| 1. |
- Sexton, Claire E., et al.
(författare)
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Novel avenues of tau research
- 2024
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Ingår i: Alzheimer's and Dementia. - 1552-5260. ; 20:3, s. 2240-2261
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Forskningsöversikt (refereegranskat)abstract
- INTRODUCTION: The pace of innovation has accelerated in virtually every area of tau research in just the past few years. METHODS: In February 2022, leading international tau experts convened to share selected highlights of this work during Tau 2022, the second international tau conference co-organized and co-sponsored by the Alzheimer's Association, CurePSP, and the Rainwater Charitable Foundation. RESULTS: Representing academia, industry, and the philanthropic sector, presenters joined more than 1700 registered attendees from 59 countries, spanning six continents, to share recent advances and exciting new directions in tau research. DISCUSSION: The virtual meeting provided an opportunity to foster cross-sector collaboration and partnerships as well as a forum for updating colleagues on research-advancing tools and programs that are steadily moving the field forward.
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| 2. |
- Thijssen, Elisabeth H, et al.
(författare)
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Plasma phosphorylated tau 217 and phosphorylated tau 181 as biomarkers in Alzheimer's disease and frontotemporal lobar degeneration: a retrospective diagnostic performance study.
- 2021
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Ingår i: The Lancet. Neurology. - 1474-4465 .- 1474-4422. ; 20:9, s. 739-752
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Tidskriftsartikel (refereegranskat)abstract
- Plasma tau phosphorylated at threonine 217 (p-tau217) and plasma tau phosphorylated at threonine 181 (p-tau181) are associated with Alzheimer's disease tau pathology. We compared the diagnostic value of both biomarkers in cognitively unimpaired participants and patients with a clinical diagnosis of mild cognitive impairment, Alzheimer's disease syndromes, or frontotemporal lobar degeneration (FTLD) syndromes.In this retrospective multicohort diagnostic performance study, we analysed plasma samples, obtained from patients aged 18-99 years old who had been diagnosed with Alzheimer's disease syndromes (Alzheimer's disease dementia, logopenic variant primary progressive aphasia, or posterior cortical atrophy), FTLD syndromes (corticobasal syndrome, progressive supranuclear palsy, behavioural variant frontotemporal dementia, non-fluent variant primary progressive aphasia, or semantic variant primary progressive aphasia), or mild cognitive impairment; the participants were from the University of California San Francisco (UCSF) Memory and Aging Center, San Francisco, CA, USA, and the Advancing Research and Treatment for Frontotemporal Lobar Degeneration Consortium (ARTFL; 17 sites in the USA and two in Canada). Participants from both cohorts were carefully characterised, including assessments of CSF p-tau181, amyloid-PET or tau-PET (or both), and clinical and cognitive evaluations. Plasma p-tau181 and p-tau217 were measured using electrochemiluminescence-based assays, which differed only in the biotinylated antibody epitope specificity. Receiver operating characteristic analyses were used to determine diagnostic accuracy of both plasma markers using clinical diagnosis, neuropathological findings, and amyloid-PET and tau-PET measures as gold standards. Difference between two area under the curve (AUC) analyses were tested with the Delong test.Data were collected from 593 participants (443 from UCSF and 150 from ARTFL, mean age 64 years [SD 13], 294 [50%] women) between July 1 and Nov 30, 2020. Plasma p-tau217 and p-tau181 were correlated (r=0·90, p<0·0001). Both p-tau217 and p-tau181 concentrations were increased in people with Alzheimer's disease syndromes (n=75, mean age 65 years [SD 10]) relative to cognitively unimpaired controls (n=118, mean age 61 years [SD 18]; AUC=0·98 [95% CI 0·95-1·00] for p-tau217, AUC=0·97 [0·94-0·99] for p-tau181; pdiff=0·31) and in pathology-confirmed Alzheimer's disease (n=15, mean age 73 years [SD 12]) versus pathologically confirmed FTLD (n=68, mean age 67 years [SD 8]; AUC=0·96 [0·92-1·00] for p-tau217, AUC=0·91 [0·82-1·00] for p-tau181; pdiff=0·22). P-tau217 outperformed p-tau181 in differentiating patients with Alzheimer's disease syndromes (n=75) from those with FTLD syndromes (n=274, mean age 67 years [SD 9]; AUC=0·93 [0·91-0·96] for p-tau217, AUC=0·91 [0·88-0·94] for