Research Into Mucus

Mucus is essential in the lungs, where it traps germs and pollutants that we inhale. Tiny hairs on the outside of cells, called cilia, propel the mucus out of the lungs and into the throat where the mucus can be swallowed or coughed out.

In people with cystic fibrosis, mucus is dehydrated, becoming so thick and sticky that the cilia are unable to propel mucus out of the lungs. As a result, the mucus clogs the airways, making it difficult to breathe, and traps germs in the lungs. Because the mucus in people with CF also is abnormal in other ways, germs in the mucus are harder to kill, creating an environment that promotes chronic infections.

In people with CF, mucus becomes thick and sticky because of problems with the cystic fibrosis transmembrane conductance regulator (CFTR) protein. The CFTR protein normally forms a channel to transport chloride — a component of salt — through the membranes of cells lining many surfaces in the body, including the surface of the lung. When the CFTR protein is not working correctly or is not present at the cell surface, chloride remains inside cells and cannot attract the water necessary to hydrate the cell surface and materials within the airway, such as mucus. Without the water, mucus becomes dehydrated and takes on a thick, sticky consistency. An abnormal CFTR protein may also affect how certain cells — known as goblet cells — form and release mucus into the airway.

This animation depicts how mucus builds up in the lungs of people with cystic fibrosis.

To advance the development of new treatments, scientists are studying how to restore proper consistency to mucus, enabling its transport out of the lung and facilitating an environment conducive to fighting germs in the airway. 

Researchers are evaluating drugs for their effectiveness in thinning mucus in CF airways. These drugs include CFTR modulators (such as those currently approved* and new options in clinical development) that improve chloride transport — and thus water movement into the airway — and other agents designed to improve or maintain water in the airway through mechanisms other than the CFTR protein. 

*Currently approved modulators work for a majority of people with CF but not everyone. Some people have mutations that do not respond to modulators, while others are not able to tolerate them. 

For more information on current treatments, visit Medications.

Research Into Infections

Research Into Digestive System Issues

Research Into Inflammation

Research Into Cystic Fibrosis-Related Diabetes