Virus-Induced Epilepsy vs. Epilepsy Patients Acquiring Viral Infection: Unravelling the Complex Relationship for Precision Treatment

The intricate relationship between viruses and epilepsy involves a bidirectional interaction. Certain viruses can induce epilepsy by infecting the brain, leading to inflammation, damage, or abnormal electrical activity. Conversely, epilepsy patients may be more susceptible to viral infections due to factors, such as compromised immune systems, anticonvulsant drugs, or surgical interventions. Neuroinflammation, a common factor in both scenarios, exhibits onset, duration, intensity, and consequence variations. It can modulate epileptogenesis, increase seizure susceptibility, and impact anticonvulsant drug pharmacokinetics, immune system function, and brain physiology. Viral infections significantly impact the clinical management of epilepsy patients, necessitating a multidisciplinary approach encompassing diagnosis, prevention, and treatment of both conditions. We delved into the dual dynamics of viruses inducing epilepsy and epilepsy patients acquiring viruses, examining the unique features of each case. For virus-induced epilepsy, we specify virus types, elucidate mechanisms of epilepsy induction, emphasize neuroinflammation's impact, and analyze its effects on anticonvulsant drug pharmacokinetics. Conversely, in epilepsy patients acquiring viruses, we detail the acquired virus, its interaction with existing epilepsy, neuroinflammation effects, and changes in anticonvulsant drug pharmacokinetics. Understanding this interplay advances precision therapies for epilepsy during viral infections, providing mechanistic insights, identifying biomarkers and therapeutic targets, and supporting optimized dosing regimens. However, further studies are crucial to validate tools, discover new biomarkers and therapeutic targets, and evaluate targeted therapy safety and efficacy in diverse epilepsy and viral infection scenarios.

Toward the use of novel alternative methods in epilepsy modeling and drug discovery

Epilepsy is a chronic brain disease and, considering the amount of people affected of all ages worldwide, one of the most common neurological disorders. Over 20 novel antiseizure medications (ASMs) have been released since 1993, yet despite substantial advancements in our understanding of the molecular mechanisms behind epileptogenesis, over one-third of patients continue to be resistant to available therapies. This is partially explained by the fact that the majority of existing medicines only address seizure suppression rather than underlying processes. Understanding the origin of this neurological illness requires conducting human neurological and genetic studies. However, the limitation of sample sizes, ethical concerns, and the requirement for appropriate controls (many patients have already had anti-epileptic medication exposure) in human clinical trials underscore the requirement for supplemental models. So far, mammalian models of epilepsy have helped to shed light on the underlying causes of the condition, but the high costs related to breeding of the animals, low throughput, and regulatory restrictions on their research limit their usefulness in drug screening. Here, we present an overview of the state of art in epilepsy modeling describing gold standard animal models used up to date and review the possible alternatives for this research field. Our focus will be mainly on ex vivo, in vitro, and in vivo larval zebrafish models contributing to the 3R in epilepsy modeling and drug screening. We provide a description of pharmacological and genetic methods currently available but also on the possibilities offered by the continued development in gene editing methodologies, especially CRISPR/Cas9-based, for high-throughput disease modeling and anti-epileptic drugs testing.

Epilepsy following herpes simplex encephalitis - A case series

BACKGROUND

Herpes simplex encephalitis (HSE) is associated with severe mortality and morbidity. Its incidence is estimated at 1:250 000, and the typical symptomatology of acute disease including headaches, mental state disturbances, confusion, sleepiness, and seizures. The chronic phase of the disease is occasionally characterized by epilepsy and neurological deficits.

STUDY RATIONALE

The present retrospective single-center study aims to identify risk factors for predicting the development of epilepsy (epileptogenesis) following HSE.

METHODS

Medical records were screened for patients older than 18 years, hospitalized between January 2005 and September 2019 with a diagnosis of "encephalitis" and "herpes simplex virus, HSV" infection. HSE diagnosis was based on an analysis of the cerebrospinal fluid with positive HSV testing results.

RESULTS

Twenty-three patients fit our inclusion criteria: fever and behavioral changes, followed by seizures, were reported in 58.3 % of patients. On follow-up (59.7 ± 38.8 months), eight patients (34.8 %) developed epilepsy. Pathological imaging and EEG were correlated with acute symptomatic seizures (ASS). ASS was associated with an 8-fold risk increase to develop post-encephalitis epilepsy (PE). PE was associated with younger age but not with CSF results, imaging, or EEG.

CONCLUSION

Our retrospective single-center study on PE, following HSE, shows that younger age and ASS were associated with PE. Brain imaging, CSF analysis, and EEG were not associated with the development of epilepsy following HSE.

Multimodal Quality of Life Assessment in Post-9/11 Veterans With Epilepsy: Impact of Drug Resistance, Traumatic Brain Injury, and Comorbidity

BACKGROUND AND OBJECTIVES

Epilepsy is defined by the occurrence of multiple unprovoked seizures, but quality of life (QOL) in people with epilepsy is determined by multiple factors, in which psychiatric comorbidities play a pivotal role. Therefore, understanding the interplay between comorbidities and QOL across epilepsy phenotypes is an important step towards improved outcomes. Here, we report the impact of QOL across distinct epilepsy phenotypes in a cohort of post-9/11 veterans with high rates of traumatic brain injury (TBI).

