Exploration into the role of progesteron reseptor in islet beta cells of Japanese type 2 diabetic subjects

我们研究了115名非糖尿病日本受试者的β细胞体积密度随年龄和身体状况（即肥胖）的动力学。20多岁后β细胞体积的显著下降与年龄和身体状况无关。这表明日本人的β细胞对各种情况的适应能力低于西方受试者。此外，对衰老或2型糖尿病诱导的β细胞中P16和孕激素受体基因的DNA高甲基化的评估显示没有高甲基化。然而，一小部分受试者表现出P16基因的DNA高甲基化，与衰老或2型糖尿病无关。这些受试者还表现出β细胞的高增殖率（bbb2%）。总的来说，年龄和身体状况对日本受试者的β细胞体积没有影响。P16基因的DNA高甲基化可能与β细胞的增殖有关，与糖尿病状态或衰老无关。

We investigated the kinetics of volume density of beta cells by aging and physical status (i.e. obesity) in 115 non-diabetic Japanese subjects. Significant decline of beta cell volume after twenties was identified by neither aging nor physical status. This result indicated that Japanese beta cell had less ability to adapt to various situation than that of western subjects.Furthermore, evaluation of DNA hypermethylation of P16 and progesteron receptor genes in beta cells induced by either aging or type 2 diabetes revealed no hypermetylation. However, small part of the examined subjects exhibited DNA hypermethylation in P16 gene independent of aging or type 2 diabetes. Those subjects also exhibited high proliferation rates of beta cells (>2%). Taken together, aging and physical status do not affect beta cell volume in the case of Japanese subjects. DNA hypermethylation of P16 gene is possibly associated with cell proliferation of beta cells irrespective of diabetic state or aging.