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Lv Q, Zhang J, Pan Y, Liu X, Miao L, Peng J, Song L, Zou Y, Chen X. Somatosensory Deficits After Stroke: Insights From MRI Studies. Front Neurol 2022; 13:891283. [PMID: 35911919 PMCID: PMC9328992 DOI: 10.3389/fneur.2022.891283] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 06/15/2022] [Indexed: 11/28/2022] Open
Abstract
Somatosensory deficits after stroke are a major health problem, which can impair patients' health status and quality of life. With the developments in human brain mapping techniques, particularly magnetic resonance imaging (MRI), many studies have applied those techniques to unravel neural substrates linked to apoplexy sequelae. Multi-parametric MRI is a vital method for the measurement of stroke and has been applied to diagnose stroke severity, predict outcome and visualize changes in activation patterns during stroke recovery. However, relatively little is known about the somatosensory deficits after stroke and their recovery. This review aims to highlight the utility and importance of MRI techniques in the field of somatosensory deficits and synthesizes corresponding articles to elucidate the mechanisms underlying the occurrence and recovery of somatosensory symptoms. Here, we start by reviewing the anatomic and functional features of the somatosensory system. And then, we provide a discussion of MRI techniques and analysis methods. Meanwhile, we present the application of those techniques and methods in clinical studies, focusing on recent research advances and the potential for clinical translation. Finally, we identify some limitations and open questions of current imaging studies that need to be addressed in future research.
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Affiliation(s)
- Qiuyi Lv
- Department of Neurology and Stroke Center, Dongzhimen Hospital, The First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Junning Zhang
- Department of Integrative Oncology, China-Japan Friendship Hospital, Beijing, China
| | - Yuxing Pan
- Institute of Neuroscience, Chinese Academy of Science, Shanghai, China
| | - Xiaodong Liu
- School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Beijing, China
| | | | - Jing Peng
- Department of Neurology and Stroke Center, Dongzhimen Hospital, The First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Lei Song
- Department of Neurology and Stroke Center, Dongzhimen Hospital, The First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Yihuai Zou
- Department of Neurology and Stroke Center, Dongzhimen Hospital, The First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Xing Chen
- Department of Neurology and Stroke Center, Dongzhimen Hospital, The First Affiliated Hospital of Beijing University of Chinese Medicine, Beijing, China
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2
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Syeda W, Ermine CM, Khilf MS, Wright D, Brait VH, Nithianantharajah J, Kolbe S, Johnston LA, Thompson LH, Brodtmann A. Long-term structural brain changes in adult rats after mild ischaemic stroke. Brain Commun 2022; 4:fcac185. [PMID: 35898722 PMCID: PMC9309495 DOI: 10.1093/braincomms/fcac185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 03/09/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022] Open
Abstract
Preclinical studies of remote degeneration have largely focused on brain changes over the first few days or weeks after stroke. Accumulating evidence suggests that neurodegeneration occurs in other brain regions remote to the site of infarction for months and even years following ischaemic stroke. Brain atrophy appears to be driven by both axonal degeneration and widespread brain inflammation. The evolution and duration of these changes are increasingly being described in human studies, using advanced brain imaging techniques. Here, we sought to investigate long-term structural brain changes in a model of mild focal ischaemic stroke following injection of endothlin-1 in adult Long–Evans rats (n = 14) compared with sham animals (n = 10), over a clinically relevant time-frame of 48 weeks. Serial structural and diffusion-weighted MRI data were used to assess dynamic volume and white matter trajectories. We observed dynamic regional brain volume changes over the 48 weeks, reflecting both normal changes with age in sham animals and neurodegeneration in regions connected to the infarct following ischaemia. Ipsilesional cortical volume loss peaked at 24 weeks but was less prominent at 36 and 48 weeks. We found significantly reduced fractional anisotropy in both ipsi- and contralesional motor cortex and cingulum bundle regions of infarcted rats (P < 0.05) from 4 to 36 weeks, suggesting ongoing white matter degeneration in tracts connected to but distant from the stroke. We conclude that there is evidence of significant cortical atrophy and white matter degeneration up to 48 weeks following infarct, consistent with enduring, pervasive stroke-related degeneration.
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Affiliation(s)
- Warda Syeda
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
- Melbourne Neuropsychiatry Centre, The University of Melbourne , Parkville, Victoria , Australia
| | - Charlotte M Ermine
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
| | - Mohamed Salah Khilf
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
| | - David Wright
- Department of Neuroscience, Monash University , Clayton , Australia
| | - Vanessa H Brait
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
| | - Jess Nithianantharajah
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
| | - Scott Kolbe
- Department of Neuroscience, Monash University , Clayton , Australia
| | - Leigh A Johnston
- The Melbourne Brain Centre Imaging Unit, The University of Melbourne , Parkville, Victoria , Australia
- Department of Biomedical Engineering, The University of Melbourne , Parkville, Victoria , Australia
| | - Lachlan H Thompson
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
| | - Amy Brodtmann
- The Florey Institute of Neuroscience and Mental Health , Parkville, Victoria , Australia
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3
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Park KW, Ju H, Kim ID, Cave JW, Guo Y, Wang W, Wu Z, Cho S. Delayed Infiltration of Peripheral Monocyte Contributes to Phagocytosis and Transneuronal Degeneration in Chronic Stroke. Stroke 2022; 53:2377-2388. [PMID: 35656826 DOI: 10.1161/strokeaha.122.038701] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Mononuclear phagocytes, including monocyte-derived macrophages (MDMs) and microglia, contribute to infarct development as well as tissue repair in the postischemic brain. Here, we identify the origin and function of MDMs in the brain during poststroke repair processes. METHODS Adult mice were subjected to transient middle cerebral artery occlusion. Longitudinal brain atrophy and secondary degeneration were evaluated during acute to recovery phases of stroke. Adoptive transfer of GFP+ splenocytes into asplenic mice was used to distinguish MDMs from resident microglia. Fluorescence beads were injected into stroked animals to examine phagocytic function. RESULTS Progressive atrophy and neuronal degeneration in remote regions were observed in chronic stroke, which also was accompanied by MDM infiltration into the ipsilateral hemisphere. Compared with microglia, MDMs had significantly higher phagocytic activity. MDM trafficking and phagocytosis was spatiotemporally regulated with acute and prolonged infiltration into infarcted tissue, as well as delayed entry in remote areas such as the thalamus and substantia nigra. CONCLUSIONS The stepwise and long-lasting involvement of MDMs at multiple poststroke stages shows that MDMs have a role in progressive stroke-induced injury and repair processes. These findings suggest that manipulating monocyte entry at different stroke stages may be an effective immune-based strategy to limit injury propagation in chronic stroke.
