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Ndode-Ekane XE, Ali I, Gomez CS, Andrade P, Immonen R, Casillas-Espinosa P, Paananen T, Manninen E, Puhakka N, Smith G, Brady RD, Silva J, Braine E, Hudson M, Yamakawa GR, Jones NC, Shultz SR, Harris N, Wright DK, Gröhn O, Staba R, O’Brien TJ, Pitkänen A. Epilepsy phenotype and its reproducibility after lateral fluid percussion-induced traumatic brain injury in rats: Multicenter EpiBioS4Rx study project 1. Epilepsia 2024; 65:511-526. [PMID: 38052475 PMCID: PMC10922674 DOI: 10.1111/epi.17838] [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: 08/15/2023] [Revised: 11/21/2023] [Accepted: 11/27/2023] [Indexed: 12/07/2023]
Abstract
OBJECTIVE This study was undertaken to assess reproducibility of the epilepsy outcome and phenotype in a lateral fluid percussion model of posttraumatic epilepsy (PTE) across three study sites. METHODS A total of 525 adult male Sprague Dawley rats were randomized to lateral fluid percussion-induced brain injury (FPI) or sham operation. Of these, 264 were assigned to magnetic resonance imaging (MRI cohort, 43 sham, 221 traumatic brain injury [TBI]) and 261 to electrophysiological follow-up (EEG cohort, 41 sham, 220 TBI). A major effort was made to harmonize the rats, materials, equipment, procedures, and monitoring systems. On the 7th post-TBI month, rats were video-EEG monitored for epilepsy diagnosis. RESULTS A total of 245 rats were video-EEG phenotyped for epilepsy on the 7th postinjury month (121 in MRI cohort, 124 in EEG cohort). In the whole cohort (n = 245), the prevalence of PTE in rats with TBI was 22%, being 27% in the MRI and 18% in the EEG cohort (p > .05). Prevalence of PTE did not differ between the three study sites (p > .05). The average seizure frequency was .317 ± .725 seizures/day at University of Eastern Finland (UEF; Finland), .085 ± .067 at Monash University (Monash; Australia), and .299 ± .266 at University of California, Los Angeles (UCLA; USA; p < .01 as compared to Monash). The average seizure duration did not differ between UEF (104 ± 48 s), Monash (90 ± 33 s), and UCLA (105 ± 473 s; p > .05). Of the 219 seizures, 53% occurred as part of a seizure cluster (≥3 seizures/24 h; p >.05 between the study sites). Of the 209 seizures, 56% occurred during lights-on period and 44% during lights-off period (p > .05 between the study sites). SIGNIFICANCE The PTE phenotype induced by lateral FPI is reproducible in a multicenter design. Our study supports the feasibility of performing preclinical multicenter trials in PTE to increase statistical power and experimental rigor to produce clinically translatable data to combat epileptogenesis after TBI.
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Affiliation(s)
- Xavier Ekolle Ndode-Ekane
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Idrish Ali
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Cesar Santana Gomez
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, United States
| | - Pedro Andrade
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Riikka Immonen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Pablo Casillas-Espinosa
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Tomi Paananen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Eppu Manninen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Noora Puhakka
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Gregory Smith
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, United States
| | - Rhys D. Brady
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Juliana Silva
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Emma Braine
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Matt Hudson
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Glen R. Yamakawa
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Nigel C. Jones
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Sandy R. Shultz
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Neil Harris
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, United States
| | - David K. Wright
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Olli Gröhn
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
| | - Richard Staba
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, 90095, United States
| | - Terence J. O’Brien
- Department of Neuroscience, Monash University, Melbourne, Australia
- Department of Neurology, Alfred Health, Melbourne, Australia
- Department of Medicine, The Royal Melbourne Hospital, The University of Melbourne, Parkville, Australia
| | - Asla Pitkänen
- A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, PO Box 1627, FI-70211 Kuopio, Finland
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Bottom-Tanzer S, Corella S, Meyer J, Sommer M, Bolaños L, Murphy T, Quiñones S, Heiney S, Shtrahman M, Whalen M, Oren R, Higley MJ, Cardin JA, Noubary F, Armbruster M, Dulla C. Traumatic brain injury disrupts state-dependent functional cortical connectivity in a mouse model. Cereb Cortex 2024; 34:bhae038. [PMID: 38365273 DOI: 10.1093/cercor/bhae038] [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: 10/16/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 02/18/2024] Open
Abstract
Traumatic brain injury (TBI) is the leading cause of death in young people and can cause cognitive and motor dysfunction and disruptions in functional connectivity between brain regions. In human TBI patients and rodent models of TBI, functional connectivity is decreased after injury. Recovery of connectivity after TBI is associated with improved cognition and memory, suggesting an important link between connectivity and functional outcome. We examined widespread alterations in functional connectivity following TBI using simultaneous widefield mesoscale GCaMP7c calcium imaging and electrocorticography (ECoG) in mice injured using the controlled cortical impact (CCI) model of TBI. Combining CCI with widefield cortical imaging provides us with unprecedented access to characterize network connectivity changes throughout the entire injured cortex over time. Our data demonstrate that CCI profoundly disrupts functional connectivity immediately after injury, followed by partial recovery over 3 weeks. Examining discrete periods of locomotion and stillness reveals that CCI alters functional connectivity and reduces theta power only during periods of behavioral stillness. Together, these findings demonstrate that TBI causes dynamic, behavioral state-dependent changes in functional connectivity and ECoG activity across the cortex.
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Affiliation(s)
- Samantha Bottom-Tanzer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
- MD/PhD Program, Tufts University School of Medicine, Boston, MA 02111, United States
- Neuroscience Program, Tufts Graduate School of Biomedical Sciences, Boston, MA 02111, United States
| | - Sofia Corella
- Department of Pathology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
- MD/PhD Program, Case Western Reserve University School of Medicine, Cleveland, OH 44106, United States
| | - Jochen Meyer
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, United States
| | - Mary Sommer
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Luis Bolaños
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Timothy Murphy
- Department of Psychiatry, University of British Columbia, Vancouver, British Columbia, V6T 1Z4, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4
| | - Sadi Quiñones
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
- Neuroscience Program, Tufts Graduate School of Biomedical Sciences, Boston, MA 02111, United States
| | - Shane Heiney
- Iowa Neuroscience Institute, University of Iowa, Iowa City, IA 52242, United States
| | - Matthew Shtrahman
- Department of Neurosciences, University of California San Diego, La Jolla, CA 92093, United States
| | - Michael Whalen
- Department of Pediatrics, Harvard Medical School, Massachusetts General Hospital, Boston, MA 02115, United States
| | - Rachel Oren
- Department of Neuroscience, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, United States
- Interdepartmental Neuroscience Program, Yale School of Medicine, New Haven, CT 06510, United States
| | - Michael J Higley
- Department of Neuroscience, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, United States
| | - Jessica A Cardin
- Department of Neuroscience, Kavli Institute for Neuroscience, Yale School of Medicine, New Haven, CT 06510, United States
| | - Farzad Noubary
- Department of Health Sciences, Northeastern University, Boston, MA 02115, United States
| | - Moritz Armbruster
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
| | - Chris Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA 02111, United States
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Zhu J, Qiu W, Wei F, Wang Y, Wang Q, Ma W, Xiong H, Cui Y, Li X, Xu R, Lin Y. Reactive A1 Astrocyte-Targeted Nucleic Acid Nanoantiepileptic Drug Downregulating Adenosine Kinase to Rescue Endogenous Antiepileptic Pathway. ACS Appl Mater Interfaces 2023. [PMID: 37334941 DOI: 10.1021/acsami.3c03455] [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] [Indexed: 06/21/2023]
Abstract
Resistance to traditional antiepileptic drugs is a major challenge in chronic epilepsy treatment. MicroRNA-based gene therapy is a promising alternative but has demonstrated limited efficacy due to poor blood-brain barrier permeability, cellular uptake, and targeting efficiency. Adenosine is an endogenous antiseizure agent deficient in the epileptic brain due to elevated adenosine kinase (ADK) activity in reactive A1 astrocytes. We designed a nucleic acid nanoantiepileptic drug (tFNA-ADKASO@AS1) based on a tetrahedral framework nucleic acid (tFNA), carrying an antisense oligonucleotide targeting ADK (ADKASO) and A1 astrocyte-targeted peptide (AS1). This tFNA-ADKASO@AS1 construct effectively reduced brain ADK, increased brain adenosine, mitigated aberrant mossy fiber sprouting, and reduced the recurrent spontaneous epileptic spike frequency in a mouse model of chronic temporal lobe epilepsy. Further, the treatment did not induce any neurotoxicity or major organ damage. This work provides proof-of-concept for a novel antiepileptic drug delivery strategy and for endogenous adenosine as a promising target for gene-based modulation.
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Affiliation(s)
- Jianwei Zhu
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Wenqiao Qiu
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Fan Wei
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yangyang Wang
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Qiguang Wang
- Department of Neurosurgery, West China Hospital of Sichuan University, Chengdu 610041, P. R. China
| | - Wenjuan Ma
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P. R. China
- Sichuan Provincial Engineering Research Center of Oral Biomaterials, Chengdu, Sichuan 610041, China
| | - Huan Xiong
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yan Cui
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Xinda Li
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Ruxiang Xu
- Department of Neurosurgery, Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Yunfeng Lin
- State Key Laboratory of Oral Diseases National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, 610041, P. R. China
- Sichuan Provincial Engineering Research Center of Oral Biomaterials, Chengdu, Sichuan 610041, China
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4
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Gudenschwager-Basso EK, Shandra O, Volanth T, Patel DC, Kelly C, Browning JL, Wei X, Harris EA, Mahmutovic D, Kaloss AM, Correa FG, Decker J, Maharathi B, Robel S, Sontheimer H, VandeVord PJ, Olsen ML, Theus MH. Atypical Neurogenesis, Astrogliosis, and Excessive Hilar Interneuron Loss Are Associated with the Development of Post-Traumatic Epilepsy. Cells 2023; 12:1248. [PMID: 37174647 PMCID: PMC10177146 DOI: 10.3390/cells12091248] [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: 01/21/2023] [Revised: 04/02/2023] [Accepted: 04/11/2023] [Indexed: 05/15/2023] Open
Abstract
BACKGROUND Traumatic brain injury (TBI) remains a significant risk factor for post-traumatic epilepsy (PTE). The pathophysiological mechanisms underlying the injury-induced epileptogenesis are under investigation. The dentate gyrus-a structure that is highly susceptible to injury-has been implicated in the evolution of seizure development. METHODS Utilizing the murine unilateral focal control cortical impact (CCI) injury, we evaluated seizure onset using 24/7 EEG video analysis at 2-4 months post-injury. Cellular changes in the dentate gyrus and hilus of the hippocampus were quantified by unbiased stereology and Imaris image analysis to evaluate Prox1-positive cell migration, astrocyte branching, and morphology, as well as neuronal loss at four months post-injury. Isolation of region-specific astrocytes and RNA-Seq were performed to determine differential gene expression in animals that developed post-traumatic epilepsy (PTE+) vs. those animals that did not (PTE-), which may be associated with epileptogenesis. RESULTS CCI injury resulted in 37% PTE incidence, which increased with injury severity and hippocampal damage. Histological assessments uncovered a significant loss of hilar interneurons that coincided with aberrant migration of Prox1-positive granule cells and reduced astroglial branching in PTE+ compared to PTE- mice. We uniquely identified Cst3 as a PTE+-specific gene signature in astrocytes across all brain regions, which showed increased astroglial expression in the PTE+ hilus. CONCLUSIONS These findings suggest that epileptogenesis may emerge following TBI due to distinct aberrant cellular remodeling events and key molecular changes in the dentate gyrus of the hippocampus.
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Affiliation(s)
| | - Oleksii Shandra
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
- Department of Biomedical Engineering, Florida International University, Miami, FL 33199, USA
| | - Troy Volanth
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Dipan C. Patel
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Colin Kelly
- Translational Biology Medicine and Health Graduate Program, Blacksburg, VA 24061, USA
| | - Jack L. Browning
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
| | - Xiaoran Wei
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
| | - Elizabeth A. Harris
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
| | - Dzenis Mahmutovic
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | - Alexandra M. Kaloss
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
| | | | - Jeremy Decker
- Department of Biomedical Engineering and Mechanics, Blacksburg, VA 24061, USA
| | - Biswajit Maharathi
- Department of Neurology and Rehabilitation, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Stefanie Robel
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35233, USA
| | | | - Pamela J. VandeVord
- Department of Biomedical Engineering and Mechanics, Blacksburg, VA 24061, USA
| | | | - Michelle H. Theus
- Department of Biomedical Sciences and Pathobiology, Virginia Tech, Blacksburg, VA 24061, USA (E.A.H.)
