Phenotypic Properties of DPSCs in Human Platelet Lysate vs. FBS

Objectives: Dental pulp-derived stem cells (DPSCs) have potential as part of cell therapies to regenerate dental pulp tissue following loss of dental pulp vitality. Most traditional methods of cultivating DPSCs ex vivo use bovine serum (i.e. FBS), which, from a regulatory standpoint, limits their clinical use. Here, we test the hypothesis that DPSCs can maintain their phenotypic properties following isolation, expansion, and cryopreservation when cultivated in medium devoid animal sera.
Methods: Human DPSCs from 3^rd molars were isolated, expanded to clinical-scale numbers and cryopreserved in media containing either; 1) FBS or 2) human platelet lysate (hPL). Cell counting kit assay (CCK-8) and population doubling time (PDT) were conducted to assess the effects of hPL on proliferation of DPSCs. Finally, multipotency staining and flow cytometric analysis were conducted to assess differentiation capacity of DPSCs.
Results: Analysis of DPSC proliferation showed that there was no statistical difference in proliferation for DPSCs expanded post-cryopreservation in hPL (PDT = 2.9 ± 0.46) compared to DPSCs expanded in FBS (PDT = 2.6 ± 0.85).Flow cytometry analysis of DPSCs cultured in hPL showed high levels of MSCs markers such as CD73 (99.5%), CD90 (99.5%), and CD105 (98.9%), while showing low levels of hematopoietic cell marker CD34 (2%) and leucocyte marker CD45 (0.59%). In addition, results of multipotency staining showed that DPSCs in hPL maintain multipotent properties and could differentiate into adipocytes, osteoblasts, and chondrocytes.
Conclusions: Here, it was demonstrated that DPSCs can be isolated, expanded, and cryopreserved in media devoid animal serum without loss of viability or phenotypic properties. Further study of DPSCs angiogenic and neurogenic properties are underway as another translational step towards the use of DPSCs for dental pulp regeneration.