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Dekhtyar M, Foret JT, Simon S, Shumake J, Clark AL, Haley AP. An examination of the clinical utility of phonemic fluency in healthy adults and adults with mild cognitive impairment. APPLIED NEUROPSYCHOLOGY. ADULT 2024; 31:703-711. [PMID: 35438021 DOI: 10.1080/23279095.2022.2061860] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The Controlled Oral Word Association Test (COWAT) is a widely utilized measure of phonemic fluency. However, two issues remain: (1) whether demographic, cognitive variables, or version of test administered predict performance; (2) if the test is predictive of Mild Cognitive Impairment (MCI). Recent studies report that item-level analyses such as lexical frequency may be more sensitive to early cognitive change. The purpose of this study was to examine the clinical utility of the COWAT, considering both total correct words and the lexical frequency. Sixty-seven healthy adults and thirty-seven adults with MCI completed neuropsychological testing. Mann-Whitney U tests were used to determine if there was a difference in COWAT performance between groups. Elastic net regression models were used to assess whether variance in total scores/lexical frequencies can be predicted by demographics, test version, or diagnosis; which cognitive tests explained the variance in performance; and how total scores and lexical frequencies compared with other cognitive tests in predicting diagnosis. Overall, individuals with MCI produced fewer and higher frequency words. The variance in total correct words or lexical frequency was not explained by demographics, test version, or diagnosis. Total correct words was a more important predictor of diagnosis than lexical frequency.
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Affiliation(s)
- Maria Dekhtyar
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA
| | - Janelle T Foret
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA
| | - Sarah Simon
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA
| | - Jason Shumake
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA
| | - Alexandra L Clark
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA
| | - Andreana P Haley
- Department of Psychology, The University of Texas at Austin, Austin, TX, USA
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Goodman MJ, Li XR, Livschitz J, Huang CC, Bendlin BB, Granadillo ED. Comparing Symmetric Dimethylarginine and Amyloid-β42 as Predictors of Alzheimer's Disease Development. J Alzheimers Dis Rep 2023; 7:1427-1444. [PMID: 38225970 PMCID: PMC10789286 DOI: 10.3233/adr-230054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 11/15/2023] [Indexed: 01/17/2024] Open
Abstract
Background Physicians may soon be able to diagnose Alzheimer's disease (AD) in its early stages using fluid biomarkers like amyloid. However, it is acknowledged that additional biomarkers need to be characterized which would facilitate earlier monitoring of AD pathogenesis. Objective To determine if a potential novel inflammation biomarker for AD, symmetric dimethylarginine, has utility as a baseline serum biomarker for discriminating prodromal AD from cognitively unimpaired controls in comparison to cerebrospinal fluid amyloid-β42 (Aβ42). Methods Data including demographics, magnetic resonance imaging and fluorodeoxyglucose-positron emission tomography scans, Mini-Mental State Examination and Functional Activities Questionnaire scores, and biomarker concentrations were obtained from the Alzheimer's Disease Neuroimaging Initiative for a total of 146 prodromal AD participants and 108 cognitively unimpaired controls. Results Aβ42 (p = 0.65) and symmetric dimethylarginine (p = 0.45) were unable to predict age-matched cognitively unimpaired controls and prodromal AD participants. Aβ42 was negatively associated with regional brain atrophy and hypometabolism as well as cognitive and functional decline in cognitively unimpaired control participants (p < 0.05) that generally decreased in time. There were no significant associations between Aβ42 and symmetric dimethylarginine with imaging or neurocognitive biomarkers in prodromal AD patients. Conclusions Correlations were smaller between Aβ42 and neuropathological biomarkers over time and were absent in prodromal AD participants, suggesting a plateau effect dependent on age and disease stage. Evidence supporting symmetric dimethylarginine as a novel biomarker for AD as a single measurement was not found.
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Affiliation(s)
| | - Xin Ran Li
- Medical College of Wisconsin, Wauwatosa, WI, USA
| | | | | | | | - Elias D. Granadillo
- Medical College of Wisconsin, Wauwatosa, WI, USA
- University of Wisconsin, Madison, WI, USA
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3
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Maidman A, Wang L, Zhou XH, Sherwood B. Quantile partially linear additive model for data with dropouts and an application to modeling cognitive decline. Stat Med 2023; 42:2729-2745. [PMID: 37075804 DOI: 10.1002/sim.9745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 03/24/2023] [Accepted: 04/02/2023] [Indexed: 04/21/2023]
Abstract
The National Alzheimer's Coordinating Center Uniform Data Set includes test results from a battery of cognitive exams. Motivated by the need to model the cognitive ability of low-performing patients we create a composite score from ten tests and propose to model this score using a partially linear quantile regression model for longitudinal studies with non-ignorable dropouts. Quantile regression allows for modeling non-central tendencies. The partially linear model accommodates nonlinear relationships between some of the covariates and cognitive ability. The data set includes patients that leave the study prior to the conclusion. Ignoring such dropouts will result in biased estimates if the probability of dropout depends on the response. To handle this challenge, we propose a weighted quantile regression estimator where the weights are inversely proportional to the estimated probability a subject remains in the study. We prove that this weighted estimator is a consistent and efficient estimator of both linear and nonlinear effects.
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Affiliation(s)
- Adam Maidman
- School of Statistics, University of Minnesota, Minneapolis, Minnesota
| | - Lan Wang
- Miami Herbert Business School, University of Miami, Coral Gables, Florida
| | - Xiao-Hua Zhou
- Department of Biostatistics and Beijing International Center for Mathematical Research, Peking University, Beijing, China
| | - Ben Sherwood
- School of Business, University of Kansas, Lawrence, Kansas
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Bhargavan B, Woollard SM, McMillan JE, Kanmogne GD. CCR5 antagonist reduces HIV-induced amyloidogenesis, tau pathology, neurodegeneration, and blood-brain barrier alterations in HIV-infected hu-PBL-NSG mice. Mol Neurodegener 2021; 16:78. [PMID: 34809709 PMCID: PMC8607567 DOI: 10.1186/s13024-021-00500-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 11/03/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Neurocognitive impairment is present in 50% of HIV-infected individuals and is often associated with Alzheimer's Disease (AD)-like brain pathologies, including increased amyloid-beta (Aβ) and Tau hyperphosphorylation. Here, we aimed to determine whether HIV-1 infection causes AD-like pathologies in an HIV/AIDS humanized mouse model, and whether the CCR5 antagonist maraviroc alters HIV-induced pathologies. METHODS NOD/scid-IL-2Rγcnull mice engrafted with human blood leukocytes were infected with HIV-1, left untreated or treated with maraviroc (120 mg/kg twice/day). Human cells in animal's blood were quantified weekly by flow cytometry. Animals were sacrificed at week-3 post-infection; blood and tissues viral loads were quantified using p24 antigen ELISA, RNAscope, and qPCR. Human (HLA-DR+) cells, Aβ-42, phospho-Tau, neuronal markers (MAP 2, NeuN, neurofilament-L), gamma-secretase activating protein (GSAP), and blood-brain barrier (BBB) tight junction (TJ) proteins expression and transcription were quantified in brain tissues by immunohistochemistry, immunofluorescence, immunoblotting, and qPCR. Plasma Aβ-42, Aβ-42 cellular uptake, release and transendothelial transport were quantified by ELISA. RESULTS HIV-1 significantly decreased human (h)CD4+ T-cells and hCD4/hCD8 ratios; decreased the expression of BBB TJ proteins claudin-5, ZO-1, ZO-2; and increased HLA-DR+ cells in brain tissues. Significantly, HIV-infected animals showed increased plasma and brain Aβ-42 and phospho-Tau (threonine181, threonine231, serine396, serine199), associated with transcriptional upregulation of GSAP, an enzyme that catalyzes Aβ formation, and loss of MAP 2, NeuN, and neurofilament-L. Maraviroc treatment significantly reduced blood and brain viral loads, prevented HIV-induced loss of neuronal markers and TJ proteins; decreased HLA-DR+ cells infiltration in brain tissues, significantly reduced HIV-induced increase in Aβ-42, GSAP, and phospho-Tau. Maraviroc also reduced Aβ retention and increased Aβ release in human macrophages; decreased the receptor for advanced glycation end products (RAGE) and increased low-density lipoprotein receptor-related protein-1 (LRP1) expression in human brain endothelial cells. Maraviroc induced Aβ transendothelial transport, which was blocked by LRP1 antagonist but not RAGE antagonist. CONCLUSIONS Maraviroc significantly reduced HIV-induced amyloidogenesis, GSAP, phospho-Tau, neurodegeneration, BBB alterations, and leukocytes infiltration into the CNS. Maraviroc increased cellular Aβ efflux and transendothelial Aβ transport via LRP1 pathways. Thus, therapeutically targeting CCR5 could reduce viremia, preserve the BBB and neurons, increased brain Aβ efflux, and reduce AD-like neuropathologies.
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Affiliation(s)
- Biju Bhargavan
- Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198-5800 USA
| | - Shawna M. Woollard
- Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198-5800 USA
- Huvepharma, 421 W Industrial Lake Drive, Lincoln, NE 68528 USA
| | - Jo Ellyn McMillan
- Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198-5800 USA
| | - Georgette D. Kanmogne
- Department of Pharmacology and Experimental Neuroscience, College of Medicine, University of Nebraska Medical Center, 985800 Nebraska Medical Center, Omaha, NE 68198-5800 USA
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5
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Liu Y, Zhang S, He B, Chen L, Ke D, Zhao S, Zhang Y, Wei W, Xu Z, Xu Z, Yin Y, Mo W, Li Y, Gao Y, Li S, Wang W, Yu H, Wu D, Pi G, Jiang T, Deng M, Xiong R, Lei H, Tian N, He T, Sun F, Zhou Q, Wang X, Ye J, Li M, Hu N, Song G, Peng W, Zheng C, Zhang H, Wang JZ. Periphery Biomarkers for Objective Diagnosis of Cognitive Decline in Type 2 Diabetes Patients. Front Cell Dev Biol 2021; 9:752753. [PMID: 34746146 PMCID: PMC8564071 DOI: 10.3389/fcell.2021.752753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/23/2021] [Indexed: 12/03/2022] Open
Abstract
Introduction: Type 2 diabetes mellitus (T2DM) is an independent risk factor of Alzheimer’s disease (AD), and populations with mild cognitive impairment (MCI) have high incidence to suffer from AD. Therefore, discerning who may be more vulnerable to MCI, among the increasing T2DM populations, is important for early intervention and eventually decreasing the prevalence rate of AD. This study was to explore whether the change of plasma β-amyloid (Aβ) could be a biomarker to distinguish MCI (T2DM-MCI) from non-MCI (T2DM-nMCI) in T2DM patients. Methods: Eight hundred fifty-two T2DM patients collected from five medical centers were assigned randomly to training and validation cohorts. Plasma Aβ, platelet glycogen synthase kinase-3β (GSK-3β), apolipoprotein E (ApoE) genotypes, and olfactory and cognitive functions were measured by ELISA, dot blot, RT-PCR, Connecticut Chemosensory Clinical Research Center (CCCRC) olfactory test based on the diluted butanol, and Minimum Mental State Examination (MMSE) test, respectively, and multivariate logistic regression analyses were applied. Results: Elevation of plasma Aβ1-42/Aβ1-40 is an independent risk factor of MCI in T2DM patients. Although using Aβ1-42/Aβ1-40 alone only reached an AUC of 0.631 for MCI diagnosis, addition of the elevated Aβ1-42/Aβ1-40 to our previous model (i.e., activated platelet GSK-3β, ApoE ε4 genotype, olfactory decline, and aging) significantly increased the discriminating efficiency of T2DM-MCI from T2DM-nMCI, with an AUC of 0.846 (95% CI: 0.794–0.897) to 0.869 (95% CI: 0.822–0.916) in the training cohort and an AUC of 0.848 (95% CI: 0.815–0.882) to 0.867 (95% CI: 0.835–0.899) in the validation cohort, respectively. Conclusion: A combination of the elevated plasma Aβ1-42/Aβ1-40 with activated platelet GSK-3β, ApoE ε4 genotype, olfactory decline, and aging could efficiently diagnose MCI in T2DM patients. Further longitudinal studies may consummate the model for early prediction of AD.
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Affiliation(s)
- Yanchao Liu
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Department of Neurosurgery, Tongji Medical College, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Shujuan Zhang
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Benrong He
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Liangkai Chen
- Department of Nutrition and Food Hygiene, Hubei Key Laboratory of Food Nutrition and Safety, Ministry of Education Key Laboratory of Environment and Health, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dan Ke
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shi Zhao
- Department of Endocrinology, Central Hospital of Wuhan, Wuhan, China
| | - Yao Zhang
- Liyuan Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wei Wei
- Department of Endocrinology, Central Hospital of Wuhan, Wuhan, China
| | - Zhipeng Xu
- Department of Neurology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zihui Xu
- Department of Endocrinology, Central Hospital of Wuhan, Wuhan, China
| | - Ying Yin
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wen Mo
- Health Service Center of Jianghan District, Wuhan, China
| | - Yanni Li
- Health Service Center of Jianghan District, Wuhan, China
| | - Yang Gao
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shihong Li
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Weijin Wang
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiling Yu
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dongqin Wu
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guilin Pi
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Tao Jiang
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mingmin Deng
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Rui Xiong
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Huiyang Lei
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Na Tian
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ting He
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Fei Sun
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qiuzhi Zhou
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Wang
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Jinwang Ye
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Mengzhu Li
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Nan Hu
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Guoda Song
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Wenju Peng
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Chenghong Zheng
- Department of Endocrinology, Wuhan Hospital of Traditional Chinese Medicine, Wuhan, China
| | - Huaqiu Zhang
- Department of Neurosurgery, Tongji Medical College, Tongji Hospital, Huazhong University of Science and Technology, Wuhan, China
| | - Jian-Zhi Wang
- Ministry of Education Key Laboratory for Neurological Disorders, Hubei Key Laboratory for Neurological Disorders, Department of Pathophysiology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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Chen TB, Lin KJ, Lin SY, Lee YJ, Lin YC, Wang CY, Chen JP, Wang PN. Prediction of Cerebral Amyloid Pathology Based on Plasma Amyloid and Tau Related Markers. Front Neurol 2021; 12:619388. [PMID: 34671305 PMCID: PMC8520900 DOI: 10.3389/fneur.2021.619388] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 09/07/2021] [Indexed: 11/26/2022] Open
Abstract
Background and Purpose: Pyroglutamate-modified β-amyloid peptide (AβpE) is crucial for AD pathophysiological process. The potential associations of plasma AβpE and total tau (t-tau) with brain Aβ burden and cognitive performance remain to be clarified. Methods: Forty-six subjects with unimpaired cognition, mild cognitive impairment, or very mild dementia were enrolled. Plasma levels of AβpE3−40, t-tau, and Aβ42 were quantified by immunomagnetic reduction (IMR) assays. We analyzed individual and combined biomarker correlations with neuropsychological scores and Aβ positivity determined by 18F-florbetapir positron emission tomography (PET). Results: Both plasma AβpE3−40 levels and AβpE3−40/t-tau ratios correlated negatively with short-term memory and global cognition scores, while correlating positively with PET standardized uptake value ratios (SUVRs). Among the biomarkers analyzed, the combination of AβpE3−40 in a ratio with t-tau had the best discriminatory ability for Aβ PET positivity. Likewise, logistic regression analysis showed that AβpE3−40/t-tau was a highly robust predictor of Aβ PET positivity after controlling for relevant demographic covariates. Conclusion: Plasma AβpE3−40/t-tau ratios correlate with cognitive function and cerebral Aβ burden. The suitability of AβpE3−40/t-tau as a candidate clinical biomarker of AD pathology in the brain should be examined further in larger studies.
