Interleukin-1beta contributes to the generation of experimental febrile seizures

Inflammatory and immune mechanisms underlying epileptogenesis and epilepsy: From pathogenesis to treatment target

Epilepsy is a brain disease associated with epileptic seizures as well as with neurobehavioral outcomes of this condition. In the last century, inflammation emerged as a crucial factor in epilepsy etiology. Various brain insults through activation of neuronal and non-neuronal brain cells initiate a series of inflammatory events. Growing observations strongly suggest that abnormal activation of critical inflammatory processes contributes to epileptogenesis, a gradual process by which a normal brain transforms into the epileptic brain. Increased knowledge of inflammatory pathways in epileptogenesis has unveiled mechanistic targets for novel antiepileptic therapies. Molecules specifically targeting the pivotal inflammatory pathways may serve as promising candidates to halt the development of epilepsy. The present paper reviews the pieces of evidence conceptually supporting the potential role of inflammatory mechanisms and the relevant blood-brain barrier (BBB) disruption in epileptogenesis. Also, it discusses the mechanisms underlying inflammation-induced neuronal-glial network impairment and highlights innovative neuroregulatory actions of typical inflammatory molecules. Finally, it presents a brief analysis of observations supporting the therapeutic role of inflammation-targeting tiny molecules in epileptic seizures.

Tumor Necrosis Factor-α, the Pathological Key to Post-Traumatic Epilepsy: A Comprehensive Systematic Review

Post-traumatic epilepsy (PTE) is one of the detrimental outcomes of traumatic brain injury (TBI), resulting in recurrent seizures that impact daily life. However, the pathological relationship between PTE and TBI remains unclear, and commonly prescribed antiepileptic drugs (AED) are ineffective against PTE. Fortunately, emerging research implicates neuroinflammation, particularly, tumor necrosis factor-α (TNF-α), as the key mediator for PTE development. Thus, this review aims to examine the available literature regarding the role of TNF-α in PTE pathology and, subsequently, evaluate TNF-α as a possible target for its treatment. A comprehensive literature search was conducted on four databases including PubMed, CINAHL, Embase, and Scopus. Articles with relevance in investigating TNF-α expression in PTE were considered in this review. Critical evaluation of four articles that met the inclusion criteria suggests a proportional relationship between TNF-α expression and seizure susceptibilit and that neutralization or suppression of TNF-α release results in reduced susceptibility to seizures. In conclusion, this review elucidates the importance of TNF-α expression in epileptogenesis postinjury and urges future research to focus more on clinical studies involving TNF-α, which may provide clearer insight into PTE prevention, therefore improving the lives of PTE patients.

Structure-based discovery of CZL80, a caspase-1 inhibitor with therapeutic potential for febrile seizures and later enhanced epileptogenic susceptibility

BACKGROUND AND PURPOSE

Febrile seizures (FS), the most common seizures in childhood and often accompanied by later epileptogenesis, are not well controlled. Inflammatory processes have been implicated in the pathophysiology of epilepsy. However, whether caspase-1 is involved in FS generation and could be a target for the treatment of FS is still unclear.

EXPERIMENTAL APPROACH

By using pharmacological and gene intervention methods in C57BL/6J mice, we assessed the role of caspase-1 in FS generation. We used structural virtual screening against the active site of caspase-1, to screen compounds for druggable and safe low MW inhibitors of caspase-1 in vitro. One compound was chosen to test in vivo for therapeutic potential, using FS models in neonatal mice and epileptogenesis in adult mice.

KEY RESULTS

In mice, levels of cleaved caspase-1 increased prior to FS onset. Caspase-1^-/- mice were resistant to FS and showed lower neuronal excitability than wild-type littermates. Conversely, overexpression of caspase-1 using in utero electroporation increased neuronal excitability and enhanced susceptibility to FS. The structural virtual screening, using molecular docking approaches for the active site of caspase-1 of over 1 million compounds yielded CZL80, a brain-penetrable, low MW inhibitor of caspase-1. In neonatal mice, CZL80 markedly reduced neuronal excitability and incidence of FS generation, and, in adult mice, relieved later enhanced epileptogenic susceptibility. CZL80 was devoid of acute diazepam-like respiratory depression and chronic liver toxicity.

CONCLUSION AND IMPLICATIONS

Caspase-1 is essential for FS generation. CZL80 is a promising low MW inhibitor of FS and later enhanced epileptogenic susceptibility.

Increased levels of NLRP3 in children with febrile seizures

OBJECTIVE

Febrile seizures (FS) are the most common convulsions in childhood. Interleukin-1beta (IL-1β) is proposed to play an important role in the development of FS, from in vitro data and data from peripheral blood samples. IL-1β secretion is needed for activation of the NLR family, pyrin-domain containing 3(NLRP3) inflammasome. However, whether NLRP3 play a role in the development of FS remains unknown. This study aimed to investigate the role of NLRP3 in FS.

METHODS

Thirty-two FS cases and twenty-two matched controls were included in this study. Control samples were collected from children with febrile illness without seizures. We detected their levels of IL-1β and NLRP3 by Enzyme linked immunosorbent assay and Western blot, respectively.

RESULTS

Serum IL-1β levels weresignificantlyhigher in FS patients (Median = 301.64 pg/ml) than in fever only controls (Median = 159.48 pg/ml) (P < 0.05). Additionally, NLRP3 protein levels of peripheral blood mononuclear cells (PBMC) were significantly higher in typical FS than in fever only controls (P < 0.05). Moreover, serum levels of IL-1β were significantly correlated with levels of NLRP3 protein (r = 0.787, P < 0.001).

CONCLUSIONS

In this study, our results firstly indicated that NLRP3 protein was significantly up-regulated in the typical FS children compared in fever only controls. Increased NLRP3 can mediate IL-1β secretion that is responsible for the occurrence of FS.

Serum α-synuclein and IL-1β are increased and correlated with measures of disease severity in children with epilepsy: potential prognostic biomarkers?

BACKGROUND

The search for noninvasive biomarkers of neuroinflammation and neurodegeneration has focused on various neurological disorders, including epilepsy. We sought to determine whether α-synuclein and cytokines are correlated with the degree of neuroinflammation and/or neurodegeneration in children with epilepsy and with acquired demyelinating disorders of the central nervous system (CNS), as a prototype of autoimmune neuroinflammatory disorders.

METHODS

We analyzed serum and exosome levels of α-synuclein and serum proinflammatory and anti-inflammatory cytokines among 115 children with epilepsy and 10 acquired demyelinating disorders of the CNS and compared to 146 controls. Patients were enrolled prospectively and blood was obtained from patients within 48 h after acute afebrile seizure attacks or relapse of neurological symptoms. Acquired demyelinating disorders of the CNS include acute disseminated encephalomyelitis, multiple sclerosis, neuromyelitis optica spectrum disorders, and transverse myelitis. The controls were healthy age-matched children. The serum exosomes were extracted with ExoQuick exosome precipitation solution. Serum α-synuclein levels and serum levels of cytokines including IFN-β, IFN-γ, IL-1β, IL-6, IL-10 and TNF-α were measured using single and multiplex ELISA kits. Data were analyzed and compared with measures of disease severity, such as age at disease onset, duration of disease, and numbers of antiepileptic drug in use.

