Inflammation in Epileptic Encephalopathies

Spontaneous Remission of Epileptic Seizures Following Norovirus Infection in a Patient With DNM1 Encephalopathy

Epileptic seizures can be worsened by infections; however, they sometimes disappear or decrease after an acute viral infection, although this is rare. We report the spontaneous remission of epileptic seizures following norovirus-induced viral gastroenteritis in a boy with DNM1 encephalopathy. He had clonic seizures daily from the age of two months and developed epileptic spasms at 14 months of age; he was admitted to the hospital at this time. A physical examination revealed hypotonia, strabismus, tongue protrusion with drooping, and widely spaced teeth. Although brain magnetic resonance imaging was unremarkable, electroencephalography revealed frequent occipital spikes. Three days after admission, the patient developed frequent diarrhea without a fever. A rapid immunochromatographic test of norovirus in a stool sample was positive. Immediately after the appearance of diarrhea, the epileptic seizures disappeared. Currently, at the age of five years, the patient has a profound psychomotor developmental delay; he has no verbal expression and is unable to walk. He has experienced involuntary movements of the myoclonus since 10 months of age. Whole-exome sequencing of the patient's DNA revealed the presence of a heterozygous de novo variant of DNM1: c.709C>T (p.Arg237Trp). Although the findings from our patient suggest that underlying neural network abnormalities were ameliorated by immunological mechanisms as a result of the viral infection, further research is needed to clarify the mechanisms behind this spontaneous remission of seizures.

Altered serum levels of platelet-derived growth factor receptor β and cluster of differentiation 13 suggest a role for pericytes in West syndrome

BACKGROUND

Pericytes play a role in the maintenance of the blood-brain barrier and neuroinflammation, attracting attention as to whether they are also involved in the pathogenesis of epilepsy.This study aimed to explore the relationship between West syndrome and pericytes.

METHODS

Eighteen Japanese pediatric West syndrome patients and nine controls aged 2 years or younger were retrospectively enrolled in this study. We assessed theserumlevels of pericyte markers, serum PDGFRβ (platelet-derived growth factor receptorβ),CD13 (aminopeptidase N), and 27 cytokines in 17 pediatric patients with West syndrome and the control group.

RESULTS

Patients with West syndrome exhibited significantly increased CD13 and decreased PDGFRβ levels, compared with controls but not serum cytokine levels. These values did not differ significantly between symptomatic and idiopathic West syndrome.

CONCLUSION

Pericytes might be implicated in the pathogenesis of West syndrome.

De novo variants in PHF21A cause intellectual developmental disorder with behavioral abnormalities and craniofacial dysmorphism with or without seizures: A case report and literature review

PURPOSE

PHF21A has been associated with intellectual developmental disorder with behavioral abnormalities and craniofacial dysmorphism with or without seizures (IDDBCS). Here, we report a new patient with IDDBCS and review previously reported patients.

METHODS

We reviewed the phenotypic and genetic spectrum of the newly diagnosed patient and previously reported patients with IDDBCS.

RESULTS

Among 12 patients (11 whose cases were previously reported and the patient whose case we report here), all patients (100%) had intellectual disability (ID) and motor development delay. Three of 8 patients (37.5%) for whom information on cognition was available had severe ID; ID was moderate in two patients (25%) and mild in three patients (37.5%). Seven of the 12 patients (58.33%) had an epileptic phenotype, and the majority (5/7, 71.42%) of affected individuals developed developmental and epileptic encephalopathy (DEE). Of the 5 patients with DEE, three developed infantile epileptic spasm syndrome (IESS). The seizures of 2 patients (2/5, 40%) were controlled by antiseizure medications. Overgrowth, ADHD, hypotonia, ASD, and sleep disorders were observed in 100%, 77.78%, 70%, 50%, and 33.33% of patients, respectively. All of the variants (100%) were de novo heterozygous variants. Three of the 12 patients (25%) had the same variant (p.Arg580*). The most common types of variants were frameshift variants (7/12, 58.33%), followed by nonsense variants (4/12, 33.33%) and missense variants (1/12, 8.33%). Genotype-phenotype relationships for IDDBCS were uncertain, as phenotypic variability was observed among patients with the same variant (p.Arg580*). The patient whose case we report here had a novel PHF21A gene variant (p.Gln97fs*20), which caused neurodevelopmental delay, macrocephaly, and IESS.

