Role of oxidative stress in refractory epilepsy: evidence in patients and experimental models

Immunohistochemical Study of Antioxidant Enzymes Regulated by Nrf2 in the Models of Epileptic Seizures (KA and PTZ)

Epilepsy is a neurological disorder characterized by recurrent spontaneous seizures due to an imbalance between cerebral excitability and inhibition, with a tendency towards uncontrolled excitability. Epilepsy has been associated with oxidative and nitrosative stress due to prolonged neuronal hyperexcitation and loss neurons during seizures. The experimental animal models report level of ATP diminished and increase in lipid peroxidation, catalase, and glutathione altered activity in the brain. We studied the immunohistochemical expression and localization of antioxidant enzymes GPx, SOD, and CAT in the rat brains treated with KA and PTZ. A significant decrease was observed in the number of immunoreactive cells to GPx, without significant changes for SOD and CAT in KA-treated rats, and decrease in the number of immunoreactive cells to SOD, without significant changes for GPx and only CAT in PTZ-treated rats. Evident immunoreactivity of GPx, SOD, and CAT was observed mainly in astrocytes and neurons of the hippocampal brain region in rats exposed at KA; similar results were observed in rats treated with PTZ at the first hours. These results provide evidence supporting the role of activation of the Nrf2 antioxidant system pathway against oxidative stress effects in the experimental models of epileptic seizures.

Expression of nuclear factor-erythroid 2-related factor 2 in rat brain following the administration of kainic acid and pentylenetetrazole

Epilepsy is a neurological disorder of the central nervous system characterized by hypersynchronized neuronal activity and has been associated with oxidative stress. Oxidative stress interferes with the expression of genes as well as transcriptional factors such as nuclear factor-erythroid 2-related factor 2 (Nrf2). We evaluated the expression of Nrf2 in the rat brain in treated with kainic acid (KA) and pentylenetetrazole (PTZ). Nrf2 immunoreactivity was observed in astrocytes of the hippocampal region in rats exposed at KA. Nrf2 expression was increased significantly in rats with KA and PTZ. These results provide evidence that the increased expression of Nrf2 is part of the mechanism against KA and PTZ toxicity.

[Oxidative stress in epilepsy]

This article contains an analysis of clinical and experimental studies in which oxidative stress is considered as a possible mechanism in the pathogenesis of epilepsy. Oxidative stress occurs as a result of brain damage after epileptic seizures and may later cause epileptogenesis. Patients with epilepsy showed a high level of lipid peroxidation markers, while the activity of antioxidant defense system was low. The level of oxidative stress was shown to be significantly higher in epileptics with associated mental disorders and in patients with refractory epilepsy. Further study of oxidative stress in epilepsy may play the key role in the treatment of this disease.

Investigating owner use of dietary supplements in dogs with idiopathic epilepsy

Epilepsy is the most common chronic neurological disorder in dogs. Some diets have been shown to have a positive impact upon the seizure activity in dogs with idiopathic epilepsy (IE), while other diets and dietary supplements (DS), although marketed as providing health benefits, lack conclusive scientific evidence on their actual beneficial effects. A web-based owner questionnaire was designed to assess how and why owners of dogs with IE use different dietary regimes and DS. The study cohort, with 297 valid responses, consisted mainly of pure-breed (82.5%) male neutered (52.9%) dogs. Over two-thirds of owners (67.7%) changed their dog's diet after their dog received a diagnosis of IE. Nearly half of the owners (45.8%) reported giving DS, the most common being coconut oil or derived medium-chain triglyceride oil (71.3%). Some owner justifications of DS use included improvement of seizure frequency (88.2%), seizure severity (61.8%) and protection from potential drug side effects (62.5%). Many owners give DS to their dog with IE. The pharmacokinetic properties of anti-epileptic drugs, such as efficacy, absorption and clearance can be influenced by other medications, diets and possibly by DS. We propose that use of DS should be considered and monitored by veterinary surgeons in epilepsy management.

