New roles for interleukin-1 Beta in the mechanisms of epilepsy

Contribution of microglia to the epileptiform activity that results from neonatal hypoxia

Microglia are described as the immune cells of the brain, their immune properties have been extensively studied since first described, however, their neural functions have only been explored over the last decade. Microglia have an important role in maintaining homeostasis in the central nervous system by surveying their surroundings to detect pathogens or damage cells. While these are the classical functions described for microglia, more recently their neural functions have been defined; they are critical to the maturation of neurons during embryonic and postnatal development, phagocytic microglia remove excess synapses during development, a process called synaptic pruning, which is important to overall neural maturation. Furthermore, microglia can respond to neuronal activity and, together with astrocytes, can regulate neural activity, contributing to the equilibrium between excitation and inhibition through a feedback loop. Hypoxia at birth is a serious neurological condition that disrupts normal brain function resulting in seizures and epilepsy later in life. Evidence has shown that microglia may contribute to this hyperexcitability after neonatal hypoxia. This review will summarize the existing data on the role of microglia in the pathogenesis of neonatal hypoxia and the plausible mechanisms that contribute to the development of hyperexcitability after hypoxia in neonates. This article is part of the Special Issue on "Microglia".

Single-Cell Transcriptomic Analyses of Brain Parenchyma in Patients With New-Onset Refractory Status Epilepticus (NORSE)

BACKGROUND AND OBJECTIVES

New-onset refractory status epilepticus (NORSE) occurs in previously healthy children or adults, often followed by refractory epilepsy and poor outcomes. The mechanisms that transform a normal brain into an epileptic one capable of seizing for prolonged periods despite treatment remain unclear. Nonetheless, several pieces of evidence suggest that immune dysregulation could contribute to hyperexcitability and modulate NORSE sequelae.

METHODS

We used single-nucleus RNA sequencing to delineate the composition and phenotypic states of the CNS of 4 patients with NORSE, to better understand the relationship between hyperexcitability and immune disturbances. We compared them with 4 patients with chronic temporal lobe epilepsy (TLE) and 2 controls with no known neurologic disorder.

RESULTS

Patients with NORSE and TLE exhibited a significantly higher proportion of excitatory neurons compared with controls, with no discernible difference in inhibitory GABAergic neurons. When examining the ratio between excitatory neurons and GABAergic neurons for each patient individually, we observed a higher ratio in patients with acute NORSE or TLE compared with controls. Furthermore, a negative correlation was found between the ratio of excitatory to GABAergic neurons and the proportion of GABAergic neurons. The ratio between excitatory neurons and GABAergic neurons correlated with the proportion of resident or infiltrating macrophages, suggesting the influence of microglial reactivity on neuronal excitability. Both patients with NORSE and TLE exhibited increased expression of genes associated with microglia activation, phagocytic activity, and NLRP3 inflammasome activation. However, patients with NORSE had decreased expression of genes related to the downregulation of the inflammatory response, potentially explaining the severity of their presentation. Microglial activation in patients with NORSE also correlated with astrocyte reactivity, possibly leading to higher degrees of demyelination.

DISCUSSION

Our study sheds light on the complex cellular dynamics in NORSE, revealing the potential roles of microglia, infiltrating macrophages, and astrocytes in hyperexcitability and demyelination, offering potential avenues for future research targeting the identified pathways.

Allopregnanolone and its antagonist modulate neuroinflammation and neurological impairment

Neuroinflammation accompanies several brain disorders, either as a secondary consequence or as a primary cause and may contribute importantly to disease pathogenesis. Neurosteroids which act as Positive Steroid Allosteric GABA-A receptor Modulators (Steroid-PAM) appear to modulate neuroinflammation and their levels in the brain may vary because of increased or decreased local production or import from the systemic circulation. The increased synthesis of steroid-PAMs is possibly due to increased expression of the mitochondrial cholesterol transporting protein (TSPO) in neuroinflammatory tissue, and reduced production may be due to changes in the enzymatic activity. Microglia and astrocytes play an important role in neuroinflammation, and their production of inflammatory mediators can be both activated and inhibited by steroid-PAMs and GABA. What is surprising is the finding that both allopregnanolone, a steroid-PAM, and golexanolone, a novel GABA-A receptor modulating steroid antagonist (GAMSA), can inhibit microglia and astrocyte activation and normalize their function. This review focuses on the role of steroid-PAMs in neuroinflammation and their importance in new therapeutic approaches to CNS and liver disease.

Second-line immunotherapy in new onset refractory status epilepticus

Several pieces of evidence suggest immune dysregulation could trigger the onset and modulate sequelae of new onset refractory status epilepticus (NORSE), including its subtype with prior fever known as febrile infection-related epilepsy syndrome (FIRES). Consensus-driven recommendations have been established to guide the initiation of first- and second-line immunotherapies in these patients. Here, we review the literature to date on second-line immunotherapy for NORSE/FIRES, presenting results from 28 case reports and series describing the use of anakinra, tocilizumab, or intrathecal dexamethasone in 75 patients with NORSE. Among them, 52 patients were managed with anakinra, 21 with tocilizumab, and eight with intrathecal dexamethasone. Most had elevated serum or cerebrospinal fluid cytokine levels at treatment initiation. Treatments were predominantly initiated during the acute phase of the disease (92%) and resulted, within the first 2 weeks, in seizure control for up to 73% of patients with anakinra, 70% with tocilizumab, and 50% with intrathecal dexamethasone. Cytokine levels decreased after treatment for most patients. Anakinra and intrathecal dexamethasone were mainly initiated in children with FIRES, whereas tocilizumab was more frequently prescribed for adults, with or without a prior febrile infection. There was no clear correlation between the response to treatment and the time to initiate the treatment. Most patients experienced long-term disability and drug-resistant post-NORSE epilepsy. Initiation of second-line immunotherapies during status epilepticus (SE) had no clear effect on the emergence of post-NORSE epilepsy or long-term functional outcomes. In a small number of cases, the initiation of anakinra or tocilizumab several years after SE onset resulted in a reduction of seizure frequency for 67% of patients. These data highlight the potential utility of anakinra, tocilizumab, and intrathecal dexamethasone in patients with NORSE. There continues to be interest in the utilization of early cytokine measurements to guide treatment selection and response. Prospective studies are necessary to understand the role of early immunomodulation and its associations with epilepsy and functional outcomes.

Neuroactive Steroids, Toll-like Receptors, and Neuroimmune Regulation: Insights into Their Impact on Neuropsychiatric Disorders

Pregnane neuroactive steroids, notably allopregnanolone and pregnenolone, exhibit efficacy in mitigating inflammatory signals triggered by toll-like receptor (TLR) activation, thus attenuating the production of inflammatory factors. Clinical studies highlight their therapeutic potential, particularly in conditions like postpartum depression (PPD), where the FDA-approved compound brexanolone, an intravenous formulation of allopregnanolone, effectively suppresses TLR-mediated inflammatory pathways, predicting symptom improvement. Additionally, pregnane neurosteroids exhibit trophic and anti-inflammatory properties, stimulating the production of vital trophic proteins and anti-inflammatory factors. Androstane neuroactive steroids, including estrogens and androgens, along with dehydroepiandrosterone (DHEA), display diverse effects on TLR expression and activation. Notably, androstenediol (ADIOL), an androstane neurosteroid, emerges as a potent anti-inflammatory agent, promising for therapeutic interventions. The dysregulation of immune responses via TLR signaling alongside reduced levels of endogenous neurosteroids significantly contributes to symptom severity across various neuropsychiatric disorders. Neuroactive steroids, such as allopregnanolone, demonstrate efficacy in alleviating symptoms of various neuropsychiatric disorders and modulating neuroimmune responses, offering potential intervention avenues. This review emphasizes the significant therapeutic potential of neuroactive steroids in modulating TLR signaling pathways, particularly in addressing inflammatory processes associated with neuropsychiatric disorders. It advances our understanding of the complex interplay between neuroactive steroids and immune responses, paving the way for personalized treatment strategies tailored to individual needs and providing insights for future research aimed at unraveling the intricacies of neuropsychiatric disorders.

Microglial P2Y6 calcium signaling promotes phagocytosis and shapes neuroimmune responses in epileptogenesis

Microglial calcium signaling is rare in a baseline state but strongly engaged during early epilepsy development. The mechanism(s) governing microglial calcium signaling are not known. By developing an in vivo uridine diphosphate (UDP) fluorescent sensor, GRABUDP1.0, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP can signal through the microglial-enriched P2Y6 receptor to increase calcium activity during epileptogenesis. P2Y6 calcium activity is associated with lysosome biogenesis and enhanced production of NF-κB-related cytokines. In the hippocampus, knockout of the P2Y6 receptor prevents microglia from fully engulfing neurons. Attenuating microglial calcium signaling through calcium extruder ("CalEx") expression recapitulates multiple features of P2Y6 knockout, including reduced lysosome biogenesis and phagocytic interactions. Ultimately, P2Y6 knockout mice retain more CA3 neurons and better cognitive task performance during epileptogenesis. Our results demonstrate that P2Y6 signaling impacts multiple aspects of myeloid cell immune function during epileptogenesis.

