Cellular Properties and Expression of Pluripotent Markers in Human Dental Pulp Stem Cells Cultured in Serum-Free Medium ZC05-ZC09
Dr. Mohana Kumar Basavaraajappa,
Associate Professor, Department of Nitte University Centre for Stem Cell Research and Regenerative Medicine, K. S. Hegde Medical Academy, Nitte (Deemed to be University), Deralakatte-575018, Mangaluru, Karnataka, India.
Introduction: The standard isolation and expansion of human Dental Pulp Stem Cells (DPSCs) under invitro conditions normally involve the usage of Fetal Bovine Serum (FBS). However, its animal-origin poses possible concerns for clinically relevant procedures. This critical issue compels the use of Xenogeneic-Free (XF) or human-origin alternatives to FBS for culture expansion and differentiation of DPSCs to determine the usefulness for translating into therapeutic clinical applications.
Aim: To evaluate the cellular characteristics and expression of pluripotent markers in DPSCs cultured using Serum-Containing Medium (SCM-DPSCs) and Serum-Free Medium (SFM-DPSCs).
Materials and Methods: This in-vitro descriptive study was conducted at NITTE (Deemed to be University), Mangaluru, Karnataka, India, from June 2019 to August 2020. DPSCs were isolated from impacted third molars. The culture expanded DPSCs in serum-containing and serum-free media were analysed on their morphology, viability, proliferation rate, Population Doubling Time (PDT), Alkaline Phosphatase (ALP) activity, cell surface markers expression, osteogenic and adipogenic potential, and the relative expression of selected pluripotent genes.
Results: The primary culture of DPSCs established in SCM and SFM showed spindle shaped fibroblastic morphology with >80% viability from passage 1 (P1) to P4. A significant (p-value<0.05) difference in the proliferation rates in terms of cell numbers between SCM-DPSCs and SFM-DPSCs was observed (day 6: 3×105 vs 0.8×105; day 9: 5.8×105 vs 1.27×105; day 12: 7.8×105 vs 1.56×105, respectively). The average PDT values recorded in SCM- and SFM-DPSCs were 44.33 hours and 58.41 hours, respectively. A slightly higher expression of ALP activity was observed in SCM-DPSCs than in SFM-DPSCs. Flow cytometry analysis showed that both DPSCs were positive for CD29, CD73, CD90, and negative for CD34 and CD45. The expression of OCT4 and NANOG was relatively higher in SCM-DPSCs compared to SFM-DPSCs. Further, SCM-DPSCs showed the higher levels of SOX2 and SSEA4, but did not exhibit any significant differences in their expression levels.
Conclusion: The results showed that DPSCs in FBS displayed better growth kinetics and stemness markers expression along with more propensities towards lineage differentiation. SFM can be used to establish and expand DPSCs with characteristics of multipotent stem cells, but needs further research for its optimisation.