The role of shear stress and sympathetic nervous activity in the regulation of human arterial function and structure

剪切应力和交感神经活动在人体动脉功能和结构调节中的作用

• 批准号: 372292-2009
• 负责人: Pyke, Kyra
• 金额: $ 2.19万
• 依托单位: Queen's University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2013
• 资助国家: 加拿大
• 起止时间: 2013-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=528524
• 关键词: role; shear; stress; sympathetic; nervous

Our arteries are lined by a single layer of cells called the vascular endothelium. Due to their position on the inside of the artery, the endothelial cells are constantly exposed to the frictional force created by the flowing blood. Termed shear stress, this frictional force plays a key role in regulating endothelial cell responses that change artery size and stiffness in both the short and the long term. We are interested in understanding the sensitivity of the endothelium to changes in shear stress, the speed of its responses and how these factors may differ in arteries that are in the arms vs. the legs. We will use cutting edge Doppler ultrasound technology to measure both changes in shear stress and changes in artery size and stiffness. In daily living, the most common cause of increases in shear stress is performing exercise. Exercise also results in long term changes in artery function and structure, however, we do not know if these changes are brought about by increases in shear stress per se, or other variables that change with exercise. We will isolate the role of shear stress in changes in artery function with a novel technique that allows us to mimic exercise induced changes in shear stress without having to perform contractions. In addition to responding to changes in shear stress, our arteries are also controlled by nerves. Similar to the motor neurons that that stimulate our skeletal muscles to contract, the nerves that control our arteries cause the muscle in their walls to contract, making the vessel smaller. We still do not clearly understand the ways in which responses to increases in shear stress, and responses to signals from the nerves interact when they are experienced simultaneously in the same artery. In experiments we will manipulate both variables, and measure changes in artery size and factors in the blood that reflect neural and endothelial cell function. This will give us important insight into the complex interaction and integration of signals in our arteries. The information gained from these studies will assist in advancing our understanding of basic human cardiovascular function.

我们的动脉由一层叫做血管内皮的细胞构成。由于它们位于动脉内部，内皮细胞经常受到血流产生的摩擦力的影响。这种摩擦力被称为剪切应力，在调节内皮细胞的反应中起着关键作用，在短期和长期内改变动脉的大小和刚度。我们感兴趣的是了解内皮对剪切应力变化的敏感性，其反应速度以及这些因素在手臂动脉和腿部动脉中的差异。我们将使用最先进的多普勒超声技术来测量剪切应力的变化以及动脉大小和刚度的变化。在日常生活中，导致剪应力增加的最常见原因是运动。运动也会导致动脉功能和结构的长期变化，然而，我们不知道这些变化是由剪应力本身的增加带来的，还是由于运动而改变的其他变量。我们将分离剪切应力在动脉功能变化中的作用，采用一种新技术，使我们能够模拟运动引起的剪切应力变化，而无需进行收缩。除了对剪应力的变化作出反应外，我们的动脉还受神经的控制。与刺激骨骼肌收缩的运动神经元类似，控制动脉的神经会使动脉壁的肌肉收缩，使血管变小。我们仍然不清楚，在同一动脉中，对剪应力增加的反应和对神经信号的反应是如何相互作用的。在实验中，我们将操纵这两个变量，并测量动脉大小和血液中反映神经和内皮细胞功能的因素的变化。这将使我们对动脉中信号的复杂相互作用和整合有重要的了解。从这些研究中获得的信息将有助于提高我们对人类基本心血管功能的理解。