Conditioned medium from periapical follicle cells induces the odontogenic differentiation of stem cells from the apical papilla in vitro.

Introduction: We investigated the biological effects of conditioned medium (CM) from periapical follicle cells (PAFCs) of root-developing tooth on the proliferation and differentiation of stem cells from the apical papilla (SCAP) in vitro.

Methods: Human SCAP and PAFCs were isolated and expanded. CM from PAFCs was prepared with the primary cells. Cell cycle analysis, methyl-thiazol-diphenyltetrazolium assay, alkaline phosphatase activity, mineralization behavior, and gene expression of odontoblast phenotype SCAP cultured with or without CM from PAFCs were evaluated.

Results: In the CM-treated group, the cell growth, alkaline phosphatase activity, and mineralization of SCAP were up-regulated. The expression of dentin sialophosphoprotein, alkaline phosphatase, and osteocalcin mRNA progressively increased in SCAP treated with CM from PAFCs.

Conclusions: Our findings suggest that CM from PAFCs is able to provide a favorable odontogenic microenvironment to induce differentiation of SCAP along the odontoblast lineage.