Isolation and characterization of human periodontal ligament (PDL) stem cells (PDLSCs) from the inflamed PDL tissue: in vitro and in vivo evaluations

Objectives: Mesenchymal stem cells (MSC) could be isolated from healthy periodontal ligaments (PDL). The aims of this study were to isolate and characterize human PDL stem cells (hPDLSCs) from inflamed PDL tissue, and to evaluate their regenerative potential. Materials and Methods: Inflamed hPDLSCs (ihPDLSCs) were isolated from the inflamed PDL tissue obtained from intra-bony defects during flap surgery, and characterized by immunohistochemical staining, colony-forming unit assay, fluorescence-activated cell sorting, and mRNA expression in comparison with healthy hPDLSCs obtained from extracted teeth for orthodontic purpose. The proliferative potential and migratory potential was evaluated, and compared with healthy hPDLSCs. Regenerative potential was assessed by an in vivo ectopic transplantation model. Results: ihPDLSCs were successfully isolated and characterized as MSCs. Both ihPDLSCs and hPDLSCs were successfully differentiated under osteogenic/cementogenic and adipogenic microenvironment. The proliferative potential did not differ between healthy hPDLSCs and ihPDLSCs, while the migratory capacity was significantly increased in ihPDLSCs (p < 0.05). Both groups exhibited new cementum-like tissue and related PDL fibre regeneration in an in vivo transplantation model. Conclusion: ihPDLSCs could be successfully isolated from inflamed PDL tissue, and they retained the regenerative potential for cementum and related PDL tissues.