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Vermoyal JC, Hardy D, Goirand-Lopez L, Vinck A, Silvagnoli L, Fortoul A, Francis F, Cappello S, Bureau I, Represa A, Cardoso C, Watrin F, Marissal T, Manent JB. Grey matter heterotopia subtypes show specific morpho-electric signatures and network dynamics. Brain 2024; 147:996-1010. [PMID: 37724593 DOI: 10.1093/brain/awad318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Revised: 08/04/2023] [Accepted: 09/07/2023] [Indexed: 09/21/2023] Open
Abstract
Grey matter heterotopia (GMH) are neurodevelopmental disorders associated with abnormal cortical function and epilepsy. Subcortical band heterotopia (SBH) and periventricular nodular heterotopia (PVNH) are two well-recognized GMH subtypes in which neurons are misplaced, either forming nodules lining the ventricles in PVNH, or forming bands in the white matter in SBH. Although both PVNH and SBH are commonly associated with epilepsy, it is unclear whether these two GMH subtypes differ in terms of pathological consequences or, on the contrary, share common altered mechanisms. Here, we studied two robust preclinical models of SBH and PVNH, and performed a systematic comparative assessment of the physiological and morphological diversity of heterotopia neurons, as well as the dynamics of epileptiform activity and input connectivity. We uncovered a complex set of altered properties, including both common and distinct physiological and morphological features across heterotopia subtypes, and associated with specific dynamics of epileptiform activity. Taken together, these results suggest that pro-epileptic circuits in GMH are, at least in part, composed of neurons with distinct, subtype-specific, physiological and morphological properties depending on the heterotopia subtype. Our work supports the notion that GMH represent a complex set of disorders, associating both shared and diverging pathological consequences, and contributing to forming epileptogenic networks with specific properties. A deeper understanding of these properties may help to refine current GMH classification schemes by identifying morpho-electric signatures of GMH subtypes, to potentially inform new treatment strategies.
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Affiliation(s)
- Jean-Christophe Vermoyal
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Delphine Hardy
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Lucas Goirand-Lopez
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Antonin Vinck
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Lucas Silvagnoli
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Aurélien Fortoul
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Fiona Francis
- INSERM, Sorbonne University, Institut du Fer à Moulin, Paris 75005, France
| | - Silvia Cappello
- Department of Physiological Genomics, Biomedical Center, LMU Munich, Planegg-Martinsried 82152, Germany
| | - Ingrid Bureau
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Alfonso Represa
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Carlos Cardoso
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Françoise Watrin
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Thomas Marissal
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
| | - Jean-Bernard Manent
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille 13009, France
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Hardy D, Buhler E, Suchkov D, Vinck A, Fortoul A, Watrin F, Represa A, Minlebaev M, Manent JB. Early suppression of excitability in subcortical band heterotopia modifies epileptogenesis in rats. Neurobiol Dis 2023; 177:106002. [PMID: 36649744 DOI: 10.1016/j.nbd.2023.106002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 01/04/2023] [Accepted: 01/13/2023] [Indexed: 01/15/2023] Open
Abstract
Malformations of cortical development represent a major cause of epilepsy in childhood. However, the pathological substrate and dynamic changes leading to the development and progression of epilepsy remain unclear. Here, we characterized an etiology-relevant rat model of subcortical band heterotopia (SBH), a diffuse type of cortical malformation associated with drug-resistant seizures in humans. We used longitudinal electrographic recordings to monitor the age-dependent evolution of epileptiform discharges during the course of epileptogenesis in this model. We found both quantitative and qualitative age-related changes in seizures properties and patterns, accompanying a gradual progression towards a fully developed seizure pattern seen in adulthood. We also dissected the relative contribution of the band heterotopia and the overlying cortex to the development and age-dependent progression of epilepsy using timed and spatially targeted manipulation of neuronal excitability. We found that an early suppression of neuronal excitability in SBH slows down epileptogenesis in juvenile rats, whereas epileptogenesis is paradoxically exacerbated when excitability is suppressed in the overlying cortex. However, in rats with active epilepsy, similar manipulations of excitability have no effect on chronic spontaneous seizures. Together, our data support the notion that complex developmental alterations occurring in both the SBH and the overlying cortex concur to creating pathogenic circuits prone to generate seizures. Our study also suggests that early and targeted interventions could potentially influence the course of these altered developmental trajectories, and favorably modify epileptogenesis in malformations of cortical development.
