Mucus accumulation in the lower airways is a key feature of
cystic fibrosis (CF)
lung disease. The major component of mucus in CF is not
mucin derived from mucus producing cells but rather
pus that includes viscous material such as polymerized
DNA derived from degraded neutrophils. This has important implications for
mucolytic therapy aiming to improve mucus clearance from the airways, since degradation of
mucin may not be a suitable treatment strategy. In addition, thinning of secretions may not always be beneficial, since it may negatively affect certain aspects of mucus transport such as
cough clearance. While inhaled
N-acetylcysteine has been used as a
mucolytic drug in CF for decades, there is little evidence that it has any beneficial effect.
Dornase alfa has been shown to reduce pulmonary exacerbations and improve lung function and is currently the only
mucolytic agent with proven efficacy in CF. Newer agents targeting other components of CF mucus, such as filamentous actin, are currently in development. Ultimately, drugs that are mucokinetic, which preserve viscoelasticity, rather than
mucolytic may prove to be beneficial for CF
lung disease in the future.