October 30, 2017

expert reaction to Alzheimer’s protein passing from blood to brain in mice

In a new study, published in Molecular Psychiatry, researchers investigate whether an Alzheimer’s protein can spread between mice that share a blood supply.

Prof. Tara Spires-Jones, UK Dementia Research Institute Programme Lead and Deputy Director, Centre for Discovery Brain Sciences, University of Edinburgh, said:

“There is no evidence that Alzheimer’s is a transmissible disease in people.  This study was scientifically interesting in that it shows in mice (6 mice per group) that one of the pathological proteins that builds up in Alzheimer’s brains can get into the brain from the blood stream over a period of many months of transfusion. This is important for our understanding of biological changes and how toxic proteins may spread through the body, but this is very far removed from human Alzheimer’s disease.  There are no human data to indicate that people should worry about catching Alzheimer’s from blood transfusions.”

Dr James Pickett, Head of Research at Alzheimer’s Society says:

“This animal study adds to previous evidence showing that is it possible for beta-amyloid – a protein implicated in Alzheimer’s – to pass from the blood into the brain, but it doesn’t tell us whether this process can cause Alzheimer’s disease.

“Seeing the transfer of beta-amyloid from the blood of a mouse into its brain in a highly artificial lab situation does not tell us that this happens in people in real life. Studies following people who have received blood transfusions from people who later developed Alzheimer’s disease find no evidence that the transfusion recipients are at an increased risk of developing Alzheimer’s disease themselves.

“We are still learning about the underlying causes of dementia and researchers should continue to investigate whether beta-amyloid in the blood plays any role in the development of Alzheimer’s. People should not be alarmed – even taking this study into account, there remains no evidence that you can ‘catch’ Alzheimer’s disease or that it can be passed on in blood transfusions.”

Dr David Reynolds, Chief Scientific Officer at Alzheimer’s Research UK, said:

“The brain does not operate in isolation from the rest of the body. While Alzheimer’s may specifically cause damage to the brain, it is important that we consider the whole of the body as we work to understand and tackle the disease.

“While scientists tend to think of the amyloid protein forming and building up in the brain, this study highlights the potential for amyloid from outside the brain to play a role in the disease. The research in mice suggests that prolonged periods with artificially high levels of amyloid in the blood could cause Alzheimer’s related changes in the brain. This is an interesting finding at a research level, which may help scientists unpick the interplay between amyloid in the brain and the rest of the body.

“As with any research involving mice, the only way to know if these findings are relevant to how Alzheimer’s develops in people is through studies that focus on human biology. If these findings do prove to be relevant to people, it highlights the continued importance of developing treatments that target amyloid in the body as well as the brain.”

“The mice involved in this study produced levels of amyloid that are much higher than what we’d see in people with Alzheimer’s disease, and rather than receiving a single blood transfusion, these mice shared a circulatory system for a whole year. There is no suggestion from this research that Alzheimer’s could be spread by blood transfusions in people. Last year an extensive study involving 1.4 million people who were followed up for many years, found no increased risk associated with receiving a transfusion from people with Alzheimer’s.”

* ‘Blood-derived amyloid-β protein induces Alzheimer’s disease pathologies’ by Bu et al. was published in Molecular Psychiatry at 20:00 UK time on Monday 30^th October: DOI: 10.1038/mp.2017.204. 

All our previous output on this subject can be seen at this weblink: http://www.sciencemediacentre.org/expert-reaction-to-evidence-for-human-transmission-of-amyloid-beta/

Declared interests

Prof. Spires-Jones: “I am employed by the University of Edinburgh and am a member of the Grant Review Board for Alzheimer’s Research UK.”

Others: None received