Post-Traumatic Epilepsy and Comorbidities: Advanced Models, Molecular Mechanisms, Biomarkers, and Novel Therapeutic Interventions

Molecular and functional changes in GABAergic transmission during epileptogenesis in a rat model of post-traumatic epilepsy

Traumatic brain injury (TBI) is one of the leading causes of structural epilepsy. Our objective was to investigate the molecular and functional dysregulation of GABAergic neurotransmission during a wide time window from acute to chronic phases of epileptogenesis after TBI. Perilesional and thalamic tissues sampled from a clinically relevant animal model of post-traumatic epilepsy induced by lateral fluid-percussion injury were investigated using in situ hybridization, immunohistochemistry and RNA sequencing. For functional analysis, we utilized a membrane microtransplantation technique in Xenopus oocytes in order to overcome the technical difficulties that would stem from recording directly from highly damaged lesional and perilesional brain tissues. Already at 6 to 24 h post-TBI we found a dysregulation in the expression of GABAAR β3- and δ-subunits, which persisted for up to 4 months. Further, gene set enrichment analysis revealed a negative enrichment of GABA receptor signaling in the perilesional cortex and ipsilateral thalamus. These changes occurred in parallel to the dysregulation of the two main cation-chloride cotransporter genes (Slc12a2 and Slc12a5) both in the perilesional cortex and the ipsilateral thalamus. Our functional analysis revealed that the GABA current reversal potential (EGABA) was shifted towards more depolarized values in the perilesional cortex and ipsilateral thalamus. Our data demonstrate a rapid onset and long-lasting duration of GABAergic dysfunction after TBI and support the hypothesis that an early treatment with agents modulating the GABAergic transmission in the thalamo-cortical-thalamic circuitry may suppress early seizures as well as prevent or slow down epileptogenesis after TBI.

Mitigation of Acute Seizures and Neuropathology after Traumatic Brain Injury by Structure-Based Discovery-Identified Drugs

Our objective was to test the hypothesis that structure-based identified or designed compounds exhibiting neuroprotective, antioxidant, and anti-inflammatory properties in vitro will mitigate early seizures and neuropathology after traumatic brain injury (TBI) in vivo. The neuroprotective and anti-inflammatory effects of 11 compounds identified by computer-assisted approximations were tested in vitro in neuronal microglial co-cultures. Among these, compound FBA exhibited the best neuroprotective (MAP-2, microtubule-associated-protein 2, a neuronal damage biomarker), antioxidative (nitrite production), and anti-inflammatory effects in vitro (all p < 0.01). Consequently, its neuroprotective and antiseizure effects were assessed in vivo in adult male Sprague-Dawley rats exposed to severe lateral fluid-percussion-induced TBI. Rats under continuous video-electroencephalogram monitoring received prophylactic treatment with an intraperitoneal (i.p.) injection of FBA (FBApro, 30 mg/kg) or vehicle (VEH, 48% PEG in 0.9% saline, 3 mL/kg) at 2 and 24 h post-TBI. Rats that developed status epilepticus received 1-2 additional on-demand FBA doses (FBApro+, 100 mg/kg, i.p.) to stop epileptiform activity. FBApro treatment reduced the cortical lesion area (18.9 ± 4.1 mm2, n = 7) compared with VEH treatment (24.8 ± 5.7 mm2, n = 10, p < 0.05). FBApro treatment also showed a favorable effect on the white matter by reducing plasma levels of pNF-H, a biomarker of axonal injury, compared with VEH treatment (Cohen's delta 0.657). Both FBApro (368 ± 407 s) and FBApro+ (256 ± 327 s) treatments reduced the average cumulative seizure duration compared with VEH (896 ± 703 s, both p < 0.05). The FBApro+ treatment regimen also reduced the mean relative theta and alpha power and increased the mean relative gamma power in the electroencephalogram (p < 0.05). Our data identified FBA as a novel structure-based discovered compound with promising favorable effects on structural and functional recovery after TBI.