Integrated analysis of circRNA- related ceRNA network targeting neuroinflammation in medial temporal lobe epilepsy

BACKGROUND

medial temporal lobe epilepsy (mTLE) is among the most common types of temporal lobe epilepsy (TLE) ，it is generally resistant to drug treatment, which significantly impacts the quality of life and treatment. Research on novel therapeutic approaches for mTLE has become a current focus. Our study aims to construct and analyze a competing endogenous RNA (ceRNA) network that targets neuroinflammation using publicly available data, which may offer a novel therapeutic approach for mTLE.

METHODS

we utilized the R package to analyze GSE186334 downloaded from Gene Expression Omnibus database, subsequently constructing and identifying hub network within the ceRNA network using public databases. Lastly, we validated the expressions and interactions of some nodes within the hub ceRNA network in Sombati cell model.

RESULTS

our transcriptome analysis identified 649 differentially expressed (DE) mRNAs (273 up-regulated, 376 down-regulated) and 36 DE circRNAs (11 up-regulated, 25 down-regulated) among mTLE patients. A total of 23 candidate DE mRNAs associated with neuroinflammation were screened, and two ceRNA networks were constructed. A hub network was further screened which included 3 mRNAs, 22 miRNAs, and 11 circRNAs. Finally, we confirmed the hsa-miR-149-5p is crucial in the regulatory effect of hsa_circ_0005145 on IL - 1α in the hub network.

CONCLUSIONS

In summary, our study identified a hub ceRNA network and validated a potential circRNA-miRNA-mRNA axis targeting neuroinflammation. The results of our research may serve as a potential therapeutic target for mTLE.

Epilepsy and demyelination: Towards a bidirectional relationship

Demyelination stands out as a prominent feature in individuals with specific types of epilepsy. Concurrently, individuals with demyelinating diseases, such as multiple sclerosis (MS) are at a greater risk of developing epilepsy compared to non-MS individuals. These bidirectional connections raise the question of whether both pathological conditions share common pathogenic mechanisms. This review focuses on the reciprocal relationship between epilepsy and demyelination diseases. We commence with an overview of the neurological basis of epilepsy and demyelination diseases, followed by an exploration of how our comprehension of these two disorders has evolved in tandem. Additionally, we discuss the potential pathogenic mechanisms contributing to the interactive relationship between these two diseases. A more nuanced understanding of the interplay between epilepsy and demyelination diseases has the potential to unveiling the molecular intricacies of their pathological relationships, paving the way for innovative directions in future clinical management and treatment strategies for these diseases.

Proposed mechanisms of tau: relationships to traumatic brain injury, Alzheimer's disease, and epilepsy

Traumatic brain injury (TBI), Alzheimer's disease (AD), and epilepsy share proposed mechanisms of injury, including neuronal excitotoxicity, cascade signaling, and activation of protein biomarkers such as tau. Although tau is typically present intracellularly, in tauopathies, phosphorylated (p-) and hyper-phosphorylated (hp-) tau are released extracellularly, the latter leading to decreased neuronal stability and neurofibrillary tangles (NFTs). Tau cleavage at particular sites increases susceptibility to hyper-phosphorylation, NFT formation, and eventual cell death. The relationship between tau and inflammation, however, is unknown. In this review, we present evidence for an imbalanced endoplasmic reticulum (ER) stress response and inflammatory signaling pathways resulting in atypical p-tau, hp-tau and NFT formation. Further, we propose tau as a biomarker for neuronal injury severity in TBI, AD, and epilepsy. We present a hypothesis of tau phosphorylation as an initial acute neuroprotective response to seizures/TBI. However, if the underlying seizure pathology or TBI recurrence is not effectively treated, and the pathway becomes chronically activated, we propose a "tipping point" hypothesis that identifies a transition of tau phosphorylation from neuroprotective to injurious. We outline the role of amyloid beta (Aβ) as a "last ditch effort" to revert the cell to programmed death signaling, that, when fails, transitions the mechanism from injurious to neurodegenerative. Lastly, we discuss targets along these pathways for therapeutic intervention in AD, TBI, and epilepsy.

Mechanisms of microRNA-132 in central neurodegenerative diseases: A comprehensive review

MicroRNA-132 (miR-132) is a highly conserved molecule that plays a crucial regulatory role in central nervous system (CNS) disorders. The expression levels of miR-132 exhibit variability in various neurological disorders and have been closely linked to disease onset and progression. The expression level of miR-132 in the CNS is regulated by a diverse range of stimuli and signaling pathways, including neuronal migration and integration, dendritic outgrowth, and complexity, synaptogenesis, synaptic plasticity, as well as inflammation and apoptosis activation. The aberrant expression of miR-132 in various central neurodegenerative diseases has garnered widespread attention. Clinical studies have revealed altered miR-132 expression levels in both chronic and acute CNS diseases, positioning miR-132 as a potential biomarker or therapeutic target. An in-depth exploration of miR-132 holds the promise of enhancing our understanding of the mechanisms underlying CNS diseases, thereby offering novel insights and strategies for disease diagnosis and treatment. It is anticipated that this review will assist researchers in recognizing the potential value of miR-132 and in generating innovative ideas for clinical trials related to CNS degenerative diseases.

Progress in TLE treatment from 2003 to 2023: scientific measurement and visual analysis based on CiteSpace

Objective

Temporal lobe epilepsy (TLE) is the most common cause of drug-resistant epilepsy and can be treated surgically to control seizures. In this study, we analyzed the relevant research literature in the field of temporal lobe epilepsy (TLE) treatment to understand the background, hotspots, and trends in TLE treatment research.

Methods

We discussed the trend, frontier, and hotspot of scientific output in TLE treatment research in the world in the last 20 years by searching the core collection of the Web of Science database. Excel and CiteSpace software were used to analyze the basic data of the literature.

Result

We identified a total of 2,051 publications on TLE treatment from 75 countries between 2003 and 2023. We found that the publication rate was generally increasing. The United States was the most publishing country; among the research institutions on TLE treatment, the University of California system published the most relevant literature and collaborated the most with other institutions. The co-citation of literature, keyword co-occurrence, and its clustering analysis showed that the early studies focused on open surgical treatment, mainly by lobectomy. In recent years, the attention given to stereotactic, microsurgery, and other surgical techniques has gradually increased, and the burst analysis indicated that new research hotspots may appear in the future in the areas of improved surgical procedures and mechanism research.

Microglial P2Y6 calcium signaling promotes phagocytosis and shapes neuroimmune responses in epileptogenesis

Microglial calcium signaling is rare in a baseline state but shows strong engagement during early epilepsy development. The mechanism and purpose behind microglial calcium signaling is not known. By developing an in vivo UDP fluorescent sensor, GRABUDP1.0, we discovered that UDP release is a conserved response to seizures and excitotoxicity across brain regions. UDP signals to the microglial P2Y6 receptor for broad increases in calcium signaling during epileptogenesis. UDP-P2Y6 signaling is necessary for lysosome upregulation across limbic brain regions and enhances production of pro-inflammatory cytokines-TNFα and IL-1β. Failures in lysosome upregulation, observed in P2Y6 KO mice, can also be phenocopied by attenuating microglial calcium signaling in Calcium Extruder ("CalEx") mice. In the hippocampus, only microglia with P2Y6 expression can perform full neuronal engulfment, which substantially reduces CA3 neuron survival and impairs cognition. Our results demonstrate that calcium activity, driven by UDP-P2Y6 signaling, is a signature of phagocytic and pro-inflammatory function in microglia during epileptogenesis.

Zinc and Central Nervous System Disorders

Zinc (Zn²⁺) is the second most abundant necessary trace element in the human body, exerting a critical role in many physiological processes such as cellular proliferation, transcription, apoptosis, growth, immunity, and wound healing. It is an essential catalyst ion for many enzymes and transcription factors. The maintenance of Zn²⁺ homeostasis is essential for the central nervous system, in which Zn²⁺ is abundantly distributed and accumulates in presynaptic vesicles. Synaptic Zn²⁺ is necessary for neural transmission, playing a pivotal role in neurogenesis, cognition, memory, and learning. Emerging data suggest that disruption of Zn²⁺ homeostasis is associated with several central nervous system disorders including Alzheimer's disease, depression, Parkinson's disease, multiple sclerosis, schizophrenia, epilepsy, and traumatic brain injury. Here, we reviewed the correlation between Zn²⁺ and these central nervous system disorders. The potential mechanisms were also included. We hope that this review can provide new clues for the prevention and treatment of nervous system disorders.

