Antiepileptogenic Potential Research Articles

Penı̇sı̇lı̇n ile Oluşturulan Deneysel Epilepsi Modelinde Seftrı̇aksonun Etkı̇sı̇: Elektrofı̇zyolojı̇k Bı̇r Çalışma

Introduction: Epilepsy is a set of chronic neurological disorders characterized by seizures associated with abnormal and uncontrolled neuronal activity of the brain. Glutamate is the main excitatory neurotransmitter in the central nervous system. Excitatory amino acid transporter-2 (EAAT2), one of the major glutamate transporters, is responsible for total glutamate intake. Ceftriaxone is a β-lactam antibiotic that increases EAAT-2 expression and functional activity. This study aims to investigate the effects of ceftriaxone on penicillin-induced epileptiform activity by using electrocorticography (ECoG) in anesthetized rats.
 Materials and Methods: In this study, 35 Wistar male rats were used. The rats were divided into five groups of 7. In group 1, 2.5 μL 500 IU of penicillin intracranially (i.c.) and 1 ml saline solution and intraperitoneally (i.p.) were given, respectively. In group 2, 200 mg/kg, i.p. of ceftriaxone was administered 30 minutes after penicillin. In group 3, 400 mg/kg of ceftriaxone was administered i.p. 30 minutes after penicillin. 500 mg/kg of sodium valproate was administered i.p. following 30 minutes of penicillin in group 4. In group 5, 400 mg/kg, i.p. of ceftriaxone and 500 mg/kg, i.p. of sodium valproate were administered 30 minutes after penicillin. The rats were placed in a stereotaxic device after the procedure, and electrocorticogram recordings were captured for 180 minutes.
 Results: The acute treatment of ceftriaxone reduced spike-wave frequency and spike-wave amplitude of penicillin-induced epileptiform activity in the rats. 
 Conclusion: These findings suggest that acute ceftriaxone had an anticonvulsant effect on penicillin-induced focal onset epileptic activity. Ceftriaxone may has an anti-epileptogenic potential.

Anti-epileptogenic effect of FC99 and resveratrol.

Toll-like receptor 3 (TLR3), plays an important role in the development of epilepsy after brain insults. Previously, TLR3 deficiency in a pilocarpine model of temporal lobe epilepsy (TLE) was shown to reduce mortality, spontaneous recurrent seizures (SRS) and neuroinflammation. We hypothesized that pharmacological inhibition of TLR3 would reduce epileptogenesis following status epilepticus. We show that Resveratrol and FC99, two TLR3 blockers, demonstrate anti-epileptogenic effects in a pilocarpine model of TLE. While both Resveratrol and FC99 were previously shown to benefit in other pathologies, neither of these blockers had been proposed for the treatment of epilepsy. Our results provide substantial evidence to the importance of TLR3 inhibition in the prevention of epilepsy and specifically highlighting FC99 as a promising novel anti-epileptic drug. We anticipate our data to be a starting point for further studies assessing the anti-epileptogenic potential of FC99 and other TLR3 blockers, paving the way for pharmacological interventions that prevent epileptogenesis.

Evaluation of the Anxiolytic and Anti-Epileptogenic Potential of Lactuca Serriola Seed Using Pentylenetetrazol-Induced Kindling in Mice and Metabolic Profiling of Its Bioactive Extract.