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Affiliation(s)
- Keun Woo Park
- Burke Neurological Institute, White Plains, NY (K.W.P., H.J., I.-d.K., Y.G., S.C.).,Feil Brain Mind Research Institute, Weill Cornell Medicine, NY (K.W.P., S.C.)
| | - Hyunwoo Ju
- Burke Neurological Institute, White Plains, NY (K.W.P., H.J., I.-d.K., Y.G., S.C.)
| | - Il-Doo Kim
- Burke Neurological Institute, White Plains, NY (K.W.P., H.J., I.-d.K., Y.G., S.C.)
| | - John W Cave
- InVitro Cell Research LLC, Englewood, NJ (J.W.C.)
| | - Yang Guo
- Burke Neurological Institute, White Plains, NY (K.W.P., H.J., I.-d.K., Y.G., S.C.)
| | - Wei Wang
- Department of Cell, Developmental and Regenerative Biology and Department of Neuroscience, Icahn School of Medicine at Mount Sinai, NY (W.W., Z.W.)
| | - Zhuhao Wu
- Department of Cell, Developmental and Regenerative Biology and Department of Neuroscience, Icahn School of Medicine at Mount Sinai, NY (W.W., Z.W.)
| | - Sunghee Cho
- Burke Neurological Institute, White Plains, NY (K.W.P., H.J., I.-d.K., Y.G., S.C.).,Feil Brain Mind Research Institute, Weill Cornell Medicine, NY (K.W.P., S.C.)
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4
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Houlton J, Zubkova OV, Clarkson AN. Recovery of Post-Stroke Spatial Memory and Thalamocortical Connectivity Following Novel Glycomimetic and rhBDNF Treatment. Int J Mol Sci 2022; 23:ijms23094817. [PMID: 35563207 PMCID: PMC9101131 DOI: 10.3390/ijms23094817] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2022] [Revised: 04/22/2022] [Accepted: 04/25/2022] [Indexed: 12/10/2022] Open
Abstract
Stroke-induced cognitive impairments remain of significant concern, with very few treatment options available. The involvement of glycosaminoglycans in neuroregenerative processes is becoming better understood and recent advancements in technology have allowed for cost-effective synthesis of novel glycomimetics. The current study evaluated the therapeutic potential of two novel glycomimetics, compound A and G, when administered systemically five-days post-photothrombotic stroke to the PFC. As glycosaminoglycans are thought to facilitate growth factor function, we also investigated the combination of our glycomimetics with intracerebral, recombinant human brain-derived neurotrophic factor (rhBDNF). C56BL/6J mice received sham or stroke surgery and experimental treatment (day-5), before undergoing the object location recognition task (OLRT). Four-weeks post-surgery, animals received prelimbic injections of the retrograde tracer cholera toxin B (CTB), before tissue was collected for quantification of thalamo-PFC connectivity and reactive astrogliosis. Compound A or G treatment alone modulated a degree of reactive astrogliosis yet did not influence spatial memory performance. Contrastingly, compound G+rhBDNF treatment significantly improved spatial memory, dampened reactive astrogliosis and limited stroke-induced loss of connectivity between the PFC and midline thalamus. As rhBDNF treatment had negligible effects, these findings support compound A acted synergistically to enhance rhBDNF to restrict secondary degeneration and facilitate functional recovery after PFC stroke.
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Affiliation(s)
- Josh Houlton
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin 9054, New Zealand;
| | - Olga V. Zubkova
- The Ferrier Research Institute, Gracefield Research Centre, Victoria University of Wellington, 69 Gracefield Road, Lower Hutt 5040, New Zealand;
| | - Andrew N. Clarkson
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin 9054, New Zealand;
- Correspondence: ; Tel./Fax: +64-3-279-7326
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5
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Ermine CM, Nithianantharajah J, O'Brien K, Kauhausen JA, Frausin S, Oman A, Parsons MW, Brait VH, Brodtmann A, Thompson LH. Hemispheric cortical atrophy and chronic microglial activation following mild focal ischemic stroke in adult male rats. J Neurosci Res 2021; 99:3222-3237. [PMID: 34651338 DOI: 10.1002/jnr.24939] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 07/14/2021] [Indexed: 01/05/2023]
Abstract
Animal modeling has played an important role in our understanding of the pathobiology of stroke. The vast majority of this research has focused on the acute phase following severe forms of stroke that result in clear behavioral deficits. Human stroke, however, can vary widely in severity and clinical outcome. There is a rapidly building body of work suggesting that milder ischemic insults can precipitate functional impairment, including cognitive decline, that continues through the chronic phase after injury. Here we show that a small infarction localized to the frontal motor cortex of rats following injection of endothelin-1 results in an essentially asymptomatic state based on motor and cognitive testing, and yet produces significant histopathological change including remote atrophy and inflammation that persists up to 1 year. While there is understandably a major focus in stroke research on mitigating the acute consequences of primary infarction, these results point to progressive atrophy and chronic inflammation as additional targets for intervention in the chronic phase after injury. The present rodent model provides an important platform for further work in this area.
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Affiliation(s)
- Charlotte M Ermine
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Jess Nithianantharajah
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Katrina O'Brien
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Jessica A Kauhausen
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Stefano Frausin
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Alexander Oman
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Mark W Parsons
- Melbourne Brain Centre, University of Melbourne, Melbourne, VIC, Australia.,Department of Neurology, University of New Wales South Western Clinical School, Ingham Institute for Applied Medical Research, Liverpool, NSW, Australia
| | - Vanessa H Brait
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
| | - Amy Brodtmann
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia.,Department of Neurology, Austin Health, Melbourne, VIC, Australia.,Eastern Cognitive Disorders Clinic, Eastern Health, Monash University, Clayton, VIC, Australia
| | - Lachlan H Thompson
- The Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, VIC, Australia
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6
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Gottlieb E, Egorova N, Khlif MS, Khan W, Werden E, Pase MP, Howard M, Brodtmann A. Regional neurodegeneration correlates with sleep-wake dysfunction after stroke. Sleep 2021; 43:5813630. [PMID: 32249910 DOI: 10.1093/sleep/zsaa054] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 03/19/2020] [Indexed: 12/13/2022] Open
Abstract
Sleep-wake disruption is a key modifiable risk factor and sequela of stroke. The pathogenesis of poststroke sleep dysfunction is unclear. It is not known whether poststroke sleep pathology is due to focal infarction to sleep-wake hubs or to accelerated poststroke neurodegeneration in subcortical structures after stroke. We characterize the first prospective poststroke regional brain volumetric and whole-brain, fiber-specific, white matter markers of objectively measured sleep-wake dysfunction. We hypothesized that excessively long sleep (>8 h) duration and poor sleep efficiency (<80%) measured using the SenseWear Armband 3-months poststroke (n = 112) would be associated with reduced regional brain volumes of a priori-selected sleep-wake regions of interest when compared to healthy controls with optimal sleep characteristics (n = 35). We utilized a novel technique known as a whole-brain fixel-based analysis to investigate the fiber-specific white matter differences in participants with long sleep duration. Stroke participants with long sleep (n = 24) duration exhibited reduced regional volumes of the ipsilesional thalamus and contralesional amygdala when compared with controls. Poor sleep efficiency after stroke (n = 29) was associated with reduced ipsilesional thalamus, contralesional hippocampus, and contralesional amygdala volumes. Whole-brain fixel-based analyses revealed widespread macrostructural degeneration to the corticopontocerebellar tract in stroke participants with long sleep duration, with fiber reductions of up to 40%. Neurodegeneration to subcortical structures, which appear to be vulnerable to accelerated brain volume loss after stroke, may drive sleep-wake deficiencies poststroke, independent of lesion characteristics and confounding comorbidities. We discuss these findings in the context of the clinicopathological implications of sleep-related neurodegeneration and attempt to corroborate previous mechanistic-neuroanatomical findings.
