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

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