According to a recent article published in Science Daily, twenty years of research is being challenged by a team of Cambridge University scientists. The new findings of the team of researchers support the theory that Alzheimer’s disease, which is estimated to affect forty-four million people around the world, begins differently than has been described for the past twenty years.
About the Findings
The international team found that contrary to established belief, Alzheimer’s does not start from a single point and then spread between different brain regions. It had been called a chain reaction leading to brain cell death. This observation was identified in mice but does not hold true for humans.
On the contrary, Alzheimer’s starts early reaching various areas of the brain. Toxic protein clusters are produced that kill the cells in these areas slowing the progression of the disease.
According to the New Study
The new study found that clusters of toxic protein arrive at various areas of the brain early and accumulate for decades. If a spread does occur, it is still not the main cause of disease progression.
Georg Meisl, a Cambridge University chemist and lead author, explained that their discovery was the result of detailed PET scan data. The other tools used were the mathematical models that took ten years to develop.
Using Post Mortem Brain Samples
Approximately four hundred post-mortem Alzheimer’s brain samples and one hundred PET scans from people living with Alzheimer’s were used to track the accumulation of tau, a key protein.
Dr. Meisl used the analogy of the COVID pandemic. He talked about how COVID bans between some countries are ineffective in stopping the spread of the virus. He said that the virus easily spreads in those countries because it is already replicating there.
Two very familiar proteins associated with Alzheimer’s are Tau and amyloid-beta. It is generally agreed by researchers that these “aggregates” multiply and cause the protein called amyloid-beta to build into tangles and plaques (collectively known as aggregates). They cause brain cells to die and lead to brain shrinkage.
The team also determined that the number of aggregates doubles every five years. Overall, it takes about thirty-five years for Alzheimer’s to move from stage three where the patient exhibits minor symptoms to stage six, the most advanced stage.
The Discovery Opens Better Understanding of Alzheimer’s Disease
The researchers combined five varied datasets and applied them to a mathematical model. This is where they discovered that the progression in Alzheimer’s disease is replicating in separate brain regions and not in aggregates spreading from one region to another region.
A New and Different Viewpoint
For years the terms ‘chain reaction’ and ‘cascade’ were used in connection with Alzheimer’s disease. The researchers had relied on animal models. The results using mice for studies indicated Alzheimer’s disease spread rapidly.
As aforementioned, the team showed that the replication of tau was actually slow. The UK’s Professor David Klenerman, one of the senior authors, commented how the evolution of biology brought about the proteins’ aggregation. He acknowledged the ability of neurons to stop the formation of aggregates but added that new methods must be developed to bring about improved efficacy.
Looking Forward
The primary key to the Cambridge study focuses on stopping the aggregate replication instead of focusing on their spreading. The team believes that this will be more effective. The researchers plan to study earlier development of Alzheimer’s then expand their studies to other diseases associated with the formation of tau aggregates.