CONCLUSION

The core phenotypes of IDDBCS include neurodevelopmental delay (intellectual disability and impaired motor skills), craniofacial abnormalities, and overgrowth. ADHD, hypotonia, epilepsy, ASD, and sleep disorders are common symptoms of IDDBCS. Notably, DEE is the dominant phenotype of epilepsy, especially IESS. PHF21A may be a candidate gene for DEE. De novo variants are the main mode of inheritance. The most common types of variants are frameshift variants, and the variant p.Arg580* in PHF21A is located at a mutation hot spot.

Biochemical mechanisms in pathogenesis of infantile epileptic spasm syndrome

The molecular mechanisms leading to infantile epileptic spasm syndrome (IESS) remain obscure. The only common factor seems to be that the spasms are restricted to a limited period of infancy, during a certain maturational state. Here the current literature regarding the biochemical mechanisms of brain maturation in IESS is reviewed, and various hypotheses of the pathophysiology are put together. They include: (1) imbalance of inhibitory (NGF, IGF-1, ACTH, GABA) and excitatory factors (glutamate, nitrites) which distinguishes the different etiological subgroups, (2) abnormality of the hypothalamic pituitary adrenal (HPA) axis linking insults and early life stress, (3) inflammation (4) yet poorly known genetic and epigenetic factors, and (5) glucocorticoid and vigabatrin action on brain development, pinpointing at molecular targets of the pathophysiology from another angle. An altered maturational process may explain why so many, seemingly independent etiological factors lead to the same clinical syndrome and frequently to developmental delay. Understanding these factors can provide ideas for novel therapies.

Targeted gut microbiota manipulation attenuates seizures in a model of infantile spasms syndrome

Infantile spasms syndrome (IS) is a devastating early-onset epileptic encephalopathy associated with poor neurodevelopmental outcomes. When first-line treatment options, including adrenocorticotropic hormone and vigabatrin, are ineffective, the ketogenic diet (KD) is often employed to control seizures. Since the therapeutic impact of the KD is influenced by the gut microbiota, we examined whether targeted microbiota manipulation, mimicking changes induced by the KD, would be valuable in mitigating seizures. Employing a rodent model of symptomatic IS, we show that both the KD and antibiotic administration reduce spasm frequency and are associated with improved developmental outcomes. Spasm reductions were accompanied by specific gut microbial alterations, including increases in Streptococcus thermophilus and Lactococcus lactis. Mimicking the fecal microbial alterations in a targeted probiotic, we administered these species in a 5:1 ratio. Targeted probiotic administration reduced seizures and improved locomotor activities in control diet–fed animals, similar to KD-fed animals, while a negative control (Ligilactobacillus salivarius) had no impact. Probiotic administration also increased antioxidant status and decreased proinflammatory cytokines. Results suggest that a targeted probiotic reduces seizure frequency, improves locomotor activity in a rodent model of IS, and provides insights into microbiota manipulation as a potential therapeutic avenue for pediatric epileptic encephalopathies.

Higher levels of Bifidobacteria and tumor necrosis factor in children with drug-resistant epilepsy are associated with anti-seizure response to the ketogenic diet

Background

Recently, studies have suggested a role for the gut microbiota in epilepsy. Gut microbial changes during ketogenic diet (KD) treatment of drug-resistant epilepsy have been described. Inflammation is associated with certain types of epilepsy and specific inflammation markers decrease during KD. The gut microbiota plays an important role in the regulation of the immune system and inflammation.

Methods

28 children with drug-resistant epilepsy treated with the ketogenic diet were followed in this observational study. Fecal and serum samples were collected at baseline and three months after dietary intervention.

Findings

We identified both gut microbial and inflammatory changes during treatment. KD had a general anti-inflammatory effect. Novel bioinformatics and machine learning approaches identified signatures of specific Bifidobacteria and TNF (tumor necrosis factor) associated with responders before starting KD. During KD, taxonomic and inflammatory profiles between responders and non-responders were more similar than at baseline.

