1
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Mulder IA, Abbinanti M, Woller SA, Ruschel J, Coutinho JM, de Vries HE, van Bavel E, Rosen K, McKerracher L, Ayata C. The novel ROCK2 selective inhibitor NRL-1049 preserves the blood-brain barrier after acute injury. J Cereb Blood Flow Metab 2024:271678X241238845. [PMID: 38833563 DOI: 10.1177/0271678x241238845] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/06/2024]
Abstract
Endothelial blood-brain barrier (BBB) dysfunction is critical in the pathophysiology of brain injury. Rho-associated protein kinase (ROCK) activation disrupts BBB integrity in the injured brain. We aimed to test the efficacy of a novel ROCK2 inhibitor in preserving the BBB after acute brain injury. We characterized the molecular structure and pharmacodynamic and pharmacokinetic properties of a novel selective ROCK2 inhibitor, NRL-1049, and its first metabolite, 1-hydroxy-NRL-1049 (referred to as NRL-2017 hereon) and tested the efficacy of NRL-1049 on the BBB integrity in rodent models of acute brain injury. Our data show that NRL-1049 and NRL-2017 both inhibit ROCK activity and are 44-fold and 17-fold more selective towards ROCK2 than ROCK1, respectively. When tested in a mouse model of cortical cryoinjury, NRL-1049 significantly attenuated the increase in water content. Interestingly, 60% of the mice in the vehicle arm developed seizures within 2 hours after cryoinjury versus none in the NRL-1049 arm. In spontaneously hypertensive rats, NRL-1049 attenuated the dramatic surge in Evans Blue extravasation compared with the vehicle arm after transient middle cerebral artery occlusion. Hemorrhagic transformation was also reduced. We show that NRL-1049, a selective ROCK2 inhibitor, is a promising drug candidate to preserve the BBB after brain injury.
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Affiliation(s)
- Inge A Mulder
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Department of Biomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, Amsterdam, the Netherlands
- Amsterdam Neurosciences, Neurovascular Disorders, Amsterdam, the Netherlands
| | | | | | | | - Jonathan M Coutinho
- Amsterdam Neurosciences, Neurovascular Disorders, Amsterdam, the Netherlands
- Department of Neurology, Amsterdam UMC location University of Amsterdam, Amsterdam, the Netherlands
| | - Helga E de Vries
- Amsterdam Neurosciences, Neurovascular Disorders, Amsterdam, the Netherlands
- Department of Molecular Cell Biology and Immunology, Amsterdam UMC location Vrije Universiteit, Amsterdam, the Netherlands
| | - Ed van Bavel
- Department of Biomedical Engineering and Physics, Amsterdam UMC location University of Amsterdam, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Microcirculation, Amsterdam, the Netherlands
- Amsterdam Neurosciences, Neurovascular Disorders, Amsterdam, the Netherlands
| | | | - Lisa McKerracher
- BioAxone BioSciences Inc, Boston, MA, USA
- Department of Neurology and Neurosurgery, McGill University, Montreal, Quebec, Canada
| | - Cenk Ayata
- Neurovascular Research Unit, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
- Stroke Service, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts, USA
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2
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Sri Hari A, Metcalf CS. The "Curious Case of Postictal Oxygen Dissipation": Could ROS Be the Culprit? Epilepsy Curr 2024; 24:59-61. [PMID: 38327542 PMCID: PMC10846519 DOI: 10.1177/15357597231216921] [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] [Indexed: 02/09/2024] Open
Abstract
Postictal Hypoxia Involves Reactive Oxygen Species and Is Ameliorated by Chronic Mitochondrial Uncoupling Villa BR, George AG, Shutt TE, Sullivan PG, Rho JM, Teskey GC. Neuropharmacology . 2023;238:109653. doi:10.1016/j.neuropharm.2023.109653 Prolonged severe hypoxia follows brief seizures and represents a mechanism underlying several negative postictal manifestations without interventions. Approximately 50% of the postictal hypoxia phenomenon can be accounted for by arteriole vasoconstriction. What accounts for the rest of the drop in unbound oxygen is unclear. Here, we determined the effect of pharmacological modulation of mitochondrial function on tissue oxygenation in the hippocampus of rats after repeatedly evoked seizures. Rats were treated with mitochondrial uncoupler 2,4 dinitrophenol (DNP) or antioxidants. Oxygen profiles were recorded using a chronically implanted oxygen-sensing probe, before, during, and after seizure induction. Mitochondrial function and redox tone were measured using in vitro mitochondrial assays and immunohistochemistry. Postictal cognitive impairment was assessed using the novel object recognition task. Mild mitochondrial uncoupling by DNP raised hippocampal oxygen tension and ameliorated postictal hypoxia. Chronic DNP also lowered mitochondrial oxygen-derived reactive species and oxidative stress in the hippocampus during postictal hypoxia. Uncoupling the mitochondria exerts therapeutic benefits on postictal cognitive dysfunction. Finally, antioxidants do not affect postictal hypoxia, but protect the brain from associated cognitive deficits. We provided evidence for a metabolic component of the prolonged oxygen deprivation that follow seizures and its pathological sequelae. Furthermore, we identified a molecular underpinning of this metabolic component, which involves excessive oxygen conversion into reactive species. Mild mitochondrial uncoupling may be a potential therapeutic strategy to treat the postictal state where seizure control is absent or poor.
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3
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Lee JM, Han I, Nam KH, Kim DH, Song S, Park H, Kim H, Kim M, Choi J, Lee JI. Preclinical mouse model of optical coherence tomography for subcortical brain imaging without dissection. JOURNAL OF BIOPHOTONICS 2021; 14:e202100143. [PMID: 34346171 DOI: 10.1002/jbio.202100143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 07/23/2021] [Accepted: 07/26/2021] [Indexed: 06/13/2023]
Abstract
The purpose of this study was to investigate the feasibility of using optical coherence tomography (OCT) to identify internal brain lesions, specifically intracerebral hemorrhage, without dissection. Mice with artificially injected brain hematomas were used to test the OCT system, and the recorded images were compared with microscopic images of the same mouse brains after hematoxylin and eosin staining. The intracranial structures surrounding the hematomas were clearly visualized by the OCT system without dissection. These images reflect the ability of OCT to determine the extent of a lesion in several planes. OCT is a useful technology, and these findings could be used as a starting point for future research in intraoperative imaging.
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Affiliation(s)
- Jae Meen Lee
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Inho Han
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Kyoung Hyup Nam
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Dong Hwan Kim
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Seunghwan Song
- Department of Thoracic and Cardiovascular Surgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Heejeong Park
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
| | - Hongki Kim
- Kohyoung Technology, Inc, Seoul, South Korea
| | - Minkyu Kim
- Kohyoung Technology, Inc, Seoul, South Korea
| | | | - Jae Il Lee
- Department of Neurosurgery, Medical Research Institute, Pusan National University Hospital, Busan, South Korea
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4
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Liu H, Tufa U, Zahra A, Chow J, Sivanenthiran N, Cheng C, Liu Y, Cheung P, Lim S, Jin Y, Mao M, Sun Y, Wu C, Wennberg R, Bardakjian B, Carlen PL, Eubanks JH, Song H, Zhang L. Electrographic Features of Spontaneous Recurrent Seizures in a Mouse Model of Extended Hippocampal Kindling. Cereb Cortex Commun 2021; 2:tgab004. [PMID: 34296153 PMCID: PMC8152854 DOI: 10.1093/texcom/tgab004] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 01/08/2021] [Accepted: 01/13/2021] [Indexed: 01/14/2023] Open
Abstract
Epilepsy is a chronic neurological disorder characterized by spontaneous recurrent seizures (SRS) and comorbidities. Kindling through repetitive brief stimulation of a limbic structure is a commonly used model of temporal lobe epilepsy. Particularly, extended kindling over a period up to a few months can induce SRS, which may simulate slowly evolving epileptogenesis of temporal lobe epilepsy. Currently, electroencephalographic (EEG) features of SRS in rodent models of extended kindling remain to be detailed. We explored this using a mouse model of extended hippocampal kindling. Intracranial EEG recordings were made from the kindled hippocampus and unstimulated hippocampal, neocortical, piriform, entorhinal, or thalamic area in individual mice. Spontaneous EEG discharges with concurrent low-voltage fast onsets were observed from the two corresponding areas in nearly all SRS detected, irrespective of associated motor seizures. Examined in brain slices, epileptiform discharges were induced by alkaline artificial cerebrospinal fluid in the hippocampal CA3, piriform and entorhinal cortical areas of extended kindled mice but not control mice. Together, these in vivo and in vitro observations suggest that the epileptic activity involving a macroscopic network may generate concurrent discharges in forebrain areas and initiate SRS in hippocampally kindled mice.
