Learning how fish survive in deep freeze may help biologist keep human hearts beating
BY ANDREW VOWLES
He hasn't marched with penguins. But Prof. Todd Gillis, Integrative Biology, found himself ice fishing one day with several Adelie penguins that had plunked themselves down at his fishing hole in Antarctica. “They're very curious because it's so boring,” says Gillis, who returned to his alma mater last summer for a faculty appointment.
Boring for the birds, perhaps, but not for this biologist whose studies have taken him from one frozen end of the Earth to the other. Besides that memorable field trip to the McMurdo Research Station, he has gone diving for fish, shellfish and crustaceans in Canada's Arctic. By learning more about how these creatures survive in some of the world's most frigid waters, he hopes to help improve survival odds for human heart patients.
What does studying cold tolerance in Arctic critters have to do with cardiovascular disease, responsible for almost 75,000 deaths in 2002 and the single greatest killer disease in Canada? Gillis says the same proteins that keep the hearts of fish beating under frigid temperatures also help control contractions of heart muscle in other animals, including humans.
Mutant proteins in people may cause heart muscle diseases such as hypertrophic cardiomyopathy (also known as “big heart”), in which a thickened heart wall makes it harder for the organ to pump blood. Cardiomyopathies may cause heart rhythm disorders and lead to sudden cardiac death. “This is a hot topic in cardiac labs,” says Gillis.
By learning how the so-called troponin protein complex determines calcium sensitivity in cold-adapted fish, he may help in understanding how human hearts work — or don't work. Calcium is what triggers heart muscle contractions, he says, explaining that cardiovascular disease often derails calcium transport.
His research may help other researchers and clinicians — including his former PhD supervisor at Simon Fraser University, where Gillis studied trout hearts with funding from the Heart and Stroke Foundation — to develop treatments such as genetic medicine to fix the problems. In effect, he says, “How to make a human heart work like a fish heart?”
His specific interest lies with the basics of protein structure and function, including how evolution drives the design of proteins underpinning all of life.
Here at Guelph, Gillis has found a number of potential collaborators for his work. His next-door neighbour in the Axelrod Building is recently arrived Prof. Doug Fudge, who studies slime proteins made by hagfish. They hope to obtain research funding together for equipment to study muscle function and biomechanics, including how proteins work within and outside the heart.
Gillis is also discussing possible collaborations with Prof. John Dawson, Molecular and Cellular Biology, who is already working with Prof. Glen Pyle, Biomedical Sciences, on studies of heart disease in Doberman pinschers and people.
Gillis has also reconnected with his former master's supervisor, Prof. Jim Ballantyne. They plan to study fish from Eastern Canada all the way to the Arctic to look for genetic and population differences that help them adapt to cold. They're particularly interested in how fish may respond not just to cold but also to the effects of global warming.
Even warming their ocean home by a few degrees may cause havoc for residents of Arctic waters, says Gillis, particularly if that change occurs over a relatively short period. Will cold-dwelling species be able to adapt quickly enough? In effect, they may become sentinels for the wider impact of warmer temperatures around the planet, he says.
It was during his undergraduate work at Guelph that he first visited Igloolik in the Arctic with Ballantyne. “That opened my eyes to see the extremes,” says Gillis. During his scuba dives beneath the ice with his supervisor to collect specimens, he was amazed to see fish and invertebrates swimming with all the insouciance of tropical species in an aquarium.
He could hardly claim to be cold-adapted himself. “You hit the water, and it feels like your head is going to explode,” he says, recalling having to grit his teeth to ignore the constant headache.
After completing a master's degree here on temperature adaptation and gill membranes in mollusks, he moved to British Columbia for his doctorate. While there, he received a grant from the U.S. National Science Foundation to spend a month and a half at McMurdo — what Gillis calls “the world's most expensive field course.”
(He contrasts the near-luxurious amenities — climbing walls, a bowling alley, sophisticated laboratories — at the research base on Ross Island with the spartan conditions nearby in the wooden hut erected by explorer Robert Falcon Scott on his early 1900s expedition to the South Pole. “It's like you're walking back into time,” he says, recalling a visit to the Scott hut.)
Gillis went on to spend three years in the bioengineering department of the University of Washington's school of medicine before returning to Guelph.
His research interest stems from his close-up look at nature during summers at the family cottage in Tobermory. That's where he learned to dive in Fathom Five Marine Park, considered one of the best wreck diving sites in Canada. Both of his sisters also learned to dive there, including his older sister, Patricia Gillis, who studied ecotoxicology at Guelph before completing a PhD at the University of Waterloo. She's now studying environmental pollutants and fish physiology as a post-doc at McMaster University.
Acknowledging that much of his work may sound more like protein biochemistry than zoology, Gillis says it's important to study protein function within the larger framework of natural sciences and ecology. That explains his move back to Guelph and his recently reconstituted department within the College of Biological Science.
“This is integrative research — hearts, human health, the environment.”
