Selection and Potentialities of Pulp Stem/Progenitor Cells

Tissue engineering and regeneration offer exciting opportunities for new treatment modalities for dental tissue injury and disease, but suitable stem/progenitor cell sources are required. Because of the cell heterogeneity of pulp, these stem/progenitor cells probably comprise a relatively small proportion of a more diverse cell population. Objective: to develop strategies for the selection and enrichment of stem/progenitor cells from pulp with dentinogenic potentiality. Methods: Trypsin-dissociated rat (young adult male Wistar) incisor pulp cells were grown to confluence in αMEM medium with 10% FCS, glutamine and antibiotic supplements and isolated prior to examination of possible markers (α-smooth muscle actin, CD44, nestin and p75NTR) for selection of stem/progenitor cells by Fluorescence-Activated Cell Sorting (FACS). Subsequently, Magnetic Activated Cell Sorting (MACS) was used to select cells on the basis of the surface marker p75NTR. The dentinogenic potentiality of the cells was investigated by treatment with dentinogenic inductive medium based on morphological and gene expression (sqRT-PCR) criteria. Results: p75NTR+ cells represented a small proportion of the total pulp population and provided a greater level of discrimination in cell selection than the other markers examined. A diverse panel of gene markers confirmed that p75NTR was discriminatory in its selection of cells and that after dentinogenic induction, the population was enriched in stem/progenitor cells capable of differentiation along the odontoblast lineage. Conclusions: Cell selection using p75NTR provides enrichment of stem/progenitor cells from pulp with dentinogenic potentiality and may be valuable in tissue engineering applications.