Monitoring contractile forces during airway constriction

项目概述：在所有已知的对抗健康肺支气管收缩的因素中，深呼吸 是最有效的方法之一然而，在哮喘肺中，这种保护现象基本上是在- 在自发性哮喘发作期间，它有时甚至被逆转。一些人建议 深呼吸无法扩张收缩的哮喘气道可能是哮喘发作的一个重要原因， 持续气道狭窄。为了解释这些观察结果，我们最近的发现引起了人们对以下问题的关注： 该呼吸实际上拉伸了气道壁，即施加的周向应变的大小。 周向应变又必须作为两个物理因素的函数而反向变化：（i）材料的刚度， 气道壁中的细胞和细胞外基质（ECM）的非收缩性成分，以及（ii）产生的力 气道平滑肌（ASM）。然而，直接测量这些几乎是不可能的。 因素及其在实质内人体气道环境中的相对作用。在没有 这些知识，管理机制将仍然很难阐明，关键的病理生理学的见解， 保持隐藏。例如，在哮喘中，增强的ECM硬度是否使气道对哮喘不敏感？ 深层灵感的有益效果？或者疾病的病理生理学是由异常的ASM con- 延展性？为了找到这些问题的答案，在这项基础拨款中，我们建议开发新的使能技术， 测量技术利用我们首创的生物力学方法，称为牵引力微- 在第一个目标中，我们建议测量由位于以下位置的ASM产生的收缩力- 在完整的人实质内气道中并进行模拟呼吸。我们在目标2中建议， 一种新技术，用于测量气道壁细胞外基质（ECM）成分的原位硬度 并将局部细胞外基质刚度与局部细胞外基质承受的应力关联起来。

Project summary: Among all factors known to antagonize bronchoconstriction in a healthy lung, a deep breath is among the most effective. In the asthmatic lung, however, this protective phenomenon is substantially at- tenuated and during a spontaneous asthmatic attack it is sometimes even reversed. Some have suggested that the inability of a deep breath to dilate the constricted asthmatic airway might be an important cause of ex- cessive airway narrowing. To explain these observations, our recent findings call attention to the extent to which breathing actually stretched the airway wall, i.e. the magnitude of circumferential strain that is imposed. The circumferential strain, in turn, must vary inversely as a function of two physical factors: (i) stiffness of the non-contractile elements of the cells and extracellular matrix (ECM) in the airway wall, and, (ii) force generated by the airway smooth muscle (ASM) itself. However, it has been nearly impossible to directly measure these factors and their relative contributions in the settings of the intraparenchymal human airway. In the absence of such knowledge, governing mechanisms will remain poorly elucidated and key pathophysiological insights will remain hidden. For example, in asthma, does enhanced ECM stiffness render the airway refractory to the beneficial effects of deep inspirations? Or is the disease pathophysiology dominated by aberrant ASM con- tractility? To find answers to these questions, in this foundational grant, we propose to develop novel enabling measurement technologies. Using a biomechanical approach that we have pioneered called traction force mi- croscopy (TFM), we propose in aim 1 to measure contractile forces generated by the ASM that is situated with- in intact human intraparenchymal airways and subjected to simulated breathing. We propose in aim 2 to de- velop new technology to measure in situ stiffness of extracellular matrix (ECM) components of the airway wall and to correlate local ECM stiffness with local cell-ECM borne stresses.