HMGB1 blood levels and neurological outcomes after traumatic brain injury: Insights from an exploratory study

OBJECTIVE

Posttraumatic epilepsy (PTE) and cognitive impairment are severe complications following traumatic brain injury (TBI). Neuroinflammation likely contributes, but the role of specific inflammatory mediators requires clarification. High-mobility group box 1 (HMGB1) is an inflammatory cytokine released after brain injury that may be involved. This prospective longitudinal study investigated whether serum HMGB1 levels are associated with PTE development and cognitive decline over 12 months post-TBI.

METHODS

Serum samples were collected from 41 TBI patients, including mild and moderate to severe, at baseline, 6, and 12 months following TBI. HMGB1 was quantified by ELISA alongside interleukin-1β (IL-1β) and tumor necrosis factor (TNF). Cognitive assessments using validated neuropsychological assessments were performed at 6 and 12 months. The occurrence of PTE was also tracked.

RESULTS

HMGB1 remained elevated at 12 months post-TBI only in the subgroup (n = 6) that developed PTE (p = 0.026). PTE was associated with moderate to severe TBI cases. Higher HMGB1 levels at 12 months correlated with a greater decline in Addenbrooke's Cognitive Examination scores (p < 0.05). Reductions in HMGB1 (p < 0.05), IL-1β (p < 0.05) and TNF (p < 0.001) levels from 6 to 12 months correlated with improvements in cognitive scores. Multivariate regression analysis confirmed that HMGB1 level changes were independently associated with cognitive trajectory post-TBI (p = 0.003).

SIGNIFICANCE

The study highlights the importance of understanding the interactions between HMGB1 and inflammatory markers in posttraumatic neuroinflammatory responses. Targeting HMGB1 and associated markers may offer a promising strategy for managing chronic neuroinflammation and mitigating cognitive deficits in TBI patients, emphasizing the potential for targeted therapeutic interventions in this context.

PLAIN LANGUAGE SUMMARY

This study examines how a protein called HMGB1 may contribute to epilepsy and cognitive deficits after traumatic brain injury (TBI). Patients with higher HMGB1 levels were more likely to develop epilepsy and experience significant cognitive decline within a year. Reducing HMGB1 and related inflammation was associated with better cognitive function and overall brain health. These findings suggest that HMGB1 could be a valuable marker and a potential target for treatments to prevent epilepsy and improve brain recovery after TBI.

Antiseizure medication use in acute symptomatic seizures: A narrative review

Acute symptomatic seizures, occurring shortly after a central nervous system insult, constitute nearly half of all seizure cases. However, there is a conspicuous absence of clear, comprehensive, and cohesive guidelines for the management of these seizures with antiseizure medications, especially their duration of use. This lack of consensus on the optimal duration of therapy leads to prolonged treatments that may carry adverse consequences. The primary objective of this narrative review is to present the existing evidence-based literature on the management of acute symptomatic seizures within the context of the underlying pathologies that trigger them. We explore the risk of developing epilepsy for each specific etiology and identify the factors that influence this risk. Finally, to facilitate decision-making regarding treatment duration, we categorize acute seizures based on the temporal characteristics of hyperexcitability as acute, subacute, and prolonged. Such a rubric may offer clarity in an area where consensus and guidelines are lacking.

Glioma-induced alterations in excitatory neurons are reversed by mTOR inhibition

Gliomas are aggressive neoplasms that diffusely infiltrate the brain and cause neurological symptoms, including cognitive deficits and seizures. Increased mTOR signaling has been implicated in glioma-induced neuronal hyperexcitability, but the molecular and functional consequences have not been identified. Here, we show three types of changes in tumor-associated neurons: (1) downregulation of transcripts encoding excitatory and inhibitory postsynaptic proteins and dendritic spine development and upregulation of cytoskeletal transcripts via neuron-specific profiling of ribosome-bound mRNA, (2) marked decreases in dendritic spine density via light and electron microscopy, and (3) progressive functional alterations leading to neuronal hyperexcitability via in vivo calcium imaging. A single acute dose of AZD8055, a combined mTORC1/2 inhibitor, reversed these tumor-induced changes. These findings reveal mTOR-driven pathological plasticity in neurons at the infiltrative margin of glioma and suggest new strategies for treating glioma-associated neurological symptoms.

Treatment options for post-traumatic epilepsy: an update on clinical and translational aspects

INTRODUCTION

Post-traumatic epilepsy (PTE) accounts for 10% to 20% of all symptomatic epilepsies and 5% of all forms of epilepsy, and drug resistance is reported in up to 45% of cases.

