- The Effect of Increased Beta Cell Mass on Glucose Tolerance in Rat.
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Eun Sook Oh, Kun Ho Yoon, Sun Hee Seo, Sook Young Lee, Seung Hyun Ko, Won Young Lee, Sung Rae Kim, Moo Il Kang, Bong Yon Cha, Kwang Woo Lee, Ho Young Son, Sung Goo Kang
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Korean Diabetes J. 2000;24(6):629-640. Published online January 1, 2001
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 Abstract
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- BACKGROUND
The aim of the present study is to evaluate the effect of increased beta cell mass by continuous 96-hour 50% glucose infusion on glucose tolerance in insulin resistance state induced by high fat diet in normal Sprague-Dawley rats. METHODS: The adult Sprague-Dawley rats weighing 200-250 gm were infused with 50% glucose or 0.45% saline via external jugular vein catheter for 96 hours. The both groups of rats were then randomly stratified into the two subgroups, and fed either high fat diet (54% of energy from fat) or normal rat chow (8.6% of energy from fat) for 4 weeks. On day 28, blood was collected for measuring the serum concentration of insulin, and oral glucose tolerance test (2 gm/kg body weight) was performed after overnight fasting. The beta cell mass was counted with the morphometric point-counting technique of Weibel. RESULTS: After the 96 hour infusion, the percentage of beta cell mass was significantly increased in glucose-infused rats when compared to the saline-infused group (p=0.03) and maintained up to day 28. Body weight gains were significantly greater in glucose infused rats than those of saline infused group (Increased value of weight : 142.9+/-15.2 g in glucose infused rats vs 125.3+/-21.1 g in saline infused rats, p=0.01). In the saline infusion-high fat diet group, the number of rats with impaired glucose tolerance was higher than those of other group (p<0.005). The glucose values at 90 minute and 120 minute were higher in saline infusion-high fat diet group than in glucose infusion-high fat diet group (p< 0.05). CONCLUSION: Our findings suggest that the increased beta cell mass has a favorable effect on glucose tolerance in insulin resistance state which were evoked by high fat diet.
- Quantification of the Pancreatic -cell Mass in Normal and Type 2 Diabetic Subjects in Korea.
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Kun Ho Yoon, Seung Hyun Ko, Jung Min Lee, Sung Rae Kim, Sun Hee Seo, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang, Yong Gui Kim, In Sung Moon, Myung Deuk Lee, Dong Ku Kim, Kyo Young Lee, Chan Suk Kang, Byung Ki Kim
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Korean Diabetes J. 2000;24(5):524-532. Published online January 1, 2001
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Abstract
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There have been several reports about insulin secretory impairment in non-obese type 2 diabetic patients and even in impaired glucose tolerant subjects in Korea. Insulin secretory impairment might be induced by insufficient beta-cell mass, functional defects of beta-cells or both. To clarify the cause of impaired insulin secretion in type 2 non-obese diabetic patients in Korea, beta- cell masses were quantified in normal and type 2 diabetic subjects. METHOD: Normal pancreases were procured by 6 heart-beating non-diabetic donors under informed consent from relatives and approval of the university ethical committee. To quantify the beta cell mass and insulin content in various part of the pancreas, first we divided it into 3 parts: head, body and tail, and then each three parts were weighed and subdivided again into 8 segments equally. For diabetic patients, tissue sections were obtained from 15 partial or total pancreatectomized type 2 diabetic patients of any causes. After being fixed, tissues were immunostained using the Streptavidin-biotin-peroxidase method with anti-insulin antibody. Beta cells were counted by point count method. RESULTS: The mean value of total pancreas weight of normal subjects (n=6) was 77.1+/-14.6 g, that of mean relative volume of beta cells in the pancreas was 2.1+/- 0.9%, ranging from 1.4% to 3.1% (head 2.3+/-0.6%, body 1.8+/-0.2%, tail 2.2+/-0.4%). Mean value of total beta cell mass which was calculated from relative volume of beta-cells and weight of each portions was 1.3+/-0.3 g, ranging from 1.2 g to 1.9 g (head 0.6+/-0.3 g, body 0.4+/-0.2 g, tail 0.4+/-0.2 g). Mean insulin content per pancreas was 63.6+/-46.6 g, ranging from 27.8 to 137.2 g/pancreas (head 25.1+/- 19.1 g, body 20.8+/-15.5 g, tail 17.7+/-14.9 g). In diabetic patients, relative volume of beta cells in tissues were variable from 0.4% to 2.8% and there was good correlation between beta-cell mass and body mass index of the diabetic patients. However we can't find the correlation among relative volume of beta-cell, (r2=0.55, p<0.05) duration of diabetes and age. Remarkable heterogeneity for loss of beta-cells in the islets of diabetic patients was observed even in the same lobe of pancreas. There were no evidence of lymphocytic infiltration in the islets. CONCLUSION: Insufficient beta cell mass seems to be a main cause for insulin secretory impairment in non-obese type 2 diabetic patients in Korea.