This study aimed to assess the potential of Lactuca serriola (Asteraceae) seed n-hexane, chloroform, methanol, and aqueous extracts as anticonvulsant, sedative, anticonvulsant and antiepileptic agents in Swiss albino mice. Different doses of each extract were evaluated for the anxiolytic potential using the hole-board, the elevated plus maze and the light/dark test. A phenobarbitone-induced sleep test was employed for the evaluation of sedative potential. Acute anticonvulsant activity was evaluated by picrotoxin and strychnine-induced convulsion models. All extracts significantly reduced the number of head dips where n-hexane extract (400 mg/kg) showed 96.34% reduction in the tendency of head dipping when compared with the control. Mice treated with extracts preferred elevated plus maze open arms and were shown to lack open arms evasion, especially n-hexane extract (400 mg/kg)-which showed 456.14%-increased the duration of open arm stay with the respective control group. By reducing sleep latency and greatly lengthening sleep duration, L. serriola enhanced the effects of barbiturate-induced sleep. A significant increase in convulsion latency and decrease in convulsions induced by picrotoxin and strychnine duration was observed in all extract-treated groups. All the extracts exhibited anti-epileptogenic potential as the seizure score in pentylenetetrazol (PTZ)-induced kindling in mice was reduced significantly. Maximum protection was afforded by chloroform extract that reduced the seizure score by 79.93% compared with the PTZ group. Chloroform executed antioxidant effect by elevating super oxide dismutase (SOD) by 126%, catalase (CAT) by 83.53%, total glutathione (tGSH) by 149%, and reducing malondialdhyde (MDA) levels by 36.49% in the brain tissues that is further consolidated by histopathological examination. Metabolic profiling of the most active chloroform extract using Gas chromatography coupled with mass showed the presence of 16 compounds. This anti-epileptic activity was further confirmed via in silico molecular modelling studies in the active site Gamma-aminobutyric acid aminotransferase (GABA-AT) where all of the tested metabolites illustrated a potent inhibitory potential towards GABA-AT with hexadecanoic acid, 15-methyl-, methyl ester followed by octadecanoic acid, methyl ester showed the best fitting. The results indicated the possible anxiolytic and anti-epileptogenic potential of the plant and further consolidated the ethnopharmacological use of L. serriola seeds.

No persistent effects of intracerebral curcumin administration on seizure progression and neuropathology in the kindling rat model for temporal lobe epilepsy

Curcumin is known for its neuroprotective, anti-inflammatory and anti-oxidant properties and has been investigated as a potential therapeutic drug for Temporal Lobe Epilepsy (TLE). We previously found anti-epileptogenic properties of curcumin in an in vitro brain slice model for epileptogenesis, and inhibitory effects on the MAPK-pathway in vivo after intracerebrally applying curcumin in post-status epilepticus rats. Here, we investigated whether the intracerebral application of curcumin could be anti-epileptogenic in the rapid kindling rat model for TLE. Curcumin or vehicle was injected directly into the brain through an intracerebral ventricular cannula at 5 consecutive days during the kindling process. Kindling consisted of repeated electrical stimulations of the angular bundle (12 times a day with a 30min interval) every other day, until rats were fully kindled or until 36 stimulations were administered. One week after kindling acquisition, additional kindling stimulations were applied in a re-test in the absence of curcumin- or vehicle treatment. Curcumin-treated rats required more stimulations compared to vehicle-treated rats to reach Racine stage IV seizures, indicating that curcumin delayed seizure development. However, it did not prevent the fully kindled state as shown in the re-test. Increasing the dose of curcumin did not produce a delay in seizure development. Immunohistochemistry showed that kindling produced cell loss, astrogliosis, mossy fiber sprouting and neurogenesis in the dentate gyrus, which were not different between vehicle- and curcumin-treated groups. Although curcumin's effects on neuropathology were not detected and the delay of kindling development was transient, the data warrant further exploration of its anti-epileptogenic potential using formulations that further increase its bioavailability.

Selected Molecular Targets for Antiepileptogenesis.

The term epileptogenesis defines the usually durable process of converting normal brain into an epileptic one. The resistance of a significant proportion of patients with epilepsy to the available pharmacotherapy prompted the concept of a causative treatment option consisting in stopping or modifying the progress of epileptogenesis. Most antiepileptic drugs possess only a weak or no antiepileptogenic potential at all, but a few of them appear promising in this regard; these include, for example, eslicarbazepine (a sodium and T-type channel blocker), lamotrigine (a sodium channel blocker and glutamate antagonist) or levetiracetam (a ligand of synaptic vehicle protein SV2A). Among the approved non-antiepileptic drugs, antiepileptogenic potential seems to reside in losartan (a blocker of angiotensin II type 1 receptors), biperiden (an antiparkinsonian drug), nonsteroidal anti-inflammatory drugs, antioxidative drugs and minocycline (a second-generation tetracycline with anti-inflammatory and antioxidant properties). Among other possible antiepileptogenic compounds, antisense nucleotides have been considered, among these an antagomir targeting microRNA-134. The drugs and agents mentioned above have been evaluated in post-status epilepticus models of epileptogenesis, so their preventive efficacy must be verified. Limited clinical data indicate that biperiden in patients with brain injuries is well-tolerated and seems to reduce the incidence of post-traumatic epilepsy. Exceptionally, in this regard, our own original data presented here point to c-Fos as an early seizure duration, but not seizure intensity-related, marker of early epileptogenesis. Further research of reliable markers of early epileptogenesis is definitely needed to improve the process of designing adequate antiepileptogenic therapies.

