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Santos AC, Nader G, El Soufi El Sabbagh D, Urban K, Attisano L, Carlen PL. Treating Hyperexcitability in Human Cerebral Organoids Resulting from Oxygen-Glucose Deprivation. Cells 2023; 12:1949. [PMID: 37566028 PMCID: PMC10416870 DOI: 10.3390/cells12151949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Revised: 07/13/2023] [Accepted: 07/21/2023] [Indexed: 08/12/2023] Open
Abstract
Human cerebral organoids resemble the 3D complexity of the human brain and have the potential to augment current drug development pipelines for neurological disease. Epilepsy is a complex neurological condition characterized by recurrent seizures. A third of people with epilepsy do not respond to currently available pharmaceutical drugs, and there is not one drug that treats all subtypes; thus, better models of epilepsy are needed for drug development. Cerebral organoids may be used to address this unmet need. In the present work, human cerebral organoids are used along with electrophysiological methods to explore oxygen-glucose deprivation as a hyperexcitability agent. This activity is investigated in its response to current antiseizure drugs. Furthermore, the mechanism of action of the drug candidates is probed with qPCR and immunofluorescence. The findings demonstrate OGD-induced hyperexcitable changes in the cerebral organoid tissue, which is treated with cannabidiol and bumetanide. There is evidence for NKCC1 and KCC2 gene expression, as well as other genes and proteins involved in the complex development of GABAergic signaling. This study supports the use of organoids as a platform for modelling cerebral cortical hyperexcitability that could be extended to modelling epilepsy and used for drug discovery.
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Affiliation(s)
- Alexandra C. Santos
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - George Nader
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
| | - Dana El Soufi El Sabbagh
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
- Department of Pharmacology and Toxicology, University of Toronto, Toronto, ON M5S 1A1, Canada
| | | | - Liliana Attisano
- Department of Biochemistry, University of Toronto, Toronto, ON M5S 1A1, Canada
- Donnelly Centre, University of Toronto, Toronto, ON M5S 1A1, Canada
| | - Peter L. Carlen
- Krembil Research Institute, University Health Network, Toronto, ON M5S 0T8, Canada (P.L.C.)
- Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 1A1, Canada
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Johnson KJ, Moy B, Rensing N, Robinson A, Ly M, Chengalvala R, Wong M, Galindo R. Functional neuropathology of neonatal hypoxia-ischemia by single-mouse longitudinal electroencephalography. Epilepsia 2022; 63:3037-3050. [PMID: 36054439 PMCID: PMC10176800 DOI: 10.1111/epi.17403] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Neonatal cerebral hypoxia-ischemia (HI) results in symptomatic seizures and long-term neurodevelopmental disability. The Rice-Vannucci model of rodent neonatal HI has been used extensively to examine and translate the functional consequences of acute and chronic HI-induced encephalopathy. Yet, longitudinal electrophysiological characterization of this brain injury model has been limited by the size of the neonatal mouse's head and postnatal maternal dependency. We overcome this challenge by employing a novel method of longitudinal single-mouse electroencephalography (EEG) using chronically implanted subcranial electrodes in the term-equivalent mouse pup. We characterize the neurophysiological disturbances occurring during awake and sleep states in the acute and chronic phases following newborn brain injury. METHODS C57BL/6 mice underwent long-term bilateral subcranial EEG and electromyographic electrode placement at postnatal day 9 followed by unilateral carotid cauterization and exposure to 40 minutes of hypoxia the following day. EEG recordings were obtained prior, during, and intermittently after the HI procedure from postnatal day 10 to weaning age. Quantitative EEG and fast Fourier transform analysis were used to evaluate seizures, cortical cerebral dysfunction, and disturbances in vigilance states. RESULTS We observed neonatal HI-provoked electrographic focal and bilateral seizures during or immediately following global hypoxia and most commonly contralateral to the ischemic injury. Spontaneous chronic seizures were not seen. Injured mice developed long-term asymmetric EEG background attenuation in all frequencies and most prominently during non-rapid eye movement (NREM) sleep. HI mice also showed transient impairments in vigilance state duration and transitions during the first 2 days following injury. SIGNIFICANCE The functional burden of mouse neonatal HI recorded by EEG resembles closely that of the injured human newborn. The use of single-mouse longitudinal EEG in this immature model can advance our understanding of the developmental and pathophysiological mechanisms of neonatal cerebral injury and help translate novel therapeutic strategies against this devastating condition.
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Affiliation(s)
- Kevin J Johnson
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Brianna Moy
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Nicholas Rensing
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Alexia Robinson
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael Ly
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ramya Chengalvala
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael Wong
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rafael Galindo
- Department of Neurology, Division of Pediatric & Developmental Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
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Zayachkivsky A, Lehmkuhle MJ, Ekstrand JJ, Dudek FE. Background suppression of electrical activity is a potential biomarker of subsequent brain injury in a rat model of neonatal hypoxia-ischemia. J Neurophysiol 2022; 128:118-130. [PMID: 35675445 DOI: 10.1152/jn.00024.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Electrographic seizures and abnormal background activity in the neonatal electroencephalogram (EEG) may differentiate between harmful versus benign brain insults. Using two animal models of neonatal seizures, electrical activity was recorded in freely behaving rats and examined quantitatively during successive time periods with field-potential recordings obtained shortly after the brain insult (i.e., 0-4 days). Single-channel, differential recordings with miniature wireless telemetry were used to analyze spontaneous electrographic seizures and background suppression of electrical activity after 1) hypoxia-ischemia (HI), which is a model of neonatal encephalopathy that causes acute seizures and a large brain lesion with possible development of epilepsy, 2) hypoxia alone (Ha), which causes severe acute seizures without an obvious lesion or subsequent epilepsy, and 3) sham control rats. Background EEG exhibited increases in power as a function of age in control animals. Although background electrical activity was depressed in all frequency bands immediately after HI, suppression in the β and γ bands was greatest and lasted longest. Spontaneous electrographic seizures were recorded, but only in a few HI-treated animals. Ha-treated rat pups were similar to sham controls, they had no subsequent spontaneous electrographic seizures after the treatment and background suppression was only briefly observed in one frequency band. Thus, the normal age-dependent maturation of electrical activity patterns in control animals was significantly disrupted after HI. Suppression of the background EEG observed here after HI-induced acute seizures and subsequent brain injury may be a noninvasive biomarker for detecting severe brain injuries and may help predict subsequent epilepsy.NEW & NOTEWORTHY Biomarkers of neonatal brain injury are needed. Hypoxia-ischemia (HI) in immature rat pups caused severe brain injury, which was associated with strongly suppressed background EEG. The suppression was most robust in the β and γ bands; it started immediately after the HI injury and persisted for days. Thus, background suppression may be a noninvasive biomarker for detecting severe brain injuries and may help predict subsequent epilepsy.
