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Javadzadeh Y, Santos A, Aquilino MS, Mylvaganam S, Urban K, Carlen PL. Cannabidiol Exerts Anticonvulsant Effects Alone and in Combination with Δ 9-THC through the 5-HT1A Receptor in the Neocortex of Mice. Cells 2024; 13:466. [PMID: 38534310 DOI: 10.3390/cells13060466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 02/15/2024] [Accepted: 02/27/2024] [Indexed: 03/28/2024] Open
Abstract
Cannabinoids have shown potential in drug-resistant epilepsy treatment; however, we lack knowledge on which cannabinoid(s) to use, dosing, and their pharmacological targets. This study investigated (i) the anticonvulsant effect of Cannabidiol (CBD) alone and (ii) in combination with Delta-9 Tetrahydrocannabinol (Δ9-THC), as well as (iii) the serotonin (5-HT)1A receptor's role in CBD's mechanism of action. Seizure activity, induced by 4-aminopyridine, was measured by extracellular field recordings in cortex layer 2/3 of mouse brain slices. The anticonvulsant effect of 10, 30, and 100 µM CBD alone and combined with Δ9-THC was evaluated. To examine CBD's mechanism of action, slices were pre-treated with a 5-HT1A receptor antagonist before CBD's effect was evaluated. An amount of ≥30 µM CBD alone exerted significant anticonvulsant effects while 10 µM CBD did not. However, 10 µM CBD combined with low-dose Δ9-THC (20:3 ratio) displayed significantly greater anticonvulsant effects than either phytocannabinoid alone. Furthermore, blocking 5-HT1A receptors before CBD application significantly abolished CBD's effects. Thus, our results demonstrate the efficacy of low-dose CBD and Δ9-THC combined and that CBD exerts its effects, at least in part, through 5-HT1A receptors. These results could address drug-resistance while providing insight into CBD's mechanism of action, laying the groundwork for further testing of cannabinoids as anticonvulsants.
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Affiliation(s)
- Yasaman Javadzadeh
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Alexandra Santos
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada
| | - Mark S Aquilino
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Shanthini Mylvaganam
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada
| | | | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
- Department of Medicine (Neurology), University Health Network, Toronto, ON M5G 2C4, Canada
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2
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Wang XF, Vigouroux R, Syonov M, Baglaenko Y, Nikolakopoulou AM, Ringuette D, Rus H, DiStefano PV, Dufour S, Shabanzadeh AP, Lee S, Mueller BK, Charish J, Harada H, Fish JE, Wither J, Wälchli T, Cloutier JF, Zlokovic BV, Carlen PL, Monnier PP. The liver and muscle secreted HFE2-protein maintains central nervous system blood vessel integrity. Nat Commun 2024; 15:1037. [PMID: 38310100 PMCID: PMC10838306 DOI: 10.1038/s41467-024-45303-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Accepted: 01/19/2024] [Indexed: 02/05/2024] Open
Abstract
Liver failure causes breakdown of the Blood CNS Barrier (BCB) leading to damages of the Central-Nervous-System (CNS), however the mechanisms whereby the liver influences BCB-integrity remain elusive. One possibility is that the liver secretes an as-yet to be identified molecule(s) that circulate in the serum to directly promote BCB-integrity. To study BCB-integrity, we developed light-sheet imaging for three-dimensional analysis. We show that liver- or muscle-specific knockout of Hfe2/Rgmc induces BCB-breakdown, leading to accumulation of toxic-blood-derived fibrinogen in the brain, lower cortical neuron numbers, and behavioral deficits in mice. Soluble HFE2 competes with its homologue RGMa for binding to Neogenin, thereby blocking RGMa-induced downregulation of PDGF-B and Claudin-5 in endothelial cells, triggering BCB-disruption. HFE2 administration in female mice with experimental autoimmune encephalomyelitis, a model for multiple sclerosis, prevented paralysis and immune cell infiltration by inhibiting RGMa-mediated BCB alteration. This study has implications for the pathogenesis and potential treatment of diseases associated with BCB-dysfunction.
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Affiliation(s)
- Xue Fan Wang
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Institute of Biomedical and Biomaterial Engineering, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
| | - Robin Vigouroux
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
| | - Michal Syonov
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
| | - Yuriy Baglaenko
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
| | - Angeliki M Nikolakopoulou
- Department of Physiology and Neuroscience, The Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Dene Ringuette
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
| | - Horea Rus
- University of Maryland, School of Medicine, Department of Neurology, Baltimore, MD, 21201, USA
| | - Peter V DiStefano
- Toronto General Hospital Research Institute, University Health Network, 101 College St. Rm 3-308, Toronto, M5L 1L7, ON, Canada
| | - Suzie Dufour
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
| | - Alireza P Shabanzadeh
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
| | - Seunggi Lee
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
| | | | - Jason Charish
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
| | - Hidekiyo Harada
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
| | - Jason E Fish
- Toronto General Hospital Research Institute, University Health Network, 101 College St. Rm 3-308, Toronto, M5L 1L7, ON, Canada
| | - Joan Wither
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
| | - Thomas Wälchli
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Group of CNS Angiogenesis and Neurovascular Link, and Physician-Scientist Program, Institute for Regenerative Medicine, Neuroscience Center Zurich, and Division of Neurosurgery, University and University Hospital Zurich, Zurich, Switzerland
- Division of Neurosurgery, University Hospital Zurich, Zurich, Switzerland
- Division of Neurosurgery, Department of Surgery, Toronto Western Hospital, University Health Network, Toronto, Canada
| | - Jean-François Cloutier
- The Neuro - Montreal Neurological Institute and Hospital, 3801 Rue Université, Montréal, QC, H3A 2B4, Canada
| | - Berislav V Zlokovic
- Department of Physiology and Neuroscience, The Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada
- Institute of Biomedical and Biomaterial Engineering, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada
- Department of Physiology and Neuroscience, The Zilkha Neurogenetic Institute, Keck School of Medicine of the University of Southern California, Los Angeles, CA, USA
| | - Philippe P Monnier
- Krembil Research Institute, University Health Network, Krembil Discovery Tower, 60 Leonard St.,, Toronto, M5T 2O8, ON, Canada.
- Institute of Biomedical and Biomaterial Engineering, University of Toronto, 1 King's College circle,, Toronto, M5S 1A8, ON, Canada.
- Department of Ophthalmology and Vision Sciences, Faculty of Medicine, University of Toronto, 340 College St.,, ON, Toronto, M5T 3A9, Canada.
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3
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Ringuette D, EbrahimAmini A, Sangphosuk W, Aquilino MS, Carroll G, Ashley M, Bazzigaluppi P, Dufour S, Droguerre M, Stefanovic B, Levi O, Charveriat M, Monnier PP, Carlen PL. Spreading depolarization suppression from inter-astrocytic gap junction blockade assessed with multimodal imaging and a novel wavefront detection scheme. Neurotherapeutics 2024; 21:e00298. [PMID: 38241157 PMCID: PMC10903093 DOI: 10.1016/j.neurot.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 10/07/2023] [Indexed: 01/21/2024] Open
Abstract
Spreading depolarizations (SDs) are an enigmatic and ubiquitous co-morbidity of neural dysfunction. SDs are propagating waves of local field depolarization and increased extracellular potassium. They increase the metabolic demand on brain tissue, resulting in changes in tissue blood flow, and are associated with adverse neurological consequences including stroke, epilepsy, neurotrauma, and migraine. Their occurrence is associated with poor patient prognosis through mechanisms which are only partially understood. Here we show in vivo that two (structurally dissimilar) drugs, which suppress astroglial gap junctional communication, can acutely suppress SDs. We found that mefloquine hydrochloride (MQH), administered IP, slowed the propagation of the SD potassium waveform and intermittently led to its suppression. The hemodynamic response was similarly delayed and intermittently suppressed. Furthermore, in instances where SD led to transient tissue swelling, MQH reduced observable tissue displacement. Administration of meclofenamic acid (MFA) IP was found to reduce blood flow, both proximal and distal, to the site of SD induction, preceding a large reduction in the amplitude of the SD-associated potassium wave. We introduce a novel image processing scheme for SD wavefront localization under low-contrast imaging conditions permitting full-field wavefront velocity mapping and wavefront parametrization. We found that MQH administration delayed SD wavefront's optical correlates. These two clinically used drugs, both gap junctional blockers found to distinctly suppress SDs, may be of therapeutic benefit in the various brain disorders associated with recurrent SDs.
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Affiliation(s)
- Dene Ringuette
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Division of Genetics and Development, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada.
| | - Azin EbrahimAmini
- Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | - Weerawong Sangphosuk
- Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada
| | - Mark S Aquilino
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | - Gwennyth Carroll
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | - Max Ashley
- Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada
| | - Paolo Bazzigaluppi
- Sunnybrook Health Sciences Center, 2075 Bayview Ave., Toronto, Ontario M4N 3M5, Canada
| | - Suzie Dufour
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
| | | | - Bojana Stefanovic
- Department of Medical Biophysics, University of Toronto, 610 University Ave., Toronto, Ontario M5G 2M9, Canada; Sunnybrook Health Sciences Center, 2075 Bayview Ave., Toronto, Ontario M4N 3M5, Canada
| | - Ofer Levi
- The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada; The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Rd., Toronto, Ontario M5S 3G4, Canada
| | | | - Philippe P Monnier
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Division of Genetics and Development, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; Department of Ophthalmology & Vision Science, Faculty of Medicine, University of Toronto, 340 College St., Toronto, Ontario M5T 3A9, Canada
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Division of Genetics and Development, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; Krembil Neuroscience, Krembil Research Institute, 60 Leonard Ave., Toronto, Ontario M5T 2S8, Canada; The Institute Biomedical Engineering, University of Toronto, 164 College St., Toronto, Ontario M5S 3G9, Canada
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4
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Santos AC, Nader G, El Soufi El Sabbagh D, Urban K, Attisano L, Carlen PL. Treating Hyperexcitability in Human Cerebral Organoids Resulting from Oxygen-Glucose Deprivation. Cells 2023; 12:1949. [PMID: 37566028 PMCID: PMC10416870 DOI: 10.3390/cells12151949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/13/2023] [Accepted: 07/21/2023] [Indexed: 08/12/2023] Open
Abstract
Human cerebral organoids resemble the 3D complexity of the human brain and have the potential to augment current drug development pipelines for neurological disease. Epilepsy is a complex neurological condition characterized by recurrent seizures. A third of people with epilepsy do not respond to currently available pharmaceutical drugs, and there is not one drug that treats all subtypes; thus, better models of epilepsy are needed for drug development. Cerebral organoids may be used to address this unmet need. In the present work, human cerebral organoids are used along with electrophysiological methods to explore oxygen-glucose deprivation as a hyperexcitability agent. This activity is investigated in its response to current antiseizure drugs. Furthermore, the mechanism of action of the drug candidates is probed with qPCR and immunofluorescence. The findings demonstrate OGD-induced hyperexcitable changes in the cerebral organoid tissue, which is treated with cannabidiol and bumetanide. There is evidence for NKCC1 and KCC2 gene expression, as well as other genes and proteins involved in the complex development of GABAergic signaling. This study supports the use of organoids as a platform for modelling cerebral cortical hyperexcitability that could be extended to modelling epilepsy and used for drug discovery.
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Affiliation(s)
- Alexandra C. Santos
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - George Nader
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
| | - Dana El Soufi El Sabbagh
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A1, Canada
| | | | - Liliana Attisano
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A1, Canada
- Donnelly Centre, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Peter L. Carlen
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
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5
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Atiwiwat D, Aquilino M, Devinsky O, Bardakjian BL, Carlen PL. Interregional phase-amplitude coupling between theta rhythm in the nucleus tractus solitarius and high-frequency oscillations in the hippocampus during REM sleep in rats. Sleep 2023; 46:zsad027. [PMID: 36782374 PMCID: PMC10091087 DOI: 10.1093/sleep/zsad027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Revised: 11/30/2022] [Indexed: 02/15/2023] Open
Abstract
Cross-frequency coupling (CFC) between theta and high-frequency oscillations (HFOs) is predominant during active wakefulness, REM sleep and behavioral and learning tasks in rodent hippocampus. Evidence suggests that these state-dependent CFCs are linked to spatial navigation and memory consolidation processes. CFC studies currently include only the cortical and subcortical structures. To our knowledge, the study of nucleus tractus solitarius (NTS)-cortical structure CFC is still lacking. Here we investigate CFC in simultaneous local field potential recordings from hippocampal CA1 and the NTS during behavioral states in freely moving rats. We found a significant increase in theta (6-8 Hz)-HFO (120-160 Hz) coupling both within the hippocampus and between NTS theta and hippocampal HFOs during REM sleep. Also, the hippocampal HFOs were modulated by different but consistent phases of hippocampal and NTS theta oscillations. These findings support the idea that phase-amplitude coupling is both state- and frequency-specific and CFC analysis may serve as a tool to help understand the selective functions of neuronal network interactions in state-dependent information processing. Importantly, the increased NTS theta-hippocampal HFO coupling during REM sleep may represent the functional connectivity between these two structures which reflects the function of the hippocampus in visceral learning with the sensory information provided by the NTS. This gives a possible insight into an association between the sensory activity and REM-sleep dependent memory consolidation.