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Affiliation(s)
- Haiyu Liu
- Departments of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021 China.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Uilki Tufa
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3H5, Canada
| | - Anya Zahra
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Jonathan Chow
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Nila Sivanenthiran
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Chloe Cheng
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yapg Liu
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Phinehas Cheung
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yaozhong Jin
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Min Mao
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Yuqing Sun
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Richard Wennberg
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada
| | - Berj Bardakjian
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3H5, Canada
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada
| | - James H Eubanks
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Surgery, University of Toronto, Toronto, Ontario M5G 1X5, Canada
| | - Hongmei Song
- Departments of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin 130021 China.,Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, Ontario, Canada M5T 2S8.,Department of Medicine, University of Toronto, Toronto, Ontario M2K 1E2, Canada
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5
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Ma K, Bin NR, Shi S, Harada H, Wada Y, Wada GHS, Monnier PP, Sugita S, Zhang L. Observations From a Mouse Model of Forebrain Voa1 Knockout: Focus on Hippocampal Structure and Function. Front Cell Neurosci 2019; 13:484. [PMID: 31824264 PMCID: PMC6881385 DOI: 10.3389/fncel.2019.00484] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Accepted: 10/11/2019] [Indexed: 12/22/2022] Open
Abstract
Voa protein is a subunit of V-ATPase proton pump which is essential to acidify intracellular organelles including synaptic vesicles. Voa1 is one of the four isoforms of Voa family with strong expression in neurons. Our present study was aimed to examine the role of Voa1 protein in mammalian brain neurons. To circumvent embryonic lethality, we generated conditional Voa1 knockout mice in which Voa1 was selectively deleted from forebrain pyramidal neurons. We performed experiments in the Voa1 knockout mice of ages 5-6 months to assess the persistent effects of Voa1 deletion. We found that the Voa1 knockout mice exhibited poor performance in the Morris water maze test compared to control mice. In addition, synaptic field potentials of the hippocampal CA1 region were greatly diminished in the Voa1 knockout mice when examined in brain slices in vitro. Furthermore, brain histological experiments showed severe degeneration of dorsal hippocampal CA1 neurons while CA3 neurons were largely preserved. The CA1 neurodegeneration was associated with general brain atrophy as overall hemispheric areas were reduced in the Voa1 cKO mice. Despite the CA1 degeneration and dysfunction, electroencephalographic recordings from the hippocampal CA3 area revealed aberrant spikes and non-convulsive discharges in the Voa1 knockout mice but not in control mice. These hippocampal spikes were suppressed by single intra-peritoneal injection of diazepam which is a benzodiazepine GABAA receptor enhancer. Together these results suggest that Voa1 related activities are essential for the survival of the targeted neurons in the dorsal hippocampal CA1 as well as other forebrain areas. We postulate that the Voa1 knockout mice may serve as a valuable model for further investigation of V-ATPase dysfunction related neuronal degeneration and functional abnormalities in forebrain areas particularly the hippocampus.
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Affiliation(s)
- Ke Ma
- Department of Pediatric Outpatient, The First Hospital of Jilin University, Jilin, China.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Na-Ryum Bin
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Shan Shi
- Department of Pediatric Outpatient, The First Hospital of Jilin University, Jilin, China.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Hidekiyo Harada
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Yoh Wada
- Division of Biological Science, Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan
| | - Ge-Hong-Sun Wada
- Department of Biochemistry, Faculty of Pharmaceutical Sciences, Doshisha Women's College, Kyoto, Japan
| | - Philippe P Monnier
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Ophthalmology, University of Toronto, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Shuzo Sugita
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Medicine, University of Toronto, Toronto, ON, Canada
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6
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Zhang W, Wang L, Pang X, Zhang J, Guan Y. Role of microRNA-155 in modifying neuroinflammation and γ-aminobutyric acid transporters in specific central regions after post-ischaemic seizures. J Cell Mol Med 2019; 23:5017-5024. [PMID: 31144434 PMCID: PMC6653087 DOI: 10.1111/jcmm.14358] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 03/14/2019] [Accepted: 04/14/2019] [Indexed: 12/16/2022] Open
Abstract
In the central nervous system, interleukin (IL)‐1β, IL‐6 and tumour necrosis factor (TNF)‐α have a regulatory role in pathophysiological processes of epilepsy. In addition, γ‐aminobutyric acid (GABA) transporter type 1 and type 3 (GAT‐1 and GAT‐3) modulate the levels of extracellular GABA in involvement in the neuroinflammation on epileptogenesis. Thus, in the current report we examined the effects of inhibiting microRNA‐155 (miR‐155) on the levels of IL‐1β, IL‐6 and TNF‐α, and expression of GAT‐1 and GAT‐3 in the parietal cortex, hippocampus and amygdala of rats with nonconvulsive seizure (NCS) following cerebral ischaemia. Real time RT‐PCR, ELISA and Western blot analysis were used to examine the miR‐155, proinflammatory cytokines (PICs) and GAT‐1/GAT‐3 respectively. With induction of NCS, the levels of miR‐155 were amplified in the parietal cortex, hippocampus and amygdala and this was accompanied with increases of IL‐1β, IL‐6 and TNF‐α. In those central areas, expression of GAT‐1 and GAT‐3 was upregulated; and GABA was reduced in rats following NCS. Intracerebroventricular infusion of miR‐155 inhibitor attenuated the elevation of PICs, amplification of GAT‐1 and GAT‐3 and impairment of GABA. Furthermore, inhibition of miR‐155 decreased the number of NCS events following cerebral ischaemia. Inhibition of miR‐155 further improved post‐ischaemia‐evoked NCS by altering neuroinflammation‐GABA signal pathways in the parietal cortex, hippocampus and amygdala. Results suggest the role of miR‐155 in regulating post‐ischaemic seizures via PICs‐GABA mechanisms.
