Diabetes & Metabolism Journal

Original Article

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

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Abstract 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.

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