Hundreds of thousands of Canadians struggle to survive and take in air because of heart failure. Now scientists in Ontario and New Brunswick have discovered a cause, involving the brain, that rewrites medical textbooks.
“What we were able to find is the true cause of respiratory weakness or dyspneas as being the brain,” said the study’s lead author, Jeremy Simpson, a professor of human health and nutritional sciences at the University of Guelph.
For cardiologists, improving survival rates in heart failure is the priority.
“In heart failure, the patient definitely suffers a lot and so if there are ways in which we can improve not only the survival but also improve the quality of life I think that’s really a win,” Liu said.
Simpson and his colleagues at the University of Guelph in Ontario and Dalhousie University explored how respiratory weakness contributes to dyspnea in mice models of heart failure.
Over nearly six years of painstaking experiments, Simpson’s team discovered that the diaphragm, a large muscle that helps with breathing function, doesn’t work as well in mice models because of faulty signals it receives from the brain.
‘What we were able to find is the true cause of respiratory weakness or dyspneas as being the brain.’
– Jeremy Simpson, University of Guelph researcher
“What was medically known to cause breathlessness has now been unravelled, the true mechanism revealed and importantly solutions presented,” said study co-author Keith Brunt, an assistant professor of pharmacology department at Dalhousie University’s School of Medicine in Saint John, N.B. “Such a fundamental discovery changes the textbooks on breathlessness in heart failure.”
It relates to when false signals from the brain tell the diaphragm to go into overdrive, which tires out the respiratory muscle, said Liu.
Like Liu, cardiologist Dr. Justin Ezekowitz, an associate professor at the University of Alberta in Edmonton, was not involved in the research. He is the co-director of the Canadian VIGOUR Centre, which does clinical research.
“This seems to be a really core mechanism,” said Ezekowitz, a spokesman for Heart & Stroke. “I think that’s why people will be interested.”
If it works the same way in humans, the medical community will also need to better understand what length of treatment is needed to alleviate breathlessness and how we can better balance and combine medications, Simpson said.
The study was funded by the Ontario Thoracic Society, the Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council.