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Affiliation(s)
- Delphine Hardy
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Emmanuelle Buhler
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Dmitrii Suchkov
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Antonin Vinck
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Aurélien Fortoul
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Françoise Watrin
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Alfonso Represa
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Marat Minlebaev
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France
| | - Jean-Bernard Manent
- INMED, INSERM, Aix-Marseille University, Turing Centre for Living Systems, Marseille, France.
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Damianidou E, Mouratidou L, Kyrousi C. Research models of neurodevelopmental disorders: The right model in the right place. Front Neurosci 2022; 16:1031075. [PMID: 36340790 PMCID: PMC9630472 DOI: 10.3389/fnins.2022.1031075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 10/07/2022] [Indexed: 11/25/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) are a heterogeneous group of impairments that affect the development of the central nervous system leading to abnormal brain function. NDDs affect a great percentage of the population worldwide, imposing a high societal and economic burden and thus, interest in this field has widely grown in recent years. Nevertheless, the complexity of human brain development and function as well as the limitations regarding human tissue usage make their modeling challenging. Animal models play a central role in the investigation of the implicated molecular and cellular mechanisms, however many of them display key differences regarding human phenotype and in many cases, they partially or completely fail to recapitulate them. Although in vitro two-dimensional (2D) human-specific models have been highly used to address some of these limitations, they lack crucial features such as complexity and heterogeneity. In this review, we will discuss the advantages, limitations and future applications of in vivo and in vitro models that are used today to model NDDs. Additionally, we will describe the recent development of 3-dimensional brain (3D) organoids which offer a promising approach as human-specific in vitro models to decipher these complex disorders.
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Affiliation(s)
- Eleni Damianidou
- University Mental Health, Neurosciences and Precision Medicine Research Institute “Costas Stefanis”, Athens, Greece
| | - Lidia Mouratidou
- University Mental Health, Neurosciences and Precision Medicine Research Institute “Costas Stefanis”, Athens, Greece
- First Department of Psychiatry, Medical School, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
| | - Christina Kyrousi
- University Mental Health, Neurosciences and Precision Medicine Research Institute “Costas Stefanis”, Athens, Greece
- First Department of Psychiatry, Medical School, Eginition Hospital, National and Kapodistrian University of Athens, Athens, Greece
- *Correspondence: Christina Kyrousi,
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Florian IA, Beni L, Moisoiu V, Timis TL, Florian IS, Balașa A, Berindan-Neagoe I. 'De Novo' Brain AVMs-Hypotheses for Development and a Systematic Review of Reported Cases. ACTA ACUST UNITED AC 2021; 57:medicina57030201. [PMID: 33652628 PMCID: PMC7996785 DOI: 10.3390/medicina57030201] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Revised: 02/15/2021] [Accepted: 02/22/2021] [Indexed: 12/11/2022]
Abstract
Background and Objectives: Brain arteriovenous malformations AVMs have been consistently regarded as congenital malformations of the cerebral vasculature. However, recent case reports describing "de novo AVMs" have sparked a growing debate on the nature of these lesions. Materials and Methods: We have performed a systematic review of the literature concerning de novo AVMs utilizing the PubMed and Google Academic databases. Termes used in the search were "AVM," "arteriovenous," "de novo," and "acquired," in all possible combinations. Results: 53 articles including a total of 58 patients harboring allegedly acquired AVMs were identified by researching the literature. Of these, 32 were male (55.17%), and 25 were female (43.10%). Mean age at de novo AVM diagnosis was 27.833 years (standard deviation (SD) of 21.215 years and a 95% confidence interval (CI) of 22.3 to 33.3). Most de novo AVMs were managed via microsurgical resection (20 out of 58, 34.48%), followed by radiosurgery and conservative treatment for 11 patients (18.97%) each, endovascular embolization combined with resection for five patients (8.62%), and embolization alone for three (5.17%), the remaining eight cases (13.79%) having an unspecified therapy. Conclusions: Increasing evidence suggests that some of the AVMs discovered develop some time after birth. We are still a long way from finally elucidating their true nature, though there is reason to believe that they can also appear after birth. Thus, we reason that the de novo AVMs are the result of a 'second hit' of a variable type, such as a previous intracranial hemorrhage or vascular pathology. The congenital or acquired characteristic of AVMs may have a tremendous impact on prognosis, risk of hemorrhage, and short and long-term management.
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Affiliation(s)
- Ioan Alexandru Florian
- Clinic of Neurosurgery, Cluj County Emergency Clinical Hospital, 400012 Cluj-Napoca, Romania; (L.B.); (V.M.); (I.S.F.)
