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Scott RC, Moshé SL, Holmes GL. Do vaccines cause epilepsy? Review of cases in the National Vaccine Injury Compensation Program. Epilepsia 2024; 65:293-321. [PMID: 37914395 DOI: 10.1111/epi.17794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 11/03/2023]
Abstract
OBJECTIVE The National Childhood Vaccine Injury Act of 1986 created the National Vaccine Injury Compensation Program (VICP), a no-fault alternative to the traditional tort system. Since 1988, the total compensation paid exceeds $5 billion. Although epilepsy is one of the leading reasons for filing a claim, there has been no review of the process and validity of the legal outcomes given current medical information. The objectives were to review the evolution of the VICP program in regard to vaccine-related epilepsy and assess the rationale behind decisions made by the court. METHODS Publicly available cases involving epilepsy claims in the VICP were searched through Westlaw and the US Court of Federal Claims websites. All published reports were reviewed for petitioner's theories supporting vaccine-induced epilepsy, respondent's counterarguments, the final decision regarding compensation, and the rationale underlying these decisions. The primary goal was to determine which factors went into decisions regarding whether vaccines caused epilepsy. RESULTS Since the first epilepsy case in 1989, there have been many changes in the program, including the removal of residual seizure disorder as a vaccine-related injury, publication of the Althen prongs, release of the acellular form of pertussis, and recognition that in genetic conditions the underlying genetic abnormality rather than the immunization causes epilepsy. We identified 532 unique cases with epilepsy: 105 with infantile spasms and 427 with epilepsy without infantile spasms. The petitioners' experts often espoused outdated, erroneous causation theories that lacked an acceptable medical or scientific foundation and were frequently criticized by the court. SIGNIFICANCE Despite the lack of epidemiological or mechanistic evidence indicating that childhood vaccines covered by the VICP result in or aggravate epilepsy, these cases continue to be adjudicated. After 35 years of intense litigation, it is time to reconsider whether epilepsy should continue to be a compensable vaccine-induced injury.
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Affiliation(s)
- Rodney C Scott
- Nemours Children's Hospital-Delaware, Wilmington, Delaware, USA
| | - Solomon L Moshé
- Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, USA
| | - Gregory L Holmes
- Larner College of Medicine, University of Vermont, Burlington, Vermont, USA
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Freiman S, Hauser WA, Rider F, Gulyaeva N, Guekht A. Post-stroke epilepsy: From clinical predictors to possible mechanisms. Epilepsy Res 2024; 199:107282. [PMID: 38134643 DOI: 10.1016/j.eplepsyres.2023.107282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2023] [Revised: 12/08/2023] [Accepted: 12/11/2023] [Indexed: 12/24/2023]
Abstract
BACKGROUND Stroke is the most common cause of newly diagnosed epilepsy in the elderly, ahead of degenerative disorders, brain tumors, and head trauma. Stroke accounts for 30-50% of unprovoked seizures in patients aged ≥ 60 years. This review discusses the current understanding of epidemiology, risk factors, mechanisms, prevention, and treatment opportunities for post-stroke epilepsy (PSE). METHODS We performed a literature search in the PubMed and Cochrane Library databases. The keywords "stroke, epilepsy", "stroke, seizure", "post-stroke seizure", "post-stroke epilepsy" were used to identify the clinical and experimental articles on PSE. All resulting titles and abstracts were evaluated, and any relevant article was considered. The reference lists of all selected papers and reference lists of selected review papers were manually analyzed to find other potentially eligible articles. RESULTS PSE occurs in about 6% of stroke patients within several years after the event. The main risk factors are cortical lesion, initial stroke severity, young age and seizures in acute stroke period (early seizures, ES). Other risk factors, such as a cardioembolic mechanism or circulation territory involvement, remain debated. The role of ES as a risk factor of PSE could be underestimated especially in young age. Mechanism of epileptogenesis may involve gliosis scarring, alteration in synaptic plasticity, etc.; and ES may enhance these processes. Statins especially in the acute period of stroke are possible agents for PSE prevention presumably due to their anticonvulsant and neuroprotection effects. Antiepileptic drugs (AED) monotherapy is enough for seizure prevention in most cases of PSE; but no evidence was found for its efficiency against epileptic foci formation. The growing interest in PSE has led to a notable increase in the number of published articles each year. To aid in navigating this expanding body of literature, several tables are included in the manuscript. CONCLUSION Further studies are needed for better understanding of the pathophysiology of PSE and searching the prevention strategies.
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Affiliation(s)
- Sofia Freiman
- Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russian Federation; Laboratory of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russian Federation.
| | - W Allen Hauser
- Gertrude H. Sergievsky Center, College of Physicians and Surgeons, New York, USA
| | - Flora Rider
- Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russian Federation
| | - Natalia Gulyaeva
- Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russian Federation; Laboratory of Functional Biochemistry of the Nervous System, Institute of Higher Nervous Activity and Neurophysiology, Russian Academy of Sciences, Moscow, Russian Federation
| | - Alla Guekht
- Moscow Research and Clinical Center for Neuropsychiatry of the Healthcare Department of Moscow, Moscow, Russian Federation; Buyanov City Hospital of the Healthcare Department of Moscow, Moscow, Russian Federation; Pirogov Russian National Research Medical University, Moscow, Russian Federation
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Cooper MS, Mackay MT, Shepherd DA, Dagia C, Fahey MC, Reddihough D, Reid SM, Harvey AS. Distinct manifestations and potential mechanisms of seizures due to cortical versus white matter injury in children. Epilepsy Res 2024; 199:107267. [PMID: 38113603 DOI: 10.1016/j.eplepsyres.2023.107267] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 11/24/2023] [Accepted: 11/27/2023] [Indexed: 12/21/2023]
Abstract
PURPOSE To study seizure manifestations and outcomes in children with cortical versus white matter injury, differences potentially explaining variability of epilepsy in children with cerebral palsy. METHODS In this population-based retrospective cohort study, MRIs of children with cerebral palsy due to ischemia or haemorrhage were classified according to presence or absence of cortical injury. MRI findings were then correlated with history of neonatal seizures, seizures during childhood, epilepsy syndromes, and seizure outcomes. RESULTS Of 256 children studied, neonatal seizures occurred in 57 and seizures during childhood occurred in 93. Children with neonatal seizures were more likely to develop seizures during childhood, mostly those with cortical injury. Cortical injury was more strongly associated with (1) developing seizures during childhood, (2) more severe epilepsy syndromes (infantile spasms syndrome, focal epilepsy, Lennox-Gastaut syndrome), and (3) less likelihood of reaching > 2 years without seizures at last follow-up, compared to children without cortical injury. Children without cortical injury, mainly those with white matter injury, were less likely to develop neonatal seizures and seizures during childhood, and when they did, epilepsy syndromes were more commonly febrile seizures and self-limited focal epilepsies of childhood, with most achieving > 2 years without seizures at last follow-up. The presence of cortical injury also influenced seizure occurrence, severity, and outcome within the different predominant injury patterns of the MRI Classification System in cerebral palsy, most notably white matter injury. CONCLUSIONS Epileptogenesis is understood with cortical injury but not well with white matter injury, the latter potentially related to altered postnatal white matter development or myelination leading to apoptosis, abnormal synaptogenesis or altered thalamic connectivity of cortical neurons. These findings, and the potential mechanisms discussed, likely explain the variability of epilepsy in children with cerebral palsy and epilepsy following early-life brain injury in general.
