| 21. |
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| 22. |
- Engelborghs, Sebastiaan, et al.
(författare)
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Consensus guidelines for lumbar puncture in patients with neurological diseases
- 2017
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Ingår i: Alzheimer's and Dementia: Diagnosis, Assessment and Disease Monitoring. - : Wiley. - 2352-8729. ; 8, s. 111-126
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Cerebrospinal fluid collection by lumbar puncture (LP) is performed in the diagnostic workup of several neurological brain diseases. Reluctance to perform the procedure is among others due to a lack of standards and guidelines to minimize the risk of complications, such as post-LP headache or back pain. Methods We provide consensus guidelines for the LP procedure to minimize the risk of complications. The recommendations are based on (1) data from a large multicenter LP feasibility study (evidence level II-2), (2) systematic literature review on LP needle characteristics and post-LP complications (evidence level II-2), (3) discussion of best practice within the Joint Programme Neurodegenerative Disease Research Biomarkers for Alzheimer's disease and Parkinson's Disease and Biomarkers for Multiple Sclerosis consortia (evidence level III). Results Our consensus guidelines address contraindications, as well as patient-related and procedure-related risk factors that can influence the development of post-LP complications. Discussion When an LP is performed correctly, the procedure is well tolerated and accepted with a low complication rate.
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| 23. |
- Groot, Colin, et al.
(författare)
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A biomarker profile of elevated CSF p-tau with normal tau PET is associated with increased tau accumulation rates on PET in early Alzheimer’s disease
- 2022
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Ingår i: Alzheimer's and Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:S1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Different tau biomarkers become abnormal at different stages of Alzheimer’s disease (AD), with CSF p-tau typically being elevated at subthreshold levels of tau-PET binding. To capitalize on the temporal order of tau biomarker-abnormality and capture the earliest changes of tau accumulation, we selected a group of amyloid-β-positive (A+) individuals with elevated CSF p-tau levels but negative tau-PET scans and assessed longitudinal changes in tau-PET, cortical thickness and cognitive decline. Method: Individuals without dementia (i.e., cognitively unimpaired (CU) or mild cognitive impairment, n=231) were selected from the BioFINDER-2 study. These subjects were categorized into biomarker groups based on Gaussian mixture modelling to determine cut-offs for abnormal CSF Aβ42/40 (A; <0.078), CSF p-tau217 (P; >110 pg/ml) and [18F]RO948 tau-PET SUVR within a temporal meta-ROI (T; SUVR >1.40). Resulting groups were: A+P-T- (concordant, n=30), A+P+T- (discordant, n=48) and A+P+T+ (concordant, n=18). We additionally used 135 A- CU individuals (A- CU) as a reference group (Tables 1 and 2). Differences in annual change in regional tau-PET SUVR, cortical thickness and cognition between the A+P+T- group and the other groups were assessed using general linear models, adjusted for age, sex, clinical diagnosis and (for cognitive measures) education. Result: Longitudinal change in tau-PET was faster in the A+P+T- group than in the A- CU and A+P-T- groups across medial temporal and neocortical regions, with the medial temporal increases being more pronounced. The A+P+T- group showed slower rate of increases in tau-PET compared to the A+P+T+ group, primarily in neocortical regions (Figures 1 and 2). We did not detect differences in yearly change in cortical thickness (Figure 3) or in cognitive decline (Figure 3) between the A+P+T- and A+P-T- groups. The A+P+T+ group, however, showed faster cognitive decline compared to all other groups. Conclusion: These findings suggest that the A+P+T- biomarker profile is associated with early tau accumulation, and with relative sparing of cortical thinning and cognitive decline compared to A+P+T+ individuals. Therefore, the A+P+T- group represents an interesting target-group for early anti-tau interventions and for examining the emergence of tau aggregates in early AD.
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| 24. |
- Groot, Colin, et al.
