For the first time, scientists have identified the potential root cause of asthma and an existing drug that offers a new treatment.
Asthma is a chronic condition in which the airways that carry air to the lungs are inflamed and narrowed. Asthma causes recurring periods of wheezing, chest tightness, shortness of breath, and coughing. The coughing often occurs at night or early in the morning. Some people have mild asthma symptoms, or only experience asthma symptoms in response to certain activities like exercising. Other people have more serve and frequent symptoms, which may need treatment with medication.
Until now, the cause of asthma was unknown. Scientist knew that asthma was caused by inflammation in the small tubes, but did not know what was triggering it. In a breakthrough, researchers at Cardiff University and Kings College London identified which cells cause the airways to narrow when triggered by irritants like pollution, allergens, cigarette smoke and car fumes. These triggers release chemicals that activate CaSR (Calcium Sensing Receptor) in airway tissue and drive asthma symptoms. Crucially, drugs already exist which can deactivate CaSR. They are known as calcilytics and are used to treat people with osteoporosis.
"Our findings are incredibly exciting," said Professor Daniela Riccardi, from Cardiff University School of Biosciences. "If we can prove that calcilytics are safe when administered directly to the lung in people, then in five years we could be in a position to treat patients and potentially stop asthma from happening in the first place.”
The team used mouse models of asthma and human airway tissue from asthmatic and non-asthmatic people to reach their findings. Professor Riccardi and her collaborators are now seeking funding to determine the efficacy of calcilytic drugs in treating asthmas that are especially difficult to treat, particularly steroid-resistant and influenza-exacerbated asthma, and to test these drugs in patients with asthma.
“Five per cent of people with asthma don't respond to current treatments so research breakthroughs could be life changing for hundreds of thousands of people, said Dr. Samantha Walker, Director of Research and Policy at Asthma UK.
"If this research proves successful we may be just a few years away from a new treatment for asthma, and we urgently need further investment to take it further through clinical trials.” The scientists are hoping that clinical trials will begin soon.
The discovery could also pave the way for new treatments for 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.