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Affiliation(s)
- A Zayachkivsky
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - M J Lehmkuhle
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
| | - J J Ekstrand
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - F E Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah
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Sun X, Xue F, Wen J, Gao L, Li Y, Jiang Q, Yang L, Cui H. Seizure Characteristics and Background Amplitude-Integrated Electroencephalography Activity in Neonatal Rats Subjected to Hypoxia-Ischemia. Front Pediatr 2022; 10:837909. [PMID: 35463911 PMCID: PMC9021695 DOI: 10.3389/fped.2022.837909] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 02/14/2022] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVE Perinatal hypoxic-ischemic encephalopathy (HIE) is a major cause of epilepsy and chronic neurologic morbidity in premature infants. This study aimed to investigate the characteristics of acute seizures and the pattern of background activity on amplitude-integrated electroencephalography (aEEG) in neonatal rats with HIE. METHODS Hypoxia-ischemia (HI) was induced in postnatal day (P) 3 neonatal rats (n = 12) by ligation of the left carotid artery and exposure to airtight hypoxia for 2 h. Data regarding seizure type, frequency, and duration and those related to neurobehavioral development were collected, and the integrated power of background EEG was analyzed to evaluate the effect of HI. RESULTS All neonatal rats in the HI group experienced frequent seizures during hypoxia, and 83.3% of rats (10/12) experienced seizures immediately after hypoxia. Seizure frequency and duration gradually decreased with increasing age. The mortality rate of the HI group was 8.33% (1/12); 120 h after HI induction, only 27.3% (3/11) of pups had low-frequency and short-duration electrographic seizures, respectively. HI rats, which presented seizure activities 96 h after HI insult, exhibited an increase in righting reflex time and a decrease in forelimb grip reflex time. Background EEG was significantly inhibited during HI induction and immediately after hypoxia and gradually recovered 72 h after hypoxia. CONCLUSION Seizures caused by HI brain damage in premature infants can be simulated in the P3 neonatal rat model.
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Affiliation(s)
- Xiaowei Sun
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Fenqin Xue
- Core Facility Center, Capital Medical University, Beijing, China
| | - Jialin Wen
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Limin Gao
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Yang Li
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Qianqian Jiang
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Lijun Yang
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
| | - Hong Cui
- Department of Pediatrics, Beijing Friendship Hospital, Capital Medical University, Beijing, China
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Ala‐Kurikka T, Pospelov A, Summanen M, Alafuzoff A, Kurki S, Voipio J, Kaila K. A physiologically validated rat model of term birth asphyxia with seizure generation after, not during, brain hypoxia. Epilepsia 2021; 62:908-919. [PMID: 33338272 PMCID: PMC8246723 DOI: 10.1111/epi.16790] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 11/24/2020] [Accepted: 11/24/2020] [Indexed: 01/05/2023]
Abstract
OBJECTIVE Birth asphyxia (BA) is often associated with seizures that may exacerbate the ensuing hypoxic-ischemic encephalopathy. In rodent models of BA, exposure to hypoxia is used to evoke seizures, that commence already during the insult. This is in stark contrast to clinical BA, in which seizures are typically seen upon recovery. Here, we introduce a term-equivalent rat model of BA, in which seizures are triggered after exposure to asphyxia. METHODS Postnatal day 11-12 male rat pups were exposed to steady asphyxia (15 min; air containing 5% O2 + 20% CO2 ) or to intermittent asphyxia (30 min; three 5 + 5-min cycles of 9% and 5% O2 at 20% CO2 ). Cortical activity and electrographic seizures were recorded in freely behaving animals. Simultaneous electrode measurements of intracortical pH, Po2 , and local field potentials (LFPs) were made under urethane anesthesia. RESULTS Both protocols decreased blood pH to <7.0 and brain pH from 7.3 to 6.7 and led to a fall in base excess by 20 mmol·L-1 . Electrographic seizures with convulsions spanning the entire Racine scale were triggered after intermittent but not steady asphyxia. In the presence of 20% CO2 , brain Po2 was only transiently affected by 9% ambient O2 but fell below detection level during the steps to 5% O2 , and LFP activity was nearly abolished. Post-asphyxia seizures were strongly suppressed when brain pH recovery was slowed down by 5% CO2 . SIGNIFICANCE The rate of brain pH recovery has a strong influence on post-asphyxia seizure propensity. The recurring hypoxic episodes during intermittent asphyxia promote neuronal excitability, which leads to seizures only after the suppressing effect of the hypercapnic acidosis is relieved. The present rodent model of BA is to our best knowledge the first one in which, consistent with clinical BA, behavioral and electrographic seizures are triggered after and not during the BA-mimicking insult.
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Affiliation(s)
- Tommi Ala‐Kurikka
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Alexey Pospelov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Milla Summanen
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Aleksander Alafuzoff
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Samu Kurki
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
| | - Juha Voipio
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
| | - Kai Kaila
- Faculty of Biological and Environmental Sciences, Molecular and Integrative BiosciencesUniversity of HelsinkiHelsinkiFinland
- Neuroscience Center (HiLIFE)University of HelsinkiHelsinkiFinland
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Raol YH, Joksimovic SM, Sampath D, Matter BA, Lam PM, Kompella UB, Todorovic SM, González MI. The role of KCC2 in hyperexcitability of the neonatal brain. Neurosci Lett 2020; 738:135324. [PMID: 32860887 PMCID: PMC7584761 DOI: 10.1016/j.neulet.2020.135324] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/20/2020] [Accepted: 08/24/2020] [Indexed: 11/25/2022]
Abstract
BACKGROUND The hyperpolarizing activity of γ-aminobutyric acid A (GABAA) receptors depends on the intracellular chloride gradient that is developmentally regulated by the activity of the chloride extruder potassium (K) chloride (Cl) cotransporter 2 (KCC2). In humans and rodents, KCC2 expression can be detected at birth. In rodents, KCC2 expression progressively increases and reaches adult-like levels by the second postnatal week of life. Several studies report changes in KCC2 expression levels in response to early-life injuries. However, the functional contribution of KCC2 in maintaining the excitation-inhibition balance in the neonatal brain is not clear. In the current study, we examined the effect of KCC2 antagonism on the neonatal brain activity under hyperexcitable conditions ex vivo and in vivo. METHODS Ex vivo electrophysiology experiments were performed on hippocampal slices prepared from 7 to 9 days-old (P7-P9) male rats. Excitability of CA1 pyramidal neurons bathed in zero-Mg2+ buffer was measured using single-unit extracellular (loose) or cell-attach protocol before and after application of VU0463271, a specific antagonist of KCC2. To examine the functional role of KCC2 in vivo, the effect of VU0463271 on hypoxia-ischemia (HI)-induced ictal (seizures and brief runs of epileptiform discharges - BREDs), and inter-ictal spike and sharp-wave activity was measured in P7 male rats. A highly sensitive LC-MS/MS method was used to determine the distribution and the concentration of VU0463271 in the brain. RESULTS Ex vivo blockade of KCC2 by VU0463271 significantly increased the frequency of zero-Mg2+-triggered spiking in CA1 pyramidal neurons. Similarly, in vivo administration of VU0463271 significantly increased the number of ictal events, BREDs duration, and spike and sharp-wave activity in HI rats. LC-MS/MS data revealed that following systemic administration, VU0463271 rapidly reached brain tissues and distributed well among different brain regions. CONCLUSION The results suggest that KCC2 plays a critical functional role in maintaining the balance of excitation-inhibition in the neonatal brain, and thus it can be used as a therapeutic target to ameliorate injury associated with hyperexcitability in newborns.