Differential Gene Expression Profile Induced by Valproic Acid (VPA) in Pediatric Epileptic Patients

Epilepsy is a neuronal disease that affects up to 70 million people worldwide. The development of effective therapies to combat childhood epilepsy requires early biomarkers. Here, we performed a whole-genome microarray analysis in blood cells to identify genes differentially expressed between epileptic and epileptic valproic acid (VPA)-treated children versus normal children to obtain information about the gene expression to help us to understand genetic aspects of this disease. We found that the most significant differentially expressed genes were related to the transcriptional factor cAMP-response element binding protein (CREB) that is overexpressed in children with epilepsy compared with normal children, and 6 and 12 months of VPA treatment reversed several of these changes. Interestingly, leukocyte-associated immunoglobulin-like receptor 1 (LAIR1), a type I transmembrane glycoprotein that binds collagen proteins and contains CREB binding sites, was one of the more up-regulated genes in epileptic patients, and treatment with VPA strongly reversed its up-regulation. CREB up-regulates genes related to epilepsy; here, we suggest that LAIR1 could activate CREB, and together, they trigger epilepsy. After VPA treatment, LAIR1 repressed genes by disrupting the functional LAIR1–CREB complex, resulting in successful treatment. A functional microarray analysis offers new information that could open novel avenues of research in biomarker discovery, which may be useful for the early identification of children with a predisposition to epilepsy.

Oxidative Stress in Patients with Drug Resistant Partial Complex Seizure

Oxidative stress (OS) has been implicated as a pathophysiological mechanism of drug-resistant epilepsy, but little is known about the relationship between OS markers and clinical parameters, such as the number of drugs, age onset of seizure and frequency of seizures per month. The current study’s aim was to evaluate several oxidative stress markers and antioxidants in 18 drug-resistant partial complex seizure (DRPCS) patients compared to a control group (age and sex matched), and the results were related to clinical variables. We examined malondialdehyde (MDA), advanced oxidation protein products (AOPP), advanced glycation end products (AGEs), nitric oxide (NO), uric acid, superoxide dismutase (SOD), glutathione, vitamin C, 4-hydroxy-2-nonenal (4-HNE) and nitrotyrosine (3-NT). All markers except 4-HNE and 3-NT were studied by spectrophotometry. The expressions of 4-HNE and 3-NT were evaluated by Western blot analysis. MDA levels in patients were significantly increased (p ≤ 0.0001) while AOPP levels were similar to the control group. AGEs, NO and uric acid concentrations were significantly decreased (p ≤ 0.004, p ≤ 0.005, p ≤ 0.0001, respectively). Expressions of 3-NT and 4-HNE were increased (p ≤ 0.005) similarly to SOD activity (p = 0.0001), whereas vitamin C was considerably diminished (p = 0.0001). Glutathione levels were similar to the control group. There was a positive correlation between NO and MDA with the number of drugs. The expression of 3-NT was positively related with the frequency of seizures per month. There was a negative relationship between MDA and age at onset of seizures, as well as vitamin C with seizure frequency/month. We detected an imbalance in the redox state in patients with DRCPS, supporting oxidative stress as a relevant mechanism in this pathology. Thus, it is apparent that some oxidant and antioxidant parameters are closely linked with clinical variables.

Protective effect of Fructus corni polysaccharide on hippocampal tissues and its relevant mechanism in epileptic rats induced by lithium chloride-pilocarpine

The aim of the present study was to investigate the potential effect of Fructus corni polysaccharide (PFC) on the hippocampus tissues in epileptic rats induced by lithium chloride-pilocarpine, and to explore the underlying mechanism. The epileptic rat models were established using lithium chloride-pilocarpine treatment. According to the dosage of PFC, the rat models were divided into three groups: The low-dose (100 mg/kg/day), middle-dose (200 mg/kg/day) and high-dose (300 mg/kg/day) groups. The intervention for rat models lasted for 24 days. Subsequently, the production levels of reactive oxygen species (ROS) and malondialdehyde (MDA), the activity of superoxide dismutase (SOD), the mitochondrial membrane potential and the expressions of mitogen-activated protein kinase [P-38, Janus kinase (JNK) and extracellular signal-regulated kinase 1/2], cytochrome-C and caspase-3 in hippocampal tissues were detected. In addition, the structure of the CA-1 region of the hippocampus was also observed. Compared with the control group, the production levels of ROS were increased and the mitochondrial membrane potential was decreased in the hippocampus tissues of rats in the model group. In addition, in the model group, it was observed that MDA content was increased, SOD activity was decreased, and the expressions of phosphorylated (p)-p38, p-JNK, cytochrome-c and caspase-3 were increased, compared with the control group. Furthermore, those abnormal variations of the indicators were reversed by the intervention of PFC. These findings suggest that PFC can ameliorate the secondary damage to the hippocampi of epileptic rats, and that the anti-oxidation and -apoptosis effects of PFC may be associated with the mechanism that provides a protective effect for hippocampal tissues.

