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Swinford CG, Risacher SL, Vosmeier A, Deardorff R, Chumin EJ, Dzemidzic M, Wu YC, Gao S, McDonald BC, Yoder KK, Unverzagt FW, Wang S, Farlow MR, Brosch JR, Clark DG, Apostolova LG, Sims J, Wang DJ, Saykin AJ. Amyloid and tau pathology are associated with cerebral blood flow in a mixed sample of nondemented older adults with and without vascular risk factors for Alzheimer's disease. Neurobiol Aging 2023; 130:103-113. [PMID: 37499587 PMCID: PMC10529454 DOI: 10.1016/j.neurobiolaging.2023.06.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 05/30/2023] [Accepted: 06/21/2023] [Indexed: 07/29/2023]
Abstract
Identification of biomarkers for the early stages of Alzheimer's disease (AD) is an imperative step in developing effective treatments. Cerebral blood flow (CBF) is a potential early biomarker for AD; generally, older adults with AD have decreased CBF compared to normally aging peers. CBF deviates as the disease process and symptoms progress. However, further characterization of the relationships between CBF and AD risk factors and pathologies is still needed. We assessed the relationships between CBF quantified by arterial spin-labeled magnetic resonance imaging, hypertension, APOEε4, and tau and amyloid positron emission tomography in 77 older adults: cognitively normal, subjective cognitive decline, and mild cognitive impairment. Tau and amyloid aggregation were related to altered CBF, and some of these relationships were dependent on hypertension or APOEε4 status. Our findings suggest a complex relationship between risk factors, AD pathologies, and CBF that warrants future studies of CBF as a potential early biomarker for AD.
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Affiliation(s)
- Cecily G Swinford
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA
| | - Shannon L Risacher
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA
| | - Aaron Vosmeier
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA
| | - Rachael Deardorff
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA
| | - Evgeny J Chumin
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Indiana University Network Science Institute, Bloomington, IN, USA; Department of Psychological and Brain Sciences, Indiana University, Bloomington, IN, USA
| | - Mario Dzemidzic
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Yu-Chien Wu
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA
| | - Sujuan Gao
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Biostatistics and Health Data Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Brenna C McDonald
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Karmen K Yoder
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA
| | - Frederick W Unverzagt
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sophia Wang
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Psychiatry, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Martin R Farlow
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Jared R Brosch
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - David G Clark
- Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Liana G Apostolova
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana University Network Science Institute, Bloomington, IN, USA
| | - Justin Sims
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Danny J Wang
- Stevens Neuroimaging and Informatics Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Andrew J Saykin
- Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer's Disease Research Center, Indianapolis, IN, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana University Network Science Institute, Bloomington, IN, USA.
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Kok FK, van Leerdam SL, de Lange ECM. Potential Mechanisms Underlying Resistance to Dementia in Non-Demented Individuals with Alzheimer's Disease Neuropathology. J Alzheimers Dis 2022; 87:51-81. [PMID: 35275527 PMCID: PMC9198800 DOI: 10.3233/jad-210607] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Alzheimer’s disease (AD) is the most common form of dementia and typically characterized by the accumulation of amyloid-β plaques and tau tangles. Intriguingly, there also exists a group of elderly which do not develop dementia during their life, despite the AD neuropathology, the so-called non-demented individuals with AD neuropathology (NDAN). In this review, we provide extensive background on AD pathology and normal aging and discuss potential mechanisms that enable these NDAN individuals to remain cognitively intact. Studies presented in this review show that NDAN subjects are generally higher educated and have a larger cognitive reserve. Furthermore, enhanced neural hypertrophy could compensate for hippocampal and cingulate neural atrophy in NDAN individuals. On a cellular level, these individuals show increased levels of neural stem cells and ‘von Economo neurons’. Furthermore, in NDAN brains, binding of Aβ oligomers to synapses is prevented, resulting in decreased glial activation and reduced neuroinflammation. Overall, the evidence stated here strengthens the idea that some individuals are more resistant to AD pathology, or at least show an elongation of the asymptomatic state of the disease compared to others. Insights into the mechanisms underlying this resistance could provide new insight in understanding normal aging and AD itself. Further research should focus on factors and mechanisms that govern the NDAN cognitive resilience in order to find clues on novel biomarkers, targets, and better treatments of AD.
