Donor-matched comparison of dental pulp stem cells and bone marrow-derived mesenchymal stem cells in a rat model

Dental pulp stem cells (DPSCs) have drawn much interest for the regeneration of mineralized tissues, and several studies have compared DPSCs to bone marrow-derived mesenchymal stem cells (BMMSCs). However, conflicting results, possibly due to donor-associated variability, have been published and the regenerative potential of DPSCs is currently unclear. In the present study we have sought to address this problem using a donor-matched experimental design to robustly compare the biological properties of DPSCs and BMMSCs. All experiments were performed using cells isolated from a single adult Sprague-Dawley rat. Our results show that DPSCs and BMMSCs had similar morphologies and flow cytometry profiles, were capable of forming colonies in vitro and were capable of osteogenic, chondrogenic and adipogenic differentiation. However, quantitative comparisons revealed that DPSCs had a faster population doubling time and a higher percentage of stem/progenitor cells in the population, as determined by clonogenic assays. Furthermore, while both cell populations formed mineral in vitro, DPSCs had significantly higher alkaline phosphatase activity than BMMSCs after 3 weeks in osteogenic medium. These data show several key differences between DPSCs and BMMSCs and support the possibility of using DPSCs for mineralized tissue regeneration.