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Soluble epoxide hydrolase activity regulates inflammatory responses and seizure generation in two mouse models of temporal lobe epilepsy. Brain Behav Immun 2015; 43:118-29. [PMID: 25135858 DOI: 10.1016/j.bbi.2014.07.016] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Revised: 07/15/2014] [Accepted: 07/28/2014] [Indexed: 12/31/2022] Open
Abstract
Neuroinflammation is known to be involved in epileptogenesis with unclear mechanisms. Inhibition of soluble epoxide hydrolase (sEH) seems to offer anti-inflammatory protection to ischemic brain injury in rodents. Thus, it is hypothesized that sEH inhibition might also affect the neuroinflammatory responses caused by epileptic seizures. In the present study, we investigated the involvement of sEH in neuroinflammation, seizure generation and subsequent epileptogenesis using two mouse models of temporal lobe epilepsy. Experimental epileptic seizures were induced by either pilocarpine or electrical amygdala kindling in both wild-type (WT) C57BL/6 mice and sEH knockout (sEH KO) mice. The sEH expression in the hippocampus was detected by immunohistochemistry and Western blot analysis. The effects of the sEH hydrolase inhibitors, 12-(3-adamantan-1-yl-ureido)-dodecanoic acid (AUDA) and N-[1-(1-oxopropyl)-4-piperidinyl]-N'-[4-(trifluoromethoxy) phenyl)-urea (TPPU), and of the genetic deletion of sEH on seizure-induced neuroinflammatory responses and the development of epilepsy were evaluated. In the hippocampus of WT mice, sEH was mainly expressed in astrocytes (GFAP(+)), neurons (NeuN(+)) and scattered microglia (Iba-1(+)) in the regions of CA1, CA3 and dentate gyrus. Expression of sEH was significantly increased on day 7, 14, 21 and 28 after pilocarpine-induced status epilepticus (SE). Administration with sEH inhibitors attenuated the SE-induced up-regulation of interleukin-1β (IL-1β) and interleukin-6 (IL-6), the degradation of EETs, as well as IκB phosphorylation. Following treatment with AUDA, the frequency and duration of spontaneous motor seizures in the pilocarpine-SE mice were decreased and the seizure-induction threshold of the fully kindled mice was increased. Up-regulation of hippocampal IL-1β and IL-6 was found in both WT and sEH KO mice after successful induction of SE. Notably, sEH KO mice were more susceptible to seizures than WT mice. Seizure related neuroinflammation and ictogenesis were attenuated by pharmacological inhibition of sEH enzymatic activity but not by sEH genetic deletion. Therefore, sEH may play an important role in the generation of epilepsy. Furthermore, the effectiveness of AUDA in terms of anti-inflammatory and anti-ictogenesis properties suggests that it may have clinical therapeutic implication for epilepsy in the future, particularly when treating temporal lobe epilepsy.
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Wang H, Liu S, Tang Z, Liu J. Some cross-talks between immune cells and epilepsy should not be forgotten. Neurol Sci 2014; 35:1843-9. [PMID: 25253631 DOI: 10.1007/s10072-014-1955-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 09/14/2014] [Indexed: 11/25/2022]
Abstract
Recent studies have reported that immune cells were not always found in brain specimens from epileptic patients, then should we stop investigating the relationship between these cells and epilepsy? The answer is no! In addition to immunocyte infiltration in brain parenchyma, a flurry of papers have demonstrated that there were significant alterations in peripheral blood cells (PBCs) immediately after seizure onset, especially changes in some specific transporters of neurotransmitters expressed on the membrane of immunocyte. These transporters may regulate neuronal excitability in mature neurons. Besides, many researchers did find activated leukocytes adhered to the endothelium of blood brain barrier or infiltrated into the brain parenchyma in several types of epilepsy both in human and animal studies; moreover, it is worth noting that different immune cells play different roles in epilepsy development, which was indicated by in vitro and in vivo evidence. This review is going to summarize available evidence supporting changes in PBCs after seizures, and will also focus on some specific effects of immune cells on epilepsy development.
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Affiliation(s)
- Hong Wang
- Dalian Municipal Central Hospital, No. 2 VIP Ward, Shahekou District, Dalian, 116000, Liaoning Province, China
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53
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Varvel NH, Jiang J, Dingledine R. Candidate drug targets for prevention or modification of epilepsy. Annu Rev Pharmacol Toxicol 2014; 55:229-47. [PMID: 25196047 DOI: 10.1146/annurev-pharmtox-010814-124607] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epilepsy is a prevalent neurological disorder afflicting nearly 50 million people worldwide. The disorder is characterized clinically by recurrent spontaneous seizures attributed to abnormal synchrony of brain neurons. Despite advances in the treatment of epilepsy, nearly one-third of patients are resistant to current therapies, and the underlying mechanisms whereby a healthy brain becomes epileptic remain unresolved. Therefore, researchers have a major impetus to identify and exploit new drug targets. Here we distinguish between epileptic effectors, or proteins that set the seizure threshold, and epileptogenic mediators, which control the expression or functional state of the effector proteins. Under this framework, we then discuss attempts to regulate the mediators to control epilepsy. Further insights into the complex processes that render the brain susceptible to seizures and the identification of novel mediators of these processes will lead the way to the development of drugs to modify disease outcome and, potentially, to prevent epileptogenesis.
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Affiliation(s)
- Nicholas H Varvel
- Department of Pharmacology, Emory University School of Medicine, Atlanta, Georgia 30322;
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54
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Kir HM, Sahin D, Oztaş B, Musul M, Kuskay S. Effects of single-dose neuropeptide Y on levels of hippocampal BDNF, MDA, GSH, and NO in a rat model of pentylenetetrazole-induced epileptic seizure. Bosn J Basic Med Sci 2014; 13:242-7. [PMID: 24289760 DOI: 10.17305/bjbms.2013.2332] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Epilepsy is one of the most common neurological disorders, characterized by recurrent seizures, which may increase the content of reactive oxygen and nitrogen species. The objective of this study was to investigate the effects of Neuropeptide Y on oxidative and nitrosative balance and brain-derived neurotrophic factor levels induced by pentylenetetrazole (a standard convulsant drug) in the hippocampus of Wistar rats. Three groups of seven rats were treated intraperitoneally as follows: group 1 (saline + saline) 1 ml saline, group 2 (salin + Pentylenetetrazole) 1 ml saline 30 min before Pentylenetetrazole; and group 3 (Neuropeptide Y + Pentylenetetrazole) 60 μg/kg Neuropeptide Y 30 min before 60 mg/kg Pentylenetetrazole. After 24 h, the animals were euthanized by decapitation. Hippocampus were isolated to evaluate the malondialdehyde, glutathione, nitric oxide, and brain-derived neurotrophic factor levels in three rat groups. The results of this study demonstrated that while intraperitoneally administered neuropeptide Y did not result in a statistically significant difference in BDNF levels, its administration caused a statistically significant decrease in malondialdehyde and nitric oxide levels and an increase in glutathione levels in rats with pentylenetetrazole-induced epileptic seizure. Neuropeptide Y were able to reduce nitroxidative damage induced by pentylenetetrazole in the hippocampus of Wistar rats.
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Affiliation(s)
- Hale Maral Kir
- Department of Biochemistry, School of Medicine, Kocaeli University, Umuttepe Kampusu, 41380, Kocaeli, Turkey
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55
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Emsley HC, Appleton RE, Whitmore CL, Jury F, Lamb JA, Martin JE, Ollier WE, de la Morandière KP, Southern KW, Allan SM. Variations in inflammation-related genes may be associated with childhood febrile seizure susceptibility. Seizure 2014; 23:457-61. [DOI: 10.1016/j.seizure.2014.03.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Revised: 03/04/2014] [Accepted: 03/06/2014] [Indexed: 11/24/2022] Open
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56
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YE FEI, CHEN XUQIN, BAO GUANSHUI, HUA YIN, WANG ZHEDONG, BAO YICHUAN. Effect of topiramate on interleukin 6 expression in the hippocampus of amygdala-kindled epileptic rats. Exp Ther Med 2014; 7:223-227. [PMID: 24348794 PMCID: PMC3860984 DOI: 10.3892/etm.2013.1396] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 10/16/2013] [Indexed: 11/26/2022] Open
Abstract
The objective of this study was to analyze the changes in expression and the possible functions of interleukin-6 (IL-6) in electrical kindling of the basolateral amygdala (BLA) in epileptic rats. Bipolar electrodes were implanted into the BLA of Sprague-Dawley rats, and the rats were then subjected to chronic electrical stimulation through the electrodes to induce kindling. The seizure characteristics and behavioral changes of the rats were observed, and electroencephalograms were recorded during and following kindling. The IL-6 mRNA expression in the hippocampi of the rats was analyzed using semi-quantitative reverse transcription-polymerase chain reaction, and control and topiramate (TPM)-treated groups were compared. The mean time-period required for kindling was 13.50±3.99 days, and the afterdischarge duration (ADD) measured between 21,450 and 119,720 msec. The expression of IL-6 mRNA was significantly upregulated in the kindled rats. TPM was able to depress the seizures and decrease the IL-6 level in the kindled rats. In conclusion, IL-6 mRNA was upregulated in the hippocampi of epileptic rats, and IL-6 may have participated in the process of kindling.