- Department of Neurosurgery, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
- Correspondence:
| | - Lehel Beni
- Clinic of Neurosurgery, Cluj County Emergency Clinical Hospital, 400012 Cluj-Napoca, Romania; (L.B.); (V.M.); (I.S.F.)
| | - Vlad Moisoiu
- Clinic of Neurosurgery, Cluj County Emergency Clinical Hospital, 400012 Cluj-Napoca, Romania; (L.B.); (V.M.); (I.S.F.)
| | - Teodora Larisa Timis
- Department of Physiology, Iuliu Hatieganu University of Medicine and Pharmacy, 400006 Cluj-Napoca, Romania;
| | - Ioan Stefan Florian
- Clinic of Neurosurgery, Cluj County Emergency Clinical Hospital, 400012 Cluj-Napoca, Romania; (L.B.); (V.M.); (I.S.F.)
- Department of Neurosurgery, Iuliu Hatieganu University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania
| | - Adrian Balașa
- Clinic of Neurosurgery, Tîrgu Mureș County Clinical Emergency Hospital, 540136 Tîrgu Mureș, Romania;
- Department of Neurosurgery, Tîrgu Mureș University of Medicine, Pharmacy, Science and Technology, 540139 Tîrgu Mureș, Romania
| | - Ioana Berindan-Neagoe
- Research Center for Functional Genomics, Biomedicine, and Translational Medicine, Institute of Doctoral Studies, “Iuliu Hatieganu” University of Medicine and Pharmacy, 400012 Cluj-Napoca, Romania;
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Klingler E, Francis F, Jabaudon D, Cappello S. Mapping the molecular and cellular complexity of cortical malformations. Science 2021; 371:371/6527/eaba4517. [PMID: 33479124 DOI: 10.1126/science.aba4517] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The cerebral cortex is an intricate structure that controls human features such as language and cognition. Cortical functions rely on specialized neurons that emerge during development from complex molecular and cellular interactions. Neurodevelopmental disorders occur when one or several of these steps is incorrectly executed. Although a number of causal genes and disease phenotypes have been identified, the sequence of events linking molecular disruption to clinical expression mostly remains obscure. Here, focusing on human malformations of cortical development, we illustrate how complex interactions at the genetic, cellular, and circuit levels together contribute to diversity and variability in disease phenotypes. Using specific examples and an online resource, we propose that a multilevel assessment of disease processes is key to identifying points of vulnerability and developing new therapeutic strategies.
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Affiliation(s)
- Esther Klingler
- Department of Basic Neurosciences, University of Geneva, CH-1202 Geneva, Switzerland
| | - Fiona Francis
- INSERM U 1270, F-75005 Paris, France.,Sorbonne University, UMR-S 1270, F-75005 Paris, France.,Institut du Fer à Moulin, F-75005 Paris, France
| | - Denis Jabaudon
- Department of Basic Neurosciences, University of Geneva, CH-1202 Geneva, Switzerland. .,Clinic of Neurology, Geneva University Hospital, 1211 Geneva, Switzerland
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Grosenbaugh DK, Joshi S, Fitzgerald MP, Lee KS, Wagley PK, Koeppel AF, Turner SD, McConnell MJ, Goodkin HP. A deletion in Eml1 leads to bilateral subcortical heterotopia in the tish rat. Neurobiol Dis 2020; 140:104836. [PMID: 32179177 PMCID: PMC7814471 DOI: 10.1016/j.nbd.2020.104836] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 03/11/2020] [Accepted: 03/12/2020] [Indexed: 12/13/2022] Open
Abstract
Children with malformations of cortical development (MCD) are at risk for epilepsy, developmental delays, behavioral disorders, and intellectual disabilities. For a subset of these children, antiseizure medications or epilepsy surgery may result in seizure freedom. However, there are limited options for treating or curing the other conditions, and epilepsy surgery is not an option in all cases of pharmacoresistant epilepsy. Understanding the genetic and neurobiological mechanisms underlying MCD is a necessary step in elucidating novel therapeutic targets. The tish (telencephalic internal structural heterotopia) rat is a unique model of MCD with spontaneous seizures, but the underlying genetic mutation(s) have remained unknown. DNA and RNA-sequencing revealed that a deletion encompassing a previously unannotated first exon markedly diminished Eml1 transcript and protein abundance in the tish brain. Developmental electrographic characterization of the tish rat revealed early-onset of spontaneous spike-wave discharge (SWD) bursts beginning at postnatal day (P) 17. A dihybrid cross demonstrated that the mutant Eml1 allele segregates with the observed dysplastic cortex and the early-onset SWD bursts in monogenic autosomal recessive frequencies. Our data link the development of the bilateral, heterotopic dysplastic cortex of the tish rat to a deletion in Eml1.
