In vivo bone formation by human alveolar-bone-derived mesenchymal stem cells obtained during implant osteotomy using biphasic calcium phosphate ceramics or Bio-Oss as carriers.

Abstract

The aim of this study was to evaluate HA coated with different ratios of TCP as a carrier for hABMSCs obtained during implant osteotomy in comparison to slowly-resorbing biomaterial, Bio-Oss, as a negative control, using in vitro and in vivo experiments. Human ABMSCs (hABMSCs) harvested during implant osteotomy were transplanted using HA/TCP or Bio-Oss as carriers in a murine ectopic transplantation model (n = 12). Pore size and cell affinity were evaluated in vitro. The area of newly formed bone was analyzed histometrically, the number of osteocytes was counted, and immunohistochemical staining was conducted against several markers of osteogenesis, including alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX-2), osteocalcin (OCN), and osteopontin (OPN). Osteoclast formation was evaluated by tartrate-resistant acid phosphatase staining. The carrier materials had comparable pore sizes. The cell affinity assay resulted in a high proportion of cell adhesion (>90%) in all experimental groups. Substantial new bone and osteocyte formation was observed on both HA/TCP carriers, whereas it was minimal with Bio-Oss. Positive immunostaining for ALP, RUNX-2, OCN, and OPN was observed with HA/TCP, but only limited expression of osteogenic markers with Bio-Oss. Conversely, there was a minimal osteoclast presence with Bio-Oss, but a significant presence of osteoclasts with both HA/TCP carriers. Both types of scaffolds, BCP and Bio-Oss, showed high stem cell-carrying potential, but the in vivo healing patterns of their complexes with hABMSC could be affected by the microenvironment on the surfaces of the scaffolds.