The only definitive way to diagnose Alzheimer’s disease was the most invasive procedure imaginable: a post mortem analysis of brain tissue. Now, thanks to a new study conducted at the Research Institute of the McGill University Health Centre (RI-MUHC), it may be possible to diagnose the insidious disease using a simple blood test.
The study, published in the May 2011 issue of the Journal of Alzheimer’s Disease, focuses on a brain hormone called dehydroepiandrosterone (DHEA). The researchers were able to use oxidation to promote DHEA production in blood samples taken from people who do not have Alzheimer’s. The same procedure, when performed on people suffering from the disease, did not result in increased DHEA levels. The correlation was clear, says senior author and RIMUHC director Vassilios Papadopoulos. (The other authors are Georges Rammouz and Laurent Lecanu, also of the RI-MUHC, and Dr. Paul Aisen of the University of California at San Diego.)
“We demonstrated we could accurately and repetitively detect Alzheimer’s disease, with small samples of blood,” says Papadopoulos. “This test also allowed for differential diagnosis of early stages of Alzheimer’s disease, suggesting this can be used as a test to diagnose the disease in its infancy.” He believes the test may also be used to distinguish Alzheimer’s dementia from other cognitive impairments.
There are several disease-modifying therapies at the clinical trial stage but, as with any therapy, successful implementation depends on a reliable diagnosis. Currently, the diagnosis of Alzheimer’s follows the sequence of family history, information, mental assessment and the physical exam, focusing on neurological signs. A more definitive diagnosis, such as that promised by this new blood test, would be a welcome tool in the fight against Alzheimer’s.
“An accurate, easy and specific non-invasive biochemical test that correlates with clinical findings is vital,” says Papadopoulos. “We believe our results demonstrate that the DHEA-oxidation blood test can be used to diagnose Alzheimer’s at a very early stage and monitor the effect of therapies and the evolution of the disease.”
This research was funded by the National Institutes of Health and Samaritan Pharmaceuticals. The Research Institute of the McGill University Health Centre supports over 600 researchers, and over 1,000 graduate students, post-docs and fellows devoted to a broad spectrum of fundamental and clinical research.