Dr. Donald Weaver, Senior Scientist at UHN's Krembil Brain Institute, believes this theory could one day lead to new therapeutics for Alzheimer's. "We need new approaches and we need them now." (Photo: Krembil Brain Institute)

By 2030, nearly a million Canadians will be living with dementia. The vast majority will be diagnosed with Alzheimer's disease, the most common form of dementia.

Alzheimer's impacts more than 50 million people around the world, with a new person being diagnosed every three seconds. Yet, despite more than 200 clinical trials in the past 30 years, there are no disease modifying therapeutics to prevent, halt or treat Alzheimer's.

"We need new ways of thinking about this disease, and we need them now," says Dr. Donald Weaver, a Senior Scientist at UHN's Krembil Brain Institute.

Dr. Weaver is the author of a recent paper detailing a new theory of Alzheimer's – not as a brain disease, but as a chronic autoimmune condition that attacks the brain. This novel research was recently published in the journal of the Alzheimer's Association, Alzheimer's & Dementia.

"We don't think of Alzheimer's as fundamentally a disease of the brain. We think of it as a disease of the immune system within the brain," says Dr. Weaver.

"To date, most of the approaches in Alzheimer's research have been based upon the theory that a protein called beta-amyloid, which is supposedly abnormal in the brain, clumps up. And when it clumps up, it kills brain cells.

"But we believe beta-amyloid is right where it should be. It acts as an immunopeptide – a messenger within our immune system – so that, if we have head trauma, beta-amyloid repairs it. If a virus or a bacteria comes along, beta-amyloid is there to fight it."

And that's where the problem occurs, says Dr. Weaver.

"Beta-amyloid gets confused and can't tell the difference between a bacteria and a brain cell and so it inadvertently attacks our own brain cells," he says. "This, then, becomes what we call an autoimmune disease. The immune system is actually attacking the host, our brain."

In this new theory, it is believed that beta-amyloid, a 'messenger' protein within the immune system, get confused and attacks brain cells. (Photo: Getty Images)

This new theory of Alzheimer's as an autoimmune condition has been getting a lot of attention internationally.

Dr. Weaver was announced as one of the recipients of the coveted Oskar Fischer Prize, awarded to scientists worldwide who are investigating new theories of Alzheimer's. His recent essay “Alzheimer's might not be primarily a brain disease. A new theory suggests it's an autoimmune condition" in The Conversation – an independent source of news from the academic and research community, has been viewed more than a million times and translated into several languages, including French, Spanish, Indonesian and Bulgarian.

"Tangible rethinking about Alzheimer's disease as an autoimmune disease, and beta-amyloid as a normal part of our immune system, opens the door to new avenues and approaches to develop innovative and much-needed new therapies," says Dr. Weaver.

"I have spent the last 30 years trying to come up with new approaches and new drugs to treat Alzheimer's disease," he says. "We're pretty excited in our lab. We think that this autoimmune theory is very sound.

"We think that it does represent a significant step forward and a new way of thinking and we're excited about finding the molecules that hopefully, one day, leads up to a very useful drug."

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