Early intervention with levetiracetam prevents the development of cortical hyperexcitability and spontaneous epileptiform activity in two models of neurotrauma in rats

This study examined the antiepileptogenic potential of the antiseizure drug (ASD) levetiracetam (LEV) using the in vitro traumatized-slice and in vivo controlled cortical impact (CCI) models of traumatic brain injury (TBI) in rats when administered early after the injury. For the in vitro model, acute coronal slices (400–450 μm) of rat neocortex (P21–32) were injured via a surgical cut that separated the superficial layers from the deeper regions. Persistent stimulus-evoked epileptiform activity developed within 1–2 h after trauma. In randomly selected slices, LEV (500 μM) was bath-applied for 1 h starting immediately or delayed by 30–80 min after injury. Treated and untreated slices were examined for epileptiform activity via intracellular and extracellular recordings. For the in vivo model, rats (P24–32) were subjected to a non-penetrating, focal, CCI injury targeting the neocortex (5.0 mm diameter; 2.0 mm depth). Immediately after injury, rats were given either a single dose of LEV (60–150 mg/kg, i.p.) or the saline vehicle. At 2–3 weeks after the injury, ex vivo cortical slices were examined for epileptiform activity. The results from the traumatized-slice experiments showed that in vitro treatment with LEV within 60 min of injury significantly reduced (> 50%) the proportion of slices that exhibited stimulus-evoked epileptiform activity. LEV treatment also increased the stimulus intensity required to trigger epileptiform bursts in injured slices by 2–4 fold. Consistent with these findings, LEV treatment of CCI-injured rats (n = 15) significantly reduced the proportion of animals that exhibited spontaneous and stimulus-evoked epileptiform bursts in ex vivo cortical slices compared to saline-treated controls (n = 15 rats), and also significantly increased the stimulus intensity required to evoke epileptiform bursts. These results suggest that early administration of LEV has the potential to prevent or reduce posttraumatic epileptogenesis and that there may be a narrow therapeutic window for successful prophylactic intervention.

Cognition and memory impairment attenuation via reduction of oxidative stress in acute and chronic mice models of epilepsy using antiepileptogenic Nux vomica

Ethnopharmacological relevance Processed Nux vomica seed extracts and homeopathic medicinal preparations (HMPs) are widely used in traditional Indian and Chinese medicine for respiratory, digestive, neurological and behavioral disorders. Antioxidant property of Nux vomica is well known and recent investigation has highlighted the anticonvulsant potential of its homeopathic formulation. Aim of the studyTo explore the anticonvulsant and antiepileptogenic potential of Nux vomica HMPs (6CH, 12CH and 30CH potency) in pentylenetetrazole (PTZ) induced acute and chronic experimental seizure models in mice and investigate their effects on cognition, memory, motor activity and oxidative stress markers in kindled animals. Materials and methodsAcute seizures were induced in the animals through 70 mg/kg (i.p.) administration of PTZ followed by the evaluation of latency and duration of Generalized tonic-clonic seizures (GTCS). Subconvulsive PTZ doses (35 mg/kg, i.p.) induced kindling in 29 days, which was followed by assessment of cognition, memory and motor impairment through validated behavioral techniques. The status of oxidative stress was estimated through measurement of MDA, GSH and SOD. ResultsHMPs delayed the latency and reduced the duration of GTCS in acute model signifying possible regulation of GABAergic neurotransmission. Kindling was significantly hindered by the HMPs that justified the ameliorated cognition, memory and motor activity impairment. The HMPs attenuated lipid peroxidation by reducing MDA level and strengthened the antioxidant mechanism by enhancing the GSH and SOD levels in the kindled animals. ConclusionsNux vomica HMPs showed anticonvulsant and antiepileptogenic potency in acute and chronic models of epilepsy. The test drugs attenuated behavioral impairment and reduced the oxidative stress against PTZ induced kindling owing to which they can be further explored for their cellular and molecular mechanism(s).