(författare)
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Phospho-tau with subthreshold tau-PET predicts increased tau accumulation rates in amyloid-positive individuals
- 2023
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Ingår i: Brain : a journal of neurology. - : Oxford University Press (OUP). - 1460-2156. ; 146:4, s. 1580-1591
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Tidskriftsartikel (refereegranskat)abstract
- Different tau biomarkers become abnormal at different stages of Alzheimer's disease, with CSF phospho-tau typically becoming elevated at subthreshold levels of tau-PET binding. To capitalize on the temporal order of tau biomarker-abnormality and capture the earliest changes of tau accumulation, we implemented an observational study design to examine longitudinal changes in Tau-PET, cortical thickness and cognitive decline in amyloid-β-positive (A+) individuals with elevated CSF P-tau levels (P+) but subthreshold Tau-PET retention (T-). To this end, individuals without dementia (i.e., cognitively unimpaired or mild cognitive impairment, N = 231) were selected from the BioFINDER-2 study. Amyloid-β-positive (A+) individuals were categorized into biomarker groups based on cut-offs for abnormal CSF P-tau217 and [18F]RO948 (Tau) PET, yielding groups of tau-concordant-negative (A + P-T-; n = 30), tau-discordant (i.e., A + P+T-; n = 48) and tau-concordant-positive (A + P+T+; n = 18) individuals. In addition, 135 amyloid-β-negative, tau-negative, cognitively unimpaired individuals served as controls. Differences in annual change in regional Tau-PET, cortical thickness and cognition between the groups were assessed using general linear models, adjusted for age, sex, clinical diagnosis and (for cognitive measures only) education. Mean follow-up time was ∼2 years. Longitudinal increase in Tau-PET was faster in the A + P+T- group than in the control and A + P-T- groups across medial temporal and neocortical regions, with the highest accumulation rates in the medial temporal lobe. The A + P+T- group showed a slower rate of increases in tau-PET compared to the A + P+T+ group, primarily in neocortical regions. We did not detect differences in yearly change in cortical thickness or in cognitive decline between the A + P+T- and A + P-T- groups. The A + P+T+ group, however, showed faster cognitive decline compared to all other groups. Altogether, these findings suggest that the A + P+T- biomarker profile in persons without dementia is associated with an isolated effect on increased Tau-PET accumulation rates but not on cortical thinning and cognitive decline. While this suggests that the tau-discordant biomarker profile is not strongly associated with short-term clinical decline, this group does represent an interesting population for monitoring effects of interventions with disease modifying agents on tau accumulation in early Alzheimer's disease, and for examining the emergence of tau aggregates in Alzheimer's disease. Further, we suggest to update the AT(N) criteria for Alzheimer's disease biomarker classification to APT(N).
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| 25. |
- Horie, Kanta, et al.
(författare)
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CSF MTBR-tau243 is a specific biomarker of tau tangle pathology in Alzheimer’s disease
- 2023
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Ingår i: Nature Medicine. - 1078-8956. ; 29:8, s. 1954-1963
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Tidskriftsartikel (refereegranskat)abstract
- Aggregated insoluble tau is one of two defining features of Alzheimer’s disease. Because clinical symptoms are strongly correlated with tau aggregates, drug development and clinical diagnosis need cost-effective and accessible specific fluid biomarkers of tau aggregates; however, recent studies suggest that the fluid biomarkers currently available cannot specifically track tau aggregates. We show that the microtubule-binding region (MTBR) of tau containing the residue 243 (MTBR-tau243) is a new cerebrospinal fluid (CSF) biomarker specific for insoluble tau aggregates and compared it to multiple other phosphorylated tau measures (p-tau181, p-tau205, p-tau217 and p-tau231) in two independent cohorts (BioFINDER-2, n = 448; and Knight Alzheimer Disease Research Center, n = 219). MTBR-tau243 was most strongly associated with tau-positron emission tomography (PET) and cognition, whereas showing the lowest association with amyloid-PET. In combination with p-tau205, MTBR-tau243 explained most of the total variance in tau-PET burden (0.58 ≤ R 2 ≤ 0.75) and the performance in predicting cognitive measures (0.34 ≤ R 2 ≤ 0.48) approached that of tau-PET (0.44 ≤ R 2 ≤ 0.52). MTBR-tau243 levels longitudinally increased with insoluble tau aggregates, unlike CSF p-tau species. CSF MTBR-tau243 is a specific biomarker of tau aggregate pathology, which may be utilized in interventional trials and in the diagnosis of patients. Based on these findings, we propose to revise the A/T/(N) criteria to include MTBR-tau243 as representing insoluble tau aggregates (‘T’).