RESULTS

Serum α-synuclein levels were significantly increased in patients with epilepsy and acquired demyelinating disorders of the CNS compared to controls (both, p < 0.05) and showed correlation with measures of disease severity both in epilepsy (p < 0.05, r = 0.2132) and in acquired demyelinating disorders of the CNS (p < 0.05, r = 0.5892). Exosome α-synuclein showed a significant correlation with serum α-synuclein (p < 0.0001, r = 0.5915). Serum IL-1β levels were correlated only with the numbers of antiepileptic drug used in children with epilepsy (p < 0.001, r = 0.3428), suggesting drug resistant epilepsy.

CONCLUSIONS

This is the first study in children demonstrating that serum α-synuclein levels were significantly increased in children with epilepsy and with acquired demyelinating disorders of the CNS and correlated with measures of disease severity. Serum IL-1β levels showed significant correlation only with drug resistance in children with epilepsy. Thus, these data support that serum levels of α-synuclein and IL-1β are potential prognostic biomarkers for disease severity in children with epilepsy. CNS, central nervous system.

The Role of NLRP3 and IL-1β in Refractory Epilepsy Brain Injury

Objective: The objective of this study was to investigate the roles and mechanisms of inflammatory mediators NLRP3 and IL-1β in refractory temporal epilepsy brain injury.

Method: First, the brain tissue and the peripheral blood of children undergoing intractable temporal lobe epilepsy surgery were analyzed as research objects. The expression levels of NLRP3 in brain tissue and IL-1β in blood were measured. A model of temporal lobe epilepsy was established using wild-type and NLRP3 knockout 129 mice. Pilocarpine was injected intraperitoneally into the experimental group, and isovolumetric saline was injected intraperitoneally into the control group (n = 8 in each group). The expression of IL-1β in the peripheral blood, cerebral cortex, and hippocampus of mice was measured by ELISA at 3 h, 24 h, 3 days, and 7 days after modeling. Fluoro-Jade B (FJB) and TUNEL methods were used to determine necrosis and apoptosis in hippocampal neurons, respectively, and the expression of NLRP3 in the cortex was measured by immunofluorescence methods.

Result: (1) The IL-1β levels in the peripheral blood of children with intractable temporal lobe epilepsy were higher than those in the control group (t = 2.813, P = 0.01). There was also a positive correlation between IL-1β expression levels and the onset time of a single convulsion in patients with refractory epilepsy (r = 0.9735, P < 0.05). The expression level of NLRP3 in the cerebral cortex of patients with refractory temporal lobe epilepsy was higher than that in the control group. (2) The expression level of NLRP3 in the hippocampus of wild-type mice increased 3 days after modeling and decreased slightly at 7 days but remained higher than that of the control group. IL-1β levels in peripheral blood were significantly higher than those in the control group at 3 days (t = 8.259, P < 0.0001). The IL-1β levels in the peripheral blood of NLRP3 knockout mice were lower than those in the wild-type group at 3 days (t = 3.481, P = 0.004). At day 7, the neuronal necrosis and apoptosis levels in the CA3 region of the hippocampus decreased.

Conclusion: NLRP3 may be involved in the development of refractory temporal lobe epilepsy. Inhibiting NLRP3 may alleviate local brain injury by downregulating the IL-1β expression. The IL-1β levels in the peripheral blood of patients with refractory temporal lobe epilepsy may reflect the severity of convulsions.

Immune Challenges and Seizures: How Do Early Life Insults Influence Epileptogenesis?

The development of epilepsy, a process known as epileptogenesis, often occurs later in life following a prenatal or early postnatal insult such as cerebral ischemia, stroke, brain trauma, or infection. These insults share common pathophysiological pathways involving innate immune activation including neuroinflammation, which is proposed to play a critical role in epileptogenesis. This review provides a comprehensive overview of the latest preclinical evidence demonstrating that early life immune challenges influence neuronal hyperexcitability and predispose an individual to later life epilepsy. Here, we consider the range of brain insults that may promote the onset of chronic recurrent spontaneous seizures at adulthood, spanning intrauterine insults (e.g. maternal immune activation), perinatal injuries (e.g. hypoxic–ischemic injury, perinatal stroke), and insults sustained during early postnatal life—such as fever-induced febrile seizures, traumatic brain injuries, infections, and environmental stressors. Importantly, all of these insults represent, to some extent, an immune challenge, triggering innate immune activation and implicating both central and systemic inflammation as drivers of epileptogenesis. Increasing evidence suggests that pro-inflammatory cytokines such as interleukin-1 and subsequent signaling pathways are important mediators of seizure onset and recurrence, as well as neuronal network plasticity changes in this context. Our current understanding of how early life immune challenges prime microglia and astrocytes will be explored, as well as how developmental age is a critical determinant of seizure susceptibility. Finally, we will consider the paradoxical phenomenon of preconditioning, whereby these same insults may conversely provide neuroprotection. Together, an improved appreciation of the neuroinflammatory mechanisms underlying the long-term epilepsy risk following early life insults may provide insight into opportunities to develop novel immunological anti-epileptogenic therapeutic strategies.

Intranasal Delivery of miR-155-5p Antagomir Alleviates Acute Seizures Likely by Inhibiting Hippocampal Inflammation

INTRODUCTION

To confront the resistance to existing antiepileptic drugs, studies have gradually begun to investigate alternative pathologies distinct from the traditional treatments that overwhelmingly target ion channels. Microglia activation is the first inflammatory response in the brain, in which miR-155-5p plays a key proinflammatory role and thus represents a promising target for inflammatory modulation in epilepsy pathologies.

METHODS

In this study, a pentetrazol-induced acute seizure model was established, and the seizure degree was evaluated within 60 min after pentetrazol administration. Animals were then sacrificed for hippocampal tissue collection for biological experiments.

RESULTS

Intranasal delivery of miR-155-5p antagomir (30 min before pentetrazol administration) increased the percentage of animals with no induced seizures by 20%, extended the latency to generalized convulsions, and decreased seizure severity. In addition, miR-155-5p antagomir treatment alleviated hippocampal damage and decreased the expression of typical inflammatory modulators (TNF-α, IL-1β and IL-6). Further research revealed that intranasal delivery of miR-155-5p antagomir significantly decreased the relative level of miR-155-5p and increased the expression of its targets LXRα and SOCS1 in IBA1-labeled microglial cells in the hippocampus.

CONCLUSION

These findings demonstrate that intranasal delivery of miR-155-5p antagomir alleviated acute seizures, likely by blocking hippocampal inflammation. However, other potential mechanisms of the effects of miR-155-5p antagomir and its long-term safety for epilepsy treatment remain to be investigated.

Inflammation and reactive oxygen species in status epilepticus: Biomarkers and implications for therapy

Preclinical studies in immature and adult rodents and clinical observations show that neuroinflammation and oxidative stress are rapid onset phenomena occurring in the brain during status epilepticus and persisting thereafter. Notably, both neuroinflammation and oxidative stress contribute to the acute and long-term sequelae of status epilepticus thus representing potential druggable targets. Antiinflammatory drugs that interfere with the IL-1β pathway, such as anakinra, can control benzodiazepine-refractory status epilepticus in animals, and there is recent proof-of-concept evidence for therapeutic effects in children with Febrile infection related epilepsy syndrome (FIRES). Inhibitors of monoacylglycerol lipase and P2X7 receptor antagonists are also promising antiinflammatory drug candidates for rapidly aborting de novo status epilepticus and provide neuroprotection. Antiinflammatory and antioxidant drugs administered to rodents during status epilepticus and transiently thereafter, prevent long-term sequelae such as cognitive deficits and seizure progression in animals developing epilepsy. Some drugs are already in medical use and are well-tolerated, therefore, they may be considered for treating status epilepticus and its neurological consequences. Finally, markers of neuroinflammation and oxidative stress are measureable in peripheral blood and by neuroimaging, which offers an opportunity for developing prognostic and predictive mechanistic biomarkers in people exposed to status epilepticus. This article is part of the Special Issue "Proceedings of the 7th London-Innsbruck Colloquium on Status Epilepticus and Acute Seizures.

