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Bascuñana P, Javela J, Delgado M, Fernández de la Rosa R, Shiha AA, García-García L, Pozo MÁ. [18F]FDG PET Neuroimaging Predicts Pentylenetetrazole (PTZ) Kindling Outcome in Rats. Mol Imaging Biol 2016; 18:733-40. [DOI: 10.1007/s11307-016-0950-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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52
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Brennan GP, Dey D, Chen Y, Patterson KP, Magnetta EJ, Hall AM, Dube CM, Mei YT, Baram TZ. Dual and Opposing Roles of MicroRNA-124 in Epilepsy Are Mediated through Inflammatory and NRSF-Dependent Gene Networks. Cell Rep 2016; 14:2402-12. [PMID: 26947066 DOI: 10.1016/j.celrep.2016.02.042] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 12/22/2015] [Accepted: 02/04/2016] [Indexed: 12/25/2022] Open
Abstract
Insult-provoked transformation of neuronal networks into epileptic ones involves multiple mechanisms. Intervention studies have identified both dysregulated inflammatory pathways and NRSF-mediated repression of crucial neuronal genes as contributors to epileptogenesis. However, it remains unclear how epilepsy-provoking insults (e.g., prolonged seizures) induce both inflammation and NRSF and whether common mechanisms exist. We examined miR-124 as a candidate dual regulator of NRSF and inflammatory pathways. Status epilepticus (SE) led to reduced miR-124 expression via SIRT1--and, in turn, miR-124 repression--via C/EBPα upregulated NRSF. We tested whether augmenting miR-124 after SE would abort epileptogenesis by preventing inflammation and NRSF upregulation. SE-sustaining animals developed epilepsy, but supplementing miR-124 did not modify epileptogenesis. Examining this result further, we found that synthetic miR-124 not only effectively blocked NRSF upregulation and rescued NRSF target genes, but also augmented microglia activation and inflammatory cytokines. Thus, miR-124 attenuates epileptogenesis via NRSF while promoting epilepsy via inflammation.
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Affiliation(s)
- Gary P Brennan
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA; Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, CA 92697, USA
| | - Deblina Dey
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA
| | - Yuncai Chen
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA
| | - Katelin P Patterson
- Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, CA 92697, USA
| | - Eric J Magnetta
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA
| | - Alicia M Hall
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA; Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, CA 92697, USA
| | - Celine M Dube
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA; Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, CA 92697, USA
| | - Yu-Tang Mei
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA
| | - Tallie Z Baram
- Department of Pediatrics, University of California, Irvine, Irvine, CA 92697, USA; Department of Anatomy & Neurobiology, University of California, Irvine, Irvine, CA 92697, USA; Department of Neurology, University of California, Irvine, Irvine, CA 92697, USA.
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Zhan Q, Buchanan GF, Motelow JE, Andrews J, Vitkovskiy P, Chen WC, Serout F, Gummadavelli A, Kundishora A, Furman M, Li W, Bo X, Richerson GB, Blumenfeld H. Impaired Serotonergic Brainstem Function during and after Seizures. J Neurosci 2016; 36:2711-22. [PMID: 26937010 PMCID: PMC4879214 DOI: 10.1523/jneurosci.4331-15.2016] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Revised: 01/11/2016] [Accepted: 01/23/2016] [Indexed: 12/30/2022] Open
Abstract
Impaired breathing, cardiac function, and arousal during and after seizures are important causes of morbidity and mortality. Previous work suggests that these changes are associated with depressed brainstem function in the ictal and post-ictal periods. Lower brainstem serotonergic systems are postulated to play an important role in cardiorespiratory changes during and after seizures, whereas upper brainstem serotonergic and other systems regulate arousal. However, direct demonstration of seizure-associated neuronal activity changes in brainstem serotonergic regions has been lacking. Here, we performed multiunit and single-unit recordings from medullary raphe and midbrain dorsal raphe nuclei in an established rat seizure model while measuring changes in breathing rate and depth as well as heart rate. Serotonergic neurons were identified by immunohistochemistry. Respiratory rate, tidal volume, and minute ventilation were all significantly decreased during and after seizures in this model. We found that population firing of neurons in the medullary and midbrain raphe on multiunit recordings was significantly decreased during the ictal and post-ictal periods. Single-unit recordings from identified serotonergic neurons in the medullary raphe revealed highly consistently decreased firing during and after seizures. In contrast, firing of midbrain raphe serotonergic neurons was more variable, with a mixture of increases and decreases. The markedly suppressed firing of medullary serotonergic neurons supports their possible role in simultaneously impaired cardiorespiratory function in seizures. Decreased arousal likely arises from depressed population activity of several neuronal pools in the upper brainstem and forebrain. These findings have important implications for preventing morbidity and mortality in people living with epilepsy. SIGNIFICANCE STATEMENT Seizures often cause impaired breathing, cardiac dysfunction, and loss of consciousness. The brainstem and, specifically, brainstem serotonin neurons are thought to play an important role in controlling breathing, cardiac function, and arousal. We used an established rat seizure model to study the overall neuronal activity in the brainstem as well as firing of specific serotonin neurons while measuring cardiorespiratory function. Our results demonstrated overall decreases in brainstem neuronal activity and marked downregulation of lower brainstem serotonin neuronal firing in association with decreased breathing and heart rate during and after seizures. These findings point the way toward new treatments to augment brainstem function and serotonin, aiming to prevent seizure complications and reduce morbidity and mortality in people living with epilepsy.
