Scientists at Stanford University have determined that the buildup of sticky mucus found in cystic fibrosis is caused by a loss in the epithelial cell's ability to secrete fluid. This research appears as the "Paper of the Week" in the Journal of Biological Chemistry, an American Society for Biochemistry and Molecular Biology journal.
Cystic fibrosis is the most common, fatal genetic disease in the United States. It causes the body to produce thick, sticky mucus that builds up in the lungs and blocks the airways. This makes it easy for bacteria to grow and leads to repeated serious lung infections. The thick, sticky mucus can also block tubes in the pancreas, preventing digestive enzymes from reaching the small intestine.
The disorder results from mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR), a membrane channel regulator essential for proper salt and water movement across some epithelia. Currently, there are two essentially opposite explanations for the inability of the body to clear mucus from the airways in cystic fibrosis. The first is that the defective CFTR is unable to aid in fluid secretion in cystic fibrosis airway glands. The second explanation is that the glands still secrete fluid via non-CFTR pathways, but the fluid is reabsorbed by other channels. In fact, it has been proposed that one of CFTR's functions is to inhibit the activity of a channel called the epithelial Na+ channel (ENaC).