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Affiliation(s)
- Ting-Bin Chen
- Department of Neurology, Neurological Institute, Taichung Veterans General Hospital, Taichung, Taiwan.,Dementia Center, Taichung Veterans General Hospital, Taichung, Taiwan.,Center for Geriatrics and Gerontology, Taichung Veterans General Hospital, Taichung, Taiwan
| | - Kun-Ju Lin
- Department of Nuclear Medicine and Molecular Imaging Center, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan.,Healthy Aging Research Center and Department of Medical Imaging and Radiological Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Szu-Ying Lin
- Taipei Municipal Gan-Dau Hospital, Taipei, Taiwan
| | - Yi-Jung Lee
- Division of Neurology, Department of Medicine, Taipei City Hospital Renai Branch, Taipei, Taiwan
| | - Yi-Cheng Lin
- Taipei Municipal Gan-Dau Hospital, Taipei, Taiwan.,School of Life Sciences, Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan
| | - Chen-Yu Wang
- Division of General Neurology, Department of Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan
| | - Jun-Peng Chen
- Biostatistics Task Force of Taichung Veterans General Hospital, Taichung, Taiwan
| | - Pei-Ning Wang
- Division of General Neurology, Department of Neurological Institute, Taipei Veterans General Hospital, Taipei, Taiwan.,Faculty of Medicine, School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan.,Brain Research Center, National Yang Ming Chiao Tung University, Taipei, Taiwan
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7
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Li D, Zhang L, Nelson NW, Mielke MM, Yu F. Plasma Neurofilament Light and Future Declines in Cognition and Function in Alzheimer's Disease in the FIT-AD Trial. J Alzheimers Dis Rep 2021; 5:601-611. [PMID: 34514342 PMCID: PMC8385429 DOI: 10.3233/adr-210302] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/09/2021] [Indexed: 01/27/2023] Open
Abstract
Background: Utilities of blood-based biomarkers in Alzheimer’s disease (AD) clinical trials remain unknown. Objective: To evaluate the ability of plasma neurofilament light chain (NfL) to predict future declines in cognition and activities of daily living (ADL) outcomes in 26 older adults with mild-to-moderate AD dementia from the FIT-AD Trial. Methods: Plasma NfL was measured at baseline and 3 and 6 months. Cognition and ADL were assessed using the AD Assessment Scale-Cognition (ADAS-Cog) and AD Uniform Dataset Instruments and Disability Assessment for Dementia (DAD), respectively, at baseline, 3, 6, 9, and 12 months. Linear mixed effects models were used to examine the associations between baseline or change in plasma NfL and changes in outcomes. Results: Higher baseline plasma NfL was associated with greater rate of decline in ADAS-Cog from baseline to 6 months (standardized estimate of 0.00462, p = 0.02853) and in ADL from baseline to 12 months (standardized estimate of –0.00284, p = 0.03338). Greater increase in plasma NfL in short term from baseline to 3 months was associated with greater rate of decline in memory and ADL from 3 to 6 months (standardized estimate of –0.04638 [0.003], p = 0.01635; standardized estimate of –0.03818, p = 0.0435) and greater rate of decline in ADL from 3 to 12 month (standardized estimate of –0.01492, p = 0.01082). Conclusion: This study demonstrated that plasma NfL might have the potential to predict cognitive and function decline up to 12 months. However, future studies with bigger sample sizes need to confirm the findings.
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Affiliation(s)
- Danni Li
- Department of Lab Medicine and Pathology, University of Minnesota, Minneapolis, MN, USA
| | - Lin Zhang
- School of Public Health, Division of Biostatistics, University of Minnesota, Minneapolis, MN, USA
| | - Nathaniel W Nelson
- Graduate School of Professional Psychology, University of St. Thomas, Minnesota, St. Paul, MN, USA
| | - Michelle M Mielke
- Departments of Health Sciences Research and Neurology, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Fang Yu
- Edson College of Nursing and Health Innovation, Arizona State University, Phoenix, AZ, USA
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8
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He L, de Souto Barreto P, Giudici KV, Aggarwal G, Nguyen AD, Morley JE, Li Y, Bateman RJ, Vellas B. Cross-Sectional and Longitudinal Associations Between Plasma Neurodegenerative Biomarkers and Physical Performance Among Community-Dwelling Older Adults. J Gerontol A Biol Sci Med Sci 2021; 76:1874-1881. [PMID: 33186456 DOI: 10.1093/gerona/glaa284] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Plasma amyloid-beta (Aβ), neurofilament light chain (NfL), and progranulin (PGRN) have been related to multiple neurodegenerative conditions that might affect physical performance. The aim of this study was to explore the relationship between these plasma neurodegenerative markers and physical performance among community-dwelling older adults. METHODS Five hundred and seven older adults (aged 76 ± 5 years) previously recruited in the Multidomain Alzheimer's Preventive Trial, and had received blood and physical performance tests, were included in this study. Plasma Aβ (Aβ 42/Aβ 40 ratio), NfL, and PGRN levels were measured. Physical performance was assessed by handgrip strength and the Short Physical Performance Battery (combining gait speed, chair stands, and balance tests). Physical performance measured at the same time point and after the blood tests were used. Mixed-effect linear models were performed with age, sex, allocation to Multidomain Alzheimer's Preventive Trial group, body mass index, and Mini-Mental State Examination score as covariates. RESULTS The mean values of Aβ 42/Aβ 40 ratio, NfL, and PGRN were 0.11, 84.06 pg/mL, and 45.43 ng/mL, respectively. At the cross-sectional level, higher plasma NfL was associated with a lower Short Physical Performance Battery score (β = -0.004, 95% CI [-0.007, -0.001]). At the longitudinal level, higher PGRN levels were associated with decreasing handgrip strength over time (β = -0.02, 95% CI [-0.04, -0.007]). All the other associations were statistically nonsignificant. CONCLUSION Our findings suggest the possibility of using plasma NfL and PGRN as markers of physical performance in older adults.
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Affiliation(s)
- Lingxiao He
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, France
| | - Philipe de Souto Barreto
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, France.,UPS/Inserm UMR1027, University of Toulouse III, Toulouse, France
| | - Kelly V Giudici
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, France
| | - Geetika Aggarwal
- Division of Geriatric Medicine, Saint Louis University School of Medicine, Missouri.,Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, Missouri
| | - Andrew D Nguyen
- Division of Geriatric Medicine, Saint Louis University School of Medicine, Missouri.,Henry and Amelia Nasrallah Center for Neuroscience, Saint Louis University, Missouri
| | - John E Morley
- Division of Geriatric Medicine, Saint Louis University School of Medicine, Missouri
| | - Yan Li
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Randall J Bateman
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri
| | - Bruno Vellas
- Gérontopôle de Toulouse, Institut du Vieillissement, Centre Hospitalo-Universitaire de Toulouse, France.,UPS/Inserm UMR1027, University of Toulouse III, Toulouse, France
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9
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Dominguez J, de Guzman MF, Chen SHA, Sano M, Waldemar G, Phung TKT. Filipino Multicomponent Intervention to Maintain Cognitive Performance in High-Risk Population (FINOMAIN): Study Protocol for a Cluster Randomized Controlled Trial. Front Neurol 2021; 12:685721. [PMID: 34557142 PMCID: PMC8453078 DOI: 10.3389/fneur.2021.685721] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Accepted: 07/20/2021] [Indexed: 12/03/2022] Open
Abstract
Background: More than half of the people with dementia live in lower-middle income countries (LMIC), yet we lack research and evidence-based knowledge to guide health promotion and prevention strategies for cognitive decline. In the Philippines, the prevalence of mild cognitive impairment (MCI) and cardiovascular risk factors among older persons are high, making this population at high risk for developing dementia. This protocol describes a cluster randomized controlled trial that aims to investigate the efficacy of a multicomponent intervention to maintain cognitive performance among high-risk population. Methods: This is a cluster-randomized, two-arm, single-blind trial of a multicomponent intervention that combines dance called INDAK (Improving Neurocognition through Dance and Kinesthetics), nutrition counseling, and vascular risk management. The intervention arm will receive 12 months (1-h, twice per week) of INDAK and every 3 months of nutrition counseling and intensive vascular risk management and monitoring. The control group will receive the usual vascular care advice and referral. A total of 605 (20-25 clusters per arm) community-dwelling Filipino older adults aged ≥ 60 years old with MCI will participate in the study and will be assessed at baseline, 6th- and 12th-month follow-up. The primary outcome is cognitive performance assessed by the Alzheimer's Disease Assessment Scale-Cognitive (ADAS-Cog), Mnemonic Similarity Tasks (MST), and executive function composite (EFC). Secondary outcomes are functional connectivity assessed through brain imaging, and measures of behavioral, functional level, and quality of life. Discussion: The study aims to provide scientific evidence on a public health intervention that is contextualized in a community setting to reduce dementia risk among older adults with MCI. This model can be an ecological, low-cost, and effective program, thereby conducive to widespread implementation in the Philippines as well as in other low-resource settings with similar public health challenges. The pilot phase was underway with eight villages (clusters), but temporarily interrupted by the pandemic. The full study is anticipated to start after community restrictions are eased.
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Affiliation(s)
- Jacqueline Dominguez
- St. Luke's Medical Center, Institute for Neurosciences, Quezon City, Philippines
- Institute for Dementia Care Asia, Quezon City, Philippines
| | | | - S. H. Annabel Chen
- Center of Research and Development in Learning, Psychology, School of Social Sciences, Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore
| | - Mary Sano
- Department of Psychiatry, Mt. Sinai Alzheimer's Disease Research Center, Icahn School of Medicine, New York, NY, United States
| | - Gunhild Waldemar
- Danish Dementia Research Center, Rigohospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thien Kieu Thi Phung
- Danish Dementia Research Center, Rigohospitalet, University of Copenhagen, Copenhagen, Denmark
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10
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Gene Expression Profile in Different Age Groups and Its Association with Cognitive Function in Healthy Malay Adults in Malaysia. Cells 2021; 10:cells10071611. [PMID: 34199148 PMCID: PMC8304476 DOI: 10.3390/cells10071611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/13/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
The mechanism of cognitive aging at the molecular level is complex and not well understood. Growing evidence suggests that cognitive differences might also be caused by ethnicity. Thus, this study aims to determine the gene expression changes associated with age-related cognitive decline among Malay adults in Malaysia. A cross-sectional study was conducted on 160 healthy Malay subjects, aged between 28 and 79, and recruited around Selangor and Klang Valley, Malaysia. Gene expression analysis was performed using a HumanHT-12v4.0 Expression BeadChip microarray kit. The top 20 differentially expressed genes at p < 0.05 and fold change (FC) = 1.2 showed that PAFAH1B3, HIST1H1E, KCNA3, TM7SF2, RGS1, and TGFBRAP1 were regulated with increased age. The gene set analysis suggests that the Malay adult's susceptibility to developing age-related cognitive decline might be due to the changes in gene expression patterns associated with inflammation, signal transduction, and metabolic pathway in the genetic network. It may, perhaps, have important implications for finding a biomarker for cognitive decline and offer molecular targets to achieve successful aging, mainly in the Malay population in Malaysia.
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11
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Castillo-Mendieta T, Arana-Lechuga Y, Campos-Peña V, Sosa AL, Orozco-Suarez S, Pinto-Almazán R, Segura-Uribe J, Javier Rodríguez-Sánchez de Tagle A, Ruiz-Sánchez E, Guerra-Araiza C. Plasma Levels of Amyloid-β Peptides and Tau Protein in Mexican Patients with Alzheimer's Disease. J Alzheimers Dis 2021; 82:S271-S281. [PMID: 34151786 DOI: 10.3233/jad-200912] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) causes memory deficit and alterations in other cognitive functions, mainly in adults over 60 years of age. As the diagnosis confirmation is performed by a postmortem neuropathological examination of the brain, this disease can be confused with other types of dementia at early stages. About 860,000 Mexicans are affected by dementia, most of them with insufficient access to adequate comprehensive health care services. Plasma biomarkers could be a rapid option for early diagnosis of the disease. OBJECTIVE This study aimed to analyze some plasma biomarkers (amyloid-β, tau, and lipids) in Mexican AD patients and control subjects with no associated neurodegenerative diseases. METHODS Plasma amyloid-β peptides (Aβ40 and Aβ42), total and phosphorylated tau protein (T-tau and P-tau), and cholesterol and triglyceride levels were quantified by enzyme-linked immunosorbent assay in AD patients and control subjects. RESULTS In Mexican AD patients, we found significantly lower levels of Aβ42 (p < 0.05) compared to the control group. In contrast, significantly higher levels of P-tau (p < 0.05) and triglycerides (p < 0.05) were observed in AD patients compared to controls. Furthermore, a significant correlation was found between the severity of dementia and plasma P-tau levels, Aβ42/Aβ40 and P-tau/T-tau ratios, and triglycerides concentrations. This correlation increased gradually with cognitive decline. CONCLUSION The detection of these plasma biomarkers is an initial step in searching for a timely, less invasive, and cost-efficient diagnosis in Mexicans.
