Relationship between vascularity and other remodeling parameters in asthmatic airway

Background: The pathological features in asthmatic airway remodeling are diverse. The aim of this study was to examine the degree of airway vascularity in relation to the other remodeling parameters in asthmatics. Methods: Bronchial biopsies were done in 34 asthmatic patients, and 6 control subjects. The basement membrane thickness and the subepithelial thickness were measured in the hematoxylin-eosin stained tissue, and the degree of vascularity was measured using type IV collagen immunostaining. Results: 1) Compared to the control subjects, the asthmatics showed a significant increase in the basement membrane thickness (6.92±2.01 μm vs 9.67±2.84 μm, p<0.05) and the subepithelial thickness (44.49 ±31.92 μm vs 121.22±72.79 μm, p<0.05). 2) Compared to the control subjects, the asthmatics showed a significant increase in the vascular area per unit submucosal area (4.51±2.13% vs 10.32±6.08%, p<0.05). In addition, the number of vessels per unit submucosal area showed an increased tendency without statistical significance. 3) In the asthmatics, the number of vessels and the vascular area per unit submucosal area showed no correlation with the basement membrane thickness, the subepithelial thickness, the severity, the forced expiratory volume in 1 second(FEV₁), and the methacholine provocative concentration 20(PC₂₀). Conclusion: This study showed that vascularity was an important parameter in asthmatic airway remodeling but it was not related to the other remodeling parameters such as the basement membrane thickness and the subepithelial thickness. Each of these asthmatic remodeling parameters may have a different clinical significance. Therefore, further studies will be needed.