Sex differences in cholinergic signaling affect functional outcomes for theta-gamma coordination in hippocampal subcircuits following experimental febrile status epilepticus.

OBJECTIVE: Sex determines cognitive outcome in animal models of early life seizure, where males exhibit impaired hippocampal-dependent learning and memory compared with females. The physiological underpinnings of this sex effect are unclear. Cholinergic signaling is essential for the generation of hippocampal oscillations, and supplementation of cholinergic precursors prior to status epilepticus in immature male rats prevents subsequent memory deficits. We hypothesized that there are sex differences in acetylcholine circuits and their response to experimental febrile status epilepticus (eFSE). METHODS: eFSE was induced in male and female rat pups. We transversed the hippocampus of postnatal day >60 control (CTL) and eFSE rats with a 64-channel laminar silicon probe to assay cholinergic-dependent theta oscillations under urethane anesthesia. Local field potential properties were compared during (1) baseline sensory stimulation, (2) pharmacological stimulation via acetylcholine reuptake blockade, and (3) sensory stimulation after muscarinic acetylcholine receptor block (atropine). RESULTS: In all groups, a baseline tail pinch could elicit theta oscillations via corticohippocampal synaptic input. Following atropine, a tail pinch response could no longer be elicited in CTL male, CTL female, or eFSE female rats. In contrast, induced slow theta power in eFSE males after atropine was not decreased to spontaneous levels. Analysis of oscillation bandwidths revealed sex differences in acetylcholine modulation of theta frequency and slow gamma frequency and power. This study also identified significant effects of both sex and eFSE on baseline theta-gamma comodulation, indicating a loss of coupling in eFSE males and a potential gain of function in eFSE females. SIGNIFICANCE: There are differences in cholinergic modulation of theta and gamma signal coordination between male and female rats. These differences may underlie worse cognitive outcomes in males following eFSE. Promoting the efficacy of muscarinic acetylcholine signaling prior to or following early life seizures could elucidate a mechanism for the temporal discoordination of neural signals within and between hippocampus and neocortex and provide a novel therapeutic approach for improving cognitive outcomes.

The Impact of Inflammation on Thermal Hyperpnea: Relevance for Heat Stress and Febrile Seizures.

Extreme heat caused by climate change is increasing the transmission of infectious diseases, resulting in a sharp rise in heat-related illness and mortality. Understanding the mechanistic link between heat, inflammation, and disease is thus important for public health. Thermal hyperpnea, and consequent respiratory alkalosis, is crucial in febrile seizures and convulsions induced by heat stress in humans. Here, we address what causes thermal hyperpnea in neonates and how it is affected by inflammation. Transient receptor potential cation channel subfamily V member 1 (TRPV1), a heat-activated channel, is sensitized by inflammation and modulates breathing and thus may play a key role. To investigate whether inflammatory sensitization of TRPV1 modifies neonatal ventilatory responses to heat stress, leading to respiratory alkalosis and an increased susceptibility to hyperthermic seizures, we treated neonatal rats with bacterial LPS, and breathing, arterial pH, in vitro vagus nerve activity, and seizure susceptibility were assessed during heat stress in the presence or absence of a TRPV1 antagonist (AMG-9810) or shRNA-mediated TRPV1 suppression. LPS-induced inflammatory preconditioning lowered the threshold temperature and latency of hyperthermic seizures. This was accompanied by increased tidal volume, minute ventilation, expired CO2, and arterial pH (alkalosis). LPS exposure also elevated vagal spiking and intracellular calcium concentrations in response to hyperthermia. TRPV1 inhibition with AMG-9810 or shRNA reduced the LPS-induced susceptibility to hyperthermic seizures and altered the breathing pattern to fast shallow breaths (tachypnea), making each breath less efficient and restoring arterial pH. These results indicate that inflammation exacerbates thermal hyperpnea-induced respiratory alkalosis associated with increased susceptibility to hyperthermic seizures, primarily mediated by TRPV1 localized to vagus neurons.

Functional network connectivity imprint in febrile seizures.

