Inhaled hypertonic saline for cystic fibrosis: Reviewing the potential evidence for modulation of neutrophil signalling and function

Figure 2 Effects of hypertonic saline on the airway surface liquid in cystic fibrosis. A: In healthy airway epithelia, CFTR plays a vital role in regulating hydration of the airway surface liquid (ASL) constructed of the periciliary layer (PCL) and the mucus layer; B: Due to defective CFTR in individuals with CF, Cl^- secretion is impaired and Na⁺ absorption through ENaC is increased resulting in dehydration of the ASL and accumulation of thick mucus causing reduced PCL height; C: Treatment with hypertonic saline assists osmosis of water into the ASL and thus rehydrates the mucus and partially restores the PCL allowing for easier clearance of mucus. CFTR: Cystic fibrosis transmembrane conductance regulator.