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Affiliation(s)
- Wenwen Zhang
- Department of Anesthesiology, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Luping Wang
- Department of Anesthesiology, School and Hospital of Stomatology, Jilin University, Changchun, Jilin, China
| | - Xiaochuan Pang
- Clinical Laboratory, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Jian Zhang
- Department of Anesthesiology, The First Hospital of Jilin University, Changchun, Jilin, China
| | - Yi Guan
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, Jilin, China
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7
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Dunbar M, Shah H, Shinde S, Vayalumkal J, Vanderkooi OG, Wei XC, Kirton A. Stroke in Pediatric Bacterial Meningitis: Population-Based Epidemiology. Pediatr Neurol 2018; 89:11-18. [PMID: 30392967 DOI: 10.1016/j.pediatrneurol.2018.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 09/05/2018] [Accepted: 09/13/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Bacterial meningitis is a severe infection of the nervous system with a high complication rate including stroke. The purpose of this study is to assess the incidence, risk factors, patterns, and outcomes in pediatric meningitis complicated by stroke. METHODS The study design was a population-based, 10-year retrospective (2002 to 2012) cohort study set in Southern Alberta, Canada. The inclusion criteria were: (1) age from newborn to 18 years, (2) brain magnetic resonance imaging (MRI) including diffusion-weighted imaging during admission, and (3) laboratory confirmed acute bacterial meningitis. The main outcomes were demographics, clinical presentations, risk factors, laboratory findings, radiographic findings, and neurological outcomes. FINDINGS Forty-three patients had confirmed bacterial meningitis and diffusion MRI (9 neonates (21%), 89% male; 22 infants aged one month to one year (51%), 50% male; and 12 children older than one year (28%), 58% male, median age four years (interquartile range 7.9 years). Ischemic stroke was confirmed in 16/43 (37%), often multifocal (94%). Patients with stroke were significantly more likely to have seizures (P = 0.025), otitis media (P = 0.029), and multiple presentations to hospital (P = 0.013). Mortality was 25% in children with stroke compared with 4% in those without (P = 0.067). Survivors with stroke were more likely to have neurological deficits at follow-up (69% versus 26%, P = 0.019). CONCLUSIONS More than one-third of children with acute bacterial meningitis and clinically indicated MRI had ischemic stroke. Stroke was associated with clinical factors including duration of illness, seizures, and causative organisms. Stroke was associated with higher mortality and morbidity, warranting consideration of increased MRI screening and new approaches to treatment.
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Affiliation(s)
- Mary Dunbar
- Department of Community Health Services, University of Calgary, Calgary, Alberta, Canada; Calgary Pediatric Stroke Program, University of Calgary, Calgary, Alberta, Canada
| | - Hely Shah
- Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Siddharth Shinde
- Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Joseph Vayalumkal
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada
| | - Otto G Vanderkooi
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada
| | - Xing-Chang Wei
- Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Adam Kirton
- Department of Pediatrics, University of Calgary, Calgary, Alberta, Canada; Department of Clinical Neuroscience, University of Calgary, Calgary, Alberta, Canada; Department of Radiology, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada; Department of Community Health Services, University of Calgary, Calgary, Alberta, Canada; Alberta Children's Hospital Research Institute, Calgary, Alberta, Canada; Hotchkiss Brain Institute, Calgary, Alberta, Canada; Calgary Pediatric Stroke Program, University of Calgary, Calgary, Alberta, Canada.
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8
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Song H, Mylvaganam SM, Wang J, Mylvaganam SMK, Wu C, Carlen PL, Eubanks JH, Feng J, Zhang L. Contributions of the Hippocampal CA3 Circuitry to Acute Seizures and Hyperexcitability Responses in Mouse Models of Brain Ischemia. Front Cell Neurosci 2018; 12:278. [PMID: 30210302 PMCID: PMC6123792 DOI: 10.3389/fncel.2018.00278] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Accepted: 08/08/2018] [Indexed: 12/29/2022] Open
Abstract
The hippocampal circuitry is widely recognized as susceptible to ischemic injury and seizure generation. However, hippocampal contribution to acute non-convulsive seizures (NCS) in models involving middle cerebral artery occlusion (MCAO) remains to be determined. To address this, we occluded the middle cerebral artery in adult C57 black mice and monitored electroencephalographic (EEG) discharges from hippocampal and neocortical areas. Electrographic discharges in the absence of convulsive motor behaviors were observed within 90 min following occlusion of the middle cerebral artery. Hippocampal discharges were more robust than corresponding cortical discharges in all seizure events examined, and hippocampal discharges alone or with minimal cortical involvement were also observed in some seizure events. Seizure development was associated with ipsilateral hippocampal injuries as determined by subsequent histological examinations. We also introduced hypoxia-hypoglycemia episodes in mouse brain slices and examined regional hyperexcitable responses ex vivo. Extracellular recordings showed that the hippocampal CA3 region had a greater propensity for exhibiting single/multiunit activities or epileptiform field potentials following hypoxic-hypoglycemic (HH) episodes compared to the CA1, dentate gyrus, entorhinal cortical (EC) or neocortical regions. Whole-cell recordings revealed that CA3 pyramidal neurons exhibited excessive excitatory postsynaptic currents, attenuated inhibitory postsynaptic currents and intermittent or repetitive spikes in response to HH challenge. Together, these observations suggest that hippocampal discharges, possibly as a result of CA3 circuitry hyperexcitability, are a major component of acute NCS in a mouse model of MCAO.
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Affiliation(s)
- Hongmei Song
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China
| | | | - Justin Wang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | | | - Chiping Wu
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Peter L. Carlen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - James H. Eubanks
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, ON, Canada
| | - Jiachun Feng
- Department of Neurology, The First Hospital of Jilin University, Changchun, China
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
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9
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Frohlich JR, Alarcón CN, Toarmino CR, Sunseri AK, Hockman TM. Comparison of Serial Blood Collection by Facial Vein and Retrobulbar Methods in C57BL/6 Mice. JOURNAL OF THE AMERICAN ASSOCIATION FOR LABORATORY ANIMAL SCIENCE 2018; 57:382-391. [PMID: 29907166 DOI: 10.30802/aalas-jaalas-17-000134] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Many biomedical research protocols for mouse models involve serial blood collection and analysis. Two common techniques for serial blood collection in this species are the retrobulbar (RB, also called retroorbital) and facial vein (FV) methods. However, previous studies comparing these methods typically evaluated collection at a maximum of 2 time points. Here we compared hematologic values, adverse clinical effects, and histopathologic lesions in mice bled either once or serially (6 times) by using the FV or RB method. Mice (n = 48) were divided into 4 groups: single FV, single RB, serial FV and serial RB. Mice in the single-collection groups underwent a single blood collection by the indicated method, whereas those in the serial-collection groups were sampled once weekly for 6 consecutive weeks. All animals were euthanized and necropsied 2 wk after their last blood collection. Compared with all other groups, the serial FV group experienced more serious clinical adverse events, including 33% mortality, convulsions, head tilt, and hemorrhage from the ear canal and nares. In addition, mice in the FV groups had a significantly greater acute body weight loss compared with mice in the RB groups. Histologically, mice in both serial-collection groups had an increased incidence of tissue lesions compared with their respective single-collection groups. Importantly, only mice in the serial FV group had life-threatening histopathologic lesions, including cerebral hemorrhage or ischemia. Given these data, we conclude that serial blood collection in mice causes increased incidence of tissue damage compared with single sampling, and serial blood collection by the FV method causes substantial morbidity and mortality compared with the RB method.
