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Madrid LI, Hafey K, Bandhavkar S, Bodea GO, Jimenez-Martin J, Milne M, Walker TL, Faulkner GJ, Coulson EJ, Jhaveri DJ. Stimulation of the muscarinic receptor M4 regulates neural precursor cell proliferation and promotes adult hippocampal neurogenesis. Development 2024; 151:dev201835. [PMID: 38063486 PMCID: PMC10820734 DOI: 10.1242/dev.201835] [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: 04/03/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024]
Abstract
Cholinergic signaling plays a crucial role in the regulation of adult hippocampal neurogenesis; however, the mechanisms by which acetylcholine mediates neurogenic effects are not completely understood. Here, we report the expression of muscarinic acetylcholine receptor subtype M4 (M4 mAChR) on a subpopulation of neural precursor cells (NPCs) in the adult mouse hippocampus, and demonstrate that its pharmacological stimulation promotes their proliferation, thereby enhancing the production of new neurons in vivo. Using a targeted ablation approach, we also show that medial septum (MS) and the diagonal band of Broca (DBB) cholinergic neurons support both the survival and morphological maturation of adult-born neurons in the mouse hippocampus. Although the systemic administration of an M4-selective allosteric potentiator fails to fully rescue the MS/DBB cholinergic lesion-induced decrease in hippocampal neurogenesis, it further exacerbates the impairment in the morphological maturation of adult-born neurons. Collectively, these findings reveal stage-specific roles of M4 mAChRs in regulating adult hippocampal neurogenesis, uncoupling their positive role in enhancing the production of new neurons from the M4-induced inhibition of their morphological maturation, at least in the context of cholinergic signaling dysfunction.
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Affiliation(s)
- Lidia I. Madrid
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
| | - Katelyn Hafey
- Mater Research Institute - The University of Queensland, Translational Research Institute, Brisbane QLD 4102, Queensland, Australia
| | - Saurabh Bandhavkar
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
- Mater Research Institute - The University of Queensland, Translational Research Institute, Brisbane QLD 4102, Queensland, Australia
| | - Gabriela O. Bodea
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
- Mater Research Institute - The University of Queensland, Translational Research Institute, Brisbane QLD 4102, Queensland, Australia
| | - Javier Jimenez-Martin
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
| | - Michael Milne
- School of Biomedical Sciences, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
| | - Tara L. Walker
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
| | - Geoffrey J. Faulkner
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
- Mater Research Institute - The University of Queensland, Translational Research Institute, Brisbane QLD 4102, Queensland, Australia
| | - Elizabeth J. Coulson
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
- School of Biomedical Sciences, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
| | - Dhanisha J. Jhaveri
- Queensland Brain Institute, The University of Queensland, Brisbane QLD 4072, Queensland, Australia
- Mater Research Institute - The University of Queensland, Translational Research Institute, Brisbane QLD 4102, Queensland, Australia
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Moon HS, Mahzarnia A, Stout J, Anderson RJ, Badea CT, Badea A. Feature attention graph neural network for estimating brain age and identifying important neural connections in mouse models of genetic risk for Alzheimer's disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.12.13.571574. [PMID: 38168445 PMCID: PMC10760088 DOI: 10.1101/2023.12.13.571574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2024]
Abstract
Alzheimer's disease (AD) remains one of the most extensively researched neurodegenerative disorders due to its widespread prevalence and complex risk factors. Age is a crucial risk factor for AD, which can be estimated by the disparity between physiological age and estimated brain age. To model AD risk more effectively, integrating biological, genetic, and cognitive markers is essential. Here, we utilized mouse models expressing the major APOE human alleles and human nitric oxide synthase 2 to replicate genetic risk for AD and a humanized innate immune response. We estimated brain age employing a multivariate dataset that includes brain connectomes, APOE genotype, subject traits such as age and sex, and behavioral data. Our methodology used Feature Attention Graph Neural Networks (FAGNN) for integrating different data types. Behavioral data were processed with a 2D Convolutional Neural Network (CNN), subject traits with a 1D CNN, brain connectomes through a Graph Neural Network using quadrant attention module. The model yielded a mean absolute error for age prediction of 31.85 days, with a root mean squared error of 41.84 days, outperforming other, reduced models. In addition, FAGNN identified key brain connections involved in the aging process. The highest weights were assigned to the connections between cingulum and corpus callosum, striatum, hippocampus, thalamus, hypothalamus, cerebellum, and piriform cortex. Our study demonstrates the feasibility of predicting brain age in models of aging and genetic risk for AD. To verify the validity of our findings, we compared Fractional Anisotropy (FA) along the tracts of regions with the highest connectivity, the Return-to-Origin Probability (RTOP), Return-to-Plane Probability (RTPP), and Return-to-Axis Probability (RTAP), which showed significant differences between young, middle-aged, and old age groups. Younger mice exhibited higher FA, RTOP, RTAP, and RTPP compared to older groups in the selected connections, suggesting that degradation of white matter tracts plays a critical role in aging and for FAGNN's selections. Our analysis suggests a potential neuroprotective role of APOE2, relative to APOE3 and APOE4, where APOE2 appears to mitigate age-related changes. Our findings highlighted a complex interplay of genetics and brain aging in the context of AD risk modeling.
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Affiliation(s)
- Hae Sol Moon
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Quantitative Imaging and Analysis Laboratory, Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Ali Mahzarnia
- Quantitative Imaging and Analysis Laboratory, Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Jacques Stout
- Quantitative Imaging and Analysis Laboratory, Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Robert J Anderson
- Quantitative Imaging and Analysis Laboratory, Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Cristian T. Badea
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Quantitative Imaging and Analysis Laboratory, Department of Radiology, Duke University School of Medicine, Durham, NC, USA
| | - Alexandra Badea
- Department of Biomedical Engineering, Duke University, Durham, NC, USA
- Quantitative Imaging and Analysis Laboratory, Department of Radiology, Duke University School of Medicine, Durham, NC, USA
- Brain Imaging and Analysis Center, Duke University School of Medicine, Durham, NC, USA
- Department of Neurology, Duke University School of Medicine, Durham, NC, USA
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Gamage R, Rossetti I, Niedermayer G, Münch G, Buskila Y, Gyengesi E. Chronic neuroinflammation during aging leads to cholinergic neurodegeneration in the mouse medial septum. J Neuroinflammation 2023; 20:235. [PMID: 37833764 PMCID: PMC10576363 DOI: 10.1186/s12974-023-02897-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 09/14/2023] [Indexed: 10/15/2023] Open
Abstract
BACKGROUND Low-grade, chronic inflammation in the central nervous system characterized by glial reactivity is one of the major hallmarks for aging-related neurodegenerative diseases like Alzheimer's disease (AD). The basal forebrain cholinergic neurons (BFCN) provide the primary source of cholinergic innervation of the human cerebral cortex and may be differentially vulnerable in various neurodegenerative diseases. However, the impact of chronic neuroinflammation on the cholinergic function is still unclear. METHODS To gain further insight into age-related cholinergic decline, we investigated the cumulative effects of aging and chronic neuroinflammation on the structure and function of the septal cholinergic neurons in transgenic mice expressing interleukin-6 under the GFAP promoter (GFAP-IL6), which maintains a constant level of gliosis. Immunohistochemistry combined with unbiased stereology, single cell 3D morphology analysis and in vitro whole cell patch-clamp measurements were used to validate the structural and functional changes of BFCN and their microglial environment in the medial septum. RESULTS Stereological estimation of MS microglia number displayed significant increase across all three age groups, while a significant decrease in cholinergic cell number in the adult and aged groups in GFAP-IL6 mice compared to control. Moreover, we observed age-dependent alterations in the electrophysiological properties of cholinergic neurons and an increased excitability profile in the adult GFAP-IL6 group due to chronic neuroinflammation. These results complimented the significant decrease in hippocampal pyramidal spine density seen with aging and neuroinflammation. CONCLUSIONS We provide evidence of the significant impact of both aging and chronic glial activation on the cholinergic and microglial numbers and morphology in the MS, and alterations in the passive and active electrophysiological membrane properties of septal cholinergic neurons, resulting in cholinergic dysfunction, as seen in AD. Our results indicate that aging combined with gliosis is sufficient to cause cholinergic disruptions in the brain, as seen in dementias.