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Affiliation(s)
- Tzayaka Castillo-Mendieta
- Unidad de Investigación Médica en Farmacología, Hospital de Especialidades Bernardo Sepúlveda, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.,Doctorado en Ciencias Biológicas y de la Salud, Universidad Autónoma Metropolitana, Mexico City, Mexico
| | - Yoaly Arana-Lechuga
- Sleep Disorders Clinic, Universidad Autónoma Metropolitana-Iztapalapa, Mexico City, Mexico
| | - Victoria Campos-Peña
- Laboratorio Experimental de Enfermedades Neurodegenerativas, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Mexico City, Mexico
| | - Ana Luisa Sosa
- Clínica de Demencia, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Mexico City, Mexico
| | - Sandra Orozco-Suarez
- Unidad de Investigación Médica en Enfermedades Neurológicas, Hospital de Especialidades Bernardo Sepúlveda, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
| | - Rodolfo Pinto-Almazán
- Laboratorio de Biología Molecular en Enfermedades Metabólicas y Neurodegenerativas, Unidad de Investigación, Hospital Regional de Alta Especialidad de Ixtapaluca, Ixtapaluca, State of Mexico, Mexico
| | - Julia Segura-Uribe
- Subdirección de Gestión de la Investigación, Hospital Infantil de México Federico Gómez, Secretaría de Salud, Mexico City, Mexico
| | - Aldo Javier Rodríguez-Sánchez de Tagle
- Unidad de Investigación Médica en Farmacología, Hospital de Especialidades Bernardo Sepúlveda, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico.,Coordinación de QFBT, Universidad del Valle de México-Chapultepec, México City, México
| | - Elizabeth Ruiz-Sánchez
- Laboratorio de Neurotoxicología, Instituto Nacional de Neurología y Neurocirugía Manuel Velasco Suárez, Mexico City, Mexico
| | - Christian Guerra-Araiza
- Unidad de Investigación Médica en Farmacología, Hospital de Especialidades Bernardo Sepúlveda, Centro Médico Nacional Siglo XXI, Instituto Mexicano del Seguro Social, Mexico City, Mexico
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12
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Feinkohl I, Schipke CG, Kruppa J, Menne F, Winterer G, Pischon T, Peters O. Plasma Amyloid Concentration in Alzheimer's Disease: Performance of a High-Throughput Amyloid Assay in Distinguishing Alzheimer's Disease Cases from Controls. J Alzheimers Dis 2021; 74:1285-1294. [PMID: 32176645 PMCID: PMC7242850 DOI: 10.3233/jad-200046] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Background: Collection of cerebrospinal fluid (CSF) for measurement of amyloid-β (Aβ) species is a gold standard in Alzheimer’s disease (AD) diagnosis, but has risks. Thus, establishing a low-risk blood Aβ test with high AD sensitivity and specificity is of outmost interest. Objective: We evaluated the ability of a commercially available plasma Aβ assay to distinguish AD patients from biomarker-healthy controls. Method: In a case-control design, we examined plasma samples from 44 AD patients (A + N+) and 49 controls (A–N–) from a memory clinic. AD was diagnosed using a combination of neuropsychological examination, CSF biomarker analysis and brain imaging. Total Aβ40 and total Aβ42 in plasma were measured through enzyme-linked immunosorbent assay (ELISA) technology using ABtest40 and ABtest42 test kits (Araclon Biotech Ltd.). Receiver operating characteristic (ROC) analyses with outcome AD were performed, and sensitivity and specificity were calculated. Results: Plasma Aβ42/40 was weakly positively correlated with CSF Aβ42/40 (Spearman’s rho 0.22; p = 0.037). Plasma Aβ42/40 alone was not able to statistically significantly distinguish between AD patients and controls (AUC 0.58; 95% CI 0.46, 0.70). At a cut-point of 0.076 maximizing sensitivity and specificity, plasma Aβ42/40 had a sensitivity of 61.2% and a specificity of 63.6%. Conclusion: In this sample, the high-throughput blood Aβ assay was not able to distinguish well between AD patients and controls. Whether or not the assay may be useful in large-scale epidemiological settings remains to be seen.
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Affiliation(s)
- Insa Feinkohl
- Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany
| | - Carola G Schipke
- Berlin Institute of Health (BIH), Berlin, Germany.,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health (BIH), Experimental & Clinical Research Center (ECRC), Berlin, Germany
| | - Jochen Kruppa
- Berlin Institute of Health (BIH), Berlin, Germany.,Institut für Biometrie und Klinische Epidemiologie, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health (BIH), Berlin, Germany
| | - Felix Menne
- Berlin Institute of Health (BIH), Berlin, Germany.,Department of Psychiatry and Psychotherapy, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health (BIH), Berlin, Germany
| | - Georg Winterer
- Berlin Institute of Health (BIH), Berlin, Germany.,Pharmaimage Biomarker Solutions GmbH, Berlin, Germany.,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health (BIH), Berlin, Germany
| | - Tobias Pischon
- Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association (MDC), Berlin, Germany.,Berlin Institute of Health (BIH), Berlin, Germany.,Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health (BIH), Berlin, Germany.,MDC/BIH Biobank, Max-Delbrueck-Center for Molecular Medicine in the Helmholtz Association (MDC), and Berlin Institute of Health (BIH), Berlin, Germany
| | - Oliver Peters
- Berlin Institute of Health (BIH), Berlin, Germany.,Department of Psychiatry and Psychotherapy, Campus Benjamin Franklin, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin and Berlin Institute of Health (BIH), Berlin, Germany
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13
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Yu F, Vock DM, Zhang L, Salisbury D, Nelson NW, Chow LS, Smith G, Barclay TR, Dysken M, Wyman JF. Cognitive Effects of Aerobic Exercise in Alzheimer's Disease: A Pilot Randomized Controlled Trial. J Alzheimers Dis 2021; 80:233-244. [PMID: 33523004 PMCID: PMC8075384 DOI: 10.3233/jad-201100] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2020] [Indexed: 12/20/2022]
Abstract
BACKGROUND Aerobic exercise has shown inconsistent cognitive effects in older adults with Alzheimer's disease (AD) dementia. OBJECTIVE To examine the immediate and longitudinal effects of 6-month cycling on cognition in older adults with AD dementia. METHODS This randomized controlled trial randomized 96 participants (64 to cycling and 32 to stretching for six months) and followed them for another six months. The intervention was supervised, moderate-intensity cycling for 20-50 minutes, 3 times a week for six months. The control was light-intensity stretching. Cognition was assessed at baseline, 3, 6, 9, and 12 months using the AD Assessment Scale-Cognition (ADAS-Cog). Discrete cognitive domains were measured using the AD Uniform Data Set battery. RESULTS The participants were 77.4±6.8 years old with 15.6±2.9 years of education, and 55% were male. The 6-month change in ADAS-Cog was 1.0±4.6 (cycling) and 0.1±4.1 (stretching), which were both significantly less than the natural 3.2±6.3-point increase observed naturally with disease progression. The 12-month change was 2.4±5.2 (cycling) and 2.2±5.7 (control). ADAS-Cog did not differ between groups at 6 (p = 0.386) and 12 months (p = 0.856). There were no differences in the 12-month rate of change in ADAS-Cog (0.192 versus 0.197, p = 0.967), memory (-0.012 versus -0.019, p = 0.373), executive function (-0.020 versus -0.012, p = 0.383), attention (-0.035 versus -0.033, p = 0.908), or language (-0.028 versus -0.026, p = 0.756). CONCLUSION Exercise may reduce decline in global cognition in older adults with mild-to-moderate AD dementia. Aerobic exercise did not show superior cognitive effects to stretching in our pilot trial, possibly due to the lack of power.
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Affiliation(s)
- Fang Yu
- University of Minnesota Division of Biostatistics, Minneapolis, MN, USA
| | - David M. Vock
- University of Minnesota Division of Biostatistics, Minneapolis, MN, USA
| | - Lin Zhang
- University of Minnesota Division of Biostatistics, Minneapolis, MN, USA
| | | | | | - Lisa S. Chow
- University of Minnesota School of Medicine, Minneapolis, MN, USA
| | - Glenn Smith
- University of Florida Department of Clinical and Health Psychology, Gainesville, FL, USA
| | | | - Maurice Dysken
- University of Minnesota School of Medicine, Minneapolis, MN, USA
| | - Jean F. Wyman
- University of Minnesota School of Nursing, Minneapolis, MN, USA
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14
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Giudici KV, de Souto Barreto P, Guyonnet S, Li Y, Bateman RJ, Vellas B. Assessment of Plasma Amyloid-β42/40 and Cognitive Decline Among Community-Dwelling Older Adults. JAMA Netw Open 2020; 3:e2028634. [PMID: 33331917 PMCID: PMC7747018 DOI: 10.1001/jamanetworkopen.2020.28634] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
IMPORTANCE Plasma measurement of amyloid-β (Aβ) peptides has been associated with cognitive function, but evidence of its ability to identify cognitive decline is still scarce. OBJECTIVE To investigate the associations between plasma Aβ42/40 and cognitive decline over time among community-dwelling older adults with subjective memory concerns. DESIGN, SETTING, AND PARTICIPANTS This multicenter cohort study used data from volunteers in the 5-year study Multidomain Alzheimer Preventive Trial (MAPT). Participants were aged 70 years or older and observed for a median (interquartile range) of 3.9 (2.0-4.0) years. Recruitment of participants started in May 2008 and ended in February 2011. Follow-up ended in April 2016. Data analysis was conducted from April to October 2020. EXPOSURE Plasma Aβ42 and Aβ40 were measured at 12 months for 448 participants (92.8%) and at 24 months for the rest. The moment of Aβ assessment was defined as the baseline for this study. MAIN OUTCOMES AND MEASURES Cognitive function was assessed at 12, 24, 36, 48, and 60 months by a composite cognitive score based on 4 tests; Mini Mental State Examination (MMSE); Clinical Dementia Rating, sum of boxes; and Alzheimer Disease Cooperative Study-Activities of Daily Living. Mixed-effect linear regressions were performed. RESULTS A total of 483 participants (median [IQR] age, 76.0 [73.0-80.0]; 286 [59.2%] women) were analyzed. Of them, 161 (33.3%) were classified as low plasma Aβ42/40 (≤0.107). After adjusting for age, sex, education, body mass index, Geriatric Depression Scale score, apolipoprotein E ε4 genotype, and MAPT intervention groups, low plasma Aβ42/40 was associated with more pronounced decline in composite cognitive score (adjusted between-group mean difference: -0.20, 95% CI, -0.34 to -0.07; P = .004) and decline in MMSE score (adjusted between-group mean difference: -0.59; 95% CI, -1.07 to -0.11; P = .02) during the follow-up period compared with the group with an Aβ42/40 ratio greater than 0.107. CONCLUSIONS AND RELEVANCE In this study, low plasma Aβ42/40 was associated with more pronounced decline in cognitive function (measured by multiple outcomes) over time. Findings suggest that plasma Aβ42/40 may be used to identify people at risk of cognitive decline, being an alternative to more complex and expensive measures, such as positron emission tomography imaging or cerebrospinal fluid measurement.
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Affiliation(s)
| | - Philipe de Souto Barreto
- Gerontopole of Toulouse, Institute of Ageing, Toulouse University Hospital, Toulouse, France
- UPS/Inserm UMR1027, University of Toulouse III, Toulouse, France
| | - Sophie Guyonnet
- Gerontopole of Toulouse, Institute of Ageing, Toulouse University Hospital, Toulouse, France
- UPS/Inserm UMR1027, University of Toulouse III, Toulouse, France
| | - Yan Li
- Department of Neurology, Washington University School of Medicine in St Louis, St Louis, Missouri
- Division of Biostatistics, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Randall John Bateman
- Department of Neurology, Washington University School of Medicine in St Louis, St Louis, Missouri
| | - Bruno Vellas
- Gerontopole of Toulouse, Institute of Ageing, Toulouse University Hospital, Toulouse, France
- UPS/Inserm UMR1027, University of Toulouse III, Toulouse, France
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15
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Cantero JL, Atienza M, Ramos-Cejudo J, Fossati S, Wisniewski T, Osorio RS. Plasma tau predicts cerebral vulnerability in aging. Aging (Albany NY) 2020; 12:21004-21022. [PMID: 33147571 PMCID: PMC7695405 DOI: 10.18632/aging.104057] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/25/2020] [Indexed: 12/11/2022]
Abstract
Identifying cerebral vulnerability in late life may help prevent or slow the progression of aging-related chronic diseases. However, non-invasive biomarkers aimed at detecting subclinical cerebral changes in the elderly are lacking. Here, we have examined the potential of plasma total tau (t-tau) for identifying cerebral and cognitive deficits in normal elderly subjects. Patterns of cortical thickness and cortical glucose metabolism were used as outcomes of cerebral vulnerability. We found that increased plasma t-tau levels were associated with widespread reductions of cortical glucose uptake, thinning of the temporal lobe, and memory deficits. Importantly, tau-related reductions of glucose consumption in the orbitofrontal cortex emerged as a determining factor of the relationship between cortical thinning and memory loss. Together, these results support the view that plasma t-tau may serve to identify subclinical cerebral and cognitive deficits in normal aging, allowing detection of individuals at risk for developing aging-related neurodegenerative conditions.
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Affiliation(s)
- Jose L. Cantero
- Laboratory of Functional Neuroscience, Pablo de Olavide University, Seville, Spain
- CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
| | - Mercedes Atienza
- Laboratory of Functional Neuroscience, Pablo de Olavide University, Seville, Spain
- CIBERNED, Network Center for Biomedical Research in Neurodegenerative Diseases, Madrid, Spain
| | - Jaime Ramos-Cejudo
- Division of Brain Aging, Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
| | - Silvia Fossati
- Alzheimer's Center at Temple, Lewis Katz School of Medicine, Temple University, Philadelphia, PA 19140, USA
| | - Thomas Wisniewski
- Departments of Neurology, Pathology and Psychiatry, Center for Cognitive Neurology, New York University School of Medicine, New York, NY 10016, USA
| | - Ricardo S. Osorio
- Division of Brain Aging, Department of Psychiatry, New York University School of Medicine, New York, NY 10016, USA
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16
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Midlife Study of the Louisville Twins: Connecting Cognitive Development to Biological and Cognitive Aging. Behav Genet 2019; 50:73-83. [PMID: 31820295 DOI: 10.1007/s10519-019-09983-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 11/18/2019] [Indexed: 10/25/2022]
Abstract
The Louisville Twin Study (LTS) began in 1958 and became a premier longitudinal twin study of cognitive development. The LTS continuously collected data from twins through 2000 after which the study closed indefinitely due to lack of funding. Now that the majority of the sample is age 40 or older (61.36%, N = 1770), the LTS childhood data can be linked to midlife cognitive functioning, among other physical, biological, social, and psychiatric outcomes. We report results from two pilot studies in anticipation of beginning the midlife phase of the LTS. The first pilot study was a participant tracking study, in which we showed that approximately 90% of the Louisville families randomly sampled (N = 203) for the study could be found. The second pilot study consisted of 40 in-person interviews in which twins completed cognitive, memory, biometric, and functional ability measures. The main purpose of the second study was to correlate midlife measures of cognitive functioning to a measure of biological age, which is an alternative index to chronological age that quantifies age as a function of the breakdown of structural and functional physiological systems, and then to relate both of these measures to twins' cognitive developmental trajectories. Midlife IQ was uncorrelated with biological age (- .01) while better scores on episodic memory more strongly correlated with lower biological age (- .19 to - .31). As expected, midlife IQ positively correlated with IQ measures collected throughout childhood and adolescence. Additionally, positive linear rates of change in FSIQ scores in childhood significantly correlated with biological age (- .68), physical functioning (.71), and functional ability (- .55), suggesting that cognitive development predicts lower biological age, better physical functioning, and better functional ability. In sum, the Louisville twins can be relocated to investigate whether and how early and midlife cognitive and physical health factors contribute to cognitive aging.