p-tau181; pdiff=0·01). P-tau217 was a stronger indicator of amyloid-PET positivity (n=146, AUC=0·91 [0·88-0·94]) than was p-tau181 (n=214, AUC=0·89 [0·86-0·93]; pdiff=0·049). Tau-PET binding in the temporal cortex was more strongly associated with p-tau217 than p-tau181 (r=0·80 vs r=0·72; pdiff<0·0001, n=230).Both p-tau217 and p-tau181 had excellent diagnostic performance for differentiating patients with Alzheimer's disease syndromes from other neurodegenerative disorders. There was some evidence in favour of p-tau217 compared with p-tau181 for differential diagnosis of Alzheimer's disease syndromes versus FTLD syndromes, as an indication of amyloid-PET-positivity, and for stronger correlations with tau-PET signal. Pending replication in independent, diverse, and older cohorts, plasma p-tau217 and p-tau181 could be useful screening tools to identify individuals with underlying amyloid and Alzheimer's disease tau pathology.US National Institutes of Health, State of California Department of Health Services, Rainwater Charitable Foundation, Michael J Fox foundation, Association for Frontotemporal Degeneration, Alzheimer's Association.
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| 3. |
- Cullen, Nicholas C., et al.
(författare)
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Plasma biomarkers of Alzheimer’s disease improve prediction of cognitive decline in cognitively unimpaired elderly populations
- 2021
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 12:1
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Tidskriftsartikel (refereegranskat)abstract
- Plasma biomarkers of amyloid, tau, and neurodegeneration (ATN) need to be characterized in cognitively unimpaired (CU) elderly individuals. We therefore tested if plasma measurements of amyloid-β (Aβ)42/40, phospho-tau217 (P-tau217), and neurofilament light (NfL) together predict clinical deterioration in 435 CU individuals followed for an average of 4.8 ± 1.7 years in the BioFINDER study. A combination of all three plasma biomarkers and basic demographics best predicted change in cognition (Pre-Alzheimer’s Clinical Composite; R2 = 0.14, 95% CI [0.12–0.17]; P < 0.0001) and subsequent AD dementia (AUC = 0.82, 95% CI [0.77–0.91], P < 0.0001). In a simulated clinical trial, a screening algorithm combining all three plasma biomarkers would reduce the required sample size by 70% (95% CI [54–81]; P < 0.001) with cognition as trial endpoint, and by 63% (95% CI [53–70], P < 0.001) with subsequent AD dementia as trial endpoint. Plasma ATN biomarkers show usefulness in cognitively unimpaired populations and could make large clinical trials more feasible and cost-effective.
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| 4. |
- Mattsson-Carlgren, Niklas, et al.
(författare)
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Longitudinal plasma p-tau217 is increased in early stages of Alzheimer's disease
- 2020
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 143:11, s. 3234-3241
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Tidskriftsartikel (refereegranskat)abstract
- Plasma levels of tau phosphorylated at threonine-217 (p-tau217) is a candidate tool to monitor Alzheimer's disease. We studied 150 cognitively unimpaired participants and 100 patients with mild cognitive impairment in the Swedish BioFINDER study. P-tau217 was measured repeatedly for up to 6 years (median three samples per person, median time from first to last sample, 4.3 years). Preclinical (amyloid-β-positive cognitively unimpaired, n = 62) and prodromal (amyloid-β-positive mild cognitive impairment, n = 49) Alzheimer's disease had accelerated p-tau217 compared to amyloid-β-negative cognitively unimpaired (β = 0.56, P < 0.001, using linear mixed effects models) and amyloid-β-negative mild cognitive impairment patients (β = 0.67, P < 0.001), respectively. Mild cognitive impairment patients who later converted to Alzheimer's disease dementia (n = 40) had accelerated p-tau217 compared to other mild cognitive impairment patients (β = 0.79, P < 0.001). P-tau217 did not change in amyloid-β-negative participants, or in patients with mild cognitive impairment who did not convert to Alzheimer's disease dementia. For 80% power, 109 participants per arm were required to observe a slope reduction in amyloid-β-positive cognitively unimpaired (71 participants per arm in amyloid-β-positive mild cognitive impairment). Longitudinal increases in p-tau217 correlated with longitudinal worsening of cognition and brain atrophy. In summary, plasma p-tau217 increases during early Alzheimer's disease and can be used to monitor disease progression.
