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Tripathi S, Nathan CL, Tate MC, Horbinski CM, Templer JW, Rosenow JM, Sita TL, James CD, Deneen B, Miller SD, Heimberger AB. The immune system and metabolic products in epilepsy and glioma-associated epilepsy: emerging therapeutic directions. JCI Insight 2024; 9:e174753. [PMID: 38193532 PMCID: PMC10906461 DOI: 10.1172/jci.insight.174753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024] Open
Abstract
Epilepsy has a profound impact on quality of life. Despite the development of new antiseizure medications (ASMs), approximately one-third of affected patients have drug-refractory epilepsy and are nonresponsive to medical treatment. Nearly all currently approved ASMs target neuronal activity through ion channel modulation. Recent human and animal model studies have implicated new immunotherapeutic and metabolomic approaches that may benefit patients with epilepsy. In this Review, we detail the proinflammatory immune landscape of epilepsy and contrast this with the immunosuppressive microenvironment in patients with glioma-related epilepsy. In the tumor setting, excessive neuronal activity facilitates immunosuppression, thereby contributing to subsequent glioma progression. Metabolic modulation of the IDH1-mutant pathway provides a dual pathway for reversing immune suppression and dampening seizure activity. Elucidating the relationship between neurons and immunoreactivity is an area for the prioritization and development of the next era of ASMs.
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Affiliation(s)
- Shashwat Tripathi
- Department of Neurological Surgery
- Malnati Brain Tumor Institute of the Robert H. Lurie Comprehensive Cancer Center
| | | | | | - Craig M. Horbinski
- Malnati Brain Tumor Institute of the Robert H. Lurie Comprehensive Cancer Center
- Department of Pathology, and
| | | | | | - Timothy L. Sita
- Department of Neurological Surgery
- Department of Radiation Oncology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Charles D. James
- Department of Neurological Surgery
- Malnati Brain Tumor Institute of the Robert H. Lurie Comprehensive Cancer Center
| | - Benjamin Deneen
- Department of Neurosurgery, Baylor College of Medicine, Houston, Texas, USA
| | - Stephen D. Miller
- Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
| | - Amy B. Heimberger
- Department of Neurological Surgery
- Malnati Brain Tumor Institute of the Robert H. Lurie Comprehensive Cancer Center
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Sri Hari A, Banerji R, Liang LP, Fulton RE, Huynh CQ, Fabisiak T, McElroy PB, Roede JR, Patel M. Increasing glutathione levels by a novel posttranslational mechanism inhibits neuronal hyperexcitability. Redox Biol 2023; 67:102895. [PMID: 37769522 PMCID: PMC10539966 DOI: 10.1016/j.redox.2023.102895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/14/2023] [Accepted: 09/18/2023] [Indexed: 10/02/2023] Open
Abstract
Glutathione (GSH) depletion, and impaired redox homeostasis have been observed in experimental animal models and patients with epilepsy. Pleiotropic strategies that elevate GSH levels via transcriptional regulation have been shown to significantly decrease oxidative stress and seizure frequency, increase seizure threshold, and rescue certain cognitive deficits. Whether elevation of GSH per se alters neuronal hyperexcitability remains unanswered. We previously showed that thiols such as dimercaprol (DMP) elevate GSH via post-translational activation of glutamate cysteine ligase (GCL), the rate limiting GSH biosynthetic enzyme. Here, we asked if elevation of cellular GSH by DMP altered neuronal hyperexcitability in-vitro and in-vivo. Treatment of primary neuronal-glial cerebrocortical cultures with DMP elevated GSH and inhibited a voltage-gated potassium channel blocker (4-aminopyridine, 4AP) induced neuronal hyperexcitability. DMP increased GSH in wildtype (WT) zebrafish larvae and significantly attenuated convulsant pentylenetetrazol (PTZ)-induced acute 'seizure-like' swim behavior. DMP treatment increased GSH and inhibited convulsive, spontaneous 'seizure-like' swim behavior in the Dravet Syndrome (DS) zebrafish larvae (scn1Lab). Furthermore, DMP treatment significantly decreased spontaneous electrographic seizures and associated seizure parameters in scn1Lab zebrafish larvae. We investigated the role of the redox-sensitive mammalian target of rapamycin (mTOR) pathway due to the presence of several cysteine-rich proteins and their involvement in regulating neuronal excitability. Treatment of primary neuronal-glial cerebrocortical cultures with 4AP or l-buthionine-(S,R)-sulfoximine (BSO), an irreversible inhibitor of GSH biosynthesis, significantly increased mTOR complex I (mTORC1) activity which was rescued by pre-treatment with DMP. Furthermore, BSO-mediated GSH depletion oxidatively modified the tuberous sclerosis protein complex (TSC) consisting of hamartin (TSC1), tuberin (TSC2), and TBC1 domain family member 7 (TBC1D7) which are critical negative regulators of mTORC1. In summary, our results suggest that DMP-mediated GSH elevation by a novel post-translational mechanism can inhibit neuronal hyperexcitability both in-vitro and in-vivo and a plausible link is the redox sensitive mTORC1 pathway.
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Affiliation(s)
- Ashwini Sri Hari
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Rajeswari Banerji
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Li-Ping Liang
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Ruth E Fulton
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Christopher Quoc Huynh
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Timothy Fabisiak
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Pallavi Bhuyan McElroy
- The Janssen Pharmaceutical Companies of Johnson & Johnson, Greater Philadelphia Area, Horsham, PA, 19044, USA
| | - James R Roede
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA
| | - Manisha Patel
- Department of Pharmaceutical Sciences, University of Colorado, Anschutz Medical Campus, Aurora, CO, 80045, USA.
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Almeida C, Pongilio RP, Móvio MI, Higa GSV, Resende RR, Jiang J, Kinjo ER, Kihara AH. Distinct Cell-specific Roles of NOX2 and MyD88 in Epileptogenesis. Front Cell Dev Biol 2022; 10:926776. [PMID: 35859905 PMCID: PMC9289522 DOI: 10.3389/fcell.2022.926776] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 06/15/2022] [Indexed: 02/05/2023] Open
Abstract
It is well established that temporal lobe epilepsy (TLE) is often related to oxidative stress and neuroinflammation. Both processes subserve alterations observed in epileptogenesis and ultimately involve distinct classes of cells, including astrocytes, microglia, and specific neural subtypes. For this reason, molecules associated with oxidative stress response and neuroinflammation have been proposed as potential targets for therapeutic strategies. However, these molecules can participate in distinct intracellular pathways depending on the cell type. To illustrate this, we reviewed the potential role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and myeloid differentiation primary response 88 (MyD88) in astrocytes, microglia, and neurons in epileptogenesis. Furthermore, we presented approaches to study genes in different cells, employing single-cell RNA-sequencing (scRNAseq) transcriptomic analyses, transgenic technologies and viral serotypes carrying vectors with specific promoters. We discussed the importance of identifying particular roles of molecules depending on the cell type, endowing more effective therapeutic strategies to treat TLE.
