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.

Tooth storage, dental pulp stem cell isolation, and clinical scale expansion without animal serum.

INTRODUCTION: Dental pulp stem cells (DPSCs) have therapeutic potential for dentin and dental pulp regeneration. For regenerative approaches to gain clinical acceptance, protocols are needed to determine feasible ways to store teeth, isolate DPSCs, and expand them to clinical scale numbers. METHODS: In this study, 32 third molars were obtained from patients and immediately placed in saline or tissue culture medium followed by overnight storage at 4°C or immediate isolation of DPSCs. Upon isolation, cells were expanded in medium containing either fetal bovine serum (FBS) or human serum (HS). Cell proliferation (population doubling time [PDT]), cell surface marker expression, and multipotency were compared between DPSCs in FBS and DPSCs in HS. RESULTS: The time frame of storage and storage medium did not affect the ability to isolate DPSCs. However, using HS instead of FBS in the initial isolation of DPSCs significantly decreased (P < .01) the isolation success rate from 89% (FBS) to 23% (HS). Yet, incorporating fibronectin in the DPSC initial isolation (using HS) significantly (P < .01) increased the isolation success rate to 83%. Interestingly, it was found that the proliferation rate was significantly (P < .05) higher for DPSCs in HS (PDT = 1.59 ± 0.46) than that for DPSCs in FBS (PDT = 2.84 ± 2.5). Finally, there was no difference in the expression of CD73, CD90, CD105, or multipotency (as measured by osteogenic, adipogenic, and chondrogenic differentiation) between DPSCs in FBS and DPSCs in HS. CONCLUSIONS: These findings show a clinically feasible method of storing third molars for the isolation of DPSCs. Additionally, DPSCs can be isolated and expanded to clinical scale numbers in media devoid of FBS and still maintain their phenotypic properties.