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Affiliation(s)
- Qiong Zhan
- Departments of Neurology, Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China, Department of Neurology, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | | | | | | | | | | | | | | | | | | | - Wei Li
- Departments of Neurology, Department of Neurosurgery, Jinling Hospital, School of Medicine Nanjing University, Nanjing Jiangsu 210002, China, and
| | - Xiao Bo
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan 410008, China
| | - George B Richerson
- Departments of Neurology and Molecular Physiology and Biophysics, and Veterans Affairs Medical Center, Iowa City, Iowa 52246
| | - Hal Blumenfeld
- Departments of Neurology, Neuroscience, and Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06520,
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54
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Structural alterations in the rat brain and behavioral impairment after status epilepticus: An MRI study. Neuroscience 2016; 315:79-90. [DOI: 10.1016/j.neuroscience.2015.11.061] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2015] [Revised: 11/07/2015] [Accepted: 11/26/2015] [Indexed: 12/26/2022]
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55
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Vezzani A, Fujinami RS, White HS, Preux PM, Blümcke I, Sander JW, Löscher W. Infections, inflammation and epilepsy. Acta Neuropathol 2016; 131:211-234. [PMID: 26423537 DOI: 10.1007/s00401-015-1481-5] [Citation(s) in RCA: 293] [Impact Index Per Article: 36.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 09/18/2015] [Accepted: 09/20/2015] [Indexed: 12/15/2022]
Abstract
Epilepsy is the tendency to have unprovoked epileptic seizures. Anything causing structural or functional derangement of brain physiology may lead to seizures, and different conditions may express themselves solely by recurrent seizures and thus be labelled "epilepsy." Worldwide, epilepsy is the most common serious neurological condition. The range of risk factors for the development of epilepsy varies with age and geographic location. Congenital, developmental and genetic conditions are mostly associated with the development of epilepsy in childhood, adolescence and early adulthood. Head trauma, infections of the central nervous system (CNS) and tumours may occur at any age and may lead to the development of epilepsy. Infections of the CNS are a major risk factor for epilepsy. The reported risk of unprovoked seizures in population-based cohorts of survivors of CNS infections from developed countries is between 6.8 and 8.3 %, and is much higher in resource-poor countries. In this review, the various viral, bacterial, fungal and parasitic infectious diseases of the CNS which result in seizures and epilepsy are discussed. The pathogenesis of epilepsy due to brain infections, as well as the role of experimental models to study mechanisms of epileptogenesis induced by infectious agents, is reviewed. The sterile (non-infectious) inflammatory response that occurs following brain insults is also discussed, as well as its overlap with inflammation due to infections, and the potential role in epileptogenesis. Furthermore, autoimmune encephalitis as a cause of seizures is reviewed. Potential strategies to prevent epilepsy resulting from brain infections and non-infectious inflammation are also considered.
