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- Wang, Li-San, et al.
(author)
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Rarity of the Alzheimer Disease-Protective APP A673T Variant in the United States.
- 2015
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In: JAMA neurology. - : American Medical Association (AMA). - 2168-6157 .- 2168-6149. ; 72:2
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Journal article (peer-reviewed)abstract
- Recently, a rare variant in the amyloid precursor protein gene (APP) was described in a population from Iceland. This variant, in which alanine is replaced by threonine at position 673 (A673T), appears to protect against late-onset Alzheimer disease (AD). We evaluated the frequency of this variant in AD cases and cognitively normal controls to determine whether this variant will significantly contribute to risk assessment in individuals in the United States.
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- Aalbers, J., et al.
(author)
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A next-generation liquid xenon observatory for dark matter and neutrino physics
- 2023
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In: Journal of Physics G: Nuclear and Particle Physics. - : IOP Publishing. - 0954-3899 .- 1361-6471. ; 50:1
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Research review (peer-reviewed)abstract
- The nature of dark matter and properties of neutrinos are among the most pressing issues in contemporary particle physics. The dual-phase xenon time-projection chamber is the leading technology to cover the available parameter space for weakly interacting massive particles, while featuring extensive sensitivity to many alternative dark matter candidates. These detectors can also study neutrinos through neutrinoless double-beta decay and through a variety of astrophysical sources. A next-generation xenon-based detector will therefore be a true multi-purpose observatory to significantly advance particle physics, nuclear physics, astrophysics, solar physics, and cosmology. This review article presents the science cases for such a detector.
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- Casaletto, K. B., et al.
(author)
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A comparison of biofluid cytokine markers across platform technologies: Correspondence or divergence?
- 2018
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In: Cytokine. - : Elsevier BV. - 1043-4666. ; 111, s. 481-489
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Journal article (peer-reviewed)abstract
- Background: Quantification of biofluid cytokines is a rapidly growing area of translational research. However, comparability across the expanding number of available assay platforms for detection of the same proteins remains to be determined. We aimed to directly compare a panel of commonly measured cytokines in plasma of typically aging adults across two high sensitivity quantification platforms, Meso Scale Discovery high performance electrochemiluminiscence (HPE) and single-molecule immunosorbent assays (Simoa) by Quanterix. Methods: 57 community-dwelling older adults completed a blood draw, neuropsychological assessment, and brain MRI as part of a healthy brain aging study. Plasma samples from the same draw dates were analyzed for IL-10, IP-10, IL-6, TNF alpha, and IL-1 beta on HPE and Simoa, separately. Reliable detectability (coefficient of variance (CV) < 20% and outliers 3 interquartiles above the median removed), intra-assay precision, absolute concentrations, reproducibility across platforms, and concurrent associations with external variables of interest (e.g., demographics, peripheral markers of vascular health, and brain health) were examined. Results: The proportion of cytokines reliably measured on HPE (87.7-93.0%) and Simoa (75.4-93.0%) did not differ (ps > 0.32), with the exception of IL-1 beta which was only reliably measured using Simoa (68.4%). On average, CVs were acceptable at < 8% across both platforms. Absolute measured concentrations were higher using Simoa for IL-10, IL-6, and TNF alpha (ps < 0.05). HPE and Simoa shared only small-to-moderate proportions of variance with one another on the same cytokine proteins (range: r = 0.26 for IL-10 to r = 0.64 for IL-6), though platform agreement did not dependent on cytokine concentrations. Cytokine ratios within each platform demonstrated similar relative patterns of up- and down-regulation across HPE and Simoa, though still significantly differed (ps < 0.001). Supporting concurrent validity, all 95% confidence intervals of the correlations between cytokines and external variables overlapped between the two platforms. Moreover, most associations were in expected directions and consistently so across platforms (e.g., IL-6 and TNF alpha), though with several notable exceptions for IP-10 and IL-10. Conclusions: HPE and Simoa showed comparable detectability and intra-assay precision measuring a panel of commonly examined cytokine proteins, with the exception of IL-1 beta which was not reliably detected on HPE. However, Simoa demonstrated overall higher concentrations and the two platforms did not show agreement when directly compared against one another. Relative cytokine ratios and associations demonstrated similar patterns across platforms. Absolute cytokine concentrations may not be directly comparable across platforms, may be analyte dependent, and interpretation may be best limited to discussion of relative associations.