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Affiliation(s)
- Rashmi Gamage
- School of Medicine, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Ilaria Rossetti
- School of Medicine, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Garry Niedermayer
- School of Science, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Gerald Münch
- School of Medicine, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Yossi Buskila
- School of Medicine, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Erika Gyengesi
- School of Medicine, Western Sydney University, Penrith, NSW, 2751, Australia.
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Degiorgis L, Arefin TM, Ben-Hamida S, Noblet V, Antal C, Bienert T, Reisert M, von Elverfeldt D, Kieffer BL, Harsan LA. Translational Structural and Functional Signatures of Chronic Alcohol Effects in Mice. Biol Psychiatry 2022; 91:1039-1050. [PMID: 35654559 DOI: 10.1016/j.biopsych.2022.02.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 12/27/2022]
Abstract
BACKGROUND Alcohol acts as an addictive substance that may lead to alcohol use disorder. In humans, magnetic resonance imaging showed diverse structural and functional brain alterations associated with this complex pathology. Single magnetic resonance imaging modalities are used mostly but are insufficient to portray and understand the broad neuroadaptations to alcohol. Here, we combined structural and functional magnetic resonance imaging and connectome mapping in mice to establish brain-wide fingerprints of alcohol effects with translatable potential. METHODS Mice underwent a chronic intermittent alcohol drinking protocol for 6 weeks before being imaged under medetomidine anesthesia. We performed open-ended multivariate analysis of structural data and functional connectivity mapping on the same subjects. RESULTS Structural analysis showed alcohol effects for the prefrontal cortex/anterior insula, hippocampus, and somatosensory cortex. Integration with microglia histology revealed distinct alcohol signatures, suggestive of advanced (prefrontal cortex/anterior insula, somatosensory cortex) and early (hippocampus) inflammation. Functional analysis showed major alterations of insula, ventral tegmental area, and retrosplenial cortex connectivity, impacting communication patterns for salience (insula), reward (ventral tegmental area), and default mode (retrosplenial cortex) networks. The insula appeared as a most sensitive brain center across structural and functional analyses. CONCLUSIONS This study demonstrates alcohol effects in mice, which possibly underlie lower top-down control and impaired hedonic balance documented at the behavioral level, and aligns with neuroimaging findings in humans despite the potential limitation induced by medetomidine sedation. This study paves the way to identify further biomarkers and to probe neurobiological mechanisms of alcohol effects using genetic and pharmacological manipulations in mouse models of alcohol drinking and dependence.
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Affiliation(s)
- Laetitia Degiorgis
- Integrative Multimodal Imaging in Healthcare team, UMR 7357, Laboratory of Engineering, Informatics and Imaging (ICube); Department of Psychiatry, University of Strasbourg, Strasbourg, France
| | - Tanzil Mahmud Arefin
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University Freiburg, Freiburg, Germany; Bernard and Irene Schwartz Center for Biomedical Imaging, Department of Radiology, New York University Grossman School of Medicine, New York, New York
| | - Sami Ben-Hamida
- INSERM U1114, University Hospital of Strasbourg, Strasbourg, France; INSERM U1247, research group on alcohol and pharmacodependance (GRAP), University of Picardie Jules-Verne, Amiens, France
| | - Vincent Noblet
- Images, Learning, Geometry and Statistics team, UMR 7357, Laboratory of Engineering, Informatics and Imaging (ICube); Department of Psychiatry, University of Strasbourg, Strasbourg, France
| | - Cristina Antal
- Integrative Multimodal Imaging in Healthcare team, UMR 7357, Laboratory of Engineering, Informatics and Imaging (ICube); Department of Psychiatry, University of Strasbourg, Strasbourg, France; Faculty of Medicine, Histology Institute and Unité Fonctionnelle de Foetopathologie, University Hospital of Strasbourg, Strasbourg, France
| | - Thomas Bienert
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University Freiburg, Freiburg, Germany
| | - Marco Reisert
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University Freiburg, Freiburg, Germany
| | - Dominik von Elverfeldt
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University Freiburg, Freiburg, Germany
| | | | - Laura-Adela Harsan
- Integrative Multimodal Imaging in Healthcare team, UMR 7357, Laboratory of Engineering, Informatics and Imaging (ICube); Department of Psychiatry, University of Strasbourg, Strasbourg, France; Department of Biophysics and Nuclear Medicine, University Hospital of Strasbourg, Strasbourg, France.
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Zhou XA, Ngiam G, Qian L, Sankorrakul K, Coulson EJ, Chuang KH. The basal forebrain volume reduction detected by MRI does not necessarily link with the cholinergic neuronal loss in the Alzheimer's Disease mouse model. Neurobiol Aging 2022; 117:24-32. [DOI: 10.1016/j.neurobiolaging.2022.03.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2021] [Revised: 03/30/2022] [Accepted: 03/30/2022] [Indexed: 11/27/2022]
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Beaumont J, Gambarota G, Prior M, Fripp J, Reid LB. Avoiding data loss: Synthetic MRIs generated from diffusion imaging can replace corrupted structural acquisitions for freesurfer-seeded tractography. PLoS One 2022; 17:e0247343. [PMID: 35180211 PMCID: PMC8856573 DOI: 10.1371/journal.pone.0247343] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 11/30/2021] [Indexed: 11/18/2022] Open
Abstract
Magnetic Resonance Imaging (MRI) motion artefacts frequently complicate structural and diffusion MRI analyses. While diffusion imaging is easily ‘scrubbed’ of motion affected volumes, the same is not true for T1w or T2w ‘structural’ images. Structural images are critical to most diffusion-imaging pipelines thus their corruption can lead to disproportionate data loss. To enable diffusion-image processing when structural images are missing or have been corrupted, we propose a means by which synthetic structural images can be generated from diffusion MRI. This technique combines multi-tissue constrained spherical deconvolution, which is central to many existing diffusion analyses, with the Bloch equations that allow simulation of MRI intensities for given scanner parameters and magnetic resonance (MR) tissue properties. We applied this technique to 32 scans, including those acquired on different scanners, with different protocols and with pathology present. The resulting synthetic T1w and T2w images were visually convincing and exhibited similar tissue contrast to acquired structural images. These were also of sufficient quality to drive a Freesurfer-based tractographic analysis. In this analysis, probabilistic tractography connecting the thalamus to the primary sensorimotor cortex was delineated with Freesurfer, using either real or synthetic structural images. Tractography for real and synthetic conditions was largely identical in terms of both voxels encountered (Dice 0.88–0.95) and mean fractional anisotropy (intrasubject absolute difference 0.00–0.02). We provide executables for the proposed technique in the hope that these may aid the community in analysing datasets where structural image corruption is common, such as studies of children or cognitively impaired persons.