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Affiliation(s)
- Cayo Almeida
- Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo, Brazil
| | | | - Marília Inês Móvio
- Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo, Brazil
| | | | - Rodrigo Ribeiro Resende
- Laboratório de Sinalização Celular e Nanobiotecnologia, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
| | - Jianxiong Jiang
- Department of Pharmaceutical Sciences, College of Pharmacy, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Erika Reime Kinjo
- Laboratório de Neurogenética, Universidade Federal do ABC, São Bernardo do Campo, Brazil
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The Antioxidant Effect of Medicago sativa L. (Alfalfa) Ethanolic Extract against Mercury Chloride (HgCl 2) Toxicity in Rat Liver and Kidney: An In Vitro and In Vivo Study. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2021; 2021:8388002. [PMID: 34484406 PMCID: PMC8413032 DOI: 10.1155/2021/8388002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 08/04/2021] [Accepted: 08/14/2021] [Indexed: 11/17/2022]
Abstract
Heavy metals such as mercury are some of the environmental pollutants and can induce toxicity by bioaccumulation and oxidative damage. This study aimed to investigate the effect of ethanolic extract of Medicago sativa L. (Alfalfa) on mercury damage in the kidney and liver of rats. Thirty Wistar rats were randomly divided into five groups, the control group, S group (2 mg/kg mercury chloride), and T1, T2, and T3 groups that, in addition to mercury, received doses of 250, 500, and 750 mg/kg of the alfalfa extract. On the last day, blood samples were taken, and the serum was separated to measure biochemical and oxidative stress parameters in the kidney and liver. A part of the kidney and liver was also used for histopathological evaluation. Total phenols and flavonoids were 40.45 ± 2.12 and 14.36 ± 0.45 mg/g, respectively, whereas IC50 was 245.18 ± 19.76 μg/ml. The body weight significantly decreased in the S group compared to other groups, while treatment with different doses of alfalfa extract increased the body weight. Mercury concentration in the kidney was higher than that in the liver. The serum levels of urea, creatinine, alanine aminotransferase (ALT), and alkaline phosphatase (ALP) significantly increased in the S group compared to the control group, while treatment with different doses of alfalfa extract increased their levels. Moreover, an increase in malondialdehyde (MDA) and a decrease in glutathione peroxidase (GPx), catalase (CAT), total antioxidant capacity (TAC), and superoxide dismutase (SOD) activity were observed in the S group. The level of these parameters significantly improved in the groups receiving the extract compared to the S group. Furthermore, the histopathological evaluation showed glomerular and tubular damage and hepatic necrosis in the S group and that these conditions improved in the T3 group. The findings of this study showed that the ethanolic extract of alfalfa in a dose-dependent manner has potentially unique protective effects against mercury poisoning in the kidney and liver.
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McDonald T, Puchowicz M, Borges K. Impairments in Oxidative Glucose Metabolism in Epilepsy and Metabolic Treatments Thereof. Front Cell Neurosci 2018; 12:274. [PMID: 30233320 PMCID: PMC6127311 DOI: 10.3389/fncel.2018.00274] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Accepted: 08/06/2018] [Indexed: 12/19/2022] Open
Abstract
There is mounting evidence that oxidative glucose metabolism is impaired in epilepsy and recent work has further characterized the metabolic mechanisms involved. In healthy people eating a traditional diet, including carbohydrates, fats and protein, the major energy substrate in brain is glucose. Cytosolic glucose metabolism generates small amounts of energy, but oxidative glucose metabolism in the mitochondria generates most ATP, in addition to biosynthetic precursors in cells. Energy is crucial for the brain to signal "normally," while loss of energy can contribute to seizure generation by destabilizing membrane potentials and signaling in the chronic epileptic brain. Here we summarize the known biochemical mechanisms that contribute to the disturbance in oxidative glucose metabolism in epilepsy, including decreases in glucose transport, reduced activity of particular steps in the oxidative metabolism of glucose such as pyruvate dehydrogenase activity, and increased anaplerotic need. This knowledge justifies the use of alternative brain fuels as sources of energy, such as ketones, TCA cycle intermediates and precursors as well as even medium chain fatty acids and triheptanoin.
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Affiliation(s)
- Tanya McDonald
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
| | - Michelle Puchowicz
- Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Karin Borges
- School of Biomedical Sciences, Faculty of Medicine, The University of Queensland, Brisbane, QLD, Australia
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Al-Attar AM, Elnaggar MH, Almalki EA. Protective effect of some plant oils on diazinon induced hepatorenal toxicity in male rats. Saudi J Biol Sci 2017; 24:1162-1171. [PMID: 28855808 PMCID: PMC5562457 DOI: 10.1016/j.sjbs.2016.10.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Revised: 10/07/2016] [Accepted: 10/09/2016] [Indexed: 12/16/2022] Open
Abstract
Environmental pollution and exposure to environmental pollutants are still some of the major global health issues. Pesticides have been linked to a wide range of health hazards. The toxicity of pesticides depends on several factors such as its chemical properties, doses, exposure period, exposure methods, gender, genetics, age, nutritional status and physiological case of exposed individuals. Medicinal plants, natural products and nutrition continue to play a central role in the healthcare system of large proportions of the world's population. Alternative medicine plays an important role in health services around the world. The aim of this study was to investigate the effect of olive, sesame and black seed oils on hepatorenal toxicity induced by diazinon (DZN) in male rats. The experimental animals were divided into nine groups. The first group served as control. The second group was exposed to DZN. The third group was treated with olive oil and DZN. Rats of the fourth group were subjected to sesame oil and DZN. Rats of the fifth group were exposed to black seed oil and DZN. The sixth, seventh and eighth groups were supplemented with olive, sesame and black seed oils respectively. Rats of the ninth group were treated with corn oil. Levels of serum alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, gamma glutamyl transferase, total bilirubin, creatinine, blood urea nitrogen and malondialdehyde were significantly increased in rats exposed to DZN. Moreover, levels of serum glutathione and superoxide dismutase were significantly decreased. Several histopathological changes were observed in the structures of liver and kidney due to DZN exposure. This study showed that these oils attenuated the physiological disturbances and histopathological alterations induced by DZN intoxication. Moreover, the antioxidant properties of these oils support the bioactive roles of its protective effects on DZN toxicity. This study therefore suggests that these oils could be used as preventive factors against the toxicity of DZN due to its antioxidant properties.
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Affiliation(s)
- Atef M. Al-Attar
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University, P.O. Box 139109, Jeddah 21323, Saudi Arabia
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7
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Sun J, Gao X, Meng D, Xu Y, Wang X, Gu X, Guo M, Shao X, Yan H, Jiang C, Zheng Y. Antagomirs Targeting MiroRNA-134 Attenuates Epilepsy in Rats through Regulation of Oxidative Stress, Mitochondrial Functions and Autophagy. Front Pharmacol 2017; 8:524. [PMID: 28848439 PMCID: PMC5550691 DOI: 10.3389/fphar.2017.00524] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 07/25/2017] [Indexed: 01/03/2023] Open
Abstract
The effects of the existing anti-epileptic drugs are unsatisfactory to almost one third of epileptic patients. MiR-134 antagomirs prevent pilocarpine-induced status epilepticus. In this study, a lithium chloride-pilocarpine-induced status epilepticus model was established and treated with intracerebroventricular injection of antagomirs targeting miR-134 (Ant-134). The Ant-134 treatment significantly improved the performance of rats in Morris water maze tests, inhibited mossy fiber sprouting in the dentate gyrus, and increased the survival neurons in the hippocampal CA1 region. Silencing of miR-134 remarkably decreased malonaldehyde and 4-hydroxynonenal levels and increased superoxide dismutase activity in the hippocampus. The Ant-134 treatment also significantly increased the production of ATP and the activities of mitochondrial respiratory enzyme complexes and significantly decreased the reactive oxygen species generation in the hippocampus compared with the status epilepticus rats. Finally, the Ant-134 treatment remarkably downregulated the hippocampal expressions of autophagy-associated proteins Atg5, beclin-1 and light chain 3B. In conclusion, Ant-134 attenuates epilepsy via inhibiting oxidative stress, improving mitochondrial functions and regulating autophagy in the hippocampus.
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Affiliation(s)
- Jiahang Sun
- Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical UniversityHarbin, China
| | - Xiaoying Gao
- Department of Anesthesiology, The Fourth Affiliated Hospital of Harbin Medical UniversityHarbin, China
| | - Dawei Meng
- Department of Neurosurgery, China Medical University Aviation General HospitalBeijing, China
| | - Yang Xu
- Department of Urology, Harbin Medical University Cancer HospitalHarbin, China
| | - Xichun Wang
- Department of Neurosurgery, Heilongjiang Provincial HospitalHarbin, China
| | - Xin Gu
- Department of Head and Neck Surgery, Harbin Medical University Cancer HospitalHarbin, China
| | - Mian Guo
- Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical UniversityHarbin, China
| | - Xiaodong Shao
- School of Basic Medical Sciences, Harbin Medical UniversityHarbin, China
| | - Hongwen Yan
- Department of Pediatric Hematology, Peking University International HospitalBeijing, China
| | - Chuanlu Jiang
- Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical UniversityHarbin, China
| | - Yongri Zheng
- Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical UniversityHarbin, China
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Venediktova NI, Gorbacheva OS, Belosludtseva NV, Fedotova IB, Surina NM, Poletaeva II, Kolomytkin OV, Mironova GD. Energetic, oxidative and ionic exchange in rat brain and liver mitochondria at experimental audiogenic epilepsy (Krushinsky-Molodkina model). J Bioenerg Biomembr 2017; 49:149-158. [PMID: 28070860 DOI: 10.1007/s10863-016-9693-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 12/30/2016] [Indexed: 01/02/2023]
Abstract
The role of brain and liver mitochondria at epileptic seizure was studied on Krushinsky-Molodkina (KM) rats which respond to sound with an intensive epileptic seizure (audiogenic epilepsy). We didn't find significant changes in respiration rats of brain and liver mitochondria of KM and control rats; however the efficiency of АТР synthesis in the KM rat mitochondria was 10% lower. In rats with audiogenic epilepsy the concentration of oxidative stress marker malondialdehyde in mitochondria of the brain (but not liver) was 2-fold higher than that in the control rats. The rate of H2O2 generation in brain mitochondria of КМ rats was twofold higher than in the control animals when using NAD-dependent substrates. This difference was less pronounced in liver mitochondria. In KM rats, the activity of mitochondrial ATP-dependent potassium channel was lower than in liver mitochondria of control rats. The comparative study of the mitochondria ability to retain calcium ions revealed that in the case of using the complex I and complex II substrates, permeability transition pore is easier to trigger in brain and liver mitochondria of KM and КМs rats than in the control ones. The role of the changes in the energetic, oxidative, and ionic exchange in the mechanism of audiogenic epilepsy generation in rats and the possible correction of the epilepsy seizures are discussed.