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Affiliation(s)
- Danita Atiwiwat
- Krembil Research Institute, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Biosignal Research Center for Health, Prince of Songkla University, Hat Yai, Songkhla, Thailand
- Division of Health and Applied Sciences, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Mark Aquilino
- Krembil Research Institute, University of Toronto, Toronto, ON, Canada
- Departments of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Orrin Devinsky
- New York University Langone Medical Center, Neurology, New York, NY, United States
| | - Berj L Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Peter L Carlen
- Krembil Research Institute, University of Toronto, Toronto, ON, Canada
- Department of Physiology, University of Toronto, Toronto, ON, Canada
- Departments of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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6
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Gravitis AC, Tufa U, Zukotynski K, Streiner DL, Friedman D, Laze J, Chinvarun Y, Devinsky O, Wennberg R, Carlen PL, Bardakjian BL. Ictal ECG-based assessment of sudden unexpected death in epilepsy. Front Neurol 2023; 14:1147576. [PMID: 36994379 PMCID: PMC10040863 DOI: 10.3389/fneur.2023.1147576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 02/21/2023] [Indexed: 03/16/2023] Open
Abstract
IntroductionPrevious case-control studies of sudden unexpected death in epilepsy (SUDEP) patients failed to identify ECG features (peri-ictal heart rate, heart rate variability, corrected QT interval, postictal heart rate recovery, and cardiac rhythm) predictive of SUDEP risk. This implied a need to derive novel metrics to assess SUDEP risk from ECG.MethodsWe applied Single Spectrum Analysis and Independent Component Analysis (SSA-ICA) to remove artifact from ECG recordings. Then cross-frequency phase-phase coupling (PPC) was applied to a 20-s mid-seizure window and a contour of −3 dB coupling strength was determined. The contour centroid polar coordinates, amplitude (alpha) and angle (theta), were calculated. Association of alpha and theta with SUDEP was assessed and a logistic classifier for alpha was constructed.ResultsAlpha was higher in SUDEP patients, compared to non-SUDEP patients (p < 0.001). Theta showed no significant difference between patient populations. The receiver operating characteristic (ROC) of a logistic classifier for alpha resulted in an area under the ROC curve (AUC) of 94% and correctly classified two test SUDEP patients.DiscussionThis study develops a novel metric alpha, which highlights non-linear interactions between two rhythms in the ECG, and is predictive of SUDEP risk.
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Affiliation(s)
- Adam C. Gravitis
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Uilki Tufa
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Katherine Zukotynski
- Department of Radiology, McMaster University, Hamilton, ON, Canada
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
| | - David L. Streiner
- Faculty of Health Sciences, McMaster University, Hamilton, ON, Canada
| | - Daniel Friedman
- Grossman School of Medicine, New York University, New York, NY, United States
| | - Juliana Laze
- Grossman School of Medicine, New York University, New York, NY, United States
| | - Yotin Chinvarun
- Department of Medicine, Phramongkutklao Royal Army Hospital, Bangkok, Thailand
| | - Orrin Devinsky
- Grossman School of Medicine, New York University, New York, NY, United States
| | - Richard Wennberg
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Peter L. Carlen
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Berj L. Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
- *Correspondence: Berj L. Bardakjian
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Saleem A, Santos AC, Aquilino MS, Sivitilli AA, Attisano L, Carlen PL. Modelling hyperexcitability in human cerebral cortical organoids: Oxygen/glucose deprivation most effective stimulant. Heliyon 2023; 9:e14999. [PMID: 37089352 PMCID: PMC10113787 DOI: 10.1016/j.heliyon.2023.e14999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 03/13/2023] [Accepted: 03/23/2023] [Indexed: 03/31/2023] Open
Abstract
Epilepsy is a common neurological disorder that affects 1% of the global population. The neonatal period constitutes the highest incidence of seizures. Despite the continual developments in seizure modelling and anti-epileptic drug development, the mechanisms involved in neonatal seizures remain poorly understood. This leaves infants with neonatal seizures at a high risk of death, poor prognosis of recovery and risk of developing neurological disorders later in life. Current in vitro platforms for modelling adult and neonatal epilepsies - namely acute cerebral brain slices or cell-derived cultures, both derived from animals-either lack a complex cytoarchitecture, high-throughput capabilities or physiological similarities to the neonatal human brain. Cerebral organoids, derived from human embryonic stem cells (hESCs), are an emerging technology that could better model neurodevelopmental disorders in the developing human brain. Herein, we study induced hyperexcitability in human cerebral cortical organoids - setting the groundwork for neonatal seizure modelling - using electrophysiological techniques and pharmacological manipulations. In neonatal seizures, energy failure - specifically due to deprivation of oxygen and glucose - is a consistent and reliable seizure induction method that has been used to study the underlying cellular and molecular mechanisms. Here, we applied oxygen-glucose deprivation (OGD) as well as common chemoconvulsants in 3-7-month-old cerebral organoids. Remarkably, OGD resulted in hyperexcitability, with increased power and spontaneous events compared to other common convulsants tested at the population level. These findings characterize OGD as the stimulus most capable of inducing hyperexcitable changes in cerebral organoid tissue, which could be extended to future modelling of neonatal epilepsies in cerebral organoids.
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Fasano A, Gorodetsy C, Paul D, Germann J, Loh A, Yan H, Carlen PL, Breitbart S, Lozano AM, Ibrahim GM, Kalia SK. Local Field Potential-Based DBS Programming: Proof-of-Concept in Pediatric Patient With Dystonia and Adult Patient With Seizures. Neuromodulation 2022. [DOI: 10.1016/j.neurom.2022.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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9
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EbrahimAmini A, Stefanovic B, Carlen PL. Effects of In Vivo Intracellular ATP Modulation on Neocortical Extracellular Potassium Concentration. Biomedicines 2022; 10:biomedicines10071568. [PMID: 35884873 PMCID: PMC9312484 DOI: 10.3390/biomedicines10071568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/28/2022] [Accepted: 06/28/2022] [Indexed: 11/23/2022] Open
Abstract
Neuronal and glial activity are dependent on the efflux of potassium ions into the extracellular space. Efflux of K is partly energy-dependent as the activity of pumps and channels which are involved in K transportation is ATP-dependent. In this study, we investigated the effect of decreased intracellular ATP concentration ([ATP]i) on the extracellular potassium ion concentration ([K]o). Using in vivo electrophysiological techniques, we measured neocortical [K]o and the local field potential (LFP) while [ATP]i was reduced through various pharmacological interventions. We observed that reducing [ATP]i led to raised [K]o and DC-shifts resembling spreading depolarization-like events. We proposed that most likely, the increased [K]o is mainly due to the impairment of the Na/K ATPase pump and the ATP-sensitive potassium channel in the absence of sufficient ATP, because Na/K ATPase inhibition led to increased [K]o and ATP-sensitive potassium channel impairment resulted in decreased [K]o. Therefore, an important consequence of decreased [ATP]i is an increased [K]o. The results of this study acknowledge one of the mechanisms involved in [K]o dynamics.
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Affiliation(s)
- Azin EbrahimAmini
- Krembil Research Institute, Toronto, ON M5T 0S8, Canada;
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Correspondence: ; Tel.: +647-648-6668
| | - Bojana Stefanovic
- Sunnybrook Health Sciences Center, Medical Biophysics, Toronto, ON M4N 3M5, Canada;
| | - Peter L. Carlen
- Krembil Research Institute, Toronto, ON M5T 0S8, Canada;
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
- Departments of Medicine and Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada
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10
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Whyte-Fagundes P, Taskina D, Safarian N, Zoidl C, Carlen PL, Donaldson LW, Zoidl GR. Panx1 channels promote both anti- and pro-seizure-like activities in the zebrafish via p2rx7 receptors and ATP signaling. Commun Biol 2022; 5:472. [PMID: 35585187 PMCID: PMC9117279 DOI: 10.1038/s42003-022-03356-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 04/12/2022] [Indexed: 11/08/2022] Open
Abstract
The molecular mechanisms of excitation/inhibition imbalances promoting seizure generation in epilepsy patients are not fully understood. Evidence suggests that Pannexin1 (Panx1), an ATP release channel, modulates the excitability of the brain. In this report, we performed electrophysiological, behavioral, and molecular phenotyping experiments on zebrafish larvae bearing genetic or pharmacological knockouts of Panx1a and Panx1b channels, each homologous to human PANX1. When Panx1a function is lost, or both channels are under pharmacological blockade, seizures with ictal-like events and seizure-like locomotion are reduced in the presence of pentylenetetrazol. Transcriptome profiling by RNA-seq demonstrates a spectrum of distinct metabolic and cell signaling states which correlate with the loss of Panx1a. Furthermore, the pro- and anticonvulsant activities of both Panx1 channels affect ATP release and involve the purinergic receptor P2rx7. Our findings suggest a subfunctionalization of Panx1 enabling dual roles in seizures, providing a unique and comprehensive perspective to understanding seizure mechanisms in the context of this channel.
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Affiliation(s)
- Paige Whyte-Fagundes
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada.
| | - Daria Taskina
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Nickie Safarian
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Christiane Zoidl
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada
- Department of Medicine, Physiology and BME, University of Toronto, 399 Bathurst St., 5w442, Toronto, ON, M5T 2S8, Canada
| | | | - Georg R Zoidl
- Department of Biology, York University, Toronto, ON, M3J1P3, Canada.
- Center of Vision Research (CVR), York University, Toronto, ON, M3J1P3, Canada.
- Krembil Research Institute, University Health Network, 60 Leonard Ave, Toronto, ON, M5T 1M8, Canada.
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11
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Moradi Chameh H, Rich S, Wang L, Chen FD, Zhang L, Carlen PL, Tripathy SJ, Valiante TA. Author Correction: Diversity amongst human cortical pyramidal neurons revealed via their sag currents and frequency preferences. Nat Commun 2022; 13:1689. [PMID: 35332144 PMCID: PMC8948281 DOI: 10.1038/s41467-022-29220-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Affiliation(s)
| | - Scott Rich
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Lihua Wang
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Fu-Der Chen
- Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada.,Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Liang Zhang
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada.,Departments of Medicine & Physiology, University of Toronto, Toronto, ON, Canada
| | - Peter L Carlen
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada.,Departments of Medicine & Physiology, University of Toronto, Toronto, ON, Canada.,Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Shreejoy J Tripathy
- Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON, Canada.,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.,Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Taufik A Valiante
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada. .,Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada. .,Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada. .,Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada. .,Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, Canada.
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12
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Tufa U, Gravitis A, Zukotynski K, Chinvarun Y, Devinsky O, Wennberg R, Carlen PL, Bardakjian BL. A Peri-Ictal EEG-Based Biomarker for Sudden Unexpected Death in Epilepsy (SUDEP) Derived From Brain Network Analysis. Front Netw Physiol 2022; 2:866540. [PMID: 36926093 PMCID: PMC10013055 DOI: 10.3389/fnetp.2022.866540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 03/14/2022] [Indexed: 11/13/2022]
Abstract
Sudden unexpected death in epilepsy (SUDEP) is the leading seizure-related cause of death in epilepsy patients. There are no validated biomarkers of SUDEP risk. Here, we explored peri-ictal differences in topological brain network properties from scalp EEG recordings of SUDEP victims. Functional connectivity networks were constructed and examined as directed graphs derived from undirected delta and high frequency oscillation (HFO) EEG coherence networks in eight SUDEP and 14 non-SUDEP epileptic patients. These networks were proxies for information flow at different spatiotemporal scales, where low frequency oscillations coordinate large-scale activity driving local HFOs. The clustering coefficient and global efficiency of the network were higher in the SUDEP group pre-ictally, ictally and post-ictally (p < 0.0001 to p < 0.001), with features characteristic of small-world networks. These results suggest that cross-frequency functional connectivity network topology may be a non-invasive biomarker of SUDEP risk.
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Affiliation(s)
- Uilki Tufa
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Adam Gravitis
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Katherine Zukotynski
- Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada.,Department of Radiology and Medicine, McMaster University, Hamilton, ON, Canada
| | - Yotin Chinvarun
- Comprehensive Epilepsy Program and Neurology Unit, Phramongkutklao Hospital, Bangkok, Thailand
| | - Orrin Devinsky
- Department of Neurology, New York University School of Medicine, New York, NY, United States
| | - Richard Wennberg
- Division of Neurology, Toronto Western Hospital, Toronto, ON, Canada
| | - Peter L Carlen
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Department of Neurology, New York University School of Medicine, New York, NY, United States.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Berj L Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON, Canada.,Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
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13
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Breton VL, Aquilino MS, Repudi S, Saleem A, Mylvaganam S, Abu-Swai S, Bardakjian BL, Aqeilan RI, Carlen PL. Altered neocortical oscillations and cellular excitability in an in vitro Wwox knockout mouse model of epileptic encephalopathy. Neurobiol Dis 2021; 160:105529. [PMID: 34634460 PMCID: PMC8609180 DOI: 10.1016/j.nbd.2021.105529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 09/24/2021] [Accepted: 10/07/2021] [Indexed: 12/02/2022] Open
Abstract
Loss of function mutations of the WW domain-containing oxidoreductase (WWOX) gene are associated with severe and fatal drug-resistant pediatric epileptic encephalopathy. Epileptic seizures are typically characterized by neuronal hyperexcitability; however, the specific contribution of WWOX to that hyperexcitability has yet to be investigated. Using a mouse model of neuronal Wwox-deletion that exhibit spontaneous seizures, in vitro whole-cell and field potential electrophysiological characterization identified spontaneous bursting activity in the neocortex, a marker of the underlying network hyperexcitability. Spectral analysis of the neocortical bursting events highlighted increased phase-amplitude coupling, and a propagation from layer II/III to layer V. These bursts were NMDAR and gap junction dependent. In layer II/III pyramidal neurons, Wwox knockout mice demonstrated elevated amplitude of excitatory post-synaptic currents, whereas the frequency and amplitude of inhibitory post-synaptic currents were reduced, as compared to heterozygote and wild-type littermate controls. Furthermore, these neurons were depolarized and demonstrated increased action potential frequency, sag current, and post-inhibitory rebound. These findings suggest WWOX plays an essential role in balancing neocortical excitability and provide insight towards developing therapeutics for those suffering from WWOX disorders.