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Affiliation(s)
- Jeremy Beaumont
- The Australian e-Health Research Centre, CSIRO, Queensland, Australia
- Univ Rennes, INSERM, LTSI-UMR1099, Rennes, France
- * E-mail:
| | | | - Marita Prior
- Department of Medical Imaging, Royal Brisbane and Women’s Hospital, Herston, Queensland, Australia
| | - Jurgen Fripp
- The Australian e-Health Research Centre, CSIRO, Queensland, Australia
| | - Lee B. Reid
- The Australian e-Health Research Centre, CSIRO, Queensland, Australia
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Chu WT, Wang WE, Zaborszky L, Golde TE, DeKosky S, Duara R, Loewenstein DA, Adjouadi M, Coombes SA, Vaillancourt DE. Association of Cognitive Impairment With Free Water in the Nucleus Basalis of Meynert and Locus Coeruleus to Transentorhinal Cortex Tract. Neurology 2022; 98:e700-e710. [PMID: 34906980 PMCID: PMC8865892 DOI: 10.1212/wnl.0000000000013206] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 11/30/2021] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND AND OBJECTIVES The goal of this work was to determine the relationship between diffusion microstructure and early changes in Alzheimer disease (AD) severity as assessed by clinical diagnosis, cognitive performance, dementia severity, and plasma concentrations of neurofilament light chain. METHODS Diffusion MRI scans were collected on cognitively normal participants (CN) and patients with early mild cognitive impairment (EMCI), late mild cognitive impairment, and AD. Free water (FW) and FW-corrected fractional anisotropy were calculated in the locus coeruleus to transentorhinal cortex tract, 4 magnocellular regions of the basal forebrain (e.g., nucleus basalis of Meynert), entorhinal cortex, and hippocampus. All patients underwent a battery of cognitive assessments; neurofilament light chain levels were measured in plasma samples. RESULTS FW was significantly higher in patients with EMCI compared to CN in the locus coeruleus to transentorhinal cortex tract, nucleus basalis of Meynert, and hippocampus (mean Cohen d = 0.54; p fdr < 0.05). FW was significantly higher in those with AD compared to CN in all the examined regions (mean Cohen d = 1.41; p fdr < 0.01). In addition, FW in the hippocampus, entorhinal cortex, nucleus basalis of Meynert, and locus coeruleus to transentorhinal cortex tract positively correlated with all 5 cognitive impairment metrics and neurofilament light chain levels (mean r 2 = 0.10; p fdr < 0.05). DISCUSSION These results show that higher FW is associated with greater clinical diagnosis severity, cognitive impairment, and neurofilament light chain. They also suggest that FW elevation occurs in the locus coeruleus to transentorhinal cortex tract, nucleus basalis of Meynert, and hippocampus in the transition from CN to EMCI, while other basal forebrain regions and the entorhinal cortex are not affected until a later stage of AD. FW is a clinically relevant and noninvasive early marker of structural changes related to cognitive impairment.
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Affiliation(s)
- Winston Thomas Chu
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Wei-En Wang
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Laszlo Zaborszky
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Todd Eliot Golde
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Steven DeKosky
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Ranjan Duara
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - David A Loewenstein
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Malek Adjouadi
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - Stephen A Coombes
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami
| | - David E Vaillancourt
- From the J. Crayton Pruitt Family Department of Biomedical Engineering (W.T.C., D.E.V.), Department of Applied Physiology and Kinesiology (W.T.C., W.-e.W., S.A.C., D.E.V.), Department of Neuroscience (T.E.G.); Center for Translational Research in Neurodegenerative Diseases (T.E.G.), Department of Neurology (S.D., D.E.V.), and McKnight Brain Institute (S.D., D.E.V.), University of Florida, Gainesville; Center for Molecular and Behavioral Neuroscience (L.Z.), Rutgers University, Newark, NJ; Wein Center for Alzheimer's Disease and Memory Disorders (R.D., D.A.L.), Mount Sinai Medical Center, Miami Beach; Center for Cognitive Neuroscience and Aging (D.A.L.) and Department of Psychiatry and Behavioral Sciences (D.A.L.), University of Miami Miller School of Medicine; and Center for Advanced Technology and Education (M.A.), Florida International University, Miami.
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8
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Müller HP, Roselli F, Rasche V, Kassubek J. Diffusion Tensor Imaging-Based Studies at the Group-Level Applied to Animal Models of Neurodegenerative Diseases. Front Neurosci 2020; 14:734. [PMID: 32982659 PMCID: PMC7487414 DOI: 10.3389/fnins.2020.00734] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Accepted: 06/22/2020] [Indexed: 12/11/2022] Open
Abstract
The understanding of human and non-human microstructural brain alterations in the course of neurodegenerative diseases has substantially improved by the non-invasive magnetic resonance imaging (MRI) technique of diffusion tensor imaging (DTI). Animal models (including disease or knockout models) allow for a variety of experimental manipulations, which are not applicable to humans. Thus, the DTI approach provides a promising tool for cross-species cross-sectional and longitudinal investigations of the neurobiological targets and mechanisms of neurodegeneration. This overview with a systematic review focuses on the principles of DTI analysis as used in studies at the group level in living preclinical models of neurodegeneration. The translational aspect from in-vivo animal models toward (clinical) applications in humans is covered as well as the DTI-based research of the non-human brains' microstructure, the methodological aspects in data processing and analysis, and data interpretation at different abstraction levels. The aim of integrating DTI in multiparametric or multimodal imaging protocols will allow the interrogation of DTI data in terms of directional flow of information and may identify the microstructural underpinnings of neurodegeneration-related patterns.
