Hamburg, Germany  - German researchers have found that the symptoms of cystic fibrosis can be prevented in an animal model by spraying amiloride into the lungs of young mice.

Cystic fibrosis is a genetic disease that leads to the dehydration of the mucous membranes in the lungs, intestines and other organs. It is the most common, life-shortening genetic disease in Western Europe and North America.

The Heidelberg University Hospital researchers have succeeded in preventing cystic fibrosis lung disease in an animal model by spraying amiloride into the lungs of young mice. This is the first therapy to successfully attack the root cause of the widespread hereditary disease in a living organism.

When mice are given inhalation treatment with the drug in the first days of life, no thick mucus forms in the lungs and airway inflammation and chronic lung damage can be prevented.

The researchers at the paediatrics department at Heidelberg University Hospital thus demonstrated for the first time that preventative therapy of lung disease is possible for cystic fibrosis. Their study was published in the American Journal of Respiratory and Critical Care Medicine.

The cause of all symptoms of cystic fibrosis are defects at certain locations in the genetic make-up - a mutation in what is called the CFTR (Cystic Fibrosis Transmembrane Conductance Regulator gene) leads to loss of salt and water and thus dehydration of the surfaces of the mucous membranes in the lungs, intestines and other organs.

Thick, sticky mucus forms clumps that cannot be easily cleared. This leads to chronic airway inflammation and other serious respiratory and digestive disorders.

There is currently no treatment available that targets airway surface dehydration, ie, the root cause of the disease; so far it is only possible to treat symptoms such as pneumonia, respiratory distress and lack of oxygen.

Using the mouse model he developed, Dr Marcus Mall, physician scientist and head of the Cystic Fibrosis Centre at Heidelberg University Hospital, showed that certain "hyperactive" sodium channels in airway cells are responsible for the increased absorption of salt and water from airway surfaces.

In this study, Dr Mall's team tested whether inhibiting these hyperactive sodium channels with amiloride could improve hydration of the airway surfaces and prevent lung damage.

They found that in a mouse model, amiloride administered in the first few days of life prevents the typical symptoms of cystic fibrosis and the development of chronic lung disease.

However, if the symptoms were already present, the treatment brought no improvement. Chronic lung damage apparently prevents the amiloride from being effective.

"This indicates that the lung damage caused by the disease may be irreversible," said Dr Mall. (dpa)