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Affiliation(s)
- Yogendra H Raol
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Srdjan M Joksimovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Dayalan Sampath
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Brock A Matter
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Philip M Lam
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Uday B Kompella
- Department of Pharmaceutical Sciences, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Slobodan M Todorovic
- Department of Anesthesiology, University of Colorado Anschutz Medical Campus, Aurora, CO, USA
| | - Marco I González
- Department of Pediatrics, Division of Neurology, School of Medicine, Translational Epilepsy Research Program, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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Effects of a potassium channel opener on brain injury and neurologic outcomes in an animal model of neonatal hypoxic-ischemic injury. Pediatr Res 2020; 88:202-208. [PMID: 31896131 PMCID: PMC7329576 DOI: 10.1038/s41390-019-0734-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 12/21/2022]
Abstract
BACKGROUND Hypoxia-ischemia (HI) is the most common cause of brain injury in newborns and the survivors often develop cognitive and sensorimotor disabilities that undermine the quality of life. In the current study, we examined the effectiveness of flupirtine, a potassium channel opener, shown previously in an animal model to have strong anti-neonatal-seizure efficacy, to provide neuroprotection and alleviate later-life disabilities caused by neonatal hypoxic-ischemic injury. METHODS The rats were treated with a single dose of flupirtine for 4 days following HI induction in 7-day-old rats. The first dose of flupirtine was given after the induction of HI and during the reperfusion period. The effect of treatment was examined on acute and chronic brain injury, motor functions, and cognitive abilities. RESULTS Flupirtine treatment significantly reduced HI-induced hippocampal and cortical tissue loss at acute time point. Furthermore, at chronic time point, flupirtine reduced contralateral hippocampal volume loss and partially reversed learning and memory impairments but failed to improve motor deficits. CONCLUSION The flupirtine treatment regimen used in the current study significantly reduced brain injury at acute time point in an animal model of neonatal hypoxic-ischemic encephalopathy. However, these neuroprotective effects were not persistent and only modest improvement in functional outcomes were observed at chronic time points.
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Pospelov AS, Puskarjov M, Kaila K, Voipio J. Endogenous brain-sparing responses in brain pH and PO 2 in a rodent model of birth asphyxia. Acta Physiol (Oxf) 2020; 229:e13467. [PMID: 32174009 DOI: 10.1111/apha.13467] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 12/12/2022]
Abstract
AIM To study brain-sparing physiological responses in a rodent model of birth asphyxia which reproduces the asphyxia-defining systemic hypoxia and hypercapnia. METHODS Steady or intermittent asphyxia was induced for 15-45 minutes in anaesthetized 6- and 11-days old rats and neonatal guinea pigs using gases containing 5% or 9% O2 plus 20% CO2 (in N2 ). Hypoxia and hypercapnia were induced with low O2 and high CO2 respectively. Oxygen partial pressure (PO2 ) and pH were measured with microsensors within the brain and subcutaneous ("body") tissue. Blood lactate was measured after asphyxia. RESULTS Brain and body PO2 fell to apparent zero with little recovery during 5% O2 asphyxia and 5% or 9% O2 hypoxia, and increased more than twofold during 20% CO2 hypercapnia. Unlike body PO2 , brain PO2 recovered rapidly to control after a transient fall (rat), or was slightly higher than control (guinea pig) during 9% O2 asphyxia. Asphyxia (5% O2 ) induced a respiratory acidosis paralleled by a progressive metabolic (lact)acidosis that was much smaller within than outside the brain. Hypoxia (5% O2 ) produced a brain-confined alkalosis. Hypercapnia outlasting asphyxia suppressed pH recovery and prolonged the post-asphyxia PO2 overshoot. All pH changes were accompanied by consistent shifts in the blood-brain barrier potential. CONCLUSION Regardless of brain maturation stage, hypercapnia can restore brain PO2 and protect the brain against metabolic acidosis despite compromised oxygen availability during asphyxia. This effect extends to the recovery phase if normocapnia is restored slowly, and it is absent during hypoxia, demonstrating that exposure to hypoxia does not mimic asphyxia.
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Affiliation(s)
- Alexey S. Pospelov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
| | - Martin Puskarjov
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
| | - Kai Kaila
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
- Neuroscience Center (HiLIFE) University of Helsinki Helsinki Finland
| | - Juha Voipio
- Faculty of Biological and Environmental Sciences, Molecular and Integrative Biosciences University of Helsinki Helsinki Finland
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9
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Wagley PK, Williamson J, Skwarzynska D, Kapur J, Burnsed J. Continuous Video Electroencephalogram during Hypoxia-Ischemia in Neonatal Mice. J Vis Exp 2020. [PMID: 32597865 DOI: 10.3791/61346] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Hypoxia ischemia is the most common cause of neonatal seizures. Animal models are crucial for understanding the mechanisms and physiology underlying neonatal seizures and hypoxia ischemia. This manuscript describes a method for continuous video electroencephalogram (EEG) monitoring in neonatal mice to detect seizures and analyze EEG background during hypoxia ischemia. Use of video and EEG in conjunction allows description of seizure semiology and confirmation of seizures. This method also allows analysis of power spectrograms and EEG background pattern trends over the experimental time period. In this hypoxia ischemia model, the method allows EEG recording prior to injury to obtain a normative baseline and during injury and recovery. Total monitoring time is limited by the inability to separate pups from the mother for longer than four hours. Although, we have used a model of hypoxic-ischemic seizures in this manuscript, this method for neonatal video EEG monitoring could be applied to diverse disease and seizure models in rodents.