1400 W, a selective inducible nitric oxide synthase inhibitor, mitigates early neuroinflammation and nitrooxidative stress in diisopropylfluorophosphate-induced short-term neurotoxicity rat model

Organophosphate nerve agent (OPNA) exposure induces acute and long-term neurological deficits. OPNA exposure at sub-lethal concentrations induces irreversible inhibition of acetylcholinesterase and cholinergic toxidrome and develops status epilepticus (SE). Persistent seizures have been associated with increased production of ROS/RNS, neuroinflammation, and neurodegeneration. A total of 1400W is a novel small molecule, which irreversibly inhibits inducible nitric oxide synthase (iNOS) and has been shown to effectively reduce ROS/RNS generation. In this study, we investigated the effects of 1400W treatment for a week or two weeks at 10 mg/kg or 15 mg/kg per day in the rat diisopropylfluorophosphate (DFP) model. 1400W significantly reduced the number of microglia, astroglia, and NeuN+FJB positive cells compared to the vehicle in different regions of the brain. 1400W also significantly reduced nitrooxidative stress markers and proinflammatory cytokines in the serum. However, neither of the two concentrations of 1400W for two weeks of treatment had any significant effect on epileptiform spike rate and spontaneous seizures during the treatment period in mixed sex cohorts, males, or females. No significant sex differences were found in response to DFP exposure or 1400W treatment. In conclusion, 1400W treatment at 15 mg/kg per day for two weeks was more effective in significantly reducing DFP-induced nitrooxidative stress, neuroinflammatory and neurodegenerative changes.

Cytokines in New-Onset Refractory Status Epilepticus Predict Outcomes

OBJECTIVE

The objective of this study was to investigate inflammation using cerebrospinal fluid (CSF) and serum cytokines/chemokines in patients with new-onset refractory status epilepticus (NORSE) to better understand the pathophysiology of NORSE and its consequences.

METHODS

Patients with NORSE (n = 61, including n = 51 cryptogenic), including its subtype with prior fever known as febrile infection-related epilepsy syndrome (FIRES), were compared with patients with other refractory status epilepticus (RSE; n = 37), and control patients without SE (n = 52). We measured 12 cytokines/chemokines in serum or CSF samples using multiplexed fluorescent bead-based immunoassay detection. Cytokine levels were compared between patients with and without SE, and between the 51 patients with cryptogenic NORSE (cNORSE) and the 47 patients with a known-etiology RSE (NORSE n = 10, other RSE n = 37), and correlated with outcomes.

RESULTS

A significant increase of IL-6, TNF-α, CXCL8/IL-8, CCL2, MIP-1α, and IL-12p70 pro-inflammatory cytokines/chemokines was observed in patients with SE compared with patients without SE, in serum and CSF. Serum innate immunity pro-inflammatory cytokines/chemokines (CXCL8, CCL2, and MIP-1α) were significantly higher in patients with cNORSE compared to non-cryptogenic RSE. Patients with NORSE with elevated innate immunity serum and CSF cytokine/chemokine levels had worse outcomes at discharge and at several months after the SE ended.

INTERPRETATION

We identified significant differences in innate immunity serum and CSF cytokine/chemokine profiles between patients with cNORSE and non-cryptogenic RSE. The elevation of innate immunity pro-inflammatory cytokines in patients with NORSE correlated with worse short- and long-term outcomes. These findings highlight the involvement of innate immunity-related inflammation, including peripherally, and possibly of neutrophil-related immunity in cNORSE pathogenesis and suggest the importance of utilizing specific anti-inflammatory interventions. ANN NEUROL 2023.

TGF-β Activated Kinase 1 (TAK1) Is Activated in Microglia After Experimental Epilepsy and Contributes to Epileptogenesis

Increasing evidence suggests that inflammation promotes epileptogenesis. TAK1 is a central enzyme in the upstream pathway of NF-κB and is known to play a central role in promoting neuroinflammation in neurodegenerative diseases. Here, we investigated the cellular role of TAK1 in experimental epilepsy. C57Bl6 and transgenic mice with inducible and microglia-specific deletion of Tak1 (Cx3cr1^CreER:Tak1^fl/fl) were subjected to the unilateral intracortical kainate mouse model of temporal lobe epilepsy (TLE). Immunohistochemical staining was performed to quantify different cell populations. The epileptic activity was monitored by continuous telemetric electroencephalogram (EEG) recordings over a period of 4 weeks. The results show that TAK1 was activated predominantly in microglia at an early stage of kainate-induced epileptogenesis. Tak1 deletion in microglia resulted in reduced hippocampal reactive microgliosis and a significant decrease in chronic epileptic activity. Overall, our data suggest that TAK1-dependent microglial activation contributes to the pathogenesis of chronic epilepsy.

The JAK-STAT Signaling Pathway in Epilepsy

Epilepsy is defined as spontaneous recurrent seizures in the brain. There is increasing evidence that inflammatory mediators and immune cells are involved in epileptic seizures. As more research is done on inflammatory factors and immune cells in epilepsy, new targets for the treatment of epilepsy will be revealed. The Janus kinase-signal transducer and transcriptional activator (JAKSTAT) signaling pathway is strongly associated with many immune and inflammatory diseases, At present, more and more studies have found that the JAK-STAT pathway is involved in the development and development of epilepsy, indicating the JAK-STAT pathway's potential promise as a target in epilepsy treatment. In this review, we discuss the composition, activation, and regulation of the JAK-STAT pathway and the relationship between the JAK-STAT pathway and epilepsy. In addition, we summarize the common clinical inhibitors of JAK and STAT that we would expect to be used in epilepsy treatment in the future.

Chronic stress but not acute stress decreases the seizure threshold in PTZ-induced seizure in mice: role of inflammatory response and oxidative stress

Seizure is paroxysmal abnormal electrical discharges in the cerebral cortex. Inflammatory pathways and oxidative stress are involved in the pathophysiology of seizures. Stress can induce an oxidative stress state and increase the production of inflammatory mediators in the brain. We investigated the effects of acute and chronic stresses on the seizure threshold in pentylenetetrazol (PTZ)-induced seizures in mice, considering oxidative stress and inflammatory mediators in the prefrontal cortex. In this study, 30 male Naval Medical Research Institute (NMRI) mice were divided into 3 groups, including acute stress, chronic stress, and control groups. PTZ was used for the induction of seizures. The gene expression of inflammatory markers (IL-1β, TNF-α, NLRP3, and iNOS), malondialdehyde (MDA) level, nitrite level, and total antioxidant capacity (TAC) were assessed in the prefrontal cortex and serum. Our results showed that stress could increase the expression of inflammatory cytokines genes and oxidative stress in the prefrontal cortex of the brain and serum following PTZ-induced seizures, which is associated with increased seizure sensitivity and decreased the seizure threshold. The effects of chronic stress were much more significant than acute stress. We concluded that the effects of chronic stress on seizure sensitivity and enhancement of neuroinflammation and oxidative stress are much greater than acute stress.

Hippocampal Cytokine Release in Experimental Epileptogenesis—A Longitudinal In Vivo Microdialysis Study

Background: Inflammation, particularly cytokine release, contributes to epileptogenesis by influencing the cerebral tissue remodeling and neuronal excitability that occurs after a precipitating epileptogenic insult. While several cytokines have been explored in this process, release kinetics are less well investigated. Determining the time course of cytokine release in the epileptogenic zone is necessary for precisely timed preventive or therapeutic anti-inflammatory interventions. Methods: Hippocampal extracellular levels of six cytokines and chemokines (IL-1β, IL-6, IL-10, CCL2, CCL3, and CCL5) were quantified at various time points during epileptogenesis in a rat model of mesial temporal lobe epilepsy with hippocampal sclerosis (mTLE-HS) using microdialysis (MD). Results: The analysis of microdialysates demonstrated consistent elevation at all time points during epileptogenesis for IL-1β and IL-10. IL-10 release was maximal on day 1, IL-1β release peaked at day 8. No correlation between local hippocampal IL-1β concentrations and IL-1β blood levels was found. Conclusion: The release kinetics of IL-1β are consistent with its established pro-epileptogenic properties, while the kinetics of IL-10 suggest a counter-regulatory effect. This proof-of-concept study demonstrates the feasibility of intraindividual longitudinal monitoring of hippocampal molecular inflammatory processes via repetitive MD over several weeks and sheds light on the kinetics of hippocampal cytokine release during epileptogenesis.