Interpretation

Our results suggest that children with drug-resistant epilepsy are more likely to benefit from KD treatment when specific Bifidobacteria and TNF are elevated. We here present a novel signature of interaction of the gut microbiota and the immune system associated with anti-epileptic response to KD treatment. This signature could be used as a prognostic biomarker to identify potential responders to KD before starting treatment. Our findings may also contribute to the development of new anti-seizure therapies by targeting specific components of the gut microbiota.

Funding

This study was supported by the Swedish Brain Foundation, Margarethahemmet Society, Stiftelsen Sunnerdahls Handikappfond, Linnea & Josef Carlssons Foundation, and The McCormick Genomic & Proteomic Center.

Involvement of Peripheral Monocytes with IL-1β in the Pathogenesis of West Syndrome

Neuroinflammation has been implicated in the pathogenesis of West syndrome (WS). Inflammatory cytokines, including interleukin-1β(IL-1β), have been reported to be associated with epilepsy. However, the assessment of cytokine changes in humans is not always simple or deterministic. This study aimed to elucidate the immunological mechanism of WS. We examined the intracellular cytokine profiles of peripheral blood cells collected from 13 patients with WS, using flow cytometry, and measured their serum cytokine levels. These were compared with those of 10 age-matched controls. We found that the WS group had significantly higher percentages of inter IL-1β, interleukin-1 receptor antagonist (IL-1RA)-positive monocytes, and interferon gamma (IFN-γ) in their CD8+ T cells than the control group. Interestingly, the group with sequelae revealed significantly lower levels of intracellular IFN-γ and IL-6 in their CD8+ T and CD4+ T cells, respectively, than the group without sequelae. There was no correlation between the ratios of positive cells and the serum levels of a particular cytokine in the WS patients. These cytokines in the peripheral immune cells might be involved in the neuroinflammation of WS, even in the absence of infectious or immune disease. Overall, an immunological approach using flow cytometry analysis might be useful for immunological studies of epilepsy.

Altered cytokine levels in cerebrospinal fluid following ketogenic diet of children with refractory epilepsy

Ketogenic diet is an effective treatment which has the potential to achieve a significant seizure reduction in drug-resistant epilepsy. The mechanism behind this effect is unclear, but one hypothesis is that the mechanism is anti-inflammatory. In this prospective study on pediatric patients we compared levels of cytokines and chemokines in the cerebrospinal fluid before and after three months on treatment to evaluate a possible anti-inflammatory effect. We analyzed 34 cytokines and chemokines in the cerebrospinal fluid of pediatric patients (n = 21) with refractory epilepsy by a multiplex assay. Beta-hydroxybutyric acid was measured in blood and cerebrospinal fluid. Seizure frequency in relation to diet treatment was assessed. For 9 different cytokines (CCL 7, CCL 21, CCL 22, CCL 25, CCL 27, IL-2, IL-10, CX3CL1 and MIF), a significant decrease ranging from 7 to 27% was seen after three months as compared to levels before the diet. In contrast, no cytokine displayed a significant increase during diet. A seizure reduction ≥ 50 % was seen in 15/21 patients (71 %) but no significant differences in cytokine decreases were found between responders and non-responders during treatment. A non-significant trend towards higher initial pre-treatment levels of cytokines was seen in responders, which were reduced following treatment. The levels of betahydroxybutyric acid were not related to seizure response. We conclude that while it is not possible to state a primary anti-inflammatory effect by dietary treatment from these data, an unequivocal immunological effect is seen and may be a part of the mechanism of ketogenic dietary treatment.

Spontaneous remission of West syndrome associated with acute infection and fever in five patients

OBJECTIVE

We analyzed the records of 198 patients with West syndrome (WS) seen at a single pediatric neurology center in Argentina between June 2004 and June 2017. Five patients with infection-related spontaneous remission of the electroclinical manifestations were identified.

METHODS

The following parameters were investigated: personal and family history, clinical characteristics of the seizures - mainly spasms - and EEG findings, type of treatment, and outcome. The inclusion criteria for WS were epileptic spasms (ES) in clusters, hypsarrhythmia, and mental deterioration. Infants with ES without hypsarrhythmia and other epileptic encephalopathies with ES were excluded.

