Odontogenic capability: bone marrow stromal stem cells versus dental pulp stem cells

Background information. Although adult bone-marrow-derived cell populations have been used to make teeth when recombined with embryonic oral epithelium, the differences between dental and non-dental stem-cell-mediated odontogenesis remain an open question. Results. STRO-1(+) (stromal precursor cell marker) DPSCs (dental pulp stem cells) and BMSSCs (bone marrow stromal stem cells) were isolated from rat dental pulp and bone marrow respectively by magnetic-activated cell-sorting techniques. Their odontogenic capacity was compared under the same inductive microenvironment produced by ABCs (apical bud cells) from 2-day-old rat incisors. Co-cultured DPSCs/ABCs in vitro showed more active odontogenic differentiation ability than mixed BMSSCs/ABCs, as indicated by the accelerated matrix mineralization, up-regulated alkaline phosphatase activity, cell-cycle modification, and the expression of tooth-specific proteins and genes. After cultured for 14 days in the renal capsules of rat hosts, recombined DPSC/ABC pellets formed typical tooth-shaped tissues with balanced amelogenesis and dentinogenesis, whereas BMSSC/ABC recombinants developed into atypical dentin-pulp complexes without enamel formation. DPSC and BMSSC pellets in vivo produced osteodentin-like structures and fibrous connective tissues respectively. Conclusions. DPSCs presented more striking odontogenic capability than BMSSCs under the induction of postnatal ABCs. This report provides critical insights into the selection of candidate cells for tooth regeneration between dental and non-dental stem cell populations.