气道壁平滑肌增厚是哮喘的重要病理特征之一，为了阐明哮喘严重度与气道平滑肌之间的相关性，James进行了以下研究。
研究对象包括致死性哮喘患者(n = 107)、非致死性哮喘患者(n = 37)以及对照者(n = 69)。尸解后取大气道、中等气道和小气道组织做横切面切片，测量基底膜(PBM)和平滑肌层（ASMarea）厚度，使用多变量线性回归分析比较不同组的平滑肌厚度(ASMarea/PBM)。
研究结果：哮喘组ASMarea/PBM较对照组(0.036; 0.024–0.042)明显增加，其中非致死哮喘组ASMarea/PBM为0.04（0.013–0.051; p = 0.034)，而致死哮喘组ASMarea/PBM为0.048（0.025–0.078; p<0.001)。与非致死哮喘组相比，致死组哮喘患者大气道和中等气道的ASMarea/PBM均显著增加(p<0.001)，但二者的小气道ASMarea/PBM相比无明显差异。相关性分析发现，ASMarea/PBM与哮喘病程、发病年龄、性别以及吸烟史无关。
根据以上研究结果，作者认为，气道平滑肌厚度与哮喘严重度有关，但与哮喘病程无关。
（韩伟 青岛大学附属青岛市立医院东院 266071 摘译）
（Eur Respir J 2009; 34:1040-1045）
Airway smooth muscle thickness in asthma is related to severity but not duration of asthma
A. L. James, T. R. Bai, T. Mauad, M. J. Abramson, M. Dolhnikoff, K. O. McKay, P. S. Maxwell, J. G. Elliot and F. H. Green
Asthma is characterised by an increased airway smooth muscle (ASM) area (ASMarea) within the airway wall. The present study examined the relationship of factors including severity and duration of asthma to ASMarea.
The perimeter of the basement membrane and were measured on transverse sections of large and small airways from post mortem cases of fatal and nonfatal asthma and from control subjects. The thickness of ASM (ASMarea/PBM) was compared between asthma groups using multivariate linear regression.
When all airways were considered together, ASMarea/PBM (in millimetres) was increased in nonfatal (median 0.04; interquartile range 0.013–0.051; p = 0.034) and fatal cases of asthma (0.048; 0.025–0.078; p<0.001) compared with controls (0.036; 0.024–0.042). Compared with cases of nonfatal asthma, ASMarea/PBM was greater in cases of fatal asthma in large (p<0.001) and medium (p<0.001), but not small, airways. ASMarea/PBM was not related to duration of asthma, age of onset of asthma, sex or smoking. No effect due to study centre, other than that due to sampling strategy, was found.
The thickness of the ASM layer is increased in asthma and is related to the severity of asthma but not its duration.
