Plasma Aβ42/40 ratio alone or combined with FDG-PET can accurately predict amyloid-PET positivity: a cross-sectional analysis from the AB255 Study.

Background: To facilitate population screening and clinical trials of disease-modifying therapies for Alzheimer's disease, supportive biomarker information is necessary. This study was aimed to investigate the association of plasma amyloid-beta (Aβ) levels with the presence of pathological accumulation of Aβ in the brain measured by amyloid-PET. Both plasma Aβ42/40 ratio alone or combined with an FDG-PET-based biomarker of neurodegeneration were assessed as potential AD biomarkers.

Plasma Aβ42/40 Ratio Detects Early Stages of Alzheimer's Disease and Correlates with CSF and Neuroimaging Biomarkers in the AB255 Study.

Background: Easily accessible biomarkers are needed for the early identification of individuals at risk of developing Alzheimer's disease (AD) in large population screening strategies.

Objectives: This study evaluated the potential of plasma β-amyloid (Aβ) biomarkers in identifying early stages of AD and predicting cognitive decline over the following two years.

Design: Total plasma Aβ42/40 ratio (TP42/40) was determined in 83 cognitively normal individuals (CN) and 145 subjects with amnestic mild cognitive impairment (a-MCI) stratified by an FDG-PET AD-risk pattern.

Blood amyloid beta levels in healthy, mild cognitive impairment and Alzheimer's disease individuals: replication of diastolic blood pressure correlations and analysis of critical covariates.

Plasma amyloid beta (Aβ) levels are being investigated as potential biomarkers for Alzheimer's disease. In AB128 cross-sectional study, a number of medical relevant correlates of blood Aβ40 or Aβ42 were analyzed in 140 subjects (51 Alzheimer's disease patients, 53 healthy controls and 36 individuals diagnosed with mild cognitive impairment). We determined the association between multiple variables with Aβ40 and Aβ42 levels measured in three different blood compartments called i) Aβ directly accessible (DA) in the plasma, ii) Aβ recovered from the plasma matrix (RP) after diluting the plasma sample in a formulated buffer, and iii) associated with the remaining cellular pellet (CP).

Several direct and calculated biomarkers from the amyloid-β pool in blood are associated with an increased likelihood of suffering from mild cognitive impairment.

Validation of cost-effective, non-invasive methods to identify early (pre-clinical) Alzheimer's disease (AD) is increasingly becoming a key research challenge. We have developed two ELISA sandwich colorimetric tests for the accurate detection of amyloid-β (Aβ)1-40 and Aβ1-42: i) directly accessible (DA) in the plasma, ii) recovered from the plasma sample (RP) after diluting the plasma sample in a formulated buffer, and iii) associated with the remaining cellular pellet (CP). These tests were carried out on samples from healthy controls (n = 19) and individuals with mild cognitive impairment (MCI; n = 27) with amnestic-hippocampal syndrome to investigate whether this comprehensive approach may help to explain the association between blood Aβ levels and MCI.