METHODS

This observational cohort study from the Veterans Health Administration included post-9/11 Veterans with epilepsy. A process integrating an epilepsy identification algorithm, chart abstraction, and self-reported measures was used to classify patients into one of four groups: 1. Epilepsy controlled with medications, 2. Drug resistant epilepsy (DRE), 3. Post-traumatic epilepsy (PTE), or 4. Drug resistant post-traumatic epilepsy (PT-DRE). Summary scores for six QOL measures were compared across the groups, adjusting for age, sex, and number of comorbidities.

RESULTS

A total of 529 survey respondents with epilepsy were included in the analysis: 249 controls (i.e., epilepsy without DRE or PTE), 124 with DRE, 86 with PTE, and 70 with PT-DRE. Drug resistant epilepsy was more common in those with PTE compared with non-traumatic epilepsy (45% vs. 33%, odds ratio 1.6 (95% CI: [1.1-2.4], p=0.01)). Patients with PTE and PT-DRE had significantly more comorbid conditions in health records than those with nontraumatic epilepsy. Those with both PTE and DRE reported the lowest QOL across all six measures, and this persisted after adjustment for comorbidities, and in further linear analyses.

DISCUSSION

Among those with PTE, DRE prevalence was significantly higher than for non-traumatic epilepsies. PTE was also associated with higher burden of comorbidity, and worse overall QOL compared to those with non-traumatic epilepsies. People with PTE are distinctly vulnerable to the comorbidities associated with TBI and epilepsy. This at-risk group should be the focus of future studies aimed at elucidating the factors associated with adverse health outcomes and developing anti-epileptogenic therapies.

The Endocannabinoid System in Glial Cells and Their Profitable Interactions to Treat Epilepsy: Evidence from Animal Models

Epilepsy is one of the most common neurological conditions. Yearly, five million people are diagnosed with epileptic-related disorders. The neuroprotective and therapeutic effect of (endo)cannabinoid compounds has been extensively investigated in several models of epilepsy. Therefore, the study of specific cell-type-dependent mechanisms underlying cannabinoid effects is crucial to understanding epileptic disorders. It is estimated that about 100 billion neurons and a roughly equal number of glial cells co-exist in the human brain. The glial population is in charge of neuronal viability, and therefore, their participation in brain pathophysiology is crucial. Furthermore, glial malfunctioning occurs in a wide range of neurological disorders. However, little is known about the impact of the endocannabinoid system (ECS) regulation over glial cells, even less in pathological conditions such as epilepsy. In this review, we aim to compile the existing knowledge on the role of the ECS in different cell types, with a particular emphasis on glial cells and their impact on epilepsy. Thus, we propose that glial cells could be a novel target for cannabinoid agents for treating the etiology of epilepsy and managing seizure-like disorders.

Astrocytes Exhibit a Protective Role in Neuronal Firing Patterns under Chemically Induced Seizures in Neuron-Astrocyte Co-Cultures

Astrocytes and neurons respond to each other by releasing transmitters, such as γ-aminobutyric acid (GABA) and glutamate, that modulate the synaptic transmission and electrochemical behavior of both cell types. Astrocytes also maintain neuronal homeostasis by clearing neurotransmitters from the extracellular space. These astrocytic actions are altered in diseases involving malfunction of neurons, e.g., in epilepsy, Alzheimer's disease, and Parkinson's disease. Convulsant drugs such as 4-aminopyridine (4-AP) and gabazine are commonly used to study epilepsy in vitro. In this study, we aim to assess the modulatory roles of astrocytes during epileptic-like conditions and in compensating drug-elicited hyperactivity. We plated rat cortical neurons and astrocytes with different ratios on microelectrode arrays, induced seizures with 4-AP and gabazine, and recorded the evoked neuronal activity. Our results indicated that astrocytes effectively counteracted the effect of 4-AP during stimulation. Gabazine, instead, induced neuronal hyperactivity and synchronicity in all cultures. Furthermore, our results showed that the response time to the drugs increased with an increasing number of astrocytes in the co-cultures. To the best of our knowledge, our study is the first that shows the critical modulatory role of astrocytes in 4-AP and gabazine-induced discharges and highlights the importance of considering different proportions of cells in the cultures.

Predictors of Seizure Freedom in Patients Undergoing Surgery for Central Nervous System Infection-Related Epilepsy: A Systematic Review and Meta-Analysis

Objective: Central nervous system infections (CNSIs), especially viral encephalitis and meningitis, are well-recognized causes of medically refractory epilepsy. Although surgery is an effective and durable intervention against these infections, the seizure control outcomes described in previous surgical series have been variable. Accordingly, it is not clear which variables are most valuable in predicting seizure control following surgery for CNSI. The aim of this meta-analysis was to identify the predictors of favorable surgical outcomes in CNSI-related epilepsy.

