Skip Navigation
Skip to contents

Diabetes Metab J : Diabetes & Metabolism Journal

Search
OPEN ACCESS

Author index

Page Path
HOME > Browse > Author index
Search
Yoo Bae Ahn  (Ahn YB) 5 Articles
Development of Adult Porcine Islet Isolation Method for Xenotransplantation.
Sung Rae Kim, Kun Ho Yoon, Hyuk Sang Kwon, Sun Hee Suh, Seung Hyun Ko, Jung Min Lee, Soon Jib Yoo, Yoo Bae Ahn, Ki Ho Song, Hyun Shik Son, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
Korean Diabetes J. 2004;28(2):75-87.   Published online April 1, 2004
  • 1,086 View
  • 24 Download
AbstractAbstract PDF
BACKGROUND
AND PURPOSE: Xenotransplantation using porcine islet cells might be an alternative to allotransplantation, which has been limited due to the lack of donors. Various researches using porcine islet cells have been performed in foreign countries; however, they have never been studies in Korea. Therefore, the purpose of this study was to explore the possibility of thise new treatment for cases of diabetes by establishing of improved islet isolation skill. METHODS: The pancreas and islets were extracted from pigs weighing around 100kg. To establish an islet isolation method, the islet yield, purity and the distribution size of the isolated islets were step wise compared in various ways, and then the superior method adopted. To determine the conveyance method after organ extraction, the conveyance method of pouring collagenase P was compared with the conveyance method of injecting Custidol. For digestion, the mechanical shaking and static incubation methods were also compared. To isolate islets from the digested pancreata, isolation methods were analyzed using 3 and 4 layers' Ficoll. The islet yield was appraised after their isolation using the optimized islet isolation method. To assess the results of the islet isolation, appraised the purity and the survival rates of cells, the insulin secretion resulting from the glucose stimulation test was examined. RESULTS: The method of injecting 4degrees C Custidol was effective for the conveyance and storage of the isolated pancreas in comparison with an injection of collagenase P(3465+/-1488 IEQ/g pancreas vs. 48+/-1.7 IEQ/g pancreas, p<0.01). The digestion method was superior to the mechanical shaking method at keeping a stable condition(3465+/-1488 IEQ/g pancreas vs. 1265+/-141.4 IEQ/g pancreas, p<0.01). Ficoll isolation using 3 layers gave the same results as using 4 layers. The average weights of the isolate Pancreatic islets was 23.8+/-3.3g. The numbers of islets per gram was 3465+/-1488.2(IEQ), with a the purity of 86.3+/-2.0%, and a survival rate of over 95%. The insulin secretion caused by glucose stimulation substantially increased in concentration from 24 to 72 hours(24hr: 5mM 3.12mU/mL --< 20mM 6.79mU/mL(2.17 fold), 72hr: 5mM 2.38mU/mL --< 9.93mU/mL(4.17fold))
Selective beta-Cell Loss and alpha-Cell Expansion in Islets of Type 2 Diabetic Patients.
Jae Hyoung Cho, In Kyu Lee, Kun Ho Yoon, Seung Hyun Ko, Sun Hee Suh, Jung Min Lee, Sung Rae Kim, Yoo Bae Ahn, Jong Min Lee, Hyun Shik Son, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
Korean Diabetes J. 2001;25(2):164-177.   Published online April 1, 2001
  • 1,276 View
  • 25 Download
AbstractAbstract PDF
BACKGROUND
It has been reported that a decrease in the beta-cell mass, may play a major role in the development of type 2 diabetes. Some stimuli that cause beta-cell loss can stimulate neogenesis from precursors as well as replication of matured beta-cells. In an animal-based studies reported that alpha-cells can also be produced in the course of alpha-cell neogenesis, after being treated with streptozotocin. Through this research, we attempted to determine the change of beta-cell mass according to the changes in alpha-cell mass and to characterize the size of the beta-cell nucleus observed in type 2 diabetes. METHOD: To estimate the relative fraction of alpha- and beta-cell mass in the pancreas, we counted beta-cells and alpha-cells by point count method. We also performed a double immunohistochemical staining with glucagon and insulin antibodies to calculate the ratio between these two cells area in the pancreas (A/B ratio). In order to measure the size of the beta-cell nucleus, an immunofluorescence staining of the nucleus and insulin was carried out. Data were gathered from type 2 diabetic subjects (n=19) and normal controls (n=8). RESULTS: Although there was no statistical difference, we observed the tendency of decrease of beta-cell mass and increase of alpha-cell mass in the pancreas of type 2 diabetic patients. The ratio of alpha-to beta-cell area in islet (A/B ratio) increased to 0.81+/-0.76 in diabetic patients compared to control with 0.26+/-0.25 (p<0.01). The mean of the A/B ratios of the islets more than 22,000 micro m2 was 1.64+/-1.10, whereas that of the islets less than 22,000 micro m2 was 0.73+/-0.67 in type 2 diabetic patients (p<0.01). The size of the beta-cell nucleus in both diabetic subjects and normal controls was bigger than that of exocrine cells (p<0.05) and 2.9% of beta-cells in type 2 diabetic subjects showed substantially enlarged nuclei more than M+5SD (M and SD means the average and standard deviation of nucleus size of exocrine cells, respectively) whereas this type of nucleus was found in only 0.5% of beta-cells in normal controls (p<0.05). CONCLUSION: The islet pathology in type 2 diabetes could be characterized by an expansion of alpha-cells associated with the selective loss of beta-cells. Some beta-cells found in diabetes showed a significant increase in size of the nucleus. Through the results from this study, we postulate that enlarged beta-cell nucleus and reverse of A/B ratio in the islets could be a marker of early senescence of beta-cells in patients with type 2 diabetes mellitus.