Cannabis Influences the Putative Cytokines-Related Pathway of Epilepsy among Egyptian Epileptic Patients

The study aims to investigate: (1) the prevalence of cannabis among epileptic patients seen at Mansoura University Hospital, (2) serum levels and gene expression of cytokines in epilepsy patients and the controls. and (3) the possibility that cannabis use affects the cytokine levels in epilepsy patients, triggering its future use in treatment. We recruited 440 epilepsy patients and 200 controls matched for age, gender, and ethnicity. Of the epileptic patients, 37.5% demonstrated lifetime cannabis use with a mean duration of 15 ± 73 years. Serum levels of interleukin IL-1α, IL-1β, IL-2, IL-4, IL-6, IL-8, IL-10, and tumor necrosis factor-α (TNF-α), were analyzed and gene expression analysis was conducted only for those cytokines that were different between groups in the serum analysis. The “Epilepsy-only” patients had significantly higher serum and mRNA levels of IL-1α, β, IL-2,6,8, and TNF-α compared to the controls and the “Cannabis+Epilepsy” group (p = 0.0001). IL-10 showed significantly lower levels in the “Epilepsy-only” patients compared to the controls and “Cannabis+Epilepsy” (p = 0.0001). Cannabis use is prevalent among epilepsy patients. Epilepsy is characterized by a pro-inflammatory state supported by high serum and gene expression levels. Cannabis users demonstrated significantly lower levels of inflammatory cytokines compared to epilepsy non-cannabis users which might contribute to its use in the treatment of resistant epilepsy.

Dexamethasone Attenuates Hyperexcitability Provoked by Experimental Febrile Status Epilepticus

The role of neuroinflammation in the mechanisms of epilepsy development is important because inflammatory mediators provide tractable targets for intervention. Inflammation is intrinsically involved in the generation of childhood febrile seizures (FSs), and prolonged FS [febrile status epilepticus (FSE)] precedes a large proportion of adult cases of temporal lobe epilepsy (TLE). As TLE is often refractory to therapy and is associated with serious cognitive and emotional problems, we investigated whether its development can be prevented using anti-inflammatory strategies. Using an immature rat model of FSE [experimental FSE (eFSE)], we administered dexamethasone (DEX), a broad anti-inflammatory agent, over 3 d following eFSE. We assessed eFSE-provoked hippocampal network hyperexcitability by quantifying the presence, frequency, and duration of hippocampal spike series, as these precede and herald the development of TLE-like epilepsy. We tested whether eFSE provoked hippocampal microgliosis, astrocytosis, and proinflammatory cytokine production in male and female rats and investigated blood–brain barrier (BBB) breaches as a potential contributor. We then evaluated whether DEX attenuated these eFSE sequelae. Spike series were not observed in control rats given vehicle or DEX, but occurred in 41.6% of eFSE-vehicle rats, associated with BBB leakage and elevated hippocampal cytokines. eFSE did not induce astrocytosis or microgliosis but provoked BBB disruption in 60% of animals. DEX significantly reduced spike series prevalence (to 7.6%) and frequency, and abrogated eFSE-induced cytokine production and BBB leakage (to 20%). These findings suggest that a short, postinsult intervention with a clinically available anti-inflammatory agent potently attenuates epilepsy-predicting hippocampal hyperexcitability, potentially by minimizing BBB disruption and related neuroinflammation.

Transgenerational deep sequencing revealed hypermethylation of hippocampal mGluR1 gene with altered mRNA expression of mGluR5 and mGluR3 associated with behavioral changes in Sprague Dawley rats with history of prolonged febrile seizure

The impact of febrile seizure has been shown to transcend immediate generation with the alteration of glutamatergic pathway being implicated. However, transgenerational effects of this neurological disorder particularly prolonged febrile seizure (PFS) on neurobehavioral study and methylation profile is unknown. We therefore hypothesized that transgenerational impact of prolonged febrile seizure is dependent on methylation of hippocampal mGluR1 gene. Prolonged febrile seizure was induced on post-natal day (PND) 14, by injecting lipopolysaccharide (LPS; 217μg/kg ip) and kainic acid (KA; 1.83 mg/kg ip). Sucrose preference test (SPT) and Forced swim test (FST) were carried out in the first generation (F0) of animals at PND37 and PND60. The F0 rats were decapitated at PND 14, 37 and 60 which corresponded to childhood, adolescent and adulthood respectively and their hippocampal tissue collected. The second generation (F1) rats were obtained by mating F0 generation at PND 60 across different groups, F1 rats were subjected to SPT and FST test on PND 37 only. Decapitation of F1rats and collection of hippocampal tissues were done on PND 14 and 37. Assessment of mGluR5 and mGluR3 mRNA was done with PCR while mGluR1 methylation profile was assessed with the Quantitative MassARRAY analysis. Results showed that PFS significantly leads to decreased sucrose consumption in the SPT and increased immobility time in the FST in both generations of rats. It also leads to significant decrease in mGluR5 mRNA expression with a resultant increased expression of mGluR3 mRNA expression and hypermethylation of mGluR1 gene across both generations of rats. This study suggested that PFS led to behavioral changes which could be transmitted on to the next generation in rats.

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.

Skin metabolome reveals immune responses in yellow drum Nibea albiflora to Cryptocaryon irritans infection

The yellow drum Nibea albiflora is less susceptible to Cryptocaryon irritans infection than is the case with other marine fishes such as Larimichthys crocea, Lateolabrax japonicus, and Pagrus major. To investigate further their resistance mechanism, we infected the N. albiflora with the C. irritans at a median lethal concentration of 2050 theronts/g fish. The skins of the infected and the uninfected fishes were sampled at 24 h and 72 h followed by an extensive analysis of metabolism. The study results revealed that there were 2694 potential metabolites. At 24 h post-infection, 12 metabolites were up-regulated and 17 were down-regulated whereas at 72 h post-infection, 22 metabolites were up-regulated and 26 were down-regulated. Pathway enrichment analysis shows that the differential enriched pathways were higher at 24 h with 22 categories and 58 subcategories (49 up, 9 down) than at 72 h whereby the differential enriched pathways were 6 categories and 8 subcategories (4 up, 4 down). In addition, the principal component analysis (PCA) plot shows that at 24 h the metabolites composition of infected group were separately clustered to uninfected group while at 72 h the metabolites composition in infected group were much closer to uninfected group. This indicated that C. irritans caused strong metabolic stress on the N. albiflora at 24 h and restoration of the dysregulated metabolic state took place at 72 h of infection. Also, at 72 h post infection a total of 17 compounds were identified as potential biomarkers. Furthermore, out of 2694 primary metabolites detected, 23 metabolites could be clearly identified and semi quantified with a known identification number and assigned into 66 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. Most of the enriched KEGG pathways were mainly from metabolic pathway classes, including the metabolic pathway, biosynthesis of secondary metabolites, taurine and hypotaurine metabolism, purine metabolism, linoleic acid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis. Others were glyoxylate and dicarboxylate metabolism, glutathione metabolism, and alanine, aspartate, and glutamate metabolism. Moreover, out of the identified metabolites, only 6 metabolites were statistically differentially expressed, namely, L -glutamate (up-regulated) at 24 h was important for energy and precursor for other glutathiones and instruments of preventing oxidative injury; 15-hydroxy- eicosatetraenoic acid (15-HETE), (S)-(-)-2-Hydroxyisocaproic acid, and adenine (up-regulated) at 72 h were important for anti-inflammatory and immune responses during infection; others were delta-valerolactam and betaine which were down-regulated compared to uninfected group at 72 h, might be related to immure responses including stimulation of immune system such as production of antibodies. Our results therefore further advance our understanding on the immunological regulation of N. albiflora during immune response against infections as they indicated a strong relationship between skin metabolome and C. irritans infection.