Methods: The PubMed, EMBASE, Cochrane Library, WANGFANG, VIP, CBM, and CNKI databases were searched for studies according to the inclusion criteria. Prognostic factors, surgical outcomes, and patient characteristics were extracted. Heterogeneity was detected by the I² and Q statistics.

Results: Seventeen studies were included in our meta-analysis. Eight predictors of favorable outcomes (Engel Class I/II) were determined, including abnormal MRI findings, meningitis, temporal location only, regional ictal pattern, unilateral ictal pattern, older age at epilepsy, longer silent period, and longer time from infection, as follows: OR = 3.34 (95% CI 1.44–7.74), OR = 0.31 (95% CI 0.13–0.70), OR = 0.34 (95% CI 0.16–0.74), OR = 5.65 (95% CI 1.75–18.30), and OR = 9.53 (95% CI 2.36–38.48), respectively, and MD = 2.15 (95% CI 0.20–4.11), MD = 2.40 (95% CI 0.09–4.70), and MD = 8.49 (95% CI 1.50–15.48), respectively. A subgroup analysis found the following associations: regional and unilateral ictal patterns in viral encephalitis, a younger age at infection in parasitic encephalopathy, an older age at surgery, a longer time from onset, and a longer time from infection in unexplained meningitis. A sensitivity analysis restricted to studies that included each variable yielded robust results. Little evidence of publication bias was observed.

Conclusions: This meta-analysis suggests that abnormal MRI findings, meningitis, temporal location only, regional and unilateral ictal patterns, older age at epilepsy, longer silent period, and longer time from infection are predictive factors in patients with favorable surgical outcomes in CNSI-related epilepsy. In addition, different infective agents influenced the results in regional and unilateral ictal patterns in ictal electroencephalography, as well as the relationship between age at infection and surgery and the time from epilepsy onset and infection.

Application of Thermodynamics and Protein–Protein Interaction Network Topology for Discovery of Potential New Treatments for Temporal Lobe Epilepsy

In this paper, we propose a bioinformatics-based method, which introduces thermodynamic measures and topological characteristics aimed to identify potential drug targets for pharmaco-resistant epileptic patients. We apply the Gibbs homology analysis to the protein–protein interaction network characteristic of temporal lobe epilepsy. With the identification of key proteins involved in the disease, particularly a number of ribosomal proteins, an assessment of their inhibitors is the next logical step. The results of our work offer a direction for future development of prospective therapeutic solutions for epilepsy patients, especially those who are not responding to the current standard of care.

UNC13B variants associated with partial epilepsy with favourable outcome

The unc-13 homolog B (UNC13B) gene encodes a presynaptic protein, mammalian uncoordinated 13-2 (Munc13-2), that is highly expressed in the brain-predominantly in the cerebral cortex-and plays an essential role in synaptic vesicle priming and fusion, potentially affecting neuronal excitability. However, the functional significance of UNC13B mutation in human disease is not known. In this study we screened for novel genetic variants in a cohort of 446 unrelated cases (families) with partial epilepsy without acquired causes by trio-based whole-exome sequencing. UNC13B variants were identified in 12 individuals affected by partial epilepsy and/or febrile seizures from eight unrelated families. The eight probands all had focal seizures and focal discharges in EEG recordings, including two patients who experienced frequent daily seizures and one who showed abnormalities in the hippocampus by brain MRI; however, all of the patients showed favorable outcome without intellectual or developmental abnormalities. The identified UNC13B variants included one nonsense variant, two variants at or around a splice site, one compound heterozygous missense variant, and four missense variants that cosegregated in the families. The frequency of UNC13B variants identified in the present study was significantly higher than that in a control cohort of Han Chinese and controls of the East Asian and all populations in the Genome Aggregation Database. Computational modeling, including hydrogen bond and docking analyses, suggested that the variants lead to functional impairment. In Drosophila, seizure rate and duration were increased by Unc13b knockdown compared to wild-type flies, but these effects were less pronounced than in sodium voltage-gated channel alpha subunit 1 (Scn1a) knockdown Drosophila. Electrophysiologic recordings showed that excitatory neurons in Unc13b-deficient flies exhibited increased excitability. These results suggest that UNC13B is potentially associated with epilepsy. The frequent daily seizures and hippocampal abnormalities but ultimately favorable outcome under antiepileptic therapy in our patients indicate that partial epilepsy caused by UNC13B variant is a clinically manageable condition.

The study of ischemia modified albumin as an early biomarker of epilepsy in adolescent population: a cross-sectional study

OBJECTIVES

Epilepsy is one of the most common neurological disorders, diagnosis of which is challenging as many unrelated conditions may mimic seizure. Epilepsy impairs the quality of life of patients due to associated physical and psychological trauma. Epileptic patients are also at increased risk of premature death due to autonomic disturbance and fatal accidents. The aim of the present research work was to study ischemia modified albumin (IMA) as an early biomarker of epilepsy in the adolescent population.

