Browsing by Subject "Amyloid beta"
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Item Alzheimer's disease and inflammatory biomarkers positively correlate in plasma in the UK‐ADRC cohort(Wiley, 2024) Foley, Kate E.; Winder, Zachary; Sudduth, Tiffany L.; Martin, Barbara J.; Nelson, Peter T.; Jicha, Gregory A.; Harp, Jordan P.; Weekman, Erica M.; Wilcock, Donna M.; Neurology, School of MedicineIntroduction: Protein-based plasma assays provide hope for improving accessibility and specificity of molecular diagnostics to diagnose dementia. Methods: Plasma was obtained from participants (N = 837) in our community-based University of Kentucky Alzheimer's Disease Research Center cohort. We evaluated six Alzheimer's disease (AD)- and neurodegeneration-related (Aβ40, Aβ42, Aβ42/40, p-tau181, total tau, and NfLight) and five inflammatory biomarkers (TNF𝛼, IL6, IL8, IL10, and GFAP) using the SIMOA-based protein assay platform. Statistics were performed to assess correlations. Results: Our large cohort reflects previous plasma biomarker findings. Relationships between biomarkers to understand AD-inflammatory biomarker correlations showed significant associations between AD and inflammatory biomarkers suggesting peripheral inflammatory interactions with increasing AD pathology. Biomarker associations parsed out by clinical diagnosis (normal, MCI, and dementia) reveal changes in strength of the correlations across the cognitive continuum. Discussion: Unique AD-inflammatory biomarker correlations in a community-based cohort reveal a new avenue for utilizing plasma-based biomarkers in the assessment of AD and related dementias. Highlights: Large community cohorts studying sex, age, and APOE genotype effects on biomarkers are few. It is unknown how biomarker-biomarker associations vary through aging and dementia. Six AD (Aβ40, Aβ42, Aβ42/40, p-tau181, total tau, and NfLight) and five inflammatory biomarkers (TNFα, IL6, IL8, IL10, and GFAP) were used to examine associations between biomarkers. Plasma biomarkers suggesting increasing cerebral AD pathology corresponded to increases in peripheral inflammatory markers, both pro-inflammatory and anti-inflammatory. Strength of correlations, between pairs of classic AD and inflammatory plasma biomarker, changes throughout cognitive progression to dementia.Item 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(Wiley, 2022) Verberk, Inge M. W.; Misdorp, Els O.; Koelewijn, Jannet; Ball, Andrew J.; Blennow, Kaj; Dage, Jeffrey L.; Fandos, Noelia; Hansson, Oskar; Hirtz, Christophe; Janelidze, Shorena; Kang, Sungmin; Kirmess, Kristopher; Kindermans, Jana; Lee, Ryan; Meyer, Matthew R.; Shan, Dandan; Shaw, Leslie M.; Waligorska, Teresa; West, Tim; Zetterberg, Henrik; Edelmayer, Rebecca M.; Teunissen, Charlotte E.; Neurology, School of MedicineIntroduction: 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.Item Contribution of Alzheimer's biomarkers and risk factors to cognitive impairment and decline across the Alzheimer's disease continuum(Wiley, 2022) Tosun, Duygu; Demir, Zeynep; Veitch, Dallas P.; Weintraub, Daniel; Aisen, Paul; Jack, Clifford R., Jr.; Jagust, William J.; Petersen, Ronald C.; Saykin, Andrew J.; Shaw, Leslie M.; Trojanowski, John Q.; Weiner, Michael W.; Alzheimer’s Disease Neuroimaging Initiative; Radiology and Imaging Sciences, School of MedicineIntroduction: Amyloid beta (Aβ), tau, and neurodegeneration jointly with the Alzheimer's disease (AD) risk factors affect the severity of clinical symptoms and disease progression. Methods: Within 248 Aβ-positive elderly with and without cognitive impairment and dementia, partial least squares structural equation pathway modeling was used to assess the direct and indirect effects of imaging biomarkers (global Aβ-positron emission tomography [PET] uptake, regional tau-PET uptake, and regional magnetic resonance imaging-based atrophy) and risk-factors (age, sex, education, apolipoprotein E [APOE], and white-matter lesions) on cross-sectional cognitive impairment and longitudinal cognitive decline. Results: Sixteen percent of variance in cross-sectional cognitive impairment was accounted for by Aβ, 46% to 47% by tau, and 25% to 29% by atrophy, although 53% to 58% of total variance in cognitive impairment was explained by incorporating mediated and direct effects of AD risk factors. The Aβ-tau-atrophy pathway accounted for 50% to 56% of