Biomedical Applications of Dental and Oral-Derived Stem Cells

To date, the oral cavity has yielded a diverse menagerie of adult stem cells that includes dental pulp stem cells (DPSCs), dental follicle stem cells (DFSCs), stem cells from apical papilla (SCAP), stem cells from human exfoliated deciduous teeth (SHED), periodontal ligament stem cells (PDLSCs), and gingival mesenchymal stem cells (GMSCs). These stem cells have various useful applications in clinical dentistry that is dental pulp regeneration after root canal treatment, osseous integration of titanium implants, and maxillofacial and periodontal regeneration. Stem cells-based approaches in clinical dentistry are reviewed by D. Hughes and B. Song, as well as S. Miran et al. within this special issue. Despite their common embryonic origin from the cranial neural crest and their similar fibroblastic morphology within in vitro culture, these dental and oral-derived adult stem cell populations exhibit much divergent characteristics (i.e., differences in their plasticity and proliferative potential) and express variable cell surface markers and transcription factors. In this special issue, C.-M. Kang et al. compared the tran-scriptional profile of human DPSCs and umbilical cord stem cells (UCSCs) with microarray and qRT-PCR techniques and found similar expression levels of the various canonical mesenchymal stem cell markers. However, gene ontology analyses revealed significant differences in the expression of genes related to cell proliferation, angiogenesis, immune responses, growth factor activities, and signal transduction, between DPSCs and UCSCs, which could indicate divergent propensity to differentiate into various lineages. Dental and oral-derived stem cells have a number of advantages over other more commonly utilized sources of adult stem cells. Compared to the invasive surgical procedure required for obtaining mesenchymal stem cells from bone marrow, these adult stem cells are readily isolated from biological waste produced during routine dental treatment (i.e., extraction of impacted third molars and deciduous teeth). Several studies have reported that dental and oral stem cells such as SHED possess much more extensive multidif-ferentiation potential and proliferative capacity compared to other adult stem cells. This is extensively discussed in a review on SHED by V. Rosa et al. within this special issue. Even more surprising are reports of the expression of pluripotency markers such as OCT4, MYC, and SOX2 by some dental and oral-derived stem cells, which are not usually expressed in most other adult stem cell types. Expression of these markers might be indicative of the more extensive plasticity and multilineage differentiation potential of dental and oral-derived stem cells when compared to other sources of …