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Affiliation(s)
| | - Francesco Roselli
- Department of Neurology, University of Ulm, Ulm, Germany.,German Center for Neurodegenerative Diseases (DZNE), Ulm, Germany
| | - Volker Rasche
- Core Facility Small Animal MRI, University of Ulm, Ulm, Germany
| | - Jan Kassubek
- Department of Neurology, University of Ulm, Ulm, Germany
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9
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Fernández-Cabello S, Kronbichler M, Van Dijk KRA, Goodman JA, Spreng RN, Schmitz TW. Basal forebrain volume reliably predicts the cortical spread of Alzheimer's degeneration. Brain 2020; 143:993-1009. [PMID: 32203580 PMCID: PMC7092749 DOI: 10.1093/brain/awaa012] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2019] [Revised: 11/21/2019] [Accepted: 12/04/2019] [Indexed: 12/25/2022] Open
Abstract
Alzheimer's disease neurodegeneration is thought to spread across anatomically and functionally connected brain regions. However, the precise sequence of spread remains ambiguous. The prevailing model used to guide in vivo human neuroimaging and non-human animal research assumes that Alzheimer's degeneration starts in the entorhinal cortices, before spreading to the temporoparietal cortex. Challenging this model, we previously provided evidence that in vivo markers of neurodegeneration within the nucleus basalis of Meynert (NbM), a subregion of the basal forebrain heavily populated by cortically projecting cholinergic neurons, precedes and predicts entorhinal degeneration. There have been few systematic attempts at directly comparing staging models using in vivo longitudinal biomarker data, and none to our knowledge testing if comparative evidence generalizes across independent samples. Here we addressed the sequence of pathological staging in Alzheimer's disease using two independent samples of the Alzheimer's Disease Neuroimaging Initiative (n1 = 284; n2 = 553) with harmonized CSF assays of amyloid-β and hyperphosphorylated tau (pTau), and longitudinal structural MRI data over 2 years. We derived measures of grey matter degeneration in a priori NbM and the entorhinal cortical regions of interest. To examine the spreading of degeneration, we used a predictive modelling strategy that tests whether baseline grey matter volume in a seed region accounts for longitudinal change in a target region. We demonstrated that predictive spread favoured the NbM→entorhinal over the entorhinal→NbM model. This evidence generalized across the independent samples. We also showed that CSF concentrations of pTau/amyloid-β moderated the observed predictive relationship, consistent with evidence in rodent models of an underlying trans-synaptic mechanism of pathophysiological spread. The moderating effect of CSF was robust to additional factors, including clinical diagnosis. We then applied our predictive modelling strategy to an exploratory whole-brain voxel-wise analysis to examine the spatial specificity of the NbM→entorhinal model. We found that smaller baseline NbM volumes predicted greater degeneration in localized regions of the entorhinal and perirhinal cortices. By contrast, smaller baseline entorhinal volumes predicted degeneration in the medial temporal cortex, recapitulating a prior influential staging model. Our findings suggest that degeneration of the basal forebrain cholinergic projection system is a robust and reliable upstream event of entorhinal and neocortical degeneration, calling into question a prevailing view of Alzheimer's disease pathogenesis.
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Affiliation(s)
- Sara Fernández-Cabello
- Department of Psychology, University of Salzburg, Salzburg, Austria
- Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
| | - Martin Kronbichler
- Department of Psychology, University of Salzburg, Salzburg, Austria
- Centre for Cognitive Neuroscience, University of Salzburg, Salzburg, Austria
- Neuroscience Institute, Christian-Doppler Medical Centre, Paracelsus Medical University, Salzburg, Austria
| | - Koene R A Van Dijk
- Clinical and Translational Imaging, Early Clinical Development, Pfizer Inc, Cambridge, MA, USA
| | - James A Goodman
- Clinical and Translational Imaging, Early Clinical Development, Pfizer Inc, Cambridge, MA, USA
| | - R Nathan Spreng
- Laboratory of Brain and Cognition, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
- Departments of Psychiatry and Psychology, McGill University, Montreal, QC, Canada
- Douglas Mental Health University Institute, Verdun, QC, Canada
- McConnell Brain Imaging Centre, McGill University, Montreal, QC, Canada
| | - Taylor W Schmitz
- Brain and Mind Institute, Western University, London, ON, Canada
- Department of Physiology and Pharmacology, Western University, London, ON, Canada
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10
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Meier S, Alfonsi F, Kurniawan ND, Milne MR, Kasherman MA, Delogu A, Piper M, Coulson EJ. The p75 neurotrophin receptor is required for the survival of neuronal progenitors and normal formation of the basal forebrain, striatum, thalamus and neocortex. Development 2019; 146:dev.181933. [PMID: 31488566 DOI: 10.1242/dev.181933] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Accepted: 08/19/2019] [Indexed: 11/20/2022]
Abstract
During development, the p75 neurotrophin receptor (p75NTR) is widely expressed in the nervous system where it regulates neuronal differentiation, migration and axonal outgrowth. p75NTR also mediates the survival and death of newly born neurons, with functional outcomes being dependent on both timing and cellular context. Here, we show that knockout of p75NTR from embryonic day 10 (E10) in neural progenitors using a conditional Nestin-Cre p75NTR floxed mouse causes increased apoptosis of progenitor cells. By E14.5, the number of Tbr2-positive progenitor cells was significantly reduced and the rate of neurogenesis was halved. Furthermore, in adult knockout mice, there were fewer cortical pyramidal neurons, interneurons, cholinergic basal forebrain neurons and striatal neurons, corresponding to a relative reduction in volume of these structures. Thalamic midline fusion during early postnatal development was also impaired in Nestin-Cre p75NTR floxed mice, indicating a novel role for p75NTR in the formation of this structure. The phenotype of this strain demonstrates that p75NTR regulates multiple aspects of brain development, including cortical progenitor cell survival, and that expression during early neurogenesis is required for appropriate formation of telencephalic structures.