Complex febrile seizures (CFS), a subset of paediatric febrile seizures (FS), have been studied for their prognosis, epileptogenic potential and neurocognitive outcome. We evaluated their functional connectivity differences with simple febrile seizures (SFS) in children with recent-onset FS. Resting-state fMRI (rs-fMRI) datasets of 24 children with recently diagnosed FS (SFS-n = 11; CFS-n = 13) were analysed. Functional connectivity (FC) was estimated using time series correlation of seed region-to-whole-brain-voxels and network topology was assessed using graph theory measures. Regional connectivity differences were correlated with clinical characteristics (FDR corrected p < 0.05). CFS patients demonstrated increased FC of the bilateral middle temporal pole (MTP), and bilateral thalami when compared to SFS. Network topology study revealed increased clustering coefficient and decreased participation coefficient in basal ganglia and thalamus suggesting an inefficient-unbalanced network topology in patients with CFS. The number of seizure recurrences negatively correlated with the integration of Left Thalamus (r = - 0.58) and FC of Left MTP to 'Right Supplementary Motor and left Precentral' gyrus (r = - 0.53). The FC of Right MTP to Left Amygdala, Putamen, Parahippocampal, and Orbital Frontal Cortex (r = 0.61) and FC of Left Thalamus to left Putamen, Pallidum, Caudate, Thalamus Hippocampus and Insula (r 0.55) showed a positive correlation to the duration of the longest seizure. The findings of the current study report altered connectivity in children with CFS proportional to the seizure recurrence and duration. Regardless of the causal/consequential nature, such observations demonstrate the imprint of these disease-defining variables of febrile seizures on the developing brain.

Acute encephalopathy with biphasic seizures and late reduced diffusion: Predictive EEG findings.

BACKGROUND: Acute encephalopathy with biphasic seizures and late reduced diffusion (AESD) is a common type of acute encephalopathy in Japan; the condition is clinically characterized by prolonged seizures as the initial neurological symptom, followed by late seizures 4-6 days later. It is difficult to differentiate AESD from prolonged febrile seizures (PFSs). Here, we explored the use of electroencephalography to differentiate AESD from PFSs. METHODS: We studied the electroencephalograms (EEGs) of children <6 years of age diagnosed with AESD or PFSs; all EEGs were recorded within 48 h of seizure onset (i.e., before the late seizures of AESD). Two pediatric neurologists evaluated all EEGs, focusing on the basic rhythm, slowing during wakefulness/arousal by stimuli, spindles, fast waves, and slowing during sleep. RESULTS: The EEGs of 14 children with AESD and 31 children with PFSs were evaluated. Spindles were more commonly reduced or absent in children with AESD than in those with PFSs (71% vs. 31%, p = 0.021). Fast waves were also more commonly reduced or absent in children with AESD (21% vs. 0%, p = 0.030). The rates of all types of slowing did not differ between children with AESD and those with PFSs, but continuous or frequent slowing during sleep was more common in the former (50% vs. 17%, p = 0.035). CONCLUSIONS: EEG findings may usefully differentiate AESD from PFSs. Reduced or absent spindles/fast waves and continuous or frequent slowing during sleep are suggestive of AESD in children with prolonged seizures associated with fever.

Early Life Febrile Seizures Impair Hippocampal Synaptic Plasticity in Young Rats.

Febrile seizures (FSs) in early life are significant risk factors of neurological disorders and cognitive impairment in later life. However, existing data about the impact of FSs on the developing brain are conflicting. We aimed to investigate morphological and functional changes in the hippocampus of young rats exposed to hyperthermia-induced seizures at postnatal day 10. We found that FSs led to a slight morphological disturbance. The cell numbers decreased by 10% in the CA1 and hilus but did not reduce in the CA3 or dentate gyrus areas. In contrast, functional impairments were robust. Long-term potentiation (LTP) in CA3-CA1 synapses was strongly reduced, which we attribute to the insufficient activity of N-methyl-D-aspartate receptors (NMDARs). Using whole-cell recordings, we found higher desensitization of NMDAR currents in the FS group. Since the desensitization of NMDARs depends on subunit composition, we analyzed NMDAR current decays and gene expression of subunits, which revealed no differences between control and FS rats. We suggest that an increased desensitization is due to insufficient activation of the glycine site of NMDARs, as the application of D-serine, the glycine site agonist, allows the restoration of LTP to a control value. Our results reveal a new molecular mechanism of FS impact on the developing brain.

A study on the relationship between non-epileptic fast (40 - 200 Hz) oscillations in scalp EEG and development in children.