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Affiliation(s)
- Frédérique K Kok
- Predictive Pharmacology, Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre of Drug Research, Leiden University, Leiden, The Netherlands
| | - Suzanne L van Leerdam
- Predictive Pharmacology, Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre of Drug Research, Leiden University, Leiden, The Netherlands
| | - Elizabeth C M de Lange
- Predictive Pharmacology, Division of Systems Biomedicine and Pharmacology, Leiden Academic Centre of Drug Research, Leiden University, Leiden, The Netherlands
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Abstract
Intracellular accumulation of abnormally phosphorylated tau in different types of neurons is a pathological characteristic of Alzheimer's disease (AD). While tau modification and associated neuronal loss and hypometabolism start in the entorhinal cortex (EC) in early AD patients, the mechanism by which mutant P301L hTau leads to dementia is not fully elucidated. Here, we studied the effects of P301L hTau transduction in the medial EC (MEC) of mice on tau phosphorylation and accumulation, and cognitive deficit. We found that the exogenous mutant tau protein was restricted in MEC without spreading to other brain regions at one month after transduction. Interestingly, expression of the mutant tau in MEC induces endogenous tau hyperphosphorylation and accumulation in hippocampus and cortex, and inhibits neuronal activity with attenuated PP-DG synapse plasticity, leading to hippocampus-dependent memory deficit with intact olfactory function. These findings suggest a novel neuropathological mechanism of early AD, which is initiated by tau accumulation in MEC, and demonstrate a tau pathological model of early stage AD.
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Xiao MF, Xu D, Craig MT, Pelkey KA, Chien CC, Shi Y, Zhang J, Resnick S, Pletnikova O, Salmon D, Brewer J, Edland S, Wegiel J, Tycko B, Savonenko A, Reeves RH, Troncoso JC, McBain CJ, Galasko D, Worley PF. NPTX2 and cognitive dysfunction in Alzheimer's Disease. eLife 2017; 6. [PMID: 28440221 PMCID: PMC5404919 DOI: 10.7554/elife.23798] [Citation(s) in RCA: 132] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 03/15/2017] [Indexed: 12/14/2022] Open
Abstract
Memory loss in Alzheimer’s disease (AD) is attributed to pervasive weakening and loss of synapses. Here, we present findings supporting a special role for excitatory synapses connecting pyramidal neurons of the hippocampus and cortex with fast-spiking parvalbumin (PV) interneurons that control network excitability and rhythmicity. Excitatory synapses on PV interneurons are dependent on the AMPA receptor subunit GluA4, which is regulated by presynaptic expression of the synaptogenic immediate early gene NPTX2 by pyramidal neurons. In a mouse model of AD amyloidosis, Nptx2-/- results in reduced GluA4 expression, disrupted rhythmicity, and increased pyramidal neuron excitability. Postmortem human AD cortex shows profound reductions of NPTX2 and coordinate reductions of GluA4. NPTX2 in human CSF is reduced in subjects with AD and shows robust correlations with cognitive performance and hippocampal volume. These findings implicate failure of adaptive control of pyramidal neuron-PV circuits as a pathophysiological mechanism contributing to cognitive failure in AD. DOI:http://dx.doi.org/10.7554/eLife.23798.001
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Affiliation(s)
- Mei-Fang Xiao
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States.,Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Desheng Xu
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Michael T Craig
- Program in Developmental Neurobiology, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, Bethesda, United States
| | - Kenneth A Pelkey
- Program in Developmental Neurobiology, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, Bethesda, United States
| | - Chun-Che Chien
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Yang Shi
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Juhong Zhang
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Susan Resnick
- Laboratory of Behavioral Neuroscience, National Institute on Aging, Intramural Research Program, Baltimore, United States
| | - Olga Pletnikova
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - David Salmon
- Department of Neurosciences, University of California San Diego Medical Center, San Diego, United States.,Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego Medical Center, San Diego, United States
| | - James Brewer
- Department of Neurosciences, University of California San Diego Medical Center, San Diego, United States.,Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego Medical Center, San Diego, United States
| | - Steven Edland
- Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego Medical Center, San Diego, United States.,Division of Biostatistics and Bioinformatics, University of California San Diego, San Diego, United States
| | - Jerzy Wegiel
- Institute for Basic Research, New York City, United States
| | - Benjamin Tycko