RESULTS

Five children, four boys and one girl, met the inclusion criteria of WS with spontaneous remission after a viral infection. The etiology of ES was unknown in four patients and one had a structural etiology. All patients had spontaneous remission of the ES and normalization of the EEG following acute upper respiratory infection in four and exanthema subitum in one; all of them had fever between 38.5 and 40 °C.

CONCLUSION

We report five patients with spontaneous remission of WS following acute viral infection, associated with a respiratory virus in four and exanthema subitum in one.

The role of inflammatory mediators in epilepsy: Focus on developmental and epileptic encephalopathies and therapeutic implications

In recent years, there has been an increasing interest in the potential involvement of neuroinflammation in the pathogenesis of epilepsy. Specifically, the role of innate immunity (that includes cytokines and chemokines) has been extensively investigated either in animal models of epilepsy and in clinical settings. Developmental and epileptic encephalopathies (DEE) are a heterogeneous group of epileptic disorders, in which uncontrolled epileptic activity results in cognitive, motor and behavioral impairment. By definition, epilepsy in DEE is poorly controlled by common antiepileptic drugs but may respond to alternative treatments, including steroids and immunomodulatory drugs. In this review, we will focus on how cytokines and chemokines play a role in the pathogenesis of DEE and why expanding our knowledge about the role of neuroinflammation in DEE may be crucial to develop new and effective targeted therapeutic strategies to prevent seizure recurrence and developmental regression.

Hibiscus cannabinus L. (kenaf) studies: Nutritional composition, phytochemistry, pharmacology, and potential applications

The electronic database was searched up to July 2020, using keywords, kenaf and roselle, chemical constituents of kenaf and roselle, therapeutic uses of kenaf and roselle. Journals, books and conference proceedings were also searched. Investigations of pharmacological activities of kenaf revealed that this edible plant exhibits a broad range of therapeutic potential including antioxidant, antimicrobial, antityrosinase, anticancer, antihyperlipidemia, antiulcer, anti-inflammatory, and hepatoprotective activities. Kenaf also showed versatile utility as a functional ingredient in food, folk medicine, and animal nutritions, as well as in nanotechnology processes. The exploitation of underexploited kenaf by-products can be a significant part of waste management from an economic and environmental point of view. In addition, kenaf showed comparable nutritional, phytochemical, and pharmacological properties with Hibiscus sabdariffa (Roselle). This review has important implications for further investigations and applications of kenaf in food and pharmaceuticals industry.

Neuroinflammation in Children With Infantile Spasms: A Prospective Study Before and After Treatment With Acthar Gel (Repository Corticotropin Injection)

The selective effectiveness of adrenocorticotropic hormone (ACTH) in treating infantile spasms suggests an underlying neuroinflammation. Because neuroinflammation is mediated by activated microglia, which express translocator protein (TSPO), we imaged neuroinflammation in children with infantile spasms using positron emission tomography (PET) with ¹¹C-PK11195 (PK), which selectively binds to TSPO. Children were studied prospectively before and following treatment with Acthar Gel (repository corticotropin injection). We hypothesized that PK-PET would show neuroinflammation (increased PET uptake) in cortical and/or subcortical structures before treatment, and that this inflammation will be abolished/reduced following Acthar Gel treatment. Eight children with infantile spasms (5 males; mean age 1.8±1.1, range 0.9-4.1 years) were recruited. After clinical and video electroencephalograph (EEG) evaluation and dynamic PK-PET scan, children underwent treatment with Acthar Gel over 4 weeks, followed by repeat clinical evaluation/video-EEG 2 weeks after initiation of treatment and repeat PK-PET 2 weeks after treatment completion. Visual and quantitative analysis of PK-PET scans were performed. We calculated regional binding potential (measure of receptor-ligand binding) using a reference tissue model. Focal areas of increased PK-binding were found in the pretreatment PK-PET in 5 children. Following treatment, these increases were either reduced or normalized and were associated with cessation (n=4) or significant reduction (n=1) of spasms and complete disappearance of hypsarrhythmia. One child showed increased binding potential in basal ganglia and thalamus, despite normalization of cortical binding potential; however, these increases were likely associated with death-related causes. This study suggests Acthar Gel-responsive neuroinflammatory changes in children with infantile spasms, supporting a potential role of neuroinflammation in the pathogenesis of infantile spasms.