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Affiliation(s)
- Monica S Cooper
- Department of Neurodevelopment & Disability, The Royal Children's Hospital, Melbourne, Victoria, Australia; Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia.
| | - Mark T Mackay
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia; Department of Neurology, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Daisy A Shepherd
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia
| | - Charuta Dagia
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia; Department of Medical Imaging, The Royal Children's Hospital, Melbourne, Victoria, Australia
| | - Michael C Fahey
- Department of Paediatrics, Monash University, Melbourne, Victoria, Australia
| | - Dinah Reddihough
- Department of Neurodevelopment & Disability, The Royal Children's Hospital, Melbourne, Victoria, Australia; Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia
| | - Susan M Reid
- Department of Neurodevelopment & Disability, The Royal Children's Hospital, Melbourne, Victoria, Australia; Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia
| | - A Simon Harvey
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Victoria, Australia; Department of Neurology, The Royal Children's Hospital, Melbourne, Victoria, Australia
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Zhao Y, Zhao W, Han Y. Inhibition of mTORC2 improves brain injury in epileptic rats by promoting chaperone-mediated autophagy. Epilepsy Res 2023; 193:107161. [PMID: 37163909 DOI: 10.1016/j.eplepsyres.2023.107161] [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: 01/06/2023] [Revised: 03/22/2023] [Accepted: 05/01/2023] [Indexed: 05/12/2023]
Abstract
Epilepsy can seriously affect children's cognitive and behavioral development. The mechanistic target of rapamycin(mTOR) pathway plays an important role in neurodevelopment and epilepsy, but the mechanism of mechanistic target of rapamycin complex 2 (mTORC2) in epilepsy is still unclear. Here, we compared the similarities and differences of the mechanisms of action of mechanistic target of rapamycin complex 1 (mTORC1) and mTORC2 complex in the pathogenesis of epilepsy. Our research results show that the levels of apoptosis in cortical and hippocampal neurons were upregulated in epileptic rats (F = 32.15, 30.96; both P < 0.01), and epilepsy caused neuronal damage (F = 8.13, 9.43; both P < 0.01). The mTORC2-Akt pathway was activated in the cortex and hippocampus of epileptic rats. Inhibition of mTORC2 resulted in decreased levels of apoptosis and reduced neuronal damage in the cortex and hippocampus of epileptic rats. In the hippocampus, selective inhibition of mTORC2 increased lysosome-associated membrane protein 2 A (LAMP2A) protein expression compared with the control group, and the difference was statistically significant (F = 3.02, P < 0.05). Finally, we concluded that in the hippocampus, selective inhibition of mTORC2 can improve epileptic brain injury in rats by increasing chaperone-mediated autophagy (CMA) levels.
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Affiliation(s)
- Yihan Zhao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Wenying Zhao
- Department of Pediatrics, Peking University First Hospital, Beijing, China
| | - Ying Han
- Department of Pediatrics, Peking University First Hospital, Beijing, China.
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Crespo M, León-Navarro DA, Martín M. Na +/K +- and Mg 2+-ATPases and Their Interaction with AMPA, NMDA and D 2 Dopamine Receptors in an Animal Model of Febrile Seizures. Int J Mol Sci 2022; 23:ijms232314638. [PMID: 36498965 PMCID: PMC9737571 DOI: 10.3390/ijms232314638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 11/05/2022] [Accepted: 11/15/2022] [Indexed: 11/25/2022] Open
Abstract
Febrile seizures (FS) are one of the most common seizure disorders in childhood which are classified into short and prolonged, depending on their duration. Short FS are usually considered as benign. However, epidemiological studies have shown an association between prolonged FS and temporal lobe epilepsy. The development of animal models of FS has been very useful to investigate the mechanisms and the consequences of FS. One of the most used, the "hair dryer model", has revealed that prolonged FS may lead to temporal lobe epilepsy by altering neuronal function. Several pieces of evidence suggest that Na+/ K+-ATPase and Mg2+-ATPase may play a role in this epileptogenic process. In this work, we found that hyperthermia-induced seizures (HIS) significantly increased the activity of Na+/ K+-ATPase and Mg2+-ATPase five and twenty days after hyperthermic insult, respectively. These effects were diminished in response to AMPA, D2 dopamine A1 and A2A receptors activation, respectively. Furthermore, HIS also significantly increased the protein level of the AMPA subunit GluR1. Altogether, the increased Na+/ K+-ATPase and Mg2+-ATPase agree well with the presence of protective mechanisms. However, the reduction in ATPase activities in the presence of NMDA and AMPA suggest an increased propensity for epileptic events in adults.
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Affiliation(s)
- María Crespo
- Department of Inorganic, Organic Chemistry and Biochemistry, Faculty of Chemical and Technological Sciences, Regional Centre of Biomedical Research (CRIB), Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain
| | - David Agustín León-Navarro
- Department of Inorganic, Organic Chemistry and Biochemistry, Faculty of Chemical and Technological Sciences, Regional Centre of Biomedical Research (CRIB), Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain
- Correspondence: ; Tel.: +34-926-052-114
| | - Mairena Martín
- Department of Inorganic, Organic Chemistry and Biochemistry, Faculty of Chemical and Technological Sciences, School of Medicine of Ciudad Real, Regional Centre of Biomedical Research (CRIB), Universidad de Castilla-La Mancha, 13071 Ciudad Real, Spain
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Early Life Events and Maturation of the Dentate Gyrus: Implications for Neurons and Glial Cells. Int J Mol Sci 2022; 23:ijms23084261. [PMID: 35457079 PMCID: PMC9031216 DOI: 10.3390/ijms23084261] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 12/15/2022] Open
Abstract
The dentate gyrus (DG), an important part of the hippocampus, plays a significant role in learning, memory, and emotional behavior. Factors potentially influencing normal development of neurons and glial cells in the DG during its maturation can exert long-lasting effects on brain functions. Early life stress may modify maturation of the DG and induce lifelong alterations in its structure and functioning, underlying brain pathologies in adults. In this paper, maturation of neurons and glial cells (microglia and astrocytes) and the effects of early life events on maturation processes in the DG have been comprehensively reviewed. Early postnatal interventions affecting the DG eventually result in an altered number of granule neurons in the DG, ectopic location of neurons and changes in adult neurogenesis. Adverse events in early life provoke proinflammatory changes in hippocampal glia at cellular and molecular levels immediately after stress exposure. Later, the cellular changes may disappear, though alterations in gene expression pattern persist. Additional stressful events later in life contribute to manifestation of glial changes and behavioral deficits. Alterations in the maturation of neuronal and glial cells induced by early life stress are interdependent and influence the development of neural nets, thus predisposing the brain to the development of cognitive and psychiatric disorders.
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Postnikova TY, Griflyuk AV, Amakhin DV, Kovalenko AA, Soboleva EB, Zubareva OE, Zaitsev AV. Early Life Febrile Seizures Impair Hippocampal Synaptic Plasticity in Young Rats. Int J Mol Sci 2021; 22:8218. [PMID: 34360983 PMCID: PMC8347828 DOI: 10.3390/ijms22158218] [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: 06/18/2021] [Revised: 07/27/2021] [Accepted: 07/28/2021] [Indexed: 01/04/2023] Open
Abstract
Febrile seizures (FSs) in early life are significant risk factors of neurological disorders and cognitive impairment in later life. However, existing data about the impact of FSs on the developing brain are conflicting. We aimed to investigate morphological and functional changes in the hippocampus of young rats exposed to hyperthermia-induced seizures at postnatal day 10. We found that FSs led to a slight morphological disturbance. The cell numbers decreased by 10% in the CA1 and hilus but did not reduce in the CA3 or dentate gyrus areas. In contrast, functional impairments were robust. Long-term potentiation (LTP) in CA3-CA1 synapses was strongly reduced, which we attribute to the insufficient activity of N-methyl-D-aspartate receptors (NMDARs). Using whole-cell recordings, we found higher desensitization of NMDAR currents in the FS group. Since the desensitization of NMDARs depends on subunit composition, we analyzed NMDAR current decays and gene expression of subunits, which revealed no differences between control and FS rats. We suggest that an increased desensitization is due to insufficient activation of the glycine site of NMDARs, as the application of D-serine, the glycine site agonist, allows the restoration of LTP to a control value. Our results reveal a new molecular mechanism of FS impact on the developing brain.
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Affiliation(s)
| | | | | | | | | | | | - Aleksey V. Zaitsev
- Sechenov Institute of Evolutionary Physiology and Biochemistry of RAS, 44, Toreza Prospekt, 194223 Saint Petersburg, Russia; (T.Y.P.); (A.V.G.); (D.V.A.); (A.A.K.); (E.B.S.); (O.E.Z.)