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Affiliation(s)
- Jennifer R Frohlich
- Animal Care Program, University of California-San Diego, La Jolla, California, Office of Laboratory Animal Care, University of California Berkeley, Berkeley, California;,
| | - Christina N Alarcón
- Biomedical Sciences Program, University of California-San Diego, La Jolla, California
| | - Camille R Toarmino
- Department of Psychology, University of California-San Diego, La Jolla, California, BioTelemetry Research, Rochester, New York
| | - Anna K Sunseri
- Animal Care Program, University of California-San Diego, Department of Animal Resources, The Scripps Research Institute, La Jolla, California
| | - Tyler M Hockman
- Animal Care Program, University of California-San Diego, La Jolla, California, Division of Laboratory Animal Services, Augusta University, Augusta, Georgia
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10
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Stover KR, Lim S, Zhou TL, Stafford PM, Chow J, Li H, Sivanenthiran N, Mylvaganam S, Wu C, Weaver DF, Eubanks J, Zhang L. Susceptibility to hippocampal kindling seizures is increased in aging C57 black mice. IBRO Rep 2017; 3:33-44. [PMID: 30135940 PMCID: PMC6084868 DOI: 10.1016/j.ibror.2017.08.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 08/19/2017] [Accepted: 08/20/2017] [Indexed: 11/23/2022] Open
Abstract
The incidence of seizures increases with old age. Stroke, dementia and brain tumors are recognized risk factors for new-onset seizures in the aging populations and the incidence of these conditions also increased with age. Whether aging is associated with higher seizure susceptibility in the absence of the above pathologies remains unclear. We used classic kindling to explore this issue as the kindling model is highly reproducible and allows close monitoring of electrographic and motor seizure activities in individual animals. We kindled male young and aging mice (C57BL/6 strain, 2-3 and 18-22 months of age) via daily hippocampal CA3 stimulation and monitored seizure activity via video and electroencephalographic recordings. The aging mice needed fewer stimuli to evoke stage-5 motor seizures and exhibited longer hippocampal afterdischarges and more frequent hippocampal spikes relative to the young mice, but afterdischarge thresholds and cumulative afterdischarge durations to stage 5 motor seizures were not different between the two age groups. While hippocampal injury and structural alterations at cellular and micro-circuitry levels remain to be examined in the kindled mice, our present observations suggest that susceptibility to hippocampal CA3 kindling seizures is increased with aging in male C57 black mice.
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Affiliation(s)
- Kurt R. Stover
- Krembil Research Institute, University Health Network, Canada
| | - Stellar Lim
- Krembil Research Institute, University Health Network, Canada
| | - Terri-Lin Zhou
- Krembil Research Institute, University Health Network, Canada
| | | | - Jonathan Chow
- Krembil Research Institute, University Health Network, Canada
| | - Haoyuan Li
- Krembil Research Institute, University Health Network, Canada
| | | | | | - Chiping Wu
- Krembil Research Institute, University Health Network, Canada
| | - Donald F. Weaver
- Krembil Research Institute, University Health Network, Canada
- Departments of Chemistry, University of Toronto, Canada
- Departments of Medicine, University of Toronto, Canada
| | - James Eubanks
- Krembil Research Institute, University Health Network, Canada
- Departments of Surgery, University of Toronto, Canada
- University of Toronto Epilepsy Program, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health Network, Canada
- Departments of Medicine, University of Toronto, Canada
- University of Toronto Epilepsy Program, Canada
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11
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Bin NR, Song H, Wu C, Lau M, Sugita S, Eubanks JH, Zhang L. Continuous Monitoring via Tethered Electroencephalography of Spontaneous Recurrent Seizures in Mice. Front Behav Neurosci 2017; 11:172. [PMID: 28959196 PMCID: PMC5603658 DOI: 10.3389/fnbeh.2017.00172] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 08/31/2017] [Indexed: 12/16/2022] Open
Abstract
We describe here a simple, cost-effective apparatus for continuous tethered electroencephalographic (EEG) monitoring of spontaneous recurrent seizures in mice. We used a small, low torque slip ring as an EEG commutator, mounted the slip ring onto a standard mouse cage and connected rotary wires of the slip ring directly to animal's implanted headset. Modifications were made in the cage to allow for a convenient installation of the slip ring and accommodation of animal ambient activity. We tested the apparatus for hippocampal EEG recordings in adult C57 black mice. Spontaneous recurrent seizures were induced using extended hippocampal kindling (≥95 daily stimulation). Control animals underwent similar hippocampal electrode implantations but no stimulations were given. Combined EEG and webcam monitoring were performed for 24 h daily for 5–9 consecutive days. During the monitoring periods, the animals moved and accessed water and food freely and showed no apparent restriction in ambient cage activities. Ictal-like hippocampal EEG discharges and concurrent convulsive behaviors that are characteristics of spontaneous recurrent seizures were reliably recorded in a majority of the monitoring experiments in extendedly kindled but not in control animals. However, 1–2 rotary wires were disconnected from the implanted headset in some animals after continuous recordings for ≥5 days. The key features and main limitations of our recording apparatus are discussed.
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Affiliation(s)
- Na-Ryum Bin
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada
| | - Hongmei Song
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Neurosurgery, The First Hospital of Jilin UniversityJilin, China
| | - Chiping Wu
- Krembil Research Institute, University Health NetworkToronto, ON, Canada
| | - Marcus Lau
- Krembil Research Institute, University Health NetworkToronto, ON, Canada
| | - Shuzo Sugita
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada
| | - James H Eubanks
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,Department of Physiology, University of TorontoToronto, ON, Canada.,Division of Neurosurgery, Department of Surgery, University of TorontoToronto, ON, Canada.,The Epilepsy Research Program of Ontario Brain InstituteToronto, ON, Canada
| | - Liang Zhang
- Krembil Research Institute, University Health NetworkToronto, ON, Canada.,The Epilepsy Research Program of Ontario Brain InstituteToronto, ON, Canada.,Division of Neurology, Department of Medicine, University of TorontoToronto, ON, Canada
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12
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Alme KN, Engelsen BA, Naik M, Naess H. Identifying patients at risk of acute symptomatic seizure after ischemic stroke. Acta Neurol Scand 2017; 136:265-271. [PMID: 28025821 DOI: 10.1111/ane.12721] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/24/2016] [Indexed: 12/30/2022]
Abstract
BACKGROUND Contributors to post-stroke seizure research have advocated the need for prospective studies of acute symptomatic seizures after stroke. Identification of the patient at risk of seizure and the impact of the event on outcome is a prerequisite for this kind of research. The aim of this study was to identify risk factors, make an outline for a risk score, and look at consequences of seizure on short-time clinical outcomes. METHODS This registry-based study included patients with ischemic stroke admitted between 2007 and 2013. We identified variables associated with the presence of acute symptomatic seizures and made a risk score. Clinical outcome measures were modified Rankin scale, National Institute of Health Stroke Scale (NIHSS), and death at discharge or at day seven. RESULTS A total of 2598 ischemic stroke patients were included, 66 experiencing seizure within seven days of stroke. We found diabetes mellitus, NIHSS on admission, and cortical lesion to be associated with the risk of seizure. The risk score had a sensitivity of 58%, specificity of 85%, and a positive predictive value of 9% with a three-point cutoff. We found a negative effect of seizure on survival in mild-to-moderate strokes after adjusting for infections and stroke severity. CONCLUSIONS Because of low incidence and the lack of specific risk factors, acute symptomatic seizure after ischemic stroke is hard to predict. The negative effect of seizure on stroke outcome is uncertain, and more thorough studies are needed because of possible subtle or non-overt seizures.