- School of Neuroscience, Virginia Tech, Blacksburg, VA 24061, USA
- Center for Engineered Health, Viginia Tech, Blacksburg, VA 24061, USA
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5
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Kang YJ, Lee SH, Boychuk JA, Butler CR, Juras JA, Cloyd RA, Smith BN. Adult Born Dentate Granule Cell Mediated Upregulation of Feedback Inhibition in a Mouse Model of Traumatic Brain Injury. J Neurosci 2022; 42:7077-7093. [PMID: 36002261 PMCID: PMC9480876 DOI: 10.1523/jneurosci.2263-21.2022] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [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: 11/12/2021] [Revised: 08/09/2022] [Accepted: 08/11/2022] [Indexed: 11/21/2022] Open
Abstract
Post-traumatic epilepsy (PTE) and behavioral comorbidities frequently develop after traumatic brain injury (TBI). Aberrant neurogenesis of dentate granule cells (DGCs) after TBI may contribute to the synaptic reorganization that occurs in PTE, but how neurogenesis at different times relative to the injury contributes to feedback inhibition and recurrent excitation in the dentate gyrus is unknown. Thus, we examined whether DGCs born at different postnatal ages differentially participate in feedback inhibition and recurrent excitation in the dentate gyrus using the controlled cortical impact (CCI) model of TBI. Both sexes of transgenic mice expressing channelrhodopsin2 (ChR2) in postnatally born DGCs were used for optogenetic activation of three DGC cohorts: postnatally early born DGCs, or those born just before or after CCI. We performed whole-cell patch-clamp recordings from ChR2-negative, mature DGCs and parvalbumin-expressing basket cells (PVBCs) in hippocampal slices to determine whether optogenetic activation of postnatally born DGCs increases feedback inhibition and/or recurrent excitation in mice 8-10 weeks after CCI and whether PVBCs are targets of ChR2-positive DGCs. In the dentate gyrus ipsilateral to CCI, activation of ChR2-expressing DGCs born before CCI produced increased feedback inhibition in ChR2-negative DGCs and increased excitation in PVBCs compared with those from sham controls. This upregulated feedback inhibition was less prominent in DGCs born early in life or after CCI. Surprisingly, ChR2-positive DGC activation rarely evoked recurrent excitation in mature DGCs from any cohort. These results support that DGC birth date-related increased feedback inhibition in of DGCs may contribute to altered excitability after TBI.SIGNIFICANCE STATEMENT Dentate granule cells (DGCs) control excitability of the dentate gyrus through synaptic interactions with inhibitory GABAergic interneurons. Persistent changes in DGC synaptic connectivity develop after traumatic brain injury, contributing to hyperexcitability in post-traumatic epilepsy (PTE). However, the impact of DGC neurogenesis on synaptic reorganization, especially on inhibitory circuits, after brain injury is not adequately described. Here, upregulation of feedback inhibition in mature DGCs from male and female mice was associated with increased excitation of parvalbumin-expressing basket cells by postnatally born DGCs, providing novel insights into underlying mechanisms of altered excitability after brain injury. A better understanding of these inhibitory circuit changes can help formulate hypotheses for development of novel, evidence-based treatments for post-traumatic epilepsy by targeting birth date-specific subsets of DGCs.
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Affiliation(s)
- Young-Jin Kang
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Sang-Hun Lee
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
- Epilepsy Research Center, University of Kentucky, Lexington, Kentucky 40536
| | - Jeffery A Boychuk
- Epilepsy Research Center, University of Kentucky, Lexington, Kentucky 40536
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Corwin R Butler
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - J Anna Juras
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Ryan A Cloyd
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
| | - Bret N Smith
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Neuroscience, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
- Epilepsy Research Center, University of Kentucky, Lexington, Kentucky 40536
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, Kentucky 40536
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky 40536
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6
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Frankowski JC, Tierno A, Pavani S, Cao Q, Lyon DC, Hunt RF. Brain-wide reconstruction of inhibitory circuits after traumatic brain injury. Nat Commun 2022; 13:3417. [PMID: 35701434 PMCID: PMC9197933 DOI: 10.1038/s41467-022-31072-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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: 11/11/2021] [Accepted: 05/31/2022] [Indexed: 11/09/2022] Open
Abstract
Despite the fundamental importance of understanding the brain's wiring diagram, our knowledge of how neuronal connectivity is rewired by traumatic brain injury remains remarkably incomplete. Here we use cellular resolution whole-brain imaging to generate brain-wide maps of the input to inhibitory neurons in a mouse model of traumatic brain injury. We find that somatostatin interneurons are converted into hyperconnected hubs in multiple brain regions, with rich local network connections but diminished long-range inputs, even at areas not directly damaged. The loss of long-range input does not correlate with cell loss in distant brain regions. Interneurons transplanted into the injury site receive orthotopic local and long-range input, suggesting the machinery for establishing distant connections remains intact even after a severe injury. Our results uncover a potential strategy to sustain and optimize inhibition after traumatic brain injury that involves spatial reorganization of the direct inputs to inhibitory neurons across the brain.
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Affiliation(s)
- Jan C Frankowski
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Alexa Tierno
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA.
| | - Shreya Pavani
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Quincy Cao
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - David C Lyon
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Robert F Hunt
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA. .,Epilepsy Research Center, University of California, Irvine, CA, 92697, USA. .,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, 92697, USA. .,Center for the Neurobiology of Learning and Memory, University of California, Irvine, Irvine, CA, 92697, USA. .,Center for Neural Circuit Mapping, University of California, Irvine, Irvine, CA, 92697, USA.
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7
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Reddy DS, Golub VM, Ramakrishnan S, Abeygunaratne H, Dowell S, Wu X. A Comprehensive and Advanced Mouse Model of Post-Traumatic Epilepsy with Robust Spontaneous Recurrent Seizures. Curr Protoc 2022; 2:e447. [PMID: 35671160 DOI: 10.1002/cpz1.447] [Citation(s) in RCA: 10] [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] [Indexed: 01/24/2023]
Abstract
Traumatic brain injury (TBI) is a leading cause of epilepsy in military persons and civilians. Spontaneous recurrent seizures (SRSs) occur in the months or years following the injury, which is commonly referred to as post-traumatic epilepsy (PTE). Currently, there is no effective treatment or cure for PTE; therefore, there is a critical need to develop animal models to help further understand and assess mechanisms and interventions related to TBI-induced epilepsy. Despite many attempts to induce PTE in animals, success has been limited due to a lack of consistent SRSs after TBI. We present a comprehensive protocol to induce PTE after contusion brain injury in mice, which exhibit robust SRSs along with neurodegeneration and neuroinflammation. This article provides a complete set of protocols for injury, outcomes, troubleshooting, and data analysis. Our broad profiling of a TBI mouse reveals features of progressive, long-lasting epileptic activity, hippocampal sclerosis, and comorbid mood and memory deficits. Overall, the PTE mouse shows striking consistency in recapitulating major hallmark features of human PTE. This mouse model will be helpful in assessing mechanisms of and interventions for TBI-induced epileptogenesis, epilepsy, and neuropsychiatric dysfunction. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Inducing controlled cortical impact injuries Support Protocol: Creating the custom domed camp Basic Protocol 2: Recording long-term video-EEG signals Basic Protocol 3: Analyzing video-EEG recordings.
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Affiliation(s)
- Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, Texas.,Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, Texas
| | - Victoria M Golub
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Sreevidhya Ramakrishnan
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Department of Biomedical Engineering, College of Engineering, Texas A&M University, College Station, Texas
| | - Hasara Abeygunaratne
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Samantha Dowell
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Xin Wu
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas.,Institute of Pharmacology and Neurotherapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
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8
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Wirtshafter HS, Disterhoft JF. In Vivo Multi-Day Calcium Imaging of CA1 Hippocampus in Freely Moving Rats Reveals a High Preponderance of Place Cells with Consistent Place Fields. J Neurosci 2022; 42:4538-4554. [PMID: 35501152 PMCID: PMC9172072 DOI: 10.1523/jneurosci.1750-21.2022] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [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: 08/27/2021] [Revised: 04/15/2022] [Accepted: 04/19/2022] [Indexed: 11/21/2022] Open
Abstract
Calcium imaging using GCaMP indicators and miniature microscopes has been used to image cellular populations during long timescales and in different task phases, as well as to determine neuronal circuit topology and organization. Because the hippocampus (HPC) is essential for tasks of memory, spatial navigation, and learning, calcium imaging of large populations of HPC neurons can provide new insight on cell changes over time during these tasks. All reported HPC in vivo calcium imaging experiments have been done in mouse. However, rats have many behavioral and physiological experimental advantages over mice. In this paper, we present the first (to our knowledge) in vivo calcium imaging from CA1 HPC in freely moving male rats. Using the UCLA Miniscope, we demonstrate that, in rat, hundreds of cells can be visualized and held across weeks. We show that calcium events in these cells are highly correlated with periods of movement, with few calcium events occurring during periods without movement. We additionally show that an extremely large percent of cells recorded during a navigational task are place cells (77.3 ± 5.0%, surpassing the percent seen during mouse calcium imaging), and that these cells enable accurate decoding of animal position and can be held over days with consistent place fields in a consistent spatial map. A detailed protocol is included, and implications of these advancements on in vivo imaging and place field literature are discussed.SIGNIFICANCE STATEMENT In vivo calcium imaging in freely moving animals allows the visualization of cellular activity across days. In this paper, we present the first in vivo Ca2+ recording from CA1 hippocampus (HPC) in freely moving rats. We demonstrate that hundreds of cells can be visualized and held across weeks, and that calcium activity corresponds to periods of movement. We show that a high percentage (77.3 ± 5.0%) of imaged cells are place cells, and that these place cells enable accurate decoding and can be held stably over days with little change in field location. Because the HPC is essential for many tasks involving memory, navigation, and learning, imaging of large populations of HPC neurons can shed new insight on cellular activity changes and organization.
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Affiliation(s)
- Hannah S Wirtshafter
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
| | - John F Disterhoft
- Department of Neuroscience, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611
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9
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Boychuk JA, Butler CR, Smith KC, Halmos MB, Smith BN. Zolpidem Profoundly Augments Spared Tonic GABAAR Signaling in Dentate Granule Cells Ipsilateral to Controlled Cortical Impact Brain Injury in Mice. Front Syst Neurosci 2022; 16:867323. [PMID: 35694044 PMCID: PMC9178240 DOI: 10.3389/fnsys.2022.867323] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/05/2022] [Indexed: 11/18/2022] Open
Abstract
Type A GABA receptors (GABAARs) are pentameric combinations of protein subunits that give rise to tonic (ITonicGABA) and phasic (i.e., synaptic; ISynapticGABA) forms of inhibitory GABAAR signaling in the central nervous system. Remodeling and regulation of GABAAR protein subunits are implicated in a wide variety of healthy and injury-dependent states, including epilepsy. The present study undertook a detailed analysis of GABAAR signaling using whole-cell patch clamp recordings from mouse dentate granule cells (DGCs) in coronal slices containing dorsal hippocampus at 1–2 or 8–13 weeks after a focal, controlled cortical impact (CCI) or sham brain injury. Zolpidem, a benzodiazepine-like positive modulator of GABAARs, was used to test for changes in GABAAR signaling of DGCs due to its selectivity for α1 subunit-containing GABAARs. Electric charge transfer and statistical percent change were analyzed in order to directly compare tonic and phasic GABAAR signaling and to account for zolpidem’s ability to modify multiple parameters of GABAAR kinetics. We observed that baseline ITonicGABA is preserved at both time-points tested in DGCs ipsilateral to injury (Ipsi-DGCs) compared to DGCs contralateral to injury (Contra-DGCs) or after sham injury (Sham-DGCs). Interestingly, application of zolpidem resulted in modulation of ITonicGABA across groups, with Ipsi-DGCs exhibiting the greatest responsiveness to zolpidem. We also report that the combination of CCI and acute application of zolpidem profoundly augments the proportion of GABAAR charge transfer mediated by tonic vs. synaptic currents at both time-points tested, whereas gene expression of GABAAR α1, α2, α3, and γ2 subunits is unchanged at 8–13 weeks post-injury. Overall, this work highlights the shift toward elevated influence of tonic inhibition in Ipsi-DGCs, the impact of zolpidem on all components of inhibitory control of DGCs, and the sustained nature of these changes in inhibitory tone after CCI injury.
