A blood test for Alzheimer’s based on fluorescence spectroscopy
University of Calgary
Alzheimer’s disease is a devastating condition that is reaching epidemic proportions as the population ages. Despite enormous research effort, currently there are no truly effective treatments and no cure. One possible reason for repeated failures with new drugs is that treatment is started too late in the course of the disease, after significant brain damage has already accumulated. Given the lack of reliable non-invasive diagnostic tests that can detect the disease early, patients are enrolled in trials only after dementia is clinically apparent, possibly at a stage where therapeutic effectiveness is already reduced. The goal of this project is to develop a blood test to diagnose the earliest stages of Alzheimer’s, possibly even before clinical dementia is apparent. We use special molecular probes and advanced spectral microscopy to detect minute amounts of abnormal proteins in blood that accumulate even in the early stages. The hope is that this approach will help diagnose Alzheimer’s with greater certainty, monitor its progression or track the efficacy of new treatments. This test may eventually be deployed to screen the population at large for future risk of Alzheimer’s so that treatment can be started before disease sets in, much as we now do with cholesterol testing for vascular disease.
Relevance to the acceleration of therapeutics for neurodegenerative diseases of aging
Researchers are beginning to realize that trying to treat Alzheimer’s once dementia is already apparent, may be too late; the best hope for new drugs is to start treatment early, possibly even before any signs of dementia. The problem is then how do you identify patients who are still healthy, but who are destined to develop Alzheimer’s in coming years? Our hope is that the test we are working on will identify Alzheimer’s at the earliest stages: this will maximize chances of developing and successfully testing new drugs, and once these are available, we can identify patients at risk using our test so that new drug therapy can be started early to maximize effectiveness.
We expect to learn how our detection methods interact with the earliest abnormalities that show up in blood of Alzheimer’s patients. This will in turn guide further refinements of our technique so it becomes more and more sensitive for picking up early disease, even in healthy people who are at risk of developing the disease years later.
At the conclusion of this project, we have shown that white blood cells do carry spectral information that can detect early Alzheimer’s. During the course of the project, we observed that red blood cells are also capable of reporting such early disease. Although work on white cells continues, the focus has shifted to red cells because these are far more plentiful in blood and do not require special isolation procedures: whole blood can be used. Our most recent data indicate that spectral detection from red cells may be as reliable. We now have a cohort of over 100 subjects (controls, mild cognitive impairment and Alzheimer’s) where this prediction appears to be valid.