Cyclooxygenase-2 (COX-2) inhibitors: future therapeutic strategies for epilepsy management

Epilepsy, a common multifactorial neurological disease, affects about 69 million people worldwide constituting nearly 1% of the world population. Despite decades of extensive research on understanding its underlying mechanism and developing the pharmacological treatment, very little is known about the biological alterations leading to epileptogenesis. Due to this gap, the currently available antiepileptic drug therapy is symptomatic in nature and is ineffective in 30% of the cases. Mounting evidences revealed the pathophysiological role of neuroinflammation in epilepsy which has shifted the focus of epilepsy researchers towards the development of neuroinflammation-targeted therapeutics for epilepsy management. Markedly increased expression of key inflammatory mediators in the brain and blood-brain barrier may affect neuronal function and excitability and thus may increase seizure susceptibility in preclinical and clinical settings. Cyclooxygenase-2 (COX-2), an enzyme synthesizing the proinflammatory mediators, prostaglandins, has widely been reported to be induced during seizures and is considered to be a potential neurotherapeutic target for epilepsy management. However, the efficacy of such therapy involving COX-2 inhibition depends on various factors viz., therapeutic dose, time of administration, treatment duration, and selectivity of COX-2 inhibitors. This article reviews the preclinical and clinical evidences supporting the role of COX-2 in seizure-associated neuroinflammation in epilepsy and the potential clinical use of COX-2 inhibitors as a future strategy for epilepsy treatment.

Centromedian thalamic nuclei deep brain stimulation and Anakinra treatment for FIRES - Two different outcomes

Febrile infection-related epilepsy syndrome (FIRES) is a severe epilepsy disorder that affects previously healthy children. It carries high likelihood of unfavourable outcome and putative aetiology relates to an auto-inflammatory process. Standard antiepileptic drug therapies including intravenous anaesthetic agents are largely ineffective in controlling status epilepticus in FIRES. Deep brain stimulation of the centromedian thalamic nuclei (CMN-DBS) has been previously used in refractory status epilepticus in only a few cases. The use of Anakinra (a recombinant version of the human interleukin-1 receptor antagonist) has been reported in one case with FIRES with good outcome. Here we describe two male paediatric patients with FIRES unresponsive to multiple anti-epileptic drugs, first-line immune modulation, ketogenic diet and cannabidiol. They both received Anakinra and underwent CMN-DBS. The primary aim for CMN-DBS therapy was to reduce generalized seizures. CMN-DBS abolished generalized seizures in both cases and Anakinra had a positive effect in one. This patient had a favourable outcome whereas the other did not. These are the first reported cases of FIRES where CMN-DBS has been used.

Febrile convulsions during recovery after anesthesia in an infant with history of MMR vaccination: A case report

RATIONALE

Seizures are rare during the perioperative period; in most cases, there is a previous history of epilepsy or surgery-associated seizures. Febrile convulsions may occur when the body temperature rises above 38°C; this is the most common cause of seizures in children. Febrile convulsions after general anesthesia in the postanesthetic care unit (PACU) without a past or family history are rare. Some reviews suggest that since anesthesia changes immunity, elective surgery should be postponed three weeks after live vaccination.

PATIENT

A 12-month-old female with bilateral hearing loss underwent cochlear implantation under general anesthesia. She did not have any history of convulsions or developmental disorders. However, 1 week before surgery, measles-mumps-rubella (MMR) vaccination was given as a regular immunization.

DIAGNOSES

Forty minutes after arrival at the PACU, sudden generalized tonic-clonic movement occurred during recovery and the patient's measured body temperature exceeded 38.0°C.

INTERVENTIONS

Thiopental sodium was administered intravenously as an anticonvulsant, and the tonic-clonic movement stopped immediately. Endotracheal intubation was performed to secure the airway, and tepid massage and diclofenac β-dimethylaminoethanol administration were performed to lower the patient's body temperature.

OUTCOMES

There was no further fever and no seizures, and no other neurological deficits were observed until discharge.

LESSONS

The anesthesiologist should check the recent vaccination history even if the patient has not developed particular symptoms after vaccination. It is important to know that febrile convulsions may occur in patients who have recently received MMR vaccination.

Construction and disruption of spatial memory networks during development

Spatial memory, the aspect of memory involving encoding and retrieval of information regarding one's environment and spatial orientation, is a complex biological function incorporating multiple neuronal networks. Hippocampus-dependent spatial memory is not innate and emerges during development in both humans and rodents. In children, nonhippocampal dependent egocentric (self-to-object) memory develops before hippocampal-dependent allocentric (object-to-object) memory. The onset of allocentric spatial memory abilities in children around 22 mo of age occurs at an age-equivalent time in rodents when spatially tuned grid and place cells arise from patterned activity propagating through the entorhinal-hippocampal circuit. Neuronal activity, often driven by specific sensory signals, is critical for the normal maturation of brain circuits This patterned activity fine-tunes synaptic connectivity of the network and drives the emergence of specific firing necessary for spatial memory. Whereas normal activity patterns are required for circuit maturation, aberrant neuronal activity during development can have major adverse consequences, disrupting the development of spatial memory. Seizures during infancy, involving massive bursts of synchronized network activity, result in impaired spatial memory when animals are tested as adolescents or adults. This impaired spatial memory is accompanied by alterations in spatial and temporal coding of place cells. The molecular mechanisms by which early-life seizures lead to disruptions at the cellular and network levels are now becoming better understood, and provide a target for intervention, potentially leading to improved cognitive outcome in individuals experiencing early-life seizures.

Febrile seizures and increased stress sensitivity in children: How it relates to seizure characteristics

BACKGROUND

Studies suggest that the relationship between seizures and stress starts early in life. However, evidence of long-term altered stress reactivity following early-life seizures is lacking. Our objectives were to assess alterations in stress hormone reactivity in children with past febrile seizures (FS) and investigate how these alterations relate to clinical characteristics.

METHOD

This case-control study compared a convenience sample of children with simple FS (n = 24), complex FS (n = 18), and matched healthy controls (n = 42). Stress was induced by electrode placement for an electroencephalography (EEG) exam. Salivary cortisol to stress, using three samples collected before and after the stressor, was compared between groups and sex. The relationship between stress reactivity and clinical characteristics (i.e., FS duration, age at first FS, time since the last FS) was investigated.

