Elucidation of 3D cell growth and its applications for periodontal regeneration therapy

组织工程学为牙周组织的再生提供了一条新的途径。然而，在牙周组织工程中，大多数相关细胞的来源受到可及性差的限制，而容易获得的牙龈成纤维细胞的使用受到阻碍，因为它们对骨形成的抑制作用。为了解决后一个缺点，我们开发了一种新的移植物，由基于纤维连接蛋白（FN）基质的多层细胞片的人牙龈成纤维细胞修饰表达碱性磷酸酶（ALP）。这项研究是为了研究这种移植物（称为FN-ALP移植物）对大鼠模型牙周缺损愈合的影响。种植后，FN-ALP通过膜内骨化修复牙槽骨缺损，形成牙骨质和牙周膜。FN-ALP移植通过软骨内骨化增加了缺损附近下颌骨皮质的新骨形成。移植的成纤维细胞在骨化过程早期位于宿主成骨细胞和软骨细胞前体细胞附近，但在新形成的骨和软骨上和中检测不到。这些结果表明，FN-ALP移植支持牙槽骨缺损内的再生和增加骨形成的缺陷外，通过招募宿主骨/软骨细胞，表明其潜在的牙周组织工程应用。

Tissue engineering offers a promising new approach to regenerating lost periodontal tissues. In periodontal tissue engineering, however, the sourcing of most of the relevant cells is limited by poor accessibility, whereas the use of readily available gingival fibroblasts is hampered because of their inhibitory effects on bone formation. T address the latter drawback, we developed a new graft composed of fibronectin (FN) matrix-based multilayered cell sheets of human gingival fibroblasts modified to express alkaline phosphatase(ALP). This study was undertaken to invest the effects of this graft, called the FN-ALP transplant, on the healing of periodontal defects in a rat model. After implantation, the FN-ALP transplants healed alveolar bone defects by intramembraneous ossification, with formation of cementum and periodontal ligament. FN-ALP transplants increased new bone formation, by endochondral ossification, on the mandibular cortex adjacent to the defect. Grafted fibroblasts were located near host osteoblasts and chondrocyte precursor cells early in the ossification process but were undetectable on and in newly formed bone and cartilage. These results indicate that the FN-ALP transplants support alveolar bone regeneration within the defect and augment bone formation outside the defect through the recruitment of host osteo/chondrogenic cells, suggesting their potential for periodontal tissue engineering applications.