1
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Hobson BA, Rowland DJ, Dou Y, Saito N, Harmany ZT, Bruun DA, Harvey DJ, Chaudhari AJ, Garbow JR, Lein PJ. A longitudinal MRI and TSPO PET-based investigation of brain region-specific neuroprotection by diazepam versus midazolam following organophosphate-induced seizures. Neuropharmacology 2024; 251:109918. [PMID: 38527652 DOI: 10.1016/j.neuropharm.2024.109918] [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: 11/29/2023] [Revised: 03/01/2024] [Accepted: 03/13/2024] [Indexed: 03/27/2024]
Abstract
Acute poisoning with organophosphorus cholinesterase inhibitors (OPs), such as OP nerve agents and pesticides, can cause life threatening cholinergic crisis and status epilepticus (SE). Survivors often experience significant morbidity, including brain injury, acquired epilepsy, and cognitive deficits. Current medical countermeasures for acute OP poisoning include a benzodiazepine to mitigate seizures. Diazepam was long the benzodiazepine included in autoinjectors used to treat OP-induced seizures, but it is now being replaced in many guidelines by midazolam, which terminates seizures more quickly, particularly when administered intramuscularly. While a direct correlation between seizure duration and the extent of brain injury has been widely reported, there are limited data comparing the neuroprotective efficacy of diazepam versus midazolam following acute OP intoxication. To address this data gap, we used non-invasive imaging techniques to longitudinally quantify neuropathology in a rat model of acute intoxication with the OP diisopropylfluorophosphate (DFP) with and without post-exposure intervention with diazepam or midazolam. Magnetic resonance imaging (MRI) was used to monitor neuropathology and brain atrophy, while positron emission tomography (PET) with a radiotracer targeting translocator protein (TSPO) was utilized to assess neuroinflammation. Animals were scanned at 3, 7, 28, 65, 91, and 168 days post-DFP and imaging metrics were quantitated for the hippocampus, amygdala, piriform cortex, thalamus, cerebral cortex and lateral ventricles. In the DFP-intoxicated rat, neuroinflammation persisted for the duration of the study coincident with progressive atrophy and ongoing tissue remodeling. Benzodiazepines attenuated neuropathology in a region-dependent manner, but neither benzodiazepine was effective in attenuating long-term neuroinflammation as detected by TSPO PET. Diffusion MRI and TSPO PET metrics were highly correlated with seizure severity, and early MRI and PET metrics were positively correlated with long-term brain atrophy. Collectively, these results suggest that anti-seizure therapy alone is insufficient to prevent long-lasting neuroinflammation and tissue remodeling.
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Affiliation(s)
- Brad A Hobson
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA; Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Douglas J Rowland
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Yimeng Dou
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Naomi Saito
- Department of Public Health Sciences, University of California, Davis, School of Medicine, California 95616, USA.
| | - Zachary T Harmany
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA.
| | - Donald A Bruun
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
| | - Danielle J Harvey
- Department of Public Health Sciences, University of California, Davis, School of Medicine, California 95616, USA.
| | - Abhijit J Chaudhari
- Center for Molecular and Genomic Imaging, University of California, Davis, College of Engineering, Davis, CA 95616, USA; Department of Radiology, University of California, Davis, School of Medicine, California 95817, USA.
| | - Joel R Garbow
- Biomedical Magnetic Resonance Center, Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri, 63110, USA.
| | - Pamela J Lein
- Department of Molecular Biosciences, University of California, Davis, School of Veterinary Medicine, Davis, CA 95616, USA.
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2
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Umpierre AD, Li B, Ayasoufi K, Simon WL, Zhao S, Xie M, Thyen G, Hur B, Zheng J, Liang Y, Bosco DB, Maynes MA, Wu Z, Yu X, Sung J, Johnson AJ, Li Y, Wu LJ. Microglial P2Y 6 calcium signaling promotes phagocytosis and shapes neuroimmune responses in epileptogenesis. Neuron 2024:S0896-6273(24)00195-8. [PMID: 38614103 DOI: 10.1016/j.neuron.2024.03.017] [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: 06/29/2023] [Revised: 01/09/2024] [Accepted: 03/13/2024] [Indexed: 04/15/2024]
Abstract
Microglial calcium signaling is rare in a baseline state but strongly engaged during early epilepsy development. The mechanism(s) governing microglial calcium signaling are not known. By developing an in vivo uridine diphosphate (UDP) fluorescent sensor, GRABUDP1.0, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP can signal through the microglial-enriched P2Y6 receptor to increase calcium activity during epileptogenesis. P2Y6 calcium activity is associated with lysosome biogenesis and enhanced production of NF-κB-related cytokines. In the hippocampus, knockout of the P2Y6 receptor prevents microglia from fully engulfing neurons. Attenuating microglial calcium signaling through calcium extruder ("CalEx") expression recapitulates multiple features of P2Y6 knockout, including reduced lysosome biogenesis and phagocytic interactions. Ultimately, P2Y6 knockout mice retain more CA3 neurons and better cognitive task performance during epileptogenesis. Our results demonstrate that P2Y6 signaling impacts multiple aspects of myeloid cell immune function during epileptogenesis.
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Affiliation(s)
| | - Bohan Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China
| | | | - Whitney L Simon
- Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| | - Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| | - Manling Xie
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Grace Thyen
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Benjamin Hur
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yue Liang
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Dale B Bosco
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA
| | - Mark A Maynes
- Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905, USA
| | - Zhaofa Wu
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China
| | - Xinzhu Yu
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Jaeyun Sung
- Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905, USA; Department of Surgery, Mayo Clinic, Rochester, MN 55905, USA
| | - Aaron J Johnson
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA
| | - Yulong Li
- State Key Laboratory of Membrane Biology, Peking University School of Life Sciences, Beijing 100871, China.
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905, USA; Department of Immunology, Mayo Clinic, Rochester, MN 55905, USA; Center for Neuroimmunology and Glial Biology, Institute of Molecular Medicine, University of Texas Health Science Center, Houston, TX 77030, USA.
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3
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Liachenko S, Ramu J, Paule MG, Hanig J. Performance of the prospective T 2 MRI biomarker of neurotoxicity in a trimethyltin model in rats at 7 T. Neurotoxicol Teratol 2023; 100:107289. [PMID: 37689269 DOI: 10.1016/j.ntt.2023.107289] [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: 04/17/2023] [Revised: 08/29/2023] [Accepted: 08/29/2023] [Indexed: 09/11/2023]
Abstract
The assessment of the sensitivity and specificity of any potential biomarker against the gold standard is an important step in the process of its qualification by regulatory authorities. Such qualification is an important step towards incorporating the biomarker into the panel of tools available for drug development. In the current study we analyzed the sensitivity and specificity of T2 MRI relaxometry to detect trimethyltin-induced neurotoxicity in rats. Seventy-five male Sprague-Dawley rats were injected with a single intraperitoneal dose of either TMT (8, 10, 11, or 12 mg/kg) or saline (2 ml/kg) and imaged with 7 T MRI before and 3, 7, 14, and 21 days after injection using a quantitative T2 mapping. Neurohistopathology (the gold standard in the case of neurotoxicity) was performed at the end of the observation and used as an outcome qualifier in receiver-operator characteristic (ROC) curve analysis of T2 changes as a predictor of neurotoxicity. TMT treatment led to a significant increase in T2 values in many brain areas. The biggest changes in T2 values were seen around the lateral ventricles, which was interpreted as ventricular dilation. The area under the ROC curve for the volume of the lateral ventricles was 0.878 with the optimal sensitivity/specificity of 0.805/0.933, respectively. T2 MRI is a promising method for generating a non-invasive biomarkers of neurotoxicity, which shows the dose-response behavior with substantial sensitivity and specificity. While its performance was strong in the TMT model, further characterization of the sensitivity and specificity of T2 MRI with other neurotoxicants is warranted.