OBJECTIVE: Physiological gamma and ripple activities may be linked to neurocognitive functions. This study investigated the relationship between development and non-epileptic, probably physiological, fast (40-200 Hz) oscillations (FOs) including gamma (40 - 80 Hz) and ripple (80 - 200 Hz) oscillations in scalp EEG in children with neurodevelopmental disorders. METHODS: Participants were 124 children with autism spectrum disorder (ASD) and/or attention deficit/hyperactivity disorder (ADHD). Gamma and ripple oscillations were explored from 60-second-long sleep EEG data in each subject using a semi-automatic detection tool supplemented with visual confirmation and time-frequency analysis. RESULTS: Gamma and ripple oscillations were detected in 25 (20.2%) and 22 (17.7%) children, respectively. The observation of one or more occurrence(s) of ripple oscillations, but not gamma oscillations, was significantly related to lower age at EEG recording (odds ratio, OR: 0.727 [95% confidence interval, CI: 0.568-0.929]), higher intelligence/developmental quotient (OR: 1.041, 95% CI: 1.002-1.082), and lack of a diagnosis with ADHD (OR: 0.191, 95% CI: 0.039 - 0.937) according to a binominal logistic regression analysis that included diagnosis with ASD, sex, history of perinatal complications, history of febrile seizures, and use of a sedative agent for the EEG recording as the other non-significant parameters. Diagnostic group was not related to frequency or power of spectral peaks of FOs. CONCLUSION: The production of non-epileptic scalp ripples was confirmed to be associated with brain development and function/dysfunction in childhood. Further investigation is necessary to interpret all of the information on higher brain functions that may be embedded in scalp FOs.

Neocortex- and hippocampus-specific deletion of Gabrg2 causes temperature-dependent seizures in mice.

Mutations in the GABRG2 gene encoding the γ-aminobutyric acid (GABA) A receptor gamma 2 subunit are associated with genetic epilepsy with febrile seizures plus, febrile seizures plus, febrile seizures, and other symptoms of epilepsy. However, the mechanisms underlying Gabrg2-mediated febrile seizures are poorly understood. Here, we used the Cre/loxP system to generate conditional knockout (CKO) mice with deficient Gabrg2 in the hippocampus and neocortex. Heterozygous CKO mice (Gabrg2fl/wtCre+) exhibited temperature-dependent myoclonic jerks, generalised tonic-clonic seizures, increased anxiety-like symptoms, and a predisposition to induce seizures. Cortical electroencephalography showed the hyperexcitability in response to temperature elevation in Gabrg2fl/wtCre+ mice, but not in wild-type mice. Gabrg2fl/wtCre+ mice exhibited spontaneous seizures and susceptibility to temperature-induced seizures. Loss of neurons were observed in cortical layers V-VI and hippocampus of Gabrg2fl/wtCre+ mice. Furthermore, the latency of temperature- or pentylenetetrazol-induced seizures were significantly decreased in Gabrg2fl/wtCre+ mice compared with wild-type mice. In summary, Gabrg2fl/wtCre+ mice with Gabrg2 deletion in the neocortex and hippocampus reproduce many features of febrile seizures and therefore provide a novel model to further understand this syndrome at the cellular and molecular level.

TMEM16C is involved in thermoregulation and protects rodent pups from febrile seizures.

Febrile seizures (FSs) are the most common convulsion in infancy and childhood. Considering the limitations of current treatments, it is important to examine the mechanistic cause of FSs. Prompted by a genome-wide association study identifying TMEM16C (also known as ANO3) as a risk factor of FSs, we showed previously that loss of TMEM16C function causes hippocampal neuronal hyperexcitability [Feenstra et al., Nat. Genet. 46, 1274-1282 (2014)]. Our previous study further revealed a reduction in the number of warm-sensitive neurons that increase their action potential firing rate with rising temperature of the brain region harboring these hypothalamic neurons. Whereas central neuronal hyperexcitability has been implicated in FSs, it is unclear whether the maximal temperature reached during fever or the rate of body temperature rise affects FSs. Here we report that mutant rodent pups with TMEM16C eliminated from all or a subset of their central neurons serve as FS models with deficient thermoregulation. Tmem16c knockout (KO) rat pups at postnatal day 10 (P10) are more susceptible to hyperthermia-induced seizures. Moreover, they display a more rapid rise of body temperature upon heat exposure. In addition, conditional knockout (cKO) mouse pups (P11) with TMEM16C deletion from the brain display greater susceptibility of hyperthermia-induced seizures as well as deficiency in thermoregulation. We also found similar phenotypes in P11 cKO mouse pups with TMEM16C deletion from Ptgds-expressing cells, including temperature-sensitive neurons in the preoptic area (POA) of the anterior hypothalamus, the brain region that controls body temperature. These findings suggest that homeostatic thermoregulation plays an important role in FSs.