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Affiliation(s)
- FEI YE
- Department of Neurology, Jinhua Municipal Central Hospital, Jinhua, Zhejiang 321000, P.R. China
| | - XU-QIN CHEN
- Department of Neurology, Affiliated Children’s Hospital of Soochow University, Suzhou, Jiangsu 215000, P.R. China
| | - GUAN-SHUI BAO
- Department of Neurology, No.3 People’s Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 201900, P.R. China
| | - YIN HUA
- Department of Child Neurology, Wuxi People’s Hospital, Wuxi, Jiangsu 214001, P.R. China
| | - ZHE-DONG WANG
- Department of Neurology, Affiliated Children’s Hospital of Soochow University, Suzhou, Jiangsu 215000, P.R. China
| | - YI-CHUAN BAO
- Xi’an Jiaotong-Liverpool University, Suzhou, Jiangsu 215123, P.R. China
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57
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Durmus H, Kurtuncu M, Tuzun E, Pehlivan M, Akman-Demir G, Yapıcı Z, Eraksoy M. Comparative clinical characteristics of early- and adult-onset multiple sclerosis patients with seizures. Acta Neurol Belg 2013; 113:421-6. [PMID: 23696071 DOI: 10.1007/s13760-013-0210-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 05/13/2013] [Indexed: 01/29/2023]
Abstract
Multiple sclerosis (MS) and epilepsy are common disorders, the co-occurrence of which has been of considerable interest. This study aimed to evaluate the prevalence and clinical features of epileptic seizures in patients with definite MS including those with pediatric onset (≤16 years of age). Out of 2,300 patients with definite MS followed in our outpatient clinic, 36 with epileptic seizures were identified. In this cohort, 8 out of 146 pediatric cases had seizures. The clinical and demographic features of the patients were recorded. Multiple logistic regression model with the occurence of seizures as the dependent variable was performed to identify the risk factors for seizure occurrence in MS patients. The prevalence of epileptic seizures was 1.5% in definite MS patients, 1.3% in adult-onset (comparable to seizure prevalence in the general population) and 5.5% in pediatric MS patients (≤16 years old). Twenty-six of 36 (72%) patients with MS and epilepsy developed recurrent seizures after the first epileptic seizure. Mean annual relapse rate (p ≤ 0.001), mean expanded disability status scale (EDSS) score (p = 0.004) and the ratio of patients with pediatric onset (p = 0.01) were higher in MS patients with seizures. In the multiple logistic regression analysis, age at MS onset and EDSS at the last examination were found to be predictors of seizure occurrence. Occurrence of seizures during the clinical course of MS appears to be associated with early-onset and increased disease severity and might be coincidental in adults.
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Affiliation(s)
- Hacer Durmus
- Department of Neurology, Faculty of Medicine, Istanbul University, Çapa, 34390, Istanbul, Turkey
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58
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Martínez-Lazcano JC, González-Guevara E, del Carmen Rubio M, Franco-Pérez J, Custodio V, Hernández-Cerón M, Livera C, Paz C. The effects of ozone exposure and associated injury mechanisms on the central nervous system. Rev Neurosci 2013; 24:337-52. [PMID: 23585211 DOI: 10.1515/revneuro-2012-0084] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Accepted: 02/25/2013] [Indexed: 12/27/2022]
Abstract
Ozone (O3) is a component of photochemical smog, which is a major air pollutant and demonstrates properties that are harmful to health because of the toxic properties that are inherent to its powerful oxidizing capabilities. Environmental O3 exposure is associated with many symptoms related to respiratory disorders, which include loss of lung function, exacerbation of asthma, airway damage, and lung inflammation. The effects of O3 are not restricted to the respiratory system or function - adverse effects within the central nervous system (CNS) such as decreased cognitive response, decrease in motor activity, headaches, disturbances in the sleep-wake cycle, neuronal dysfunctions, cell degeneration, and neurochemical alterations have also been described; furthermore, it has also been proposed that O3 could have epigenetic effects. O3 exposure induces the reactive chemical species in the lungs, but the short half-life of these chemical species has led some authors to attribute the injurious mechanisms observed within the lungs to inflammatory processes. However, the damage to the CNS induced by O3 exposure is not well understood. In this review, the basic mechanisms of inflammation and activation of the immune system by O3 exposure are described and the potential mechanisms of damage, which include neuroinflammation and oxidative stress, and the signs and symptoms of disturbances within the CNS caused by environmental O3 exposure are discussed.
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59
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Ferrazoli EG, Blanco MM, Bittencourt S, Bachi ALL, Bahia L, Soares MBP, Ribeiro-Dos-Santos R, Mello LE, Longo BM. Anticonvulsant activity of bone marrow cells in electroconvulsive seizures in mice. BMC Neurosci 2013; 14:97. [PMID: 24011127 PMCID: PMC3846761 DOI: 10.1186/1471-2202-14-97] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2012] [Accepted: 09/03/2013] [Indexed: 11/16/2022] Open
Abstract
Background Bone marrow is an accessible source of progenitor cells, which have been investigated as treatment for neurological diseases in a number of clinical trials. Here we evaluated the potential benefit of bone marrow cells in protecting against convulsive seizures induced by maximum electroconvulsive shock (MES), a widely used model for screening of anti-epileptic drugs. Behavioral and inflammatory responses were measured after MES induction in order to verify the effects promoted by transplantation of bone marrow cells. To assess the anticonvulsant effects of bone marrow cell transplantation, we measured the frequency and duration of tonic seizure, the mortality rate, the microglial expression and the blood levels of cytokine IL-1, IL-6, IL-10 and TNF-α after MES induction. We hypothesized that these behavioral and inflammatory responses to a strong stimulus such as a convulsive seizure could be modified by the transplantation of bone marrow cells. Results Bone marrow transplanted cells altered the convulsive threshold and showed anticonvulsant effect by protecting from tonic seizures. Bone marrow cells modified the microglial expression in the analyzed brain areas, increased the IL-10 and attenuate IL-6 levels. Conclusions Bone marrow cells exert protective effects by blocking the course of electroconvulsive seizures. Additionally, electroconvulsive seizures induced acute inflammatory responses by altering the pattern of microglia expression, as well as in IL-6 and IL-10 levels. Our findings also indicated that the anticonvulsant effects of these cells can be tested with the MES model following the same paradigm used for drug testing in pharmacological screening. Studies on the inflammatory reaction in response to acute seizures in the presence of transplanted bone marrow cells might open a wide range of discussions on the mechanisms relevant to the pathophysiology of epilepsies.
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Affiliation(s)
- Enéas Galdini Ferrazoli
- Laboratório de Neurofisiologia, Departamento de Fisiologia, Federal University of São Paulo - UNIFESP, R, Botucatu, 862 5 andar, V, Clementino - CEP, 04023-066, São Paulo, Brazil.
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60
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Williamson LL, Bilbo SD. Chemokines and the hippocampus: a new perspective on hippocampal plasticity and vulnerability. Brain Behav Immun 2013; 30:186-94. [PMID: 23376170 DOI: 10.1016/j.bbi.2013.01.077] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2012] [Revised: 01/07/2013] [Accepted: 01/15/2013] [Indexed: 12/13/2022] Open
Abstract
The hippocampus is critical for several aspects of learning and memory and is unique among other cortical regions in structure, function and the potential for plasticity. This remarkable region recapitulates development throughout the lifespan with enduring neurogenesis and well-characterized plasticity. The structure and traits of the hippocampus that distinguish it from other brain regions, however, may be the same reasons that this important brain region is particularly vulnerable to insult and injury. The immune system within the brain responds to insult and injury, and the hippocampus and the immune system are extensively interconnected. Immune signaling molecules, cytokines and chemokines (chemotactic cytokines), are well known for their functions during insult or injury. They are also increasingly implicated in normal hippocampal neurogenesis (e.g., CXCR4 on newborn neurons), cellular plasticity (e.g., interleukin-6 in LTP maintenance), and learning and memory (e.g., interleukin-1β in fear conditioning). We provide evidence from the small but growing literature that neuroimmune interactions and immune signaling molecules, especially chemokines, may be a primary underlying mechanism for the coexistence of plasticity and vulnerability within the hippocampus. We also highlight the evidence that the hippocampus exhibits a remarkable resilience in response to diverse environmental events (e.g., enrichment, exercise), which all may converge onto common neuroimmune mechanisms.
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Affiliation(s)
- Lauren L Williamson
- Duke University, Genome Science Research Building 2, 210 Research Dr., Box 91050, Durham, NC 27710, United States.
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61
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Cell death and survival mechanisms are concomitantly active in the hippocampus of patients with mesial temporal sclerosis. Neuroscience 2013; 237:56-65. [DOI: 10.1016/j.neuroscience.2013.01.050] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2012] [Revised: 01/18/2013] [Accepted: 01/19/2013] [Indexed: 11/24/2022]
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62
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Sakharnova TA, Vedunova MV, Mukhina IV. Brain-derived neurotrophic factor (BDNF) and its role in the functioning of the central nervous system. NEUROCHEM J+ 2012. [DOI: 10.1134/s1819712412030129] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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63
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Jayaram B, Khan RS, Kastin AJ, Hsuchou H, Wu X, Pan W. Protective role of astrocytic leptin signaling against excitotoxicity. J Mol Neurosci 2012. [PMID: 23180096 DOI: 10.1007/s12031-012-9924-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Both proconvulsive and anticonvulsive roles of leptin have been reported, suggesting cell-specific actions of leptin in different models of seizure and epilepsy. The goal of our study was to determine the regulation and function of astrocytic leptin receptors in a mouse model of epilepsy and glutamate-induced cytotoxicity. We show that in pilocarpine-challenged mice developing epilepsy with recurrent seizures after a latent period of 2 weeks, hippocampal leptin receptor (ObR) immunofluorescence was increased at 6 weeks. This was more pronounced in astrocytes than in neurons. In cultured astrocytes, glutamate increased ObRa and ObRb expression, whereas leptin pretreatment attenuated glial cytotoxicity by excess glutamate, reflected by better preserved adenosine triphosphate production. The protective role of astrocytic leptin signaling is further supported by the higher lethality of the astrocyte-specific leptin receptor knockout mice in the initial phase of seizure production. Thus, leptin signaling in astrocytes plays a protective role against seizure, and the effects are at least partially mediated by attenuation of glutamate toxicity. Astrocytic leptin signaling, therefore, may be a novel therapeutic target.
