The Dynamic Topography of the Blood-Contacting Surface of Arteries

当动脉段从身体中取出时，它们在内部具有明显的波纹状外观。 长期以来，人们一直认为这是动脉收缩的结果，因为血压的影响被消除了。 该项目的研究人员假设，皱纹实际上在正常的生理功能中发挥作用，并且由于动脉压和直径的正常变化而发生显着变化。 这一假设将通过实验和建模技术相结合进行研究。 研究人员将回答有关这些皱纹的基本生物力学以及它们如何随正常生理功能和身体内动脉结构的长度沿着变化的问题。 所获得的知识将显著影响对动脉生物力学及其生理功能的基本理解。 它还可能为未来开发用于治疗受伤或患病动脉的改进替代动脉移植物设计提供信息。 这项研究将由一个独特的研究团队进行，其中包括医疗居民以及研究生和本科生。 这将支持工程师将工程研究与实际生理学和潜在临床影响联系起来的能力。 此外，动脉力学和基础材料性能模块将作为一系列讲座演示活动的一部分开发，为K12学生提供科学的视觉理解。三个目标已经建立，以测试所述假设。 首先，研究小组将通过将内弹性膜（内表面）视为与软基底接触的薄的、几乎不可伸展的膜来研究管腔皱褶的生物力学。 其次，将研究动脉的动态地形图，以了解正常生理条件下的波纹状态。 最后，将研究动脉向心脏远端移动（远离心脏）时管腔结构和波纹的变化。 这项工作将使用成像和生物力学测试策略相结合，在体内和离体动脉从猪标本，和生物力学行为将与胶原和弹性蛋白的微观结构。 这些实验将与有限元模型合作，这些模型将用于了解生物力学行为的潜在机制，并且一旦验证，将调查无法通过实验轻松研究的不同载荷和边界条件。 如果基本假设成立，研究人员计划将他们的发现与次要假设联系起来，即皱褶的功能作用是通过允许动脉适应动脉直径的变化来保护动脉的内皮层，而不会影响动脉的正常功能。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响进行评估，被认为值得支持审查标准。

When segments of arteries are removed from the body, they have a distinct, corrugated appearance on the inside. It has long been assumed that this is a result of the artery deflating as the effect of blood pressure is removed. The investigators in this project hypothesize that the corrugations actually play a role in normal, physiological function and that they change significantly due to normal changes in arterial pressure and diameter. This hypothesis will be studied through a combination of experimental and modeling techniques. The researchers will answer questions about the underlying biomechanics of these corrugations as well as how they vary with normal physiological function and along the length of the arterial structure within the body. The knowledge gained will significantly impact fundamental understanding of arterial biomechanics and their physiological function. It may also inform future development of improved replacement arterial graft designs for treatment of injured or diseased arteries. The research will be conducted by a unique research team that includes medical residents as well as graduate and undergraduate students. This will support the engineers ability to connect the engineering research to the actual physiology and potential clinical impact. In addition, modules on arterial mechanics and the underlying materials performance will be developed as part of a series of lecture-demonstration activities that provide K12 students with a visual understanding of the science.Three aims have been established to test the stated hypothesis. First, the team will investigate the biomechanics of the luminal corrugations by treating the internal elastic lamina (the inner surface) as a thin, nearly-inextensible membrane in contact with a soft substrate. Second, the dynamic topography of the arteries will be investigated to understand the state of the corrugations under normal physiologic conditions. Finally, the variation in luminal structure and corrugations will be investigated for arteries as they move distal to (away from) the heart. This work will use a combination of imaging and biomechanical testing strategies in both in vivo and excised arteries from porcine specimens, and the biomechanical behavior will be related to the collagen and elastin microstructure. The experiments will be partnered with finite element models that will be used to understand the underlying mechanisms of the biomechanical behavior as well as, once validated, investigate varying loads and boundary conditions that cannot easily be studied experimentally. If the primary hypothesis is supported, the investigators plan to link their findings to the secondary hypothesis that the functional role of the corrugations is to protect the endothelial layer of the artery by allowing it to accommodate the arterial diameter changes without in-plane stretching.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.