Cystic Fibrosis Advance Shows Promise
Inexpensive Treatment Cuts Infections, Boosts Lung Function
New Insights Into Cystic Fibrosis continued...
That idea was met with only partial success. Newer agents -- such as Pulmozyme, which actually thins mucus -- worked better. Hypertonic saline got shelved.
But cystic fibrosis researchers then made a breakthrough in basic science. They found that an extremely thin layer of water -- just a few hundred thousandths of an inch -- covers lung cells. This thin layer of water keeps mucus moving along. But people with cystic fibrosis don't have this layer of water. Instead of moving away, mucus sticks to their lung cells.
That made the U.S. and Australian researchers take a second look at hypertonic saline. The salt solution, they reasoned, might not be an irritant at all. Instead, the salt might draw water to the surface of cystic fibrosis lung cells, loosening up the sticky mucus.
As it turns out, this seems to be the case.
"These studies show that hydration of the lung surface is the way to go in cystic fibrosis," Boucher tells WebMD. "This was surprisingly effective. It makes sense to make this the base therapy for cystic fibrosis lung disease. If you restore mucus clearance, all the bacteria in the cystic fibrosis lung are in that mucus."
Bacteria are the source of the chronic infections that cause cystic fibrosis flare-ups. Getting rid of some of these germ-filled wads of mucus should mean fewer flare-ups. And that's exactly what happened.
Patients treated with hypertonic saline in the Australian study had 56% fewer flare-ups than those treated with an inactive placebo. Seventy-six percent of the treated patients -- but only 62% of the placebo patients -- were free of flare-ups during the yearlong study.
The patients' lung function improved, too. But that improvement was relatively modest, notes the editorial by Felix Ratjen, MD, PhD, head of respiratory medicine at Toronto's Sick Kids Hospital.
"The effect on lung function isn't all that impressive, but the hypertonic saline improves long-term mucus clearance by making more liquid available on the airway surface," Ratjen tells WebMD. "If there is clearance of mucus from the lower respiratory tract, this may result in less severe infections and lower frequency of infections."