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Affiliation(s)
- Jeffery A Boychuk
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Cellular and Integrative Physiology, UT Health San Antonio, San Antonio, TX, United States
| | - Corwin R Butler
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, OR, United States
| | - Katalin Cs Smith
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
| | - Miklos B Halmos
- Department of Psychology, Georgia State University, Atlanta, GA, United States
| | - Bret N Smith
- Department of Physiology, University of Kentucky, Lexington, KY, United States
- Department of Neuroscience, University of Kentucky, Lexington, KY, United States
- Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY, United States
- Department of Biomedical Sciences, Colorado State University, Fort Collins, CO, United States
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10
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Golub VM, Reddy DS. Post-Traumatic Epilepsy and Comorbidities: Advanced Models, Molecular Mechanisms, Biomarkers, and Novel Therapeutic Interventions. Pharmacol Rev 2022; 74:387-438. [PMID: 35302046 PMCID: PMC8973512 DOI: 10.1124/pharmrev.121.000375] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [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] [Indexed: 12/11/2022] Open
Abstract
Post-traumatic epilepsy (PTE) is one of the most devastating long-term, network consequences of traumatic brain injury (TBI). There is currently no approved treatment that can prevent onset of spontaneous seizures associated with brain injury, and many cases of PTE are refractory to antiseizure medications. Post-traumatic epileptogenesis is an enduring process by which a normal brain exhibits hypersynchronous excitability after a head injury incident. Understanding the neural networks and molecular pathologies involved in epileptogenesis are key to preventing its development or modifying disease progression. In this article, we describe a critical appraisal of the current state of PTE research with an emphasis on experimental models, molecular mechanisms of post-traumatic epileptogenesis, potential biomarkers, and the burden of PTE-associated comorbidities. The goal of epilepsy research is to identify new therapeutic strategies that can prevent PTE development or interrupt the epileptogenic process and relieve associated neuropsychiatric comorbidities. Therefore, we also describe current preclinical and clinical data on the treatment of PTE sequelae. Differences in injury patterns, latency period, and biomarkers are outlined in the context of animal model validation, pathophysiology, seizure frequency, and behavior. Improving TBI recovery and preventing seizure onset are complex and challenging tasks; however, much progress has been made within this decade demonstrating disease modifying, anti-inflammatory, and neuroprotective strategies, suggesting this goal is pragmatic. Our understanding of PTE is continuously evolving, and improved preclinical models allow for accelerated testing of critically needed novel therapeutic interventions in military and civilian persons at high risk for PTE and its devastating comorbidities.
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Affiliation(s)
- Victoria M Golub
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, Texas
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11
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Gupta A, Dovek L, Proddutur A, Elgammal FS, Santhakumar V. Long-Term Effects of Moderate Concussive Brain Injury During Adolescence on Synaptic and Tonic GABA Currents in Dentate Granule Cells and Semilunar Granule Cells. Front Neurosci 2022; 16:800733. [PMID: 35360164 PMCID: PMC8964009 DOI: 10.3389/fnins.2022.800733] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Accepted: 01/27/2022] [Indexed: 01/27/2023] Open
Abstract
Progressive physiological changes in the hippocampal dentate gyrus circuits following traumatic brain injury (TBI) contribute to temporal evolution of neurological sequelae. Although early posttraumatic changes in dentate synaptic and extrasynaptic GABA currents have been reported, and whether they evolve over time and remain distinct between the two projection neuron classes, granule cells and semilunar granule cells, have not been evaluated. We examined long-term changes in tonic GABA currents and spontaneous inhibitory postsynaptic currents (sIPSCs) and in dentate projection neurons 3 months after moderate concussive fluid percussion injury (FPI) in adolescent rats. Granule cell tonic GABA current amplitude remained elevated up to 1 month after FPI, but decreased to levels comparable with age-matched controls by 3 months postinjury. Granule cell sIPSC frequency, which we previously reported to be increased 1 week after FPI, remained higher than in age-matched controls at 1 month and was significantly reduced 3 months after FPI. In semilunar granule cells, tonic GABA current amplitude and sIPSC frequency were not different from controls 3 months after FPI, which contrast with decreases observed 1 week after injury. The switch in granule cell inhibitory inputs from early increase to subsequent decrease could contribute to the delayed emergence of cognitive deficits and seizure susceptibility after brain injury.
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Affiliation(s)
- Akshay Gupta
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States,Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Laura Dovek
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Archana Proddutur
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States,Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States
| | - Fatima S. Elgammal
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States
| | - Vijayalakshmi Santhakumar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers New Jersey Medical School, Newark, NJ, United States,Department of Molecular, Cell and Systems Biology, University of California, Riverside, Riverside, CA, United States,*Correspondence: Vijayalakshmi Santhakumar,
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12
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Burns TF, Rajan R. Temporal activity patterns of layer II and IV rat barrel cortex neurons in healthy and injured conditions. Physiol Rep 2022; 10:e15155. [PMID: 35194970 PMCID: PMC8864447 DOI: 10.14814/phy2.15155] [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] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 11/21/2021] [Accepted: 12/10/2021] [Indexed: 06/14/2023] Open
Abstract
Neurons are known to encode information not just by how frequently they fire, but also at what times they fire. However, characterizations of temporal encoding in sensory cortices under conditions of health and injury are limited. Here we characterized and compared the stimulus-evoked activity of 1210 online-sorted units in layers II and IV of rat barrel cortex under healthy and diffuse traumatic brain injury (TBI) (caused by a weight-drop model) conditions across three timepoints post-injury: four days, two weeks, and eight weeks. Temporal activity patterns in the first 50 ms post-stimulus recording showed four categories of responses: no response or 1, 2, or 3 temporally-distinct response components, that is, periods of high unit activity separated by silence. The relative proportions of unit response categories were similar between layers II and IV in healthy conditions but not in early post-TBI conditions. For units with multiple response components, inter-component timings were reliable in healthy and late post-TBI conditions but disrupted by injury. Response component times typically shifted earlier with increasing stimulus intensity and this was more pronounced in layer IV than layer II. Surprisingly, injury caused a reversal of this trend and in the late post-TBI condition no stimulus intensity-dependence differences were observed between layers II and IV. We speculate this indicates a potential compensatory mechanism in response to injury. These results demonstrate how temporal encoding features maladapt or functionally recover differently in sensory cortex after TBI. Such maladaptation or functional recovery is layer-dependent, perhaps due to differences in thalamic input or local inhibitory neuronal makeup.
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Affiliation(s)
- Thomas F. Burns
- Biomedicine Discovery InstituteMonash UniversityVictoriaAustralia
| | - Ramesh Rajan
- Biomedicine Discovery InstituteMonash UniversityVictoriaAustralia
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13
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Abstract
Purinergic signaling is increasingly recognized to play a role during the generation of hyperexcitable networks in the brain. Among the purinergic receptors, the ionotropic ATP-gated P2X7 receptor has attracted particular attention as a possible drug target for epilepsy. P2X7 receptor expression is increased in the brain of experimental models of epilepsy and in patients and, P2X7 receptor antagonism modulates seizure severity and epilepsy development. To date, studies analyzing the role of the P2X7 receptor during epilepsy have mainly focused on temporal lobe epilepsy, the most common form of acquired epilepsy in adults which is particularly prone to drug refractoriness.Animal models of seizures and epilepsy are an essential tool in the identification of novel anticonvulsive and antiepileptogenic drug targets and much data demonstrating a role for the P2X7 receptor during epilepsy have been obtained by using these models. The aim of the present book chapter is to provide a detailed description of two commonly used mouse models of temporal lobe epilepsy, which are the intra-amygdala kainic acid model of status epilepticus and the controlled cortical impact model of traumatic brain injury. This chapter concludes with a brief description of how these models can be used to investigate the impact of targeting the P2X7 receptor on acute seizures, epilepsy development and established epilepsy .
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Affiliation(s)
- Mariana Alves
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
| | - Laura de Diego-Garcia
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland
- Department of Optometry and Vision, Faculty of Optics and Optometry, Complutense University of Madrid, Madrid, Spain
| | - Tobias Engel
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, University of Medicine and Health Sciences, Dublin, Ireland.
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14
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Golub VM, Reddy DS. Contusion brain damage in mice for modelling of post-traumatic epilepsy with contralateral hippocampus sclerosis: Comprehensive and longitudinal characterization of spontaneous seizures, neuropathology, and neuropsychiatric comorbidities. Exp Neurol 2021; 348:113946. [PMID: 34896334 DOI: 10.1016/j.expneurol.2021.113946] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 11/12/2021] [Accepted: 12/04/2021] [Indexed: 02/03/2023]
Abstract
Traumatic brain injury (TBI) is a leading cause of acquired epilepsy referred to as post-traumatic epilepsy (PTE), characterized by spontaneous recurrent seizures (SRS) that start in the months or years following TBI. There is a critical need to develop small animal models for advancing the neurotherapeutics of PTE, which accounts for 20% of all acquired epilepsy cases. Despite many previous attempts, there are few PTE models with demonstrated consistency or longitudinal incidence of SRS, a critical feature for creating models for investigation of novel therapeutics for preventing PTE. Over the past few years, we have made in-depth updates and several advances to our mouse model of TBI in which SRS consistently occurs upon 24/7 monitoring for 4 months. Here, we show that an advanced cortical contusion damage in mice elicits a chronic state of PTE with SRS and robust epileptiform activity, along with cognitive comorbidities. We observed SRS in 33% and 87% of moderate and severe injury cohorts, respectively. Though incidence was higher in the severe cohort, moderate injury elicited a robust epileptogenesis. Progressive neuronal damage, neurodegeneration, and inflammation signals were evident in many brain regions; comorbid behavior and cognitive deficits were observed for up to 4-months. SRS onset was correlated with the inception of interneuron loss after TBI. Contralateral hippocampal sclerosis was unique and well correlated with SRS, confirming a potential network basis for epileptogenesis. Collectively, this mouse model exhibits a number of hallmark TBI sequelae reminiscent of human PTE. This model provides a vital tool for probing molecular pathological mechanisms and therapeutic interventions for post-traumatic epileptogenesis. SIGNIFICANCE STATEMENT: TBI is a leading cause of post-traumatic epilepsy (PTE). Despite many attempts to create PTE in animals, success has been limited due to a lack of consistent spontaneous "epileptic" seizures after TBI. We present a comprehensive phenotype of PTE after contusion brain injury in mice, which exhibits robust spontaneous seizures along with neuronal loss, inflammation, and cognitive dysfunction. Our broad profiling of a TBI mouse reveals features of progressive, long-lasting epileptic activity, unique contralateral hippocampal sclerosis, and comorbid mood and memory deficits. The PTE mouse shows a striking consistency in recapitulating major pathological sequelae of human PTE. This mouse model will be helpful in assessing mechanisms and interventions for TBI-induced epilepsy and mood dysfunction.
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Affiliation(s)
- Victoria M Golub
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Doodipala Samba Reddy
- Department of Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M University Health Science Center, Bryan, TX, USA.
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15
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Frankowski JC, Foik AT, Tierno A, Machhor JR, Lyon DC, Hunt RF. Traumatic brain injury to primary visual cortex produces long-lasting circuit dysfunction. Commun Biol 2021; 4:1297. [PMID: 34789835 PMCID: PMC8599505 DOI: 10.1038/s42003-021-02808-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 01/08/2021] [Accepted: 10/25/2021] [Indexed: 01/20/2023] Open
Abstract
Primary sensory areas of the mammalian neocortex have a remarkable degree of plasticity, allowing neural circuits to adapt to dynamic environments. However, little is known about the effects of traumatic brain injury on visual circuit function. Here we used anatomy and in vivo electrophysiological recordings in adult mice to quantify neuron responses to visual stimuli two weeks and three months after mild controlled cortical impact injury to primary visual cortex (V1). We found that, although V1 remained largely intact in brain-injured mice, there was ~35% reduction in the number of neurons that affected inhibitory cells more broadly than excitatory neurons. V1 neurons showed dramatically reduced activity, impaired responses to visual stimuli and weaker size selectivity and orientation tuning in vivo. Our results show a single, mild contusion injury produces profound and long-lasting impairments in the way V1 neurons encode visual input. These findings provide initial insight into cortical circuit dysfunction following central visual system neurotrauma.
