Alzheimer’s disease is the most common type of dementia in the world, with more than 50 million people suffering from it and, what is even more worrying, a new case is diagnosed every three seconds. In addition, although numerous scientists continue to investigate this neurodegenerative pathology and more than 200 clinical trials have been carried out in the last three decades, an effective therapy to prevent, slow down or treat Alzheimer’s has not yet been found.
Until now, Alzheimer’s had always been considered a brain disease, however, a group of scientists from the Krembil Brain Institute (Canada) has turned experts in this field upside down by proposing a new hypothesis in this regard, since suggests that it would not be a brain pathology, but a chronic autoimmune disorder that attacks the brain. This theory can serve as a basis as a starting point to develop new therapeutic options.
“We don’t think of Alzheimer’s primarily as a disease of the brain. We think it’s a disease of the immune system within the brain,” said Dr. Donald Weaver, co-director of the Krembil Brain Institute and author of the article published in Alzheimer’s & Dementia. “We need new ways of thinking about this disease, and we need them now,” says Dr. Weaver.
The immune system would attack brain cells causing Alzheimer’s
“To date, most approaches to Alzheimer’s research have been based on the theory that a protein called beta-amyloid, which is supposed to be abnormal in the brain, accumulates. And when it builds up, it kills brain cells.” “But we think beta-amyloid is right where it should be. It acts as an immunopeptide – a messenger within our immune system – so that if we have a head injury, beta-amyloid repairs it. If a virus or bacteria appears, beta-amyloid is there to fight it.”
“Beta-amyloid gets confused and can’t tell the difference between a bacterium and a brain cell, so it inadvertently attacks our own brain cells,” causing Alzheimer’s
That’s where the problem lies, Weaver says, because “beta-amyloid gets confused and can’t tell the difference between a bacterium and a brain cell, so it inadvertently attacks our own brain cells. This then becomes what we call an autoimmune disease. The immune system is actually attacking the host, our brain.”
The researchers conducted a detailed search of the scientific literature on Alzheimer’s and analyzed the published data together with the results of their own studies to develop a new mechanistic model (AD 2) for Alzheimer’s, which considers this disease as a chronic autoimmune condition that attacks the brain.
In this AD 2 model, beta-amyloid is recognized as an element that forms a natural part of our immune system, and the metabolism of the amino acids L-tryptophan and L-arginine appear as regulators of innate immunity. Proposing that Alzheimer’s is an autoimmune disease opens the way for new approaches to diagnosing Alzheimer’s and finding innovative therapies, says Dr. Weaver, who concludes, “We’re very excited in our lab. We believe that this autoimmune theory is sound and represents an important conceptual advance.”
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