Groundbreaking N.B.-led study helps heart patients breathe easier

A groundbreaking, all-Canadian study led by a New Brunswick researcher will allow heart failure patients around the world to breathe more easily.

Patients with heart failure and hypertension often rank breathlessness among their chief complaints, according to Dr. Keith Bruntm, an assistant professor of pharmacology at Dalhousie Medicine New Brunswick in Saint John.

Brunt co-wrote the study published in the journal Science Translational Medicine with Dr. Jeremy Simpson of the University of Guelph.

"It's the one thing patients want to get back," Brunt said. "The feeling of not having enough air keeps you from doing basic things, like going to get groceries or playing with your grandkids."

The study found using hormone-suppressing drugs that cross the blood-brain barrier, reaching the part of the brain responsible for respiratory control, can resolve the shortness of breath experienced by most patients.

"It's kind of a big deal," Brunt said.

Best of all: the drugs they tested are already on the market.

That the drugs are already available and already generic, is "one of the most exciting things [about the research], and why we got into this top journal," Brunt said.

Pinpointing cause of breathlessness

Scientists have long known that as heart failure progresses, the diaphragm — the main muscle we use to breathe —   becomes overworked.

But the reason why wasn't entirely understood.

The team discovered that in heart patients, hormones from the heart and kidney travel to the brain, confusing the areas of the brain that regulate breathing.

The diaphragm then goes into overdrive, causing a crippling sensation of shortness of breath, or "air hunger." The study found the hormones norepinephrine and angiotensin, found in high levels in people with heart failure, are responsible for weakening the diaphragm.

Armed with these findings, doctors can better prescribe drugs to resolve the symptoms of heart failure and hypertension patients.

The drugs "can start being used today," Brunt said. "We can start talking to clinicians, cardiologists, and respirologists, and show them the path we've discovered of how the brain is messing up the breathing muscles — and we can use drugs that are already generic and already on the market."

7 years of detective work

The study is the culmination of more than seven years of research by a team of 11 researchers, including doctors and graduate students.

Many of the students involved in the study worked 12-hour days, six days a week, Brunt said.   

"You start off with a hypothesis — and we proved ourselves wrong in the first two years," he said. "Then we spent the next five years figuring out why we were wrong. You just follow the data, like detective work. You just have to be patient and persevere through it."

It's all the more a triumph given the difficulty of securing funding for scientists in the health realm in recent years, Brunt said.

"We really appreciated the groups like the Lung Association, the Heart and Stroke Foundation, and the Natural Sciences and Engineering Research Council of Canada that allowed us to do this," he said.

'Globally significant' findings

Brunt and Simpson are  now working with cardiologists and respirologists at the New Brunswick Heart Centre in Saint John to develop a clinical study that will monitor the medications of patients with hypertension and heart failure.

"We are going to be looking at patients who have these conditions and see if we are appropriately medicating them, and potentially switching medications up to make sure that we can respond to that breathlessness," Brunt said.

The findings could also lead to better treatments for patients with other diseases, including like sleep apnea and COPD.

This week, the time team travels to Washington, D.C. to present the findings to the 2017 International Conference of the American Thoracic Society.

"My colleague in Guelph and myself are just elated by it," Brunt said.

"This is not just putting us on the map nationally, medically speaking. This is putting us on the map globally."