Friday, April 20, 2007
Bacterial enzyme and cystic fibrosis
Bacterial Enzyme a clue to cystic fibrosis
Published: April 19, 2007 at 3:33 PM
PHILADELPHIA April 19 (UPI) -- The discovery of a bacterial enzyme infecting lungs may hold the key to new treatments for some cystic fibrosis patients, say U.S. researchers.
A team at the University of Pennsylvania found that the bacterial enzyme spingomyelinase (SMase)shuts down a lung protein called cystic fibrosis transmembrane conductance regulator.
CFTR is found in the bacteria that cause pneumonia, some types of anthrax and the opportunistic infections that occur in CF and AIDS, the researchers noted.
In healthy lungs, CFTR helps chloride ions and water cross lung cell membranes and create a thin layer of fluid to keep the airways clear. CFTR is defective in people with cystic fibrosis, so the mucus in their lungs is thicker than normal, the researchers said.
When bacteria that produce SMase enter the lungs, they break down the protective lipid barrier that surrounds CFTR, causing airway mucus to thicken even more and provide a fertile breeding ground for bacteria. The byproducts of the lipid breakdown also trigger inflammation and cell death.
Most people with CF die of lung infections, but clinicians have been puzzled because CF symptoms and infections were often more severe than the patient's CF genetic mutations warranted, the team said.
But finding SMase has cleared up this mystery, the researchers noted, adding that a combination of SMase enzyme inhibitors, antibiotics and supportive measures might improve the length and quality of life of many CF patients.
A report on the research appears in the April issue of the Proceedings of the National Academy of Sciences.