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Affiliation(s)
- Natalya I Venediktova
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, 142290, Russia.
| | - Olga S Gorbacheva
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, 142290, Russia
| | - Natalia V Belosludtseva
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, 142290, Russia
| | - Irina B Fedotova
- Biology Department, Laboratory for Physiology and Genetics of Behavior, Lomonosov Moscow State University, Leninskie Gory, 1, Build. 12, Moscow, 119992, Russia
| | - Natalia M Surina
- Biology Department, Laboratory for Physiology and Genetics of Behavior, Lomonosov Moscow State University, Leninskie Gory, 1, Build. 12, Moscow, 119992, Russia
| | - Inga I Poletaeva
- Biology Department, Laboratory for Physiology and Genetics of Behavior, Lomonosov Moscow State University, Leninskie Gory, 1, Build. 12, Moscow, 119992, Russia
| | - Oleg V Kolomytkin
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, 142290, Russia
| | - Galina D Mironova
- Institute of Theoretical and Experimental Biophysics RAS, Pushchino, Moscow Region, 142290, Russia
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Okamura AMNC, Gomes PXL, de Oliveira GV, de Araújo FYR, Tomaz VS, Chaves Filho AJM, de Sousa FCF, Vasconcelos SMM, de Lucena DF, Macêdo D. N-acetylcysteine attenuates nicotine-induced kindling in female periadolescent rats. Prog Neuropsychopharmacol Biol Psychiatry 2016; 67:58-65. [PMID: 26812248 DOI: 10.1016/j.pnpbp.2016.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 12/22/2015] [Accepted: 01/22/2016] [Indexed: 11/29/2022]
Abstract
Kindling is a form of behavioral sensitization that is related to the progression of several neuropsychiatric disorders such as bipolar disorder. We recently demonstrated that female periadolescent rats are more vulnerable to nicotine (NIC)-induced kindling than their male counterparts. Furthermore, we evidenced that decreases in brain antioxidative defenses may contribute to this gender difference. Here we aimed to determine the preventive effects of the antioxidant N-acetyl cysteine (NAC) against NIC-kindling in female periadolescent rats. To do this female Wistar rats at postnatal day 30 received repeated injections of NIC 2mg/kg, i.p. every weekday for up to 19 days. NAC90, 180 or 270 mg/kg, i.p. was administered 30 min before NIC. The levels of glutathione (GSH), superoxide dismutase (SOD) activity, lipid peroxidation (LP) and nitrite were determined in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST). The development of kindling occurred at a median time of 16.5 days with 87.5% of NIC animals presenting stage 5 seizures in the last day of drug administration. NAC270 prevented the occurrence of kindling. NIC-kindled animals presented decreased levels of GSH and increased LP in the PFC, HC and ST, while SOD activity was decreased in the ST. NAC180 or 270 prevented the alterations in GSH induced by NIC, but only NAC270 prevented the alterations in LP. Nitrite levels increased in the ST of NAC270 pretreated NIC-kindled animals. Taken together we demonstrated that NAC presents anti-kindling effects in female animals partially through the restoration of oxidative alterations.
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Affiliation(s)
- Adriana Mary Nunes Costa Okamura
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Patrícia Xavier L Gomes
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Gersilene V de Oliveira
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Fernanda Yvelize R de Araújo
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Viviane S Tomaz
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Adriano José Maia Chaves Filho
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Francisca Cléa F de Sousa
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Silvânia Maria Mendes Vasconcelos
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - David Freitas de Lucena
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil
| | - Danielle Macêdo
- Drug Research and Development Center, Department of Physiology and Pharmacology, Faculty of Medicine, Federal University of Ceará, Fortaleza, CE, Brazil.
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10
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Tambe R, Jain P, Patil S, Ghumatkar P, Sathaye S. Antiepileptogenic effects of borneol in pentylenetetrazole-induced kindling in mice. Naunyn Schmiedebergs Arch Pharmacol 2016; 389:467-75. [DOI: 10.1007/s00210-016-1220-z] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2015] [Accepted: 02/09/2016] [Indexed: 01/10/2023]
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11
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Rettenbeck ML, von Rüden EL, Bienas S, Carlson R, Stein VM, Tipold A, Potschka H. Microglial ROS production in an electrical rat post-status epilepticus model of epileptogenesis. Neurosci Lett 2015; 599:146-51. [PMID: 26007700 DOI: 10.1016/j.neulet.2015.05.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 04/30/2015] [Accepted: 05/20/2015] [Indexed: 11/26/2022]
Abstract
Reactive oxygen species and inflammatory signaling have been identified as pivotal pathophysiological factors contributing to epileptogenesis. Considering the development of combined anti-inflammatory and antioxidant treatment strategies with antiepileptogenic potential, a characterization of the time course of microglial reactive oxygen species generation during epileptogenesis is of major interest. Thus, we isolated microglia cells and analyzed the generation of reactive oxygen species by flow cytometric analysis in an electrical rat post-status epilepticus model. Two days post status epilepticus, a large-sized cell cluster exhibited a pronounced response with excessive production of reactive oxygen species upon stimulation with phorbol-myristate-acetate. Neither in the latency phase nor in the chronic phase with spontaneous seizures a comparable cell population with induction of reactive oxygen species was identified. We were able to demonstrate in the electrical rat post-status-epilepticus model, that microglial ROS generation reaches a peak after the initial insult, is only marginally increased in the latency phase, and returns to control levels during the chronic epileptic phase. The data suggest that a combination of anti-inflammatory and radical scavenging approaches might only be beneficial during a short time window after an epileptogenic brain insult.
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Affiliation(s)
- Maruja L Rettenbeck
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | - Eva-Lotta von Rüden
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany
| | - Silvia Bienas
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Regina Carlson
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Veronika M Stein
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Andrea Tipold
- Department of Small Animal Medicine and Surgery, University of Veterinary Medicine Hannover, Hannover, Germany
| | - Heidrun Potschka
- Institute of Pharmacology, Toxicology, and Pharmacy, Ludwig-Maximilians-University, Munich, Germany.
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12
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Folbergrová J. Oxidative stress in immature brain following experimentally-induced seizures. Physiol Res 2014; 62:S39-48. [PMID: 24329702 DOI: 10.33549/physiolres.932613] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The existing data indicate that status epilepticus (SE) induced in immature animals is associated with oxidative stress and mitochondrial dysfunction. This has been demonstrated using two models of SE, induced by substances with a different mechanism of action (DL-homocysteic acid and 4-aminopyridine) which suggests that the findings are not model-dependent but they reflect more general phenomenon. Oxidative stress occurring in immature brain during and following seizures is apparently due to both the increased free radicals production and the limited antioxidant defense. Pronounced inhibition of mitochondrial complex I in immature brain was demonstrated not only during the acute phase of SE, but it persisted during long periods of survival, corresponding to the development of spontaneous seizures (epileptogenesis). The findings suggest that oxidative modification is most likely responsible for the sustained deficiency of complex I activity. It can be assumed that the substances with antioxidant properties combined with conventional therapies might provide a beneficial effect in treatment of epilepsy.