Effects of rapamycin and curcumin on inflammation and oxidative stress in vitro and in vivo \u2014 in search of potential anti-epileptogenic strategies for temporal lobe epilepsy

BackgroundPrevious studies in various rodent epilepsy models have suggested that mammalian target of rapamycin (mTOR) inhibition with rapamycin has anti-epileptogenic potential. Since treatment with rapamycin produces unwanted side effects, there is growing interest to study alternatives to rapamycin as anti-epileptogenic drugs. Therefore, we investigated curcumin, the main component of the natural spice turmeric. Curcumin is known to have anti-inflammatory and anti-oxidant effects and has been reported to inhibit the mTOR pathway. These properties make it a potential anti-epileptogenic compound and an alternative for rapamycin.MethodsTo study the anti-epileptogenic potential of curcumin compared to rapamycin, we first studied the effects of both compounds on mTOR activation, inflammation, and oxidative stress in vitro, using cell cultures of human fetal astrocytes and the neuronal cell line SH-SY5Y. Next, we investigated the effects of rapamycin and intracerebrally applied curcumin on status epilepticus (SE)—induced inflammation and oxidative stress in hippocampal tissue, during early stages of epileptogenesis in the post-electrical SE rat model for temporal lobe epilepsy (TLE).ResultsRapamycin, but not curcumin, suppressed mTOR activation in cultured astrocytes. Instead, curcumin suppressed the mitogen-activated protein kinase (MAPK) pathway. Quantitative real-time PCR analysis revealed that curcumin, but not rapamycin, reduced the levels of inflammatory markers IL-6 and COX-2 in cultured astrocytes that were challenged with IL-1β. In SH-SY5Y cells, curcumin reduced reactive oxygen species (ROS) levels, suggesting anti-oxidant effects. In the post-SE rat model, however, treatment with rapamycin or curcumin did not suppress the expression of inflammatory and oxidative stress markers 1 week after SE.ConclusionsThese results indicate anti-inflammatory and anti-oxidant properties of curcumin, but not rapamycin, in vitro. Intracerebrally applied curcumin modified the MAPK pathway in vivo at 1 week after SE but failed to produce anti-inflammatory or anti-oxidant effects. Future studies should be directed to increasing the bioavailability of curcumin (or related compounds) in the brain to assess its anti-epileptogenic potential in vivo.

The anti-epileptogenic and cognition enhancing effect of novel 1-[4-(4-benzo [1, 3] dioxol-5-ylmethyl-piperazin-1-yl)-phenyl]-3-phenyl-urea (BPPU) in pentylenetetrazole induced chronic rat model of epilepsy.

Epilepsy is a chronic neurological disorder which affects 65 million worldwide population and characterized by recurrent seizure in epileptic patients. Recently, we reported a novel piperonylpiperazine derivative, BPPU "1-[4-(4-benzo [1,3]dioxol-5-ylmethyl-piperazin-1-yl)- phenyl]-3-phenyl-urea'' as a potent anticonvulsant agent. BPPU has shown excellent anticonvulsant activity in various in-vivo seizure models along with good anti-depressant activity. In this report, we have deeply examined the anti-epileptogenic potential of BPPU in pentylenetetrazole (PTZ) induced kindling model and BPPU effectively reduced seizure episodes in kindled animals upto 35 days. Further, neuroprotective potential of BPPU against PTZ induced neurodegeneration has also been evaluated in hippocampus as well as cortex region by histopathological and immunohistochemical studies. Epileptic patients generally suffer from a range of cognitive impairments. Therefore, the cognition enhancing effect of BPPU was also measured by using well known social recognition test, novel object recognition test, light/dark test and open field test in kindled rat model as well as scopolamine induced memory deficit mice model. Results indicated that BPPU successfully improved cognition deficits in both models. Thus, BPPU appeared as a potent anti-epileptic agent which has also capability to improve cognition decline associated with epilepsy.