RESULTS

Cortisol reactivity to stress was significantly different depending on study groups, F(1, 78) = 6.415, p = 0.003, η²_p = 0.141, but not sex nor was there a significant interaction between group and sex (p ≥ 0.581). Participants with simple FS showed higher cortisol reactivity to stress (M = 14.936, Standard deviation (SD) = 26.852) compared with those with complex FS (M = -4.663, SD = 18.649, p = 0.015) and controls (M = -3.817, SD = 18.907, p = 0.003). There was no significant difference between participants with complex FS and controls (p > 0.999). Stress reactivity was not linked to clinical characteristics.

CONCLUSIONS

Children with past simple FS showed greater changes in salivary cortisol following stress, suggesting enhanced stress sensitivity. As similar results were not found in a population with complex FS, our study shows that stress alterations are not caused by seizure severity. Future studies are needed to investigate whether stress sensitivity may be premorbid to simple FS and may contribute to simple FS incidence.

Role of microRNA-155 in modifying neuroinflammation and γ-aminobutyric acid transporters in specific central regions after post-ischaemic seizures

In the central nervous system, interleukin (IL)‐1β, IL‐6 and tumour necrosis factor (TNF)‐α have a regulatory role in pathophysiological processes of epilepsy. In addition, γ‐aminobutyric acid (GABA) transporter type 1 and type 3 (GAT‐1 and GAT‐3) modulate the levels of extracellular GABA in involvement in the neuroinflammation on epileptogenesis. Thus, in the current report we examined the effects of inhibiting microRNA‐155 (miR‐155) on the levels of IL‐1β, IL‐6 and TNF‐α, and expression of GAT‐1 and GAT‐3 in the parietal cortex, hippocampus and amygdala of rats with nonconvulsive seizure (NCS) following cerebral ischaemia. Real time RT‐PCR, ELISA and Western blot analysis were used to examine the miR‐155, proinflammatory cytokines (PICs) and GAT‐1/GAT‐3 respectively. With induction of NCS, the levels of miR‐155 were amplified in the parietal cortex, hippocampus and amygdala and this was accompanied with increases of IL‐1β, IL‐6 and TNF‐α. In those central areas, expression of GAT‐1 and GAT‐3 was upregulated; and GABA was reduced in rats following NCS. Intracerebroventricular infusion of miR‐155 inhibitor attenuated the elevation of PICs, amplification of GAT‐1 and GAT‐3 and impairment of GABA. Furthermore, inhibition of miR‐155 decreased the number of NCS events following cerebral ischaemia. Inhibition of miR‐155 further improved post‐ischaemia‐evoked NCS by altering neuroinflammation‐GABA signal pathways in the parietal cortex, hippocampus and amygdala. Results suggest the role of miR‐155 in regulating post‐ischaemic seizures via PICs‐GABA mechanisms.

Molecular Mechanism Involved in the Pathogenesis of Early-Onset Epileptic Encephalopathy

Recent studies have shown that neurologic inflammation may both precipitate and sustain seizures, suggesting that inflammation may be involved not only in epileptogenesis but also in determining the drug-resistant profile. Extensive literature data during these last years have identified a number of inflammatory markers involved in these processes of “neuroimmunoinflammation” in epilepsy, with key roles for pro-inflammatory cytokines such as: IL-6, IL-17 and IL-17 Receptor (IL-17R) axis, Tumor-Necrosis-Factor Alpha (TNF-α) and Transforming-Growth-Factor Beta (TGF-β), all responsible for the induction of processes of blood-brain barrier (BBB) disruption and inflammation of the Central Nervous System (CNS) itself. Nevertheless, many of these inflammatory biomarkers have also been implicated in the pathophysiologic process of other neurological diseases. Future studies will be needed to identify the disease-specific biomarkers in order to distinguish epilepsies from other neurological diseases, as well as recognize different epileptic semiology. In this context, biological markers of BBB disruption, as well as those reflecting its integrity, can be useful tools to determine the pathological process of a variety of neurological diseases. However; how these molecules may help in the diagnosis and prognostication of epileptic disorders remains yet to be determined. Herein, authors present an extensive literature review on the involvement of both, systemic and neuronal immune systems, in the early onset of epileptic encephalopathy.

Magnolia officinalis reduces the long-term effects of the status epilepticus induced by kainic acid in immature rats

During critical periods of neurodevelopment, the immature brain is susceptible to neuronal hyperexcitability, alterations such as hyperthermia, hypoxia, brain trauma or a preexisting neuroinflammatory condition can trigger, promote and prolong epileptiform activity and facilitate the development of epilepsy. The goal of the present study was to evaluate the long-term neuroprotective effects Magnolia officinalis extract, on a model of recurrent status epilepticus (SE) in immature rats. Sprague-Dawley rats were treated with kainic acid (KA) (3 mg/kg, dissolved in saline solution) beginning at day 10 P N every 24 h for five days (10 P N-14PN). Two experimental groups (KA) received two treatments for 10 days (14-24 P N): one group was treated with 300 mg/kg Magnolia Officinalis (MO) (KA-MO), and another was treated with 20 mg/kg of celecoxib (Clbx) (KA-Clbx) as a control drug. A SHAM control group at day 90 P N was established. Seizure susceptibility was analyzed through an after-discharge threshold (ADT) evaluation, and electroencephalographic activity was recorded. The results obtained from the ADT evaluation and the analysis of the electroencephalographic activity under basal conditions showed that the MO and Clbx treatments protected against epileptiform activity, and decreases long-term excitability. All rats in the KA-MO and KA-Clbx groups presented a phase I seizure on the Racine scale, corresponding to the shaking of a wet dog. In contrast, the KA group showed phase V convulsive activity on the Racine scale. Similarly, MO and Clbx exerted neuroprotective effects on hippocampal neurons and reduced gliosis in the same areas. Based on these results, early intervention with MO and Clbx treatments to prevent the inflammatory activity derived from SE in early phases of neurodevelopment exerts neuroprotective effects on epileptogenesis in adult stages.

Hyperthermia-induced seizures followed by repetitive stress are associated with age-dependent changes in specific aspects of the mouse stress system

Stress is among the most frequently self-reported factors provoking epileptic seizures in children and adults. It is still unclear, however, why some people display stress-sensitive seizures and others do not. Recently, we showed that young epilepsy patients with stress-sensitive seizures exhibit a dysregulated hypothalamic-pituitary-adrenal (HPA)-axis. Most likely, this dysregulation gradually develops, and is triggered by stressors occurring early in life (early-life stress [ELS]). ELS may be particularly impactful when overlapping with the period of epileptogenesis. To examine this in a controlled and prospective manner, the present study investigated the effect of repetitive variable stressors or control treatment between postnatal day (PND) 12 and 24 in male mice exposed on PND10 to hyperthermia (HT)-induced prolonged seizures (control: normothermia). A number of peripheral and central indices of HPA-axis activity were evaluated at pre-adolescent and young adult age (ie, at PND25 and 90, respectively). At PND25 but not at PND90, body weight gain and absolute as well as relative (to body weight) thymus weight were reduced by ELS (vs control), whereas relative adrenal weight was enhanced, confirming the effectiveness of the stress treatment. Basal and stress-induced corticosterone levels were unaffected, though, by ELS at both ages. HT by itself did not affect any of these peripheral markers of HPA-axis activity, nor did it interact with ELS. However, centrally we did observe age-specific interaction effects of HT and ELS with regard to hippocampal glucocorticoid receptor mRNA expression, neurogenesis with the immature neurone marker doublecortin and the number of hilar (ectopic) granule cells using Prox1 staining. This lends some support to the notion that exposure to repetitive stress after HT-induced seizures may dysregulate central components of the stress system in an age-dependent manner. Such dysregulation could be one of the mechanisms conferring higher vulnerability of individuals with epilepsy to develop seizures in the face of stress.

