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Takeuchi H, Higurashi N, Toga Y. Prophylactic antiseizure medications for recurrent status epilepticus in nonsyndromic childhood epilepsy. Brain Dev 2024:S0387-7604(24)00043-3. [PMID: 38519270 DOI: 10.1016/j.braindev.2024.03.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/14/2024] [Accepted: 03/17/2024] [Indexed: 03/24/2024]
Abstract
PURPOSE The management of status epilepticus (SE) has mainly focused on the termination of ongoing SE episodes. However, long-term therapeutic strategies for the prevention of SE are lacking. This study aimed to investigate the effectiveness of prophylactic antiseizure medications (ASMs) for SEs in nonsyndromic childhood epilepsy. METHODS This retrospective study was conducted at Jikei University Hospital. Patients <18 years of age, diagnosed with epilepsy, and experiencing three or more SE episodes within 1 year between April 1, 2017, and October 1, 2021, were included. ASMs introduced for seizure types that developed into SE were evaluated. The effectiveness of ASMs was determined by using the "Rule of Three": An ASM was determined effective if patients were free of SE for a duration at least three times that of their longest SE interval in 12 months prior to intervention. RESULTS The investigation included a total of 32 ASMs administered to 13 patients. The longest interval between SE episodes before ASM administration was 28-257 d. The first SE interval after ASM administration was 12-797 d. Levetiracetam (LEV) and clobazam (CLB) showed effectiveness in 2/10 and 5/6 patients, respectively. Other ASMs were ineffective. The leading etiology of epilepsy was perinatal brain injury, identified in four patients, and CLB was effective in all of them. CONCLUSIONS The present study suggests that CLB and LEV may prolong the SE interval in some cases of nonsyndromic childhood epilepsy. CLB may be beneficial, particularly in patients with perinatal brain injury.
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Affiliation(s)
- Hirokazu Takeuchi
- Department of Pediatrics, Jikei University School of Medicine Tokyo, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan; Division of Neurology, Saitama Children's Medical Center, Saitama, Saitama Children's Medical Center, 1-2 Chuo-ku Saitama-shi, Saitama 330-8777, Japan.
| | - Norimichi Higurashi
- Department of Pediatrics, Jikei University School of Medicine Tokyo, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
| | - Yurika Toga
- Department of Pediatrics, Jikei University School of Medicine Tokyo, 3-25-8, Nishi-Shimbashi, Minato-ku, Tokyo, 105-8461, Japan.
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2
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Guo M, Wang J, Tang C, Deng J, Zhang J, Xiong Z, Liu S, Guan Y, Zhou J, Zhai F, Luan G, Li T. Effectiveness of vagus nerve stimulation therapy in refractory hypoxic-ischemic encephalopathy-induced epilepsy. Ther Adv Neurol Disord 2022; 15:17562864221144351. [PMID: 36578694 PMCID: PMC9791287 DOI: 10.1177/17562864221144351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2022] [Accepted: 11/23/2022] [Indexed: 12/24/2022] Open
Abstract
Background Epilepsy is one of the important long-term sequelae of neonatal hypoxic-ischemic encephalopathy (HIE) and is typically characterized by drug resistance and poor surgical outcomes. Vagus nerve stimulation (VNS) is a promising neuromodulation therapy for refractory epilepsy. Objectives The present study aimed to first evaluate the effectiveness of VNS in patients with refractory HIE-induced epilepsy and scrutinize potential clinical predictors. Methods We retrospectively collected the outcomes of VNS in all patients with refractory HIE-induced epilepsy and at least 2 years of follow-up. Subgroups were classified as responders and nonresponders according to the effectiveness of VNS (⩾50% or <50% reduction in seizure frequency). Preoperative data were analyzed to screen for potential predictors of VNS effectiveness. Results A total of 55 patients with refractory HIE-induced epilepsy who underwent VNS therapy were enrolled. Responders represented 56.4% of patients, and 12.7% of patients achieved seizure freedom at the last follow-up. In addition, the responder rate increased over time with rates of 23.6%, 38.2%, 50.9%, and 56.4% at the 3-, 6-, 12- and 24-month follow-ups, respectively. After multivariate analysis, neonatal seizure was identified as a negative predictor (OR: 4.640, 95% CI: 1.129-19.066), and a predominant seizure type of generalized onset was identified as a positive predictor (OR: 0.261, 95% CI: 0.078-0.873) of VNS effectiveness. Conclusion VNS therapy was effective in patients with refractory HIE-induced epilepsy and was well tolerated over a 2-year follow-up period. VNS therapy demonstrated better effectiveness in patients without neonatal seizures or with a predominant seizure type of generalized onset.
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Affiliation(s)
- Mengyi Guo
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurology, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Jing Wang
- Department of Neurology, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Chongyang Tang
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurosurgery, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Jiahui Deng
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Jing Zhang
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurology, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Zhonghua Xiong
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurology, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Siqi Liu
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurology, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Yuguang Guan
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurosurgery, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Jian Zhou
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurosurgery, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Feng Zhai
- Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China,Department of Neurosurgery, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Guoming Luan
- Department of Neurosurgery, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, XiangshanYikesong 50, Haidian District, Beijing 100093, China,Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Beijing Key Laboratory of Epilepsy Research, Sanbo Brain Hospital, Capital Medical University, Beijing, China
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3
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Nyman J, Mikkonen K, Metsäranta M, Toiviainen-Salo S, Vanhatalo S, Lauronen L, Nevalainen P. Poor aEEG background recovery after perinatal hypoxic ischemic encephalopathy predicts postneonatal epilepsy by age 4 years. Clin Neurophysiol 2022; 143:116-123. [DOI: 10.1016/j.clinph.2022.09.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2022] [Accepted: 09/02/2022] [Indexed: 11/26/2022]
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4
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Jablonski J, Hoffmann L, Blümcke I, Fejtová A, Uebe S, Ekici AB, Gnatkovsky V, Kobow K. Experimental Epileptogenesis in a Cell Culture Model of Primary Neurons from Rat Brain: A Temporal Multi-Scale Study. Cells 2021; 10:cells10113004. [PMID: 34831225 PMCID: PMC8616120 DOI: 10.3390/cells10113004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 12/24/2022] Open
Abstract
Understanding seizure development requires an integrated knowledge of different scales of organization of epileptic networks. We developed a model of “epilepsy-in-a-dish” based on dissociated primary neuronal cells from neonatal rat hippocampus. We demonstrate how a single application of glutamate stimulated neurons to generate spontaneous synchronous spiking activity with further progression into spontaneous seizure-like events after a distinct latency period. By computational analysis, we compared the observed neuronal activity in vitro with intracranial electroencephalography (EEG) data recorded from epilepsy patients and identified strong similarities, including a related sequence of events with defined onset, progression, and termination. Next, a link between the neurophysiological changes with network composition and cellular structure down to molecular changes was established. Temporal development of epileptiform network activity correlated with increased neurite outgrowth and altered branching, increased ratio of glutamatergic over GABAergic synapses, and loss of calbindin-positive interneurons, as well as genome-wide alterations in DNA methylation. Differentially methylated genes were engaged in various cellular activities related to cellular structure, intracellular signaling, and regulation of gene expression. Our data provide evidence that a single short-term excess of glutamate is sufficient to induce a cascade of events covering different scales from molecule- to network-level, all of which jointly contribute to seizure development.
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Affiliation(s)
- Janos Jablonski
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Lucas Hoffmann
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Ingmar Blümcke
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
| | - Anna Fejtová
- Department of Psychiatry and Psychotherapy, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany;
| | - Steffen Uebe
- NGS Core Unit, Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (S.U.); (A.B.E.)
| | - Arif B. Ekici
- NGS Core Unit, Institute of Human Genetics, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (S.U.); (A.B.E.)
| | - Vadym Gnatkovsky
- Department of Epileptology, University Hospital Bonn, 53127 Bonn, Germany;
| | - Katja Kobow
- Department of Neuropathology, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 91054 Erlangen, Germany; (J.J.); (L.H.); (I.B.)
- Correspondence: ; Tel.: +49-9131-8522859
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5
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Razaz N, Cnattingius S, Joseph KS. Association between Apgar scores of 7 to 9 and neonatal mortality and morbidity: population based cohort study of term infants in Sweden. BMJ 2019; 365:l1656. [PMID: 31064770 PMCID: PMC6503461 DOI: 10.1136/bmj.l1656] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/20/2019] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To investigate associations between Apgar scores of 7, 8, and 9 (versus 10) at 1, 5, and 10 minutes, and neonatal mortality and morbidity. DESIGN Population based cohort study. SETTING Sweden. PARTICIPANTS 1 551 436 non-malformed live singleton infants, born at term (≥37 weeks' gestation) between 1999 and 2016, with Apgar scores of ≥7 at 1, 5, and 10 minutes. EXPOSURES Infants with Apgar scores of 7, 8, and 9 at 1, 5, and 10 minutes were compared with those with an Apgar score of 10 at 1, 5, and 10 minutes, respectively. MAIN OUTCOME MEASURES Neonatal mortality and morbidity, including neonatal infections, asphyxia related complications, respiratory distress, and neonatal hypoglycaemia. Adjusted odds ratios (aOR), adjusted rate differences (aRD), and 95% confidence intervals were estimated. RESULTS Compared with infants with an Apgar score of 10, aORs for neonatal mortality, neonatal infections, asphyxia related complications, respiratory distress, and neonatal hypoglycaemia were higher among infants with lower Apgar scores, especially at 5 and 10 minutes. For example, the aORs for respiratory distress for an Apgar score of 9 versus 10 were 2.0 (95% confidence interval 1.9 to 2.1) at 1 minute, 5.2 (5.1 to 5.4) at 5 minutes, and 12.4 (12.0 to 12.9) at 10 minutes. Compared with an Apgar score of 10 at 10 minutes, the aRD for respiratory distress was 9.5% (95% confidence interval 9.2% to 9.9%) for an Apgar score of 9 at 10 minutes, and 41.9% (37.7% to 46.4%) for an Apgar score of 7 at 10 minutes. A reduction in Apgar score from 10 at 5 minutes to 9 at 10 minutes was also associated with higher odds of neonatal morbidity, compared with a stable Apgar score of 10 at 5 and 10 minutes. CONCLUSIONS In term non-malformed infants with Apgar scores within the normal range (7 to 10), risks of neonatal mortality and morbidity are higher among infants with lower Apgar score values, and also among those experiencing a reduction in score from 5 minutes to 10 minutes (compared with infants with stable Apgar scores of 10).