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Plasma Aβ42 and Total Tau Predict Cognitive Decline in Amnestic Mild Cognitive Impairment. Sci Rep 2019; 9:13984. [PMID: 31562355 PMCID: PMC6764975 DOI: 10.1038/s41598-019-50315-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 09/04/2019] [Indexed: 01/21/2023] Open
Abstract
Levels of amyloid-β (Aβ) and tau peptides in brain have been associated with Alzheimer disease (AD). The current study investigated the abilities of plasma Aβ42 and total-tau (t-tau) levels in predicting cognitive decline in subjects with amnestic mild cognitive impairment (MCI). Plasma Aβ42 and t-tau levels were quantified in 22 participants with amnestic MCI through immunomagnetic reduction (IMR) assay at baseline. The cognitive performance of participants was measured through neuropsychological tests at baseline and annual follow-up (average follow-up period of 1.5 years). The predictive value of plasma Aβ42 and t-tau for cognitive status was evaluated. We found that higher levels of Aβ42 and t-tau are associated with lower episodic verbal memory performance at baseline and cognitive decline over the course of follow-up. While Aβ42 or t-tau alone had moderate-to-high discriminatory value in the identification of future cognitive decline, the product of Aβ42 and t-tau offered greater differential value. These preliminary results might suggest that high levels of plasma Aβ42 and t-tau in amnestic MCI are associated with later cognitive decline. A further replication with a larger sample over a longer time period to validate and determine their long-term predictive value is warranted.
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Abstract
UNLABELLED ABSTRACTObjectives:This study aimed to determine the diagnostic utility of a Chinese test battery for evaluating cognitive loss in elderly Chinese Americans. METHODS Data from a pilot study at the Mount Sinai Alzheimer's Disease Research Center was examined. All participants were > 65 years old, primarily Chinese speaking, with adequate sensorimotor capacity to complete cognitive tests. A research diagnosis of normal mild cognitive impairment (MCI) or Alzheimer's disease (AD) was assigned to each participant in consensus conference. Composite scores were created to summarize test performance on overall cognition, memory, attention executive function, and language. Multivariable logistic regression models were used to assess the sensitivity of each cognitive domain for discriminating three diagnostic categories. Adjustment was made for demographic variables (i. e., age, gender, education, primary language, and years living in the USA). RESULTS The sample included 67 normal, 37 MCI, and 12 AD participants. Performance in overall cognition, memory, and attention executive function was significantly worse in AD than in MCI, and performance in MCI was worse than in normal controls. Language performance followed a similar pattern, but differences did not achieve statistical significance among the three diagnostic groups. CONCLUSIONS This study highlights the need for cognitive assessment in elderly Chinese immigrants.
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Louis ED, Joyce JL, Cosentino S. Mind the gaps: What we don't know about cognitive impairment in essential tremor. Parkinsonism Relat Disord 2019; 63:10-19. [PMID: 30876840 DOI: 10.1016/j.parkreldis.2019.02.038] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Revised: 02/18/2019] [Accepted: 02/23/2019] [Indexed: 01/10/2023]
Abstract
INTRODUCTION Although the hallmark feature of essential tremor (ET) is tremor, there is growing appreciation that cognitive impairment also occurs, including increased prevalence of mild cognitive impairment (MCI) and increased prevalence and incidence of dementia. With emerging knowledge of ET-cognitive impairment, come fundamental questions regarding its course, bases, predictors and clinical outcomes. Studies in the general population and in Parkinson's disease (PD), a related movement disorder, offer a starting point from which to begin filling these clinically important knowledge gaps. METHODS A PubMed search (June 2018) identified articles for this review. RESULTS Much of our knowledge of cognitive impairment in ET is of the static condition (e.g., prevalence of cognitive impairment in ET), with nearly no information on its bases, predictors and dynamics (i.e., course, and clinical outcomes). In PD, where such data have been published, rates of cognitive decline and conversion to MCI/dementia are higher than in the general population. Predictors of cognitive change in PD and the general population have also been identified, yet they only partially overlap one another. CONCLUSION The predictors and dynamics of cognitive impairment have been investigated fairly extensively in the general population, to a somewhat lesser extent in PD, and are emerging only now in ET. We suggest that longitudinal studies specific to ET are needed, and we outline variables to be considered in these investigations. Increased knowledge of ET-cognitive impairment will facilitate meaningful counseling of patients and their families.
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Affiliation(s)
- Elan D Louis
- Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA.
| | - Jillian L Joyce
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Stephanie Cosentino
- Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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20
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Hilal S, Wolters FJ, Verbeek MM, Vanderstichele H, Ikram MK, Stoops E, Ikram MA, Vernooij MW. Plasma amyloid-β levels, cerebral atrophy and risk of dementia: a population-based study. ALZHEIMERS RESEARCH & THERAPY 2018; 10:63. [PMID: 29960604 PMCID: PMC6026500 DOI: 10.1186/s13195-018-0395-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Accepted: 05/30/2018] [Indexed: 12/15/2022]
Abstract
Background Plasma amyloid-β (Aβ) levels are increasingly studied as a potential accessible marker of cognitive impairment and dementia. However, it remains underexplored whether plasma Aβ levels including the novel Aβ peptide 1–38 (Aβ1–38) relate to preclinical markers of neurodegeneration and risk of dementia. We investigated the association of plasma Aβ1–38, Aβ1–40, and Aβ1–42 levels with imaging markers of neurodegeneration and risk of dementia in a prospective population-based study. Methods We analyzed plasma Aβ levels in 458 individuals from the Rotterdam Study. Brain volumes, including gray matter, white matter, and hippocampus, were computed on the basis of 1.5-T magnetic resonance imaging (MRI). Dementia and its subtypes were defined on the basis of internationally accepted criteria. Results A total of 458 individuals (mean age, 67.8 ± 7.7 yr; 232 [50.7%] women) with baseline MRI scans and incident dementia were included. The mean ± SD values of Aβ1–38, Aβ1–40, and Aβ1–42 (in pg/ml) were 19.4 ± 4.3, 186.1 ± 35.9, and 56.3 ± 6.2, respectively, at baseline. Lower plasma Aβ1–42 levels were associated with smaller hippocampal volume (mean difference in hippocampal volume per SD decrease in Aβ1–42 levels, − 0.13; 95% CI, − 0.23 to − 0.04; p = 0.007). After a mean follow-up of 14.8 years (SD, 4.9; range, 4.1–23.5 yr), 79 persons developed dementia, 64 of whom were diagnosed with Alzheimer’s disease (AD). Lower levels of Aβ1–38 and Aβ1–42 were associated with increased risk of dementia, specifically AD (HR for AD per SD decrease in Aβ1–38 levels, 1.39; 95% CI, 1.00–2.16; HR for AD per SD decrease in Aβ1–42 levels, 1.35; 95% CI, 1.05–1.75) after adjustment for age, sex, education, cardiovascular risk factors, apolipoprotein E ε4 allele carrier status, and other Aβ isoforms. Conclusions Our results show that lower plasma Aβ levels were associated with risk of dementia and incident AD. Moreover, lower plasma Aβ1–42 levels were related to smaller hippocampal volume. These results suggest that plasma Aβ1–38 and Aβ1–42 maybe useful biomarkers for identification of individuals at risk of dementia.
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Affiliation(s)
- Saima Hilal
- Department of Radiology and Nuclear Medicine, Erasmus University Medical Center, Office no. 2505, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands.,Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Frank J Wolters
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Marcel M Verbeek
- Department of Neurology and Laboratory Medicine, Donders Institute for Brain, Cognition and Behavior, Radboud Alzheimer Centre, Radboud University Medical Center, Nijmegen, The Netherlands
| | | | - M Kamran Ikram
- Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands.,Department of Neurology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | | | - M Arfan Ikram
- Department of Radiology and Nuclear Medicine, Erasmus University Medical Center, Office no. 2505, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands.,Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Meike W Vernooij
- Department of Radiology and Nuclear Medicine, Erasmus University Medical Center, Office no. 2505, Wytemaweg 80, 3015, CN, Rotterdam, The Netherlands. .,Department of Epidemiology, Erasmus University Medical Center, Rotterdam, The Netherlands.
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21
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Kim JH, Jung YS, Kim JW, Ha MS, Ha SM, Kim DY. Effects of aquatic and land-based exercises on amyloid beta, heat shock protein 27, and pulse wave velocity in elderly women. Exp Gerontol 2018; 108:62-68. [PMID: 29604402 DOI: 10.1016/j.exger.2018.03.024] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Revised: 02/12/2018] [Accepted: 03/27/2018] [Indexed: 11/17/2022]
Abstract
BACKGROUND Alzheimer's disease is a neurodegenerative brain disease resulting from the deterioration of neuronal cells and vascular dementia, the latter of which results from cerebrovascular disorders. Exercise is effective in preventing and treating degenerative brain diseases as it activates blood flow to the brain, increases nerve production in the hippocampus, and promotes the expression of synaptic plasticity-related proteins. Therefore, this study investigated the effects of 16-week aquatic and land-based exercise programs on amyloid beta (Aβ), heat shock protein (HSP) 27 levels, and pulse wave velocity (PWV). MATERIALS AND METHODS Forty elderly women, aged 60-70 years, voluntarily participated in the study. They were divided into control (n = 12), aquatic exercise (n = 14), and land-based exercise groups (n = 14). The variables of amyloid beta, heat shock protein 27, and pulse wave velocity were measured in all the participants before and after the 16-week study. RESULTS Significantly higher levels of serum HSP27 (p < 0.05) and significantly lower levels of vascular elasticity (p < 0.05) were found in the aquatic exercise group after 16 weeks of exercise compared with the control group. Aβ did not significantly differ between groups. Thirty minutes after the first exercise, Aβ in the aquatic exercise group (p < 0.01) and HSP27 in the land-based exercise group (p < 0.05) were significantly higher than the corresponding levels in the resting condition before exercise. 30 min after the last exercise, Aβ (p < 0.01) and HSP27 (p < 0.05) were significantly higher. CONCLUSIONS Aquatic and land-based exercises increased serum Aβ and HSP27 and decreased pulse wave velocity. Thus, they may play a positive role in the prevention of degenerative brain diseases and improvement of brain function in elderly people.
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Affiliation(s)
- Ji-Hyeon Kim
- Department of Physical Education, Pusan National University, Busan, South Korea
| | - Young-Suk Jung
- Department of Pharmacy, Pusan National University, Busan, South Korea
| | - Jong-Won Kim
- Department of Physical Education, Busan National University of Education, Busan, South Korea
| | - Min-Seong Ha
- Department of Physical Education, Pusan National University, Busan, South Korea
| | - Soo-Min Ha
- Department of Physical Education, Pusan National University, Busan, South Korea
| | - Do-Yeon Kim
- Department of Physical Education, Pusan National University, Busan, South Korea.
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22
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Hsu JL, Lee WJ, Liao YC, Wang SJ, Fuh JL. The clinical significance of plasma clusterin and Aβ in the longitudinal follow-up of patients with Alzheimer's disease. ALZHEIMERS RESEARCH & THERAPY 2017; 9:91. [PMID: 29169407 PMCID: PMC5701424 DOI: 10.1186/s13195-017-0319-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 11/06/2017] [Indexed: 12/29/2022]
Abstract
Background Clusterin and beta-amyloid (Aβ) are involved in the pathogenesis of Alzheimer’s disease (AD). The clinical significance of plasma clusterin and Aβ in AD progression remains controversial. Methods We recruited 322 patients with AD and 88 controls between August 2012 and June 2013. All participants were evaluated at baseline with a clinical assessment, Mini-Mental State Examination (MMSE), and Clinical Dementia Rating (CDR) scales. Patients with AD were evaluated annually with the MMSE and Neuropsychiatric Inventory (NPI) scale during the 2-year follow-up period. The levels of plasma clusterin, Aβ1–40, and Aβ1–42 at baseline were analyzed to study the longitudinal changes in the patient scores on the MMSE and NPI during the follow-up period. Results Patients in the highest tertile of plasma clusterin levels showed significantly lower MMSE scores than those in the lowest tertile (p = 0.04). After adjustment for multiple covariates using the generalized estimating equation analysis, there was a significant decrease in the MMSE scores over the 2-year follow-up period among AD patients in the highest tertile of plasma clusterin levels compared with those in the lowest tertile (−2.09, 95% confidence interval (CI) = −3.67 to −0.51, p = 0.01). In apolipoprotein E (ApoE)4-positive AD patients, baseline measurements of the ratio of plasma Aβ1–42/Aβ1–40 in the highest tertile predicted an increase in NPI agitation/aggression scores over the 2-year follow-up period (6.06, 95% CI = 1.20–10.62, p = 0.02). Conclusions Plasma clusterin could serve as a biomarker for the severity of cognitive decline. Plasma Aβ in ApoE4-positive AD could predict long-term agitation/aggression symptoms.
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Affiliation(s)
- Jung-Lung Hsu
- Graduate Institute of Humanities in Medicine, Taipei Medical University, Taipei, Taiwan.,Department of Neurology, Chang Gung Memorial Hospital Linkou Medical Center and College of Medicine, Chang-Gung University, Taoyuan, Taiwan.,Taipei Medical University Research Center for Brain and Consciousness, Shuang-Ho Hospital, New Taipei City, Taiwan
| | - Wei-Ju Lee
- Neurological Institute, Taichung Veterans General Hospital, Taichung, Taiwan.,Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Institute of Clinical Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan
| | - Yi-Chu Liao
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Brain Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan.,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, 112, Taiwan
| | - Shuu-Jiun Wang
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan. .,Brain Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan. .,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, 112, Taiwan.
| | - Jong-Ling Fuh
- Faculty of Medicine, National Yang-Ming University School of Medicine, Taipei, Taiwan. .,Brain Research Center, National Yang-Ming University School of Medicine, Taipei, Taiwan. .,Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taipei, 112, Taiwan.
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23
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Sano M, Zhu CW, Grossman H, Schimming C. Longitudinal Cognitive Profiles in Diabetes: Results From the National Alzheimer's Coordinating Center's Uniform Data. J Am Geriatr Soc 2017; 65:2198-2204. [PMID: 28771679 DOI: 10.1111/jgs.15014] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
BACKGROUND Diabetes is a risk factor for the development of cognitive impairment and possibly for accelerated progression to Alzheimer disease (AD) and other dementias, though the trajectory of cognitive decline in general and in specfic cognitive domains by diabetes is unclear. METHODS Using the National Alzheimer's Coordinating Center's Uniform Data Det (NACC-UDS) to identify cohorts of elders with normal cognition (N = 7,663) and mild cognitive impairment (MCI, N = 4,114), we compared overall cognitive composite and domain specific sub-scores and their progression over time between diabetic and non-diabetic subjects. RESULTS Diabetes was more common among those with MCI (14.7%) than among subjects who were cognitively normal (11.7%). In subjects who were cognitively normal, baseline cognitive composite scores, attention, and executive function sub-scores were lower in diabetics than non-diabetics (by 0.098, 0.066, and 0.015 points, respectively). Over time, cognitive composite score showed subtle worsening in non-diabetics (0.025 points every 6 months), with an additional worsening of 0.01 points every 6 months in diabetics compared to non-diabetics. In the MCI groups, baseline cognitive composite as well as attention and executive domain sub-scores were lower in diabetics than non-diabetics (by 0.078, 0.092, and 0.032 points, respectively). Over time, cognitive composite (by 0.103 points every 6 months) and all domain specific sub-scores showed subtle worsening in non-diabetics, but diabetics had significantly slower worsening than non-diabetics on both cognitive composite (by 0.028 points) and domain specific sub-scores. DISCUSSION Among elders, diabetes may be associated with lower cognitive performance, primarily in non-memory domains. However it is not associated with continued worsening, suggesting a static deficit with minimal memory involvement. This data suggest that diabetes may contribute more to a vascular profile of cognitive impairment than a profile more typical of AD.
