Pluripotent stem cells isolated from human amniotic fluid and differentiation into pancreatic β-cells

Human amniotic fluid (HAF) contains multipotent stem cells [amniotic fluid-derived stem cells (AFSC)] which can differentiate into a variety of different cell types. Recently, we demonstrated that obestatin, a peptide encoded by the ghrelin gene, exerts anti-apoptotic effects in pancreatic β-cells and human islets and increases the expression of genes involved in β-cells differentiation. We investigated whether: 1) AFSC would differentiate into pancreatic β-cells and 2) obestatin would increase β-cells differentiation from AFSC. Fluorescence-activated cell sorting analysis and immunocytochemical staining showed the presence of mesenchymal and endothelial markers in AFSC. Real-time PCR evidenced the expression of Octamer binding transcription factor 4 (OCT-4), a marker of pluripotency, during the early differentiation phase. However, the β-cells differentiation marker duodenal homeobox factor-1 (PDX-1) could not be detected. Obestatin increased OCT-4 expression but had no effect on β-cells differentiation. These results suggest that, at least under the experimental conditions used in this study, AFSC do not differentiate into β-cells and obestatin has no additional effect.