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Affiliation(s)
- Pravin K Wagley
- Department of Pediatrics, University of Virginia; Department of Neurology, University of Virginia
| | | | | | - Jaideep Kapur
- Department of Neurology, University of Virginia; Brain Institute, University of Virginia; Department of Neuroscience, University of Virginia
| | - Jennifer Burnsed
- Department of Pediatrics, University of Virginia; Department of Neurology, University of Virginia;
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10
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Abbasi H, Unsworth CP. Electroencephalogram studies of hypoxic ischemia in fetal and neonatal animal models. Neural Regen Res 2020; 15:828-837. [PMID: 31719243 PMCID: PMC6990791 DOI: 10.4103/1673-5374.268892] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alongside clinical achievements, experiments conducted on animal models (including primate or non-primate) have been effective in the understanding of various pathophysiological aspects of perinatal hypoxic/ischemic encephalopathy (HIE). Due to the reasonably fair degree of flexibility with experiments, most of the research around HIE in the literature has been largely concerned with the neurodevelopmental outcome or how the frequency and duration of HI seizures could relate to the severity of perinatal brain injury, following HI insult. This survey concentrates on how EEG experimental studies using asphyxiated animal models (in rodents, piglets, sheep and non-human primate monkeys) provide a unique opportunity to examine from the exact time of HI event to help gain insights into HIE where human studies become difficult.
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Affiliation(s)
- Hamid Abbasi
- Department of Engineering Science, the University of Auckland, Auckland, New Zealand
| | - Charles P Unsworth
- Department of Engineering Science, the University of Auckland, Auckland, New Zealand
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11
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Wu Z, Huo Q, Ren L, Dong F, Feng M, Wang Y, Bai Y, Lüscher B, Li ST, Wang GL, Long C, Wang Y, Wu G, Chen G. Gluconate suppresses seizure activity in developing brains by inhibiting CLC-3 chloride channels. Mol Brain 2019; 12:50. [PMID: 31088565 PMCID: PMC6518791 DOI: 10.1186/s13041-019-0465-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 04/17/2019] [Indexed: 12/03/2022] Open
Abstract
Neonatal seizures are different from adult seizures, and many antiepileptic drugs that are effective in adults often fail to treat neonates. Here, we report that gluconate inhibits neonatal seizure by inhibiting CLC-3 chloride channels. We detect a voltage-dependent outward rectifying Cl− current mediated by CLC-3 Cl− channels in early developing brains but not adult mouse brains. Blocking CLC-3 Cl− channels by gluconate inhibits seizure activity both in neonatal brain slices and in neonatal animals with in vivo EEG recordings. Consistently, neonatal neurons of CLC-3 knockout mice lack the outward rectifying Cl− current and show reduced epileptiform activity upon stimulation. Mechanistically, we demonstrate that activation of CLC-3 Cl− channels alters intracellular Cl− homeostasis and enhances GABA excitatory activity. Our studies suggest that gluconate can suppress neonatal seizure activities through inhibiting CLC-3 Cl− channels in developing brains.
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Affiliation(s)
- Zheng Wu
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Qingwei Huo
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China.,South China Research Center for Acupuncture-Moxibustion, Medical College of Acupuncture-Moxibustion and Rehabilitation, Guangzhou Univ Chinese Med, Guangzhou, 510006, China
| | - Liang Ren
- Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Fengping Dong
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Mengyang Feng
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yue Wang
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Yuting Bai
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Bernhard Lüscher
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Sheng-Tian Li
- Bio-X Institutes, Shanghai Jiao Tong University, 800 Dongchuan Road, Shanghai, 200240, China
| | - Guan-Lei Wang
- Department of Pharmacology, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou, 510080, China
| | - Cheng Long
- School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Yun Wang
- Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Gangyi Wu
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.,School of Life Sciences, South China Normal University, Guangzhou, 510631, China
| | - Gong Chen
- Department of Biology, Huck Institutes of Life Sciences, The Pennsylvania State University, University Park, PA, 16802, USA.
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12
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Abbasi H, Bennet L, Gunn AJ, Unsworth CP. Latent Phase Detection of Hypoxic-Ischemic Spike Transients in the EEG of Preterm Fetal Sheep Using Reverse Biorthogonal Wavelets & Fuzzy Classifier. Int J Neural Syst 2019; 29:1950013. [PMID: 31184228 DOI: 10.1142/s0129065719500138] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Hypoxic-ischemic (HI) studies in preterms lack reliable prognostic biomarkers for diagnostic tests of HI encephalopathy (HIE). Our group's observations from in utero fetal sheep models suggest that potential biomarkers of HIE in the form of developing HI micro-scale epileptiform transients emerge along suppressed EEG/ECoG background during a latent phase of 6-7h post-insult. However, having to observe for the whole of the latent phase disqualifies any chance of clinical intervention. A precise automatic identification of these transients can help for a well-timed diagnosis of the HIE and to stop the spread of the injury before it becomes irreversible. This paper reports fusion of Reverse-Biorthogonal Wavelets with Type-1 Fuzzy classifiers, for the accurate real-time automatic identification and quantification of high-frequency HI spike transients in the latent phase, tested over seven in utero preterm sheep. Considerable high performance of 99.78 ± 0.10% was obtained from the Rbio-Wavelet Type-1 Fuzzy classifier for automatic identification of HI spikes tested over 42h of high-resolution recordings (sampling-freq:1024Hz). Data from post-insult automatic time-localization of high-frequency HI spikes reveals a promising trend in the average rate of the HI spikes, even in the animals with shorter occlusion periods, which highlights considerable higher number of transients within the first 2h post-insult.
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Affiliation(s)
- Hamid Abbasi
- Department of Engineering Science, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Alistair J Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Charles P Unsworth
- Department of Engineering Science, The University of Auckland, Auckland, New Zealand
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13
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Akman O, Raol YH, Auvin S, Cortez MA, Kubova H, de Curtis M, Ikeda A, Dudek FE, Galanopoulou AS. Methodologic recommendations and possible interpretations of video-EEG recordings in immature rodents used as experimental controls: A TASK1-WG2 report of the ILAE/AES Joint Translational Task Force. Epilepsia Open 2018; 3:437-459. [PMID: 30525114 PMCID: PMC6276777 DOI: 10.1002/epi4.12262] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/14/2018] [Indexed: 01/30/2023] Open
Abstract
The use of immature rodents to study physiologic aspects of cortical development requires high‐quality recordings electroencephalography (EEG) with simultaneous video recording (vEEG) of behavior. Normative developmental vEEG data in control animals are fundamental for the study of abnormal background activity in animal models of seizures or other neurologic disorders. Electrical recordings from immature, freely behaving rodents can be particularly difficult because of the small size of immature rodents, their thin and soft skull, interference with the recording apparatus by the dam, and other technical challenges. In this report of the TASK1 Working Group 2 (WG2) of the International League Against Epilepsy/American Epilepsy Society (ILAE/AES) Joint Translational Task Force, we provide suggestions that aim to optimize future vEEG recordings from immature rodents, as well as their interpretation. We focus on recordings from immature rodents younger than 30 days old used as experimental controls, because the quality and correct interpretation of such recordings is important when interpreting the vEEG results of animals serving as models of neurologic disorders. We discuss the technical aspects of such recordings and compare tethered versus wireless approaches. We also summarize the appearance of common artifacts and various patterns of electrical activity seen in young rodents used as controls as a function of behavioral state, age, and (where known) sex and strain. The information herein will hopefully help improve the methodology of vEEG recordings from immature rodents and may lead to results and interpretations that are more consistent across studies from different laboratories.