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Affiliation(s)
- Sonja Meier
- Queensland Brain Institute, The University of Queensland, 4072 Brisbane, Australia
| | - Fabienne Alfonsi
- Queensland Brain Institute, The University of Queensland, 4072 Brisbane, Australia
| | - Nyoman D Kurniawan
- Centre for Advanced Imaging, The University of Queensland, 4072 Brisbane, Australia
| | - Michael R Milne
- School of Biomedical Sciences, The University of Queensland, 4072 Brisbane, Australia
| | - Maria A Kasherman
- Griffith Institute for Drug Discovery, Griffith University, 4122 Brisbane, Australia
| | - Alessio Delogu
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, Kings College, London SE5 9RX, UK
| | - Michael Piper
- Queensland Brain Institute, The University of Queensland, 4072 Brisbane, Australia
| | - Elizabeth J Coulson
- Queensland Brain Institute, The University of Queensland, 4072 Brisbane, Australia .,School of Biomedical Sciences, The University of Queensland, 4072 Brisbane, Australia
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11
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Nizari S, Carare RO, Romero IA, Hawkes CA. 3D Reconstruction of the Neurovascular Unit Reveals Differential Loss of Cholinergic Innervation in the Cortex and Hippocampus of the Adult Mouse Brain. Front Aging Neurosci 2019; 11:172. [PMID: 31333445 PMCID: PMC6620643 DOI: 10.3389/fnagi.2019.00172] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Accepted: 06/20/2019] [Indexed: 01/02/2023] Open
Abstract
Increasing evidence supports a role for cerebrovasculature dysfunction in the etiology of Alzheimer’s disease (AD). Blood vessels in the brain are composed of a collection of cells and acellular material that comprise the neurovascular unit (NVU). The NVU in the hippocampus and cortex receives innervation from cholinergic neurons that originate in the basal forebrain. Death of these neurons and their nerve fibers is an early feature of AD. However, the effect of the loss of cholinergic innervation on the NVU is not well characterized. The purpose of this study was to evaluate the effect of the loss of cholinergic innervation of components of the NVU at capillaries, arteries and veins in the hippocampus and cortex. Adult male C57BL/6 mice received an intracerebroventricular injection of the immunotoxin p75NTR mu-saporin to induce the loss of cholinergic neurons. Quadruple labeling immunohistochemistry and 3D reconstruction were carried out to characterize specific points of contact between cholinergic fibers and collagen IV, smooth muscle cells and astrocyte endfeet. Innate differences were observed between vessels of the hippocampus and cortex of control mice, including a greater amount of cholinergic contact with perivascular astrocytes in hippocampal capillaries and a thicker basement membrane in hippocampal veins. Saporin treatment induced a loss of cholinergic innervation at the arterial basement membrane and smooth muscle cells of both the hippocampus and the cortex. In the cortex, there was an additional loss of innervation at the astrocytic endfeet. The current results suggest that cortical arteries are more strongly affected by cholinergic denervation than arteries in the hippocampus. This regional variation may have implications for the etiology of the vascular pathology that develops in AD.
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Affiliation(s)
- Shereen Nizari
- School of Life, Health and Chemical Science, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Milton Keynes, United Kingdom
| | - Roxana O Carare
- Clinical and Experimental Sciences, Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Ignacio A Romero
- School of Life, Health and Chemical Science, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Milton Keynes, United Kingdom
| | - Cheryl A Hawkes
- School of Life, Health and Chemical Science, Faculty of Science, Technology, Engineering and Mathematics, The Open University, Milton Keynes, United Kingdom
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12
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Boskovic Z, Meier S, Wang Y, Milne M, Onraet T, Tedoldi A, Coulson E. Regulation of cholinergic basal forebrain development, connectivity, and function by neurotrophin receptors. Neuronal Signal 2019; 3:NS20180066. [PMID: 32269831 PMCID: PMC7104233 DOI: 10.1042/ns20180066] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2018] [Revised: 01/15/2019] [Accepted: 01/15/2019] [Indexed: 12/11/2022] Open
Abstract
Cholinergic basal forebrain (cBF) neurons are defined by their expression of the p75 neurotrophin receptor (p75NTR) and tropomyosin-related kinase (Trk) neurotrophin receptors in addition to cholinergic markers. It is known that the neurotrophins, particularly nerve growth factor (NGF), mediate cholinergic neuronal development and maintenance. However, the role of neurotrophin signalling in regulating adult cBF function is less clear, although in dementia, trophic signalling is reduced and p75NTR mediates neurodegeneration of cBF neurons. Here we review the current understanding of how cBF neurons are regulated by neurotrophins which activate p75NTR and TrkA, B or C to influence the critical role that these neurons play in normal cortical function, particularly higher order cognition. Specifically, we describe the current evidence that neurotrophins regulate the development of basal forebrain neurons and their role in maintaining and modifying mature basal forebrain synaptic and cortical microcircuit connectivity. Understanding the role neurotrophin signalling plays in regulating the precision of cholinergic connectivity will contribute to the understanding of normal cognitive processes and will likely provide additional ideas for designing improved therapies for the treatment of neurological disease in which cholinergic dysfunction has been demonstrated.
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Affiliation(s)
- Zoran Boskovic
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Sonja Meier
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Yunpeng Wang
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
- College of Forensic Science, Xi’an Jiaotong University, Shaanxi, China
| | - Michael R. Milne
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
| | - Tessa Onraet
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
| | - Angelo Tedoldi
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
| | - Elizabeth J. Coulson
- Queensland Brain Institute, The University of Queensland, Brisbane, Queensland, Australia
- Clem Jones Centre for Ageing Dementia Research, The University of Queensland, Brisbane, Queensland, Australia
- Faculty of Medicine, School of Biomedical Sciences, The University of Queensland, Brisbane, Queensland, Australia
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13
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Snow WM, Dale R, O'Brien-Moran Z, Buist R, Peirson D, Martin M, Albensi BC. In Vivo Detection of Gray Matter Neuropathology in the 3xTg Mouse Model of Alzheimer's Disease with Diffusion Tensor Imaging. J Alzheimers Dis 2018; 58:841-853. [PMID: 28505976 DOI: 10.3233/jad-170136] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
A diagnosis of Alzheimer's disease (AD), a neurodegenerative disorder accompanied by severe functional and cognitive decline, is based on clinical findings, with final confirmation of the disease at autopsy by the presence of amyloid-β (Aβ) plaques and neurofibrillary tangles. Given that microstructural brain alterations occur years prior to clinical symptoms, efforts to detect brain changes early could significantly enhance our ability to diagnose AD sooner. Diffusion tensor imaging (DTI), a type of MRI that characterizes the magnitude, orientation, and anisotropy of the diffusion of water in tissues, has been used to infer neuropathological changes in vivo. Its utility in AD, however, is still under investigation. The current study used DTI to examine brain regions susceptible to AD-related pathology; the cerebral cortex, entorhinal cortex, and hippocampus, in 12-14-month-old 3xTg AD mice that possess both Aβ plaques and neurofibrillary tangles. Mean diffusivity did not differ between 3xTg and control mice in any region. Decreased fractional anisotropy (p < 0.01) and axial diffusivity (p < 0.05) were detected only in the hippocampus, in which both congophilic Aβ plaques and hyperphosphorylated tau accumulation, consistent with neurofibrillary tangle formation, were detected. Pathological tau accumulation was seen in the cortex. The entorhinal cortex was largely spared from AD-related neuropathology. This is the first study to demonstrate DTI abnormalities in gray matter in a mouse model of AD in which both pathological hallmarks are present, suggesting the feasibility of DTI as a non-invasive means of detecting brain pathology in vivo in early-stage AD.
