Peter KannuDr. Peter Kannu, MB, ChB (Otago), PhD, DCH, FRACP
Clinical Geneticist, SickKids
Associate Scientist, SickKids Research Institute
Assistant Professor, Pediatrics, University of Toronto

Osteoarthritis (OA), the world’s most common joint disease, is marked by the ongoing breakdown of cartilage, the tissue that cushions joints and protects bones. Cartilage is actually made mostly of water, moving in and out of cells. Does water hold a clue to how cartilage breaks down and how osteoarthritis develops?

This is the question facing Dr. Peter Kannu at Toronto’s Hospital for Sick Children (SickKids), and its potential answer is the reason behind the operating grant he received from the Arthritis Society. The Arthritis Society believes that this kind of idea, with the potential for enormous upside, represents an important investment in the fight against arthritis.

For three years, Dr. Kannu and a research assistant will study aquaporins: these are water channels that open and close, regulating water entering and leaving cells. We already know that aquaporins behave differently in people with knee OA. Also, in an arthritic environment, cartilage cells inflame and begin laying down calcium to become more bone-like, thus losing that vital cushion. Dr. Kannu is examining the role that water channels could play, and if that process could be prevented.

The researchers are working with two groups of mice: those with aquaporins (control group) and those without. They will introduce instability to the knee joints to see if the absence of the water channels actually protects mice from knee OA, or if the disease develops faster. They also plan to test various medications on mice without aquaporins in hopes of finding a potential OA treatment.

The team will also explore ways to detect the disease earlier. “One problem with osteoarthritis prevention is that current diagnostic tools can only identify it in later stages,” says Dr. Kannu. “By that stage, the horse has already bolted. We want to develop new tests. We wonder if these water channels could provide a clue for early diagnosis, at the time where people are complaining of pain and discomfort but arthritis is decades down the road.”

Dr. Kannu, who has OA in his neck, is very interested in uncovering an explanation for why some people develop severe arthritis while others have only a mild case — and if the former should be more aggressively managed. He says current OA treatments are limited to pain-relieving drugs and surgical procedures.

“We have no drugs that can stop OA or slow it down,” he says. “But there is a good deal to be hopeful for, because as techniques and technology get more sophisticated, we have a better way to answer questions that have puzzled us for a long time.”

He’s doing just that in a lab at SickKids, a lab paid for in part by the many Canadians who have donated to the Arthritis Society to fund new research. As Dr. Kannu explains, “I wouldn’t be able to do this without your support.”

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