Neurobiological Correlates of Alpha-Tocopherol Antiepileptogenic Effects and MicroRNA Expression Modulation in a Rat Model of Kainate-Induced Seizures

Seizure-triggered maladaptive neural plasticity and neuroinflammation occur during the latent period as a key underlying event in epilepsy chronicization. Previously, we showed that α-tocopherol (α-T) reduces hippocampal neuroglial activation and neurodegeneration in the rat model of kainic acid (KA)-induced status epilepticus (SE). These findings allowed us to postulate an antiepileptogenic potential for α-T in hippocampal excitotoxicity, in line with clinical evidence showing that α-T improves seizure control in drug-resistant patients. To explore neurobiological correlates of the α-T antiepileptogenic role, rats were injected with such vitamin during the latent period starting right after KA-induced SE, and the effects on circuitry excitability, neuroinflammation, neuronal death, and microRNA (miRNA) expression were investigated in the hippocampus. Results show that in α-T-treated epileptic rats, (1) the number of population spikes elicited by pyramidal neurons, as well as the latency to the onset of epileptiform-like network activity recover to control levels; (2) neuronal death is almost prevented; (3) down-regulation of claudin, a blood–brain barrier protein, is fully reversed; (4) neuroinflammation processes are quenched (as indicated by the decrease of TNF-α, IL-1β, GFAP, IBA-1, and increase of IL-6); (5) miR-146a, miR-124, and miR-126 expression is coherently modulated in hippocampus and serum by α-T. These findings support the potential of a timely intervention with α-T in clinical management of SE to reduce epileptogenesis, thus preventing chronic epilepsy development. In addition, we suggest that the analysis of miRNA levels in serum could provide clinicians with a tool to evaluate disease evolution and the efficacy of α-T therapy in SE.

Modification of the natural progression of epileptogenesis by means of biperiden in the pilocarpine model of epilepsy

Brain injuries are often associated with the later development of epilepsy. Evidence suggests that morphological and functional changes occur in the remaining neural tissue during a silent (or latent) period in which no seizures are expressed. It is believed that this silent (reorganization) period may provide a therapeutic window for modifying the natural history of disease progression. Here we provide evidence that biperiden, a muscarinic anticholinergic agent, is able to alter disease progression in an animal model of epilepsy. We observed that biperiden was capable of slowing the manifestation of the first spontaneous epileptic seizure and effectively reduced the severity and number of recurrent, spontaneous epileptic seizures during the animals’ lifespan. Biomolecular (microdialysis) and electrophysiological (extracellular field recordings) studies determined that biperiden was capable of elevating the threshold of hippocampal excitability, thereby making the hippocampal glutamatergic pathways less responsive to stimuli when high concentrations of potassium were used in vivo or in vitro. Notably, there was no hindrance of long-term memory or learning (a potential problem given the amnestic nature of biperiden). We conclude that biperiden has antiepileptogenic potential and may represent an opportunity for the prevention of post-traumatic epilepsy.

Sitagliptin enhances the neuroprotective effect of pregabalin against pentylenetetrazole-induced acute epileptogenesis in mice: Implication of oxidative, inflammatory, apoptotic and autophagy pathways

The current investigation aimed at studying the anti-epileptogenic effect of sitagliptin. The possible effect of the drug in combination with pregabalin in pentylenetetrazole (PTZ)- induced seizures was studied. In addition, the postulated mechanisms that could mediate such effect were explored namely, suppression of oxidative stress and neuro-inflammatory markers, autophagy and apoptosis. Seven days prior to PTZ (60 mg/kg, sc) injection, mice were treated with sitagliptin (5, 15, and 60 mg/kg, twice daily, orally) or pregabalin (30 mg/kg, once daily, orally) or their combination. At the end of the experiment, several parameters were assessed including: oxidative/nitro-oxidative stress such as superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GP-x) catalase (CAT), and lipid peroxidation assessed as malondialdehyde (MDA), nitrate/nitrite (NOx), 3-nitrotyrosine (3-NT). Seizure latency was evaluated. Neuronal damage was also assessed by performing tissue staining by hematoxylin and eosin, estimating hippocampus level of glutamate, gamma-aminobutyric acid (GABA), glial fibrillary acidic protein (GFAP) and brain-derived neurotrophic factor (BDNF). Also, markers for inflammation, autophagy and apoptosis were measured, nuclear factor erythroid-derived 2- like 2 (Nrf2), nuclear factor kappa-B (NF-κB), phosphatidylethanolamine-conjugated form of microtubule-associated protein light chain-3 (LC3-II), casapase-3, Bcl-2-like protein 4 (BAX) and glucagon like peptide-1 (GLP-1) activity. Sitagliptin significantly suppressed epileptogenesis in PTZ-induced seizures. Sitagliptin counteracted neuronal damage and all biochemical, and histo-chemical alteration induced by PTZ. Also, a more significant protective effect was observed after combination with pregabalin. This study is indicative for the antiepileptogenic potential of sitagliptin with or without pregabalin in the PTZ model of epilepsy which is likely to be through its effect on antioxidant, anti-apoptotic and autophagic pathways.