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Affiliation(s)
- Bhavaani Jayaram
- Blood-Brain Barrier Group, Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA
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64
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Resection of the epileptogenic lesion abolishes seizures and reduces inflammatory cytokines of patients with temporal lobe epilepsy. J Neuroimmunol 2012; 254:125-30. [PMID: 23116880 DOI: 10.1016/j.jneuroim.2012.08.004] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 03/28/2012] [Accepted: 08/09/2012] [Indexed: 12/31/2022]
Abstract
Persistent neuroinflammation is implicated in the pathogenesis of seizures and neuronal degeneration of temporal lobe epilepsy (TLE). Circulating level of inflammatory cytokines was determined during inter-ictal period of 25 non-operated and 10 patients (OP) submitted to anterior temporal lobectomy. OP patients showed marked reduction of IL-1β, TNFα, MIP-1α, but not IL-6 and TGF-β1. Paired analysis done before and after lobectomy showed reduction of inflammatory cytokines but increased TGF-β1 levels, and lack of seizures for more than 6 months. Maintenance of high TGF-β1 and IL-6 cytokines in both groups suggests a role in down-regulation of neuroinflammation and promotion of brain tissue remodeling for neuronal reorganization.
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65
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Yi MH, Zhang E, Kang JW, Shin YN, Byun JY, Oh SH, Seo JH, Lee YH, Kim DW. Expression of CD200 in alternative activation of microglia following an excitotoxic lesion in the mouse hippocampus. Brain Res 2012; 1481:90-6. [PMID: 22975132 DOI: 10.1016/j.brainres.2012.08.053] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Revised: 08/10/2012] [Accepted: 08/28/2012] [Indexed: 12/23/2022]
Abstract
CD200 is a glycoprotein that is expressed on the surfaces of neurons and other cells. It interacts with its receptor, CD200R, which is expressed on cells of the myeloid lineage, including microglia. The interaction of CD200 with its receptor plays a significant role in maintaining microglia in a quiescent state; thus, a decrease in CD200 expression in the brain is associated with evidence of microglial activation. However, their roles in pathological progression remain unclear. We examined the expression of CD200 in kainic acid (KA)-induced neurodegeneration of the mouse hippocampus. Our quantitative analysis revealed that CD200 was constitutively expressed in the normal brain and transiently upregulated by KA treatment. At the cellular level, CD200 was expressed in neurons in control, and was upregulated primarily in the microglia of KA-treated mouse hippocampi. We examined the contribution of CD200 to both the classical and alternative activation of microglia in vitro using an adult microglia culture, which was exposed to interleukin-4 (IL-4) with and without lipopolysaccharide (LPS). CD200 expression was increased after exposure to IL-4, but not to LPS. These in vivo experiments demonstrated that CD200 was transiently expressed in microglia in a process mediated by the inflammatory response. Based on CD200R expression in microglia, it suggests that microglia is maintained in an activated state with autocrine signaling by interactions between microglial CD200 and its CD200R. Moreover, we suggest that CD200 may be expressed in the alternative activation of microglia and play a beneficial role in neuroinflammation.
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Affiliation(s)
- Min-Hee Yi
- Department of Anatomy, Brain Research Institute, Chungnam National University School of Medicine, Daejeon, South Korea
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66
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Abstract
Although long granted the status of immune privilege, the central nervous system is not completely isolated from the immune system. Increasing evidence suggests that this system contributes to seizures and epilepsy and that the molecular mediators of inflammation and immunity may serve as appropriate targets in the quest to develop novel antiepileptic drugs that are more efficacious and potentially disease modifying.
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67
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Lou G, Zhang Q, Xiao F, Xiang Q, Su Z, Zhang L, Yang P, Yang Y, Zheng Q, Huang Y. Intranasal administration of TAT-haFGF(₁₄₋₁₅₄) attenuates disease progression in a mouse model of Alzheimer's disease. Neuroscience 2012; 223:225-37. [PMID: 22885230 DOI: 10.1016/j.neuroscience.2012.08.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/26/2012] [Accepted: 08/02/2012] [Indexed: 01/01/2023]
Abstract
Human acidic fibroblast growth factor (haFGF), a neurotrophin-like growth factor in the brain, plays important roles in the development, differentiation and regeneration of brain neurons, which makes it potential to treat Alzheimer's disease (AD). In this study, haFGF(14-154) and TAT-haFGF(14-154) (haFGF(14-154) fused with the cell-penetrating peptide transactivator of transcription protein transduction domain (TAT-PTD)) were intranasally administrated for 5 weeks to investigate the effects on senescence-accelerated mouse prone-8 (SAMP8) mice (a mouse model of AD). Results showed that TAT-PTD could increase the concentration of haFGF in the brain significantly, and TAT-haFGF(14-154) was more effective than haFGF(14-154) in the same dosage (300 μg/kg). Importantly, TAT-haFGF(14-154) improved the learning and memory abilities of SAMP8 mice in the behavioral test, and promoted the function of cholinergic system by measuring the relevant biomarkers (acetylcholine (ACh) level, acetylcholinesterase (AChE) and choline acetyltransferase (ChAT) activities). TAT-haFGF(14-154) also significantly reduced β-amyloid protein(1-42) (Aβ(1-42)) deposits as well as the levels of Aβ soluble forms in the mice brains and prevented the neurons from apoptosis. Besides, the oxidative stress impairment in the brain and serum was also ameliorated. The results suggest that TAT-haFGF(14-154) could attenuate the disease progression of SAMP8 AD mice, and the mechanism is related to the regulation of neurons microenvironment including neurotransmitters, Aβ pathology and oxidative stress.
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Affiliation(s)
- G Lou
- Institute of Biomedicine, Jinan University, Guangzhou 510632, China
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68
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Kramer K, Schaudien D, Eisel ULM, Herzog S, Richt JA, Baumgärtner W, Herden C. TNF-overexpression in Borna disease virus-infected mouse brains triggers inflammatory reaction and epileptic seizures. PLoS One 2012; 7:e41476. [PMID: 22848506 PMCID: PMC3405098 DOI: 10.1371/journal.pone.0041476] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2012] [Accepted: 06/26/2012] [Indexed: 11/19/2022] Open
Abstract
Proinflammatory state of the brain increases the risk for seizure development. Neonatal Borna disease virus (BDV)-infection of mice with neuronal overexpression of tumor necrosis factor-α (TNF) was used to investigate the complex relationship between enhanced cytokine levels, neurotropic virus infection and reaction pattern of brain cells focusing on its role for seizure induction. Viral antigen and glial markers were visualized by immunohistochemistry. Different levels of TNF in the CNS were provided by the use of heterozygous and homozygous TNF overexpressing mice. Transgenic TNF, total TNF (native and transgenic), TNF-receptor (TNFR1, TNFR2), IL-1 and N-methyl-D-aspartate (NMDA)-receptor subunit 2B (NR2B) mRNA values were measured by real time RT-PCR. BDV-infection of TNF-transgenic mice resulted in non-purulent meningoencephalitis accompanied by epileptic seizures with a higher frequency in homozygous animals. This correlated with lower weight gain, stronger degree and progression of encephalitis and early, strong microglia activation in the TNF-transgenic mice, most obviously in homozygous animals. Activation of astroglia could be more intense and associated with an unusual hypertrophy in the transgenic mice. BDV-antigen distribution and infectivity in the CNS was comparable in TNF-transgenic and wild-type animals. Transgenic TNF mRNA-expression was restricted to forebrain regions as the transgene construct comprised the promoter of NMDA-receptor subunit2B and induced up-regulation of native TNF mRNA. Total TNF mRNA levels did not increase significantly after BDV-infection in the brain of transgenic mice but TNFR1, TNFR2 and IL-1 mRNA values, mainly in the TNF overexpressing brain areas. NR2B mRNA levels were not influenced by transgene expression or BDV-infection. Neuronal TNF-overexpression combined with BDV-infection leads to cytokine up-regulation, CNS inflammation and glial cell activation and confirmed the presensitizing effect of elevated cytokine levels for the development of spontaneous epileptic seizures when exposed to additional infectious noxi.
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MESH Headings
- Animals
- Borna Disease/genetics
- Borna Disease/metabolism
- Borna Disease/pathology
- Borna disease virus/genetics
- Borna disease virus/metabolism
- Epilepsy/genetics
- Epilepsy/metabolism
- Epilepsy/pathology
- Epilepsy/virology
- Interleukin-18 Receptor alpha Subunit/biosynthesis
- Interleukin-18 Receptor alpha Subunit/genetics
- Mice
- Mice, Transgenic
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Neuroglia/metabolism
- Neuroglia/pathology
- Neuroglia/virology
- Prosencephalon/metabolism
- Prosencephalon/pathology
- Prosencephalon/virology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptors, N-Methyl-D-Aspartate/biosynthesis
- Receptors, N-Methyl-D-Aspartate/genetics
- Receptors, Tumor Necrosis Factor, Type I/biosynthesis
- Receptors, Tumor Necrosis Factor, Type I/genetics
- Receptors, Tumor Necrosis Factor, Type II/biosynthesis
- Receptors, Tumor Necrosis Factor, Type II/genetics
- Tumor Necrosis Factor-alpha/biosynthesis
- Tumor Necrosis Factor-alpha/genetics
- Up-Regulation/genetics
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Affiliation(s)
- Katharina Kramer
- Department of Pathology, University of Veterinary Medicine, Hannover, Germany
| | - Dirk Schaudien
- Department of Pathology, University of Veterinary Medicine, Hannover, Germany
| | - Ulrich L. M. Eisel
- Department of Molecular Neurobiology, University of Groningen, Groningen, The Netherlands
| | - Sibylle Herzog
- Institute of Virology, Justus-Liebig-University, Gießen, Germany
| | - Jürgen A. Richt
- Department of Diagnostic Medicine/Pathobiology, Kansas State University, Manhattan, Kansas, United States of America
| | | | - Christiane Herden
- Department of Pathology, University of Veterinary Medicine, Hannover, Germany
- * E-mail:
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69
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Boulle F, Kenis G, Cazorla M, Hamon M, Steinbusch HWM, Lanfumey L, van den Hove DLA. TrkB inhibition as a therapeutic target for CNS-related disorders. Prog Neurobiol 2012; 98:197-206. [PMID: 22705453 DOI: 10.1016/j.pneurobio.2012.06.002] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 05/30/2012] [Accepted: 06/06/2012] [Indexed: 01/04/2023]
Abstract
The interaction of brain-derived neurotrophic factor (BDNF) with its tropomyosin-related kinase receptor B (TrkB) is involved in fundamental cellular processes including neuronal proliferation, differentiation and survival as well as neurotransmitter release and synaptic plasticity. TrkB signaling has been widely associated with beneficial, trophic effects and many commonly used psychotropic drugs aim to increase BDNF levels in the brain. However, it is likely that a prolonged increased TrkB activation is observed in many pathological conditions, which may underlie the development and course of clinical symptoms. Interestingly, genetic and pharmacological studies aiming at decreasing TrkB activation in rodent models mimicking human pathology have demonstrated a promising therapeutic landscape for TrkB inhibitors in the treatment of various diseases, e.g. central nervous system (CNS) disorders and several types of cancer. Up to date, only a few selective and potent TrkB inhibitors have been developed. As such, the use of crystallography and in silico approaches to model BDNF-TrkB interaction and to generate relevant pharmacophores represent powerful tools to develop novel compounds targeting the TrkB receptor.
