Does the pattern of ventilation distribution predict airway hyperresponsiveness?

当受到刺激时，呼吸道容易变窄的趋势被称为气道高反应性(AHR)。AHR是哮喘的一个重要特征，但它也发生在其他疾病中，如慢性阻塞性肺疾病(COPD)--一种由吸烟引起的呼吸道疾病，以及囊性纤维化。患有AHR的人有更严重的呼吸道疾病，无论他们患有哪种疾病，而且更有可能在老年发展为肺功能不佳，住院或死于他们的疾病。如果我们能了解AHR的原因，我们就能更好地理解为什么一些呼吸道疾病患者的预后不佳。我们最近发现，在哮喘中，AHR与肺内空气分布不均匀有非常密切的关系。我们认为，导致这种不均匀分布的呼吸道结构变化使呼吸道容易发生AHR。这增加了在其他呼吸系统疾病中导致呼吸不均匀的因素也可能使呼吸道易患AHR的可能性。如果这是真的，这表明AHR在一系列不同的疾病中只有一个生理基础，这将使我们能够更密切地研究通风不均匀的原因。在这个项目中，我们将测量哮喘、慢性阻塞性肺疾病或囊性纤维化患者的AHR与不均衡的通风之间的关系。这项研究很重要，因为老年哮喘患者，特别是那些呼吸道永久狭窄的人，他们的呼吸道结构变化可能比年轻哮喘患者更多，而慢性阻塞性肺病和囊性纤维化患者的结构变化和呼吸道炎症模式与哮喘患者不同。这项研究将告诉我们，AHR和不均匀的通风是否存在一致的关系。如果是这样的话，这将是导致通风不均匀的因素导致AHR的极其有力的证据，并将为新治疗方法的研究指明方向。

The tendency for airways to narrow too easily when stimulated is called airway hyperresponsiveness (AHR). AHR is an important feature of asthma, but it also occurs in other diseases, such as chronic obstructive pulmonary disease (COPD) - an airway disease caused by smoking, and cystic fibrosis. People who have AHR have more severe respiratory disease, regardless of which disease they have, and are more likely to develop poor lung function in old age and to be hospitalised or die from their disease. If we can understand the causes of AHR we will have a better understanding of why some people with respiratory disease have poor outcomes. We have recently discovered that, in asthma, there is a very close relationship between AHR and the uneven distribution of air within the lungs. We believe that structural changes in the airways that cause this uneven distribution make the airways prone to AHR. This raises the possibility that factors that cause uneven ventilation in other respiratory diseases might also predispose the airways to AHR. If this is true, it suggests that there is a single physiological basis for AHR in a range of different diseases, and would allow us to focus research more closely on the causes of uneven ventilation. In this project we will measure the relationship between AHR and uneven ventilation in people with asthma, COPD or cystic fibrosis. The study is important because older people with asthma, particularly those with permanently narrowed airways, are likely to have more structural changes in their airways than young asthmatics, whereas people with COPD and cystic fibrosis have a different pattern of both structural changes and airway inflammation from that in asthma. The study will tell us whether there is a consistent relationship between AHR and uneven ventilation. If so, this would be extremely strong evidence that the factors that cause uneven ventilation contribute to AHR, and will point the way to studies of new treatments.