Alzheimer’s disease is the leading cause of dementia. Because of its effects Alzheimer’s is usually thought to be a condition which starts at the brain. While scientists are pushing forward to curing and preventing Alzheimer’s they are trying to look at it from many different angles. Now they are starting to doubt that Alzheimer’s originate in the brain.
Amyloid beta, which forms plaques in Alzheimer's, is brought by blood, so scientists have to find a way for liver and kidney to clear it. Image credit: Garrondo via Wikimedia
There is no doubt that Alzheimer’s is a disease affecting the brain. However, brain is a complex organ, which is difficult to target using modern medicine. Scientists from The University of British Columbia say that paying attention to the entire body may be beneficial for the treatment. For example, medicine targeting kidney or liver could eliminate toxic proteins from the blood before it even reaches the brain. But how do we even know that Alzheimer’s disease can be triggered or accelerated by toxic particles in the blood supply?
It is a very well-known fact that protein called amyloid beta forms clumps, or “plaques” that smother brain cells. That is how Alzheimer’s disease develops. Meanwhile mice naturally do not contract Alzheimer’s disease, which makes them perfect models in this study. Scientists attached a normal mouse to a genetically modified counterpart, which had high levels of the amyloid beta. Since mice do not naturally get Alzheimer’s, the non-modified mouse should have been fine regardless of its partner. However, after a year it did show clear signs of the disease. In fact, not only its brain had plaques, but it also showed distinctive twisted protein strands that form inside brain cells, which disturb brain function and eventually kills brain cells. And other models in the same setting showed signs of impaired brain health just after four months.
Precursor protein of the amyloid beta is found in several other organs. That is why scientists are saying that Alzheimer’s is not just a brain disease – it affects the entire body. Dr. Weihong Song, one of the authors of the study, said: “The blood-brain barrier weakens as we age. That might allow more amyloid beta to infiltrate the brain, supplementing what is produced by the brain itself and accelerating the deterioration”.
Scientists say that these findings may pay the way for a new kind of treatment. New medicine could bind to amyloid beta throughout the body, tagging it biochemically in such a way that liver or kidney could clear it. This would prevent formation of the plaques or at least slow it down significantly. In turn, this would mean that Alzheimer’s disease development would be much slower or, potentially, could be halted completely.
Source: UBC