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Affiliation(s)
- Vanessa L Breton
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada.
| | - Mark S Aquilino
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada.
| | - Srinivasarao Repudi
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Afifa Saleem
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada
| | - Shanthini Mylvaganam
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada
| | - Sara Abu-Swai
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Berj L Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Rami I Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
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14
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Fasano A, Gorodetsky C, Paul D, Germann J, Loh A, Yan H, Carlen PL, Breitbart S, Lozano AM, Ibrahim GM, Kalia SK. Local Field Potential-Based Programming: A Proof-of-Concept Pilot Study. Neuromodulation 2021; 25:271-275. [PMID: 34406680 DOI: 10.1111/ner.13520] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/29/2021] [Accepted: 07/19/2021] [Indexed: 01/28/2023]
Abstract
OBJECTIVES Programming deep brain stimulation (DBS) is still based on a trial-and-error approach, often becoming a time-consuming process for both treating physicians and patients. Several strategies have been proposed to streamline DBS programming, most of which are preliminary and mainly address Parkinson's disease, a condition readily responsive to DBS adjustments. In the present proof-of-principle pilot study, we successfully demonstrate that local field potentials (LFP)-based programming can be an effective approach when used for DBS indications that have a delayed temporal onset of benefit. MATERIALS AND METHODS A recently commercialized implantable pulse generator (IPG) with the capability to non-invasively and chronically stream live and/or record LFPs from DBS electrode after implantation was used to program one pediatric patient with generalized dystonia and an adult with seizures refractory to multiple medications and vagal nerve stimulation. RESULTS The IPG survey function detected a peak in the delta range (1.95 Hz) in the left globus pallidus of first patient. This LFP was detected when recording in the brain area adjacent to contacts 9 and 10 and absent when recording from other areas. The chronic recording of the 1.95 Hz LFP with two sets of stimulation showed a greater power increase with the settings associated with a worsening of dystonia. Broadband LFP home recording of "absence seizure" and "focal/partial seizure" was used in the second patient and reviewer with the IPG "timeline" and "event" functions. The chronic recording of the 2.93 Hz and 8.79 Hz (spit sensing) showed a reduced power with the stimulation setting associated with seizure control. CONCLUSIONS The approach presented in this pilot proof-of-concept study may inform and streamline the DBS programming for conditions requiring clinicians and patients to wait weeks before appreciating any clinical benefit. Prospective studies on larger samples of patients are warranted.
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Affiliation(s)
- Alfonso Fasano
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, ON, Canada.,Division of Neurology, University of Toronto, Toronto, ON, Canada.,Krembil Brain Institute, University Health Network, Toronto, ON, Canada.,Center for Advancing Neurotechnological Innovation to Application (CRANIA), Toronto, ON, Canada.,KITE, University Health Network, Toronto, ON, Canada
| | - Carolina Gorodetsky
- Edmond J. Safra Program in Parkinson's Disease, Morton and Gloria Shulman Movement Disorders Clinic, Toronto Western Hospital, UHN, Toronto, ON, Canada.,Division of Neurology, University of Toronto, Toronto, ON, Canada.,Division of Neurology, Hospital for Sick Children, Toronto, ON, Canada
| | - Darcia Paul
- Division of Neurosurgery, University of Toronto, Toronto, ON, Canada
| | - Jürgen Germann
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Aaron Loh
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada
| | - Han Yan
- Division of Neurosurgery, University of Toronto, Toronto, ON, Canada
| | - Peter L Carlen
- Division of Neurology, University of Toronto, Toronto, ON, Canada.,Krembil Brain Institute, University Health Network, Toronto, ON, Canada.,Epilepsy Program, Toronto Western Hospital, UHN, Toronto, ON, Canada
| | - Sara Breitbart
- Division of Neurosurgery, University of Toronto, Toronto, ON, Canada
| | - Andres M Lozano
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada.,Division of Neurosurgery, University of Toronto, Toronto, ON, Canada
| | - George M Ibrahim
- Division of Neurology, Hospital for Sick Children, Toronto, ON, Canada.,Division of Neurosurgery, University of Toronto, Toronto, ON, Canada
| | - Suneil K Kalia
- Krembil Brain Institute, University Health Network, Toronto, ON, Canada.,Center for Advancing Neurotechnological Innovation to Application (CRANIA), Toronto, ON, Canada.,KITE, University Health Network, Toronto, ON, Canada.,Division of Neurosurgery, University of Toronto, Toronto, ON, Canada
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15
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Steinberg DJ, Repudi S, Saleem A, Kustanovich I, Viukov S, Abudiab B, Banne E, Mahajnah M, Hanna JH, Stern S, Carlen PL, Aqeilan RI. Modeling genetic epileptic encephalopathies using brain organoids. EMBO Mol Med 2021; 13:e13610. [PMID: 34268881 PMCID: PMC8350905 DOI: 10.15252/emmm.202013610] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 06/03/2021] [Accepted: 06/04/2021] [Indexed: 11/09/2022] Open
Abstract
Developmental and epileptic encephalopathies (DEE) are a group of disorders associated with intractable seizures, brain development, and functional abnormalities, and in some cases, premature death. Pathogenic human germline biallelic mutations in tumor suppressor WW domain-containing oxidoreductase (WWOX) are associated with a relatively mild autosomal recessive spinocerebellar ataxia-12 (SCAR12) and a more severe early infantile WWOX-related epileptic encephalopathy (WOREE). In this study, we generated an in vitro model for DEEs, using the devastating WOREE syndrome as a prototype, by establishing brain organoids from CRISPR-engineered human ES cells and from patient-derived iPSCs. Using these models, we discovered dramatic cellular and molecular CNS abnormalities, including neural population changes, cortical differentiation malfunctions, and Wnt pathway and DNA damage response impairment. Furthermore, we provide a proof of concept that ectopic WWOX expression could potentially rescue these phenotypes. Our findings underscore the utility of modeling childhood epileptic encephalopathies using brain organoids and their use as a unique platform to test possible therapeutic intervention strategies.
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Affiliation(s)
- Daniel J Steinberg
- The Concern Foundation LaboratoriesDepartment of Immunology and Cancer Research‐IMRICThe Lautenberg Center for Immunology and Cancer ResearchHebrew University‐Hadassah Medical SchoolJerusalemIsrael
| | - Srinivasarao Repudi
- The Concern Foundation LaboratoriesDepartment of Immunology and Cancer Research‐IMRICThe Lautenberg Center for Immunology and Cancer ResearchHebrew University‐Hadassah Medical SchoolJerusalemIsrael
| | - Afifa Saleem
- Biomedical EngineeringUniversity of TorontoTorontoONCanada
- Krembil Research InstituteUniversity Health NetworkTorontoONCanada
| | | | - Sergey Viukov
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Baraa Abudiab
- The Concern Foundation LaboratoriesDepartment of Immunology and Cancer Research‐IMRICThe Lautenberg Center for Immunology and Cancer ResearchHebrew University‐Hadassah Medical SchoolJerusalemIsrael
| | - Ehud Banne
- Genetics InstituteKaplan Medical CenterHebrew University‐Hadassah Medical SchoolRehovotIsrael
- The Rina Mor Genetic InstituteWolfson Medical CenterHolonIsrael
| | - Muhammad Mahajnah
- Paediatric Neurology and Child Developmental CenterHillel Yaffe Medical CenterHaderaIsrael
- Rappaport Faculty of MedicineThe TechnionHaifaIsrael
| | - Jacob H Hanna
- Department of Molecular GeneticsWeizmann Institute of ScienceRehovotIsrael
| | - Shani Stern
- Sagol Department of NeurobiologyUniversity of HaifaHaifaIsrael
| | - Peter L Carlen
- Biomedical EngineeringUniversity of TorontoTorontoONCanada
- Krembil Research InstituteUniversity Health NetworkTorontoONCanada
- Departments of Medicine and PhysiologyUniversity of TorontoTorontoONCanada
| | - Rami I Aqeilan
- The Concern Foundation LaboratoriesDepartment of Immunology and Cancer Research‐IMRICThe Lautenberg Center for Immunology and Cancer ResearchHebrew University‐Hadassah Medical SchoolJerusalemIsrael
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16
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Moradi Chameh H, Rich S, Wang L, Chen FD, Zhang L, Carlen PL, Tripathy SJ, Valiante TA. Diversity amongst human cortical pyramidal neurons revealed via their sag currents and frequency preferences. Nat Commun 2021; 12:2497. [PMID: 33941783 PMCID: PMC8093195 DOI: 10.1038/s41467-021-22741-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2019] [Accepted: 03/24/2021] [Indexed: 02/03/2023] Open
Abstract
In the human neocortex coherent interlaminar theta oscillations are driven by deep cortical layers, suggesting neurons in these layers exhibit distinct electrophysiological properties. To characterize this potential distinctiveness, we use in vitro whole-cell recordings from cortical layers 2 and 3 (L2&3), layer 3c (L3c) and layer 5 (L5) of the human cortex. Across all layers we observe notable heterogeneity, indicating human cortical pyramidal neurons are an electrophysiologically diverse population. L5 pyramidal cells are the most excitable of these neurons and exhibit the most prominent sag current (abolished by blockade of the hyperpolarization activated cation current, Ih). While subthreshold resonance is more common in L3c and L5, we rarely observe this resonance at frequencies greater than 2 Hz. However, the frequency dependent gain of L5 neurons reveals they are most adept at tracking both delta and theta frequency inputs, a unique feature that may indirectly be important for the generation of cortical theta oscillations.
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Affiliation(s)
- Homeira Moradi Chameh
- grid.231844.80000 0004 0474 0428Krembil Brain Institute, University Health Network, Toronto, ON Canada
| | - Scott Rich
- grid.231844.80000 0004 0474 0428Krembil Brain Institute, University Health Network, Toronto, ON Canada
| | - Lihua Wang
- grid.231844.80000 0004 0474 0428Krembil Brain Institute, University Health Network, Toronto, ON Canada
| | - Fu-Der Chen
- grid.17063.330000 0001 2157 2938Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON Canada ,grid.450270.40000 0004 0491 5558Max Planck Institute of Microstructure Physics, Halle, Germany
| | - Liang Zhang
- grid.231844.80000 0004 0474 0428Krembil Brain Institute, University Health Network, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Departments of Medicine & Physiology, University of Toronto, Toronto, ON Canada
| | - Peter L. Carlen
- grid.231844.80000 0004 0474 0428Krembil Brain Institute, University Health Network, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Departments of Medicine & Physiology, University of Toronto, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Institute of Biomedical Engineering, University of Toronto, Toronto, ON Canada
| | - Shreejoy J. Tripathy
- grid.155956.b0000 0000 8793 5925Krembil Centre for Neuroinformatics, Centre for Addiction and Mental Health, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Institute of Medical Sciences, University of Toronto, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Department of Psychiatry, University of Toronto, Toronto, ON Canada
| | - Taufik A. Valiante
- grid.231844.80000 0004 0474 0428Krembil Brain Institute, University Health Network, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Institute of Biomedical Engineering, University of Toronto, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Institute of Medical Sciences, University of Toronto, Toronto, ON Canada ,grid.17063.330000 0001 2157 2938Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON Canada
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17
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Repudi S, Steinberg DJ, Elazar N, Breton VL, Aquilino MS, Saleem A, Abu-Swai S, Vainshtein A, Eshed-Eisenbach Y, Vijayaragavan B, Behar O, Hanna JJ, Peles E, Carlen PL, Aqeilan RI. Neuronal deletion of Wwox, associated with WOREE syndrome, causes epilepsy and myelin defects. Brain 2021; 144:3061-3077. [PMID: 33914858 DOI: 10.1093/brain/awab174] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2020] [Revised: 03/21/2021] [Accepted: 04/16/2021] [Indexed: 11/13/2022] Open
Abstract
WOREE syndrome caused by human germline biallelic mutations in WWOX is a neurodevelopmental disorder characterized by intractable epilepsy, severe developmental delay, ataxia and premature death at the age of 2-4 years. The underlying mechanisms of WWOX actions are poorly understood. In the current study, we show that specific neuronal deletion of murine Wwox produces phenotypes typical of the Wwox-null mutation leading to brain hyperexcitability, intractable epilepsy, ataxia and postnatal lethality. A significant decrease in transcript levels of genes involved in myelination was observed in mouse cortex and hippocampus. Wwox-mutant mice exhibited reduced maturation of oligodendrocytes, reduced myelinated axons and impaired axonal conductivity. Brain hyperexcitability and hypomyelination were also revealed in human brain organoids with a WWOX deletion. These findings provide cellular and molecular evidence for myelination defects and hyperexcitability in the WOREE syndrome linked to neuronal function of WWOX.
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Affiliation(s)
- Srinivasarao Repudi
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Daniel J Steinberg
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Nimrod Elazar
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Vanessa L Breton
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Mark S Aquilino
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Afifa Saleem
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Sara Abu-Swai
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Anna Vainshtein
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Yael Eshed-Eisenbach
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Bharath Vijayaragavan
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Oded Behar
- Department of Developmental Biology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
| | - Jacob J Hanna
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Elior Peles
- Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, Canada
| | - Rami I Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem, Israel
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18
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Banne E, Abudiab B, Abu-Swai S, Repudi SR, Steinberg DJ, Shatleh D, Alshammery S, Lisowski L, Gold W, Carlen PL, Aqeilan RI. Neurological Disorders Associated with WWOX Germline Mutations-A Comprehensive Overview. Cells 2021; 10:824. [PMID: 33916893 PMCID: PMC8067556 DOI: 10.3390/cells10040824] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 12/13/2022] Open
Abstract
The transcriptional regulator WW domain-containing oxidoreductase (WWOX) is a key player in a number of cellular and biological processes including tumor suppression. Recent evidence has emerged associating WWOX with non-cancer disorders. Patients harboring pathogenic germline bi-allelic WWOX variants have been described with the rare devastating neurological syndromes autosomal recessive spinocerebellar ataxia 12 (SCAR12) (6 patients) and WWOX-related epileptic encephalopathy (DEE28 or WOREE syndrome) (56 patients). Individuals with these syndromes present with a highly heterogenous clinical spectrum, the most common clinical symptoms being severe epileptic encephalopathy and profound global developmental delay. Knowledge of the underlying pathophysiology of these syndromes, the range of variants of the WWOX gene and its genotype-phenotype correlations is limited, hampering therapeutic efforts. Therefore, there is a critical need to identify and consolidate all the reported variants in WWOX to distinguish between disease-causing alleles and their associated severity, and benign variants, with the aim of improving diagnosis and increasing therapeutic efforts. Here, we provide a comprehensive review of the literature on WWOX, and analyze the pathogenic variants from published and unpublished reports by collecting entries from the ClinVar, DECIPHER, VarSome, and PubMed databases to generate the largest dataset of WWOX pathogenic variants. We estimate the correlation between variant type and patient phenotype, and delineate the impact of each variant, and used GnomAD to cross reference these variants found in the general population. From these searches, we generated the largest published cohort of WWOX individuals. We conclude with a discussion on potential personalized medicine approaches to tackle the devastating disorders associated with WWOX mutations.