Molecular Mechanisms in the Genesis of Seizures and Epilepsy Associated With Viral Infection

Seizures are a common presenting symptom during viral infections of the central nervous system (CNS) and can occur during the initial phase of infection ("early" or acute symptomatic seizures), after recovery ("late" or spontaneous seizures, indicating the development of acquired epilepsy), or both. The development of acute and delayed seizures may have shared as well as unique pathogenic mechanisms and prognostic implications. Based on an extensive review of the literature, we present an overview of viruses that are associated with early and late seizures in humans. We then describe potential pathophysiologic mechanisms underlying ictogenesis and epileptogenesis, including routes of neuroinvasion, viral control and clearance, systemic inflammation, alterations of the blood-brain barrier, neuroinflammation, and inflammation-induced molecular reorganization of synapses and neural circuits. We provide clinical and animal model findings to highlight commonalities and differences in these processes across various neurotropic or neuropathogenic viruses, including herpesviruses, SARS-CoV-2, flaviviruses, and picornaviruses. In addition, we extensively review the literature regarding Theiler's murine encephalomyelitis virus (TMEV). This picornavirus, although not pathogenic for humans, is possibly the best-characterized model for understanding the molecular mechanisms that drive seizures, epilepsy, and hippocampal damage during viral infection. An enhanced understanding of these mechanisms derived from the TMEV model may lead to novel therapeutic interventions that interfere with ictogenesis and epileptogenesis, even within non-infectious contexts.

Anti-Epileptic Effect of Crocin on Experimental Temporal Lobe Epilepsy in Mice

Temporal lobe epilepsy (TLE) is a common kind of refractory epilepsy. More than 30% TLE patients were multi-drug resistant. Some patients may even develop into status epilepticus (SE) because of failing to control seizures. Thus, one of the avid goals for anti-epileptic drug development is to discover novel potential compounds to treat TLE or even SE. Crocin, an effective component of Crocus sativus L., has been applied in several epileptogenic models to test its anti-epileptic effect. However, it is still controversial and its effect on TLE remains unclear. Therefore, we investigated the effects of crocin on epileptogenesis, generalized seizures (GS) in hippocampal rapid electrical kindling model as well as SE and spotaneous recurrent seizure (SRS) in pilocarpine-induced TLE model in ICR mice in this study. The results showed that seizure stages and cumulative afterdischarge duration were significantly depressed by crocin (20 and 50 mg/kg) during hippocampal rapid kindling acquisition. And crocin (100 mg/kg) significantly reduced the incidence of GS and average seizure stages in fully kindled animals. In pilocarpine-induced TLE model, the latency of SE was significantly prolonged and the mortality of SE was significantly decreased by crocin (100 mg/kg), which can also significantly suppress the number of SRS. The underlying mechanism of crocin may be involved in the protection of neurons, the decrease of tumor necrosis factor-α in the hippocampus and the increase of brain derived neurotrophic factor in the cortex. In conclusion, crocin may be a potential and promising anti-epileptic compound for treatment of TLE.

The Function of NF-Kappa B During Epilepsy, a Potential Therapeutic Target

The transcriptional regulator nuclear factor kappa B (NF-κB) modulates cellular biological activity by binding to promoter regions in the nucleus and transcribing various protein-coding genes. The NF-κB pathway plays a major role in the expressing genes related to inflammation, including chemokines, interleukins, and tumor necrosis factor. It also transcribes genes that can promote neuronal survival or apoptosis. Epilepsy is one of the most common brain disorders and it not only causes death worldwide but also affects the day-to-day life of affected individuals. While epilepsy has diverse treatment options, there remain patients who are not sensitive to the existing treatment methods. Recent studies have implicated the critical role of NF-κB in epilepsy. It is upregulated in neurons, glial cells, and endothelial cells, due to neuronal loss, glial cell proliferation, blood-brain barrier dysfunction, and hippocampal sclerosis through the glutamate and γ-aminobutyric acid imbalance, ion concentration changes, and other mechanisms. In this review, we summarize the functional changes caused by the upregulation of NF-κB in the central nervous system during different periods after seizures. This review is the first to deconvolute the complicated functions of NF-κB, and speculate that the regulation of NF-κB can be a safe and effective treatment strategy for epilepsy.

Occurrence of early epilepsy in children with traumatic brain injury: a retrospective study

BACKGROUND

Early post-traumatic seizures (EPTS) refer to epileptic seizures occurring within one week after brain injury. This study aimed to define the risk factors of EPTS and the protective factors that could prevent its occurrence.

METHODS

This is a single-center retrospective study in the PICU, Beijing Children's Hospital. Patients diagnosed with traumatic brain injury (TBI), admitted with and without EPTS between January 2016 and December 2020 were included in the study.

RESULTS

We included 108 patients diagnosed with TBI. The overall EPTS incidence was 33.98% (35/108). The correlation between EPTS and depressed fractures is positive (P = 0.023). Positive correlations between EPTS and intracranial hemorrhage and subarachnoid hemorrhage had been established (P = 0.011and P = 0.004, respectively). The detection rates of EPTS in the electroencephalogram (EEG) monitoring was 80.00%. There was a significant difference in the EEG monitoring rate between the two groups (P = 0.041). Forty-one (37.86%, 41/108) post-neurosurgical patients were treated with prophylactic antiepileptic drugs (AEDs), and eight (19.51%, 8/41) still had seizures. No statistical significance was noted between the two groups in terms of prophylactic AEDs use (P = 0.519). Logistic regression analysis revealed that open craniocerebral injury and fever on admission were risk factors for EPTS, whereas, surgical intervention and use of hypertonic saline were associated with not developing EPTS.

CONCLUSIONS

Breakthrough EPTS occurred after severe TBI in 33.98% of pediatric cases in our cohort. This is a higher seizure incidence than that reported previously. Patients with fever on admission and open craniocerebral injuries are more likely to develop EPTS.

Neuroinflammation and Proinflammatory Cytokines in Epileptogenesis

Increasing evidence corroborates the fundamental role of neuroinflammation in the development of epilepsy. Proinflammatory cytokines (PICs) are crucial contributors to the inflammatory reactions in the brain. It is evidenced that epileptic seizures are associated with elevated levels of PICs, particularly interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α), which underscores the impact of neuroinflammation and PICs on hyperexcitability of the brain and epileptogenesis. Since the pathophysiology of epilepsy is unknown, determining the possible roles of PICs in epileptogenesis could facilitate unraveling the pathophysiology of epilepsy. About one-third of epileptic patients are drug-resistant, and existing treatments only resolve symptoms and do not inhibit epileptogenesis; thus, treatment of epilepsy is still challenging. Accordingly, understanding the function of PICs in epilepsy could provide us with promising targets for the treatment of epilepsy, especially drug-resistant type. In this review, we outline the role of neuroinflammation and its primary mediators, including IL-1β, IL-1α, IL-6, IL-17, IL-18, TNF-α, and interferon-γ (IFN-γ) in the pathophysiology of epilepsy. Furthermore, we discuss the potential therapeutic targeting of PICs and cytokine receptors in the treatment of epilepsy.

Therapeutic effect of acute and chronic use of different doses of vitamin D3 on seizure responses and cognitive impairments induced by pentylenetetrazole in immature male rats

Objective(s):

This study aimed to evaluate the effects of acute and chronic intake of different doses of vitamin D3 on seizure responses and cognitive impairment induced by pentylenetetrazole (PTZ) in immature male rats.

Materials and Methods:

Sixty-six immature male NMRI rats were divided into control (10), epileptic (10), and treatment groups (46). The stage 5 latency (S5L) and stage 5 duration (S5D) were assessed along with the shuttle box test. Levels of antioxidant enzymes and inflammatory factors along with genes involved in inflammation, oxidative damage, apoptosis, and mTORc1 were measured in the hippocampus tissue of the brain of controlled and treated rats. Serum levels of parathyroid hormone (PTH), vitamin D, calcium, and phosphorus were also assessed.

Results:

The results showed that the ability to learn, memory consolidation, and memory retention in epileptic rats were reduced. In addition, S5D increased and S5L decreased in epileptic rats, while being effectively ameliorated by chronic and acute vitamin D intake. The results showed that vitamin D in different doses acutely and chronically decreased the levels of oxidative and inflammatory biomarkers in hippocampus tissue and inhibited the expression of genes involved in inflammation, oxidative damage, apoptosis, and mTORc1 in the hippocampus tissue of epileptic rats.

Conclusion:

The results showed that vitamin D in different doses acutely and chronically could improve cognitive impairments and convulsive responses in epileptic rats by improving neurotransmission, inflammation, apoptosis, and oxidative damage.