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Affiliation(s)
- Neda Razaz
- Division of Clinical Epidemiology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - Sven Cnattingius
- Division of Clinical Epidemiology, Department of Medicine Solna, Karolinska Institutet, Stockholm, Sweden
| | - K S Joseph
- Department of Obstetrics & Gynaecology, School of Population and Public Health, University of British Columbia and the Children's and Women's Hospital of British Columbia, Vancouver, BC, Canada
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6
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Xu Q, Chau V, Sanguansermsri C, Muir KE, Tam EWY, Miller SP, Wong DST, Chen H, Wong PKH, Zwicker JG, Poskitt KJ, Hill A, Roland EH. Pattern of Brain Injury Predicts Long-Term Epilepsy Following Neonatal Encephalopathy. J Child Neurol 2019; 34:199-209. [PMID: 30642234 DOI: 10.1177/0883073818822361] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To determine if patterns of hypoxic-ischemic brain injury on magnetic resonance imaging (MRI) in term newborns predict subsequent childhood epilepsy. METHODS This retrospective cohort study includes term newborns with encephalopathy (n = 181) born between 2004-2012 and admitted to British Columbia Children's Hospital. MRI was performed between 3 and 5 days of age. The predominant patterns of hypoxic-ischemic injury were classified as Normal, Watershed, Basal Nuclei, Total, and Focal-Multifocal. Lesions in hippocampus, motor and occipital cortex were noted. RESULTS Of 181 newborns, 166 (92%) survived the neonatal period, and 132 (80%) had follow-up with a median duration of 61 months (IQR: 28-95). Twenty-three children (17%) developed epilepsy. A higher proportion with Watershed, Basal Nuclei, or Total patterns developed epilepsy (P < .001). Injury to motor cortex, hippocampus, and occipital lobe (P < .01) were independent risk factors for epilepsy. In the adjusting logistic model, Watershed (odds ratio = 16.0, 95% CI [1.3, 197.2], P = .03) and Basal Nuclei injury (odds ratio = 19.4, 95% CI [1.9, 196.3], P = .01) remained independent risk factors. Therapeutic hypothermia did not alter these associations. Severity of brain injury and recurrent neonatal seizures are other clinical risk factors. SIGNIFICANCE In term newborns with hypoxic-ischemic encephalopathy, the predominant pattern of Watershed and Basal Nuclei injury are valuable predictors for development of epilepsy in later childhood.
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Affiliation(s)
- Qi Xu
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Vann Chau
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Pediatrics (Neurology), University of Toronto and the Hospital for Sick Children, Toronto, Ontario, Canada.,Neurosciences & Mental Health Research Institute, Toronto, Ontario, Canada
| | - Chinnuwat Sanguansermsri
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Katherine E Muir
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Emily W Y Tam
- Department of Pediatrics (Neurology), University of Toronto and the Hospital for Sick Children, Toronto, Ontario, Canada.,Neurosciences & Mental Health Research Institute, Toronto, Ontario, Canada
| | - Steven P Miller
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Pediatrics (Neurology), University of Toronto and the Hospital for Sick Children, Toronto, Ontario, Canada.,Neurosciences & Mental Health Research Institute, Toronto, Ontario, Canada
| | - Darren S T Wong
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Hao Chen
- Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Peter K H Wong
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Jill G Zwicker
- BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Pediatrics, Developmental Pediatrics, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.,Department of Occupational Science and Occupational Therapy, Vancouver, British Columbia, Canada.,Sunny Hill Health Centre for Children, Vancouver, British Columbia, Canada
| | - Kenneth J Poskitt
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada.,Department of Radiology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
| | - Alan Hill
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada.,BC Children's Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Elke H Roland
- Department of Pediatrics, Neurology, University of British Columbia and BC Children's Hospital, Vancouver, British Columbia, Canada
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Chen J, Liang H, Miao M, Su X, Yang F, Thomsen RW, Yuan W, Li J. In utero beta-2-adrenergic agonists exposure and risk of epilepsy: A Danish nationwide population-based cohort study. Pharmacoepidemiol Drug Saf 2018; 27:1200-1208. [PMID: 30256490 DOI: 10.1002/pds.4648] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 05/27/2018] [Accepted: 08/09/2018] [Indexed: 11/06/2022]
Abstract
PURPOSE To examine the association between maternal use of beta-2-adrenergic agonists (β2AAs) and the risk of epilepsy in offspring. METHODS A nationwide retrospective cohort study was performed based on Danish registries. Children of mothers who used β2AAs during pregnancy were allocated to the exposed group and other children to the unexposed group. The outcome was a diagnosis of epilepsy. Cox regression was performed to estimate the hazard ratios (HRs) of epilepsy after adjusting for parental and children factors. To evaluate confounding by indication, we extended the exposure time window from 2 years before pregnancy and stratified the analyses by maternal asthma, in particular analyses by trimesters. RESULTS The exposed children had a 1.24-fold risk of epilepsy (HR = 1.24, 95% confidence interval [CI]: 1.12, 1.38). Compared with no prenatal exposure from 2 years before pregnancy through delivery, the HR was 1.11 (95% CI: 1.01, 1.22) in children of mothers with β2AAs use only before pregnancy, 1.28 (95% CI: 1.09, 1.50) only during pregnancy, and 1.23 (95% CI: 1.07, 1.41) both before and during pregnancy. The increased risk was only observed in children of mothers with β2AAs use in the first (HR = 1.33, 95% CI: 1.01, 1.75) or second trimesters (HR = 1.35, 95% CI: 1.05, 1.74), but not the third trimester. CONCLUSIONS In utero exposure to β2AAs, particularly in the first or second trimesters, may be associated with an increased risk of epilepsy. It may partly be due to the indication of β2AAs use, but a direct effect of β2AAs cannot be ruled out.
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Affiliation(s)
- Jianping Chen
- Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, 200032, China.,Department of Fetal Medicine and Prenatal Diagnosis Center, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, 200040, Shanghai, China
| | - Hong Liang
- Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, 200032, China
| | - Maohua Miao
- Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, 200032, China
| | - Xiujuan Su
- Department of Women and Children's Health Care, Shanghai First Maternity and Infant Hospital, Tongji University School of Medicine, Shanghai, 200040, China
| | - Fen Yang
- Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, 200032, China
| | - Reimar W Thomsen
- Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Alle 43-45, DK-8200, Aarhus N, Denmark
| | - Wei Yuan
- Key Laboratory of Reproduction Regulation of NPFPC, SIPPR, IRD, Fudan University, Shanghai, 200032, China
| | - Jiong Li
- Department of Clinical Epidemiology, Aarhus University Hospital, Olof Palmes Alle 43-45, DK-8200, Aarhus N, Denmark.,Ministry of Education-Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
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8
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Lugli L, Balestri E, Berardi A, Guidotti I, Cavalleri F, Todeschini A, Pugliese M, Muttini Della Casa E, Lucaccioni L, Ferrari F. Brain cooling reduces the risk of postneonatal epilepsy in newborns affected by moderate to severe hypoxic-ischemic encephalopathy. Minerva Pediatr (Torino) 2018; 73:150-158. [PMID: 29968450 DOI: 10.23736/s2724-5276.18.05224-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Neonatal hypoxic-ischemic encephalopathy is still a significant cause of neonatal death and neurodevelopmental disabilities, such as cerebral palsy, mental delay, and epilepsy. After the introduction of therapeutic hypothermia, the prognosis of hypoxic-ischemic encephalopathy has improved, with reduction of death and disabilities. However, few studies evaluated whether hypothermia affects rate and severity of postneonatal epilepsy. We evaluated rates, characteristics and prognostic markers of postneonatal epilepsy in infants with moderate to severe hypoxic-ischemic encephalopathy treated or not with therapeutic hypothermia. METHODS We analyzed clinical data, EEG recordings, cerebral Magnetic Resonance Imaging (MRI) and outcome in 23 cooled and 26 non-cooled asphyxiated neonates (≥36 weeks' gestation), admitted from 2004 to 2012. RESULTS Among 49 neonates 11 (22%) had postneonatal epilepsy, of which 9 (18%) were non-cooled and 2 (4%) were cooled (P=0.05). Six of 11 infants (55%) had West syndrome, 4 (36%) had focal epilepsy and 1 (9%) had Lennox-Gastaut Syndrome. At multiple logistic regression analysis MRI pattern significantly correlated with postneonatal epilepsy (OR 0.19, 95% CI 0.04-0.88, P=0.03). Extensive lesions in basal ganglia and thalami plus cortical and white matter were associated with postneonatal epilepsy. CONCLUSIONS Only perinatal asphyxia with extensive lesions in basal ganglia and thalami plus cortical and white matter lesion conveys a high risk for early and severe postneonatal epilepsy. Moreover, therapeutic hypothermia is associated with a decrease of the risk of developing postneonatal epilepsy.
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Affiliation(s)
- Licia Lugli
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy -
| | - Eleonora Balestri
- Division of Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Reggio Emilia, Italy
| | - Alberto Berardi
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy
| | - Isotta Guidotti
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy
| | - Francesca Cavalleri
- Division of Neuroradiology, Department of Neuroscience, Nuovo Ospedale Civile S. Agostino Estense, Modena, Italy
| | - Alessandra Todeschini
- Division of Neuroradiology, Department of Neuroscience, Nuovo Ospedale Civile S. Agostino Estense, Modena, Italy
| | - Marisa Pugliese
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy
| | - Elisa Muttini Della Casa
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy
| | - Laura Lucaccioni
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy
| | - Fabrizio Ferrari
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Pediatrics, University Hospital, Modena, Italy
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9
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Dunn R, Queenan BN, Pak DTS, Forcelli PA. Divergent effects of levetiracetam and tiagabine against spontaneous seizures in adult rats following neonatal hypoxia. Epilepsy Res 2017; 140:1-7. [PMID: 29227795 DOI: 10.1016/j.eplepsyres.2017.12.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 10/09/2017] [Accepted: 12/02/2017] [Indexed: 01/03/2023]
Abstract
Animal models are valuable tools for screening novel therapies for patients who suffer from epilepsy. However, a wide array of models are necessary to cover the diversity of human epilepsies. In humans, neonatal hypoxia (or hypoxia-ischemia) is one of the most common causes of epilepsy early in life. Hypoxia-induced seizures (HS) during the neonatal period can also lead to spontaneous seizures in adulthood. This phenomenon, i.e., early-life hypoxia leading to adult epilepsy - is also seen in experimental models, including rats. However, it is not known which anti-seizure medications are most effective at managing adult epilepsy resulting from neonatal HS. Here, we examined the efficacy of three anti-seizure medications against spontaneous seizures in adult rats with a history of neonatal HS: (1) phenobarbital (PHB), the oldest epilepsy medicine still in use today; (2) levetiracetam (LEV); and (3) tiagabine (TGB). Both LEV and TGB are relatively new anticonvulsant drugs that are ineffective in traditional seizure models, but strikingly effective in other models. We found that PHB and LEV decreased seizures in adult rats with a history of HS, whereas TGB exacerbated seizures. These divergent drug effects indicate that the HS model may be useful for differentiating the clinical efficacy of putative epilepsy therapies.
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Affiliation(s)
- Raymond Dunn
- Department of Pharmacology and Physiology, United States
| | - Bridget N Queenan
- Department of Pharmacology and Physiology, United States; Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, United States; Neuroscience Research Institute, Department of Mechanical Engineering; Department of Physics, University sof California, Santa Barbara, Santa Barbara, CA, United States
| | - Daniel T S Pak
- Department of Pharmacology and Physiology, United States; Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, United States.
| | - Patrick A Forcelli
- Department of Pharmacology and Physiology, United States; Department of Neuroscience, United States; Interdisciplinary Program in Neuroscience, Georgetown University, Washington DC, United States.