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Affiliation(s)
- Wanda M Snow
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.,Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Ryan Dale
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.,Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | | | - Richard Buist
- Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
| | - Danial Peirson
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.,Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
| | - Melanie Martin
- Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada.,Department of Physics, University of Winnipeg, Winnipeg, MB, Canada.,Department of Radiology, University of Manitoba, Winnipeg, MB, Canada
| | - Benedict C Albensi
- Division of Neurodegenerative Disorders, St. Boniface Hospital Albrechtsen Research Centre, Winnipeg, MB, Canada.,Department of Pharmacology & Therapeutics, University of Manitoba, Winnipeg, MB, Canada
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14
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Gimenez U, Boulan B, Mauconduit F, Taurel F, Leclercq M, Denarier E, Brocard J, Gory-Fauré S, Andrieux A, Lahrech H, Deloulme JC. 3D imaging of the brain morphology and connectivity defects in a model of psychiatric disorders: MAP6-KO mice. Sci Rep 2017; 7:10308. [PMID: 28871106 PMCID: PMC5583184 DOI: 10.1038/s41598-017-10544-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 08/10/2017] [Indexed: 11/03/2022] Open
Abstract
In the central nervous system, microtubule-associated protein 6 (MAP6) is expressed at high levels and is crucial for cognitive abilities. The large spectrum of social and cognitive impairments observed in MAP6-KO mice are reminiscent of the symptoms observed in psychiatric diseases, such as schizophrenia, and respond positively to long-term treatment with antipsychotics. MAP6-KO mice have therefore been proposed to be a useful animal model for these diseases. Here, we explored the brain anatomy in MAP6-KO mice using high spatial resolution 3D MRI, including a volumetric T1w method to image brain structures, and Diffusion Tensor Imaging (DTI) for white matter fiber tractography. 3D DTI imaging of neuronal tracts was validated by comparing results to optical images of cleared brains. Changes to brain architecture included reduced volume of the cerebellum and the thalamus and altered size, integrity and spatial orientation of some neuronal tracks such as the anterior commissure, the mammillary tract, the corpus callosum, the corticospinal tract, the fasciculus retroflexus and the fornix. Our results provide information on the neuroanatomical defects behind the neurological phenotype displayed in the MAP6-KO mice model and especially highlight a severe damage of the corticospinal tract with defasciculation at the location of the pontine nuclei.
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Affiliation(s)
- Ulysse Gimenez
- INSERM, U1205, BrainTech Lab, F-38000, Grenoble, France.,Univ. Grenoble Alpes, F-38000, Grenoble, France
| | - Benoit Boulan
- Univ. Grenoble Alpes, F-38000, Grenoble, France.,INSERM, U1216, Grenoble Institut des Neurosciences, F-38000, Grenoble, France
| | - Franck Mauconduit
- INSERM, U1205, BrainTech Lab, F-38000, Grenoble, France.,Univ. Grenoble Alpes, F-38000, Grenoble, France
| | - Fanny Taurel
- INSERM, U1205, BrainTech Lab, F-38000, Grenoble, France.,Univ. Grenoble Alpes, F-38000, Grenoble, France
| | - Maxime Leclercq
- INSERM, U1205, BrainTech Lab, F-38000, Grenoble, France.,Univ. Grenoble Alpes, F-38000, Grenoble, France
| | - Eric Denarier
- Univ. Grenoble Alpes, F-38000, Grenoble, France.,INSERM, U1216, Grenoble Institut des Neurosciences, F-38000, Grenoble, France.,Commissariat à l'Energie Atomique, BIG-GPC, F-38000, Grenoble, France
| | - Jacques Brocard
- Univ. Grenoble Alpes, F-38000, Grenoble, France.,INSERM, U1216, Grenoble Institut des Neurosciences, F-38000, Grenoble, France
| | - Sylvie Gory-Fauré
- Univ. Grenoble Alpes, F-38000, Grenoble, France.,INSERM, U1216, Grenoble Institut des Neurosciences, F-38000, Grenoble, France
| | - Annie Andrieux
- Univ. Grenoble Alpes, F-38000, Grenoble, France.,INSERM, U1216, Grenoble Institut des Neurosciences, F-38000, Grenoble, France.,Commissariat à l'Energie Atomique, BIG-GPC, F-38000, Grenoble, France
| | - Hana Lahrech
- INSERM, U1205, BrainTech Lab, F-38000, Grenoble, France. .,Univ. Grenoble Alpes, F-38000, Grenoble, France.
| | - Jean Christophe Deloulme
- Univ. Grenoble Alpes, F-38000, Grenoble, France. .,INSERM, U1216, Grenoble Institut des Neurosciences, F-38000, Grenoble, France.
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15
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Damaged fiber tracts of the nucleus basalis of Meynert in Parkinson's disease patients with visual hallucinations. Sci Rep 2017; 7:10112. [PMID: 28860465 PMCID: PMC5579278 DOI: 10.1038/s41598-017-10146-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 08/04/2017] [Indexed: 01/29/2023] Open
Abstract
Damage to fiber tracts connecting the nucleus basalis of Meynert (NBM) to the cerebral cortex may underlie the development of visual hallucinations (VH) in Parkinson’s disease (PD), possibly due to a loss of cholinergic innervation. This was investigated by comparing structural connectivity of the NBM using diffusion tensor imaging in 15 PD patients with VH (PD + VH), 40 PD patients without VH (PD − VH), and 15 age- and gender-matched controls. Fractional anisotropy (FA) and mean diffusivity (MD) of pathways connecting the NBM to the whole cerebral cortex and of regional NBM fiber tracts were compared between groups. In PD + VH patients, compared to controls, higher MD values were observed in the pathways connecting the NBM to the cerebral cortex, while FA values were normal. Regional analysis demonstrated a higher MD of parietal (p = 0.011) and occipital tracts (p = 0.027) in PD + VH, compared to PD − VH patients. We suggest that loss of structural connectivity between the NBM and posterior brain regions may contribute to the etiology of VH in PD. Future studies are needed to determine whether these findings could represent a sensitive marker for the hypothesized cholinergic deficit in PD + VH patients.
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16
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Badea A, Kane L, Anderson RJ, Qi Y, Foster M, Cofer GP, Medvitz N, Buckley AF, Badea AK, Wetsel WC, Colton CA. The fornix provides multiple biomarkers to characterize circuit disruption in a mouse model of Alzheimer's disease. Neuroimage 2016; 142:498-511. [PMID: 27521741 DOI: 10.1016/j.neuroimage.2016.08.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Revised: 06/23/2016] [Accepted: 08/09/2016] [Indexed: 12/19/2022] Open
Abstract
Multivariate biomarkers are needed for detecting Alzheimer's disease (AD), understanding its etiology, and quantifying the effect of therapies. Mouse models provide opportunities to study characteristics of AD in well-controlled environments that can help facilitate development of early interventions. The CVN-AD mouse model replicates multiple AD hallmark pathologies, and we identified multivariate biomarkers characterizing a brain circuit disruption predictive of cognitive decline. In vivo and ex vivo magnetic resonance imaging (MRI) revealed that CVN-AD mice replicate the hippocampal atrophy (6%), characteristic of humans with AD, and also present changes in subcortical areas. The largest effect was in the fornix (23% smaller), which connects the septum, hippocampus, and hypothalamus. In characterizing the fornix with diffusion tensor imaging, fractional anisotropy was most sensitive (20% reduction), followed by radial (15%) and axial diffusivity (2%), in detecting pathological changes. These findings were strengthened by optical microscopy and ultrastructural analyses. Ultrastructual analysis provided estimates of axonal density, diameters, and myelination-through the g-ratio, defined as the ratio between the axonal diameter, and the diameter of the axon plus the myelin sheath. The fornix had reduced axonal density (47% fewer), axonal degeneration (13% larger axons), and abnormal myelination (1.5% smaller g-ratios). CD68 staining showed that white matter pathology could be secondary to neuronal degeneration, or due to direct microglial attack. In conclusion, these findings strengthen the hypothesis that the fornix plays a role in AD, and can be used as a disease biomarker and as a target for therapy.