Differential Effect of Acute Iron Overload on Oxidative Status and Antioxidant Content in Regions of Rat Brain

The hypothesis of this study is that the cerebral cortex, hippocampus, and striatum of the rat brain are differentially affected in terms of oxidative stress and antioxidant capacity by acute Fe overload because Fe is distributed in a heterogeneous fashion among different regions and cells of the brain. The effects on the lipophilic and hydrophilic cellular environment were compared between regions and with the whole brain. A single dose of Fe-dextran increased Fe deposits, reaching a maximum after 6 hr. Both in whole brain and in cortex region, the ascorbyl/ascorbate content ratio was increased after 6 hr of Fe administration, while in striatum and hippocampus, there was no significant changes after Fe overload. Total thiol content decreased in whole brain and cortex, while there were no significant changes in striatum and hippocampus after Fe overload. The content of α-tocopherol (α-T), whether measured in the whole brain or in the isolated regions, did not change following Fe treatment. Lipid radical (LR•) generation rate after Fe-dextran overload only increased in the cortex region. The LR•/α-T content ratio was increased by Fe treatment in cortex but not in the whole brain, striatum, or hippocampus, in agreement with the study tested hypothesis.

Oxidative Stress in the Development of Genetic Generalised Epilepsy: An Observational Study in Southern Indian Population

Introduction

Oxidative stress resulting from excessive generation of Reactive Oxygen Species (ROS) plays a significant role in neurodegeneration associated with seizures/epilepsy.

Aim

To evaluate oxidative stress markers and antioxidant enzymes in Genetic Generalised Epilepsy (GGE) and to know the extent of oxidative stress induced by Anti-Epileptic Drugs (AEDs) with the time duration of treatment.

Materials and Methods

In this case-control study, 310 GGE patients (male:female=203:107), who were on AED treatment (n=235) and 75 untreated patients (male:female=49:26) along with 310 age and sex matched healthy controls were recruited. Oxidative stress markers such as Nitric Oxide (NO), Malondialdehyde (MDA) and antioxidant enzyme activities namely Superoxide Dismutase (SOD), Glutathione Peroxidase (GPx) and Catalase (CAT) were measured spectrophotometrically.

Results

Significantly higher levels of serum NO, MDA and low levels of plasma Total Antioxidant Capacity (TAC) were found in patients as compared to controls (p<0.001) whereas erythrocyte SOD, CAT and GPx activities were found to be significantly low in patients when compared to the control group (p<0.001). Statistically significant higher levels of NO, MDA and lower levels of SOD, CAT and TAC were observed in patients subgroup, who were on AEDs for more than >5 years compared to other groups (≤ 1 year and 1-≤ 5 years) (p=0.02, p=0.01, p=0.001, p=0.01 and p=0.05 respectively). Further, significant increase in the levels of NO, MDA and decreased activities of SOD, CAT were found in treated patients compared to untreated patients (p<0.05) denoting that additional oxidative stress induced by AEDs which results in seizure recurrence and drug intractability.

Conclusion

Our study demonstrated that GGE patients have additional oxidative stress due to AEDs and decreased antioxidant enzyme activities causing an imbalance between oxidant and antioxidant status, which might contribute to the pathogenesis of GGE.

Testosterone Upregulates the Expression of Mitochondrial ND1 and ND4 and Alleviates the Oxidative Damage to the Nigrostriatal Dopaminergic System in Orchiectomized Rats

Testosterone deficiency, as a potential risk factor for aging and aging-related neurodegenerative disorders, might induce mitochondrial dysfunction and facilitate the declines of the nigrostriatal dopaminergic system by exacerbating the mitochondrial defects and increasing the oxidative damage. Thus, how testosterone levels influence the mitochondrial function in the substantia nigra was investigated in the study. The present studies showed that testosterone deficiency impaired the mitochondrial function in the substantia nigra and induced the oxidative damage to the substantia nigra as well as the deficits in the nigrostriatal dopaminergic system. Of four mitochondrial respiratory chain complexes, castration of male rats reduced the activity of mitochondrial complex I and downregulated the expression of ND1 and ND4 of 7 mitochondrial DNA- (mtDNA-) encoded subunits of complex I in the substantia nigra. Supplements of testosterone propionate to castrated male rats ameliorated the activity of mitochondrial complex I and upregulated the expression of mitochondrial ND1 and ND4. These results suggest an important role of testosterone in maintaining the mitochondrial function in the substantia nigra and the vulnerability of mitochondrial complex I to testosterone deficiency. Mitochondrial ND1 and ND4, as potential testosterone targets, were implicated in the oxidative damage to the nigrostriatal dopaminergic system.