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Affiliation(s)
- Fabien Boulle
- Department of Psychiatry and Neuropsychology, Maastricht University, European Graduate School for Neuroscience (EURON), Maastricht, The Netherlands
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70
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Das A, Wallace GC, Holmes C, McDowell ML, Smith JA, Marshall JD, Bonilha L, Edwards JC, Glazier SS, Ray SK, Banik NL. Hippocampal tissue of patients with refractory temporal lobe epilepsy is associated with astrocyte activation, inflammation, and altered expression of channels and receptors. Neuroscience 2012; 220:237-46. [PMID: 22698689 DOI: 10.1016/j.neuroscience.2012.06.002] [Citation(s) in RCA: 150] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2012] [Revised: 05/17/2012] [Accepted: 06/03/2012] [Indexed: 11/24/2022]
Abstract
Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy. Previous research has demonstrated several trends in human tissue that, undoubtedly, contribute to the development and progression of TLE. In this study we examined resected human hippocampus tissue for a variety of changes including gliosis that might contribute to the development and presentation of TLE. The study subjects consisted of six TLE patients and three sudden-death controls. Clinicopathological characteristics were evaluated by H&E staining. Immunohistological staining and Western blotting methods were used to analyze the samples. Neuronal hypertrophy was observed in resected epileptic tissue. Immunohistological staining demonstrated that activation of astrocytes was significantly increased in epileptic tissue as compared to corresponding regions of the control group. The Western blot data also showed increased CX43 and AQP4 in the hippocampus and downregulation of Kir4.1, α-syntrophin, and dystrophin, the key constituents of AQP4 multi-molecular complex. These tissues also demonstrated changes in inflammatory factors (COX-2, TGF-β, NF-κB) suggesting that these molecules may play an important role in TLE pathogenesis. In addition we detected increases in metabotropic glutamate receptor (mGluR) 2/3, mGluR5 and kainic acid receptor subunits KA1 (Grik4) and KA2 (Grik5) in patients' hippocampi. We noted increased expression of the α1c subunit comprising class C L-type Ca(2+) channels and calpain expression in these tissues, suggesting that these subunits might have an integral role in TLE pathogenesis. These changes found in the resected tissue suggest that they may contribute to TLE and that the kainic acid receptor (KAR) and deregulation of GluR2 receptor may play an important role in TLE development and disease course. This study identifies alterations in number of commonly studied molecular targets associated with astrogliosis, cellular hypertrophy, water homeostasis, inflammation, and modulation of excitatory neurotransmission in hippocampal tissues from TLE patients.
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Affiliation(s)
- A Das
- Department of Neurosciences (Divisions of Neurology and Neurosurgery), Medical University of South Carolina, Charleston, SC 29425, USA
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71
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Armagan G, Bojnik E, Turunc E, Kanit L, Gündüz Çinar O, Benyhe S, Borsodi A, Yalcin A. Kainic acid-induced changes in the opioid/nociceptin system and the stress/toxicity pathways in the rat hippocampus. Neurochem Int 2012; 60:555-64. [PMID: 22382076 DOI: 10.1016/j.neuint.2012.02.015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2011] [Revised: 02/10/2012] [Accepted: 02/11/2012] [Indexed: 12/13/2022]
Abstract
Excitotoxicity is a contributing factor to the pathogenesis of acute or chronic neurodegenerative disease states. Kainic acid (KA) is an excitotoxic substance and the administration of it to rodents induces seizure activity (status epilepticus, SE) and leads to neurodegeneration. In this study the effect of KA-induced excitotoxicity on the G-protein activations and the gene expression levels of the opioid/nociceptin system receptors as MOPr, KOPr, DOPr, ORL-1, and PNOC (N/OFQ) were investigated, and the regulator effect of naloxone (Nal) on the gene expressions of the opioid system receptors against KA-induced seizures in the rat hippocampus was tested. In addition, the expression levels of stress-toxicity genes were assessed in the hippocampus following KA-induced excitotoxicity in order to determine the potential genetic targets which can be helpful for neuroprotective interventions. Our results indicate that the KA-induced excitotoxicity increased the mRNA levels of MOPr, DOPr, KOPr, PNOC, and ORL-1. However, G-protein activations of MOPr, DOPr, and KOPr remained relatively unchanged while both the potency and efficacy of N/OFQ were significantly increased. The PCR array data showed that KA-induced excitotoxicity altered the expression levels of genes in the cellular stress or toxicity pathways. Our data suggests that the induction of the opioid/nociceptin system may be involved in the cellular stress response following a neurodegenerative insult and that the genes modulated by the KA-treatment in the stress-toxicity pathways may be evaluated as targets of potential neuroprotective interventions.
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Affiliation(s)
- Guliz Armagan
- Department of Biochemistry, Faculty of Pharmacy, Ege University, 35100 Bornova, Izmir, Turkey
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72
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Xu Y, Zeng K, Han Y, Wang L, Chen D, Xi Z, Wang H, Wang X, Chen G. Altered expression of CX3CL1 in patients with epilepsy and in a rat model. THE AMERICAN JOURNAL OF PATHOLOGY 2012; 180:1950-62. [PMID: 22464888 DOI: 10.1016/j.ajpath.2012.01.024] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 01/06/2012] [Accepted: 01/19/2012] [Indexed: 11/26/2022]
Abstract
Chemokine C-X3-C motif ligand 1 (CX3CL1, alias fractalkine), is highly expressed in the central nervous system and participates in inflammatory responses. Recent studies indicated that inflammatory processes within the brain constitute a common and crucial mechanism in the pathophysiological characteristics of epilepsy. This study investigated the expression pattern of CX3CL1 in epilepsy and its relationship with neuronal loss. Double immunolabeling, IHC, and immunoblotting results showed that CX3CL1 expression was up-regulated in the temporal neocortex of patients with temporal lobe epilepsy. In a rat model of epilepsy, CX3CL1 up-regulation began 6 hours after epilepsy, with relatively high expression for 60 days. In addition, ELISA revealed that the concentrations of CX3CL1 in cerebrospinal fluid and serum were higher in epileptic patients than in patients with neurosis but lower than in patients with inflammatory neurological diseases. Moreover, H&E staining demonstrated significant neuronal loss in the brains of epileptic patients and in the rat model. Finally, the expression of tumor necrosis factor-related apoptosis-inducing ligand was significantly increased in both patients and the animal model, suggesting that tumor necrosis factor-related apoptosis-inducing ligand may play a role in CX3CL1-induced cell death. Thus, our results indicate that CX3CL1 may serve as a possible biomarker of brain inflammation in epileptic patients.
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Affiliation(s)
- Yali Xu
- Department of Neurology, The First Affiliated Hospital, Chongqing Medical University, Chongqing Key Laboratory of Neurology, Chongqing, China
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73
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van Luijtelaar G, Lyashenko S, Vastyanov R, Verbeek G, Oleinik A, van Rijn C, Volokhova G, Shandra A, Coenen A, Godlevsky L. Cytokines and Absence Seizures in a Genetic Rat Model. NEUROPHYSIOLOGY+ 2012. [DOI: 10.1007/s11062-012-9252-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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74
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O'Dell CM, Das A, Wallace G, Ray SK, Banik NL. Understanding the basic mechanisms underlying seizures in mesial temporal lobe epilepsy and possible therapeutic targets: a review. J Neurosci Res 2012; 90:913-24. [PMID: 22315182 DOI: 10.1002/jnr.22829] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2011] [Revised: 10/05/2011] [Accepted: 10/09/2011] [Indexed: 12/13/2022]
Abstract
Despite years of research, epilepsy remains a poorly understood disorder. In the past several years, work has been conducted on a variety of projects with the goal of better understanding the pathogenesis and progression of mesial temporal lobe epilepsy (MTLE), in particular, and how to exploit those properties to generate innovative therapies for treatment of refractory epilepsies. This review seeks to give an overview of common morphological and biochemical changes associated with epilepsy and proposed treatments to address those changes. Furthering the understanding of ictogenesis and epileptogenesis remains an important goal for scientists seeking to find more effective treatments for MTLE.
