scholarly journals Optimal Combinations of AT(N) Biomarkers to Determine Longitudinal Cognition in the Alzheimer's Disease

2021 ◽  
Vol 13 ◽  
Author(s):  
Rong-Rong Lin ◽  
Yan-Yan Xue ◽  
Xiao-Yan Li ◽  
Yi-He Chen ◽  
Qing-Qing Tao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cortical Thickness ◽  
Clinical Manifestations ◽  
Cognitive Status ◽  
Youden Index ◽  
Amyloid Pet ◽  
Cognitive Changes ◽  
Neurofilament Light ◽  
Tau Pet

Background: National Institute on Aging—Alzheimer's Association (NIA-AA) proposed the AT(N) system based on β-amyloid deposition, pathologic tau, and neurodegeneration, which considered the definition of Alzheimer's disease (AD) as a biological construct. However, the associations between different AT(N) combinations and cognitive progression have been poorly explored systematically. The aim of this study is to compare different AT(N) combinations using recognized biomarkers within the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort.Methods: A total of 341 participants were classified into cognitively unimpaired (CU; n = 200) and cognitively impaired (CI; n = 141) groups according to the clinical manifestations and neuropsychological tests. Cerebrospinal fluid (CSF) Aβ42 and amyloid-PET ([18F]flutemetamol) were used as biomarkers for A; CSF phosphorylated tau (p-tau) and tau-PET ([18F]flortaucipir) were used as biomarkers for T; CSF total tau (t-tau), hippocampal volume, temporal cortical thickness, [18F]fluorodeoxyglucose (FDG) PET, and plasma neurofilament light (NfL) were used as biomarkers for (N). Binary biomarkers were obtained from the Youden index and publicly available cutoffs. Prevalence of AT(N) categories was compared between different biomarkers within the group using related independent sample non-parametric test. The relationship between AT(N) combinations and 12-year longitudinal cognition was assessed using linear mixed-effects modeling.Results: Among the CU participants, A–T–(N)– was most common. More T+ were detected using p-tau than tau PET (p < 0.05), and more (N)+ were observed using fluid biomarkers (p < 0.001). A+T+(N)+ was more common in the CI group. Tau PET combined with cortical thickness best predicted cognitive changes in the CI group and MRI predicted changes in the CU group.Conclusions: These findings suggest that optimal AT(N) combinations to determine longitudinal cognition differ by cognitive status. Different biomarkers within a specific component for defining AT(N) cannot be used identically. Furthermore, different strategies for discontinuous biomarkers will be an important area for future studies.

scholarly journals Optimal Combinations of Biomarkers to Determine AT(N) in the Alzheimer’s Disease 

2020 ◽  
Author(s):  
Rong-Rong Lin ◽  
Yan-Yan Xue ◽  
Xiao-Yan Li ◽  
Yi-He Chen ◽  
Qing-Qing Tao ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Cortical Thickness ◽  
Clinical Stage ◽  
Youden Index ◽  
Amyloid Pet ◽  
Clinical Dementia Rating ◽  
Cognitive Changes ◽  
Neurofilament Light ◽  
Tau Pet

Abstract Background: National Institute on Aging—Alzheimer’s Association (NIA-AA) proposed the AT(N) system based on β-amyloid deposition, pathologic tau, and neurodegeneration, which considered the definition of Alzheimer’s disease (AD) as a biological construct. However, the associations between different AT(N) combinations and clinical stage and progression have been poorly explored systematically. The aim of this study is to compare different AT(N) combinations using recognized biomarkers within the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort.Methods: A total of 341 participants from ADNI cohort were classified into AT(N) groups, including 200 cognitively unimpaired (CU) participants and 141 cognitively impaired (CI) participants (101 mild cognitive impairment [MCI] and 40 Alzheimer’s disease [AD]). CSF Aβ42 and amyloid-PET ([18F]flutemetamol) were used as biomarkers for A; CSF phosphorylated tau (p-tau) and tau-PET ([18F]flortaucipir) were used as biomarkers for T; CSF total tau (t-tau), FDG-PET, hippocampal volume, temporal cortical thickness and plasma neurofilament light (NfL) were used as biomarkers for (N). Binarization of biomarkers was acquired from Youden index and public cutoffs. The relationship between different AT(N) biomarkers combinations and cognitive changes (longitudinal Mini-Mental State Examination scores and Clinical Dementia Rating Sum of Boxes) was examined using linear mixed modeling and coefficient of variation.Results: Among CU participants, A−T−(N)− variants were most common. More T+ cases were shown using p-tau than tau PET, and more N+ cases were shown using fluid biomarkers than neuroimaging. Among CI participants, A+T+(N)+ was more common. Tau PET combined with cortical thickness best predicted longitudinal cognitive decline in CI and MRI measurements in CU participants. Conclusion: These findings suggest that optimal combinations of biomarkers to determine AT(N) are differed by clinical stage. Different biomarkers within a specific component for defining AT(N) cannot be used identically. Furthermore, different strategies for discontinuous biomarkers will be an important area for the future studies.

