Glucose-dependent blood flow dynamics in murine pancreatic islets in vivo
Glucose-dependent blood flow dynamics in murine pancreatic islets in vivo
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DOI：
10.1152/ajpendo.00715.2009
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发表时间：
2010-04-01
影响因子：
5.1
通讯作者：
Piston, David W.
中科院分区：
文献类型：
--
作者：
Nyman, Lara R.;Ford, Eric;Piston, David W.
尼曼LR，福特E，电源交流，活塞DW。小鼠体内胰岛的葡萄糖依赖性血流动力学。Am J Physiol Endocrinol Metab 298：E807-E814，2010.首次发表于2010年1月13日; doi：10.1152/ajpendo.00715.2009。胰岛是高度血管化的，其排列方式使得含有β细胞的区域与含有其他细胞类型的区域不同。虽然胰岛血流已被广泛研究，但对低血糖或高血糖时胰岛血流的动力学知之甚少。为了研究胰岛血流量随血糖水平的变化，我们在高血糖（类似于300 mg/dl或16.8 mM）和低血糖（类似于50 mg/dl或2.8 mM）水平下依次钳制血糖，同时在β细胞中表达绿色荧光蛋白或α细胞中表达黄色荧光蛋白的小鼠模型中对胰岛内血流量进行成像。使用线扫描共聚焦显微镜，在体内血流测定后，静脉注射荧光葡聚糖或磺酰罗丹明标记的红细胞。无论低血糖和高血糖的顺序如何，高血糖期间胰岛血流更快，高血糖期间的表观血容量大于低血糖期间。但与高血糖相比，低血糖时不同类型的胰岛内分泌细胞的灌注顺序没有变化，通常首先灌注β细胞的胰岛核心。与胰岛的结果相反，高血糖和低血糖时胰腺外分泌部的流速无显著差异。这些结果表明，葡萄糖差异调节胰岛血管系统中的血流，而不依赖于胰腺其余部分中的血流。
Nyman LR, Ford E, Powers AC, Piston DW. Glucose-dependent blood flow dynamics in murine pancreatic islets in vivo. Am J Physiol Endocrinol Metab 298: E807-E814, 2010. First published January 13, 2010; doi:10.1152/ajpendo.00715.2009.-Pancreatic islets are highly vascularized and arranged so that regions containing beta-cells are distinct from those containing other cell types. Although islet blood flow has been studied extensively, little is known about the dynamics of islet blood flow during hypoglycemia or hyperglycemia. To investigate changes in islet blood flow as a function of blood glucose level, we clamped blood glucose sequentially at hyperglycemic (similar to 300 mg/dl or 16.8 mM) and hypoglycemic (similar to 50 mg/dl or 2.8 mM) levels while simultaneously imaging intraislet blood flow in mouse models that express green fluorescent protein in the beta-cells or yellow fluorescent protein in the alpha-cells. Using line scanning confocal microscopy, in vivo blood flow was assayed after intravenous injection of fluorescent dextran or sulforhodamine-labeled red blood cells. Regardless of the sequence of hypoglycemia and hyperglycemia, islet blood flow is faster during hyperglycemia, and apparent blood volume is greater during hyperglycemia than during hypoglycemia. However, there is no change in the order of perfusion of different islet endocrine cell types in hypoglycemia compared with hyperglycemia, with the islet core of beta-cells usually perfused first. In contrast to the results in islets, there was no significant difference in flow rate in the exocrine pancreas during hyperglycemia compared with hypoglycemia. These results indicate that glucose differentially regulates blood flow in the pancreatic islet vasculature independently of blood flow in the rest of the pancreas.