ABSTRACT
BACKGROUND: Recently, there have been an increased number of basic and clinical reports indicating the superior potential of bone marrow-derived mesenchymal stem cells (MSCs) for tissue regeneration. In periodontal treatment, previous animal studies indicated that autotransplantation of bone marrow MSCs into experimental periodontal defects enhanced periodontal tissue regeneration. However, mechanisms for periodontal tissue regeneration with MSCs are still unclear. The purpose of this study was to elucidate the behavior of transplanted MSCs in periodontal defects. METHODS: Bone marrow MSCs were isolated from beagle dogs, labeled with green fluorescent protein (GFP), and expanded in vitro. The expanded MSCs were mixed with atelocollagen (2% type I collagen) at final concentrations of 2 x 10(7) cells/ml and transplanted into experimental Class III periodontal defects. Localizations of GFP and proliferating cell nuclear antigen (PCNA)-positive cells were evaluated by immunohistochemical analysis. RESULTS: Four weeks after transplantation, the periodontal defects were almost regenerated with periodontal tissue. Cementoblasts, osteoblasts, osteocytes, and fibroblasts of the regenerated periodontal tissue were positive with GFP. PCNA-positive cells were present in regenerating connective tissue. CONCLUSION: These findings suggest that transplanted mesenchymal stem cells could survive and differentiate into periodontal tissue cells, resulting in enhancement of periodontal tissue regeneration.
Subject(s)
Alveolar Process/surgery , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/physiology , Animals , Bone Marrow Cells/cytology , Bone Regeneration/physiology , Cattle , Cell Differentiation/physiology , Dogs , Female , Green Fluorescent Proteins , Proliferating Cell Nuclear AntigenABSTRACT
To address whether brain-derived neurotrophic factor (BDNF) could be involved in periodontal tissue regeneration, we examined the effects of BDNF on proliferation and the expression of bone (cementum)- related proteins (osteopontin, bone morphogenetic protein [BMP]-2, type I collagen, alkaline phosphatase [ALPase], and osteocalcin) in cultures of human periodontal ligament (HPL) cells, which are thought to be prerequisite for periodontal tissue regeneration, and on proliferation and angiogenesis in human endothelial cells. Furthermore, we examined the effect of BDNF on the regeneration of periodontal tissues in experimentally induced periodontal defects in dogs. BDNF elevated the expression of ALPase and osteocalcin mRNAs and increased the synthesis of osteopontin, BMP-2, and type I collagen DNA in HPL cells. BDNF stimulated mRNA expression of vascular endothelial growth factor-B and tenascin-X, and proliferation and angiogenesis in human endothelial cells. In vivo studies showed that BDNF stimulated the formation of new alveolar bone cementum and connective new fibers, which were inserted into the newly formed cementum and bone. BDNF also stimulated blood capillary formation. These findings suggest that the regulation of functioning of periodontal ligament cells and endothelial cells by BDNF results in the promotion of periodontal tissue regeneration.
Subject(s)
Brain-Derived Neurotrophic Factor/pharmacology , Periodontal Ligament/cytology , Periodontal Ligament/physiology , Regeneration/drug effects , Alkaline Phosphatase/metabolism , Animals , Bone Morphogenetic Protein 2 , Bone Morphogenetic Proteins/analysis , Bone Morphogenetic Proteins/metabolism , Cell Proliferation/drug effects , Cells, Cultured , Coculture Techniques , Collagen Type I/metabolism , DNA/biosynthesis , Dental Cementum/cytology , Dental Cementum/drug effects , Dental Cementum/enzymology , Dental Cementum/metabolism , Dogs , Dose-Response Relationship, Drug , Endothelium, Vascular/cytology , Endothelium, Vascular/physiology , Female , Fibroblasts/cytology , Fibroblasts/metabolism , Fluorescent Antibody Technique, Indirect , Gene Expression Regulation/drug effects , Humans , Immunohistochemistry , Neovascularization, Physiologic/drug effects , Organ Culture Techniques , Osteocalcin/metabolism , Osteopontin , Periodontal Ligament/drug effects , Procollagen/analysis , Procollagen/metabolism , RNA, Messenger/metabolism , Sialoglycoproteins/analysis , Sialoglycoproteins/metabolism , Skin/cytology , Tenascin/metabolism , Time Factors , Transforming Growth Factor beta/analysis , Transforming Growth Factor beta/metabolism , Umbilical Veins/cytologyABSTRACT
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.