- Taub Institute for Research on Alzheimer's disease and the Aging Brain, Columbia University, New York City, United States
| | - Alena Savonenko
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Roger H Reeves
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, United States.,Institute for Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Juan C Troncoso
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, United States
| | - Chris J McBain
- Program in Developmental Neurobiology, Eunice Kennedy-Shriver National Institute of Child Health and Human Development, Bethesda, United States
| | - Douglas Galasko
- Department of Neurosciences, University of California San Diego Medical Center, San Diego, United States.,Shiley-Marcos Alzheimer's Disease Research Center, University of California San Diego Medical Center, San Diego, United States
| | - Paul F Worley
- Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, United States.,Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, United States
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Son SJ, Kim J, Seo J, Lee JM, Park H. Connectivity analysis of normal and mild cognitive impairment patients based on FDG and PiB-PET images. Neurosci Res 2015; 98:50-8. [DOI: 10.1016/j.neures.2015.04.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2014] [Revised: 04/02/2015] [Accepted: 04/08/2015] [Indexed: 01/18/2023]
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Hohman TJ, Koran MEI, Thornton-Wells TA. Genetic modification of the relationship between phosphorylated tau and neurodegeneration. Alzheimers Dement 2014; 10:637-645.e1. [PMID: 24656848 PMCID: PMC4169762 DOI: 10.1016/j.jalz.2013.12.022] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2013] [Revised: 12/04/2013] [Accepted: 12/09/2013] [Indexed: 01/18/2023]
Abstract
BACKGROUND A subset of individuals present at autopsy with the pathologic features of Alzheimer's disease having never manifest the clinical symptoms. We sought to identify genetic factors that modify the relationship between phosphorylated tau (PTau) and dilation of the lateral inferior ventricles. METHODS We used data from 700 subjects enrolled in the Alzheimer's Disease Neuroimaging Initiative (ADNI). A genome-wide association study approach was used to identify PTau × single nucleotide polymorphism (SNP) interactions. Variance explained by these interactions was quantified using hierarchical linear regression. RESULTS Five SNP × PTau interactions passed a Bonferroni correction, one of which (rs4728029, POT1, 2.6% of variance) was consistent across ADNI-1 and ADNI-2/GO subjects. This interaction also showed a trend-level association with memory performance and levels of interleukin-6 receptor. CONCLUSIONS Our results suggest that rs4728029 modifies the relationship between PTau and both ventricular dilation and cognition, perhaps through an altered neuroinflammatory response.
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Affiliation(s)
- Timothy J Hohman
- The Center for Human Genetics Research, Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA.
| | - Mary Ellen I Koran
- The Center for Human Genetics Research, Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Tricia A Thornton-Wells
- The Center for Human Genetics Research, Department of Molecular Physiology & Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
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Mild cognitive impairment and asymptomatic Alzheimer disease subjects: equivalent β-amyloid and tau loads with divergent cognitive outcomes. J Neuropathol Exp Neurol 2014; 73:295-304. [PMID: 24607960 DOI: 10.1097/nen.0000000000000052] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Older adults with intact cognition before death and substantial Alzheimer disease (AD) lesions at autopsy have been termed "asymptomatic AD subjects" (ASYMAD). We previously reported hypertrophy of neuronal cell bodies, nuclei, and nucleoli in the CA1 of the hippocampus (CA1), anterior cingulate gyrus, posterior cingulate gyrus, and primary visual cortex of ASYMAD versus age-matched Control and mild cognitive impairment (MCI) subjects. However, it was unclear whether the neuronal hypertrophy could be attributed to differences in the severity of AD pathology. Here, we performed quantitative analyses of the severity of β-amyloid (Aβ) and phosphorylated tau (tau) loads in the brains of ASYMAD, Control, MCI, and AD subjects (n = 15 per group) from the Baltimore Longitudinal Study of Aging. Tissue sections from CA1, anterior cingulate gyrus, posterior cingulate gyrus, and primary visual cortex were immunostained for Aβ and tau; the respective loads were assessed using unbiased stereology by measuring the fractional areas of immunoreactivity for each protein in each region. The ASYMAD and MCI groups did not differ in Aβ and tau loads. These data confirm that ASYMAD and MCI subjects have comparable loads of insoluble Aβ and tau in regions vulnerable to AD pathology despite divergent cognitive outcomes. These findings imply that cognitive impairment in AD may be caused or modulated by factors other than insoluble forms of Aβ and tau.