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Affiliation(s)
- Jan C. Frankowski
- grid.266093.80000 0001 0668 7243Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697 USA
| | - Andrzej T. Foik
- grid.413454.30000 0001 1958 0162Ophthalmic Biology Group, International Centre for Translational Eye Research, Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland
| | - Alexa Tierno
- grid.266093.80000 0001 0668 7243Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697 USA
| | - Jiana R. Machhor
- grid.266093.80000 0001 0668 7243Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697 USA
| | - David C. Lyon
- grid.266093.80000 0001 0668 7243Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697 USA
| | - Robert F. Hunt
- grid.266093.80000 0001 0668 7243Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697 USA
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16
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Carver CM, DeWitt HR, Stoja AP, Shapiro MS. Blockade of TRPC Channels Limits Cholinergic-Driven Hyperexcitability and Seizure Susceptibility After Traumatic Brain Injury. Front Neurosci 2021; 15:681144. [PMID: 34489621 PMCID: PMC8416999 DOI: 10.3389/fnins.2021.681144] [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: 03/16/2021] [Accepted: 06/28/2021] [Indexed: 12/17/2022] Open
Abstract
We investigated the contribution of excitatory transient receptor potential canonical (TRPC) cation channels to posttraumatic hyperexcitability in the brain 7 days following controlled cortical impact model of traumatic brain injury (TBI) to the parietal cortex in male adult mice. We investigated if TRPC1/TRPC4/TRPC5 channel expression is upregulated in excitatory neurons after TBI in contribution to epileptogenic hyperexcitability in key hippocampal and cortical circuits that have substantial cholinergic innervation. This was tested by measuring TRPC1/TRPC4/TRPC5 protein and messenger RNA (mRNA) expression, assays of cholinergic function, neuronal Ca2+ imaging in brain slices, and seizure susceptibility after TBI. We found region-specific increases in expression of TRPC1, TRPC4, and TRPC5 subunits in the hippocampus and cortex following TBI. The dentate gyrus, CA3 region, and cortex all exhibited robust upregulation of TRPC4 mRNA and protein. TBI increased cFos activity in dentate gyrus granule cells (DGGCs) and layer 5 pyramidal neurons both at the time of TBI and 7 days post-TBI. DGGCs displayed greater magnitude and duration of acetylcholine-induced rises in intracellular Ca2+ in brain slices from mice subjected to TBI. The TBI mice also exhibited greater seizure susceptibility in response to pentylenetetrazol-induced kindling. Blockade of TRPC4/TRPC5 channels with M084 reduced neuronal hyperexcitation and impeded epileptogenic progression of kindling. We observed that the time-dependent upregulation of TRPC4/TRPC5-containing channels alters cholinergic responses and activity of principal neurons acting to increase proexcitatory sensitivity. The underlying mechanism includes acutely decreased acetylcholinesterase function, resulting in greater Gq/11-coupled muscarinic receptor activation of TRPC channels. Overall, our evidence suggests that TBI-induced plasticity of TRPC channels strongly contributes to overt hyperexcitability and primes the hippocampus and cortex for seizures.
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Affiliation(s)
- Chase M Carver
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Haley R DeWitt
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Aiola P Stoja
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
| | - Mark S Shapiro
- Department of Cellular and Integrative Physiology, University of Texas Health San Antonio, San Antonio, TX, United States
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17
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Fronczak KM, Li Y, Henchir J, Dixon CE, Carlson SW. Reductions in Synaptic Vesicle Glycoprotein 2 Isoforms in the Cortex and Hippocampus in a Rat Model of Traumatic Brain Injury. Mol Neurobiol 2021; 58:6006-6019. [PMID: 34435329 PMCID: PMC8602666 DOI: 10.1007/s12035-021-02534-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [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: 04/02/2021] [Accepted: 08/15/2021] [Indexed: 11/25/2022]
Abstract
Traumatic brain injury (TBI) can produce lasting cognitive, emotional, and somatic difficulties that can impact quality of life for patients living with an injury. Impaired hippocampal function and synaptic alterations have been implicated in contributing to cognitive difficulties in experimental TBI models. In the synapse, neuronal communication is facilitated by the regulated release of neurotransmitters from docking presynaptic vesicles. The synaptic vesicle glycoprotein 2 (SV2) isoforms SV2A and SV2B play central roles in the maintenance of the readily releasable pool of vesicles and the coupling of calcium to the N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complex responsible for vesicle docking. Recently, we reported the findings of TBI-induced reductions in presynaptic vesicle density and SNARE complex formation; however, the effect of TBI on SV2 is unknown. To investigate this, rats were subjected to controlled cortical impact (CCI) or sham control surgery. Abundance of SV2A and SV2B were assessed at 1, 3, 7 and 14 days post-injury by immunoblot. SV2A and SV2B were reduced in the cortex at several time points and in the hippocampus at every time point assessed. Immunohistochemical staining and quantitative intensity measurements completed at 14 days post-injury revealed reduced SV2A immunoreactivity in all hippocampal subregions and reduced SV2B immunoreactivity in the molecular layer after CCI. Reductions in SV2A abundance and immunoreactivity occurred concomitantly with motor dysfunction and spatial learning and memory impairments in the 2 weeks post-injury. These findings provide novel evidence for the effect of TBI on SV2 with implications for impaired neurotransmission neurobehavioral dysfunction after TBI.
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Affiliation(s)
- Katherine M Fronczak
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - Youming Li
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - Jeremy Henchir
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - C Edward Dixon
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.,VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - Shaun W Carlson
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.
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18
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Faillot M, Chaillet A, Palfi S, Senova S. Rodent models used in preclinical studies of deep brain stimulation to rescue memory deficits. Neurosci Biobehav Rev 2021; 130:410-432. [PMID: 34437937 DOI: 10.1016/j.neubiorev.2021.08.012] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 08/10/2021] [Accepted: 08/13/2021] [Indexed: 11/28/2022]
Abstract
Deep brain stimulation paradigms might be used to treat memory disorders in patients with stroke or traumatic brain injury. However, proof of concept studies in animal models are needed before clinical translation. We propose here a comprehensive review of rodent models for Traumatic Brain Injury and Stroke. We systematically review the histological, behavioral and electrophysiological features of each model and identify those that are the most relevant for translational research.
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Affiliation(s)
- Matthieu Faillot
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Antoine Chaillet
- Laboratoire des Signaux et Systèmes (L2S-UMR8506) - CentraleSupélec, Université Paris Saclay, Institut Universitaire de France, France
| | - Stéphane Palfi
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France
| | - Suhan Senova
- Neurosurgery department, Henri Mondor University Hospital, APHP, DMU CARE, Université Paris Est Créteil, Mondor Institute for Biomedical Research, INSERM U955, Team 15, Translational Neuropsychiatry, France.
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19
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Abstract
Traumatic brain injury (TBI) is defined as an alteration in brain function or other evidence of brain pathology caused by an external force. When epilepsy develops following TBI, it is known as post-traumatic epilepsy (PTE). PTE occurs in a subset of patients suffering from different types and severities of TBI, occurs more commonly following severe injury, and greatly impacts the quality of life for patients recovering from TBI. Similar to other types of epilepsy, PTE is often refractory to drug treatment with standard anti-seizure drugs. No therapeutic approaches have proven successful in the clinic to prevent the development of PTE. Therefore, novel treatment strategies are needed to stop the development of PTE and improve the quality of life for patients after TBI. Interestingly, TBI represents an excellent clinical opportunity for intervention to prevent epileptogenesis as typically the time of initiation of epileptogenesis (i.e., TBI) is known, the population of at-risk patients is large, and animal models for preclinical studies of mechanisms and treatment targets are available. If properly identified and treated, there is a true opportunity to prevent epileptogenesis after TBI and stop seizures from ever happening. With that goal in mind, here we review previous attempts to prevent PTE both in animal studies and in humans, we examine how biomarkers could enable better-targeted therapeutics, and we discuss how genetic variation may predispose individuals to PTE. Finally, we highlight exciting new advances in the field that suggest that there may be novel approaches to prevent PTE that should be considered for further clinical development.
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Affiliation(s)
- Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, USA.
| | - Asla Pitkänen
- A. I. Virtanen Institute, University of Eastern Finland, 70 211, Kuopio, Finland.
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20
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Cloyd RA, Koren J, Abisambra JF, Smith BN. Effects of altered tau expression on dentate granule cell excitability in mice. Exp Neurol 2021; 343:113766. [PMID: 34029610 DOI: 10.1016/j.expneurol.2021.113766] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 05/05/2021] [Accepted: 05/19/2021] [Indexed: 12/18/2022]
Abstract
Tauopathies, including Alzheimer's disease, are characterized by progressive accumulation of hyperphosphorylated and pathologic tau protein in association with onset of cognitive and behavioral impairment. Tau pathology is also associated with increased susceptibility to seizures and epilepsy, with tau-/- mice showing seizure resistance in some epilepsy models. To better understand how tau pathology is related to neuronal excitability, we performed whole-cell patch-clamp electrophysiology in dentate gyrus granule cells of tau-/- and human-tau expressing, htau mice. The htau mouse is unique from other transgenic tau models in that the endogenous murine tau gene has been and replaced with readily phosphorylated human tau. We assessed several measures of neuronal excitability, including evoked action potential frequency and excitatory synaptic responses in dentate granule cells from tau-/-, htau, and non-transgenic control mice at 1.5, 4, and 9 months of age. Compared to age matched controls, dentate granule cells from both tau-/- and htau mice had a lower peak frequency of evoked action potentials and greater paired pulse facilitation, suggesting reduced neuronal excitability. Our results suggest that neuronal excitability is more strongly influenced by the absence of functional tau than by the presence of pathologic tau. These results also suggest that tau's effect on neuronal excitability is more complex than previously understood.
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Affiliation(s)
- Ryan A Cloyd
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA
| | - John Koren
- Department of Neuroscience & Center for Translational Research in Neurodegenerative Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Jose F Abisambra
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Neuroscience & Center for Translational Research in Neurodegenerative Diseases, University of Florida, Gainesville, FL 32610, USA
| | - Bret N Smith
- Department of Physiology, University of Kentucky College of Medicine, Lexington, KY 40536, USA; Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY 40536, USA.
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21
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Di Sapia R, Moro F, Montanarella M, Iori V, Micotti E, Tolomeo D, Wang KKW, Vezzani A, Ravizza T, Zanier ER. In-depth characterization of a mouse model of post-traumatic epilepsy for biomarker and drug discovery. Acta Neuropathol Commun 2021; 9:76. [PMID: 33902685 PMCID: PMC8073903 DOI: 10.1186/s40478-021-01165-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 03/19/2021] [Indexed: 12/11/2022] Open
Abstract
Post-traumatic epilepsy (PTE) accounts for 5% of all epilepsies and 10–20% of the acquired forms. The latency between traumatic brain injury (TBI) and epilepsy onset in high-risk patients offers a therapeutic window for intervention to prevent or improve the disease course. However, progress towards effective treatments has been hampered by the lack of sensitive prognostic biomarkers of PTE, and of therapeutic targets. There is therefore a pressing clinical need for preclinical PTE models suitable for biomarker discovery and drug testing. We characterized in-depth a model of severe TBI induced by controlled cortical impact evolving into PTE in CD1 adult male mice. To identify sensitive measures predictive of PTE development and severity, TBI mice were longitudinally monitored by video-electrocorticography (ECoG), examined by MRI, and tested for sensorimotor and cognitive deficits and locomotor activity. At the end of the video-ECoG recording mice were killed for brain histological analysis. PTE occurred in 58% of mice with frequent motor seizures (one seizure every other day), as determined up to 5 months post-TBI. The weight loss of PTE mice in 1 week after TBI correlated with the number of spontaneous seizures at 5 months. Moreover, the recovery rate of the sensorimotor deficit detected by the SNAP test before the predicted time of epilepsy onset was significantly lower in PTE mice than in those without epilepsy. Neuroscore, beam walk and cognitive deficit were similar in all TBI mice. The increase in the contusion volume, the volume of forebrain regions contralateral to the lesioned hemisphere and white matter changes over time assessed by MRI were similar in PTE and no-PTE mice. However, brain histology showed a more pronounced neuronal cell loss in the cortex and hippocampus contralateral to the injured hemisphere in PTE than in no-PTE mice. The extensive functional and neuropathological characterization of this TBI model, provides a tool to identify sensitive measures of epilepsy development and severity clinically useful for increasing PTE prediction in high-risk TBI patients. The high PTE incidence and spontaneous seizures frequency in mice provide an ideal model for biomarker discovery and for testing new drugs.
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22
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Sharma S, Tiarks G, Haight J, Bassuk AG. Neuropathophysiological Mechanisms and Treatment Strategies for Post-traumatic Epilepsy. Front Mol Neurosci 2021; 14:612073. [PMID: 33708071 PMCID: PMC7940684 DOI: 10.3389/fnmol.2021.612073] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [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: 09/30/2020] [Accepted: 01/26/2021] [Indexed: 12/11/2022] Open
Abstract
Traumatic brain injury (TBI) is a leading cause of death in young adults and a risk factor for acquired epilepsy. Severe TBI, after a period of time, causes numerous neuropsychiatric and neurodegenerative problems with varying comorbidities; and brain homeostasis may never be restored. As a consequence of disrupted equilibrium, neuropathological changes such as circuit remodeling, reorganization of neural networks, changes in structural and functional plasticity, predisposition to synchronized activity, and post-translational modification of synaptic proteins may begin to dominate the brain. These pathological changes, over the course of time, contribute to conditions like Alzheimer disease, dementia, anxiety disorders, and post-traumatic epilepsy (PTE). PTE is one of the most common, devastating complications of TBI; and of those affected by a severe TBI, more than 50% develop PTE. The etiopathology and mechanisms of PTE are either unknown or poorly understood, which makes treatment challenging. Although anti-epileptic drugs (AEDs) are used as preventive strategies to manage TBI, control acute seizures and prevent development of PTE, their efficacy in PTE remains controversial. In this review, we discuss novel mechanisms and risk factors underlying PTE. We also discuss dysfunctions of neurovascular unit, cell-specific neuroinflammatory mediators and immune response factors that are vital for epileptogenesis after TBI. Finally, we describe current and novel treatments and management strategies for preventing PTE.
