June 7, 2009

experts comment on new research into Alzheimer’s as published in Nature Cell Biology

Scientists have shown how the protein tangles in the brain that cause Alzheimer’s disease can spread within the brain – this was shown by injecting affected brain tissue from one mouse brain to another, and observing the development of tangles in the recipient mice. The researchers stressed that this does not mean that Alzheimer’s is contagious.

Dr Susanne Sorensen, Head of Research, Alzheimer’s Society, said:

“The observation that tangle formation can be transferred from one type of trans genetic mouse line to another is certainly exciting and may change the way we think about tangle formation in diseases such as Alzheimer’s.

“However, the research was carried out using two different trans genetic mouse lines and we will need a lot more research before we understand the implications of these observations.

“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. Each new piece of knowledge helps build a better picture and takes us closer to the point where we can stop loss of brain tissue and dementia for good.”

Prof David Allsop, Professor of Neuroscience, Lancaster University, said:

“This paper shows that if you inject a brain extract made from a mouse with ‘tangles’ into another mouse without them, then tangle formation can be induced in the recipient mouse, and the tangles then spread to other brain regions away from the site of the injection.

“This is interesting because it could explain how tangles spread from one region of the brain to another during the course of Alzheimer’s disease and some other ‘tangle’ diseases. However, 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.

“Abnormal tangles build up in the brain during Alzheimer’s and other diseases of the brain. It’s not clear how that happens – but it is clear that Alzheimer’s itself is not contagious.

“We desperately need more research like this to find answers to dementia, a cruel condition that affects 700,000 people in the UK.”

The paper’s co-author, Dr Michel Goedert of the MRC Laboratory of Molecular Biology in Cambridge, whose work was funded by the Alzheimer’s Research Trust, said:

“We have looked at whether tau tangles can spread in mice. The injection of brain extract from tangle-bearing mice into animals without tangles caused their tau to tangle, and spread from the sites of injection to neighbouring brain regions. 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.”