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| 5. |
- Aguillon, David, et al.
(författare)
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Plasma p-tau217 predicts in vivo brain pathology and cognition in autosomal dominant Alzheimer's disease
- 2023
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:6, s. 2585-2594
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Plasma-measured tau phosphorylated at threonine 217 (p-tau217) is a potential non-invasive biomarker of Alzheimer's disease (AD). We investigated whether plasma p-tau217 predicts subsequent cognition and positron emission tomography (PET) markers of pathology in autosomal dominant AD. Methods: We analyzed baseline levels of plasma p-tau217 and its associations with amyloid PET, tau PET, and word list delayed recall measured 7.61 years later in non-demented age- and education-matched presenilin-1 E280A carriers (n = 24) and non-carrier (n = 20) family members. Results: Carriers had higher plasma p-tau217 levels than non-carriers. Baseline plasma p-tau217 was associated with subsequent amyloid and tau PET pathology levels and cognitive function. Discussion: Our findings suggest that plasma p-tau217 predicts subsequent brain pathological burden and memory performance in presenilin-1 E280A carriers. These results provide support for plasma p-tau217 as a minimally invasive diagnostic and prognostic biomarker for AD, with potential utility in clinical practice and trials. Highlights: Non-demented presenilin-1 E280A carriers have higher plasma tau phosphorylated at threonine 217 (p-tau217) than do age-matched non-carriers. Higher baseline p-tau217 is associated with greater future amyloid positron emission tomography (PET) pathology burden. Higher baseline p-tau217 is associated with greater future tau PET pathology burden. Higher baseline p-tau217 is associated with worse future memory performance.
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| 6. |
- Bayoumy, Sherif, et al.
(författare)
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Clinical and analytical comparison of six Simoa assays for plasma P-tau isoforms P-tau181, P-tau217, and P-tau231.
- 2021
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Ingår i: Alzheimer's research & therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Studies using different assays and technologies showed highly promising diagnostic value of plasma phosphorylated (P-)tau levels for Alzheimer's disease (AD). We aimed to compare six P-tau Simoa assays, including three P-tau181 (Eli Lilly, ADx, Quanterix), one P-tau217 (Eli Lilly), and two P-tau231 (ADx, Gothenburg).We studied the analytical (sensitivity, precision, parallelism, dilution linearity, and recovery) and clinical (40 AD dementia patients, age 66±8years, 50%F; 40 age- and sex-matched controls) performance of the assays.All assays showed robust analytical performance, and particularly P-tau217 Eli Lilly; P-tau231 Gothenburg and all P-tau181 assays showed robust clinical performance to differentiate AD from controls, with AUCs 0.936-0.995 (P-tau231 ADx: AUC=0.719). Results obtained with all P-tau181 assays, P-tau217 Eli Lilly assay, and P-tau231 Gothenburg assay strongly correlated (Spearman's rho>0.86), while correlations with P-tau231 ADx results were moderate (rho<0.65).P-tau isoforms can be measured robustly by several novel high-sensitive Simoa assays.
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| 7. |
- Cullen, Nicholas C., et al.
