Fish Providing Clues About Human Heart Disease

September 20, 2011 - News Release

A new study led by University of Guelph biologists on how fish hearts keep ticking in cold or warm water might point the way to treating or preventing heart disease in humans.

Rainbow trout can actively remodel their heart tissues to adapt to changing temperatures, according to a recent study by U of G researchers that appeared in PLoS One, published by the Public Library of Science.

Learning how genes and proteins accomplish that feat in trout hearts might yield clues about treating or preventing heart damage in humans, said lead author Jordan Klaiman, a PhD student in the Department of Integrative Biology. “In the long term, the goal is to apply what we learn in trout hearts to human disease.”

Fish can add muscle or connective tissue to bulk up their hearts in cold temperatures, but they can also remove heart tissue in warmer water. That allows the organ to remain active over temperatures ranging from 4 C to 17 C, said Klaiman.

In humans, changes in heart temperature dramatically impair organ function, said Prof. Todd Gillis.

Human hearts can enlarge with cardiac disease. Uncontrolled growth of the cardiac muscle can lead to injury or even sudden cardiac death. Researchers need to learn how expression of pertinent genes and proteins changes as this condition develops.

Intriguingly, the heart also grows with aerobic exercise, although Gillis said scientists don’t completely understand how the organ or the body distinguishes between “good” and “bad” stresses. “That’s a prize-winning question,” said Gillis, who is also interested in how mammals hibernate in cold without suffering heart damage.

The researchers studied adult trout in U of G’s Hagen Aqualab. Other co-authors study at McMaster University and the University of Manchester.

Earlier this year, Gillis published three papers on studies of heart proteins and tissues in fish. He studies heart physiology with biologists in his department and in the Ontario Veterinary College.

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