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Affiliation(s)
- Serguei Liachenko
- Division of Neurotoxicology, NCTR, US FDA, Jefferson, AR, United States of America.
| | - Jaivijay Ramu
- Division of Neurotoxicology, NCTR, US FDA, Jefferson, AR, United States of America
| | - Merle G Paule
- Division of Neurotoxicology, NCTR, US FDA, Jefferson, AR, United States of America
| | - Joseph Hanig
- Office of Pharmaceutical Quality, CDER, US FDA, White Oak, MD, United States of America
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4
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Umpierre AD, Li B, Ayasoufi K, Zhao S, Xie M, Thyen G, Hur B, Zheng J, Liang Y, Wu Z, Yu X, Sung J, Johnson AJ, Li Y, Wu LJ. Microglial P2Y 6 calcium signaling promotes phagocytosis and shapes neuroimmune responses in epileptogenesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.12.544691. [PMID: 37398001 PMCID: PMC10312639 DOI: 10.1101/2023.06.12.544691] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Microglial calcium signaling is rare in a baseline state but shows strong engagement during early epilepsy development. The mechanism and purpose behind microglial calcium signaling is not known. By developing an in vivo UDP fluorescent sensor, GRABUDP1.0, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP signals to the microglial P2Y6 receptor for broad increases in calcium signaling during epileptogenesis. UDP-P2Y6 signaling is necessary for lysosome upregulation across limbic brain regions and enhances production of pro-inflammatory cytokines-TNFα and IL-1β. Failures in lysosome upregulation, observed in P2Y6 KO mice, can also be phenocopied by attenuating microglial calcium signaling in Calcium Extruder ("CalEx") mice. In the hippocampus, only microglia with P2Y6 expression can perform full neuronal engulfment, which substantially reduces CA3 neuron survival and impairs cognition. Our results demonstrate that calcium activity, driven by UDP-P2Y6 signaling, is a signature of phagocytic and pro-inflammatory function in microglia during epileptogenesis.
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Affiliation(s)
- Anthony D. Umpierre
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- These authors contributed equally
| | - Bohan Li
- State Key Laboratory of Membrane Biology, New Cornerstone Science Laboratory, Peking University School of Life Sciences, Beijing, CN 100871
- These authors contributed equally
| | | | - Shunyi Zhao
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Neuroscience Track, Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905
| | - Manling Xie
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Neuroscience Track, Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905
| | - Grace Thyen
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
| | - Benjamin Hur
- Microbiome Program, Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905
- Division of Surgery Research, Department of Surgery, Mayo Clinic, Rochester, MN 55905
| | - Jiaying Zheng
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Neuroscience Track, Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN 55905
| | - Yue Liang
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
| | - Zhaofa Wu
- State Key Laboratory of Membrane Biology, New Cornerstone Science Laboratory, Peking University School of Life Sciences, Beijing, CN 100871
| | - Xinzhu Yu
- Department of Molecular and Integrative Physiology, Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL 61801
| | - Jaeyun Sung
- Microbiome Program, Center for Individualized Medicine, Mayo Clinic, Rochester, MN 55905
- Division of Surgery Research, Department of Surgery, Mayo Clinic, Rochester, MN 55905
| | - Aaron J. Johnson
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
- Department of Molecular Medicine, Mayo Clinic, Rochester MN 55905
| | - Yulong Li
- State Key Laboratory of Membrane Biology, New Cornerstone Science Laboratory, Peking University School of Life Sciences, Beijing, CN 100871
| | - Long-Jun Wu
- Department of Neurology, Mayo Clinic, Rochester, MN 55905
- Department of Immunology, Mayo Clinic, Rochester, MN 55905
- Lead contact
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5
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Xu K, Xie P, Deng J, Tang C, Wang X, Guan Y, Zhou J, Li T, Liang X, Jing B, Gao JH, Luan G. Long-term ANT-DBS effects in pilocarpine-induced epileptic rats: A combined 9.4T MRI and histological study. J Neurosci Res 2023; 101:916-929. [PMID: 36696411 DOI: 10.1002/jnr.25169] [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: 08/23/2022] [Revised: 01/02/2023] [Accepted: 01/09/2023] [Indexed: 01/26/2023]
Abstract
Deep brain stimulation (DBS) of the anterior nucleus of the thalamus (ANT) appears to be effective against seizures in animals and humans however, its therapeutic mechanisms remain elusive. This study aimed to combine 9.4T multimodal magnetic resonance imaging (MRI) with histology to investigate the longitudinal effects of long-term ANT-DBS in pilocarpine-induced epileptic rats. Status epilepsy (SE) was induced by LiCl-pilocarpine injection in 11 adult male Sprague-Dawley rats. Four weeks after SE, chronic epileptic rats underwent either ANT-DBS (n = 6) or sham-DBS (n = 5) surgery. Electroencephalography (EEG) and spontaneous recurrent seizures (SRS) were recorded for 1 week. The T2-weighted image and images from resting-state functional MRI (rs-fMRI) were acquired at three states: before SE, at 4 weeks post-SE, and at 5 weeks post-DBS. Volumes of the hippocampal subregions and hippocampal-related functional connectivity (FC) were compared longitudinally. Finally, antibodies against neuronal nuclei (NeuN) and glial fibrillary acidic proteins were used to evaluate neuronal loss and astrogliosis in the hippocampus. Long-term ANT-DBS significantly reduced seizure generalization in pilocarpine-induced epileptic rats. By analyzing the gray matter volume using T2-weighted images, long-term ANT-DBS displayed morphometric restoration of the hippocampal subregions. Neuronal protection of the hippocampal subregions and inhibition of astrogliosis in the hippocampal subregions were observed in the ANT-DBS group. ANT-DBS caused reversible regulation of FC in the insula-hippocampus and subthalamic nucleus-hippocampus. Long-term ANT-DBS provides comprehensive protection of hippocampal histology, hippocampal morphometrics, and hippocampal-related functional networks.
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Affiliation(s)
- Ke Xu
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Pandeng Xie
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Jiahui Deng
- Beijing Key Laboratory of Epilepsy Research, Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
| | - Chongyang Tang
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Xiongfei Wang
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Yuguang Guan
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Jian Zhou
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Tianfu Li
- Beijing Key Laboratory of Epilepsy Research, Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
- Key Laboratory of Epilepsy, Department of Neurology, Center of Epilepsy, Beijing Institute for Brain Disorders, SanBo Brain Hospital, Capital Medical University, Beijing, China
| | - Xiaohang Liang
- Beijing City Key Laboratory for Medical Physics and Engineering, Institution of Heavy Ion Physics, School of Physics, Peking University, Beijing, China
- Center for MRI Research, Peking University, Beijing, China
| | - Bin Jing
- School of Biomedical Engineering, Capital Medical University, Beijing, China
| | - Jia-Hong Gao
- Beijing City Key Laboratory for Medical Physics and Engineering, Institution of Heavy Ion Physics, School of Physics, Peking University, Beijing, China
- Center for MRI Research, Peking University, Beijing, China
| | - Guoming Luan
- Department of Neurosurgery, SanBo Brain Hospital, Capital Medical University, Beijing, China
- Beijing Key Laboratory of Epilepsy Research, Department of Brain Institute, Center of Epilepsy, Beijing Institute for Brain Disorders, Sanbo Brain Hospital, Capital Medical University, Beijing, China
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6
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Fernandez AM, Gutekunst CA, Grogan DP, Pedersen NP, Gross RE. Loss of efferent projections of the hippocampal formation in the mouse intrahippocampal kainic acid model. Epilepsy Res 2022; 180:106863. [DOI: 10.1016/j.eplepsyres.2022.106863] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 12/15/2021] [Accepted: 01/17/2022] [Indexed: 11/16/2022]
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7
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Wagner MW, Skocic J, Widjaja E. Seizure control does not predict hippocampal subfield volume change in children with focal drug-resistant epilepsy. Neuroradiol J 2021; 35:454-460. [PMID: 34618625 PMCID: PMC9437498 DOI: 10.1177/19714009211049078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Background and purpose Recurrent seizures have been reported to induce neuronal loss in the
hippocampus. It is unclear whether seizure control influences hippocampal
volume. The aims of this study were to determine if there was a change in
total or subfield hippocampal volume over time in children with focal
drug-resistant epilepsy, and whether seizure control influenced total or
subfield hippocampal volumes. Methods Using FreeSurfer’s automated segmentation of brain magnetic resonance imaging
scans, we calculated the total and subfield (including CA1, CA3, CA4,
subiculum, presubiculum, parasubiculum, molecular layer and dentate gyrus)
hippocampal volumes of children with non-lesional focal epilepsy. Seizure
frequency and hippocampal volumes were assessed at baseline and follow-up.