Rapamisinin Sıçanlarda Penisilinle Oluşturulmuş Epileptiform Aktivite Üzerine Etkisi: Bir Elektrofizyolojik Çalışma

Aim: Approximately fifty million people in the world suffer from epilepsy, and a large part of these patients are resistant to antiepileptic drugs discovered so far. In addition, side effect profiles of these drugs are very wide. Rapamycin that is an inhibitor of mammalian target of rapamycin (mTOR) has antineoplastic, aging-retarding, and anti-inflammatory effects. The studies regarding the effects of mTOR on nervous system have shown that it has neuro-protective effects. Moreover, it has been reported that use of rapamycin reduces epileptic seizures in tuberous sclerosis patients. In this study we aimed to investigate acute effects of the mTOR inhibitor rapamycin on penicillin-induced experimental epilepsy in rats. Materials and Methods : In this study, a model of forty adult male Wistar rats with penicillin induced experimental epilepsy was used. The forty rats were divided into five groups, which were saline group, solvent (dimethylsulfoxide) group, and 0.1 mg/kg, 0.4 mg/kg and 0.8 mg/kg rapamycin groups. All substances were administered intraperitoneally. After the administration of 1.25 g/kg urethane for anesthesia, the left part of each rat’s skull was opened and electrodes were placed on the brain. Electrocorticography recording was initiated. Penicillin was intracortically administered two hours after the administration of rapamycin. After the administration of penicillin, electrocorticographic data were recorded for another two hours. Results : In rapamycin-treated rat groups, administration of 0.4 mg/kg and 0.8 mg/kg rapamycin significantly reduced epileptic spike-wave frequency and amplitude of epileptiform activity. However, when compared in terms of latency no significant difference was found between the groups. Discussion and Conclusion: Acute administration of rapamycin reduced spike-wave frequency and spike-wave amplitude of penicillin-induced epileptiform activity in the rats, and these findings indicate that rapamycin has an antiepileptogenic potential.

Brivaracetam: Rationale for discovery and preclinical profile of a selective SV2A ligand for epilepsy treatment.

Despite availability of effective antiepileptic drugs (AEDs), many patients with epilepsy continue to experience refractory seizures and adverse events. Achievement of better seizure control and fewer side effects is key to improving quality of life. This review describes the rationale for the discovery and preclinical profile of brivaracetam (BRV), currently under regulatory review as adjunctive therapy for adults with partial-onset seizures. The discovery of BRV was triggered by the novel mechanism of action and atypical properties of levetiracetam (LEV) in preclinical seizure and epilepsy models. LEV is associated with several mechanisms that may contribute to its antiepileptic properties and adverse effect profile. Early findings observed a moderate affinity for a unique brain-specific LEV binding site (LBS) that correlated with anticonvulsant effects in animal models of epilepsy. This provided a promising molecular target and rationale for identifying selective, high-affinity ligands for LBS with potential for improved antiepileptic properties. The later discovery that synaptic vesicle protein 2A (SV2A) was the molecular correlate of LBS confirmed the novelty of the target. A drug discovery program resulted in the identification of anticonvulsants, comprising two distinct families of high-affinity SV2A ligands possessing different pharmacologic properties. Among these, BRV differed significantly from LEV by its selective, high affinity and differential interaction with SV2A as well as a higher lipophilicity, correlating with more potent and complete seizure suppression, as well as a more rapid brain penetration in preclinical models. Initial studies in animal models also revealed BRV had a greater antiepileptogenic potential than LEV. These properties of BRV highlight its promising potential as an AED that might provide broad-spectrum efficacy, associated with a promising tolerability profile and a fast onset of action. BRV represents the first selective SV2A ligand for epilepsy treatment and may add a significant contribution to the existing armamentarium of AEDs.