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8
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Abstract
Evidence is growing that vascular risk factors (VRFs) for Alzheimer's disease (AD) affect cerebral hemodynamics to launch a cascade of cellular and molecular changes that initiate cognitive deficits and eventual progression of AD. Neuroimaging studies have reported VRFs for AD to be accurate predictors of cognitive decline and dementia. In regions that participate in higher cognitive function, middle temporal, posterior cingulate, inferior parietal and precuneus regions, and neuroimaging studies indicate an association involving VRFs, cerebral hypoperfusion, and cognitive decline in elderly individuals who develop AD. The VRF can be present in cognitively intact individuals for decades before mild cognitive deficits or neuropathological signs are manifested. In that sense, they may be "ticking time bombs" before cognitive function is demolished. Preventive intervention of modifiable VRF may delay or block progression of AD. Intervention could target cerebral blood flow (CBF), since most VRFs act to lower CBF in aging individuals by promoting cerebrovascular dysfunction.
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Li X, Li TQ, Andreasen N, Wiberg MK, Westman E, Wahlund LO. Ratio of Aβ42/P-tau181p in CSF is associated with aberrant default mode network in AD. Sci Rep 2013; 3:1339. [PMID: 23439248 PMCID: PMC3581831 DOI: 10.1038/srep01339] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Accepted: 02/07/2013] [Indexed: 01/18/2023] Open
Abstract
The default mode network (DMN) is particularly relevant to Alzheimer's disease (AD) since its structures are vulnerable to deposition of amyloid. Decreased levels of β-amyloid1-42 (Aβ42) and increased total tau protein (T-tau) and tau phosphorylated at position threonine 181 (P-tau181p) in cerebrospinal fluid (CSF) have been established as valid biomarkers for the diagnosis and prognosis of AD. However, the relationship between CSF biomarkers and change in the DMN is still unknown. In this study we investigated the correlation between the functional connectivity within the DMN and the ratio of Aβ42/P-tau181p in the CSF. We found that the ratio of Aβ42/P-tau181p was moderately positively correlated with the functional connectivity within the DMN in the left precuneus/cuneus. This finding implicates that the brain functional connectivity within DMN is affected by pathological changes at early stage in AD. This may provide a better understanding of AD pathology progression and improve AD diagnosis.
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Affiliation(s)
- Xiaozhen Li
- Department of Neurobiology, Care Sciences and Society, Karolinska Institutet, Stockholm, Sweden
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Abstract
Deposition of amyloid-β (Aβ) in cerebral arteries, known as cerebral amyloid angiopathy (CAA), occurs both in the setting of Alzheimer's disease and independent of it, and can cause cerebrovascular insufficiency and cognitive deficits. The mechanisms leading to CAA have not been established, and no therapeutic targets have been identified. We investigated the role of CD36, an innate immunity receptor involved in Aβ trafficking, in the neurovascular dysfunction, cognitive deficits, and amyloid accumulation that occurs in mice expressing the Swedish mutation of the amyloid precursor protein (Tg2576). We found that Tg2576 mice lacking CD36 have a selective reduction in Aβ1-40 and CAA. This reduced vascular amyloid deposition was associated with preservation of the Aβ vascular clearance receptor LRP-1, and protection from the deleterious effects of Aβ on cerebral arterioles. These beneficial vascular effects were reflected by marked improvements in neurovascular regulation and cognitive performance. Our data suggest that CD36 promotes vascular amyloid deposition and the resulting cerebrovascular damage, leading to neurovascular dysfunction and cognitive deficits. These findings identify a previously unrecognized role of CD36 in the mechanisms of vascular amyloid deposition, and suggest that this scavenger receptor is a putative therapeutic target for CAA and related conditions.
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