Department of Translational Research and New Technologies in Medicine and Surgery, University of Pisa, Pisa, Italy.
Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy.
Diabetes Metab Res Rev. 2017 Sep;33(6). doi: 10.1002/dmrr.2894. Epub 2017 Apr 18.
Both types of diabetes are characterized by beta-cell failure and death, leading to insulin insufficiency. Very limited information is currently available about the ultrastructural alterations of beta cells in human diabetes. Our aim was to provide a comprehensive ultrastructural analysis of human pancreatic islets in type 1 (T1D) and type 2 (T2D) diabetic patients.
We performed a morphometric electron microscopy evaluation of beta cells obtained from the pancreas of 8 nondiabetic (ND), 5 T1D, and 8 T2D organ donors.
A lower amount of beta cells was found in both T1D and T2D than in ND islets, whereas alpha cells were increased only in T2D. An increased number of bi-hormonal cells (showing both insulin and glucagon granules in their cytoplasm) were found in T1D. Insulin granules were less represented in T2D than in ND beta cells, whereas no significant changes were found in T1D. Volume density of the endoplasmic reticulum was increased in T2D and unchanged in T1D; mitochondria number and volume were significantly higher in T2D than in ND beta cells, whereas no significant differences were found in T1D. In both T1D and T2D, more beta cells showed signs of apoptosis than in ND.
Our results show that in each type of diabetes, beta cells exhibit specific ultrastructural alterations, whose better understanding might improve therapeutic strategies.
1 型（T1D）和 2 型（T2D）糖尿病的特征均为β细胞衰竭和死亡，导致胰岛素不足。目前关于人类糖尿病中β细胞的超微结构改变的信息非常有限。我们的目的是对 1 型和 2 型糖尿病患者的人胰腺胰岛进行全面的超微结构分析。
我们对 8 名非糖尿病（ND）、5 名 T1D 和 8 名 T2D 器官捐献者的胰腺β细胞进行了形态计量电子显微镜评估。
T1D 和 T2D 的β细胞数量均低于 ND 胰岛，而α细胞仅在 T2D 中增加。在 T1D 中发现了更多的双激素细胞（其细胞质中同时显示胰岛素和胰高血糖素颗粒）。与 ND 相比，T2D 中的胰岛素颗粒较少，而 T1D 中则没有明显变化。T2D 中的内质网体积密度增加，而 T1D 则不变；T2D 中的线粒体数量和体积明显高于 ND 中的β细胞，而 T1D 中则没有明显差异。在 T1D 和 T2D 中，与 ND 相比，更多的β细胞显示出凋亡迹象。
我们的研究结果表明，在每种类型的糖尿病中，β细胞均表现出特定的超微结构改变，更好地理解这些改变可能会改善治疗策略。