Birth characteristics and risk of febrile seizures.

OBJECTIVE: Febrile seizure is a common childhood disorder that affects 2-5% of all children, and is associated with later development of epilepsy and psychiatric disorders. This study determines how the incidence of febrile seizures correlates with birth characteristics, age, sex and brain development. METHODS: This is a cohort study of all children born Denmark between 1977 and 2011 who were alive at 3 months of age (N = 2,103,232). The Danish National Patient Register was used to identify children with febrile seizures up to 5 years of age. Follow-up ended on 31 December 2016 when all cohort members had potentially reached 5 years of age. RESULTS: In total, 75,593 (3.59%, 95% CI: 3.57-3.62%) were diagnosed with febrile seizures. Incidence peaked at 16.7 months of age (median: 16.7 months, interquartile range: 12.5-24.0). The 5-year cumulative incidence of febrile seizures increased with decreasing birth weight (<1500 g; 5.42% (95% CI: 4.98-5.88% vs. 3,000-4,000 g; 3.53% (95% CI: 3.50-3.56%)) and with decreasing gestational age at birth (31-32 weeks; 5.90% (95% CI: 5.40-6.44%) vs. 39-40 weeks; 3.56% (95% CI: 3.53-3.60)). Lower gestational age at birth was associated with higher age at onset of a first febrile seizure; an association that essentially disappeared when correcting for age from conception. CONCLUSIONS: The risk of febrile seizures increased with decreasing birth weight and gestational age at birth. The association between low gestational age at birth and age at first febrile seizure suggests that onset of febrile seizures is associated with the stage of brain development.

Acute encephalopathy with biphasic seizures and late reduced diffusion; posterior frontal hyperperfusion before late seizures revealed by arterial spin labeling: A case report.

BACKGROUND: Arterial spin labeling, a magnetic resonance imaging modality that can evaluate cerebral perfusion without using a contrast material or ionizing radiation, is becoming increasingly accessible. However, only a few reports have used this method to assess the perfusion abnormalities observed in acute encephalopathy with biphasic seizures and late reduced diffusion. PATIENT DESCRIPTION: A 10-month-old Japanese girl presented with febrile status epilepticus (early seizures). Her convulsions ceased after the administration of intravenous phenobarbital, although her impaired consciousness was protracted. Five days later, diffusion-weighted imaging revealed slightly high signal intensity lesions in the bilateral posterior frontal areas. Arterial spin labeling revealed bilateral frontal-dominant hypoperfusion and posterior frontal hyperperfusion. On day 6, she had three convulsions (late seizures) and was diagnosed with acute encephalopathy with biphasic seizures and late reduced diffusion. She received treatment accordingly and recovered eventually. DISCUSSION: Based on previous reports, hypoperfusion within 1-2 days of early seizures and hyperperfusion accompanied by bright tree appearance on diffusion-weighted imaging within 1-2 days of late seizures are typical in acute encephalopathy with biphasic seizures and late reduced diffusion. In our patient, the first magnetic resonance imaging scan was performed one day prior to the onset of late seizures. We observed posterior frontal hyperperfusion accompanied by high signals on diffusion-weighted imaging, which leads us to speculate that this could be a predictive marker of late seizures.

Body temperature predicts recurrent febrile seizures in the same febrile illness.

