A team of UK and US biologists believes it has found the underlying cause of asthma, and a cheap way to treat every sufferer. The culprit appears to be an overactive calcium sensing receptor (CaSR) that, until now, was not known to be present in airway tissue. It can potentially be deactivated using a commonly available, cost-effective group of drugs called calcilytics.

Asthmatic symptoms include inflammation, twitching and narrowing of the airway, brought on by triggers such as pollution, pollen and other allergies. Why exactly this response occurs in some people and not others, was unknown until now. We do know that certain groups are at risk -- those that suffered bronchitis as a child, children exposed to smoke and those born prematurely. But the biological cause has remained elusive.


Professor Daniela Riccardi from Cardiff University's School of Biosciences, part of the team responsible for the new discovery, says the presence of CaSR was "completely unexpected". "I previously worked on investigating the role of this particular sensor in other conditions, such as osteoporosis, before we found that this sensor was present in the airways," she tells WIRED.co.uk. "The triggers [pollen etc] release chemicals that activate a sensor in the airways -- if we can block these sensors we can prevent all the symptoms. We knew these chemicals were released during asthma attacks, but didn't know how they worked and didn't have the drug target that could prevent all of these symptoms. Now we know exactly how they work, we can prevent all of these symptoms."

She points out that current treatment options -- steroids, Ventolin and other inhalers -- treat the outcome of the irritation, either the inflammation, twitchiness or narrowing of the airway. No treatment tackles all three, but calcilytics could. They would bring calcium levels down to the same as a non-asthmatic's, and have already been proven to be safe for humans to use when delivered directly to the lungs. "Small molecules [like calcilytics] are also cheaper than steroids and definitely much cheaper than the other available treatment, antibodies," explains Riccardi. She predicts the drugs could be used long term as a preventative measure, but also during attacks.

The drugs could also potentially be used to help those that suffer the most serious asthma attacks, and typically do not respond well to current treatments. In a paper published in the Science Translational Medicine journal, Riccardi and colleagues at King's College London and the Mayo Clinic wrote: "There remains a significant minority of patients whose symptoms fail to be controlled with these approaches and who face chronically impaired quality of life with increased risk of hospital admission and even death, although in a minority such patients account for the major share of asthma health care costs." According to Samantha Walker, director of research and policy at Asthma UK, this category of sufferers makes up just 5 percent of the 5.4 million asthmatics in the UK, but 90 percent of the related asthma healthcare costs.


So far the team's trials have been carried out in mice, but human airway tissue was used to confirm the hypothesis. They have shown that the drugs can be used to prevent inflammation in a model, something Riccardi says "so far nothing out there can match". "A lot of damage to the lungs is done by the inflammation". The team has also tested the drugs in cells in normal patients and saw no effect. "You don't have an overactive sensor in these people," she explains.

The team is looking to raise £10m in funding, but estimates it could be in a position to start human trials in a year or two. Further studies could also look at whether the same treatment could be applied to chronic obstructive pulmonary disease (COPD) and chronic bronchitis, conditions that it's predicted will be the third biggest killer by 2020.

These include chronic obstructive pulmonary disease (COPD) and chronic bronchitis, for which currently there exists no cure. It is predicted that by 2020 these diseases will be the third biggest killers worldwide.