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Affiliation(s)
- K. N. Alme
- Department for Geriatrics and Stroke; Medical Clinic; Haraldsplass Deaconess Hospital; Bergen Norway
| | - B. A. Engelsen
- Department of Neurology; Haukeland University Hospital; Norway Institute of clinical medicine; Bergen Norway
- University of Bergen; Bergen Norway
| | - M. Naik
- Department for Geriatrics and Stroke; Medical Clinic; Haraldsplass Deaconess Hospital; Bergen Norway
- University of Bergen; Bergen Norway
| | - H. Naess
- Department of Neurology; Haukeland University Hospital; Norway Institute of clinical medicine; Bergen Norway
- University of Bergen; Bergen Norway
- Centre for age-related medicine; Stavanger University Hospital; Stavanger Norway
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13
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Banoujaafar H, Monnier A, Pernet N, Quirié A, Garnier P, Prigent-Tessier A, Marie C. Brain BDNF levels are dependent on cerebrovascular endothelium-derived nitric oxide. Eur J Neurosci 2016; 44:2226-35. [PMID: 27306299 DOI: 10.1111/ejn.13301] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 06/07/2016] [Accepted: 06/09/2016] [Indexed: 11/29/2022]
Abstract
Scientific evidence continues to demonstrate a link between endothelial function and cognition. Besides, several studies have identified a complex interplay between nitric oxide (NO) and brain-derived neurotrophic factor (BDNF), a neurotrophin largely involved in cognition. Therefore, this study investigated the link between cerebral endothelium-derived NO and BDNF signaling. For this purpose, levels of BDNF and the phosphorylated form of endothelial NO synthase at serine 1177 (p-eNOS) were simultaneously measured in the cortex and hippocampus of rats subjected to either bilateral common carotid occlusion (n = 6), physical exercise (n = 6) or a combination of both (n = 6) as experimental approaches to modulate flow-induced NO production by the cerebrovasculature. Tropomyosin-related kinase type B (TrkB) receptors and its phosphorylated form at tyrosine 816 (p-TrkB) were also measured. Moreover, we investigated BDNF synthesis in brain slices exposed to the NO donor glyceryl trinitrate. Our results showed increased p-eNOS and BDNF levels after exercise and decreased levels after vascular occlusion as compared to corresponding controls, with a positive correlation between changes in p-eNOS and BDNF (r = 0.679). Exercise after vascular occlusion did not change levels of these proteins. Gyceryl trinitrate increased proBDNF and BDNF levels in brain slices, thus suggesting a possible causal relationship between NO and BDNF. Moreover, vascular occlusion, like exercise, resulted in increased TrkB and p-TrkB levels, whereas no change was observed with the combination of both. These results suggest that brain BDNF signaling may be dependent on cerebral endothelium-derived NO production.
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Affiliation(s)
- Hayat Banoujaafar
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France
| | - Alice Monnier
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France.,Department of Rehabilitation, University Hospital, Dijon, France
| | - Nicolas Pernet
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France
| | - Aurore Quirié
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France
| | - Philippe Garnier
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France.,IUT de Dijon, Département de Génie Biologique, Université de Bourgogne, Dijon, France
| | - Anne Prigent-Tessier
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France
| | - Christine Marie
- Unité INSERM U1093 Cognition, Action et Plasticité Sensorimotrice, University of Bourgogne Franche Comté, F-21000, Dijon, France
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14
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Xu T, Ou S, Liu X, Yu X, Yuan J, Huang H, Chen Y. Association between seizures after ischemic stroke and stroke outcome: A systematic review and meta-analysis. Medicine (Baltimore) 2016; 95:e4117. [PMID: 27399117 PMCID: PMC5058846 DOI: 10.1097/md.0000000000004117] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A systematic review and meta-analysis were performed to investigate a potential association between post-ischemic stroke seizures (PISS) and subsequent ischemic stroke (IS) outcome.A systematic search of two electronic databases (Medline and Embase) was conducted to identify studies that explored an association between PISS and IS outcome. The primary and secondary IS outcomes of interest were mortality and disability, respectively, with the latter defined as a score of 3 to 5 on the modified Rankin Scale.A total of 15 studies that were published between 1998 and 2015 with 926,492 participants were examined. The overall mortality rates for the patients with and without PISS were 34% (95% confidence interval [CI], 27-42%) and 18% (95% CI, 12-23%), respectively. The pooled relative ratio (RR) of mortality for the patients with PISS was 1.97 (95% CI, 1.48-2.61; I = 88.6%). The overall prevalence rates of disability in the patients with and without PISS were 60% (95% CI, 32-87%) and 41% (95% CI, 25-57%), respectively. Finally, the pooled RR of disability for the patients with PISS was 1.64 (95% CI, 1.32-2.02; I = 66.1%).PISS are significantly associated with higher risks of both mortality and disability. PISS indicate poorer prognoses in patients experiencing IS.
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Affiliation(s)
| | | | | | | | | | | | - Yangmei Chen
- Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, Chongqing, China
- Correspondence: Yangmei Chen, Department of Neurology, The Second Affiliated Hospital of Chongqing Medical University, 76 Linjiang Road, Yuzhong District, Chongqing, 400010, China (e-mail: )
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15
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Ye M, Bi YF, Ding L, Zhu WW, Gao W. Saikosaponin a functions as anti-epileptic effect in pentylenetetrazol induced rats through inhibiting mTOR signaling pathway. Biomed Pharmacother 2016; 81:281-287. [PMID: 27261605 DOI: 10.1016/j.biopha.2016.04.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Revised: 04/07/2016] [Accepted: 04/07/2016] [Indexed: 02/04/2023] Open
Abstract
OBJECTIVE Saikosaponin a (SSa), which is one major bioactive compound isolated from radix bupleuri, has been demonstrated to exhibit the properties of anticonvulsant and antiepileptic in few reports. This study aims to clarify the molecular mechanism by which SSa protects against pentylenetetrazol (PTZ) induced epileptic seizure. METHODS PTZ induced rat and hippocampal neuron were established. Treated rats or hippocampal neuron with SSa, and mTOR, P70S6K, IL-1β and TNF-α were then determined. RESULTS In PTZ induced rat, SSa significantly reduced seizure severity and duration while markedly elevated seizure latency, and it also down-regulated hippocampal p-mTOR, p-70S6K, L-1β and TNF-α expression. In hippocampal neurons exposed to PTZ, p-mTOR and p-70S6K expression levels were also decreased by SSa. Pre-incubated hippocampal neurons with leucine, an mTOR agonist, reversed the effects of SSa on decreasing cytokines expression and inhibiting cell apoptosis. The treatment of mTOR inhibitor rapamycin prevented against the increase of cytokines expression and hippocampal neuron apoptosis induced by PTZ. Leucine also canceled the alleviation of seizures and induction of hippocampal caspase-3 activity in PTZ induced rat with the treatment of SSa. CONCLUSION SSa protects against PTZ induced epileptic seizure and hippocampal neuron apoptosis through inhibiting mTOR signaling pathway.
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Affiliation(s)
- Ming Ye
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China
| | - Yong-Feng Bi
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China
| | - Li Ding
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China
| | - Wei-Wei Zhu
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China
| | - Wei Gao
- Department of Neurosurgery, The First Affiliated Hospital of Soochow University, Soochow 215006, China.
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16
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Wang J, Wu C, Peng J, Patel N, Huang Y, Gao X, Aljarallah S, Eubanks JH, McDonald R, Zhang L. Early-Onset Convulsive Seizures Induced by Brain Hypoxia-Ischemia in Aging Mice: Effects of Anticonvulsive Treatments. PLoS One 2015; 10:e0144113. [PMID: 26630670 PMCID: PMC4668036 DOI: 10.1371/journal.pone.0144113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 11/15/2015] [Indexed: 12/27/2022] Open
Abstract
Aging is associated with an increased risk of seizures/epilepsy. Stroke (ischemic or hemorrhagic) and cardiac arrest related brain injury are two major causative factors for seizure development in this patient population. With either etiology, seizures are a poor prognostic factor. In spite of this, the underlying pathophysiology of seizure development is not well understood. In addition, a standardized treatment regimen with anticonvulsants and outcome assessments following treatment has yet to be established for these post-ischemic seizures. Previous studies have modeled post-ischemic seizures in adult rodents, but similar studies in aging/aged animals, a group that mirrors a higher risk elderly population, remain sparse. Our study therefore aimed to investigate early-onset seizures in aging animals using a hypoxia-ischemia (HI) model. Male C57 black mice 18-20-month-old underwent a unilateral occlusion of the common carotid artery followed by a systemic hypoxic episode (8% O2 for 30 min). Early-onset seizures were detected using combined behavioral and electroencephalographic (EEG) monitoring. Brain injury was assessed histologically at different times post HI. Convulsive seizures were observed in 65% of aging mice post-HI but not in control aging mice following either sham surgery or hypoxia alone. These seizures typically occurred within hours of HI and behaviorally consisted of jumping, fast running, barrel-rolling, and/or falling (loss of the righting reflex) with limb spasms. No evident discharges during any convulsive seizures were seen on cortical-hippocampal EEG recordings. Seizure development was closely associated with acute mortality and severe brain injury on brain histological analysis. Intra-peritoneal injections of lorazepam and fosphenytoin suppressed seizures and improved survival but only when applied prior to seizure onset and not after. These findings together suggest that seizures are a major contributing factor to acute mortality in aging mice following severe brain ischemia and that early anticonvulsive treatment may prevent seizure genesis and improve overall outcomes.