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Affiliation(s)
- J Folbergrová
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
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Otáhal J, Folbergrová J, Kovacs R, Kunz WS, Maggio N. Epileptic focus and alteration of metabolism. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2014; 114:209-43. [PMID: 25078504 DOI: 10.1016/b978-0-12-418693-4.00009-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Epilepsy is one of the most common neurologic disorders affecting a substantial part of the population worldwide. Epileptic seizures represent the situation of increased neuronal activity associated with the enhanced demands for sufficient energy supply. For that purpose, very efficient regulatory mechanisms have to operate to ensure that cerebral blood flow, delivery of oxygen, and nutrients are continuously adapted to the local metabolic needs. The sophisticated regulation has to function in concert at several levels (systemic, tissue, cellular, and subcellular). Particularly, mitochondria play a key role not only in the energy production, but they are also central to many other processes including those leading to neuronal death. Impairment of any of the involved pathways can result in serious functional alterations, neurodegeneration, and potentially in epileptogenesis. The present review will address some of the important issues concerning vascular and metabolic changes in pathophysiology of epilepsy.
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Affiliation(s)
- Jakub Otáhal
- Institute of Physiology, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic.
| | - Jaroslava Folbergrová
- Institute of Physiology, v.v.i., Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - Richard Kovacs
- Institute for Neurophysiology, Charité-Medical University Berlin, Berlin, Germany
| | - Wolfram S Kunz
- Department of Epileptology, University of Bonn, Bonn, Germany
| | - Nicola Maggio
- Department of Neurology, The Joseph Sagol Neuroscience Center, The Chaim Sheba Medical Center, Tel HaShomer, Israel; Talpiot Medical Leadership Program, The Chaim Sheba Medical Center, Tel HaShomer, Israel
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Khurana DS, Valencia I, Goldenthal MJ, Legido A. Mitochondrial dysfunction in epilepsy. Semin Pediatr Neurol 2013; 20:176-87. [PMID: 24331359 DOI: 10.1016/j.spen.2013.10.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Epilepsy is the most common neurologic disorder worldwide and is characterized by recurrent unprovoked seizures. The mitochondrial (mt) respiratory chain is the final common pathway for cellular energy production through the process of oxidative phosphorylation. As neurons are terminally differentiated cells that lack significant regenerative capacity and have a high energy demand, they are more vulnerable to mt dysfunction. Therefore, epileptic seizures have been well described in several diseases such as mt encephalomyopathy, lactic acidosis, and stroke-like episodes and myoclonic epilepsy and ragged red fibers, which are caused by gene mutations in mtDNA, among others. Mutations in nuclear DNA regulating mt function are also being described (eg, POLG gene mutation). The role of mitochondria (mt) in acquired epilepsies, which account for about 60% of all epilepsies, is equally important but less well understood. Oxidative stress is one of the possible mechanisms in the pathogenesis of epilepsy resulting from mt dysfunction gradually disrupting the intracellular Ca(2+) homeostasis, which modulates neuronal excitability and synaptic transmission, making neurons more vulnerable to additional stress, and leading to energy failure and neuronal loss in epilepsy. Antiepileptic drugs (AEDs) also affect mt function in several ways. There must be caution when treating epilepsy in patients with known mt disorders as some AEDs are toxic to the mt. This review summarizes our current knowledge of the effect of mt disorders on epilepsy, of epileptic seizures on mt, and of AEDs on mt function and the implications of all these interactions for the management of epilepsy in patients with or without mt disease.
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Affiliation(s)
- Divya S Khurana
- Section of Neurology, Departments of Pediatrics and Neurology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA.
| | - Ignacio Valencia
- Section of Neurology, Departments of Pediatrics and Neurology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA
| | - Michael J Goldenthal
- Section of Neurology, Departments of Pediatrics and Neurology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA
| | - Agustín Legido
- Section of Neurology, Departments of Pediatrics and Neurology, St. Christopher's Hospital for Children, Drexel University College of Medicine, Philadelphia, PA
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Khadrawy YA, AboulEzz HS, Ahmed NA, Mohammed HS. The Anticonvulant Effect of Cooling in Comparison to α-Lipoic Acid: A Neurochemical Study. Neurochem Res 2013; 38:906-15. [DOI: 10.1007/s11064-013-0995-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 01/28/2013] [Accepted: 01/31/2013] [Indexed: 11/29/2022]
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16
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Gomes PXL, de Oliveira GV, de Araújo FYR, de Barros Viana GS, de Sousa FCF, Hyphantis TN, Grunberg NE, Carvalho AF, Macêdo DS. Differences in vulnerability to nicotine-induced kindling between female and male periadolescent rats. Psychopharmacology (Berl) 2013; 225:115-26. [PMID: 22782460 DOI: 10.1007/s00213-012-2799-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 06/28/2012] [Indexed: 11/08/2022]
Abstract
RATIONALE It has recently been reported that chronic nicotine administration at subconvulsive doses causes seizures, a phenomenon referred to as kindling. Evidence points to the involvement of oxidative stress in pharmacological and electrical kindling, sex is known to influence the brain's response to nicotine. OBJECTIVES This study investigated the sex differences in vulnerability to nicotine-induced kindling and the involvement of oxidative stress in this phenomenon. METHODS Male and female periadolescent Wistar rats received repeated injections of a subconvulsive dose of nicotine (hemisulfate salt; 2 mg/kg, i.p.) every weekday for up to 25 days. To better understand the influence of oxidative stress in nicotine kindling, the antioxidant vitamin E (200 and 400 mg/kg, p.o.) was administered prior to nicotine administration. The levels of gluthatione (GSH), superoxide dismutase (SOD) activity, and lipid peroxidation were determined in the hippocampus (HC), prefrontal cortex (PFC), and striatum. RESULTS Female animals developed kindling more rapidly than male rats. In female rats, kindling was associated with decreases in antioxidant defenses, including GSH levels in the HC and striatum and SOD activity in the PFC and striatum, and increased lipid peroxidation in all brain areas studied. By contrast, male kindled animals presented only with a decrease in the GSH in the HC. Vitamin E prevented the occurrence of kindled seizures by 80 % and 75 % in male and female rats, respectively. CONCLUSION These novel findings indicate that female periadolescent rats develop nicotine-kindled seizures earlier than their male counterparts. Differences in the oxidative balance may be involved in this mechanism.
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Affiliation(s)
- Patrícia Xavier L Gomes
- Department of Physiology and Pharmacology, Federal University of Ceará, Rua Cel. Nunes de Melo 1127, Fortaleza 60431-270, Ceará, Brazil
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Martinc B, Grabnar I, Vovk T. The role of reactive species in epileptogenesis and influence of antiepileptic drug therapy on oxidative stress. Curr Neuropharmacol 2012; 10:328-43. [PMID: 23730257 PMCID: PMC3520043 DOI: 10.2174/157015912804143504] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Revised: 07/23/2012] [Accepted: 09/03/2012] [Indexed: 01/09/2023] Open
Abstract
Epilepsy is considered one of the most common neurological disorders. The focus of this review is the acquired form of epilepsy, with the development process consisting of three major phases, the acute injury phase, the latency epileptogenesis phase, and the phase of spontaneous recurrent seizures. Nowadays, an increasing attention is paid to the possible interrelationship between oxidative stress resulting in disturbance of physiological signalling roles of calcium and free radicals in neuronal cells and mitochondrial dysfunction, cell damage, and epilepsy. The positive stimulation of mitochondrial calcium signals by reactive oxygen species and increased reactive oxygen species generation resulting from increased mitochondrial calcium can lead to a positive feedback loop. We propose that calcium can pose both, physiological and pathological effects of mitochondrial function, which can lead in neuronal cell death and consequent epileptic seizures. Various antiepileptic drugs may impair the endogenous antioxidative ability to prevent oxidative stress. Therefore, some antiepileptic drugs, especially from the older generation, may trigger oxygen-dependent tissue injury. The prooxidative effects of these antiepileptic drugs might lead to enhancement of seizure activity, resulting in loss of their efficacy or apparent functional tolerance and undesired adverse effects. Additionally, various reactive metabolites of antiepileptic drugs are capable of covalent binding to macromolecules which may lead to deterioration of the epileptic seizures and systemic toxicity. Since neuronal loss seems to be one of the major neurobiological abnormalities in the epileptic brain, the ability of antioxidants to attenuate seizure generation and the accompanying changes in oxidative burden, further support an important role of antioxidants as having a putative antiepileptic potential.