Patients were classified into those who were seizure free or have
improvement in seizures (group 1) and those with no improvement in seizures
(group 2) at follow-up. Results Thirty-seven patients were included, with mean age 10.31 ± 3.68 years at
baseline. The interval between the two magnetic resonance imaging scans was
2.59 ± 1.25 years. There was no significant difference in the total and
subfield hippocampal volumes for the whole cohort at follow-up compared to
baseline (all P > 0.002). Seizure control of the two
groups did not predict total or subfield hippocampal volume, after
controlling for baseline volume, age, severity of seizure frequency at
baseline and time interval between the magnetic resonance imaging scans (all
P > 0.002). Conclusion We have found that total and subfield hippocampal volumes did not change, and
seizure control did not predict hippocampal volumes at follow-up in children
with drug-resistant epilepsy.
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Affiliation(s)
- Matthias W Wagner
- Department of Diagnostic Imaging, The Hospital for Sick Children, Canada
| | - Jovanka Skocic
- Department of Diagnostic Imaging, The Hospital for Sick Children, Canada
| | - Elysa Widjaja
- Department of Diagnostic Imaging, The Hospital for Sick Children, Canada
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8
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An inventory of basic research in temporal lobe epilepsy. Rev Neurol (Paris) 2021; 177:1069-1081. [PMID: 34176659 DOI: 10.1016/j.neurol.2021.02.390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Revised: 01/26/2021] [Accepted: 02/05/2021] [Indexed: 12/25/2022]
Abstract
Temporal lobe epilepsy is a severe neurological disease, characterized by seizure occurrence and invalidating cognitive co-morbidities, which affects up to 1% of the adults. Roughly one third of the patients are resistant to any conventional pharmacological treatments. The last option in that case is the surgical removal of the epileptic focus, with no guarantee for clinical symptom alleviation. This state of affairs requests the identification of cellular or molecular targets for novel therapeutic approaches with limited side effects. Here we review some generalities about the disease as well as some of the most recent discoveries about the cellular and molecular mechanisms of TLE, and the latest perspectives for novel treatments.
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9
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Salaka RJ, Nair KP, Annamalai K, Srikumar BN, Kutty BM, Shankaranarayana Rao BS. Enriched environment ameliorates chronic temporal lobe epilepsy-induced behavioral hyperexcitability and restores synaptic plasticity in CA3-CA1 synapses in male Wistar rats. J Neurosci Res 2021; 99:1646-1665. [PMID: 33713475 DOI: 10.1002/jnr.24823] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 02/06/2021] [Accepted: 02/17/2021] [Indexed: 01/11/2023]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsies. Pharmacoresistance and comorbidities pose significant challenges to its treatment necessitating the development of non-pharmacological approaches. In an earlier study, exposure to enriched environment (EE) reduced seizure frequency and duration and ameliorated chronic epilepsy-induced depression in rats. However, the cellular basis of beneficial effects of EE remains unknown. Accordingly, in the current study, we evaluated the effects of EE in chronic epilepsy-induced changes in behavioral hyperexcitability, synaptic transmission, synaptophysin (SYN), and calbindin (CB) expression, hippocampal subfield volumes and cell density in male Wistar rats. Epilepsy was induced by lithium-pilocarpine-induced status epilepticus. Chronic epilepsy resulted in behavioral hyperexcitability, decreased basal synaptic transmission, increased paired-pulse facilitation ratio, decreased hippocampal subfields volumes. Moreover, epileptic rats showed decreased synaptophysin and CB expression in the hippocampus. Six weeks post-SE, epileptic rats were exposed to EE for 2 weeks, 6 hr/day. EE significantly reduced the behavioral hyperexcitability and restored basal synaptic transmission correlating with increased expression of SYN and CB. Our results reaffirm the beneficial effects of EE on behavior in chronic epilepsy and establishes some of the putative cellular mechanisms. Since drug resistance and comorbidities are a major concern in TLE, we propose EE as a potent non-pharmacological treatment modality to mitigate these changes in chronic epilepsy.
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Affiliation(s)
- Raghava Jagadeesh Salaka
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Kala P Nair
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Kiruthiga Annamalai
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Bettadapura N Srikumar
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
| | - Bindu M Kutty
- Department of Neurophysiology, National Institute of Mental Health and Neuro Sciences, Bengaluru, India
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10
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Setkowicz Z, Kiełbinski M, Gzieło K, Węglarz W, Janeczko K. Changes of EEG spectra in rat brains with different patterns of dysplasia in response to pilocarpine-induced seizures. Epilepsy Behav 2020; 111:107288. [PMID: 32702654 DOI: 10.1016/j.yebeh.2020.107288] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 06/20/2020] [Accepted: 06/24/2020] [Indexed: 12/14/2022]
Abstract
Disorders of neurogenesis at early developmental stages lead to irreversible structural and functional impairments of the brain. As further their consequences, increases in brain excitability and the development of drug-resistant epilepsy can frequently be observed in clinical cases. Mechanisms underlying these phenomena can also be examined on animal models of brain dysplasia. This study was conducted on rats with four degrees of brain dysplasia following exposure to gamma radiation on days 13, 15, 17, or 19 of prenatal development. When reached adulthood, the rats received electroencephalographic (EEG) transmitter implantation. Thereafter, pilocarpine was administered, and significant differences in susceptibility to seizures were detected depending on the degree of brain dysplasia. Before, during, and after the seizures, EEG was recorded in free moving animals. Additionally, the intensity of seizure behavioral symptoms was assessed. Strong and moderate correlations were found between the intensity of seizure behavioral symptoms, the power of particular EEG bands, and volumes of dysplastic brains and their regions. The data drew particular attention to correlations between variations in EEG spectra and changes in the midbrain and pons volumes. The results point to possible significant roles of these regions in the observed changes of susceptibility to seizures. Consequently, the frequently used experimental model was considered here not only as representing cases of cortical dysplasia but also of generalized, diffuse dysplasia of the whole brain.
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Affiliation(s)
- Zuzanna Setkowicz
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Michał Kiełbinski
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Kinga Gzieło
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland
| | - Władysław Węglarz
- Department of Magnetic Resonance Imaging, Institute of Nuclear Physics, Polish Academy of Sciences, Krakow, Poland
| | - Krzysztof Janeczko
- Department of Neuroanatomy, Institute of Zoology and Biomedical Research, Jagiellonian University, Krakow, Poland.