(författare)
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Individualized prognosis of cognitive decline and dementia in mild cognitive impairment based on plasma biomarker combinations
- 2021
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Ingår i: Nature Aging. - : Springer Science and Business Media LLC. - 2662-8465. ; 1, s. 114-123
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Tidskriftsartikel (refereegranskat)abstract
- We developed models for individualized risk prediction of cognitive decline in mild cognitive impairment (MCI) using plasma biomarkers of β-amyloid (Aβ), tau and neurodegeneration. A total of 573 patients with MCI from the Swedish BioFINDER study and the Alzheimer’s Disease Neuroimaging Initiative (ADNI) were included in the study. The primary outcomes were longitudinal cognition and conversion to Alzheimer’s disease (AD) dementia. A model combining tau phosphorylated at threonine 181 (P-tau181) and neurofilament light (NfL), but not Aβ42/Aβ40, had the best prognosis performance of all models (area under the curve = 0.88 for 4-year conversion to AD in BioFINDER, validated in ADNI), was stronger than a basic model of age, sex, education and baseline cognition, and performed similarly to cerebrospinal fluid biomarkers. A publicly available online tool for individualized prognosis in MCI based on our combined plasma biomarker models is introduced. Combination of plasma biomarkers may be of high value to identify individuals with MCI who will progress to AD dementia in clinical trials and in clinical practice.
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| 8. |
- Groot, Colin, et al.
(författare)
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Diagnostic and prognostic performance to detect Alzheimer's disease and clinical progression of a novel assay for plasma p-tau217
- 2022
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Ingår i: Alzheimer's Research & Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 14:1, s. 1-12
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Recent advances in disease-modifying treatments highlight the need for accurately identifying individuals in early Alzheimer's disease (AD) stages and for monitoring of treatment effects. Plasma measurements of phosphorylated tau (p-tau) are a promising biomarker for AD, but different assays show varying diagnostic and prognostic accuracies. The objective of this study was to determine the clinical performance of a novel plasma p-tau217 (p-tau217) assay, p-tau217+ Janssen, and perform a head-to-head comparison to an established assay, plasma p-tau217 Lilly, within two independent cohorts . METHODS: The study consisted of two cohorts, cohort 1 (27 controls and 25 individuals with mild-cognitive impairment [MCI]) and cohort 2 including 147 individuals with MCI at baseline who were followed for an average of 4.92 (SD 2.09) years. Receiver operating characteristic analyses were used to assess the performance of both assays to detect amyloid-β status (+/-) in CSF, distinguish MCI from controls, and identify subjects who will convert from MCI to AD dementia. General linear and linear mixed-effects analyses were used to assess the associations between p-tau and baseline, and annual change in Mini-Mental State Examination (MMSE) scores. Spearman correlations were used to assess the associations between the two plasma measures, and Bland-Altmann plots were examined to assess the agreement between the assays. RESULTS: Both assays showed similar performance in detecting amyloid-β status in CSF (plasma p-tau217+ Janssen AUC = 0.91 vs plasma p-tau217 Lilly AUC = 0.89), distinguishing MCI from controls (plasma p-tau217+ Janssen AUC = 0.91 vs plasma p-tau217 Lilly AUC = 0.91), and predicting future conversion from MCI to AD dementia (plasma p-tau217+ Janssen AUC = 0.88 vs p-tau217 Lilly AUC = 0.89). Both assays were similarly related to baseline (plasma p-tau217+ Janssen rho = -0.39 vs p-tau217 Lilly rho = -0.35), and annual change in MMSE scores (plasma p-tau217+ Janssenr = -0.45 vs p-tau217 Lillyr = -0.41). Correlations between the two plasma measures were rho = 0.69, p < 0.001 in cohort 1 and rho = 0.70, p < 0.001 in cohort 2. Bland-Altmann plots revealed good agreement between plasma p-tau217+ Janssen and plasma p-tau217 Lilly in both cohorts (cohort 1, 51/52 [98%] within 95%CI; cohort 2, 139/147 [95%] within 95%CI). CONCLUSIONS: Taken together, our results indicate good diagnostic and prognostic performance of the plasma p-tau217+ Janssen assay, similar to the p-tau217 Lilly assay.
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| 9. |
- Hall, Sara, et al.