METHODS

Twenty-five diagnosed cases of epilepsy and 25 healthy volunteers as control of adolescent group were recruited as study subjects. The study subjects were age and sex matched. Clinical evaluation, routine biochemical parameters and IMA estimation were carried out. Serum IMA was measured by spectrophotometric method.

RESULTS

The mean serum IMA levels were significantly raised in epileptic patients (0.69 ± 0.1 absorbance units [ABSU]) as compared to the healthy control group (0.52 ± 0.24 ABSU) (p=0.004). ROC curve of IMA predicted that at cut off of 0.59 ABSU, the IMA has 96% sensitivity and 52% specificity for diagnosing epilepsy.

CONCLUSIONS

IMA may be used as a biomarker for early diagnosis of epilepsy as well as to differentiate epileptic seizure from various non epileptic disorders in the adolescent population.

Genetic Interaction of H19 and TGFBR1 Polymorphisms with Risk of Epilepsy in a Chinese Population

PURPOSE

Long non-coding RNA H19 was highly expressed in the latent period of epilepsy, contributing to apoptosis of hippocampal neurons by targeting let-7b. Transforming growth factor beta receptor 1 (TGFBR1), a target of let-7b, is located on the susceptibility locus for epilepsy. In this context, we investigated the association between tagSNPs in long non-coding RNA H19 and transforming growth factor beta receptor 1 (TGFBR1) rs6478974 and the risk of epilepsy.

PATIENTS AND METHODS

The present study consisted of 302 patients with epilepsy and 612 age- and gender-matched controls. The polymorphisms were analyzed using a TaqMan allelic genotyping assay. H19 and TGFBR1 mRNA levels were determined using quantitative real-time polymerase chain reaction.

RESULTS

The TGFBR1 AT and TT genotypes emerged as a protective factor for the risk of epilepsy (AT vs AA: adjusted OR = 0.59, 95% CI: 0.39-0.89, P = 0.01; TT vs AA: adjusted OR = 0.53, 95% CI: 0.35-0.80, P = 0.002, respectively). The protective effect was also observed in recessive genetic model (adjusted OR = 0.56, 95% CI: 0.38-0.82, P = 0.003). Individuals carrying the rs6478974 TT genotype had lower levels of TGFBR1 mRNA. Moreover, the TCTAT and TCCAA haplotypes emerged as a risk factor for epilepsy and the rs3741219-rs2839698-rs6478974 was associated with an interactive effect on the risk of epilepsy.

CONCLUSION

The current study provides evidence of the rs6478974 TT genotype decreasing the susceptibility to epilepsy by reducing the levels of TGFBR1 mRNA.

Antiepileptic drugs for acute encephalitic patients presented with seizure

OBJECTIVE

The aim of this study was to clarify the pattern and efficacy of antiepileptic drugs (AEDs) in acute encephalitis and discuss how long AEDs should be used after the acute phase.

METHODS

Patients with acute encephalitis who presented with seizure were enrolled. The clinical features were systematically gathered, and the information about AEDs and seizures was obtained by a clinical follow-up and (or) a telephone interview based on a structured form.

RESULTS

A total of 327 patients were enrolled, and the mean follow-up period was 63.8 (14-123) months. The risk of seizure relapse was estimated as 43.6% five years after the acute phase and the first three months was the peak time for relapse. Univariate analysis showed that status epilepticus, more than one seizure, cerebral spinal fluid protein level, abnormal MRI finding, temporal lobe involvement, and epileptiform discharge were related to seizure relapse. But only more than one seizure (OR = 2.80 (95% CI 1.29-6.09), p = 0.009) and temporal lobe involvement (5.34 (2.68-10.64), p < 0.001) remain predictive on multivariate regression analysis. For patients with only one seizure and no temporal lobe involvement, the risk of seizure relapse was similar between those with or without AED (2/29 vs. 4/28, p = 0.423). For the rest, the risks of relapse were similar among those who took sodium valproate and levetiracetam.

SIGNIFICANCE

For patients with only one seizure and no temporal lobe involvement, AEDs may not be strictly needed. The first three months after acute phase was the peak time for relapse and AEDs may should be used during this period. Both sodium valproate and levetiracetam could be selected.

Neuroinflammation in Post-Traumatic Epilepsy: Pathophysiology and Tractable Therapeutic Targets

Epilepsy is a common chronic consequence of traumatic brain injury (TBI), contributing to increased morbidity and mortality for survivors. As post-traumatic epilepsy (PTE) is drug-resistant in at least one-third of patients, there is a clear need for novel therapeutic strategies to prevent epilepsy from developing after TBI, or to mitigate its severity. It has long been recognized that seizure activity is associated with a local immune response, characterized by the activation of microglia and astrocytes and the release of a plethora of pro-inflammatory cytokines and chemokines. More recently, increasing evidence also supports a causal role for neuroinflammation in seizure induction and propagation, acting both directly and indirectly on neurons to promote regional hyperexcitability. In this narrative review, we focus on key aspects of the neuroinflammatory response that have been implicated in epilepsy, with a particular focus on PTE. The contributions of glial cells, blood-derived leukocytes, and the blood–brain barrier will be explored, as well as pro- and anti-inflammatory mediators. While the neuroinflammatory response to TBI appears to be largely pro-epileptogenic, further research is needed to clearly demonstrate causal relationships. This research has the potential to unveil new drug targets for PTE, and identify immune-based biomarkers for improved epilepsy prediction.

