Salivary Acinar-like Transdifferentiation of Mesenchymal Stem Cells: A Comparative Study

Objective: Stem cell therapy is promising to prevent radiation-induced xerostomia. Substantial improvement was found after the injection of Bone Marrow Stem Cells (BMSCs) into irradiated salivary gland of animals, and the transdifferentiation into amylase-secreting acinar-like cells was also noted after co-cultured with Salivary Acinar (SA) cells in vitro. However, there is great discomfort to harvest stem cells from bone marrow. As a more obtainable alternative for dental therapists, Adipose-Derived Stem Cells (ADSCs)have become attractive; nevertheless, the potential of ADSCs SA-like transdifferentiation has not been fully investigated. Therefore, the main objective of this study was to compare the SA-like transdifferentiation of ADSCs with that of BMSCs for the future development of salivary tissue engineering. Method: Indirect co-culture of Stem cells with SA cells was performed by using 0.4μm pore size Transwell culture inserts (Corning). Cell morphology was observed under phase-contrast microscope. The immunocytochemical analysis of α-amylase was carried out to investigate the time-dependent SA-like transdifferentiation potential of ADSCs with that of BMSCs. The amylase secretion was also quantified by indirect enzyme-linked immunosorbent assay (ELISA). Result: Morphological development into acini-like structures was found both in ADSCs and BMSCs after co-cultured for 2 weeks. Immunocytochemical analysis detected the expression of α-amylase in cytoplasm of ADSCs and BMSCs after co-cultured for 2 weeks. The α-amylase production measured by ELISA showed that both ADSCs and BMSCs can secret similar amounts of α-amylase after co-cultured with salivary acinar cells. Conclusion: In this study, we found that salivary acinar-like trandifferentiation potential of ADSCs is comparable with that of BMSCs. The results are important for the development of cellular therapy and salivary gland tissue engineering with ADSCs. The in vivo therapeutic potential of ADSCs is worthy of further study.