Department of Mathematics, University of Auckland, New Zealand; Auckland Bioengineering Institute, University of Auckland, New Zealand.
Department of Mathematics, University of Auckland, New Zealand.
Respir Physiol Neurobiol. 2020 Jan;271:103257. doi: 10.1016/j.resp.2019.103257. Epub 2019 Sep 19.
Deep inspirations are a widely studied topic due to their varied effectiveness as a bronchodilator in asthmatic and non-asthmatic patients. Specifically, they are known to be effective at reversing bronchoconstriction in non-asthmatic patients but may fail to prevent bronchoconstriction in asthmatic patients. Inspired by a recent study on the effect of deep inspirations on the rate of re-narrowing of an isolated airway, we investigate whether the latch-bridge dynamics of smooth muscle cross-bridge theory, coupled with non-linear compliance of the airway wall, can account for the reported results: namely that only the rate of renarrowing after DI is sensitive to the interval between deep inspirations, while other measures are unaffected. We develop and present length- and pressure-controlled protocols which mimic both the experiments performed in the study, as well as simulate in vivo conditions respectively. Both protocols are simulated and show qualitative agreement with the results reported by the experiments, suggesting that latch-bridge dynamics coupled with airway wall non-compliance may be sufficient to explain these results. Moreover pressure- and length-controlled protocols show important differences which should be considered when designing in vitro experiments to mimic in vivo conditions.
深呼吸是一个广泛研究的课题，因为它们作为支气管扩张剂在哮喘和非哮喘患者中的效果不同。具体来说，已知它们在非哮喘患者中能有效地逆转支气管收缩，但可能无法预防哮喘患者的支气管收缩。受最近一项关于深呼吸对孤立气道再狭窄速度影响的研究的启发，我们研究了平滑肌交联桥理论的闩锁桥动力学，加上气道壁的非线性顺应性，是否可以解释报告的结果：即只有 DI 后再狭窄的速度对深呼吸之间的间隔敏感，而其他措施不受影响。我们开发并提出了长度和压力控制方案，分别模拟研究中进行的实验以及模拟体内条件。这两个方案都进行了模拟，并与实验报告的结果定性一致，表明闩锁桥动力学与气道壁顺应性的结合可能足以解释这些结果。此外，压力和长度控制方案显示出在设计体外实验以模拟体内条件时应考虑的重要差异。