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Affiliation(s)
- Annamaria Vezzani
- Department of Neuroscience, IRCCS-"Mario Negri" Institute for Pharmacological Research, Milan, Italy
| | - Robert S Fujinami
- Department of Pathology, University of Utah, Salt Lake City, UT, USA
| | - H Steve White
- Department of Pharmacology, University of Utah, Salt Lake City, UT, USA
| | - Pierre-Marie Preux
- INSERM UMR1094, Tropical Neuroepidemiology, Limoges, France
- Institute of Neuroepidemiology and Tropical Neurology, School of Medicine, University of Limoges, Limoges, France
- Center of Epidemiology, Biostatistics, and Research Methodology, CHU Limoges, Limoges, France
| | - Ingmar Blümcke
- Department of Neuropathology, University Hospital Erlangen, Erlangen, Germany
| | - Josemir W Sander
- NIHR University College London Hospitals Biomedical Research Centre, UCL Institute of Neurology, London, WC1N £BG, UK
- Stichting Epilepsie Instellingen Nederland (SEIN), Heemstede, The Netherlands
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559, Hannover, Germany.
- Center for Systems Neuroscience, Hannover, Germany.
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56
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Bröer S, Löscher W. Novel combinations of phenotypic biomarkers predict development of epilepsy in the lithium-pilocarpine model of temporal lobe epilepsy in rats. Epilepsy Behav 2015; 53:98-107. [PMID: 26539702 DOI: 10.1016/j.yebeh.2015.09.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 09/22/2015] [Indexed: 10/22/2022]
Abstract
The discovery and validation of biomarkers in neurological and neurodegenerative diseases is an important challenge for early diagnosis of disease and for the development of therapeutics. Epilepsy is often a consequence of brain insults such as traumatic brain injury or stroke, but as yet no biomarker exists to predict the development of epilepsy in patients at risk. Given the complexity of epilepsy, it is unlikely that a single biomarker is sufficient for this purpose, but a combinatorial approach may be needed to overcome the challenge of individual variability and disease heterogeneity. The goal of the present prospective study in the lithium-pilocarpine model of epilepsy in rats was to determine the discriminative utility of combinations of phenotypic biomarkers by examining their ability to predict epilepsy. For this purpose, we used a recent model refinement that allows comparing rats that will or will not develop spontaneous recurrent seizures (SRS) after pilocarpine-induced status epilepticus (SE). Potential biomarkers included in our study were seizure threshold and seizure severity in response to timed i.v. infusion of pentylenetetrazole (PTZ) and behavioral alterations determined by a battery of tests during the three weeks following SE. Three months after SE, video/EEG monitoring was used to determine which rats had developed SRS. To determine whether a biomarker or combination of biomarkers performed better than chance at predicting epilepsy after SE, derived data underwent receiver operating characteristic (ROC) curve analyses. When comparing rats with and without SRS and sham controls, the best intergroup discrimination was obtained by combining all measurements, resulting in a ROC area under curve (AUC) of 0.9592 (P<0.01), indicating an almost perfect discrimination or accuracy to predict development of SRS. These data indicate that a combinatorial biomarker approach may overcome the challenge of individual variability in the prediction of epilepsy.
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Affiliation(s)
- Sonja Bröer
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine, 30559 Hannover, Germany; Center for Systems Neuroscience, 30559 Hannover, Germany.
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57
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Rapid, Coordinate Inflammatory Responses after Experimental Febrile Status Epilepticus: Implications for Epileptogenesis. eNeuro 2015; 2:eN-NWR-0034-15. [PMID: 26730400 PMCID: PMC4699830 DOI: 10.1523/eneuro.0034-15.2015] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 09/25/2015] [Accepted: 09/28/2015] [Indexed: 11/29/2022] Open
Abstract
Epilepsy is a common neurological disorder with many causes. For temporal lobe epilepsy, antecedent insults are typically found. These risk factors include trauma or history of long fever-associated seizures (febrile status epilepticus) in childhood. Whereas the mechanisms by which such insults promote temporal lobe epilepsy are unknown, an extensive body of work has implicated inflammation and inflammatory mediators in both human and animal models of the disorder. However, direct evidence for an epileptogenic role for inflammation is lacking. Here we capitalized on a model where only a subgroup of insult-experiencing rodents develops epilepsy. We reasoned that if inflammation was important for generating epilepsy, then early inflammation should be more prominent in individuals destined to become epileptic compared with those that will not become epileptic. In addition, the molecular and temporal profile of inflammatory mediators would provide insights into which inflammatory pathways might be involved in the disease process. We examined inflammatory profiles in hippocampus and amygdala of individual rats and correlated them with a concurrent noninvasive, amygdalar magnetic resonance imaging epilepsy-predictive marker. We found significant individual variability in the expression of several important inflammatory mediators, but not in others. Of interest, a higher expression of a subset of hippocampal and amygdalar inflammatory markers within the first few hours following an insult correlated with the epilepsy-predictive signal. These findings suggest that some components of the inflammatory gene network might contribute to the process by which insults promote the development of temporal lobe epilepsy.