(författare)
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Plasma Phospho-Tau Identifies Alzheimer's Co-Pathology in Patients with Lewy Body Disease
- 2021
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Ingår i: Movement Disorders. - : Wiley. - 0885-3185 .- 1531-8257. ; 36:3, s. 767-771
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Tidskriftsartikel (refereegranskat)abstract
- Background: Alzheimer's disease co-pathology is common in dementia with Lewy bodies and Parkinson's disease with dementia (Lewy body disease) and can reliably be detected with positron emission tomography (PET) or cerebrospinal fluid (CSF) biomarkers. Recently developed blood biomarkers are more accessible and less expensive alternatives. Objective: To investigate if plasma phospho-tau217 and phospho-tau181 can detect Alzheimer's pathology in Lewy body disease with dementia. Methods: In this cross-sectional study we investigated plasma phospho-tau217 and phospho-tau181 in 35 patients with Lewy body disease with dementia. Patients underwent tau-PET imaging (18F-RO948). Results: Plasma phospho-tau217 correlated with plasma phospho-tau181, CSF phospho-tau217 (rs = 0.68, P < 0.001), and negatively with CSF β-amyloid42/40 (rs = −0.52, P = 0.001). Plasma phospho-tau217 and phospho-tau181 correlated with tau-PET signal in the temporal cortex (rs > 0.56, P < 0.001) and predicted abnormal tau-PET status and β-amyloid status (area under the curve > 0.78 and > 0.81, respectively). Conclusion: Plasma phospho-tau might be a useful marker for Alzheimer's co-pathology in Lewy body disease with dementia.
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| 10. |
- Janelidze, Shorena, et al.
(författare)
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Associations of Plasma Phospho-Tau217 Levels with Tau Positron Emission Tomography in Early Alzheimer Disease
- 2021
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149. ; 78:2, s. 149-149
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Tidskriftsartikel (refereegranskat)abstract
- Importance: There is an urgent need for inexpensive and minimally invasive blood biomarkers for Alzheimer disease (AD) that could be used to detect early disease changes. Objective: To assess how early in the course of AD plasma levels of tau phosphorylated at threonine 217 (P-tau217) start to change compared with levels of established cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers of AD pathology. Design, Setting, and Participants: This cohort study included cognitively healthy control individuals (n = 225) and participants with subjective cognitive decline (n = 89) or mild cognitive impairment (n = 176) from the BioFINDER-2 study. Participants were enrolled at 2 different hospitals in Sweden from January 2017 to October 2019. All study participants underwent plasma P-tau217 assessments and tau- and amyloid-β (Aβ)-PET imaging. A subcohort of 111 participants had 2 or 3 tau-PET scans. Main Outcomes and Measures: Changes in plasma P-tau217 levels in preclinical and prodromal AD compared with changes in CSF P-tau217 and PET measures. Results: Of 490 participants, 251 were women (51.2%) and the mean (SD) age was 65.9 (13.1) years. Plasma P-tau217 levels were increased in cognitively unimpaired participants with abnormal Aβ-PET but normal tau-PET in the entorhinal cortex (Aβ-PET+/ tau-PET- group vs Aβ-PET-/ tau-PET- group: median, 2.2 pg/mL [interquartile range (IQR), 1.5-2.9 pg/mL] vs 0.7 pg/mL [IQR, 0.3-1.4 pg/mL]). Most cognitively unimpaired participants who were discordant for plasma P-tau217 and tau-PET were positive for plasma P-tau217 and negative for tau-PET (P-tau217+/tau-PET-: 36 [94.7%]; P-tau217-/tau-PET+: 2 [5.3%]). Event-based modeling of cross-sectional data predicted that in cognitively unimpaired participants and in those with mild cognitive impairment, both plasma and CSF P-tau217 would change before the tau-PET signal in the entorhinal cortex, followed by more widespread cortical tau-PET changes. When testing the association with global Aβ load in nonlinear spline models, both plasma and CSF P-tau217 were increased at lower Aβ-PET values compared with tau-PET measures. Among participants with normal baseline tau-PET, the rates of longitudinal increase in tau-PET in the entorhinal cortex were higher in those with abnormal plasma P-tau217 at baseline (median standardized uptake value ratio, 0.029 [IQR, -0.006 to 0.041] vs -0.001 [IQR, -0.021 to 0.020]; Mann-Whitney U, P =.02). Conclusions and Relevance: In this cohort study, plasma P-tau217 levels were increased during the early preclinical stages of AD when insoluble tau aggregates were not yet detectable by tau-PET. Plasma P-tau217 may hold promise as a biomarker for early AD brain pathology.
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| 11. |
- Janelidze, Shorena, et al.
