Dental pulp-derived stem cells (DPSC) differentiation in vitro into odontoblast and neuronal progenitors during cell passaging is associated with alterations in cell survival and viability

Background: Mesenchymal stem cells (MSC) can be derived from a variety of adult human tissues, including dental pulp from extracted or exfoliated teeth. Some evidence suggests differences in both the quality and quantity of the dental-pulp stem cells (DPSC) obtained from differing sources, such as primary or “baby teeth” and adult, permanent teeth. Aim: To evaluate the potential to obtain DPSC from intact, vital permanent teeth, using a randomized selection of active dental patients. Methods: DPSC were extracted, isolated, cultured and characterized using microscopy and RT-PCR analysis of extracted RNA. Results: DPSC isolates were derived from 30/31 (96.8%) of tissue explants using direct outgrowth (DO); mainly giving rise to uncommitted MSC progenitors with rapid doubling times (rDT, n=25/30 or 83.3%) and positive mRNA expression of MSC markers CD44, CD24, NANOG, Oct-4 and Sox2. DPSC isolates with slower doubling times (sDT, n=3/30 or 10%) and more limited differentiation potentials resembled neural or odontoblastic progenitor cells (sDT:npc or sDT:opc), expressed neural differentiation markers CD133 and III tubulin or the odontoblastic differentiation marker, dentin sialophosphoprotein (DSPP), and had lower survival and viability rates following freezing, long-term storage and thawing. Conclusions: The need to identify potential sources of MSC to treat age-related illnesses in the current population makes it necessary to more fully explore the feasibility and potential of DPSCs extracted from adult human teeth for this newly developing field of regenerative medicine.