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Affiliation(s)
| | | | - Tomaž Vovk
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia
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Effects of selenium and topiramate on cytosolic Ca(2+) influx and oxidative stress in neuronal PC12 cells. Neurochem Res 2012; 38:90-7. [PMID: 23011208 DOI: 10.1007/s11064-012-0893-z] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Revised: 09/10/2012] [Accepted: 09/13/2012] [Indexed: 10/27/2022]
Abstract
It has been widely suggested that selenium (Se) deficiency play an important role in the pathophysiology of epilepsy. It has been reported that Se provides protection against the neuronal damage in patients and animals with epilepsy by restoring the antioxidant defense mechanism. The neuroprotective effects of topiramate (TPM) have been reported in several studies but the putative mechanism of action remains elusive. We investigated effects of Se and TPM in neuronal PC12 cell by evaluating Ca(2+) mobilization, lipid peroxidation and antioxidant levels. PC12 cells were divided into eight groups namely control, TPM, Se, H(2)O(2), TPM + H(2)O(2), Se + H(2)O(2), Se + TPM and Se + TPM + H(2)O(2). The toxic doses and times of H(2)O(2), TPM and Se were determined by cell viability assay which is used to evaluate cell viability. Cells were incubated with 0.01 mM TPM for 5 h and 500 nM Se for 10 h. Then, the cells were exposed to 0.1 mM H(2)O(2) for 10 h before analysis. The cells in all groups except control, TPM and Se were exposed to H(2)O(2) for 15 min before analysis. Cytosolic Ca(2+) release and lipid peroxidation levels were higher in H(2)O(2) group than in control, Se and TPM combination groups although their levels were decreased by incubation of Se and TPM combination. However, there is no difference on Ca(2+) release in TPM group. Glutathione peroxidase activity, reduced glutathione and vitamin C levels in the cells were lower in H(2)O(2) group than in control, Se and TPM groups although their values were higher in the cells incubated with Se and TPM groups than in H(2)O(2) groups. In conclusion, these results indicate that Se induced protective effects on oxidative stress in PC12 cells by modulating cytosolic Ca(2+) influx and antioxidant levels. TPM modulated also lipid peroxidation and glutathione and vitamin C concentrations in the cell system.
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Thiol oxidation and altered NR2B/NMDA receptor functions in in vitro and in vivo pilocarpine models: implications for epileptogenesis. Neurobiol Dis 2012; 49:87-98. [PMID: 22824136 DOI: 10.1016/j.nbd.2012.07.013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2012] [Revised: 07/10/2012] [Accepted: 07/11/2012] [Indexed: 01/22/2023] Open
Abstract
Hippocampal sclerosis, the main pathological sign of chronic temporal lobe epilepsy (TLE), is associated with oxidative injury, altered N-methyl d-aspartate receptor (NMDAR) stoichiometry, and loss of hippocampal neurons. However, the mechanisms that drive the chronic progression of TLE remain elusive. Our previous studies have shown that NADPH oxidase activation and ERK 1/2 phosphorylation are required for the up-regulation of the predominantly pre-synaptic NR2B subunit auto-receptor in both in vitro and in vivo pilocarpine (PILO) models of TLE. To provide further understanding of the cellular responses during the early-stages of hyper excitability, we investigated the role of oxidative damage and altered NR2B functions. In rat primary hippocampal cultures, we found that N-acetylcysteine (NAC) prevented PILO-mediated thiol oxidation, apoptosis, cell death and NR2B subunit over-expression. Interestingly, NAC did not block thiol oxidation when added to the neurons 6h after the PILO exposure, suggesting that disulfide formation could rapidly become an irreversible phenomenon. Moreover, NAC pre-treatment did not prevent PILO-induced NR2A subunit over-expression, a critical event in hippocampal sclerosis. Pre-treatment with the highly specific NR2B subunit inhibitor, ifenprodil, partially decreased PILO-mediated thiol oxidation and was not effective in preventing apoptosis and cell death. However, if acutely administered 48h after PILO exposure, ifenprodil blocked glutamate-induced aberrant calcium influx, suggesting the crucial role of NR2B over-expression in triggering neuronal hyper-excitability. Furthermore, ifenprodil treatment was able to prevent NR2A subunit over-expression by means of ERK1/2 phosphorylation. Our findings indicate oxidative stress and NR2B/NMDA signaling as promising therapeutic targets for co-treatments aimed to prevent chronic epilepsy following the seizure onset.
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Tang W, Huang Z, Wang Y, Bo H, Fu P. Effect of Plasma Exchange on Hepatocyte Oxidative Stress, Mitochondria Function, and Apoptosis in Patients With Acute Fatty Liver of Pregnancy. Artif Organs 2012; 36:E39-47. [DOI: 10.1111/j.1525-1594.2011.01417.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Modulation of oxidative stress and mitochondrial function by the ketogenic diet. Epilepsy Res 2011; 100:295-303. [PMID: 22078747 DOI: 10.1016/j.eplepsyres.2011.09.021] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2011] [Revised: 08/17/2011] [Accepted: 09/07/2011] [Indexed: 12/23/2022]
Abstract
The ketogenic diet (KD) is a high-fat, low carbohydrate diet that is used as a therapy for intractable epilepsy. However, the mechanism(s) by which the KD achieves neuroprotection and/or seizure control are not yet known. The broad efficacy of the KD in diverse epilepsies coupled with its profound influence on metabolism suggests that mitochondrial functions may be critical in its mechanism(s) of seizure control. Mitochondria subserve important cellular functions that include the production of cellular ATP, control of apoptosis, maintenance of calcium homeostasis and the production and elimination of reactive oxygen species (ROS). This review will focus on recent literature reporting the regulation of mitochondrial functions and redox signaling by the KD. The review highlights a potential mechanism of the KD involving the production of low levels of redox signaling molecules such as H(2)O(2) and electrophiles e.g. 4-hydroxynonenal (4-HNE), which in turn activate adaptive pathways such as the protective transcription factor, NF E2-related factor 2 (Nrf2). This can ultimately result in increased production of antioxidants (e.g. GSH) and detoxification enzymes which may be critical in mediating the protective effects of the KD.
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Shin EJ, Jeong JH, Chung YH, Kim WK, Ko KH, Bach JH, Hong JS, Yoneda Y, Kim HC. Role of oxidative stress in epileptic seizures. Neurochem Int 2011; 59:122-37. [PMID: 21672578 PMCID: PMC3606551 DOI: 10.1016/j.neuint.2011.03.025] [Citation(s) in RCA: 294] [Impact Index Per Article: 22.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Revised: 03/27/2011] [Accepted: 03/28/2011] [Indexed: 11/16/2022]
Abstract
Oxidative stress resulting from excessive free-radical release is likely implicated in the initiation and progression of epilepsy. Therefore, antioxidant therapies aimed at reducing oxidative stress have received considerable attention in epilepsy treatment. However, much evidence suggests that oxidative stress does not always have the same pattern in all seizures models. Thus, this review provides an overview aimed at achieving a better understanding of this issue. We summarize work regarding seizure models (i.e., genetic rat models, kainic acid, pilocarpine, pentylenetetrazol, and trimethyltin), oxidative stress as an etiologic factor in epileptic seizures (i.e., impairment of antioxidant systems, mitochondrial dysfunction, involvement of redox-active metals, arachidonic acid pathway activation, and aging), and antioxidant strategies for seizure treatment. Combined, this review highlights pharmacological mechanisms associated with oxidative stress in epileptic seizures and the potential for neuroprotection in epilepsy that targets oxidative stress and is supported by effective antioxidant treatment.
