Relationship of airway remodeling with clinical characteristics in bronchial asthma / 천식및알레르기

ABSTRACT

BACKGROUND: We observed airway remodeling, which is the thickness of the susepithelial layer, in asthmatic patients and inhealthy subjects in order to determine its relationship with severity of disease, such as symptom, bronchial hyperresponsiveness, and degree of acute exacerbation. Moreover, for evaluation of factors contributing to airway remodeling, we analyzed the age, sex, presence of atopy, length of asthmatic history and degree of airway inflammation. METHODS: Thirty-six patients with asthma and ten healthy controls were recruited for the study. The degree of asthma symptom severity was assessed using NIH criteria. Bronchial responsiveness to methacholine was expressed as provocative concentration of methacholine causing a 20% fall in FEV1. The degree of acute exacerbation was assessed by PaCO2 during acute exacerbation. Bronchoscopy, bronchoalveolar lavage(BAL), and bronchial biopsy were performed for all subjects; the total cell counts, differential cell counts and levels of ECP were measured in BAL fluid, and the basement membrane thickness and degree of epithelial shedding were measured in biopsy samples under light microscopy. RESULTS: The mean values of basement membrane thickness were 7.8+/-0.6 micrometer in asthmatics, and 4.1+/-0.5 micrometer in healthy subjects (p or =7.5 micrometer) compared to those with base- ment membrane less than 7.5micrometer (0.26+/-0.13 mg/ml vs. 0.74+/-0.16 mg/ml, p<0.05). No difference was found between the degree of thickening in patients with different degree of acute exacerbation with age, sex, atopy and lengths of asthmatic history. The degree of thickening was positively correlated to degree of epithelial shedding (r=0.393, p<0.05), but not to the degree of total cell counts, differential cell percentage nor ECP in BAL fluid. CONCLUSION: We confirmed that thickening of the basement membrane is a characteristic finding of asthma. We also demonstrated that it affects symptom severity and bronchial hyperresponsiveness, and is related to degree of epithelial damage rather than duration of asthma history.