More to asthma than inflammation

U. SOUTHAMPTON (UK) — A new study challenges the traditional concept that asthma is solely an inflammatory condition, a finding with significant implications for future treatment.

“Whilst reducing airway inflammation by inhaling steroids, the traditional treatment for asthma, is very effective for most patients, this does not address the long-term airway wall thickening and scarring that takes place in the lungs of individuals with asthma,” says Peter Howarth, a senior author on the paper from the University of Southampton.

“Known as airway remodeling, this can irreversibly affect lung function. We have shown that this significant problem can be independent of inflammation, which may explain why steroids are not effective at managing all aspects of asthma.”

For the study, published in the New England Journal of Medicine, scientists looked at 48 asthma suffering volunteers, by anlyzing lung airway remodeling by looking at airway samples (bronchial biopsies) taken from the volunteers before and several days after they underwent breathing tests.

To test whether remodeling was caused by inflammation, the participants were split into four groups. One group had airway narrowing and inflammation temporarily induced, one had just airway narrowing but no inflammation induced, and two control groups had no airway narrowing induced.

The team found no significant difference in airway remodeling between the first two groups, which led to their conclusions.

“The important clinical implication of this study is that patients should not only receive treatment to reduce inflammation, but also to prevent airway remodeling,” says Chris Grainge, the study’s lead author.

“Only if this is successful can the long term consequences of the disease be prevented. Asthma currently affects one in five children and one in ten adults in the UK, so it is a very serious burden.”

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