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Affiliation(s)
- Eun-Joo Shin
- Neuropsychopharamcology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Ji Hoon Jeong
- Department of Pharmacology, College of Medicine, Chung-Ang University, Seoul 156-756, South Korea
| | - Yoon Hee Chung
- Department of Anatomy, College of Medicine, Chung-Ang University, Seoul 156-756, South Korea
| | - Won-Ki Kim
- Department of Neuroscience, College of Medicine, Korea University, Seoul 136-705, South Korea
| | - Kwang-Ho Ko
- Pharmacology Laboratory, College of Pharmacy, Seoul National University, Seoul 143-701, South Korea
| | - Jae-Hyung Bach
- Neuropsychopharamcology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
| | - Jau-Shyong Hong
- Neuropharmacology Section, Laboratory of Pharmacology and Chemistry, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA
| | - Yukio Yoneda
- Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School of Natural Science and Technology, Kanazawa, Ishikawa 920-1192, Japan
| | - Hyoung-Chun Kim
- Neuropsychopharamcology and Toxicology Program, College of Pharmacy, Kangwon National University, Chunchon 200-701, South Korea
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Prigol M, Brüning CA, Nogueira CW, Zeni G. The role of the glutathione system in seizures induced by diphenyl diselenide in rat pups. Chem Biol Interact 2011; 193:65-70. [DOI: 10.1016/j.cbi.2011.05.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Revised: 05/09/2011] [Accepted: 05/11/2011] [Indexed: 11/29/2022]
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The neuroprotective effect of curcumin and Nigella sativa oil against oxidative stress in the pilocarpine model of epilepsy: a comparison with valproate. Neurochem Res 2011; 36:2195-204. [PMID: 21751034 DOI: 10.1007/s11064-011-0544-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/02/2011] [Indexed: 12/18/2022]
Abstract
Oxidative stress has been implicated to play a role in epileptogenesis and pilocarpine-induced seizures. The present study aims to evaluate the antioxidant effects of curcumin, Nigella sativa oil (NSO) and valproate on the levels of malondialdehyde, nitric oxide, reduced glutathione and the activities of catalase, Na⁺, K⁺-ATPase and acetylcholinesterase in the hippocampus of pilocarpine-treated rats. The animal model of epilepsy was induced by pilocarpine and left for 22 days to establish the chronic phase of epilepsy. These animals were then treated with curcumin, NSO or valproate for 21 days. The data revealed evidence of oxidative stress in the hippocampus of pilocarpinized rats as indicated by the increased nitric oxide levels and the decreased glutathione levels and catalase activity. Moreover, a decrease in Na⁺, K⁺-ATPase activity and an increase in acetylcholinesterase activity occurred in the hippocampus after pilocarpine. Treatment with curcumin, NSO or valproate ameliorated most of the changes induced by pilocarpine and restored Na⁺, K⁺-ATPase activity in the hippocampus to control levels. This study reflects the promising anticonvulsant and potent antioxidant effects of curcumin and NSO in reducing oxidative stress, excitability and the induction of seizures in epileptic animals and improving some of the adverse effects of antiepileptic drugs.
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Folbergrová J, Kunz WS. Mitochondrial dysfunction in epilepsy. Mitochondrion 2011; 12:35-40. [PMID: 21530687 DOI: 10.1016/j.mito.2011.04.004] [Citation(s) in RCA: 104] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Revised: 02/16/2011] [Accepted: 04/14/2011] [Indexed: 11/29/2022]
Abstract
Mitochondrial dysfunction has been identified as one potential cause of epileptic seizures. Impaired mitochondrial function has been reported for the seizure focus of patients with temporal lobe epilepsy and Ammon's horn sclerosis and of adult and immature animal models of epilepsy. Since mitochondrial oxidative phosphorylation provides the major source of ATP in neurons and mitochondria participate in cellular Ca(2+) homeostasis and generation of reactive oxygen species, their dysfunction strongly affects neuronal excitability and synaptic transmission. Therefore, mitochondrial dysfunction is proposed to be highly relevant for seizure generation. Additionally, mitochondrial dysfunction is known to trigger neuronal cell death, which is a prominent feature of therapy-resistant epilepsy. For this reason mitochondria have to be considered as promising targets for neuroprotective strategies in epilepsy.
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Affiliation(s)
- Jaroslava Folbergrová
- Department of Developmental Epileptology, Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Chen SD, Chang AYW, Chuang YC. The potential role of mitochondrial dysfunction in seizure-associated cell death in the hippocampus and epileptogenesis. J Bioenerg Biomembr 2011; 42:461-5. [PMID: 21153870 DOI: 10.1007/s10863-010-9321-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Epilepsy is considered one of the most common neurological disorders worldwide. The burst firing neurons associated with prolonged epileptic discharges could lead to a large number of changes with events of cascades at the cellular level. From its role as the cellular powerhouse, mitochondria also play a crucial role in the mechanisms of cell death. Emerging evidence has shown that prolonged seizures may result in mitochondrial dysfunction and increase of oxidative and nitrosative stress in the hippocampus that precede neuronal cell death and cause subsequent epileptogenesis. The selective dysfunction of mitochondrial respiratory chain Complex I has been suggested to be a biochemical hallmark of seizure-induced neuronal cell death and epileptogenesis. Therefore, protection of mitochondria from bioenergetic failure and oxidative stress in the hippocampus may open a new vista to the development of effective neuroprotective strategies against seizure-induced brain damage and to the design of novel treatment perspectives against therapy-resistant forms of epilepsy.
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Affiliation(s)
- Shang-Der Chen
- Department of Neurology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Chang Gung University College of Medicine, Kaohsiung, Taiwan
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Waldbaum S, Patel M. Mitochondrial dysfunction and oxidative stress: a contributing link to acquired epilepsy? J Bioenerg Biomembr 2011; 42:449-55. [PMID: 21132357 DOI: 10.1007/s10863-010-9320-9] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Mitochondrial dysfunction and oxidative stress contribute to several neurologic disorders and have recently been implicated in acquired epilepsies such as temporal lobe epilepsy (TLE). Acquired epilepsy is typically initiated by a brain injury followed by a "latent period" whereby molecular, biochemical and other cellular alterations occur in the brain leading to chronic epilepsy. Mitochondrial dysfunction and oxidative stress are emerging as factors that not only occur acutely as a result of precipitating injuries such as status epilepticus (SE), but may also contribute to epileptogenesis and chronic epilepsy. Mitochondria are the primary site of reactive oxygen species (ROS) making them uniquely vulnerable to oxidative damage that may affect neuronal excitability and seizure susceptibility. This mini-review provides an overview of evidence suggesting the role of mitochondrial dysfunction and oxidative stress as acute consequences of injuries that are known to incite chronic epilepsy and their involvement in the chronic stages of acquired epilepsy.
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Affiliation(s)
- Simon Waldbaum
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado Denver Anschutz Medical Campus, 12700 East 19th Avenue, Aurora, CO 80045, USA
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Waldbaum S, Liang LP, Patel M. Persistent impairment of mitochondrial and tissue redox status during lithium-pilocarpine-induced epileptogenesis. J Neurochem 2010; 115:1172-82. [PMID: 21219330 DOI: 10.1111/j.1471-4159.2010.07013.x] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Mitochondrial dysfunction and oxidative stress are known to occur following acute seizure activity but their contribution during epileptogenesis is largely unknown. The goal of this study was to determine the extent of mitochondrial oxidative stress, changes to redox status, and mitochondrial DNA (mtDNA) damage during epileptogenesis in the lithium-pilocarpine model of temporal lobe epilepsy. Mitochondrial oxidative stress, changes in tissue and mitochondrial redox status, and mtDNA damage were assessed in the hippocampus and neocortex of Sprague-Dawley rats at time points (24h to 3months) following lithium-pilocarpine administration. A time-dependent increase in mitochondrial hydrogen peroxide (H(2)O(2)) production coincident with increased mtDNA lesion frequency in the hippocampus was observed during epileptogenesis. Acute increases (24-48h) in H(2)O(2) production and mtDNA lesion frequency were dependent on the severity of convulsive seizure activity during initial status epilepticus. Tissue levels of GSH, GSH/GSSG, coenzyme A (CoASH), and CoASH/CoASSG were persistently impaired at all measured time points throughout epileptogenesis, that is, acutely (24-48h), during the 'latent period' (48h to 7days), and chronic epilepsy (21days to 3months). Together with our previous work, these results demonstrate the model independence of mitochondrial oxidative stress, genomic instability, and persistent impairment of mitochondrial specific redox status during epileptogenesis. Lasting impairment of mitochondrial and tissue redox status during the latent period, in addition to the acute and chronic phases of epileptogenesis, suggests that redox-dependent processes may contribute to the progression of epileptogenesis in experimental temporal lobe epilepsy.
