Alonso Laura C, Yokoe Takuya, Zhang Pili, Scott Donald K, Kim Seung K, O'Donnell Christopher P, Garcia-Ocaña Adolfo
University of Pittsburgh, Division of Endocrinology, 200 Lothrop St., BST E1140, Pittsburgh, PA 15261, USA.
Diabetes. 2007 Jul;56(7):1792-801. doi: 10.2337/db06-1513. Epub 2007 Mar 30.
Developing new techniques to induce beta-cells to replicate is a major goal in diabetes research. Endogenous beta-cells replicate in response to metabolic changes, such as obesity and pregnancy, which increase insulin requirement. Mouse genetic models promise to reveal the pathways responsible for compensatory beta-cell replication. However, no simple, short-term, physiological replication stimulus exists to test mouse models for compensatory replication. Here, we present a new tool to induce beta-cell replication in living mice. Four-day glucose infusion is well tolerated by mice as measured by hemodynamics, body weight, organ weight, food intake, and corticosterone level. Mild sustained hyperglycemia and hyperinsulinemia induce a robust and significant fivefold increase in beta-cell replication. Glucose-induced beta-cell replication is dose and time dependent. Beta-cell mass, islet number, beta-cell size, and beta-cell death are not altered by glucose infusion over this time frame. Glucose infusion increases both the total protein abundance and nuclear localization of cyclin D2 in islets, which has not been previously reported. Thus, we have developed a new model to study the regulation of compensatory beta-cell replication, and we describe important novel characteristics of mouse beta-cell responses to glucose in the living pancreas.
开发诱导β细胞复制的新技术是糖尿病研究的一个主要目标。内源性β细胞会对代谢变化(如肥胖和怀孕)作出反应而进行复制,这些代谢变化会增加胰岛素需求。小鼠遗传模型有望揭示负责代偿性β细胞复制的途径。然而,目前尚无简单、短期的生理性复制刺激来测试小鼠模型的代偿性复制。在此,我们提出一种在活体小鼠中诱导β细胞复制的新工具。通过血流动力学、体重、器官重量、食物摄入量和皮质酮水平测量发现,小鼠对为期四天的葡萄糖输注耐受性良好。轻度持续性高血糖和高胰岛素血症可使β细胞复制显著强劲增加五倍。葡萄糖诱导的β细胞复制具有剂量和时间依赖性。在此时间范围内,葡萄糖输注不会改变β细胞质量、胰岛数量、β细胞大小和β细胞死亡情况。葡萄糖输注会增加胰岛中细胞周期蛋白D2的总蛋白丰度和核定位,这一点此前未见报道。因此,我们开发了一种新模型来研究代偿性β细胞复制的调控,并描述了活体胰腺中小鼠β细胞对葡萄糖反应的重要新特征。