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58
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Wu Y, Pearce PS, Rapuano A, Hitchens TK, de Lanerolle NC, Pan JW. Metabolic changes in early poststatus epilepticus measured by MR spectroscopy in rats. J Cereb Blood Flow Metab 2015; 35:1862-70. [PMID: 26104287 PMCID: PMC4635243 DOI: 10.1038/jcbfm.2015.145] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 05/17/2015] [Accepted: 05/20/2015] [Indexed: 11/09/2022]
Abstract
There is little experimental in vivo data on how differences in seizure duration in experimental status epilepticus influence metabolic injury. This is of interest given that in humans, status duration is a factor that influences the probability of subsequent development of epilepsy. This question is studied using 7-T magnetic resonance (MR) spectroscopy, T2 relaxometry in the incremented kainate rodent model of temporal lobe epilepsy, using two durations of status epilepticus, 1.5 and 3 hours. Histologic evaluation was performed in a subset of animals. Three days after status, single-voxel (8 mm(3)) point resolved spectroscopy (PRESS) MR spectroscopic measurements were acquired at 7 T to assess the cerebral metabolites measured as a ratio to total creatine (tCr). The status injury resulted in decreased N-acetylaspartate NAA/tCr, increased myo-inositol/tCr and glutamine/tCr, increased T2, and significant declines in NeuN-stained neuronal counts in both status groups. Regressions were identified in the status groups that provide evidence for neuronal injury and astrocytic reaction after status in both the short and long status duration groups. The long status group displays changes in glutathione/tCr that are not identified in the short status group, this difference possibly representing a maturation of injury and antioxidant response that occurs in synchrony with glutamatergic injury and glial activation.
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Affiliation(s)
- Yijen Wu
- Department of Developmental Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Patrice S Pearce
- Departments of Neurology and Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Amedeo Rapuano
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, USA
| | - T Kevin Hitchens
- Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon University, Pittsburgh, Pennsylvania, USA
| | - Nihal C de Lanerolle
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jullie W Pan
- Departments of Neurology and Radiology, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
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59
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Imaging microstructural damage and plasticity in the hippocampus during epileptogenesis. Neuroscience 2015; 309:162-72. [DOI: 10.1016/j.neuroscience.2015.04.054] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Revised: 03/28/2015] [Accepted: 04/21/2015] [Indexed: 12/19/2022]
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60
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Suchomelova L, Lopez-Meraz ML, Niquet J, Kubova H, Wasterlain CG. Hyperthermia aggravates status epilepticus-induced epileptogenesis and neuronal loss in immature rats. Neuroscience 2015; 305:209-24. [PMID: 26259902 DOI: 10.1016/j.neuroscience.2015.08.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Revised: 07/20/2015] [Accepted: 08/03/2015] [Indexed: 01/16/2023]
Abstract
This study tightly controlled seizure duration and severity during status epilepticus (SE) in postnatal day 10 (P10) rats, in order to isolate hyperthermia as the main variable and to study its consequences. Body temperature was maintained at 39 ± 1 °C in hyperthermic SE rats (HT+SE) or at 35 ± 1 °C in normothermic SE animals (NT+SE) during 30 min of SE, which was induced by lithium-pilocarpine (3 mEq/kg, 60 mg/kg) and terminated by diazepam and cooling to NT. All video/EEG measures of SE severity were similar between HT+SE and NT+SE pups. At 24h, neuronal injury was present in the amygdala in the HT+SE group only, and was far more severe in the hippocampus in HT+SE than NT+SE pups. Separate groups of animals were monitored four months later for spontaneous recurrent seizures (SRS). Only HT+SE animals developed convulsive SRS. Both HT+SE and NT+SE animals developed electrographic SRS (83% vs. 55%), but SRS frequency and severity were higher in hyperthermic animals (12.5 ± 3.5 vs. 4.2 ± 2.0 SRS/day). The density of hilar neurons was lower, thickness of the amygdala and perirhinal cortex was reduced, and lateral ventricles were enlarged in HT+SE over NT+SE littermates and HT/NT controls. In this model, hyperthermia greatly increased the epileptogenicity of SE and its neuropathological sequelae.