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Razaz N, Tedroff K, Villamor E, Cnattingius S. Maternal Body Mass Index in Early Pregnancy and Risk of Epilepsy in Offspring. JAMA Neurol 2017; 74:668-676. [PMID: 28384785 DOI: 10.1001/jamaneurol.2016.6130] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Importance There is growing concern about the long-term neurologic effects of prenatal exposure to maternal overweight and obesity. The causes of epilepsy are poorly understood and, in more than 60% of the patients, no definitive cause can be determined. Objectives To investigate the association between early pregnancy body mass index (BMI) and the risk of childhood epilepsy and examine associations between obesity-related pregnancy and neonatal complications and risks of childhood epilepsy. Design, Setting, and Participants A population-based cohort study of 1 441 623 live single births at 22 or more completed gestational weeks in Sweden from January 1, 1997, to December 31, 2011, was conducted. The diagnosis of epilepsy as well as obesity-related pregnancy and neonatal complications were based on information from the Sweden Medical Birth Register and National Patient Register. Multivariate Cox proportional hazards regression models were used to estimate adjusted hazard ratios (HRs) and 95% CIs after adjusting for maternal age, country of origin, educational level, cohabitation with partner, height, smoking, maternal epilepsy, and year of delivery. Data analysis was conducted from June 1 to December 15, 2016. Main Outcomes and Measures Risk of childhood epilepsy. Results Of the 1 421 551 children born between January 1, 1997, and December 31, 2011, with covariate information available, 7592 (0.5%) were diagnosed with epilepsy through December 31, 2012. Of these 3530 (46.5%) were female. The overall incidence of epilepsy in children aged 28 days to 16 years was 6.79 per 10 000 child-years. Compared with offspring of normal-weight mothers (BMI 18.5 to <25.0), adjusted HRs of epilepsy by maternal BMI categories were as follows: overweight (BMI 25.0 to <30.0), 1.11 (95% CI, 1.04-1.17); obesity grade I (BMI 30.0 to <35.0), 1.20 (95% CI, 1.10-1.31); obesity grade II (BMI 35.0 to <40.0), 1.30 (95% CI, 1.12-1.50); and obesity grade III (BMI≥40.0), 1.82 (95% CI, 1.46-2.26). The rates of epilepsy were considerably increased for children with malformations of the nervous system (adjusted HR, 46.4; 95% CI, 42.2-51.0), hypoxic ischemic encephalopathy (adjusted HR, 23.6; 95% CI, 20.6-27.1), and neonatal convulsions (adjusted HR, 33.5; 95% CI, 30.1-37.4). The rates of epilepsy were doubled among children with neonatal hypoglycemia (adjusted HR, 2.10; 95% CI, 1.90-2.33) and respiratory distress syndrome (adjusted HR, 2.43; 2.21-2.66), and neonatal jaundice was associated with more than a 50% increased risk of epilepsy (adjusted HR, 1.47; 95% CI, 1.33-1.63). The elevated risk of epilepsy in children of overweight or obese mothers was not explained by obesity-related pregnancy or neonatal complications. Conclusions and Relevance The rates of childhood epilepsy increased with maternal overweight or obesity in a dose-response manner. Given that overweight and obesity are modifiable, prevention of obesity may be an important public health strategy to reduce the incidence of childhood epilepsy.
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Affiliation(s)
- Neda Razaz
- Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Kristina Tedroff
- Neuropediatric Unit, Department of Women's and Children's Health, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
| | - Eduardo Villamor
- Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden3Department of Epidemiology, School of Public Health, and Center for Human Growth and Development, University of Michigan, Ann Arbor
| | - Sven Cnattingius
- Clinical Epidemiology Unit, Department of Medicine Solna, Karolinska University Hospital, Karolinska Institutet, Stockholm, Sweden
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Sampath D, Valdez R, White AM, Raol YH. Anticonvulsant effect of flupirtine in an animal model of neonatal hypoxic-ischemic encephalopathy. Neuropharmacology 2017; 123:126-135. [PMID: 28587899 DOI: 10.1016/j.neuropharm.2017.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 05/07/2017] [Accepted: 06/02/2017] [Indexed: 12/20/2022]
Abstract
Research studies suggest that neonatal seizures, which are most commonly associated with hypoxic-ischemic injury, may contribute to brain injury and adverse neurologic outcome. Unfortunately, neonatal seizures are often resistant to treatment with current anticonvulsants. In the present study, we evaluated the efficacy of flupirtine, administered at clinically relevant time-points, for the treatment of neonatal seizures in an animal model of hypoxic-ischemic injury that closely replicates features of the human syndrome. We also compared the efficacy of flupirtine to that of phenobarbital, the current first-line drug for neonatal seizures. Flupirtine is a KCNQ potassium channel opener. KCNQ channels play an important role in controlling brain excitability during early development. In this study, hypoxic-ischemic injury was induced in neonatal rats, and synchronized video-EEG records were acquired at various time-points during the experiment to identify seizures. The results revealed that flupirtine, administered either 5 min after the first electroclinical seizure, or following completion of 2 h of hypoxia, i.e., during the immediate reperfusion period, reduced the number of rats with electroclinical seizures, and also the frequency and total duration of electroclinical seizures. Further, daily dosing of flupirtine decreased the seizure burden over 3 days following HI-induction, and modified the natural evolution of acute seizures. Moreover, compared to a therapeutic dose of phenobarbital, which was modestly effective against electroclinical seizures, flupirtine showed greater efficacy. Our results indicate that flupirtine is an extremely effective treatment for neonatal seizures in rats and provide evidence for a trial of this medication in newborn humans.
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Affiliation(s)
- Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Robert Valdez
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Andrew M White
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA.
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Sharma AK, Reams RY, Jordan WH, Miller MA, Thacker HL, Snyder PW. Mesial Temporal Lobe Epilepsy: Pathogenesis, Induced Rodent Models and Lesions. Toxicol Pathol 2016; 35:984-99. [PMID: 18098044 DOI: 10.1080/01926230701748305] [Citation(s) in RCA: 195] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Mesial temporal lobe epilepsy (MTLE), the most common epilepsy in adults, is generally intractable and is suspected to be the result of recurrent excitation or inhibition circuitry. Recurrent excitation and the development of seizures have been associated with aberrant mossy fiber sprouting in the hippocampus. Of the animal models developed to investigate the pathogenesis of MTLE, post-status epilepticus models have received the greatest acceptance because they are characterized by a latency period, the development of spontaneous motor seizures, and a spectrum of lesions like those of MTLE. Among post-status epilepticus models, induction of systemic kainic acid or pilocarpine-induced epilepsy is less labor-intensive than electrical-stimulation models and these models mirror the clinicopathologic features of MTLE more closely than do kindling, tetanus toxin, hyperthermia, post-traumatic, and perinatal hypoxia/ischemia models. Unfortunately, spontaneous motor seizures do not develop in kindling or adult hyperthermia models and are not a consistent finding in tetanus toxin-induced or perinatal hypoxia/ischemia models. This review presents the mechanistic hypotheses for seizure induction, means of model induction, and associated pathology, especially as compared to MTLE patients. Animal models are valuable tools not only to study the pathogenesis of MTLE, but also to evaluate potential antiepileptogenic drugs.
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Affiliation(s)
- Alok K. Sharma
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
- Department of Pathology, Covance Laboratories Inc., Madison, WI, 53704, USA
| | - Rachel Y. Reams
- Department of Pathology, Lilly Research Laboratories, Division of Eli Lilly and Co., Greenfield, IN, 46140, USA
| | - William H. Jordan
- Department of Pathology, Lilly Research Laboratories, Division of Eli Lilly and Co., Greenfield, IN, 46140, USA
| | - Margaret A. Miller
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - H. Leon Thacker
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
| | - Paul W. Snyder
- Department of Comparative Pathobiology, Purdue University, West Lafayette, IN 47907, USA
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13
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Heljic S, Uzicanin S, Catibusic F, Zubcevic S. Predictors of Mortality in Neonates with Seizures; a Prospective Cohort Study. Med Arch 2016; 70:182-5. [PMID: 27594742 PMCID: PMC5010067 DOI: 10.5455/medarh.2016.70.182-185] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 04/15/2016] [Indexed: 02/03/2023] Open
Abstract
OBJECTIVE The aim of this study was to analyze prognostic indicators for mortality in neonates with seizures in a level III Neonatal Intensive Care Unit (NICU). PATIENTS AND METHODS A cohort of 100 neonates with clinically manifested seizures hospitalized in the NICU during 4 years period was prospectively monitored for the first year of life. The cohort consisted of 33 preterm and 67 full-term babies with 60 male and 40 female infants. RESULTS The mortality rate in the first year of life of infants with seizures in the neonatal period was 23%. The most common cause of seizures was birth asphyxia for full-term infants and intra-periventricular hemorrhage for preterm infants. Death was more common in pre-term than term infants (p <0,005). Simple regression demonstrated statistically significant associations between death in the first year of life and a cluster of highly associated variables: resuscitation (p<0, 01), mechanical ventilation (p<0,01) and asphyxia (p<0,05). This cluster of variables significantly correlates with: gestational age (p<0, 05), birth weight (p<0, 05) and intracranial hemorrhage (p<0, 05). CONCLUSION In this cohort of neonates with seizures asphyxia requiring neonatal resuscitation was the primary risk factor for death.
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Affiliation(s)
- Suada Heljic
- Neonatal Intensive Care Unit, Pediatric Clinic, UCC Sarajevo, Bosnia and Herzegovina
| | - Sajra Uzicanin
- Neonatal Intensive Care Unit, Pediatric Clinic, UCC Sarajevo, Bosnia and Herzegovina
| | - Feriha Catibusic
- Child Neurology Department, Pediatric Clinic, UCC Sarajevo, Bosnia and Herzegovina
| | - Smail Zubcevic
- Child Neurology Department, Pediatric Clinic, UCC Sarajevo, Bosnia and Herzegovina
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Sun H, Juul HM, Jensen FE. Models of hypoxia and ischemia-induced seizures. J Neurosci Methods 2015; 260:252-60. [PMID: 26434705 DOI: 10.1016/j.jneumeth.2015.09.023] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 09/22/2015] [Indexed: 01/19/2023]
Abstract
Despite greater understanding and improved management, seizures continue to be a major problem in childhood. Neonatal seizures are often refractory to conventional antiepileptic drugs, and can result in later life epilepsy and cognitive deficits, conditions for which there are no specific treatments. Hypoxic and/or ischemic encephalopathy (HIE) is the most common cause for neonatal seizures, and accounts for more than two-thirds of neonatal seizure cases. A better understanding of the cellular and molecular mechanisms is essential for identifying new therapeutic strategies that control the neonatal seizures and its cognitive consequences. This heavily relies on animal models that play a critical role in discovering novel mechanisms underlying both epileptogenesis and associated cognitive impairments. To date, a number of animal models have provided a tremendous amount of information regarding the pathophysiology of HIE-induced neonatal seizures. This review provides an overview on the most important features of the main animal models of HIE-induced seizures. In particular, we focus on the methodology of seizure induction and the characterizations of post-HIE injury consequences. These aspects of HIE-induced seizure models are discussed in the light of the suitability of these models in studying human HIE-induced seizures.
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Affiliation(s)
- Hongyu Sun
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Halvor M Juul
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Frances E Jensen
- Department of Neurology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States.
