Researchers Move Closer to a Blood Test for Alzheimer’s Disease

Researchers are advancing toward a potential blood test for Alzheimer’s by examining circulating molecules known as miRNA.

A newly published study reveals that doctors are moving closer to a potential blood test for detecting Alzheimer’s disease.

Researchers in Germany have made new steps towards a potential blood test for Alzheimer’s by studying molecules called miRNA circulating in the blood. The research is published on 29 July in the journal Genome Biology.

Currently, a diagnosis of Alzheimer’s disease can only be confirmed post-mortem, and diagnosis during life is made based on the results of memory and thinking tests and brain scans. There is a growing focus on developing more sensitive methods of detection, to help improve the accuracy of diagnosis. This includes the search for changes in blood that could be translated into a clinically useful blood test to aid diagnosis of the disease.

To investigate this further, the team studied molecules called miRNA, which play a role in fine-tuning the activity of genes in the body. miRNA have already been linked to diseases such as cancer and heart disease and research is underway to investigate their role in Alzheimer’s.

The team analyzed blood samples from 48 people with Alzheimer’s and 22 unaffected controls, looking for changes in the levels of miRNA between the two groups. They discovered 140 miRNAs whose levels were altered in people with Alzheimer’s and 12 of these were made into a ‘panel’ for further testing. The 12 miRNA’s were thought to regulate the activity of more than 2000 genes, including genes responsible for nerve cell development and the projection of nerve cells across the brain.

The panel was used to test another 202 blood samples, taken from volunteers with and without Alzheimer’s, those with early memory and thinking problems called mild cognitive impairment, and also those with other neurological conditions including multiple sclerosis, Parkinson’s, and schizophrenia.

The research shows that the panel was able to distinguish between those with and without Alzheimer’s with a high degree of accuracy, although the ability to distinguish between Alzheimer’s and other neurological conditions was lower.

Dr Eric Karran, Director of Research at Alzheimer’s Research UK, the UK’s leading dementia research charity, said:

“This is an interesting approach to studying changes in blood in Alzheimer’s and suggests that miRNAs could be playing a role in the disease. The findings highlight the importance of continuing research efforts to understand the contribution of miRNAs to Alzheimer’s, but the translation of this into a blood test for Alzheimer’s in the clinic is still some way off.

“A blood test to help detect Alzheimer’s could be a useful addition to a doctor’s diagnostic armory, but such a test must be well validated before it’s considered for use. We need to see these findings confirmed in larger samples and more work is needed to improve the test’s ability to distinguish Alzheimer’s from other neurological conditions.

“An accurate diagnosis of Alzheimer’s is important to allow people access to appropriate treatments, support, and information, as well as the opportunity to get involved with research. Alzheimer’s Research UK is currently funding research looking into miRNAs in Alzheimer’s and sustained funding for research like this is vital to make progress for people with this devastating disease.”

Learn more about developing blood tests for Alzheimer’s by visiting our virtual dementia lab.

Reference: “A blood based 12-miRNA signature of Alzheimer disease patients” by Petra Leidinger, Christina Backes, Stephanie Deutscher, Katja Schmitt, Sabine C Mueller, Karen Frese, Jan Haas, Klemens Ruprecht, Friedemann Paul, Cord Stähler, Christoph JG Lang, Benjamin Meder, Tamas Bartfai, Eckart Meese and Andreas Keller, 29 July 2013, Genome Biology.
DOI: 10.1186/gb-2013-14-7-r78