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Affiliation(s)
- L Suchomelova
- Veterans Administration Greater Los Angeles Healthcare System, Epilepsy Research (151), 11 301 Wilshire Boulevard, Building 114, Room 139, Los Angeles, CA 90073, USA.
| | - M L Lopez-Meraz
- Centro de Investigaciones Cerebrales, Universidad Veracruzana, Veracruz 91190, Mexico
| | - J Niquet
- Veterans Administration Greater Los Angeles Healthcare System, Epilepsy Research (151), 11 301 Wilshire Boulevard, Building 114, Room 139, Los Angeles, CA 90073, USA
| | - H Kubova
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Videnska 1083, Prague 14220, Czech Republic
| | - C G Wasterlain
- Department of Neurology, David Geffen School of Medicine at UCLA, VA Medical Center (127), 11 301 Wilshire Boulevard, Los Angeles, CA 90073, USA
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61
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Moreira-Filho CA, Bando SY, Bertonha FB, Iamashita P, Silva FN, Costa LDF, Silva AV, Castro LHM, Wen HT. Community structure analysis of transcriptional networks reveals distinct molecular pathways for early- and late-onset temporal lobe epilepsy with childhood febrile seizures. PLoS One 2015; 10:e0128174. [PMID: 26011637 PMCID: PMC4444281 DOI: 10.1371/journal.pone.0128174] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 04/24/2015] [Indexed: 12/21/2022] Open
Abstract
Age at epilepsy onset has a broad impact on brain plasticity and epilepsy pathomechanisms. Prolonged febrile seizures in early childhood (FS) constitute an initial precipitating insult (IPI) commonly associated with mesial temporal lobe epilepsy (MTLE). FS-MTLE patients may have early disease onset, i.e. just after the IPI, in early childhood, or late-onset, ranging from mid-adolescence to early adult life. The mechanisms governing early (E) or late (L) disease onset are largely unknown. In order to unveil the molecular pathways underlying E and L subtypes of FS-MTLE we investigated global gene expression in hippocampal CA3 explants of FS-MTLE patients submitted to hippocampectomy. Gene coexpression networks (GCNs) were obtained for the E and L patient groups. A network-based approach for GCN analysis was employed allowing: i) the visualization and analysis of differentially expressed (DE) and complete (CO) - all valid GO annotated transcripts - GCNs for the E and L groups; ii) the study of interactions between all the system's constituents based on community detection and coarse-grained community structure methods. We found that the E-DE communities with strongest connection weights harbor highly connected genes mainly related to neural excitability and febrile seizures, whereas in L-DE communities these genes are not only involved in network excitability but also playing roles in other epilepsy-related processes. Inversely, in E-CO the strongly connected communities are related to compensatory pathways (seizure inhibition, neuronal survival and responses to stress conditions) while in L-CO these communities harbor several genes related to pro-epileptic effects, seizure-related mechanisms and vulnerability to epilepsy. These results fit the concept, based on fMRI and behavioral studies, that early onset epilepsies, although impacting more severely the hippocampus, are associated to compensatory mechanisms, while in late MTLE development the brain is less able to generate adaptive mechanisms, what has implications for epilepsy management and drug discovery.
