Browsing by Subject "Fluid biomarkers"

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    Associations of 18F‐RO‐948 Tau PET with Fluid AD Biomarkers, Centiloid, and Cognition in the Early AD Continuum
    (Wiley, 2025-01-09) Shekari, Mahnaz; González Escalante, Armand; Milà-Alomà, Marta; Falcon, Carles; López-Martos, David; Sánchez-Benavides, Gonzalo; Brugulat-Serrat, Anna; Niñerola-Baizán, Aida; Ashton, Nicholas J.; Karikari, Thomas K.; Lantero Rodriguez, Juan; Snellman, Anniina; Day, Theresa A.; Dage, Jeffrey L.; Ortiz-Romero, Paula; Tonietto, Matteo; Borroni, Edilio; Klein, Gregory; Kollmorgen, Gwendlyn; Quijano-Rubio, Clara; Vanmechelen, Eugeen; Minguillón, Carolina; Fauria, Karine; Perissinotti, Andrés; Molinuevo, Jose Luis; Zetterberg, Henrik; Blennow, Kaj; Grau-Rivera, Oriol; Suárez-Calvet, Marc; Gispert, Juan Domingo; Neurology, School of Medicine
    Background: Fluid biomarkers provide a convenient way to predict AD pathophysiology. However, few studies have focused on determining associations with tau neurofibrillary tangle pathology in the early preclinical AD continuum, relevant to prevention strategies. Methods: Ninety‐nine cognitively unimpaired individuals from the ALFA+ cohort with valid 18F‐RO‐948 and 18F‐flutemetamol PET, T1‐weighted MRI, cognition, CSF, and plasma biomarkers were included. Participants were initially categorized into AT stages using CSF‐based pre‐established cut‐off values [1]. Regional SUVR of 18F‐RO‐948 PET was calculated in entorhinal(BraakI/II), limbic(BraakIII/IV), and neocortical(BraakV/VI) regions using the inferior cerebellum as reference region as well as with the CenTAURz. Regional positivity thresholds per Braak stage were calculated as the median+2SD of the CSF A‐T‐ group. Amyloid PET was quantified using Centiloids. Pearson correlations were calculated between regional 18F‐RO‐948 SUVRs and AD biomarkers. ROC analyses adjusted for age, sex, and APOE‐ε4 performed to evaluate the capacity of biomarkers in predicting BraakI/IIPositive. Four progressive PET‐derived AT groups were defined using Centiloid and tau PET positivity cut‐offs (A‐T‐, AGZT‐, A+T‐ and A+T+; with A‐ CL<12, 12≤AGZ<38 and A+ CL≥38 [2], and T+ BraakI/II>1.35) and between‐stage differences in z‐scored biomarkers evaluated using a Kruskal‐Wallis tests. Results: Table 1 shows demographic information of participants. Nine(9.09%) participants were BraakI/IIPositive, seven(7.07%) BraakIII/IVPositive and one(1.01%) BraakV/VIPositive. Two BraakIII/IVPositive participants were BraakI/IINegative, deviating from the Braak hierarchical model. CSF biomarker correlations with BraakI/II SUVR (Figure 1‐A) ranged from r=0.24(ttau) to r=0.57(ptau217) and plasma (Figure 1‐B) from r=0.30(ptau217) to r=0.49(ptau181). Correlations survived adding age+sex+APOE‐ε4 in the model (Figure 1‐C&D). CSF ptau181/Aβ42, ptau217 and ptau205 showed an AUC≥0.93 to predict BraakI/IIPositive, and plasma ptau181, ptau181/Aβ42 and ptau217 had an AUC≥0.84. Centiloid positivity threshold for BraakI/IIPositive was 38.14CL. Plasma ptau181, ptau181/Aβ42, and CSF ptau205, ptau217, and ptau235 reached a mean z‐score>2 for the PET‐derived A+T+ group (Figure 2) which was associated with lower cognitive scores for executive function (p=0.03), attention (p=0.05), and the PACC (p=0.01). Conclusion: 18F‐RO‐948 PET conformed to the Braak hierarchical model for most tau‐positive participants. Fluid AD biomarkers showed moderate associations with tau PET SUVR. Plasma biomarkers showed good capacity to predict BraakI/IIPositive and track fibrillary amyloid and tau pathological changes in the early preclinical AD continuum.