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- Thijssen, E. H., et al.
(author)
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Diagnostic value of plasma phosphorylated tau181 in Alzheimer's disease and frontotemporal lobar degeneration
- 2020
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In: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 26, s. 387-397
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Journal article (peer-reviewed)abstract
- Plasma pTau181 concentrations are elevated specifically in patients diagnosed with Alzheimer's disease compared to those diagnosed with frontotemporal lobar degeneration or elderly controls, supporting its further development as a blood-based biomarker for AD. With the potential development of new disease-modifying Alzheimer's disease (AD) therapies, simple, widely available screening tests are needed to identify which individuals, who are experiencing symptoms of cognitive or behavioral decline, should be further evaluated for initiation of treatment. A blood-based test for AD would be a less invasive and less expensive screening tool than the currently approved cerebrospinal fluid or amyloid beta positron emission tomography (PET) diagnostic tests. We examined whether plasma tau phosphorylated at residue 181 (pTau181) could differentiate between clinically diagnosed or autopsy-confirmed AD and frontotemporal lobar degeneration. Plasma pTau181 concentrations were increased by 3.5-fold in AD compared to controls and differentiated AD from both clinically diagnosed (receiver operating characteristic area under the curve of 0.894) and autopsy-confirmed frontotemporal lobar degeneration (area under the curve of 0.878). Plasma pTau181 identified individuals who were amyloid beta-PET-positive regardless of clinical diagnosis and correlated with cortical tau protein deposition measured by F-18-flortaucipir PET. Plasma pTau181 may be useful to screen for tau pathology associated with AD.
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- Chen, J., et al.
(author)
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Genome-wide association study identifies MAPT locus influencing human plasma tau levels
- 2017
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 88:7, s. 669-676
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Journal article (peer-reviewed)abstract
- Objective: To identify genetic loci associated with plasma tau concentrations in healthy elders and individuals with Alzheimer disease. Methods: Four hundred sixty-three non-Hispanic white individuals exceeding quality control criteria were included from the Alzheimer's Disease Neuroimaging Initiative (ADNI-1) cohort. Association of plasma tau with genetic polymorphisms was performed with a linear regression model. Significant associations were validated in an independent replication cohort consisting of 431 healthy elders or individuals with mild cognitive impairment recruited from the University of California, San Francisco Memory and Aging Center. Results: The minor allele (A) of rs242557 in the microtubule-associated protein tau gene (MAPT) was associated with higher plasma tau levels at genome-wide significance (p = 4.85 x 10(-9), empiric family-wise error corrected p = 0.0024) in a dose-dependent fashion. This association was also observed in the replication cohort (p = 1.0 x 10(-5); joint analysis p = 1.2 x 10(-12)). Single nucleotide polymorphisms near PARK2 (rs2187213) (p = 6.15 x 10(-6)), IL2RA (rs7072793, rs7073236) (p = 7.89 x 10(-6)), and an intergenic locus on 9p21.3 (rs7047280) (p = 8.13 x 10(-6)) were identified as suggestive loci associated with plasma tau levels. Conclusions: MAPT H1c haplotype (rs242557) has previously been identified as a genetic risk factor for progressive supranuclear palsy and corticobasal degeneration. The current findings suggest that plasma tau concentration could be an endophenotype for identifying risk for 4-repeat tauopathies in older individuals.
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- Grossman, M., et al.
