Mesenchymal Stem Cells Derived from Human Exocrine Pancreas Spontaneously Express Pancreas Progenitor-Cell Markers in a Cell-Passage-Dependent Manner

Figure 1

In vitro culture of adult human exocrine pancreas cells. (a) Separated exocrine cells from adult pancreas tissue were suspension cultured on nontissue culture plate for 3 days, resulting in aggregation of single exocrine cells into clusters. (b) Exocrine clusters attached to new tissue culture plates rapidly proliferated into a monolayer. (c) After 3 days of monolayer culturing, the majority of exocrine cells displayed epithelial-like morphology and grew in tight clusters. (d) Increasing culture incubation times resulted in morphology changes in some epithelial-like cells; specifically (e) cells located outside of clusters acquired a fibroblast-like morphology and (f) proliferated alongside the epithelial-like cells. (g) Insulin-positive cells were not detected in epithelial-like exocrine cells at culture day 4; however, (h) glucagon-positive cells were detected. (i, j) A majority of exocrine cells exhibited positive-staining results for amylase and CA19-9. (k) Detection of pancreatic cell markers for insulin, glucagon, amylase, and cytokeratin 19 mRNA in exocrine cells on culture days 2, 4, and 6. Amylase mRNA expression decreased over the culture period and was not observed at culture day 6, whereas cytokeratin 19 mRNA expression was continuously detected up to culture day 6.

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