Phenotypic, trophic, and regenerative properties of mesenchymal stem cells from different osseous tissues.

Mesenchymal stem cells (MSCs) have broad-based therapeutic potential in regenerative medicine. However, a major barrier to their clinical utility is that MSCs from different tissues are highly variable in their regenerative properties. In this study, we defined the molecular and phenotypic identities of different MSC populations from different osseous tissue sites of different patients and, additionally, determined their respective regenerative properties. MSCs from 6 patients were isolated from either bone marrow of the iliac crest (BMSCs) or alveolar bone tissue (aBMSCs), and flow cytometry revealed that regardless of the tissue source, MSC immunotypes had the same expression of MSC markers CD73, CD90, and CD105. However, transcriptomic analyses revealed 589 genes differentially expressed (DE) between BMSCs and aBMSCs, including eightfold higher levels of bone morphogenetic protein 4 (BMP-4) in aBMSCs. In striking contrast, gene expression of MSCs derived from the same tissue, but between different patients (i.e., BMSCs to BMSCs, aBMSCs to aBMSCs), showed only 38 DE BMSC genes and 51 DE aBMSC genes. A protein array showed that aBMSC and BMSC produced equivalent levels of angiogenic cytokines; however, when placed in angiogenesis model systems, aBMSCs induced significantly more capillaries in vitro and in vivo. Finally, cell transplantation of MSCS into osseous defects showed that the bone regenerative capacity of aBMSCs was significantly greater than that of BMSCs. This study is the first to link the molecular, phenotypic, and regenerative properties of different MSCs from different patients and provides novel insights toward MSC differences based on the osseous tissue origin.

Dental Pulp Tissue Regeneration Using Dental Pulp Stem Cells Isolated and Expanded in Human Serum.

INTRODUCTION: Dental pulp-derived stem cells (DPSCs) have the potential to regenerate dentin and dental pulp tissue because of their differentiation capacity and angiogenic properties. However, for regenerative approaches to gain regulatory and clinical acceptance, protocols are needed to determine more feasible ways to cultivate DPSCs, namely, without the use of xenogeneic-derived components (animal sera) and exogenous growth factors. METHODS: In this study, human DPSCs were isolated from third molars and expanded in standard culture conditions containing fetal bovine serum (DPSCs-FBS) or conditions containing human serum (DPSCs-HS). After cell characterization and evaluation of their angiogenic secretome, DPSCs were seeded in tooth slice/scaffolds and implanted subcutaneously into immunodeficient mice. After 30 days, tooth slices were retrieved and evaluated for dental pulp tissue regeneration. Immunohistochemistry and confocal microscopy were used to quantify blood vessel formation and evaluate predentin and dentin formation. RESULTS: After culture, DPSCs-HS produced concentrations of angiogenic growth factors equivalent to DPSCs-FBS. Additionally, in DPSCs-HS, several angiogenic factors were produced in at least 1-fold higher concentrations than in DPSCs-FBS. In vivo, it was determined that DPSCs-HS produced a robust angiogenic response and regeneration of dentin equivalent to DPSCs-FBS. CONCLUSIONS: These findings show that DPSCs can be isolated and expanded to clinical scale numbers in media devoid of animal serum or exogenous growth factors and still maintain their pulp regenerative properties. The implications of these findings are significant for further development of clinical protocols using DPSCs in cell therapies.