Department of Respiratory Medicine, Kyoto University Graduate School of Medicine, Shogoin, Sakyoku, Kyoto 606-8507, Japan.
Chest. 2010 May;137(5):1122-9. doi: 10.1378/chest.09-0081. Epub 2010 Jan 15.
Mucus hypersecretion is an important pathophysiologic index of airway disease. Measurement of secreted mucin in sputum has been reported in asthma, but not in chronic cough with or without increased sputum production.
We studied 49 patients with classic asthma (CA), 39 with cough-variant asthma (CVA), nine and five with chronic cough associated with sinobronchial syndrome (SBS) and gastroesophageal reflux disease (GERD), respectively, and 11 healthy controls. Seventeen patients with CA, but none from the other groups, were taking antiinflammatory medications. Mucin levels in induced sputum supernatants were measured by enzyme-linked immunosorbent assay, which detects airway mucin, probably including MUC5AC and MUC5B.
Mucin levels were higher in patients with CA (674.2 +/- 548.8 microg/mL) and SBS (638.4 +/- 650.7 microg/mL) than in controls (212.0 +/- 167.1 microg/mL) (P = .0037 and .044). They were also higher in patients with CA than in those with CVA (350.4 +/- 374.0 microg/mL) and GERD (134.3 +/- 93.1 microg/mL) (P = .0016 and 0.015), but results did not differ between the latter groups and controls. When the four disease groups were combined, patients with frequent sputum production had greater mucin levels than those with occasional (P = .0023) or no sputum production (P < .0001). Patients with CA showed negative correlations of mucin levels with respiratory resistance indices on impulse oscillation and with airway sensitivity to methacholine.
Sputum mucin levels differ in various respiratory conditions when compared with controls, primarily reflecting the degree of sputum production. Airway mucin might possibly exert protective effects in asthma, at least between exacerbations, but this issue needs to be further clarified by future studies.
黏液高分泌是气道疾病的一个重要病理生理指标。在哮喘中已经报道了痰液中分泌的黏蛋白的测量，但在慢性咳嗽伴或不伴痰液增多的患者中尚未报道。
我们研究了 49 例典型哮喘（CA）患者、39 例咳嗽变异性哮喘（CVA）患者、9 例慢性咳嗽伴鼻支气管炎综合征（SBS）和 5 例胃食管反流病（GERD）患者以及 11 例健康对照者。17 例 CA 患者正在服用抗炎药物，但其他组没有。通过酶联免疫吸附试验（检测气道黏蛋白，可能包括 MUC5AC 和 MUC5B）测量诱导痰上清液中的黏蛋白水平。
CA 组（674.2±548.8μg/mL）和 SBS 组（638.4±650.7μg/mL）的黏蛋白水平高于对照组（212.0±167.1μg/mL）（P=0.0037 和 0.044）。CA 组的黏蛋白水平也高于 CVA 组（350.4±374.0μg/mL）和 GERD 组（134.3±93.1μg/mL）（P=0.0016 和 0.015），但后两组与对照组之间的差异无统计学意义。当将这四个疾病组合并时，频繁咳痰的患者的黏蛋白水平高于偶发（P=0.0023）或无痰的患者（P<0.0001）。CA 患者的黏蛋白水平与脉冲震荡呼吸阻力指数呈负相关，与气道对乙酰甲胆碱的敏感性呈负相关。
与对照组相比，各种呼吸道疾病的痰液黏蛋白水平不同，主要反映了痰液产生的程度。气道黏蛋白可能在哮喘中发挥保护作用，至少在哮喘加重之间，但这一问题需要进一步通过未来的研究来阐明。