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Affiliation(s)
- Ozlem Akman
- Department of Physiology Faculty of Medicine Istanbul Bilim University Istanbul Turkey
| | - Yogendra H Raol
- Division of Neurology Department of Pediatrics School of Medicine Translational Epilepsy Research Program University of Colorado Aurora Colorado U.S.A
| | - Stéphane Auvin
- PROTECT, INSERM UMR1141 APHP University Paris Diderot Sorbonne Paris Cité Paris France.,University Hospital Robert-Debré Service of Pediatric Neurology Paris France
| | - Miguel A Cortez
- Department of Pediatrics University of Toronto Toronto Ontario Canada.,Program of Neurosciences and Mental Health Peter Gilgan Center for Research and Learning SickKids Research Institute Toronto Ontario Canada.,Division of Neurology The Hospital for Sick Children Toronto Ontario Canada
| | - Hana Kubova
- Department of Developmental Epileptology Institute of the Czech Academy of Sciences Czech Academy of Sciences Prague Czech Republic
| | - Marco de Curtis
- Epilepsy Unit Carlo Besta Neurological Institute Foundation Milan Italy
| | - Akio Ikeda
- Department of Epilepsy, Movement Disorders, and Physiology Kyoto University Graduate School of Medicine Kyoto Japan
| | - F Edward Dudek
- Department of Neurosurgery University of Utah School of Medicine Salt Lake City Utah U.S.A
| | - Aristea S Galanopoulou
- Laboratory of Developmental Epilepsy Saul R. Korey Department of Neurology Dominick P. Purpura Department of Neuroscience Isabelle Rapin Division of Child Neurology Albert Einstein College of Medicine Einstein/Montefiore Epilepsy Center Montefiore Medical Center Bronx New York U.S.A
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14
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Kasahara Y, Ikegaya Y, Koyama R. Neonatal Seizure Models to Study Epileptogenesis. Front Pharmacol 2018; 9:385. [PMID: 29720941 PMCID: PMC5915831 DOI: 10.3389/fphar.2018.00385] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/04/2018] [Indexed: 12/11/2022] Open
Abstract
Current therapeutic strategies for epilepsy include anti-epileptic drugs and surgical treatments that are mainly focused on the suppression of existing seizures rather than the occurrence of the first spontaneous seizure. These symptomatic treatments help a certain proportion of patients, but these strategies are not intended to clarify the cellular and molecular mechanisms underlying the primary process of epilepsy development, i.e., epileptogenesis. Epileptogenic changes include reorganization of neural and glial circuits, resulting in the formation of an epileptogenic focus. To achieve the goal of developing “anti-epileptogenic” drugs, we need to clarify the step-by-step mechanisms underlying epileptogenesis for patients whose seizures are not controllable with existing “anti-epileptic” drugs. Epileptogenesis has been studied using animal models of neonatal seizures because such models are useful for studying the latent period before the occurrence of spontaneous seizures and the lowering of the seizure threshold. Further, neonatal seizure models are generally easy to handle and can be applied for in vitro studies because cells in the neonatal brain are suitable for culture. Here, we review two animal models of neonatal seizures for studying epileptogenesis and discuss their features, specifically focusing on hypoxia-ischemia (HI)-induced seizures and febrile seizures (FSs). Studying these models will contribute to identifying the potential therapeutic targets and biomarkers of epileptogenesis.
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Affiliation(s)
- Yuka Kasahara
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan
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15
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Nemeth CL, Drummond GT, Mishra MK, Zhang F, Carr P, Garcia MS, Doman S, Fatemi A, Johnston MV, Kannan RM, Kannan S, Wilson MA. Uptake of dendrimer-drug by different cell types in the hippocampus after hypoxic-ischemic insult in neonatal mice: Effects of injury, microglial activation and hypothermia. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2017; 13:2359-2369. [PMID: 28669854 DOI: 10.1016/j.nano.2017.06.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 05/15/2017] [Accepted: 06/22/2017] [Indexed: 12/13/2022]
Abstract
Perinatal hypoxic-ischemic encephalopathy (HIE) can result in neurodevelopmental disability, including cerebral palsy. The only treatment, hypothermia, provides incomplete neuroprotection. Hydroxyl polyamidoamine (PAMAM) dendrimers are being explored for targeted delivery of therapy for HIE. Understanding the biodistribution of dendrimer-conjugated drugs into microglia, neurons and astrocytes after brain injury is essential for optimizing drug delivery. We conjugated N-acetyl-L-cysteine to Cy5-labeled PAMAM dendrimer (Cy5-D-NAC) and used a mouse model of perinatal HIE to study effects of timing of administration, hypothermia, brain injury, and microglial activation on uptake. Dendrimer conjugation delivered therapy most effectively to activated microglia but also targeted some astrocytes and injured neurons. Cy5-D-NAC uptake was correlated with brain injury in all cell types and with activated morphology in microglia. Uptake was not inhibited by hypothermia, except in CD68+ microglia. Thus, dendrimer-conjugated drug delivery can target microglia, astrocytes and neurons and can be used in combination with hypothermia for treatment of HIE.
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Affiliation(s)
- Christina L Nemeth
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, MD 21287, USA
| | - Gabrielle T Drummond
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA
| | - Manoj K Mishra
- Center for Nanomedicine at the Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 N Broadway, Baltimore, MD 21287, USA
| | - Fan Zhang
- Center for Nanomedicine at the Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 N Broadway, Baltimore, MD 21287, USA
| | - Patrice Carr
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA
| | - Maxine S Garcia
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA
| | - Sydney Doman
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA
| | - Ali Fatemi
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, MD 21287, USA
| | - Michael V Johnston
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, MD 21287, USA
| | - Rangaramanujam M Kannan
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA; Center for Nanomedicine at the Wilmer Eye Institute, The Johns Hopkins University School of Medicine, 400 N Broadway, Baltimore, MD 21287, USA
| | - Sujatha Kannan
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA; Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, The Charlotte R. Bloomberg Children's Center, 1800 Orleans Street, Suite 6318D, Baltimore, MD 21287, USA.
| | - Mary Ann Wilson
- Hugo W. Moser Research Institute at Kennedy Krieger, 707 N Broadway, Baltimore, MD 21205, USA; Department of Neurology, The Johns Hopkins University School of Medicine, 1800 Orleans St., Baltimore, MD 21287, USA; Department of Neuroscience, The Johns Hopkins University School of Medicine, 725 N. Wolfe St., Baltimore, MD 21205, USA.