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11
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Andoh M, Ikegaya Y, Koyama R. Microglia modulate the structure and function of the hippocampus after early-life seizures. J Pharmacol Sci 2020; 144:212-217. [PMID: 33070840 DOI: 10.1016/j.jphs.2020.09.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 08/19/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023] Open
Abstract
The hippocampus is a brain region well-known to exhibit structural and functional changes in temporal lobe epilepsy. Studies analyzing the brains of patients with epilepsy and those from animal models of epilepsy have revealed that microglia are excessively activated, especially in the hippocampus. These findings suggest that microglia may contribute to the onset and aggravation of epilepsy; however, direct evidence for microglial involvement or the underlying mechanisms by which this occurs remain to be fully discovered. To date, neuron-microglia interactions have been vigorously studied in adult epilepsy models; such studies have clarified microglial responses to excessive synchronous firing of neurons. In contrast, the role of microglia in the postnatal brain of patients with epileptic seizures remain largely unclear. Some early-life seizures, such as complex febrile seizures, have been shown to cause structural and functional changes in the brain, which is a risk factor for future development of epilepsy. Because brain structure and function are actively modulated by microglia in both health and disease, it is essential to clarify the role of microglia in early-life seizures and its impact on epileptogenesis.
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Affiliation(s)
- Megumi Andoh
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Yuji Ikegaya
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan
| | - Ryuta Koyama
- Laboratory of Chemical Pharmacology, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Bunkyo-ku, Tokyo, Japan.
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12
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Nobili P, Cattalini A, de Grazia U, Cagnoli C, de Curtis M, Battaglia GS, Colciaghi F. Early Chronic Carbamazepine-in-Food Administration to MAM/Pilocarpine Rats Does Not Affect Convulsive Motor Seizures. Front Pharmacol 2020; 11:181. [PMID: 32180728 PMCID: PMC7059791 DOI: 10.3389/fphar.2020.00181] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 02/10/2020] [Indexed: 11/21/2022] Open
Abstract
Antiepileptic drug-resistance is a major health problem in patients with cortical dysplasia (CD). Whether drug-resistant epilepsy is associated with progressive brain damage is still debated. We previously generated a rat model of acquired CD, the methylazoxymethanol-pilocarpine (MP) rat, in which the occurrence of status epilepticus and subsequent spontaneous seizures induce progressive brain damage (Nobili et al., 2015). The present study tested the outcome of early-chronic carbamazepine (CBZ) administration on both seizure activity and brain damage in MP rats. We took advantage of the non-invasive CBZ-in-food administration protocol, established by Ali (2012), which proved effective in suppressing generalized convulsive seizures in kainic acid rat model of epilepsy. MP rats were treated immediately after the onset of the first spontaneous seizure with 300 mg/kg/day CBZ formulated in pellets for a two-months-trial. CBZ-treated rats were continuously video-monitored to detect seizure activity and were compared with untreated epileptic MP rats. Despite CBZ serum levels in treated rats were within the suggested therapeutic range for humans, CBZ affected spontaneous convulsive seizures in 2 out of 10 treated rats (responders), whereas the remaining animals (non-responders) did not show any difference when compared to untreated MP rats. Histological analysis revealed cortical thinning paralleled by robust staining of Fluoro-Jade+ (FJ+) degenerating neurons and diffuse tissue necrosis in CBZ-non-responder vs CBZ-responder rats. Data reported here suggest that MP rat model represents suitable experimental setting where to investigate mechanisms of CD-related drug-resistant epilepsy and to verify if modulation of seizures, with appropriate treatment, may reduce seizure-induced brain damage.
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Affiliation(s)
- Paola Nobili
- Clinical and Experimental Epileptology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Alessandro Cattalini
- Clinical and Experimental Epileptology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Ugo de Grazia
- Laboratory of Neurological Biochemistry and Neuropharmacology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Cinzia Cagnoli
- Clinical and Experimental Epileptology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Marco de Curtis
- Clinical and Experimental Epileptology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Giorgio Stefano Battaglia
- Clinical and Experimental Epileptology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
| | - Francesca Colciaghi
- Clinical and Experimental Epileptology Unit, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milano, Italy
- *Correspondence: Francesca Colciaghi,
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13
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Alterations in the functional brain network in a rat model of epileptogenesis: A longitudinal resting state fMRI study. Neuroimage 2019; 202:116144. [PMID: 31473355 DOI: 10.1016/j.neuroimage.2019.116144] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 08/13/2019] [Accepted: 08/28/2019] [Indexed: 11/21/2022] Open
Abstract
Epilepsy is a neurological disorder characterized by recurrent epileptic seizures. Electrophysiological and neuroimaging studies in patients with epilepsy suggest that abnormal functional brain networks play a role in the development of epilepsy, i.e. epileptogenesis, resulting in the generation of spontaneous seizures and cognitive impairment. In this longitudinal study, we investigated changes in functional brain networks during epileptogenesis in the intraperitoneal kainic acid (IPKA) rat model of temporal lobe epilepsy (TLE) using resting state functional magnetic resonance imaging (rsfMRI) and graph theory. Additionally, we investigated whether these changes are related to the frequency of occurrence of spontaneous epileptic seizures in the chronic phase of epilepsy. Using a 7T MRI system, rsfMRI images were acquired under medetomidine anaesthesia before and 1, 3, 6, 10 and 16 weeks after status epilepticus (SE) induction in 20 IPKA animals and 7 healthy control animals. To obtain a functional network, correlation between fMRI time series of 38 regions of interest (ROIs) was calculated. Then, several graph theoretical network measures were calculated to describe and quantify the network changes. At least 17 weeks post-SE, IPKA animals were implanted with electrodes in the left and right dorsal hippocampus, EEG was measured for 7 consecutive days and spontaneous seizures were counted. Our results show that correlation coefficients of fMRI time series shift to lower values during epileptogenesis, indicating weaker whole brain network connections. Segregation and integration in the functional brain network also decrease, indicating a lower local interconnectivity and a lower overall communication efficiency. Secondly, this study demonstrates that the largest decrease in functional connectivity is observed for the retrosplenial cortex. Finally, post-SE changes in functional connectivity, segregation and integration are correlated with seizure frequency in the IPKA rat model.
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14
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Cavarsan CF, Malheiros J, Hamani C, Najm I, Covolan L. Is Mossy Fiber Sprouting a Potential Therapeutic Target for Epilepsy? Front Neurol 2018; 9:1023. [PMID: 30555406 PMCID: PMC6284045 DOI: 10.3389/fneur.2018.01023] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022] Open
Abstract
Mesial temporal lobe epilepsy (MTLE) caused by hippocampal sclerosis is one of the most frequent focal epilepsies in adults. It is characterized by focal seizures that begin in the hippocampus, sometimes spread to the insulo-perisylvian regions and may progress to secondary generalized seizures. Morphological alterations in hippocampal sclerosis are well defined. Among them, hippocampal sclerosis is characterized by prominent cell loss in the hilus and CA1, and abnormal mossy fiber sprouting (granular cell axons) into the dentate gyrus inner molecular layer. In this review, we highlight the role of mossy fiber sprouting in seizure generation and hippocampal excitability and discuss the response of alternative treatment strategies in terms of MFS and spontaneous recurrent seizures in models of TLE (temporal lobe epilepsy).
