Risacher, Shannon L.Fandos, NoeliaRomero, JudithSherriff, IanPesini, PedroSaykin, Andrew J.Apostolova, Liana G.2019-10-092019-10-092019-07-26Risacher, S. L., Fandos, N., Romero, J., Sherriff, I., Pesini, P., Saykin, A. J., & Apostolova, L. G. (2019). Plasma amyloid beta levels are associated with cerebral amyloid and tau deposition. Alzheimer's & dementia (Amsterdam, Netherlands), 11, 510–519. doi:10.1016/j.dadm.2019.05.007https://hdl.handle.net/1805/21072Introduction: We investigated the relationship of plasma amyloid beta (Aβ) with cerebral deposition of Aβ and tau on positron emission tomography (PET). Methods: Forty-four participants (18 cognitively normal older adults [CN], 10 mild cognitive impairment, 16 Alzheimer's disease [AD]) underwent amyloid PET and a blood draw. Free and total plasma Aβ40 and Aβ42 were assessed using a validated assay. Thirty-seven participants (17 CN, 8 mild cognitive impairment, 12 AD) also underwent a [18F]flortaucipir scan. Scans were preprocessed by standard techniques, and mean global and regional amyloid and tau values were extracted. Free Aβ42/Aβ40 (Aβ F42:F40) and total Aβ42/Aβ40 (Aβ T42:T40) were evaluated for differences by diagnosis and relation to PET Aβ positivity. Relationships between these measures and cerebral Aβ and tau on both regional and voxel-wise basis were also evaluated. Results: Lower Aβ T42:T40 was associated with diagnosis and PET Aβ positivity. Lower plasma Aβ T42:T40 ratios predicted cerebral Aβ positivity, both across the full sample and in CN only. Finally, lower plasma Aβ T42:T40 ratios were associated with increased cortical Aβ and tau in AD-related regions on both regional and voxel-wise analyses. Discussion: Plasma Aβ measures may be useful biomarkers for predicting cerebral Aβ and tau. Additional studies in larger samples are warranted.en-USAttribution 4.0 United StatesBlood biomarkersAmyloid positron emission tomography (PET)Tau positron emission tomography (PET)Alzheimer's disease (AD)Mild cognitive impairment (MCI)Article