NewsThursday, 18. June 2009
Dry airways – are they a major factor in diseases of the respiratory tract?
A German-American research group used a transgenic mouse model to demonstrate that osmotic regulation disorders of the pulmonary epithelial cells bring about partial dehydration of the liquid film on the surface of the respiratory tract. Such dehydration of the respiratory tract was sufficient to trigger permanent changes in the lung's surface – changes resembling those that are typical of pulmonary diseases such as asthma, COPD and cystic fibrosis.
In the case of cystic fibrosis excessive dryness of the surface of the respiratory tract had already been identified as a key factor for development of the clinical picture. In this disease a defective gene disrupts ion exchange between the epithelium of the lung and its surface film. The scientists from Heidelberg, Michigan and North Carolina have now used mice with gene overexpression of the epithelial sodium channel to prove a direct link between this genetic defect, the formation of obstructive mucus and the development of inflammatory processes in the respiratory tract. The symptoms observed in these mice are not only typical of cystic fibrosis but also of other pulmonary diseases such as asthma or COPD . From these results the authors conclude that serious chronic diseases of the respiratory tract can be caused merely by excessive dryness of the airway surfaces. They therefore see hydration of the lung's surface as a new therapy objective in order to restore its film of liquid.