Multipotent Mesenchymal Stem Cells with immunosuppressive activity can be easily isolated from Dental Pulp

Background. Bone marrow mesenchymal cells (MSCs) are currently being investigated in preclinical and clinical settings because of their multipotent differentiative capacity, or alternatively, their immunosuppressive function. The aim of this study was to evaluate Dental Pulp (DP) as a potential source of MSCs, as compared to Bone Marrow (BM). Methods and results. Flow cytometric analysis showed that DP-MSCs and BM-MSCs were equally SH2, SH3, SH4, CD29 and CD 166 positive. However, while BM-MSCs could be differentiated in vitro into osteogenic, chondrogenic and adipogenic lineages, DP-MSCs showed osteogenic and adipocytic differentiation, but did not differentiate into chondrocytes. The in vitro proliferative kinetics of MSCs, measured by 3H-Thymidine incorporation uptake, showed that while DP-MSCs grow rapidly in vitro between day 3 and day 8 of culture and then decrease their proliferation by day 15, BM-MSCs have a stable and continuous proliferation over the same period of time. The immunosuppressive function of MSCs was then tested by co-culturing PHA-stimulated allogeneic T cells with or without MSCs for 3 days. The addition of DP-MSCs or BM-MSCs resulted in 91±4% and 75±3 % inhibition of T cell response, respectively, assessed by a 3H-Thymidine assay. Conclusions. Dental pulp is an easily accessible and efficient source of MSCs, with different kinetics and differentiation potentialities from MSCs as isolated from the bone marrow. The rapid proliferative capacity, together with the immunoregulatory characteristics, of DP-MSCs may prompt future studies aimed at using these cells in the treatment or prevention of T cell alloreactivity in hematopoietic or solid organ allogeneic transplantation.