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| 26. |
- Janelidze, Shorena, et al.
(författare)
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Detecting amyloid positivity in early Alzheimer's disease using combinations of plasma A beta 42/A beta 40 and p-tau
- 2022
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 18:2, s. 283-293
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: We studied usefulness of combining blood amyloid beta A(beta)42/A beta 40, phosphorylated tau (p-tau)217, and neurofilament light (NfL) to detect abnormal brain A beta deposition in different stages of early Alzheimer's disease (AD). Methods: Plasma biomarkers were measured using mass spectrometry (A beta 42/A beta 40) and immunoassays (p-tau217 and NfL) in cognitively unimpaired individuals (CU, N = 591) and patients with mild cognitive impairment (MCI, N = 304) from two independent cohorts (BioFINDER-1, BioFINDER-2). Results: In CU, a combination of plasma A beta 42/A beta 40 and p-tau217 detected abnormal brain A beta status with area under the curve (AUC) of 0.83 to 0.86. In MCI, the models including p-tau217 alone or A beta 42/A beta 40 and p-tau217 had similar AUCs (0.86-0.88); however, the latter showed improved model fit. The models were implemented in an online application providing individualized risk assessments (https://brainapps.shinyappas.io/PredictAAbplasma/). Discussion:A combination of plasma A beta 42/A beta 40 and p-tau217 discriminated A beta status with relatively high accuracy, whereas p-tau217 showed strongest associations with A beta pathology in MCI but not in CU.
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| 27. |
- Janelidze, Shorena, et al.
(författare)
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Plasma Phosphorylated Tau 217 and Aβ42/40 to Predict Early Brain Aβ Accumulation in People Without Cognitive Impairment
- 2024
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Ingår i: JAMA NEUROLOGY. - 2168-6149 .- 2168-6157.
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE Phase 3 trials of successful antiamyloid therapies in Alzheimer disease (AD) have demonstrated improved clinical efficacy in people with less severe disease. Plasma biomarkers will be essential for efficient screening of participants in future primary prevention clinical trials testing antiamyloid therapies in cognitively unimpaired (CU) individuals with initially low brain beta-amyloid (A beta) levels who are at high risk of accumulating A beta. OBJECTIVE To investigate if combining plasma biomarkers could be useful in predicting subsequent development of A beta pathology in CU individuals with subthreshold brain A beta levels (defined as A beta levels <40 Centiloids) at baseline. DESIGN, SETTING, AND PARTICIPANTS This was a longitudinal study including Swedish BioFINDER-2 (enrollment 2017-2022) and replication in 2 independent cohorts, the Knight Alzheimer Disease Research Center (Knight ADRC; enrollment 1988 and 2019) and Swedish BioFINDER-1 (enrollment 2009-2015). Included for analysis was a convenience sample of CU individuals with baseline plasma phosphorylated tau 217 (p-tau217) and A beta 42/40 assessments and A beta assessments with positron emission tomography (A beta-PET) or cerebrospinal fluid (CSF) A beta 42/40. Data were analyzed between April 2023 and May 2024. EXPOSURES Baseline plasma levels of A beta 42/40, p-tau217, the ratio of p-tau217 to nonphosphorylated tau (%p-tau217), p-tau231, and glial fibrillary acidic protein (GFAP). MAIN OUTCOMES AND MEASURES Cross-sectional and longitudinal PET and CSF measures of brain A beta pathology. RESULTS This study included 495 (BioFINDER-2), 283 (Knight ADRC), and 205 (BioFINDER-1) CU participants. In BioFINDER-2, the mean (SD) age was 65.7 (14.4) with 261 females (52.7%). When detecting abnormal CSF A beta-status, a combination of plasma %p-tau217 and A beta 42/40 showed better performance (area under the curve = 0.949; 95% CI, 0.929-0.970; P <.02) than individual biomarkers. In CU participants with subthreshold baseline A beta-PET, baseline plasma %p-tau217 and A beta 42/40 levels were significantly associated with baseline A beta-PET (n = 384) and increases in A beta-PET over time (n = 224). Associations of plasma %p-tau217 and A beta 42/40 and their interaction with baseline A beta-PET (%p-tau217: beta = 2.77; 95% CI, 1.84-3.70; A beta 42/40: beta = -1.64; 95% CI, -2.53 to -0.75; %p-tau217 x A beta 42/40: beta = -2.14; 95% CI, -2.79 to -1.49; P < .001) and longitudinal A beta-PET (%p-tau217: beta = 0.67; 95% CI, 0.48-0.87; A beta 42/40: beta = -0.33; 95% CI, -0.51 to -0.15; %p-tau217 x A beta 42/40: beta = -0.31; 95% CI, -0.44 to -0.18; P < .001) were also significant in the models combining the 2 baseline biomarkers as predictors. Similarly, baseline plasma p-tau217 and A beta 42/40 were independently associated with longitudinal A beta-PET in Knight ADRC (%p-tau217: beta = 0.71; 95% CI, 0.26-1.16; P = .002; A beta 42/40: beta = -0.74; 95% CI, -1.26 to -0.22; P = .006) and longitudinal CSF A beta 42/40 in BioFINDER-1 (p-tau217: beta = -0.0003; 95% CI, -0.0004 to -0.0001; P = .01; A beta 42/40: beta = 0.0004; 95% CI, 0.0002-0.0006; P < .001) in CU participants with subthreshold A beta levels at baseline. Plasma p-tau231 and GFAP did not provide any clear independent value. CONCLUSIONS AND RELEVANCE Results of this cohort study suggest that combining plasma p-tau217and A beta 42/40 levels could be useful for predicting development of A beta pathology in people with early stages of subthreshold A beta accumulation. These biomarkers might thus facilitate screening of participants for future primary prevention trials.
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| 28. |
- Johansson, Maurits, et al.
(författare)
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Apathy and anxiety are early markers of Alzheimer's disease
- 2020
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 85, s. 74-82
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Tidskriftsartikel (refereegranskat)abstract
- In this study, we investigated associations between neuropsychiatric symptoms (i.e., apathy, anxiety, and depression) and cerebral atrophy, white matter lesions (WML), beta-amyloid (A beta) deposition, and cognitive decline in a nondemented sample. 104 cognitively unimpaired and 53 subjects with mild cognitive impairment were followed for up to 4 years within the Swedish BioFINDER study. Neuropsychiatric assessments included the Hospital Anxiety and Depression Scale and the Apathy Evaluation Scale. Magnetic resonance imaging and F-18-flutemetamol-positron emission tomography quantified brain atrophy, WML, and A beta deposition. Mini-Mental State Examination assessed longitudinal global cognition. Regression analyses were used to test for associations. Apathy and anxiety were shown related to A beta deposition and predicted cognitive decline. Anxiety also interacted with amyloid status to predict faster cognitive deterioration. Apathy was further related to frontotemporal and subcortical atrophy, as well as WML. To conclude, the associations between apathy and anxiety with A beta deposition and cognitive decline point to these symptoms as early clinical manifestations of Alzheimer's disease. (C) 2019 Elsevier Inc. All rights reserved.
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| 29. |
- Leuzy, A., et al.