(author)
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Frontotemporal lobar degeneration
- 2023
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In: Nature Reviews Disease Primers. - 2056-676X. ; 9:1
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Journal article (peer-reviewed)abstract
- Frontotemporal lobar degeneration (FTLD) is one of the most common causes of early-onset dementia and presents with early social-emotional-behavioural and/or language changes that can be accompanied by a pyramidal or extrapyramidal motor disorder. About 20-25% of individuals with FTLD are estimated to carry a mutation associated with a specific FTLD pathology. The discovery of these mutations has led to important advances in potentially disease-modifying treatments that aim to slow progression or delay disease onset and has improved understanding of brain functioning. In both mutation carriers and those with sporadic disease, the most common underlying diagnoses are linked to neuronal and glial inclusions containing tau (FTLD-tau) or TDP-43 (FTLD-TDP), although 5-10% of patients may have inclusions containing proteins from the FUS-Ewing sarcoma-TAF15 family (FTLD-FET). Biomarkers definitively identifying specific pathological entities in sporadic disease have been elusive, which has impeded development of disease-modifying treatments. Nevertheless, disease-monitoring biofluid and imaging biomarkers are becoming increasingly sophisticated and are likely to serve as useful measures of treatment response during trials of disease-modifying treatments. Symptomatic trials using novel approaches such as transcranial direct current stimulation are also beginning to show promise. Frontotemporal lobar degeneration is one of the most common causes of early-onset dementia. This Primer summarizes the epidemiology, pathophysiology, diagnosis, and treatment of frontotemporal dementia and discusses how this disorder affects patients' quality of life.
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- Höglinger, Günter U, et al.
(author)
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Clinical diagnosis of progressive supranuclear palsy : The movement disorder society criteria
- 2017
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In: Movement Disorders. - : Wiley. - 0885-3185. ; 32:6, s. 853-864
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Journal article (peer-reviewed)abstract
- Background: PSP is a neuropathologically defined disease entity. Clinical diagnostic criteria, published in 1996 by the National Institute of Neurological Disorders and Stroke/Society for PSP, have excellent specificity, but their sensitivity is limited for variant PSP syndromes with presentations other than Richardson's syndrome. Objective: We aimed to provide an evidence- and consensus-based revision of the clinical diagnostic criteria for PSP. Methods: We searched the PubMed, Cochrane, Medline, and PSYCInfo databases for articles published in English since 1996, using postmortem diagnosis or highly specific clinical criteria as the diagnostic standard. Second, we generated retrospective standardized clinical data from patients with autopsy-confirmed PSP and control diseases. On this basis, diagnostic criteria were drafted, optimized in two modified Delphi evaluations, submitted to structured discussions with consensus procedures during a 2-day meeting, and refined in three further Delphi rounds. Results: Defined clinical, imaging, laboratory, and genetic findings serve as mandatory basic features, mandatory exclusion criteria, or context-dependent exclusion criteria. We identified four functional domains (ocular motor dysfunction, postural instability, akinesia, and cognitive dysfunction) as clinical predictors of PSP. Within each of these domains, we propose three clinical features that contribute different levels of diagnostic certainty. Specific combinations of these features define the diagnostic criteria, stratified by three degrees of diagnostic certainty (probable PSP, possible PSP, and suggestive of PSP). Clinical clues and imaging findings represent supportive features. Conclusions: Here, we present new criteria aimed to optimize early, sensitive, and specific clinical diagnosis of PSP on the basis of currently available evidence.
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- Ossenkoppele, Rik, et al.