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16
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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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17
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Different response to antiepileptic drugs according to the type of epileptic events in a neonatal ischemia-reperfusion model. Neurobiol Dis 2016; 99:145-153. [PMID: 28042096 DOI: 10.1016/j.nbd.2016.12.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Revised: 12/16/2016] [Accepted: 12/28/2016] [Indexed: 12/23/2022] Open
Abstract
Perinatal arterial stroke is the most frequent form of cerebral infarction in children. Neonatal seizures are the most frequent symptom during the neonatal period. The current management of perinatal stroke is based on supportive care. It is currently unknown if treatment of the seizures modifies the outcome, and no clinical studies have focused on seizures during neonatal stroke. We studied the effect of phenobarbital and levetiracetam on an ischemic-reperfusion stroke model in P7 rats using prolonged electroencephalographic recordings and a histologic analysis of the brain (24h after injury). The following two types of epileptic events were observed: 1) bursts of high amplitude spikes during ischemia and the first hours of reperfusion and 2) organized seizures consisting in discharges of a 1-2Hz spike-and-wave. Both phenobarbital and levetiracetam decreased the total duration of the bursts of high amplitude spikes. Phenobarbital also delayed the start of seizures without changing the total duration of epileptic discharges. The markedly limited efficacy of the antiepileptic drugs studied in our neonatal stroke rat model is frequently observed in human neonatal seizures. Both drugs did not modify the stroke volume, which suggests that the modification of the quantity of bursts of high amplitude spikes does not influence the infarct size. In the absence of a reduction in seizure burden by the antiepileptic drugs, we increased the seizure burden and stroke volume by combining our neonatal stroke model with a lithium-pilocarpine-induced status epilepticus. Our data suggest that the reduction of burst of spikes did not influence the stroke volume. The presence of organized seizure with a pattern close to what is observed in human newborns seems related to the presence of the infarct. Further research is required to determine the relationship between seizure burden and infarct volume.
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18
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Weitzel LR, Sampath D, Shimizu K, White AM, Herson PS, Raol YH. EEG power as a biomarker to predict the outcome after cardiac arrest and cardiopulmonary resuscitation induced global ischemia. Life Sci 2016; 165:21-25. [PMID: 27640888 DOI: 10.1016/j.lfs.2016.09.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 09/12/2016] [Accepted: 09/13/2016] [Indexed: 10/21/2022]
Abstract
AIMS Cardiac arrest (CA) is a major cause of mortality and survivors often develop neurologic deficits. The objective of this study was to determine the effect of CA and cardiopulmonary resuscitation (CPR) in mice on the EEG and neurologic outcomes, and identify biomarkers that can prognosticate poor outcomes. MAIN METHODS Video-EEG records were obtained at various periods following CA-CPR and examined manually to determine the presence of spikes and sharp-waves, and seizures. EEG power was calculated using a fast Fourier transform (FFT) algorithm. KEY FINDINGS Fifty percent mice died within 72h following CA and successful CPR. Universal suppression of the background EEG was observed in all mice following CA-CPR, however, a more severe and sustained reduction in EEG power occurred in the mice that did not survive beyond 72h than those that survived until sacrificed. Spikes and sharp wave activity appeared in the cortex and hippocampus of all mice, but only one out of eight mice developed a purely electrographic seizure in the acute period after CA-CPR. Interestingly, none of the mice that died experienced any acute seizures. At 10days after the CA-CPR, 25% of the mice developed spontaneous convulsive and nonconvulsive seizures that remained restricted to the hippocampus. The frequency of nonconvulsive seizures was higher than that of convulsive seizures. SIGNIFICANCE A strong association between changes in EEG power and mortality following CA-CPR were observed in our study. Therefore, we suggest that the EEG power can be used to prognosticate mortality following CA-CPR induced global ischemia.
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Affiliation(s)
- Lindsay-Rae Weitzel
- Department of Anesthesiology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA
| | - 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
| | - Kaori Shimizu
- Department of Anesthesiology, School of Medicine, 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
| | - Paco S Herson
- Department of Anesthesiology, School of Medicine, University of Colorado, Anschutz Medical Campus, Aurora, CO 80045, USA; Department of Pharmacology, School of Medicine, 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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19
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Huang J, Tang J, Qu Y, Zhang L, Zhou Y, Bao S, Mu D. Mapping the Knowledge Structure of Neonatal Hypoxic-Ischemic Encephalopathy Over the Past Decade: A Co-word Analysis Based on Keywords. J Child Neurol 2016; 31:797-803. [PMID: 26661482 DOI: 10.1177/0883073815615673] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Accepted: 10/08/2015] [Indexed: 12/25/2022]
Abstract
The aim of this study was to analyze the knowledge structure and report the evolution of hypoxic-ischemic encephalopathy research over the past decade based on co-word analysis. Scientific publications focusing on neonatal hypoxic-ischemic encephalopathy were searched from the Web of Science database (January 2005 to December 2014). The keywords from these articles were extracted, and a knowledge network based on these keywords was built using Ucinet6.212 and NetDraw2.084 software. A total of 1892 papers were included, and 39 high-frequency keywords were defined. "HIE" and "neonate" located at the center of the knowledge network. Etiology and pathogenesis, clinical manifestation, and therapy were researched more widely in the network than other aspects of hypoxic-ischemic encephalopathy. This co-word analysis provides an overview of neonatal hypoxic-ischemic encephalopathy research and suggests that the etiology, clinical manifestation, and therapy of hypoxic-ischemic encephalopathy have become research cores over the past decade.