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Affiliation(s)
- Alexandra Badea
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Durham, NC 27710, USA.
| | - Lauren Kane
- Trinity College of Arts & Sciences, Duke University, Durham, NC 27710, USA
| | - Robert J Anderson
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Durham, NC 27710, USA
| | - Yi Qi
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Durham, NC 27710, USA
| | - Mark Foster
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Durham, NC 27710, USA
| | - Gary P Cofer
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Durham, NC 27710, USA
| | - Neil Medvitz
- Department of Pathology, and Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Anne F Buckley
- Department of Pathology, and Preston Robert Tisch Brain Tumor Center, Duke University Medical Center, Durham, NC 27710, USA
| | - Andreas K Badea
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Durham, NC 27710, USA
| | - William C Wetsel
- Departments of Psychiatry and Behavioral Sciences, Cell Biology, and Neurobiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Carol A Colton
- Department of Neurology, Duke University Medical Center, Durham, NC 27710, USA
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17
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Brueggen K, Dyrba M, Barkhof F, Hausner L, Filippi M, Nestor PJ, Hauenstein K, Klöppel S, Grothe MJ, Kasper E, Teipel SJ. Basal Forebrain and Hippocampus as Predictors of Conversion to Alzheimer's Disease in Patients with Mild Cognitive Impairment - A Multicenter DTI and Volumetry Study. J Alzheimers Dis 2016; 48:197-204. [PMID: 26401940 DOI: 10.3233/jad-150063] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Hippocampal grey matter (GM) atrophy predicts conversion from mild cognitive impairment (MCI) to Alzheimer's disease (AD). Pilot data suggests that mean diffusivity (MD) in the hippocampus, as measured with diffusion tensor imaging (DTI), may be a more accurate predictor of conversion than hippocampus volume. In addition, previous studies suggest that volume of the cholinergic basal forebrain may reach a diagnostic accuracy superior to hippocampal volume in MCI. OBJECTIVE The present study investigated whether increased MD and decreased volume of the hippocampus, the basal forebrain and other AD-typical regions predicted time to conversion from MCI to AD dementia. METHODS 79 MCI patients with DTI and T1-weighted magnetic resonance imaging (MRI) were retrospectively included from the European DTI Study in Dementia (EDSD) dataset. Of these participants, 35 converted to AD dementia after 6-46 months (mean: 21 months). We used Cox regression to estimate the relative conversion risk predicted by MD values and GM volumes, controlling for age, gender, education and center. RESULTS Decreased GM volume in all investigated regions predicted an increased risk for conversion. Additionally, increased MD in the right basal forebrain predicted increased conversion risk. Reduced volume of the right hippocampus was the only significant predictor in a stepwise model combining all predictor variables. CONCLUSION Volume reduction of the hippocampus, the basal forebrain and other AD-related regions was predictive of increased risk for conversion from MCI to AD. In this study, volume was superior to MD in predicting conversion.
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Affiliation(s)
| | - Martin Dyrba
- DZNE, German Center for Neurodegenerative Diseases, Rostock, Germany.,MMIS group, University of Rostock, Rostock, Germany
| | - Frederik Barkhof
- Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, Netherlands
| | - Lucrezia Hausner
- Department of Geriatric Psychiatry, Zentralinstitut für Seelische Gesundheit Mannheim, University of Heidelberg, Mannheim, Germany
| | - Massimo Filippi
- Neuroimaging Research Unit, Institute of Experimental Neurology, Division of Neuroscience, Scientific Institute and University Vita-Salute San Raffaele, Milano, Italy
| | - Peter J Nestor
- DZNE, German Center for Neurodegenerative Diseases, Magdeburg, Germany
| | | | - Stefan Klöppel
- Department of Psychiatry and Psychotherapy, Freiburg Brain Imaging, University Clinic Freiburg, Freiburg, Germany
| | - Michel J Grothe
- DZNE, German Center for Neurodegenerative Diseases, Rostock, Germany
| | - Elisabeth Kasper
- Department of Psychosomatic Medicine, University Medicine Rostock, Rostock, Germany
| | - Stefan J Teipel
- DZNE, German Center for Neurodegenerative Diseases, Rostock, Germany.,Department of Psychosomatic Medicine, University Medicine Rostock, Rostock, Germany
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Daulatzai MA. Dysfunctional Sensory Modalities, Locus Coeruleus, and Basal Forebrain: Early Determinants that Promote Neuropathogenesis of Cognitive and Memory Decline and Alzheimer’s Disease. Neurotox Res 2016; 30:295-337. [DOI: 10.1007/s12640-016-9643-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 06/08/2016] [Accepted: 06/10/2016] [Indexed: 12/22/2022]
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Holmes HE, Colgan N, Ismail O, Ma D, Powell NM, O'Callaghan JM, Harrison IF, Johnson RA, Murray TK, Ahmed Z, Heggenes M, Fisher A, Cardoso MJ, Modat M, Walker-Samuel S, Fisher EMC, Ourselin S, O'Neill MJ, Wells JA, Collins EC, Lythgoe MF. Imaging the accumulation and suppression of tau pathology using multiparametric MRI. Neurobiol Aging 2016; 39:184-94. [PMID: 26923415 PMCID: PMC4782737 DOI: 10.1016/j.neurobiolaging.2015.12.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 12/08/2015] [Accepted: 12/09/2015] [Indexed: 01/30/2023]
Abstract
Mouse models of Alzheimer's disease have served as valuable tools for investigating pathogenic mechanisms relating to neurodegeneration, including tau-mediated and neurofibrillary tangle pathology-a major hallmark of the disease. In this work, we have used multiparametric magnetic resonance imaging (MRI) in a longitudinal study of neurodegeneration in the rTg4510 mouse model of tauopathy, a subset of which were treated with doxycycline at different time points to suppress the tau transgene. Using this paradigm, we investigated the sensitivity of multiparametric MRI to both the accumulation and suppression of pathologic tau. Tau-related atrophy was discernible from 5.5 months within the cortex and hippocampus. We observed markedly less atrophy in the treated rTg4510 mice, which was enhanced after doxycycline intervention from 3.5 months. We also observed differences in amide proton transfer, cerebral blood flow, and diffusion tensor imaging parameters in the rTg4510 mice, which were significantly less altered after doxycycline treatment. We propose that these non-invasive MRI techniques offer insight into pathologic mechanisms underpinning Alzheimer's disease that may be important when evaluating emerging therapeutics targeting one of more of these processes.