(författare)
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Cerebrospinal fluid p-tau217 performs better than p-tau181 as a biomarker of Alzheimer’s disease
- 2020
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Cerebrospinal fluid (CSF) p-tau181 (tau phosphorylated at threonine 181) is an established biomarker of Alzheimer’s disease (AD), reflecting abnormal tau metabolism in the brain. Here we investigate the performance of CSF p-tau217 as a biomarker of AD in comparison to p-tau181. In the Swedish BioFINDER cohort (n = 194), p-tau217 shows stronger correlations with the tau positron emission tomography (PET) tracer [18F]flortaucipir, and more accurately identifies individuals with abnormally increased [18F]flortaucipir retention. Furthermore, longitudinal increases in p-tau217 are higher compared to p-tau181 and better correlate with [18F]flortaucipir uptake. P-tau217 correlates better than p-tau181 with CSF and PET measures of neocortical amyloid-β burden and more accurately distinguishes AD dementia from non-AD neurodegenerative disorders. Higher correlations between p-tau217 and [18F]flortaucipir are corroborated in an independent EXPEDITION3 trial cohort (n = 32). The main results are validated using a different p-tau217 immunoassay. These findings suggest that p-tau217 might be more useful than p-tau181 in the diagnostic work up of AD.
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| 12. |
- Leuzy, Antoine, et al.
(författare)
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Blood-based biomarkers for Alzheimer's disease
- 2022
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4676 .- 1757-4684. ; 14:1
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Forskningsöversikt (refereegranskat)abstract
- Neurodegenerative disorders such as Alzheimer's disease (AD) represent a mounting public health challenge. As these diseases are difficult to diagnose clinically, biomarkers of underlying pathophysiology are playing an ever-increasing role in research, clinical trials, and in the clinical work-up of patients. Though cerebrospinal fluid (CSF) and positron emission tomography (PET)-based measures are available, their use is not widespread due to limitations, including high costs and perceived invasiveness. As a result of rapid advances in the development of ultra-sensitive assays, the levels of pathological brain- and AD-related proteins can now be measured in blood, with recent work showing promising results. Plasma P-tau appears to be the best candidate marker during symptomatic AD (i.e., prodromal AD and AD dementia) and preclinical AD when combined with Aβ42/Aβ40. Though not AD-specific, blood NfL appears promising for the detection of neurodegeneration and could potentially be used to detect the effects of disease-modifying therapies. This review provides an overview of the progress achieved thus far using AD blood-based biomarkers, highlighting key areas of application and unmet challenges.
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| 13. |
- Leuzy, Antoine, et al.
(författare)
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Comparing the Clinical Utility and Diagnostic Performance of Cerebrospinal Fluid P-Tau181, P-Tau217 and P-Tau231 Assays
- 2021
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Ingår i: Neurology. - 1526-632X. ; 97:17, s. 1681-1694
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND OBJECTIVES: Phosphorylated tau (P-tau) in cerebrospinal fluid (CSF) is considered an important biomarker in Alzheimer's disease (AD) and has been incorporated in recent diagnostic criteria. Several variants exist, including P-tau at threonines 181 (P-tau181), 217 (P-tau217) and 231 (P-tau231). However, no studies have compared their diagnostic performance or association to amyloid-β (Aβ) and Tau positron emission tomography (PET). Understanding which P-tau variant to use remains an important yet answered question. We aimed to compare the diagnostic accuracy of P-tau181, P-tau217 and P-tau231 in CSF for AD and their association with Aβ and Tau-PET.METHODS: 629 subjects from the Swedish BioFINDER-2 study were included (cognitively unimpaired, n=334; Aβ-positive mild cognitive impairment, n=84; AD dementia, n=119; and non-AD disorders, n=92). In addition to P-tau181 and P-tau217 measured using assays with the same detector antibodies from Eli Lilly (P-tau181Lilly, P-tau217Lilly) and P-tau231, we also included P-tau181 measurements from two commonly used assays (Innotest and Elecsys).RESULTS: Though all P-tau variants increased across the AD continuum, P-tau217Lilly showed the greatest dynamic range (13-fold-increase vs 1.9-5.4-fold-increase for other P-tau variants for AD dementia vs non-AD). P-tau217Lilly showed stronger correlations with Aβ- and Tau-PET (P<0.0001). P-tau217Lilly exhibited higher accuracy than other P-tau variants for separating AD dementia from non-AD (AUC, 0.991vs 0.906-0.982, P<0.0001) and for identifying Aβ- (AUC, 0.951 vs 0.816-0.924, P<0.0001) and Tau-PET positivity (AUC, 0.957 vs 0.836-0.938, P<0.0001). Finally, P-tau181Lilly generally performed better than the other P-tau181 assays, (e.g., AD dementia vs non-AD, AUC, 0.976 vs 0.923, P<0.0001).DISCUSSION: CSF P-tau217Lilly seem to be more useful than other included P-tau assays in the work-up of AD. Varied results across P-tau181 assays also highlights the importance of anti-tau antibodies for biomarker performance.CLASSIFICATION OF EVIDENCE: This study provides class II evidence that phosphorylated tau at threonine 217 provides higher diagnostic accuracy for diagnosis of AD dementia than P-tau at threonine 181 or 231.