Alleviation of Oxidative Damage and Involvement of Nrf2-ARE Pathway in Mesodopaminergic System and Hippocampus of Status Epilepticus Rats Pretreated by Intranasal Pentoxifylline

The current studies were aimed at evaluating the efficacy of intranasal pentoxifylline (Ptx) pretreatment in protecting mesodopaminergic system and hippocampus from oxidative damage of lithium-pilocarpine induced status epilepticus (SE) and the involvement of nuclear factor erythroid 2-related factor 2- (Nrf2-) antioxidant response elements pathway. Pentoxifylline was administered to rats intranasally or intraperitoneally 30 minutes before inducing SE. Our results showed the impaired visuospatial memory, the defected mesodopaminergic system, and the oxidative damage and the transient activation of Nrf2 in SE rats. The transient activation of Nrf2 in SE rats was enhanced by Ptx pretreatment, which was followed by the upregulation of heme oxygenase-1 and NAD(P)H:quinone oxidoreductase-1. Ptx pretreatment to SE rats significantly suppressed the epileptic seizures, decreased the levels of lipid peroxide and malondialdehyde, and elevated the ratio of reduced glutathione/oxidized glutathione. Compared with intraperitoneal injection, intranasal Ptx delivery completely restored the visuospatial memory and the activity of mesodopaminergic system in SE rats. Intranasal administration of Ptx may hopefully become a noninvasive, painless, and easily administered option for epileptic patients.

Polyunsaturated fatty acid supplementation for drug-resistant epilepsy

BACKGROUND

An estimated 1% to 3% of all individuals will receive a diagnosis of epilepsy during their lives, which corresponds to approximately 50 million affected people worldwide. The real prevalence is possibly higher because epilepsy is underreported in developing countries. Although most will achieve adequate control of their disease though the use of medication, approximately 25% to 30% of all those with epilepsy are refractory to pharmacological treatment and will continue to have seizures despite the use of two or more agents in adequate dosages. Over the last decade, researchers have tested the use of polyunsaturated fatty acid (PUFA) supplements for the treatment of refractory epilepsy, with inconsistent results. There have also been some concerns about the use of omega-3 PUFA compounds because they reduce platelet aggregation and could, in theory, cause bleeding.

OBJECTIVES

To assess the effectiveness and tolerability of omega-3 polyunsaturated fatty acids (eicosapentaenoic acid-EPA and docosahexanoic acid-DHA) in the control of seizures in people with refractory epilepsy.

SEARCH METHODS

We searched the Cochrane Epilepsy Group Specialised Register (from inception up to November 2015), the Cochrane Central Register of Controlled Trials (CENTRAL) (2015, issue 11), MEDLINE (1948 to November 2015), EMBASE (1980 to November 2015), SCOPUS (1823 to November 2015); LILACS (Literatura Latino-Americana e do Caribe de Informação em Ciências da Saúde) (1982 to November 2015); ClinicalTrials.gov; World Health Organization (WHO) International Clinical Trials Registry Platform (November 2015). No language restrictions were imposed. We contacted study authors for additional and unpublished information and screened the reference lists of retrieved citations for potentially eligible studies not identified through the electronic search.

SELECTION CRITERIA

All randomised and quasi-randomised studies using PUFAs for the treatment of drug-resistant epilepsy.

DATA COLLECTION AND ANALYSIS

Two review authors were involved in study selection, data extraction and quality assessment of the included trials. The following outcomes were assessed: seizure freedom, seizure reduction, improvement in quality of life, potential adverse effects, gastrointestinal effects, drop-out rates and changes in plasma lipid profile. Primary analyses were by intention to treat.

MAIN RESULTS

Eight studies were identified as potentially relevant; three fulfilled the selection criteria and were included in the review. Two placebo-controlled, double blind trials involving adult participants were conducted in developed countries, while one placebo-controlled, single blind trial involving children was conducted in a developing country (Egypt). Bromfield 2008 randomised 27 American adults to receive 2.2 g/day of omega-3 PUFAs (EPA:DHA in a 3:2 ratio) or placebo. Yuen 2005 randomised 58 people in the UK to approximately 1.7 g/day omega-3 PUFAs (1g EPA and 0.7g DHA) or placebo. Reda 2015 randomised 70 Egyptian children to receive 3 ml/day of 1200 mg fish oil (providing 0.24 g DHA and 0.36 g EPA) or placebo. The three studies recruited a total of 155 subjects (85 adults and 70 children); 78 of them (43 adults and 35 children) were randomised to PUFAs and 77 (42 adults and 35 children) to placebo. All participants were followed for up to 12 weeks. Seizure freedom was reported by only one study, with a high risk of bias, involving exclusively children. The risk estimate for this outcome was significantly higher in the children receiving PUFA compared to the control group (risk ratio (RR) 20.00, 95% confidence interval (CI) 2.84 to 140.99, 1 study, 70 children). Similarly, PUFA supplementation was associated with a significant difference in the proportion of children with at least 50% reduction in seizure frequency (RR 33.00 95% CI 4.77 to 228.15, 1 study with a high risk of bias, 70 children). However, this effect was not observed when the data from two studies including adult participants were pooled (RR 0.57, 95% CI 0.19 to 1.75, I² 0%, 2 studies, 78 participants, low-quality evidence). One of our three primary outcomes (adverse effects related to bleeding) was not assessed in any of the studies included in this review. There were no significant differences between the PUFA and control groups in relation to gastrointestinal effects (RR 0.78, 95% CI 0.32 to 1.89, 2 studies, 85 participants, low-quality evidence).Supplementation with PUFA did not produce significant differences in mean frequency of seizures, quality of life or other side effects.

