Experience With Lacosamide in a Series of Children With Drug-Resistant Focal Epilepsy

We report our pediatric experience with lacosarnide, a new antiepileptic drug, approved by the US Food and Drug Administration as adjunctive therapy in focal epilepsy in patients more than 17 years old. We retrospectively reviewed charts for lacosamide use and seizure frequency outcome in patients with focal epilepsy (Wilcoxon signed rank test). Sixteen patients (7 boys) were identified (median dose 275 mg daily, 4.7 mg/kg daily; mean age 14.9 years, range 8-21 years). Patients were receiving a median of 2 antiepileptic drugs (interquartile range [IQR] 1.7-3) in addition to having undergone previous epilepsy surgery (n = 3), vagus nerve stimulation (n = 9), and ketogenic diet (n = 3). Causes included structural (encephalomalacia and diffuse encephalitis, 1 each; stroke in 2) and genetic abnormalities (Aarskog and Rett syndromes, 1 each) or cause not known (n = 10). Median seizure frequency at baseline was 57 per month (IQR 7-75), and after a median follow-up of 4 months (range 1-13 months) of receiving lacosamide, it was 12.5 per month (IQR 3-75), (P < 0.01). Six patients (37.5%; 3 seizure free) were classified as having disease that responded to therapy (>= 50% reduction seizure frequency) and 10 as having disease that did not respond to therapy (<50% in 3; increase in 1; unchanged in 6). Adverse events (tics, behavioral disturbance, seizure worsening, and depression with suicidal ideation in 1 patient each) prompted lacosamide discontinuation in 4/16 (25%). This retrospective study of 16 children with drug-resistant focal epilepsy demonstrated good response to adjunctive lacosamide therapy (median seizure reduction of 39.6%; 37.5% with >= 50% seizure reduction) without severe adverse events. (C) 2011 Elsevier Inc. All rights reserved.

Temporal lobe epilepsy and social behavior: An animal model

Social behavior depends on the integrity of social brain circuitry. The temporal lobe is an important part of the social brain, and manifests morphological and functional alterations in autism spectrum disorders (ASD). Rats with temporal lobe epilepsy (TLE), induced with pilocarpine, were subjected to a social discrimination test that has been used to investigate potential animal models of ASD, and the results were compared with those for the control group. Rats with TLE exhibited fewer social behaviors than controls. No differences were observed in nonsocial behavior between groups. The results suggest an important role for the temporal lobe in regulating social behaviors. This animal model might be used to explore some questions about ASD pathophysiology. (c) 2008 Elsevier Inc. All rights reserved.

Reactive oxygen species generated by NADPH oxidase are involved in neurodegeneration in the pilocarpine model of temporal lobe epilepsy

Reactive oxygen species (ROS) appear to be involved in several neurodegenerative disorders. We tested the hypothesis that oxidative stress could have a role in the hippocampal neurodegeneration observed in temporal lobe epilepsy induced by pilocarpine. We first determined the spatio-temporal pattern of ROS generation, by means of detection with dihydroethidium oxidation, in the CA1 and CA3 areas and the dentate gyrus of the dorsal hippocampus during status epilepticus induced by pilocarpine. Fluoro-Jade B assays were also performed to detect degenerating neurons. ROS generation was increased in CA1, CA3 and the dentate gyrus after pilocarpine-induced seizures, which was accompanied by marked cell death. Treatment of rats with a NADPH oxidase inhibitor (apocynin) for 7 days prior to induction of status epilepticus was effective in decreasing both ROS production (by an average of 20%) and neurodegeneration (by an average of 61%). These results suggest an involvement of ROS generated by NADPH oxidase in neuronal death in the pilocarpine model of epilepsy. (C) 2010 Elsevier Ireland Ltd. All rights reserved.

