Citations

AbstractIntroductionWe examined and compared plasma phospho‐tau181 (pTau181) and total tau: (1) across the Alzheimer's disease (AD) clinical spectrum; (2) in relation to brain amyloid β (Aβ) positron emission tomography (PET), tau PET, and cortical thickness; and (3) as a screening tool for elevated brain Aβ.MethodsParticipants included 172 cognitively unimpaired, 57 mild cognitively impaired, and 40 AD dementia patients with concurrent Aβ PET (Pittsburgh compound B), tau PET (AV1451), magnetic resonance imaging, plasma total tau, and pTau181.ResultsPlasma total tau and pTau181 levels were higher in AD dementia patients than those in cognitively unimpaired. Plasma pTau181 was more strongly associated with both Aβ and tau PET. Plasma pTau181 was a more sensitive and specific predictor of elevated brain Aβ than total tau and was as good as, or better than, the combination of age and apolipoprotein E (APOE).DiscussionPlasma pTau181 may have utility as a biomarker of AD pathophysiology and as a noninvasive screener for elevated brain Aβ.

Abstract Introduction Tau protein levels in plasma may be a marker of neuronal damage. We examined associations between plasma tau levels and Alzheimer's disease (AD)–related magnetic resonance imaging (MRI) and positron emission tomography (PET) neuroimaging measures among nondemented individuals. Methods Participants included 378 cognitively normal (CN) and 161 mild cognitive impairment (MCI) individuals enrolled in the Mayo Clinic Study of Aging with concurrent neuropsychological measures and amyloid PET, fluorodeoxyglucose PET, and MRI. Baseline plasma tau levels were measured using the Quanterix Simoa‐HD1 tau assay. Results Plasma tau levels were higher in MCI compared with CN (4.34 vs. 4.14 pg/mL, P = .078). In regression models adjusted for age, gender, education, and APOE , higher plasma tau was associated with worse memory performance (b = −0.30, P = .02) and abnormal cortical thickness in an AD signature region (odds ratio = 1.80, P = .018). Discussion Plasma tau is associated with cortical thickness and memory performance. Longitudinal studies will better elucidate the associations between plasma tau, neurodegeneration, and cognition.