variance in longitudinal cognitive decline while Aβ, tau, and atrophy independently explained 16%, 46% to 47%, and 25% to 29% of the variance, respectively. Discussion: These findings emphasize that treatments that remove Aβ and completely stop downstream effects on tau and neurodegeneration would only be partially effective in slowing of cognitive decline or reversing cognitive impairment.Item Correction to: Multidimensional insights into the repeated electromagnetic field stimulation and biosystems interaction in aging and age-related diseases(BMC, 2022-09-09) Perez, Felipe P.; Bandeira, Joseph P.; Perez Chumbiauca, Cristina N.; Lahiri, Debomoy K.; Morisaki, Jorge; Rizkalla, Maher; Medicine, School of MedicineCorrection to: Journal of Biomedical Science (2022) 29:39 https://doi.org/10.1186/s12929-022-00825-yItem Genome-wide transcriptome analysis of Aβ deposition on PET in a Korean cohort(Wiley, 2024) Park, Tamina; Hwang, Jiyun; Liu, Shiwei; Chaudhuri, Soumilee; Han, Sang Won; Yi, Dahyun; Byun, Min Soo; Huang, Yen-Ning; Rosewood, Thea; Jung, Gijung; Kim, Min Jeong; Ahn, Hyejin; Lee, Jun-Young; Kim, Yu Kyeong; Cho, MinYoung; Bice, Paula J.; Craft, Hannah; Risacher, Shannon L.; Gao, Hongyu; Liu, Yunlong; Kim, SangYun; Park, Young Ho; Lee, Dong Young; Saykin, Andrew J.; Nho, Kwangsik; Radiology and Imaging Sciences, School of MedicineIntroduction: Despite the recognized importance of including ethnic diversity in Alzheimer's disease (AD) research, substantial knowledge gaps remain, particularly in Asian populations. Methods: RNA sequencing was performed on blood samples from the Korean Brain Aging Study for the Early Diagnosis and Prediction of Alzheimer's Disease (KBASE) to perform differential gene expression (DGE), gene co-expression network, gene-set enrichment, and machine learning analyses for amyloid beta (Aβ) deposition on positron emission tomography. Results: DGE analysis identified 265 dysregulated genes associated with Aβ deposition and replicated three AD-associated genes in an independent Korean cohort. Network analysis identified two modules related to pathways including a natural killer (NK) cell-mediated immunity. Machine learning analysis showed the classification of Aβ positivity improved with the inclusion of gene expression data. Discussion: Our results in a Korean population suggest Aβ deposition-associated genes are enriched in NK cell-mediated immunity, providing a better understanding of AD molecular mechanisms and yielding potential diagnostic and therapeutic strategies. Highlights: Dysregulated genes were associated with amyloid beta (Aβ) deposition on positron emission tomography in a Korean cohort. Dysregulated genes in Alzheimer's disease were replicated in an independent Korean cohort. Gene network modules were associated with Aβ deposition. Natural killer (NK) cell proportion in blood was associated with Aβ deposition. Dysregulated genes were related to a NK cell-mediated immunity.Item Identifying genetic variants for amyloid β in subcortical vascular cognitive impairment(Frontiers Media, 2023-04-18) Kim, Hang-Rai; Jung, Sang-Hyuk; Kim, Beomsu; Kim, Jaeho; Jang, Hyemin; Kim, Jun Pyo; Kim, So Yeon; Na, Duk L.; Kim, Hee Jin; Nho, Kwangsik; Won, Hong-Hee; Seo, Sang Won; Alzheimer’s Disease Neuroimaging Initiative; Radiology and Imaging Sciences, School of MedicineBackground: The genetic basis of amyloid β (Aβ) deposition in subcortical vascular cognitive impairment (SVCI) is still unknown. Here, we investigated genetic variants involved in Aβ deposition in patients with SVCI. Methods: We recruited a total of 110 patients with SVCI and 424 patients with Alzheimer's disease-related cognitive impairment (ADCI), who underwent Aβ positron emission tomography and genetic testing. Using candidate AD-associated single nucleotide polymorphisms (SNPs) that were previously identified, we investigated Aβ-associated SNPs that were shared or distinct between patients with SVCI and those with ADCI. Replication analyses were performed using the Alzheimer's Disease Neuroimaging Initiative (ADNI) and Religious Orders Study and Rush Memory and Aging Project cohorts (ROS/MAP). Results: We identified a novel SNP, rs4732728, which showed distinct associations with Aβ positivity in patients with SVCI (P interaction = 1.49 × 10-5); rs4732728 was associated with increased Aβ positivity in SVCI but decreased Aβ positivity in ADCI. This pattern was also observed in ADNI and ROS/MAP cohorts. Prediction performance for Aβ positivity in patients with SVCI increased (area under the receiver operating characteristic curve = 0.780; 95% confidence interval = 0.757-0.803) when rs4732728 was included. Cis-expression quantitative trait loci analysis demonstrated that rs4732728 was associated with EPHX2 expression in the brain (normalized effect size = -0.182, P = 0.005). Conclusion: The novel genetic variants associated with EPHX2 showed a distinct effect on Aβ deposition between SVCI and ADCI. This finding may provide a potential pre-screening marker for Aβ positivity and a candidate therapeutic target for SVCI.Item Locus coeruleus tau is linked to successive cortical tau accumulation(Wiley, 2025) Yi, Dahyun; Byun, Min Soo; Jung, Joon Hyung; Jung, Gijung; Ahn, Hyejin; Chang, Yoon Young; Keum, Musung; Lee, Jun-Young; Lee, Yun-Sang; Kim, Yu Kyeong; Kang, Koung Mi; Sohn, Chul-Ho; Risacher, Shannon L.; Saykin, Andrew J.; Lee, Dong Young; KBASE Research Group; Radiology and Imaging Sciences, School of MedicineIntroduction: We investigated the hypothesis that tau burden in the locus coeruleus (LC) correlates with tau accumulation in cortical regions according to the Braak stages and examined whether the relationships differed according to cortical amyloid beta (Aβ) deposition. Methods: One hundred and seventy well-characterized participants from an ongoing cohort were included. High-resolution T1, tau positron emission tomography (PET), and amyloid PET were obtained. Results: LC tau burden was significantly linked to global tau in neocortical regions, as was tau in both early Braak stage (stage I/II) and later Braak stage areas. This relationship was significant only in Aβ-positive individuals. While LC tau did not directly impact memory, it was indirectly associated with delayed memory through mediation or moderation pathways. Discussion: The findings from living human brains support the idea that LC tau closely relates to subsequent cortical tau accumulation, particularly among individuals with pathological Aβ accumulation, and identify LC tau burden as a promising indicator of cognitive trajectories of AD. Highlights: Tau burden in the LC was significantly associated with cortical tau accumulation. Tau burden in SN or PPN showed no association with cortical tau accumulation. LC tau burden was serially associated with Braak stages. The tau-LC and cortical tau relationship was significant only in the Aβ-positive group. Cortical amyloid's impact on memory worsens with higher tau accumulation in the LC.Item Multidimensional insights into the repeated electromagnetic field stimulation and biosystems interaction in aging and age-related diseases(BMC, 2022-06-13) Perez, Felipe P.; Bandeira, Joseph P.; Perez Chumbiauca, Cristina N.; Lahiri, Debomoy K.; Morisaki, Jorge; Rizkalla, Maher; Medicine, School of MedicineWe provide a multidimensional sequence of events that describe the electromagnetic field (EMF) stimulation and biological system interaction. We describe this process from the quantum to the molecular, cellular, and organismal levels. We hypothesized that the sequence of events of these interactions starts with the oscillatory effect of the repeated electromagnetic stimulation (REMFS). These oscillations affect the interfacial water of an RNA causing changes at the quantum and molecular levels that release protons by quantum tunneling. Then protonation of RNA produces conformational changes that allow it to bind and activate Heat Shock Transcription Factor 1 (HSF1). Activated HSF1 binds to the DNA expressing chaperones that help regulate autophagy and degradation of abnormal proteins. This action helps to prevent and treat diseases such as Alzheimer's and Parkinson's disease (PD) by increasing clearance of pathologic proteins. This framework is based on multiple mathematical models, computer simulations, biophysical experiments, and cellular and animal studies. Results of the literature review and our research point towards the capacity of REMFS to manipulate various networks altered in aging (Reale et al. PloS one 9, e104973, 2014), including delay of cellular senescence (Perez et al. 2008, Exp Gerontol 43, 307-316) and reduction in levels of amyloid-β peptides (Aβ) (Perez et al. 2021, Sci Rep 11, 621). Results of these experiments using REMFS