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Affiliation(s)
- Casey M O'Dell
- Division of Neurology, Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, USA
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75
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Abstract
BACKGROUND Experimental and clinical studies support a pathogenic role of microglial activation and proliferation (MAP) in epileptogenesis. METHODS From a consecutive series of 319 surgically treated epilepsy cases, we retrospectively reviewed the histopathological sections of 92 cases to define the prevalence and severity of MAP after excluding the other 227 because of coexisting disorders that might contribute to MAP. Severity of MAP was compared with underlying abnormalities. We assessed the response to intravenous immunoglobulin and plasmapheresis in one patient with severe MAP who had failed multiple antiepileptic drugs and epilepsy surgery. RESULTS MAP was detected with routine (hematoxylin and eosin) stain in 46 of 92 cases (50%). MAP was mild in 32 cases (69.6%), moderate in 12 (26.1%), and severe in 2 (4.3%). The prevalence and severity of MAP were independent of underlying abnormalities. Immunomodulatory therapy was followed by a greater than 90% reduction in seizure activity in the treated patient. CONCLUSION MAP is prevalent in resected human epilepsy tissue. Failure to down-regulate MAP contributes to chronic neuronal hyperexcitability. We hypothesize that MAP initiates a cycle of inflammation-induced seizures and seizure-induced inflammation. Microglia-driven epilepsy may be a primary pathogenic process in a small number of cases, as suggested by the pathology and therapeutic response in our patient, but may contribute to epileptogenesis in many more.
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76
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Ablation of cyclooxygenase-2 in forebrain neurons is neuroprotective and dampens brain inflammation after status epilepticus. J Neurosci 2011; 31:14850-60. [PMID: 22016518 DOI: 10.1523/jneurosci.3922-11.2011] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cyclooxygenase-2 (COX-2), a source of inflammatory mediators and a multifunctional neuronal modulator, is rapidly induced in select populations of cortical neurons after status epilepticus. The consequences of rapid activity-triggered induction of COX-2 in neurons have been the subject of much study and speculation. To address this issue directly, we created a mouse in which COX-2 is conditionally ablated in selected forebrain neurons. Results following pilocarpine-induced status epilepticus indicate that neuronal COX-2 promotes early neuroprotection and then delayed neurodegeneration of CA1 pyramidal neurons, promotes neurodegeneration of nearby somatostatin interneurons in the CA1 stratum oriens and dentate hilus (which themselves do not express COX-2), intensifies a broad inflammatory reaction involving numerous cytokines and other inflammatory mediators in the hippocampus, and is essential for development of a leaky blood-brain barrier after seizures. These findings point to a profound role of seizure-induced neuronal COX-2 expression in neuropathologies that accompany epileptogenesis.
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77
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Xie C, Sun J, Qiao W, Lu D, Wei L, Na M, Song Y, Hou X, Lin Z. Administration of simvastatin after kainic acid-induced status epilepticus restrains chronic temporal lobe epilepsy. PLoS One 2011; 6:e24966. [PMID: 21949812 PMCID: PMC3176286 DOI: 10.1371/journal.pone.0024966] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Accepted: 08/22/2011] [Indexed: 11/18/2022] Open
Abstract
In this study, we examined the effect of chronic administration of simvastatin immediately after status epilepticus (SE) on rat brain with temporal lobe epilepsy (TLE). First, we evaluated cytokines expression at 3 days post KA-lesion in hippocampus and found that simvastatin-treatment suppressed lesion-induced expression of interleukin (IL)-1β and tumor necrosis factor-α (TNF-α). Further, we quantified reactive astrocytosis using glial fibrillary acidic protein (GFAP) staining and neuron loss using Nissl staining in hippocampus at 4-6 months after KA-lesion. We found that simvastatin suppressed reactive astrocytosis demonstrated by a significant decrease in GFAP-positive cells, and attenuated loss of pyramidal neurons in CA3 and interneurons in dentate hilar (DH). We next assessed aberrant mossy fiber sprouting (MFS) that is known to contribute to recurrence of spontaneous seizure in epileptic brain. In contrast to the robust MFS observed in saline-treated animals, the extent of MFS was restrained by simvastatin in epileptic rats. Attenuated MFS was related to decreased neuronal loss in CA3 and DH, which is possibly a mechanism underlying decreased hippocampal susceptibility in animal treated with simvastatin. Electronic encephalography (EEG) was recorded during 4 to 6 months after KA-lesion. The frequency of abnormal spikes in rats with simvastatin-treatment decreased significantly compared to the saline group. In summary, simvastatin treatment suppressed cytokines expression and reactive astrocytosis and decreased the frequency of discharges of epileptic brain, which might be due to the inhibition of MFS in DH. Our study suggests that simvastatin administration might be a possible intervention and promising strategy for preventing SE exacerbating to chronic epilepsy.
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Affiliation(s)
- Chuncheng Xie
- Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Jiahang Sun
- Department of Neurosurgery, The Second Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Weidong Qiao
- Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Dunyue Lu
- Department of Psychiatry, State University of New York Downstate Medical Center, Brooklyn, New York, United States of America
| | - Lanlan Wei
- Department of Microbiology, Harbin Medical University, Harbin, Heilongjiang, China
| | - Meng Na
- Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Yuanyuan Song
- Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Xiaohua Hou
- Department of Neurology, The First Affiliated Hospital of Harbin Medical University, Harbin, China
| | - Zhiguo Lin
- Department of Neurosurgery, The First Affiliated Hospital of Harbin Medical University, Harbin, China
- * E-mail:
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78
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Brain infiltration of leukocytes contributes to the pathophysiology of temporal lobe epilepsy. J Neurosci 2011; 31:4037-50. [PMID: 21411646 DOI: 10.1523/jneurosci.6210-10.2011] [Citation(s) in RCA: 195] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Clinical and experimental evidence indicates that inflammatory processes contribute to the pathophysiology of epilepsy, but underlying mechanisms remain mostly unknown. Using immunohistochemistry for CD45 (common leukocyte antigen) and CD3 (T-lymphocytes), we show here microglial activation and infiltration of leukocytes in sclerotic tissue from patients with mesial temporal lobe epilepsy (TLE), as well as in a model of TLE (intrahippocampal kainic acid injection), characterized by spontaneous, nonconvulsive focal seizures. Using specific markers of lymphocytes, microglia, macrophages, and neutrophils in kainate-treated mice, we investigated with pharmacological and genetic approaches the contribution of innate and adaptive immunity to kainate-induced inflammation and neurodegeneration. Furthermore, we used EEG analysis in mutant mice lacking specific subsets of lymphocytes to explore the significance of inflammatory processes for epileptogenesis. Blood-brain barrier disruption and neurodegeneration in the kainate-lesioned hippocampus were accompanied by sustained ICAM-1 upregulation, microglial cell activation, and infiltration of CD3(+) T-cells. Moreover, macrophage infiltration was observed, selectively in the dentate gyrus where prominent granule cell dispersion was evident. Unexpectedly, depletion of peripheral macrophages by systemic clodronate liposome administration affected granule cell survival. Neurodegeneration was aggravated in kainate-lesioned mice lacking T- and B-cells (RAG1-knock-out), because of delayed invasion by Gr-1(+) neutrophils. Most strikingly, these mutant mice exhibited early onset of spontaneous recurrent seizures, suggesting a strong impact of immune-mediated responses on network excitability. Together, the concerted action of adaptive and innate immunity triggered locally by intrahippocampal kainate injection contributes seizure-suppressant and neuroprotective effects, shedding new light on neuroimmune interactions in temporal lobe epilepsy.
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80
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Lachos J, Zattoni M, Wieser HG, Fritschy JM, Langmann T, Schmitz G, Errede M, Virgintino D, Yonekawa Y, Frei K. Characterization of the gene expression profile of human hippocampus in mesial temporal lobe epilepsy with hippocampal sclerosis. EPILEPSY RESEARCH AND TREATMENT 2011; 2011:758407. [PMID: 22937234 PMCID: PMC3428621 DOI: 10.1155/2011/758407] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Revised: 12/10/2010] [Accepted: 01/01/2011] [Indexed: 12/22/2022]
Abstract
One of the main putative causes of therapy refractory epilepsy in mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis is the overexpression of multidrug transporters (MDTs) at the blood-brain barrier (BBB). It steps up the removal of antiepileptic drugs (AEDs) out of the brain cells across the BBB resulting in a low concentration of AEDs within the target cells. Some of the mechanisms of AED resistance are most likely to be genetically determined. To obtain more information about the underlying pathophysiology of intractability in epilepsy, we compared the global gene expression profile of human hippocampus and hippocampal-derived microvascular endothelial cells from MTLE with HS patients and controls. At the level of MDT, a significant up-regulation was found for ABCB1 (P-gp), ABCB2, ABCB3, and ABCB4, which was mainly related to endothelial cells. The data on the MDT were validated and extended by quantitative RT-PCR. Surprisingly, inflammatory factors such as interleukins (IL-1α, IL-1β, IL-6, and IL-18) and cytokines (TNF-α and TGF-β1) were found to be up-regulated in hippocampal parenchyma. The overexpression of P-gp, IL-1β, and IL-6 was also confirmed by immunohistochemistry (IHC). Our results suggest that complex expression changes of ABC-transporters may play a decisive role in pharmacoresistance in MTLE. Further studies on the new and unexpected overexpression of inflammatory cytokines may unlock hitherto undiscovered pathways of the underlying pathophysiology of human MTLE.