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Affiliation(s)
- Denise K Grosenbaugh
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Suchitra Joshi
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Mark P Fitzgerald
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Kevin S Lee
- Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States; Department of Neurosurgery, University of Virginia School of Medicine, Charlottesville, VA, United States; Center for Brain Immunology and Glia, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Pravin K Wagley
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Alexander F Koeppel
- Center for Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Stephen D Turner
- Center for Public Health Sciences, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Michael J McConnell
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, United States; Department of Neuroscience, University of Virginia School of Medicine, Charlottesville, VA, United States; Center for Brain Immunology and Glia, University of Virginia School of Medicine, Charlottesville, VA, United States; Center for Public Health Genomics, University of Virginia School of Medicine, Charlottesville, VA, United States.
| | - Howard P Goodkin
- Department of Neurology, University of Virginia School of Medicine, Charlottesville, VA, United States; Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, United States.
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7
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Moustaki K, Buhler E, Martinez R, Watrin F, Represa A, Manent JB. Size of Subcortical Band Heterotopia Influences the Susceptibility to Hyperthermia-Induced Seizures in a Rat Model. Front Cell Neurosci 2019; 13:473. [PMID: 31680876 PMCID: PMC6813413 DOI: 10.3389/fncel.2019.00473] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 10/04/2019] [Indexed: 11/13/2022] Open
Abstract
Studies conducted in human and rodent models have suggested that preexisting neurodevelopmental defects could predispose immature brains to febrile seizures (FS). However, the impact of the anatomical extent of preexisting cortical malformations on FS susceptibility was never assessed. Here, we induced hyperthermic seizures (HS) in rats with bilateral subcortical band heterotopia (SBH) and found variable degrees of HS susceptibility depending on inter-individual anatomical differences in size and extent of SBH. This indicates that an association exists between the overall extent or location of a cortical malformation, and the predisposition to FS. This also suggests that various predisposing factors and underlying causes may contribute to the etiology of complex FS.
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Affiliation(s)
- Kalliopi Moustaki
- Institut de Neurobiologie de la Méditerranée INMED, INSERM UMR 1249, Aix-Marseille University, Marseille, France
| | - Emmanuelle Buhler
- Institut de Neurobiologie de la Méditerranée INMED, INSERM UMR 1249, Aix-Marseille University, Marseille, France
| | - Robert Martinez
- Institut de Neurobiologie de la Méditerranée INMED, INSERM UMR 1249, Aix-Marseille University, Marseille, France
| | - Françoise Watrin
- Institut de Neurobiologie de la Méditerranée INMED, INSERM UMR 1249, Aix-Marseille University, Marseille, France
| | - Alfonso Represa
- Institut de Neurobiologie de la Méditerranée INMED, INSERM UMR 1249, Aix-Marseille University, Marseille, France
| | - Jean-Bernard Manent
- Institut de Neurobiologie de la Méditerranée INMED, INSERM UMR 1249, Aix-Marseille University, Marseille, France
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Sapir T, Barakat TS, Paredes MF, Lerman-Sagie T, Aronica E, Klonowski W, Nguyen L, Ben Zeev B, Bahi-Buisson N, Leventer R, Rachmian N, Reiner O. Building Bridges Between the Clinic and the Laboratory: A Meeting Review - Brain Malformations: A Roadmap for Future Research. Front Cell Neurosci 2019; 13:434. [PMID: 31611776 PMCID: PMC6776596 DOI: 10.3389/fncel.2019.00434] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2019] [Accepted: 09/09/2019] [Indexed: 01/08/2023] Open
Abstract
In the middle of March 2019, a group of scientists and clinicians (as well as those who wear both hats) gathered in the green campus of the Weizmann Institute of Science to share recent scientific findings, to establish collaborations, and to discuss future directions for better diagnosis, etiology modeling and treatment of brain malformations. One hundred fifty scientists from twenty-two countries took part in this meeting. Thirty-eight talks were presented and as many as twenty-five posters were displayed. This review is aimed at presenting some of the highlights that the audience was exposed to during the three-day meeting.
