Asthma is thought to affect more than 250 million people worldwide and is responsible for hundreds of thousands of deaths each year. Research into a cure for the condition would make a major difference for a significant number of people.
Scientists have now come up with the beginnings of a potential long-term treatment for asthma. Crucially, it doesn't just try and treat the symptoms of the condition but actually targets one of the causes of those symptoms.
It works by blocking the movement of a type of stem cell called a pericyte. Most often found in the lining of blood vessels, pericytes are known to thicken the airways of people with asthma when an allergic and inflammatory reaction happens, making breathing more difficult.
"By targeting the changes in the airway directly, we hope this approach could eventually offer a more permanent and effective treatment than those already available, particularly for severe asthmatics who don't respond to steroids," says biologist and pharmacologist Jill Johnson from Aston University in the UK.
In people with asthma, the airways become constricted, leading to shortness of breath and wheezing. Steroids can help by relaxing these airways and reducing inflammation, but they're not a long-term or permanent solution.
Stopping pericytes from traveling to the airway walls – where they turn into muscle cells and other cells that make the airway thicker and more rigid – would impact one of the underlying causes of shortness of breath.
To get at the pericytes, the researchers targeted a protein called CXCL12. In tests on asthmatic mice, blocking the signal from this protein saw a reduction in symptoms in just a week and the clearing up of all asthmatic symptoms in two weeks.
"We were able to mitigate pericyte uncoupling from the airway microvasculature, resulting in decreased airway smooth muscle accumulation and improved symptom scores," write the researchers in their published paper.
To put it another way, compared with control mice, the mice who had received the treatment had thinner airway walls. It's a promising sign for the effectiveness of the treatment, which researchers also tested on human tissue cells in a lab.
It's not the only form of relief that could soon be coming for those with asthma, either. Last year we heard about an effective asthma vaccine that was in development, while a few months back, scientists showed how a new class of immunotherapy drugs could also potentially be used as an asthma treatment.
As you might expect, there's still a long way to go before this is available as a treatment, even if it's an exciting avenue of research so far. To begin with, the treatment needs to be developed and made safe for human testing.
"Our work is still at an early stage and further research is needed before we can begin to test this in people," says Johnson.
The research has been published in Respiratory Medicine.