(författare)
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Robustness of CSF A beta 42/40 and A beta 42/P-tau181 measured using fully automated immunoassays to detect AD-related outcomes
- 2023
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Ingår i: Alzheimers & Dementia. - : Wiley. - 1552-5260 .- 1552-5279. ; 19:7, s. 2994-3004
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Tidskriftsartikel (refereegranskat)abstract
- IntroductionThis study investigated the comparability of cerebrospinal fluid (CSF) cutoffs for Elecsys immunoassays for amyloid beta (A beta)42/A beta 40 or A beta 42/phosphorylated tau (p-tau)181 and the effects of measurement variability when predicting Alzheimer's disease (AD)-related outcomes (i.e., A beta-positron emission tomography [PET] visual read and AD neuropathology). MethodsWe studied 750 participants (BioFINDER study, Alzheimer's Disease Neuroimaging Initiative [ADNI], and University of California San Francisco [UCSF]). Youden's index was used to identify cutoffs and to calculate accuracy (A beta-PET visual read as outcome). Using longitudinal variability in A beta-negative controls, we identified a gray zone around cut-points where the risk of an inconsistent predicted outcome was >5%. ResultsFor A beta 42/A beta 40, cutoffs across cohorts were <0.059 (BioFINDER), <0.057 (ADNI), and <0.058 (UCSF). For A beta 42/p-tau181, cutoffs were <41.90 (BioFINDER), <39.20 (ADNI), and <46.02 (UCSF). Accuracy was approximate to 90% for both A beta 42/A beta 40 and A beta 42/p-tau181 using these cutoffs. Using A beta-PET as an outcome, 8.7% of participants fell within a gray zone interval for A beta 42/A beta 40, compared to 4.5% for A beta 42/p-tau181. Similar findings were observed using a measure of overall AD neuropathologic change (7.7% vs. 3.3%). In a subset with CSF and plasma A beta 42/40, the number of individuals within the gray zone was approximate to 1.5 to 3 times greater when using plasma A beta 42/40. DiscussionCSF A beta 42/p-tau181 was more robust to the effects of measurement variability, suggesting that it may be the preferred Elecsys-based measure in clinical practice and trials.
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| 30. |
- Mattsson-Carlgren, Niklas, et al.
(författare)
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Plasma Biomarker Strategy for Selecting Patients With Alzheimer Disease for Antiamyloid Immunotherapies
- 2024
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Ingår i: JAMA neurology. - 2168-6157 .- 2168-6149. ; 81:1, s. 69-78
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Tidskriftsartikel (refereegranskat)abstract
- Antiamyloid immunotherapies against Alzheimer disease (AD) are emerging. Scalable, cost-effective tools will be needed to identify amyloid β (Aβ)-positive patients without an advanced stage of tau pathology who are most likely to benefit from these therapies. Blood-based biomarkers might reduce the need to use cerebrospinal fluid (CSF) or positron emission tomography (PET) for this.To evaluate plasma biomarkers for identifying Aβ positivity and stage of tau accumulation.The cohort study (BioFINDER-2) was a prospective memory-clinic and population-based study. Participants with cognitive concerns were recruited from 2017 to 2022 and divided into a training set (80% of the data) and test set (20%).Baseline values for plasma phosphorylated tau 181 (p-tau181), p-tau217, p-tau231, N-terminal tau, glial fibrillary acidic protein, and neurofilament light chain.Performance to classify participants by Aβ status (defined by Aβ-PET or CSF Aβ42/40) and tau status (tau PET). Number of hypothetically saved PET scans in a plasma biomarker-guided workflow.Of a total 912 participants, there were 499 males (54.7%) and 413 females (45.3%), and the mean (SD) age was 71.1 (8.49) years. Among the biomarkers, plasma p-tau217 was most strongly associated with Aβ positivity (test-set area under the receiver operating characteristic curve [AUC]=0.94; 95% CI, 0.90-0.97). A 2-cut-point procedure was evaluated, where only participants with ambiguous plasma p-tau217 values (17.1% of the participants in the test set) underwent CSF or PET to assign definitive Aβ status. This procedure had an overall sensitivity of 0.94 (95% CI, 0.90-0.98) and a specificity of 0.86 (95% CI, 0.77-0.95). Next, plasma biomarkers were used to differentiate low-intermediate vs high tau-PET load among Aβ-positive participants. Plasma p-tau217 again performed best, with the test AUC=0.92 (95% CI, 0.86-0.97), without significant improvement when adding any of the other plasma biomarkers. At a false-negative rate less than 10%, the use of plasma p-tau217 could avoid 56.9% of tau-PET scans needed to identify high tau PET among Aβ-positive participants. The results were validated in an independent cohort (n=118).This study found that algorithms using plasma p-tau217 can accurately identify most Aβ-positive individuals, including those likely to have a high tau load who would require confirmatory tau-PET imaging. Plasma p-tau217 measurements may substantially reduce the number of invasive and costly confirmatory tests required to identify individuals who would likely benefit from antiamyloid therapies.
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