Ijpma Gijs, Matusovsky Oleg, Lauzon Anne-Marie
Meakins-Christie Laboratories, McGill University, 3626 St. Urbain Street, Montreal, QC, Canada H2X 2P2 ; Department of Medicine, McGill University, 687 Pine Avenue, Montreal, QC, Canada H3A 1A1.
J Allergy (Cairo). 2012;2012:156909. doi: 10.1155/2012/156909. Epub 2012 Dec 25.
It remains unclear whether airway smooth muscle (ASM) mechanics is altered in asthma. While efforts have originally focussed on contractile force, some evidence points to an increased velocity of shortening. A greater rate of airway renarrowing after a deep inspiration has been reported in asthmatics compared to controls, which could result from a shortening velocity increase. In addition, we have recently shown in rats that increased shortening velocity correlates with increased muscle shortening, without increasing muscle force. Nonetheless, establishing whether or not asthmatic ASM shortens faster than that of normal subjects remains problematic. Endobronchial biopsies provide excellent tissue samples because the patients are well characterized, but the size of the samples allows only cell level experiments. Whole human lungs from transplant programs suffer primarily from poor patient characterization, leading to high variability. ASM from several animal models of asthma has shown increased shortening velocity, but it is unclear whether this is representative of human asthma. Several candidates have been suggested as responsible for increased shortening velocity in asthma, such as alterations in contractile protein expression or changes in the contractile apparatus structure. There is no doubt that more remains to be learned about the role of shortening velocity in asthma.
气道平滑肌（ASM）力学在哮喘中是否发生改变仍不清楚。虽然最初的研究重点是收缩力，但一些证据表明缩短速度有所增加。与对照组相比，哮喘患者在深吸气后气道再狭窄的速度更快，这可能是由于缩短速度增加所致。此外，我们最近在大鼠中发现，缩短速度增加与肌肉缩短增加相关，而不增加肌肉力量。然而，确定哮喘患者的ASM是否比正常受试者缩短得更快仍然存在问题。支气管活检可提供优质的组织样本，因为患者特征明确，但样本大小仅允许进行细胞水平的实验。移植项目中的整个人肺主要存在患者特征描述不佳的问题，导致变异性很大。来自几种哮喘动物模型的ASM显示缩短速度增加，但尚不清楚这是否代表人类哮喘。有人提出了几种可能导致哮喘中缩短速度增加的因素，如收缩蛋白表达的改变或收缩装置结构的变化。毫无疑问，关于缩短速度在哮喘中的作用仍有更多需要了解的地方。
