Using Plasma Amyloid Beta Oligomer to Screen in Alzheimer’s Disease: A Pilot Study

Previous studies have shown that plasma amyloid-beta oligomers (AβOs), the toxic form of amyloid-beta (Aβ), are a critical issue in the development or worsening of Alzheimer's disease (AD) and can be regarded as a blood marker for screening in dementia. We examined plasma AβOs with their related biomarkers in a case-control study to clarify these issues. A total of 16 patients diagnosed with Alzheimer's dementia (AD) and 16 cognitively normal controls (NCs) were recruited to compare their plasma biomarkers, AβO, Aβ_1-40, and Aβ_1-42, also referring to other parameters like APOE ε4 status, Clinical Dementia Rating^®-Sum of Boxes (CDR^®-SB), and Mini Mental Status Examination (MMSE) scores. In plasma concentrations of Aβ_1-40, Aβ_1-42, and AβO, the mean concentrations were significantly different between the two groups. There is a significant increase in the concentrations of Aβ_1-40 and AβO, while Aβ_1-42 is decreased in individuals with AD compared to NC. AβO was statistically associated with the Aβ_1-40 and Aβ_1-42/Aβ_1-40 ratio. Higher plasma concentrations of AβO were significantly associated with AD compared to non-dementia controls. This suggests that AβOs can be potential plasma biomarkers to screen in AD. However, a study recruiting more individuals is necessary to examine the association, if any.