scholarly journals Plasma tau and neurofilament light in frontotemporal lobar degeneration and Alzheimer's disease

Neurology ◽  
2020 ◽  
pp. 10.1212/WNL.0000000000011226
Author(s):  
Ignacio Illán-Gala ◽  
Alberto Lleo ◽  
Anna Karydas ◽  
Adam M. Staffaroni ◽  
Henrik Zetterberg ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Disease Severity ◽  
Cortical Thickness ◽  
Frontotemporal Lobar Degeneration ◽  
Amyloid Pet ◽  
Class Iii ◽  
Neurofilament Light Chain ◽  
Neurofilament Light ◽  
T Tau

ObjectiveTo test the hypothesis that plasma total tau (t-tau) and neurofilament light chain (NfL) concentrations may have a differential role in the study of frontotemporal lobar degeneration syndromes (FTLD-S) and clinically-diagnosed Alzheimer's disease (AD-S), we determined their diagnostic and prognostic value in FTLD-S and AD-S and their sensitivity to pathologic diagnoses.MethodsWe measured plasma t-tau and NfL with the Simoa platform in 265 participants: 167 FTLD-S, 43 AD-S, and 55 healthy controls (HC), including 82 pathology-proven cases (50 FTLD-Tau, 18 FTLD-TDP, 2 FTLD-FUS, and 12 AD) and 98 participants with amyloid PET. We compared cross-sectional and longitudinal biomarker concentrations between groups, their correlation with clinical measures of disease severity, progression and survival and cortical thickness.ResultsPlasma NfL, but not plasma t-tau discriminated FTLD-S from HC and AD-S from HC. Both plasma NfL and t-tau were poor discriminators between FLTD-S and AD-S. In pathology confirmed cases, plasma NfL was higher in FTLD than AD and in FTLD-TDP compared to FTLD-Tau, after accounting for age and disease severity. Plasma NfL, but not plasma t-tau, predicted clinical decline and survival and correlated with regional cortical thickness in both FTLD-S and AD-S. The combination of plasma NfL with plasma t-tau did not outperform plasma NfL alone.ConclusionsPlasma NfL is superior to plasma t-tau for the diagnosis and prediction of clinical progression of FTLD-S and AD-S.Classification of evidenceThis study provides Class III evidence that plasma NfL has superior diagnostic and prognostic performance than plasma t-tau in FTLD and AD.

scholarly journals Soluble P-tau217 reflects amyloid and tau pathology and mediates the association of amyloid with tau

2021 ◽  
Author(s):  
Niklas Mattsson-Carlgren ◽  
Shorena Janelidze ◽  
Randall Bateman ◽  
Ruben Smith ◽  
Erik Stomrud ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Medial Temporal Lobe ◽  
Amyloid Plaques ◽  
Amyloid Plaque ◽  
Amyloid Pet ◽  
Tau Pathology ◽  
Β Amyloid ◽  
Tau Pet ◽  
Disease Stages

Abstract Alzheimer’s disease is characterized by β-amyloid plaques and tau tangles. Plasma levels of phospho-tau217 (P-tau217) accurately differentiate Alzheimer’s disease dementia from other dementias, but it is unclear to what degree this reflects β-amyloid plaque accumulation, tau tangle accumulation, or both. In a cohort with post-mortem neuropathological data (N=88), both plaque and tangle density contributed independently to higher P-tau217. Several findings were replicated in a cohort with PET imaging (“BioFINDER-2”, N=426), where β-amyloid and tau PET were independently associated to P-tau217. P-tau217 correlated with β-amyloid PET (but not tau PET) in early disease stages, and with both β-amyloid and (more strongly) tau PET in late disease stages. Finally, P-tau217 mediated the association between β-amyloid and tau in both cohorts, especially for tau outside of the medial temporal lobe. These findings support the hypothesis that plasma P-tau217 is increased by both β-amyloid plaques and tau tangles and is congruent with the hypothesis that P-tau is involved in β-amyloid-dependent formation of neocortical tau tangles.

scholarly journals Aβ deposition is associated with increases in soluble and phosphorylated tau that precede a positive Tau PET in Alzheimer’s disease