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Affiliation(s)
- Elie Gottlieb
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,University of Melbourne, Melbourne, Victoria, Australia
| | - Natalia Egorova
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,University of Melbourne, Melbourne, Victoria, Australia
| | - Mohamed S Khlif
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,University of Melbourne, Melbourne, Victoria, Australia
| | - Wasim Khan
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,University of Melbourne, Melbourne, Victoria, Australia.,Department of Neuroimaging, Institute of Psychiatry, Psychology, and Neuroscience (IoPPN), King's College, London, UK
| | - Emilio Werden
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,University of Melbourne, Melbourne, Victoria, Australia
| | - Matthew P Pase
- Turner Institute for Brain and Mental Health, School of Psychological Sciences, Monash University, Melbourne, Victoria, Australia.,Harvard T.H. Chan School of Public Health, Harvard University, MA
| | - Mark Howard
- University of Melbourne, Melbourne, Victoria, Australia.,Austin Health, Heidelberg, Victoria, Australia.,Institute for Breathing and Sleep, Heidelberg, Victoria, Australia
| | - Amy Brodtmann
- The Florey Institute of Neuroscience and Mental Health, Melbourne, Victoria, Australia.,University of Melbourne, Melbourne, Victoria, Australia
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7
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Houlton J, Barwick D, Clarkson AN. Frontal cortex stroke-induced impairment in spatial working memory on the trial-unique nonmatching-to-location task in mice. Neurobiol Learn Mem 2020; 177:107355. [PMID: 33276070 DOI: 10.1016/j.nlm.2020.107355] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2020] [Revised: 10/27/2020] [Accepted: 11/29/2020] [Indexed: 12/21/2022]
Abstract
Stroke-induced cognitive impairments are of significant concern, however mechanisms that underpin these impairments remain poorly understood and researched. To further characterise cognitive impairments in our frontal cortex stroke model, and to align our assessments with what is used clinically, we tested young C57BL/6J mice trained in operant touchscreen chambers to complete the trial-unique nonmatched-to-location (TUNL) task. Based on baseline performance, animals were given either stroke (n = 12) or sham (n = 12) surgery using a photothrombosis model, bilaterally targeting the frontal cortex. Upon recovery, post-stroke spatial working memory was assessed by varying the degree of separation and delay within TUNL trials. Seven weeks after surgery, animals received a prelimbic injection of the retrograde tracer cholera toxin B (CTB) to access thalamo-PFC connectivity. Tissue was then processed histologically and immunohistochemically to assess infarct volume, astrogliosis and thalamocortical connectivity. Assessment of TUNL probes revealed sensitivity to a frontal cortex stroke (separation: p = 0.0003, delay: p < 0.0001), with stroke animals taking significantly longer (p = 0.0170) during reacquisition of the TUNL task, relative to shams. CTB-positive cell counts revealed a stroke-induced loss of thalamo-PFC connectivity. In addition, quantification of reactive astrogliosis revealed a positive correlation between the degree of astrogliosis expanding into white matter tracts and the development of cognitive impairments. This study reveals a stroke-induced impairment in mice completing the TUNL task. Our findings also demonstrate a significant loss of thalamo-PFC connections and a correlation between white matter reactive astrogliosis and cognitive impairment. Future experiments will investigate therapeutic interventions in the hope of promoting functional improvement in cognition.
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Affiliation(s)
- Josh Houlton
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin 9054, New Zealand
| | - Deanna Barwick
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin 9054, New Zealand
| | - Andrew N Clarkson
- Department of Anatomy, Brain Health Research Centre and Brain Research New Zealand, University of Otago, Dunedin 9054, New Zealand.
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8
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Sotelo MR, Kalinosky BT, Goodfriend K, Hyngstrom AS, Schmit BD. Indirect Structural Connectivity Identifies Changes in Brain Networks After Stroke. Brain Connect 2020; 10:399-410. [PMID: 32731752 DOI: 10.1089/brain.2019.0725] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Background/Purpose: The purpose of this study was (1) to identify changes in structural connectivity after stroke and (2) to relate changes in indirect connectivity to post-stroke impairment. Methods: A novel measure of indirect connectivity was implemented to assess the impact of stroke on brain connectivity. Probabilistic tractography was performed on 13 chronic stroke and 16 control participants to estimate connectivity between gray matter (GM) regions. The Fugl-Meyer assessment of motor impairment was measured for stroke participants. Network measures of direct and indirect connectivity were calculated, and these measures were linearly combined with measures of white matter integrity to predict motor impairment. Results: We found significantly reduced indirect connectivity in the frontal and parietal lobes, ipsilesional subcortical regions, and bilateral cerebellum after stroke. When added to the regression analysis, the volume of GM with reduced indirect connectivity significantly improved the correlation between image parameters and upper extremity motor impairment (R2 = 0.71, p < 0.05). Conclusion: This study provides evidence of changes in indirect connectivity in regions remote from the lesion, particularly in the cerebellum and regions in the fronto-parietal cortices, and these changes correlate with upper extremity motor impairment. These results highlight the value of using measures of indirect connectivity to identify the effect of stroke on brain networks. Impact statement Changes in indirect structural connectivity occur in regions distant from a lesion after stroke, highlighting the impact that stroke has on brain functional networks. Specifically, losses in indirect structural connectivity occur in hubs with high centrality, including the fronto-parietal cortices and cerebellum. These losses in indirect connectivity more accurately reflect motor impairments than measures of direct structural connectivity. As a consequence, indirect structural connectivity appears to be important to recovery after stroke and imaging biomarkers that incorporate indirect structural connectivity might improve prognostication of stroke outcomes.
