Alzheimer's may begin outside the brain

Dementia breakthrough

"If these findings do prove to be relevant to people, it highlights the continued importance of developing treatments that target amyloid in the body as well as the brain".

"That might allow more amyloid-beta to infiltrate the brain, supplementing what is produced in the brain itself and accelerating the deterioration", he said.

Aβ, a protein that can form plaques and smother brain cells, is generated in both brain and peripheral tissues.

Scientists from Canada and China have found evidence that the neurological disorder Alzheimer's starts outside the brain.

The article's senior authors, UBC's Weihong Song, Ph.D., and Chongqing's Yan-Jiang Wang, M.D., Ph.D., emphasized that the Aβ traveled from the genetically modified mice to the brains of their normal partners, where it accumulated and began to inflict damage.

But this new research indicates it could be started by breakdowns elsewhere.

The team from the University of British Columbia were inspired to look at the earlier origins of the disease, which now has no cure, because if their suspicions were correct then drug therapies could target other easier-to-reach organs than the brain. They used parabiosis on two groups of mice, one that did not have Alzheimer's disease and mice modified to carry a mutant human gene to produce high levels of amyloid-beta leading to Alzheimer's disease.

Their brains were infected with toxic protein that had spread from the genetically modified mice via the animals' shared blood circulation, the scientists believe.

Not only that but the mice developed the twisted "tangle" protein strands that form inside brain cells, disrupting their function and other signs of Alzheimer's-like damage including brain cell degeneration, inflammation and microbleeds.

Science is looking beyond the brain to better understand Alzheimer's disease.

The ability to transmit electrical signals involved in learning and memory was impaired in the normal mice after just four months. But until these experiments, it was unclear if Aβ from outside the brain could contribute to Alzheimer's disease.

'The protein can get into the brain from a connected mouse and cause neurodegeneration, ' Professor Song said.

After decades of research, there is no approved drug treatment that can remove or destroy amyloid-beta inside the brain.

Alzheimer's affects more than 5 million Americans, but can only be officially diagnosed via autopsy, meaning there's no real means of detecting it while the patient is even alive, let alone in an early and potentially more treatable stage.



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