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Affiliation(s)
- Ehud Banne
- The Genetic Institute, Kaplan Medical Center, Hebrew University-Hadassah Medical School, Rehovot 76100, Israel;
- The Rina Mor Genetic Institute, Wolfson Medical Center, Holon 58100, Israel
| | - Baraa Abudiab
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; (B.A.); (S.A.-S.); (D.J.S.); (S.R.R.); (D.S.)
| | - Sara Abu-Swai
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; (B.A.); (S.A.-S.); (D.J.S.); (S.R.R.); (D.S.)
| | - Srinivasa Rao Repudi
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; (B.A.); (S.A.-S.); (D.J.S.); (S.R.R.); (D.S.)
| | - Daniel J. Steinberg
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; (B.A.); (S.A.-S.); (D.J.S.); (S.R.R.); (D.S.)
| | - Diala Shatleh
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; (B.A.); (S.A.-S.); (D.J.S.); (S.R.R.); (D.S.)
| | - Sarah Alshammery
- Faculty of Medicine and Health, School of Medical Sciences and Discipline of Child and Adolescent Health, The University of Sydney, Westmead 2145, NSW, Australia; (S.A.); (W.G.)
| | - Leszek Lisowski
- Translational Vectorology Research Unit, Children’s Medical Research Institute, The University of Sydney, Westmead 2145, NSW, Australia;
- Laboratory of Molecular Oncology and Innovative Therapies, Military Institute of Medicine, 04-141 Warsaw, Poland
| | - Wendy Gold
- Faculty of Medicine and Health, School of Medical Sciences and Discipline of Child and Adolescent Health, The University of Sydney, Westmead 2145, NSW, Australia; (S.A.); (W.G.)
- Molecular Neurobiology Research Laboratory, Kids Research, Children’s Hospital at Westmead and The Children’s Medical Research Institute, Westmead 2145, NSW, Australia
- Kids Neuroscience Centre, Kids Research, Children’s Hospital at Westmead, Westmead 2145, NSW, Australia
| | - Peter L. Carlen
- Krembil Research Institute, University Health Network and Department of Medicine, Physiology and BME, University of Toronto, Toronto, ON M5T 1M8, Canada;
| | - Rami I. Aqeilan
- The Concern Foundation Laboratories, The Lautenberg Center for Immunology and Cancer Research, Department of Immunology and Cancer Research-IMRIC, Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel; (B.A.); (S.A.-S.); (D.J.S.); (S.R.R.); (D.S.)
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19
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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: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [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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20
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Liu H, Carlen PL, Zhang L. Examinations of Bilateral Epileptiform Activities in Hippocampal Slices Obtained From Young Mice. Front Cell Neurosci 2021; 14:593840. [PMID: 33551747 PMCID: PMC7854570 DOI: 10.3389/fncel.2020.593840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 12/21/2020] [Indexed: 12/02/2022] Open
Abstract
Bilateral interconnections through the hippocampal commissure play important roles in synchronizing or spreading hippocampal seizure activities. Intact hippocampi or bilateral hippocampal slices have been isolated from neonatal or immature rats (6–7 or 12–21 days old, respectively) and the mechanisms underlying the bilateral synchrony of hippocampal epileptiform activities have been investigated. However, the feasibility of examining bilateral epileptiform activities of more developed hippocampal circuitry in vitro remains to be explored. For this, we prepared bilateral hippocampal slices from C57 black mice, a strain commonly used in neuroscience and for genetic/molecular modifications. Young mice (21–24-day-old) were used in most experiments. A 600-μm-thick slice was obtained from each mouse by horizontal vibratome sectioning. Bilateral dorsal hippocampal and connecting dorsal hippocampal commissure (DHC) tissues were preserved in the slice and extrahippocampal tissues were removed. Slices were recorded in a submerged chamber mainly at a room temperature (21–22°C). Bilateral CA3 areas were monitored by extracellular recordings, and unilateral electrical stimulation was used to elicit CA3 synaptic field potentials. The unilateral stimulation could elicit population spikes in the contralateral CA3 area. These contralateral spikes were attenuated by inhibiting synaptic transmission with cobalt-containing medium and were abolished when a cut was made at the DHC. Self-sustained and bilaterally correlated epileptiform potentials were observed following application of 4-aminopyradine and became independent after the DHC cut. Bilateral hippocampal activities were detectable in some slices of adult mice and/or at 35–36°C, but with smaller amplitudes and variable waveforms compared to those observed from slices of young mice and at the room temperature. Together, these observations suggested that examining bilateral epileptiform activities in hippocampal slices of young mice is feasible. The weaknesses and limitations of this preparation and our experimentation are discussed.
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Affiliation(s)
- Haiyu Liu
- Department of Neurosurgery, The First Hospital of Jilin University, Changchun, China.,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
| | - 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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21
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Grigorovsky V, Jacobs D, Breton VL, Tufa U, Lucasius C, Del Campo JM, Chinvarun Y, Carlen PL, Wennberg R, Bardakjian BL. Delta-gamma phase-amplitude coupling as a biomarker of postictal generalized EEG suppression. Brain Commun 2020; 2:fcaa182. [PMID: 33376988 PMCID: PMC7750942 DOI: 10.1093/braincomms/fcaa182] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 09/22/2020] [Accepted: 09/24/2020] [Indexed: 12/15/2022] Open
Abstract
Postictal generalized EEG suppression is the state of suppression of electrical activity at the end of a seizure. Prolongation of this state has been associated with increased risk of sudden unexpected death in epilepsy, making characterization of underlying electrical rhythmic activity during postictal suppression an important step in improving epilepsy treatment. Phase-amplitude coupling in EEG reflects cognitive coding within brain networks and some of those codes highlight epileptic activity; therefore, we hypothesized that there are distinct phase-amplitude coupling features in the postictal suppression state that can provide an improved estimate of this state in the context of patient risk for sudden unexpected death in epilepsy. We used both intracranial and scalp EEG data from eleven patients (six male, five female; age range 21–41 years) containing 25 seizures, to identify frequency dynamics, both in the ictal and postictal EEG suppression states. Cross-frequency coupling analysis identified that during seizures there was a gradual decrease of phase frequency in the coupling between delta (0.5–4 Hz) and gamma (30+ Hz), which was followed by an increased coupling between the phase of 0.5–1.5 Hz signal and amplitude of 30–50 Hz signal in the postictal state as compared to the pre-seizure baseline. This marker was consistent across patients. Then, using these postictal-specific features, an unsupervised state classifier—a hidden Markov model—was able to reliably classify four distinct states of seizure episodes, including a postictal suppression state. Furthermore, a connectome analysis of the postictal suppression states showed increased information flow within the network during postictal suppression states as compared to the pre-seizure baseline, suggesting enhanced network communication. When the same tools were applied to the EEG of an epilepsy patient who died unexpectedly, ictal coupling dynamics disappeared and postictal phase-amplitude coupling remained constant throughout. Overall, our findings suggest that there are active postictal networks, as defined through coupling dynamics that can be used to objectively classify the postictal suppression state; furthermore, in a case study of sudden unexpected death in epilepsy, the network does not show ictal-like phase-amplitude coupling features despite the presence of convulsive seizures, and instead demonstrates activity similar to postictal. The postictal suppression state is a period of elevated network activity as compared to the baseline activity which can provide key insights into the epileptic pathology.
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Affiliation(s)
| | - Daniel Jacobs
- Institute of Biomedical Engineering, University of Toronto, Canada
| | | | - Uilki Tufa
- Institute of Biomedical Engineering, University of Toronto, Canada
| | - Christopher Lucasius
- Edward S. Rogers Sr. Department of Electrical & Computer Engineering, University of Toronto, Canada
| | | | - Yotin Chinvarun
- Comprehensive Epilepsy Program and Neurology Unit, Phramongkutklao Hospital, Thailand
| | - Peter L Carlen
- Institute of Biomedical Engineering, University of Toronto, Canada.,Department of Physiology, University of Toronto, Canada.,Division of Neurology, Toronto Western Hospital, Canada
| | | | - Berj L Bardakjian
- Institute of Biomedical Engineering, University of Toronto, Canada.,Edward S. Rogers Sr. Department of Electrical & Computer Engineering, University of Toronto, Canada
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22
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Aquilino MS, Whyte-Fagundes P, Lukewich MK, Zhang L, Bardakjian BL, Zoidl GR, Carlen PL. Pannexin-1 Deficiency Decreases Epileptic Activity in Mice. Int J Mol Sci 2020; 21:ijms21207510. [PMID: 33053775 PMCID: PMC7589538 DOI: 10.3390/ijms21207510] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 10/02/2020] [Accepted: 10/03/2020] [Indexed: 02/07/2023] Open
Abstract
Objective: Pannexin-1 (Panx1) is suspected of having a critical role in modulating neuronal excitability and acute neurological insults. Herein, we assess the changes in behavioral and electrophysiological markers of excitability associated with Panx1 via three distinct models of epilepsy. Methods Control and Panx1 knockout C57Bl/6 mice of both sexes were monitored for their behavioral and electrographic responses to seizure-generating stimuli in three epilepsy models—(1) systemic injection of pentylenetetrazol, (2) acute electrical kindling of the hippocampus and (3) neocortical slice exposure to 4-aminopyridine. Phase-amplitude cross-frequency coupling was used to assess changes in an epileptogenic state resulting from Panx1 deletion. Results: Seizure activity was suppressed in Panx1 knockouts and by application of Panx1 channel blockers, Brilliant Blue-FCF and probenecid, across all epilepsy models. In response to pentylenetetrazol, WT mice spent a greater proportion of time experiencing severe (stage 6) seizures as compared to Panx1-deficient mice. Following electrical stimulation of the hippocampal CA3 region, Panx1 knockouts had significantly shorter evoked afterdischarges and were resistant to kindling. In response to 4-aminopyridine, neocortical field recordings in slices of Panx1 knockout mice showed reduced instances of electrographic seizure-like events. Cross-frequency coupling analysis of these field potentials highlighted a reduced coupling of excitatory delta–gamma and delta-HF rhythms in the Panx1 knockout. Significance: These results suggest that Panx1 plays a pivotal role in maintaining neuronal hyperexcitability in epilepsy models and that genetic or pharmacological targeting of Panx1 has anti-convulsant effects.
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Affiliation(s)
- Mark S. Aquilino
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
- Correspondence:
| | - Paige Whyte-Fagundes
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M5S 3G9, Canada; (P.W.-F.); (G.R.Z.)
| | - Mark K. Lukewich
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
| | - Liang Zhang
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
| | - Berj L. Bardakjian
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
| | - Georg R. Zoidl
- Department of Biology, York University, 4700 Keele Street, Toronto, ON M5S 3G9, Canada; (P.W.-F.); (G.R.Z.)
| | - Peter L. Carlen
- IBME, University of Toronto, 164 College Street, Rosebrugh Building, Room 407, Toronto, ON M5S 3G9, Canada; (B.L.B.); (P.L.C.)
- Krembil Research Institute, University Health Network, 135 Nassau Street, Toronto, ON M5T 1M8, Canada; (M.K.L.); (L.Z.)
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23
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Breton VL, Dufour S, Chinvarun Y, Del Campo JM, Bardakjian BL, Carlen PL. Transitions between neocortical seizure and non-seizure-like states and their association with presynaptic glutamate release. Neurobiol Dis 2020; 146:105124. [PMID: 33010482 DOI: 10.1016/j.nbd.2020.105124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/16/2020] [Accepted: 09/28/2020] [Indexed: 11/28/2022] Open
Abstract
The transition between seizure and non-seizure states in neocortical epileptic networks is governed by distinct underlying dynamical processes. Based on the gamma distribution of seizure and inter-seizure durations, over time, seizures are highly likely to self-terminate; whereas, inter-seizure durations have a low chance of transitioning back into a seizure state. Yet, the chance of a state transition could be formed by multiple overlapping, unknown synaptic mechanisms. To identify the relationship between the underlying synaptic mechanisms and the chance of seizure-state transitions, we analyzed the skewed histograms of seizure durations in human intracranial EEG and seizure-like events (SLEs) in local field potential activity from mouse neocortical slices, using an objective method for seizure state classification. While seizures and SLE durations were demonstrated to have a unimodal distribution (gamma distribution shape parameter >1), suggesting a high likelihood of terminating, inter-SLE intervals were shown to have an asymptotic exponential distribution (gamma distribution shape parameter <1), suggesting lower probability of cessation. Then, to test cellular mechanisms for these distributions, we studied the modulation of synaptic neurotransmission during, and between, the in vitro SLEs. Using simultaneous local field potential and whole-cell voltage clamp recordings, we found a suppression of presynaptic glutamate release at SLE termination, as demonstrated by electrically- and optogenetically-evoked excitatory postsynaptic currents (EPSCs), and focal hypertonic sucrose application. Adenosine A1 receptor blockade interfered with the suppression of this release, changing the inter-SLE shape parameter from asymptotic exponential to unimodal, altering the chance of state transition occurrence with time. These findings reveal a critical role for presynaptic glutamate release in determining the chance of neocortical seizure state transitions.
