CLASSICAL ALZHEIMER’S DISEASE BIOMARKERS IN PLASMA. CURRENT STATUS

Abstract

Cerebrospinal fuid (CSF) levels of amyloid peptide Aβ, phospho-tau protein and total tau protein are currently considered as the 3 established (core) biomarkers for Alzheimer’s disease (AD). They have been incorporated in various diagnostic criteria as a useful tool in the (differential) diagnosis of AD. Assessment of the same biomarkers in plasma does not require the relatively invasive lumbar puncture and allows sampling in the community, storing of larger quantities of plasma, testing a larger spectrum of analytes and repeated testing when this is considered necessary for follow up and for marginal or conflicting results. Data so far indicate that plasma phospho-tau (τ ) offers a high diagnostic value, similar to that of CSF τP-181,,with a very good discrimination between AD and other dementia disorders. Plasma amyloid, in the form of the Αβ42/Αβ40 ratio, seems to be very good predictor of brain amyloid burden and offers a useful screening tool and a good substitute of amyloid positron emission tomography. The above data are encouraging; however, further studies are needed for optimization of assessment methods for plasma biomarkers, optimization of their diagnostic value and for widespread availability in every day practice.