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Affiliation(s)
- Miguel R Sotelo
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Benjamin T Kalinosky
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Karin Goodfriend
- Department of Physical Medicine and Rehabilitation, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Allison S Hyngstrom
- Department of Physical Therapy, Marquette University, Milwaukee, Wisconsin, USA
| | - Brian D Schmit
- Department of Biomedical Engineering, Marquette University and the Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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9
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Fury W, Park KW, Wu Z, Kim E, Woo MS, Bai Y, Macdonald LE, Croll SD, Cho S. Sustained Increases in Immune Transcripts and Immune Cell Trafficking During the Recovery of Experimental Brain Ischemia. Stroke 2020; 51:2514-2525. [PMID: 32640942 PMCID: PMC7815290 DOI: 10.1161/strokeaha.120.029440] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND AND PURPOSE Stroke is a major cause of chronic neurological disability. There is considerable interest in understanding how acute transcriptome changes evolve into subacute and chronic patterns that facilitate or limit spontaneous recovery. Here we mapped longitudinal changes in gene expression at multiple time points after stroke in mice out to 6 months. METHODS Adult C57BL/6 mice were subjected to transient middle cerebral artery occlusion. Longitudinal transcriptome levels were measured at 10 time points after stroke from acute to recovery phases of ischemic stroke. Localization and the number of mononuclear phagocytes were determined in the postischemic brain. Whole-mount brain imaging was performed in asplenic mice receiving GFP+ (green fluorescent protein)-tagged splenocytes. RESULTS Sustained stroke-induced mRNA abundance changes were observed in both hemispheres with 2989 ipsilateral and 822 contralateral genes significantly perturbed. In the hemisphere ipsilateral to the infarct, genes associated with immune functions were strongly affected, including temporally overlapping innate and adaptive immunity and macrophage M1 and M2 phenotype-related genes. The strong immune gene activation was accompanied by the sustained infiltration of peripheral immune cells at acute, subacute, and recovery stages of stroke. The infiltrated immune cells were found in the infarcted area but also in remote regions at 2 months after stroke. CONCLUSIONS The study identifies that immune components are the predominant molecular signatures and they may propagate or continuously respond to brain injury in the subacute to chronic phase after central nervous system injury. The study suggests a potential immune-based strategy to modify injury progression and tissue remodeling in ischemic stroke, even months after the initiating event.
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Affiliation(s)
- Wen Fury
- Regeneron Pharmaceuticals, Tarrytown, NY
| | - Keun Woo Park
- Burke Neurological Institute, White Plains, NY
- Feil Brain Mind Research Institute, Weill Cornell Medicine, New York, NY
| | - Zhuhao Wu
- Department of Cell, Developmental & Regenerative Biology and Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY
| | - Eunhee Kim
- Burke Neurological Institute, White Plains, NY
- Vivian L. Smith Department of Neurosurgery at University of Texas Health Science Center at Houston, Houston TX
| | | | - Yu Bai
- Regeneron Pharmaceuticals, Tarrytown, NY
| | | | | | - Sunghee Cho
- Burke Neurological Institute, White Plains, NY
- Feil Brain Mind Research Institute, Weill Cornell Medicine, New York, NY
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10
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Baudat C, Maréchal B, Corredor-Jerez R, Kober T, Meuli R, Hagmann P, Michel P, Maeder P, Dunet V. Automated MRI-based volumetry of basal ganglia and thalamus at the chronic phase of cortical stroke. Neuroradiology 2020; 62:1371-1380. [PMID: 32556424 PMCID: PMC7568697 DOI: 10.1007/s00234-020-02477-x] [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: 04/21/2020] [Accepted: 06/10/2020] [Indexed: 12/11/2022]
Abstract
Purpose We aimed at assessing the potential of automated MR morphometry to assess individual basal ganglia and thalamus volumetric changes at the chronic phase after cortical stroke. Methods Ninety-six patients (mean age: 65 ± 18 years, male 55) with cortical stroke at the chronic phase were retrospectively included. Patients were scanned at 1.5 T or 3 T using a T1-MPRAGE sequence. Resulting 3D images were processed with the MorphoBox prototype software to automatically segment basal ganglia and thalamus structures, and to obtain Z scores considering the confounding effects of age and sex. Stroke volume was estimated by manual delineation on T2-SE imaging. Z scores were compared between ipsi- and contralateral stroke side and according to the vascular territory. Potential relationship between Z scores and stroke volume was assessed using the Spearman correlation coefficient. Results Basal ganglia and thalamus volume Z scores were lower ipsilaterally to MCA territory stroke (p values < 0.034) while they were not different between ipsi- and contralateral stroke sides in non-MCA territory stroke (p values > 0.37). In MCA territory stroke, ipsilateral caudate nucleus (rho = − 0.34, p = 0.007), putamen (rho = − 0.50, p < 0.001), pallidum (rho = − 0.44, p < 0.001), and thalamus (rho = − 0.48, p < 0.001) volume Z scores negatively correlated with the cortical stroke volume. This relation was not influenced by cardiovascular risk factors or time since stroke. Conclusion Automated MR morphometry demonstrated atrophy of ipsilateral basal ganglia and thalamus at the chronic phase after cortical stroke in the MCA territory. The atrophy was related to stroke volume. These results confirm the potential role for automated MRI morphometry to assess remote changes after stroke.
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Affiliation(s)
- Cindy Baudat
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland
| | - Bénédicte Maréchal
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.,Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
| | - Ricardo Corredor-Jerez
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.,Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
| | - Tobias Kober
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.,Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland
| | - Reto Meuli
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland
| | - Patric Hagmann
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland
| | - Patrik Michel
- Stroke Center, Neurology Service, Department of Clinical Neurosciences, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Philippe Maeder
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland
| | - Vincent Dunet
- Department of Diagnostic and Interventional Radiology, Lausanne University Hospital and University of Lausanne, Rue du Bugnon 46, CH-1011, Lausanne, Switzerland.
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11
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Ermine CM, Somaa F, Wang TY, Kagan BJ, Parish CL, Thompson LH. Long-Term Motor Deficit and Diffuse Cortical Atrophy Following Focal Cortical Ischemia in Athymic Rats. Front Cell Neurosci 2019; 13:552. [PMID: 31920553 PMCID: PMC6927997 DOI: 10.3389/fncel.2019.00552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 11/29/2019] [Indexed: 12/24/2022] Open
Abstract
Development of new stroke therapies requires animal models that recapitulate the pathophysiological and functional consequences of ischemic brain damage over time-frames relevant to the therapeutic intervention. This is particularly relevant for the rapidly developing area of stem cell therapies, where functional replacement of circuitry will require maturation of transplanted human cells over months. An additional challenge is the establishment of models of ischemia with stable behavioral phenotypes in chronically immune-suppressed animals to allow for long-term survival of human cell grafts. Here we report that microinjection of endothelin-1 into the sensorimotor cortex of athymic rats results in ischemic damage with a sustained deficit in function of the contralateral forepaw that persists for up to 9 months. The histological post-mortem analysis revealed chronic and diffuse atrophy of the ischemic cortical hemisphere that continued to progress over 9 months. Secondary atrophy remote to the primary site of injury and its relationship with long-term cognitive and functional decline is now recognized in human populations. Thus, focal cortical infarction in athymic rats mirrors important pathophysiological and functional features relevant to human stroke, and will be valuable for assessing efficacy of stem cell based therapies.