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Sampath D, Shmueli D, White AM, Raol YH. Flupirtine effectively prevents development of acute neonatal seizures in an animal model of global hypoxia. Neurosci Lett 2015; 607:46-51. [PMID: 26365409 DOI: 10.1016/j.neulet.2015.09.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 08/18/2015] [Accepted: 09/07/2015] [Indexed: 12/16/2022]
Abstract
Current first-line drugs for the treatment of neonatal seizures have limited efficacy and are associated with side effects. Uncontrolled seizures may exacerbate brain injury and contribute to later-life neurological disability. Therefore, it is critical to develop a treatment for neonatal seizures that is effective and safe. In early-life, when the γ-aminobutyric acid (GABA) inhibitory system is not fully developed, potassium channels play an important role in controlling excitability. An earlier study demonstrated that flupirtine, a KCNQ potassium channel opener, is more efficacious than diazepam and phenobarbital for the treatment of chemoconvulsant-induced neonatal seizures. In newborns, seizures are most commonly associated with hypoxic-ischemic encephalopathy (HIE). Thus, in the present study, we examined the efficacy of flupirtine to treat neonatal seizures in an animal model of global hypoxia. Our results showed that flupirtine dose dependently blocks the occurrence of behavioral seizures in pups during hypoxia. Additionally, flupirtine inhibits the development of hypoxia-induced clinical seizures and associated epileptiform discharges, as well as purely electrographic (subclinical) seizures. These results suggest that flupirtine is an effective anti-seizure drug, and that further studies should be conducted to determine the time window within which it's administration can effectively treat neonatal seizures.
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Affiliation(s)
- Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, School of Medicine, Aurora, CO 80045, United States
| | - Doron Shmueli
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, School of Medicine, Aurora, CO 80045, United States
| | - Andrew M White
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, School of Medicine, Aurora, CO 80045, United States
| | - Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado, School of Medicine, Aurora, CO 80045, United States.
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Sampath D, White AM, Raol YH. Characterization of neonatal seizures in an animal model of hypoxic-ischemic encephalopathy. Epilepsia 2014; 55:985-93. [PMID: 24836645 DOI: 10.1111/epi.12646] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE In this study, we use time-locked video and electroencephalography (EEG) recordings to characterize acute seizures and EEG abnormalities in an animal model that replicates many salient features of human neonatal hypoxic-ischemic encephalopathy (HIE) including the brain injury pattern and long-term neurologic outcome. METHODS Hypoxia-ischemia (HI) was induced in 7-day-old rats by ligating the right carotid artery and exposing the pups to hypoxia for 2 h (Rice-Vannucci method). To identify seizures and abnormal EEG activity, pups were monitored by video-EEG during hypoxia and at various time points after HI. Occurrence of electroclinical seizures, purely electrographic seizures and other abnormal discharges on EEG, was quantified manually. A power spectrum analysis was done to evaluate the effects of HI on EEG spectra in the 1-50 Hz frequency band. RESULTS During hypoxia, all pups exhibit short duration, but frequent electroclinical seizures. Almost all pups continue to have seizures in the immediate period following termination of hypoxia. In more than half of the HI rats, seizures persisted for 24 h; for some of them, the seizures continued for >48 h. Seizures were not observed in any rats at 72 h after HI induction. A significant reduction in background EEG voltage in the cortex ipsilateral to the ligated carotid artery occurred in rats subjected to HI. In addition, purely electrographic seizures, spikes, sharp waves, and brief runs of epileptiform discharges (BREDs) were also observed in these rats. SIGNIFICANCE HI induction in P7 rats using the Rice-Vannucci method resulted in the development of seizures and EEG abnormalities similar to that seen in human neonates with HIE. Therefore, we conclude that this is a valid model to test the efficacy of novel interventions to treat neonatal seizures.
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Affiliation(s)
- Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, Colorado, U.S.A
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Chevallier M, Ego A, Cans C, Debillon T. Adherence to hypothermia guidelines: a French multicenter study of fullterm neonates. PLoS One 2013; 8:e83742. [PMID: 24391817 PMCID: PMC3877096 DOI: 10.1371/journal.pone.0083742] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 11/07/2013] [Indexed: 11/18/2022] Open
Abstract
AIM The objective of this study was to describe the French practice of hypothermia treatment (HT) in full-term newborns with hypoxic-ischemic encephalopathy (HIE) and to analyze the deviations from the guidelines of the French Society of Neonatology. MATERIALS AND METHODS From May 2010 to March 2012 we recorded all cases of HIE treated by HT in a French national database. The population was divided into three groups, "optimal HT" (OHT), "late HT" (LHT) and "non-indicated" HT (NIHT), according to the guidelines. RESULTS Of the 311 newborns registered in the database and having HT, 65% were classified in the OHT group, 22% and 13% in the LHT and NIHT groups respectively. The severity of asphyxia and HIE were comparable between newborns with OHT and LHT, apart from EEG. HT was initiated at a mean time of 12 hours of life in the LHT group. An acute obstetrical event was more likely to be identified among newborns with LHT (46%), compared to OHT (34%) and NIHT (22%). There was a gradation in the rate of complications from the NIHT group (29%) to the LHT (38%) group and the OHT group (52%). Despite an insignificant difference in the rates of death or abnormal neurological examination at discharge, nearly 60% of newborns in the OHT group had an MRI showing abnormalities, compared to 44% and 49% in the LHT and NIHT groups respectively. CONCLUSION The conduct of the HT for HIE newborns is not consistent with French guidelines for 35% of newborns, 22% being explained by an excessive delay in the start of HT, 13% by the lack of adherence to the clinical indications. This first report illustrates the difficulties in implementing guidelines for HT and should argue for an optimization of perinatal care for HIE.
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Affiliation(s)
- Marie Chevallier
- Neonatology and Pediatric Intensive Care Unit, Grenoble University Hospital, Grenoble, France
| | - Anne Ego
- Clinical Research Center (CICO3), Grenoble University Hospital, Grenoble, France
| | - Christine Cans
- THEMAS (Techniques pour l'évaluation et la modélisation des actions de santé), Joseph Fourier University-Grenoble1, Grenoble, France
| | - Thierry Debillon
- Neonatology and Pediatric Intensive Care Unit, Grenoble University Hospital, Grenoble, France
- * E-mail:
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Leonard AS, Hyder SN, Kolls BJ, Arehart E, Ng KCW, Veerapandiyan A, Mikati MA. Seizure predisposition after perinatal hypoxia: effects of subsequent age and of an epilepsy predisposing gene mutation. Epilepsia 2013; 54:1789-800. [PMID: 24032507 DOI: 10.1111/epi.12347] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/23/2013] [Indexed: 02/06/2023]
Abstract
PURPOSE There is a gap in our knowledge of the factors that modulate the predisposition to seizures following perinatal hypoxia. Herein, we investigate in a mouse model the effects of two distinct factors: developmental stage after the occurrence of the perinatal insult, and the presence of a seizure predisposing mutation. METHODS Effects of age: P6 (postnatal day 6) mouse pups were subjected to acute hypoxia down to 4% O2 over the course of 45 min. Seizure susceptibilities to flurothyl-induced seizures (single exposures) and to flurothyl kindling were determined at specific subsequent ages. Effects of mutation: Heterozygote mice, with deletion of one copy of the Kcn1a gene, subjected to P6 hypoxia were compared as adults to wild-type mice with respect to susceptibility to a single exposure to flurothyl and to the occurrence of spontaneous seizures as detected by hippocampal electroencephalography (EEG) and video recordings. KEY FINDINGS Effects of age: As compared to controls, wild-type mice exposed to P6 hypoxia had a shortened seizure latency in response to a single flurothyl exposure at P50, but not at P7 or P28 (p < 0.04). In addition, perinatal hypoxia at P6 enhanced the rate of development of flurothyl kindling performed at P28-38 (p < 0.03), but not at P7-17. Effects of mutation: Kcn1a heterozygous mice subjected to P6 hypoxia exhibited increased susceptibility to flurothyl-induced seizures at P50 as compared to Normoxia heterozygote littermates, and to wild-type Hypoxia and Normoxia mice. In addition, heterozygotes exposed to P6 hypoxia were the only group in which spontaneous seizures were detected during the period of long-term monitoring (p < 0.027 in all comparisons). SIGNIFICANCE Our data establish a mouse model of mild perinatal hypoxia in which we document the following: (1) the emergence, after a latent period, of increased susceptibility to flurothyl-induced seizures, and to flurothyl induced kindling; and (2) an additive effect of a gene mutation to the seizure predisposing consequences of perinatal hypoxia, thereby demonstrating that a modifier (or susceptibility) gene can exacerbate the long-term consequences of hypoxic injury.
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Affiliation(s)
- A Soren Leonard
- Division of Pediatric Neurology, Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, U.S.A
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Sanchez RM, Ribak CE, Shapiro LA. Synaptic connections of hilar basal dendrites of dentate granule cells in a neonatal hypoxia model of epilepsy. Epilepsia 2012; 53 Suppl 1:98-108. [PMID: 22612814 DOI: 10.1111/j.1528-1167.2012.03481.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Numerous animal models of epileptogenesis demonstrate neuroplastic changes in the hippocampus. These changes occur not only for the mature neurons and glia, but also for the newly generated granule cells in the dentate gyrus. One of these changes, the sprouting of mossy fiber axons, is derived predominantly from newborn granule cells in adult rats with pilocarpine-induced temporal lobe epilepsy. Newborn granule cells also mainly contribute to another neuroplastic change, hilar basal dendrites (HBDs), which are synaptically targeted by mossy fibers in the hilus. Both sprouted mossy fibers and HBDs contribute to recurrent excitatory circuitry that is hypothesized to be involved in increased seizure susceptibility and the development of spontaneous recurrent seizures (SRS) that occur following the initial pilocarpine-induced status epilepticus. Considering the putative role of these neuroplastic changes in epileptogenesis, a critical question is whether similar anatomic phenomena occur after epileptogenic insults to the immature brain, where the proportion of recently born granule cells is higher due to ongoing maturation. The current study aimed to determine if such neuroplastic changes could be observed in a standardized model of neonatal seizure-inducing hypoxia that results in development of SRS. We used immunoelectron microscopy for the immature neuronal marker doublecortin to label newborn neurons and their HBDs following neonatal hypoxia. Our goal was to determine whether synapses form on HBDs from neurons born after neonatal hypoxia. Our results show a robust synapse formation on HBDs from animals that experienced neonatal hypoxia, regardless of whether the animals experienced tonic-clonic seizures during the hypoxic event. In both cases, the axon terminals that synapse onto HBDs were identified as mossy fiber terminals, based on the appearance of dense core vesicles. No such synapses were observed on HBDs from newborn granule cells obtained from sham animals analyzed at the same time points. This aberrant circuit formation may provide an anatomic substrate for increased seizure susceptibility and the development of epilepsy.
