Researchers have discovered a highly promising treatment for lung problems associated with the deadly condition cystic fibrosis.
Cystic fibrosis clogs the lungs with thick, sticky mucus
The treatment involves inhaling a salt water aerosol solution almost twice as salty as the Atlantic Ocean.
This helps to cut damage by restoring a thin lubricant layer of water that normally coats airway surfaces.
Details of the US and Australian collaboration are published in the New England Journal of Medicine.
The research was carried out by the University of North Carolina and the University of Sydney.
Cystic fibrosis is a genetic disorder which causes chronic lung damage due to the build up of excessive amounts of sticky mucus.
In healthy people the water layer lining the airways helps to clear away excess amounts of mucus by sweeping it up into the mouth, where it can be swallowed.
But this water layer is missing in people with cystic fibrosis, so they are unable to prevent mucus from clogging up their lungs. Ultimately, this can lead to respiratory failure.
Sucking water out
The new therapy works by using salt to suck water from the lung tissues out on to their surface.
Researcher Dr Scott Donaldson said: "We are very excited that this simple and inexpensive therapy turned out to be so effective and well-tolerated in patients with CF.
"It gives us great hope that use of this therapy will reduce how often patients feel ill, will slow the decline of lung function over time and will help these people live longer."
The US team used the aerosol to treat a small group of cystic fibrosis patients. They found it significantly improved mucus clearance, lung function and breathing symptoms.
The Australian team then applied it to another 164 patients for a longer period, almost a year.
They found patients needed less antibiotics to treat lung infections, and were more able to attend work or school.
Dr Jim Littlewood, chairman of the Cystic Fibrosis Trust, said the results from the trials were encouraging.
He said: "We welcome new treatment that may improve the chest conditions of those with cystic fibrosis."