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Affiliation(s)
- Charlotte M Ermine
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Fahad Somaa
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Ting-Yi Wang
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Brett J Kagan
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Clare L Parish
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
| | - Lachlan H Thompson
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia
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12
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Egorova N, Liem F, Hachinski V, Brodtmann A. Predicted Brain Age After Stroke. Front Aging Neurosci 2019; 11:348. [PMID: 31920628 PMCID: PMC6914736 DOI: 10.3389/fnagi.2019.00348] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 11/28/2019] [Indexed: 11/13/2022] Open
Abstract
Aging is a known non-modifiable risk factor for stroke. Usually, this refers to chronological rather than biological age. Biological brain age can be estimated based on cortical and subcortical brain measures. For stroke patients, it could serve as a more sensitive marker of brain health than chronological age. In this study, we investigated whether there is a difference in brain age between stroke survivors and control participants matched on chronological age. We estimated brain age at 3 months after stroke, and then followed the longitudinal trajectory over three time-points: within 6 weeks (baseline), at 3 and at 12 months following their clinical event. We found that brain age in stroke participants was higher compared to controls, with the mean difference between the groups varying between 3.9 and 8.7 years depending on the brain measure used for prediction. This difference in brain age was observed at 6 weeks after stroke and maintained at 3 and 12 months after stroke. The presence of group differences already at baseline suggests that stroke might be an ultimate manifestation of gradual cerebrovascular burden accumulation and brain degeneration. Brain age prediction, therefore, has the potential to be a useful biomarker for quantifying stroke risk.
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Affiliation(s)
- Natalia Egorova
- Division of Behavioural Neuroscience, The Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia.,Melbourne School of Psychological Sciences, University of Melbourne, Melbourne, VIC, Australia
| | - Franziskus Liem
- University Research Priority Program Dynamics of Healthy Aging, University of Zurich, Zurich, Switzerland
| | - Vladimir Hachinski
- Department of Clinical Neurological Sciences, Western University, London, ON, Canada.,Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, Western University, London, ON, Canada
| | - Amy Brodtmann
- Division of Behavioural Neuroscience, The Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia
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13
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Contralateral Brain Atrophy in Conservatively Treated Primary Intracerebral Hemorrhage. World Neurosurg 2019; 128:e391-e396. [PMID: 31029818 DOI: 10.1016/j.wneu.2019.04.160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 04/17/2019] [Accepted: 04/17/2019] [Indexed: 11/20/2022]
Abstract
BACKGROUND In patients with intracerebral hemorrhage (ICH), brain volume loss can occur in the hemisphere ipsilateral to the hematoma. However, contralateral hemispheric volume change after ICH is not well known. The present study aimed to investigate contralateral brain volume changes in patients with ICH who had not undergone surgery. METHODS Of the 2213 patients with ICH admitted to our hospital between January 2010 and December 2017, 46 patients without surgical intervention were included in the present study. We measured contralateral hemispheric brain volume in the axial images of brain computed tomography at the time of ICH onset and after 12 months. We analyzed the relationship between various factors and volume changes in the contralateral hemisphere. RESULTS The mean change percentage between the initial and follow-up contralateral parenchyma volume was 96.84%. The average volume decreased by 3.16% (P = 0.001). Univariate and multivariate logistic regression models revealed no significant factors associated with contralateral brain volume loss. Kruskal-Wallis test and Mann-Whitney U test showed no statistical significance (P = 0.824, P = 0.122) between ICH volume groups. CONCLUSIONS Contralateral parenchymal volumes were significantly decreased at follow-up brain computed tomography scanning; these changes may provide important clinical information on the remote effect of focal lesion and symptoms in the course of ICH treatment. However, further investigation is required to determine the mechanisms underlying these volume changes.
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14
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Haque ME, Gabr RE, Hasan KM, George S, Arevalo OD, Zha A, Alderman S, Jeevarajan J, Mas MF, Zhang X, Satani N, Friedman ER, Sitton CW, Savitz S. Ongoing Secondary Degeneration of the Limbic System in Patients With Ischemic Stroke: A Longitudinal MRI Study. Front Neurol 2019; 10:154. [PMID: 30890995 PMCID: PMC6411642 DOI: 10.3389/fneur.2019.00154] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 02/06/2019] [Indexed: 01/08/2023] Open
Abstract
Purpose: Ongoing post-stroke structural degeneration and neuronal loss preceding neuropsychological symptoms such as cognitive decline and depression are poorly understood. Various substructures of the limbic system have been linked to cognitive impairment. In this longitudinal study, we investigated the post-stroke macro- and micro-structural integrity of the limbic system using structural and diffusion tensor magnetic resonance imaging. Materials and Methods: Nineteen ischemic stroke patients (11 men, 8 women, average age 53.4 ± 12.3, range 18–75 years), with lesions remote from the limbic system, were serially imaged three times over 1 year. Structural and diffusion-tensor images (DTI) were obtained on a 3.0 T MRI system. The cortical thickness, subcortical volume, mean diffusivity (MD), and fractional anisotropy (FA) were measured in eight different regions of the limbic system. The National Institutes of Health Stroke Scale (NIHSS) was used for clinical assessment. A mixed model for multiple factors was used for statistical analysis, and p-values <0.05 was considered significant. Results: All patients demonstrated improved NIHSS values over time. The ipsilesional subcortical volumes of the thalamus, hippocampus, and amygdala significantly decreased (p < 0.05) and MD significantly increased (p < 0.05). The ipsilesional cortical thickness of the entorhinal and perirhinal cortices was significantly smaller than the contralesional hemisphere at 12 months (p < 0.05). The cortical thickness of the cingulate gyrus at 12 months was significantly decreased at the caudal and isthmus regions as compared to the 1 month assessment (p < 0.05). The cingulum fibers had elevated MD at the ipsilesional caudal-anterior and posterior regions compared to the corresponding contralesional regions. Conclusion: Despite the decreasing NIHSS scores, we found ongoing unilateral neuronal loss/secondary degeneration in the limbic system, irrespective of the lesion location. These results suggest a possible anatomical basis for post stroke psychiatric complications.