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Affiliation(s)
- Simon Waldbaum
- Department of Pharmaceutical Sciences, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, USA
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Early hippocampal oxidative stress is a direct consequence of seizures in the rapid electrical amygdala kindling model. Epilepsy Res 2010; 90:285-94. [DOI: 10.1016/j.eplepsyres.2010.06.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/18/2010] [Accepted: 06/10/2010] [Indexed: 11/23/2022]
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de Sales Santos ÍM, da Rocha Tomé A, Feitosa CM, de Souza GF, Feng D, de Freitas RM, Jordán J. Lipoic acid blocks seizures induced by pilocarpine via increases in δ-aminolevulinic dehydratase and Na+, K+-ATPase activity in rat brain. Pharmacol Biochem Behav 2010; 95:88-91. [DOI: 10.1016/j.pbb.2009.12.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2009] [Revised: 12/01/2009] [Accepted: 12/14/2009] [Indexed: 11/29/2022]
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Waldbaum S, Patel M. Mitochondria, oxidative stress, and temporal lobe epilepsy. Epilepsy Res 2010; 88:23-45. [PMID: 19850449 PMCID: PMC3236664 DOI: 10.1016/j.eplepsyres.2009.09.020] [Citation(s) in RCA: 207] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 09/18/2009] [Accepted: 09/22/2009] [Indexed: 10/20/2022]
Abstract
Mitochondrial oxidative stress and dysfunction are contributing factors to various neurological disorders. Recently, there has been increasing evidence supporting the association between mitochondrial oxidative stress and epilepsy. Although certain inherited epilepsies are associated with mitochondrial dysfunction, little is known about its role in acquired epilepsies such as temporal lobe epilepsy (TLE). Mitochondrial oxidative stress and dysfunction are emerging as key factors that not only result from seizures, but may also contribute to epileptogenesis. The occurrence of epilepsy increases with age, and mitochondrial oxidative stress is a leading mechanism of aging and age-related degenerative disease, suggesting a further involvement of mitochondrial dysfunction in seizure generation. Mitochondria have critical cellular functions that influence neuronal excitability including production of adenosine triphosphate (ATP), fatty acid oxidation, control of apoptosis and necrosis, regulation of amino acid cycling, neurotransmitter biosynthesis, and regulation of cytosolic Ca(2+) homeostasis. Mitochondria are the primary site of reactive oxygen species (ROS) production making them uniquely vulnerable to oxidative stress and damage which can further affect cellular macromolecule function, the ability of the electron transport chain to produce ATP, antioxidant defenses, mitochondrial DNA stability, and synaptic glutamate homeostasis. Oxidative damage to one or more of these cellular targets may affect neuronal excitability and increase seizure susceptibility. The specific targeting of mitochondrial oxidative stress, dysfunction, and bioenergetics with pharmacological and non-pharmacological treatments may be a novel avenue for attenuating epileptogenesis.
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Affiliation(s)
- Simon Waldbaum
- Department of Pharmaceutical Sciences University of Colorado Denver School of Pharmacy Aurora, CO 80045 U.S.A
| | - Manisha Patel
- Department of Pharmaceutical Sciences University of Colorado Denver School of Pharmacy Aurora, CO 80045 U.S.A
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Sustained deficiency of mitochondrial complex I activity during long periods of survival after seizures induced in immature rats by homocysteic acid. Neurochem Int 2009; 56:394-403. [PMID: 19931336 DOI: 10.1016/j.neuint.2009.11.011] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Revised: 11/10/2009] [Accepted: 11/12/2009] [Indexed: 01/25/2023]
Abstract
Our previous work demonstrated the marked decrease of mitochondrial complex I activity in the cerebral cortex of immature rats during the acute phase of seizures induced by bilateral intracerebroventricular infusion of dl-homocysteic acid (600 nmol/side) and at short time following these seizures. The present study demonstrates that the marked decrease ( approximately 60%) of mitochondrial complex I activity persists during the long periods of survival, up to 5 weeks, following these seizures, i.e. periods corresponding to the development of spontaneous seizures (epileptogenesis) in this model of seizures. The decrease was selective for complex I and it was not associated with changes in the size of the assembled complex I or with changes in mitochondrial content of complex I. Inhibition of complex I was accompanied by a parallel, up to 5 weeks lasting significant increase (15-30%) of three independent mitochondrial markers of oxidative damage, 3-nitrotyrosine, 4-hydroxynonenal and protein carbonyls. This suggests that oxidative modification may be most likely responsible for the sustained deficiency of complex I activity although potential role of other factors cannot be excluded. Pronounced inhibition of complex I was not accompanied by impaired ATP production, apparently due to excess capacity of complex I documented by energy thresholds. The decrease of complex I activity was substantially reduced by treatment with selected free radical scavengers. It could also be attenuated by pretreatment with (S)-3,4-DCPG (an agonist for subtype 8 of group III metabotropic glutamate receptors) which had also a partial antiepileptogenic effect. It can be assumed that the persisting inhibition of complex I may lead to the enhanced production of reactive oxygen and/or nitrogen species, contributing not only to neuronal injury demonstrated in this model of seizures but also to epileptogenesis.
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Lipoic acid alters delta-aminolevulinic dehydratase, glutathione peroxidase and Na+,K+-ATPase activities and glutathione-reduced levels in rat hippocampus after pilocarpine-induced seizures. Cell Mol Neurobiol 2009; 30:381-7. [PMID: 19798568 DOI: 10.1007/s10571-009-9460-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2009] [Accepted: 09/15/2009] [Indexed: 12/18/2022]
Abstract
In the present study, we investigated the effects of lipoic acid (LA) in the brain oxidative stress caused by pilocarpine-induced seizures in adult rats. Wistar rats were treated with 0.9% saline (i.p., control group), lipoic acid (10 mg/kg, i.p., LA group), pilocarpine (400 mg/kg, i.p., pilocarpine group), and the association of LA (10 mg/kg, i.p.) plus pilocarpine (400 mg/kg, i.p.), 30 min before the administration of LA (LA plus pilocarpine group). After the treatments, all groups were observed for 1 h. The enzyme activities [delta-aminolevulinic dehydratase (delta-ALA-D), glutathione peroxidase (GPx), glutathione reductase (GR), and Na+,K+-ATPase] as well as the glutathione-reduced (GSH) and ascorbic acid (AA) concentrations were measured using spectrophotometric methods, and the results were compared to values obtained from saline and pilocarpine-treated animals. Protective effects of LA were also evaluated on the same parameters. In pilocarpine group, no changes were observed in GPx and GR activities and AA content. Moreover, in the same group, decrease in GSH levels as well as a reduction in delta-ALA-D and Na+,K+-ATPase activities after seizures was observed. In turn, in LA plus pilocarpine group, the appearance of seizures was abolished, and the decreases in delta-ALA-D and Na+,K+-ATPase activities produced by seizures as well as increases in GSH levels and GPx activity were reversed, when compared to the pilocarpine seizing group. The results of the present study demonstrated that preadministration of LA abolished seizure episodes induced by pilocarpine in rat, probably by reducing oxidative stress in rat hippocampus caused by seizures.
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Davis LM, Rho JM, Sullivan PG. UCP-mediated free fatty acid uncoupling of isolated cortical mitochondria from fasted animals: correlations to dietary modulations. Epilepsia 2009; 49 Suppl 8:117-9. [PMID: 19049607 DOI: 10.1111/j.1528-1167.2008.01854.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Uncoupling proteins (UCP) translocate protons from the mitochondrial intermembrane space to the matrix, thereby "uncoupling" electron transport from the production of ATP. It has been shown that these proteins are highly expressed in animals maintained on the ketogenic diet (KD). Although the exact mechanism remains unclear, it is known that these proteins are activated within a protective antireactive oxygen species (ROS) mechanism by free fatty acids (FFA). In our current studies, mitochondrial samples were probed for the presence of UCP2, which is the most ubiquitously expressed UCP isoform. We found that both traumatic brain injury and fasting upregulated the expression of UCP2, with a synergistic upregulation in fasted injured animals. We then used mitochondria from fasted naive animals to screen a number of FFA for their activation of uncoupling as well as their ability to reduce ROS. We found that arachidonic acid (AA), docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA), palmitoleic acid, myristic acid, and butyric acid increased mitochondrial uncoupling when added after oligomycin. These FFA, along with oleic acid, also reduced ROS in mitochondria incubated with oligomycin. In order to correlate our data to KD and fasting, both of which have been shown to be neuroprotective after neurologic insult, we determined the serum levels of FFA in KD and fasted animals using gas chromatography/mass spectroscopy. We also determined brain and cerebrospinal fluid (CSF) FFA levels from fasted animals.