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Affiliation(s)
- Mary Sano
- Alzheimer's Disease Research Center, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY.,James J Peters VAMC, Bronx, NY
| | - Carolyn W Zhu
- Alzheimer's Disease Research Center, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY.,James J Peters VAMC, Bronx, NY.,Department of Geriatrics and Palliative Medicine, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Hillel Grossman
- Alzheimer's Disease Research Center, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY.,James J Peters VAMC, Bronx, NY
| | - Corbett Schimming
- Alzheimer's Disease Research Center, Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY.,James J Peters VAMC, Bronx, NY
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24
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Vinothkumar G, Kedharnath C, Krishnakumar S, Sreedhar S, Preethikrishnan K, Dinesh S, Sundaram A, Balakrishnan D, Shivashekar G, Sureshkumar, Venkataraman P. Abnormal amyloid β 42 expression and increased oxidative stress in plasma of CKD patients with cognitive dysfunction: A small scale case control study comparison with Alzheimer's disease. BBA CLINICAL 2017; 8:20-27. [PMID: 28702365 PMCID: PMC5491400 DOI: 10.1016/j.bbacli.2017.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 06/02/2017] [Accepted: 06/20/2017] [Indexed: 01/31/2023]
Abstract
Background Cognitive dysfunction has been increasingly recognized in chronic kidney disease (CKD) patients. Senile plaques are important pathophysiological characteristic of cognitive dysfunction. The major component of plaques is the amyloid β (Aβ) peptide released from proteolytic cleavage of amyloid precursor protein (APP). Plasma Aβ has been a focus of the growing literature on blood based biomarkers for cognitive dysfunction. Oxidative stress is prevalent in CKD and it plays an important role in cognitive dysfunction. Increased oxidative stress leads to cause cleavage of APP and Aβ production. The aim of this study is to assess the antioxidant status and Aβ42 levels in plasma of CKD patients with cognitive dysfunction compared to CKD without cognitive dysfunction. Methods A total of 60 subjects divided into 30 CKD without cognitive dysfunction and 30 CKD with cognitive dysfunction based on neuropsychological assessment tests. To compare antioxidant status and Aβ42 levels in plasma, the following groups such as healthy subjects (n = 30), normocytic normochromic anemia (n = 30) and Alzheimer's disease (AD, n = 10) patients were also maintained. Plasma Superoxide dismutase (SOD), Catalase (CAT), Glutathione peroxidase (GPx), Reduced glutathione (GSH) and lipid peroxidation (LPO) were determined by spectrophotometrically. Aβ level was determined by immunoblotting method. The parameters were statistically compared with healthy, normocytic normochromic anemia and AD subjects. Results Like AD subjects, significantly increased Aβ and LPO level while decreased SOD, CAT, GPx and GSH levels were observed in plasma of CKD patients with cognitive dysfunction when compared to healthy, CKD without cognitive dysfunction and normocytic normochromic anemic subjects. Conclusion Results suggest that elevated plasma oxidative stress and Aβ were seen in CKD patients with cognitive dysfunction may be attributed to pathological changes within the brain. Cognitive dysfunction has been increasingly recognized in chronic kidney disease (CKD) patients. The major component of plaques is the amyloid β peptide released from proteolytic cleavage of amyloid precursor protein. Plasma Aβ has been a focus of the growing literature on blood based biomarkers for cognitive dysfunction. Oxidative stress is prevalent in CKD and it plays an important role in cognitive dysfunction. Increased oxidative stress leads to cause cleavage of APP and Aβ production.
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Affiliation(s)
- G Vinothkumar
- Department of Medical Research, SRM Medical College Hospital, SRM University, Chennai, India
| | - C Kedharnath
- Department of Nephrology, SRM Medical College Hospital, SRM University, Chennai, India
| | - S Krishnakumar
- Department of Nephrology, SRM Medical College Hospital, SRM University, Chennai, India
| | - S Sreedhar
- Department of Nephrology, SRM Medical College Hospital, SRM University, Chennai, India
| | - K Preethikrishnan
- Department of Clinical Psychology, SRM Medical College Hospital, SRM University, Chennai, India
| | - S Dinesh
- Department of Clinical Psychology, SRM Medical College Hospital, SRM University, Chennai, India
| | - A Sundaram
- Department of Medical Research, SRM Medical College Hospital, SRM University, Chennai, India
| | - D Balakrishnan
- Department of Medical Research, SRM Medical College Hospital, SRM University, Chennai, India
| | - G Shivashekar
- Department of Pathology, SRM Medical College Hospital, SRM University, Chennai, India
| | - Sureshkumar
- Department of Neurology, Balaji Medical College Hospital, Chrompet, Chennai, India
| | - P Venkataraman
- Department of Medical Research, SRM Medical College Hospital, SRM University, Chennai, India
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25
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Stillman CM, Lopez OL, Becker JT, Kuller LH, Mehta PD, Tracy RP, Erickson KI. Physical activity predicts reduced plasma β amyloid in the Cardiovascular Health Study. Ann Clin Transl Neurol 2017; 4:284-291. [PMID: 28491896 PMCID: PMC5420805 DOI: 10.1002/acn3.397] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 01/27/2023] Open
Abstract
Objective Higher levels of physical activity (PA) reduce the risk of cognitive impairment, but the underlying mechanisms are unclear. Using longitudinal data from the Cardiovascular Health Study, we examined whether PA predicted plasma Aβ levels and risk for cognitive decline 9–13 years later. Methods Linear and logistic regressions (controlling for APOE status, age, gender, body mass index, cardiovascular disease, brain white matter lesions, and cystatin C levels) tested associations between PA, Aβ, and cognitive impairment in a sample of 149 cognitively normal older adults (mean age 83 years). Results More PA at baseline predicted lower levels of Aβ 9–13 years later. Higher Aβ levels at year 9 predicted greater risk for cognitive impairment at year 13. Levels of Aβ at year 9 mediated the relationship between PA and cognitive impairment. Interpretation Greater PA may reduce plasma levels of a neurotoxic peptide at an age when the risk for cognitive impairment is especially high.
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Affiliation(s)
- Chelsea M Stillman
- Department of Psychiatry University of Pittsburgh School of Medicine Pittsburgh Pennsylvania
| | - Oscar L Lopez
- Department of Psychiatry University of Pittsburgh School of Medicine Pittsburgh Pennsylvania.,Department of Neurology University of Pittsburgh School of Medicine Pittsburgh Pennsylvania
| | - James T Becker
- Department of Psychiatry University of Pittsburgh School of Medicine Pittsburgh Pennsylvania.,Department of Neurology University of Pittsburgh School of Medicine Pittsburgh Pennsylvania.,Department of Psychology University of Pittsburgh Pittsburgh Pennsylvania
| | - Lewis H Kuller
- Graduate School of Public Health University of Pittsburgh Pittsburgh Pennsylvania
| | - Pankaj D Mehta
- New York State Institute for Basic Research in Developmental Disabilities Staten Island New York
| | - Russell P Tracy
- Department of Pathology & Laboratory Medicine University of Vermont College of Medicine Burlington Vermont
| | - Kirk I Erickson
- Department of Psychology University of Pittsburgh Pittsburgh Pennsylvania
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26
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Schütt T, Helboe L, Pedersen LØ, Waldemar G, Berendt M, Pedersen JT. Dogs with Cognitive Dysfunction as a Spontaneous Model for Early Alzheimer's Disease: A Translational Study of Neuropathological and Inflammatory Markers. J Alzheimers Dis 2017; 52:433-49. [PMID: 27003213 DOI: 10.3233/jad-151085] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Aged companion dogs with canine cognitive dysfunction (CCD) spontaneously develop varying degrees of progressive cognitive decline and particular neuropathological features correspondent to the changes associated with Alzheimer's disease (AD) in humans. The aim of the present study was to characterize certain aspects of neuropathology and inflammatory markers related to aging and CCD in dogs in comparison with human AD. Fifteen brains from aged dogs with normal cognitive function, mild cognitive impairment, or CCD were investigated and compared with two control brains from young dogs and brain sections from human AD subjects. The neuropathological investigations included evaluation of amyloid-β (Aβ) plaque deposition (N-terminally truncated and pyroglutamyl-modified Aβ included), tau pathology, and inflammatory markers in prefrontal cortex. Cortical Aβ deposition was found to be only of the diffuse subtype as no dense-core or neuritic plaques were found. The Aβ deposition followed a progressive pattern in four maturation stages. Accumulation of the Aβ peptide was also observed in the vessel walls. Both immunohistochemically and biochemically measured levels of Aβ pathology in prefrontal cortex showed a consistent positive correlation to age but not to cognitive deficit severity. No evidence of neurofibrillary tau pathology was found. The level of pro-inflammatory cytokines was generally low and showed no significant association to cognitive status. The findings of the present study support the senescent dog with spontaneous cognitive dysfunction as a valuable non-transgenic model for further investigations of the molecular events involved in the neurodegenerative processes associated with aging and early stage AD, especially the Aβ-related pathology.
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Affiliation(s)
- Trine Schütt
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.,Department of Neurodegeneration, H. Lundbeck A/S, Valby, Denmark
| | - Lone Helboe
- Department of Neurodegeneration, H. Lundbeck A/S, Valby, Denmark
| | | | - Gunhild Waldemar
- Danish Dementia Research Centre, Rigshospitalet, University of Copenhagen, Denmark
| | - Mette Berendt
- Department of Veterinary Clinical and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark
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27
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Gronewold J, Todica O, Klafki HW, Seidel UK, Kaltwasser B, Wiltfang J, Kribben A, Bruck H, Hermann DM. Association of Plasma β-Amyloid with Cognitive Performance and Decline in Chronic Kidney Disease. Mol Neurobiol 2016; 54:7194-7203. [PMID: 27796755 DOI: 10.1007/s12035-016-0243-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 10/18/2016] [Indexed: 12/31/2022]
Abstract
Decreased β-amyloid (Aβ) clearance from the brain has been suggested to contribute to cerebral Aβ accumulation in Alzheimer's disease. Based on the idea of a dynamic Aβ equilibrium in different body compartments, plasma Aβ levels have been investigated as biomarker candidates for preclinical Alzheimer's pathology, yet with inconsistent results. Since the kidneys are involved in Aβ elimination from the blood, we evaluated how chronic kidney disease (CKD) affects the association between plasma Aβ and cognitive deficits and cognitive decline. In 28 CKD patients, stages 3-5D, and 26 control subjects with comparable vascular risk profile from the New Tools for the Prevention of Cardiovascular Disease in Chronic Kidney Disease (NTCVD) cohort, plasma total Aβ was determined with a highly sensitive electrochemiluminescence immunoassay. Cognition was evaluated using a comprehensive battery of ten neuropsychological tests at baseline and 2-year follow-up. Subjects with high plasma Aβ level (above median) demonstrated a significantly worse baseline cognitive performance than subjects exhibiting low Aβ level (summary score of global cognitive performance at baseline z = -0.46 ± 0.76 vs z = -0.08 ± 0.57, p = 0.045). Cognitive performance moderately decreased over the 2-year follow-up in subjects with high plasma Aβ level (Δz = -0.13 ± 0.51), but increased in subjects with low plasma Aβ level (Δz = 0.16 ± 0.41, p = 0.023). In linear regression analyses, baseline plasma Aβ was significantly associated with cognitive decline both in unadjusted analyses (β = -0.28, 95% CI = -0.55 to -0.01) and analyses adjusted for age (β = -0.27, 95% CI = -0.54 to -0.01). Our results suggest the utility of plasma Aβ level in predicting cognitive decline in patients suffering from CKD.
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Affiliation(s)
- Janine Gronewold
- Department of Neurology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany
| | - Olga Todica
- Department of Neurology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany
| | - Hans-Wolfgang Klafki
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen, von-Siebold-Straße 5, 37075, Goettingen, Germany
| | - Ulla K Seidel
- Department of Neurology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany
| | - Britta Kaltwasser
- Department of Neurology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany
| | - Jens Wiltfang
- Department of Psychiatry and Psychotherapy, University Medical Center Goettingen, von-Siebold-Straße 5, 37075, Goettingen, Germany
| | - Andreas Kribben
- Department of Nephrology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany
| | - Heike Bruck
- Department of Nephrology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany
| | - Dirk M Hermann
- Department of Neurology, University Hospital Essen, Hufelandstraße 55, 45122, Essen, Germany.
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28
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Cantero JL, Iglesias JE, Van Leemput K, Atienza M. Regional Hippocampal Atrophy and Higher Levels of Plasma Amyloid-Beta Are Associated With Subjective Memory Complaints in Nondemented Elderly Subjects. J Gerontol A Biol Sci Med Sci 2016; 71:1210-5. [PMID: 26946100 PMCID: PMC4978360 DOI: 10.1093/gerona/glw022] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 01/29/2016] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Evidence suggests a link between the presence of subjective memory complaints (SMC) and lower volume of the hippocampus, one of the first regions to show neuropathological lesions in Alzheimer's disease. However, it remains unknown whether this pattern of hippocampal atrophy is regionally specific and whether SMC are also paralleled by changes in peripheral levels of amyloid-beta (Aβ). METHODS The volume of hippocampal subregions and plasma Aβ levels were cross-sectionally compared between elderly individuals with (SMC(+); N = 47) and without SMC (SMC(-); N = 48). Significant volume differences in hippocampal subregions were further correlated with plasma Aβ levels and with objective memory performance. RESULTS Individuals with SMC exhibited significantly higher Aβ1-42 concentrations and lower volumes of CA1, CA4, dentate gyrus, and molecular layer compared with SMC(-) participants. Regression analyses further showed significant associations between lower volume of the dentate gyrus and both poorer memory performance and higher plasma Aβ1-42 levels in SMC(+) participants. CONCLUSIONS The presence of SMC, lower volumes of specific hippocampal regions, and higher plasma Aβ1-42 levels could be conditions associated with aging vulnerability. If such associations are confirmed in longitudinal studies, the combination may be markers recommending clinical follow-up in nondemented older adults.