The sleep-wake cycle in adult rats following pilocarpine-induced temporal lobe epilepsy

The relationship between sleep and epilepsy is both complex and clinically significant. Temporal lobe epilepsy (TLE) influences sleep architecture, while sleep plays an important role in facilitating and/or inhibiting possible epileptic seizures. The pilocarpine experimental model reproduces several features of human temporal lobe epilepsy and is one of the most widely used models in basic research. The aim of the present study was to characterize, behaviorally and electrophysiologically, the phases of sleep-wake cycles (SWC) in male rats with pilocarpine-induced epilepsy. Epileptic rats presented spikes in all phases of the SWC as well as atypical cortical synchronization during attentive wakefulness and paradoxical sleep. The architecture of the sleep-wake phases was altered in epileptic rats, as was the integrity of the SWC. Because our findings reproduce many relevant features observed in patients with epilepsy, this model is suitable to study sleep dysfunction in epilepsy. (C) 2009 Elsevier Inc. All rights reserved.

Alteration of purinergic P2X(4) and P2X(7) receptor expression in rats with temporal-lobe epilepsy induced by pilocarpine

Although ATP and P2X receptor activity have been lately associated with epilepsy, little is known regarding their exact roles in epileptogenesis. Temporal-lobe epilepsy (TLE) in rat was induced by pilocarpine in order to study changes of hippocampal P2X(2), P2X(4) and P2X(7) receptor expression during acute, latent or chronic phases of epilepsy. During acute and chronic phases increased P2X(7) receptor expression was principally observed in glial cells and glutamatergic nerve terminals, suggesting participation of this receptor in the activation of inflammatory and excitotoxic processes during epileptogenesis. No significant alterations of hippocampal P2X(2) and P2X(4) receptor expression was noted during the acute or latent phase when compared to the control group, indicating that these receptors are not directly involved with the initiation of epilepsy. However, the reduction of hippocampal P2X(4) receptor immunostaining in the chronic phase could reflect neuronal toss or decreased GABAergic signaling. (C) 2008 Elsevier B.V. All rights reserved.

Higher evening antiepileptic drug dose for nocturnal and early-morning seizures

We describe 17 children with nocturnal or early-morning seizures who were switched to a proportionally higher evening dose of antiepileptic drugs and were retrospectively reviewed for seizure outcome and side effects. Of 10 children with unknown etiology, clinical presentation was consistent with nocturnal frontal lobe epilepsy (NFLE) in 5 and benign epilepsy with centrotemporal spikes (BECTS) in 3. After a mean follow-up of 5.3 months, 15 patients were classified as responders: 11 of these became seizure free (5 NFLE, 1 BECTS, 5 with structural lesions) and 4 (2 BECTS, 2 with structural lesions) experienced 75-90% reductions in seizures. Among two nonresponders, seizures in one had failed to resolve with epilepsy surgery. Nine subjects (53%) received monotherapy after dose modification, and none presented with worsening of seizures. Two complained of transient side effects (fatigue/somnolence). Differential dosing led to seizure freedom in 64.7% (11/17) of patients, and 88.2% (15/17) experienced >= 50% reductions in seizures. (C) 2010 Elsevier Inc. All rights reserved.

Clinical and molecular delineation of the 17q21.31 microdeletion syndrome

Background: The chromosome 17q21.31 microdeletion syndrome is a novel genomic disorder that has originally been identified using high resolution genome analyses in patients with unexplained mental retardation. Aim: We report the molecular and/or clinical characterisation of 22 individuals with the 17q21.31 microdeletion syndrome. Results: We estimate the prevalence of the syndrome to be 1 in 16 000 and show that it is highly underdiagnosed. Extensive clinical examination reveals that developmental delay, hypotonia, facial dysmorphisms including a long face, a tubular or pear-shaped nose and a bulbous nasal tip, and a friendly/amiable behaviour are the most characteristic features. Other clinically important features include epilepsy, heart defects and kidney/urologic anomalies. Using high resolution oligonucleotide arrays we narrow the 17q21.31 critical region to a 424 kb genomic segment (chr17: 41046729-41470954, hg17) encompassing at least six genes, among which is the gene encoding microtubule associated protein tau (MAPT). Mutation screening of MAPT in 122 individuals with a phenotype suggestive of 17q21.31 deletion carriers, but who do not carry the recurrent deletion, failed to identify any disease associated variants. In five deletion carriers we identify a <500 bp rearrangement hotspot at the proximal breakpoint contained within an L2 LINE motif and show that in every case examined the parent originating the deletion carries a common 900 kb 17q21.31 inversion polymorphism, indicating that this inversion is a necessary factor for deletion to occur (p< 10(25)). Conclusion: Our data establish the 17q21.31 microdeletion syndrome as a clinically and molecularly well recognisable genomic disorder.

