In vitro analysis of mesenchymal stem cells derived from human teeth and bone marrow

Mesenchymal stem cells derived from human teeth and bone marrow have been characterized by many research groups, but demonstrate inconsistent cellular phenotypes or functions, partly because of differences in culture methodology. Therefore, our aims were to resolve these inconsistencies and discuss the potential uses of these cells in research/clinical applications. We isolated and characterized dental stem cells (DSCs) from the dental pulp, periodontal ligament, apical papilla (APSCs) and dental follicle (DFSCs) of mature and immature teeth, along with bone marrow-derived stem cells (BMSCs) from the iliac crest. We compared the clonogenic and proliferative potentials of these cells in terms of colony-forming efficiency, proliferation potential, population doubling time and cell cycle. All DSCs, particularly APSCs and DFSCs, possessed greater proliferative potential than BMSCs. All stem cells expressed typical mesenchymal and embryonic markers, and developed alizarin red-positive mineralization nodules and Oil red O-positive lipid droplets when cultured in osteogenic and adipogenic media, respectively. Immunocytochemistry revealed that all stem cells developed neuronal markers when cultured in a control medium without neural inductive supplements. After 7 days of neurogenic culture, the differentiated cells showed a transition from fibroblast-like to neuron-like cell bodies with long processes, suggesting that the stem cells differentiated into mature neurons. Karyotyping confirmed that the stem cells maintained a normal karyotype and were chromosomally stable. Our results provide new insights into the physiological properties of stem cells with a normal karyotype and indicate that DSCs are appropriate for basic research and clinical applications.