Stromal phenotype of dental follicle stem cells

It has been suggested that stem/progenitor cells exist in dental tissue. This study identified adult mesenchymal stem/stromal cell-like populations in the dental follicle of human impacted third molars.The immunohistochemical analysis, of dental follicle using known stem-cell markers: Cytokeratins (AE1-AE3), Smooth Muscle Actin, Ki-67, CD34, CD44, CD45, CD56, and CD133. A positive reaction for at least one of the markers typical of stromal phenotype (CD56, CD44 and CD271) was observed in seven cases . Interestingly, all positive cases showed coexpression of CD44 and CD56, except for one case which was CD56 positive and CD44 negative. Immunohistochemical reaction was negative in all 27 cases for Ki-67, Cytokeratins, Smooth Muscle Actin, CD34, CD133 and CD45. The association: negative for CD34, CD45, CD133, and positive for CD44, CD56 (markers of a subpopulation of stem cells from bone marrow) suggests these may be quiescent mesenchymal stem cells, a hypothesis supported by the negativity of Ki-67 (proliferative index). Our results are compatible with the identification of immature fibroblast cells with phenotypic features of stromal stem cells in the dental follicle.