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Affiliation(s)
- Vanessa L Breton
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada.
| | - Suzie Dufour
- Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; National Optics Institute, Biophotonics, Quebec, Canada G1P 4S4
| | - Yotin Chinvarun
- Comprehensive Epilepsy Program and Neurology Unit, Phramongkutklao Hospital, Bangkok, Thailand
| | - Jose Martin Del Campo
- Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
| | - Berj L Bardakjian
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario M5S 3G4, Canada
| | - Peter L Carlen
- Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Ontario M5S 1A8, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario M5S 3G9, Canada; Krembil Research Institute, Division of Fundamental Neurobiology, Toronto Western Hospital, Toronto, Ontario M5T 0S8, Canada; Department of Medicine (Neurology), University Health Network, Toronto, Ontario M5G 2C4, Canada
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24
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Rafiee M, Patel K, Groppe DM, Andrade DM, Bercovici E, Bui E, Carlen PL, Reid A, Tai P, Weaver D, Wennberg R, Valiante TA. Daily listening to Mozart reduces seizures in individuals with epilepsy: A randomized control study. Epilepsia Open 2020; 5:285-294. [PMID: 32524054 PMCID: PMC7278546 DOI: 10.1002/epi4.12400] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 05/02/2020] [Accepted: 05/03/2020] [Indexed: 11/06/2022] Open
Abstract
Objective Epilepsy is one of the most common neurological disorders . Many individuals continue to have seizures despite medical and surgical treatments, suggesting adjunctive management strategies are required. Promising effects of daily listening to Mozart on reducing seizure frequency in individuals with epilepsy have been demonstrated over the last 20 years, but not in a rigorously controlled manner. In this study, we compared the effect on seizure frequency of daily listening to either Mozart K.448 or a spectrally similar, yet non‐rhythmic control piece. We hypothesized that there would be no difference in seizure counts when participants listened to Mozart K.448 vs when they listened to the control piece. Methods We employed a randomized crossover design, in which each participant was exposed to both three months of daily listening to the first six minutes of Sonata for two pianos in D major by Mozart (Mozart K.448; treatment period) and three months of daily listening to phase‐scrambled version (control period). There was a three‐month baseline and a three‐month follow‐up period before and after the six‐month listening period, respectively. Change in seizure counts obtained from the seizure diaries was considered as the main study outcome. Results Using three methodologies to investigate the existence of the treatment effect (paired t test, estimation statistics and plots, and Cohen's d), our results revealed a reduction in seizure counts during the treatment period, which was not observed for the control period (P‐value < .001). Significance Using a spectrally similar control piece, our study advances previous reports that were limited by a “no music” control condition. Daily listening to Mozart K.448 was associated with reducing seizure frequency in adult individuals with epilepsy. These results suggest that daily Mozart listening may be considered as an adjunctive therapeutic option to reduce seizure burden in individuals with epilepsy.
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Affiliation(s)
| | - Kramay Patel
- Krembil Brain Institute Toronto ON Canada.,Institute of Biomaterials and Biomedical Engineering, and Electrical and Computer Engineering University of Toronto Toronto ON Canada
| | | | - Danielle M Andrade
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada
| | - Eduard Bercovici
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada
| | - Esther Bui
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada
| | - Peter L Carlen
- Krembil Brain Institute Toronto ON Canada.,Institute of Biomaterials and Biomedical Engineering, and Electrical and Computer Engineering University of Toronto Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada.,Department of Physiology University of Toronto Toronto ON Canada.,Division of Neurosurgery Department of Surgery University of Toronto Toronto ON Canada
| | - Aylin Reid
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada
| | - Peter Tai
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada
| | - Donald Weaver
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada.,Department of Chemistry University of Toronto Toronto ON Canada
| | - Richard Wennberg
- Krembil Brain Institute Toronto ON Canada.,Division of Neurology Department of Medicine University of Toronto Toronto ON Canada
| | - Taufik A Valiante
- Krembil Brain Institute Toronto ON Canada.,Institute of Biomaterials and Biomedical Engineering, and Electrical and Computer Engineering University of Toronto Toronto ON Canada.,Division of Neurosurgery Department of Surgery University of Toronto Toronto ON Canada.,Institute of Medical Science Faculty of Medicine University of Toronto Toronto ON Canada
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25
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Lertwittayanon W, Devinsky O, Carlen PL. Cardiorespiratory depression from brainstem seizure activity in freely moving rats. Neurobiol Dis 2019; 134:104628. [PMID: 31669732 DOI: 10.1016/j.nbd.2019.104628] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/24/2019] [Accepted: 09/27/2019] [Indexed: 11/16/2022] Open
Abstract
Cardiorespiratory dysfunction during or after seizures may contribute to sudden unexpected death in epilepsy. Disruption of lower brainstem cardiorespiratory systems by seizures is postulated to impair respiratory and cardiac function. Here, we explore the effects of brainstem seizures and stimulation on cardiorespiratory function using a rat model of intrahippocampal 4-aminopyridine (4-AP)-induced acute recurrent seizures. Cardiac and respiratory monitoring together with local field potential recordings from hippocampus, contralateral parietal cortex and caudal dorsomedial brainstem, were conducted in freely moving adult male Wistar rats. Seizures were induced by intrahippocampal injection of 4-AP. Increased respiratory rate but unchanged heart rate occurred during hippocampal and secondarily generalized cortical seizures. Status epilepticus without brainstem seizures increased respiratory and heart rates, whereas status epilepticus with intermittent brainstem seizures induced repeated episodes of cardiorespiratory depression leading to death. Respiratory arrest occurred prior to asystole which was the terminal event. Phenytoin (100 mg/kg, intraperitoneal injection), administered after 4-AP intrahippocampal injection, terminated brainstem seizures and the associated cardiorespiratory depression, preventing death in five of six rats. Focal electrical stimulation of the caudal dorsomedial brainstem also suppressed cardiorespiratory rates. We conclude that in our model, brainstem seizures were associated with respiratory depression followed by cardiac arrest, and then death. We hypothesize this model shares mechanisms in common with the classic sudden unexpected death in epilepsy (SUDEP) syndrome associated with spontaneous seizures.
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Affiliation(s)
- Wanida Lertwittayanon
- Krembil Research Institute, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Department of Physiology, Prince of Songkla University, Hat Yai, Songkhla, Thailand; Research unit for EEG biomarkers of neuronal diseases, Prince of Songkla University, Hat Yai, Songkhla, Thailand
| | - Orrin Devinsky
- New York University Medical Center, Neurology, NY, New York, United States
| | - Peter L Carlen
- Krembil Research Institute, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Departments of Medicine (Neurology), Institute of Biomaterials and Biomedical Engineering, University of Toronto, Canada.
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Kalitzin S, Petkov G, Suffczynski P, Grigorovsky V, Bardakjian BL, Lopes da Silva F, Carlen PL. Epilepsy as a manifestation of a multistate network of oscillatory systems. Neurobiol Dis 2019; 130:104488. [DOI: 10.1016/j.nbd.2019.104488] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 06/03/2019] [Accepted: 06/04/2019] [Indexed: 12/18/2022] Open
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Jacobs D, Liu YH, Hilton T, Del Campo M, Carlen PL, Bardakjian BL. Classification of Scalp EEG States Prior to Clinical Seizure Onset. IEEE J Transl Eng Health Med 2019; 7:2000203. [PMID: 31497409 PMCID: PMC6726463 DOI: 10.1109/jtehm.2019.2926257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2018] [Revised: 05/13/2019] [Accepted: 06/12/2019] [Indexed: 11/07/2022]
Abstract
OBJECTIVE To investigate the feasibility of improving the performance of an EEG-based multistate classifier (MSC) previously proposed by our group. RESULTS Using the random forest (RF) classifiers on the previously reported dataset of patients, but with three improvements to classification logic, the specificity of our alarm algorithm improves from 82.4% to 92.0%, and sensitivity from 87.9% to 95.2%. DISCUSSION The MSC could be a useful approach for seizure-monitoring both in the clinic and at home. METHODS Three improvements to the MSC are described. Firstly, an additional check using RF outputs is made prior to alarm to confirm increasing probability of a seizure onset state. Secondly, a post-alarm detection horizon that accounts for the seizure state duration is implemented. Thirdly, the alarm decision window is kept constant.
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Affiliation(s)
- Daniel Jacobs
- 1Institute of Biomaterials and Biomedical Engineering, University of TorontoTorontoONM5S 3G9Canada
| | - Yuhan H Liu
- 2Department of Electrical and Computer EngineeringUniversity of TorontoTorontoONM5S 3G9Canada
| | - Trevor Hilton
- 1Institute of Biomaterials and Biomedical Engineering, University of TorontoTorontoONM5S 3G9Canada
| | - Martin Del Campo
- 3Department of Medicine (Neurology)Toronto Western HospitalTorontoONM5T 2S8Canada
| | - Peter L Carlen
- 1Institute of Biomaterials and Biomedical Engineering, University of TorontoTorontoONM5S 3G9Canada.,3Department of Medicine (Neurology)Toronto Western HospitalTorontoONM5T 2S8Canada.,4Krembil Research Institute, University Health NetworkTorontoONM5T 2S8Canada
| | - Berj L Bardakjian
- 1Institute of Biomaterials and Biomedical Engineering, University of TorontoTorontoONM5S 3G9Canada.,2Department of Electrical and Computer EngineeringUniversity of TorontoTorontoONM5S 3G9Canada
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Abstract
Controlling seizures remains a challenging issue for the medical community. To make progress, researchers need a way to extensively study seizure dynamics and investigate its underlying mechanisms. Acute seizure models are convenient, offer the ability to perform electrophysiological recordings, and can generate a large volume of electrographic seizure-like (ictal) events. The promising findings from acute seizure models can then be advanced to chronic epilepsy models and clinical trials. Thus, studying seizures in acute models that faithfully replicate the electrographic and dynamical signatures of a clinical seizure will be essential for making clinically relevant findings. Studying ictal events in acute seizure models prepared from human tissue is also important for making findings that are clinically relevant. The key focus in this paper is on the cortical 4-AP model due to its versatility in generating ictal events in both in vivo and in vitro studies, as well as in both mouse and human tissue. The methods in this paper will also describe an alternative method of seizure induction using the Zero-Mg2+ model and provide a detailed overview of the advantages and limitations of the epileptiform-like activity generated in the different acute seizure models. Moreover, by taking advantage of commercially available optogenetic mouse strains, a brief (30 ms) light pulse can be used to trigger an ictal event identical to those occurring spontaneously. Similarly, 30 - 100 ms puffs of neurotransmitters (Gamma-Amino Butyric Acid or glutamate) can be applied to the human tissue to trigger ictal events that are identical to those occurring spontaneously. The ability to trigger ictal events on-demand in acute seizure models offers the newfound ability to observe the exact sequence of events that underlie seizure initiation dynamics and efficiently evaluate potential anti-seizure therapies.
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Affiliation(s)
- Michael Chang
- Division of Fundamental Neurobiology, Krembil Research Institute; Institute of Medical Science, Faculty of Medicine, University of Toronto
| | - Suzie Dufour
- Division of Fundamental Neurobiology, Krembil Research Institute; Institute of Biomaterials and Biomedical Engineering, University of Toronto
| | - Peter L Carlen
- Division of Fundamental Neurobiology, Krembil Research Institute; Institute of Medical Science, Faculty of Medicine, University of Toronto; Institute of Biomaterials and Biomedical Engineering, University of Toronto; Division of Neurology, Department of Medicine, University of Toronto; Department of Physiology, University of Toronto
| | - Taufik A Valiante
- Division of Fundamental Neurobiology, Krembil Research Institute; Institute of Medical Science, Faculty of Medicine, University of Toronto; Institute of Biomaterials and Biomedical Engineering, University of Toronto; Division of Neurosurgery, Department of Surgery, University of Toronto;
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Wennberg R, Maurice C, Carlen PL, Garcia Dominguez L. Pilomotor seizures marked by infraslow activity and acetazolamide responsiveness. Ann Clin Transl Neurol 2019; 6:167-173. [PMID: 30656195 PMCID: PMC6331207 DOI: 10.1002/acn3.695] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 10/19/2018] [Indexed: 12/02/2022] Open
Abstract
A patient with pilomotor seizures post anti‐LGI1 limbic encephalitis, refractory to immunotherapy and anti‐epileptic drugs, was investigated with electroencephalography and magnetoencephalography. Seizures occurred daily (14.9 ± 4.9/day), with catamenial exacerbation, inducible by hyperventilation. Anterior temporal ictal onsets were heralded (by ~15 sec) by high amplitude ipsilateral electromagnetic infraslow activity. The catamenial/ventilatory sensitivity and the infraslow activity (reflecting glial depolarization) suggested an ionic, CO2/pH‐related glioneuronal mechanism. Furosemide decreased seizure frequency by ~33%. Acetazolamide led to immediate seizure freedom, but lost efficacy with daily treatment. A cycling acetazolamide regimen (2 days on, 4 days off) plus low‐dose topiramate maintained >95% reduction (0.5 ± 0.9/day) in seizures.