AUTHORS' CONCLUSIONS

In view of the limited number of studies and small sample sizes, there is not enough evidence to support the use of PUFA supplementation in people with refractory epilepsy. More trials are needed to assess the benefits of PUFA supplementation in the treatment of drug-resistant epilepsy.

Neuroprotective mechanism of Coenzyme Q10 (CoQ10) against PTZ induced kindling and associated cognitive dysfunction: Possible role of microglia inhibition

BACKGROUND

Neuroinflammation, oxidative stress and mitochondrial dysfunction play a significant role to explain the pathophysiology of epilepsy. Neuroinflammation through microglia activation has been documented in epileptogenesis. Compounds which inhibit activation of glial cells have been suggested as one of the treatment approaches for the effective treatment of epilepsy. The present study has been designed to investigate the role of coenzyme Q10 and its interaction with minocycline (microglia inhibitor) against pentylenetetrazol (PTZ) induced kindling epilepsy.

METHODS

Laca mice received Coenzyme Q10 and minocycline for a period of 29 days. PTZ (40mg/kg ip) injection has been given on alternate days. Various behavioural parameters (kindling score and elevated plus maze), biochemical parameters (lipid peroxidation, superoxide dismutase, reduced glutathione, catalase, nitrite and acetylcholinesterase) and mitochondrial enzyme complex activities of (I, II and IV) were assessed in the discrete areas of the brain.

RESULTS

Administration of a subconvulsive dose of PTZ (40mg/kg) repeatedly increased significantly kindling score, oxidative damage and impaired mitochondrial enzyme complex activities (I, II and IV) and pro-inflammatory marker (TNF-α) as compared to naive animals. Coenzyme Q10 (10, 20 and 40mg/kg) and minocycline (50 and 100mg/kg) for a duration of 29days significantly attenuated kindling score, reversed oxidative damage, TNF-α and restored mitochondrial enzyme complex activities (I, II and IV) as compared to control. Further, combinations of CoQ10 (10, 20mg/kg) with minocycline (50 and 100mg/kg) significantly modulate the protective effect of CoQ10 which was significant as compared to their effect per se in PTZ treated animals.

CONCLUSION

The present study suggests the involvement of microglia inhibition in the protective effect of CoQ10 in PTZ induced kindling in mice.

Antiepileptic drugs affect lipid oxidative markers- neuroprostanes and F2-dihomo-isoprostanes- in patients with epilepsy: differences among first-, second-, and third-generation drugs by UHPLC-QqQ-MS/MS

This work show that treatment with new-generation AEDs reduces the excretion of NeuroPs/F₂-dihomo-IsoPs to values similar to those in the control group, indicating a positive effect of these AEDs on the antioxidant status of epileptic patients.

Detection and Quantification of Free Radicals in Peroxisomal Disorders: A Comparative Study with Oxidative Stress Parameters

INTRODUCTION

Free radicals have been thought to participate in pathogenesis of peroxisomal disorders.

OBJECTIVE

The aim of the work is to detect free oxide radicals in blood of patients with peroxisomal disorders and to study their relation with various oxidative stress parameters.

MATERIALS AND METHODS

Twenty patients with peroxisomal disorders and 14 age and sex matched healthy subjects were included in the study. Patients with peroxisomal disorders were subdivided according to diagnosis into peroxisomal biogenesis disorders and single enzyme deficiency. Oxidative stress was evaluated in both patients and control subjects by assessment of free radicals, malondialdehyde, nitric oxide metabolites and superoxide dismutase.

RESULTS

There was increase in free radicals, malondialdehyde, nitric oxide metabolites in patients compared with control subjects. However, there was decrease in superoxide dismutase levels in patients compared with control subjects.

CONCLUSION

We concluded that there is excess free radicals production accompanied with decrease in antioxidant defenses in patients with peroxisomal disorders. These results strongly support a role of free radicals in the pathophysiology of peroxisomal disorders and strengthen the importance of oxidative stress phenomenon in peroxisomal disorders pathogenesis.

