Researchers have found a potential new treatment for thousands of asthma patients who experience a ‘late phase’ of symptoms several hours after exposure to allergens, causing breathing difficulties which can last up to 24 hours.
In research on mice and rats, scientists from Imperial College London have now found evidence that the late asthmatic response happens because the allergen triggers sensory nerves in the airways.
These nerves activate reflexes, which trigger other nerves that release the neurotransmitter acetylcholine, which causes the airways to narrow. If the findings translate to humans, it would mean that drugs that block acetylcholine – called anticholinergics – could be used to treat asthma patients that experience late phase responses following exposure to allergens.
“Many asthmatics have symptoms at night after exposure to allergens during the day, but until now we haven’t understood how this late response is brought about,” said Professor Maria Belvisi, from the National Heart and Lung Institute at Imperial College London, who led the research.
“Our study in animals suggests that anticholinergic drugs might help to alleviate these symptoms, and this is supported by the recent clinical data. We are seeking funding to see if these findings are reproduced in proof of concept clinical studies in asthmatics.”
The researchers hypothesised that sensory nerves were involved after observing that anaesthesia prevented the late asthmatic response in mice and rats. They succeeded in blocking the late asthmatic response using drugs that block different aspects of sensory nerve cell function, adding further evidence for this idea.
The study has been published in the journal Thorax.