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Affiliation(s)
- Russell M Sanchez
- Department of Surgery and Neuroscience and Experimental Therapeutics, College of Medicine, Texas A&M Health Science Center, 1901 S. 1st Street, Temple, TX 76504, U.S.A
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Xiang K, Earl D, Dwyer T, Behrle BL, Tietz EI, Greenfield LJ. Hypoxia enhances high-voltage-activated calcium currents in rat primary cortical neurons via calcineurin. Epilepsy Res 2012; 99:293-305. [PMID: 22245138 PMCID: PMC3341530 DOI: 10.1016/j.eplepsyres.2011.12.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Revised: 12/04/2011] [Accepted: 12/18/2011] [Indexed: 01/09/2023]
Abstract
Hypoxia regulates neuronal ion channels, sometimes resulting in seizures. We evaluated the effects of brief sustained hypoxia (1% O(2), 4h) on voltage-gated calcium channels (VGCCs) in cultured rat primary cortical neurons. High-voltage activated (HVA) Ca(2+) currents were acquired immediately after hypoxic exposure or after 48h recovery in 95% air/5% CO(2). Maximal Ca(2+) current density increased 1.5-fold immediately after hypoxia, but reverted to baseline after 48h normoxia. This enhancement was primarily due to an increase in L-type VGCC activity, since nimodipine-insensitive residual Ca(2+) currents were unchanged. The half-maximal potentials of activation and steady-state inactivation were unchanged. The calcineurin inhibitors FK-506 (in the recording pipette) or cyclosporine A (during hypoxia) prevented the post-hypoxic increase in HVA Ca(2+) currents, while rapamycin and okadaic acid did not. L-type VGCCs were the source of Ca(2+) for calcineurin activation, as nimodipine during hypoxia prevented post-hypoxic enhancement. Hypoxia transiently potentiated L-type VGCC currents via calcineurin, suggesting a positive feedback loop to amplify neuronal calcium signaling that may contribute to seizure generation.
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Affiliation(s)
- Kun Xiang
- Department of Neurology, University of Toledo College of Medicine, Toledo, OH, USA
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Burton KJ, Rogathe J, Whittaker R, Mankad K, Hunter E, Burton MJ, Todd J, Neville BGR, Walker R, Newton CRJC. Epilepsy in Tanzanian children: association with perinatal events and other risk factors. Epilepsia 2012; 53:752-60. [PMID: 22308971 PMCID: PMC3467761 DOI: 10.1111/j.1528-1167.2011.03395.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Purpose To define the prevalence and risk factors for epilepsy in children in a rural district of Tanzania by conducting a community-based case–control study. Methods Children aged 6–14 years with active epilepsy (at least two unprovoked seizures in the last 5 years) were identified in a cross-sectional survey in Tanzania. Cases were compared with age-matched controls. Key Findings Overall 112 children with epilepsy (CWE) were identified; the unadjusted prevalence of epilepsy was 2.91 per 1,000 (95% confidence interval [95% CI] 2.4–3.5). The main seizure types were focal motor with secondary generalization in 73 (65.2%) of 112 and generalized convulsive seizures in 19 (16.9%) of 112. Adverse perinatal events were present in 16 (14%) of 112 cases but in no controls. In multivariate analysis, epilepsy was associated with number of parents who were resident at home (odds ratio [OR] 6.2 for none vs. both resident, 95% CI 1.5–25.5), history of adverse perinatal events (OR 14.9, 95% CI 1.4–151.3), family history of afebrile seizures (OR 5.7, 95% CI 1.0–27.5), and poor scholastic attainment (OR 8.6, 95% CI 4.0–18.4). Electroencephalography (EEG) and computed tomography (CT) scans were abnormal in 44 (44%) of 101 and 26 (29%) of 90 cases, respectively. Overall, 98 (88%) of 112 cases had focal features on assessment. Significance In this study from sub-Saharan Africa, CWE predominantly had focal features that support the suggestion that most epilepsy in this region has a symptomatic etiology. Adverse perinatal events were strongly associated with epilepsy. Genetic and social factors may also be important. Epilepsy may be preventable in a significant proportion of children with better antenatal and perinatal care.
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Experimental models of seizures and epilepsies. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2012; 105:57-82. [PMID: 22137429 DOI: 10.1016/b978-0-12-394596-9.00003-2] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Epilepsy is one of the most common neurological conditions that affect people of all ages. Epilepsy is characterized by occurrence of spontaneous recurrent seizures. Currently available drugs are ineffective in controlling seizures in approximately one-third of patients with epilepsy. Moreover, these drugs are associated with adverse effects, and none of them are effective in preventing development of epilepsy following an insult or injury. To develop an effective therapeutic strategy that can interfere with the process of development of epilepsy (epileptogenesis), it is crucial to study the changes that occur in the brain after an injury and before epilepsy develops. It is not possible to determine these changes in human tissue for obvious ethical reasons. Over the years, experimental models of epilepsies have contributed immensely in improving our understanding of mechanism of epileptogenesis as well as of seizure generation. There are many models that replicate at least some of the characteristics of human epilepsy. Each model has its advantages and disadvantages, and the investigator should be aware of this before selecting a specific model for his/her studies. Availability of a good animal model is a key to the development of an effective treatment. Unfortunately, there are many epilepsy syndromes, specifically pediatric, which still lack a valid animal model. It is vital that more research is done to develop animal models for such syndromes.
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Striatal GABA Receptor Alterations in Hypoxic Neonatal Rats: Role of Glucose, Oxygen and Epinephrine Treatment. Neurochem Res 2011; 37:629-38. [DOI: 10.1007/s11064-011-0654-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Revised: 11/03/2011] [Accepted: 11/08/2011] [Indexed: 12/18/2022]
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Dudek FE, Staley KJ. Seizure probability in animal models of acquired epilepsy: a perspective on the concept of the preictal state. Epilepsy Res 2011; 97:324-31. [PMID: 22094446 DOI: 10.1016/j.eplepsyres.2011.10.017] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2011] [Accepted: 10/17/2011] [Indexed: 10/15/2022]
Abstract
The concept of a preictal state is based on the belief that it may be possible to predict seizures before they occur. The preictal state is viewed as a time period when a seizure is practically inevitable, or at least a period of greatly increased seizure probability. Changes in seizure frequency may provide insight into how seizure probability increases after brain injury. Here, time-dependent changes in the frequency of spontaneous recurrent seizures after brain injury are summarized from published, nearly continuous, electrographic (EEG) recordings of kainate-treated rats and neonatal rats subjected to hypoxia-ischemia. For these animal models, seizure frequency - and thus seizure probability - was a sigmoid function of time after the brain injury. This observation differs from the traditional view, where the development of epilepsy after brain injury is a step-function of time, and the latent period is the time between a brain injury and the first spontaneous seizure. Based on backward extrapolation of the plots of seizure frequency versus time, these data suggest that seizure probability increases continuously during the latent period. Also, spontaneous recurrent seizures frequently occurred in clusters, suggesting that the intra-cluster seizure intervals are periods of high seizure probability. Thus, seizure probability progressively increases as a function of time after an epileptogenic brain injury, and is particularly high between seizures within a cluster, as compared to the time between clusters. These data suggest that the detectors of the preictal state need to be accurate (and tested) over a very wide range of seizure probabilities, and that studies on the physiological events that occur during seizure clusters may provide insight on the properties of the preictal state.
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Affiliation(s)
- F Edward Dudek
- Department of Physiology, University of Utah School of Medicine, 420 Chipeta Way, Suite 1700, Salt Lake City, UT 84108, United States.
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Glass HC, Hong KJ, Rogers EE, Jeremy RJ, Bonifacio SL, Sullivan JE, Barkovich AJ, Ferriero DM. Risk factors for epilepsy in children with neonatal encephalopathy. Pediatr Res 2011; 70:535-40. [PMID: 21796017 PMCID: PMC3189270 DOI: 10.1203/pdr.0b013e31822f24c7] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
We examined neonatal predictors of epilepsy in term newborns with neonatal encephalopathy (NE) by studying children enrolled in a longitudinal, single center cohort study. Clinical data were obtained through chart review, and MRI was performed in the neonatal period. We administered a seizure questionnaire to parents of children aged ≥ 12 mo (range, 12 mo to 16.5 y) to determine the outcome of epilepsy. The association between clinical predictors and time to onset of epilepsy was assessed using Cox proportional hazards regression. Thirteen of 129 children developed epilepsy: all had neonatal seizures and brain injury on neonatal MRI. Of the newborns with neonatal seizures, 25% (15.8/1000 person-years) developed epilepsy, with the highest hazard ratios (HRs) in the newborns with status epilepticus (HR, 35.8; 95% CI, 6.5-196.5). Children with severe or near-total brain injury were more likely to develop epilepsy compared with those with only mild or moderate injury (HR, 5.5; 95% CI, 1.8-16.8). In a multivariable analysis adjusting for degree of encephalopathy and severe/near-total brain injury, status epilepticus was independently associated with epilepsy. These data add to information regarding epilepsy pathogenesis and further aid clinicians to counsel parents regarding the likelihood that a newborn with NE will develop epilepsy.
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Affiliation(s)
- Hannah C Glass
- Department of Neurology, University of California at San Francisco, San Francisco, California 94143, USA.
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Stereotyped fetal brain disorganization is induced by hypoxia and requires lysophosphatidic acid receptor 1 (LPA1) signaling. Proc Natl Acad Sci U S A 2011; 108:15444-9. [PMID: 21878565 DOI: 10.1073/pnas.1106129108] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Fetal hypoxia is a common risk factor that has been associated with a range of CNS disorders including epilepsy, schizophrenia, and autism. Cellular and molecular mechanisms through which hypoxia may damage the developing brain are incompletely understood but are likely to involve disruption of the laminar organization of the cerebral cortex. Lysophosphatidic acid (LPA) is a bioactive lipid capable of cortical influences via one or more of six cognate G protein-coupled receptors, LPA(1-6), several of which are enriched in fetal neural progenitor cells (NPCs). Here we report that fetal hypoxia induces cortical disruption via increased LPA(1) signaling involving stereotyped effects on NPCs: N-cadherin disruption, displacement of mitotic NPCs, and impaired neuronal migration, as assessed both ex vivo and in vivo. Importantly, genetic removal or pharmacological inhibition of LPA(1) prevented the occurrence of these hypoxia-induced phenomena. Hypoxia resulted in overactivation of LPA(1) through selective inhibition of G protein-coupled receptor kinase 2 expression and activation of downstream pathways including G(αi) and Ras-related C3 botulinum toxin substrate 1. These data identify stereotyped and selective hypoxia-induced cerebral cortical disruption requiring LPA(1) signaling, inhibition of which can reduce or prevent disease-associated sequelae, and may take us closer to therapeutic treatment of fetal hypoxia-induced CNS disorders and possibly other forms of hypoxic injury.
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Downregulation of hippocampal GABA after hypoxia-induced seizures in neonatal rats. Neurochem Res 2011; 36:2409-16. [PMID: 21833845 DOI: 10.1007/s11064-011-0565-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2010] [Revised: 05/28/2011] [Accepted: 07/27/2011] [Indexed: 02/04/2023]
Abstract
This study aims to determine the expression of Gamma-aminobutyric acid (GABA) following hypoxia in neonatal rats and explore how it may increase susceptibility to epilepsy later in life. A modified model of neonatal hypoxia-induced epileptic susceptibility was simulated by 17 min of hypoxia (5% O(2) and 95% N(2)) in postnatal day (P) 10 rats. Hippocampal glutamate decarboxylase (GAD) and parvalbumin (PV) during the development with or without hypoxia were examined using immunohistochemistry. No detectable neuronal loss was observed in the hippocampus either immediately or 14 days after hypoxia. During the development GAD- and PV-immunoreactivity increased substantially during P 11-13 and reached mature expression in the control rats, and decreased significantly at different time points except for a transient increase during P 11-13 in the hypoxic groups. Our study indicates that downregulation of hippocampal GABA after hypoxia-induced seizures in neonatal rats may contribute to higher epileptic susceptibility in later life.
