Oct. 31 (UPI) -- A new discovery could change the way scientists think about where Alzheimer's disease originates in the body.
It has long been believed that Alzheimer's disease, the leading cause of dementia, begins in the brain, but a new study by researchers from the University of British Columbia and researchers in China found that the neurodegenerative disease could actually begin elsewhere in the body.
The study, published Tuesday in Molecular Psychiatry, showed how toxic amyloid-beta proteins could be targeted in the kidney or liver to eliminate the protein from the blood before it ever reaches the brain.
Amyloid-beta is also found in blood platelets, blood vessels and muscles, along with being a precursor protein in other organs.
In patients with Alzheimer's disease, amyloid-beta proteins can form clumps or plaques that kill brain cells.
Researchers used a process known as parabiosis, where two specimens are attached together surgically in order to share the same blood supply for several months. 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.
The study showed that the normal mice joined genetically to the modified mice for a year contracted Alzheimer's when the amyloid-beta protein traveled from the genetically modified mice to the brains of the normal mice.
The normal mice also developed twisted protein strands or tangles that form inside brain cells, killing the brain cells along with other Alzheimer's-related damage including brain cell degeneration, microbleeds, inflammation and an impaired ability to transmit signals involved in learning and memory.
"That might allow more amyloid beta to infiltrate the brain, supplementing what is produced by the brain itself and accelerating the deterioration. Alzheimer's disease is clearly a disease of the brain, but we need to pay attention to the whole body to understand where it comes from, and how to stop it."