Functional deficiency in endogenous interleukin-1 receptor antagonist in patients with febrile infection-related epilepsy syndrome

OBJECTIVE

We recently reported successful treatment of a child with febrile infection-related epilepsy syndrome (FIRES), a subtype of new onset refractory status epilepticus, with the recombinant interleukin-1 (IL1) receptor antagonist (IL1RA) anakinra. On this basis, we tested whether endogenous IL1RA production or function is deficient in FIRES patients.

METHODS

Levels of IL1β and IL1RA were measured in serum and cerebrospinal fluid (CSF). The inhibitory activity of endogenous IL1RA was assessed using a cell-based reporter assay. IL1RN gene variants were identified by sequencing. Expression levels for the secreted and intracellular isoforms of IL1RA were measured in patient and control cells by real-time polymerase chain reaction.

RESULTS

Levels of endogenous IL1RA and IL1β were elevated in the serum and CSF of patients with FIRES (n = 7) relative to healthy controls (n = 10). Serum from FIRES patients drove IL1R signaling activity and potentiated IL1R signaling in response to exogenous IL1β in a cell-based reporter assay. Functional assessment of endogenous IL1RA activity in 3 FIRES patients revealed attenuated inhibition of IL1R signaling. Sequencing of IL1RN in our index patient revealed multiple variants. This was accompanied by reduced expression of intracellular but not secreted isoforms of IL1RA in the patient's peripheral blood mononuclear cells.

INTERPRETATION

Our findings suggest that FIRES is associated with reduced expression of intracellular IL1RA isoforms and a functional deficiency in IL1RA inhibitory activity. These observations may provide insight into disease pathogenesis for FIRES and other inflammatory seizure disorders and may provide a valuable biomarker for therapeutic decision-making. Ann Neurol 2019;85:526-537.

The Pharmacological Assessment of GABAA Receptor Activation in Experimental Febrile Seizures in Mice

Hyperthermia-induced febrile seizures (FSs) are the most common seizures during childhood, and prolonged complex FSs can result in the development of epilepsy. Currently, GABA_A receptor modulators such as benzodiazepines and barbiturates are used as medications for FSs with the aim of enhancing GABA-mediated inhibition of neuronal activity. However, it is still up for debate whether these enhancers of GABAergic neurotransmission could depolarize immature neurons with relatively higher levels of the intracellular Cl⁻ in the developing brain during FSs. Here, we performed simultaneous video-local field potential monitoring to determine whether benzodiazepines and barbiturates affect the phenotypes of FSs in postnatal day (P)11 and P14 mice. We found that low-dose administration of diazepam decreased the incidence of clonic seizures at P11. We also found that high-dose administration of diazepam and pentobarbital exacerbated the behavioral and electrophysiological phenotypes of the induction phase of experimental FSs at P11 but not at P14. We further found that the deteriorated phenotypes at P11 were suppressed when Na⁺K⁺2Cl⁻ cotransporter isoform 1 (NKCC1), which mediates Cl⁻ influx, was blocked by treatment with the diuretic bumetanide. Though our findings do not exclude the involvement of sedation effect of high-dose GABA_A receptor modulators in worsening experimental FSs at P11, pharmacological enhancement of GABAergic signaling could aggravate seizure activity in the early phase of FSs.

Association Analysis of Interleukin-1β, Interleukin-6, and HMGB1 Variants with Postictal Serum Cytokine Levels in Children with Febrile Seizure and Generalized Epilepsy with Febrile Seizure Plus

Background and Purpose

Febrile seizure (FS) is a unique type of seizure that only occurs during childhood. Genelized epilepsy with febrile seizure plus (GEFS+) is a familial epilepsy syndrome associated with FS and afebrile seizure (AFS). Both seizure types are related to fever, but whether genetic susceptibility to inflammation is implicated in them is still unclear. To analyze the associations between postictal serum cytokine levels and genetic variants in the cytokine genes interleukin (IL)-1β, IL-6, and high mobility group box-1 (HMGB1) in FS and GEFS+.

Methods

Genotyping was performed in 208 subjects (57 patients with FS, 43 patients with GEFS+, and 108 controls) with the SNaPshot assay for IL-1β-31 (rs1143627), IL-1β-511 (rs16944), IL-6-572 (rs1800796), and HMGB1 3814 (rs2249825). Serum IL-1β, IL-6, and HMGB1 levels were analyzed within 2 hours after seizure attacks using the ELISA in only 68 patients (38 FS, 10 GEFS+, and 20 controls). The allele distribution, genotype distribution, and correlations with serum cytokine levels were analyzed.

Results

Near-complete linkage disequilibrium exists between IL-1β-31 and IL-1β-511 variants. CT genotypes of these variants were associated with significantly higher postictal serum IL-1β levels than were CC+TT genotypes in FS (both p<0.05). CT genotypes of IL-1β-31 and IL-1β-511 variants were more strongly associated with FS than were CC+TT genotypes (odds ratio=1.691 and 1.731, respectively). For GEFS+, serum IL-1β levels after AFS for CT genotypes of IL-1β-31 and IL-1β-511 were also higher than for CC+TT genotypes. No significant associations were found for IL-6 and HMGB1.

Conclusions

Genetic variants located in IL-1β-31 and IL-1β-511 promotor regions are correlated with higher postictal IL-1β levels in FS. These results suggest that IL-1 gene cluster variants in IL-1β-31 and IL-1β-511 are a host genetic factor for provoking FS in Korean children.

Chitinase-3-like protein 1 may be a potential biomarker in patients with drug-resistant epilepsy

The mechanisms of the pathogenesis of epilepsy remain unclear. Recent research shows that the inflammatory process occurring in the brain may be a common and critical mechanism of seizures. Chitinase-3-like protein 1 (CHI3L1 or YKL-40) is a newly discovered inflammatory factor. We aimed to evaluate the role of YKL-40 as a biomarker for epilepsy. 124 subjects were classified as control group (n = 23), new-diagnosis epilepsy group (NDE, n = 34), drug responsive epilepsy group (DPE, n = 37), and drug-resistant epilepsy group (DRE, n = 30) YKL-40 was measured by ELISA in serum and cerebrospinal fluid (CSF). The concentrations of serum and CSF YKL-40 and its diagnostic accuracy for epilepsy were analysed. Patients with DRE had higher concentrations of YKL-40 in serum and CSF, while patients with NDE and DPE had increased YKL-40 levels in CSF but not serum in comparison with control. Moreover, serum and CSF YKL-40 provide high diagnostic accuracy for DRE. YKL-40 may play a possible pathogenic role in epilepsy. YKL-40 may represent a potential biomarker of brain inflammation in patients with DRE.