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Affiliation(s)
- Clarissa F Cavarsan
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Jackeline Malheiros
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil
| | - Clement Hamani
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.,Harquail Centre for Neuromodulation, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, ON, Canada
| | - Imad Najm
- Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
| | - Luciene Covolan
- Department of Physiology, Universidade Federal de São Paulo, São Paulo, Brazil.,Epilepsy Center, Neurological Institute, Cleveland Clinic, Cleveland, OH, United States
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15
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Bajorat R, Porath K, Kuhn J, Goßla E, Goerss D, Sellmann T, Köhling R, Kirschstein T. Oral administration of the casein kinase 2 inhibitor TBB leads to persistent K Ca2.2 channel up-regulation in the epileptic CA1 area and cortex, but lacks anti-seizure efficacy in the pilocarpine epilepsy model. Epilepsy Res 2018; 147:42-50. [PMID: 30219695 DOI: 10.1016/j.eplepsyres.2018.08.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Revised: 07/31/2018] [Accepted: 08/29/2018] [Indexed: 02/04/2023]
Abstract
Temporal lobe epilepsy (TLE) is the most common epileptic syndrome in adults and often presents with seizures that prove intractable with currently available anticonvulsants. Thus, there is still a need for new anti-seizure drugs in this condition. Recently, we found that the casein kinase 2 inhibitor 4,5,6,7-tetrabromotriazole (TBB) prevented the emergence of spontaneous epileptic discharges in an acute in vitro epilepsy model. This prompted us to study the anti-seizure effects of TBB in the pilocarpine model of chronic epilepsy in vivo. To this end, we performed long-term video-EEG monitoring lasting 78-167 days of nine chronically epileptic rats and obtained a baseline seizure rate of 3.3 ± 1.3 per day (baseline of 27-80 days). We found a significant age effect with more pronounced seizure rates in older animals as compared to younger ones. However, the seizure rate increased to 6.3 ± 2.2 per day during the oral TBB administration (treatment period of 21-50 days), and following discontinuation of TBB, this rate remained stable with 5.2 ± 1.4 seizures per day (follow-up of 30-55 days). After completing the video-EEG during the follow-up the hippocampal tissue was prepared and studied for the expression of the Ca2+-activated K+ channel KCa2.2. We found a significant up-regulation of KCa2.2 in the epileptic CA1 region and in the neocortex, but in no other hippocampal subfield. Hence, our findings indicate that oral administration of TBB leads to persistent up-regulation of KCa2.2 in the epileptic CA1 subfield and in the neocortex, but lacks anti-seizure efficacy in the pilocarpine epilepsy model.
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Affiliation(s)
- Rika Bajorat
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany; Department of Anesthesiology and Intensive Care Medicine, Rostock University Medical Centre, Rostock, Germany.
| | - Katrin Porath
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany.
| | - Johannes Kuhn
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany.
| | - Elke Goßla
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany.
| | - Doreen Goerss
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany; Department of Psychosomatic and Psychotherapeutic Medicine, Rostock University Medical Centre, Rostock, Germany.
| | - Tina Sellmann
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany.
| | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany.
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, Rostock University Medical Centre, Rostock, Germany.
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16
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Volumetric response of the adult brain to seizures depends on the developmental stage when systemic inflammation was induced. Epilepsy Behav 2018; 78:280-287. [PMID: 29128467 DOI: 10.1016/j.yebeh.2017.09.009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 09/15/2017] [Accepted: 09/15/2017] [Indexed: 01/07/2023]
Abstract
Inflammation has detrimental influences on the developing brain including triggering the epileptogenesis. On the other hand, seizure episodes may induce inflammatory processes and further increase of brain excitability. The present study focuses on the problem whether transitory systemic inflammation during developmental period may have critical importance to functional and/or structural features of the adult brain. An inflammatory status was induced with lipopolysaccharide (LPS) in 6- or 30-day-old rats. Two-month-old rats which experienced the inflammation and untreated controls received injections of pilocarpine, and the intensity of their seizure behavior was rated during a 6-hour period. Three days thereafter, the animals were perfused; their brains were postfixed and subjected to magnetic resonance imaging (MRI) scans. Then, volumes of the brain and of its main regions were assessed. LPS injections alone performed at different developmental stages led to different changes in the volume of adult brain and also to different susceptibility to seizures induced in adulthood. Moreover, the LPS pretreatments modified different volumetric responses of the brain and of its regions to seizures. The responses showed strong inverse correlations with the intensity of seizures but exclusively in rats treated with LPS on postnatal day 30. It could be concluded that generalized inflammation elicited at developmental stages may have strong age-dependent effects on the adult brain regarding not only its susceptibility to action of a seizuregenic agent but also its volumetric reactivity to seizures.
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17
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Ferreira ES, Vieira LG, Moraes DM, Amorim BO, Malheiros JM, Hamani C, Covolan L. Long-Term Effects of Anterior Thalamic Nucleus Deep Brain Stimulation on Spatial Learning in the Pilocarpine Model of Temporal Lobe Epilepsy. Neuromodulation 2017; 21:160-167. [PMID: 28960670 DOI: 10.1111/ner.12688] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/29/2017] [Accepted: 07/25/2017] [Indexed: 01/20/2023]
Abstract
INTRODUCTION AND OBJECTIVES Cognitive impairment is a significant comorbidity of temporal lobe epilepsy that is associated with extensive hippocampal cell loss. Deep brain stimulation (DBS) of the anterior thalamic nucleus (ANT) has been used for the treatment of refractory partial seizures. In the pilocarpine model of epilepsy, ANT DBS applied during status epilepticus (SE) reduces hippocampal inflammation and apoptosis. When given to chronic epileptic animals it reduces hippocampal excitability and seizure frequency. Here, we tested whether ANT DBS delivered during SE and the silent phase of the pilocarpine model would reduce cognitive impairment when animals became chronically epileptic. MATERIALS AND METHODS SE was induced by a systemic pilocarpine injection (320 mg/kg). Immediately after SE onset, rats were assigned to receive DBS during the first six hours of SE (n = 8; DBSa group) or during SE + the silent period (i.e., 6 h/day until the animals developed the first spontaneous recurrent seizure; n = 10; DBSs group). Four months following SE, animals underwent water maze testing and histological evaluation. Nonstimulated chronic epileptic animals (n = 13; PCTL group) and age-matched naïve rats (n = 11, CTL group) were used as controls. Results were analyzed by repeated-measures analyses of variance (RM_ANOVA) and one-way ANOVAs, followed by Newman-Keuls post hoc tests. RESULTS Although all groups learned the spatial task, epileptic animals with or without DBS spent significantly less time in the platform quadrant, denoting a spatial memory deficit (p < 0.02). Despite these negative behavioral results, we found that animals given DBS had a significantly higher number of cells in the CA1 region and dentate gyrus. Mossy fiber sprouting was similar among all epileptic groups. CONCLUSIONS Despite lesser hippocampal neuronal loss, ANT DBS delivered either during SE or during SE and the silent phase of the pilocarpine model did not mitigate memory deficits in chronic epileptic rats.