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Affiliation(s)
- Jose L Cantero
- Laboratory of Functional Neuroscience, CIBERNED (Network Center for Biomedical Research in Neurodegenerative Diseases), Pablo de Olavide University, Seville, Spain.
| | - Juan E Iglesias
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston. Basque Center on Cognition, Brain and Language, San Sebastian, Spain
| | - Koen Van Leemput
- Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Boston. Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby, Denmark
| | - Mercedes Atienza
- Laboratory of Functional Neuroscience, CIBERNED (Network Center for Biomedical Research in Neurodegenerative Diseases), Pablo de Olavide University, Seville, Spain
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29
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Shin J, Doraiswamy PM. Underrepresentation of African-Americans in Alzheimer's Trials: A Call for Affirmative Action. Front Aging Neurosci 2016; 8:123. [PMID: 27375473 PMCID: PMC4891330 DOI: 10.3389/fnagi.2016.00123] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 05/13/2016] [Indexed: 11/18/2022] Open
Affiliation(s)
- Jaewook Shin
- Division of Translational Neuroscience, Department of Psychiatry, Duke University Medical CenterDurham, NC, USA; Duke Institute for Brain SciencesDurham, NC, USA; Duke Center for the Study of Aging and Human DevelopmentDurham, NC, USA
| | - P Murali Doraiswamy
- Division of Translational Neuroscience, Department of Psychiatry, Duke University Medical CenterDurham, NC, USA; Duke Institute for Brain SciencesDurham, NC, USA
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Ballard C, Mobley W, Hardy J, Williams G, Corbett A. Dementia in Down's syndrome. Lancet Neurol 2016; 15:622-36. [PMID: 27302127 DOI: 10.1016/s1474-4422(16)00063-6] [Citation(s) in RCA: 144] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 01/22/2016] [Accepted: 02/08/2016] [Indexed: 12/14/2022]
Abstract
Down's syndrome is the most common genetic cause of learning difficulties, and individuals with this condition represent the largest group of people with dementia under the age of 50 years. Genetic drivers result in a high frequency of Alzheimer's pathology in these individuals, evident from neuroimaging, biomarker, and neuropathological findings, and a high incidence of cognitive decline and dementia. However, cognitive assessment is challenging, and diagnostic methods have not been fully validated for use in these patients; hence, early diagnosis remains difficult. Evidence regarding the benefits of cholinesterase inhibitors and other therapeutic options to treat or delay progressive cognitive decline or dementia is very scarce. Despite close similarities with late-onset Alzheimer's disease, individuals with Down's syndrome respond differently to treatment, and a targeted approach to drug development is thus necessary. Genetic and preclinical studies offer opportunities for treatment development, and potential therapies have been identified using these approaches.
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Affiliation(s)
- Clive Ballard
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK.
| | - William Mobley
- Center for Neural Circuits and Behavior, School of Medicine, University of California San Diego, San Diego, CA, USA
| | - John Hardy
- Department of Molecular Neuroscience, University College London, London, UK
| | - Gareth Williams
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
| | - Anne Corbett
- Wolfson Centre for Age-Related Diseases, King's College London, London, UK
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The Alzheimer's Disease Neuroimaging Initiative 2 Biomarker Core: A review of progress and plans. Alzheimers Dement 2016; 11:772-91. [PMID: 26194312 DOI: 10.1016/j.jalz.2015.05.003] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Revised: 05/04/2015] [Accepted: 05/05/2015] [Indexed: 11/20/2022]
Abstract
INTRODUCTION We describe Alzheimer's Disease Neuroimaging Initiative (ADNI) Biomarker Core progress including: the Biobank; cerebrospinal fluid (CSF) amyloid beta (Aβ1-42), t-tau, and p-tau181 analytical performance, definition of Alzheimer's disease (AD) profile for plaque, and tangle burden detection and increased risk for progression to AD; AD disease heterogeneity; progress in standardization; and new studies using ADNI biofluids. METHODS Review publications authored or coauthored by ADNI Biomarker core faculty and selected non-ADNI studies to deepen the understanding and interpretation of CSF Aβ1-42, t-tau, and p-tau181 data. RESULTS CSF AD biomarker measurements with the qualified AlzBio3 immunoassay detects neuropathologic AD hallmarks in preclinical and prodromal disease stages, based on CSF studies in non-ADNI living subjects followed by the autopsy confirmation of AD. Collaboration across ADNI cores generated the temporal ordering model of AD biomarkers varying across individuals because of genetic/environmental factors that increase/decrease resilience to AD pathologies. DISCUSSION Further studies will refine this model and enable the use of biomarkers studied in ADNI clinically and in disease-modifying therapeutic trials.
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Shanthi KB, Krishnan S, Rani P. A systematic review and meta-analysis of plasma amyloid 1-42 and tau as biomarkers for Alzheimer's disease. SAGE Open Med 2015; 3:2050312115598250. [PMID: 26770797 PMCID: PMC4679337 DOI: 10.1177/2050312115598250] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Accepted: 06/27/2015] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVE Amyloid 1-42 (Aβ42) and tau in cerebrospinal fluid are currently used as markers for diagnosis of Alzheimer's disease. Conflicting reports exist regarding their plasma levels in Alzheimer's disease patients. A meta-analysis was performed to statistically validate the use of plasma Aβ42 and tau as biomarkers for Alzheimer's disease. METHODS Different databases were searched using the search key: (amyloid OR amyloid1-42 OR Aβ42) AND (tau OR total tau) AND plasma AND (alzheimer's OR alzheimer's disease), and for databases not accepting boolean search, records were retrieved using the search key: plasma + amyloid + tau + alzheimer's. A total of 1880 articles for Aβ42 and 1508 articles for tau were shortlisted. The abstracts were screened, and 69 articles reporting plasma Aβ42 levels and 6 articles reporting plasma tau were identified. After exclusion, 25 studies reporting plasma Aβ42 and 6 studies reporting total tau were analysed in Review Manager version 5.2 using weighted mean difference method, and the bias between studies was assessed using the funnel plot. RESULTS Plasma Aβ42 and tau did not vary significantly between Alzheimer's disease patients and controls. The funnel plot showed that there was no bias between studies for Aβ42, while possible bias existed for tau due to availability of limited studies. CONCLUSION This analysis pinpoints that plasma Aβ42 and tau could not serve as reliable markers independently for diagnosis of Alzheimer's disease and a cohort study with age, sex and apolipoprotein E correction is warranted for their possible use as Alzheimer's disease markers.
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Affiliation(s)
| | - Sreeram Krishnan
- Department of Biotechnology, PSG College of Technology, Coimbatore, India
| | - P Rani
- Department of Biotechnology, PSG College of Technology, Coimbatore, India
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Subash S, Essa MM, Braidy N, Awlad-Thani K, Vaishnav R, Al-Adawi S, Al-Asmi A, Guillemin GJ. Diet rich in date palm fruits improves memory, learning and reduces beta amyloid in transgenic mouse model of Alzheimer's disease. J Ayurveda Integr Med 2015; 6:111-20. [PMID: 26167001 PMCID: PMC4484046 DOI: 10.4103/0975-9476.159073] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/09/2014] [Accepted: 07/22/2014] [Indexed: 12/30/2022] Open
Abstract
Background: At present, the treatment options available to delay the onset or slow down the progression of Alzheimer's disease (AD) are not effective. Recent studies have suggested that diet and lifestyle factors may represent protective strategies to minimize the risk of developing AD. Date palm fruits are a good source of dietary fiber and are rich in total phenolics and natural antioxidants, such as anthocyanins, ferulic acid, protocatechuic acid and caffeic acid. These polyphenolic compounds have been shown to be neuroprotective in different model systems. Objective: We investigated whether dietary supplementation with 2% and 4% date palm fruits (grown in Oman) could reduce cognitive and behavioral deficits in a transgenic mouse model for AD (amyloid precursor protein [APPsw]/Tg2576). Materials and Methods: The experimental groups of APP-transgenic mice from the age of 4 months were fed custom-mix diets (pellets) containing 2% and 4% date fruits. We assessed spatial memory and learning ability, psychomotor coordination, and anxiety-related behavior in all the animals at the age of 4 months and after 14 months of treatment using the Morris water maze test, rota-rod test, elevated plus maze test, and open-field test. We have also analyzed the levels of amyloid beta (Aβ) protein (1–40 and 1–42) in plasma of control and experimental animals. Results: Standard diet-fed Tg mice showed significant memory deficits, increased anxiety-related behavior, and severe impairment in spatial learning ability, position discrimination learning ability and motor coordination when compared to wild-type on the same diet and Tg mice fed 2% and 4% date supplementation at the age of 18 months. The levels of both Aβ proteins were significantly lowered in date fruits supplemented groups than the Tg mice without the diet supplement. The neuroprotective effect offered by 4% date fruits diet to AD mice is higher than 2% date fruits diet. Conclusions: Our results suggest that date fruits dietary supplementation may have beneficial effects in lowering the risk, delaying the onset or slowing down the progression of AD.
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Affiliation(s)
- Selvaraju Subash
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Muscat, Oman ; Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman
| | - Musthafa Mohamed Essa
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Muscat, Oman ; Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman
| | - Nady Braidy
- Centre for Healthy Brain Ageing, School of Psychiatry, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia
| | - Kathyia Awlad-Thani
- Department of Food Science and Nutrition, College of Agricultural and Marine Sciences, Muscat, Oman ; Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman
| | - Ragini Vaishnav
- Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman ; Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman, Oman
| | - Samir Al-Adawi
- Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman ; Behavioral Medicine, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman, Oman
| | - Abdullah Al-Asmi
- Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman ; Neurology Unit - Medicine, College of Medicine and Health Sciences, Macquarie University, NSW, Australia
| | - Gilles J Guillemin
- Neuropharmacology Group, MND and Neurodegenerative Diseases Research Centre, Macquarie University, NSW, Australia
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Llado-Saz S, Atienza M, Cantero JL. Increased levels of plasma amyloid-beta are related to cortical thinning and cognitive decline in cognitively normal elderly subjects. Neurobiol Aging 2015; 36:2791-7. [PMID: 26182906 DOI: 10.1016/j.neurobiolaging.2015.06.023] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Revised: 06/14/2015] [Accepted: 06/17/2015] [Indexed: 12/30/2022]
Abstract
Plasma levels of circulating amyloid-beta (Aβ) peptides are of particular interest in Alzheimer' disease, but little is known about cognitive and cortical correlates of peripheral Aβ levels in normal aging. Here, we compared cognitive functioning, vascular risk factors, and patterns of cortical thickness between cognitively intact elderly subjects with low (N = 60) and high (N = 60) plasma Aβ levels (cutoffs: 225 pg/mL and 23 pg/mL for Aβ1-40 and Aβ1-42, respectively). Overall, subjects with high Aβ levels showed lower cognitive performance and thinner cortex than those with low Aβ levels. More specifically, subjects with high Aβ1-40 showed bilateral thinning of the prefrontal cortex, poorer objective memory, slower processing speed, and lower nonverbal reasoning skills, whereas subjects with high Aβ1-42 had thinner temporal lobe, poorer everyday memory, and increased levels of homocysteine. Overall, these results suggest that high plasma Aβ levels in normal elderly subjects are associated with subclinical markers of vulnerable aging, which may be helpful at predicting different trajectories of aging in cognitively intact older adults.
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Affiliation(s)
- Sandra Llado-Saz
- Laboratory of Functional Neuroscience, Spanish Network of Excellence for Research on Neurodegenerative Diseases (CIBERNED), Pablo de Olavide University, Seville, Spain
| | - Mercedes Atienza
- Laboratory of Functional Neuroscience, Spanish Network of Excellence for Research on Neurodegenerative Diseases (CIBERNED), Pablo de Olavide University, Seville, Spain
| | - Jose L Cantero
- Laboratory of Functional Neuroscience, Spanish Network of Excellence for Research on Neurodegenerative Diseases (CIBERNED), Pablo de Olavide University, Seville, Spain.
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Lu H, Zhu XC, Jiang T, Yu JT, Tan L. Body fluid biomarkers in Alzheimer's disease. ANNALS OF TRANSLATIONAL MEDICINE 2015; 3:70. [PMID: 25992369 DOI: 10.3978/j.issn.2305-5839.2015.02.13] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Accepted: 02/03/2015] [Indexed: 01/09/2023]
Abstract
A heterogeneous and slowly progressive disease with extracellular amyloid-β (Aβ) deposits and intracellular hyperphosphorylated tau protein aggregates, Alzheimer's disease (AD) is already a hard nut to crack, featured with cognitive decline and memory lapse. Body fluid biomarkers are proved to be useful in exploring further study of AD, might benefit for a full comprehension of the etiopathogenesis, an improved precision of the prognosis and diagnosis, and a positive response of treatments. The cerebrospinal fluid biomarkers Aβ, total tau, and hyperphosphorylated tau reflect the main pathologic changes of AD. We also review data from several novel biomarkers, such as, β-site APP cleaving enzyme 1, soluble amyloid precursor proteins α and β, soluble Aβ oligomers and so on, which are associated with the occurrence and deterioration of this disease and couldn't be ignored. The rationale for the clinical use of those biomarkers, the challenges faced with and the properties of the most appropriate biomarkers are also summarized in the paper. We aim to find several ideal biomarkers to improve the diagnosis and optimize the treatment respectively.
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Affiliation(s)
- Huan Lu
- 1 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Nanjing 210029, China ; 2 Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210029, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266001, China ; 4 Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Xi-Chen Zhu
- 1 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Nanjing 210029, China ; 2 Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210029, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266001, China ; 4 Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Teng Jiang
- 1 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Nanjing 210029, China ; 2 Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210029, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266001, China ; 4 Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Jin-Tai Yu
- 1 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Nanjing 210029, China ; 2 Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210029, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266001, China ; 4 Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158, USA
| | - Lan Tan
- 1 Department of Neurology, Qingdao Municipal Hospital, Nanjing Medical University, Nanjing 210029, China ; 2 Department of Neurology, Nanjing First Hospital, Nanjing Medical University, Nanjing 210029, China ; 3 Department of Neurology, Qingdao Municipal Hospital, School of Medicine, Qingdao University, Qingdao 266001, China ; 4 Memory and Aging Center, Department of Neurology, University of California, San Francisco, CA 94158, USA
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Essa MM, Subash S, Akbar M, Al-Adawi S, Guillemin GJ. Long-term dietary supplementation of pomegranates, figs and dates alleviate neuroinflammation in a transgenic mouse model of Alzheimer's disease. PLoS One 2015; 10:e0120964. [PMID: 25807081 PMCID: PMC4373715 DOI: 10.1371/journal.pone.0120964] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Accepted: 01/27/2015] [Indexed: 01/08/2023] Open
Abstract
Alzheimer's disease (AD) is a devastating age-related neurodegenerative disease with no specific treatment at present. The APPsw/Tg2576 mice exhibit age-related deterioration in memory and learning as well as amyloid-beta (Aβ) accumulation, and this mouse strain is considered an effective model for studying the mechanism of accelerated brain aging and senescence. The present study was aimed to investigate the beneficial effects of dietary supplements pomegranate, figs, or the dates on suppressing inflammatory cytokines in APPsw/Tg2576 mice. Changes in the plasma cytokines and Aβ, ATP, and inflammatory cytokines were investigated in the brain of transgenic mice. Significantly enhanced levels of inflammatory cytokines IL-1β, IL-2, IL-3, IL-4, IL-5, IL-6, IL-9, IL-10, TNF-α and Eotaxin activity were decreased by administration of the diet supplements containing pomegranates, figs, or dates. In addition, putative delays in the formation of senile plaques, as indicated by a decreasing tendency of brain Aβ1-40 and Aβ1-42 contents, were observed. Thus, novel results mediated by reducing inflammatory cytokines during aging may represent one mechanism by which these supplements exert their beneficial effects against neurodegenerative diseases such as AD.