The non-coding RNA BC1 is down-regulated in the hippocampus of Wistar Audiogenic Rat (WAR) strain after audiogenic kindling

The aim of this study was to identify molecular pathways involved in audiogenic seizures in the epilepsy-prone Wistar Audiogenic Rat (WAR). For this, we used a suppression-subtractive hybridization (SSH) library from the hippocampus of WARs coupled to microarray comparative gene expression analysis, followed by Northern blot validation of individual genes. We discovered that the levels of the non-protein coding (npc) RNA BC1 were significantly reduced in the hippocampus of WARs submitted to repeated audiogenic seizures (audiogenic kindling) when compared to Wistar resistant rats and to both naive WARs and Wistars. By quantitative in situ hybridization, we verified lower levels of BC1 RNA in the GD-hilus and significant signal ratio reduction in the stratum radiatum and stratum pyramidale of hippocampal CA3 subfield of audiogenic kindled animals. Functional results recently obtained in a BC1-/- mouse model and our current data are supportive of a potential disruption in signaling pathways, upstream of BC1, associated with the seizure susceptibility of WARs. (C) 2010 Elsevier B.V. All rights reserved.

Short- and long-term anxiogenic effects induced by a single injection of subconvulsant doses of pilocarpine in rats: investigation of the putative role of hippocampal pathways

Behavioral consequences of convulsive episodes are well documented, but less attention was paid to changes that occur in response to subconvulsant doses of drugs. We investigated short- and long-term effects of a single systemic injection of a subconvulsant dose of pilocarpine on the behavior of rats as evaluated in the elevated plus maze. Pilocarpine induced an anxiogenic-like profile 24 h later, and this effect persisted for up to 3 months (% of time spent on open arms at 24 h, control = 35.47 +/- 3.23; pilocarpine 150 = 8.2 +/- 2.6; 3 months, control = 31.9 +/- 5.5; pilocarpine 150 = 9.3 +/- 4.9). Temporary inactivation of fimbria-fornix with lidocaine 4% promoted an anxiolytic-like effect per se, suggesting a tonic control of this pathway on the modulation of anxiety-related behaviors. Lidocaine also reduced the anxiogenic-like profile of animals tested 1 month after pilocarpine treatment (% of time spent on open arms, saline + phosphate-buffered saline (PBS) = 31.7 + 3.7; saline + lidocaine = 54.4 + 4.7; pilocarpine + PBS = 10.3 + 4.1; pilocarpine + lidocaine = 40.1 + 9.1). To determine whether the anxiogenic-like effect was mediated by septal region or by direct hippocampal projections to the diencephalon, the neural transmission of post-commissural fornix was blocked, and a similar reduction in the anxiogenic-like effect of pilocarpine was observed. Our findings suggest that a single systemic injection of pilocarpine may induce long-lasting anxiogenic-like behavior in rats, an effect that appears to be mediated, in part, through a direct path from hippocampus to medial hypothalamic sites involved in fear responses.