Chronic post-encephalitic epilepsy following Japanese encephalitis: Clinical features, neuroimaging data, and outcomes

PURPOSE

Japanese encephalitis (JE), the main cause of viral encephalitis in Asia, usually presents with acute symptomatic seizures; however, there have been very few systematic reports regarding late unprovoked seizures and epilepsy. We aimed to describe the clinical features and outcomes of post-encephalitic epilepsy following JE.

METHODS

Patients with epilepsy with a previous confirmed diagnosis of JE visiting West China Hospital from 2013 to 2019 were enrolled in the observational case-controlled study. Patients with epilepsy with a history of other non-specific viral encephalitis were enrolled as controls. For all enrolled subjects, disease related information was recorded.

RESULTS

Forty-eight patients with JE (20 males; median age, 21.0 years; average epilepsy duration, 8.55 years) were identified. The median duration from JE to the first unprovoked seizure was 7.73 years, which significantly differed from that of the controls (7.73 vs. 2.69 years, respectively; p = 4.59 × 10^-6). Most patients had focal epilepsy, and 29 (78.38%) were drug resistant. Among 45 patients with available neuroimaging data, three in fourth had no obvious abnormality, and the temporal lobe and hippocampus (22.22%) were the most affected brain regions. Six patients had surgery, and three achieved class-one seizure-free status.

CONCLUSION

The latency to the first unprovoked seizure was longer in patients with JE than controls. Regarding chronic epilepsy, three in four had structural abnormalities, and the long-term outcomes of post-encephalitic epilepsy following JE were poor. Surgery remains an option for drug-resistant epilepsy.

In Vitro Models of Brain Disorders

The brain is the most complex organ of the body, and many pathological processes underlying various brain disorders are poorly understood. Limited accessibility hinders observation of such processes in the in vivo brain, and experimental freedom is often insufficient to enable informative manipulations. In vitro preparations (brain slices or cultures of dissociated neurons) offer much better accessibility and reduced complexity and have yielded valuable new insights into various brain disorders. Both types of preparations have their advantages and limitations with regard to lifespan, preservation of in vivo brain structure, composition of cell types, and the link to behavioral outcome is often unclear in in vitro models. While these limitations hamper general usage of in vitro preparations to study, e.g., brain development, in vitro preparations are very useful to study neuronal and synaptic functioning under pathologic conditions. This chapter addresses several brain disorders, focusing on neuronal and synaptic functioning, as well as network aspects. Recent progress in the fields of brain circulation disorders, excitability disorders, and memory disorders will be discussed, as well as limitations of current in vitro models.

Nationwide analysis of unplanned 30-day readmissions after transsphenoidal pituitary surgery

BACKGROUND

Transsphenoidal pituitary surgery has evolved into a safe procedure with shorter hospitalizations, yet unplanned readmissions remain a quality measure for which there is a paucity of data. We sought to examine rates, timing, etiologic factors, and costs surrounding readmission after transsphenoidal pituitary surgery.

METHODS

The Nationwide Readmissions Database (NRD) was queried for patients who underwent transsphenoidal pituitary between January 2013 and November 2013. Patient, procedure, admission, and hospital-level characteristics were compared for patients with and without unplanned 30-day readmission. Multivariate logistic regression was used to identify readmission predictors. A total of 8546 patients were included in this retrospective study.

RESULTS

A total of 8546 patients with a median age of 54 years and female predominance were identified, with 742 patients experiencing at least 1 unplanned readmission within 30 days of index admission. Hypertension, hypothyroidism, diabetes, and obesity were common comorbidities among readmitted patients. Readmission was most frequently because of nervous system complications, followed by neurohypophyseal or electrolyte disorders, cerebrospinal fluid leak, hemorrhage, and meningitis. Median length and cost of stay of index admission was greater in the readmission group (p < 0.001). Fluid and electrolyte disorders as well as neurologic disease (most commonly epilepsy or convulsions) present on initial admission were predictive of length of initial stay and readmission (p < 0.001). Median readmission cost was $7723 and was expected to occur within 7 days.

CONCLUSION

Approximately 8.7% of patients undergoing transsphenoidal pituitary surgery experience an unplanned readmission within 30 days of discharge. Risk factors identified should be considered to reduce preventable readmissions and identify medically complex patients.

Epidemiology of neurocysticercosis and epilepsy, is everything described?

In recent years clinical and epidemiological research on cysticercosis has gained significant interest in some countries, especially in Latin American countries and some countries in Asia and Africa. For many years it has been proposed that the higher prevalence of epilepsy seen in some regions such as Latin-America could be explained by parasitic infections, particularly neurocysticercosis (NCC). In this review we discussed selected epidemiological topics of the association of NCC and epilepsy, such as global distribution around the world, identification of NCC in developed countries, drug resistant epilepsy and NCC. Finally this review presents a critical review of biases of the published literature in NCC. This article is part of a Special Issue entitled "Neurocysticercosis and Epilepsy".