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Affiliation(s)
- Musthafa Mohamed Essa
- Dept of Food Science and Nutrition, College of Agriculture and Marine Sciences, Sultan Qaboos University, Muscat, Oman
- Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman
- Neuropharmacology group, MND and Neurodegenerative Diseases Research Centre, Macquarie University, Sydney, NSW, Australia
| | - Selvaraju Subash
- Dept of Food Science and Nutrition, College of Agriculture and Marine Sciences, Sultan Qaboos University, Muscat, Oman
- Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman
| | - Mohammed Akbar
- Section of Molecular Pharmacology and Toxicology, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, MD, United States of America
| | - Samir Al-Adawi
- Ageing and Dementia Research Group, Sultan Qaboos University, Muscat, Oman
- College of Medicine and Health Sciences, Sultan Qaboos University, Muscat, Oman
| | - Gilles J. Guillemin
- Neuropharmacology group, MND and Neurodegenerative Diseases Research Centre, Macquarie University, Sydney, NSW, Australia
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François M, Leifert W, Martins R, Thomas P, Fenech M. Biomarkers of Alzheimer's disease risk in peripheral tissues; focus on buccal cells. Curr Alzheimer Res 2015; 11:519-31. [PMID: 24938500 PMCID: PMC4166904 DOI: 10.2174/1567205011666140618103827] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Revised: 05/26/2014] [Accepted: 06/16/2014] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is a progressive degenerative disorder of the brain and is the most common form of dementia. To-date no simple, inexpensive and minimally invasive procedure is available to confirm with certainty the early diagnosis of AD prior to the manifestations of symptoms characteristic of the disease. Therefore, if population screening of individuals is to be performed, more suitable, easily accessible tissues would need to be used for a diagnostic test that would identify those who exhibit cellular pathology indicative of mild cognitive impairment (MCI) and AD risk so that they can be prioritized for primary prevention. This need for minimally invasive tests could be achieved by targeting surrogate tissues, since it is now well recognized that AD is not only a disorder restricted to pathology and biomarkers within the brain. Human buccal cells for instance are accessible in a minimally invasive manner, and exhibit cytological and nuclear morphologies that may be indicative of accelerated ageing or neurodegenerative disorders such as AD. However, to our knowledge there is no review available in the literature covering the biology of buccal cells and their applications in AD biomarker research. Therefore, the aim of this review is to summarize some of the main findings of biomarkers reported for AD in peripheral tissues, with a further focus on the rationale for the use of the buccal mucosa (BM) for biomarkers of AD and the evidence to date of changes exhibited in buccal cells with AD.
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Affiliation(s)
| | | | | | | | - Michael Fenech
- CSIRO Animal, Food and Health Sciences, Gate 13, Kintore Ave, Adelaide, South Australia, 5000, Australia.
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Abbasowa L, Heegaard NHH. A systematic review of amyloid-β peptides as putative mediators of the association between affective disorders and Alzheimer׳s disease. J Affect Disord 2014; 168:167-83. [PMID: 25058309 DOI: 10.1016/j.jad.2014.06.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 06/27/2014] [Accepted: 06/28/2014] [Indexed: 11/26/2022]
Abstract
BACKGROUND Affective disorders are associated with an increased occurrence of cognitive deficits and have been linked to cognitive impairment and Alzheimer׳s disease. The putative molecular mechanisms involved in these associations are however not clear. The aim of this systematic review was to explore clinically founded evidence for amyloid-β peptides in cerebrospinal fluid and blood as putative biomarkers for affective disorders. METHOD Systematic searches in Embase and PubMed databases yielded 23 eligible, observational studies. RESULTS Despite inconsistencies that were partly ascribed to the application of different assay formats, study results indicate a potentially altered amyloid-β metabolism in affective disorder. LIMITATIONS Since most studies used a cross-sectional design, causality is difficult to establish. Moreover, methodological rigor of included studies varied and several studies were limited by very low sample numbers. Finally, different assays for amyloid-β were utilized in the different studies, thus hampering comparisons. CONCLUSION To unravel possible risk relations and causalities between affective disorder and Alzheimer׳s disease and to determine how amyloid-β concentrations change over time and are associated with cognition as well as affective symptomatology, future research should include prospective, longitudinal studies, implemented in large study populations, where peripheral and central amyloid-β ratios are quantified concomitantly and continuously across various affective phases. Also, to enable inter-survey comparisons, the use of standardized pre-analytical/analytical procedures is crucial.
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Affiliation(s)
- Leda Abbasowa
- Department of Medicine, Kabbeltoft 25, DK-7100 Vejle, Denmark.
| | - Niels H H Heegaard
- Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, University of Southern Denmark, Denmark; Department of Clinical Biochemistry, Immunology & Genetics, Statens Serum Institut, Copenhagen, Denmark
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Subash S, Essa MM, Al-Asmi A, Al-Adawi S, Vaishnav R. Chronic dietary supplementation of 4% figs on the modification of oxidative stress in Alzheimer's disease transgenic mouse model. BIOMED RESEARCH INTERNATIONAL 2014; 2014:546357. [PMID: 25050360 PMCID: PMC4090508 DOI: 10.1155/2014/546357] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Revised: 05/19/2014] [Accepted: 05/28/2014] [Indexed: 01/24/2023]
Abstract
We assessed the changes in the plasma Aβ, oxidative stress/antioxidants, and membrane bound enzymes in the cerebral cortex and hippocampus of Alzheimer's disease (AD) transgenic mice (Tg2576) after dietary supplementation of Omani figs fruits for 15 months along with spatial memory and learning test. AD Tg mice on control diet without figs showed significant impairment in spatial learning ability compared to the wild-type mice on same diet and figs fed Tg mice as well. Significant increase in oxidative stress and reduced antioxidant status were observed in AD Tg mice. 4% figs treated AD Tg mice significantly attenuated oxidative damage, as evident by decreased lipid peroxidation and protein carbonyls and restoration of antioxidant status. Altered activities of membrane bound enzymes (Na(+) K(+) ATPase and acetylcholinesterase (AChE)) in AD Tg mice brain regions and was restored by figs treatment. Further, figs supplementation might be able to decrease the plasma levels of Aβ (1-40, 1-42) significantly in Tg mice suggesting a putative delay in the formation of plaques, which might be due to the presence of high natural antioxidants in figs. But this study warrants further extensive investigation to find a novel lead for a therapeutic target for AD from figs.
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Affiliation(s)
- Selvaraju Subash
- Department of Food Science and Nutrition, College of Agriculture and Marine Sciences, P.O. Box 34, Sultan Qaboos University, Al-Khoud, 123 Muscat, Oman
- Ageing and Dementia Research Group, Sultan Qaboos University, 123 Muscat, Oman
| | - Musthafa Mohamed Essa
- Department of Food Science and Nutrition, College of Agriculture and Marine Sciences, P.O. Box 34, Sultan Qaboos University, Al-Khoud, 123 Muscat, Oman
- Ageing and Dementia Research Group, Sultan Qaboos University, 123 Muscat, Oman
| | - Abdullah Al-Asmi
- Ageing and Dementia Research Group, Sultan Qaboos University, 123 Muscat, Oman
- College of Medicine and Health Sciences, Sultan Qaboos University, 123 Muscat, Oman
| | - Samir Al-Adawi
- Ageing and Dementia Research Group, Sultan Qaboos University, 123 Muscat, Oman
- College of Medicine and Health Sciences, Sultan Qaboos University, 123 Muscat, Oman
| | - Ragini Vaishnav
- Ageing and Dementia Research Group, Sultan Qaboos University, 123 Muscat, Oman
- Oman Assistant Pharmacy Institute, Directorate General of Education and Training, Ministry of Health, P.O. Box 1928, 114 Muttrah, Oman
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A blood-based predictor for neocortical Aβ burden in Alzheimer's disease: results from the AIBL study. Mol Psychiatry 2014; 19:519-26. [PMID: 23628985 DOI: 10.1038/mp.2013.40] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 01/30/2013] [Accepted: 03/06/2013] [Indexed: 12/28/2022]
Abstract
Dementia is a global epidemic with Alzheimer's disease (AD) being the leading cause. Early identification of patients at risk of developing AD is now becoming an international priority. Neocortical Aβ (extracellular β-amyloid) burden (NAB), as assessed by positron emission tomography (PET), represents one such marker for early identification. These scans are expensive and are not widely available, thus, there is a need for cheaper and more widely accessible alternatives. Addressing this need, a blood biomarker-based signature having efficacy for the prediction of NAB and which can be easily adapted for population screening is described. Blood data (176 analytes measured in plasma) and Pittsburgh Compound B (PiB)-PET measurements from 273 participants from the Australian Imaging, Biomarkers and Lifestyle (AIBL) study were utilised. Univariate analysis was conducted to assess the difference of plasma measures between high and low NAB groups, and cross-validated machine-learning models were generated for predicting NAB. These models were applied to 817 non-imaged AIBL subjects and 82 subjects from the Alzheimer's Disease Neuroimaging Initiative (ADNI) for validation. Five analytes showed significant difference between subjects with high compared to low NAB. A machine-learning model (based on nine markers) achieved sensitivity and specificity of 80 and 82%, respectively, for predicting NAB. Validation using the ADNI cohort yielded similar results (sensitivity 79% and specificity 76%). These results show that a panel of blood-based biomarkers is able to accurately predict NAB, supporting the hypothesis for a relationship between a blood-based signature and Aβ accumulation, therefore, providing a platform for developing a population-based screen.
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Abstract
BACKGROUND Numerous studies suggest that higher coffee consumption may reduce the rate of aging-related cognitive decline in women. It is thus potentially a cheap and widely available candidate for prevention programs provided its mechanism may be adequately understood. The assumed effect is that of reduced amyloid deposition, however, alternative pathways notably by reducing depression and diabetes type 2 risk have not been considered. METHODS A population study of 1,193 elderly persons examining depressive symptomatology, caffeine consumption, fasting glucose levels, type 2 diabetes onset, serum amyloid, and factors known to affect cognitive performance was used to explore alternative causal models. RESULTS Higher caffeine consumption was found to be associated with decreased risk of incident diabetes in men (HR = 0.64; 95% CI 0.42-0.97) and increased risk in women (HR = 1.51; 95% CI 1.08-2.11). No association was found with incident depression. While in the total sample lower ratio Aβ42/Aβ40 levels (OR = 1.36, 95% CI 1.05-1.77, p = 0.02) were found in high caffeine consumers, this failed to reach significance when the analyses were stratified by gender. CONCLUSIONS We found no evidence that reduced risk of cognitive decline in women with high caffeine consumption is moderated or confounded by diabetes or depression. The evidence of an association with plasma beta amyloid could not be clearly demonstrated. Insufficient proof of causal mechanisms currently precludes the recommendation of coffee consumption as a public health measure. Further research should focus on the high estrogen content of coffee as a plausible alternative explanation.
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Sarasa L, Allué JA, Pesini P, González-Martínez Á, Sarasa M. Identification of β-amyloid species in canine cerebrospinal fluid by mass spectrometry. Neurobiol Aging 2013; 34:2125-32. [DOI: 10.1016/j.neurobiolaging.2013.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 02/12/2013] [Accepted: 03/11/2013] [Indexed: 01/20/2023]
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Rembach A, Ryan TM, Roberts BR, Doecke JD, Wilson WJ, Watt AD, Barnham KJ, Masters CL. Progress towards a consensus on biomarkers for Alzheimer’s disease: a review of peripheral analytes. Biomark Med 2013; 7:641-62. [DOI: 10.2217/bmm.13.59] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Alzheimer’s disease (AD) is the most common cause of dementia in the elderly population and attempts to develop therapies have been unsuccessful because there is no means to target an effective therapeutic window. CNS biomarkers are insightful but impractical for high-throughput population-based screening. Therefore, a peripheral, blood-based biomarker for AD would significantly improve early diagnosis, potentially enable presymptomatic detection and facilitate effective targeting of disease-modifying treatments. The various constituents of blood, including plasma, platelets and cellular fractions, are now being systematically explored as a pool of putative peripheral biomarkers for AD. In this review we cover some less known peripheral biomarkers and highlight the latest developments for their clinical application.
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Affiliation(s)
- Alan Rembach
- The Mental Health Research Institute, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3010, Australia.
| | - Tim M Ryan
- The Mental Health Research Institute, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3010, Australia
| | - Blaine R Roberts
- The Mental Health Research Institute, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3010, Australia
| | - James D Doecke
- The Australian e-Health Research Centre, Herston, Queensland, 4029, Australia
- CSIRO Preventative Health National Research Flagship, North Ryde, New South Wales, 2113, Australia
| | - William J Wilson
- CSIRO Preventative Health National Research Flagship, North Ryde, New South Wales, 2113, Australia
| | - Andrew D Watt
- The Mental Health Research Institute, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3010, Australia
| | - Kevin J Barnham
- The Mental Health Research Institute, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3010, Australia
| | - Colin L Masters
- The Mental Health Research Institute, The University of Melbourne, Kenneth Myer Building, 30 Royal Parade, Parkville, Victoria, 3010, Australia
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Brown BM, Peiffer JJ, Taddei K, Lui JK, Laws SM, Gupta VB, Taddei T, Ward VK, Rodrigues MA, Burnham S, Rainey-Smith SR, Villemagne VL, Bush A, Ellis KA, Masters CL, Ames D, Macaulay SL, Szoeke C, Rowe CC, Martins RN, Martins RN. Physical activity and amyloid-β plasma and brain levels: results from the Australian Imaging, Biomarkers and Lifestyle Study of Ageing. Mol Psychiatry 2013; 18:875-81. [PMID: 22889922 DOI: 10.1038/mp.2012.107] [Citation(s) in RCA: 160] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2011] [Revised: 06/15/2012] [Accepted: 06/26/2012] [Indexed: 11/10/2022]
Abstract
Previous studies suggest physical activity improves cognition and lowers Alzheimer's disease (AD) risk. However, key AD pathogenic factors that are thought to be influenced by physical activity, particularly plasma amyloid-β (Aβ) and Aβ brain load, have yet to be thoroughly investigated. The objective of this study was to determine if plasma Aβ and amyloid brain deposition are associated with physical activity levels, and whether these associations differed between carriers and non-carriers of the apolipoprotein E (APOE) ε4 allele. Five-hundred and forty six cognitively intact participants (aged 60-95 years) from the Australian Imaging, Biomarkers and Lifestyle Study of Ageing (AIBL) were included in these analyses. Habitual physical activity levels were measured using the International Physical Activity Questionnaire (IPAQ). Serum insulin, glucose, cholesterol and plasma Aβ levels were measured in fasting blood samples. A subgroup (n=116) underwent (11)C-Pittsburgh compound B (PiB) positron emission tomography (PET) scanning to quantify brain amyloid load. Higher levels of physical activity were associated with higher high density lipoprotein (HDL) (P=0.037), and lower insulin (P<0.001), triglycerides (P=0.019) and Aβ1-42/1-40 ratio (P=0.001). After stratification of the cohort based on APOE ε4 allele carriage, it was evident that only non-carriers received the benefit of reduced plasma Aβ from physical activity. Conversely, lower levels of PiB SUVR (standardised uptake value ratio) were observed in higher exercising APOE ε4 carriers. Lower plasma Aβ1-42/1-40 and brain amyloid was observed in those reporting higher levels of physical activity, consistent with the hypothesis that physical activity may be involved in the modulation of pathogenic changes associated with AD.
