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Mice respond well to ‘Alzheimer’s vaccine’

Thursday 23 August 2007

A vaccine that could ease the suffering caused by Alzheimer’s disease has been developed, the Daily Mail reported.

The newspaper said that when a vaccine was used on mice with a ‘dementia-like’ illness, the symptoms of Alzheimer’s worsened at a slower rate than in unvaccinated mice. A human vaccine is still a decade away from market, the newspaper continued.

The research behind the report is an animal study that investigated the possibility of using the body’s immune system to prevent the formation of ‘tangles’ in the brain linked with the symptoms of Alzheimer’s disease.

It would be wrong to assume that the treatment used in this study is guaranteed to reach the stage where it can be tested in humans. Also, it is not known whether it will show the same effects in humans as it does in mice. Although the results are interesting, we are at a very early stage in the testing process and further research is needed before we will know whether such therapy can be of use to people.

Where did the story come from?

Doctor Ayodeji A. Asuni and colleagues from the New York University School of Medicine carried out this research. The study was funded by the National Institute of Health and by the Alzheimer’s Association. The study was published in the peer-reviewed medical journal, The Journal of Neuroscience .

What kind of scientific study was this?

This was a study in mice specially bred to show symptoms similar to those seen in Alzheimer’s sufferers. The mice had ‘brain tangles’, which are abnormal tangles of brain fibres.

Brain tangles are known to be a feature of Alzheimer’s disease in humans, and which may be responsible for the cognitive and functional symptoms of the disease. Functional symptoms of Alzheimer's disease typically include movement and coordination problems, while cognitive symptoms include disruptions in memory, thinking, reasoning and language.

Brain tangles are also a feature of frontotemporal dementia (also known as Pick’s disease; a form of dementia characterised by behaviour and personality change). The researchers also considered this in their study.

The researchers developed a chemical aimed at encouraging the mice’s own immune systems to generate antibodies that could attack the ‘brain tangles’, thereby reducing the functional and cognitive symptoms associated with these.

What were the results of the study?

The researchers found that in the immunised mice there was reduced brain tangling and improved physical functioning compared to those who were given the control. Cognition was no different between the groups.

What interpretations did the researchers draw from these results?

The researchers conclude that the new substance was able to clear brain tangles and that the present findings “may lead to a novel therapy targeting one of the major hallmarks of Alzheimer’s disease and frontotemporal dementia”.

What does the NHS Knowledge Service make of this study?

This is an interesting study further exploring potential treatments for neurodegenerative diseases. Importantly however, as the study is conducted in mice, it is too early to say how this research may be used to treat or prevent human disease. The following points should be taken into account:

  • The authors themselves admit that using, “this model [i.e. the specially bred mice] is not ideal for Alzheimer’s Disease”. While the engineered mice displayed genetic changes known to be found in frontotemporal dementia, the researchers admit that “to date, no [such] mutations have been observed in Alzheimer’s disease”.
  • The benefits of treatment in terms of effect on physical functioning diminished as the impairments advanced.
  • Although the news reports mention this as offering a potential treatment to ease the  “torment” and “devastating symptoms” of Alzheimer’s disease, this study mainly focused on physical functioning in mice. The researchers were unable to conduct in-depth tests into the effects on cognition. Problems with coordination and carrying out normal daily tasks are only one element of the disease spectrum of Alzheimer’s in humans; other effects, such as loss of memory, difficulty with speech and language, and problems with facial recognition, may be considered by many to be the most devastating part of the disease.

A potential vaccine for Alzheimer’s disease in humans is a long way off. Many studies in animals never make it to human testing and we must consider this study in that context. The findings however, are interesting and they pave the way for further studies that will improve our understanding of the potential for using immunotherapy to treat brain diseases.

Sir Muir Gray says...

Many advances in treatment have come from animal studies, but it is not possible to say if this will be one of them.

Analysis by Bazian
Edited by NHS Website

Links to the headlines

Scientists develop vaccine that could ease Alzheimer's torment.

Daily Mail, 21 August 2007

Links to the science

Asuni A, Boutajangout A, Quartermain D, et al.

Immunotherapy Targeting Pathological Tau Conformers in a Tangle Mouse Model Reduces Brain Pathology with Associated Functional Improvements.

J Neurosci 2007; 27:9115-9129