Integrated network analysis reveals potentially novel molecular mechanisms and therapeutic targets of refractory epilepsies

Epilepsy is a complex neurological disorder and a significant health problem. The pathogenesis of epilepsy remains obscure in a significant number of patients and the current treatment options are not adequate in about a third of individuals which were known as refractory epilepsies (RE). Network medicine provides an effective approach for studying the molecular mechanisms underlying complex diseases. Here we integrated 1876 disease-gene associations of RE and located those genes to human protein-protein interaction (PPI) network to obtain 42 significant RE-associated disease modules. The functional analysis of these disease modules showed novel molecular pathological mechanisms of RE, such as the novel enriched pathways (e.g., "presynaptic nicotinic acetylcholine receptors", "signaling by insulin receptor"). Further analysis on the relationships between current drug targets and the RE-related disease genes showed the rational mechanisms of most antiepileptic drugs. In addition, we detected ten potential novel drug targets (e.g., KCNA1, KCNA4-6, KCNC3, KCND2, KCNMA1, CAMK2G, CACNB4 and GRM1) located in three RE related disease modules, which might provide novel insights into the new drug discovery for RE therapy.

Neural plasticity and network remodeling: From concepts to pathology

Neuroplasticity has been subject to a great deal of research in the last century. Recently, significant emphasis has been placed on the global effect of localized plastic changes throughout the central nervous system, and on how these changes integrate in a pathological context. Specifically, alterations of network functionality have been described in various pathological contexts to which corresponding structural alterations have been proposed. However, considering the amount of literature and the different pathological contexts, an integration of this information is still lacking. In this paper we will review the concepts of neural plasticity as well as their repercussions on network remodeling and provide a possible explanation to how these two concepts relate to each other. We will further examine how alterations in different pathological contexts may relate to each other and will discuss the concept of plasticity diseases, its models and implications.

The relationship of cortical folding and brain arteriovenous malformations

Background

The pathogenesis of human intracranial arteriovenous malformations (AVMs) is not well understood; this study aims to quantitatively assess cortical folding in patients with these lesions.

Methods

Seven adult participants, 4 male and 3 female, with unruptured, surgically unresectable intracranial AVMs were prospectively enrolled in the study, with a mean age of 42.1 years and Spetzler-Martin grade range of II–IV. High-resolution brain MRI T1 and T2 sequences were obtained. After standard preprocessing, segmentation and registration techniques, three measures of cortical folding, the depth difference index (DDI), coordinate distance index (CDI) and gyrification index (GI)), were calculated for the affected and unaffected hemispheres of each subject as well as a healthy control subject set.

Results

Of the three metrics, CDI, DDI and GI, used for cortical folding assessment, none demonstrated significant differences between the participants and previously studied healthy adults. There was a significant negative correlation between the DDI ratio between affected and unaffected hemispheres and AVM volume (correlation coefficient r = −0.74, p = 0.04).

Conclusion

This study is the first to quantitatively assess human brain cortical folding in the presence of intracranial AVMs and no significant differences between AVM-affected versus unaffected hemispheres were found in a small dataset. We suggest longitudinal, larger human MRI-based cortical folding studies to assess whether AVMs are congenital lesions of vascular development or de novo, dynamic lesions.

Neonatal hyperbilirubinemia and the risk of febrile seizures and childhood epilepsy

PURPOSE

The aim of the study was to estimate the association between newborn children treated with phototerapy for hyperbilirubinemia and the subsequent risk of febrile seizures or epilepsy in early childhood.

METHODS

We conducted a follow-up study of singleton children (N=70 230) born between February 1998 and May 2003 from the Danish National Birth Cohort (DNBC). Information on exposure to phototherapy for hyperbilirubinemia was obtained from a questionnaire in the DNBC. Information on epilepsy and febrile seizures were obtained from the Danish National Hospital Registry (DNHR). Cox proportional hazard regression model was used to calculate hazard ratios (HRs) with 95% confidence intervals (CI).

RESULTS

Newborns treated with phototherapy for hyperbilirubinemia had a higher risk of developing epilepsy in early childhood (HR: 1.66, 95% CI: 1.23-2.24) but not febrile seizures (HR: 1.04, 95% CI: 0.86-1.27). The increases risk of epilepsy were only present for boys (HR: 1.98, 95% CI: 1.40-2.78) not for girls (HR: 1.14, 95% CI: 0.64-2.02) CONCLUSION: Phototherapy for hyperbilirubinemia in newborns was associated with an increased risk of epilepsy for males in early childhood. No excess risk was seen with febrile seizures.