- In Vitro Expansion and Differentiation of Islet Precursor Cells from Cultured Neonatal Porcine Pancreatic Tissue.
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Yu Bae Ahn, Kun Ho Yoon, Sun Hee Seo, Seung Hyun Ko, Ki Ho Song, Je Ho Han, Soon Jip Yoo, Hyun Sik Son, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
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Korean Diabetes J. 2000;24(3):310-322. Published online January 1, 2001
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- BACKGROUND
Neonatal porcine pancreas is an attractive alternative source for islet transplantation because of its growth potential and availability. Porcine neonatal pancreatic cell clusters (NPCCs) consist mainly of protodifferentiated cells expressing both the duct cell marker pancytokeratin and islet hormones. In this study, we investigated to expand and mature the pancreas duct cells contained in porcine NPCCs with extracellular matrix. METHODS: For NPCCs, pancreas obtained from neonatal pigs were minced, digested with collagenase and cultured overnight. Then NPCCs were further dispersed to small cell groups and cultured on HTB-9 extracellular matrix: the tissue attached and formed monolayer patches. At the 3rd and 8th days, tissue was fixed, immunostained for pancytokeratin (panCK), vimentin (VT) and islet hormones. RESULTS: During 5 days culture, the total cell numbers increased 3.2 fold on the matrix, and 1.6 fold on the sticky dish, respectively. Insulin positive cells (Ins+) were 6.0% of total cells at day 3 and increased 1.6 fold in numbers at day 8. There was significant increase in DNA content of NPCCs in monolayers on both sticky dishes and HTB-9 matrix. In contrast, insulin content of both groups decreased during culture periods. Until 8 days of culture after dispersion of porcine NPCC, most duct cells costained with panCK and VT. CONCLUSION: We observed NPCCs were composed of many of duct cells which were known to be endocrine precursor cells and monolayer culture of NPCC withextracellular matrix resulted in the proliferation and differentiation of pancreatic duct cells.
- The Changes of Expression of Intermediate Flament in Pancreatic Duct Cells During Proliferation and Differentiation after 90% Pancreatectomy in Rats.
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Seung Hyeon Ko, Kun Ho Yoon, Sun Hee Seo, Jung Min Lee, Ki Won Oh, Sang Ah Chang, Hye Soo Kim, Yoo Bae Ahn, Hyun Shik Son, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
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Korean Diabetes J. 2000;24(2):191-201. Published online January 1, 2001
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Neogenesis of the beta calls from ductal cells is the main mechanism of the increased beta cell mass after partial pancreatectomy. For the transdifferentiation from the duct cells to the beta cells, de-differentiation of the duct cells is needed because duct cells are also terminally differentiated cells already. But there was no clear evidence of de-differentiation of the duct cells during duct call proliferation so far. Herein we report the changes of intermediate filament protein expression in rapidly proliferating duct cells after partial pancreatectomy for the evidence of de-differentiation of the duct cells. METHODS: 45 week-old Sprague-Dawley rats weighing 80~120 g were used. 90% partial pancreatectomy was done. Experimental animals were divided into 5 subgroups by date of killing after surgery: 1, 3, 7, 14, 30 days, Pancreas remnant was excised and immunohistochemical stain was done for pancytokeratin (Pan-CK) as a epithelial cell marker and vimentin (VT) as a mesenchymal cell marker. We observed the double stained slide with pan-CK and VT antibody using confocal microscope for costaining analysis over time. The sections were also immunostained with anti-insulin antibody for the quantification of the beta cell mass by point-counting methods. RESULTS: We observed impaired glucose tolerance and diabetes were developed affer 90% pancreatectomy. Significant increase of the weight of pancreatic remnant, beta cell and duct cell mass were observed about 14 days after pancreatectomy. We observed the co-expression of VT and pan-CK intermediate filament protein in rapidly proliferating duct cells in the area of common pancreatic duct and main duct at one day after partial pancreatectomy. 3 days affer partial pancreatectomy, VT and pan-CK costained duct cells were mainly observed in the rageneration focus of the duct cell proliferation. 30 days after partial pancreatectomy, we could not find any costaining duct calls in the remnant pancreas. CONCLUSION: The vimentin intermediate filament, a marker of mesenchymal cell was expressed in proliferating ductal cells after pancreatectomy. We could suspect that pancytokeratin and vimentin co-expression is a good marker for de-differentiation of proliferating duct cells.
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