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Affiliation(s)
- B M Brown
- Centre of Excellence for Alzheimer's Disease Research and Care, School of Medical Sciences, Edith Cowan University, Joondalup, WA, Australia
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MER5101, a novel Aβ1-15:DT conjugate vaccine, generates a robust anti-Aβ antibody response and attenuates Aβ pathology and cognitive deficits in APPswe/PS1ΔE9 transgenic mice. J Neurosci 2013; 33:7027-37. [PMID: 23595760 DOI: 10.1523/jneurosci.5924-12.2013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Active amyloid-β (Aβ) immunotherapy is under investigation to prevent or treat early Alzheimer's disease (AD). In 2002, a Phase II clinical trial (AN1792) was halted due to meningoencephalitis in ∼6% of the AD patients, possibly caused by a T-cell-mediated immunological response. Thus, generating a vaccine that safely generates high anti-Aβ antibody levels in the elderly is required. In this study, MER5101, a novel conjugate of Aβ1-15 peptide (a B-cell epitope fragment) conjugated to an immunogenic carrier protein, diphtheria toxoid (DT), and formulated in a nanoparticular emulsion-based adjuvant, was administered to 10-month-old APPswe/PS1ΔE9 transgenic (Tg) and wild-type (Wt) mice. High anti-Aβ antibody levels were observed in both vaccinated APPswe/PS1ΔE9 Tg and Wt mice. Antibody isotypes were mainly IgG1 and IgG2b, suggesting a Th2-biased response. Restimulation of splenocytes with the Aβ1-15:DT conjugate resulted in a strong proliferative response, whereas proliferation was absent after restimulation with Aβ1-15 or Aβ1-40/42 peptides, indicating a cellular immune response against DT while avoiding an Aβ-specific T-cell response. Moreover, significant reductions in cerebral Aβ plaque burden, accompanied by attenuated microglial activation and increased synaptic density, were observed in MER5101-vaccinated APPswe/PS1ΔE9 Tg mice compared with Tg adjuvant controls. Last, MER5101-immunized APPswe/PS1ΔE9 Tg mice showed improvement of cognitive deficits in both contextual fear conditioning and the Morris water maze. Our novel, highly immunogenic Aβ conjugate vaccine, MER5101, shows promise for improving Aβ vaccine safety and efficacy and therefore, may be useful for preventing and/or treating early AD.
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Namekawa Y, Baba H, Maeshima H, Nakano Y, Satomura E, Takebayashi N, Nomoto H, Suzuki T, Arai H. Heterogeneity of elderly depression: increased risk of Alzheimer's disease and Aβ protein metabolism. Prog Neuropsychopharmacol Biol Psychiatry 2013; 43:203-8. [PMID: 23276885 DOI: 10.1016/j.pnpbp.2012.12.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2012] [Revised: 12/07/2012] [Accepted: 12/19/2012] [Indexed: 12/17/2022]
Abstract
Epidemiological studies have proposed that depression may increase the risk for Alzheimer's disease (AD), even in patients with early-onset depression. Although metabolism of amyloid β protein (Aβ) in elderly depression received attention in terms of their correlation, there is a serious heterogeneity in elderly depression in terms of age at onset of depression. Moreover, it is unknown whether early-onset major depressive disorder (MDD) has a long-term effect on the involvement of Aβ metabolism and later development of AD. Thus, we evaluated serum Aβ40 and Aβ42 levels, the Aβ40/Aβ42 ratio in 89 elderly (≥60 years of age) inpatients with MDD and 81 age-matched healthy controls, and compared them among patients with early-onset (<60 years) and late-onset (≥60years) MDD and controls. The results showed that the serum Aβ40/Aβ42 ratio was significantly higher in patients with both early- and late-onset MDD than in controls (early-onset, p=0.010; late-onset, p=0.043), and it is of great interest that the serum Aβ40/Aβ42 ratio was negatively correlated with the age at MDD onset (R=-0.201, p=0.032). These results suggest that an earlier onset of MDD may have a more serious abnormality in Aβ metabolism, possibly explaining a biological mechanism underlying the link between depression and AD.
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Affiliation(s)
- Yuki Namekawa
- Juntendo University Mood Disorder Project (JUMP), Department of Psychiatry, Juntendo Koshigaya Hospital, Saitama, Japan
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Gabelle A, Richard F, Gutierrez LA, Schraen S, Delva F, Rouaud O, Buée L, Dartigues JF, Touchon J, Lambert JC, Berr C. Plasma amyloid-β levels and prognosis in incident dementia cases of the 3-City Study. J Alzheimers Dis 2013; 33:381-91. [PMID: 22976074 DOI: 10.3233/jad-2012-121147] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Studies of plasma amyloid-β (Aβ) levels as potential biomarkers for incident Alzheimer's disease (AD) have yielded contradictory results. We explored the associations between plasma Aβ(40), Aβ(42), and truncated Aβ levels, and prognosis of dementia in participants of the prospective 3-City Study. 120 aged individuals diagnosed with 2-year incident dementia were followed up for seven years. The associations between Aβ plasma levels and baseline cognitive score, cognitive decline, and death were examined. A higher level of baseline plasma Aβ was associated with worse cognitive status two years prior to incident dementia diagnosis. In incident AD patients, the association was only significant for Aβ(40) and Aβ(n-42). In the fast cognitive decliners group, especially in AD cases, a higher level of 5 pg/ml of baseline Aβ(42), Aβ(n-42), Aβ(n-42)/Aβ(n-40), and Aβ(42)/Aβ(40) ratios were associated with a lower risk of fast cognitive decline based on the Isaacs Set Test score. There was no association between peptide levels and mortality in demented subjects. When assayed at prodromal stage, plasma Aβ levels may be potentially useful markers of fast cognitive decline in individuals who subsequently become demented.
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Affiliation(s)
- Audrey Gabelle
- Department of Neurology, Centre Mémoire Ressources Recherche Languedoc-Roussillon, CHRU Gui de Chauliac Hospital, Montpellier, France.
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Hedden T, Oh H, Younger AP, Patel TA. Meta-analysis of amyloid-cognition relations in cognitively normal older adults. Neurology 2013; 80:1341-8. [PMID: 23547267 DOI: 10.1212/wnl.0b013e31828ab35d] [Citation(s) in RCA: 265] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVE We conducted a meta-analysis of relationships between amyloid burden and cognition in cognitively normal, older adult humans. METHODS Methods of assessing amyloid burden included were CSF or plasma assays, histopathology, and PET ligands. Cognitive domains examined were episodic memory, executive function, working memory, processing speed, visuospatial function, semantic memory, and global cognition. Sixty-four studies representing 7,140 subjects met selection criteria, with 3,495 subjects from 34 studies representing independent cohorts. Weighted effect sizes were obtained for each study. Primary analyses were conducted limiting to independent cohort studies using only the most common assessment method (Pittsburgh compound B). Exploratory analyses included all assessment methods. RESULTS Episodic memory (r = 0.12) had a significant relationship to amyloid burden. Executive function and global cognition did not have significant relationships to amyloid in the primary analysis of Pittsburgh compound B (r = 0.05 and r = 0.08, respectively), but did when including all assessment methods (r = 0.08 and r = 0.09, respectively). The domains of working memory, processing speed, visuospatial function, and semantic memory did not have significant relationships to amyloid. Differences in the method of amyloid assessment, study design (longitudinal vs cross-sectional), or inclusion of control variables (age, etc.) had little influence. CONCLUSIONS Based on this meta-analytic survey of the literature, increased amyloid burden has small but nontrivial associations with specific domains of cognitive performance in individuals who are currently cognitively normal. These associations may be useful for identifying preclinical Alzheimer disease or developing clinical outcome measures.
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Affiliation(s)
- Trey Hedden
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, CA, USA.
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Tan WW, Heckman MG, Vishnu P, Crook JE, Younkin LH, Covil EG, Ferman TJ, Graff-Radford NR, Younkin SG, Smallridge RC, Wehle MJ, Buskirk SJ. Effect of leuprolide on serum amyloid-β peptide levels and memory in patients with prostate cancer with biochemical recurrence. Urology 2013; 81:150-4. [PMID: 23273081 DOI: 10.1016/j.urology.2012.08.066] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2012] [Revised: 07/30/2012] [Accepted: 08/02/2012] [Indexed: 10/27/2022]
Abstract
OBJECTIVE To investigate whether prostate cancer patients receiving leuprolide demonstrated objective cognitive decline accompanied by a change in plasma levels of amyloid-β. METHODS Between November 19, 2003, and July 21, 2008, we prospectively enrolled 50 patients with biochemical recurrence of prostate cancer and measured plasma amyloid-β peptide 40 and amyloid-β peptide 42 levels with sandwich enzyme-linked immunosorbent assay at baseline before the first leuprolide injection and at 2, 4, and 12 months. The Mini-Mental State Examination was used to assess 49 patients at baseline and at subsequent visits, and 24 were also assessed by the California Verbal Learning Test-Short Form. RESULTS Patients were a median age of 71 years (range, 59-89 years). Compared with baseline levels, plasma amyloid-β peptide 40 levels were increased at 2 months (P=.04) and 4 months (P=.02). Age was correlated with plasma amyloid-β peptide 40 levels (P=.003) and likely accounted for this relationship. Plasma amyloid-β peptide 42 and performance on cognitive tasks did not differ from baseline, but memory measures improved slightly after baseline, most likely due to a practice effect. CONCLUSION Leuprolide therapy was not associated with a decline in cognition or memory function or with elevated plasma amyloid short-term. Larger studies are needed to confirm these findings.
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Affiliation(s)
- Winston W Tan
- Division of Hematology, Oncology, Cancer Center, GU Oncology, Department of Neurology, Mayo Clinic, Jacksonville, FL 32224, USA.
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50
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Rembach A, Faux NG, Watt AD, Pertile KK, Rumble RL, Trounson BO, Fowler CJ, Roberts BR, Perez KA, Li QX, Laws SM, Taddei K, Rainey-Smith S, Robertson JS, Vandijck M, Vanderstichele H, Barnham KJ, Ellis KA, Szoeke C, Macaulay L, Rowe CC, Villemagne VL, Ames D, Martins RN, Bush AI, Masters CL. Changes in plasma amyloid beta in a longitudinal study of aging and Alzheimer's disease. Alzheimers Dement 2013; 10:53-61. [PMID: 23491263 DOI: 10.1016/j.jalz.2012.12.006] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Revised: 10/19/2012] [Accepted: 12/08/2012] [Indexed: 12/28/2022]
Abstract
BACKGROUND A practical biomarker is required to facilitate the preclinical diagnosis of Alzheimer's disease (AD). METHODS Plasma amyloid beta (Aβ)1-40, Aβ1-42, Aβn-40, and Aβn-42 peptides were measured at baseline and after 18 months in 771 participants from the Australian Imaging Biomarkers and Lifestyle (AIBL) study of aging. Aβ peptide levels were compared with clinical pathology, neuroimaging and neuropsychological measurements. RESULTS Although inflammatory and renal function covariates influenced plasma Aβ levels significantly, a decrease in Aβ1-42/Aβ1-40 was observed in patients with AD, and was also inversely correlated with neocortical amyloid burden. During the 18 months, plasma Aβ1-42 decreased in subjects with mild cognitive impairment (MCI) and in those transitioning from healthy to MCI. CONCLUSION Our findings are consistent with a number of published plasma Aβ studies and, although the prognostic value of individual measures in any given subject is limited, the diagnostic contribution of plasma Aβ may demonstrate utility when combined with a panel of peripheral biomarkers.
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Affiliation(s)
- Alan Rembach
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia.
| | - Noel G Faux
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Andrew D Watt
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Kelly K Pertile
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Rebecca L Rumble
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Brett O Trounson
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Christopher J Fowler
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Blaine R Roberts
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Keyla A Perez
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Qiao-Xin Li
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Simon M Laws
- Sir James McCusker Alzheimer's Disease Research Unit (Hollywood Private Hospital), Perth, Western Australia, Australia; Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup. Western Australia, Australia
| | - Kevin Taddei
- Sir James McCusker Alzheimer's Disease Research Unit (Hollywood Private Hospital), Perth, Western Australia, Australia; Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup. Western Australia, Australia
| | - Stephanie Rainey-Smith
- Sir James McCusker Alzheimer's Disease Research Unit (Hollywood Private Hospital), Perth, Western Australia, Australia; Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup. Western Australia, Australia
| | - Joanne S Robertson
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Manu Vandijck
- Department of Diagnostic Development, Innogenetics NV, Ghent, Belgium
| | - Hugo Vanderstichele
- Department of Diagnostic Development, Innogenetics NV, Ghent, Belgium; Biomarkable, Gent, Belgium
| | - Kevin J Barnham
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Kathryn A Ellis
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia; Department of Psychiatry, St George's Hospital, University of Melbourne, Victoria, Australia; National Ageing Research Institute, Parkville, Victoria, Australia
| | - Cassandra Szoeke
- Department of Psychiatry, St George's Hospital, University of Melbourne, Victoria, Australia; National Ageing Research Institute, Parkville, Victoria, Australia
| | - Lance Macaulay
- CSIRO Molecular and Health Technologies, Parkville, Victoria, Australia
| | - Christopher C Rowe
- Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, Victoria, Australia
| | - Victor L Villemagne
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia; Department of Nuclear Medicine and Centre for PET, Austin Health, Heidelberg, Victoria, Australia
| | - David Ames
- National Ageing Research Institute, Parkville, Victoria, Australia
| | - Ralph N Martins
- Sir James McCusker Alzheimer's Disease Research Unit (Hollywood Private Hospital), Perth, Western Australia, Australia; Centre of Excellence for Alzheimer's Disease Research & Care, School of Medical Sciences, Edith Cowan University, Joondalup. Western Australia, Australia
| | - Ashley I Bush
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
| | - Colin L Masters
- The Mental Health Research Institute, The University of Melbourne, Victoria, Australia
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