BACKGROUND: The incidence of recurrent febrile seizures during the same febrile illness (RFS) is 14-24%. A pilot study found that body temperature and male sex were predictors of RFS. This study sought to validate body temperature as a predictor of RFS, calculate the optimal cut-off body temperature for predicting RFS, and identify the other predictors of RFS. METHODS: This prospective cohort study enrolled children with febrile seizures aged 6-60 months who visited the emergency department at Atsugi City Hospital, Japan, between March 1, 2019, and February 29, 2020. Children who had multiple seizures, diazepam administration before the emergency department visit, seizures lasting >15 min, underlying diseases, or who could not be followed up were excluded. The optimal cut-off body temperature was determined using a receiver-operating characteristic curve. RESULTS: A total of 109 children were enrolled, of whom 13 (11.9%) had RFS. A lower body temperature was significantly associated with RFS (P = 0.02). The optimal cut-off body temperature for predicting RFS was 39.2 °C. Children with RFS also had significantly lower C-reactive protein and blood glucose levels (P = 0.01 and 0.047, respectively), but none of the other factors considered were significantly associated with RFS. CONCLUSIONS: This large prospective study confirmed that body temperature is a predictor of RFS. The optimal cut-off body temperature for predicting RFS was 39.2 °C. Low C-reactive protein level and blood glucose level might be predictors of RFS, but this needs to be confirmed in prospective multicenter studies.

Augmented seizure susceptibility and hippocampal epileptogenesis in a translational mouse model of febrile status epilepticus.

OBJECTIVE: Prolonged fever-induced seizures (febrile status epilepticus [FSE]) during early childhood increase the risk for later epilepsy, but the underlying mechanisms are incompletely understood. Experimental FSE (eFSE) in rats successfully models human FSE, recapitulating the resulting epileptogenesis in a subset of affected individuals. However, the powerful viral and genetic tools that may enhance mechanistic insights into epileptogenesis and associated comorbidities, are better-developed for mice. Therefore, we aimed to determine if eFSE could be generated in mice and if it provoked enduring changes in hippocampal-network excitability and the development of spontaneous seizures. METHODS: We employed C57BL/6J male mice, the strain used most commonly in transgenic manipulations, and examined if early life eFSE could be sustained and if it led to hyperexcitability of hippocampal networks and to epilepsy. Outcome measures included vulnerability to the subsequent administration of the limbic convulsant kainic acid (KA) and the development of spontaneous seizures. In the first mouse cohort, adult naive and eFSE-experiencing mice were exposed to KA. A second cohort of control and eFSE-experiencing young adult mice was implanted with bilateral hippocampal electrodes and recorded using continuous video-electroencephalography (EEG) for 2 to 3 months to examine for spontaneous seizures (epileptogenesis). RESULTS: Induction of eFSE was feasible and eFSE increased the susceptibility of adult C57BL/6J mice to KA, thereby reducing latency to seizure onset and increasing seizure severity. Of 24 chronically recorded eFSE mice, 4 (16.5%) developed hippocampal epilepsy with a latent period of ~3 months, significantly different from the expectation by chance (P = .04). The limbic epilepsy that followed eFSE was progressive. SIGNIFICANCE: eFSE promotes pro-epileptogenic network changes in a majority of C57BL/6J male mice and frank "temporal lobe-like" epilepsy in one sixth of the cohort. Mouse eFSE may thus provide a useful tool for investigating molecular, cellular, and circuit changes during the development of temporal lobe epilepsy and its comorbidities.

Cannabidiol inhibits febrile seizure by modulating AMPA receptor kinetics through its interaction with the N-terminal domain of GluA1/GluA2.

Cannabidiol (CBD) is a major phytocannabinoid in Cannabis sativa. CBD is being increasingly reported as a clinical treatment for neurological diseases. Febrile seizure is one of the most common diseases in children with limited therapeutic options. We investigated possible therapeutic effects of CBD on febrile seizures and the underlying mechanism. Use of a hyperthermia-induced seizures model revealed that CBD significantly prolonged seizure latency and reduced the severity of thermally-induced seizures. Hippocampal neuronal excitability was significantly decreased by CBD. Further, CBD significantly reduced the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) mediated evoked excitatory postsynaptic currents (eEPSCs) and the amplitude and frequency of miniature EPSCs (mEPSCs). Furthermore, CBD significantly accelerated deactivation in GluA1 and GluA2 subunits. Interestingly, CBD slowed receptor recovery from desensitization of GluA1, but not GluA2. These effects on kinetics were even more prominent when AMPAR was co-expressed with γ-8, the high expression isoform 8 of transmembrane AMPAR regulated protein (TARPγ8) in the hippocampus. The inhibitory effects of CBD on AMPAR depended on its interaction with the distal N-terminal domain of GluA1/GluA2. CBD inhibited AMPAR activity and reduced hippocampal neuronal excitability, thereby improving the symptoms of febrile seizure in mice. The putative binding site of CBD in the N-terminal domain of GluA1/GluA2 may be a drug target for allosteric gating modulation of AMPAR.