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Affiliation(s)
- Julio Lachos
- Department of Neurosurgery, University Hospital Zurich, 8091 Zurich, Switzerland
- Department of Neurology, University Hospital Zurich, 8091 Zurich, Switzerland
- Department of Psychiatry, University Hospital Zurich, Culmannstrasse 8, 8091 Zurich, Switzerland
| | - Michela Zattoni
- Department of Neurosurgery, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Heinz-Gregor Wieser
- Department of Psychiatry, University Hospital Zurich, Culmannstrasse 8, 8091 Zurich, Switzerland
| | - Jean-Marc Fritschy
- Institute of Pharmacology and Toxicology, University of Zurich, 8057 Zurich, Switzerland
| | - Thomas Langmann
- Institute for Clinical Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Gerd Schmitz
- Institute for Clinical Chemistry, University of Regensburg, 93040 Regensburg, Germany
| | - Mariella Errede
- Department of Human Anatomy and Histology, Medical School, Bari University, 70124 Bari, Italy
| | - Daniela Virgintino
- Department of Human Anatomy and Histology, Medical School, Bari University, 70124 Bari, Italy
| | - Yasuhiro Yonekawa
- Department of Neurosurgery, University Hospital Zurich, 8091 Zurich, Switzerland
| | - Karl Frei
- Department of Neurosurgery, University Hospital Zurich, 8091 Zurich, Switzerland
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81
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Varella PPV, Santiago JFC, Carrete Jr. H, Higa EMS, Yacubian EMT, Centeno RS, Caboclo LOSF, Castro Neto EFD, Canzian M, Amado D, Cavalheiro EA, Naffah- Mazzacoratti MDG. Relationship between fluid-attenuated inversion-recovery (FLAIR) signal intensity and inflammatory mediator's levels in the hippocampus of patients with temporal lobe epilepsy and mesial temporal sclerosis. ARQUIVOS DE NEURO-PSIQUIATRIA 2011; 69:91-9. [DOI: 10.1590/s0004-282x2011000100018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Accepted: 08/02/2010] [Indexed: 11/22/2022]
Abstract
We investigated a relationship between the FLAIR signal found in mesial temporal sclerosis (MTS) and inflammation. Twenty nine patients were selected through clinical and MRI analysis and submitted to cortico-amygdalo-hippocampectomy to seizure control. Glutamate, TNFα, IL1, nitric oxide (NO) levels and immunostaining against IL1β and CD45 was performed. Control tissues (n=10) were obtained after autopsy of patients without neurological disorders. The glutamate was decreased in the temporal lobe epilepsy (TLE) -MTS group (p<0.001), suggesting increased release of this neurotransmitter. The IL1β and TNFα were increased in the hippocampus (p<0.05) demonstrating an active inflammatory process. A positive linear correlation between FLAIR signal and NO and IL1β levels and a negative linear correlation between FLAIR signal and glutamate concentration was found. Lymphocytes infiltrates were present in hippocampi of TLE patients. These data showed an association between hippocampal signal alteration and increased inflammatory markers in TLE-MTS.
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82
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You Y, Bai H, Wang C, Chen LW, Liu B, Zhang H, Gao GD. Myelin damage of hippocampus and cerebral cortex in rat pentylenetetrazol model. Brain Res 2011; 1381:208-16. [PMID: 21256118 DOI: 10.1016/j.brainres.2011.01.011] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 01/05/2011] [Accepted: 01/06/2011] [Indexed: 01/21/2023]
Abstract
Epilepsy is a chronic neurological disorder characterized by spontaneous recurrent seizures, which also occur in demyelinating diseases of the central nervous system (CNS) with a higher prevalence. Meanwhile, demyelination occurrings have been occasionally observed in CNS of epilepsy patients, indicating an association between demyelination and epileptic seizures by an unknown mechanism. However, no confirmative experimental evidence has yet been given. Thus, by using a rat pentylenetetrazol model, electroencephalogram (EEG), Western blotting, enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry, the present study provided direct evidence that myelin sheath damage in rat hippocampus and cerebral cortex started in the early stage of epileptic seizures induction and lasted with no further increase in severity in the development of epileptic seizures. It was illustrated that myelin sheath damage was not the result of oligodendrocyte destruction, but the autoantibodies against myelin basic protein (MBP) produced in peripheral circulation accompanied by increased permeability of blood-brain barrier (BBB) formed in the development of epileptic seizures. This study firstly provided experimental evidence for myelin sheath damage in PTZ-induced rat's epileptic seizures and further demonstrated that its possible cause was autoimmunoreaction.
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Affiliation(s)
- Yu You
- Department of Neurosurgery, Tangdu Hospital, The Fourth Military Medical University, Xi'an 710038, PR China
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Increase in BDNF-mediated TrkB signaling promotes epileptogenesis in a mouse model of mesial temporal lobe epilepsy. Neurobiol Dis 2011; 42:35-47. [PMID: 21220014 DOI: 10.1016/j.nbd.2011.01.001] [Citation(s) in RCA: 148] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2009] [Revised: 12/21/2010] [Accepted: 01/02/2011] [Indexed: 01/19/2023] Open
Abstract
Mesio-temporal lobe epilepsy (MTLE), the most common drug-resistant epilepsy syndrome, is characterized by the recurrence of spontaneous focal seizures after a latent period that follows, in most patients, an initial insult during early childhood. Many of the mechanisms that have been associated with the pathophysiology of MTLE are known to be regulated by brain-derived neurotrophic factor (BDNF) in the healthy brain and an excess of this neurotrophin could therefore play a critical role in MTLE development. However, such a function remains controversial as other studies revealed that BDNF could, on the contrary, exert protective effects regarding epilepsy development. In the present study, we further addressed the role of increased BDNF/TrkB signaling on the progressive development of hippocampal seizures in the mouse model of MTLE obtained by intrahippocampal injection of kainate. We show that hippocampal seizures progressively developed in the injected hippocampus during the first two weeks following kainate treatment, within the same time-frame as a long-lasting and significant increase of BDNF expression in dentate granule cells. To determine whether such a BDNF increase could influence hippocampal epileptogenesis via its TrkB receptors, we examined the consequences of (i) increased or (ii) decreased TrkB signaling on epileptogenesis, in transgenic mice overexpressing the (i) TrkB full-length or (ii) truncated TrkB-T1 receptors of BDNF. Epileptogenesis was significantly facilitated in mice with increased TrkB signaling but delayed in mutants with reduced TrkB signaling. In contrast, TrkB signaling did not influence granule cell dispersion, an important feature of this mouse model which is also observed in most MTLE patients. These results suggest that an increase in TrkB signaling, mediated by a long-lasting BDNF overexpression in the hippocampus, promotes epileptogenesis in MTLE.
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Gouveia TLF, Scorza FA, Silva MJV, Bandeira TDA, Perosa SR, Argañaraz GA, Silva MDP, Araujo TR, Frangiotti MIB, Amado D, Cavalheiro EA, Silva JA, Naffah-Mazzacoratti MDG. Lovastatin decreases the synthesis of inflammatory mediators in the hippocampus and blocks the hyperthermia of rats submitted to long-lasting status epilepticus. Epilepsy Behav 2011; 20:1-5. [PMID: 21130693 DOI: 10.1016/j.yebeh.2010.10.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/21/2010] [Accepted: 10/03/2010] [Indexed: 01/13/2023]
Abstract
Statins may act on inflammatory responses, decreasing oxidative stress and also reducing temperature after a brain ischemic insult. Previous data have indicated that statins protect neurons from death during long-lasting status epilepticus (SE) and attenuate seizure behaviors in animals treated with kainic acid. In this context, the study described here aimed to investigate the effect of lovastatin on body temperature and on mRNA expression levels of hippocampal cytokines such as interleukin-1β, interleukin-6, tumor necrosis factor α, and kinin B1 and B2 receptors of rats submitted to pilocarpine-induced SE. Quantitative real-time polymerase chain reaction showed a significant decrease in mRNA expression of interleukin-1β, interleukin-6, tumor necrosis factor α, and kinin B1 receptor in animals with SE treated with lovastatin, compared with untreated animals with SE (P<0.001). Lovastatin also reduced SE-induced hyperthermia, indicating that mechanisms related to brain protection are triggered by this drug under conditions associated with acute excitotoxicity or long-lasting SE.
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Stienen MN, Haghikia A, Dambach H, Thöne J, Wiemann M, Gold R, Chan A, Dermietzel R, Faustmann PM, Hinkerohe D, Prochnow N. Anti-inflammatory effects of the anticonvulsant drug levetiracetam on electrophysiological properties of astroglia are mediated via TGFβ1 regulation. Br J Pharmacol 2011; 162:491-507. [PMID: 20955362 PMCID: PMC3031068 DOI: 10.1111/j.1476-5381.2010.01038.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2010] [Revised: 08/29/2010] [Accepted: 09/02/2010] [Indexed: 01/29/2023] Open
Abstract
BACKGROUND AND PURPOSE The involvement of astrocytes as immune-competent players in inflammation and the pathogenesis of epilepsy and seizure-induced brain damage has recently been recognized. In clinical trials and practice, levetiracetam (LEV) has proven to be an effective antiepileptic drug (AED) in various forms of epileptic seizures, when applied as mono- or added therapy. Little is known about the mechanism(s) of action of LEV. Evidence so far suggests a mode of action different from that of classical AEDs. We have shown that LEV restored functional gap junction coupling and basic membrane properties in an astrocytic inflammatory model in vitro. EXPERIMENTAL APPROACH Here, we used neonatal rat astrocytes co-cultured with high proportions (30%) of activated microglia or treated with the pro-inflammatory cytokine interleukin-1β to provoke inflammatory responses. Effects of LEV (50 µg·mL⁻¹) on electrophysiological properties of astrocytes (by whole cell patch clamp) and on secretion of TGFβ1 (by (ELISA)) were studied in these co-cultures. KEY RESULTS LEV restored impaired astrocyte membrane resting potentials via modification of inward and outward rectifier currents, and promoted TGFβ1 expression in inflammatory and control co-cultures. Furthermore, LEV and TGFβ1 exhibited similar facilitating effects on the generation of astrocyte voltage-gated currents in inflammatory co-cultures and the effects of LEV were prevented by antibody to TGFβ1. CONCLUSIONS AND IMPLICATIONS Our data suggest that LEV is likely to reduce the harmful spread of excitation elicited by seizure events within the astro-glial functional syncytium, with stabilizing consequences for neuronal-glial interactions.
