The establishment of a chemically defined serum-free culture system for human dental pulp stem cells.

The concept of establishing a dental stem cell (DSC) bank for oral and maxillofacial regeneration has become of great interest but it remains at a primitive stage. The routine application of serum-containing conditions for human DSC (hDSC) culture is in great controversy considering that the animal-originated serum can cause serious ethical concerns and lead to increasingly irrelevant variables, errors, and poor repeatability of experiment results. Thus, this study aimed to establish a safe, stable and efficient hDSC serum-free culturing system for future DSC bank usage. Dental pulp stem cells (DPSCs) from human permanent tooth pulp were isolated, expanded, passaged, and divided into two groups according to their culture conditions: group 1 was the serum-containing medium (SCM) group; and group 2 was the serum-free Essential 8 medium (E8) group. DPSCs were characterized first, followed by cell proliferation, pluripotency, and migration study in SCM and E8 medium. Human DPSCs (hDPSCs) in E8 medium demonstrated greater proliferation, pluripotency, migration ability and less apoptosis. hDPSCs could be successfully induced to the adipogenic, osteogenic, neurogenic, and chondrogenic lineages in E8 group. Real-time polymerase chain reaction indicated that the expression of PPAR-γ, RUNX2, OCN and MAP-2 was higher in E8 group.  CONCLUSIONS: Compared with serum-containing medium, E8 medium exhitibed higher ability in maintaining the cell proliferation, pluripotency, migration, and stability. This new serum-free culture environment might be applicable for hDSC culture in the future.