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Affiliation(s)
- Laurie M Davis
- Spinal Cord and Brain Injury Research Center, University of Kentucky, Lexington, Kentucky, USA
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Affiliation(s)
- Hannah Cock
- Epilepsy Group, Department of Cardiac and Vascular Sciences, St. Georges, University of London and Atkinson Morley Regional Neuroscience Centre, St. Georges Hospital, London, United Kingdom.
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Jarrett SG, Liang LP, Hellier JL, Staley KJ, Patel M. Mitochondrial DNA damage and impaired base excision repair during epileptogenesis. Neurobiol Dis 2008; 30:130-8. [PMID: 18295498 DOI: 10.1016/j.nbd.2007.12.009] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2007] [Revised: 12/16/2007] [Accepted: 12/21/2007] [Indexed: 11/24/2022] Open
Abstract
Oxidative stress and mitochondrial dysfunction are acute consequences of status epilepticus (SE). However, the role of mitochondrial oxidative stress and genomic instability during epileptogenesis remains unknown. Using the kainate animal model of temporal lobe epilepsy, we investigated oxidative mitochondrial DNA (mtDNA) damage and changes in the mitochondrial base excision repair pathway (mtBER) in the rat hippocampus for a period of 3 months after SE. Acute seizure activity caused a time-dependent increase in mitochondrial, but not nuclear 8-hydroxy-2-deoxyguanosine (8-OHdG/2dG) levels and a greater frequency of mtDNA lesions. This was accompanied by increased mitochondrial H2O2 production and a transient decrease in mtDNA repair capacity. The mtBER proteins 8-oxoguanine glycosylase (Ogg1) and DNA polymerase gamma (Pol gamma) demonstrated elevated expression at mRNA and protein levels shortly after SE and this was followed by a gradual improvement in mtDNA repair capacity. Recurrent seizures associated with the chronic phase of epilepsy coincided with the accumulation of mtDNA damage, increased mitochondrial H2O2 levels, decreased expression of Ogg1 and Pol gamma and impaired mtDNA repair capacity. Together, increased oxidative mtDNA damage, mitochondrial H2O2 production and alterations in the mtBER pathway provide evidence for mitochondrial oxidative stress in epilepsy and suggest that mitochondrial injury may contribute to epileptogenesis.
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Affiliation(s)
- Stuart G Jarrett
- Department of Pharmaceutical Sciences, University of Colorado Health Sciences Center, 4200 East Ninth Avenue, Denver, CO 80262, USA
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Abstract
The mechanisms underlying the development of drug resistance in epilepsy are complex and, at this time, not fully understood. It is widely accepted that the efficacy of an antiepileptic drug (AED) is determined by its ability to cross the blood-brain barrier (BBB) and bind to intraparenchymal target sites. According to the target hypothesis, pharmacoresistance occurs when target sites are structurally and/or functionally modified in such a way that they become less sensitive to AEDs. A large number of targets for AEDs have been identified in the brain, many of which undergo molecular changes during chronic epilepsy. So far, a reduced sensitivity of drug targets to AEDs in chronic human and experimental epilepsy has been suggested for the voltage-gated Na(+) channel and the GABA(A) receptor. At the molecular level, altered drug targets may arise due to the transcriptional regulation of ion channel subunit genes. Alternatively, ion channel subunits may be modified by redox modulation or phosphorylation, a set of mechanisms that may be invoked much more rapidly than transcriptional changes. In addition to functional experiments, genetic studies are currently attempting to identify polymorphisms that are specifically associated with the functional phenotypes of drug resistance and drug responsiveness in the epileptic population. It is hoped that our increased understanding of the target mechanisms underlying pharmacoresistance will lead to the development of novel therapeutic strategies that will improve treatment outcomes in individuals with refractory epilepsy.
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Affiliation(s)
- Heinz Beck
- Department of Epileptology, University of Bonn, Bonn, Germany.
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Folbergrová J, Jesina P, Drahota Z, Lisý V, Haugvicová R, Vojtísková A, Houstĕk J. Mitochondrial complex I inhibition in cerebral cortex of immature rats following homocysteic acid-induced seizures. Exp Neurol 2007; 204:597-609. [PMID: 17270175 DOI: 10.1016/j.expneurol.2006.12.010] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 11/13/2006] [Accepted: 12/11/2006] [Indexed: 12/27/2022]
Abstract
The major finding of the present study concerns the marked decrease of respiratory chain complex I activity in the cerebral cortex of immature rats following seizures induced by bilateral intracerebroventricular infusion of dl-homocysteic acid (600 nmol/side). This decrease was already evident during the acute phase of seizures (60-90 min after infusion) and persisted for at least 20 h after the seizures. It was selective for complex I since activities of complex II and IV and citrate synthase remained unaffected. Inhibition of complex I activity was not associated with changes in complex I content. Based on enhanced lipoperoxidation and decreased aconitase activity, it can be postulated that oxidative modification is most likely responsible for the observed inhibition. Mitochondrial respiration, as well as cortical ATP levels remained in the control range, apparently due to excess capacity of the complex I documented by energy thresholds. On the other hand, the enhanced production of reactive oxygen species by inhibited complex I was observed in mitochondria from HCA-treated animals. The decrease of complex I activity was substantially attenuated when animals were treated with substances providing an anticonvulsant effect and also with selected free radical scavengers. We can assume that inhibition of complex I may elicit enhanced formation of reactive oxygen species and contribute thus to neuronal injury demonstrated in this model.
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Affiliation(s)
- Jaroslava Folbergrová
- Institute of Physiology, Academy of Sciences of the Czech Republic, Vídenská 1083, 142 20 Prague 4, Czech Republic.
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Gibbs JE, Cock HR. Administration of Levetiracetam after prolonged status epilepticus does not protect from mitochondrial dysfunction in a rodent model. Epilepsy Res 2007; 73:208-12. [PMID: 17085017 DOI: 10.1016/j.eplepsyres.2006.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Revised: 09/12/2006] [Accepted: 09/24/2006] [Indexed: 11/17/2022]
Abstract
Neuronal death and dysfunction occur after status epilepticus (SE), and is associated with mitochondrial enzyme damage. We previously showed, using the rat perforant pathway stimulation model, that levetiracetam administration (LEV; 1000 mg/kg intraperitoneal) during established SE reduces seizure severity and prevents mitochondrial dysfunction. We now show that administration of the same dose of LEV after 5h SE, does not protect from mitochondrial dysfunction.
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Affiliation(s)
- J E Gibbs
- Epilepsy Group, Centre for Clinical Neurosciences, St. George's University of London, Cranmer Terrace, Tooting, London SW17 0RE, United Kingdom
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Sleven HJ, Gibbs JE, Cock HR. The antioxidant N-acetyl-L-cysteine does not prevent hippocampal glutathione loss or mitochondrial dysfunction associated with status epilepticus. Epilepsy Res 2006; 69:165-9. [PMID: 16490347 DOI: 10.1016/j.eplepsyres.2006.01.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2005] [Revised: 01/16/2006] [Accepted: 01/17/2006] [Indexed: 10/25/2022]
Abstract
Hippocampal reduced glutathione (GSH) levels diminish after status epilepticus (SE), which precedes damage to mitochondrial enzymes, which is associated with cell death. The rat perforant pathway stimulation model was used to assess whether intraperitoneal administration of the GSH precursor N-acetyl-L-cysteine (NAC) protected against these changes. NAC (300 mg/kg) treated animals exhibited the same GSH decrease post SE as vehicle treated. Furthermore, NAC treatment had no protective effects on mitochondrial dysfunction.
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Affiliation(s)
- H J Sleven
- Epilepsy Group, Centre for Clinical Neurosciences, St. Georges, University of London, Cranmer Terrace, Tooting, London SE1 0RE, UK
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