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Affiliation(s)
- Holly E Holmes
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK.
| | - Niall Colgan
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
| | - Ozama Ismail
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
| | - Da Ma
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK; Translational Imaging Group, Centre for Medical Image Computing, University College London, London, UK
| | - Nick M Powell
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK; Translational Imaging Group, Centre for Medical Image Computing, University College London, London, UK
| | - James M O'Callaghan
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
| | - Ian F Harrison
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
| | - Ross A Johnson
- Tailored Therapeutics, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | | | | | | | | | - M J Cardoso
- Translational Imaging Group, Centre for Medical Image Computing, University College London, London, UK
| | - Marc Modat
- Translational Imaging Group, Centre for Medical Image Computing, University College London, London, UK
| | - Simon Walker-Samuel
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
| | - Elizabeth M C Fisher
- Department of Neurodegenerative Diseases, Institute of Neurology, University College London, London, UK
| | - Sebastien Ourselin
- Translational Imaging Group, Centre for Medical Image Computing, University College London, London, UK
| | | | - Jack A Wells
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
| | - Emily C Collins
- Tailored Therapeutics, Eli Lilly and Company, Lilly Corporate Center, Indianapolis, IN, USA
| | - Mark F Lythgoe
- Division of Medicine, Centre for Advanced Biomedical Imaging, University College London, London, UK
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Calabrese E, Badea A, Cofer G, Qi Y, Johnson GA. A Diffusion MRI Tractography Connectome of the Mouse Brain and Comparison with Neuronal Tracer Data. Cereb Cortex 2015; 25:4628-37. [PMID: 26048951 PMCID: PMC4715247 DOI: 10.1093/cercor/bhv121] [Citation(s) in RCA: 144] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Interest in structural brain connectivity has grown with the understanding that abnormal neural connections may play a role in neurologic and psychiatric diseases. Small animal connectivity mapping techniques are particularly important for identifying aberrant connectivity in disease models. Diffusion magnetic resonance imaging tractography can provide nondestructive, 3D, brain-wide connectivity maps, but has historically been limited by low spatial resolution, low signal-to-noise ratio, and the difficulty in estimating multiple fiber orientations within a single image voxel. Small animal diffusion tractography can be substantially improved through the combination of ex vivo MRI with exogenous contrast agents, advanced diffusion acquisition and reconstruction techniques, and probabilistic fiber tracking. Here, we present a comprehensive, probabilistic tractography connectome of the mouse brain at microscopic resolution, and a comparison of these data with a neuronal tracer-based connectivity data from the Allen Brain Atlas. This work serves as a reference database for future tractography studies in the mouse brain, and demonstrates the fundamental differences between tractography and neuronal tracer data.
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Affiliation(s)
- Evan Calabrese
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Alexandra Badea
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Gary Cofer
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - Yi Qi
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
| | - G Allan Johnson
- Center for In Vivo Microscopy, Duke University Medical Center, Department of Radiology, Duke University Medical Center, Durham, NC 27710, USA
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Delgado y Palacios R, Verhoye M, Henningsen K, Wiborg O, Van der Linden A. Diffusion kurtosis imaging and high-resolution MRI demonstrate structural aberrations of caudate putamen and amygdala after chronic mild stress. PLoS One 2014; 9:e95077. [PMID: 24740310 PMCID: PMC3989315 DOI: 10.1371/journal.pone.0095077] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2011] [Accepted: 03/24/2014] [Indexed: 01/02/2023] Open
Abstract
The pathophysiology of major depressive disorder (MDD) and other stress related disorders has been associated with aberrations in the hippocampus and the frontal brain areas. More recently, other brain regions, such as the caudate nucleus, the putamen and the amygdala have also been suggested to play a role in the development of mood disorders. By exposing rats to a variety of stressors over a period of eight weeks, different phenotypes, i.e. stress susceptible (anhedonic-like) and stress resilient animals, can be discriminated based on the sucrose consumption test. The anhedonic-like animals are a well validated model for MDD. Previously, we reported that in vivo diffusion kurtosis imaging (DKI) of the hippocampus shows altered diffusion properties in chronically stressed rats independent of the hedonic state and that the shape of the right hippocampus is differing among the three groups, including unchallenged controls. In this study we evaluated diffusion properties in the prefrontal cortex, caudate putamen (CPu) and amygdala of anhedonic-like and resilient phenotypes and found that mean kurtosis in the CPu was significantly different between the anhedonic-like and resilient animals. In addition, axial diffusion and radial diffusion were increased in the stressed animal groups in the CPu and the amygdala, respectively. Furthermore, we found that the CPu/brain volume ratio was increased significantly in anhedonic-like animals as compared with control animals. Concurrently, our results indicate that the effects of chronic stress on the brain are not lateralized in these regions. These findings confirm the involvement of the CPu and the amygdala in stress related disorders and MDD. Additionally, we also show that DKI is a potentially important tool to promote the objective assessment of psychiatric disorders.
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Affiliation(s)
| | | | - Kim Henningsen
- Centre for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
| | - Ove Wiborg
- Centre for Psychiatric Research, Aarhus University Hospital, Risskov, Denmark
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In vivo quantitative whole-brain diffusion tensor imaging analysis of APP/PS1 transgenic mice using voxel-based and atlas-based methods. Neuroradiology 2013; 55:1027-1038. [PMID: 23644540 DOI: 10.1007/s00234-013-1195-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 04/15/2013] [Indexed: 12/24/2022]
Abstract
INTRODUCTION Diffusion tensor imaging (DTI) has been applied to characterize the pathological features of Alzheimer's disease (AD) in a mouse model, although little is known about whether these features are structure specific. Voxel-based analysis (VBA) and atlas-based analysis (ABA) are good complementary tools for whole-brain DTI analysis. The purpose of this study was to identify the spatial localization of disease-related pathology in an AD mouse model. METHODS VBA and ABA quantification were used for the whole-brain DTI analysis of nine APP/PS1 mice and wild-type (WT) controls. Multiple scalar measurements, including fractional anisotropy (FA), trace, axial diffusivity (DA), and radial diffusivity (DR), were investigated to capture the various types of pathology. The accuracy of the image transformation applied for VBA and ABA was evaluated by comparing manual and atlas-based structure delineation using kappa statistics. Following the MR examination, the brains of the animals were analyzed for microscopy. RESULTS Extensive anatomical alterations were identified in APP/PS1 mice, in both the gray matter areas (neocortex, hippocampus, caudate putamen, thalamus, hypothalamus, claustrum, amygdala, and piriform cortex) and the white matter areas (corpus callosum/external capsule, cingulum, septum, internal capsule, fimbria, and optic tract), evidenced by an increase in FA or DA, or both, compared to WT mice (p < 0.05, corrected). The average kappa value between manual and atlas-based structure delineation was approximately 0.8, and there was no significant difference between APP/PS1 and WT mice (p > 0.05). The histopathological changes in the gray matter areas were confirmed by microscopy studies. DTI did, however, demonstrate significant changes in white matter areas, where the difference was not apparent by qualitative observation of a single-slice histological specimen. CONCLUSION This study demonstrated the structure-specific nature of pathological changes in APP/PS1 mouse, and also showed the feasibility of applying whole-brain analysis methods to the investigation of an AD mouse model.
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