As common as asthma is, exactly how it starts remains murky. Scientists have now identified a new root cause, and importantly a new angle for treating the disease that can prevent the main symptoms.
According to WHO, asthma affects around 262 million people worldwide, but despite its prevalence there’s still much scientists don’t understand about the condition. It’s usually treated as an inflammatory disease – triggers like pollen or dust set off inflammation that narrows the airways and makes it difficult to breathe. Inhaler medications can relieve this by relaxing the airways and calming inflammation.
But the new study points to a different root cause, of which inflammation is itself a symptom. When the airway muscles contract – known as bronchoconstriction – the epithelial cells that line the airways are 'squeezed out' and later die. With fewer of these cells acting as a barrier, the chances for future asthma attacks increase.
“As cell biologists who watch processes, we could see that the physical constriction of an asthma attack causes widespread destruction of the airway barrier,” said Professor Jody Rosenblatt, lead author of the study. “Without this barrier, asthma sufferers are far more likely to get long-term inflammation, wound healing, and infections that cause more attacks. By understanding this fundamental mechanism, we are now in a better position to prevent all these events.”
The team made the discovery in mouse models, and importantly also found a potential way to prevent too much cell extrusion. The chemical compound gadolinium was previously found to block the process, and in the new study the researchers showed that it worked in mice to prevent cell damage and inflammation associated with asthma attacks.
“Current therapies do not prevent this destruction – an inhaler such as Albuterol opens the airways, which is critical to breathing but, dishearteningly, we found it does not prevent the damage and the symptoms that follow an attack,” said Rosenblatt. “Fortunately, we found that we can use an inexpensive compound, gadolinium which is frequently used for MRI imaging, to stop the airway damage in mice models as well as the ensuing inflammation and mucus secretion. Preventing this damage could then prevent the build-up of musculature that cause future attacks.”
Of course, mice aren’t humans, so there’s no guarantee that these results will necessarily carry across to humans. But the team says that the new study could help lead to new types of asthma therapies that aren’t just about treating symptoms.
The research was published in the journal Science.
Source: King’s College London