Isolation and characterization of the human immature osteoblast culture system from the alveolar bones of aged donors for bone regeneration therapy

Background: Establishment of human osteoblast cultures that retain bone-forming capacity is one of the prerequisites for successful bone regeneration therapy. Because osteoblasts harvested from adults exhibit limited growth, the use of immature osteoblasts that can expand ex vivo should greatly facilitate bone regeneration therapy. In this study, we developed immature human osteoblasts isolated from aged alveolar bone (HAOBs). Methods: HAOBs obtained after the collagenase digestion of alveolar bones from elderly donors. Then, we assessed osteogenic ability of HAOB after treatment with recombinant human bone morphogenic protein-2 or transplantation into immunodeficient mice. In addition, we performed global gene expression analysis to identify functional marker for HAOB. Results: HAOBs, which can differentiate into osteoblasts and have a robust bone-forming ability, were successfully extracted from donors who were > 60 years of age. We found that the HAOBs exhibited a higher osteogenic ability compared with those of human mesenchymal stem cells and highly expressed NEBULETTE (NEBL) with osteogenic abilities. Conclusions: HAOBs have properties similar to those of human immature osteoblasts and appear to be a novel material for cell-based bone regeneration therapy. Additionally, the expression level of NEBL may serve as a marker for the osteogenic ability of these cells.