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Affiliation(s)
- Richard Wennberg
- Krembil Brain InstituteDivision of NeurologyUniversity Health NetworkUniversity of TorontoTorontoCanada
- Mitchell Goldhar MEG UnitClinical Neurophysiology LaboratoryToronto Western HospitalUniversity of TorontoTorontoCanada
| | - Catherine Maurice
- Krembil Brain InstituteDivision of NeurologyUniversity Health NetworkUniversity of TorontoTorontoCanada
| | - Peter L. Carlen
- Krembil Brain InstituteDivision of NeurologyUniversity Health NetworkUniversity of TorontoTorontoCanada
| | - Luis Garcia Dominguez
- Krembil Brain InstituteDivision of NeurologyUniversity Health NetworkUniversity of TorontoTorontoCanada
- Mitchell Goldhar MEG UnitClinical Neurophysiology LaboratoryToronto Western HospitalUniversity of TorontoTorontoCanada
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30
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Ringuette D, Nauenberg J, Monnier PP, Carlen PL, Levi O. Data compression and improved registration for laser speckle contrast imaging of rodent brains. Biomed Opt Express 2018; 9:5615-5634. [PMID: 30460150 PMCID: PMC6238931 DOI: 10.1364/boe.9.005615] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 08/30/2018] [Accepted: 09/13/2018] [Indexed: 05/16/2023]
Abstract
Single-frame blood flow maps from laser speckle contrast imaging (LSCI) contain high spatiotemporal variation that obscures high spatial-frequency vascular features, making precise image registration for signal amplification challenging. In this work, novel bivariate standardized moment filters (BSMFs) were used to provide stable measures of vessel edge location, permitting more robust LSCI registration. Relatedly, BSMFs enabled the stable reconstruction of vessel edges from sparsely distributed blood flow map outliers, which were found to retain most of the temporal dynamics. Consequently, data discarding and BSMF-based reconstruction enable efficient real-time quantitative LSCI data compression. Smaller LSCI-kernels produced log-normal blood flow distributions, enhancing sparse-to-dense inference.
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Affiliation(s)
- Dene Ringuette
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
- Division of Fundamental Neurobiology, Toronto Western Research Institute, 60 Leonard Ave, Toronto, Ontario M5T 2S8,
Canada
| | - Jacob Nauenberg
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario, M5S 3G4,
Canada
| | - Philippe P. Monnier
- Division of Fundamental Neurobiology, Toronto Western Research Institute, 60 Leonard Ave, Toronto, Ontario M5T 2S8,
Canada
| | - Peter L. Carlen
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
- Division of Fundamental Neurobiology, Toronto Western Research Institute, 60 Leonard Ave, Toronto, Ontario M5T 2S8,
Canada
| | - Ofer Levi
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario, M5S 3G4,
Canada
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Jacobs D, Hilton T, del Campo M, Carlen PL, Bardakjian BL. Classification of Pre-Clinical Seizure States Using Scalp EEG Cross-Frequency Coupling Features. IEEE Trans Biomed Eng 2018; 65:2440-2449. [DOI: 10.1109/tbme.2018.2797919] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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32
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Bazzigaluppi P, Adams C, Koletar MM, Dorr A, Pikula A, Carlen PL, Stefanovic B. Oophorectomy Reduces Estradiol Levels and Long-Term Spontaneous Neurovascular Recovery in a Female Rat Model of Focal Ischemic Stroke. Front Mol Neurosci 2018; 11:338. [PMID: 30271324 PMCID: PMC6146137 DOI: 10.3389/fnmol.2018.00338] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 08/28/2018] [Indexed: 12/31/2022] Open
Abstract
Although epidemiological evidence suggests significant sex and gender-based differences in stroke risk and recovery, females have been widely under-represented in preclinical stroke research. The neurovascular sequelae of brain ischemia in females, in particular, are largely uncertain. We set out to address this gap by a multimodal in vivo study of neurovascular recovery from endothelin-1 model of cortical focal-stroke in sham vs. ovariectomized female rats. Three weeks post ischemic insult, sham operated females recapitulated the phenotype previously reported in male rats in this model, of normalized resting perfusion but sustained peri-lesional cerebrovascular hyperreactivity. In contrast, ovariectomized (Ovx) females showed reduced peri-lesional resting blood flow, and elevated cerebrovascular responsivity to hypercapnia in the peri-lesional and contra-lateral cortices. Electrophysiological recordings showed an attenuation of theta to low-gamma phase-amplitude coupling in the peri-lesional tissue of Ovx animals, despite relative preservation of neuronal power. Further, this chronic stage neuronal network dysfunction was inversely correlated with serum estradiol concentration. Our pioneering data demonstrate dramatic differences in spontaneous recovery in the neurovascular unit between Ovx and Sham females in the chronic stage of stroke, underscoring the importance of considering hormonal-dependent aspects of the ischemic sequelae in the development of novel therapeutic approaches and patient recruitment in clinical trials.
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Affiliation(s)
- Paolo Bazzigaluppi
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Conner Adams
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Margaret M Koletar
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Adrienne Dorr
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada
| | - Aleksandra Pikula
- Adult Vascular Neurology, Toronto Western Hospital, Toronto, ON, Canada
| | - Peter L Carlen
- Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Bojana Stefanovic
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
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33
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Bazzigaluppi P, Lake EM, Beckett TL, Koletar MM, Weisspapir I, Heinen S, Mester J, Lai A, Janik R, Dorr A, McLaurin J, Stanisz GJ, Carlen PL, Stefanovic B. Imaging the Effects of β-Hydroxybutyrate on Peri-Infarct Neurovascular Function and Metabolism. Stroke 2018; 49:2173-2181. [DOI: 10.1161/strokeaha.118.020586] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Affiliation(s)
- Paolo Bazzigaluppi
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Sunnybrook Research Institute, Toronto, Canada; Fundamental Neurobiology, Krembil Research Institute, Toronto, Canada (P.B., I.W., P.L.C.)
| | - Evelyn M. Lake
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - Tina L. Beckett
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - Margaret M. Koletar
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - Iliya Weisspapir
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Sunnybrook Research Institute, Toronto, Canada; Fundamental Neurobiology, Krembil Research Institute, Toronto, Canada (P.B., I.W., P.L.C.)
| | | | - James Mester
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Biological Sciences (J.M.)
| | - Aaron Lai
- Department of Laboratory Medicine and Pathobiology (A.L., J.M.)
| | - Rafal Janik
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
| | - Adrienne Dorr
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
| | - JoAnne McLaurin
- Department of Laboratory Medicine and Pathobiology (A.L., J.M.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
| | - Greg J. Stanisz
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
| | - Peter L. Carlen
- Sunnybrook Research Institute, Toronto, Canada; Fundamental Neurobiology, Krembil Research Institute, Toronto, Canada (P.B., I.W., P.L.C.)
| | - Bojana Stefanovic
- From the Physical Sciences Platform (P.B., E.M.L., T.L.B., M.M.K., I.W., J.M., R.J., A.D., G.J.S., B.S.)
- Department of Medical Biophysics (J.M., R.J., G.J.S., B.S.), University of Toronto, Canada
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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35
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Whyte-Fagundes P, Kurtenbach S, Zoidl C, Shestopalov VI, Carlen PL, Zoidl G. A Potential Compensatory Role of Panx3 in the VNO of a Panx1 Knock Out Mouse Model. Front Mol Neurosci 2018; 11:135. [PMID: 29780304 PMCID: PMC5946002 DOI: 10.3389/fnmol.2018.00135] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2018] [Accepted: 04/03/2018] [Indexed: 12/30/2022] Open
Abstract
Pannexins (Panx) are integral membrane proteins, with Panx1 being the best-characterized member of the protein family. Panx1 is implicated in sensory processing, and knockout (KO) animal models have become the primary tool to investigate the role(s) of Panx1 in sensory systems. Extending previous work from our group on primary olfaction, the expression patterns of Panxs in the vomeronasal organ (VNO), an auxiliary olfactory sense organ with a role in reproduction and social behavior, were compared. Using qRT-PCR and Immunohistochemistry (IHC), we confirmed the loss of Panx1, found similar Panx2 expression levels in both models, and a significant upregulation of Panx3 in mice with a global ablation of Panx1. Specifically, Panx3 showed upregulated expression in nerve fibers of the non-sensory epithelial layer in juvenile and adult KO mice and in the sensory layer of adults, which overlaps with Panx1 expression areas in WT populations. Since both social behavior and evoked ATP release in the VNO was not compromised in KO animals, we hypothesized that Panx3 could compensate for the loss of Panx1. This led us to compare Panx1 and Panx3 channels in vitro, demonstrating similar dye uptake and ATP release properties. Outcomes of this study strongly suggest that Panx3 may functionally compensate for the loss of Panx1 in the VNO of the olfactory system, ensuring sustained chemosensory processing. This finding extends previous reports on the upregulation of Panx3 in arterial walls and the skin of Panx1 KO mice, suggesting that roles of Panx1 warrant uncharacterized safeguarding mechanisms involving Panx3.
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Affiliation(s)
- Paige Whyte-Fagundes
- Department of Biology, York University, Toronto, ON, Canada.,Krembil Research Institute, University Health Network, Toronto, ON, Canada
| | - Stefan Kurtenbach
- Department of Biology, York University, Toronto, ON, Canada.,Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | | | - Valery I Shestopalov
- Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, United States
| | - Peter L Carlen
- Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Georg Zoidl
- Department of Biology, York University, Toronto, ON, Canada.,Krembil Research Institute, University Health Network, Toronto, ON, Canada.,Department of Psychology, York University, Toronto, ON, Canada
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36
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Bazzigaluppi P, Ebrahim Amini A, Weisspapir I, Stefanovic B, Carlen PL. Hungry Neurons: Metabolic Insights on Seizure Dynamics. Int J Mol Sci 2017; 18:ijms18112269. [PMID: 29143800 PMCID: PMC5713239 DOI: 10.3390/ijms18112269] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 10/24/2017] [Accepted: 10/26/2017] [Indexed: 12/18/2022] Open
Abstract
Epilepsy afflicts up to 1.6% of the population and the mechanisms underlying the appearance of seizures are still not understood. In past years, many efforts have been spent trying to understand the mechanisms underlying the excessive and synchronous firing of neurons. Traditionally, attention was pointed towards synaptic (dys)function and extracellular ionic species (dys)regulation. Recently, novel clinical and preclinical studies explored the role of brain metabolism (i.e., glucose utilization) of seizures pathophysiology revealing (in most cases) reduced metabolism in the inter-ictal period and increased metabolism in the seconds preceding and during the appearance of seizures. In the present review, we summarize the clinical and preclinical observations showing metabolic dysregulation during epileptogenesis, seizure initiation, and termination, and in the inter-ictal period. Recent preclinical studies have shown that 2-Deoxyglucose (2-DG, a glycolysis blocker) is a novel therapeutic approach to reduce seizures. Furthermore, we present initial evidence for the effectiveness of 2-DG in arresting 4-Aminopyridine induced neocortical seizures in vivo in the mouse.
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Affiliation(s)
- Paolo Bazzigaluppi
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
- Sunnybrook Research Institute, Medical Biophysics, Toronto, ON M4N 3M5, Canada.
| | - Azin Ebrahim Amini
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
- Institute of Biomaterials & Biomedical Engineering (IBBME), University of Toronto, Toronto, ON M5S 3G9, Canada.
| | - Iliya Weisspapir
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
| | - Bojana Stefanovic
- Sunnybrook Research Institute, Medical Biophysics, Toronto, ON M4N 3M5, Canada.
| | - Peter L Carlen
- Krembil Research Institute, Fundamental Neurobiology, Toronto, ON M5T 2S8, Canada.
- Department of Medicine & Physiology, and Institute of Biomaterials & Biomedical Engineering (IBBME), University of Toronto, Toronto, ON M5S 1A8, Canada.
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Bazzigaluppi P, Beckett TL, Koletar MM, Lai AY, Joo IL, Brown ME, Carlen PL, McLaurin J, Stefanovic B. Early-stage attenuation of phase-amplitude coupling in the hippocampus and medial prefrontal cortex in a transgenic rat model of Alzheimer's disease. J Neurochem 2017; 144:669-679. [PMID: 28777881 DOI: 10.1111/jnc.14136] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/27/2017] [Accepted: 07/26/2017] [Indexed: 01/21/2023]
Abstract
Alzheimer's disease (AD) is pathologically characterized by amyloid-β peptide (Aβ) accumulation, neurofibrillary tangle formation, and neurodegeneration. Preclinical studies on neuronal impairments associated with progressive amyloidosis have demonstrated some Aβ-dependent neuronal dysfunction including modulation of gamma-aminobutyric acid-ergic signaling. The present work focuses on the early stage of disease progression and uses TgF344-AD rats that recapitulate a broad repertoire of AD-like pathologies to investigate the neuronal network functioning using simultaneous intracranial recordings from the hippocampus (HPC) and the medial prefrontal cortex (mPFC), followed by pathological analyses of gamma-aminobutyric acid (GABAA ) receptor subunits α1, α5, and δ, and glutamic acid decarboxylases (GAD65 and GAD67). Concomitant to amyloid deposition and tau hyperphosphorylation, low-gamma band power was strongly attenuated in the HPC and mPFC of TgF344-AD rats in comparison to those in non-transgenic littermates. In addition, the phase-amplitude coupling of the neuronal networks in both areas was impaired, evidenced by decreased modulation of theta band phase on gamma band amplitude in TgF344-AD animals. Finally, the gamma coherence between HPC and mPFC was attenuated as well. These results demonstrate significant neuronal network dysfunction at an early stage of AD-like pathology. This network dysfunction precedes the onset of cognitive deficits and is likely driven by Aβ and tau pathologies. This article is part of the Special Issue "Vascular Dementia".