Past, present and future of therapeutic strategies against amyloid-β peptides in Alzheimer's disease: a systematic review

Alzheimer's disease (AD) is the most prevalent neurodegenerative disease in ageing, affecting around 46 million people worldwide but few treatments are currently available. The etiology of AD is still puzzling, and new drugs development and clinical trials have high failure rates. Urgent outline of an integral (multi-target) and effective treatment of AD is needed. Accumulation of amyloid-β (Aβ) peptides is considered one of the fundamental neuropathological pillars of the disease, and its dyshomeostasis has shown a crucial role in AD onset. Therefore, many amyloid-targeted therapies have been investigated. Here, we will systematically review recent (from 2014) investigational, follow-up and review studies focused on anti-amyloid strategies to summarize and analyze their current clinical potential. Combination of anti-Aβ therapies with new developing early detection biomarkers and other therapeutic agents acting on early functional AD changes will be highlighted in this review. Near-term approval seems likely for several drugs acting against Aβ, with recent FDA approval of a monoclonal anti-Aβ oligomers antibody -aducanumab- raising hopes and controversies. We conclude that, development of oligomer-epitope specific Aβ treatment and implementation of multiple improved biomarkers and risk prediction methods allowing early detection, together with therapies acting on other factors such as hyperexcitability in early AD, could be the key to slowing this global pandemic.

Effect of valproate and add-on levetiracetam on inflammatory biomarkers in children with epilepsy

BACKGROUND

Contemporary research indicates the role of neuroinflammation/inflammatory markers in epilepsy. In addition, comorbidities such as anxiety and poor health-related quality of life are vital concerns in clinical care of pediatric patients with epilepsy. This open-label, prospective, observational study evaluated the effect of valproate and add-on levetiracetam on serum levels of C-C motif ligand 2 (CCL2) and Interleukin-1 beta (IL-1β) in pediatric patients with epilepsy. We also studied effect of valproate and add-on levetiracetam on anxiety and health-related quality of life (HRQoL) in specified age subgroups.

METHODS

Children aged 1 to 12 years, diagnosed with epilepsy (generalized or focal seizures), treated with valproate (n = 40) and valproate with add-on levetiracetam (n = 40) were included. All patients were followed up for 16 weeks and assessed for changes in serum CCL2 and IL-1β levels. Spence Children Anxiety Scale short version (SCAS-S) and QOLCE-16 scales were used to measure anxiety and HRQoL, respectively, in specific age groups.

RESULTS

The serum CCL2 level decreased significantly (p < .001) from 327.95 ± 59.07 pg/ml to 207.02 ± 41.50 pg/ml in the valproate group and from 420.65 ± 83.72 pg/ml to 250.06 ± 46.05 pg/ml in the add-on levetiracetam group. Serum IL-1β level did not change significantly in both groups. Spence Children Anxiety Scale short version scores were decreased and QOLCE-16 scores were increased significantly (p < .001) in both valproate and add-on levetiracetam groups.

CONCLUSIONS

The results of our study suggest that valproate and levetiracetam led to decrease serum CCL2 levels without any change in serum IL-1β levels in children with epilepsy. Anti-inflammatory property of valproate and levetiracetam might underlie their antiepileptic effect and CCL2 could be a potential marker of drug efficacy in epilepsy. Also, valproate and levetiracetam reduced anxiety and improved quality of life in children with epilepsy in the age groups evaluated.

Sleep Disruption Worsens Seizures: Neuroinflammation as a Potential Mechanistic Link

Sleep disturbances, such as insomnia, obstructive sleep apnea, and daytime sleepiness, are common in people diagnosed with epilepsy. These disturbances can be attributed to nocturnal seizures, psychosocial factors, and/or the use of anti-epileptic drugs with sleep-modifying side effects. Epilepsy patients with poor sleep quality have intensified seizure frequency and disease progression compared to their well-rested counterparts. A better understanding of the complex relationship between sleep and epilepsy is needed, since approximately 20% of seizures and more than 90% of sudden unexpected deaths in epilepsy occur during sleep. Emerging studies suggest that neuroinflammation, (e.g., the CNS immune response characterized by the change in expression of inflammatory mediators and glial activation) may be a potential link between sleep deprivation and seizures. Here, we review the mechanisms by which sleep deprivation induces neuroinflammation and propose that neuroinflammation synergizes with seizure activity to worsen neurodegeneration in the epileptic brain. Additionally, we highlight the relevance of sleep interventions, often overlooked by physicians, to manage seizures, prevent epilepsy-related mortality, and improve quality of life.

The Cross Talk between Underlying Mechanisms of Multiple Sclerosis and Epilepsy May Provide New Insights for More Efficient Therapies

Despite the significant differences in pathological background of neurodegenerative diseases, epileptic seizures are a comorbidity in many disorders such as Huntington disease (HD), Alzheimer's disease (AD), and multiple sclerosis (MS). Regarding the last one, specifically, it has been shown that the risk of developing epilepsy is three to six times higher in patients with MS compared to the general population. In this context, understanding the pathological processes underlying this connection will allow for the targeting of the common and shared pathological pathways involved in both conditions, which may provide a new avenue in the management of neurological disorders. This review provides an outlook of what is known so far about the bidirectional association between epilepsy and MS.

Role of glutamate excitotoxicity and glutamate transporter EAAT2 in epilepsy: Opportunities for novel therapeutics development

Epilepsy is a complex neurological syndrome characterized by seizures resulting from neuronal hyperexcitability and sudden and synchronized bursts of electrical discharges. Impaired astrocyte function that results in glutamate excitotoxicity has been recognized to play a key role in the pathogenesis of epilepsy. While there are 26 drugs marketed as anti-epileptic drugs no current treatments are disease modifying as they only suppress seizures rather than the development and progression of epilepsy. Excitatory amino acid transporters (EAATs) are critical for maintaining low extracellular glutamate concentrations and preventing excitotoxicity. When extracellular glutamate concentrations rise to abnormal levels, glutamate receptor overactivation and the subsequent excessive influx of calcium into the post-synaptic neuron can trigger cell death pathways. In this review we discuss targeting EAAT2, the predominant glutamate transporter in the CNS, as a promising approach for developing therapies for epilepsy. EAAT2 upregulation via transcriptional and translational regulation has proven successful in vivo in reducing spontaneous recurrent seizures and offering neuroprotective effects. Another approach to regulate EAAT2 activity is through positive allosteric modulation (PAM). Novel PAMs of EAAT2 have recently been identified and are under development, representing a promising approach for the advance of novel therapeutics for epilepsy.

Acute glucose fluctuation induces inflammation and neurons apoptosis in hippocampal tissues of diabetic rats

It is well-recognized that glycemic disorders are leading causes of diabetic complications and acute fluctuation of blood glucose and reported more likely being related to oxidative stress, vasculopathy, and other diabetic complications than continuous hyperglycemia in patients with diabetic and animal models. To explore the hypothesis that acute glucose fluctuation (GF) aggravates inflammatory lesions and neuron apoptosis in the hippocampus of diabetic rats. Twenty female GK rats were randomly allocated into a glucose fluctuating group (GK-GF) and a continuous hyperglycemia group (GK-CHG) and 10 age-matched female Wistar rats served as controls. GF was induced in the GK-GF group by injection with glucose and insulin at different periods of time per day for 6 weeks. Body weight was determined weekly. At the end of the study, blood hemoglobin A1c (HbA1c) and serum lipids were measured. Serum and hippocampus interleukin 1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α (TNF-α) were measured by enzyme-linked immunosorbent assay and real-time quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Hippocampus Bcl-2, Bax, Pten, fas, and myc were quantified by qRT-PCR and Western blot analysis and Mirror Water Maze (MWM) test was performed. We successfully established an animal model with daily GF and a control model with CHG using GK diabetic rats. The GF and CHG rats showed lower weight gain during the 6-week experimental period with no significant difference in the levels of serum lipids such as total triglyceride, total cholesterol, high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol compared with the control rats at the end of the study. Meanwhile, the GF and CHG rats showed higher blood HbA1c levels than that of control rats. MWM trainings tests detected that glucose disorders in GF and CHG rats tend to present longer latencies, more cross times and longer path length compared with those of the control rats, indicating impaired the hippocampus-regulated behavioral function such as spatial orientating and memory. Importantly, it was found that GF promoted the expression of TNF-α and IL-1β in the hippocampus of the GF rats while continuous hyperglycemia in CHG rats had little effect on that. Furthermore, both GF and CHG diabetic rats had abnormal expression of apoptosis-associated genes in the hippocampus compared with control Wistar rats and neurons apoptosis in GF rats appears to be more severe than CHG rats. Overall, this study confirmed that GF is a more critical factor that would promote the neuron apoptosis and induce inflammation in the hippocampus than continuous hyperglycemia in diabetic animals, which shed new light on the importance of monitoring and administration of blood glucose in the prevention and therapy for diabetes.