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Christensen KJ, Dreier JW, Skotte L, Feenstra B, Grove J, Børglum A, Mitrovic M, Cotsapas C, Christensen J. Birth characteristics and risk of febrile seizures. Acta Neurol Scand 2021; 144:51-57. [PMID: 33822360 DOI: 10.1111/ane.13420] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Febrile seizure is a common childhood disorder that affects 2-5% of all children, and is associated with later development of epilepsy and psychiatric disorders. This study determines how the incidence of febrile seizures correlates with birth characteristics, age, sex and brain development. METHODS This is a cohort study of all children born Denmark between 1977 and 2011 who were alive at 3 months of age (N = 2,103,232). The Danish National Patient Register was used to identify children with febrile seizures up to 5 years of age. Follow-up ended on 31 December 2016 when all cohort members had potentially reached 5 years of age. RESULTS In total, 75,593 (3.59%, 95% CI: 3.57-3.62%) were diagnosed with febrile seizures. Incidence peaked at 16.7 months of age (median: 16.7 months, interquartile range: 12.5-24.0). The 5-year cumulative incidence of febrile seizures increased with decreasing birth weight (<1500 g; 5.42% (95% CI: 4.98-5.88% vs. 3,000-4,000 g; 3.53% (95% CI: 3.50-3.56%)) and with decreasing gestational age at birth (31-32 weeks; 5.90% (95% CI: 5.40-6.44%) vs. 39-40 weeks; 3.56% (95% CI: 3.53-3.60)). Lower gestational age at birth was associated with higher age at onset of a first febrile seizure; an association that essentially disappeared when correcting for age from conception. CONCLUSIONS The risk of febrile seizures increased with decreasing birth weight and gestational age at birth. The association between low gestational age at birth and age at first febrile seizure suggests that onset of febrile seizures is associated with the stage of brain development.
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Affiliation(s)
- Kirstine J. Christensen
- Department of Economics and Business Economics National Centre for Register‐Based Research Aarhus BSS Aarhus University Aarhus Denmark
- Department of Neurology Aarhus University Hospital Aarhus Denmark
| | - Julie W. Dreier
- Department of Economics and Business Economics National Centre for Register‐Based Research Aarhus BSS Aarhus University Aarhus Denmark
| | - Line Skotte
- Department of Epidemiology Research Statens Serum Institut Copenhagen Denmark
| | - Bjarke Feenstra
- Department of Epidemiology Research Statens Serum Institut Copenhagen Denmark
| | - Jakob Grove
- Department of Biomedicine Aarhus University Aarhus Denmark
| | - Anders Børglum
- Department of Biomedicine Aarhus University Aarhus Denmark
| | - Mitja Mitrovic
- Department of Neurology Yale School of Medicine New Haven CT USA
| | - Chris Cotsapas
- Department of Neurology Yale School of Medicine New Haven CT USA
| | - Jakob Christensen
- Department of Economics and Business Economics National Centre for Register‐Based Research Aarhus BSS Aarhus University Aarhus Denmark
- Department of Neurology Aarhus University Hospital Aarhus Denmark
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Crespo M, León-Navarro DA, Martín M. Glutamatergic System is Affected in Brain from an Hyperthermia-Induced Seizures Rat Model. Cell Mol Neurobiol 2021; 42:1501-1512. [PMID: 33492599 DOI: 10.1007/s10571-021-01041-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 01/11/2021] [Indexed: 12/22/2022]
Abstract
One of the most frequent neurological disorders in children is febrile seizures (FS), a risk for epilepsy in adults. Glutamate is the main excitatory neurotransmitter in CNS acting through ionotropic and metabotropic receptors. Excess of glutamate in the extracellular space elicits excitotoxicity and has been associated with neurological disorders, such as epilepsy. The removal of extracellular glutamate by excitatory amino acid transporters (EATT) plays an important neuroprotective role. GLT-1 is the main EAAT present in the cortex brain. On the other hand, an increase in metabotropic glutamate receptors 5 (mGlu5R) levels or their overstimulation have been related to the appearance of seizure events in different animal models and in temporal lobe epilepsy in humans. In this work, the status of several components of the glutamatergic system has been analysed in the cortex brain from an FS rat model at short (48 h) and long (20 days) term after hyperthermia-induced seizures. At the short term, we detected increased GLT-1 levels, reduced glutamate concentration, and unchanged mGlu5R levels, without neuronal loss. However, at the long term, an increase in mGlu5R levels together with a decrease in both GLT-1 and glutamate levels were observed. These changes were associated with the appearance of an anxious phenotype. These results suggest a neuroprotective role of the glutamatergic components mGlu5R and GLT-1 at the short term. However, this neuroprotective effect seems to be lost at the long term, leading to an anxious phenotype and suggesting an increased vulnerability and propensity to epileptic events in adults.
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Affiliation(s)
- M Crespo
- Department of Inorganic, Organic and Biochemistry, Faculty of Chemical and Technological Sciences, School of Medicine of Ciudad Real, Universidad de Castilla-La Mancha, Regional Centre of Biomedical Research (CRIB), Avenida Camilo José Cela, 10, 13071, Ciudad Real, Spain
| | - D A León-Navarro
- Department of Inorganic, Organic and Biochemistry, Faculty of Chemical and Technological Sciences, School of Medicine of Ciudad Real, Universidad de Castilla-La Mancha, Regional Centre of Biomedical Research (CRIB), Avenida Camilo José Cela, 10, 13071, Ciudad Real, Spain.
| | - M Martín
- Department of Inorganic, Organic and Biochemistry, Faculty of Chemical and Technological Sciences, School of Medicine of Ciudad Real, Universidad de Castilla-La Mancha, Regional Centre of Biomedical Research (CRIB), Avenida Camilo José Cela, 10, 13071, Ciudad Real, Spain
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Rosiles-Abonce A, Rubio C, Taddei E, Rosiles D, Rubio-Osornio M. Antiepileptogenic Effect of Retinoic Acid. Curr Neuropharmacol 2021; 19:383-391. [PMID: 32351181 PMCID: PMC8033965 DOI: 10.2174/1570159x18666200429232104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/17/2020] [Accepted: 04/24/2020] [Indexed: 11/24/2022] Open
Abstract
Retinoic acid, a metabolite of vitamin A, acts through either genomic or nongenomic actions. The genomic action of retinoids exerts effects on gene transcription through interaction with retinoid receptors such as retinoic acid receptors (RARα, β, and γ) and retinoid X receptors (RXRα, β, and γ) that are primarily concentrated in the amygdala, pre-frontal cortex, and hippocampal areas in the brain. In response to retinoid binding, RAR/RXR heterodimers undergo major conformational changes and orchestrate the transcription of specific gene networks. Previous experimental studies have reported that retinoic acid exerts an antiepileptogenic effect through diverse mechanisms, including the modulation of gap junctions, neurotransmitters, long-term potentiation, calcium channels and some genes. To our knowledge, there are no previous or current clinical trials evaluating the use of retinoic acid for seizure control.
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Affiliation(s)
| | | | | | | | - Moisés Rubio-Osornio
- Address correspondence to this author at the Laboratorio Experimental de Enfermedades Neurodegenerativas, Instituto Nacional de Neurología y Neurocirugía, Ciudad de Mexico; E-mail:
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Perez C, Felix L, Durry S, Rose CR, Ullah G. On the origin of ultraslow spontaneous Na + fluctuations in neurons of the neonatal forebrain. J Neurophysiol 2020; 125:408-425. [PMID: 33236936 DOI: 10.1152/jn.00373.2020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Spontaneous neuronal and astrocytic activity in the neonate forebrain is believed to drive the maturation of individual cells and their integration into complex brain-region-specific networks. The previously reported forms include bursts of electrical activity and oscillations in intracellular Ca2+ concentration. Here, we use ratiometric Na+ imaging to demonstrate spontaneous fluctuations in the intracellular Na+ concentration of CA1 pyramidal neurons and astrocytes in tissue slices obtained from the hippocampus of mice at postnatal days 2-4 (P2-4). These occur at very low frequency (∼2/h), can last minutes with amplitudes up to several millimolar, and mostly disappear after the first postnatal week. To further investigate their mechanisms, we model a network consisting of pyramidal neurons and interneurons. Experimentally observed Na+ fluctuations are mimicked when GABAergic inhibition in the simulated network is made depolarizing. Both our experiments and computational model show that blocking voltage-gated Na+ channels or GABAergic signaling significantly diminish the neuronal Na+ fluctuations. On the other hand, blocking a variety of other ion channels, receptors, or transporters including glutamatergic pathways does not have significant effects. Our model also shows that the amplitude and duration of Na+ fluctuations decrease as we increase the strength of glial K+ uptake. Furthermore, neurons with smaller somatic volumes exhibit fluctuations with higher frequency and amplitude. As opposed to this, larger extracellular to intracellular volume ratio observed in neonatal brain exerts a dampening effect. Finally, our model predicts that these periods of spontaneous Na+ influx leave neonatal neuronal networks more vulnerable to seizure-like states when compared with mature brain.NEW & NOTEWORTHY Spontaneous activity in the neonate forebrain plays a key role in cell maturation and brain development. We report spontaneous, ultraslow, asynchronous fluctuations in the intracellular Na+ concentration of neurons and astrocytes. We show that this activity is not correlated with the previously reported synchronous neuronal population bursting or Ca2+ oscillations, both of which occur at much faster timescales. Furthermore, extracellular K+ concentration remains nearly constant. The spontaneous Na+ fluctuations disappear after the first postnatal week.
