Bronchial Biopsies in Asthma: An Ultrastructural, Quantitative Study and Correlation with Hyperreactivity

Abstract

Little is known of the structural changes in mild asthma. We have studied the light and electron microscopic structure of lobar bronchial biopsies taken at fiberoptic bronchoscopy from 11 atopic asthmatics, four of whom were symptomatic and seven of whom were asymptomatic. The former and three of the latter had bronchial hyperresponsiveness to methacholine (PC20 less than 4 mg/ml). Quantitative comparisons were made with biopsies from ten control subjects with normal airway reactivity; five had hay fever and five were nonatopic healthy volunteers. Complete absence of surface epithelium was found in three cases of symptomatic asthma, and stratified squamous epithelium was present in the fourth. A biopsy from one of the healthy control subjects had also lost its surface epithelium. The degree of epithelial loss in all subjects correlated with the degree of airway reactivity (rs = 0.67, p less than 0.001). The reticular lamina of the epithelial basement membrane showed a trend toward thickening in the seven hyperreactive asthmatics (p less than 0.001: median test). There was a tendency to high numbers of inflammatory cells in the lamina propria, but not in the submucosa, of asthmatics, but the differences between groups did not achieve statistical significance. There were significant alterations (px2 less than 0.001) in the proportions of each type of inflammatory cell found in the lamina propria and submucosa of symptomatic asthmatics: an increase of irregularly shaped lymphocytes contributed most to the observed alteration. Where surface epithelium was present, intraepithelial lymphocytes formed the major proportion of intraepithelial "migratory" cells: 64% in normal control subjects, 78% in subjects with hay fever, and 87% in asymptomatic asthmatics.(ABSTRACT TRUNCATED AT 250 WORDS)

Cartilaginous airway wall dimensions and airway resistance in cystic fibrosis lungs

“…The extensive loss of respiratory epithelium found in CF in the present study could, therefore, increase smooth muscle tone and thus increase airway obstruction and enhance bronchial responsiveness to histamine and methacholine [41]. In asthma, it has been shown that the greater the loss of respiratory epithelium in biopsy specimens the greater the degree of airway responsiveness [42]. Loss of cartilage is likely to make airways more collapsible and might therefore contribute to airflow limitation in CF.…”

Novel uses for anti‐platelet agents as anti‐inflammatory drugs

“…In addition, platelets are localized to various tissue compartments in the lung parenchyma of biopsies taken from asthmatic patients (Metzger et al, 1987;Jeffery et al, 1989) and this event is accompanied with bone marrow karyopoiesis and thrombopoiesis (Slater et al, 1985). This is perhaps the result of localized platelet recruitment and activation within lungs, since circulating venous platelet numbers have been shown to fall during both early-and late-phase responses to allergen (Kowal et al, 2006).…”

Remodelamento das vias aéreas inferiores e superiores

“…2,8 These proteins are produced by activated myofibroblasts, which leads to subepithelial fibrosis. 2,9 Thickening of the basement membrane was not related to the severity, duration or etiology of asthma in some studies; 10 others, however, have reported a correlation between these findings and disease severity. 11…”