Diabetes & Metabolism Journal

Original Articles

Characterization of Preadipocyte factor-1 (Pref-1) Expressing Pancreatic Cells.: Marie Rhee, Sun Hee Suh, Youn Joo Yang, Ji Won Kim, Sung Yoon Jeon, Oak Kee Hong, Seung Hyun Ko, Yoon Hee Choi, Bong Yun Cha, Ho Yong Son, Kun Ho Yoon; Korean Diabetes J. 2005;29(6):507-516. Published online November 1, 2005

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Abstract PDF: BACKGROUND
Preadipocyte factor-1/Delta-like 1(Pref-1/Dlk1) is a type I membrane protein that has six epidermal growth factor (EGF)-like repeats in its extracellular and a short cytoplasmic domain. It is widely expressed in embryonic tissues, whereas its expressions were limited in adult and postnatal stage. To characterize the Pref-1 expressing cells during pancreas development and regeneration after birth, we analyzed Pref-1 expression in embryonic and adult partial pancreatectomized rat pancreas, and primary cultured neonatal pig pancreatic cells. METHODS: Whole fetuses or pieces of rat pancreas were obtained at E20. 90% partial pancreatectomy (Px) and sham operation were done using 5 week-old Sprague-Dawley rats. Experimental animals were divided into 11 groups by time of killing after surgery; 0, 1, 3, 6 and 12 hours, 1, 2, 3, 5, 7, and 14 days. All tissues were immunostained with Pref-1 and analysed by reverse transcriptase (RT)-PCR. Porcine neonatal pancreas cell clusters (NPCCs) were prepared from neonatal pigs aged 1-2 days. Cells were harvested on day 0, 3, 4, 5, 6, and 7 after dispersion. All cells were immunostained with Pref-1 and other specific cell markers such as Pan-cytokeratin (Pan-CK), vimentin (VT) and islet hormones, and confirmed by Western blot, RT-PCR and fluorescence activated cell sorting (FACS) analysis. RESULTS: In the rat embryonic pancreas at E20, Pref-1 expression was restricted only in the small branching ductules. In adult rat pancreas, Pref-1 was not expressed at all. Whereas, Pref-1 transiently expressed in the small regenerating duct cells located in foci of regeneration in Px model, then completely disappeared at day 7. The Pref-1 mRNA measured by RT-PCR was peaked at day 3 after Px and then gradually disappeared. Pref-1 expression pattern was also reproduced in monolayer cultured NPCCs. In NPCCs, protein levels of Pref-1 were peaked at day 0 to day 4 then gradually disappeared until day 7 by western blot. Most of Pref-1 expressing cells were co-stained with cytokeratin. The proportion of Pref-1 expressing cells in dispersed NPCCs were counted and isolated by FACS at 3 days after culture were 25% and then decreased over time during 7 days culture period. CONCLUSIONS: Pref-1 expression was regained in adult pancreatic cells during regeneration in vivo and in vitro and Pref-1 might be a useful marker for the pancreatic protodifferentiated cells.

In Vitro Expansion and Differentiation of Islet Precursor Cells from Cultured Neonatal Porcine Pancreatic Tissue.: 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; Korean Diabetes J. 2000;24(3):310-322. Published online January 1, 2001

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Abstract PDF: 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.: 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; Korean Diabetes J. 2000;24(2):191-201. Published online January 1, 2001

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Abstract PDF: BACKGROUND
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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