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Affiliation(s)
- Justin Wang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Chiping Wu
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jessie Peng
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Nisarg Patel
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yayi Huang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxing Gao
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Salman Aljarallah
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Neurology Unit, Department of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James H. Eubanks
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario, Canada
| | - Robert McDonald
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Liang Zhang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Departments of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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17
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Wu C, Wang J, Peng J, Patel N, Huang Y, Gao X, Aljarallah S, Eubanks JH, McDonald R, Zhang L. Modeling early-onset post-ischemic seizures in aging mice. Exp Neurol 2015; 271:1-12. [PMID: 25943585 PMCID: PMC4758832 DOI: 10.1016/j.expneurol.2015.04.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2015] [Revised: 04/24/2015] [Accepted: 04/28/2015] [Indexed: 12/26/2022]
Abstract
Stroke is the leading cause of seizures and epilepsy in the aged population, with post-stroke seizures being a poor prognostic factor. The pathological processes underlying post-stroke seizures are not well understood and studies of these seizures in aging/aged animals remain scarce. Therefore, our primary objective was to model post-stroke seizures in aging mice (C57 black strain, 16-20 months-old), with a focus on early-onset, convulsive seizures that occur within 24-hours of brain ischemia. We utilized a middle cerebral artery occlusion model and examined seizure activity and brain injury using combined behavioral and electroencephalographic monitoring and histological assessments. Aging mice exhibited vigorous convulsive seizures within hours of the middle cerebral artery occlusion. These seizures manifested with jumping, rapid running, barrel-rolling and/or falling all in the absence of hippocampal-cortical electrographic discharges. Seizure development was closely associated with severe brain injury and acute mortality. Anticonvulsive treatments after seizure occurrence offered temporary seizure control but failed to improve animal survival. A separate cohort of adult mice (6-8 months-old) exhibited analogous early-onset convulsive seizures following the middle cerebral artery occlusion but had better survival outcomes following anticonvulsive treatment. Collectively, our data suggest that early-onset convulsive seizures are a result of severe brain ischemia in aging animals.
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Affiliation(s)
- Chiping Wu
- Toronto Western Research Institute, University Health Network, Canada
| | - Justin Wang
- Toronto Western Research Institute, University Health Network, Canada
| | - Jessie Peng
- Toronto Western Research Institute, University Health Network, Canada
| | - Nisarg Patel
- Toronto Western Research Institute, University Health Network, Canada
| | - Yayi Huang
- Toronto Western Research Institute, University Health Network, Canada
| | - Xiaoxing Gao
- Toronto Western Research Institute, University Health Network, Canada
| | - Salman Aljarallah
- Toronto Western Research Institute, University Health Network, Canada; Neurology Unit, Department of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James H Eubanks
- Toronto Western Research Institute, University Health Network, Canada; Department of Surgery (Neurosurgery), University of Toronto, Canada
| | - Robert McDonald
- Department of Neuroscience, University of Lethbridge, Canada
| | - Liang Zhang
- Toronto Western Research Institute, University Health Network, Canada; Department of Medicine (Neurology), University of Toronto, Canada.
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18
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Functional preservation of hippocampal CA1 by low-dose GYKI-52466 preconditioning in a rat model of hypoxic-ischemic brain injury. Brain Res 2015; 1613:100-9. [DOI: 10.1016/j.brainres.2015.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 04/02/2015] [Indexed: 11/19/2022]
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19
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Effects of neonatal hypoxic-ischemic episodes on late seizure outcomes in C57 black mice. Epilepsy Res 2015; 111:142-9. [PMID: 25769378 DOI: 10.1016/j.eplepsyres.2015.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/07/2015] [Accepted: 01/23/2015] [Indexed: 12/17/2022]
Abstract
We examined brain injury and seizures in adult C57 black mice (C57/BL6) that underwent neonatal hypoxic-ischemic (HI) episodes. Mouse pups of 7 days-old underwent a ligation of the right common carotid artery and a subsequent hypoxic challenge (8% O2 for 45min). Post-HI mice were implanted with intracranial electrodes at 2-3 months of age, subjected to behavioral/EEG recordings and hippocampal electrical stimulation in next several months and then euthanized for brain histological assessments at ages of 11-12 months. Histological assessment revealed ipsilateral brain infarctions in 9 post-HI animals. Evident motor seizures were found to occur in only 2 animals with histologically identified cystic infarctions but not in the 21 post-HI animals with or without infarctions. In response to the hippocampal stimulation, post-HI animals were less prone than sham controls to evoked motor seizures. We thus suggest that adult C57 black mice may have low propensity of developing epileptic seizures following the neonatal HI episode. Our present observations may be relevant to future investigation of post-HI epileptogenesis in mouse models.
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20
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Gooshe M, Abdolghaffari AH, Aleyasin AR, Chabouk L, Tofigh S, Hassanzadeh GR, Payandemehr B, Partoazar A, Azizi Y, Dehpour AR. Hypoxia/ischemia a key player in early post stroke seizures: modulation by opioidergic and nitrergic systems. Eur J Pharmacol 2014; 746:6-13. [PMID: 25449041 DOI: 10.1016/j.ejphar.2014.11.005] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2014] [Revised: 11/05/2014] [Accepted: 11/06/2014] [Indexed: 01/14/2023]
Abstract
Stroke is a leading cause of death, disability, and socioeconomic loss worldwide. All attempts at pharmacological reduction of the complications of stroke (e.g. post-stroke seizure, and brain׳s vulnerability to hypoxic/ischemic injury) have failed. Endogenous opioids and nitric oxide (NO) overproduction has been documented in brain hypoxia/ischemia (H/I), which can exert pro-convulsive effects. In this study, we aimed to examine the possible involvement of opioidergic and nitrergic pathways in the pathogenesis of post-stroke seizure. H/I was induced by right common carotid ligation and sham-operated mice served as controls. We demonstrated that right common carotid ligation decreases the threshold for clonic seizures induced by pentylenetetrazole (PTZ), a GABA antagonist. Furthermore, pro-convulsive effect of H/I following right common carotid ligation was blocked by naltrexone (NTX) (3mg/kg), NG-Nitro-l-arginine methyl ester (l-NAME) (10mg/kg), and aminoguanidine (AG) (100mg/kg) administration (P<0.001). Interestingly, co-administration of non-effective doses of NTX and l-NAME (1 and 0.5mg/kg, respectively) reverses epileptogenesis of H/I (P<0.001). In the same way, co-administration of non-effective doses of NTX and AG (1 and 5mg/kg, respectively), reverses epileptogenesis of H/I (P<0.001). Indeed, the histological studies performed on mice exposed to H/I confirmed our previous data. These findings suggest hyper-susceptibility to PTZ induced seizure following H/I is mediated by interaction of opioidergic, and iNOS/NO pathways. Therefore, our results identify new pharmacological targets and provide the rationale for a novel strategy to promote recovery after stroke and possibly other brain injuries.