Association of Nicotinamide-N-Methyltransferase Gene rs694539 Variant with Epilepsy

Here, we report the association of the rs694539 variant of nicotinamide-N-methyltransferase gene with epilepsy in a case-control study of 215 patients with epilepsy and 239 healthy controls (χ (2) = 11.641, P = 0.003). The individuals with the GG genotype revealed protection against epilepsy (χ (2) = 5.866, P = 0.015, OR = 0.623, 95 % CI = 0.425-0.915), whereas the individuals with the AA genotype showed statistically significant increased risk for epilepsy (χ (2) = 8.676, P = 0.003, OR = 5.479, 95 % CI = 1.553-19.337). In addition, the G allele was protective against epilepsy (χ (2) = 8.676, P = 0.003, OR = 0.183, 95 % CI = 0.052-0.644); on the contrary, the A allele was a genetic risk factor for epilepsy (χ (2) = 5.866, P = 0.015, OR = 1.604, 95 % CI = 1.093-2.354). Stratification analysis revealed that the association was statistically significant in male patients with epilepsy (χ (2) = 6.682, P = 0.035). However, the statistical power was only 0.33 in female patients with epilepsy (χ (2) = 5.275, P = 0.072). This finding, for the first time, suggests the involvement of the NNMT gene rs694539 variant in the etiology of epilepsy.

Postencephalitic epilepsy: clinical characteristics and predictors

OBJECTIVE

To describe the etiologies, clinical presentations, outcomes, and predictors of postencephalitic epilepsy (PE) in a large series of adult patients with acute encephalitis.

METHODS

We conducted a retrospective review of patients diagnosed with acute encephalitis at Mayo Clinic, Rochester, between January 2000 and December 2012. The patients were categorized into two groups based on the presence or absence of PE at last follow-up. Multivariate logistic regression analysis was used to analyze factors associated with PE.

RESULTS

We identified 198 consecutive patients (100 [50.5%] male and 98 [49.5%] female) with a median age of 58 years (range 41.8-69). Etiologies included viral infection (n=95, 48%), autoimmune (n=44, 22%), and unknown/others (n=59, 30%). During hospitalization, seizures were seen in patients with autoimmune encephalitis (n=24, 54.5%), unknown/others (n=20, 33.9%), and viral encephalitis (n=23, 24.2%). Interictal epileptiform discharges on electroencephalography (EEG) were present in 34 (54%), whereas periodic lateralized epileptiform discharges (PLEDs) and generalized periodic discharges (GPDs) were seen in 14 (41.2%) and 2 (5.9%) patients. Forty-six patients with seizures (70.8%) had fluid-attenuated inversion recovery (FLAIR)/T2 abnormalities, 20 (31.3%) diffusion abnormalities, and 43 (66.2%) cortical involvement. Good outcome at discharge among patients with seizures was seen in 8/23 patients with viral etiology (34.8%), 10/24 patients with autoimmune encephalitis (45.5%), and 12/20 patients with unknown cause (60%). PE was present in 43 patients (29.9%). On multivariate regression analysis, the factors associated with PE were generalized seizures during hospitalization (p=0.03), focal seizures (p≤0.001), and the presence of FLAIR/T2 abnormalities on brain magnetic resonance imaging (MRI) (p=0.003).

SIGNIFICANCE

The presence of seizures during hospitalization and an abnormal brain MRI are the strongest predictors of the development of PE. The etiology of encephalitis, presence of focal neurologic deficits, and interictal EEG abnormalities did not influence the development of PE.

Epilepsy: Asia versus Africa

Is epilepsy truly an "African ailment"? We aimed to determine this, since international health agencies often refer to epilepsy as an African disease and the scientific literature has spoken the same tone. Various published materials, mainly reports, articles, were used to gather Asian and African evidence on various aspects of epilepsy and many of its risk and associated factors. Our results suggest that in no way can epilepsy be considered as an African ailment and such characterization is most likely based on popular beliefs rather than scientific evidence. In comparison to Africa, Asia has a 5.0% greater burden from all diseases, and is 17.0% more affected from neuropsychiatric disorders (that include epilepsy). Given that more countries in Asia are transitioning, there may be large demographic and lifestyle changes in the near future. However these changes are nowhere close to those expected in Africa. Moreover, 23 million Asians have epilepsy in comparison to 3.3 million Africans and 1.2 million sub-Saharan Africans. In comparison to Africa, Asia has more untreated patients, 55.0% more additional epilepsy cases every year, because of its larger population, with greater treatment cost and possibly higher premature mortality. Of several associated factors discussed herein, many have more importance for Asia than Africa. The current state of epilepsy in Asia is far less than ideal and there is an urgent need to recognize and accept the importance of epilepsy in Asia. In no way can epilepsy be considered as an African ailment. This is most likely based on popular beliefs rather than scientific evidence. A PowerPoint slide summarizing this article is available for download in the Supporting Information section here.