at low frequencies can be applied to the treatment of patients with age-related diseases. The use of EMF as a non-invasive therapeutic modality for Alzheimer's disease, specifically, holds promise. It is also necessary to consider the complicated and interconnected genetic and epigenetic effects of the REMFS-biological system's interaction while avoiding any possible adverse effects.Item Profiling of microglial-originated microvesicles to unearthing their lurking potential as potent foreseeable biomarkers for the diagnosis of Alzheimer’s disease: A systematic review(Wolters Kluwer, 2024-09-26) Kanuri, Sri Harsha; Sirrkay, Prapthi Jayesh; Neurology, School of MedicineBackground: Alzheimer's Disease is a neurodegenerative disease characterized by accumulation of phosphorylated tau and amyloid deposits within the brain tissues in the elderly population. Numerous studies established that amassment of these toxic accretions within the brain tissues initiates neuronal demise and synaptic impairment which becomes the underlying basis for memory loss and cognitive abnormalities in these patients. Hypothesis: Hypoxia, oxidative stress, and inflammation are commonly encountered perils in the neuronal milieu that derail the neuron-synapse interactions and maneuver them to undergo apoptosis. A spinoff from neuronal desecration is microglial activation which forms a cardinal role in mounting innate immune defenses for warding off and reversing off toxic stimulus encountered. Results: A potential ramification of microglial activation in this context is assembly, processing and exuding of micro-vesicles into the extracellular space. These micro-vesicles will be packaged with amyloid and tau deposits which accumulate intracellularly within microglial cells secondary to their professional scavenging function. These microglial MVs are prone to seed tau and amyloid beta into the surrounding neuron-synapse framework, thus are implicated in spreading the disease pathology in AD. Conclusions: Therefore, these MVs can be considered as an omen for disease initiation, progression, monitoring as well gauging the treatment response in the clinical AD cohorts. We speculate future research studies to unmask the dormant potential of these microglial MVs as reliable markers for diagnosis, evaluating the disease progression as well as treatment in AD. This will open the door for early diagnosis of AD so as to prioritize management and optimize clinical outcomes..Item The global Alzheimer's Association round robin study on plasma amyloid β methods(Wiley, 2021-10-14) Pannee, Josef; Shaw, Leslie M.; Korecka, Magdalena; Waligorska, Teresa; Teunissen, Charlotte E.; Stoops, Erik; Vanderstichele, Hugo M. J.; Mauroo, Kimberley; Verberk, Inge M. W.; Keshavan, Ashvini; Pesini, Pedro; Sarasa, Leticia; Pascual-Lucas, Maria; Fandos, Noelia; Allué, José-Antonio; Portelius, Erik; Andreasson, Ulf; Yoda, Ritsuko; Nakamura, Akinori; Kaneko, Naoki; Yang, Shieh-Yueh; Liu, Huei-Chun; Palme, Stefan; Bittner, Tobias; Mawuenyega, Kwasi G.; Ovod, Vitaliy; Bollinger, James; Bateman, Randall J.; Li, Yan; Dage, Jeffrey L.; Stomrud, Erik; Hansson, Oskar; Schott, Jonathan M.; Blennow, Kaj; Zetterberg, Henrik; Neurology, School of MedicineIntroduction: Blood-based assays to measure brain amyloid beta (Aβ) deposition are an attractive alternative to the cerebrospinal fluid (CSF)-based assays currently used in clinical settings. In this study, we examined different blood-based assays to measure Aβ and how they compare among centers and assays. Methods: Aliquots from 81 plasma samples were distributed to 10 participating centers. Seven immunological assays and four mass-spectrometric methods were used to measure plasma Aβ concentrations. Results: Correlations were weak for Aβ42 while Aβ40 correlations were stronger. The ratio Aβ42/Aβ40 did not improve the correlations and showed weak correlations. Discussion: The poor correlations for Aβ42 in plasma might have several potential explanations, such as the high levels of plasma proteins (compared to CSF), sensitivity to pre-analytical sample handling and specificity, and cross-reactivity of different antibodies. Different methods might also measure different pools of plasma Aβ42. We, however, hypothesize that greater correlations might be seen in future studies because many of the methods have been refined during completion of this study.