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Affiliation(s)
- Maziar Gooshe
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Students׳ Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Amir Hossein Abdolghaffari
- Pharmacology and Applied Medicine, Department of Medicinal Plants Research Center, Institute of Medicinal Plants, ACECR, Karaj, Iran; International Campus, ICTUMS, Tehran University of Medical Sciences, Tehran, Iran
| | - Ali Reza Aleyasin
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Students׳ Scientific Research Center (SSRC), Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Leila Chabouk
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Sina Tofigh
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Gholam Reza Hassanzadeh
- Department of Anatomy, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Borna Payandemehr
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Alireza Partoazar
- Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Yaser Azizi
- Department of Physiology, School of Medicine, Tehran University of Medical Science, Tehran, Iran
| | - Ahmad Reza Dehpour
- Experimental Medicine Research Center, Tehran University of Medical Sciences, Tehran, Iran; Department of Pharmacology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
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21
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Jeffrey M, Lang M, Gane J, Chow E, Wu C, Zhang L. Novel anticonvulsive effects of progesterone in a mouse model of hippocampal electrical kindling. Neuroscience 2013; 257:65-75. [PMID: 24215976 DOI: 10.1016/j.neuroscience.2013.10.074] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2013] [Revised: 10/07/2013] [Accepted: 10/30/2013] [Indexed: 12/28/2022]
Abstract
Progesterone is a known anticonvulsant, with its inhibitory effects generally attributed to its secondary metabolite, 5α,3α-tetrahydroprogesterone (THP), and THP's enhancement of GABAA receptor activity. Accumulating evidence, however, suggests that progesterone may have non-genomic actions independent of the GABAA receptor. In this study, we explored THP/GABAA-independent anticonvulsive actions of progesterone in a mouse model of hippocampal kindling and in mouse entorhinal slices in vitro. Specifically, we examined the effects of progesterone in kindled mice with or without pretreatments with finasteride, a 5α-reductase inhibitor known to block the metabolism of progesterone to THP. In addition, we examined the effects of progesterone on entorhinal epileptiform potentials in the presence of a GABAA receptor antagonist picrotoxin and finasteride. Adult male mice were kindled via a daily stimulation protocol. Electroencephalographic (EEG) discharges were recorded from the hippocampus or cortex to assess "focal" or "generalized" seizure activity. Kindled mice were treated with intra-peritoneal injections of progesterone (10, 35, 100 and 160mg/kg) with or without finasteride pretreatment (50 or 100mg/kg), THP (1, 3.5, 10 and 30mg/kg), midazolam (2mg/kg) and carbamazepine (50mg/kg). Entorhinal cortical slices were prepared from naïve young mice, and repetitive epileptiform potentials were induced by 4-aminopyridine (100μM), picrotoxin (100μM) and finasteride (1μM). Pretreatment with finasteride did not abolish the anticonvulsant effects of progesterone. In finasteride-pretreated mice, progesterone at 100 and 160mg/kg decreased cortical but not hippocampal afterdischarges (ADs). Carbamazepine mimicked the effects of progesterone with finasteride pretreatments in decreasing cortical discharges and motor seizures, whereas midazolam produced effects similar to progesterone alone or THP in decreasing hippocampal ADs and motor seizures. In brain slices, progesterone at 1μM inhibited entorhinal epileptiform potentials in the presence of picrotoxin and finasteride. We suggest that progesterone may have THP/GABAA-dependent and independent anticonvulsive actions in the hippocampal-kindled mouse model.
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Affiliation(s)
- M Jeffrey
- Department of Pharmacology and Toxicology, University of Toronto, Canada; Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada; University of Toronto Epilepsy Research Program, Canada
| | - M Lang
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada
| | - J Gane
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada
| | - E Chow
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada
| | - C Wu
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada; University of Toronto Epilepsy Research Program, Canada
| | - L Zhang
- Department of Medicine (Neurology), University of Toronto, Canada; Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Canada; University of Toronto Epilepsy Research Program, Canada.
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Jeffrey M, Lang M, Gane J, Wu C, Burnham WM, Zhang L. A reliable method for intracranial electrode implantation and chronic electrical stimulation in the mouse brain. BMC Neurosci 2013; 14:82. [PMID: 23914984 PMCID: PMC3750568 DOI: 10.1186/1471-2202-14-82] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Accepted: 08/02/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Electrical stimulation of brain structures has been widely used in rodent models for kindling or modeling deep brain stimulation used clinically. This requires surgical implantation of intracranial electrodes and subsequent chronic stimulation in individual animals for several weeks. Anchoring screws and dental acrylic have long been used to secure implanted intracranial electrodes in rats. However, such an approach is limited when carried out in mouse models as the thin mouse skull may not be strong enough to accommodate the anchoring screws. We describe here a screw-free, glue-based method for implanting bipolar stimulating electrodes in the mouse brain and validate this method in a mouse model of hippocampal electrical kindling. METHODS Male C57 black mice (initial ages of 6-8 months) were used in the present experiments. Bipolar electrodes were implanted bilaterally in the hippocampal CA3 area for electrical stimulation and electroencephalographic recordings. The electrodes were secured onto the skull via glue and dental acrylic but without anchoring screws. A daily stimulation protocol was used to induce electrographic discharges and motor seizures. The locations of implanted electrodes were verified by hippocampal electrographic activities and later histological assessments. RESULTS Using the glue-based implantation method, we implanted bilateral bipolar electrodes in 25 mice. Electrographic discharges and motor seizures were successfully induced via hippocampal electrical kindling. Importantly, no animal encountered infection in the implanted area or a loss of implanted electrodes after 4-6 months of repetitive stimulation/recording. CONCLUSION We suggest that the glue-based, screw-free method is reliable for chronic brain stimulation and high-quality electroencephalographic recordings in mice. The technical aspects described this study may help future studies in mouse models.
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Affiliation(s)
- Melanie Jeffrey
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
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Colic S, Wither RG, Zhang L, Eubanks JH, Bardakjian BL. Characterization of seizure-like events recorded in vivo in a mouse model of Rett syndrome. Neural Netw 2013; 46:109-15. [PMID: 23727441 DOI: 10.1016/j.neunet.2013.05.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2013] [Revised: 05/01/2013] [Accepted: 05/05/2013] [Indexed: 10/26/2022]
Abstract
Rett syndrome is a neurodevelopmental disorder caused by mutations in the X-linked gene encoding methyl-CpG-binding protein 2 (MECP2). Spontaneous recurrent discharge episodes are displayed in Rett-related seizures as in other types of epilepsies. The aim of this paper is to investigate the seizure-like event (SLE) and inter-SLE states in a female MeCP2-deficient mouse model of Rett syndrome and compare them to those found in other spontaneous recurrent epilepsy models. The study was performed on a small population of female MeCP2-deficient mice using telemetric local field potential (LFP) recordings over a 24 h period. Durations of SLEs and inter-SLEs were extracted using a rule-based automated SLE detection system for both daytime and nighttime, as well as high and low power levels of the delta frequency range (0.5-4 Hz) of the recorded LFPs. The results suggest SLE occurrences are not influenced by circadian rhythms, but had a significantly greater association with delta power. Investigating inter-SLE and SLE states by fitting duration histograms to the gamma distribution showed that SLE initiation and termination were associated with random and deterministic mechanisms, respectively. These findings when compared to reported studies on epilepsy suggest that Rett-related seizures share many similarities with absence epilepsy.
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Affiliation(s)
- Sinisa Colic
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Canada.
