Impact of Airway Mucus Plugs on Secondary Pulmonary Fibrosis in COPD Patients: A Single-Center Case-Control Study

Chronic obstructive pulmonary disease (COPD) is frequently accompanied by airway mucus plugs, which are closely associated with airflow obstruction, acute exacerbations, and increased mortality. However, whether mucus plugs contribute to secondary pulmonary fibrosis remains unclear. This single-center, prospective, case-control study aims to investigate the relationship between airway mucus plugs and lung fibrosis in patients with COPD undergoing lung cancer surgery. During surgery, distal non-tumorous lung tissues and airway mucus will be collected for histological and molecular analyses. Mucus plug burden will be quantified using AB-PAS staining, and fibrosis will be assessed using Masson staining. Expression of epithelial-mesenchymal transition (EMT) markers, fibrotic markers, and the mechanosensitive ion channel Piezo1 will also be measured. COPD patients (FEV₁/FVC \<0.70) will be compared with non-COPD surgical controls. The study aims to clarify whether mucus plugs are associated with increased fibrosis and to explore the potential involvement of mechanical-signaling pathways, including Piezo1 activation. Findings may provide new clinical and pathological evidence for mucus-induced fibrotic remodeling in COPD and help identify novel therapeutic targets.