Current understanding of febrile seizures and their long-term outcomes.

In this paper we reframe febrile seizures, which are viewed as a symptom of an underlying brain disorder. The general observation is that a small cohort of children will develop febrile seizures (2-5% in the West), while the greater majority will not. This suggests that the brain that generates a seizure, in an often-mild febrile context, differs in some ways from the brain that does not. While the underlying brain disorder appears to have no significant adverse implication in the majority of children with febrile seizures, serious long-term outcomes (cognitive and neuropsychiatric) have been recently reported, including sudden death. These adverse events likely reflect the underlying intrinsic brain pathology, as yet undefined, of which febrile seizures are purely a manifestation and not the primary cause. A complex interaction between brain-genetics-epigenetics-early environment is likely at play. In view of this emerging data, it is time to review whether febrile seizures are a single entity, with a new and multidimensional approach needed to help with predicting outcome. WHAT THIS PAPER ADDS: A febrile seizure is due to a brain's aberrant response to high temperature. Problems in a small group of children are now being identified later in life. There is no clear correlation between duration or other characteristics of febrile seizures and subsequent mesial temporal sclerosis.

Phenotypic spectrum of patients with GABRB2 variants: from mild febrile seizures to severe epileptic encephalopathy.

AIM: To characterize the different phenotypes of GABRB2-related epilepsy and to establish a genotype-phenotype correlation. METHOD: We used next-generation sequencing to identify GABRB2 variants in 15 patients. RESULTS: Eleven GABRB2 variants were novel and 12 were de novo. The age at the onset of seizures ranged from 1 day to 26 months. Nine patients had multiple seizure types, including focal seizures, generalized tonic-clonic seizures, myoclonic seizures, epileptic spasms, and atonic seizures. Seizures were fever-sensitive in 13 out of the 15 patients. Eleven patients displayed developmental delay, while 11 had abnormal video electroencephalography. Abnormalities in the brain images included dysplasia of the frontal and temporal cortex, dysplasia of the corpus callosum, and delayed myelination in four patients. One patient was diagnosed with febrile seizures, three with febrile seizures plus, three with Dravet syndrome, three with West syndrome, one with Ohtahara syndrome, three with developmental delays and epilepsy, and one with non-specific early-onset epileptic encephalopathy. INTERPRETATION: The most common phenotypes of patients with GABRB2 variants include early onset of seizure and fever sensitivity. Febrile seizures and febrile seizures plus are new phenotypes of GABRB2 variants. The phenotypic spectrum of GABRB2 variants ranges from mild febrile seizures to severe epileptic encephalopathy.

De novo truncating mutation in SCN1A as a cause of febrile seizures plus (FS+).

SCN1A is one of the most relevant epilepsy genes. In general, de novo severe mutations, such as truncating mutations, lead to a classic form of Dravet syndrome (DS), while missense mutations are associated with both DS and milder phenotypes within the GEFS+ spectrum, however, these phenotype-genotype correlations are not entirely consistent. Case report. We report an 18-year-old woman with a history of recurrent febrile generalized tonic-clonic seizures (GTCS) starting at age four months and afebrile asymmetric GTCS and episodes of arrest, suggestive of focal impaired awareness seizures, starting at nine months. Her psychomotor development was normal. Sequencing of SCN1A revealed a heterozygous de novo truncating mutation (c.5734C>T, p.Arg1912X) in exon 26. Conclusion. Truncating mutations in SCN1A may be associated with milder phenotypes within the GEFS+ spectrum. Accordingly, SCN1A gene testing should be performed as part of the assessment for sporadic patients with mild phenotypes that fit within the GEFS+ spectrum, since the finding of a mutation has diagnostic, therapeutic and genetic counselling implications.

Transient cortical diffusion restriction in children immediately after prolonged febrile seizures.

