Histological evaluation of bronchial tissue from elderly individuals with bronchial asthma

Abstract

We studied morphologic and morphometric characteristics of the bronchial walls in lungs obtained at autopsy form elderly patients who had had bronchial asthma. Thirteen patients (age at time of death 57 to 98 years; average, 81 years) were divided into three groups: AS, died of severe asthma attack (n = 4); AC, admitted with asthma symptoms but died of other diseases (n = 6); and NA, died of other diseases and had had no asthma symptoms in the year before death (n = 3). Lungs from ten non-smokers with no history of bronchial asthma or other lung disorders were used as control. Transverse sections of segmental and subsegmental bronchi were prepared, and four quantities were analyzed: 1) the ratio of total bronchial gland area to total area of the bronchial wall (Yamanaka index), 2) the thickness of the basement membrane, 3) the thickness of the smooth muscle bundle, and 4) the ratio of luminal area to total area of the bronchial wall (bronchial dilation ratio). In the AS group, the Yamanaka index and the thickness of the smooth muscle bundles and of the basement membrane were significantly greater than those in the control group at both the segmental and subsegmental levels, with massive eosinophil infiltration into the bronchial walls. Furthermore the bronchial dilation ratio at the subsegmental level correlated closely with the Yamanaka index. Thickness of the smooth muscle bundle seemed to be most representative of the severity of asthma symptoms. In conclusion, morphometric findings of bronchial walls in elderly patients with asthma symptoms seem to be similar to those in their younger counterparts.