Enhancement of periodontal tissue regeneration by transplantation of bone marrow mesenchymal stem cells

Background: The use of suitable cells transplanted into periodontal osseous defects appears to be a powerful strategy to promote periodontal tissue regeneration. Mesenchymal stem cells (MSCs) isolated from bone marrow have the potential for multilineage differentiation. The purpose of this study was to examine whether auto-transplantation of MSCs into periodontal osseous defects would be useful for periodontal tissue regeneration. Methods: Bone marrow MSCs were isolated from beagle dogs and expanded in vitro. The expanded MSCs were mixed with atelocollagen (2% type I collagen) at final concentrations of 2 x 10(6), 5 x 10(6), 1 x 10(7), or 2 x 10(7) cells/ml, and auto-transplanted into experimental Class III defects. Atelocollagen alone was implanted into the defects as a control. Periodontal tissue healing was evaluated by histological and morphometric analyses 1 month after transplantation. Results: The defects were regenerated with cementum, periodontal ligament, and alveolar bone in the MSC-atelocollagen groups. Less periodontal tissue regeneration was observed in the control group compared to the MSC-atelocollagen groups. Morphometric analysis revealed that the percentage of new cementum length in the 5 x 10(6) and 2 x 10(7) cells/ml groups and the percentage of new bone area in the 2 x 10(7) cells/ml group were significantly higher than in the control group (P < 0.01). Conclusion: These findings suggest that auto-transplantation of bone marrow mesenchymal stem cells is a novel option for periodontal tissue regeneration.