(author)
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Discriminative Accuracy of F-18 flortaucipir Positron Emission Tomography for Alzheimer Disease vs Other Neurodegenerative Disorders
- 2018
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In: Jama-Journal of the American Medical Association. - : American Medical Association (AMA). - 0098-7484. ; 320:11, s. 1151-1162
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Journal article (peer-reviewed)abstract
- IMPORTANCE The positron emission tomography (PET) tracer [F-18]flortaucipir allows in vivo quantification of paired helical filament tau, a core neuropathological feature of Alzheimer disease (AD), but its diagnostic utility is unclear. OBJECTIVE To examine the discriminative accuracy of [F-18]flortaucipir for AD vs non-AD neurodegenerative disorders. DESIGN, SETTING, AND PARTICIPANTS In this cross-sectional study, 719 participants were recruited from 3 dementia centers in South Korea, Sweden, and the United States between June 2014 and November 2017 (160 cognitively normal controls, 126 patients with mild cognitive impairment [MCI], of whom 65.9% were amyloid-beta [A beta]positive [ie, MCI due to AD], 179 patients with AD dementia, and 254 patients with various non-AD neurodegenerative disorders). EXPOSURES The index testwas the [F-18]flortaucipir PET standardized uptake value ratio (SUVR) in 5 predefined regions of interest (ROIs). Cut points for tau positivity were determined using the mean +2 SDs observed in controls and Youden Index for the contrast AD dementia vs controls. MAIN OUTCOMES AND MEASURES The reference standard was the clinical diagnosis determined at the specialized memory centers. In the primary analysis, the discriminative accuracy (ie, sensitivity and specificity) of [F-18]flortaucipir was examined for AD dementia vs all non-AD neurodegenerative disorders. In secondary analyses, the area under the curve (AUC) of [F-18]flortaucipir SUVR was compared with 3 established magnetic resonance imaging measures (hippocampal volumes and AD signature and whole-brain cortical thickness), and sensitivity and specificity of [F-18]flortaucipir in MCI due to AD vs non-AD neurodegenerative disorders were determined. RESULTS Among 719 participants, the overall mean (SD) age was 68.8 (9.2) years and 48.4% were male. The proportions of patients who were amyloid-beta positive were 26.3%, 65.9%, 100%, and 23.8% among cognitively normal controls, patients with MCI, patients with AD dementia, and patients with non-AD neurodegenerative disorders, respectively. [F-18]flortaucipir uptake in the medial-basal and lateral temporal cortex showed 89.9% (95% CI, 84.6%-93.9%) sensitivity and 90.6%(95% CI, 86.3%-93.9%) specificity using the threshold based on controls (SUVR, 1.34), and 96.8%(95% CI, 92.0%-99.1%) sensitivity and 87.9%(95% CI, 81.9%-92.4%) specificity using the Youden Index-derived cutoff (SUVR, 1.27) for distinguishing AD dementia from all non-AD neurodegenerative disorders. The AUCs for all 5 [F-18]flortaucipir ROIs were higher (AUC range, 0.92-0.95) compared with the 3 volumetric MRI measures (AUC range, 0.63-0.75; all ROIs P<.001). Diagnostic performance of the 5 [F-18]flortaucipir ROIs were lower in MCI due to AD (AUC range, 0.75-0.84). CONCLUSIONS AND RELEVANCE Among patients with established diagnoses at a memory disorder clinic, [F-18]flortaucipir PET was able to discriminate AD from other neurodegenerative diseases. The accuracy and potential utility of this test in patient care require further research in clinically more representative populations.
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- Respondek, Gesine, et al.
(author)
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Which ante mortem clinical features predict progressive supranuclear palsy pathology?
- 2017
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In: Movement Disorders. - : Wiley. - 0885-3185. ; 32:7, s. 995-1005
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Research review (peer-reviewed)abstract
- Background: Progressive supranuclear palsy (PSP) is a neuropathologically defined disease presenting with a broad spectrum of clinical phenotypes. Objective: To identify clinical features and investigations that predict or exclude PSP pathology during life, aiming at an optimization of the clinical diagnostic criteria for PSP. Methods: We performed a systematic review of the literature published since 1996 to identify clinical features and investigations that may predict or exclude PSP pathology. We then extracted standardized data from clinical charts of patients with pathologically diagnosed PSP and relevant disease controls and calculated the sensitivity, specificity, and positive predictive value of key clinical features for PSP in this cohort. Results: Of 4166 articles identified by the database inquiry, 269 met predefined standards. The literature review identified clinical features predictive of PSP, including features of the following 4 functional domains: ocular motor dysfunction, postural instability, akinesia, and cognitive dysfunction. No biomarker or genetic feature was found reliably validated to predict definite PSP. High-quality original natural history data were available from 206 patients with pathologically diagnosed PSP and from 231 pathologically diagnosed disease controls (54 corticobasal degeneration, 51 multiple system atrophy with predominant parkinsonism, 53 Parkinson's disease, 73 behavioral variant frontotemporal dementia). We identified clinical features that predicted PSP pathology, including phenotypes other than Richardson's syndrome, with varying sensitivity and specificity. Conclusions: Our results highlight the clinical variability of PSP and the high prevalence of phenotypes other than Richardson's syndrome. The features of variant phenotypes with high specificity and sensitivity should serve to optimize clinical diagnosis of PSP.