Metallothionein expression in the rat brain following KA and PTZ treatment

Epilepsy is a neurological disorder that has been associated with oxidative stress therefore epilepsy models have been develop such as kainic acid and pentylenetetrazol are usually used to understanding of the molecular mechanisms of this disease. We examined the metallothionein expression in rat brains of treated with kainic acid and pentylenetetrazol. Increase in metallothionein and nitrotirosyne immunoreactivity of both seizures epilepsy models was observed. Moreover, we show a significant increase on levels of MT expression. These results suggest that the increase of metallothionein expression is related with kainic acid and pentylenetetrazol treatments as response to damage mediated by oxidative stress.

Dihomo-isoprostanes-nonenzymatic metabolites of AdA-are higher in epileptic patients compared to healthy individuals by a new ultrahigh pressure liquid chromatography-triple quadrupole-tandem mass spectrometry method

Oxidative stress is a biochemical state in which reactive oxygen species are generated and it has been associated with pathological states including epilepsy. Therein, neuroprostanes (NeuroPs) and dihomo-isoprostanes (Dihomo-IsoPs)-a series of compounds formed nonenzymatically through free radical-induced DHA, n-6 DPA, and AdA peroxidation-are implicated in the pathophysiological status of various human neurological diseases. A new, robust, and selective analytical method for the determination of 10 NeuroPs/Dihomo-IsoPs in human urine, using solid-phase extraction and UHPLC-QqQ-MS/MS in the multiple reaction monitoring mode (using a negative electrospray ionization interface), was developed. Nine NeuroPs/Dihomo-IsoPs were identified in 15 epileptic patients, matched with healthy volunteers. Among them, 17-F2t-Dihomo-IsoP, Ent-7(R)-7-F2t-Dihomo-IsoP, and Ent-7-epi-7-F2t-Dihomo-IsoP, derived from adrenic acid (AdA), were significantly higher in epileptic patients than in healthy volunteers. The validated method provided a high-throughput assay with a limit of detection and limit of quantification for each analyte of 0.10-5.90ngmL(-1) and 0.15-11.81ngmL(-1), respectively. The intra- and interday variations were lower than 14%. Dihomo-IsoPs have been considered as potential markers of epilepsy for the first time and their measurement may increase the understanding of the role of oxidative stress in neurological diseases, in intra vitam studies. The present study highlights a potential role of Dihomo-IsoPs as biomarkers in persons with epilepsy, though its mechanisms and possible implications should be the subject of further investigations.

Seizure-induced oxidative stress in temporal lobe epilepsy

An insult to the brain (such as the first seizure) causes excitotoxicity, neuroinflammation, and production of reactive oxygen/nitrogen species (ROS/RNS). ROS and RNS produced during status epilepticus (SE) overwhelm the mitochondrial natural antioxidant defense mechanism. This leads to mitochondrial dysfunction and damage to the mitochondrial DNA. This in turn affects synthesis of various enzyme complexes that are involved in electron transport chain. Resultant effects that occur during epileptogenesis include lipid peroxidation, reactive gliosis, hippocampal neurodegeneration, reorganization of neural networks, and hypersynchronicity. These factors predispose the brain to spontaneous recurrent seizures (SRS), which ultimately establish into temporal lobe epilepsy (TLE). This review discusses some of these issues. Though antiepileptic drugs (AEDs) are beneficial to control/suppress seizures, their long term usage has been shown to increase ROS/RNS in animal models and human patients. In established TLE, ROS/RNS are shown to be harmful as they can increase the susceptibility to SRS. Further, in this paper, we review briefly the data from animal models and human TLE patients on the adverse effects of antiepileptic medications and the plausible ameliorating effects of antioxidants as an adjunct therapy.

The role of flavonoids on oxidative stress in epilepsy

Backgrounds. Oxidative stress can result from excessive free-radical production and it is likely implicated as a possible mechanism involved in the initiation and progression of epileptogenesis. Flavonoids can protect the brain from oxidative stress. In the central nervous system (CNS) several flavonoids bind to the benzodiazepine site on the GABA_A-receptor resulting in anticonvulsive effects. Objective. This review provides an overview about the role of flavonoids in oxidative stress in epilepsy. The mechanism of action of flavonoids and its relation to the chemical structure is also discussed. Results/Conclusions. There is evidence that suggests that flavonoids have potential for neuroprotection in epilepsy.

