Plasma oligomer beta-amyloid is associated with disease severity and cerebral amyloid deposition in Alzheimer's disease spectrum

BackgroundMultimer detection system-oligomeric amyloid-beta (MDS-OA beta) is a measure of plasma OA beta, which is associated with Alzheimer's disease (AD) pathology. However, the relationship between MDS-OA beta and disease severity of AD is not clear. We aimed to investigate MDS-OA beta levels in different stages of AD and analyze the association between MDS-OA beta and cerebral A beta deposition, cognitive function, and cortical thickness in subjects within the AD continuum.MethodsIn this cross-sectional study, we analyzed a total 126 participants who underwent plasma MDS-OA beta, structural magnetic resonance image of brain, and neurocognitive measures using Korean version of the Consortium to Establish a Registry for Alzheimer's Disease, and cerebral A beta deposition or amyloid positron emission tomography (A-PET) assessed by [18F] flutemetamol PET. Subjects were divided into 4 groups: N = 39 for normal control (NC), N = 31 for A-PET-negative mild cognitive impairment (MCI) patients, N = 30 for A-PET-positive MCI patients, and N = 22 for AD dementia patients. The severity of cerebral A beta deposition was expressed as standard uptake value ratio (SUVR).ResultsCompared to the NC (0.803 +/- 0.27), MDS-OA beta level was higher in the A-PET-negative MCI group (0.946 +/- 0.137) and highest in the A-PET-positive MCI group (1.07 +/- 0.17). MDS-OA beta level in the AD dementia group was higher than in the NC, but it fell to that of the A-PET-negative MCI group level (0.958 +/- 0.103). There were negative associations between MDS-OA beta and cognitive function and both global and regional cerebral A beta deposition (SUVR). Cortical thickness of the left fusiform gyrus showed a negative association with MDS-OA beta when we excluded the AD dementia group.ConclusionsThese findings suggest that MDS-OA beta is not only associated with neurocognitive staging, but also with cerebral A beta burden in patients along the AD continuum.