Analysis of Osteogenic Differentiation of Adipose Tissue-derived Stem Cells

Objectives: Human mesenchymal stem cells from various tissues have attracted particular interest because of their multipotentiality for differentiation and possible application for cell therapy. In the field of periodontal regeneration, not much has been reported on their possibility and availability. Recent studies revealed that adipose tissues contain mesenchymal stem cells. Here we show that adipose tissue-derived mesenchymal stem cells (ADSC) have potential to differentiate into not only adipocytes but also osteoblast-like cells in vitro and may be used for periodontal regenerative therapy.

Methods: Human ADSC were isolated from several donors at Osaka University Medical Hospital Translational Research Center. The Phenotype of ADSC was determined by FACS analysis. The proliferative response was measured by population doublings and the chromosomal analysis was performed by G-Band and SKY methods. The alkaline phosphatase (ALPase) activities, the calcified nodule formation and the gene expression profile of ADSC cultured in mineralization-inducing medium were analyzed by p-nitrophenylphosphate as substrate, alizarin red staining and microarray, respectively.

Results: FACS analysis revealed that ADSC was CD34-, CD45-, CD73+, CD44+, CD105+, CD166+, SSEA4+. ADSC demonstrated a high proliferation rate until 8-passages and never showed abnormal chromosome until 14-passages at which ADSC did not proliferate at all. Cultured in mineralization-inducing medium for 28-days, they increased the ALPase activity and formed calcified nodules. Gene expression profile analysis revealed that mineralization related genes (ex. ALPase, RUNX-2) and periodontal ligament specific gene (PLAP-1/ asporin) were confirmed to be up-regulated.

Conclusion: In this study, we indicated that ADSC could be stably maintained in vitro and be induced to differentiate into osteoblast-like cells. These results suggest that ADSC may be used for cell therapy for periodontal regeneration.