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| 14. |
- Mattsson-Carlgren, Niklas, et al.
(författare)
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Soluble P-tau217 reflects amyloid and tau pathology and mediates the association of amyloid with tau
- 2021
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4676 .- 1757-4684. ; 13:6
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Tidskriftsartikel (refereegranskat)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, but P-tau217 was not elevated in patients with non-Alzheimer’s disease tauopathies (N = 9). Several findings were replicated in a cohort with PET imaging (“BioFINDER-2”, N = 426), where β-amyloid and tau PET were independently associated with P-tau217. P-tau217 concentrations 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 concentration 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.
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| 15. |
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| 16. |
- Ossenkoppele, Rik, et al.
(författare)
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Tau PET correlates with different Alzheimer’s disease-related features compared to CSF and plasma p-tau biomarkers
- 2021
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Ingår i: EMBO Molecular Medicine. - : EMBO. - 1757-4676 .- 1757-4684. ; 13:8
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Tidskriftsartikel (refereegranskat)abstract
- PET, CSF and plasma biomarkers of tau pathology may be differentially associated with Alzheimer's disease (AD)-related demographic, cognitive, genetic and neuroimaging markers. We examined 771 participants with normal cognition, mild cognitive impairment or dementia from BioFINDER-2 (n=400) and ADNI (n=371). All had tau-PET ([18F]RO948 in BioFINDER-2, [18F]flortaucipir in ADNI) and CSF p-tau181 biomarkers available. Plasma p-tau181 and plasma/CSF p-tau217 were available in BioFINDER-2 only. Concordance between PET, CSF and plasma tau biomarkers ranged between 66 and 95%. Across the whole group, ridge regression models showed that increased CSF and plasma p-tau181 and p-tau217 levels were independently of tau PET associated with higher age, and APOEɛ4-carriership and Aβ-positivity, while increased tau-PET signal in the temporal cortex was associated withworse cognitive performance and reduced cortical thickness. We conclude that biofluid and neuroimaging markers of tau pathology convey partly independent information, with CSF and plasma p-tau181 and p-tau217 levels being more tightly linked with early markers of AD (especially Aβ-pathology), while tau-PET shows the strongest associations with cognitive and neurodegenerative markers of disease progression.
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| 17. |
- Pereira, Joana B., et al.