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- Schneider, R, et al.
(author)
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Downregulation of exosomal miR-204-5p and miR-632 as a biomarker for FTD: a GENFI study
- 2018
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In: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 89:8, s. 851-858
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Journal article (peer-reviewed)abstract
- To determine whether exosomal microRNAs (miRNAs) in cerebrospinal fluid (CSF) of patients with frontotemporal dementia (FTD) can serve as diagnostic biomarkers, we assessed miRNA expression in the Genetic Frontotemporal Dementia Initiative (GENFI) cohort and in sporadic FTD.MethodsGENFI participants were either carriers of a pathogenic mutation in progranulin, chromosome 9 open reading frame 72 or microtubule-associated protein tau or were at risk of carrying a mutation because a first-degree relative was a known symptomatic mutation carrier. Exosomes were isolated from CSF of 23 presymptomatic and 15 symptomatic mutation carriers and 11 healthy non-mutation carriers. Expression of 752 miRNAs was measured using quantitative PCR (qPCR) arrays and validated by qPCR using individual primers. MiRNAs found differentially expressed in symptomatic compared with presymptomatic mutation carriers were further evaluated in a cohort of 17 patients with sporadic FTD, 13 patients with sporadic Alzheimer’s disease (AD) and 10 healthy controls (HCs) of similar age.ResultsIn the GENFI cohort, miR-204-5p and miR-632 were significantly decreased in symptomatic compared with presymptomatic mutation carriers. Decrease of miR-204-5p and miR-632 revealed receiver operator characteristics with an area of 0.89 (90% CI 0.79 to 0.98) and 0.81 (90% CI 0.68 to 0.93), respectively, and when combined an area of 0.93 (90% CI 0.87 to 0.99). In sporadic FTD, only miR-632 was significantly decreased compared with AD and HCs. Decrease of miR-632 revealed an area of 0.90 (90% CI 0.81 to 0.98).ConclusionsExosomal miR-204-5p and miR-632 have potential as diagnostic biomarkers for genetic FTD and miR-632 also for sporadic FTD.
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- Zalm, P. W. V., et al.
(author)
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Article Meta-analysis of published cerebrospinal fluid proteomics data identifies and validates metabolic enzyme panel as Alzheimer's disease biomarkers
- 2023
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In: Cell Reports Medicine. - 2666-3791. ; 4:4
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Journal article (peer-reviewed)abstract
- To develop therapies for Alzheimer's disease, we need accurate in vivo diagnostics. Multiple proteomic studies mapping biomarker candidates in cerebrospinal fluid (CSF) resulted in little overlap. To overcome this shortcoming, we apply the rarely used concept of proteomics meta-analysis to identify an effective biomarker panel. We combine ten independent datasets for biomarker identification: seven datasets from 150 patients/controls for discovery, one dataset with 20 patients/controls for down-selection, and two data -sets with 494 patients/controls for validation. The discovery results in 21 biomarker candidates and down -selection in three, to be validated in the two additional large-scale proteomics datasets with 228 diseased and 266 control samples. This resulting 3-protein biomarker panel differentiates Alzheimer's disease (AD) from controls in the two validation cohorts with areas under the receiver operating characteristic curve (AUROCs) of 0.83 and 0.87, respectively. This study highlights the value of systematically re-analyzing pre-viously published proteomics data and the need for more stringent data deposition.
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