Erythropoietin as a new therapeutic opportunity in brain inflammation and neurodegenerative diseases

Highly expressed Erythropoietin Receptor (EPO-R) has been detected in several nonhematopoietic hypoxic cells, including cells from different brain areas in response to many different types of cell injury. In brain, hypoxia-ischemia (HI) can induce a wide spectrum of biologic responses, where inflammation and apoptosis are the main protagonists. Inflammation, as a primary brain insult, can induce a chronic hypoxic condition, producing the continuous cycle of inflammation-hypoxia that increases the apoptotic-cell number. It has also been demonstrated that administration of erythropoietin (EPO) prevented the neuronal death induced by HI, as well as the induction of lipid peroxidation in the hippocampus in a rodent model of Alzheimer's disease. Anti-apoptotic, anti-inflammatory, anti-oxidant, and/or cell-proliferative effects of EPO, have been observed in all type of cells expressing EPO-R, resulting in a potential tool for neuroprotection, neuroreparation, or neurogenesis of brain damaged areas. The nasal route is an alternative way of drugs administration that has been successfully exploited for bypassing the blood brain barrier, and subsequently delivering EPO and other molecules to central nervous system. Intranasal administration of EPO could be a new therapeutic opportunity in several brain damages that includes hypoxia, inflammation, neurodegenerative process, and apoptosis.

Oxidative stress associated with neuronal apoptosis in experimental models of epilepsy

Epilepsy is considered one of the most common neurological disorders worldwide. Oxidative stress produced by free radicals may play a role in the initiation and progression of epilepsy; the changes in the mitochondrial and the oxidative stress state can lead mechanism associated with neuronal death pathway. Bioenergetics state failure and impaired mitochondrial function include excessive free radical production with impaired synthesis of antioxidants. This review summarizes evidence that suggest what is the role of oxidative stress on induction of apoptosis in experimental models of epilepsy.

The potential of antiseizure drugs and agents that act on novel molecular targets as antiepileptogenic treatments

A major goal of contemporary epilepsy research is the identification of therapies to prevent the development of recurrent seizures in individuals at risk, including those with brain injuries, infections, or neoplasms; status epilepticus; cortical dysplasias; or genetic epilepsy susceptibility. In this review we consider the evidence largely from preclinical models for the antiepileptogenic activity of a diverse range of potential therapies, including some marketed antiseizure drugs, as well as agents that act by immune and inflammatory mechanisms; reduction of oxidative stress; activation of the mammalian target of rapamycin or peroxisome proliferator-activated receptors γ pathways; effects on factors related to thrombolysis, hematopoesis, and angiogenesis; inhibition of 3-hydroxy-3-methylglutaryl-coenzyme A reducatase; brain-derived neurotrophic factor signaling; and blockade of α2 adrenergic and cannabinoid receptors. Antiepileptogenesis refers to a therapy of which the beneficial action is to reduce seizure frequency or severity outlasting the treatment period. To date, clinical trials have failed to demonstrate that antiseizure drugs have such disease-modifying activity. However, studies in animal models with levetiracetam and ethosuximide are encouraging, and clinical trials with these agents are warranted. Other promising strategies are inhibition of interleukin 1β signaling by drugs such as VX-765; modulation of sphingosine 1-phosphate signaling by drugs such as fingolimod; activation of the mammalian target of rapamycin by drugs such as rapamycin; the hormone erythropoietin; and, paradoxically, drugs such as the α2 adrenergic receptor antagonist atipamezole and the CB1 cannabinoid antagonist SR141716A (rimonabant) with proexcitatory activity. These approaches could lead to a new paradigm in epilepsy drug therapy where treatment for a limited period prevents the occurrence of spontaneous seizures, thus avoiding lifelong commitment to symptomatic treatment.

Modulation of cytokine production by drugs with antiepileptic or mood stabilizer properties in anti-CD3- and anti-Cd40-stimulated blood in vitro

Increased cytokine production possibly due to oxidative stress has repeatedly been shown to play a pivotal role in the pathophysiology of epilepsy and bipolar disorder. Recent in vitro and animal studies of valproic acid (VPA) report antioxidative and anti-inflammatory properties, and suppression of interleukin (IL)-6 and tumor necrosis factor (TNF)-α. We tested the effect of drugs with antiepileptic or mood stabilizer properties, namely, primidone (PRM), carbamazepine (CBZ), levetiracetam (LEV), lamotrigine (LTG), VPA, oxcarbazepine (OXC), topiramate (TPM), phenobarbital (PB), and lithium on the production of the following cytokines in vitro: interleukin (IL)-1β, IL-2, IL-4, IL-6, IL-17, IL-22, and TNF-α. We performed a whole blood assay with stimulated blood of 14 healthy female subjects. Anti-human CD3 monoclonal antibody OKT3, combined with 5C3 antibody against CD40, was used as stimulant. We found a significant reduction of IL-1 and IL-2 levels with all tested drugs other than lithium in the CD3/5C3-stimulated blood; VPA led to a decrease in IL-1β, IL-2, IL-4, IL-6, IL-17, and TNF-α production, which substantiates and adds knowledge to current hypotheses on VPA's anti-inflammatory properties.