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Affiliation(s)
- Carlos Perez
- Department of Physics, University of South Florida, Tampa, Florida
| | - Lisa Felix
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Simone Durry
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Christine R Rose
- Faculty of Mathematics and Natural Sciences, Institute of Neurobiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Ghanim Ullah
- Department of Physics, University of South Florida, Tampa, Florida
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Polat İ, Yiş U, Ayanoğlu M, Okur D, Edem P, Paketçi C, Bayram E, Hız Kurul S. Risk Factors of Post-Stroke Epilepsy in Children; Experience from a Tertiary Center and a Brief Review of the Literature. J Stroke Cerebrovasc Dis 2020; 30:105438. [PMID: 33197802 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105438] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 10/02/2020] [Accepted: 10/29/2020] [Indexed: 11/15/2022] Open
Abstract
OBJECTIVES Acute seizures and post-stroke epilepsy have been reported more frequently in patients with pediatric stroke than adults. Acute seizures in the first days of a stroke may deteriorate stroke and ischemia-related neurodegeneration and contribute to the development of post-stroke epilepsy. In this study, we aimed to investigate risk factors for the development of post-stroke epilepsy in children with arterial ischemic stroke. MATERIALS AND METHODS We recruited 86 children with arterial ischemic stroke. We analyzed variables, including age at admission, gender, complaints at presentation, focal or diffuse neurologic signs, neurologic examination findings, laboratory investigations that were conducted at admission with stroke (complete blood cell count, biochemical-infectious-metabolic-immunological investigations, vitamin B12 levels, vitamin D levels), neuroimaging results, etiologies, time of the first seizure, time of remote seizures, and development of neurologic deficit retrospectively. Seizures during the first six hours after stroke onset were defined as 'very early seizures'. 'Early seizures' were referred to seizures during the first 48 h. Patients who experienced two or more seizures that occurred after the acute phase of seizures were classified as 'epileptic.' A binary logistic regression analysis was used to estimate risk factors. RESULTS An acute seizure was detected in 59% and post-stroke epilepsy developed in 41% of our cohort. Binary logistic regression analysis demonstrated that 'very early seizures' increased epilepsy risk six-fold. Epilepsy was 16 times higher in patients with 'early seizures'. Low vitamin D levels were defined as a risk factor for post-stroke epilepsy. CONCLUSION Seizures in the very early period (within the first six hours) are the most significant risk factors for the development of post-stroke epilepsy Further studies regarding seizure prevention and neuroprotective therapies are needed because post-stroke epilepsy will affect long term prognosis in patients with pediatric stroke.
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Affiliation(s)
- İpek Polat
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Uluç Yiş
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Müge Ayanoğlu
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Derya Okur
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Pınar Edem
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Cem Paketçi
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Erhan Bayram
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
| | - Semra Hız Kurul
- Department of Pediatric Neurology, Dokuz Eylul University, Faculty of Medicine, İzmir, Narlıdere, Turkey.
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Crespo M, León‐Navarro DA, Ruíz MÁ, Martín M. Hyperthermia‐induced seizures produce long‐term effects on the functionality of adenosine A
1
receptor in rat cerebral cortex. Int J Dev Neurosci 2020; 80:1-12. [DOI: 10.1002/jdn.10000] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Accepted: 12/09/2019] [Indexed: 12/12/2022] Open
Affiliation(s)
- María Crespo
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
| | - David Agustín León‐Navarro
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
| | - María Ángeles Ruíz
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
| | - Mairena Martín
- Departamento de Química Inorgánica Orgánica y Bioquímica Facultad de Ciencias y Tecnologías Químicas Facultad de Medicina de Ciudad Real Centro Regional de Investigaciones Biomédicas Universidad de Castilla‐La Mancha Ciudad Real Spain
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Crespo M, León-Navarro DA, Martín M. Early-life hyperthermic seizures upregulate adenosine A 2A receptors in the cortex and promote depressive-like behavior in adult rats. Epilepsy Behav 2018; 86:173-178. [PMID: 30017837 DOI: 10.1016/j.yebeh.2018.06.048] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Revised: 06/07/2018] [Accepted: 06/25/2018] [Indexed: 10/28/2022]
Abstract
Febrile seizures (FS) represent one of the most frequent convulsive disorders in children which can be classified into simple and prolonged depending on the duration. Although simple FS are generally considered as benign, there is controversy about the outcome of prolonged FS. Here, we have used an animal model of prolonged FS to investigate persistent neurochemical and behavioral alterations in adult rats. Hyperthermic seizures were induced in 12-day-old rats using a warmed air stream from a hair dryer. Neonates exhibited arrest of heat-induced hyperkinesis followed by body flexion and rearing and falling over associated with hindlimb clonus seizures (stage 5 on Racine scale criteria) after hyperthermic induction. After 48 days, the animals were assayed on dark-light box and forced swim tests in order to detect if rats will show signs of anxiety or depression. Finally, animals were sacrificed 56 days after hyperthermia-induced seizures (HIS), and their effects on adenosine A2A receptor signaling and 5'-nucleotidase activity were studied in plasma membranes from the cerebral cortex by using radioligand-binding assay and by measuring the activities of adenylate cyclase and 5'-nucleotidase. Results obtained have shown that adult rats submitted to HIS during the neonatal period showed depressive-like behavior. Furthermore, animals exposed to hyperthermic insult showed an increase in A2A receptor level which was also accompanied by an increase in A2A receptor functionality.
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Affiliation(s)
- María Crespo
- Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Ciencias y Tecnologías Químicas/Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain
| | - David Agustín León-Navarro
- Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Ciencias y Tecnologías Químicas/Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain.
| | - Mairena Martín
- Departamento de Química Inorgánica, Orgánica y Bioquímica, Facultad de Ciencias y Tecnologías Químicas/Facultad de Medicina de Ciudad Real, Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Avenida Camilo José Cela, 10, 13071 Ciudad Real, Spain
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15
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Rozmer K, Gao P, Araújo MGL, Khan MT, Liu J, Rong W, Tang Y, Franke H, Krügel U, Fernandes MJS, Illes P. Pilocarpine-Induced Status Epilepticus Increases the Sensitivity of P2X7 and P2Y1 Receptors to Nucleotides at Neural Progenitor Cells of the Juvenile Rodent Hippocampus. Cereb Cortex 2018; 27:3568-3585. [PMID: 27341850 DOI: 10.1093/cercor/bhw178] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Patch-clamp recordings indicated the presence of P2X7 receptors at neural progenitor cells (NPCs) in the subgranular zone of the dentate gyrus in hippocampal brain slices prepared from transgenic nestin reporter mice. The activation of these receptors caused inward current near the resting membrane potential of the NPCs, while P2Y1 receptor activation initiated outward current near the reversal potential of the P2X7 receptor current. Both receptors were identified by biophysical/pharmacological methods. When the brain slices were prepared from mice which underwent a pilocarpine-induced status epilepticus or when brain slices were incubated in pilocarpine-containing external medium, the sensitivity of P2X7 and P2Y1 receptors was invariably increased. Confocal microscopy confirmed the localization of P2X7 and P2Y1 receptor-immunopositivity at nestin-positive NPCs. A one-time status epilepticus in rats caused after a latency of about 5 days recurrent epileptic fits. The blockade of central P2X7 receptors increased the number of seizures and their severity. It is hypothesized that P2Y1 receptors after a status epilepticus may increase the ATP-induced proliferation/ectopic migration of NPCs; the P2X7 receptor-mediated necrosis/apoptosis might counteract these effects, which would otherwise lead to a chronic manifestation of recurrent epileptic fits.