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Affiliation(s)
- Shaunik Sharma
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Grant Tiarks
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Joseph Haight
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
| | - Alexander G Bassuk
- Medical Laboratories, Department of Pediatrics, University of Iowa, Iowa City, IA, United States
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23
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Carlson SW, Yan HQ, Li Y, Henchir J, Ma X, Young MS, Ikonomovic MD, Dixon CE. Differential Regional Responses in Soluble Monomeric Alpha Synuclein Abundance Following Traumatic Brain Injury. Mol Neurobiol 2021; 58:362-374. [PMID: 32948930 PMCID: PMC7704579 DOI: 10.1007/s12035-020-02123-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [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: 06/11/2020] [Accepted: 09/05/2020] [Indexed: 12/14/2022]
Abstract
Alpha synuclein (α-synuclein) is a neuronal protein found predominately in presynaptic terminals. While the pathological effect of α-synuclein aggregates has been a topic of intense study in several neurodegenerative conditions, less attention has been placed on changes in monomeric α-synuclein and related physiological consequences on neuronal function. A growing body of evidence supports an important physiological role of α-synuclein in neurotransmission. In the context of traumatic brain injury (TBI), we hypothesized that the regional abundance of soluble monomeric α-synuclein is altered over a chronic time period post-injury. To this end, we evaluated α-synuclein in the cortex, hippocampus, and striatum of adult rats at 6 h, 1 day, 1, 2, 4, and 8 weeks after controlled cortical impact (CCI) injury. Western blot analysis demonstrated decreased levels of monomer α-synuclein protein in the ipsilateral hippocampus at 6 h, 1 day, 1, 2, and 8 weeks, as well as in the ipsilateral cortex at 1 and 2 weeks and in the ipsilateral striatum at 6 h after CCI compared with sham animals. Immunohistochemical analysis revealed lower α-synuclein and a modest reduction in synaptophysin staining in the ipsilateral hippocampus at 1 week after CCI compared with sham animals, with no evidence of intracellular or extracellular α-synuclein aggregates. Collectively, these findings demonstrate that monomeric α-synuclein protein abundance in the hippocampus is reduced over an extensive (acute-to-chronic) post-injury interval. This deficit may contribute to the chronically impaired neurotransmission known to occur after TBI.
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Affiliation(s)
- S W Carlson
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - H Q Yan
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - Y Li
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - J Henchir
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - X Ma
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - M S Young
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA
| | - M D Ikonomovic
- Neurology, University of Pittsburgh, 200 Lothrop Street, Pittsburgh, PA, 15261, USA
- VA Pittsburgh Healthcare System, Pittsburgh, PA, USA
| | - C E Dixon
- Neurological Surgery, University of Pittsburgh, 4401 Penn Avenue, Pittsburgh, PA, 15224, USA.
- VA Pittsburgh Healthcare System, Pittsburgh, PA, USA.
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24
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Mosini AC, Calió ML, Foresti ML, Valeriano RPS, Garzon E, Mello LE. Modeling of post-traumatic epilepsy and experimental research aimed at its prevention. ACTA ACUST UNITED AC 2020; 54:e10656. [PMID: 33331416 PMCID: PMC7747873 DOI: 10.1590/1414-431x202010656] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [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: 08/10/2020] [Accepted: 10/29/2020] [Indexed: 02/06/2023]
Abstract
Research on the prevention of post-traumatic epilepsy (PTE) has seen remarkable advances regarding its physiopathology in recent years. From the search for biomarkers that might be used to indicate individual susceptibility to the development of new animal models and the investigation of new drugs, a great deal of knowledge has been amassed. Various groups have concentrated efforts in generating new animal models of traumatic brain injury (TBI) in an attempt to provide the means to further produce knowledge on the subject. Here we forward the hypothesis that restricting the search of biomarkers and of new drugs to prevent PTE by using only a limited set of TBI models might hamper the understanding of this relevant and yet not preventable medical condition.
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Affiliation(s)
- A C Mosini
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil.,Associação Brasileira de Epilepsia, São Paulo, SP, Brasil
| | - M L Calió
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil
| | - M L Foresti
- Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro, RJ, Brasil
| | - R P S Valeriano
- Divisão de Clínica Neurológica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - E Garzon
- Divisão de Clínica Neurológica, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil
| | - L E Mello
- Departamento de Fisiologia, Universidade Federal de São Paulo, São Paulo, SP, Brasil.,Instituto D'Or de Pesquisa e Ensino, Rio de Janeiro, RJ, Brasil
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25
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Szu JI, Patel DD, Chaturvedi S, Lovelace JW, Binder DK. Modulation of posttraumatic epileptogenesis in aquaporin-4 knockout mice. Epilepsia 2020; 61:1503-1514. [PMID: 32484924 DOI: 10.1111/epi.16551] [Citation(s) in RCA: 8] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2019] [Revised: 05/05/2020] [Accepted: 05/05/2020] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine the role of aquaporin-4 (AQP4) in posttraumatic epileptogenesis using long-term video-electroencephalographic (vEEG) recordings. Here, differences in EEG were analyzed between wild-type (WT) and AQP4 knockout (KO) mice and between mice with and without posttraumatic epilepsy (PTE). METHODS WT and AQP4 KO mice were subjected to a single controlled cortical impact traumatic brain injury (TBI) in the frontal cortex, and vEEG was recorded in the ipsilateral hippocampus at 14, 30, 60, and 90 days postinjury (dpi). Intrahippocampal electrical stimulation was also used to assess electrographic seizure threshold and electrographic seizure duration (ESD). RESULTS The mean seizure frequency per day for WT mice was 0.07 ± 0.07, 0.11 ± 0.07, 0.26 ± 0.13, and 0.12 ± 0.10 at 14, 30, 60, and 90 dpi, respectively. The mean seizure frequency per day for AQP4 KO mice was 0.45 ± 0.27, 0.29 ± 0.12, and 0.26 ± 0.19 at 14, 30, and 60 dpi, respectively. The mean seizure duration was 15 ± 2 seconds and 24 ± 3 seconds for WT and AQP4 KO mice, respectively. The percentage of mice that developed PTE were 28% and 37% for WT and AQP4 KO mice, respectively. Power spectral density (PSD) analysis revealed alterations in EEG frequency bands between sham and TBI in both genotypes. Additionally, PSD analysis of spontaneous recurrent seizures revealed alterations in delta power between genotypes. Morlet wavelet analysis detected heterogeneity in EEG seizure subtypes and dynamic EEG power patterns after TBI. Compared with AQP4 KO mice, a significant increase in ESD was observed in WT mice at 14 dpi. SIGNIFICANCE Posttraumatic seizures (PTSs) may be modulated by the astrocyte water channel AQP4. Absence of AQP4 increases the number of spontaneous seizures, increases seizure duration, and alters EEG power patterns of PTSs.
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Affiliation(s)
- Jenny I Szu
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Dillon D Patel
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Som Chaturvedi
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Jonathan W Lovelace
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
| | - Devin K Binder
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, Riverside, California, USA
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26
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Binder DK, Boison D, Eid T, Frankel WN, Mingorance A, Smith BN, Dacks PA, Whittemore V, Poduri A. Epilepsy Benchmarks Area II: Prevent Epilepsy and Its Progression. Epilepsy Curr 2020; 20:14S-22S. [PMID: 31937124 PMCID: PMC7031802 DOI: 10.1177/1535759719895274] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [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] [Indexed: 02/06/2023] Open
Abstract
Area II of the 2014 Epilepsy Research Benchmarks aims to establish goals for preventing the development and progression of epilepsy. In this review, we will highlight key advances in Area II since the last summary of research progress and opportunities was published in 2016. We also highlight areas of investigation that began to develop before 2016 and in which additional progress has been made more recently.
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Affiliation(s)
- Devin K Binder
- Division of Biomedical Sciences, School of Medicine, Center for Glial-Neuronal Interactions, University of California, Riverside, CA, USA
| | - Detlev Boison
- Department of Neurosurgery, Robert Wood Johnson and New Jersey Medical Schools, Rutgers University, Piscataway, NJ, USA
| | - Tore Eid
- Department of Laboratory Medicine, Neurosurgery and Molecular Physiology, Yale University, New Haven, CT, USA
| | - Wayne N Frankel
- Department of Genetics & Development, Institute for Genomic Medicine, Columbia University Irving Medical Center, New York, NY, USA
| | | | - Bret N Smith
- Department of Neuroscience, University of Kentucky College of Medicine, Lexington, KY, USA
| | | | - Vicky Whittemore
- Division of Neuroscience, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Annapurna Poduri
- Epilepsy Genetics Program, Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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27
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Szu JI, Chaturvedi S, Patel DD, Binder DK. Aquaporin-4 Dysregulation in a Controlled Cortical Impact Injury Model of Posttraumatic Epilepsy. Neuroscience 2019; 428:140-153. [PMID: 31866558 DOI: 10.1016/j.neuroscience.2019.12.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [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: 10/22/2019] [Revised: 11/25/2019] [Accepted: 12/03/2019] [Indexed: 11/15/2022]
Abstract
Posttraumatic epilepsy (PTE) is a long-term negative consequence of traumatic brain injury (TBI) in which recurrent spontaneous seizures occur after the initial head injury. PTE develops over an undefined period during which circuitry reorganization in the brain causes permanent hyperexcitability. The pathophysiology by which trauma leads to spontaneous seizures is unknown and clinically relevant models of PTE are key to understanding the molecular and cellular mechanisms underlying the development of PTE. In the present study, we used the controlled-cortical impact (CCI) injury model of TBI to induce PTE in mice and to characterize changes in aquaporin-4 (AQP4) expression. A moderate-severe TBI was induced in the right frontal cortex and video-electroencephalographic (vEEG) recordings were performed in the ipsilateral hippocampus to monitor for spontaneous seizures at 14, 30, 60, and 90 days post injury (dpi). The percentage of mice that developed PTE were 13%, 20%, 27%, and 14% at 14, 30, 60, and 90 dpi, respectively. We found a significant increase in AQP4 in the ipsilateral frontal cortex and hippocampus of mice that developed PTE compared to those that did not develop PTE. Interestingly, AQP4 was found to be mislocalized away from the perivascular endfeet and towards the neuropil in mice that developed PTE. Here, we report for the first time, AQP4 dysregulation in a model of PTE which may carry significant implications for epileptogenesis after TBI.
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Affiliation(s)
- Jenny I Szu
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Som Chaturvedi
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Dillon D Patel
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA
| | - Devin K Binder
- Center for Glial-Neuronal Interactions, Division of Biomedical Sciences, School of Medicine, University of California, Riverside, CA, USA.
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28
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Abstract
Repair of the traumatically injured brain has been envisioned for decades, but regenerating new neurons at the site of brain injury has been challenging. We show GABAergic progenitors, derived from the embryonic medial ganglionic eminence, migrate long distances following transplantation into the hippocampus of adult mice with traumatic brain injury, functionally integrate as mature inhibitory interneurons and restore post-traumatic decreases in synaptic inhibition. Grafted animals had improvements in memory precision that were reversed by chemogenetic silencing of the transplanted neurons and a long-lasting reduction in spontaneous seizures. Our results reveal a striking ability of transplanted interneurons for incorporating into injured brain circuits, and this approach is a powerful therapeutic strategy for correcting post-traumatic memory and seizure disorders.
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Affiliation(s)
- Bingyao Zhu
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Jisu Eom
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA
| | - Robert F Hunt
- Department of Anatomy & Neurobiology, University of California, Irvine, CA, 92697, USA. .,Center for the Neurobiology of Learning and Memory, University of California, Irvine, CA, 92697, USA. .,Sue and Bill Gross Stem Cell Research Center, University of California, Irvine, CA, 92697, USA.