(författare)
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Plasma markers predict changes in amyloid, tau, atrophy and cognition in non-demented subjects
- 2021
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Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 144:9, s. 2826-2836
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Tidskriftsartikel (refereegranskat)abstract
- It is currently unclear whether plasma biomarkers can be used as independent prognostic tools to predict changes associated with early Alzheimer's disease. In this study, we sought to address this question by assessing whether plasma biomarkers can predict changes in amyloid load, tau accumulation, brain atrophy and cognition in non-demented individuals. To achieve this, plasma amyloid-β 42/40 (Aβ42/40), phosphorylated-tau181, phosphorylated-tau217 and neurofilament light were determined in 159 non-demented individuals, 123 patients with Alzheimer's disease dementia and 35 patients with a non-Alzheimer's dementia from the Swedish BioFINDER-2 study, who underwent longitudinal amyloid (18F-flutemetamol) and tau (18F-RO948) PET, structural MRI (T1-weighted) and cognitive testing. Our univariate linear mixed effect models showed there were several significant associations between the plasma biomarkers with imaging and cognitive measures. However, when all biomarkers were included in the same multivariate linear mixed effect models, we found that increased longitudinal amyloid-PET signals were independently predicted by low baseline plasma Aβ42/40 (P = 0.012), whereas increased tau-PET signals, brain atrophy and worse cognition were independently predicted by high plasma phosphorylated-tau217 (P < 0.004). These biomarkers performed equally well or better than the corresponding biomarkers measured in the CSF. In addition, they showed a similar performance to binary plasma biomarker values defined using the Youden index, which can be more easily implemented in the clinic. In addition, plasma Aβ42/40 and phosphorylated-tau217 did not predict longitudinal changes in patients with a non-Alzheimer's neurodegenerative disorder. In conclusion, our findings indicate that plasma Aβ42/40 and phosphorylated-tau217 could be useful in clinical practice, research and drug development as prognostic markers of future Alzheimer's disease pathology.
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| 18. |
- Verberk, Inge M.W., et al.
(författare)
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Characterization of pre-analytical sample handling effects on a panel of Alzheimer's disease–related blood-based biomarkers : Results from the Standardization of Alzheimer's Blood Biomarkers (SABB) working group
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:8, s. 1484-1497
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Pre-analytical sample handling might affect the results of Alzheimer's disease blood-based biomarkers. We empirically tested variations of common blood collection and handling procedures. Methods: We created sample sets that address the effect of blood collection tube type, and of ethylene diamine tetraacetic acid plasma delayed centrifugation, centrifugation temperature, aliquot volume, delayed storage, and freeze–thawing. We measured amyloid beta (Aβ)42 and 40 peptides with six assays, and Aβ oligomerization-tendency (OAβ), amyloid precursor protein (APP)699-711, glial fibrillary acidic protein (GFAP), neurofilament light (NfL), total tau (t-tau), and phosphorylated tau181. Results: Collection tube type resulted in different values of all assessed markers. Delayed plasma centrifugation and storage affected Aβ and t-tau; t-tau was additionally affected by centrifugation temperature. The other markers were resistant to handling variations. Discussion: We constructed a standardized operating procedure for plasma handling, to facilitate introduction of blood-based biomarkers into the research and clinical settings.
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| 19. |
- Wennström, Malin, et al.
(författare)
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Cellular localization of p-tau217 in brain and its association with p-tau217 plasma levels
- 2022
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Ingår i: Acta Neuropathologica Communications. - : Springer Science and Business Media LLC. - 2051-5960. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies highlight phosphorylated tau (p-tau) at threonine tau 217 (p-tau217) as a new promising plasma biomarker for pathological changes implicated in Alzheimer’s disease (AD), but the specific brain pathological events related to the alteration in p-tau217 plasma levels are still largely unknown. Using immunostaining techniques of postmortem AD brain tissue, we show that p-tau217 is found in neurofibrillary tangles (NFTs) and neuropil threads that are also positive for p-tau181, 202, 202/205, 231, and 369/404. The p-tau217, but not the other five p-tau variants, was also prominently seen in vesicles structure positive for markers of granulovacuolar degeneration bodies and multi-vesicular bodies. Further, individuals with a high likelihood of AD showed significantly higher p-tau217 area fraction in 4 different brain areas (entorhinal cortex, inferior temporal gyrus, and superior frontal gyrus) compared to those with Primary age related tauopathy or other non-AD tauopathies. The p-tau217 area fraction correlated strongly with total amyloid-beta (Aβ) and NFT brain load when the whole group was analyzed. Finally, the mean p-tau217 area fraction correlated significantly with p-tau217 concentrations in antemortem collected plasma specifically in individuals with amyloid plaques and not in those without amyloid plaques. These studies highlight differences in cellular localization of different p-tau variants and suggest that plasma levels of p-tau217 reflect an accumulation of p-tau217 in presence of Aβ plaque load.
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