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Affiliation(s)
- Katalin Rozmer
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany
| | - Po Gao
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany.,Department of Physiology, Shanghai Jiaotong University School of Medicine, 200025 Shanghai, China
| | - Michelle G L Araújo
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia da Universidade Federal de São Paulo, São Paulo/SP, Brazil
| | - Muhammad Tahir Khan
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany
| | - Juan Liu
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany.,Acupuncture and Tuina School, Chengdu University of TCM, 610075 Chengdu, China
| | - Weifang Rong
- Department of Physiology, Shanghai Jiaotong University School of Medicine, 200025 Shanghai, China
| | - Yong Tang
- Acupuncture and Tuina School, Chengdu University of TCM, 610075 Chengdu, China
| | - Heike Franke
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany
| | - Ute Krügel
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany
| | - Maria José S Fernandes
- Disciplina de Neurociência, Departamento de Neurologia e Neurocirurgia da Universidade Federal de São Paulo, São Paulo/SP, Brazil
| | - Peter Illes
- Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universität Leipzig, 04107 Leipzig, Germany
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Crespo M, León-Navarro DA, Martín M. Cerebellar oxidative stress and fine motor impairment in adolescent rats exposed to hyperthermia-induced seizures is prevented by maternal caffeine intake during gestation and lactation. Eur J Pharmacol 2018; 822:186-198. [DOI: 10.1016/j.ejphar.2018.01.023] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Revised: 01/12/2018] [Accepted: 01/17/2018] [Indexed: 12/17/2022]
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17
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Niu M, Han Y, Li Q, Zhang J. Endogenous sulfur dioxide regulates hippocampal neuron apoptosis in developing epileptic rats and is associated with the PERK signaling pathway. Neurosci Lett 2018; 665:22-28. [DOI: 10.1016/j.neulet.2017.11.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/15/2017] [Accepted: 11/15/2017] [Indexed: 01/15/2023]
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18
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Pisani F, Pavlidis E, Facini C, La Morgia C, Fusco C, Cantalupo G. A 15-year epileptogenic period after perinatal brain injury. FUNCTIONAL NEUROLOGY 2017; 32:49-53. [PMID: 28380324 DOI: 10.11138/fneur/2017.32.1.049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Seizures are a frequent acute neurological event in the neonatal period. Up to 12 to 18% of all seizures in newborns are due to perinatal stroke and up to 39% of affected children can then develop epilepsy in childhood. We report the case of a young patient who presented stroke-related seizures in the neonatal period and then developed focal symptomatic epilepsy at 15 years of age, and in whom the epileptic focus was found to co-localize with the site of his ischemic brain lesion. Such a prolonged silent period before onset of remote symptomatic epilepsy has not previously been reported. This case suggests that newborns with seizures due to a neonatal stroke are at higher risk of epilepsy and that the epileptogenic process in these subjects can last longer than a decade.
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Animal Models of Seizures and Epilepsy: Past, Present, and Future Role for the Discovery of Antiseizure Drugs. Neurochem Res 2017; 42:1873-1888. [PMID: 28290134 DOI: 10.1007/s11064-017-2222-z] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 03/01/2017] [Accepted: 03/02/2017] [Indexed: 12/14/2022]
Abstract
The identification of potential therapeutic agents for the treatment of epilepsy requires the use of seizure models. Except for some early treatments, including bromides and phenobarbital, the antiseizure activity of all clinically used drugs was, for the most part, defined by acute seizure models in rodents using the maximal electroshock and subcutaneous pentylenetetrazole seizure tests and the electrically kindled rat. Unfortunately, the clinical evidence to date would suggest that none of these models, albeit useful, are likely to identify those therapeutics that will effectively manage patients with drug resistant seizures. Over the last 30 years, a number of animal models have been developed that display varying degrees of pharmacoresistance, such as the phenytoin- or lamotrigine-resistant kindled rat, the 6-Hz mouse model of partial seizures, the intrahippocampal kainate model in mice, or rats in which spontaneous recurrent seizures develops after inducing status epilepticus by chemical or electrical stimulation. As such, these models can be used to study mechanisms of drug resistance and may provide a unique opportunity for identifying a truly novel antiseizure drug (ASD), but thus far clinical evidence for this hope is lacking. Although animal models of drug resistant seizures are now included in ASD discovery approaches such as the ETSP (epilepsy therapy screening program), it is important to note that no single model has been validated for use to identify potential compounds for as yet drug resistant seizures, but rather a battery of such models should be employed, thus enhancing the sensitivity to discover novel, highly effective ASDs. The present review describes the previous and current approaches used in the search for new ASDs and offers some insight into future directions incorporating new and emerging animal models of therapy resistance.
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20
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Fox CK, Mackay MT, Dowling MM, Pergami P, Titomanlio L, Deveber G. Prolonged or recurrent acute seizures after pediatric arterial ischemic stroke are associated with increasing epilepsy risk. Dev Med Child Neurol 2017; 59:38-44. [PMID: 27422813 PMCID: PMC7007772 DOI: 10.1111/dmcn.13198] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 06/01/2016] [Indexed: 11/29/2022]
Abstract
AIM To determine epilepsy risk factors after pediatric stroke. METHOD A cohort of children with arterial ischemic stroke (birth-18y) was enrolled at 21 centers and followed for 1 year. Acute seizures (≤7d after stroke) and active epilepsy (at least one unprovoked remote seizure plus maintenance anticonvulsant at 1y) were identified. Predictors were determined using logistic regression. RESULTS Among 114 patients (28 neonates and 86 children) enrolled, 26 neonates (93%) and 32 children (37%) had an acute seizure. Acute seizures lasted longer than 5 minutes in 23 patients (40%) and were frequently recurrent: 33 (57%) had 2 to 10 seizures and 11 (19%) had more than 10. Among 109 patients with 1-year follow-up, 11 (10%) had active epilepsy. For each year younger, active epilepsy was 20% more likely (odds ratio [OR] 0.8, 95% confidence interval [CI] 0.6-0.99, p=0.041). Prolonged or recurrent acute seizures also increased epilepsy risk. Each additional 10 minutes of the longest acute seizure increased epilepsy risk fivefold (OR 4.7, 95% CI 1.7-13). Patients with more than 10 acute seizures had a 30-fold increased epilepsy risk (OR 30, 95% CI 2.9-305). INTERPRETATION Pediatric stroke survivors, especially younger children, have a high risk of epilepsy 1 year after stroke. Prolonged or recurrent acute seizures increase epilepsy risk in a dose-dependent manner.
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Affiliation(s)
- Christine K Fox
- Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA, USA
| | - Mark T Mackay
- Department of Neurology, Royal Children's Hospital, Melbourne, Vic., Australia
- Murdoch Children's Research Institute, Melbourne, Vic., Australia
| | - Michael M Dowling
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Paola Pergami
- Department of Neurology, Children's National Medical Center, Washington, DC, USA
| | - Luigi Titomanlio
- Pediatric Migraine and Neurovascular Diseases Clinic, Robert Debrè Hospital, Paris, France
| | - Gabrielle Deveber
- Division of Neurology, Department of Pediatrics, Hospital for Sick Children, University of Toronto, Toronto, ON, Canada
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21
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Fit for purpose application of currently existing animal models in the discovery of novel epilepsy therapies. Epilepsy Res 2016; 126:157-84. [PMID: 27505294 DOI: 10.1016/j.eplepsyres.2016.05.016] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 03/06/2016] [Accepted: 05/30/2016] [Indexed: 01/10/2023]
Abstract
Animal seizure and epilepsy models continue to play an important role in the early discovery of new therapies for the symptomatic treatment of epilepsy. Since 1937, with the discovery of phenytoin, almost all anti-seizure drugs (ASDs) have been identified by their effects in animal models, and millions of patients world-wide have benefited from the successful translation of animal data into the clinic. However, several unmet clinical needs remain, including resistance to ASDs in about 30% of patients with epilepsy, adverse effects of ASDs that can reduce quality of life, and the lack of treatments that can prevent development of epilepsy in patients at risk following brain injury. The aim of this review is to critically discuss the translational value of currently used animal models of seizures and epilepsy, particularly what animal models can tell us about epilepsy therapies in patients and which limitations exist. Principles of translational medicine will be used for this discussion. An essential requirement for translational medicine to improve success in drug development is the availability of animal models with high predictive validity for a therapeutic drug response. For this requirement, the model, by definition, does not need to be a perfect replication of the clinical condition, but it is important that the validation provided for a given model is fit for purpose. The present review should guide researchers in both academia and industry what can and cannot be expected from animal models in preclinical development of epilepsy therapies, which models are best suited for which purpose, and for which aspects suitable models are as yet not available. Overall further development is needed to improve and validate animal models for the diverse areas in epilepsy research where suitable fit for purpose models are urgently needed in the search for more effective treatments.
