Guelph prof finds way to help heart failure patients

Researchers learn what’s behind breathing troubles

GUELPH — A University of Guelph researcher discovered the surprising cause of shortness of breath among people with heart failure, and an effective new treatment for the common complaint.

Best of all, it won’t take years or even decades to develop medications. Drugs that are currently available can be used to ease the strain on both the heart and respiratory system.

“We can begin applying this research knowledge now to how we treat patients,” said Jeremy Simpson, a professor in the department of human health and nutritional sciences and the study’s lead author.

The groundbreaking results of the five-year study links shortness of breath in heart failure to a hormonal imbalance in the brains of mice.

Heart patients commonly suffer from dyspnea, or shortness of breath.

“We really didn’t know why,” Simpson said.

Generally it was thought that fluid buildup in the lungs made it difficult for patients to breathe, and it was assumed this sideeffect couldn’t directly be treated.

“All cardiac studies are directed at the heart and looking at what’s going on in the heart,” Simpson said.

And mostly research looks at advanced heart failure.

For this study, the researchers started out looking at mice as heart failure developed and they discovered that the diaphragm, the main muscle used for breathing, was being overworked.

Then they had to figure out why.

People with heart failure are known to have increased levels of norepinephrine and angiotensin, and that imbalance causes high blood pressure and heart failure.

It turns out, the researchers discovered, that the two hormones indirectly affect the diaphragm by getting into the brain and sending signals that put the diaphragm muscles into overdrive. “Eventually they become weak,” Simpson said.

Suppressing those hormones using beta blockers and angiotensin receptor blockers that are able to pass through the bloodbrain barrier can prevent that. The key is finding the right drug for the right patient to best treat both the heart and respiration.

The findings could substantially improve the quality of life for heart patients, and also for people with other diseases involving shortness of breath.

“It’s really exciting that we found out we can treat it,” Simpson said. “We expect a lot of studies will come out of this.”

The majority of funding for the study came from the Heart and Stroke Foundation of Canada and the Ontario Thoracic Society, and Simpson said the study’s results point to the value of research and the importance of funding from both the government and public.

“It is benefitting them,” he said.

“This is why we need to keep funding research at all levels.”

Simpson worked on the study, which appeared this week in Science Translational Medicine, with Dalhousie University professor Keith Brunt, and his team of graduate students Andrew Foster, Mathew Platt and Jason Huber.