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Alterations in Serotonin Receptors and Transporter Immunoreactivities in the Hippocampus in the Rat Unilateral Hypoxic-induced Epilepsy Model. Cell Mol Neurobiol 2011; 31:1245-55. [DOI: 10.1007/s10571-011-9726-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2011] [Accepted: 06/06/2011] [Indexed: 11/26/2022]
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Dudek FE, Staley KJ. The time course of acquired epilepsy: implications for therapeutic intervention to suppress epileptogenesis. Neurosci Lett 2011; 497:240-6. [PMID: 21458536 DOI: 10.1016/j.neulet.2011.03.071] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2011] [Accepted: 03/23/2011] [Indexed: 01/27/2023]
Abstract
Relatively little is known about the time course of the development of spontaneous recurrent seizures (i.e., epileptogenesis) after brain injury in human patients, or even in animal models. This time course is determined, at least in part, by the underlying molecular and cellular mechanisms responsible for acquired epilepsy. An understanding of the critical mechanistic features of acquired epilepsy will be useful, if not essential, for developing strategies to block or suppress epileptogenesis. Here, data on the time course of the development of spontaneous recurrent seizures are summarized from experiments using nearly continuous electrographic (EEG) recordings in (1) kainate-treated rats, which are a model of temporal lobe epilepsy, and (2) rats subjected to unilateral carotid occlusion with superimposed hypoxia at postnatal day 7, which is a model of perinatal stroke. Although the classical view of the development of epileptogenesis is a step-function of time after the brain injury, with a latent period present between the brain injury and the first unprovoked seizure, the data described here show that seizure frequency was a sigmoid function of time after the insult in both animal models. Furthermore, the spontaneous recurrent seizures often occurred in clusters, even shortly after the first spontaneous seizure. These data suggest that (1) epileptogenesis is a continuous process that extends past the first spontaneous clinical seizure, (2) seizure clusters can obscure this continuous process, and (3) the potential time for administration of a therapy to suppress acquired epilepsy extends well past the first clinical seizure.
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Affiliation(s)
- F Edward Dudek
- Department of Physiology, University of Utah School of Medicine, 420 Chipeta Way, Suite 1700, Salt Lake City, UT 84108, United States.
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Kadam SD, White AM, Staley KJ, Dudek FE. Continuous electroencephalographic monitoring with radio-telemetry in a rat model of perinatal hypoxia-ischemia reveals progressive post-stroke epilepsy. J Neurosci 2010; 30:404-15. [PMID: 20053921 PMCID: PMC2903060 DOI: 10.1523/jneurosci.4093-09.2010] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 10/15/2009] [Accepted: 10/23/2009] [Indexed: 11/21/2022] Open
Abstract
The development of acquired epilepsy after a perinatal hypoxic-ischemic (HI) insult was investigated in rats. After unilateral carotid ligation with hypoxia on postnatal day 7, cortical electroencephalographic and behavioral seizures were recorded with continuous radio-telemetry and video. Chronic recordings were obtained between 2 and 12 months of age in freely behaving HI-treated and sham control rats. The hypotheses were that the acquired epilepsy is directly associated with an ischemic infarct (i.e., no lesion, no epilepsy), and the resultant epilepsy is temporally progressive. Every HI-treated rat with a cerebral infarct developed spontaneous epileptiform discharges and recurrent seizures (100%); in contrast, no spontaneous epileptiform discharges or seizures were detected with continuous monitoring in the HI-treated rats without infarcts. The initial seizures at 2 months generally showed focal onset and were nonconvulsive. Subsequent seizures had focal onsets that propagated to the homotopic contralateral cortex and were nonconvulsive or partial; later seizures often appeared to have bilateral onset and were convulsive. Spontaneous epileptiform discharges were initially lateralized to ipsilateral neocortex but became bilateral over time. The severity and frequency of the spontaneous behavioral and electrographic seizures progressively increased over time. In every epileptic rat, seizures occurred in distinct clusters with seizure-free periods as long as a few weeks. The progressive increase in seizure frequency over time was associated with increases in cluster frequency and seizures within each cluster. Thus, prolonged, continuous seizure monitoring directly demonstrated that the acquired epilepsy after perinatal HI was progressive with seizure clusters and was consistently associated with a cerebral infarct.
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Affiliation(s)
- Shilpa D. Kadam
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah 84108, and
| | - Andrew M. White
- Departments of Pediatrics and Neurology, University of Colorado Health Sciences Center, Denver, Colorado 80262
| | - Kevin J. Staley
- Departments of Pediatrics and Neurology, University of Colorado Health Sciences Center, Denver, Colorado 80262
| | - F. Edward Dudek
- Department of Biomedical Sciences, Colorado State University, Fort Collins, Colorado 80523
- Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah 84108, and
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Abstract
The lifespan risk of seizures is highest in the neonatal period. Current therapies have limited efficacy. Although the treatment of neonatal seizures has not changed significantly in the last several decades, there has been substantial progress in understanding developmental mechanisms that influence seizure generation and responsiveness to anticonvulsants. This article provides an overview of current approaches to the diagnosis and treatment of neonatal seizures, and some of the recent insights about the pathophysiology of neonatal seizures that may provide the foundation for better treatment are identified.
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Affiliation(s)
- Frances E Jensen
- Children's Hospital Boston, CLS 14073, 300 Longwood Avenue, Boston, MA 02115, USA.
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Aujla PK, Fetell MR, Jensen FE. Talampanel suppresses the acute and chronic effects of seizures in a rodent neonatal seizure model. Epilepsia 2009; 50:694-701. [PMID: 19220413 DOI: 10.1111/j.1528-1167.2008.01947.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
PURPOSE To test the efficacy of the novel candidate anticonvulsant talampanel (GYKI 53773) in a rodent model of hypoxic neonatal seizures. Talampanel is a noncompetitive antagonist of the alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid subtype of the glutamate receptor (AMPAR). We have previously shown that AMPARs play a critical role in the generation of acute seizures and later-life seizure susceptibility in this model of neonatal seizures. METHODS Seizures were induced in postnatal day (P) 10 Long-Evans rat pups by a 15 min exposure to global hypoxia. Acute seizure activity at P10 and subsequent susceptibility to seizure-induced neuronal injury with a "second-hit" kainate-induced seizure at P30-31 were compared between animals receiving talampanel (1, 5, 7.5, or 10 mg/kg) intraperitoneally (i.p.) versus saline vehicle treatment. RESULTS Talampanel treatment suppressed seizures in a dose-dependent manner, with maximal effect at 7.5 and 10 mg/kg. In addition, talampanel treatment 30 min before hypoxia prevented later-life increases in seizure-induced neuronal injury as assessed by in situ DNA nick end-labeling (ISEL). DISCUSSION We have previously demonstrated efficacy of other AMPAR antagonists such as NBQX and topiramate in this model. The present finding shows that the novel agent talampanel, under evaluation as an antiepileptic drug in children and adults, may have clinical potential in the treatment of neonatal seizures, particularly those occurring in the context of hypoxic encephalopathy.
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Affiliation(s)
- Paven K Aujla
- Department of Neurology, Children's Hospital Boston, Boston, Massachusetts 02115, USA
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Wang L, Greenfield LJ. Post-hypoxic changes in rat cortical neuron GABA A receptor function require L-type voltage-gated calcium channel activation. Neuropharmacology 2008; 56:198-207. [PMID: 18674547 DOI: 10.1016/j.neuropharm.2008.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Revised: 06/26/2008] [Accepted: 07/05/2008] [Indexed: 11/17/2022]
Abstract
Hypoxia modifies GABA(A) receptor (GABA(A)R) function and can cause seizures, encephalopathy or myoclonus. To characterize the effects of hypoxia on neuronal GABA(A)Rs, we subjected rat cortical neurons to 1% O2 for 2, 4 or 8h, followed by recovery times of 0-96h, and used whole-cell and perforated patch-clamp recording to assess GABA(A)R currents and pharmacology. Hypoxic exposure for 4h caused downregulation of maximal GABA current immediately following hypoxia and after 48h recovery without changing the EC50 for GABA. Two- and eight-hour hypoxic exposures had inconsistent effects on GABA(A)R currents. Maximal diazepam potentiation was increased immediately following 4h hypoxia, while potentiation by zolpidem was increased after 48h recovery. Pentobarbital enhancement and zinc inhibition of GABA currents were unchanged. Hypoxia also caused a depolarizing shift in the reversal potential of GABA-induced Cl(-) currents after 24h recovery. The L-type voltage-gated calcium channel (L-VGCC) blocker, nitrendipine, during hypoxia or control treatment prevented the reduction in GABA(A)R currents, and increased control currents over baseline. Nitrendipine also prevented the increase in zolpidem potentiation 48h after hypoxia, and blocked the depolarizing shift in Cl(-) reversal potential 24h after hypoxia. The effects of hypoxia on maximal GABA(A)R currents, zolpidem pharmacology and Cl(-) reversal potential thus require depolarization-induced calcium entry via L-VGCCs, and constitutive L-VGCC activity appears to reduce maximal GABA(A)R currents in control neurons via a calcium-dependent process. Calcium-dependent modulation of GABA(A)R currents via L-VGCCs may be a fundamental regulatory mechanism for GABA receptor function.
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Affiliation(s)
- Liping Wang
- Department of Neurology, University of Toledo College of Medicine, Health Science Campus, Toledo, OH 43614-2598, USA
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Abstract
One hundred ninety-three neonates with seizures were available on a neonatal seizure database, which included intrapartum and neonatal factors such as labor duration, fetal heart rate abnormalities, cord blood gas values, Apgar scores and clinical signs of encephalopathy. Regression analyses (analysis of variance) were performed on the entire cohort as well as specific subsets of neonates (eg, neonatal encephalopathy vs no encephalopathy) to assess the relationship between seizure timing and intrapartum/neonatal factors. Seizures were noted earlier for the encephalopathic group than for the nonencephalopathic group. No significant differences were noted for any intrapartum or neonatal factors. Timing of neonatal seizures, with or without an encephalopathy occurs within the first 2 days after birth and is independent of selected intrapartum and neonatal factors, underscoring recent task force recommendations concerning neonatal encephalopathy. Factors other than intrapartum events more likely contribute to the encephalopathic repertoire of the newborn, including seizures.
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Affiliation(s)
- Mark S Scher
- Rainbow Babies and Children's Hospital, Cleveland, Ohio 44106-6090, USA.