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Affiliation(s)
- Muhammad E Haque
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Refaat E Gabr
- Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Khader M Hasan
- Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Sarah George
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Octavio D Arevalo
- Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Alicia Zha
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Susan Alderman
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Jerome Jeevarajan
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Manual F Mas
- TIRR Memorial Hermann Rehabilitation and Research, Houston, TX, United States
| | - Xu Zhang
- Biostatistics/Epidemiology/Research Design Component, Center for Clinical and Translational Sciences, McGovern Medical School at University of Texas Health Science Center at Houston (UTHealth), Houston, TX, United States
| | - Nikunj Satani
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Elliott R Friedman
- Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Clark W Sitton
- Diagnostic and Interventional Imaging, University of Texas Health Science Center at Houston, Houston, TX, United States
| | - Sean Savitz
- Institute for Stroke and Cerebrovascular Diseases, University of Texas Health Science Center at Houston, Houston, TX, United States
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15
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Visser MM, Yassi N, Campbell BCV, Desmond PM, Davis SM, Spratt N, Parsons M, Bivard A. White Matter Degeneration after Ischemic Stroke: A Longitudinal Diffusion Tensor Imaging Study. J Neuroimaging 2018; 29:111-118. [PMID: 30160814 DOI: 10.1111/jon.12556] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 07/29/2018] [Accepted: 08/16/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Degeneration of gray matter and subcortical structures after ischemic stroke has been well described. However, little is known about white matter degeneration after stroke. It is unclear whether white matter degeneration occurs throughout the whole brain, or whether patterns of degeneration occur more in specific brain areas. METHODS We prospectively collected National Institutes of Health Stroke Scale (NIHSS) scores and diffusion tensor imaging (DTI) in patients with acute ischemic stroke within the first week after onset (baseline), and at 1 and 3 months. DTI was processed to produce maps of fractional anisotropy, apparent diffusion coefficients, and axial and radial diffusivity. DTI parameters in specified regions-of-interest corresponding to items on the NIHSS were calculated and changes over time were assessed using linear mixed-effect modeling. RESULTS Seventeen patients were included in the study. Mean age (SD) was 71 (11.7) years, and median (IQR) baseline NIHSS 9 (5-13.3). Changes over time were observed in both visual cortices, contralesional primary motor cortex, premotor cortex, and superior temporal gyrus (P < .05). Changes in the ipsilesional motor cortex and inferior parietal lobule were only seen in patients with scores on the respective NIHSS-items (P < .05). No significant changes in global white matter diffusivity parameters were identified (P > .05). CONCLUSION White matter changes after stroke may be localized rather than a global phenomenon.
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Affiliation(s)
- Milanka M Visser
- School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia.,Priority Research Centre for Stroke and Brain Injury, Hunter Medical Research Institute, Newcastle, New South Wales, Australia
| | - Nawaf Yassi
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Neurology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Bruce C V Campbell
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Neurology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Patricia M Desmond
- Department of Radiology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Melbourne Brain Centre, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Stephen M Davis
- Melbourne Brain Centre, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia
| | - Neil Spratt
- Priority Research Centre for Stroke and Brain Injury, Hunter Medical Research Institute, Newcastle, New South Wales, Australia.,Department of Neurology, John Hunter Hospital, University of Newcastle, Callaghan, New South Wales, Australia
| | - Mark Parsons
- Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Department of Neurology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Department of Neurology, John Hunter Hospital, University of Newcastle, Callaghan, New South Wales, Australia
| | - Andrew Bivard
- School of Medicine and Public Health, Faculty of Health and Medicine, University of Newcastle, Callaghan, New South Wales, Australia.,Department of Neurology, The Royal Melbourne Hospital, University of Melbourne, Melbourne, Victoria, Australia.,Department of Neurology, John Hunter Hospital, University of Newcastle, Callaghan, New South Wales, Australia
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16
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Bivard A, Lillicrap T, Maréchal B, Garcia-Esperon C, Holliday E, Krishnamurthy V, Levi CR, Parsons M. Transient Ischemic Attack Results in Delayed Brain Atrophy and Cognitive Decline. Stroke 2018; 49:384-390. [PMID: 29301970 DOI: 10.1161/strokeaha.117.019276] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 10/24/2017] [Accepted: 10/27/2017] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE Transient ischemic attack (TIA) initiates an ischemic cascade without resulting in frank infarction and, as such, represents a novel model to study the effects of this ischemic cascade and secondary neurodegeneration in humans. METHODS Patients with suspected TIA underwent acute brain perfusion imaging, and those with acute ischemia were enrolled into a prospective observational study. We collected baseline and 90-day magnetic resonance imaging, including MP-RAGE (high-resolution T1 sequence) and cognitive assessment with the Montreal Cognitive Assessment. Brain morphometry and within patient statistical analysis were performed to identify changes between baseline and 90-day imaging and clinical assessments. RESULTS Fifty patients with TIA with acute perfusion lesions were studied. All patients experienced a decrease in global cortical gray matter (P=0.005). Patients with anterior circulation TIA (n=31) also had a significant reduction in the volume of the pons (P<0.001), ipsilesional parietal lobe (P<0.001), occipital lobe (P=0.002), frontal lobe (P<0.001), temporal lobe (P=0.003), and thalamus (P=0.016). Patients with an anterior perfusion lesion on acute imaging also had a significant decrease in Montreal Cognitive Assessment between baseline and day 90 (P=0.027), which may be related to the volume of thalamic atrophy (R2=0.28; P=0.009). CONCLUSIONS In a prospective observational study, patients with TIA confirmed by acute perfusion imaging experienced a significant reduction in global gray matter and focal structural atrophy related to the area of acute ischemia. The atrophy also resulted in a proportional decreased cognitive performance on the Montreal Cognitive Assessment. Further studies are required to identify the mechanisms of this atrophy.
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Affiliation(s)
- Andrew Bivard
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.).
| | - Thomas Lillicrap
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
| | - Bénédicte Maréchal
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
| | - Carlos Garcia-Esperon
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
| | - Elizabeth Holliday
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
| | - Venkatesh Krishnamurthy
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
| | - Christopher R Levi
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
| | - Mark Parsons
- From the Department of Neurology, John Hunter Hospital (A.B., T.L., C.G.-E., V.K., C.R.L., M.P.) and Hunter Medical Research Institute (A.B., T.L., C.G.-E., E.H., V.K., C.R.L., M.P.), University of Newcastle, New South Wales, Australia; Advanced Clinical Imaging Technology, Siemens Healthcare HC CEMEA SUI DI PI, Lausanne, Switzerland (B.M.); Department of Radiology, CHUV, Lausanne, Switzerland (B.M.); and LTS5, EPFL, Lausanne, Switzerland (B.M.)