Pharmacological targeting of brain inflammation in epilepsy: Therapeutic perspectives from experimental and clinical studies

Increasing evidence supports a pathogenic role of unabated neuroinflammation in various central nervous system (CNS) diseases, including epilepsy. Neuroinflammation is not a bystander phenomenon of the diseased brain tissue, but it may contribute to neuronal hyperexcitability underlying seizure generation, cell loss, and neurologic comorbidities. Several molecules, which constitute the inflammatory milieu in the epileptogenic area, activate signaling pathways in neurons and glia resulting in pathologic modifications of cell function, which ultimately lead to alterations in synaptic transmission and plasticity. Herein we report the up-to-date experimental and clinical evidence that supports the neuromodulatory role of inflammatory mediators, their related signaling pathways, and involvement in epilepsy. We discuss how these mechanisms can be harnessed to discover and validate targets for novel therapeutics, which may prevent or control pharmacoresistant epilepsies.

Effect of early-life inflammation and magnesium sulfate on hyperthermia-induced seizures in infant rats: Susceptibility to pentylenetetrazol-induced seizures later in life

This study investigated the effect of inflammation and MgSO₄ pretreatment on behaviors caused by hyperthermia (HT) and the effect of these interventions on PTZ-induced seizure a week later. In this experimental study, rat pups experienced inflammation on postnatal day 10 (P10). On P18-19, the pups received either saline or MgSO₄ then subjected to hyperthermia. On P25-26, PTZ-induced seizure was initiated in the rats. Neonatal inflammation increased the susceptibility to HT-induced seizure. Inflammation and HT increased the susceptibility to PTZ-induced seizure. Pretreatment with MgSO₄ before hyperthermia decreased the susceptibility to both HT- and PTZ-induced seizure. Furthermore, calcium and magnesium blood levels significantly decreased compared to control rats. It can be concluded that neonatal inflammation potentiates while pretreatment with MgSO₄ attenuates HT-induced seizures. Also, neonatal inflammation and HT potentiate PTZ-induced seizure initiated one week later.

The role of Mean Platelet Volume/platelet count Ratio and Neutrophil to Lymphocyte Ratio on the risk of Febrile Seizure

Systemic inflammatory response has been implicated as a contributor to the onset of febrile seizures (FS). The four novel indices of the inflammatory response such as, neutrophil-to-lymphocyte ratio (NLR), mean platelet volume (MPV), platelet count (PLT) ratio and red blood cell distribution width (RDW) have been investigated in FS susceptibility and FS types (simple febrile seizure and complex febrile seizure). However, the potential role of these inflammatory markers and MPV/PLT ratio (MPR) in Chinese children with FS has yet to be fully determined. This study investigated the relevance of NLR, MPV, PLT, MPR and RDW in febrile children with and without seizures. 249 children with FS and 249 age matched controls were included in this study. NLR and MPR were calculated from complete blood cell counts prior to therapy. Differences in age, gender and these inflammatory markers between the FS group and the control group were evaluated using the chi-square test, t-test or logistic regression analysis. Receiver Operating Characteristic (ROC) curve was used to determine the optimal cut-off value of NLR and MPR for FS risk. Interactions between NLR and MPR on the additive scale were calculated by using the relative excess risk due to interaction (RERI), the proportion attributable to interaction (AP), and the synergy index (S). It has been shown that the elevated NLR and MPR levels were associated with increased risk of FS. The optimal cut-off values of NLR and MPR for FS risk were 1.13 and 0.0335 with an area under the curve (AUC) of 0.768 and 0.689, respectively. Additionally, a significant synergistic interaction between NLR and MPR was found on an additive scale. The mean levels of MPV were lower and NLR levels were higher in complex febrile seizure (CFS) than simple febrile seizure (SFS), and the differences were statistically significant. ROC analysis showed that the optimal cut-off value for NLR was 2.549 with 65.9% sensitivity and 57.5% specificity. However, no statistically significant differences were found regarding average values of MPR and RDW between CFS and SFS. In conclusion, elevated NLR and MPR add evidence to the implication of white cells subsets in FS risk, and our results confirmed that NLR is an independent, albeit limited, predictor in differentiating between CFS and SFS. Moreover, NLR and MPR may have a synergistic effect that can influence the occurrence of FS.

Detection of HHV-6 and EBV and Cytokine Levels in Saliva From Children With Seizures: Results of a Multi-Center Cross-Sectional Study

Background and Objective: One third of children with epilepsy are refractory to medications. Growing data support a role of common childhood infections with neurotropic viruses and inflammation in epileptogenesis. Our objective was to determine the frequency of Human Herpesvirus-6 (HHV-6) and Epstein-Barr Virus (EBV) infection and cytokine levels in saliva from children with seizures compared to healthy controls and to controls with a febrile illness without seizures. Methods: In this cross-sectional multi-center study, we collected saliva from 115 consecutive children with acute seizures (cases), 51 children with a fever and no seizures or underlying neurological disease (fever controls) and 46 healthy children (healthy controls). Specimens were analyzed by a novel droplet digital PCR for HHV-6 and EBV viral DNA and a bead-based immunoassay for neuroinflammatory cytokines. Results: Cases included febrile seizures (n = 30), acute seizures without (n = 53) and with fever (n = 4) in chronic epilepsy, new onset epilepsy (n = 13), febrile status epilepticus (n = 3), and first lifetime seizure (n = 12). HHV-6 DNA was found in 40% of cases vs. 37% fever controls and 35% healthy controls, with no statistically significant differences. EBV DNA was also detected with no differences in 17% cases, 16% fever controls, and 28% healthy controls. IL-8 and IL-1β were increased in saliva of 32 random samples from cases compared with 30 fever controls: IL-8 cases mean (SD): 1158.07 pg/mL (1427.41); controls 604.92 (754.04); p = 0.02. IL-1β 185.76 (230.57); controls 86.99 (187.39); p = 0.0002. IL-1β level correlated with HHV6 viral load (p = 0.007). Conclusion: Increase in inflammatory cytokines may play a role in the onset of acute seizures and saliva could represent an inexpensive and non-invasive method for detection of viral DNA and cytokines.

Benzodiazepine-refractory status epilepticus, neuroinflammation, and interneuron neurodegeneration after acute organophosphate intoxication

Nerve agents and some pesticides such as diisopropylfluorophosphate (DFP) cause neurotoxic manifestations that include seizures and status epilepticus (SE), which are potentially lethal and carry long-term neurological morbidity. Current antidotes for organophosphate (OP) intoxication include atropine, 2-PAM and diazepam (a benzodiazepine for treating seizures and SE). There is some evidence for partial or complete loss of diazepam anticonvulsant efficacy when given 30 min or later after exposure to an OP; this condition is known as refractory SE. Effective therapies for OP-induced SE are lacking and it is unclear why current therapies do not work. In this study, we investigated the time-dependent efficacy of diazepam in the nerve agent surrogate DFP model of OP intoxication on seizure suppression and neuroprotection in rats, following an early and late therapy. Diazepam (5 mg/kg, IM) controlled seizures when given 10 min after DFP exposure ("early"), but it was completely ineffective at 60 or 120 min ("late") after DFP. DFP-induced neuronal injury, neuroinflammation, and neurodegeneration of principal cells and GABAergic interneurons were significantly reduced by early but not late therapy. These findings demonstrate that diazepam failed to control seizures, SE and neuronal injury when given 60 min or later after DFP exposure, confirming the benzodiazepine-refractory SE and brain damage after OP intoxication. In addition, this study indicates that degeneration of inhibitory interneurons and inflammatory glial activation are potential mechanisms underlying these morbid outcomes of OP intoxication. Therefore, novel anticonvulsant and neuroprotectant antidotes, superior to benzodiazepines, are desperately needed for controlling nerve agent-induced SE and brain injury.

