In the news: Blood test progress for Alzheimer’s

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By Dr Laura Phipps | Monday 07 July 2014

In the news today is research by scientists at King’s College London and co-funded by Alzheimer’s Research UK – one of our largest grants to date. The team has discovered a protein ‘fingerprint’ in blood that could predict whether someone with mild memory problems may go on to develop Alzheimer’s.

Why do we need a blood test for Alzheimer’s?

Alzheimer’s disease can start to develop in the brain 10-15 years before symptoms show and that poses a huge challenge for researchers working hard to defeat it. By the time a diagnosis of Alzheimer’s is given, damage in the brain has already begun. Reversing this damage is a huge ask, but getting in early and preventing it is a real possibility.

The numbers are promising and suggest that the test could hold potential for predicting who may go on to develop Alzheimer’s

That’s why research into early detection is so key to progress in dementia research. If we can detect Alzheimer’s early and accurately, those affected can get involved in clinical trials and receive potential new treatments at a time when they are most likely to benefit. You can read more in our March blog post ‘What’s the point of a blood test for Alzheimer’s?’.

A blood test would be a simple way to predict those with early memory problems who are most likely to go on to develop the disease, but the science required to develop one is staggeringly complex.

Today’s new findings are another step towards these important goals. Let’s explore the research in more detail.

Today’s research

Whereas earlier efforts to develop blood tests to predict Alzheimer’s have focused on measuring levels of one or two culprit proteins in spinal fluid, focus is starting to shift towards panels of multiple proteins in  blood that may give a more robust signal and be easier to measure.

This study found 10 proteins which, when measured in people with early memory and thinking problems called mild cognitive impairment (MCI), were able to predict who would go on to develop Alzheimer’s within a year.

Not everyone with MCI will go on to develop Alzheimer’s but understanding which people are most likely to develop the disease and why is crucial. It helps researchers to understand the early stages of Alzheimer’s, as well as supporting people at high risk and providing them with the opportunity to take part in research.

Building on earlier work

If changes in our bodies are mirrored in our blood then it stands to reason that many aspects of our life could influence our blood ‘fingerprints’. Researchers have also found that factors as seemingly insignificant as the type of needle or vial used to collect blood samples could influence the results. Teasing apart real signals specific to Alzheimer’s from background noise presents a further challenge for researchers.

To overcome these barriers and make their findings as robust as possible, the team used blood samples from large studies across Europe and Canada, as well as those from King’s College London. This is a great example of how data sharing and collaboration is helping us to make progress in dementia research.

What does it mean for me?

The test outlined in today’s study can predict who will go on to develop Alzheimer’s with an accuracy of 87%, a sensitivity of 85% and a specificity of 88%. These figures are used to indicate the likelihood of the test wrongly predicting who may go on to develop Alzheimer’s, or missing those who would.

The numbers are promising and suggest that the test could hold potential for predicting who may go on to develop Alzheimer’s in people already presenting with early memory problems.

However, it is not being developed as a population screening tool. If you were to scale up this test to use on the general population, the risk of misdiagnosis would much higher. You can learn more about the statistics behind this here. Therefore while this research is an important step in the right direction, your doctor won’t be able to offer such a test at the moment. As Prof Lovestone says: “Our next step will be to test our findings in even larger sample sets, to further improve accuracy and reduce the risk of misdiagnosis, before we can develop a reliable test suitable to be used by doctors.”

What next?

While this study is already one of the largest to look at changes in blood in MCI, the results still need replicating in even larger groups, and this is next on the to-do list for the team.  They also need to build more streamlined technology for the measurement of the 10 proteins, to make the test easier to carry out in the lab. These are all important steps in the development process of any new test towards the clinic.

The ultimate aim is to develop a clinical tool that could help doctors to paint a clearer picture for people with mild cognitive impairment, as well as assisting in the design of clinical trials for new treatments. Today’s research takes us closer to this goal and highlights the importance of continued investment in research to make this hope a reality.

Last month, Alzheimer’s Research UK launched our £100m Defeat Dementia campaign, including initiatives such as the Dementia Consortium and our Global Clinical Development Fund. These initiatives will support researchers like Prof Lovestone in developing new detection techniques to the point where they can be used by doctors in the clinic and directly benefit people with memory problems.

Visit our award-winning dementia lab to find out more about research into dementia.

You can hear the research leader Prof Simon Lovestone, now at Oxford University, talk more about this important area of research on the Naked Neuroscience podcast.


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Dr Laura Phipps