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29
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Webster KM, Shultz SR, Ozturk E, Dill LK, Sun M, Casillas-espinosa P, Jones NC, Crack PJ, O'brien TJ, Semple BD. Targeting high-mobility group box protein 1 (HMGB1) in pediatric traumatic brain injury: Chronic neuroinflammatory, behavioral, and epileptogenic consequences. Exp Neurol 2019; 320:112979. [DOI: 10.1016/j.expneurol.2019.112979] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/29/2019] [Accepted: 06/18/2019] [Indexed: 11/18/2022]
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30
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Anwer M, Bolkvadze T, Puhakka N, Ndode-Ekane XE, Pitkänen A. Genotype and Injury Effect on the Expression of a Novel Hypothalamic Protein Sushi Repeat-Containing Protein X-Linked 2 (SRPX2). Neuroscience 2019; 415:184-200. [DOI: 10.1016/j.neuroscience.2019.07.040] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/04/2019] [Accepted: 07/23/2019] [Indexed: 12/17/2022]
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31
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Saletti PG, Ali I, Casillas-Espinosa PM, Semple BD, Lisgaras CP, Moshé SL, Galanopoulou AS. In search of antiepileptogenic treatments for post-traumatic epilepsy. Neurobiol Dis 2019; 123:86-99. [PMID: 29936231 PMCID: PMC6309524 DOI: 10.1016/j.nbd.2018.06.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [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: 05/23/2018] [Accepted: 06/20/2018] [Indexed: 11/28/2022] Open
Abstract
Post-traumatic epilepsy (PTE) is diagnosed in 20% of individuals with acquired epilepsy, and can impact significantly the quality of life due to the seizures and other functional or cognitive and behavioral outcomes of the traumatic brain injury (TBI) and PTE. There is no available antiepileptogenic or disease modifying treatment for PTE. Animal models of TBI and PTE have been developed, offering useful insights on the value of inflammatory, neurodegenerative pathways, hemorrhages and iron accumulation, calcium channels and other target pathways that could be used for treatment development. Most of the existing preclinical studies test efficacy towards pathologies of functional recovery after TBI, while a few studies are emerging testing the effects towards induced or spontaneous seizures. Here we review the existing preclinical trials testing new candidate treatments for TBI sequelae and PTE, and discuss future directions for efforts aiming at developing antiepileptogenic and disease-modifying treatments.
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Affiliation(s)
- Patricia G Saletti
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Idrish Ali
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Pablo M Casillas-Espinosa
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Bridgette D Semple
- Department of Neuroscience, Central Clinical School, Monash University, The Alfred Hospital, Melbourne, Australia; Department of Medicine (Royal Melbourne Hospital), The University of Melbourne, Melbourne, Australia
| | - Christos Panagiotis Lisgaras
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Solomon L Moshé
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA; Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, NY, USA; Department of Pediatrics, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, NY, USA
| | - Aristea S Galanopoulou
- Saul R. Korey Department of Neurology, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Bronx, NY, USA; Dominick P. Purpura Department of Neuroscience, Laboratory of Developmental Epilepsy, Albert Einstein College of Medicine, Einstein/Montefiore Epilepsy Center, Montefiore Medical Center, Bronx, NY, USA.
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32
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Koenig JB, Dulla CG. Dysregulated Glucose Metabolism as a Therapeutic Target to Reduce Post-traumatic Epilepsy. Front Cell Neurosci 2018; 12:350. [PMID: 30459556 PMCID: PMC6232824 DOI: 10.3389/fncel.2018.00350] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [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: 06/19/2018] [Accepted: 09/19/2018] [Indexed: 12/13/2022] Open
Abstract
Traumatic brain injury (TBI) is a significant cause of disability worldwide and can lead to post-traumatic epilepsy. Multiple molecular, cellular, and network pathologies occur following injury which may contribute to epileptogenesis. Efforts to identify mechanisms of disease progression and biomarkers which predict clinical outcomes have focused heavily on metabolic changes. Advances in imaging approaches, combined with well-established biochemical methodologies, have revealed a complex landscape of metabolic changes that occur acutely after TBI and then evolve in the days to weeks after. Based on this rich clinical and preclinical data, combined with the success of metabolic therapies like the ketogenic diet in treating epilepsy, interest has grown in determining whether manipulating metabolic activity following TBI may have therapeutic value to prevent post-traumatic epileptogenesis. Here, we focus on changes in glucose utilization and glycolytic activity in the brain following TBI and during seizures. We review relevant literature and outline potential paths forward to utilize glycolytic inhibitors as a disease-modifying therapy for post-traumatic epilepsy.
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Affiliation(s)
- Jenny B Koenig
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
| | - Chris G Dulla
- Department of Neuroscience, Tufts University School of Medicine, Boston, MA, United States
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33
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Missault S, Anckaerts C, Blockx I, Deleye S, Van Dam D, Barriche N, De Pauw G, Aertgeerts S, Valkenburg F, De Deyn PP, Verhaeghe J, Wyffels L, Van der Linden A, Staelens S, Verhoye M, Dedeurwaerdere S. Neuroimaging of Subacute Brain Inflammation and Microstructural Changes Predicts Long-Term Functional Outcome after Experimental Traumatic Brain Injury. J Neurotrauma 2018; 36:768-788. [PMID: 30032713 DOI: 10.1089/neu.2018.5704] [Citation(s) in RCA: 26] [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] [Indexed: 12/14/2022] Open
Abstract
There is currently a lack of prognostic biomarkers to predict the different sequelae following traumatic brain injury (TBI). The present study investigated the hypothesis that subacute neuroinflammation and microstructural changes correlate with chronic TBI deficits. Rats were subjected to controlled cortical impact (CCI) injury, sham surgery, or skin incision (naïve). CCI-injured (n = 18) and sham-operated rats (n = 6) underwent positron emission tomography (PET) imaging with the translocator protein 18 kDa (TSPO) radioligand [18F]PBR111 and diffusion tensor imaging (DTI) in the subacute phase (≤3 weeks post-injury) to quantify inflammation and microstructural alterations. CCI-injured, sham-operated, and naïve rats (n = 8) underwent behavioral testing in the chronic phase (5.5-10 months post-injury): open field and sucrose preference tests, two one-week video-electroencephalogram (vEEG) monitoring periods, pentylenetetrazole (PTZ) seizure susceptibility tests, and a Morris water maze (MWM) test. In vivo imaging revealed pronounced neuroinflammation, decreased fractional anisotropy, and increased diffusivity in perilesional cortex and ipsilesional hippocampus of CCI-injured rats. Behavioral analysis revealed disinhibition, anhedonia, increased seizure susceptibility, and impaired learning in CCI-injured rats. Subacute TSPO expression and changes in DTI metrics significantly correlated with several chronic deficits (Pearson's |r| = 0.50-0.90). Certain specific PET and DTI parameters had good sensitivity and specificity (area under the receiver operator characteristic [ROC] curve = 0.85-1.00) to distinguish between TBI animals with and without particular behavioral deficits. Depending on the investigated behavioral deficit, PET or DTI data alone, or the combination, could very well predict the variability in functional outcome data (adjusted R2 = 0.54-1.00). Taken together, both TSPO PET and DTI seem promising prognostic biomarkers to predict different chronic TBI sequelae.
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Affiliation(s)
- Stephan Missault
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium .,2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Cynthia Anckaerts
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Ines Blockx
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Steven Deleye
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Debby Van Dam
- 4 Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen (UMCG) , Groningen, The Netherlands
| | - Nora Barriche
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Glenn De Pauw
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Stephanie Aertgeerts
- 1 Experimental Laboratory of Translational Neuroscience and Otolaryngology, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Femke Valkenburg
- 4 Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen (UMCG) , Groningen, The Netherlands
| | - Peter Paul De Deyn
- 4 Laboratory of Neurochemistry and Behavior, Institute Born-Bunge, University of Antwerp, Wilrijk, Belgium; Department of Neurology and Alzheimer Research Center, University of Groningen and University Medical Center Groningen (UMCG) , Groningen, The Netherlands
| | - Jeroen Verhaeghe
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Leonie Wyffels
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium .,5 Department of Nuclear Medicine, University Hospital Antwerp , Edegem, Belgium
| | - Annemie Van der Linden
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Steven Staelens
- 3 Molecular Imaging Center Antwerp, Faculty of Medicine and Health Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Marleen Verhoye
- 2 Bio-Imaging Lab, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
| | - Stefanie Dedeurwaerdere
- 6 Laboratory of Experimental Hematology, Faculty of Medicine and Health Sciences, University of Antwerp , Wilrijk, Belgium
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Frankowski JC, Kim YJ, Hunt RF. Selective vulnerability of hippocampal interneurons to graded traumatic brain injury. Neurobiol Dis 2018; 129:208-216. [PMID: 30031783 DOI: 10.1016/j.nbd.2018.07.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [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: 05/15/2018] [Revised: 06/26/2018] [Accepted: 07/18/2018] [Indexed: 12/21/2022] Open
Abstract
Traumatic brain injury is a major risk factor for many long-term mental health problems. Although underlying mechanisms likely involve compromised inhibition, little is known about how individual subpopulations of interneurons are affected by neurotrauma. Here we report long-term loss of hippocampal interneurons following controlled cortical impact (CCI) injury in young-adult mice, a model of focal cortical contusion injury in humans. Brain injured mice displayed subfield and cell-type specific decreases in interneurons 30 days after impact depths of 0.5 mm and 1.0 mm, and increasing the depth of impact led to greater cell loss. In general, we found a preferential reduction of interneuron cohorts located in principal cell and polymorph layers, while cell types positioned in the molecular layer appeared well preserved. Our results suggest a dramatic shift of interneuron diversity following contusion injury that may contribute to the pathophysiology of traumatic brain injury.
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Affiliation(s)
- Jan C Frankowski
- Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA
| | - Young J Kim
- Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA
| | - Robert F Hunt
- Department of Anatomy & Neurobiology, University of California, Irvine, CA 92697, USA.
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Verley DR, Torolira D, Pulido B, Gutman B, Bragin A, Mayer A, Harris NG. Remote Changes in Cortical Excitability after Experimental Traumatic Brain Injury and Functional Reorganization. J Neurotrauma 2018; 35:2448-2461. [PMID: 29717625 DOI: 10.1089/neu.2017.5536] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Although cognitive and behavioral deficits are well known to occur following traumatic brain injury (TBI), motor deficits that occur even after mild trauma are far less known, yet are equally persistent. This study was aimed at making progress toward determining how the brain reorganizes in response to TBI. We used the adult rat controlled cortical impact injury model to study the ipsilesional forelimb map evoked by electrical stimulation of the affected limb, as well as the contralesional forelimb map evoked by stimulation of the unaffected limb, both before injury and at 1, 2, 3, and 4 weeks after using functional magnetic resonance imaging (fMRI). End-point c-FOS immunohistochemistry data following 1 h of constant stimulation of the unaffected limb were acquired in the same rats to avoid any potential confounds due to altered cerebrovascular coupling. Single and paired-pulse sensory evoked potential (SEP) data were recorded from skull electrodes over the contralesional cortex in a parallel series of rats before injury, at 3 days, and at 1, 2, 3, and 4 weeks after injury in order to determine whether alterations in cortical excitability accompanied reorganization of the cortical map. The results show a transient trans-hemispheric shift in the ipsilesional cortical map as indicated by fMRI, remote contralesional increases in cortical excitability that occur in spatially similar regions to altered fMRI activity and greater c-FOS activation, and reduced or absent ipsilesional cortical activity chronically. The contralesional changes also were indicated by reduced SEP latency within 3 days after injury, but not by blood oxygenation level-dependent fMRI until much later. Detailed interrogation of cortical excitability using paired-pulse electrophysiology showed that the contralesional cortex undergoes both an early and a late post-injury period of hyper-excitability in response to injury, interspersed by a period of relatively normal activity. From these data, we postulate a cross-hemispheric mechanism by which remote cortex excitability inhibits ipsilesional activation by rebalanced cortical excitation-inhibition.
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Affiliation(s)
- Derek R Verley
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
| | - Daniel Torolira
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
| | - Brandon Pulido
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
| | - Boris Gutman
- 2 Department of Neurology, Imaging Genetics Center, Keck/ University of Southern California School of Medicine, Institute for Neuroimaging and Informatics, University of Southern California , California
| | - Anatol Bragin
- 3 Department of Neurology, University of California , Los Angeles, California
| | - Andrew Mayer
- 4 The MIND Research Network and Department of Neurology, University of New Mexico , Albuquerque, New Mexico
| | - Neil G Harris
- 1 UCLA Brain Injury Research Center, Department of Neurosurgery, University of California , Los Angeles, California
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Perucca P, Smith G, Santana-Gomez C, Bragin A, Staba R. Electrophysiological biomarkers of epileptogenicity after traumatic brain injury. Neurobiol Dis 2018; 123:69-74. [PMID: 29883622 DOI: 10.1016/j.nbd.2018.06.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [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: 04/07/2018] [Revised: 05/30/2018] [Accepted: 06/03/2018] [Indexed: 02/08/2023] Open
Abstract
Post-traumatic epilepsy is the architype of acquired epilepsies, wherein a brain insult initiates an epileptogenic process culminating in an unprovoked seizure after weeks, months or years. Identifying biomarkers of such process is a prerequisite for developing and implementing targeted therapies aimed at preventing the development of epilepsy. Currently, there are no validated electrophysiological biomarkers of post-traumatic epileptogenesis. Experimental EEG studies using the lateral fluid percussion injury model have identified three candidate biomarkers of post-traumatic epileptogenesis: pathological high-frequency oscillations (HFOs, 80-300 Hz); repetitive HFOs and spikes (rHFOSs); and reduction in sleep spindle duration and dominant frequency at the transition from stage III to rapid eye movement sleep. EEG studies in humans have yielded conflicting data; recent evidence suggests that epileptiform abnormalities detected acutely after traumatic brain injury carry a significantly increased risk of subsequent epilepsy. Well-designed studies are required to validate these promising findings, and ultimately establish whether there are post-traumatic electrophysiological features which can guide the development of 'antiepileptogenic' therapies.