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Affiliation(s)
- Elenn Soares Ferreira
- Department of de Physiology, Universidade Federal de São Paulo, São Paulo, Sao Paulo, Brazil
| | - Laís Gabrielle Vieira
- Department of de Physiology, Universidade Federal de São Paulo, São Paulo, Sao Paulo, Brazil
| | - Daniela Macedo Moraes
- Department of de Physiology, Universidade Federal de São Paulo, São Paulo, Sao Paulo, Brazil
| | - Beatriz O Amorim
- Department of de Physiology, Universidade Federal de São Paulo, São Paulo, Sao Paulo, Brazil
| | | | - Clement Hamani
- Behavioural Neurobiology Laboratory, Centre for Addiction and Mental Health, Toronto, Canada.,Division of Neurosurgery, Toronto Western Hospital, University of Toronto, Toronto, Canada
| | - Luciene Covolan
- Department of de Physiology, Universidade Federal de São Paulo, São Paulo, Sao Paulo, Brazil
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18
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Neuroimaging in animal models of epilepsy. Neuroscience 2017; 358:277-299. [DOI: 10.1016/j.neuroscience.2017.06.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/27/2017] [Accepted: 06/28/2017] [Indexed: 02/06/2023]
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19
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Abstract
Development of spontaneous seizures is the hallmark of human epilepsy. There is a critical need for new epilepsy models in order to elucidate mechanisms responsible for leading to the development of spontaneous seizures and for testing new anti-epileptic compounds. Moreover, rodent models of epilepsy have clearly demonstrated that there are two independent seizure systems in the brain: 1) the forebrain seizure network required for the expression of clonic seizures mediated by forebrain neurocircuitry, and 2) the brainstem seizure network necessary for the expression of brainstem or tonic seizures mediated by brainstem neurocircuitry. In seizure naïve animals, these two systems are separate, but developing models that can explore the intersection of the forebrain and brainstem seizure systems or for elucidating mechanisms responsible for bringing these two seizure systems together may aid in our understanding of: 1) how seizures can become more complex overtime, and 2) sudden unexpected death in epilepsy (SUDEP) since propagation of seizure discharge from the forebrain seizure system to the brainstem seizure system may have an important role in SUDEP because many cardiorespiratory systems are localized in the brainstem. The repeated flurothyl seizure model of epileptogenesis, as described here, may aid in providing insight into these important epilepsy issues in addition to understanding how spontaneous seizures develop.
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Affiliation(s)
- Russell J Ferland
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY 12208, USA.,Department of Neurology, Albany Medical College, Albany, NY 12208, USA
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20
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Metabotropic glutamate receptor 2/3 density and its relation to the hippocampal neuropathology in a model of temporal lobe epilepsy in rats. Epilepsy Res 2016; 127:55-59. [DOI: 10.1016/j.eplepsyres.2016.08.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 08/01/2016] [Accepted: 08/12/2016] [Indexed: 11/23/2022]
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21
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Claßen AC, Kneissl S, Lang J, Tichy A, Pakozdy A. Magnetic resonance features of the feline hippocampus in epileptic and non-epileptic cats: a blinded, retrospective, multi-observer study. BMC Vet Res 2016; 12:165. [PMID: 27515840 PMCID: PMC4982318 DOI: 10.1186/s12917-016-0788-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Accepted: 08/03/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Hippocampal necrosis in cats has been reported to be associated with epileptic seizures. Magnetic resonance imaging (MRI) features of temporal lobe (TL) abnormalities in epileptic cats have been described but MR images from epileptic and non-epileptic individuals have not yet been systematically compared. TL abnormalities are highly variable in shape, size and signal, and therefore may lead to varying evaluations by different specialists. The aim of this study was to investigate whether there were differences in the appearance of the TL between epileptic and non-epileptic cats, and whether there were any relationships between TL abnormalities and seizure semiologies or other clinical findings. We also investigated interobserver agreement among three specialists. METHODS The MR images of 46 cats were reviewed independently by three observers, who were blinded to patient data, examination findings and the review of the other observers. Images were evaluated using a multiparametric scoring system developed for this study. Mann-Whitney U-tests and chi-square were used to analyse the differences between observers' evaluations. The kappa coefficient (k) and Fleiss' kappa coefficient were used to quantify interobserver agreement. RESULTS The overall interobserver agreement was moderate to good (k =0.405 to 0.615). The MR scores between epileptic and non-epileptic cats did not differ significantly. However, there was a significant difference between the MR scores of epileptic cats with and without orofacial involvement according to all three observers. Likewise, MR scores of cats with cluster seizures were higher than those of cats without clusters. CONCLUSION Cats presenting with recurrent epileptic seizures with orofacial involvement are more likely to have hippocampal pathologies, which suggests that TL abnormalities are not merely unspecific epileptic findings, but are associated with a certain type of epilepsy. TL signal alterations are more likely to be detected on FLAIR sequences. In contrast to severe changes in the TL which were described similarly among specialists, mild TL abnormalities may be difficult to interpret, thus leading to different assessments among observers.
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Affiliation(s)
| | - Sibylle Kneissl
- Clinical Unit of Diagnostic Imaging, University of Veterinary Medicine, A 1210, Vienna, Austria
| | - Johann Lang
- Division of Clinical Radiology, Vetsuisse Faculty, University of Bern, CH 3012, Bern, Switzerland
| | - Alexander Tichy
- Department of Biomedical Sciences, University of Veterinary Medicine, A 1210, Vienna, Austria
| | - Akos Pakozdy
- Clinic for Internal Medicine, University of Veterinary Medicine, A 1210, Vienna, Austria
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22
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Effects of A1 receptor agonist/antagonist on spontaneous seizures in pilocarpine-induced epileptic rats. Epilepsy Behav 2016; 61:168-173. [PMID: 27371881 DOI: 10.1016/j.yebeh.2016.05.036] [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: 04/04/2016] [Revised: 05/27/2016] [Accepted: 05/28/2016] [Indexed: 12/20/2022]
Abstract
Adenosine is an endogenous anticonvulsant that activates pre- and postsynaptic adenosine A1 receptors. A1 receptor agonists increase the latency for the development of seizures and status epilepticus following pilocarpine administration. Although hippocampal adenosine is increased in the chronic phase of the pilocarpine model, it is not known whether the modulation of A1 receptors may influence the frequency of spontaneous recurrent seizures (SRS). Here, we tested the hypothesis that the A1 receptor agonist RPia ([R]-N-phenylisopropyladenosine) and the A1 antagonist DPCPX (8-Cyclopentyl-1,3-dipropylxanthine) administered to chronic pilocarpine epileptic rats would respectively decrease and increase the frequency of SRS and hippocampal excitability. Four months after Pilo-induced SE, chronic epileptic rats were video-monitored for the recording of SRS before (basal) and after a 2-week treatment with RPia (25μg/kg) or DPCPX (50μg/kg). Following sacrifice, brain slices were studied with electrophysiology. We found that rats given RPia had a 93% nonsignificant reduction in the frequency of seizures compared with their own pretreatment baseline. In contrast, the administration of DPCPX resulted in an 87% significant increase in seizure rate. Nontreated epileptic rats had a similar frequency of seizures along the study. Corroborating our behavioral data, in vitro recordings showed that slices from animals previously given DPCPX had a shorter latency to develop epileptiform activity, longer and higher DC shifts, and higher spike amplitude compared with slices from nontreated Pilo controls. In contrast, smaller spike amplitude was recorded in slices from animals given RPia. In summary, the administration of A1 agonists reduced hippocampal excitability but not the frequency of spontaneous recurrent seizures in chronic epileptic rats, whereas A1 receptor antagonists increased both.
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23
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Serotonin receptor antagonists increase fast ripple activity in rats treated with kainic acid. Brain Res Bull 2016; 121:59-67. [DOI: 10.1016/j.brainresbull.2016.01.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/30/2015] [Accepted: 01/04/2016] [Indexed: 11/22/2022]
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24
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Umpierre AD, Bennett IV, Nebeker LD, Newell TG, Tian BB, Thomson KE, White HS, White JA, Wilcox KS. Repeated low-dose kainate administration in C57BL/6J mice produces temporal lobe epilepsy pathology but infrequent spontaneous seizures. Exp Neurol 2016; 279:116-126. [PMID: 26896834 DOI: 10.1016/j.expneurol.2016.02.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Revised: 01/29/2016] [Accepted: 02/15/2016] [Indexed: 12/31/2022]
Abstract
More efficient or translationally relevant approaches are needed to model acquired temporal lobe epilepsy (TLE) in genetically tractable mice. The high costs associated with breeding and maintaining transgenic, knock-in, or knock-out lines place a high value on the efficiency of induction and animal survivability. Herein, we describe our approaches to model acquired epilepsy in C57BL/6J mice using repeated, low-dose kainate (KA) administration paradigms. Four paradigms (i.p.) were tested for their ability to induce status epilepticus (SE), temporal lobe pathology, and the development of epilepsy. All four paradigms reliably induce behavioral and/or electrographic SE without mortality over a 7d period. Two of the four paradigms investigated produce features indicative of TLE pathology, including hippocampal cell death, widespread astrogliosis, and astrocyte expression of mGluR5, a feature commonly reported in TLE models. Three of the investigated paradigms were able to produce aberrant electrographic features, such as interictal spiking in cortex. However, only one paradigm, previously published by others, produces spontaneous recurrent seizures over an eight week period. Presentation of spontaneous seizures is rare (N=2/14), with epilepsy preferentially developing in animals having a high number of seizures during SE. Overall, repeated, low-dose KA administration improves the efficiency and pathological relevance of a systemic KA insult, but does not produce a robust epilepsy phenotype under the experimental paradigms described herein.