2020 ◽  
Vol 6 (16) ◽  
pp. eaaz2387 ◽  
Author(s):  
Niklas Mattsson-Carlgren ◽  
Emelie Andersson ◽  
Shorena Janelidze ◽  
Rik Ossenkoppele ◽  
Philip Insel ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Pet ◽  
Phosphorylated Tau ◽  
Positron Emission ◽  
Aβ Aggregation ◽  
Tau Pet ◽  
5Xfad Mice ◽  
Tau Aggregation ◽  
T Tau

The links between β-amyloid (Aβ) and tau in Alzheimer’s disease are unclear. Cognitively unimpaired persons with signs of Aβ pathology had increased cerebrospinal fluid (CSF) phosphorylated tau (P-tau181 and P-tau217) and total-tau (T-tau), which increased over time, despite no detection of insoluble tau aggregates [normal Tau positron emission tomography (PET)]. CSF P-tau and T-tau started to increase before the threshold for Amyloid PET positivity, while Tau PET started to increase after Amyloid PET positivity. Effects of Amyloid PET on Tau PET were mediated by CSF P-tau, and high CSF P-tau predicted increased Tau PET rates. Individuals with MAPT mutations and signs of tau deposition (but without Aβ pathology) had normal CSF P-tau levels. In 5xFAD mice, CSF tau increased when Aβ aggregation started. These results show that Aβ pathology may induce changes in soluble tau release and phosphorylation, which is followed by tau aggregation several years later in humans.

scholarly journals Prospective longitudinal atrophy in Alzheimer’s disease correlates with the intensity and topography of baseline tau-PET

2020 ◽  
Vol 12 (524) ◽  
pp. eaau5732 ◽  
Author(s):  
Renaud La Joie ◽  
Adrienne V. Visani ◽  
Suzanne L. Baker ◽  
Jesse A. Brown ◽  
Viktoriya Bourakova ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Amyloid Pet ◽  
Specific Distribution ◽  
Positron Emission ◽  
Pet Radiotracers ◽  
Β Amyloid ◽  
Tau Pet ◽  
Prospective Longitudinal

β-Amyloid plaques and tau-containing neurofibrillary tangles are the two neuropathological hallmarks of Alzheimer’s disease (AD) and are thought to play crucial roles in a neurodegenerative cascade leading to dementia. Both lesions can now be visualized in vivo using positron emission tomography (PET) radiotracers, opening new opportunities to study disease mechanisms and improve patients’ diagnostic and prognostic evaluation. In a group of 32 patients at early symptomatic AD stages, we tested whether β-amyloid and tau-PET could predict subsequent brain atrophy measured using longitudinal magnetic resonance imaging acquired at the time of PET and 15 months later. Quantitative analyses showed that the global intensity of tau-PET, but not β-amyloid–PET, signal predicted the rate of subsequent atrophy, independent of baseline cortical thickness. Additional investigations demonstrated that the specific distribution of tau-PET signal was a strong indicator of the topography of future atrophy at the single patient level and that the relationship between baseline tau-PET and subsequent atrophy was particularly strong in younger patients. These data support disease models in which tau pathology is a major driver of local neurodegeneration and highlight the relevance of tau-PET as a precision medicine tool to help predict individual patient’s progression and design future clinical trials.

IC-P-156: Baseline amyloid PET imaging, longitudinal amyloid accumulation, and Tau PET imaging in preclinical Alzheimer's disease

2015 ◽  
Vol 11 (7S_Part_2) ◽  
pp. P105-P105
Author(s):  
Aaron P. Schultz ◽  
Elizabeth C. Mormino ◽  
Jasmeer P. Chhatwal ◽  
Molly LaPoint ◽  
Alex S. Dagley ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Pet Imaging ◽  
Amyloid Pet ◽  
Preclinical Alzheimer’S Disease ◽  
Amyloid Accumulation ◽  
Tau Pet ◽  
Tau Pet Imaging ◽  
Amyloid Pet Imaging

scholarly journals Associations of Fully Automated CSF and Novel Plasma Biomarkers With Alzheimer Disease Neuropathology at Autopsy

Neurology ◽  
2021 ◽  
pp. 10.1212/WNL.0000000000012513
Author(s):  
Michel J. Grothe ◽  
Alexis Moscoso ◽  
Nicholas J. Ashton ◽  
Thomas K. Karikari ◽  
Juan Lantero-Rodriguez ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Csf Biomarkers ◽  
Amyloid Pet ◽  
Braak Stage ◽  
Neuritic Plaques ◽  
Neurofilament Light ◽  
T Tau

