Research implicates aggregates of two proteins, known as tau and beta-amyloid, in the development of Alzheimer’s disease.
A new study has tracked the replication and spread of tau in the living human brain for the first time.
It found that, contrary to the prevailing view, local replication of tau is more important for the overall progression of the disease than its spread from region to region.
The research has important implications for the development of drugs to slow or halt the progression of Alzheimer’s.
Alzheimer’s disease is the most common form of dementia, accounting for 60–80% of all cases. It affects around 5.8 million peopleTrusted Source in the United States alone.
In people with Alzheimer’s, plaques of a misfolded protein called beta-amyloid, and fibrous tangles of another misfolded protein called tau, accumulate in the brain and kill nerve cells.
This gradual loss of nerve cells causes shrinkage of the brain and eventually interferes with a person’s ability to form new memories.
Over time, it also disrupts a wide range of other cognitive skills, including language and the ability to navigate once familiar locations.
In the past, the search for an effective treatment for Alzheimer’s disease has mostly targeted the plaques, for example, with vaccines, but so far with limited success Trusted Source.
Meanwhile, there has been growing evidence that the buildup of tangles of tau protein correlates much better with the clinical progress of the disease and damage to the brain than the buildup of plaques.
“Tau isn’t the primary cause of Alzheimer’s, but it is thought to be the most closely correlated with the cascade of changes associated with the disease, including cognition,” Rebecca M. Edelmayer, Ph.D., senior director of scientific engagement at the Alzheimer’s Association, told Medical News Today.
Like cancer cells, aggregates or “seeds” of tau protein can replicate themselves and spread. This has led to the idea that Alzheimer’s progresses when tau seeds spread to unaffected regions in the brain, like secondary tumors in cancer.
However, a new study suggests that the rate at which tau seeds replicate locally is a much more important measure of the disease’s progress than their spread to new regions.