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Affiliation(s)
- Anthony D Umpierre
- Interdepartmental Program in Neuroscience, University of Utah, 401 MREB, 20N. 1900E, Salt Lake City, UT 84132, United States.
| | - Isaiah V Bennett
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States.
| | - Lismore D Nebeker
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States.
| | - Thomas G Newell
- Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States; Dept. of Bioengineering, University of Utah, 36S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, United States.
| | - Bruce B Tian
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States.
| | - Kyle E Thomson
- Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States; Dept. of Bioengineering, University of Utah, 36S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, United States.
| | - H Steve White
- Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States; Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States; Department of Pharmacy, University of Washington, Box 357630, H375 Health Science Building, Seattle, WA 98195, United States.
| | - John A White
- Dept. of Biomedical Engineering, Boston University, 44 Cummington Mall, Rm. 403, Boston, MA 02215, United States.
| | - Karen S Wilcox
- Interdepartmental Program in Neuroscience, University of Utah, 401 MREB, 20N. 1900E, Salt Lake City, UT 84132, United States; Dept. of Pharmacology & Toxicology, University of Utah, College of Pharmacy, 30N. 1900E, Salt Lake City, UT 84112, United States; Anticonvulsant Drug Development Program, University of Utah, 417 Wakara Way, Suite 3211, Salt Lake City, UT 84108, United States.
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25
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Relationship between seizure frequency and number of neuronal and non-neuronal cells in the hippocampus throughout the life of rats with epilepsy. Brain Res 2016; 1634:179-186. [PMID: 26764534 DOI: 10.1016/j.brainres.2015.12.055] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 12/11/2015] [Accepted: 12/26/2015] [Indexed: 11/22/2022]
Abstract
The relationship between seizure frequency and cell death has been a subject of controversy. To tackle this issue, we determined the frequency of seizures and the total number of hippocampal cells throughout the life of rats with epilepsy using the pilocarpine model. Seizure frequency varied in animals with epilepsy according to which period of life they were in, with a progressive increase in the number of seizures until 180 days (sixth months) of epileptic life followed by a decrease (330 days-eleventh month) and subsequently stabilization of seizures. Cell counts by means of isotropic fractionation showed a reduction in the number of hippocampal neuronal cells following 30, 90, 180 and 360 days of spontaneous recurrent seizures (SRS) in rats compared to their controls (about 25%-30% of neuronal cell reduction). In addition, animals with 360 days of SRS showed a reduction in the number of neuronal cells when compared with animals with 90 and 180 days of seizures. The total number of hippocampal non-neuronal cells was reduced in rats with epilepsy after 30 days of SRS, but no significant alteration was observed on the 90th, 180th and 360th days. The total number of neuronal cells was negatively correlated with seizure frequency, indicating an association between occurrence of epileptic seizures throughout life and neuronal loss. In sum, our results add novel data to the literature concerning the time-course of SRS and hippocampal cell number throughout epileptic life.
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Behr C, Lévesque M, Ragsdale D, Avoli M. Lacosamide modulates interictal spiking and high-frequency oscillations in a model of mesial temporal lobe epilepsy. Epilepsy Res 2015; 115:8-16. [PMID: 26220372 PMCID: PMC4878889 DOI: 10.1016/j.eplepsyres.2015.05.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 04/28/2015] [Accepted: 05/12/2015] [Indexed: 01/19/2023]
Abstract
OBJECTIVE Nearly one third of patients presenting with mesial temporal lobe epilepsy (MTLE), the most prevalent lesion-related epileptic disorder in adulthood, do not respond to currently available antiepileptic medications. Thus, there is a need to identify and characterize new antiepileptic drugs. In this study, we used the pilocarpine model of MTLE to establish the effects of a third generation drug, lacosamide (LCM), on seizures, interictal spikes and high-frequency oscillations (HFOs, ripples: 80-200 Hz, fast ripples: 250-500 Hz). METHODS Sprague-Dawley rats (250-300 g) were injected with pilocarpine to induce a status epilepticus (SE) that was pharmacologically terminated after 1h. Eight pilocarpine-treated rats were then injected with LCM (30 mg/kg, i.p.) 4h after SE and daily for 14 days. Eight pilocarpine-treated rats were used as controls and treated with saline. Three days after SE, all rats were implanted with bipolar electrodes in the hippocampal CA3 region, entorhinal cortex (EC), dentate gyrus (DG) and subiculum and EEG-video monitored from day 4 to day 14 after SE. RESULTS LCM-treated animals showed lower rates of seizures (0.21 (± 0.11) seizures/day) than controls (2.6 (±0.57), p<0.05), and a longer latent period (LCM: 11 (± 1) days, controls: 6.25 (± 1), p<0.05). Rates of interictal spikes in LCM-treated rats were significantly lower than in controls in CA3 and subiculum (p<0.05). Rates of ripples and fast ripples associated with interictal spikes in CA3 and subiculum as well as rates of fast ripples occurring outside of interictal spikes in CA3 were also significantly lower in LCM-treated animals. In controls, interictal spikes and associated HFOs correlated to seizure clustering, while this was not the case for isolated HFOs. SIGNIFICANCE Our findings show that early treatment with LCM has powerful anti-ictogenic properties in the pilocarpine model of MTLE. These effects are accompanied by decreased rates of interictal spikes and associated HFOs. Isolated HFOs were also modulated by LCM, in a manner that appeared to be unrelated to its antiictogenic effects. These results thus suggest that distinct mechanisms may underlie interictal-associated and isolated HFOs in the pilocarpine model of MTLE.
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Affiliation(s)
- Charles Behr
- Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, QC, Canada H3A 2B4
| | - Maxime Lévesque
- Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, QC, Canada H3A 2B4
| | - David Ragsdale
- Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, QC, Canada H3A 2B4
| | - Massimo Avoli
- Montreal Neurological Institute and Department of Neurology & Neurosurgery, McGill University, 3801 University Street, Montréal, QC, Canada H3A 2B4.
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Malheiros JM, Paiva FF, Longo BM, Hamani C, Covolan L. Manganese-Enhanced MRI: Biological Applications in Neuroscience. Front Neurol 2015. [PMID: 26217304 PMCID: PMC4498388 DOI: 10.3389/fneur.2015.00161] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Magnetic resonance imaging (MRI) is an excellent non-invasive tool to investigate biological systems. The administration of the paramagnetic divalent ion manganese (Mn2+) enhances MRI contrast in vivo. Due to similarities between Mn2+ and calcium (Ca2+), the premise of manganese-enhanced MRI (MEMRI) is that the former may enter neurons and other excitable cells through voltage-gated Ca2+ channels. As such, MEMRI has been used to trace neuronal pathways, define morphological boundaries, and study connectivity in morphological and functional imaging studies. In this article, we provide a brief overview of MEMRI and discuss recently published data to illustrate the usefulness of this method, particularly in animal models.