Increased Expression of GluR2-flip in the Hippocampus of the Wistar Audiogenic Rat Strain After Acute and Kindled Seizures

The Wistar Audiogenic Rat (WAR) is an epileptic-prone strain developed by genetic selection from a Wistar progenitor based on the pattern of behavioral response to sound stimulation. Chronic acoustic stimulation protocols of WARs (audiogenic kindling) generate limbic epileptogenesis, confirmed by ictal semiology, amygdale, and hippocampal EEG, accompanied by hippocampal and amygdala cell loss, as well as neurogenesis in the dentate gyrus (DG). In an effort to identify genes involved in molecular mechanisms underlying epileptic process, we used suppression-subtractive hybridization to construct normalized cDNA library enriched for transcripts expressed in the hippocampus of WARs. The most represented gene among the 133 clones sequenced was the ionotropic glutamate receptor subunit II (GluR2), a member of the a-amino-3-hydroxy-5-methyl-4-isoxazoleopropionic acid (AMPA) receptor. Although semiquantitative RT-PCR analysis shows that the hippocampal levels of the GluR2 subunits do not differ between naive WARs and their Wistar counterparts, we observed that the expression of the transcript encoding the splice-variant GluR2-flip is increased in the hippocampus of WARs submitted to both acute and kindled audiogenic seizures. Moreover, using in situ hybridization, we verified upregulation of GluR2-flip mainly in the CA1 region, among the hippocampal subfields of audiogenic kindled WARs. Our findings on differential upregulation of GluR2-flip isoform in the hippocampus of WARs displaying audiogenic seizures is original and agree with and extend previous immunohistochemical for GluR2 data obtained in the Chinese P77PMC audiogenic rat strain, reinforcing the association of limbic AMPA alterations with epileptic seizures. (C) 2009 Wiley-Liss, Inc.

Expression Profile and Distribution of Efhc1 Gene Transcript During Rodent Brain Development

One of the putative causative genes for juvenile myoclonic epilepsy (JME) is EFHC1. We report here the expression profile and distribution of Efhc1 messenger RNA (mRNA) during mouse and rat brain development. Real-time polymerase chain reaction revealed that there is no difference in the expression of Efhc1 mRNA between right and left hemispheres in both species. In addition, the highest levels of Efhc1 mRNA were found at intra-uterine stages in mouse and in adulthood in rat. In common, there was a progressive decrease in Efhc1 expression from 1-day-old neonates to 14-day-old animals in both species. In situ hybridization studies showed that rat and mouse Efhc1 mRNAs are expressed in ependymal cells of ventricle walls. Our findings suggest that Efhc1 expression is more important during initial phases of brain development and that at this stage it could be involved in key developmental mechanisms underlying JME.

Effects of voluntary running on spatial memory and mature brain-derived neurotrophic factor expression in mice hippocampus after status epilepticus

Voluntary physical activity improves memory and learning ability in rodents, whereas status epilepticus has been associated with memory impairment. Physical activity and seizures have been associated with enhanced hippocampal expression of BDNF, indicating that this protein may have a dual role in epilepsy. The influence of voluntary physical activity on memory and BDNF expression has been poorly studied in experimental models of epilepsy. In this paper, we have investigated the effect of voluntary physical activity on memory and BDNF expression in mice with pilocarpine-incluced epilepsy. Male Swiss mice were assigned to four experimental groups: pilocarpine sedentary (PS), pilocarpine runners (PRs), saline sedentary (SS) and saline runners (SRs). Two days after pilocarpine-induced status epilepticus, the affected mice (PR) and their running controls (SR) were housed with access to a running wheel for 28 days. After that, the spatial memory and the expression of the precursor and mature forms of hippocampal BDNF were assessed. PR mice performed better than PS mice in the water maze test. In addition, PR mice had a higher amount of mature BDNF (14 kDa) relative to the total BDNF (14 kDa + 28 kDa + 32 kDa forms) content when compared with PS mice. These results show that voluntary physical activity improved the spatial memory and increased the hippocampal content of mature BDNF of mice with pilocarpine-induced status epilepticus. (C) 2009 Elsevier B.V. All rights reserved.