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Kaur C, Sivakumar V, Lu J, Tang FR, Ling EA. Melatonin attenuates hypoxia-induced ultrastructural changes and increased vascular permeability in the developing hippocampus. Brain Pathol 2008; 18:533-47. [PMID: 18422758 DOI: 10.1111/j.1750-3639.2008.00156.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Hypoxic injury in the perinatal period may be involved in damaging the developing hippocampus. The damage may be mediated by excess production of vascular endothelial growth factor (VEGF) and nitric oxide (NO). We examined the hippocampus of neonatal Wistar rats subjected to hypoxia for VEGF and NO production. The mRNA and protein expression of hypoxia inducible factor-1alpha, endothelial, neuronal, inducible nitric oxide synthase and VEGF was found to be up-regulated significantly after the hypoxic exposure. Tissue VEGF concentration and NO production were also increased. By electron microscopy, swollen dendrites, vacuolated axons and hypertrophic astrocyte end feet associated with blood vessels were observed in hypoxic animals. In hypoxic rats, the passage of rhodamine isothiocyanate (RhIC) and horseradish peroxidase, administered intraperitoneally or intravenously, was observed through vascular walls. Furthermore, immunoglobulin G was localized in the neuropil and neurons. We suggest that increased VEGF and NO production in hypoxia had resulted in increased vascular permeability, leading to structural alteration of the dendrites and axons. Melatonin administration reduced VEGF and NO levels as well as leakage of RhIC, suggesting that it has a therapeutic potential in reducing hypoxia-associated damage in the developing hippocampus.
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Affiliation(s)
- Charanjit Kaur
- Department of Anatomy, Yong Loo Lin School of Medicine, Blk MD10, 4 Medical Drive, National University of Singapore, Singapore.
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Masri A, Badran E, Hamamy H, Assaf A, Al-Qudah AA. Etiologies, outcomes, and risk factors for epilepsy in infants: A case–control study. Clin Neurol Neurosurg 2008; 110:352-6. [DOI: 10.1016/j.clineuro.2007.12.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2007] [Revised: 12/05/2007] [Accepted: 12/15/2007] [Indexed: 11/28/2022]
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KADAM SHILPAD, DUDEK FEDWARD. Neuropathogical features of a rat model for perinatal hypoxic-ischemic encephalopathy with associated epilepsy. J Comp Neurol 2007; 505:716-37. [PMID: 17948865 PMCID: PMC4607042 DOI: 10.1002/cne.21533] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Hypoxic-ischemic (HI) encephalopathy is an important neurological problem of the perinatal period. Little is known of the long-term progression of HI insults or the maladaptive changes that lead to epilepsy. Using rats with unilateral carotid occlusion followed by hypoxia at postnatal day 7, this study provides an initial analysis of the epilepsy caused by a perinatal HI insult with chronic and continuous behavioral monitoring. The histopathology was investigated at postnatal day 30 and later at > or =6 months of age using cresyl violet, Timm, and rapid Golgi staining and immunocytochemistry. The resultant epilepsy showed an increase in seizure frequency over time, with a preponderance for seizure clusters and behavioral features of an ipsilateral cerebral syndrome. In addition to parasagittal infarcts and porencephalic cysts in severe lesions, columnar neuronal death was found with cytomegaly in isolated groups of dysmorphic cortical neurons. Cortical dysgenesis was seen in the form of deep laminar cell loss, microgyri, white matter hypercellularity, and blurring of the white and gray matter junction. Mossy fiber sprouting was not only detected in the atrophied ipsilateral dorsal hippocampus of HI rats with chronic epilepsy, but was also found in comparable grades in spared ipsi- and contralateral ventral hippocampi. The cortical lesions in this animal model show histological similarities with those found in humans after perinatal HI. The occurrence of cortical abnormalities that are associated with epilepsy in humans correlates with the consequent detection of spontaneous recurrent seizures.
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Affiliation(s)
- SHILPA D. KADAM
- Department of Biomedical Sciences, Neurosciences Division, Colorado State University, Fort Collins, Colorado 80523, and Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah 84108
| | - F. EDWARD DUDEK
- Department of Biomedical Sciences, Neurosciences Division, Colorado State University, Fort Collins, Colorado 80523, and Department of Physiology, University of Utah School of Medicine, Salt Lake City, Utah 84108
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Cansu A, Serdaroğlu A, Yüksel D, Doğan V, Ozkan S, Hirfanoğlu T, Senbil N, Gücüyener K, Soysal S, Camurdan A, Gürer YK. Prevalence of some risk factors in children with epilepsy compared to their controls. Seizure 2007; 16:338-44. [PMID: 17391991 DOI: 10.1016/j.seizure.2007.02.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2006] [Revised: 11/13/2006] [Accepted: 02/20/2007] [Indexed: 10/23/2022] Open
Abstract
AIM The goal of this case-control study was to identify the significance of certain risk factors for epilepsy in Turkey. METHOD A total of 805 cases, aged 1-16 years, followed-up for epilepsy at the Pediatric Neurology Department and a control group consisting of 846 age-matched cases without epilepsy were included in the study. The risk factors examined were gender, neurological impairment, febrile convulsion, head trauma, central nervous system infections, parental consanguinity, family history of epilepsy, prenatal and natal risk and newborn jaundice. Data regarding the investigated epilepsy risk factors were obtained through a questionnaire via personal interviews and the medical records and were assessed using univariate and multivariate analysis. RESULT Univariate analysis showed an increased risk for epilepsy with a history of atypical febrile seizure (21.97-fold), severe and moderate head injury (27.76- and 7.09-fold respectively), CNS infection (4.76-fold), history of epilepsy in first-, second- or third-degree relatives (6.42-, 3.09- and 2.66-fold, respectively), presence of maternal hypertension (4.31-fold), an apgar score < or =6 at any time (7.78-fold) and neonatal jaundice (3.12-fold). Abnormal neurological signs increased the epilepsy risk 5.92 times in univariate analysis and 30.26 times in multivariate analysis. CONCLUSION The most important risk factors for epilepsy in this study were neurological impairment, history of atypical febrile seizures, severe head injury and a low apgar score. Other important risk factors were moderate head trauma and a history of epilepsy in the family.
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Affiliation(s)
- Ali Cansu
- Gazi University Faculty of Medicine, Department of Pediatric Neurology, Ankara, Turkey.
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Humphreys P, Deonandan R, Whiting S, Barrowman N, Matzinger MA, Briggs V, Hurteau J, Wallace E. Factors associated with epilepsy in children with periventricular leukomalacia. J Child Neurol 2007; 22:598-605. [PMID: 17690068 DOI: 10.1177/0883073807302599] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Children with cerebral palsy associated with periventricular leukomalacia frequently develop unprovoked epileptic seizures. This article reports an analysis of risk factors for epilepsy in children with radiologically confirmed periventricular leukomalacia. This cohort was screened for epilepsy and for an array of clinical and demographic factors. Of 154 subjects with radiologically confirmed periventricular leukomalacia, 40 (26.0%) had epilepsy. In the epileptic group, radiologic pathology other than periventricular leukomalacia was uncommon. Significant associations were found between epilepsy and cerebral palsy patterns other than spastic diparesis, mental handicap, cortical visual impairment, neonatal seizures, and severe periventricular leukomalacia. Only the presence of neonatal seizures was significantly associated with epilepsy once other risk factors were controlled in the regression model. Some previous studies have shown an association between neonatal seizures and later epilepsy for cerebral palsy in general. This is the first report of such an association for a single predominant type of cerebral pathology.
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Affiliation(s)
- Peter Humphreys
- Division of Neurology, Department of Pediatrics, Children's Hospital of Eastern Ontario, Ottawa Children's Treatment Centre Ottawa, Ontario, Canada.
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Abstract
UNLABELLED Seizures in neonates (NBs) remain the most frequent neurological problem in the nursery. Considerable debate about their consequences exists between data and deductions reached through animal experimentations and those obtained through clinical investigations. The main conflicting issues are whether seizures in NBs can plant the roots for epileptogenesis and cause long-term deficits. The purpose of this chapter is to evaluate both laboratory and clinical results. METHODS Clinical data will be presented, including a 20-year-long cohort of NBs. This will be followed by the main seminal discoveries obtained in neonatal models. The phenomenon of transient or persistent dysmaturity following NB seizures will be discussed in relation to etiological factors. RESULTS The findings and deductions from animal models support the notions that epileptogenesis and cognitive deficits result from NB seizures. These conclusions contrast with clinical investigations maintaining that NB seizures, per se, are symptomatic markers of preexisting or of ongoing morbidities. The reasons for contrasting views will be discussed. Suggestions will be advanced for more animal models whose seizures are consistent with the etiologies and the phenotypes of human NB seizures.
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Affiliation(s)
- Cesare T Lombroso
- Department of Neurology, Children's Hospital and Department of Neurology, Harvard Medical School, Boston, Massachusetts, USA.
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41
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Sanchez RM, Justice JA, Zhang K. Persistently decreased basal synaptic inhibition of hippocampal CA1 pyramidal neurons after neonatal hypoxia-induced seizures. Dev Neurosci 2007; 29:159-67. [PMID: 17148958 DOI: 10.1159/000096220] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2006] [Accepted: 04/18/2006] [Indexed: 11/19/2022] Open
Abstract
Hypoxia is the most common cause of neonatal seizures and can lead to epilepsy, but the epileptogenic mechanisms are not yet understood. We have previously shown that hypoxia-induced seizures in the neonatal rat result in acutely decreased amplitudes and frequency of spontaneous and miniature inhibitory postsynaptic currents (sIPSCs and mIPSCs) in hippocampal CA1 pyramidal neurons. In the current study, we asked whether such changes persist for several days following hypoxia-induced seizures. Similar to the acute findings, we observed decreased frequency and amplitudes of sIPSCs and decreased mIPSC amplitudes in CA1 pyramidal neurons at 3-5 days after hypoxia. However, in contrast to the acute findings, we observed no differences between hypoxia-treated and control groups in mIPSC frequency. Additionally, by 7 days after hypoxia, sIPSC amplitudes in the hypoxia group had recovered to control levels, but sIPSC frequency remained decreased. These data indicate that the persistently decreased sIPSC frequency result from decreased firing of presynaptic inhibitory interneurons, with only transient possible changes in postsynaptic responses to GABA release.
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Affiliation(s)
- Russell M Sanchez
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, TX 78229-3900, USA.
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Reime Kinjo E, Arida RM, Mara de Oliveira D, da Silva Fernandes MJ. The Na+/K+ATPase activity is increased in the hippocampus after multiple status epilepticus induced by pilocarpine in developing rats. Brain Res 2006; 1138:203-7. [PMID: 17270150 DOI: 10.1016/j.brainres.2006.12.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 12/18/2006] [Accepted: 12/22/2006] [Indexed: 11/30/2022]
Abstract
The effects of repetitive pilocarpine-induced status epilepticus (SE) in the hippocampal Na(+)/K(+)ATPase activity were studied in developing rat. Na(+)/K(+)ATPase is a membrane-bound enzyme responsible for the active transport of sodium and potassium ions through the membrane. It is necessary to maintain neuronal excitability. The malfunction of this enzyme has been associated with neuronal hyperexcitability. The pilocarpine-induced status epilepticus in developing rats leads to neuronal hyperexcitability and brain damage. We examined the activity of the Na(+)/K(+)ATPase enzyme in hippocampus of rats submitted to 1 episode of status epilepticus on postnatal day 9 and to 3 episodes of pilocarpine-induced status epilepticus on postnatal days 7, 8 and 9. Our findings showed that one status epilepticus episode does not modify the Na(+)/K(+)ATPase activity in hippocampus of rats studied 7 or 30 days later (at P16 or P39). However, an increase in the Na(+)/K(+)ATPase activity was detected in hippocampus of rats submitted to three consecutive status epilepticus during the development studied 7 (+142%) and 30 (+400%) days following the injections. In addition, a significant reduction in the Na(+)/K(+)ATPase activity was observed in control rats at P39 compared to P16. Our data suggest that multiple pilocarpine-induced status epilepticus in developing rats induce long-lasting increase in the Na(+)/K(+)ATPase activity in the hippocampus, reflecting hyperexcitability.