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van Dijkman SC, Alvarez-Jimenez R, Danhof M, Della Pasqua O. Pharmacotherapy in pediatric epilepsy: from trial and error to rational drug and dose selection - a long way to go. Expert Opin Drug Metab Toxicol 2016; 12:1143-56. [PMID: 27434782 DOI: 10.1080/17425255.2016.1203900] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
INTRODUCTION Whereas ongoing efforts in epilepsy research focus on the underlying disease processes, the lack of a physiologically based rationale for drug and dose selection contributes to inadequate treatment response in children. In fact, limited information on the interindividual variation in pharmacokinetics and pharmacodynamics of anti-epileptic drugs (AEDs) in children drive prescription practice, which relies primarily on dose regimens according to a mg/kg basis. Such practice has evolved despite advancements in pediatric pharmacology showing that growth and maturation processes do not correlate linearly with changes in body size. AREAS COVERED In this review we aim to provide 1) a comprehensive overview of the sources of variability in the response to AEDs, 2) insight into novel methodologies to characterise such variation and 3) recommendations for treatment personalisation. EXPERT OPINION The use of pharmacokinetic-pharmacodynamic principles in clinical practice is hindered by the lack of biomarkers and by practical constraints in the evaluation of polytherapy. The identification of biomarkers and their validation as tools for drug development and therapeutics will require some time. Meanwhile, one should not miss the opportunity to integrate the available pharmacokinetic data with modeling and simulation concepts to prevent further delays in the development of personalised treatments for pediatric patients.
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Affiliation(s)
- Sven C van Dijkman
- a Division of Pharmacology , Leiden Academic Centre for Drug Research , Leiden , The Netherlands
| | - Ricardo Alvarez-Jimenez
- a Division of Pharmacology , Leiden Academic Centre for Drug Research , Leiden , The Netherlands
| | - Meindert Danhof
- a Division of Pharmacology , Leiden Academic Centre for Drug Research , Leiden , The Netherlands
| | - Oscar Della Pasqua
- b Clinical Pharmacology and Discovery Medicine , GlaxoSmithKline , Stockley Park , UK.,c Clinical Pharmacology and Therapeutics , University College London , London , UK
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Löscher W, Hirsch LJ, Schmidt D. The enigma of the latent period in the development of symptomatic acquired epilepsy - Traditional view versus new concepts. Epilepsy Behav 2015; 52:78-92. [PMID: 26409135 DOI: 10.1016/j.yebeh.2015.08.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 08/30/2015] [Indexed: 01/21/2023]
Abstract
A widely accepted hypothesis holds that there is a seizure-free, pre-epileptic state, termed the "latent period", between a brain insult, such as traumatic brain injury or stroke, and the onset of symptomatic epilepsy, during which a cascade of structural, molecular, and functional alterations gradually mediates the process of epileptogenesis. This review, based on recent data from both animal models and patients with different types of brain injury, proposes that epileptogenesis and often subclinical epilepsy can start immediately after brain injury without any appreciable latent period. Even though the latent period has traditionally been the cornerstone concept representing epileptogenesis, we suggest that the evidence for the existence of a latent period is spotty both for animal models and human epilepsy. Knowing whether a latent period exists or not is important for our understanding of epileptogenesis and for the discovery and the trial design of antiepileptogenic agents. The development of antiepileptogenic treatments to prevent epilepsy in patients at risk from a brain insult is a major unmet clinical need.
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Affiliation(s)
- 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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Wolfart J, Laker D. Homeostasis or channelopathy? Acquired cell type-specific ion channel changes in temporal lobe epilepsy and their antiepileptic potential. Front Physiol 2015; 6:168. [PMID: 26124723 PMCID: PMC4467176 DOI: 10.3389/fphys.2015.00168] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Accepted: 05/19/2015] [Indexed: 01/16/2023] Open
Abstract
Neurons continuously adapt the expression and functionality of their ion channels. For example, exposed to chronic excitotoxicity, neurons homeostatically downscale their intrinsic excitability. In contrast, the “acquired channelopathy” hypothesis suggests that proepileptic channel characteristics develop during epilepsy. We review cell type-specific channel alterations under different epileptic conditions and discuss the potential of channels that undergo homeostatic adaptations, as targets for antiepileptic drugs (AEDs). Most of the relevant studies have been performed on temporal lobe epilepsy (TLE), a widespread AED-refractory, focal epilepsy. The TLE patients, who undergo epilepsy surgery, frequently display hippocampal sclerosis (HS), which is associated with degeneration of cornu ammonis subfield 1 pyramidal cells (CA1 PCs). Although the resected human tissue offers insights, controlled data largely stem from animal models simulating different aspects of TLE and other epilepsies. Most of the cell type-specific information is available for CA1 PCs and dentate gyrus granule cells (DG GCs). Between these two cell types, a dichotomy can be observed: while DG GCs acquire properties decreasing the intrinsic excitability (in TLE models and patients with HS), CA1 PCs develop channel characteristics increasing intrinsic excitability (in TLE models without HS only). However, thorough examination of data on these and other cell types reveals the coexistence of protective and permissive intrinsic plasticity within neurons. These mechanisms appear differentially regulated, depending on the cell type and seizure condition. Interestingly, the same channel molecules that are upregulated in DG GCs during HS-related TLE, appear as promising targets for future AEDs and gene therapies. Hence, GCs provide an example of homeostatic ion channel adaptation which can serve as a primer when designing novel anti-epileptic strategies.
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Affiliation(s)
- Jakob Wolfart
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Debora Laker
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
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Florek-Luszczki M, Zagaja M, Luszczki JJ. Influence of WIN 55,212-2 on the anticonvulsant and acute neurotoxic potential of clobazam and lacosamide in the maximal electroshock-induced seizure model and chimney test in mice. Epilepsy Res 2014; 108:1728-33. [DOI: 10.1016/j.eplepsyres.2014.10.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/24/2014] [Accepted: 10/01/2014] [Indexed: 01/29/2023]
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Pavlidou E, Panteliadis C. Prognostic factors for subsequent epilepsy in children with febrile seizures. Epilepsia 2013; 54:2101-7. [PMID: 24304433 DOI: 10.1111/epi.12429] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/20/2013] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Epilepsy following febrile seizures (FS) has been estimated between 2% and 7%. It concerns a prospective study in a large sample of children with a long-term follow-up. The aim of this study is to identify the prognostic factors that can lead children with FS to epilepsy. METHODS Children with a first episode of FS were included. We gathered information about prenatal and perinatal history, family history of FS and epilepsy in first- and second degree relatives, age at the time of the initial FS, dates of FS recurrences, focality, duration of the FS and recurrent episodes within the same febrile illness, height and duration of fever prior to the seizure, cause of the fever, and frequency of febrile illnesses. Patients were seen every 4-6 months and also at each recurrence. KEY FINDINGS A group of 560 children with a first FS met all entry criteria. Epilepsy was recorded at 5.4%. Statistical analysis was performed between children with epilepsy and those with no afebrile seizure. We analyzed FS recurrences in accordance with the occurrence of epilepsy. From the third FS recurrence and beyond, only focality continued to have prognostic value. SIGNIFICANCE Main prognostic factors for the development of epilepsy after FS are: (1) complex FS that increased the risk for epilepsy 3.6 times, (2) age at onset of FS beyond the third year of life that raised the risk 3.8 times, (3) positive family history of epilepsy 7.3 times, and (4) multiple episodes of FS about 10 times. Focality at the first and the second FS recurrence increased the risk of epilepsy about 9.7 and 11.7 times, respectively. Focality was the only factor that continued to be significant in further FS recurrences. A prognostic profile of each child with FS would be very useful for the follow-up of these children.
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Affiliation(s)
- Efterpi Pavlidou
- Pediatric Neurology Department, A.H.E.P.A Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
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Gosselin D, Bellavance MA, Rivest S. IL-1RAcPb signaling regulates adaptive mechanisms in neurons that promote their long-term survival following excitotoxic insults. Front Cell Neurosci 2013; 7:9. [PMID: 23423359 PMCID: PMC3573345 DOI: 10.3389/fncel.2013.00009] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Accepted: 01/28/2013] [Indexed: 01/11/2023] Open
Abstract
Excitotoxicity is a major component of neurodegenerative diseases and is typically accompanied by an inflammatory response. Cytokines IL-1alpha and IL-1beta are key regulators of this inflammatory response and modulate the activity of numerous cell types, including neurons. IL-1RAcPb is an isoform of IL-1RAcP expressed specifically in neurons and promotes their survival during acute inflammation. Here, we investigated in vivo whether IL-1RAcPb also promotes neuronal survival in a model of excitotoxicity. Intrastriatal injection of kainic acid (KA) in mice caused a strong induction of IL-1 cytokines mRNA in the brain. The stress response of cortical neurons at 12 h post-injection, as measured by expression of Atf3, FoxO3a, and Bdnf mRNAs, was similar in WT and AcPb-deficient mice. Importantly however, a delayed upregulation in the transcription of calpastatin was significantly higher in WT than in AcPb-deficient mice. Finally, although absence of AcPb signaling had no effect on damage to neurons in the cortex at early time points, it significantly impaired their long-term survival. These data suggest that in a context of excitotoxicity, stimulation of IL-1RAcPb signaling may promote the activity of a key neuroprotective mechanism.
