Alzheimer defect can be 'passed from one brain to another'

Published on Sunday 7 June 2009 22:07

HARMFUL "tangles" of protein linked to Alzheimer's disease can be transmitted from one brain to another, scientists have discovered.

Healthy mice injected with brain tissue from affected animals went on to develop the same defect themselves.

Destructive knots of protein fibres called tau tangles were seen to spread through the brains of the injected mice.

Experts pointed to similarities with variant CJD – the human form of mad cow disease. But they were at pains to stress there was no evidence that Alzheimer's was contagious and could be "caught", for instance, through blood transfusions.

Tau tangles, one of two protein abnormalities found in Alzheimer's patients, form inside nerve cells and kill them. A feature of a number of neurodegenerative disorders, they were first described in 1907 by Dr Alois Alzheimer, the German physician who identified Alzheimer's disease.

Two populations of genetically modified "humanised" mice were used for the new research conducted by UK, German and Swiss scientists.

One group had a gene that caused them to generate harmful human tau tangles in their brains. Diluted brain extract from these mice was injected into the brains of other mice with a normal healthy version of human tau protein.

The transferred material caused tau tangles to spring up at the injection sites and spread out to other parts of the brain.

Reporting their findings online in the journal Nature Cell Biology, the scientists wrote: "The present findings demonstrate transmission of tauopathy between transgenic mouse lines."

But study leader Dr Michel Goedert, from the Medical Research Council laboratory of molecular biology in Cambridge, made it clear there was no suggestion that Alzheimer's tau protein was infectious.