AIM: Little is known about acute febrile status epilepticus-induced injury of extrahippocampal structures. To clarify the presence and clinical significance of acute extrahippocampal injuries, we performed diffusion-weighted imaging (DWI) in children immediately after prolonged febrile seizure (PFS). METHOD: We performed a retrospective cohort study in children younger than 6 years old who visited one of two hospitals due to PFSs between January 2013 and October 2018. PFS was defined as a febrile seizure that persisted for 15 min or longer. We collected brain DWI data within 6 h of the end of PFS. When the initial DWI detected an abnormality, a follow-up DWI was performed a few days later. RESULTS: The study population consisted of 101 patients with PFSs. DWI was performed within 6 h in 51 patients, while the remaining 50 patients did not undergo imaging because of good recovery of consciousness. Restricted cortical diffusion was evident in 9 (18%) patients on initial DWI. All of them underwent DWI within 100 min after PFS. Restricted cortical diffusion was associated with male sex, asymmetrical PFS symptoms, and a shorter duration between the end of the seizure and DWI, but was not associated with seizure duration. All cortical abnormalities had resolved on follow-up DWI of these patients within 72 h after the initial imaging, but ipsilateral hippocampal hyperintensity appeared in one patient. All 9 patients with restricted cortical diffusion were finally diagnosed with PFS and discharged without sequelae. CONCLUSIONS: Some children with PFSs exhibit transient restricted diffusion in the regional cortex on DWI performed immediately after the end of PFS. These transient diffusion changes were not associated with unfavorable epileptic sequelae or neuroimaging in the short-term.

Protective effects of maternal administration of curcumin and hesperidin in the rat offspring following repeated febrile seizure: Role of inflammation and TLR4.

Neuroinflammation has a key role in seizure generation and perpetuation in the neonatal period, and toll-like receptor 4 (TLR4) pathway has a prominent role in neuroinflammatory diseases. Administration of antioxidants and targeting TLR4 in the embryonic period may protect rat offspring against the next incidence of febrile seizure and its harmful effects. Curcumin and hesperidin are natural compounds with anti-inflammatory and antioxidant properties and have an inhibitory action on TLR4 receptors. We evaluated the effect of maternal administration of curcumin and hesperidin on infantile febrile seizure and subsequent memory dysfunction in adulthood. Hyperthermia febrile seizure was induced on postnatal days 9-11 on male rat pups with 24 h intervals, in a Plexiglas box that was heated to ~45 °C by a heat lamp. We used enzyme-linked immunosorbent assay, Western blotting, malondialdehyde (MDA), and glutathione (GSH) assessment for evaluation of inflammatory cytokine levels, TLR4 protein expression, and oxidative responses in the hippocampal tissues. For assessing working memory and long-term potentiation, the double Y-maze test and Schaffer collateral-CA1 in vivo electrophysiological recording were performed, respectively Our results showed that curcumin and hesperidin decreased TNF-α, IL-10, and TLR4 protein expression and reversed memory dysfunction. However, they did not provoke a significant effect on GSH content or amplitude and slope of recorded fEPSPs in the hippocampus. In addition, curcumin, but not hesperidin, decreased interleukin-1ß (IL-1ß) and MDA levels. These findings imply that curcumin and hesperidin induced significant protective effects on febrile seizures, possibly via their anti-inflammatory and antioxidant properties and downregulation of TLR4.

Glutamatergic pathway in depressive-like behavior associated with pentylenetetrazole rat model of epilepsy with history of prolonged febrile seizures.

BACKGROUND: Depression is the most significant cause of suicide among neuropsychiatric illnesses. Major depression further affects the quality of life in an individual with epilepsy. The treatment of depression in an epileptic patient could be very challenging because of drug selection or the fact that some antiepileptic drugs are known to cause depression. It has been shown that in addition to the known involvement of the serotonergic pathway in depression, the glutamatergic system is also involved in the evolution of the disease, but this knowledge is limited. This study assessed if induction of epilepsy in rats will cause depressive-like behavior, alters the concentrations of metabotropic receptor 5 (mGluR5), glutamate transport protein (GLAST), glutamate synthase (GS) and brain derived neurotrophic factor (BDNF). MATERIALS AND METHOD: Epilepsy was induced in rats by injecting Pentylenetetrazole at 35 mg/kg every other day. At kindle, rats were subjected to sucrose preference test (SPT) and forced swim test (FST) and decapitated 4 h later. Hippocampal tissue was collected and the BDNF concentration was measured with ELISA; mGluR5 and GS protein expression was measured using western blot while amygdala tissue was used for GLAST expression with flow cytometry. RESULTS: Our results showed that epilepsy leads to depressive-like behavior in rats and alters the glutamatergic system. CONCLUSION: Therefore, we conclude that targeting the glutamate pathway may be a good strategy to alleviate depressive-like behavior associated with epilepsy.