West syndrome: a comprehensive review

Since its first clinical description (on his son) by William James West (1793–1848) in 1841, and the definition of the classical triad of (1) infantile spasms; (2) hypsarrhythmia, and (3) developmental arrest or regression as “West syndrome”, new and relevant advances have been recorded in this uncommon disorder. New approaches include terminology of clinical spasms (e.g., infantile (IS) vs. epileptic spasms (ES)), variety of clinical and electroencephalographic (EEG) features (e.g., typical ictal phenomena without EEG abnormalities), burden of developmental delay, spectrum of associated genetic abnormalities, pathogenesis, treatment options, and related outcome and prognosis. Aside the classical manifestations, IS or ES may present with atypical electroclinical phenotypes (e.g., subtle spasms; modified hypsarrhythmia) and may have their onset outside infancy. An increasing number of genes, proteins, and signaling pathways play crucial roles in the pathogenesis. This condition is currently regarded as a spectrum of disorders: the so-called infantile spasm syndrome (ISs), in association with other causal factors, including structural, infectious, metabolic, syndromic, and immunologic events, all acting on a genetic predisposing background. Hormonal therapy and ketogenic diet are widely used also in combination with (classical and recent) pharmacological drugs. Biologically targeted and gene therapies are increasingly studied. The present narrative review searched in seven electronic databases (primary MeSH terms/keywords included West syndrome, infantile spasms and infantile spasms syndrome and were coupled to 25 secondary clinical, EEG, therapeutic, outcomes, and associated conditions terms) including MEDLINE, Embase, Cochrane Central, Web of Sciences, Pubmed, Scopus, and OMIM to highlight the past knowledge and more recent advances.

Arx expansion mutation perturbs cortical development by augmenting apoptosis without activating innate immunity in a mouse model of X-linked infantile spasms syndrome

X-linked infantile spasms syndrome (ISSX) is a clinically devastating developmental epileptic encephalopathy with life-long impact. Arx(GCG)10+7 , a mouse model of the most common triplet-repeat expansion mutation of ARX, exhibits neonatal spasms, electrographic phenotypes and abnormal migration of GABAergic interneuron subtypes. Neonatal presymptomatic treatment with 17β-estradiol (E2) in Arx(GCG)10+7 reduces spasms and modifies progression of epilepsy. Cortical pathology during this period, a crucial point for clinical intervention in ISSX, has largely been unexplored, and the pathogenic cellular defects that are targeted by early interventions are unknown. In the first postnatal week, we identified a transient wave of elevated apoptosis in Arx(GCG)10+7 mouse cortex that is non-Arx cell autonomous, since mutant Arx-immunoreactive (Arx+) cells are not preferentially impacted by cell death. NeuN+ (also known as Rbfox3) survival was also not impacted, suggesting a vulnerable subpopulation in the immature Arx(GCG)10+7 cortex. Inflammatory processes during this period might explain this transient elevation in apoptosis; however, transcriptomic and immunohistochemical profiling of several markers of inflammation revealed no innate immune activation in Arx(GCG)10+7 cortex. Neither neonatal E2 hormone therapy, nor ACTH(1-24), the frontline clinical therapy for ISSX, diminished the augmented apoptosis in Arx(GCG)10+7 , but both rescued neocortical Arx+ cell density. Since early E2 treatment effectively prevents seizures in this model, enhanced apoptosis does not solely account for the seizure phenotype, but may contribute to other aberrant brain function in ISSX. However, since both hormone therapies, E2 and ACTH(1-24), elevate the density of cortical Arx+-interneurons, their early therapeutic role in other neurological disorders hallmarked by interneuronopathy should be explored.This article has an associated First Person interview with the first author of the paper.

