix consisting of hydroxyaptatite crystal on the alumina ceramic surface.
3,Preliminary Clinical Result of the Tissue Engineered Artificial Ankle Joint Replacement
An alumina ceramic total ankle prosthesis loaded with cultured cells were used for the replacement of the osteoatthritic ankles in 3 patients. Clinical and radiographic results were investigated 2 years after surgery. Clinical AOFAS (American Orthopaedic Foot Ankle Surgety) scores of the patient were improved significantly. Radiographic findings showed early bohe fixation around the cell seeded areas even 2 months after the operation. Coverage of osteoblast/bone matrix on the ceramic surface vests the ceramics with osteogenic capability, which demonstrate the early bone fixation around the ceramic total ankle joint. All of these results show our method using patient marrow mesenchymal cells and alumina ceramics is the promising approach for the reconstruction arthritic joints. Less
|