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Affiliation(s)
- David Gosselin
- Faculty of Medicine, Neuroscience Laboratory, CHU de Québec Research Center and Department of Molecular Medicine, Laval University Quebec City, QC, Canada
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Neuronal injury and cytogenesis after simple febrile seizures in the hippocampal dentate gyrus of juvenile rat. Childs Nerv Syst 2012; 28:1931-6. [PMID: 22661146 DOI: 10.1007/s00381-012-1817-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Accepted: 05/18/2012] [Indexed: 10/28/2022]
Abstract
PURPOSE Although simple febrile seizures are frequently described as harmless, there is evidence which suggests that hippocampal damage may occur after simple febrile seizures. This study aimed to investigate possible neuronal damages as well as alterations in cytogenesis in the hippocampal dentate gyrus following simple febrile seizures. METHODS Simple febrile seizure was modeled by hyperthermia-induced seizures in 22-day-old male rats. The brains were removed 2 or 15 days after hyperthermia in all rats with (n=20) and without (n=10) occurrence of seizures as well as in control animals (n=10). The sections were stained with hematoxylin and eosin to estimate the surface numerical density of dark neurons. Ki-67 immunohistochemistry was performed to evaluate changes of cytogenesis following simple febrile seizures. RESULTS Hyperthermia induced behavioral seizure activities in 67 % of the rats. The numerical densities of dark neurons as well as the mean Ki-67 index (the fraction of Ki-67-positive cells) were significantly increased in dentate gyrus after induction of seizures by hyperthermia compared to both controls and rats without seizure after hyperthermia. Both the seizure duration and intensity were correlated significantly with numerical densities of dark neurons (but not with Ki-67 index). CONCLUSION The data indicate that simple febrile seizures can cause neuronal damages and enhancement of cytogenesis in the hippocampal dentate gyrus, which were still visible for at least 2 weeks. These findings also suggest the correlation of febrile seizure intensity and duration with neuronal damage.
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Abstract
Epilepsy is a common neurological disorder that is complicated by psychiatric, cognitive, and social comorbidities that have become a major target of concern and investigation in view of their adverse effect on the course and quality of life. In this report we define the specific psychiatric, cognitive, and social comorbidities of paediatric and adult epilepsy, their epidemiology, and real life effects; examine the relation between epilepsy syndromes and the risk of neurobehavioural comorbidities; address the lifespan effect of epilepsy on brain neurodevelopment and brain ageing and the risk of neurobehavioural comorbidities; consider the overarching effect of broader brain disorders on both epilepsy and neurobehavioural comorbidities; examine directions of causality and the contribution of selected epilepsy-related characteristics; and outline clinic-friendly screening approaches for these problems and recommended pharmacological, behavioural, and educational interventions.
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Affiliation(s)
- Jack J. Lin
- Department of Neurology, University of California at Irvine, Irvine, California, USA
| | - Marco Mula
- Amedeo Avogadro University, Novara, Italy
| | - Bruce P. Hermann
- Department of Neurology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
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Abstract
BACKGROUND Seizures are one of the most common symptoms of acute neurological disorders in newborns. This study aimed at evaluating predictors of epilepsy in newborns with neonatal seizures. METHODS We recruited consecutively 85 neonates with repeated neonatal video-electroencephalogram (EEG)-confirmed seizures between January 1999 and December 2004. The relationship between clinical, EEG, and ultrasound (US) data in the neonatal period and the development of postneonatal epilepsy was investigated at 7 y of age. RESULTS Fifteen patients (17.6%) developed postneonatal epilepsy. Partial or no response to anticonvulsant therapy (odds ratio (OR) 16.7, 95% confidence interval (CI): 1.8-155.8, P = 0.01; OR 47, 95% CI: 5.2-418.1, P < 0.01, respectively), severely abnormal cerebral US scan findings (OR: 5.4; 95% CI: 1.1-27.4; P < 0.04), severely abnormal EEG background activity (OR: 9.5; 95% CI: 1.6-54.2; P = 0.01), and the presence of status epilepticus (OR: 6.1; 95% CI: 1.8-20.3; P < 0.01) were found to be predictors of epilepsy. However, only the response to therapy seemed to be an independent predictor of postneonatal epilepsy. CONCLUSION Neonatal seizures seem to be related to postneonatal epilepsy. Recurrent and prolonged neonatal seizures may act on an epileptogenic substrate, causing further damage, which is responsible for the subsequent clinical expression of epilepsy.
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Berger I, Dor T, Halvardson J, Edvardson S, Shaag A, Feuk L, Elpeleg O. Intractable epilepsy of infancy due to homozygous mutation in the EFHC1 gene. Epilepsia 2012; 53:1436-40. [DOI: 10.1111/j.1528-1167.2012.03536.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Libbey JE, Fujinami RS. Neurotropic viral infections leading to epilepsy: focus on Theiler's murine encephalomyelitis virus. Future Virol 2011; 6:1339-1350. [PMID: 22267964 PMCID: PMC3259611 DOI: 10.2217/fvl.11.107] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Neurotropic viruses cause viral encephalitis and are associated with the development of seizures/epilepsy. The first infection-driven animal model for epilepsy, the Theiler's murine encephalomyelitis virus-induced seizure model is described herein. Intracerebral infection of C57BL/6 mice with Theiler's murine encephalomyelitis virus induces acute seizures from which the animals recover. However, once the virus is cleared, a significant portion of the animals that experienced acute seizures later develop epilepsy. Components of the innate immune response to viral infection, including IL-6 and complement component 3, have been implicated in the development of acute seizures. Multiple mechanisms, including neuronal cell destruction and cytokine activation, play a role in the development of acute seizures. Future studies targeting the innate immune response will lead to new therapies for seizures/epilepsy.
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Affiliation(s)
- Jane E Libbey
- Department of Pathology, University of Utah, 30 North 1900 East, 3R330 SOM, Salt Lake City, UT 84132, USA
| | - Robert S Fujinami
- Department of Pathology, University of Utah, 30 North 1900 East, 3R330 SOM, Salt Lake City, UT 84132, USA
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Dudek FE, Ekstrand JJ, Staley KJ. Is neuronal death necessary for acquired epileptogenesis in the immature brain? Epilepsy Curr 2011; 10:95-9. [PMID: 20697505 DOI: 10.1111/j.1535-7511.2010.01369.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
A central question concerning acquired epileptogenesis in the immature brain is whether neuronal death is required for the development of epilepsy after a brain insult. Results from three different animal models of brain injury during early development have been used to develop the hypothesis that status epilepticus, prolonged febrile seizures, or hypoxia-induced seizures can lead to chronic epilepsy without the occurrence of neuronal death. This brief review will summarize the evidence supporting the hypothesis in each model and then critique the data and published interpretations. A case will be made that the evidence to date neither rules out the occurrence of neuronal death nor demonstrates that epileptogenesis (i.e., spontaneous recurrent seizures) has actually occurred in these animal models of acquired pediatric epilepsy. We also review evidence for the opposing hypothesis: acquired epileptogenesis in the immature brain requires, or at least often involves, neuronal death.
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Affiliation(s)
- F Edward Dudek
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, UT.
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Huneau C, Demont-Guignard S, Benquet P, Martin B, Wendling F. Time-domain features of epileptic spikes as potential bio-markers of the epileptogenesis process. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2011; 2010:6007-10. [PMID: 21097111 DOI: 10.1109/iembs.2010.5627592] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Epilepsy is a neurological disorder characterized by recurrent seizures which affects about 1% people worldwide. During the past decades, some mechanisms involved in ictogenesis (generation of seizures) have been identified and, to some extent, partially understood. However, regarding epileptogenesis (process by which a neuronal system becomes epileptic), underlying mechanisms remain elusive. This difficulty is mostly related to the fact that epileptogenesis can only be addressed using experimental models. In this study, we have analyzed the shape of a specific electrophysiological pattern, referred to as "epileptic spike", encountered during the epileptogenesis process in an in vivo model of temporal lobe epilepsy (mouse, kainate). Results show that the features of these transient events (duration and amplitude) change as a function of time as the brain evolves towards the chronic epileptic state characterized by the appearance of spontaneous seizures. Using a detailed computational model of the hippocampus (CA1 sub-field), an interpretation of observed modifications is provided, in relationship with possible alterations that take place in underlying neuronal circuits.