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Affiliation(s)
- Paolo Bazzigaluppi
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Fundamental Neurobiology, Krembil Research Institute, Toronto, Ontario, Canada
| | - Tina L Beckett
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Margaret M Koletar
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Aaron Y Lai
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Illsung L Joo
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Mary E Brown
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Peter L Carlen
- Fundamental Neurobiology, Krembil Research Institute, Toronto, Ontario, Canada
| | - JoAnne McLaurin
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada.,Biological Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada
| | - Bojana Stefanovic
- Physical Sciences, Sunnybrook Research Institute, Toronto, Ontario, Canada.,Department of Medical Biophysics, University of Toronto, Ontario, Canada
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38
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Chang M, Dian JA, Dufour S, Wang L, Moradi Chameh H, Ramani M, Zhang L, Carlen PL, Womelsdorf T, Valiante TA. Brief activation of GABAergic interneurons initiates the transition to ictal events through post-inhibitory rebound excitation. Neurobiol Dis 2017; 109:102-116. [PMID: 29024712 DOI: 10.1016/j.nbd.2017.10.007] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Revised: 09/12/2017] [Accepted: 10/08/2017] [Indexed: 12/14/2022] Open
Abstract
Activation of γ-aminobutyric acid (GABAA) receptors have been associated with the onset of epileptiform events. To investigate if a causal relationship exists between GABAA receptor activation and ictal event onset, we activated inhibitory GABAergic networks in the superficial layer (2/3) of the somatosensory cortex during hyperexcitable conditions using optogenetic techniques in mice expressing channelrhodopsin-2 in all GABAergic interneurons. We found that a brief 30ms light pulse reliably triggered either an interictal-like event (IIE) or ictal-like ("ictal") event in the in vitro cortical 4-Aminopyridine (4-AP) slice model. The link between light pulse and epileptiform event onset was lost following blockade of GABAA receptors with bicuculline methiodide. Additionally, recording the chronological sequence of events following a light pulse in a variety of configurations (whole-cell, gramicidin-perforated patch, and multi-electrode array) demonstrated an initial hyperpolarization followed by post-inhibitory rebound spiking and a subsequent slow depolarization at the transition to epileptiform activity. Furthermore, the light-triggered ictal events were independent of the duration or intensity of the initiating light pulse, suggesting an underlying regenerative mechanism. Moreover, we demonstrated that brief GABAA receptor activation can initiate ictal events in the in vivo 4-AP mouse model, in another common in vitro model of epileptiform activity, and in neocortical tissue resected from epilepsy patients. Our findings reveal that the synchronous activation of GABAergic interneurons is a robust trigger for ictal event onset in hyperexcitable cortical networks.
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Affiliation(s)
- Michael Chang
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Joshua A Dian
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON, Canada
| | - Suzie Dufour
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - Lihua Wang
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Homeira Moradi Chameh
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Meera Ramani
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada
| | - Liang Zhang
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada
| | - Peter L Carlen
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Division of Neurology, Department of Medicine, University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada
| | - Thilo Womelsdorf
- Department of Psychology, Vanderbilt University, Nashville, TN, USA
| | - Taufik A Valiante
- Division of Fundamental Neurobiology, Krembil Research Institute, Toronto, ON, Canada; Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada; Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, ON, Canada; Institute of Medical Science, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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Salam MT, Montandon G, Genov R, Devinsky O, Del Campo M, Carlen PL. Mortality with brainstem seizures from focal 4-aminopyridine-induced recurrent hippocampal seizures. Epilepsia 2017; 58:1637-1644. [PMID: 28691204 DOI: 10.1111/epi.13846] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/19/2017] [Indexed: 11/29/2022]
Abstract
OBJECTIVE Sudden unexplained death in epilepsy is the leading cause of death in young adult epilepsy patients, typically occurring during the early postictal period, presumably resulting from brainstem and cardiorespiratory dysfunction. We hypothesized that ictal discharges in the brainstem disrupt the cardiorespiratory network, causing mortality. To study this hypothesis, we chose an animal model comprising focal unilateral hippocampal injection of 4-aminopyridine (4-AP), which produced focal recurrent hippocampal seizures with secondary generalization in awake, behaving rats. METHODS We studied ictal and interictal intracranial electrographic activity (iEEG) in 23 rats implanted with a custom electrode array into the hippocampus, the contralateral cortex, and brainstem. The hippocampal electrodes contained a cannula to administer the potassium channel blocker and convulsant (4-AP). iEEG was recorded continuously before, during, and after seizures induced by 4-AP infusion into the hippocampus. RESULTS The control group (n = 5) was monitored for 2-3 months, and the weekly baseline iEEG recordings showed long-term stability. The low-dose group (1 μL 4-AP, 40 mm, n = 5) exhibited local electrographic seizures without spread to the contralateral cerebral cortex or brainstem. The high-dose group (5 μL 4-AP, 40 mm, n = 3) had several hippocampal electrographic seizures, which spread contralaterally and triggered brainstem discharges within 40 min, and were associated with violent motor seizures followed by dyspnea and respiratory arrest, with cortical and hippocampal iEEG flattening. The group that received high-dose 4-AP without brainstem implantation (n = 5) had similar seizure-related respiratory difficulties. Finally, five rats that received high-dose 4-AP without EEG recording also developed violent motor seizures with postictal respiratory arrest. Following visualized respiratory arrest in groups III, IV, and V, manual respiratory resuscitation was successful in five of 13 animals. SIGNIFICANCE These studies show that hippocampal seizure activity can spread or trigger brainstem epileptiform discharges that may cause mortality, possibly mediated by respiratory network dysfunction.
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Affiliation(s)
- Muhammad Tariqus Salam
- Krembil Research Institute, University of Toronto, Toronto, Ontario, Canada.,Departments of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada.,Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada
| | - Gaspard Montandon
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Roman Genov
- Departments of Electrical and Computer Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Orrin Devinsky
- Department of Neurology, New York University Medical Center, New York, New York, U.S.A
| | - Martin Del Campo
- Krembil Research Institute, University of Toronto, Toronto, Ontario, Canada
| | - Peter L Carlen
- Krembil Research Institute, University of Toronto, Toronto, Ontario, Canada.,Department of Physiology, University of Toronto, Toronto, Ontario, Canada
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40
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Ringuette D, Jeffrey MA, Dufour S, Carlen PL, Levi O. Continuous multi-modality brain imaging reveals modified neurovascular seizure response after intervention. Biomed Opt Express 2017; 8:873-889. [PMID: 28270990 PMCID: PMC5330586 DOI: 10.1364/boe.8.000873] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 12/05/2016] [Accepted: 12/19/2016] [Indexed: 05/28/2023]
Abstract
We developed a multi-modal brain imaging system to investigate the relationship between blood flow, blood oxygenation/volume, intracellular calcium and electrographic activity during acute seizure-like events (SLEs), both before and after pharmacological intervention. Rising blood volume was highly specific to SLE-onset whereas blood flow was more correlated with all eletrographic activity. Intracellular calcium spiked between SLEs and at SLE-onset with oscillation during SLEs. Modified neurovascular and ionic SLE responses were observed after intervention and the interval between SLEs became shorter and more inconsistent. Comparison of artery and vein pulsatile flow suggest proximal interference and greater vascular leakage prior to intervention.
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Affiliation(s)
- Dene Ringuette
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
| | - Melanie A. Jeffrey
- Division of Fundamental Neurobiology, Toronto Western Research Institute, 60 Leonard Ave, Toronto, Ontario M5T 2R1,
Canada
| | - Suzie Dufour
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
- Division of Fundamental Neurobiology, Toronto Western Research Institute, 60 Leonard Ave, Toronto, Ontario M5T 2R1,
Canada
| | - Peter L. Carlen
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
- Division of Fundamental Neurobiology, Toronto Western Research Institute, 60 Leonard Ave, Toronto, Ontario M5T 2R1,
Canada
| | - Ofer Levi
- The Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, Ontario, M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, University of Toronto, 10 King’s College Road, Toronto, Ontario, M5S 3G4,
Canada
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41
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Bazzigaluppi P, Weisspapir I, Stefanovic B, Leybaert L, Carlen PL. Astrocytic gap junction blockade markedly increases extracellular potassium without causing seizures in the mouse neocortex. Neurobiol Dis 2016; 101:1-7. [PMID: 28007587 DOI: 10.1016/j.nbd.2016.12.017] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 11/24/2016] [Accepted: 12/18/2016] [Indexed: 10/20/2022] Open
Abstract
Extracellular potassium concentration, [K+]o, is a major determinant of neuronal excitability. In the healthy brain, [K+]o levels are tightly controlled. During seizures, [K+]o increases up to 15mM and is thought to cause seizures due to its depolarizing effect. Although astrocytes have been suggested to play a key role in the redistribution (or spatial buffering) of excess K+ through Connexin-43 (Cx43)-based Gap Junctions (GJs), the relation between this dynamic regulatory process and seizure generation remains unknown. Here we contrasted the role of astrocytic GJs and hemichannels by studying the effect of GJ and hemichannel blockers on [K+]o regulation in vivo. [K+]o was measured by K+-sensitive microelectrodes. Neuronal excitability was estimated by local field potential (LFP) responses to forepaw stimulation and changes in the power of resting state activity. Starting at the baseline [K+]o level of 1.61±0.3mM, cortical microinjection of CBX, a broad spectrum connexin channel blocker, increased [K+]o to 11±3mM, Cx43 GJ/hemichannel blocker Gap27 increased it from 1.9±0.7 to 9±1mM. At these [K+]o levels, no seizures were observed. Cx43 hemichannel blockade with TAT-Gap19 increased [K+]o by only ~1mM. Microinjection of 4-aminopyridine, a known convulsant, increased [K+]o to ~10mM and induced spontaneously recurring seizures, whereas direct application of K+ did not trigger seizure activity. These findings are the first in vivo demonstration that astrocytic GJs are major determinants for the spatial buffering of [K+]o and that an increase in [K+]o alone does not trigger seizures in the neocortex.
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Affiliation(s)
- Paolo Bazzigaluppi
- Fundamental Neurobiology, Krembil Research Institute, University Health Network, M5T 2S8 Toronto, Ontario, Canada; Physical Sciences, Sunnybrook Research Institute, M4N 3M5 Toronto, Ontario, Canada.
| | - Iliya Weisspapir
- Fundamental Neurobiology, Krembil Research Institute, University Health Network, M5T 2S8 Toronto, Ontario, Canada
| | - Bojana Stefanovic
- Physical Sciences, Sunnybrook Research Institute, M4N 3M5 Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Ontario, Canada
| | - Luc Leybaert
- Department of Basic Medical Sciences, University of Ghent, 9000 Ghent, Belgium
| | - Peter L Carlen
- Fundamental Neurobiology, Krembil Research Institute, University Health Network, M5T 2S8 Toronto, Ontario, Canada
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42
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Machado R, Soltani N, Dufour S, Salam MT, Carlen PL, Genov R, Thompson M. Biofouling-Resistant Impedimetric Sensor for Array High-Resolution Extracellular Potassium Monitoring in the Brain. Biosensors (Basel) 2016; 6:E53. [PMID: 27754393 PMCID: PMC5192373 DOI: 10.3390/bios6040053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Revised: 09/28/2016] [Accepted: 09/30/2016] [Indexed: 02/02/2023]
Abstract
Extracellular potassium concentration, [K⁺]o, plays a fundamental role in the physiological functions of the brain. Studies investigating changes in [K⁺]o have predominantly relied upon glass capillary electrodes with K⁺-sensitive solution gradients for their measurements. However, such electrodes are unsuitable for taking spatio-temporal measurements and are limited by the surface area of their tips. We illustrate seizures invoked chemically and in optogenetically modified mice using blue light exposure while impedimetrically measuring the response. A sharp decrease of 1-2 mM in [K⁺]o before each spike has shown new physiological events not witnessed previously when measuring extracellular potassium concentrations during seizures in mice. We propose a novel approach that uses multichannel monolayer coated gold microelectrodes for in vivo spatio-temporal measurements of [K⁺]o in a mouse brain as an improvement to the conventional glass capillary electrode.
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Affiliation(s)
- Ruben Machado
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada.
- Toronto Western Research Institute, Fundamental Neurobiology Division, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada.
| | - Nima Soltani
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, ON M5S 3G4, Canada.
| | - Suzie Dufour
- Toronto Western Research Institute, Fundamental Neurobiology Division, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada.
| | - Muhammad Tariqus Salam
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, ON M5S 3G4, Canada.
| | - Peter L Carlen
- Toronto Western Research Institute, Fundamental Neurobiology Division, 60 Leonard Avenue, Toronto, ON M5T 2S8, Canada.
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada.
| | - Roman Genov
- Department of Electrical and Computer Engineering, University of Toronto, 10 King's College Road, Toronto, ON M5S 3G4, Canada.
| | - Michael Thompson
- Department of Chemistry, University of Toronto, 80 St. George Street, Toronto, ON M5S 3H6, Canada.
- Institute of Biomaterials & Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9, Canada.
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43
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Dian JA, Colic S, Chinvarun Y, Carlen PL, Bardakjian BL. Identification of brain regions of interest for epilepsy surgery planning using support vector machines. Annu Int Conf IEEE Eng Med Biol Soc 2016; 2015:6590-3. [PMID: 26737803 DOI: 10.1109/embc.2015.7319903] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
In patients with intractable epilepsy, surgical resection is a promising treatment; however, post surgical seizure freedom is contingent upon accurate identification of the seizure onset zone (SOZ). Identification of the SOZ in extratemporal epilepsy requires invasive intracranial EEG (iEEG) recordings as well as resource intensive and subjective analysis by epileptologists. Expert inspection yields inconsistent localization of the SOZ which leads to comparatively poor post surgical outcomes for patients. This study employs recordings from 6 patients undergoing resection surgery in order to develop an automated and scalable system for identifying regions of interest (ROIs). Leveraging machine learning techniques and features used for seizure detection, a classification system was trained and tested on patients with Engel class I to class IV outcomes, demonstrating superior performance in the class I patients. Further, classification using features based upon both high frequency and low frequency oscillations was best able to identify channels suited for resection. This study demonstrates a novel approach to ROI identification and provides a path for developing tools to improve outcomes in epilepsy surgery.