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Affiliation(s)
- Piero Perucca
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, VIC, Australia; Department of Neurology, The Royal Melbourne Hospital, Melbourne, VIC, Australia; Department of Neurology, Alfred Health, Melbourne, VIC, Australia; Melbourne Medical School, The University of Melbourne, Melbourne, VIC, Australia.
| | - Gregory Smith
- Department of Neurosurgery, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Cesar Santana-Gomez
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Anatol Bragin
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
| | - Richard Staba
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA
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Folweiler KA, Samuel S, Metheny HE, Cohen AS. Diminished Dentate Gyrus Filtering of Cortical Input Leads to Enhanced Area Ca3 Excitability after Mild Traumatic Brain Injury. J Neurotrauma 2018; 35:1304-1317. [PMID: 29338620 PMCID: PMC5962932 DOI: 10.1089/neu.2017.5350] [Citation(s) in RCA: 18] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mild traumatic brain injury (mTBI) disrupts hippocampal function and can lead to long-lasting episodic memory impairments. The encoding of episodic memories relies on spatial information processing within the hippocampus. As the primary entry point for spatial information into the hippocampus, the dentate gyrus is thought to function as a physiological gate, or filter, of afferent excitation before reaching downstream area Cornu Ammonis (CA3). Although injury has previously been shown to alter dentate gyrus network excitability, it is unknown whether mTBI affects dentate gyrus output to area CA3. In this study, we assessed hippocampal function, specifically the interaction between the dentate gyrus and CA3, using behavioral and electrophysiological techniques in ex vivo brain slices 1 week following mild lateral fluid percussion injury (LFPI). Behaviorally, LFPI mice were found to be impaired in an object-place recognition task, indicating that spatial information processing in the hippocampus is disrupted. Extracellular recordings and voltage-sensitive dye imaging demonstrated that perforant path activation leads to the aberrant spread of excitation from the dentate gyrus into area CA3 along the mossy fiber pathway. These results suggest that after mTBI, the dentate gyrus has a diminished capacity to regulate cortical input into the hippocampus, leading to increased CA3 network excitability. The loss of the dentate filtering efficacy reveals a potential mechanism by which hippocampal-dependent spatial information processing is disrupted, and may contribute to memory dysfunction after mTBI.
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Affiliation(s)
- Kaitlin A. Folweiler
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Anesthesiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Sandy Samuel
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Anesthesiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Hannah E. Metheny
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Anesthesiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Akiva S. Cohen
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
- Department of Anesthesiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
- Neuroscience Graduate Group, University of Pennsylvania, Philadelphia, Pennsylvania
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Klein P, Dingledine R, Aronica E, Bernard C, Blümcke I, Boison D, Brodie MJ, Brooks-Kayal AR, Engel J, Forcelli PA, Hirsch LJ, Kaminski RM, Klitgaard H, Kobow K, Lowenstein DH, Pearl PL, Pitkänen A, Puhakka N, Rogawski MA, Schmidt D, Sillanpää M, Sloviter RS, Steinhäuser C, Vezzani A, Walker MC, Löscher W. Commonalities in epileptogenic processes from different acute brain insults: Do they translate? Epilepsia 2018; 59:37-66. [PMID: 29247482 PMCID: PMC5993212 DOI: 10.1111/epi.13965] [Citation(s) in RCA: 179] [Impact Index Per Article: 29.8] [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] [Accepted: 11/01/2017] [Indexed: 12/12/2022]
Abstract
The most common forms of acquired epilepsies arise following acute brain insults such as traumatic brain injury, stroke, or central nervous system infections. Treatment is effective for only 60%-70% of patients and remains symptomatic despite decades of effort to develop epilepsy prevention therapies. Recent preclinical efforts are focused on likely primary drivers of epileptogenesis, namely inflammation, neuron loss, plasticity, and circuit reorganization. This review suggests a path to identify neuronal and molecular targets for clinical testing of specific hypotheses about epileptogenesis and its prevention or modification. Acquired human epilepsies with different etiologies share some features with animal models. We identify these commonalities and discuss their relevance to the development of successful epilepsy prevention or disease modification strategies. Risk factors for developing epilepsy that appear common to multiple acute injury etiologies include intracranial bleeding, disruption of the blood-brain barrier, more severe injury, and early seizures within 1 week of injury. In diverse human epilepsies and animal models, seizures appear to propagate within a limbic or thalamocortical/corticocortical network. Common histopathologic features of epilepsy of diverse and mostly focal origin are microglial activation and astrogliosis, heterotopic neurons in the white matter, loss of neurons, and the presence of inflammatory cellular infiltrates. Astrocytes exhibit smaller K+ conductances and lose gap junction coupling in many animal models as well as in sclerotic hippocampi from temporal lobe epilepsy patients. There is increasing evidence that epilepsy can be prevented or aborted in preclinical animal models of acquired epilepsy by interfering with processes that appear common to multiple acute injury etiologies, for example, in post-status epilepticus models of focal epilepsy by transient treatment with a trkB/PLCγ1 inhibitor, isoflurane, or HMGB1 antibodies and by topical administration of adenosine, in the cortical fluid percussion injury model by focal cooling, and in the albumin posttraumatic epilepsy model by losartan. Preclinical studies further highlight the roles of mTOR1 pathways, JAK-STAT3, IL-1R/TLR4 signaling, and other inflammatory pathways in the genesis or modulation of epilepsy after brain injury. The wealth of commonalities, diversity of molecular targets identified preclinically, and likely multidimensional nature of epileptogenesis argue for a combinatorial strategy in prevention therapy. Going forward, the identification of impending epilepsy biomarkers to allow better patient selection, together with better alignment with multisite preclinical trials in animal models, should guide the clinical testing of new hypotheses for epileptogenesis and its prevention.
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Affiliation(s)
- Pavel Klein
- Mid-Atlantic Epilepsy and Sleep Center, Bethesda, MD, USA
| | | | - Eleonora Aronica
- Department of (Neuro) Pathology, Academic Medical Center and Swammerdam Institute for Life Sciences, Center for Neuroscience, University of Amsterdam, Amsterdam, The Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - Christophe Bernard
- Aix Marseille Univ, Inserm, INS, Instit Neurosci Syst, Marseille, 13005, France
| | - Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | - Detlev Boison
- Robert Stone Dow Neurobiology Laboratories, Legacy Research Institute, Portland, OR, USA
| | - Martin J Brodie
- Epilepsy Unit, West Glasgow Ambulatory Care Hospital-Yorkhill, Glasgow, UK
| | - Amy R Brooks-Kayal
- Division of Neurology, Departments of Pediatrics and Neurology, University of Colorado School of Medicine, Aurora, CO, USA
- Children's Hospital Colorado, Aurora, CO, USA
- Neuroscience Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Jerome Engel
- Departments of Neurology, Neurobiology, and Psychiatry and Biobehavioral Sciences, David Geffen School of Medicine, Brain Research Institute, University of California, Los Angeles, CA, USA
| | | | | | | | | | - Katja Kobow
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | | | - Phillip L Pearl
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Asla Pitkänen
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Noora Puhakka
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, Kuopio, Finland
| | - Michael A Rogawski
- Department of Neurology, University of California, Davis, Sacramento, CA, USA
| | | | - Matti Sillanpää
- Departments of Child Neurology and General Practice, University of Turku and Turku University Hospital, Turku, Finland
| | - Robert S Sloviter
- Department of Neurobiology, Morehouse School of Medicine, Atlanta, GA, USA
| | - Christian Steinhäuser
- Institute of Cellular Neurosciences, Medical Faculty, University of Bonn, Bonn, Germany
| | - Annamaria Vezzani
- Department of Neuroscience, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, Institute for Pharmacological Research, Milan,, Italy
| | - Matthew C Walker
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London, UK
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, Hannover, Germany
- Center for Systems Neuroscience, Hannover, Germany
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Butler CR, Boychuk JA, Smith BN. Brain Injury-Induced Synaptic Reorganization in Hilar Inhibitory Neurons Is Differentially Suppressed by Rapamycin. eNeuro 2017; 4:ENEURO. [PMID: 29085896 DOI: 10.1523/ENEURO.0134-17.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 09/07/2017] [Accepted: 09/20/2017] [Indexed: 12/18/2022] Open
Abstract
Following traumatic brain injury (TBI), treatment with rapamycin suppresses mammalian (mechanistic) target of rapamycin (mTOR) activity and specific components of hippocampal synaptic reorganization associated with altered cortical excitability and seizure susceptibility. Reemergence of seizures after cessation of rapamycin treatment suggests, however, an incomplete suppression of epileptogenesis. Hilar inhibitory interneurons regulate dentate granule cell (DGC) activity, and de novo synaptic input from both DGCs and CA3 pyramidal cells after TBI increases their excitability but effects of rapamycin treatment on the injury-induced plasticity of interneurons is only partially described. Using transgenic mice in which enhanced green fluorescent protein (eGFP) is expressed in the somatostatinergic subset of hilar inhibitory interneurons, we tested the effect of daily systemic rapamycin treatment (3 mg/kg) on the excitability of hilar inhibitory interneurons after controlled cortical impact (CCI)-induced focal brain injury. Rapamycin treatment reduced, but did not normalize, the injury-induced increase in excitability of surviving eGFP+ hilar interneurons. The injury-induced increase in response to selective glutamate photostimulation of DGCs was reduced to normal levels after mTOR inhibition, but the postinjury increase in synaptic excitation arising from CA3 pyramidal cell activity was unaffected by rapamycin treatment. The incomplete suppression of synaptic reorganization in inhibitory circuits after brain injury could contribute to hippocampal hyperexcitability and the eventual reemergence of the epileptogenic process upon cessation of mTOR inhibition. Further, the cell-selective effect of mTOR inhibition on synaptic reorganization after CCI suggests possible mechanisms by which rapamycin treatment modifies epileptogenesis in some models but not others.
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Semple BD, O'Brien TJ, Gimlin K, Wright DK, Kim SE, Casillas-Espinosa PM, Webster KM, Petrou S, Noble-Haeusslein LJ. Interleukin-1 Receptor in Seizure Susceptibility after Traumatic Injury to the Pediatric Brain. J Neurosci 2017; 37:7864-77. [PMID: 28724747 DOI: 10.1523/JNEUROSCI.0982-17.2017] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/29/2017] [Accepted: 07/07/2017] [Indexed: 12/19/2022] Open
Abstract
Epilepsy after pediatric traumatic brain injury (TBI) is associated with poor quality of life. This study aimed to characterize post-traumatic epilepsy in a mouse model of pediatric brain injury, and to evaluate the role of interleukin-1 (IL-1) signaling as a target for pharmacological intervention. Male mice received a controlled cortical impact or sham surgery at postnatal day 21, approximating a toddler-aged child. Mice were treated acutely with an IL-1 receptor antagonist (IL-1Ra; 100 mg/kg, s.c.) or vehicle. Spontaneous and evoked seizures were evaluated from video-EEG recordings. Behavioral assays tested for functional outcomes, postmortem analyses assessed neuropathology, and brain atrophy was detected by ex vivo magnetic resonance imaging. At 2 weeks and 3 months post-injury, TBI mice showed an elevated seizure response to the convulsant pentylenetetrazol compared with sham mice, associated with abnormal hippocampal mossy fiber sprouting. A robust increase in IL-1β and IL-1 receptor were detected after TBI. IL-1Ra treatment reduced seizure susceptibility 2 weeks after TBI compared with vehicle, and a reduction in hippocampal astrogliosis. In a chronic study, IL-1Ra-TBI mice showed improved spatial memory at 4 months post-injury. At 5 months, most TBI mice exhibited spontaneous seizures during a 7 d video-EEG recording period. At 6 months, IL-1Ra-TBI mice had fewer evoked seizures compared with vehicle controls, coinciding with greater preservation of cortical tissue. Findings demonstrate this model's utility to delineate mechanisms underlying epileptogenesis after pediatric brain injury, and provide evidence of IL-1 signaling as a mediator of post-traumatic astrogliosis and seizure susceptibility.SIGNIFICANCE STATEMENT Epilepsy is a common cause of morbidity after traumatic brain injury in early childhood. However, a limited understanding of how epilepsy develops, particularly in the immature brain, likely contributes to the lack of efficacious treatments. In this preclinical study, we first demonstrate that a mouse model of traumatic injury to the pediatric brain reproduces many neuropathological and seizure-like hallmarks characteristic of epilepsy. Second, we demonstrate that targeting the acute inflammatory response reduces cognitive impairments, the degree of neuropathology, and seizure susceptibility, after pediatric brain injury in mice. These findings provide evidence that inflammatory cytokine signaling is a key process underlying epilepsy development after an acquired brain insult, which represents a feasible therapeutic target to improve quality of life for survivors.
