Researchers have injected a breath of fresh air into the fight against chronic obstructive pulmonary disease by focusing on a small RNA molecule that has altered their understanding of the third most-common cause of death in the world.
The study, published in the journal Science Translational Medicine, found that inhibiting the expression of microRNA-21 reduced inflammation and improved lung capacity and function in mice models of the disease. Antomir-21 — the inhibitor used to suppress microRNA-21 — also reduced the flow of inflammatory cells, such as macrophages, neutrophils and lymphocytes, into the lungs and airways. Lung cytokine production was also inhibited, further preventing the inflammatory response that makes COPD so deadly.
“MicroRNA-21 is a common molecule that is expressed in most cells in the human body and regulates many critical biological processes,” said Phil Hansbro, the study’s senior author and director of the Centenary UTS Centre for Inflammation in Australia. “Our findings demonstrate, however, that microRNA-21 levels increase when it comes to COPD.
“We believe that the development of new drugs that inhibit microRNA-21 may offer up an entirely new therapeutic approach when it comes to COPD treatment.”
Around two million Canadians are living with COPD, a chronic, inflammatory disease that obstructs the flow of air from the lungs, according to the Public Health Agency of Canada. The condition, which occurs more commonly in people suffering from other chronic conditions, such as diabetes and hypertension, is primarily caused by smoking tobacco or prolonged secondhand or passive exposure to tobacco smoke. Emphysema and chronic bronchitis — two conditions that generally occur in tandem — are the biggest contributors to COPD.
People who suffer from COPD can experience difficulty breathing, wheezing and a persistent cough in addition to an increased risk of other serious conditions, such as heart disease and lung cancer. Nearly half of all COPD flare-ups are triggered by seasonal respiratory viruses, with tobacco smoke, air pollution and respiratory infections accounting for most of the remaining hospitalizations.
While hospital admissions for COPD declined during the pandemic because of the some of the health benefits of social distancing and mask wearing, one estimate puts the average hospital cost following a COPD flare up at $10,000 per patient, adding up to an economic burden of $1.5-billion per year. Chronic lung disease, which encompasses COPD, lung cancer and asthma, accounts for more than 6 per cent of Canada’s total healthcare costs, according to the Canadian Lung Association, who said a large number of people with asthma and COPD are undiagnosed and unaware they have either condition.
Identifying a new therapeutic target has changed their understanding of COPD, Hansbro said, opening new avenues for treating a disease that current therapies have had little success in controlling. “The development of effective COPD treatments has been hampered by a lack of understanding of the disease’s underlying mechanisms,” he said.
“Our data defines microRNA-21 as a novel therapeutic target and its inhibitors as a potential new treatment for this major, currently intractable lung disease.”
Dave Yasvinski is a writer with Healthing.ca