Expression of Pancreatic Endocrine Markers by Mesenchymal Stem Cells From Human Umbilical Cord Vein

Background. Mesenchymal stem cells (MSCs) from human umbilical cord vein have great potential for use in cell therapy because of their ease of isolation, expansion, and differentiation, in addition to their relative acceptance from the ethical point of view. Obtaining the umbilical cord at birth does not present any risk to either mother or child. Objective. To isolate and promote in vitro expansion and differentiation of MSCs from human umbilical cord vein into cells with a pancreatic endocrine phenotype. Methods. Mesenchymal stem cells obtained from human umbilical cord vein via collagenase digestion were characterized at cytochemistry and fluorescent-activated cell sorting, and expanded in vitro. Differentiation of MSCs into an endocrine phenotype was induced using high-glucose (23 mmol/L) medium containing nicotinamide, exendin-4, and 2-mercaptoethanol. Expression of insulin, somatostatin, glucagon, and pancreatic and duodenal homeobox 1 was analyzed using immunofluorescence. Results. Cells isolated from the umbilical cord vein were MSCs as confirmed at cytochemistry and fluorescent-activated cell sorting. Expression of somatostatin, glucagon, and pancreatic and duodenal homeobox 1 by differentiated cells was demonstrated using immunofluorescence. Insulin was not expressed. Conclusions. The MSC differentiation protocol used in the present study induced expression of some endocrine markers. Insulin was not produced by these cells, probably because of incomplete induction of differentiation.

Expression of Pancreatic Endocrine Markers by Prolactin-Treated Rat Bone Marrow Mesenchymal Stem Cells

Background. Mesenchymal stem cells (MSCs) are an attractive source for generation of cells with beta-cell properties. Previous studies have demonstrated the ability of prolactin to induce an increase in beta-cell mass and maturation, which suggests beneficial effects of its use in MSC differentiation protocols. Objective. To evaluate the expression of endocrine differentiation markers in rat MSCs treated in vitro with prolactin. Methods. Mesenchymal stem cells from bone marrow of Wistar rats were isolated, expanded, and characterized. Differentiation of MSCs was induced in medium containing 23 mmol/L of glucose, and nicotinamide, 2-mercaptoethanol, and exendin-4, in the presence or absence of 500 ng/mL of rat recombinant prolactin. Expression of endocrine markers and prolactin receptor genes was evaluated using real-time polymerase chain reaction, and compared between culture stages and presence vs absence of prolactin in the culture medium. Expression of insulin, somatostatin, glucagon, and pancreatic and duodenal homeobox 1 was also evaluated at immunofluorescence microscopy. Results. Isolated cells were mostly MSCs, as confirmed at fluorescent-activated cell sorting and cytochemistry. Pax6, Ngn-3, Isl1, NeuroD1, Nkx2.2, and Nkx6.1 exhibited varied expression during culture stages. The long form of the prolactin receptor messenger RNA was induced in prolactin-treated cultures (P < .05). The somatostatin gene was induced in early stages of differentiation (P < .05), and its expression was induced by prolactin, as confirmed using immunofluorescence. Conclusion. Culture of rat bone marrow MSCs in differentiation medium induces expression of pancreatic endocrine-specific genes, and somatostatin and prolactin receptor expression was also induced by prolactin.