Collaborating scientists from Emory University School of Medicine, University of Pennsylvania, and Washington University have identified variations in the levels of 4 blood proteins that may enable early diagnosis of Alzheimer's.
In the study just published in Neurology, the researchers looked at variations of 190 proteins in the blood in 600 individuals that were either healthy, had been diagnosed with Alzheimer's disease, or showed signs of mild cognitive impairment. In this part of the study, they found 17 proteins that often displayed variant levels between the healthy patients and those diagnosed Alzheimer's or cognitive impairment.
The researchers then followed up by evaluating these 17 proteins in an additional 566 people participating in the multicenter Alzheimer's Disease Neuroimaging Initiative and found that 4 of the blood proteins consistently showed altered levels in these patients. The changes in the levels of these four proteins also correlated with the level of the beta-amyloid peptide in cerebrospinal fluid, which has previously been shown to be an indicator of Alzheimer's. The beta-amyloid peptide is what produces the brain plaques the lead to cognitive deterioration in Alzheimer's patients.
If the findings hold up, it could become the basis for the first blood test for Alzheimer's. At present, the only approved diagnostic test available for this disease is a costly and inconvenient PET brain scan. Also, as mentioned above, an analysis of a spinal fluid retrieved by a somewhat painful spinal tap has been shown to be an early marker of Alzheimer's.
However, a simple blood test that could done during a routine visit to the doctor would be much easier, enabling earlier diagnosis and treatment of more afflicted patients. While there is still no cure, early treatment of Alzheimer's can slow the progression and delay onset of the severe later stages of the disease.