Neuroprotective Effect of Taurine against Cell Death, Glial Changes, and Neuronal Loss in the Cerebellum of Rats Exposed to Chronic-Recurrent Neuroinflammation Induced by LPS

The present study investigated the neuroprotective effect of taurine against the deleterious effects of chronic-recurrent neuroinflammation induced by LPS in the cerebellum of rats. Adult male Wistar rats were treated with taurine for 28 days. Taurine was administered at a dose of 30 or 100 mg/kg, by gavage. On days 7, 14, 21, and 28, the animals received LPS (250 μg/kg) intraperitoneally. The vehicle used was saline. The animals were divided into six groups: vehicle, taurine 30 mg/kg, taurine 100 mg/kg, LPS, LPS plus taurine 30 mg/kg, and LPS plus taurine 100 mg/kg. On day 29, the animals were euthanized, and the cerebellum was removed and prepared for immunofluorescence analysis using antibodies of GFAP, NeuN, CD11b, and cleaved caspase-3. LPS group showed a reduction in the immunoreactivity of GFAP in the arbor vitae and medullary center and of NeuN in the granular layer of the cerebellar cortex. LPS increased the immunoreactivity of CD11b in the arbor vitae and in the medullary center. Taurine protected against these effects induced by LPS in immunoreactivity of GFAP, NeuN, and CD11b, with the 100 mg/kg dose being the most effective. LPS induced an increase in the number of positive cleaved caspase-3 cells in the Purkinje cell layers, granular layer, arbor vitae, and medullary center. Taurine showed its antiapoptotic activity by reducing the cleaved caspase-3 cells in relation to the LPS group. Here, a potential neuroprotective role of taurine can be seen since this amino acid was effective in protecting the cerebellum of rats against cell death and changes in glial and neuronal cells in the face of chronic-recurrent neuroinflammation.

Chemistry, Pharmacology and Therapeutic Potential of Swertiamarin - A Promising Natural Lead for New Drug Discovery and Development

Swertiamarin, a seco-iridoid glycoside, is mainly found in Enicostemma littorale Blume (E. littorale) and exhibits therapeutic activities for various diseases. The present study aimed to provide a review of swertiamarin in terms of its phytochemistry, physicochemical properties, biosynthesis, pharmacology and therapeutic potential. Relevant literature was collected from several scientific databases, including PubMed, ScienceDirect, Scopus and Google Scholar, between 1990 and the present. This review included the distribution of swertiamarin in medicinal plants and its isolation, characterization, physicochemical properties and possible biosynthetic pathways. A comprehensive summary of the pharmacological activities, therapeutic potential and metabolic pathways of swertiamarin was also included after careful screening and tabulation. Based on the reported evidence, swertiamarin meets all five of Lipinski’s rules for drug-like properties. Thereafter, the physicochemical properties of swertiamarin were detailed and analyzed. A simple and rapid method for isolating swertiamarin from E. littorale has been described. The present review proposed that swertiamarin may be biosynthesized by the mevalonate or nonmevalonate pathways, followed by the seco-iridoid pathway. It has also been found that swertiamarin is a potent compound with diverse pharmacological activities, including hepatoprotective, analgesic, anti-inflammatory, antiarthritis, antidiabetic, antioxidant, neuroprotective and gastroprotective activities. The anticancer activity of swertiamarin against different cancer cell lines has been recently reported. The underlying mechanisms of all these pharmacological effects are diverse and seem to involve the regulation of different molecular targets, including growth factors, inflammatory cytokines, protein kinases, apoptosis-related proteins, receptors and enzymes. Swertiamarin also modulates the activity of several transcription factors, and their signaling pathways in various pathological conditions are also discussed. Moreover, we have highlighted the toxicity profile, pharmacokinetics and possible structural modifications of swertiamarin. The pharmacological activities and therapeutic potential of swertiamarin have been extensively investigated. However, more advanced studies are required including clinical trials and studies on the bioavailability, permeability and administration of safe doses to offer swertiamarin as a novel candidate for future drug development.

ATP and adenosine-Two players in the control of seizures and epilepsy development

Despite continuous advances in understanding the underlying pathogenesis of hyperexcitable networks and lowered seizure thresholds, the treatment of epilepsy remains a clinical challenge. Over one third of patients remain resistant to current pharmacological interventions. Moreover, even when effective in suppressing seizures, current medications are merely symptomatic without significantly altering the course of the disease. Much effort is therefore invested in identifying new treatments with novel mechanisms of action, effective in drug-refractory epilepsy patients, and with the potential to modify disease progression. Compelling evidence has demonstrated that the purines, ATP and adenosine, are key mediators of the epileptogenic process. Extracellular ATP concentrations increase dramatically under pathological conditions, where it functions as a ligand at a host of purinergic receptors. ATP, however, also forms a substrate pool for the production of adenosine, via the action of an array of extracellular ATP degrading enzymes. ATP and adenosine have assumed largely opposite roles in coupling neuronal excitability to energy homeostasis in the brain. This review integrates and critically discusses novel findings regarding how ATP and adenosine control seizures and the development of epilepsy. This includes purine receptor P1 and P2-dependent mechanisms, release and reuptake mechanisms, extracellular and intracellular purine metabolism, and emerging receptor-independent effects of purines. Finally, possible purine-based therapeutic strategies for seizure suppression and disease modification are discussed.

Sublayer- and cell-type-specific neurodegenerative transcriptional trajectories in hippocampal sclerosis

Hippocampal sclerosis, the major neuropathological hallmark of temporal lobe epilepsy, is characterized by different patterns of neuronal loss. The mechanisms of cell-type-specific vulnerability and their progression and histopathological classification remain controversial. Using single-cell electrophysiology in vivo and immediate-early gene expression, we reveal that superficial CA1 pyramidal neurons are overactive in epileptic rodents. Bulk tissue and single-nucleus expression profiling disclose sublayer-specific transcriptomic signatures and robust microglial pro-inflammatory responses. Transcripts regulating neuronal processes such as voltage channels, synaptic signaling, and cell adhesion are deregulated differently by epilepsy across sublayers, whereas neurodegenerative signatures primarily involve superficial cells. Pseudotime analysis of gene expression in single nuclei and in situ validation reveal separated trajectories from health to epilepsy across cell types and identify a subset of superficial cells undergoing a later stage in neurodegeneration. Our findings indicate that sublayer- and cell-type-specific changes associated with selective CA1 neuronal damage contribute to progression of hippocampal sclerosis.

Astrocyte and glutamate involvement in the pathogenesis of epilepsy in Alzheimer's disease

Alzheimer's disease (AD) can increase the risk of epilepsy by up to 10-fold compared to healthy age-matched controls. However, the pathological mechanisms that underlie this increased risk are poorly understood. Because disruption in brain glutamate homeostasis has been implicated in both AD and epilepsy, this might play a mechanistic role in the pathogenesis of epilepsy in AD. Prior to the formation of amyloid beta (Aβ) plaques, the brain can undergo pathological changes as a result of increased production of amyloid precursor protein (APP) and Aβ oligomers. Impairments in the glutamate uptake ability of astrocytes due to astrogliosis are hypothesized to be an early event occurring before Aβ plaque formation. Astrogliosis may increase the susceptibility to epileptogenesis of the brain via accumulation of extracellular glutamate and resulting excitotoxicity. Here we hypothesize that Aβ oligomers and proinflammatory cytokines can cause astrogliosis and accumulation of extracellular glutamate, which then contribute to the pathogenesis of epilepsy in AD. In this review article, we consider the evidence supporting a potential role of dysfunction of the glutamate-glutamine cycle and the astrocyte in the pathogenesis of epilepsy in AD.

Embelin ameliorates cognitive dysfunction and progression of kindling in pentylenetetrazol-induced kindling in mice by attenuating brain inflammation

OBJECTIVE

This study was conducted to evaluate the effect of embelin (EMB) on various epileptic models and related brain inflammation.

METHODS

Male Swiss albino mice were administered EMB (5, 10, and 20 mg/kg/p.o.) in acute and chronic study for 7 days and 35 days, respectively. Acute study included increasing current electroshock (ICES) and pentylenetetrazol (PTZ)-induced seizure test. Step-down latency (SDL) and forced swim test (FST) were performed to evaluate cognitive functions and depression-like behavior, respectively. Chronic study included PTZ-induced kindling. Levels of inflammatory biomarkers, namely interleukin-1 beta (IL-1β), interleukin-1 receptor antagonist (IL-1Ra), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α), were estimated in the hippocampus and cortex of the kindled brains by ELISA technique. Further, neurotransmitters (NTs), namely gamma aminobutyric acid (GABA), glutamate, and dopamine, were estimated by using validated liquid chromatography-mass spectrometry (LC-MS) method followed by ultra-high-performance liquid chromatography (UHPLC).