Antiepileptogenic effects of borneol in pentylenetetrazole-induced kindling in mice.

Borneol, a bicyclic monoterpene, can easily cross the blood brain barrier and was found to possess gamma amino butyric acid (GABA) modulatory effect. The present study was aimed at investigating the antiepileptogenic effect of borneol in the pentylenetetrazole (PTZ)-induced kindling besides its ability to suppress oxidative stress and neuroinflammatory marker, glial fibrillary acidic protein (GFAP). Repeated administration of a subconvulsive dose of PTZ (35 mg/kg, i.p.) on every alternate day for 4 weeks produced kindling in mice. Borneol (5, 10, and 25 mg/kg, i.p.) and diazepam (1 mg/kg, i.p.) were given as a pretreatment prior to each PTZ injection during the progression of kindling. Oxidative stress parameters such as superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT), and lipid peroxidation (LPO) were assessed at the end of the study. Neuronal damage was assessed by hematoxylin and eosin staining technique. GFAP was also evaluated in the hippocampus region of the brain by using immunohistochemistry. Borneol significantly suppressed the process of epileptogenesis in PTZ-kindled mice. The biochemical alterations induced by PTZ kindling were ameliorated in borneol-treated animals which was indicated by decreased LPO and increased SOD, GSH, CAT levels. The distinct neuronal damage observed in the kindled group was counteracted by borneol. Furthermore, it decreased the levels of GFAP which was manifested by reduced immunostaining. The above results are suggestive of the antiepileptogenic potential of borneol in the PTZ-induced kindling model of epilepsy, and thus, it could be a prospective molecule in the treatment of epilepsy.

Microglial ROS production in an electrical rat post-status epilepticus model of epileptogenesis

Reactive oxygen species and inflammatory signaling have been identified as pivotal pathophysiological factors contributing to epileptogenesis. Considering the development of combined anti-inflammatory and antioxidant treatment strategies with antiepileptogenic potential, a characterization of the time course of microglial reactive oxygen species generation during epileptogenesis is of major interest. Thus, we isolated microglia cells and analyzed the generation of reactive oxygen species by flow cytometric analysis in an electrical rat post-status epilepticus model.Two days post status epilepticus, a large-sized cell cluster exhibited a pronounced response with excessive production of reactive oxygen species upon stimulation with phorbol-myristate-acetate. Neither in the latency phase nor in the chronic phase with spontaneous seizures a comparable cell population with induction of reactive oxygen species was identified.We were able to demonstrate in the electrical rat post-status-epilepticus model, that microglial ROS generation reaches a peak after the initial insult, is only marginally increased in the latency phase, and returns to control levels during the chronic epileptic phase. The data suggest that a combination of anti-inflammatory and radical scavenging approaches might only be beneficial during a short time window after an epileptogenic brain insult.

Disease modification in epilepsy: from animal models to clinical applications.

Several relevant animal models of epileptogenesis and biomarkers have emerged for evaluating the antiepileptogenic potential of an investigational drug. Although several promising candidate compounds and approaches have been identified in these preclinical models, no treatment has yet successfully navigated the path from preclinical efficacy to clinical validation. Until such an agent can move from preclinical proof of concept to clinical success, the need remains to continually develop and optimize preclinical models and clinical trial design in an effort to guide potential clinical investigations. This review describes several available models of disease modification and/or epileptogenesis, preclinical studies in these models and potential biomarkers useful for evaluating the efficacy of a potential therapeutic agent in the preclinical setting. The results that emerge from such efforts may then guide the clinical evaluation of a candidate compound. This review discusses some of the known limitations and hurdles to moving compounds found effective in these models to clinical practice, in the hope that knowledge of this information will facilitate the design and conduct of clinical studies and effectively facilitate the identification of a first-in-class disease-modifying or antiepileptogenic agent.

