Swiss scientists have discovered that the presence of fluid in the airways of patients affected by cystic fibrosis helps restore their defenses and thus protect them from pathogens.
- In France, 6,000 people suffer from cystic fibrosis.
- This genetic disease affects one in 4,000 newborns.
Cystic fibrosis is a pathology of genetic origin that mainly affects the lungs. It is linked to an abnormality in the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator) protein, which regulates the transport of chlorine through the glandular mucous membranes of the body, according to health insurance. Clearly, in people with this disease, this protein is abnormal. Result: there is a decrease in the water excreted in the mucous membranes, inflammation and thickening of the mucus covering it. As a result, the quality of mucus is impaired, it is no longer able to capture unwanted bacteria and eliminate them.
An in vitro model reproducing the epithelium of patients
“It is not yet known whether the composition and/or presence of airway surface fluid is sufficient to prevent infection,” said researchers from the University of Geneva in Switzerland. To find out for sure, they decided to carry out a study published in the journal cells. In order to carry it out, the team developed an in vitro model using human lung cells. The latter reproduces the epithelium (a tissue formed of juxtaposed cells) of the airways of healthy patients and patients with cystic fibrosis. Next, the authors compared the response of epithelial cells, carriers of a mutation in the CFTR gene, to a bacterial infection, to which they had added either healthy, hydrated mucus or a physiological saline solution.
“Rehydration of the respiratory tract is beneficial” to fight against infections
According to the results, the presence of physiological saline solution attenuated the disruption of the airway epithelial barrier. Thus, once rehydrated, the epithelial cells, carrying a mutation of the CFTR gene, were protected from bacterial infection.
“The presence of fluid, regardless of its composition, restored the airways and protected them from infection. Surface hydration is sufficient to tighten the junctions between cells and protect the integrity of the epithelium against colonization bacteria, even when the CFTR protein is not functioning”, explained Juliette L. Simonin, author of the work, in a statement.
“Our results provide evidence that rehydration of the airway surface is beneficial. The challenge now is to find a simple way to do this in all people with the disease, regardless of the causative mutation,” concluded Marc Chanson who also participated in the study.