Cui L, Li H, Xie M, et al. - In this study, the relationship between ADAM9 levels in sputum and airway epithelium and the clinical characteristics of COPD patients was explored. Researchers included a sputum cohort and a lung tissue cohort examining pulmonary function and computed tomography data in COPD patients, non-COPD smokers, and non-smokers. They diagnosed soluble ADAM9 and interleukin 8 (IL-8) levels in sputum supernatants as well as surface ADAM9 expression in airway epithelium. They calculated emphysema scores were calculated by the percentage of low attenuation area (%LAA-950), and via airway thickening and loss of airway counts, airway remodeling was assessed. In sputum and airway epithelium, airway ADAM9 levels were both increased in COPD patients in comparison with non-COPD controls. Sputum ADAM9 liked to be correlated with inflammatory responses in COPD, while epithelial ADAM9 was more associated with emphysema and airway remodeling.