Inhibition of DPP4 enhances inhibitory synaptic transmission through activating the GLP-1/GLP-1R signaling pathway in a rat model of febrile seizures

Dipeptidyl peptidase-IV (DPP4) is a cell surface serine peptidase widely expressed in the brain. Recent studies suggest that DPP4 contributes to the development of febrile seizures (FS); however, the underlying mechanism is still unclear. Thus, we investigated the role of DPP4 in the progression of FS at the molecular and electrophysiological levels using FS models in vivo and in vitro. Herein, we found that both the mRNA and protein levels of DPP4 were upregulated in the FS model. Administration of the pharmacological DPP4 inhibitor sitagliptin suppressed the hyperthermia-induced neuronal excitability as determined via whole-cell patch-clamp recordings in vitro. Interestingly, sitagliptin administration activated the glucagon-like peptide-1 (GLP-1)/GLP-1 receptor (GLP-1R) pathway by increasing the expression of GLP-1 and GLP-1R in a rat model of FS. Moreover, administration of the GLP-1R inhibitor exendin9-39 increased seizure severity, and sitagliptin reversed the effect, as shown in the electroencephalogram (EEG) and patch-clamp results in a rat model of FS. Furthermore, the GLP-1R-mediated reduction in GABAergic transmission was enhanced by sitagliptin and DPP4 knockdown through increasing miniature inhibitory post-synaptic currents (mIPSCs) in vitro accompanied by increased synaptic release of GABA in vivo. Taken together, our results demonstrate a role of DPP4 in regulating GABAergic transmission via the GLP-1/GLP-1R pathway. These findings indicated that DPP4 may represent a novel therapeutic strategy and target for FS.

Anticonvulsant agent DPP4 inhibitor sitagliptin downregulates CXCR3/RAGE pathway on seizure models

Epilepsy is a common neurological disorder with a complex etiology. Our previous study demonstrated that dipeptidyl peptidase IV (DPP4) may be associated with the pathogenesis of epilepsy. However, whether the DPP4 inhibitor sitagliptin has an anticonvulsant effect and the underlying mechanism remain to be elucidated. In this study, we determined that sitagliptin remarkably attenuated the severity of seizures in a pentylenetetrazole (PTZ)-induced rat model. In addition, sitagliptin decreased epileptiform activity measured by electroencephalography (EEG) recordings and patch-clamp methods. Interestingly, sitagliptin pretreatment downregulated the RAGE-JAK2/STAT3 pathway and decreased the expression of CXCL4 and CXCR3. Moreover, CXCR3 knockdown decreased the expression of RAGE, JAK2 and STAT3 in cultured neurons, which suggests that CXCR3 is upstream of the RAGE-JAK2/STAT3 pathway. Altogether, our present data suggest that sitagliptin has an anticonvulsant effect, which might act via downregulation of the CXCL4/CXCR3 axis, followed by a decrease in RAGE and JAK2/STAT3 expression. Considering these effects, sitagliptin could be considered as a novel potential anticonvulsant drug.

Polymorphisms in the interleukin-1β (IL-1B) and interleukin-1α (IL-1A) genes on risk of febrile seizures: a meta-analysis

The aim of the current study was to clarify the role of four common genetic polymorphisms in the interleukin-1β (IL-1B) and interleukin-1α (IL-1A) genes on risk of febrile seizures (FS) by means of meta-analyses. We searched for studies published until February 2018 using ISI Web of Science, Pubmed, Wanfang, and Chinese National Knowledge Infrastructure databases. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using MetaAnalyst version Beta 3.13. Seventeen case-control studies were included for meta-analysis. For the IL-1B rs16944 polymorphism, the summary analysis of studies conducted among Caucasian populations showed a significant association in the CT+TT versus CC contrast (OR 1.434, 95% CI 1.153-1.785), while the pooled analysis for Asian populations yielded a significant estimate in the TT versus CC+CT comparison (OR 1.393, 95% CI 1.051-1.846). No association was observed between the IL-1B rs1143627, IL-1B rs1143634, and IL-1A rs1800587 polymorphisms and FS risk. Sensitivity analyses excluding studies showing deviation from Hardy-Weinberg equilibrium did not alter conclusions. The findings of our meta-analysis suggest that the IL-1B rs16944 polymorphism may be an important genetic determinant for FS in Caucasian and Asian populations.

Pediatric refractory and super-refractory status epilepticus

PURPOSE

To summarize the available evidence related to pediatric refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE), with emphasis on epidemiology, etiologies, therapeutic approaches, and clinical outcomes.

METHODS

Narrative review of the medical literature using MEDLINE database.

RESULTS

RSE is defined as status epilepticus (SE) that fails to respond to adequately used first- and second-line antiepileptic drugs. SRSE occurs when SE persist for 24 h or more after administration of anesthesia, or recurs after its withdrawal. RSE and SRSE represent complex neurological emergencies associated with long-term neurological dysfunction and high mortality. Challenges in management arise as the underlying etiology is not always promptly recognized and therapeutic options become limited with prolonged seizures. Treatment decisions mainly rely on case series or experts' opinions. The comparative effectiveness of different treatment strategies has not been evaluated in large prospective series or randomized clinical trials. Continuous infusion of anesthetic agents is the most common treatment for RSE and SRSE, although many questions on optimal dosing and rate of administration remain unanswered. The use of non-pharmacological therapies is documented in case series or reports with low level of evidence. In addition to neurological complications resulting from prolonged seizures, children with RSE/SRSE often develop systemic complications associated with polypharmacy and prolonged hospital stay.

CONCLUSION

RSE and SRSE are neurological emergencies with limited therapeutic options. Multi-national collaborative efforts are desirable to evaluate the safety and efficacy of current RSE/SRSE therapies, and potentially impact patients' outcomes.

Neonatal Seizure Models to Study Epileptogenesis

Current therapeutic strategies for epilepsy include anti-epileptic drugs and surgical treatments that are mainly focused on the suppression of existing seizures rather than the occurrence of the first spontaneous seizure. These symptomatic treatments help a certain proportion of patients, but these strategies are not intended to clarify the cellular and molecular mechanisms underlying the primary process of epilepsy development, i.e., epileptogenesis. Epileptogenic changes include reorganization of neural and glial circuits, resulting in the formation of an epileptogenic focus. To achieve the goal of developing “anti-epileptogenic” drugs, we need to clarify the step-by-step mechanisms underlying epileptogenesis for patients whose seizures are not controllable with existing “anti-epileptic” drugs. Epileptogenesis has been studied using animal models of neonatal seizures because such models are useful for studying the latent period before the occurrence of spontaneous seizures and the lowering of the seizure threshold. Further, neonatal seizure models are generally easy to handle and can be applied for in vitro studies because cells in the neonatal brain are suitable for culture. Here, we review two animal models of neonatal seizures for studying epileptogenesis and discuss their features, specifically focusing on hypoxia-ischemia (HI)-induced seizures and febrile seizures (FSs). Studying these models will contribute to identifying the potential therapeutic targets and biomarkers of epileptogenesis.