Objective:To study cerebrospinal fluid (CSF) biomarkers of Alzheimer’s disease (AD) analyzed by fully automated Elecsys immunoassays in comparison to neuropathologic gold standards, and compare their accuracy to plasma phosphorylated tau (p-tau181) measured using a novel Simoa method.Methods:We studied ante-mortem Elecsys-derived CSF biomarkers in 45 individuals who underwent standardized post-mortem assessments of AD and non-AD neuropathologic changes at autopsy. In a subset of 26 participants, we also analysed ante-mortem levels of plasma p-tau181 and neurofilament light (NfL). Reference biomarker values were obtained from 146 amyloid-PET-negative healthy controls (HC).Results:All CSF biomarkers clearly distinguished pathology-confirmed AD dementia (N=27) from HC (AUCs=0.86-1.00). CSF total-tau (t-tau), p-tau181, and their ratios with Aβ1-42, also accurately distinguished pathology-confirmed AD from non-AD dementia (N=8; AUCs=0.94-0.97). In pathology-specific analyses, intermediate-to-high Thal amyloid phases were best detected by CSF Aβ1-42 (AUC[95% CI]=0.91[0.81-1]), while intermediate-to-high CERAD neuritic plaques and Braak tau stages were best detected by CSF p-tau181 (AUC=0.89[0.79-0.99] and 0.88[0.77-0.99], respectively). Optimal Elecsys biomarker cut-offs were derived at 1097/229/19 pg/ml for Aβ1-42, t-tau, and p-tau181. In the plasma subsample, both plasma p-tau181 (AUC=0.91[0.86-0.96]) and NfL (AUC=0.93[0.87-0.99]) accurately distinguished pathology-confirmed AD (N=14) from HC. However, only p-tau181 distinguished AD from non-AD dementia cases (N=4; AUC=0.96[0.88-1.00]), and showed a similar, though weaker, pathologic specificity for neuritic plaques (AUC=0.75[0.52-0.98]) and Braak stage (AUC=0.71[0.44-0.98]) as CSF p-tau181.Conclusions:Elecsys-derived CSF biomarkers detect AD neuropathologic changes with very high discriminative accuracy in-vivo. Preliminary findings support the use of plasma p-tau181 as an easily accessible and scalable biomarker of AD pathology.Classification of Evidence:This study provides Class II evidence that fully-automated CSF t-tau and p-tau181measurements discriminate between autopsy-confirmed Alzheimer's disease and other dementias.

Elevated Tau PET Signal Depends on Abnormal Amyloid Levels and Correlates with Cognitive Impairment in Elderly Persons without Dementia

2020 ◽  
Vol 78 (1) ◽  
pp. 395-404 ◽  
Author(s):  
Rui-Qi Zhang ◽  
Shi-Dong Chen ◽  
Xue-Ning Shen ◽  
Yu-Xiang Yang ◽  
Jia-Ying Lu ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Executive Function ◽  
Amyloid Β ◽  
Amyloid Pet ◽  
Elderly Persons ◽  
Cross Sectional ◽  
Memory Decline ◽  
Tau Pet

Background: The recent developed PET ligands for amyloid-β (Aβ) and tau allow these two neuropathological hallmarks of Alzheimer’s disease (AD) to be mapped and quantified in vivo and to be examined in relation to cognition. Objective: To assess the associations among Aβ, tau, and cognition in non-demented subjects. Methods: Three hundred eighty-nine elderly participants without dementia from the Alzheimer’s Disease Neuroimaging Initiative underwent tau and amyloid PET scans. Cross-sectional comparisons and longitudinal analyses were used to evaluate the relationship between Aβ and tau accumulation. The correlations between biomarkers of both pathologies and performance in memory and executive function were measured. Results: Increased amyloid-PET retention was associated with greater tau-PET retention in widespread cortices. We observed a significant tau increase in the temporal composite regions of interest over 24 months in Aβ+ but not Aβ– subjects. Finally, tau-PET retention but not amyloid-PET retention significantly explained the variance in memory and executive function. Higher level of tau was associated with greater longitudinal memory decline. Conclusion: These findings suggested PET-detectable Aβ plaque pathology may be a necessary antecedent for tau-PET signal elevation. Greater tau-PET retention may demonstrate poorer cognition and predict prospective memory decline in non-demented subjects.

scholarly journals White matter hyperintensities: relationship to amyloid and tau burden

Brain ◽  
2019 ◽  
Vol 142 (8) ◽  
pp. 2483-2491 ◽  
Author(s):  
Jonathan Graff-Radford ◽  
Eider M Arenaza-Urquijo ◽  
David S Knopman ◽  
Christopher G Schwarz ◽  
Robert D Brown ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
White Matter ◽  
White Matter Hyperintensities ◽  
Cerebral Microbleeds ◽  
Amyloid Angiopathy ◽  
Amyloid Pet ◽  
Gradient Recall Echo ◽  
Tau Pet ◽  
Topographic Pattern