In search of antiepileptogenic treatments for post-traumatic epilepsy

Post-traumatic epilepsy (PTE) is diagnosed in 20% of individuals with acquired epilepsy, and can impact significantly the quality of life due to the seizures and other functional or cognitive and behavioral outcomes of the traumatic brain injury (TBI) and PTE. There is no available antiepileptogenic or disease modifying treatment for PTE. Animal models of TBI and PTE have been developed, offering useful insights on the value of inflammatory, neurodegenerative pathways, hemorrhages and iron accumulation, calcium channels and other target pathways that could be used for treatment development. Most of the existing preclinical studies test efficacy towards pathologies of functional recovery after TBI, while a few studies are emerging testing the effects towards induced or spontaneous seizures. Here we review the existing preclinical trials testing new candidate treatments for TBI sequelae and PTE, and discuss future directions for efforts aiming at developing antiepileptogenic and disease-modifying treatments.

Repetitive Diffuse Mild Traumatic Brain Injury Causes an Atypical Astrocyte Response and Spontaneous Recurrent Seizures

Focal traumatic brain injury (TBI) induces astrogliosis, a process essential to protecting uninjured brain areas from secondary damage. However, astrogliosis can cause loss of astrocyte homeostatic functions and possibly contributes to comorbidities such as posttraumatic epilepsy (PTE). Scar-forming astrocytes seal focal injuries off from healthy brain tissue. It is these glial scars that are associated with epilepsy originating in the cerebral cortex and hippocampus. However, the vast majority of human TBIs also present with diffuse brain injury caused by acceleration-deceleration forces leading to tissue shearing. The resulting diffuse tissue damage may be intrinsically different from focal lesions that would trigger glial scar formation. Here, we used mice of both sexes in a model of repetitive mild/concussive closed-head TBI, which only induced diffuse injury, to test the hypothesis that astrocytes respond uniquely to diffuse TBI and that diffuse TBI is sufficient to cause PTE. Astrocytes did not form scars and classic astrogliosis characterized by upregulation of glial fibrillary acidic protein was limited. Surprisingly, an unrelated population of atypical reactive astrocytes was characterized by the lack of glial fibrillary acidic protein expression, rapid and sustained downregulation of homeostatic proteins and impaired astrocyte coupling. After a latency period, a subset of mice developed spontaneous recurrent seizures reminiscent of PTE in human TBI patients. Seizing mice had larger areas of atypical astrocytes compared with nonseizing mice, suggesting that these atypical astrocytes might contribute to epileptogenesis after diffuse TBI.SIGNIFICANCE STATEMENT Traumatic brain injury (TBI) is a leading cause of acquired epilepsies. Reactive astrocytes have long been associated with seizures and epilepsy in patients, particularly after focal/lesional brain injury. However, most TBIs also include nonfocal, diffuse injuries. Here, we showed that repetitive diffuse TBI is sufficient for the development of spontaneous recurrent seizures in a subset of mice. We identified an atypical response of astrocytes induced by diffuse TBI characterized by the rapid loss of homeostatic proteins and lack of astrocyte coupling while reactive astrocyte markers or glial scar formation was absent. Areas with atypical astrocytes were larger in animals that later developed seizures suggesting that this response may be one root cause of epileptogenesis after diffuse TBI.

Chemokines as new inflammatory players in the pathogenesis of epilepsy

A large series of clinical and experimental studies supports a link between inflammation and epilepsy, indicating that inflammatory processes within the brain are important contributors to seizure recurrence and precipitation. Systemic inflammation can precipitate seizures in children suffering from epileptic encephalopathies, and hallmarks of a chronic inflammatory state have been found in patients with temporal lobe epilepsy. Research performed on animal models of epilepsy further corroborates the idea that seizures upregulate inflammatory mediators, which in turn may enhance brain excitability and neuronal degeneration. Several inflammatory molecules and their signaling pathways have been implicated in epilepsy. Among these, the chemokine pathway has increasingly gained attention. Chemokines are small cytokines secreted by blood cells, which act as chemoattractants for leukocyte migration. Recent studies indicate that chemokines and their receptors are also produced by brain cells, and are involved in various neurological disorders including epilepsy. In this review, we will focus on a subset of pro-inflammatory chemokines (namely CCL2, CCL3, CCL5, CX3CL1) and their receptors, and their increasingly recognized role in seizure control.