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Andrzejczak D. Padaczka a cytokiny prozapalne. Immunomodulujące właściwości leków przeciwpadaczkowych. Neurol Neurochir Pol 2011; 45:275-85. [DOI: 10.1016/s0028-3843(14)60080-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Yang T, Zhou D, Stefan H. Why mesial temporal lobe epilepsy with hippocampal sclerosis is progressive: uncontrolled inflammation drives disease progression? J Neurol Sci 2010; 296:1-6. [PMID: 20663517 DOI: 10.1016/j.jns.2010.06.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2010] [Revised: 05/28/2010] [Accepted: 06/02/2010] [Indexed: 02/05/2023]
Abstract
Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is a group of chronic disorders characterized by prominent neuronal loss and gliosis in the hippocampus and amygdala. Newly published data indicate that it may be a progressive disease, but the mechanism underlying the progressive nature remains unknown. Recently, substantial evidence for an inflammatory mechanism in MTLE has been documented. We are therefore presenting a review of literature concerning the effects of uncontrolled inflammation on the disease progression of MTLE-HS. We found that increasing amounts of evidence support the association between uncontrolled inflammation and progression of the disease. Uncontrolled inflammatory processes may be a main mechanism underlying the self-propagating cycle of uncontrolled inflammation, blood-brain barrier damage, and seizures that drive the progressive nature. Thus it is important to unravel the principles of communication between the different factors in this cycle. The dynamic modulation of inflammatory processes aimed at preventing or interrupting this cycle has the potential to emerge as a novel therapeutic strategy. This line of therapy might offer new perspectives on the pharmacologic treatment of seizures, and possibly on delaying disease progression or retarding epileptogenesis as well.
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Affiliation(s)
- Tianhua Yang
- Department of Neurology, West China Hospital, Si Chuan University, Cheng du, Sichuan, China
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88
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Jin X, Huguenard JR, Prince DA. Reorganization of inhibitory synaptic circuits in rodent chronically injured epileptogenic neocortex. Cereb Cortex 2010; 21:1094-104. [PMID: 20855494 DOI: 10.1093/cercor/bhq181] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Reduced synaptic inhibition is an important factor contributing to posttraumatic epileptogenesis. Axonal sprouting and enhanced excitatory synaptic connectivity onto rodent layer V pyramidal (Pyr) neurons occur in epileptogenic partially isolated (undercut) neocortex. To determine if enhanced excitation also affects inhibitory circuits, we used laser scanning photostimulation of caged glutamate and whole-cell recordings from GAD67-GFP-expressing mouse fast spiking (FS) interneurons and Pyr cells in control and undercut in vitro slices to map excitatory and inhibitory synaptic inputs. Results are 1) the region-normalized excitatory postsynaptic current (EPSC) amplitudes and proportion of uncaging sites from which EPSCs could be evoked (hotspot ratio) "increased" significantly in FS cells of undercut slices; 2) in contrast, these parameters were significantly "decreased" for inhibitory postsynaptic currents (IPSCs) in undercut FS cells; and 3) in rat layer V Pyr neurons, we found significant decreases in IPSCs in undercut versus control Pyr neurons. The decreases were mainly located in layers II and IV, suggesting a reduction in the efficacy of interlaminar synaptic inhibition. Results suggest that there is significant synaptic reorganization in this model of posttraumatic epilepsy, resulting in increased excitatory drive and reduced inhibitory input to FS interneurons that should enhance their inhibitory output and, in part, offset similar alterations in innervation of Pyr cells.
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Affiliation(s)
- Xiaoming Jin
- Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, CA 94305, USA
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TrkB/BDNF-dependent striatal plasticity and behavior in a genetic model of epilepsy: modulation by valproic acid. Neuropsychopharmacology 2010; 35:1531-40. [PMID: 20200504 PMCID: PMC3055450 DOI: 10.1038/npp.2010.23] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In mice lacking the central domain of the presynaptic scaffold Bassoon the occurrence of repeated cortical seizures induces cell-type-specific plasticity changes resulting in a general enhancement of the feedforward inhibition within the striatal microcircuit. Early antiepileptic treatment with valproic acid (VPA) reduces epileptic attacks, inhibits the emergence of pathological form of plasticity in fast-spiking (FS) interneurons and restores physiological striatal synaptic plasticity in medium spiny (MS) neurons. Brain-derived neurotrophic factor (BDNF) is a key factor for the induction and maintenance of synaptic plasticity and it is also implicated in the mechanisms underlying epilepsy-induced adaptive changes. In this study, we explore the possibility that the TrkB/BDNF system is involved in the striatal modifications associated with the Bassoon gene (Bsn) mutation. In epileptic mice abnormal striatum-dependent learning was paralleled by higher TrkB levels and an altered distribution of BDNF. Accordingly, subchronic intrastriatal administration of k252a, an inhibitor of TrkB receptor tyrosine kinase activity, reversed behavioral alterations in Bsn mutant mice. In addition, in vitro manipulations of the TrkB/BDNF complex by k252a, prevented the emergence of pathological plasticity in FS interneurons. Chronic treatment with VPA, by reducing seizures, was able to rebalance TrkB to control levels favoring a physiological redistribution of BDNF between MS neurons and FS interneurons with a concomitant recovery of striatal plasticity. Our results provide the first indication that BDNF is involved in determining the striatal alterations occurring in the early-onset epileptic syndrome associated with the absence of presynaptic protein Bassoon.
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90
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Kim J, Gale K, Kondratyev A. Effects of repeated minimal electroshock seizures on NGF, BDNF and FGF-2 protein in the rat brain during postnatal development. Int J Dev Neurosci 2010; 28:227-32. [PMID: 20170723 DOI: 10.1016/j.ijdevneu.2010.02.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 01/28/2010] [Accepted: 02/09/2010] [Indexed: 11/19/2022] Open
Abstract
Repeated brief seizures, such as those induced by electroconvulsive therapy (ECT), markedly elevate neurotrophic factor levels in the adult rat brain, but it is not known whether a similar response to seizures occurs in immature animals. To address this question, we evoked brief seizures with electroconvulsive shock (ECS) in rat pups at different stages of postnatal development and examined basic fibroblast growth factor (FGF-2), nerve growth factor (NGF), and brain-derived neurotrophic factor (BDNF) proteins in selected brain regions in which these trophic factors are known to increase in the adult rat following ECS-induced seizures. ECS treatments were administered daily (3 episodes/day) over 7 days to rat pups of three different ages: postnatal day (P)1-7, P7-13, or P14-20. Protein levels were measured 6h after the last ECS using Western blotting for FGF-2 in rhinal cortex, ELISA for BDNF and NGF in hippocampus, and NGF in frontal cortex. 7 days of repeated ECS-induced seizures during P1-7 did not alter protein levels for BDNF, FGF-2, or NGF. The repeated seizures during P7-13 affected only BDNF protein, causing a significant elevation of 40% in hippocampus over sham-treated controls. In P14-20 pups, the repeated seizures resulted in a significant increase in BDNF in hippocampus (162% over controls) and FGF-2 in rhinal cortex (34% over controls), while NGF protein did not show a significant change in either hippocampus or frontal cortex. The results suggest that during the first postnatal week there is a resistance to seizure-induced increase in neurotrophic factors, but by the third postnatal week, both BDNF and FGF-2 are elevated substantially in response to repeated seizures. This time-dependent profile suggests that synthesis of these proteins is initially activity-independent, becoming subject to activity-dependent regulation by 3 weeks of age. This maturation of seizure-evoked changes in trophic factors may be important for understanding the impact of ECT and seizures in childhood.
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Affiliation(s)
- Jinsook Kim
- Interdisciplinary Program in Neuroscience, Georgetown University Medical Center, Washington, DC 20057, USA
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91
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Abstract
Febrile seizures (FSs) are seizures that occur during fever, usually at the time of a cold or flu, and represent the most common cause of seizures in the pediatric population. Up to 5% of children between the ages of six months and five years-of-age will experience a FS. Clinically these seizures are categorized as benign events with little impact on the growth and development of the child. However, studies have linked the occurrence of FSs to an increased risk of developing adult epileptic disorders. There are many unanswered questions about FSs, such as the mechanism of their generation, the long-term effects of these seizures, and their role in epileptogenesis. Answers are beginning to emerge based on results from animal studies. This review summarizes the current literature on animal models of FSs, mechanisms underlying the seizures, and functional, structural, and molecular changes that may result from them.
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92
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Choi J, Nordli DR, Alden TD, DiPatri A, Laux L, Kelley K, Rosenow J, Schuele SU, Rajaram V, Koh S. Cellular injury and neuroinflammation in children with chronic intractable epilepsy. J Neuroinflammation 2009; 6:38. [PMID: 20021679 PMCID: PMC2811703 DOI: 10.1186/1742-2094-6-38] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2009] [Accepted: 12/19/2009] [Indexed: 11/25/2022] Open
Abstract
Objective To elucidate the presence and potential involvement of brain inflammation and cell death in neurological morbidity and intractable seizures in childhood epilepsy, we quantified cell death, astrocyte proliferation, microglial activation and cytokine release in brain tissue from patients who underwent epilepsy surgery. Methods Cortical tissue was collected from thirteen patients with intractable epilepsy due to focal cortical dysplasia (6), encephalomalacia (5), Rasmussen's encephalitis (1) or mesial temporal lobe epilepsy (1). Sections were processed for immunohistochemistry using markers for neuron, astrocyte, microglia or cellular injury. Cytokine assay was performed on frozen cortices. Controls were autopsy brains from eight patients without history of neurological diseases. Results Marked activation of microglia and astrocytes and diffuse cell death were observed in epileptogenic tissue. Numerous fibrillary astrocytes and their processes covered the entire cortex and converged on to blood vessels, neurons and microglia. An overwhelming number of neurons and astrocytes showed DNA fragmentation and its magnitude significantly correlated with seizure frequency. Majority of our patients with abundant cell death in the cortex have mental retardation. IL-1beta, IL-8, IL-12p70 and MIP-1beta were significantly increased in the epileptogenic cortex; IL-6 and MCP-1 were significantly higher in patients with family history of epilepsy. Conclusions Our results suggest that active neuroinflammation and marked cellular injury occur in pediatric epilepsy and may play a common pathogenic role or consequences in childhood epilepsy of diverse etiologies. Our findings support the concept that immunomodulation targeting activated microglia and astrocytes may be a novel therapeutic strategy to reduce neurological morbidity and prevent intractable epilepsy.