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Affiliation(s)
| | - Silvia Yumi Bando
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil
| | - Fernanda Bernardi Bertonha
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil
| | - Priscila Iamashita
- Department of Pediatrics, Faculdade de Medicina da Universidade de São Paulo (FMUSP), São Paulo, SP, Brazil
| | | | | | | | - Luiz Henrique Martins Castro
- Department of Neurology, FMUSP, São Paulo, SP, Brazil
- Clinical Neurology Division, Hospital das Clínicas, FMUSP, São Paulo, SP, Brazil
| | - Hung-Tzu Wen
- Epilepsy Surgery Group, Hospital das Clínicas, FMUSP, São Paulo, SP, Brazil
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62
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Barry JM, Choy M, Dube C, Robbins A, Obenaus A, Lenck-Santini PP, Scott RC, Baram TZ, Holmes GL. T2 relaxation time post febrile status epilepticus predicts cognitive outcome. Exp Neurol 2015; 269:242-52. [PMID: 25939697 DOI: 10.1016/j.expneurol.2015.04.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/31/2015] [Accepted: 04/23/2015] [Indexed: 11/30/2022]
Abstract
Evidence from animal models and patient data indicates that febrile status epilepticus (FSE) in early development can result in permanently diminished cognitive abilities. To understand the variability in cognitive outcome following FSE, we used MRI to measure dynamic brain metabolic responses to the induction of FSE in juvenile rats. We then compared these measurements to the ability to learn an active avoidance spatial task weeks later. T2 relaxation times were significantly lower in FSE rats that were task learners in comparison to FSE non-learners. While T2 time in whole brain held the greatest predictive power, T2 in hippocampus and basolateral amygdala were also excellent predictors. These signal differences in response to FSE indicate that rats that fail to meet metabolic and oxygen demand are more likely to develop spatial cognition deficits. Place cells from FSE non-learners had significantly larger firing fields and higher in-field firing rate than FSE learners and control animals and imply increased excitability in the pyramidal cells of FSE non-learners. These findings suggest a mechanistic cause for the spatial memory deficits in active avoidance and are relevant to other acute neurological insults in early development where cognitive outcome is a concern.
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Affiliation(s)
- Jeremy M Barry
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT, United States; Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States.
| | - ManKin Choy
- Department of Neurology, University of California-Irvine, Irvine, CA, United States
| | - Celine Dube
- Department of Neurology, University of California-Irvine, Irvine, CA, United States
| | - Ashlee Robbins
- Department of Neurology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Andre Obenaus
- Department of Radiation Medicine, Loma Linda University, Riverside, CA, United States
| | - Pierre Pascal Lenck-Santini
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT, United States
| | - Rod C Scott
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT, United States; Department of Neurology, University College London, Institute of Child Health, United Kingdom
| | - Tallie Z Baram
- Department of Neurology, University of California-Irvine, Irvine, CA, United States
| | - Gregory L Holmes
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, VT, United States
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63
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Vezzani A. Anti-inflammatory drugs in epilepsy: does it impact epileptogenesis? Expert Opin Drug Saf 2015; 14:583-92. [DOI: 10.1517/14740338.2015.1010508] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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64
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Abstract
Epilepsy is more prevalent in populations with high measures of stress, but the neurobiological mechanisms are unclear. Stress is a common precipitant of seizures in individuals with epilepsy, and may provoke seizures by several mechanisms including changes in neurotransmitter and hormone levels within the brain. Importantly, stress during sensitive periods early in life contributes to ‘brain programming’, influencing neuronal function and brain networks. However, it is unclear if early-life stress influences limbic excitability and promotes epilepsy. Here we used an established, naturalistic model of chronic early-life stress (CES), and employed chronic cortical and limbic video-EEGs combined with molecular and cellular techniques to probe the contributions of stress to age-specific epilepsies and network hyperexcitability and identify the underlying mechanisms. In control male rats, EEGs obtained throughout development were normal and no seizures were observed. EEGs demonstrated epileptic spikes and spike series in the majority of rats experiencing CES, and 57% of CES rats developed seizures: Behavioral events resembling the human age-specific epilepsy infantile spasms occurred in 11/23 (48%), accompanied by EEG spikes and/or electrodecrements, and two additional rats (9%) developed limbic seizures that involved the amygdala. Probing for stress-dependent, endogenous convulsant molecules within amygdala, we examined the expression of the pro-convulsant neuropeptide corticotropin-releasing hormone (CRH), and found a significant increase of amygdalar--but not cortical--CRH expression in adolescent CES rats. In conclusion, CES of limited duration has long-lasting effects on brain excitability and may promote age-specific seizures and epilepsy. Whereas the mechanisms involved require further study, these findings provide important insights into environmental contributions to early-life seizures.
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