TGF-β Signaling Pathways in Different Compartments of the Lower Airways of Patients With Stable COPD

Background: The expression and localization of transforming growth factor-β (TGF-β) pathway proteins in different compartments of the lower airways of patients with stable COPD is unclear. We aimed to determine TGF-β pathway protein expression in patients with stable COPD. Methods: The expression and localization of TGF-β pathway components was measured in the bronchial mucosa and peripheral lungs of patients with stable COPD (n = 44), control smokers with normal lung function (n = 24), and control nonsmoking subjects (n = 11) using immunohistochemical analysis. Results: TGF-β1, TGF-β3, and connective tissue growth factor expression were significantly decreased in the bronchiolar epithelium…