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Affiliation(s)
- Jieun Choi
- Department of Pediatrics, Northwestern University Children's Memorial Hospital, Chicago, IL, USA.
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93
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Contributions of peripheral inflammation to seizure susceptibility: cytokines and brain excitability. Epilepsy Res 2009; 89:34-42. [PMID: 19804959 DOI: 10.1016/j.eplepsyres.2009.09.004] [Citation(s) in RCA: 221] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2009] [Revised: 09/04/2009] [Accepted: 09/07/2009] [Indexed: 01/23/2023]
Abstract
Inflammation is an important factor in the pathophysiology of seizure generation and epileptogenesis. While the role of CNS inflammation is well acknowledged as an important factor in seizure pathophysiology, less is known about the role of peripheral inflammation. Systemic inflammation induces a mirror inflammatory response in the brain that might have transient or long-term effects on seizure susceptibility. The focus of our laboratory research is the study of the interaction of systemic inflammatory events with neuronal excitability and seizure susceptibility. In this paper we provide a review of our findings and discuss possible mechanisms.
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94
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Jaako K, Zharkovsky T, Zharkovsky A. Effects of repeated citalopram treatment on kainic acid-induced neurogenesis in adult mouse hippocampus. Brain Res 2009; 1288:18-28. [DOI: 10.1016/j.brainres.2009.06.089] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2009] [Revised: 06/23/2009] [Accepted: 06/26/2009] [Indexed: 02/01/2023]
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Increased levels of proinflammatory cytokines in the aged rat brain attenuate injury-induced cytokine response after excitotoxic damage. J Neurosci Res 2009; 87:2484-97. [PMID: 19326443 DOI: 10.1002/jnr.22074] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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96
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Godukhin OV, Levin SG, Parnyshkova EY. The effects of interleukin-10 on the development of epileptiform activity in the hippocampus induced by transient hypoxia, bicuculline, and electrical kindling. ACTA ACUST UNITED AC 2009; 39:625-31. [PMID: 19621265 DOI: 10.1007/s11055-009-9187-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2007] [Accepted: 11/12/2007] [Indexed: 11/29/2022]
Abstract
The comparative effects of the anti-inflammatory cytokine interleukin-10 on the development of epileptiform activity were studied in hippocampal field CA1 neurons in different models of epileptogenesis not accompanied by visible morphological lesions in brain cells: 1) a model of hypoxic kindling in rat hippocampal slices; 2) a disinhibitory model of epileptogenesis in rat hippocampal slices using the GABAA receptor blocker bicuculline; and 3) a partial electrical kindling model in intact rats. Interleukin-10 (1 ng/ml) blocked the development of post-hypoxic hyperexcitability of field CA1 pyramidal neurons in hippocampal slices, decreasing the effectiveness of hypoxia in suppressing neuron activity during the hypoxic episode. Interleukin-10 had no effect on the initiation of epileptiform activity in pyramidal neurons induced by the proconvulsant bicuculline. Single intrahippocampal injections of interleukin-10 at a dose of 1 ng in 5 microl suppressed the development of focal convulsions ("ictal" discharges) at the stimulation site in partial kindling in freely moving animals for several hours after administration. However, this cytokine had no effect on the duration of the "interictal" component of focal afterdischarges or on the severity of behavioral seizures. These results show that the anti-inflammatory cytokine interleukin-10, at the concentrations used here, has not only antihypoxic activity, but also a protective effect in relation to the initiation of the "ictal," but not the "interictal" component of epileptiform activity in hippocampal neurons.
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Affiliation(s)
- O V Godukhin
- Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, Pushchino, Russia.
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97
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Conti G, Gale K, Kondratyev A. Immunohistochemical evaluation of the protein expression of nerve growth factor and its TrkA receptor in rat limbic regions following electroshock seizures. Neurosci Res 2009; 65:201-9. [PMID: 19596387 DOI: 10.1016/j.neures.2009.07.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 06/26/2009] [Accepted: 07/01/2009] [Indexed: 01/01/2023]
Abstract
Repeated (but not acute) exposure to brief, non-injurious seizures evoked by minimal electroconvulsive shock (ECS) decreases neuronal death in limbic system and increases mRNA levels for nerve growth factor (NGF). Thus, the induction of NGF is a potential mechanism for the neuroprotection evoked by repeated ECS. The neuroprotective action of NGF is mediated by the TrkA receptor. This study determined whether repeated ECS exposure increased TrkA and NGF protein levels. To determine the functional significance of changes in these proteins, we compared the effects of ECS given daily either for 7 days (chronic ECS) or for 1 day (acute ECS). After chronic ECS, upregulation of both NGF and TrkA was found in perirhinal cortex, thalamus, and amygdala. In hippocampus, TrkA was upregulated in CA2, CA3 and CA4. NGF increase in hippocampus was found in CA1 and dentate gyrus. In frontal cortex and substantia innominata, an increase in NGF (but not in TrkA) was found. In most brain regions, TrkA and NGF remained unchanged after acute ECS. Our results demonstrate that repeated exposure to ECS causes an upregulation of TrkA and NGF proteins in several limbic areas in which neuroprotective effects are observed suggesting that NGF contributes to ECS-evoked neuroprotection.
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Affiliation(s)
- Giuseppe Conti
- Department of Pharmacology, Georgetown University, Washington, DC 20057, USA
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98
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Parinejad N, Keshavarzi S, Movahedin M, Raza M. Behavioral and histological assessment of the effect of intermittent feeding in the pilocarpine model of temporal lobe epilepsy. Epilepsy Res 2009; 86:54-65. [PMID: 19505798 DOI: 10.1016/j.eplepsyres.2009.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2008] [Revised: 04/26/2009] [Accepted: 05/01/2009] [Indexed: 01/17/2023]
Abstract
Temporal lobe epilepsy (TLE) is the most resistant type of epilepsy. Currently available drugs for epilepsy are not antiepileptogenic. A novel treatment for epilepsy would be to block or reverse the process of epileptogenesis. We used intermittent feeding (IF) regimen of the dietary restriction (DR) to study its effect on epileptogenesis and neuroprotection in the pilocarpine model of TLE in rats. The effect of IF regimen on the induction of status epilepticus (SE), the duration of latent period, and the frequency, duration, severity and the time of occurrence of Spontaneous Recurrent Seizures (SRS) were investigated. We also studied the effect of IF regimen on hippocampal neurons against the excitotoxic damage of prolonged SE (about 4h) induced by pilocarpine. The animals (Wistar, male, 200-250g) were divided into four main groups: AL-AL (ad libitum diet throughout), AL-IF (PfS) [IF post-first seizure], AL-IF (PSE) [IF post-SE] and IF-IF (IF diet throughout), and two AL and IF control groups. SE was induced by pilocarpine (350mg/kg, i.p.) and with diazepam (6mg/kg, i.p.) injected after 3h, the behavioral signs of SE terminated at about 4h (AL animals, n=29, 260.43+/-8.74min; IF animals, n=19, 224.32+/-20.73min). Behavioral monitoring was carried out by 24h video recording for 3 weeks after the first SRS. Rat brains were then prepared for histological study with Nissl stain and cell counting was done in CA1, CA2 and CA3 regions of the hippocampus. The results show that the animals on IF diet had significantly less SE induction and significantly longer duration of latent period (the period of epileptogenesis) was seen in IF-IF group compared to the AL-AL group. The severity of SRS was significantly more in AL-IF (PfS) compared to the AL-IF (PSE) group. These results indicate that IF diet can make rats resistant to the induction of SE and can prolong the process of epileptogenesis. The results of the histological study show that the number of pyramidal neurons was statistically less in CA1, CA2 and CA3 of the hippocampus in the experimental groups compared to the control groups. However, IF regimen could not protect the hippocampal neurons against the excitotoxic injury caused by a prolonged SE. We conclude that IF regimen can significantly influence various behavioral characteristics of pilocarpine model of TLE. Further studies can elaborate the exact mechanisms as well as its possible role in the treatment of human TLE.
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Affiliation(s)
- Neda Parinejad
- Department of Physiology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Islamic Republic of Iran
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99
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Leng J, Jiang L, Chen H, Zhang X. Brain-derived neurotrophic factor and electrophysiological properties of voltage-gated ion channels during neuronal stem cell development. Brain Res 2009; 1272:14-24. [DOI: 10.1016/j.brainres.2009.03.048] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2009] [Revised: 03/14/2009] [Accepted: 03/17/2009] [Indexed: 01/19/2023]
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100
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Lee CH, Hwang IK, Lee IS, Yoo KY, Choi JH, Lee BH, Won MH. Differential immunoreactivity of microglial and astrocytic marker protein in the hippocampus of the seizure resistant and sensitive gerbils. J Vet Med Sci 2009; 70:1405-9. [PMID: 19122416 DOI: 10.1292/jvms.70.1405] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the present study, we compared differences in ionized calcium-binding adapter molecule 1 (Iba-1) and glial fibrillary acidic protein (GFAP) immunoreactivities for microglia and astrocytes, respectively, in the hippocampus of the seizure-resistant (SR) and seizure-sensitive (SS) gerbils. The density of Iba-1 immunoreactive microglia in the hippocampal CA1 region (CA1) and dentate gyrus (DG) of the SS gerbil was higher than that in the SR gerbil, and many Iba-1 immunoreactive microglia in the SS gerbil were hypertrophied in morphology. In contrast, we could not find significant difference in the density of GFAP immunoreactive astrocytes between the SR and SS gerbils. This result indicates that Iba-1 immunoreactive microglia in CA1 and DG of the SS gerbil are activated compared to those in the SR gerbil.
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Affiliation(s)
- Choong Hyun Lee
- Department of Anatomy and Neurobiology, Hallym University, South Korea
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