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Affiliation(s)
- Erika Reime Kinjo
- Depto. de Neurologia e Neurocirurgia, Disciplina de Neurologia Experimental, Universidade Federal de São Paulo, Unifesp. Rua Botucatu, 862 - Edif. Leal Prado, CEP 04023-900, São Paulo, Brazil
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43
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McNamara JO, Huang YZ, Leonard AS. Molecular signaling mechanisms underlying epileptogenesis. ACTA ACUST UNITED AC 2006; 2006:re12. [PMID: 17033045 DOI: 10.1126/stke.3562006re12] [Citation(s) in RCA: 165] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Epilepsy, a disorder of recurrent seizures, is a common and frequently devastating neurological condition. Available therapy is only symptomatic and often ineffective. Understanding epileptogenesis, the process by which a normal brain becomes epileptic, may help identify molecular targets for drugs that could prevent epilepsy. A number of acquired and genetic causes of this disorder have been identified, and various in vivo and in vitro models of epileptogenesis have been established. Here, we review current insights into the molecular signaling mechanisms underlying epileptogenesis, focusing on limbic epileptogenesis. Study of different models reveals that activation of various receptors on the surface of neurons can promote epileptogenesis; these receptors include ionotropic and metabotropic glutamate receptors as well as the TrkB neurotrophin receptor. These receptors are all found in the membrane of a discrete signaling domain within a particular type of cortical neuron--the dendritic spine of principal neurons. Activation of any of these receptors results in an increase Ca2+ concentration within the spine. Various Ca2+-regulated enzymes found in spines have been implicated in epileptogenesis; these include the nonreceptor protein tyrosine kinases Src and Fyn and a serine-threonine kinase [Ca2+-calmodulin-dependent protein kinase II (CaMKII)] and phosphatase (calcineurin). Cross-talk between astrocytes and neurons promotes increased dendritic Ca2+ and synchronous firing of neurons, a hallmark of epileptiform activity. The hypothesis is proposed that limbic epilepsy is a maladaptive consequence of homeostatic responses to increases of Ca2+ concentration within dendritic spines induced by abnormal neuronal activity.
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Affiliation(s)
- James O McNamara
- Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
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Zhang K, Peng BW, Sanchez RM. Decreased IH in Hippocampal Area CA1 Pyramidal Neurons after Perinatal Seizure-inducing Hypoxia. Epilepsia 2006; 47:1023-8. [PMID: 16822248 DOI: 10.1111/j.1528-1167.2006.00574.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
PURPOSE The hyperpolarization-activated cation current (IH) has been proposed to play a role in some forms of epileptogenesis, as it critically regulates synaptic integration and intrinsic excitability of principal limbic neurons and can be pathologically altered after experimentally induced seizures. In hippocampal CA1 pyramidal neurons, IH is functionally decreased after kainate-induced status epilepticus in adult rats but is increased after hyperthermia-induced seizures in immature rat pups. This study aimed to determine whether and how IH may be altered in CA1 pyramidal neurons after seizure-inducing global hypoxia in the neonatal brain. METHODS Seizures were induced in rat pups on postnatal day 10 by 14- to 16-min exposure to 5-7% O2. Whole-cell patch-clamp recordings were obtained from hippocampal CA1 pyramidal neurons in slices 30 min to 3 days after hypoxia treatment, and from control age-matched littermates. IH was isolated under voltage-clamp by subtracting current responses to hyperpolarizing voltage steps before and during application of the IH blocker ZD 7288 (100 microM). RESULTS IH was significantly decreased in pyramidal neurons from the hypoxia-treated group compared with controls (p<0.001; 19 controls; 15 hypoxia). Analyses of tail currents and activation kinetics indicated no statistically significant differences between groups in the voltage dependence or time constants of activation. CONCLUSIONS These data indicate that a single episode of neonatal hypoxia that induces seizures can persistently decrease IH in CA1 pyramidal neurons, raising this as a potential contributing mechanism to epileptogenesis in this setting. Our findings further indicate that the consequences of seizures for IH may depend more on seizure etiology than on maturational stage.
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Affiliation(s)
- Kun Zhang
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
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45
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Levin SG, Godukhin OV. Hyperexcitability of pyramidal neurons in field CA1 in hippocampal slices from rats evoked by episodes of hypoxia: The roles of GABAA and GABAB receptors. ACTA ACUST UNITED AC 2006; 36:415-8. [PMID: 16583170 DOI: 10.1007/s11055-006-0033-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2004] [Revised: 09/10/2004] [Indexed: 10/24/2022]
Affiliation(s)
- S G Levin
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region.
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46
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Sanchez RM, Dai W, Levada RE, Lippman JJ, Jensen FE. AMPA/kainate receptor-mediated downregulation of GABAergic synaptic transmission by calcineurin after seizures in the developing rat brain. J Neurosci 2006; 25:3442-51. [PMID: 15800199 PMCID: PMC6724904 DOI: 10.1523/jneurosci.0204-05.2005] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hypoxia is the most common cause of perinatal seizures and can be refractory to conventional anticonvulsant drugs, suggesting an age-specific form of epileptogenesis. A model of hypoxia-induced seizures in immature rats reveals that seizures result in immediate activation of the phosphatase calcineurin (CaN) in area CA1 of hippocampus. After seizures, CA1 pyramidal neurons exhibit a downregulation of GABA(A) receptor (GABA(A)R)-mediated inhibition that was reversed by CaN inhibitors. CaN activation appears to be dependent on seizure-induced activation of Ca2+-permeable AMPA receptors (AMPARs), because the upregulation of CaN activation and GABA(A)R inhibition were attenuated by GYKI 52466 [1-(4-aminophenyl)-4-methyl-7,8-methylenedioxy-5H-2,3-benzodiazepine hydrochloride] or Joro spider toxin. GABA(A)R beta2/3 subunit protein was dephosphorylated at 1 h after seizures, suggesting this subunit as a possible substrate of CaN in this model. Finally, in vivo administration of the CaN inhibitor FK-506 significantly suppressed hypoxic seizures, and posttreatment with NBQX (2,3-dihydroxy-6-nitro-7-sulfonyl-benzo[f]quinoxaline) or FK-506 blocked the hypoxic seizure-induced increase in CaN expression. These data suggest that Ca2+-permeable AMPARs and CaN regulate inhibitory synaptic transmission in a novel plasticity pathway that may play a role in epileptogenesis in the immature brain.
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Affiliation(s)
- Russell M Sanchez
- Department of Pharmacology and Center for Biomedical Neuroscience, University of Texas Health Science Center, San Antonio, Texas 78229-3900, USA
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47
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Levin SG, Godukhin OV. Changes in the excitability of pyramidal neurons in hippocampal slices from aged rats in conditions of periodic transient episodes of hypoxia. NEUROSCIENCE AND BEHAVIORAL PHYSIOLOGY 2005; 35:937-41. [PMID: 16270176 DOI: 10.1007/s11055-005-0149-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Revised: 05/10/2004] [Indexed: 11/30/2022]
Affiliation(s)
- S G Levin
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290, Pushchino, Moscow Region, Russia.
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48
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Kim DS, Kwak SE, Kim JE, Won MH, Choi HC, Song HK, Kwon OS, Kim YI, Choi SY, Kang TC. Bilateral enhancement of excitation via up-regulation of vesicular glutamate transporter subtype 1, not subtype 2, immunoreactivity in the unilateral hypoxic epilepsy model. Brain Res 2005; 1055:122-30. [PMID: 16083865 DOI: 10.1016/j.brainres.2005.06.081] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2005] [Revised: 06/30/2005] [Accepted: 06/30/2005] [Indexed: 10/25/2022]
Abstract
In the present study, the change of vesicular glutamate transporter (VGLUT) immunoreactivity on long-term impaired excitability in the hippocampus after recovery from unilateral hypoxic-ischemic insult was investigated in order to extend our understanding of the mechanism of epileptogenesis using unilateral hypoxic epilepsy models. Both the lesioned (submitted to ischemia) and the unlesioned hippocampi exhibited the frequent occurrence of interictal spikes and occasionally the sustained ictal discharges. However, paired-pulse inhibition was significantly reduced in the unlesioned dentate gyrus, not in the lesioned dentate gyrus. VGLUT1 immunoreactivity was significantly elevated in both hippocampi following hypoxic ischemia, although VGLUT2 immunodensity was unaltered. These findings suggest that the enhancement of VGLUT1 immunoreactivity in both hippocampi after unilateral hypoxic ischemia may contribute to the hyperexcitability, which may play an important role in the epileptogenesis (presumably accompanied by altered inhibitory transmission) after neurodegeneration.
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Affiliation(s)
- Duk-Soo Kim
- Department of Anatomy, College of Medicine, Hallym University, Chunchon, Kangwon-Do 200-702, South Korea
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49
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Mastrangelo M, Van Lierde A, Bray M, Pastorino G, Marini A, Mosca F. Epileptic seizures, epilepsy and epileptic syndromes in newborns: A nosological approach to 94 new cases by the 2001 proposed diagnostic scheme for people with epileptic seizures and with epilepsy. Seizure 2005; 14:304-11. [PMID: 15871921 DOI: 10.1016/j.seizure.2005.04.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2004] [Indexed: 10/25/2022] Open
Abstract
PURPOSE To assess the advantages of the 2001 ILAE proposed diagnostic scheme for classification of newborns with epileptic seizures over the 1989 ILAE classification. METHOD Clinical features, seizure semiology and duration, neurological evaluation, ictal and interictal EEG, brain imaging and outcome at the end of the neonatal period (44 weeks post-conceptional age) of 94 newborns with EEG confirmed seizures were analyzed. The 2001 ILAE classification was applied where possible. RESULTS Twenty patients died before the end of the neonatal period. In the remaining patients, applying axis 3, we classified 54 newborns as having epileptic seizures that do not require a diagnosis of epilepsy; 14 as symptomatic partial epilepsy; 5 within the neonatal epileptic syndromes and one as benign neonatal seizures (NS). Axis 4 in all newborns provided a valuable tool in order to better define the individual patient. CONCLUSIONS Compared to the 1989 ILAE classification, which allowed a syndromic diagnosis in only 6/94 patients, the remaining being classified as Epilepsies and Syndromes undetermined whether focal or generalized, the 2001 ILAE diagnostic scheme, applied at the end of the neonatal period, offers a variety of approaches to classification, allowing an early distinction between epilepsy and single or isolated clusters of seizures, with therapeutic and prognostic implications.
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Affiliation(s)
- Massimo Mastrangelo
- U.O. Neurologia-Neurofisiopatologia, ICP Clinica Mangiagalli, Via Commenda 12, 20122 Milano, Italy.
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50
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Levin SG, Kalemenev SV, Godukhin OV. Hyperexcitability of Neurons in Field Ca1 Evoked by Transient Episodes of Hypoxia in Hippocampal Slices from Rats of Different Ages. ACTA ACUST UNITED AC 2005; 35:585-8. [PMID: 16342614 DOI: 10.1007/s11055-005-0097-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- S G Levin
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 142290 Pushchino, Moscow Region, Russia
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