In a National Institute on Aging-supported study released this week, Alzheimer's researchers found that levels of the protein apolipoprotein E in blood samples were strongly associated with levels of beta-amyloid deposits in the brain.
Because increased deposits of beta-amyloid are considered a hallmark of Alzheimer's, this link suggests that ApoE could be used as a blood-based protein biomarker for the disease.
In the study, which appeared in the online version of the Journal of Alzheimer's Disease in October and in this month's print edition, a team led by NIA scientist Madhav Thambisetty used mass spec to analyze the blood samples of 57 older, symptom-free subjects and compared those analyses to brain amyloid measurements of the same subjects taken via PET scans. The results demonstrated a strong correlation between the levels of amyloid plaques and levels of ApoE.
In a statement, Thambisetty said he now plans to test the results in serial blood samples collected from participants in the NIA's Baltimore Longitudinal Study of Aging to investigate how changing blood levels of ApoE may relate to pathological changes in the brain over time.
“If the results are equally positive, we may be able to develop a blood test that provides a less invasive, inexpensive method that helps to detect the early pathological changes of Alzheimer's disease,” he said.
This is not the only study to have examined a link between Alzheimer's disease and ApoE. The APOE gene, which makes the protein, is a known genetic risk factor for late-onset Alzheimer's. The protein was also one of the proteins examined as part of the Alzheimer's Disease Neuroimaging Initiative's effort to identify blood-based biomarkers for the disease. Results from that work were released earlier this month and are currently undergoing analysis (PM 12/10/2010).