- Activin A and Glucose Derived Human Pancreatic Ductal Cells into Insulin-producing Cells.
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Seung Hyun Hong, Chul Han, Hyo Sup Kim, Mi Kyung Park, Young Jin Lee, Jae Hoon Jeong, Yong Ki Min, Myung Shik Lee, Kwang Won Kim, Moon Kyu Lee
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Korean Diabetes J. 2007;31(1):44-50. Published online January 1, 2007
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DOI: https://doi.org/10.4093/jkda.2007.31.1.44
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 Abstract
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- BACKGROUND
Cellular replacement therapy holds promise for the treatment of diabetes mellitus but donor tissue is severely limited. Human postnatal pancreatic ductal cells are a potential source of new beta cells. Therefore, we investigated the potential of human pancreatic ductal cells could be differentiated into endocrine cells that would be capable of secreting insulin in response to glucose. METHODS: Cell fractions enriched with pancreatic ductal cells after human islet isolation were treated with streptozotocin to remove residual beta cells, grown in monolayer culture, changed the media for differentiation in the presence of activin A and glucose, supplemented with 10% FCS. The differentiation markers, insulin secretion and cell proliferation were examined. RESULT: No insulin was detectable in cell preparations after 5 days of treatment with streptozotocin. In monolayer culture, 80% of the streptozotocin-treated pancreatic ductal cells expressed cytokeratin-19. Cell cultures with a high proportion of cytokeratin-19 cells had greater plasticity for differentiation into cells with phenotypic and functional markers of beta cells. This property were significantly enhanced by treatment of activin A and glucose. The differentiated human pancreatic ductal cells secreted insulin sensitively responded with high glucose. CONCLUSION: Human pancreatic ductal cells are a potential source of new glucose -induced insulin producing cells that may be developed further for clinical use. Therefore, the present data support a possible role for human adult pancreatic ductal cells, following expansion and differentiation, as a source of insulin by transplantation cells to type I diabetes patients.
- Thiazolidinediones on Insulin Resistance and Insulin Secretion in Obese Diabetic OLETF Rats.
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Jung hyun Noh, Seung hyun Hong, Kyoung hee Lee, Kyoung Min Min, Tae young Yang, Myung shik Lee, Kwang won Kim, Moon kyu Lee
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Korean Diabetes J. 2007;31(1):33-43. Published online January 1, 2007
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DOI: https://doi.org/10.4093/jkda.2007.31.1.33
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Abstract
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- BACKGROUND
Thiazolidinediones are synthetic peroxisome proliferator-activated receptor-gamma agonists that decrease insulin resistance but, as in vitro and in vivo studies suggest, may have direct beneficial effects on pancreatic beta cells. Here, we investigated the effects of thiazolidinediones (TZDs) on the insulin resistance, beta-cell mass and insulin secretion in obese diabetic OLETF rats. METHODS: We studied insulin resistance (by hyperinsulinemic euglycemic clamp) and insulin secretion (by hyperglycemic clamp) in TZDs administered OLETF and LETO rats. Histologic alterations of the islets were observed and beta-cell mass was also measured by point counting method. RESULTS: Chronic administration of troglitazone (TGZ, 0.15%) or pioglitazone (PGZ, 0.02%) prevented the development of glucose intolerance in OLETF rats, as assessed by oral glucose tolerance test. There was significant difference in submaximal glucose infusion rate between TGZ-treated and untreated OLETF rats during euglycemic clamp studies at 24 weeks of age. At 16 and 24 weeks of ages, beta-cell mass significantly increased in TGZ-treated OLETF rats compared to untreated animals. At 19 weeks and 30 weeks of age, first-phase insulin secretion was not different in PGZ-treated OLETF rats from untreated OLETF rats during hyperglycemic clamp study. At 30 weeks of age, late-phase insulin secretion was decreased in PGZ-treated OLETF rats compared to untreated OLETF rats. The expression of alpha-smooth muscle actin, a marker of activated pancreatic stellate cells that are involved in the fibrosis of the pancreas, in the islets was suppressed by TGZ treatment at 24 weeks of age. CONCLUSION: The treatment of TGZ prevented the development of diabetes, and increased insulin sensitivity and pancreatic beta-cell mass in OLETF rats. These results might be related with the suppression of pancreatic stellate cells. Insulin secretion was not affected by PGZ treatment.
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