Modulation of antioxidant enzymatic activities by certain antiepileptic drugs (valproic acid, oxcarbazepine, and topiramate): evidence in humans and experimental models

It is estimated that at least 100 million people worldwide will suffer from epilepsy at some point in their lives. This neurological disorder induces brain death due to the excessive liberation of glutamate, which activates the postsynaptic N-methyl-D-aspartic acid (NMDA) receptors, which in turn cause the reuptake of intracellular calcium (excitotoxicity). This excitotoxicity elicits a series of events leading to nitric oxide synthase (NOS) activation and the generation of reactive oxygen species (ROS). Several studies in experimental models and in humans have demonstrated that certain antiepileptic drugs (AEDs) exhibit antioxidant effects by modulating the activity of various enzymes associated with this type of stress. Considering the above-mentioned data, we aimed to compile evidence elucidating how AEDs such as valproic acid (VPA), oxcarbazepine (OXC), and topiramate (TPM) modulate oxidative stress.

An update on oxidative stress-mediated organ pathophysiology

Exposure to environmental pollutants and drugs can result in pathophysiological situations in the body. Research in this area is essential as the knowledge on cellular survival and death would help in designing effective therapeutic strategies that are needed for the maintenance of the normal physiological functions of the body. In this regard, naturally occurring bio-molecules can be considered as potential therapeutic targets as they are normally available in commonly consumed foodstuffs and are thought to have minimum side effects. This review article describes the detailed mechanisms of oxidative stress-mediated organ pathophysiology and the ultimate fate of the cells either to survive or to undergo necrotic or apoptotic death. The mechanisms underlying the beneficial role of a number of naturally occurring bioactive molecules in oxidative stress-mediated organ pathophysiology have also been included in the review. The review provides useful information about the recent progress in understanding the mechanism(s) of various types of organ pathophysiology, the complex cross-talk between these pathways, as well as their modulation in stressed conditions. Additionally, it suggests possible therapeutic applications of a number of naturally occurring bioactive molecules in conditions involving oxidative stress.

Autism and dietary therapy: case report and review of the literature

We report the history of a child with autism and epilepsy who, after limited response to other interventions following her regression into autism, was placed on a gluten-free, casein-free diet, after which she showed marked improvement in autistic and medical symptoms. Subsequently, following pubertal onset of seizures and after failing to achieve full seizure control pharmacologically she was advanced to a ketogenic diet that was customized to continue the gluten-free, casein-free regimen. On this diet, while still continuing on anticonvulsants, she showed significant improvement in seizure activity. This gluten-free casein-free ketogenic diet used medium-chain triglycerides rather than butter and cream as its primary source of fat. Medium-chain triglycerides are known to be highly ketogenic, and this allowed the use of a lower ratio (1.5:1) leaving more calories available for consumption of vegetables with their associated health benefits. Secondary benefits included resolution of morbid obesity and improvement of cognitive and behavioral features. Over the course of several years following her initial diagnosis, the child's Childhood Autism Rating Scale score decreased from 49 to 17, representing a change from severe autism to nonautistic, and her intelligence quotient increased 70 points. The initial electroencephalogram after seizure onset showed lengthy 3 Hz spike-wave activity; 14 months after the initiation of the diet the child was essentially seizure free and the electroencephalogram showed only occasional 1-1.5 second spike-wave activity without clinical accompaniments.

Aberrant free radical biology is a unifying theme in the etiology and pathogenesis of major human diseases

The seemingly disparate areas of oxygen toxicity, radiation exposure, and aging are now recognized to share a common feature—the aberrant production and/or removal of biologically derived free radicals and other reactive oxygen and nitrogen species (ROS/RNS). Advances in our understanding of the effects of free radicals in biology and medicine have been, and continue to be, actively translated into clinically tractable diagnostic and therapeutic applications. This issue is dedicated to recent advances, both basic discoveries and clinical applications, in the field of free radicals in biology and medicine. As more is understood about the proximal biological targets of aberrantly produced or removed reactive species, their sensors, and effectors of compensatory response, a great deal more will be learned about the commonalities in mechanisms underlying seemingly disparate disease states. Together with this deeper understanding, opportunities will arise to devise rational therapeutic interventions to decrease the incidence and severity of these diseases and positively impact the human healthspan.