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

ABSTRACT

BACKGROUND: Multimer detection system-oligomeric amyloid-ß (MDS-OAß) is a measure of plasma OAß, which is associated with Alzheimer's disease (AD) pathology. However, the relationship between MDS-OAß and disease severity of AD is not clear. We aimed to investigate MDS-OAß levels in different stages of AD and analyze the association between MDS-OAß and cerebral Aß deposition, cognitive function, and cortical thickness in subjects within the AD continuum. METHODS: In this cross-sectional study, we analyzed a total 126 participants who underwent plasma MDS-OAß, 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 Aß 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 Aß deposition was expressed as standard uptake value ratio (SUVR). RESULTS: Compared to the NC (0.803 ± 0.27), MDS-OAß 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-OAß 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-OAß and cognitive function and both global and regional cerebral Aß deposition (SUVR). Cortical thickness of the left fusiform gyrus showed a negative association with MDS-OAß when we excluded the AD dementia group. CONCLUSIONS: These findings suggest that MDS-OAß is not only associated with neurocognitive staging, but also with cerebral Aß burden in patients along the AD continuum.