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Dunleavy M, Shinoda S, Schindler C, Ewart C, Dolan R, Gobbo OL, Kerskens CM, Henshall DC. Experimental neonatal status epilepticus and the development of temporal lobe epilepsy with unilateral hippocampal sclerosis. THE AMERICAN JOURNAL OF PATHOLOGY 2009; 176:330-42. [PMID: 19948825 DOI: 10.2353/ajpath.2010.090119] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hippocampal sclerosis is a common pathological finding in patients with temporal lobe epilepsy, including children, but a causal relationship to early-life seizures remains in question. Neonatal status epilepticus in animals can result in neuronal death within the hippocampus, although macroscopic features of hippocampal shrinkage are not evident at adulthood. Here, we examined electrophysiological and pathological consequences of focally evoked status epilepticus triggered by intra-amygdala microinjection of kainic acid in postnatal day 10 rat pups. Neonatal status epilepticus resulted in extensive neuronal death in the ipsilateral hippocampal CA1 and CA3 subfields and hilus, as assessed by DNA fragmentation and Fluoro-Jade B staining 72 hours later. The contralateral hippocampus was not significantly damaged. Histopathology at P55/P65 revealed unilateral hippocampal sclerosis (grade IV, modified Wyler/Watson scale) comprising >50% CA1 and CA3 neuron loss and astrogliosis. Additional features included hydrocephalus ex vacuo, modest dentate granule cell layer widening, and altered neuropeptide Y immunoreactivity indicative of synaptic rearrangement. Hippocampal atrophy was also evident on magnetic resonance imaging. Depth electrode recordings at adulthood detected spontaneous seizures that involved the ipsilateral hippocampus and amygdala. A significant positive correlation was found between hippocampal pathology grade and both frequency and duration of epileptic seizures at adulthood. The current study demonstrates that experimental neonatal status epilepticus can result in classical unilateral hippocampal sclerosis and temporal lobe epilepsy.
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Affiliation(s)
- Mark Dunleavy
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin 2, Ireland
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Allene C, Cossart R. Early NMDA receptor-driven waves of activity in the developing neocortex: physiological or pathological network oscillations? J Physiol 2009; 588:83-91. [PMID: 19917570 DOI: 10.1113/jphysiol.2009.178798] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Several patterns of coherent activity have been described in developing cortical structures, thus providing a general framework for network maturation. A detailed timely description of network patterns at circuit and cell levels is essential for the understanding of pathogenic processes occurring during brain development. Disturbances in the expression timetable of this pattern sequence are very likely to affect network maturation. This review focuses on the maturation of coherent activity patterns in developing neocortical structures. It emphasizes the intrinsic and synaptic cellular properties that are unique to the immature neocortex and, in particular, the critical role played by extracellular glutamate in controlling network excitability and triggering synchronous network waves of activity.
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Affiliation(s)
- Camille Allene
- INSERM u901, Institut de Neurobiologie de la Méditerranée, Unité 01 Parc Scientifique de Luminy, Boîte Postale 13, Marseille 13273, France
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Galic MA, Riazi K, Henderson AK, Tsutsui S, Pittman QJ. Viral-like brain inflammation during development causes increased seizure susceptibility in adult rats. Neurobiol Dis 2009; 36:343-51. [PMID: 19660546 DOI: 10.1016/j.nbd.2009.07.025] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2009] [Revised: 07/26/2009] [Accepted: 07/29/2009] [Indexed: 11/26/2022] Open
Abstract
Viral infections of the CNS and their accompanying inflammation can cause long-term neurological effects, including increased risk for seizures. To examine the effects of CNS inflammation, we infused polyinosinic:polycytidylic acid, intracerebroventricularly to mimic a viral CNS infection in 14 day-old rats. This caused fever and an increase in the pro-inflammatory cytokine, interleukin (IL)-1beta in the brain. As young adults, these animals were more susceptible to lithium-pilocarpine and pentylenetetrazol-induced seizures and showed memory deficits in fear conditioning. Whereas there was no alteration in adult hippocampal cytokine levels, we found a marked increase in NMDA (NR2A and C) and AMPA (GluR1) glutamate receptor subunit mRNA expression. The increase in seizure susceptibility, glutamate receptor subunits, and hippocampal IL-1beta levels were suppressed by neonatal systemic minocycline. Thus, a novel model of viral CNS inflammation reveals pathophysiological relationships between brain cytokines, glutamate receptors, behaviour and seizures, which can be attenuated by anti-inflammatory agents like minocycline.
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Affiliation(s)
- M A Galic
- Epilepsy and Brain Circuits Program, Hotchkiss Brain Institute, Department of Neuroscience, University of Calgary, Calgary, Alberta, Canada
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Hsu D, Chen W, Hsu M, Beggs JM. An open hypothesis: is epilepsy learned, and can it be unlearned? Epilepsy Behav 2008; 13:511-22. [PMID: 18573694 PMCID: PMC2611958 DOI: 10.1016/j.yebeh.2008.05.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2008] [Revised: 05/13/2008] [Accepted: 05/14/2008] [Indexed: 10/21/2022]
Abstract
Plasticity is central to the ability of a neural system to learn and also to its ability to develop spontaneous seizures. What is the connection between the two? Learning itself is known to be a destabilizing process at the algorithmic level. We have investigated necessary constraints on a spontaneously active Hebbian learning system and find that the ability to learn appears to confer an intrinsic vulnerability to epileptogenesis on that system. We hypothesize that epilepsy arises as an abnormal learned response of such a system to certain repeated provocations. This response is a network-level effect. If epilepsy really is a learned response, then it should be possible to reverse it, that is, to unlearn epilepsy. Unlearning epilepsy may then provide a new approach to its treatment.
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Affiliation(s)
- David Hsu
- Department of Neurology, University of Wisconsin, Madison, WI 53792, USA.
| | - Wei Chen
- Department of Physics, Indiana University, Bloomington IN
| | - Murielle Hsu
- Department of Neurology, University of Wisconsin, Madison WI
| | - John M. Beggs
- Department of Physics, Indiana University, Bloomington IN
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Wang L, Liu YH, Huang YG, Chen LW. Time-course of neuronal death in the mouse pilocarpine model of chronic epilepsy using Fluoro-Jade C staining. Brain Res 2008; 1241:157-67. [PMID: 18708038 DOI: 10.1016/j.brainres.2008.07.097] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2008] [Revised: 07/21/2008] [Accepted: 07/22/2008] [Indexed: 11/16/2022]
Abstract
Epilepsy is a serious neurological disorder in human beings and the long-term pathological events remain largely obscure. We are interested in elucidating long-term brain injury that may occur in the temporal lobe epilepsy, and time-course of neuronal death was examined in a mouse pilocarpine model of chronic epilepsy by Fluoro-Jade C (FJC) dye that can specifically stain the degenerative neurons in the central nervous system. The FJC stain combined with immunohistochemistry to neuronal nuclear specific protein revealed that pilocarpine-induced status epilepticus (SE) resulted in massive degenerative death of neuronal cells in brains with their dense distribution in the cerebral cortex and hippocampus. The FJC-positive degenerating neurons, most of them also expressed apoptosis signaling molecules such as caspase-9 and activated caspase-3, occurred at 4h, increased into peak levels at 12h-3d, and then gradually went down at 7d-14d after onset of SE. More interestingly, a large percentage (about 88%) of FJC-positive degenerative neurons were GABAergic as indicated with their immunoreactivity to glutamic acid decarboxylase-67, implying that inhibitory function of GABAergic neural system might by seriously damaged in brains subject to SE attack in this mouse pilocarpine model. Taken together with previous studies, time-course of degenerative neurons in the mouse pilocarpine model by Fluoro-Jade C staining further benefits understanding of long-term brain pathological changes and recurrent seizure mechanism, and may also result in finding the most suitable time-window in therapeutic manipulation of the chronic epilepsy in human beings.
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Affiliation(s)
- Lian Wang
- Institute of Neurosciences, The Fourth Military Medical University, Xi'an 710032, PR China
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