Neuroimaging of epilepsy: a review of MRI findings in uncommon etiologies and atypical presentations of seizures

ABSTRACT: 

Imaging patients with seizures presents a challenge to both clinician and radiologist, especially when symptoms or EEG features are atypical, not conforming to established epilepsy syndromes or EEG patterns. Appropriate, directed use of MRI enhances the detection of underlying epileptogenic foci and can evaluate both common and unusual etiologies. This review examines imaging evaluation of epilepsies due to uncommon presentations of common conditions, unusual conditions and atypical seizure presentations. Understanding these uncommon presentations of seizures ensures optimal clinical management and can guide appropriate intervention. Advances in newer imaging methods including diffusion tensor imaging, functional connectivity MRI, magnetic source imaging and magnetic resonance spectroscopic imaging can further increase sensitivity to detect subtle structural abnormalities causing epilepsy and can also be used to plan more successful epilepsy surgery.

Epilepsy treatment by sacrificing vitamin D

Epilepsy is one of the most common neurologic disorders in childhood that often requires long term treatment with antiepileptic drugs. Both antiepileptic treatment and the comorbidities associated with epilepsy have a negative impact on bone health in growing children. Given the fact that vitamin D deficiency is a major public health problem worldwide, clinicians caring for children with chronic diseases should be aware of effects of the medication on the bone metabolism. Yet, vitamin D deficiency due to antiepileptic treatment is an overlooked issue among neurologists. In this review, we briefly describe vitamin D metabolism and the effect of vitamin D in the brain. We also discuss the literature in terms of vitamin D deficiency and antiepileptic treatment in the pediatric population.

Association between methylenetetrahydrofolate reductase C677T polymorphism and epilepsy susceptibility: a meta-analysis

PURPOSE

Methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism has been implicated as a potential risk factor for epilepsy. To date, many case-control studies have investigated the association between MTHFR C677T polymorphism and epilepsy susceptibility. However, those findings were inconsistent. The objective of this study is to evaluate the precise association between MTHFR C677T polymorphism and epilepsy.

METHODS

An electronic search of PubMed, EMBASE for papers on the MTHFR C677T polymorphism and epilepsy susceptibility was performed. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the association.

RESULTS

Ten case-control studies containing 1713 cases and 1867 controls regarding MTHFR C677T polymorphism were selected. A significant association between the MTHFR C677T polymorphism and epilepsy susceptibility was revealed in this meta-analysis (for T vs. C: OR=1.19, 95% CI=1.08-1.32; for TT+CT vs. CC: OR=1.20, 95% CI=1.05-1.38; for TT vs. CC: OR=1.48, 95% CI=1.20-1.83; for TT vs. CT+CC: OR=1.35, 95% CI=1.12-1.64). In subgroup analysis by ethnicity, the results also indicated the association between the MTHFR C677T polymorphism and epilepsy susceptibility within the Asian populations (for T vs. C: OR=1.55, 95% CI=1.15-2.07; for TT+CT vs. CC: OR=1.67, 95% CI=1.08-2.59; for TT vs. CC: OR=2.33, 95% CI=1.30-4.20; for TT vs. CT+CC: OR=1.89, 95% CI=1.12-3.18).

CONCLUSION

The results indicated that MTHFR C677T polymorphism was associated with an increased risk of epilepsy. However, further studies in various regions are needed to confirm the findings from this meta-analysis.

Patient heal thyself: modeling and treating neurological disorders using patient-derived stem cells

Disorders of the brain and spinal cord are common worldwide problems but have remained very difficult to treat. As a group they have diverse etiologies and can be due to trauma, infection, tumors, genetic mutations and environmental insults. Though distinct in etiology, neurological disorders share an overall intractability as current therapies are largely limited to treatment of symptoms. Improved outcomes are further constrained by the minimal endogenous capacity of the brain and spinal cord for repair. Spectacular recent scientific advances, however, suggest that new stem cell-based approaches may change this undesirable situation. In this review, I will broadly outline the challenges of studying and treating disorders of the brain and spinal cord. I will review ongoing attempts to use stem cell-based therapies to both model and treat neurological disorders. While this field is in its infancy, expected advances and needed breakthroughs point to a future where patient-derived stem cells will be the basis for the emerging discipline of regenerative neurology.

Epilepsy in poor regions of the world

Epilepsy is a common disorder, particularly in poor areas of the world, and can have a devastating effect on people with the disorder and their families. The burden of epilepsy in low-income countries is more than twice that found in high-income countries, probably because the incidence of risk factors is higher. Many of these risk factors can be prevented with inexpensive interventions, but there are only a few studies that have assessed the effect of reducing risk factors on the burden of epilepsy. The mortality associated with epilepsy in low-income countries is substantially higher than in less impoverished countries and most deaths seem to be related to untreated epilepsy (eg, as a result of falls or status epilepticus), but the risk factors for death have not been adequately examined. Epilepsy is associated with substantial stigma in low-income countries, which acts as a barrier to patients accessing biomedical treatment and becoming integrated within society. Seizures can be controlled by inexpensive antiepileptic drugs, but the supply and quality of these drugs can be erratic in poor areas. The treatment gap for epilepsy is high (>60%) in deprived areas, but this could be reduced with low-cost interventions. The substantial burden of epilepsy in poor regions of the world can be reduced by preventing the risk factors, reducing stigma, improving access to biomedical diagnosis and treatment, and ensuring that there is a continuous supply of good quality antiepileptic drugs.