AREAS COVERED

This is a focused narrative review that discusses the available data on the current and new PTE treatments, giving particular attention to the last 10 years.

EXPERT OPINION

Despite the disappointing results of many antiseizure medications (ASMs) in preventing epileptogenicity, it is still unclear whether the early intervention could lead to different clinical phenotypes in terms, for example, of seizure severity, drug resistance and comorbidity patterns. The same applies to compounds targeting neuroinflammation, oxidative stress and neurotransmission modulation. The heterogeneity of etiologies leading to PTE has limited the investigation and implementation of specific interventions. New studies must focus on identifying common pathways and mechanisms shared by different etiological processes, identifying biomarkers, and validating animal models of epileptogenesis concerning PTE. Drug repurposing research will facilitate rapid translation into clinical research. Multitarget drug combinations will also receive increasing attention. In terms of non-pharmacological treatments, Vagus Nerve Stimulation seems to be a good option, while epilepsy surgery and Deep Brain Stimulation deserve further attention.

Animal welfare assessment after controlled cortical impact in CD-1 mice - A model of posttraumatic epilepsy

The ethical use of laboratory animals requires that the benefits of an experimental study are carefully weighed against potential harm to the animals. In traumatic brain injury (TBI) research, ethical concerns are especially relevant to severe TBI, after which animals may experience suffering, depending on the implementation of refinement measures such as (1) postsurgical analgesia during the initial period following TBI and (2) humane endpoints. However, despite the frequent use of rodent models such as fluid percussion injury (FPI) and controlled cortical impact (CCI) in rats or mice, there is only one recent study that applied assessment of welfare to a severe TBI model, the FPI model in rats. In the present pilot study in a CCI mouse model of posttraumatic epilepsy, we assessed animal welfare by a brain injury-specific severity scoresheet. Furthermore, nest building was used as a sensitive indicator of health and welfare in laboratory mice. Sham mice that underwent craniotomy but not CCI were used for comparison. Craniotomy and CCI were performed under anesthesia with isoflurane, followed by 3 days of postsurgical analgesia with the opioid l-methadone. Mannitol was used to prevent the head pain caused by increased intracranial pressure. Using the TBI-specific scoresheet to describe and monitor potential distress in animals, moderately increased scores were determined in CCI mice only over the first 2 days after surgery, indicating that animal suffering in this model is transitory. Similarly, significantly impaired nest building was observed at 1 but not 7 days after CCI. We conclude that with effective postsurgical analgesia and mannitol behavioral recovery is rapid in mice after CCI.

Differential Expression of hsa-miR-134, hsa-miR-155, hsa-miR-122 as Biomarkers of Epileptogenesis in Patients with Acute Cerebral Injury

It is difficult to predict the process of occurrence of an epileptogenic focus in patients who have suffered acute cerebral damage. The aim of our study is to investigate and describe the possibility of using microRNAs as biomarkers of epileptogenesis. Objective of our work was to evaluate expression of hsa-miR-134-5p, hsa-miR-155-5p, and has-miR-122-5p in different groups of patients. Quantitative comparison of relative concentrations of the studied microRNAs in the blood plasma of three groups of patients was carried out: Group I - patients with temporal lobe epilepsy; Group II - patients with potential epileptogenic injuries; Group III - control group. The study showed increased expression of hsa-miR-134-5p in patients with temporal lobe epilepsy, which confirms the published data on its involvement in the mechanisms of epileptogenesis. Hsa-miR-155-5p was overexpressed in the Group II in comparison with other groups, the data indicate involvement in the mechanisms of inflammation, which could indirectly affect occurrence of epilepsy. Hsa-miR-122-5p was overexpressed in two study groups, but the levels were higher in the group of patients with acute cerebral injuries. The obtained results allow us to propose has-miR-122-5p as a potential biomarker of epileptogenesis.