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Affiliation(s)
- Tamar Sapir
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Mercedes F. Paredes
- Department of Neurology and Neuroscience Graduate Division, University of California, San Francisco, San Francisco, CA, United States
| | - Tally Lerman-Sagie
- Pediatric Neurology Unit, Fetal Neurology Clinic, Wolfson Medical Center, Holon and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Eleonora Aronica
- Department of (Neuro-)Pathology, Amsterdam Neuroscience, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Stichting Epilepsie Instellingen Nederland (SEIN), Zwolle, Netherlands
| | - Wlodzimierz Klonowski
- Nalecz Institute of Biocybernetics and Biomedical Engineering, Polish Academy of Sciences, Warsaw, Poland
| | - Laurent Nguyen
- GIGA-Stem Cells, Interdisciplinary Cluster for Applied Genoproteomics (GIGA-R), C.H.U. Sart Tilman, University of Liège, Liège, Belgium
| | - Bruria Ben Zeev
- Sackler School of Medicine and Pediatric Neurology Unit, Edmond and Lilly Safra Pediatric Hospital, Tel Aviv University, Tel Aviv, Israel
| | - Nadia Bahi-Buisson
- INSERM UMR 1163, Imagine Institute, Paris Descartes University, Paris, France
- Necker Enfants Malades Hospital, Pediatrric Neurology APHP, Paris, France
| | - Richard Leventer
- Department of Neurology, Royal Children’s Hospital, Murdoch Children’s Research Institute, University of Melbourne, Parkville, VIC, Australia
- Department of Pediatrics, University of Melbourne, Parkville, VIC, Australia
| | - Noa Rachmian
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
| | - Orly Reiner
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel
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Sahu S, Buhler E, Vermoyal JC, Watrin F, Represa A, Manent JB. Spontaneous epileptiform activity in a rat model of bilateral subcortical band heterotopia. Epilepsia 2018; 60:337-348. [PMID: 30597542 PMCID: PMC7027481 DOI: 10.1111/epi.14633] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2018] [Revised: 11/20/2018] [Accepted: 12/07/2018] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Malformations of cortical development are common causes of intellectual disability and epilepsy, yet there is a crucial lack of relevant preclinical models associating seizures and cortical malformations. Here, we describe a novel rat model with bilateral subcortical band heterotopia (SBH) and examine whether this model develops spontaneous epileptic seizures. METHODS To generate bilateral SBH in rats, we combined RNAi-mediated knockdown of Dcx and in utero electroporation with a tripolar electrode configuration enabling simultaneous transfection of the two brain hemispheres. To determine whether bilateral SBH leads to epileptiform activity, rats of various ages were implanted for telemetric electrocorticographic recordings and histopathological examination was carried out at the end of the recording sessions. RESULTS By 2 months, rats with bilateral SBH showed nonconvulsive spontaneous seizures consisting of spike-and-wave discharges (SWDs) with dominant frequencies in the alpha and theta bands and secondarily in higher-frequency bands. SWDs occurred during both the dark and the light period, but were more frequent during quiet awake state than during sleep. Also, SWDs were more frequent and lasted longer at older ages. No sex differences were found. Although frequencies and durations of SWDs were found to be uncorrelated with the size of SBH, SWDs were initiated in some occasions from brain hemispheres comprising a larger SBH. Lastly, SWDs exhibited absence-like pharmacological properties, being temporarily alleviated by ethosuximide administration. SIGNIFICANCE This novel model of bilateral SBH with spontaneous epilepsy may potentially provide valuable new insights into causality between cortical malformations and seizures, and help translational research aiming at designing novel treatment strategies for epilepsy.
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Affiliation(s)
- Surajit Sahu
- Neurobiology Institute of the Mediterranean (INMED), Aix-Marseille University, French National Institute of Health and Medical Research (INSERM) UMR1249, Marseille, France
| | - Emmanuelle Buhler
- Neurobiology Institute of the Mediterranean (INMED), Aix-Marseille University, French National Institute of Health and Medical Research (INSERM) UMR1249, Marseille, France
| | - Jean-Christophe Vermoyal
- Neurobiology Institute of the Mediterranean (INMED), Aix-Marseille University, French National Institute of Health and Medical Research (INSERM) UMR1249, Marseille, France
| | - Françoise Watrin
- Neurobiology Institute of the Mediterranean (INMED), Aix-Marseille University, French National Institute of Health and Medical Research (INSERM) UMR1249, Marseille, France
| | - Alfonso Represa
- Neurobiology Institute of the Mediterranean (INMED), Aix-Marseille University, French National Institute of Health and Medical Research (INSERM) UMR1249, Marseille, France
| | - Jean-Bernard Manent
- Neurobiology Institute of the Mediterranean (INMED), Aix-Marseille University, French National Institute of Health and Medical Research (INSERM) UMR1249, Marseille, France
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