Tau protein in Alzheimer's disease spreads like Mad Cow Disease in the human brain. When we discover Mad Cow Disease in cattle, we do not eat beef until we know that the meat is not contaminated. Therefore the tau protein is mutated in the human brain, until we do further research on the mutated tau protein to find out why it mutates we cannot control or cure Alzheimer's.
At the end of this article is another short article which explains what tangles are in the context of Alzheimer's disease.
From BBC Health News:
Scientists have shown a rogue protein thought to cause Alzheimer's can spread through the brain, turning healthy tissue bad.
They believe the tau protein may share characteristics with the prion proteins which cause vCJD.
When injected into the brains of healthy mice it triggered formation of protein tangles linked to Alzheimer's.
However, experts stressed the Nature Cell Biology study did not mean tau could be passed from person to person.
This does not mean that these diseases are infectious in the same way as mad cow disease and human CJD
Professor David Allsop
Tau is a protein present in all nerve cells, where it plays a key role in keeping them functioning properly.
But a rogue form of the protein can trigger the formation of protein clumps within nerve cells known as neurofibrillary tangles.
It is thought that these tangles are likely to be a major cause of Alzheimer's disease.
In the latest study researchers, led by a team from University Hospital, Basel, extracted sections of brain from mice expressing a mutant form of human tau protein.
These extracts were injected into specific regions in the brains of healthy mice.
Analysis showed that this induced normal human tau proteins in the healthy mice to clump together to form neurofibrillary tangles.
These newly-formed tangles were also able to spread to nearby regions in the brain.
Another type of rogue protein - the prions - which cause diseases such as vCJD, are thought to be able to twist themselves into a shape which gives them the ability to "infect" nearby healthy tissue.
But until now it had not been thought that tau proteins had the same contagious property.
Dr Michel Goedert of the MRC Laboratory of Molecular Biology in Cambridge, worked on the study.
He said: "This opens new avenues in dementia research that will aim to understand how abnormal tau can spread.
"We can also investigate how diseases caused by tau aggregates and prions are similar."
Professor David Allsop, an expert in neuroscience at Lancaster University, said the study might help explain how tangles spread from one region of the brain to another during the course of Alzheimer's.
However, he said: "This does not mean that these diseases are infectious in the same way as mad cow disease and human CJD.
"There is no evidence that diseases like Alzheimer's disease and Parkinson's disease can be transmitted from one person to another."
Rebecca Wood, chief executive of the Alzheimer's Research Trust, said: "This greater understanding of how tangles spread in Alzheimer's may lead to new ways of stopping them and defeating the disease."
However, Dr Susanne Sorensen, head of research at the Alzheimer's Society, stressed that work was carried out in genetically modified mice, and there was a lot of work to be done before the implications were fully understood.
"There is still so much we do not understand about the changes in tau that lead to tangle formation in humans and, eventually, widespread brain cell death," she said.
Plaques and Tangles
© 2000 - 2009 American Health Assistance Foundation
The formation of amyloid plaques and neurofibrillary tangles are thought to contribute to the degradation of the neurons (nerve cells) in the brain and the subsequent symptoms of Alzheimer's disease.
One of the hallmarks of Alzheimer's disease is the accumulation of amyloid plaques between nerve cells (neurons) in the brain. Amyloid is a general term for protein fragments that the body produces normally. Beta amyloid is a protein fragment snipped from an amyloid precursor protein (APP). In a healthy brain, these protein fragments are broken down and eliminated. In Alzheimer's disease, the fragments accumulate to form hard, insoluble plaques.
Neurofibrillary tangles are insoluble twisted fibers found inside the brain's cells. These tangles consist primarily of a protein called tau, which forms part of a structure called a microtubule. The microtubule helps transport nutrients and other important substances from one part of the nerve cell to another. In Alzheimer's disease, however, the tau protein is abnormal and the microtubule structures collapse.
The following medical illustrations can provide you with more information:
- Anatomy of the Brain
- Brain with Alzheimer's Disease
- How the Brain and Nerve Cells Change During Alzheimer's
Last Reviewed On: 05/11/09
Remembering my friend Muriel (Look at my post in the archives in April)