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Affiliation(s)
- Jackeline Moraes Malheiros
- Department of Physiology, Universidade Federal de São Paulo - UNIFESP , São Paulo , Brazil ; Centro de Imagens e Espectroscopia In vivo por Ressonância Magnética, Institute of Physics of São Carlos, Universidade de São Paulo , São Carlos , Brazil
| | - Fernando Fernandes Paiva
- Centro de Imagens e Espectroscopia In vivo por Ressonância Magnética, Institute of Physics of São Carlos, Universidade de São Paulo , São Carlos , Brazil
| | - Beatriz Monteiro Longo
- Department of Physiology, Universidade Federal de São Paulo - UNIFESP , São Paulo , Brazil
| | - Clement Hamani
- Department of Physiology, Universidade Federal de São Paulo - UNIFESP , São Paulo , Brazil ; Research Imaging Centre, Centre for Addiction and Mental Health , Toronto, ON , Canada ; Centre for Addiction and Mental Health, Campbell Family Mental Health Research Institute , Toronto, ON , Canada
| | - Luciene Covolan
- Department of Physiology, Universidade Federal de São Paulo - UNIFESP , São Paulo , Brazil
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Kuperman RA, Martin KW. Pharmacoresistent Partial Epilepsy Secondary to Progressive Inflammatory Poliodystrophy. Pediatr Neurol 2015; 53:83-7. [PMID: 25937386 DOI: 10.1016/j.pediatrneurol.2015.02.009] [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: 02/07/2015] [Accepted: 02/12/2015] [Indexed: 11/15/2022]
Abstract
BACKGROUND Epilepsy with progressive cortical volume loss is described secondary to energy failure such as mitochondrial disorders, infectious, or inflammatory etiologies and associated with temporal lobe epilepsy. Postmortem studies do not support that spontaneous seizures even if present for prolonged periods universally result in cortical volume loss. MAIN FINDINGS We describe two children with extratemporal pharmacoresistent epilepsy, slowly progressive gray matter volume loss over several years, and evidence of central nervous system inflammation. Brain magnetic resonance imaging changes and antibody profiles were not typical of a well-defined, antibody-mediated central nervous system syndrome such as N-methyl-D-aspartate receptor encephalitis. CONCLUSIONS These patients illustrate a novel presentation of a subacute inflammatory central nervous system process with epilepsy and progressive cortical volume loss, supporting the role of sequential brain imaging in children with epilepsy.
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Affiliation(s)
- Rachel A Kuperman
- Pediatric Neurology, Children's Hospital and Research Center, Oakland, California.
| | - Kenneth W Martin
- Pediatric Radiology, Children's Hospital and Research Center, Oakland, California
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Naringin Attenuates Autophagic Stress and Neuroinflammation in Kainic Acid-Treated Hippocampus In Vivo. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2015; 2015:354326. [PMID: 26124853 PMCID: PMC4466392 DOI: 10.1155/2015/354326] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/27/2015] [Indexed: 01/21/2023]
Abstract
Kainic acid (KA) is well known as a chemical compound to study epileptic seizures and neuronal excitotoxicity. KA-induced excitotoxicity causes neuronal death by induction of autophagic stress and microglia-derived neuroinflammation, suggesting that the control of KA-induced effects may be important to inhibit epileptic seizures with neuroprotection. Naringin, a flavonoid in grapefruit and citrus fruits, has anti-inflammatory and antioxidative activities, resulting in neuroprotection in animal models from neurodegenerative diseases such as Parkinson's disease and Alzheimer's disease. In the present study, we examined its beneficial effects involved in antiautophagic stress and antineuroinflammation in the KA-treated hippocampus. Our results showed that naringin treatment delayed the onset of KA-induced seizures and decreased the occurrence of chronic spontaneous recurrent seizures (SRS) in KA-treated mice. Moreover, naringin treatment protected hippocampal CA1 neurons in the KA-treated hippocampus, ameliorated KA-induced autophagic stress, confirmed by the expression of microtubule-associated protein light chain 3 (LC3), and attenuated an increase in tumor necrosis factor-α (TNFα) in activated microglia. These results suggest that naringin may have beneficial effects of preventing epileptic events and neuronal death through antiautophagic stress and antineuroinflammation in the hippocampus in vivo.
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Gorter JA, van Vliet EA, Lopes da Silva FH. Which insights have we gained from the kindling and post-status epilepticus models? J Neurosci Methods 2015; 260:96-108. [PMID: 25842270 DOI: 10.1016/j.jneumeth.2015.03.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 03/23/2015] [Accepted: 03/24/2015] [Indexed: 11/24/2022]
Abstract
Experimental animal epilepsy research got a big boost since the discovery that daily mild and short (seconds) tetanic stimulations in selected brain regions led to seizures with increasing duration and severity. This model that was developed by Goddard (1967) became known as the kindling model for epileptogenesis and has become a widely used model for temporal lobe epilepsy with complex partial seizures. During the late ninety-eighties the number of publications related to electrical kindling reached its maximum. However, since the kindling procedure is rather labor intensive and animals only develop spontaneous seizures (epilepsy) after hundreds of stimulations, research has shifted toward models in which the animals exhibit spontaneous seizures after a relatively short latent period. This led to post-status epilepticus (SE) models in which animals experience SE after injection of pharmacological compounds (e.g. kainate or pilocarpine) or via electrical stimulation of (limbic) brain regions. These post-SE models are the most widely used models in epilepsy research today. However, not all aspects of mesial temporal lobe epilepsy (MTLE) are reproduced and the widespread brain damage is often a caricature of the situation in the patient. Therefore, there is a need for models that can better replicate the disease. Kindling, although already a classic model, can still offer valid clues in this context. In this paper, we review different aspects of the kindling model with emphasis on experiments in the rat. Next, we review characteristic properties of the post-SE models and compare the neuropathological, electrophysiological and molecular differences between kindling and post-SE epilepsy models. Finally, we shortly discuss the advantages and disadvantages of these models.
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Affiliation(s)
- Jan A Gorter
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands.
| | - Erwin A van Vliet
- Department of (Neuro)Pathology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Fernando H Lopes da Silva
- Center for Neuroscience, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands; Instituto Superior Técnico, University of Lisbon, 1049-001 Lisbon, Portugal
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Animal models of temporal lobe epilepsy following systemic chemoconvulsant administration. J Neurosci Methods 2015; 260:45-52. [PMID: 25769270 DOI: 10.1016/j.jneumeth.2015.03.009] [Citation(s) in RCA: 150] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Revised: 03/03/2015] [Accepted: 03/04/2015] [Indexed: 01/23/2023]
Abstract
In order to understand the pathophysiology of temporal lobe epilepsy (TLE), and thus to develop new pharmacological treatments, in vivo animal models that present features similar to those seen in TLE patients have been developed during the last four decades. Some of these models are based on the systemic administration of chemoconvulsants to induce an initial precipitating injury (status epilepticus) that is followed by the appearance of recurrent seizures originating from limbic structures. In this paper we will review two chemically-induced TLE models, namely the kainic acid and pilocarpine models, which have been widely employed in basic epilepsy research. Specifically, we will take into consideration their behavioral, electroencephalographic and neuropathologic features. We will also evaluate the response of these models to anti-epileptic drugs and the impact they might have in developing new treatments for TLE.
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Szilágyi T, Száva I, Metz EJ, Mihály I, Orbán-Kis K. Untangling the pathomechanisms of temporal lobe epilepsy—The promise of epileptic biomarkers and novel therapeutic approaches. Brain Res Bull 2014; 109:1-12. [DOI: 10.1016/j.brainresbull.2014.08.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 08/11/2014] [Accepted: 08/14/2014] [Indexed: 12/30/2022]
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