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24
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Hippocampal excitability is increased in aged mice. Exp Neurol 2013; 247:710-9. [PMID: 23510762 DOI: 10.1016/j.expneurol.2013.03.012] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 03/05/2013] [Accepted: 03/08/2013] [Indexed: 12/22/2022]
Abstract
Aging is known to be associated with a high risk of developing seizure disorders. Currently, the mechanisms underlying this increased seizure susceptibility are not fully understood. Several previous studies have shown a loss of subgroups of GABAergic inhibitory interneurons in the hippocampus of aged rodents, yet the network excitability intrinsic to the aged hippocampus remains to be elucidated. The aim of this study is to examine age-dependent changes of hippocampal network activities in young adult (3-5 months), aging (16-18 months), and aged (24-28 months) mice. We conducted intracranial electroencephalographic (EEG) recordings in free-moving animals and extracellular recordings in hippocampal slices in vitro. EEG recordings revealed frequent spikes in aging and aged mice but only occasionally in young adults. These EEG spikes were suppressed following diazepam administration. Spontaneous field potentials with large amplitudes were frequently observed in hippocampal slices of aged mice but rarely in slices from young adults. These spontaneous field potentials originated from the CA3 area and their generation was dependent upon the excitatory glutamatergic activity. We therefore postulate that hippocampal network excitability is increased in aged mice and that such hyperactivity may be relevant to the increased seizure susceptibility observed in aged subjects.
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Wither RG, Lang M, Zhang L, Eubanks JH. Regional MeCP2 expression levels in the female MeCP2-deficient mouse brain correlate with specific behavioral impairments. Exp Neurol 2013; 239:49-59. [DOI: 10.1016/j.expneurol.2012.09.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Revised: 09/13/2012] [Accepted: 09/20/2012] [Indexed: 11/25/2022]
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Jung S, Schindler K, Findling O, Mono ML, Fischer U, Gralla J, El-Koussy M, Weck A, Galimanis A, Brekenfeld C, Schroth G, Mattle HP, Arnold M. Adverse effect of early epileptic seizures in patients receiving endovascular therapy for acute stroke. Stroke 2012; 43:1584-90. [PMID: 22535264 DOI: 10.1161/strokeaha.111.645358] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND AND PURPOSE The aim of this study was to analyze epileptic seizures and their impact on outcome in patients with stroke treated with endovascular therapy. METHODS From December 1992 to December 2010 we managed 805 patients with stroke with endovascular therapy. Epileptic seizures, bleeding complications, and 3-month outcomes were recorded prospectively. Outcomes of patients with early seizures (within 24 hours of stroke onset) and patients with late seizures (>24 hours after stroke) were compared with outcomes of seizure-free patients using uni- and multivariable statistics. RESULTS Forty-four of 805 patients (5.5%) had seizures between stroke onset and 3-month follow-up, 26 patients early and 18 late. Outcome of patients with late seizures and seizure-free patients was similar (P=0.144 and 0.807). Patients with early seizures had higher baseline National Institutes of Health Stroke Scale (P=0.023) and were younger (P=0.021) than seizure-free patients. Their mortality rate was 50% compared with 22.3% of the seizure free-patients (P=0.003), and less patients reached a favorable outcome (modified Rankin Scale 0-2): 15.4% and 46.8%, respectively (P=0.001). Early seizures independently predicted an unfavorable outcome (P=0.014; OR, 4.749; 95% CI, 0.376-3.914) and increased mortality (P=0.001; OR, 5.861; 95% CI, 0.770-2.947) in multiregression analysis. Patients with early seizures had a 1.6-fold higher risk for unfavorable outcome and a 2.2-fold higher risk for death compared with seizure-free patients. CONCLUSIONS Seizures within 24 hours of stroke onset were associated with worse outcome in patients with stroke undergoing endovascular therapy. Our findings confirm a need for trials for prophylactic anticonvulsive treatment in patients receiving endovascular therapy for acute stroke.
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Affiliation(s)
- Simon Jung
- Departments of Neurology, Inselspital, University Hospital Bern and University of Bern, Bern, Switzerland
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Wither RG, Colic S, Wu C, Bardakjian BL, Zhang L, Eubanks JH. Daily rhythmic behaviors and thermoregulatory patterns are disrupted in adult female MeCP2-deficient mice. PLoS One 2012; 7:e35396. [PMID: 22523589 PMCID: PMC3327685 DOI: 10.1371/journal.pone.0035396] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Accepted: 03/15/2012] [Indexed: 11/18/2022] Open
Abstract
Mutations in the X-linked gene encoding Methyl-CpG-binding protein 2 (MECP2) have been associated with neurodevelopmental and neuropsychiatric disorders including Rett Syndrome, X-linked mental retardation syndrome, severe neonatal encephalopathy, and Angelman syndrome. Although alterations in the performance of MeCP2-deficient mice in specific behavioral tasks have been documented, it remains unclear whether or not MeCP2 dysfunction affects patterns of periodic behavioral and electroencephalographic (EEG) activity. The aim of the current study was therefore to determine whether a deficiency in MeCP2 is sufficient to alter the normal daily rhythmic patterns of core body temperature, gross motor activity and cortical delta power. To address this, we monitored individual wild-type and MeCP2-deficient mice in their home cage environment via telemetric recording over 24 hour cycles. Our results show that the normal daily rhythmic behavioral patterning of cortical delta wave activity, core body temperature and mobility are disrupted in one-year old female MeCP2-deficient mice. Moreover, female MeCP2-deficient mice display diminished overall motor activity, lower average core body temperature, and significantly greater body temperature fluctuation than wild-type mice in their home-cage environment. Finally, we show that the epileptiform discharge activity in female MeCP2-deficient mice is more predominant during times of behavioral activity compared to inactivity. Collectively, these results indicate that MeCP2 deficiency is sufficient to disrupt the normal patterning of daily biological rhythmic activities.
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Affiliation(s)
- Robert G. Wither
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Sinisa Colic
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Chiping Wu
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario, Canada
| | - Berj L. Bardakjian
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario, Canada
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Liang Zhang
- Division of Fundamental Neurobiology, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
| | - James H. Eubanks
- Division of Genetics and Development, Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- University of Toronto Epilepsy Research Program, University of Toronto, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario, Canada
- * E-mail:
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El-Hayek YH, Wu C, Zhang L. Early suppression of intracranial EEG signals predicts ischemic outcome in adult mice following hypoxia-ischemia. Exp Neurol 2011; 231:295-303. [PMID: 21821027 DOI: 10.1016/j.expneurol.2011.07.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2011] [Revised: 07/03/2011] [Accepted: 07/17/2011] [Indexed: 11/18/2022]
Abstract
The objective of this study is to determine whether early alterations in intracranial EEG activity predict overall outcome in non-anesthetized adult mice following hypoxia-ischemia (HI). Adult C57BL/6 mice received surgical implantation of bilateral intracranial EEG electrodes in the hippocampus and cerebral cortex. Animals were subjected to a hypoxic-ischemic (HI) episode consisting of permanent occlusion of the right common carotid artery and subsequent systemic hypoxia (8% O(2) for 30 min). EEG activities were sorted based on the observance of motor seizures, poor physical outcome, brain injury, and mortality. EEG signals were quantified as amplitude, variance, and root mean square, and early alterations in these parameters were compared. Animals with poor-HI outcome exhibited longer and more profound suppression of EEG signals in the hippocampus ipsilateral to the carotid artery occlusion during HI. Of the parameters chosen to quantify EEG activity, root mean square demonstrated the greatest sensitivity in predicting subsequent outcome. Thus, ipsilateral hippocampal EEG signals are a reliable early marker for assessing HI outcome in adult mice, and further characterization of ischemic EEG signals may aid in the development of novel quantitative variables for use in animal models of experimental cerebral ischemia.
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