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44
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Sigal I, Koletar MM, Ringuette D, Gad R, Jeffrey M, Carlen PL, Stefanovic B, Levi O. Imaging brain activity during seizures in freely behaving rats using a miniature multi-modal imaging system. Biomed Opt Express 2016; 7:3596-3609. [PMID: 27699123 PMCID: PMC5030035 DOI: 10.1364/boe.7.003596] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 08/11/2016] [Accepted: 08/11/2016] [Indexed: 05/20/2023]
Abstract
We report on a miniature label-free imaging system for monitoring brain blood flow and blood oxygenation changes in awake, freely behaving rats. The device, weighing 15 grams, enables imaging in a ∼ 2 × 2 mm field of view with 4.4 μm lateral resolution and 1 - 8 Hz temporal sampling rate. The imaging is performed through a chronically-implanted cranial window that remains optically clear between 2 to > 6 weeks after the craniotomy. This imaging method is well suited for longitudinal studies of chronic models of brain diseases and disorders. In this work, it is applied to monitoring neurovascular coupling during drug-induced absence-like seizures 6 weeks following the craniotomy.
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Affiliation(s)
- Iliya Sigal
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, 10 King’s College Road, Toronto, ON M5S 3G4,
Canada
| | - Margaret M. Koletar
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5,
Canada
| | - Dene Ringuette
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
| | - Raanan Gad
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, 10 King’s College Road, Toronto, ON M5S 3G4,
Canada
| | - Melanie Jeffrey
- Krembil Research Institute, 60 Leonard Avenue, Toronto, ON M5T 2S1,
Canada
| | - Peter L. Carlen
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- Krembil Research Institute, 60 Leonard Avenue, Toronto, ON M5T 2S1,
Canada
| | - Bojana Stefanovic
- Sunnybrook Research Institute, 2075 Bayview Avenue, Toronto, ON M4N 3M5,
Canada
- Department of Medical Biophysics, University of Toronto, 2075 Bayview Avenue, Toronto, ON M4N 3M5,
Canada
| | - Ofer Levi
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, 164 College Street, Toronto, ON M5S 3G9,
Canada
- The Edward S. Rogers Sr. Department of Electrical and Computer Engineering, 10 King’s College Road, Toronto, ON M5S 3G4,
Canada
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45
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Ramani M, Mylvaganam S, Krawczyk M, Wang L, Zoidl C, Brien J, Reynolds JN, Kapur B, Poulter MO, Zoidl G, Carlen PL. Differential expression of astrocytic connexins in a mouse model of prenatal alcohol exposure. Neurobiol Dis 2016; 91:83-93. [DOI: 10.1016/j.nbd.2016.02.022] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 01/11/2016] [Accepted: 02/29/2016] [Indexed: 11/24/2022] Open
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Abstract
Seizure activity leads to increases in extracellular potassium concentration ([K[Formula: see text]]o), which can result in changes in neuronal passive and active membrane properties as well as in population activities. In this study, we examined how extracellular potassium modulates seizure activities using an acute 4-AP induced seizure model in the neocortex, both in vivo and in vitro. Moderately elevated [K[Formula: see text]]o up to 9[Formula: see text]mM prolonged seizure durations and shortened interictal intervals as well as depolarized the neuronal resting membrane potential (RMP). However, when [K[Formula: see text]]o reached higher than 9[Formula: see text]mM, seizure like events (SLEs) were blocked and neurons went into a depolarization-blocked state. Spreading depression was never observed as the blockade of ictal events could be reversed within 1-2[Formula: see text]min after the raised [K[Formula: see text]]o was changed back to control levels. This concentration-dependent dual effect of [K[Formula: see text]]o was observed using in vivo and in vitro mouse brain preparations as well as in human neocortical tissue resected during epilepsy surgery. Blocking the Ih current, mediated by hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, modulated the elevated [K[Formula: see text]]o influence on SLEs by promoting the high [K[Formula: see text]]o inhibitory actions. These results demonstrate biphasic actions of raised [K[Formula: see text]]o on neuronal excitability and seizure activity.
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Affiliation(s)
- Lihua Wang
- 1 Departments of Medicine (Neurology) and Physiology, University Health Network, University of Toronto, Toronto, M5T 2S8, Ontario, Canada
| | - Suzie Dufour
- 1 Departments of Medicine (Neurology) and Physiology, University Health Network, University of Toronto, Toronto, M5T 2S8, Ontario, Canada
| | - Taufik A Valiante
- 2 Division of Neurosurgery, Department of Surgery, University Health Network, University of Toronto, Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, M5T 2S8, Ontario, Canada
| | - Peter L Carlen
- 3 Departments of Medicine (Neurology) and Physiology, University Health Network, University of Toronto, Institute of Biomaterials and Biomedical Engineering University of Toronto, Toronto, M5T 2S8, Ontario, Canada
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47
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Krawczyk M, Ramani M, Dian J, Florez CM, Mylvaganam S, Brien J, Reynolds J, Kapur B, Zoidl G, Poulter MO, Carlen PL. Hippocampal hyperexcitability in fetal alcohol spectrum disorder: Pathological sharp waves and excitatory/inhibitory synaptic imbalance. Exp Neurol 2016; 280:70-9. [PMID: 26996134 DOI: 10.1016/j.expneurol.2016.03.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 02/29/2016] [Accepted: 03/13/2016] [Indexed: 01/01/2023]
Abstract
Prenatal alcohol exposure (PAE) can lead to long-lasting neurological alterations that may predispose individuals to seizures and neurobehavioral dysfunction. To date, there exists limited information regarding the underlying pathophysiological mechanisms. The hippocampal CA3 region generates excitatory population activity, called sharp waves (SPWs), that provide an ideal model to study perturbations in neuronal excitability at the network and cellular levels. In the present study, we utilized a mouse model of PAE and used dual extracellular and whole-cell patch-clamp recordings from CA3 hippocampal pyramidal cells to evaluate the effect of 1st trimester-equivalent ethanol exposure (10% v/v) on SPW activity and excitatory/inhibitory balance. We observed that PAE significantly altered in vitro SPW waveforms, with an increased duration and amplitude, when compared to controls. In addition, PAE slices exhibited reduced pharmacological inhibition by the GABA-A receptor antagonist bicuculline (BMI) on SPW activity, and increased population spike paired-pulse ratios, all indicative of network disinhibition within the PAE hippocampus. Evaluation of PAE CA3 pyramidal cell activity associated with SPWs, revealed increased action potential cell firing, which was accompanied by an imbalance of excitatory/inhibitory synaptic drive, shifted in favor of excitation. Moreover, we observed intrinsic changes in CA3 pyramidal activity in PAE animals, including increased burst firing and instantaneous firing rate. This is the first study to provide evidence for hippocampal dysfunction in the ability to maintain network homeostasis and underlying cellular hyperexcitability in a model of PAE. These circuit and cellular level alterations may contribute to the increased propensity for seizures and neurobehavioral dysfunction observed in patients with a history of PAE.
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Affiliation(s)
- Michal Krawczyk
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada.
| | - Meera Ramani
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - Josh Dian
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - Carlos M Florez
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - Shanthini Mylvaganam
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada
| | - James Brien
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - James Reynolds
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, Canada
| | - Bhushan Kapur
- Division of Clinical Pharmacology & Toxicology, The Hospital for Sick Children, Toronto, ON, Canada
| | - Georg Zoidl
- Department of Biology, York University, Toronto, ON, Canada; Department of Psychology, York University, Toronto, ON, Canada
| | - Michael O Poulter
- Robarts Research Institute and Department of Physiology and Pharmacology, University of Western Ontario, London, ON, Canada
| | - Peter L Carlen
- Division of Fundamental Neurobiology, Toronto Western Research Institute, UHN, Toronto, ON, Canada; Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada; Department of Physiology, University of Toronto, Toronto, ON, Canada
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Guirgis M, Chinvarun Y, Carlen PL, Bardakjian BL. The role of delta-modulated high frequency oscillations in seizure state classification. Annu Int Conf IEEE Eng Med Biol Soc 2015; 2013:6595-8. [PMID: 24111254 DOI: 10.1109/embc.2013.6611067] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
High frequency oscillations (HFOs), which collectively refer to ripples (80-200 Hz) and fast ripples (>200 Hz), have been implicated as key players in epileptogenesis. However, their presence alone is not in and of itself indicative of a pathological brain state. Rather, spatial origins as well as coexistence with other neural rhythms are essential components in defining pathological HFOs. This study investigates how the phase of the delta rhythm (0.5-4 Hz) modulates the amplitude of HFOs during a seizure episode. Seven seizures recorded from three patients presenting with intractable temporal lobe epilepsy were obtained via intracranial electroencephalography (iEEG) from a 64-electrode grid. Delta modulation of the HFO rhythms was found to emerge at seizure onset and termination regardless of the dynamics present within the seizure episode itself. Moreover, the differences between delta modulating the ripple or fast ripple may be due to the sleep stage of the patient when the seizures were being recorded. Further studies exploring how this modulation changes in space across the grid may also highlight additional properties of this phenomenon. Its temporal pattern suggests that it is a potential iEEG-based biomarker for seizure state classification.
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Florez CM, Lukankin V, Sugumar S, McGinn R, Zhang ZJ, Zhang L, Carlen PL. Hypoglycemia-induced alterations in hippocampal intrinsic rhythms: Decreased inhibition, increased excitation, seizures and spreading depression. Neurobiol Dis 2015; 82:213-225. [PMID: 26093168 DOI: 10.1016/j.nbd.2015.06.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2014] [Revised: 06/09/2015] [Accepted: 06/12/2015] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Seizures are the most common clinical presentation of severe hypoglycemia, usually as a side effect of insulin treatment for juvenile onset type 1 diabetes mellitus and advanced type 2 diabetes. We used the mouse thick hippocampal slice preparation to study the pathophysiology of hypoglycemia-induced seizures and the effects of severe glucose depletion on the isolated hippocampal rhythms from the CA3 circuitry. METHODS AND RESULTS Dropping the glucose perfusate concentration from the standard 10 mM to 1 mM produced epileptiform activity in 14/16 of the slices. Seizure-like events (SLEs) originated in the CA3 region and then spread into the CA1 region. Following the SLE, a spreading-depression (SD)-like event occurred (12/16 slices) with irreversible synaptic failure in the CA1 region (8/12 slices). CA3 SD-like events followed ~30 s after the SD-like event in the CA1 region. Less commonly, SD-like events originated in the CA3 region (4/12). Additionally, prior to the onset of the SLE in the CA3 area, there was decreased GABA correlated baseline SPW activity (bSPW), while there was increased large-amplitude sharp wave (LASW) activity, thought to originate from synchronous pyramidal cell firing. CA3 pyramidal cells displayed progressive tonic depolarization prior to the seizure which was resistant to synaptic transmission blockade. The initiation of hypoglycemic seizures and SD was prevented by AMPA/kainate or NMDA receptor blockade. CONCLUSIONS Severe glucose depletion induces rapid changes initiated in the intrinsic CA3 rhythms of the hippocampus including depressed inhibition and enhanced excitation, which may underlie the mechanisms of seizure generation and delayed spreading depression.
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Affiliation(s)
- C M Florez
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada; Division of Fundamental Neurobiology, TWRI, UHN, Toronto, Canada
| | - V Lukankin
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada
| | - S Sugumar
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada
| | - R McGinn
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada
| | - Z J Zhang
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada
| | - L Zhang
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada
| | - P L Carlen
- Departments of Medicine (Neurology) and Physiology, University of Toronto, Toronto, Canada; Division of Fundamental Neurobiology, TWRI, UHN, Toronto, Canada.
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Guirgis M, Chinvarun Y, Del Campo M, Carlen PL, Bardakjian BL. Defining regions of interest using cross-frequency coupling in extratemporal lobe epilepsy patients. J Neural Eng 2015; 12:026011. [PMID: 25768723 DOI: 10.1088/1741-2560/12/2/026011] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
OBJECTIVE Clinicians identify seizure onset zones (SOZs) for resection in an attempt to localize the epileptogenic zone (EZ), which is the cortical tissue that is indispensible for seizure generation. An automated system is proposed to objectively localize this EZ by identifying regions of interest (ROIs). METHODS Intracranial electroencephalogram recordings were obtained from seven patients presenting with extratemporal lobe epilepsy and the interaction between neuronal rhythms in the form of phase-amplitude coupling was investigated. Modulation of the amplitude of high frequency oscillations (HFOs) by the phase of low frequency oscillations was measured by computing the modulation index (MI). Delta- (0.5-4 Hz) and theta- (4-8 Hz) modulation of HFOs (30-450 Hz) were examined across the channels of a 64-electrode subdural grid. Surrogate analysis was performed and false discovery rates were computed to determine the significance of the modulation observed. Mean MI values were subjected to eigenvalue decomposition (EVD) and channels defining the ROIs were selected based on the components of the eigenvector corresponding to the largest eigenvalue. ROIs were compared to the SOZs identified by two independent neurologists. Global coherence values were also computed. MAIN RESULTS MI was found to capture the seizure in time for six of seven patients and identified ROIs in all seven. Patients were found to have a poorer post-surgical outcome when the number of EVD-selected channels that were not resected increased. Moreover, in patients who experienced a seizure-free outcome (i.e., Engel Class I) all EVD-selected channels were found to be within the resected tissue or immediately adjacent to it. In these Engel Class I patients, delta-modulated HFOs were found to identify more of the channels in the resected tissue compared to theta-modulated HFOs. However, for the Engel Class IV patient, the delta-modulated HFOs did not identify any of the channels in the resected tissue suggesting that the resected tissue was not appropriate, which was also suggested by the Engel Class IV outcome. A sensitivity of 75.4% and a false positive rate of 15.6% were achieved using delta-modulated HFOs in an Engel Class I patient. SIGNIFICANCE LFO-modulated HFOs can be used to identify ROIs in extratemporal lobe patients. Moreover, delta-modulated HFOs may provide more accurate localization of the EZ. These ROIs may result in better surgical outcomes when used to compliment the SOZs identified by clinicians for resection.
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Affiliation(s)
- Mirna Guirgis
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, M5S 3G9, Canada
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