Effects of Cilostazol on Insulin Resistance in OLETF Rats.
Sung Rae Kim, Ki Hyun Baek, Seung Hyun Ko, Jung Min Lee, Sang Ah Chang, Yoo Bae Ahn, Soon Jib Yoo, Jong Min Lee, Hyun Shik Son, Kun Ho Yoon, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
Korean Diabetes J. 2001;25(1):63-70.   Published online February 1, 2001
  • 1,212 View
  • 18 Download
AbstractAbstract PDF
BACKGROUND
Insulin resistance is one of the major pathophysiology of type 2 diabetes mellitus. It is reported that cilostazol and cyclic AMP phosphodiesterase inhibitor has the anti-platelet effect as well as an improvement of hypertriglyceridemia in addition to vasodilatation. Furthermore, the previous reports indicated that there is a positive relationship between insulin resistance and dyslipidemia. Thus, we investigated the effects of cilostazol on insulin resistance in OLETF rats using the euglycemic hyperinsulinemic glucose clamp technique, and lipid levels. METHODS: Fifteen five months old OLETF rats were fed for 4 weeks(8 treated with cilostazol and 7 were control), and compare to 20 same aged LETO rats (8 treated with cilostazol and 12 were control) through the glucose infusion rate on euglycemic hyperinsulinemic glucose clamp and lipid profiles. RESULTS: The glucose infusion rate was higher in the cilostazol treated OLETF rats than in the non-cilostazol treated OLETF rats (0.021+/-0.0031 vs 0.027+/-0.0036 mL/min). The levels of free fatty acids (2424.8+/-652.7 vs 1061.8+/-223.2 Eq/L), total cholesterol (145.7+/-17.9 vs 115.4+/-7.6 mg/dL) and triglyceride (146.5+/-46.6 vs 76.1+/-12.5 mg/dL) of cilostazol treated OLETF rats were significantly lower than those of non-cilostazol treated OLETF rats. CONCLUSION: This study result suggest that cilostazol may improve the insulin resistance through the improvement of dyslipidemia in OLETF rats.
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
  • 1,030 View
  • 16 Download
AbstractAbstract 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.
Methylenetetrahydrofolate Reductase Polymorphism in Korean Type 2 Diabetic Patients with Macroangiopathy.
Ki Won Oh, Won Young Lee, Yoo Bae Ahn, Ki Ho Song, Soon Jib Yoo, Kun Ho Yoon, Moo Il Kang, Bong Yun Cha, Kwang Woo Lee, Ho Young Son, Sung Koo Kang
Korean Diabetes J. 1999;23(5):625-634.   Published online January 1, 2001
  • 860 View
  • 16 Download
AbstractAbstract PDF
BACKGROUND
Hyperhomocysteinemia is an inde-pendent risk factor for cardiovascular disease. Recently, a mutation (677CT) was identified in the methylenetetrahydrofolate reductase (MTHFR) gene, leading to the substitution of valine (V) for alanine (A). This mutation causes a reduced folate-dependent enzyme activity which leads to increased homocysteine. In this study, we examined the association between the V allele of the methylenetetrahydrofolate reductase gene and macroangiopathy in Korean patients with type 2 diabetes mellitus. METHODS: In 54 type 2 diabetic patients with macroangiopathy and 198 normal subjects, the MTHFR genotypes were analyzed by polymerase chain reaction (PCR), followed by Hinfl digestion. To confirm the detection of the MTHFR polymorphism by the PCR-restriction fragment length polymorphism (RFLP) analysis, DNA Sequencing was performed on the PCR products. RESULT: The allele frequency of the V mutation was slightly higher in the patients than in the normal subjects, but that was statistically not significant. The crude ORs and 95% CIs for the allele frequency of the V mutation were 1.16 (0.76~1.79). Genotype frequencies were 35.9% for AA, 48.4% for AV, and 15.7% for VV in the normal subjects. And they were 31.5% for AA, 50.0 % for AU, and 18.5 % for VV in the patients. The crude ORs and 95% CIs for the VV genotype were 1.22 (0.56~2.67). In multiple regressian model, the VV genotype was not associated with diabetic macroangiopathy. CONCLUSION: Although, the frequencies of VV genotype in Korean normals (=16%) are higher than those of other thical populations (=12%), this mutation is not associated with macroangiopathy in type 2 diabetic patients. But, our sample size was too small and larger cohort studies will be needed to confirm the effect of MTHFR polymorphism on the development of macroangiopathy in diabetic patients.

Diabetes Metab J : Diabetes & Metabolism Journal