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17
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Browndyke JN, Berger M, Smith PJ, Harshbarger TB, Monge ZA, Panchal V, Bisanar TL, Glower DD, Alexander JH, Cabeza R, Welsh-Bohmer K, Newman MF, Mathew JP. Task-related changes in degree centrality and local coherence of the posterior cingulate cortex after major cardiac surgery in older adults. Hum Brain Mapp 2017; 39:985-1003. [PMID: 29164774 DOI: 10.1002/hbm.23898] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 10/24/2017] [Accepted: 11/13/2017] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Older adults often display postoperative cognitive decline (POCD) after surgery, yet it is unclear to what extent functional connectivity (FC) alterations may underlie these deficits. We examined for postoperative voxel-wise FC changes in response to increased working memory load demands in cardiac surgery patients and nonsurgical controls. EXPERIMENTAL DESIGN Older cardiac surgery patients (n = 25) completed a verbal N-back working memory task during MRI scanning and cognitive testing before and 6 weeks after surgery; nonsurgical controls with cardiac disease (n = 26) underwent these assessments at identical time intervals. We measured postoperative changes in degree centrality, the number of edges attached to a brain node, and local coherence, the temporal homogeneity of regional functional correlations, using voxel-wise graph theory-based FC metrics. Group × time differences were evaluated in these FC metrics associated with increased N-back working memory load (2-back > 1-back), using a two-stage partitioned variance, mixed ANCOVA. PRINCIPAL OBSERVATIONS Cardiac surgery patients demonstrated postoperative working memory load-related degree centrality increases in the left dorsal posterior cingulate cortex (dPCC; p < .001, cluster p-FWE < .05). The dPCC also showed a postoperative increase in working memory load-associated local coherence (p < .001, cluster p-FWE < .05). dPCC degree centrality and local coherence increases were inversely associated with global cognitive change in surgery patients (p < .01), but not in controls. CONCLUSIONS Cardiac surgery patients showed postoperative increases in working memory load-associated degree centrality and local coherence of the dPCC that were inversely associated with postoperative global cognitive outcomes and independent of perioperative cerebrovascular damage.
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Affiliation(s)
- Jeffrey N Browndyke
- Geriatric Behavioral Health Division, Department of Psychiatry & Behavioral Sciences, Duke University Health System, Durham, North Carolina.,Duke Institute for Brain Sciences, Duke University, Durham, North Carolina.,Duke Brain Imaging and Analysis Center, Duke University, Durham, North Carolina
| | - Miles Berger
- Division of Neuroanesthesiology, Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Patrick J Smith
- Behavioral Medicine Division, Department of Psychiatry & Behavioral Sciences, Duke University Medical Center, Durham, North Carolina
| | - Todd B Harshbarger
- Duke Brain Imaging and Analysis Center, Duke University, Durham, North Carolina.,Department of Radiology, Duke University Medical Center, Durham, North Carolina
| | - Zachary A Monge
- Center for Cognitive Neuroscience, Duke University, Durham, North Carolina
| | - Viral Panchal
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Tiffany L Bisanar
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Donald D Glower
- Cardiovascular & Thoracic Division, Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - John H Alexander
- Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina
| | - Roberto Cabeza
- Duke Institute for Brain Sciences, Duke University, Durham, North Carolina.,Duke Brain Imaging and Analysis Center, Duke University, Durham, North Carolina.,Center for Cognitive Neuroscience, Duke University, Durham, North Carolina
| | - Kathleen Welsh-Bohmer
- Geriatric Behavioral Health Division, Department of Psychiatry & Behavioral Sciences, Duke University Health System, Durham, North Carolina.,Department of Neurology, Duke University Medical Center, Durham, North Carolina
| | - Mark F Newman
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
| | - Joseph P Mathew
- Department of Anesthesiology, Duke University Medical Center, Durham, North Carolina
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18
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Kim JH, Kim YS, Kim SH, Kim SD, Park JY, Kim TS, Joo SP. Contralateral Hemispheric Brain Atrophy After Primary Intracerebral Hemorrhage. World Neurosurg 2017; 102:56-64. [DOI: 10.1016/j.wneu.2017.02.105] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/20/2017] [Accepted: 02/21/2017] [Indexed: 12/18/2022]
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19
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Sensorimotor Cortical Neuroplasticity in the Early Stage of Bell's Palsy. Neural Plast 2017; 2017:8796239. [PMID: 28299208 PMCID: PMC5337373 DOI: 10.1155/2017/8796239] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2016] [Revised: 12/22/2016] [Accepted: 01/05/2017] [Indexed: 12/26/2022] Open
Abstract
Neuroplasticity is a common phenomenon in the human brain following nerve injury. It is defined as the brain's ability to reorganize by creating new neural pathways in order to adapt to change. Here, we use task-related and resting-state fMRI to investigate neuroplasticity in the primary sensory (S1) and motor cortex (M1) in patients with acute Bell's palsy (BP). We found that the period directly following the onset of BP (less than 14 days) is associated with significant decreases in regional homogeneity (ReHo), fractional amplitude of low frequency fluctuations (fALFF), and intrinsic connectivity contrast (ICC) values in the contralateral S1/M1 and in ReHo and ICC values in the ipsilateral S1/M1, compared to healthy controls. The regions with decreased ReHo, fALFF, and ICC values were in both the face and hand region of S1/M1 as indicated by resting-state fMRI but not task-related fMRI. Our results suggest that the early stages of BP are associated with functional neuroplasticity in both the face and hand regions of S1/M1 and that resting-state functional fMRI may be a sensitive tool to detect these early stages of plasticity in patient populations.
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20
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Ruan L, Wang Y, Chen SC, Zhao T, Huang Q, Hu ZL, Xia NZ, Liu JJ, Chen WJ, Zhang Y, Cheng JL, Gao HC, Yang YJ, Sun HZ. Metabolite changes in the ipsilateral and contralateral cerebral hemispheres in rats with middle cerebral artery occlusion. Neural Regen Res 2017; 12:931-937. [PMID: 28761426 PMCID: PMC5514868 DOI: 10.4103/1673-5374.208575] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cerebral ischemia not only causes pathological changes in the ischemic areas but also induces a series of secondary changes in more distal brain regions (such as the contralateral cerebral hemisphere). The impact of supratentorial lesions, which are the most common type of lesion, on the contralateral cerebellum has been studied in patients by positron emission tomography, single photon emission computed tomography, magnetic resonance imaging and diffusion tensor imaging. In the present study, we investigated metabolite changes in the contralateral cerebral hemisphere after supratentorial unilateral ischemia using nuclear magnetic resonance spectroscopy-based metabonomics. The permanent middle cerebral artery occlusion model of ischemic stroke was established in rats. Rats were randomly divided into the middle cerebral artery occlusion 1-, 3-, 9- and 24-hour groups and the sham group. 1H nuclear magnetic resonance spectroscopy was used to detect metabolites in the left and right cerebral hemispheres. Compared with the sham group, the concentrations of lactate, alanine, γ-aminobutyric acid, choline and glycine in the ischemic cerebral hemisphere were increased in the acute stage, while the concentrations of N-acetyl aspartate, creatinine, glutamate and aspartate were decreased. This demonstrates that there is an upregulation of anaerobic glycolysis (shown by the increase in lactate), a perturbation of choline metabolism (suggested by the increase in choline), neuronal cell damage (shown by the decrease in N-acetyl aspartate) and neurotransmitter imbalance (evidenced by the increase in γ-aminobutyric acid and glycine and by the decrease in glutamate and aspartate) in the acute stage of cerebral ischemia. In the contralateral hemisphere, the concentrations of lactate, alanine, glycine, choline and aspartate were increased, while the concentrations of γ-aminobutyric acid, glutamate and creatinine were decreased. This suggests that there is a difference in the metabolite changes induced by ischemic injury in the contralateral and ipsilateral cerebral hemispheres. Our findings demonstrate the presence of characteristic changes in metabolites in the contralateral hemisphere and suggest that they are most likely caused by metabolic changes in the ischemic hemisphere.
