Periodontal Ligament Stem Cells in Regenerative Dentistry for Periodontal Tissues

Abstract

The ideal periodontal treatment is regenerating functional periodontal tissues destroyed by severe periodontitis. The tissue engineering triad includes stem cells, biological signals, and cell-seeded scaffold that are considered to be essential for tissue regeneration. Periodontal ligament (PDL) tissue contains a stem cell population, periodontal ligament stem cells (PDLSC), that is derived the neural crest tissue. PDLSC demonstrate high proliferative capacity and multipotency that make them a highly promising stem cell population for use in the regeneration of damaged periodontal tissues. Here, we review the current understanding of the features and functions of PDLSC. Keywords: Periodontal ligament; Regeneration; Stem cells; Periodontal tissues;Biological signals of the periodontium and around 50% of adults suffer from its moderate and severe generalized form [2] Severe generalized form of periodontitis induces the destruction of PDL tissues including the loss of collagen fiber attachment between alveolar bones to the cementum surface and the progression of alveolar bone resorption, which is a principal cause for tooth loss [3]. Therefore, the regeneration of PDL tissues damaged by advanced periodontitis would be important to maintain healthy teeth for a lifetime. Stem cells are self-sustaining by replicating themselves and show the potential to differentiate into various cell types. Many researchers believe that these features of stem cells may offer benefits in the field of cell-based regenerative therapy. PDL stem cells (PDLSC) are a kind of dental stem cells identified in PDL tissues and originate from the neural crest tissue. They also have the potential to differentiate into a variety of PDL cells including fibroblasts, osteoblasts, cementoblasts, enthothelial cells, neural cells [4,5]. The aim of this review is to summarize the key topics of PDLSC including their properties, characteristics, current research, and future potential for PDLSC-based regenerative periodontal therapies. Characteristic of periodontal ligament stem cellsThe stem/progenitor cell populations have been revealed to be derived from endosteal spaces that are enriched immmature cells [6]. These cells have the potential to differentiate into multipule PDL cell including fibroblasts, osteoblasts, and cementoblasts that are principal for maintainance and homeostasis of PDL tissues [7]. Seo et al. [8] first isolated PDLSC from the PDL tissue of extracted human third molar teeth [8]. Many types of MSCrelated cell surface markers such as CD10, CD13, CD26, CD29, CD44, CD71, CD73, CD90, CD105, CD106, CD146, CD166, CD349, STRO-1, STRO-3, and TNAP/MSCA-1 have been identified in PDLSC [9]. PDLSC formed mineralized nodules with the increase of bone-related gene expression when they were cultured in osteogenic medium [8]. Additionally, PDLSC injected into calvarial defect model mice demonstrated the new bone formation within the defects [10], suggesting that PDLSC have the capacity to differentiate into osteoblasts. PDLSC was also induced...