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BACKGROUND: Glucose is an important factor on differentiation of pancreatic duct stem cells, it relates to the quantity and secretion function of insulin-producing cells after differentiation.OBJECTIVE: To compare the insulin secretion capacity of the differentiated rat pancreatic stem cells induced by various glucose concentrations.METHODS: Rat stem cells were isolated and purified from pancreatic duct cells using collagenase V and Ficoll-400. These stem cells were randomly divided into 10 groups. Every group was induced to culture, proliferate, differentiate and form insulin- producing cells in vitro. The differentiation of all groups was performed in medium with different concentrations of glucose. The immunofluorescence staining was used to identify the pancreatic duct stem cells. The electrochemical luminescence method was used to detect the insulin release from stem cell differentiated islets.RESULTS AND CONCLUSION: The stimulation index of glucose 20.6, 25.6, 30.6 mmol/L groups was higher than that in other groups (P 0.05). The insulin releasing of glucose 15.6, 20.6, 25.6 groups was higher than that in other groups (P 0.05). The best insulin secretion capacity of insulin-producing cells can be gained by controlling concentration of glucose as 20.6-25.6 mmol/L when pancreatic duct stem cells differentiated into insulin-producing cells.
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Objective To investigate the potential of pancreatic stem cells (PSCs) directed differentiation in vitro, and to evaluate the effects of differentiated PSCs allograft on the treatment of diabetes.Methods The PSCs of adult Wistar rats were separated and purified in vitro. The surface of PSCs was determined by immunofluorescence staining, and then it was stimulated by hepatocyte growth factor (HGF) and nicotinamide to induce directed differentiation. Dithizone dyeing was used to determine the islet-like cells after induction, and ELISA staining method was used to detect the insulin levels. Streptozotocin peritoneal injection was used to induce the diabetic rat mode. 40 rats were randomly allocated into pancreatic islet cells allograft group (experiment group) and placebo group. The serum insulin and glucose levels 1 d before transplantation and 1, 2, 3, 4 week after transplantation were measured. Results PSCs of adult Wistar rats were successfully obtained, and the expression of CK19, Pdx-1 and Nestin on cell surface was positive. Dithizone dyeing for directed differentiation cells showed brownish red color. The cells could express and secrete insulin after hyperglycaemia stimulation. The serum insulin and glucose levels 4 week after transplantation were (11.41 ±1.52) mU/L and (8.22 ± 2.7) mmol/L, which were (9.30 ± 1.56) mU/L and (12.23 ± 3.8) mmol/L in the placebo group, and difference was statistically significant (P＜0.05). Conclusions PSCs can be induced and directed differentiated in vitro into islet-like clusters with insulin secretion function. And its allograft has the potential for the treatment of diabetes.
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ObjectiveTo observe the effect of mesenchymal stem cells (MSCs) on enhancing rat islets viability and function in vitro by a pretransplant co-culture.Methods4-week-old Wistar rats were used as donors, bone mesenchymal stem cells were isolated and subcultured. Islets of Wistar rats were isolated and purified by one-step single-layer Histopaque-1077. Then islets were divided into four groups randomly, 2 groups co-cultured with mesenchymal stem cells (MSCs) (one using low-glucose medium; the other using high-glucose medium ); 2 groups were cultured alone (low-glucose medium; high-glucose medium), each group was further stratified into 3 subgroups(3, 7, 14 d); the survival and functionality of these islets were observed and evaluated. The amount of glucose stimulated secreted insulin were measured wth a rat/mouse insulin enzyme-linked immunosorbent assay (ELISA) kit and stimulation index was also calculated.ResultsCompared with those not co-cultured, islets co-cultured with MSCs demonstrated significantly higher survival rates and viability both in 3th, 7th and 14th day ( P ＜ 0. 01 ); furthermore, cocultured islets revealed higher levels of glucose stimulated insulin secretion and secretion indexes in 7th day (P＜0.01).ConclusionRat islet cells co-cultured with MSCs have longer in vitro survival and better functions.
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Objective To investigate the expressions and the clinical significance of nectin-4 in pancreatic carcinoma and the relationship with clinicopathological features. Methods Immunohistocbemical techniques were used to detect nectin-4 expression in pancreatic carcinoma tissues (n = 40) and normal pancreatic tissues (n = 12 ), and the relationship between the expressions and clinicopathological parameters was analyzed. Results The IOD and area of nectin-4 were 2. 43 ± 0.75 and 9. 73 ± 1.86 in pancreatic carcinoma tissues, which were significantly higher than those in the normal pancreatic tissues( P ＜ 0.01 ).The expression of nectin-4 was not correlated with patients demographics ( P ＞ 0.05 ), and the protein expression was correlated with histopathologic grade ( P ＜ 0.01 ) and lymph metastasis ( P ＜ 0.05 ).Conclusions The high expression of nectin-4 in pancreatic carcinoma tissues suggests that its high expression may be correlated with the malignant degree of the carcinoma. nectin-4 can be considered as a reference index of differentiation, metastasis and prognosis in pancreatic carcinoma.