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Pöttker B, Stöber F, Hummel R, Angenstein F, Radyushkin K, Goldschmidt J, Schäfer MKE. Traumatic brain injury causes long-term behavioral changes related to region-specific increases of cerebral blood flow. Brain Struct Funct 2017; 222:4005-4021. [DOI: 10.1007/s00429-017-1452-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 05/27/2017] [Indexed: 12/19/2022]
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Shi XY, Hu LY, Liu MJ, Zou LP. Hypercapnia-induced brain acidosis: Effects and putative mechanisms on acute kainate induced seizures. Life Sci 2017; 176:82-87. [DOI: 10.1016/j.lfs.2017.03.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Revised: 03/21/2017] [Accepted: 03/22/2017] [Indexed: 01/16/2023]
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White ER, Pinar C, Bostrom CA, Meconi A, Christie BR. Mild Traumatic Brain Injury Produces Long-Lasting Deficits in Synaptic Plasticity in the Female Juvenile Hippocampus. J Neurotrauma 2017; 34:1111-1123. [DOI: 10.1089/neu.2016.4638] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Emily R. White
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Cristina Pinar
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Crystal A. Bostrom
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Alicia Meconi
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
| | - Brian R. Christie
- Division of Medical Sciences and Neuroscience Graduate Program, University of Victoria, Victoria, British Columbia, Canada
- Centre for Brain Health and Program in Neuroscience, University of British Columbia, Vancouver, British Columbia, Canada
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, British Columbia, Canada
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Abstract
Traumatic brain injury (TBI) greatly increases the risk of medically intractable epilepsy. Several models of TBI have been developed to investigate the relationship between TBI and posttraumatic epileptogenesis. Because the incident that precipitates development of epilepsy is known, studying mechanisms of epileptogenesis, identifying biomarkers to predict PTE, and developing treatments to prevent epilepsy after TBI are attainable research goals.
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Butler CR, Boychuk JA, Smith BN. Differential effects of rapamycin treatment on tonic and phasic GABAergic inhibition in dentate granule cells after focal brain injury in mice. Exp Neurol 2016; 280:30-40. [PMID: 27018320 DOI: 10.1016/j.expneurol.2016.03.022] [Citation(s) in RCA: 18] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2016] [Revised: 03/07/2016] [Accepted: 03/20/2016] [Indexed: 10/22/2022]
Abstract
The cascade of events leading to post-traumatic epilepsy (PTE) after traumatic brain injury (TBI) remains unclear. Altered inhibition in the hippocampal formation and dentate gyrus is a hallmark of several neurological disorders, including TBI and PTE. Inhibitory synaptic signaling in the hippocampus is predominately driven by γ-aminobutyric acid (GABA) neurotransmission, and is prominently mediated by postsynaptic type A GABA receptors (GABAAR's). Subsets of these receptors involved in tonic inhibition of neuronal membranes serve a fundamental role in maintenance of inhibitory state, and GABAAR-mediated tonic inhibition is altered functionally in animal models of both TBI and epilepsy. In this study, we assessed the effect of mTOR inhibition on hippocampal hilar inhibitory interneuron loss and synaptic and tonic GABAergic inhibition of dentate gyrus granule cells (DGCs) after controlled cortical impact (CCI) to determine if mTOR activation after TBI modulates GABAAR function. Hilar inhibitory interneuron density was significantly reduced 72h after CCI injury in the dorsal two-thirds of the hemisphere ipsilateral to injury compared with the contralateral hemisphere and sham controls. Rapamycin treatment did not alter this reduction in cell density. Synaptic and tonic current measurements made in DGCs at both 1-2 and 8-13weeks post-injury indicated reduced synaptic inhibition and THIP-induced tonic current density in DGCs ipsilateral to CCI injury at both time points post-injury, with no change in resting tonic GABAAR-mediated currents. Rapamycin treatment did not alter the reduced synaptic inhibition observed in ipsilateral DGCs 1-2weeks post-CCI injury, but further reduced synaptic inhibition of ipsilateral DGCs at 8-13weeks post-injury. The reduction in THIP-induced tonic current after injury, however, was prevented by rapamycin treatment at both time points. Rapamycin treatment thus differentially modifies CCI-induced changes in synaptic and tonic GABAAR-mediated currents in DGCs.
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Affiliation(s)
- Corwin R Butler
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, United States
| | - Jeffery A Boychuk
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, United States; Epilepsy Center, University of Kentucky, Lexington, KY 40536, United States; Center for Advanced Translational Stroke Science, University of Kentucky, Lexington, KY 40536, United States
| | - Bret N Smith
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY 40536, United States; Epilepsy Center, University of Kentucky, Lexington, KY 40536, United States; Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky, Lexington, KY 40536, United States.
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Boychuk JA, Butler CR, Halmos KC, Smith BN. Enduring changes in tonic GABAA receptor signaling in dentate granule cells after controlled cortical impact brain injury in mice. Exp Neurol 2016; 277:178-89. [DOI: 10.1016/j.expneurol.2016.01.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/16/2015] [Accepted: 01/05/2016] [Indexed: 11/23/2022]
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Abstract
Stem-cell therapy has extraordinary potential to address critical, unmet needs in the treatment of human disease. One particularly promising approach for the treatment of epilepsy is to increase inhibition in areas of the epileptic brain by grafting new inhibitory cortical interneurons. When grafted from embryos, young γ-aminobutyric acid (GABA)ergic precursors disperse, functionally mature into host brain circuits as local-circuit interneurons, and can stop seizures in both genetic and acquired forms of the disease. These features make interneuron cell transplantation an attractive new approach for the treatment of intractable epilepsies, as well as other brain disorders that involve increased risk for epilepsy as a comorbidity. Here, we review recent efforts to isolate and transplant cortical interneuron precursors derived from embryonic mouse and human cell sources. We also discuss some of the important challenges that must be addressed before stem-cell-based treatment for human epilepsy is realized.
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Affiliation(s)
- Robert F Hunt
- Department of Anatomy & Neurobiology, University of California Irvine, Irvine, California 92697
| | - Scott C Baraban
- Department of Anatomy & Neurobiology, University of California Irvine, Irvine, California 92697
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Lucke-Wold BP, Nguyen L, Turner RC, Logsdon AF, Chen YW, Smith KE, Huber JD, Matsumoto R, Rosen CL, Tucker ES, Richter E. Traumatic brain injury and epilepsy: Underlying mechanisms leading to seizure. Seizure 2015; 33:13-23. [PMID: 26519659 DOI: 10.1016/j.seizure.2015.10.002] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [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: 06/10/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 02/08/2023] Open
Abstract
Post-traumatic epilepsy continues to be a major concern for those experiencing traumatic brain injury. Post-traumatic epilepsy accounts for 10-20% of epilepsy cases in the general population. While seizure prophylaxis can prevent early onset seizures, no available treatments effectively prevent late-onset seizure. Little is known about the progression of neural injury over time and how this injury progression contributes to late onset seizure development. In this comprehensive review, we discuss the epidemiology and risk factors for post-traumatic epilepsy and the current pharmacologic agents used for treatment. We highlight limitations with the current approach and offer suggestions for remedying the knowledge gap. Critical to this pursuit is the design of pre-clinical models to investigate important mechanistic factors responsible for post-traumatic epilepsy development. We discuss what the current models have provided in terms of understanding acute injury and what is needed to advance understanding regarding late onset seizure. New model designs will be used to investigate novel pathways linking acute injury to chronic changes within the brain. Important components of this transition are likely mediated by toll-like receptors, neuroinflammation, and tauopathy. In the final section, we highlight current experimental therapies that may prove promising in preventing and treating post-traumatic epilepsy. By increasing understanding about post-traumatic epilepsy and injury expansion over time, it will be possible to design better treatments with specific molecular targets to prevent late-onset seizure occurrence following traumatic brain injury.
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Affiliation(s)
- Brandon P Lucke-Wold
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV 26506, USA; The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Linda Nguyen
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV 26506, USA
| | - Ryan C Turner
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV 26506, USA; The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Aric F Logsdon
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA; Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV 26506, USA
| | - Yi-Wen Chen
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Kelly E Smith
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV 26506, USA
| | - Jason D Huber
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA; Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV 26506, USA
| | - Rae Matsumoto
- Department of Basic Pharmaceutical Sciences, West Virginia University School of Pharmacy, Morgantown, WV 26506, USA; College of Pharmacy, Touro University California, 1310 Club Drive, Vallejo, CA 94592, USA
| | - Charles L Rosen
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV 26506, USA; The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Eric S Tucker
- The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA
| | - Erich Richter
- Department of Neurosurgery, West Virginia University School of Medicine, Morgantown, WV 26506, USA; The Center for Neuroscience, West Virginia University School of Medicine, Morgantown, WV 26506, USA.
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Butler CR, Boychuk JA, Smith BN. Effects of Rapamycin Treatment on Neurogenesis and Synaptic Reorganization in the Dentate Gyrus after Controlled Cortical Impact Injury in Mice. Front Syst Neurosci 2015; 9:163. [PMID: 26640431 PMCID: PMC4661228 DOI: 10.3389/fnsys.2015.00163] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [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: 09/04/2015] [Accepted: 11/10/2015] [Indexed: 11/13/2022] Open
Abstract
Post-traumatic epilepsy (PTE) is one consequence of traumatic brain injury (TBI). A prominent cell signaling pathway activated in animal models of both TBI and epilepsy is the mammalian target of rapamycin (mTOR). Inhibition of mTOR with rapamycin has shown promise as a potential modulator of epileptogenesis in several animal models of epilepsy, but cellular mechanisms linking mTOR expression and epileptogenesis are unclear. In this study, the role of mTOR in modifying functional hippocampal circuit reorganization after focal TBI induced by controlled cortical impact (CCI) was investigated. Rapamycin (3 or 10 mg/kg), an inhibitor of mTOR signaling, was administered by intraperitoneal injection beginning on the day of injury and continued daily until tissue collection. Relative to controls, rapamycin treatment reduced dentate granule cell area in the hemisphere ipsilateral to the injury two weeks post-injury. Brain injury resulted in a significant increase in doublecortin immunolabeling in the dentate gyrus ipsilateral to the injury, indicating increased neurogenesis shortly after TBI. Rapamycin treatment prevented the increase in doublecortin labeling, with no overall effect on Fluoro-Jade B staining in the ipsilateral hemisphere, suggesting that rapamycin treatment reduced posttraumatic neurogenesis but did not prevent cell loss after injury. At later times post-injury (8–13 weeks), evidence of mossy fiber sprouting and increased recurrent excitation of dentate granule cells was detected, which were attenuated by rapamycin treatment. Rapamycin treatment also diminished seizure prevalence relative to vehicle-treated controls after TBI. Collectively, these results support a role for adult neurogenesis in PTE development and suggest that suppression of epileptogenesis by mTOR inhibition includes effects on post-injury neurogenesis.
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Affiliation(s)
- Corwin R Butler
- Department of Physiology, College of Medicine, University of Kentucky Lexington, KY, USA
| | - Jeffery A Boychuk
- Department of Physiology, College of Medicine, University of Kentucky Lexington, KY, USA ; Epilepsy Center, University of Kentucky Lexington, KY, USA ; Center for Advanced Translational Stroke Science, University of Kentucky Lexington, KY, USA
| | - Bret N Smith
- Department of Physiology, College of Medicine, University of Kentucky Lexington, KY, USA ; Epilepsy Center, University of Kentucky Lexington, KY, USA ; Spinal Cord and Brain Injury Research Center (SCoBIRC), University of Kentucky Lexington, KY, USA
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Abstract
Epileptogenesis is a chronic process that can be triggered by genetic or acquired factors, and that can continue long after epilepsy diagnosis. In 2015, epileptogenesis is not a treatment indication, and there are no therapies available in clinic to treat individuals at risk of epileptogenesis. However, thanks to active research, a large number of animal models have become available for search of molecular mechanisms of epileptogenesis. The first glimpses of treatment targets and biomarkers that could be developed to become useful in clinic are in sight. However, the heterogeneity of the epilepsy condition, and the dynamics of molecular changes over the course of epileptogenesis remain as challenges to overcome.
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Affiliation(s)
- Asla Pitkänen
- Department of Neurobiology, A. I. Virtanen Institute for Molecular Sciences, University of Eastern Finland, FI-70211 Kuopio, Finland Department of Neurology, Kuopio University Hospital, FI-70211 Kuopio, Finland
| | - Katarzyna Lukasiuk
- The Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
| | - F Edward Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah 84108
| | - Kevin J Staley
- Department of Neurology, Massachusetts General Hospital, Boston, Massachusetts 02114
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