Abstract Although white matter hyperintensities have traditionally been viewed as a marker of vascular disease, recent pathology studies have found an association between white matter hyperintensities and Alzheimer’s disease pathologies. The objectives of this study were to investigate the topographic patterns of white matter hyperintensities associated with Alzheimer’s disease biomarkers measured using PET. From the population-based Mayo Clinic Study of Aging, 434 participants without dementia (55% male) with FLAIR and gradient recall echo MRI, tau-PET (AV-1451) and amyloid-PET scans were identified. A subset had cerebral microbleeds detected on T2* gradient recall echo scans. White matter hyperintensities were semi-automatically segmented using FLAIR MRI in participant space and normalized to a custom template. We used statistical parametric mapping 12-based, voxel-wise, multiple-regression analyses to detect white matter hyperintense regions associated with Alzheimer’s biomarkers (global amyloid from amyloid-PET and meta-regions of interest tau uptake from tau-PET) after adjusting for age, sex and hypertension. For amyloid associations, we additionally adjusted for tau and vice versa. Topographic patterns of amyloid-associated white matter hyperintensities included periventricular white matter hyperintensities (frontal and parietal lobes). White matter hyperintense volumes in the detected topographic pattern correlated strongly with lobar cerebral microbleeds (P < 0.001, age and sex adjusted Cohen’s d = 0.703). In contrast, there were no white matter hyperintense regions significantly associated with increased tau burden using voxel-based analysis or region-specific analysis. Among non-demented elderly, amyloid load correlated with a topographic pattern of white matter hyperintensities. Further, the amyloid-associated, white matter hyperintense regions strongly correlated with lobar cerebral microbleeds suggesting that cerebral amyloid angiopathy contributes to the relationship between amyloid and white matter hyperintensities. The study did not support an association between increased tau burden and white matter hyperintense burden.

scholarly journals A blood-based diagnostic test incorporating plasma Aβ42/40 ratio, ApoE proteotype, and age accurately identifies brain amyloid status: findings from a multi cohort validity analysis

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Tim West ◽  
Kristopher M. Kirmess ◽  
Matthew R. Meyer ◽  
Mary S. Holubasch ◽  
Stephanie S. Knapik ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
High Resolution Mass Spectrometry ◽  
Clinical Performance ◽  
Characteristic Curve ◽  
Youden Index ◽  
Amyloid Pet ◽  
Drug Trials ◽  
Site Specific

Abstract Background The development of blood-based biomarker tests that are accurate and robust for Alzheimer’s disease (AD) pathology have the potential to aid clinical diagnosis and facilitate enrollment in AD drug trials. We developed a high-resolution mass spectrometry (MS)-based test that quantifies plasma Aβ42 and Aβ40 concentrations and identifies the ApoE proteotype. We evaluated robustness, clinical performance, and commercial viability of this MS biomarker assay for distinguishing brain amyloid status. Methods We used the novel MS assay to analyze 414 plasma samples that were collected, processed, and stored using site-specific protocols, from six independent US cohorts. We used receiver operating characteristic curve (ROC) analyses to assess assay performance and accuracy for predicting amyloid status (positive, negative, and standard uptake value ratio; SUVR). After plasma analysis, sites shared brain amyloid status, defined using diverse, site-specific methods and cutoff values; amyloid PET imaging using various tracers or CSF Aβ42/40 ratio. Results Plasma Aβ42/40 ratio was significantly (p < 0.001) lower in the amyloid positive vs. negative participants in each cohort. The area under the ROC curve (AUC-ROC) was 0.81 (95% CI = 0.77–0.85) and the percent agreement between plasma Aβ42/40 and amyloid positivity was 75% at the optimal (Youden index) cutoff value. The AUC-ROC (0.86; 95% CI = 0.82–0.90) and accuracy (81%) for the plasma Aβ42/40 ratio improved after controlling for cohort heterogeneity. The AUC-ROC (0.90; 95% CI = 0.87–0.93) and accuracy (86%) improved further when Aβ42/40, ApoE4 copy number and participant age were included in the model. Conclusions This mass spectrometry-based plasma biomarker test: has strong diagnostic performance; can accurately distinguish brain amyloid positive from amyloid negative individuals; may aid in the diagnostic evaluation process for Alzheimer’s disease; and may enhance the efficiency of enrolling participants into Alzheimer’s disease drug trials.

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