Review Article
Airway Epithelium Dysfunction in Cystic Fibrosis and COPD
Figure 3
Pathophysiology of airway disease in cystic fibrosis. In cystic fibrosis, loss of normal CFTR function and overactivity of ENaC result in acidification (loss of HCO3ā secretion) and dehydration of the airway surface liquid layer (ASL) disrupting the normal mucociliary escalator. This results in an increase in ASL viscosity, mucus plugging, bacterial colonization, and neutrophil-dominated inflammation. An overabundance of bacterial and neutrophil derived proteases degrades important antiproteases and antimicrobial peptides in the CF airways further compounding an already-overwhelmed impaired innate immune system.