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Affiliation(s)
- Jichong Huang
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
| | - Jun Tang
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
| | - Yi Qu
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
| | - Li Zhang
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
| | - Yan Zhou
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
| | - Shan Bao
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
| | - Dezhi Mu
- Department of Pediatrics, West China Second University Hospital, Sichuan University, Chengdu, China Key Laboratory of Obstetric & Gynecologic and Pediatric Diseases and Birth Defects of Ministry of Education, Sichuan University, Chengdu, China
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20
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Wang J, Wu C, Peng J, Patel N, Huang Y, Gao X, Aljarallah S, Eubanks JH, McDonald R, Zhang L. Early-Onset Convulsive Seizures Induced by Brain Hypoxia-Ischemia in Aging Mice: Effects of Anticonvulsive Treatments. PLoS One 2015; 10:e0144113. [PMID: 26630670 PMCID: PMC4668036 DOI: 10.1371/journal.pone.0144113] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2015] [Accepted: 11/15/2015] [Indexed: 12/27/2022] Open
Abstract
Aging is associated with an increased risk of seizures/epilepsy. Stroke (ischemic or hemorrhagic) and cardiac arrest related brain injury are two major causative factors for seizure development in this patient population. With either etiology, seizures are a poor prognostic factor. In spite of this, the underlying pathophysiology of seizure development is not well understood. In addition, a standardized treatment regimen with anticonvulsants and outcome assessments following treatment has yet to be established for these post-ischemic seizures. Previous studies have modeled post-ischemic seizures in adult rodents, but similar studies in aging/aged animals, a group that mirrors a higher risk elderly population, remain sparse. Our study therefore aimed to investigate early-onset seizures in aging animals using a hypoxia-ischemia (HI) model. Male C57 black mice 18-20-month-old underwent a unilateral occlusion of the common carotid artery followed by a systemic hypoxic episode (8% O2 for 30 min). Early-onset seizures were detected using combined behavioral and electroencephalographic (EEG) monitoring. Brain injury was assessed histologically at different times post HI. Convulsive seizures were observed in 65% of aging mice post-HI but not in control aging mice following either sham surgery or hypoxia alone. These seizures typically occurred within hours of HI and behaviorally consisted of jumping, fast running, barrel-rolling, and/or falling (loss of the righting reflex) with limb spasms. No evident discharges during any convulsive seizures were seen on cortical-hippocampal EEG recordings. Seizure development was closely associated with acute mortality and severe brain injury on brain histological analysis. Intra-peritoneal injections of lorazepam and fosphenytoin suppressed seizures and improved survival but only when applied prior to seizure onset and not after. These findings together suggest that seizures are a major contributing factor to acute mortality in aging mice following severe brain ischemia and that early anticonvulsive treatment may prevent seizure genesis and improve overall outcomes.
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Affiliation(s)
- Justin Wang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Chiping Wu
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Jessie Peng
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Nisarg Patel
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Yayi Huang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Xiaoxing Gao
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Salman Aljarallah
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Neurology Unit, Department of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - James H. Eubanks
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Surgery (Neurosurgery), University of Toronto, Toronto, Ontario, Canada
| | - Robert McDonald
- Department of Neuroscience, University of Lethbridge, Lethbridge, Alberta, Canada
| | - Liang Zhang
- Toronto Western Research Institute, University Health Network, Toronto, Ontario, Canada
- Departments of Medicine (Neurology), University of Toronto, Toronto, Ontario, Canada
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21
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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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22
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Zayachkivsky A, Lehmkuhle MJ, Ekstrand JJ, Dudek FE. Ischemic injury suppresses hypoxia-induced electrographic seizures and the background EEG in a rat model of perinatal hypoxic-ischemic encephalopathy. J Neurophysiol 2015; 114:2753-63. [PMID: 26354320 DOI: 10.1152/jn.00796.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 09/05/2015] [Indexed: 12/16/2022] Open
Abstract
The relationship among neonatal seizures, abnormalities of the electroencephalogram (EEG), brain injury, and long-term neurological outcome (e.g., epilepsy) remains controversial. The effects of hypoxia alone (Ha) and hypoxia-ischemia (HI) were studied in neonatal rats at postnatal day 7; both models generate EEG seizures during the 2-h hypoxia treatment, but only HI causes an infarct with severe neuronal degeneration. Single-channel, differential recordings of acute EEG seizures and background suppression were recorded with a novel miniature telemetry device during the hypoxia treatment and analyzed quantitatively. The waveforms of electrographic seizures (and their behavioral correlates) appeared virtually identical in both models and were identified as discrete events with high power in the traditional delta (0.1-4 Hz) and/or alpha (8-12 Hz) bands. Although the EEG patterns during seizures were similar in Ha- and HI-treated animals at the beginning of the hypoxic insult, Ha caused a more severe electrographic seizure profile than HI near the end. Analyses of power spectral density and seizure frequency profiles indicated that the electrographic seizures progressively increased during the 2-h Ha treatment, while HI led to a progressive decrease in the seizures with significant suppression of the EEG background. These data show that 1) the hypoxia component of these two models drives the seizures; 2) the seizures during Ha are substantially more robust than those during HI, possibly because ongoing neuronal damage blunts the electrographic activity; and 3) a progressive decrease in background EEG, rather than the presence of electrographic seizures, indicates neuronal degeneration during perinatal HI.
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Affiliation(s)
- A Zayachkivsky
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah; and
| | - M J Lehmkuhle
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah; and
| | - J J Ekstrand
- Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, Utah
| | - F E Dudek
- Department of Neurosurgery, University of Utah School of Medicine, Salt Lake City, Utah; and
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23
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Rodriguez-Alvarez N, Jimenez-Mateos EM, Dunleavy M, Waddington JL, Boylan GB, Henshall DC. Effects of hypoxia-induced neonatal seizures on acute hippocampal injury and later-life seizure susceptibility and anxiety-related behavior in mice. Neurobiol Dis 2015; 83:100-14. [PMID: 26341542 DOI: 10.1016/j.nbd.2015.08.023] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 08/06/2015] [Accepted: 08/21/2015] [Indexed: 12/30/2022] Open
Abstract
Seizures are common during the neonatal period, often due to hypoxic-ischemic encephalopathy and may contribute to acute brain injury and the subsequent development of cognitive deficits and childhood epilepsy. Here we explored short- and long-term consequences of neonatal hypoxia-induced seizures in 7 day old C57BL/6J mice. Seizure activity, molecular markers of hypoxia and histological injury were investigated acutely after hypoxia and response to chemoconvulsants and animal behaviour was explored at adulthood. Hypoxia was induced by exposing pups to 5% oxygen for 15 min (global hypoxia). Electrographically defined seizures with behavioral correlates occurred in 95% of these animals and seizures persisted for many minutes after restitution of normoxia. There was minimal morbidity or mortality. Pre- or post-hypoxia injection of phenobarbital (50mg/kg) had limited efficacy at suppressing seizures. The hippocampus from neonatal hypoxia-seizure mice displayed increased expression of vascular endothelial growth factor and the immediate early gene c-fos, minimal histological evidence of cell injury and activation of caspase-3 in scattered neurons. Behavioral analysis of mice five weeks after hypoxia-induced seizures detected novel anxiety-related and other behaviors, while performance in a spatial memory test was similar to controls. Seizure threshold tests with kainic acid at six weeks revealed that mice previously subject to neonatal hypoxia-induced seizures developed earlier, more frequent and longer-duration seizures. This study defines a set of electro-clinical, molecular, pharmacological and behavioral consequences of hypoxia-induced seizures that indicate short- and long-term deleterious outcomes and may be a useful model to investigate the pathophysiology and treatment of neonatal seizures in humans.
