Aging populations are anticipated to herald an increase in the number of people worldwide with Alzheimer’s disease – a neurodegenerative condition with increasing prevalence in old age. Even with the advent of high-definition neuroimaging technologies, such as computerized tomography (CT) and magnetic resonance imaging (MRI), the diagnosis of Alzheimer’s disease is still largely based on patient history and clinical observations. Although there is currently no cure for Alzheimer’s disease, early and accurate diagnosis resulting in timely treatment is thought to help slow its progress. Eckart Meese and Andreas Keller from Saarland University, Germany and colleagues present a novel biomarker for the disease based on detecting specific microRNA (miRNA) patterns in patient blood, as published in their recent study in Genome Biology. Meese and Keller told us more about these intriguing results and what impact they could have as a diagnostic marker for the disease.
What was your motivation for performing the study?
This research is mainly driven by the appreciation that miRNA is a rather stable component not only in serum but even more so in blood cells. Our study is conducted as part of a general endeavor towards the development of miRNA blood born biomarkers. Within this framework we set out to identify disease specific miRNA signatures.
What did you find most surprising about your results and what can we learn from this?
Most intriguing is the disease specificity of the miRNA pattern found in blood cells of patients. At this point of our research we are only at the beginning of a biological understanding of the miRNA pattern identified. Similarities in some elements of the miRNA pattern between Alzheimer’s disease patients and those with other neurological conditions, possibly reflect similar biological processes in the cells harboring the miRNAs. Knowing the identities of the miRNAs present in blood biomarkers will allow us to gain insight into aspects of the immunological response, at least for those cell types that contribute most of the miRNA signatures.
How close to the clinic do you believe miRNA blood biomarkers for Alzheimer’s disease are?
Our results make us confident that miRNA signatures can likely play a role in the future diagnosis of Alzheimer’s disease. Prior to clinical studies it is however important to clarify the biological role of the identified miRNAs and to determine to what extent the miRNA pattern reflects different stages of the disease.
Do you believe it will ever be possible to sufficiently partition an Alzheimer’s disease signature from other cohorts to make miRNA blood biomarkers the sole basis of diagnosis?
To answer this question we need to deepen our understanding of the biology of the blood born miRNA signature. Independent of the progress in our understanding of the function of miRNAs in blood cells, it is however likely that miRNA signatures will mostly play a role as companion diagnostics.
What’s next for your research?
Our primary near-term goal will be to address the question about the diagnostic potential of miRNAs as early biomarkers. Given the situation of Alzheimer’s as a progressive disease, it appears of foremost importance to identify those miRNA that indicate the disease in the early stages.
For more on the burden of Alzheimer’s disease and efforts underway to better manage and treat the disease, see our interview with Executive Director of Alzheimer’s Disease International, Marc Wortmann. To find out about the stability and variability of miRNA in blood, take a look at this study in BMC Genomics.
Questions from Naomi Attar (@naomiattar), Senior Editor for Genome Biology.