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    Blood-based biomarkers for Alzheimer's disease and related dementias: Keys to success and things to consider
    (Elsevier, 2019-11-14) Zetterberg, Henrik; Apostolova, Liana G.; Snyder, Peter J.; Radiology and Imaging Sciences, School of Medicine
    During the last two decades, considerable progress has been made in the field of fluid and imaging biomarkers for neurodegenerative dementias. As a result, the most recent research and clinical guidelines (the National Institute on Aging and Alzheimer's Association, International Working Group 2, National Institute for Health and Care Excellence) incorporate cerebrospinal fluid (CSF) and positron emission tomography (PET) biomarkers in the diagnostic criteria of dementia and mild cognitive impairment due to Alzheimer's disease (AD) [[1], [2], [3]]. However, as both CSF and amyloid PET examinations require expert knowledge and are of limited availability outside specialized memory clinics, there is no doubt that blood tests would be much easier to implement in clinical medicine and as screening tools when recruiting patients for clinical trials.
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    Clinical and neuropathological associations of plasma Aβ42/Aβ40, p‐tau217 and neurofilament light in sporadic frontotemporal dementia spectrum disorders
    (Wiley, 2025-01-29) Rajbanshi, Binita; Araujo, Igor Prufer Q. C.; VandeVrede, Lawren; Ljubenkov, Peter A.; Staffaroni, Adam M.; Heuer, Hilary W.; Lago, Argentina Lario; Ramos, Eliana Marisa; Petrucelli, Leonard; Gendron, Tania; Dage, Jeffrey L.; Seeley, William W.; Grinberg, Lea T.; Spina, Salvatore; Bateman, Randall J.; Rosen, Howard J.; Boeve, Bradley F.; Boxer, Adam L.; Rojas, Julio C.; ALLFTD Consortium; Neurology, School of Medicine
    Introduction: Plasma amyloid beta42/amyloid beta40 (Aβ42/Aβ40) and phosphorylated tau217 (p-tau217) identify individuals with primary Alzheimer's disease (AD). They may detect AD co-pathology in the setting of other primary neurodegenerative diseases, but this has not been systematically studied. Methods: We compared the clinical, neuroimaging, and neuropathological associations of plasma Aβ42/Aβ40 (mass spectrometry), p-tau217 (electrochemiluminescence), and neurofilament light ([NfL], single molecule array [Simoa]), as markers of AD co-pathology, in a sporadic frontotemporal dementia (FTD) cohort (n = 620). Results: Aβ42/Aβ40 showed no clinicopathological associations. High p-tau217 was present in amnestic dementia (AmD) presumed to be due to FTD, logopenic primary progressive aphasia (lvPPA), and APOEε4 carriers, and correlated with worse baseline and longitudinal clinical scores, lower hippocampal volumes, and more severe AD co-pathology (Braak Stage). NfL was elevated in all FTD phenotypes, and correlated with clinical scores and frontotemporal brain volumes. Discussion: Plasma p-tau217 has clinical, neuroimaging, and neuropathological correlates in sporadic FTD and may identify FTD cases with AD co-pathology. Highlights: Alzheimer's disease (AD) features could be identified with plasma phosphorylated tau217 (p-tau217) in frontotemporal lobar degeneration (FTLD).Plasma p-tau217 is a better discriminator of AD co-pathology and AD-associated features in FTLD than plasma amyloid beta42/amyloid beta40 (Aβ42/Aβ40) and neurofilament light (NfL).In FTLD, plasma p-tau217, but not Aβ42/Aβ40 or neurofilament light, has phenotypical, neurocognitive, and neuroimaging correlates suggestive of AD co-pathology.
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    Genetic variation affecting exon skipping contributes to brain structural atrophy in Alzheimer's disease
    (American Medical Informatics Association, 2018-05-18) Lee, Younghee; Han, Seonggyun; Kim, Dongwook; Kim, Dokyoon; Horgousluoglu, Emrin; Risacher, Shannon L.; Saykin, Andrew J.; Nho, Kwangsik; Alzheimer’s Disease Neuroimaging Initiative; Radiology and Imaging Sciences, School of Medicine
    Genetic variation in cis-regulatory elements related to splicing machinery and splicing regulatory elements (SREs) results in exon skipping and undesired protein products. We developed a splicing decision model to identify actionable loci among common SNPs for gene regulation. The splicing decision model identified SNPs affecting exon skipping by analyzing sequence-driven alternative splicing (AS) models and by scanning the genome for the regions with putative SRE motifs. We used non-Hispanic Caucasians with neuroimaging, and fluid biomarkers for Alzheimer's disease (AD) and identified 17,088 common exonic SNPs affecting exon skipping. GWAS identified one SNP (rs1140317) in HLA-DQB1 as significantly associated with entorhinal cortical thickness, AD neuroimaging biomarker, after controlling for multiple testing. Further analysis revealed that rs1140317 was significantly associated with brain amyloid-f deposition (PET and CSF). HLA-DQB1 is an essential immune gene and may regulate AS, thereby contributing to AD pathology. SRE may hold potential as novel therapeutic targets for AD.