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Affiliation(s)
- Lei Ruan
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yan Wang
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Shu-Chao Chen
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Tian Zhao
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Qun Huang
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Zi-Long Hu
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Neng-Zhi Xia
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Jin-Jin Liu
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Wei-Jian Chen
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yong Zhang
- Department of Radiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, China
| | - Jing-Liang Cheng
- Department of Radiology, First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan Province, China
| | - Hong-Chang Gao
- School of Pharmacy, Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Yun-Jun Yang
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
| | - Hou-Zhang Sun
- Department of Radiology, First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, China
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Yassi N, Desmond PM, Masters CL. Magnetic Resonance Imaging of Vascular Contributions to Cognitive Impairment and Dementia. J Mol Neurosci 2016; 60:349-353. [DOI: 10.1007/s12031-016-0799-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2016] [Accepted: 07/07/2016] [Indexed: 02/06/2023]
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22
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Zuo X, Hou Q, Jin J, Zhan L, Li X, Sun W, Lin K, Xu E. Inhibition of Cathepsin B Alleviates Secondary Degeneration in Ipsilateral Thalamus After Focal Cerebral Infarction in Adult Rats. J Neuropathol Exp Neurol 2016; 75:816-26. [PMID: 27371711 DOI: 10.1093/jnen/nlw054] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Secondary degeneration in areas beyond ischemic foci can inhibit poststroke recovery. The cysteine protease Cathepsin B (CathB) regulates cell death and intracellular protein catabolism. To investigate the roles of CathB in the development of secondary degeneration in the ventroposterior nucleus (VPN) of the ipsilateral thalamus after focal cerebral infarction, infarct volumes, immunohistochemistry and immunofluorescence, and Western blotting analyses were conducted in a distal middle cerebral artery occlusion (dMCAO) stroke model in adult rats. We observed marked neuron loss and gliosis in the ipsilateral thalamus after dMCAO, and the expression of CathB and cleaved caspase-3 in the VPN was significantly upregulated; glial cells were the major source of CathB. Although it had no effect on infarct volume, delayed intracerebroventricular treatment with the membrane-permeable CathB inhibitor CA-074Me suppressed the expression of CathB and cleaved caspase-3 in ipsilateral VPN and accordingly alleviated the secondary degeneration. These data indicate that CathB mediates a novel mechanism of secondary degeneration in the VPN of the ipsilateral thalamus after focal cortical infarction and suggest that CathB might be a therapeutic target for the prevention of secondary degeneration in patients after stroke.
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Affiliation(s)
- Xialin Zuo
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - Qinghua Hou
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - Jizi Jin
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - Lixuan Zhan
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - Xinyu Li
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - Weiwen Sun
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - Kunqin Lin
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH)
| | - En Xu
- Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Institute of Neurosciences and the Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, China (XZ, QH, JJ, LZ, XL, WS, KL, EX); and Department of Neurology, Provincial People's Hospital, Guangdong No.2, Guangzhou, China (QH).
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23
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Weishaupt N, Zhang A, Deziel RA, Tasker RA, Whitehead SN. Prefrontal Ischemia in the Rat Leads to Secondary Damage and Inflammation in Remote Gray and White Matter Regions. Front Neurosci 2016; 10:81. [PMID: 26973455 PMCID: PMC4773446 DOI: 10.3389/fnins.2016.00081] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2016] [Accepted: 02/18/2016] [Indexed: 12/31/2022] Open
Abstract
Secondary damage processes, such as inflammation and oxidative stress, can exacerbate an ischemic lesion and spread to adjacent brain regions. Yet, few studies investigate how regions remote from the infarct could also suffer from degeneration and inflammation in the aftermath of a stroke. To find out to what extent far-remote brain regions are affected after stroke, we used a bilateral endothelin-1-induced prefrontal infarct rat model. Brain regions posterior to the prefrontal cortical infarct were analyzed for ongoing neurodegeneration using FluoroJadeB (FJB) and for neuroinflammation using Iba1 and OX-6 immunohistochemistry 28 days post-stroke. The FJB-positive dorsomedial nucleus of the thalamus (DMN) and retrosplenial area (RSA) of the cortex displayed substantial neuroinflammation. Significant neuronal loss was only observed within the cortex. Significant microglia recruitment and activation in the FJB-positive internal capsule indicates remote white matter pathology. These findings demonstrate that even regions far remote from an infarct are affected predictably based on anatomical connectivity, and that white matter inflammation is an integral part of remote pathology. The delayed nature of this pathology makes it a valid target for preventative treatment, potentially with an extended time window of opportunity for therapeutic intervention using anti-inflammatory agents.
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Affiliation(s)
- Nina Weishaupt
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario London, ON, Canada
| | - Angela Zhang
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario London, ON, Canada
| | - Robert A Deziel
- Department of Biomedical Sciences, University of Prince Edward Island Charlottetown, PEI, Canada
| | - R Andrew Tasker
- Department of Biomedical Sciences, University of Prince Edward Island Charlottetown, PEI, Canada
| | - Shawn N Whitehead
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario London, ON, Canada
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Zhou LY, Wright TE, Clarkson AN. Prefrontal cortex stroke induces delayed impairment in spatial memory. Behav Brain Res 2016; 296:373-378. [DOI: 10.1016/j.bbr.2015.08.022] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/07/2015] [Accepted: 08/18/2015] [Indexed: 11/26/2022]
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25
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Association between baseline peri-infarct magnetic resonance spectroscopy and regional white matter atrophy after stroke. Neuroradiology 2015; 58:3-10. [DOI: 10.1007/s00234-015-1593-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/04/2015] [Indexed: 11/26/2022]
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