RESULTS

Embelin (EMB) treatment increased the seizure threshold to hind limb extension (HLE) in the ICES test and decreased the seizure scores in the kindling experiment. Significantly low levels of IL-1β, IL-1Ra, IL-6, and TNF-α were observed in the hippocampus of PTZ + EMB (10 and 20 mg/kg)-treated groups compared with PTZ+ vehicle-treated group. Significantly lower levels of IL-1Ra, IL-6, and TNF-α compared with PTZ+ vehicle-treated group were observed in the cortex of PTZ + EMB (10 and 20 mg/kg)-treated groups, while IL-1β levels were found to be significantly lower only in the cortex of PTZ + EMB (20 mg/kg)-treated group. Increased levels of dopamine and GABA and decreased levels of glutamate in both hippocampus and cortex were observed in EMB + PTZ-treated groups compared with vehicle + PTZ-treated group. Latency of step down was found to be increased and immobility time in FST was decreased in EMB + PTZ groups compared with vehicle + PTZ group.

CONCLUSION

Embelin suppressed epileptogenesis in the kindled mice via neurochemical modulation of neurotransmitters and inhibiting the inflammatory pathway. Further, EMB was also observed to be protecting the kindled animals from cognition and depression-like behavior.

The association between toll-like receptor 4 (TLR4) genotyping and the risk of epilepsy in children

Background

Epilepsy is one of the most widely recognized neurological disorders; unfortunately, twenty to thirty percent of patients do not get cured from epilepsy, despite many trials of antiepileptic drug (AED) therapy. Immunotherapy may be a viable treatment strategy in a subset of epileptic patients. The association between Toll-like receptor polymorphisms and epilepsy clarifies the role of the immune system in epilepsy and its response to the drug. Thus, this study will focus on the relation between TLR4 rs1927914, rs11536858, rs1927911SNPs, and epilepsy in an Egyptian case-control study to assess their link to antiepileptic drug response.

Results

According to TLR4 rs1927914, there is a significant association between the SNP and the development of epilepsy, as CC genotype is 15.3 times more at risk for developing epilepsy than TT genotype, and CT is 11.1 times more at risk for developing epilepsy than TT. Also, patients with CC genotypes are 6.3 times more at risk for developing primary epilepsy than TT genotype.

According to rs11536858, there is a significant association between cases and control groups, as AA genotypes are found to be more at risk for developing epilepsy than GG genotypes. Also, there is a statistically significant association between clonazepam resistance and rs11536858, as p value < 0.001* with the highest frequency of TT genotypes at 4.3%.

According to rs1927911, there are no significant results between the cases and the control groups or between drug-responsive and drug resistance.

Conclusion

Possible involvement of the Toll-like receptor clarifies the importance of innate immunity in initiating seizures and making neuronal hyperexcitability. In this work, multiple significant associations between TLR SNPs and epilepsy, epileptic phenotype, and drug-resistant epilepsy have been found. More studies with bigger sample sizes and different techniques with different SNPs are recommended to find the proper immunotherapy for epilepsy instead of the treatment by antiepileptic drugs.

Modulation of Brain Hyperexcitability: Potential New Therapeutic Approaches in Alzheimer's Disease

People with Alzheimer's disease (AD) have significantly higher rates of subclinical and overt epileptiform activity. In animal models, oligomeric Aβ amyloid is able to induce neuronal hyperexcitability even in the early phases of the disease. Such aberrant activity subsequently leads to downstream accumulation of toxic proteins, and ultimately to further neurodegeneration and neuronal silencing mediated by concomitant tau accumulation. Several neurotransmitters participate in the initial hyperexcitable state, with increased synaptic glutamatergic tone and decreased GABAergic inhibition. These changes appear to activate excitotoxic pathways and, ultimately, cause reduced long-term potentiation, increased long-term depression, and increased GABAergic inhibitory remodelling at the network level. Brain hyperexcitability has therefore been identified as a potential target for therapeutic interventions aimed at enhancing cognition, and, possibly, disease modification in the longer term. Clinical trials are ongoing to evaluate the potential efficacy in targeting hyperexcitability in AD, with levetiracetam showing some encouraging effects. Newer compounds and techniques, such as gene editing via viral vectors or brain stimulation, also show promise. Diagnostic challenges include identifying best biomarkers for measuring sub-clinical epileptiform discharges. Determining the timing of any intervention is critical and future trials will need to carefully stratify participants with respect to the phase of disease pathology.

Lrp4 in hippocampal astrocytes serves as a negative feedback factor in seizures

BACKGROUND

Epilepsy is characterized by the typical symptom of seizure, and anti-seizure medications are the main therapeutic method in clinical, but the effects of these therapy have not been satisfactory. To find a better treatment, it makes sense to further explore the regulatory mechanisms of seizures at genetic level. Lrp4 regionally expresses in mice hippocampus where is key to limbic epileptogenesis. It is well known that neurons release a high level of glutamate during seizures, and it has been reported that Lrp4 in astrocytes down-regulates glutamate released from neurons. However, it is still unclear whether there is a relationship between Lrp4 expression level and seizures, and whether Lrp4 plays a role in seizures.

RESULTS

We found that seizures induced by pilocarpine decreased Lrp4 expression level and increased miR-351-5p expression level in mice hippocampus. Glutamate reduced Lrp4 expression and enhanced miR-351-5p expression in cultured hippocampal astrocytes, and these effects can be partially attenuated by AP5. Furthermore, miR-351-5p inhibitor lessened the reduction of Lrp4 expression in glutamate treated hippocampal astrocytes. Local reduction of Lrp4 in hippocampus by sh Lrp4 lentivirus injection in hippocampus increased the threshold of seizures in pilocarpine or pentylenetetrazol (PTZ) injected mice.

CONCLUSIONS

These results indicated that high released glutamate induced by seizures down-regulated astrocytic Lrp4 through increasing miR-351-5p in hippocampal astrocytes via activating astrocytic NMDA receptor, and locally reduction of Lrp4 in hippocampus increased the threshold of seizures. Lrp4 in hippocampal astrocytes appears to serve as a negative feedback factor in seizures. This provides a new potential therapeutic target for seizures regulation.

Environmental regulation of the chloride transporter KCC2: switching inflammation off to switch the GABA on?

Chloride homeostasis, the main determinant factor for the dynamic tuning of GABAergic inhibition during development, has emerged as a key element altered in a wide variety of brain disorders. Accordingly, developmental disorders such as schizophrenia, Autism Spectrum Disorder, Down syndrome, epilepsy, and tuberous sclerosis complex (TSC) have been associated with alterations in the expression of genes codifying for either of the two cotransporters involved in the excitatory-to-inhibitory GABA switch, KCC2 and NKCC1. These alterations can result from environmental insults, including prenatal stress and maternal separation which share, as common molecular denominator, the elevation of pro-inflammatory cytokines. In this review we report and systemize recent research articles indicating that different perinatal environmental perturbations affect the expression of chloride transporters, delaying the developmental switch of GABA signaling, and that inflammatory cytokines, in particular interleukin 1β, may represent a key causal factor for this phenomenon. Based on literature data, we provide therefore a unifying conceptual framework, linking environmental hits with the excitatory-to-inhibitory GABA switch in the context of brain developmental disorders.

Quantitative proteomics of cerebrospinal fluid using tandem mass tags in dogs with recurrent epileptic seizures

This prospective study included four dog groups (group A: healthy dogs, groups B: dogs with idiopathic epilepsy under antiepileptic medication (AEM), C: idiopathic epilepsy dogs without AEM administration, D: dogs with structural epilepsy). The purpose of the study was to compare the proteomic profile among the four groups. Samples were analyzed by a quantitative Tandem Mass Tags approach using a Q-Exactive-Plus mass-spectrometer. Identification and relative quantification were performed using Proteome Discoverer, and data were analyzed using R. Gene ontology terms were analyzed based on Canis lupus familiaris database. Data are available via ProteomeXchange with identifier PXD018893. Eighteen proteins were statistically significant among the four groups (P < 0.05). MMP2 and EFEMP2 appeared down-regulated whereas HP and APO-A1 were up-regulated (groups B, D). CLEC3B and PEBP4 were up-regulated whereas APO-A1 was down-regulated (group C). IGLL1 was down-regulated (groups B, C) and up-regulated (group D). EFEMP2 was the only protein detected among the four groups and PEBP4 was significantly different among the epileptic dogs. Western blot and SPARCL immunoassay were used to quantify HP abundance change, validating proteomic analysis. Both, showed good correlation with HP levels identified through proteomic analysis (r = 0.712 and r = 0.703, respectively). SIGNIFICANCE: The proteomic analysis from CSF of dogs with epileptic seizures could reflect that MMP2, HP and APO-A1 may contribute to a blood-brain barrier disruption through the seizure-induced inflammatory process in the brain. MMP2 change may indicate the activation of protective mechanisms within the brain tissue. Antiepileptic medication could influence several cellular responses and alter the CSF proteome composition.