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Affiliation(s)
| | - Eva M Jimenez-Mateos
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Mark Dunleavy
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - John L Waddington
- Department of Molecular and Cellular Therapeutics, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Geraldine B Boylan
- Irish Centre for Fetal and Neonatal Translational Research (INFANT), Cork, Ireland
| | - David C Henshall
- Department of Physiology & Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland; Irish Centre for Fetal and Neonatal Translational Research (INFANT), Cork, Ireland.
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24
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Sokoloff MD, Plegue MA, Chervin RD, Barks JD, Shellhaas RA. Phenobarbital and neonatal seizures affect cerebral oxygen metabolism: a near-infrared spectroscopy study. Pediatr Res 2015; 78:91-6. [PMID: 25812123 PMCID: PMC4472490 DOI: 10.1038/pr.2015.64] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 12/22/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND Near-infrared spectroscopy (NIRS) measures oxygen metabolism and is increasingly used for monitoring critically ill neonates. The implications of NIRS-recorded data in this population are poorly understood. We evaluated NIRS monitoring for neonates with seizures. METHODS In neonates monitored with video-electroencephalography, NIRS-measured cerebral regional oxygen saturation (rSO2) and systemic O2 saturation were recorded every 5 s. Mean rSO2 was extracted for 1-h blocks before, during, and after phenobarbital doses. For each electrographic seizure, mean rSO2 was extracted for a period of three times the duration of the seizure before and after the ictal pattern, as well as during the seizure. Linear mixed models were developed to assess the impact of phenobarbital administration and of seizures on rSO2 and fractional tissue oxygen extraction. RESULTS For 20 neonates (estimated gestational age: 39.6 ± 1.5 wk), 61 phenobarbital doses and 40 seizures were analyzed. Cerebral rSO2 rose (P = 0.005), and fractional tissue oxygen extraction declined (P = 0.018) with increasing phenobarbital doses. rSO2 declined during seizures, compared with baseline and postictal phases (baseline 81.2 vs. ictal 77.7 vs. postictal 79.4; P = 0.004). Fractional tissue oxygen extraction was highest during seizures (P = 0.002). CONCLUSIONS Cerebral oxygen metabolism decreases after phenobarbital administration and increases during seizures. These small, but clear, changes in cerebral oxygen metabolism merit assessment for potential clinical impact.
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Affiliation(s)
- Max D. Sokoloff
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, Michigan, USA
| | - Melissa A. Plegue
- Center for Statistical Consultation and Research, University of Michigan, Ann Arbor, Michigan, USA
| | - Ronald D. Chervin
- Department of Neurology, University of Michigan, Ann Arbor, Michigan, USA
| | - John D.E. Barks
- Department of Pediatrics & Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA
| | - Renée A. Shellhaas
- Department of Pediatrics & Communicable Diseases, University of Michigan, Ann Arbor, Michigan, USA,Corresponding Author: Renée Shellhaas, MD, MS, Pediatric Neurology, C.S. Mott Children’s Hospital, room 12-733, 1540 E. Hospital Dr., Ann Arbor, MI, 48109-4279, USA, Telephone: 734-936-4179, Fax: 734-763-7551,
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25
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Effects of neonatal hypoxic-ischemic episodes on late seizure outcomes in C57 black mice. Epilepsy Res 2015; 111:142-9. [PMID: 25769378 DOI: 10.1016/j.eplepsyres.2015.01.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Revised: 01/07/2015] [Accepted: 01/23/2015] [Indexed: 12/17/2022]
Abstract
We examined brain injury and seizures in adult C57 black mice (C57/BL6) that underwent neonatal hypoxic-ischemic (HI) episodes. Mouse pups of 7 days-old underwent a ligation of the right common carotid artery and a subsequent hypoxic challenge (8% O2 for 45min). Post-HI mice were implanted with intracranial electrodes at 2-3 months of age, subjected to behavioral/EEG recordings and hippocampal electrical stimulation in next several months and then euthanized for brain histological assessments at ages of 11-12 months. Histological assessment revealed ipsilateral brain infarctions in 9 post-HI animals. Evident motor seizures were found to occur in only 2 animals with histologically identified cystic infarctions but not in the 21 post-HI animals with or without infarctions. In response to the hippocampal stimulation, post-HI animals were less prone than sham controls to evoked motor seizures. We thus suggest that adult C57 black mice may have low propensity of developing epileptic seizures following the neonatal HI episode. Our present observations may be relevant to future investigation of post-HI epileptogenesis in mouse models.
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Kang SK, Kadam SD. Neonatal Seizures: Impact on Neurodevelopmental Outcomes. Front Pediatr 2015; 3:101. [PMID: 26636052 PMCID: PMC4655485 DOI: 10.3389/fped.2015.00101] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Accepted: 11/05/2015] [Indexed: 11/24/2022] Open
Abstract
Neonatal period is the most vulnerable time for the occurrence of seizures, and neonatal seizures often pose a clinical challenge both for their acute management and frequency of associated long-term co-morbidities. Etiologies of neonatal seizures are known to play a primary role in the anti-epileptic drug responsiveness and the long-term sequelae. Recent studies have suggested that burden of acute recurrent seizures in neonates may also impact chronic outcomes independent of the etiology. However, not many studies, either clinical or pre-clinical, have addressed the long-term outcomes of neonatal seizures in an etiology-specific manner. In this review, we briefly review the available clinical and pre-clinical research for long-term outcomes following neonatal seizures. As the most frequent cause of acquired neonatal seizures, we focus on the studies evaluating long-term effects of HIE-seizures with the goal to evaluate (1) what parameters evaluated during acute stages of neonatal seizures can reliably be used to predict long-term outcomes? and (2) what available clinical and pre-clinical data are available help determine importance of etiology vs. seizure burdens in long-term sequelae.
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Affiliation(s)
- Seok Kyu Kang
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger , Baltimore, MD , USA
| | - Shilpa D Kadam
- Neuroscience Laboratory, Hugo Moser Research Institute at Kennedy Krieger , Baltimore, MD , USA ; Department of Neurology, Johns Hopkins University School of Medicine , Baltimore, MD , USA
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