The AMPA receptor antagonist NBQX exerts anti-seizure but not antiepileptogenic effects in the intrahippocampal kainate mouse model of mesial temporal lobe epilepsy

The AMPA receptor subtype of glutamate receptors, which mediates fast synaptic excitation, is of primary importance in initiating epileptiform discharges, so that AMPA receptor antagonists exert anti-seizure activity in diverse animal models of partial and generalized seizures. Recently, the first AMPA receptor antagonist, perampanel, was approved for use as adjunctive therapy for the treatment of resistant partial seizures in patients. Interestingly, the competitive AMPA receptor antagonist NBQX has recently been reported to prevent development of spontaneous recurrent seizures (SRS) in a neonatal seizure model in rats, indicating the AMPA antagonists may exert also antiepileptogenic effects. This prompted us to evaluate competitive (NBQX) and noncompetitive (perampanel) AMPA receptor antagonists in an adult mouse model of mesial temporal lobe epilepsy. In this model, SRS develop after status epilepticus (SE) induced by intrahippocampal injection of kainate. Focal electrographic seizures in this model are resistant to several major antiepileptic drugs. In line with previous studies, phenytoin was not capable of blocking such seizures in the present experiments, while they were markedly suppressed by NBQX and perampanel. However, perampanel was less tolerable than NBQX in epileptic mice, so that only NBQX was subsequently tested for antiepileptogenic potential. When mice were treated over three days after kainate-induced SE with NBQX (20 mg/kg t.i.d.), no effect on development or frequency of seizures was found in comparison to vehicle controls. These results suggest that AMPA receptor antagonists, while being effective in suppressing resistant focal seizures, are not exerting antiepileptogenic effects in an adult mouse model of partial epilepsy.

Characterization of anticonvulsant and antiepileptogenic potential of thymol in various experimental models

The present study was to investigate the anticonvulsant and antiepileptogenic potential of thymol. Anticonvulsant activity of thymol (5-100mg/kgi.p.) was studied using maximal electroshock, pentylenetetrazole (PTZ), strychnine and 4-aminopyridine (4-AP) models. Thymol at the selected dose was also studied for its effect on locomotion. Antiepileptogenic property of thymol (5-25mg/kg) was evaluated using PTZ-induced kindling model along with its effect on malondialdehyde and glutathione levels. Thymol (50 and 100mg/kg, i.p.) showed anticonvulsant activity against maximal electroshock and pentylenetetrazole (66.66 and 83.33% protection at 50 and 100mg/kg, respectively) model but not against strychnine and 4-aminopyridine models. Thymol exhibited decreased locomotor activity in dose-dependent manner at the same dose range. Thymol at the dose of (25mg/kg, i.p.) significantly decreased the seizure score, increased glutathione levels and decreased malondialdehyde levels in pentylenetetrazole-induced kindling model. Thymol exhibited significant anticonvulsant and antiepileptogenic property.

Long-term effect of everolimus on epilepsy and growth in children under 3 years of age treated for subependymal giant cell astrocytoma associated with tuberous sclerosis complex

BackgroundTuberous sclerosis complex (TSC) is a genetic disorder characterized by increased mammalian target of rapamycin (mTOR) activation and growth of benign tumors in several organs throughout the body. In young children with TSC, drug-resistant epilepsy and subependymal giant cell astrocytomas (SEGAs) present the most common causes of mortality and morbidity. There are also some reports on the antiepileptic and antiepileptogenic potential of mTOR inhibitors in TSC. However, the data on everolimus efficacy and safety in young children are very limited. AimsTo show the long-term safety data and the effect of everolimus treatment on epilepsy in children under the age of 3 who received everolimus for SEGAs associated with TSC. MethodsWe present the results of everolimus treatment in 8 children under the age of 3 who participated in EXIST-1 study. Five patients presented with active, drug-resistant epilepsy at baseline. The mean follow-up is 35 months (33–38 months) and all children are still on treatment. ResultsIn 6 out of 8 children, at least a 50% reduction in SEGA volume was observed. In 1 child with drug-resistant epilepsy, everolimus treatment resulted in cessation of seizures and in 2 other children, at least a 50% reduction in the number of seizures was noted. The incidence of adverse events (AE) was similar to that observed in older children and adults. ConclusionsThis study suggests that everolimus is effective and safe in infants and young children with epilepsy and SEGA associated with TSC and offers a valuable treatment option.