Locus Coeruleus Degeneration Induces Forebrain Vascular Pathology in a Transgenic Rat Model of Alzheimer's Disease

Noradrenergic locus coeruleus (LC) neuron loss is a significant feature of mild cognitive impairment and Alzheimer's disease (AD). The LC is the primary source of norepinephrine in the forebrain, where it modulates attention and memory in vulnerable cognitive regions such as prefrontal cortex (PFC) and hippocampus. Furthermore, LC-mediated norepinephrine signaling is thought to play a role in blood-brain barrier (BBB) maintenance and neurovascular coupling, suggesting that LC degeneration may impact the high comorbidity of cerebrovascular disease and AD. However, the extent to which LC projection system degeneration influences vascular pathology is not fully understood. To address this question in vivo, we stereotactically lesioned LC projection neurons innervating the PFC of six-month-old Tg344-19 AD rats using the noradrenergic immunotoxin, dopamine-β-hydroxylase IgG-saporin (DBH-sap), or an untargeted control IgG-saporin (IgG-sap). DBH-sap-lesioned animals performed significantly worse than IgG-sap animals on the Barnes maze task in measures of both spatial and working memory. DBH-sap-lesioned rats also displayed increased amyloid and inflammation pathology compared to IgG-sap controls. However, we also discovered prominent parenchymal albumin extravasation with DBH-sap lesions indicative of BBB breakdown. Moreover, microvessel wall-to-lumen ratios were increased in the PFC of DBH-sap compared to IgG-sap rats, suggesting that LC deafferentation results in vascular remodeling. Finally, we noted an early emergence of amyloid angiopathy in the DBH-sap-lesioned Tg344-19 AD rats. Taken together, these data indicate that LC projection system degeneration is a nexus lesion that compromises both vascular and neuronal function in cognitive brain areas during the prodromal stages of AD.

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.

Blood biomarkers predictive of epilepsy after an acute stroke event

OBJECTIVE

Blood biomarkers have not been widely investigated in poststroke epilepsy. In this study, we aimed to describe clinical factors and biomarkers present during acute stroke and analyze their association with the development of epilepsy at long term.

METHODS

A panel of 14 blood biomarkers was evaluated in patients with ischemic and hemorrhagic stroke. Biomarkers were normalized and standardized using Z-scores. Stroke and epilepsy-related variables were also assessed: stroke severity, determined by National Institutes of Health Stroke Scale (NIHSS) score, stroke type and cause, time from stroke to onset of late seizures, and type of seizure. Multiple Cox regression models were used to identify clinical variables and biomarkers independently associated with epilepsy.

RESULTS

From a cohort of 1115 patients, 895 patients were included. Mean ± standard deviation (SD) age was 72.0 ± 13.1 years, and 57.8% of patients were men. Fifty-one patients (5.7%) developed late seizures, with a median time to onset of 232 days (interquartile range [IQR] 86-491). NIHSS score ≥8 (P < .001, hazard ratio [HR] 4.013, 95% confidence interval [CI] 2.123-7.586) and a history of early onset seizures (P < .001, HR 4.038, 95% CI 1.802-9.045) were factors independently associated with a risk of developing epilepsy. Independent blood biomarkers predictive of epilepsy were high endostatin levels >1.203 (P = .046, HR 4.300, 95% CI 1.028-17.996) and low levels of heat shock 70 kDa protein-8 (Hsc70) <2.496 (P = .006, HR 3.795, 95% CI 1.476-9.760) and S100B <1.364 (P = .001, HR 2.955, 95% CI 1.534-5.491). The risk of epilepsy when these biomarkers were combined increased to 17%. The area under the receiver-operating characteristic (ROC) curve of the predictive model was stronger when clinical variables were combined with blood biomarkers (74.3%, 95% CI 65.2%-83.3%) than when they were used alone (68.9%, 95% CI 60.3%-77.6%).

SIGNIFICANCE

Downregulated S100B and Hsc70 and upregulated endostatin may assist in prediction of poststroke epilepsy and may provide additional information to clinical risk factors. In addition, these data are hypothesis-generating for the epileptogenic process.

The Roles of Autoimmunity and Biotoxicosis in Sick Building Syndrome as a "Starting Point" for Irreversible Dampness and Mold Hypersensitivity Syndrome

BACKGROUND

The terminology of "sick building syndrome" (SBS), meaning that a person may feel sick in a certain building, but when leaving the building, the symptoms will reverse, is imprecise. Many different environmental hazards may cause the feeling of sickness, such as high indoor air velocity, elevated noise, low or high humidity, vapors or dust. The Aim: To describe SBS in connection with exposure to indoor air dampness microbiota (DM). Methods: A search through Medline/Pubmed. Results and Conclusions: Chronic course of SBS may be avoided. By contrast, persistent or cumulative exposure to DM may make SBS potentially life-threatening and lead to irreversible dampness and mold hypersensitivity syndrome (DMHS). The corner feature of DMHS is acquired by dysregulation of the immune system in the direction of hypersensitivities (types I-IV) and simultaneous deprivation of immunity that manifests as increased susceptibility to infections. DMHS is a systemic low-grade inflammation and a biotoxicosis. There is already some evidence that DMHS may be linked to autoimmunity. Autoantibodies towards, e.g., myelin basic protein, myelin-associated glycoprotein, ganglioside GM1, smooth muscle cells and antinuclear autoantibodies were reported in mold-related illness. DMHS is also a mitochondropathy and endocrinopathy. The association of autoimmunity with DMHS should be confirmed through cohort studies preferably using chip-based technology.

The role of nitric oxide in glutaric acid-induced convulsive behavior in pup rats

Glutaric acidaemia type I (GA-I) is a cerebral organic disorder characterized by the accumulation of glutaric acid (GA) and seizures. As seizures are precipitated in children with GA-I and the mechanisms underlying this disorder are not well established, we decided to investigate the role of nitric oxide (NO) in GA-induced convulsive behaviour in pup rats. Pup male Wistar rats (18-day-old) were anesthetized and placed in stereotaxic apparatus for cannula insertion into the striatum for injection of GA. The experiments were performed 3 days after surgery (pup rats 21-day-old). An inhibitor of NO synthesis (N-G-nitro-l-arginine methyl ester-L-NAME, 40 mg/kg) or saline (vehicle) was administered intraperitoneally 30 min before the intrastriatal injection of GA (1 µl, 1.3 µmol/striatum) or saline. Immediately after the intrastriatal injections, the latency and duration of seizures were recorded for 20 min. The administration of L-NAME significantly increased the latency to the first seizure episode and reduced the duration of seizures induced by GA in pup rats. The administration of the NO precursor l-arginine (L-ARG; 80 mg/kg) prevented the effects of L-NAME. Besides, GA significantly increased nitrate and nitrite (NOx) levels in the striatum of pup rats and the preadministration of L-NAME prevented this alteration. L-ARG blocked the reduction of striatal NOx provoked by L-NAME. These results are experimental evidence that NO plays a role in the seizures induced by GA in pup rats, being valuable in understanding the physiopathology of neurological signs observed in children with this organic acidaemia and to develop new therapeutic strategies.

Dual roles of astrocytes in plasticity and reconstruction after traumatic brain injury

Traumatic brain injury (TBI) is one of the leading causes of fatality and disability worldwide. Despite its high prevalence, effective treatment strategies for TBI are limited. Traumatic brain injury induces structural and functional alterations of astrocytes, the most abundant cell type in the brain. As a way of coping with the trauma, astrocytes respond in diverse mechanisms that result in reactive astrogliosis. Astrocytes are involved in the physiopathologic mechanisms of TBI in an extensive and sophisticated manner. Notably, astrocytes have dual roles in TBI, and some astrocyte-derived factors have double and opposite properties. Thus, the suppression or promotion of reactive astrogliosis does not have a substantial curative effect. In contrast, selective stimulation of the beneficial astrocyte-derived molecules and simultaneous attenuation of the deleterious factors based on the spatiotemporal-environment can provide a promising astrocyte-targeting therapeutic strategy. In the current review, we describe for the first time the specific dual roles of astrocytes in neuronal plasticity and reconstruction, including neurogenesis, synaptogenesis, angiogenesis, repair of the blood-brain barrier, and glial scar formation after TBI. We have also classified astrocyte-derived factors depending on their neuroprotective and neurotoxic roles to design more appropriate targeted therapies.

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.