Identification and Cementoblastic / Osteoblastic Differentiation of Postnatal Stem Cells from Human Periodontal Ligament
Background. Periodontal diseases that lead to the destruction of periodontal tissues, including periodontal ligament (PDL), cementum, and bone, are a major cause of tooth loss in adults and are a substantial public health burden worldwide. PDL is a specialized connective tissue that connects cementum and alveolar bone to maintain and support teeth in situ and preserve tissue homoeostasis. In this study we aimed to isolate, identify periodontal ligament stem cells and their osteoblastic/cementoblastic differentiation.
Methods. Periodontal ligament tissue was obtained from human impacted third molars (n=5) from different individuals from the oral surgery department, Department of Oral and Maxillofacial Surgery, Capital Medical University School of Stomatology (Beijing, China) following which a colony forming unit - fibroblast assay, identification of periodontal ligament stem cells (PDLSCs; STRO-1 + & CD146+) by using immunocytofluorescence and isolation of PDLSCs (STRO-1+) by using flow cytometry and cementoblastic/osteoblastic exvivo induction were performed.
Results. Mesenchymal stem cells were identified in the periodontal ligament derived by their capacity to form adherent clonogenic cell clusters. Ex-vivo expanded periodontal ligament stem cells were found to express the mesenchymal stem cell markers STRO-1 and CD146. Flow cytometric study showed that a total of 24.53% of periodontal ligament cell population stained positive for the STRO-1 antibody and of that population 1.14% were strongly positive.
Conclusions. The finding of this study indicated that some PDL cells possess crucial stem cells properties, such as self renewal and express the mesenchymal stem cell markers (STRO-1 and CD 146) on their cell surface and small round alizarin red-positive nodules formed in the PDLSC cultures after 4 weeks of induction, indicating calcium accumulation in vitro. Thus, PDL cells can be used for periodontal regenerative procedures.