EEG hyperexcitability and hyperconnectivity linked to GABAergic inhibitory interneuron loss following traumatic brain injury

Traumatic brain injury represents a significant global health burden and has the highest prevalence among neurological disorders. Even mild traumatic brain injury can induce subtle, long-lasting changes that increase the risk of future neurodegeneration. Importantly, this can be challenging to detect through conventional neurological assessment. This underscores the need for more sensitive diagnostic tools, such as electroencephalography, to uncover opportunities for therapeutic intervention. Progress in the field has been hindered by a lack of studies linking mechanistic insights at the microscopic level from animal models to the macroscale phenotypes observed in clinical imaging. Our study addresses this gap by investigating a rat model of mild blast traumatic brain injury using both immunohistochemical staining of inhibitory interneurons and translationally relevant electroencephalography recordings. Although we observed no pronounced effects immediately post-injury, chronic time points revealed broadband hyperexcitability and increased connectivity, accompanied by decreased density of inhibitory interneurons. This pattern suggests a disruption in the balance between excitation and inhibition, providing a crucial link between cellular mechanisms and clinical hallmarks of injury. Our findings have significant implications for the diagnosis, monitoring, and treatment of traumatic brain injury. The emergence of electroencephalography abnormalities at chronic time points, despite the absence of immediate effects, highlights the importance of long-term monitoring in traumatic brain injury patients. The observed decrease in inhibitory interneuron density offers a potential cellular mechanism underlying the electroencephalography changes and may represent a target for therapeutic intervention. This study demonstrates the value of combining cellular-level analysis with macroscale neurophysiological recordings in animal models to elucidate the pathophysiology of traumatic brain injury. Future research should focus on translating these findings to human studies and exploring potential therapeutic strategies targeting the excitation-inhibition imbalance in traumatic brain injury.

Behavioral Assays for Comprehensive Evaluation of Cognitive and Neuropsychiatric Comorbidities of Traumatic Brain Injury and Chronic Neurological Disorders

Neurological deficits, psychiatric disorders, and cognitive impairments often accompany stroke, brain injury, epilepsy, and many neurological disorders, which present intricate comorbidities that challenge recognition and management. There are many tools and paradigms for evaluating learning, memory, anxiety, and depression-like behaviors in lab animal models of brain disorders. However, there is a significant gap between clinical observations and experimental models, which limit understanding of the complex interplay between chronic brain conditions and their impact on cognitive dysfunction and psychiatric impairments. This article describes an overview of experimental rationale, methods, protocols, and strategies for evaluating sensorimotor, affective and cognitive-associated comorbid behaviors in epilepsy, traumatic brain injury (TBI), stroke, spinal cord injury (SCI), and many other neurological disorders. First, we delve into clinical evidence elucidating the profound impact of comorbidities, e.g., psychiatric disorders and cognitive deficits, in individuals with epilepsy. Then, we discuss diverse approaches to assess these comorbidities in experimental models of brain diseases. Finally, we explore the methodologies for assessing motor function, sensorimotor, behavior, and psychiatric health. We cover strategies and protocols enabling these assays, including implementing behavioral paradigms to assess learning and memory, anxiety, and depression-like behaviors in rodents in health and disease conditions. It is essential to consider a comprehensive battery of tests to investigate various behavioral deficits, considering environment, age, and sex differences relevant to the disease, such as TBI, SCI, epilepsy, stroke, and other complex neurological conditions. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC.

Kindling Models of Epileptogenesis for Developing Disease-Modifying Drugs for Epilepsy

Kindling models are widely used animal models to study the pathobiology of epilepsy and epileptogenesis. These models exhibit distinctive features whereby sub-threshold stimuli instigate the initial induction of brief focal seizures. Over time, the severity and duration of these seizures progressively increase, leading to a fully epileptic state, which is marked by consistent development of generalized tonic-clonic seizures. Kindling involves focal stimulation via implanted depth electrodes or repeated administration of chemoconvulsants such as pentylenetetrazol. Comparative analysis of preclinical and clinical findings has confirmed a high predictive validity of fully kindled animals for testing novel antiseizure medications. Thus, kindling models remain an essential component of anticonvulsant drug development programs. This article provides a comprehensive guide to working protocols, testing of therapeutic drugs, outcome parameters, troubleshooting, and data analysis for various electrical and chemical kindling epileptogenesis models for new therapeutic development and optimization. The use of pharmacological agents or genetically modified mice in kindling experiments is valuable, offering insights into the impact of a specific target on various aspects of seizures, including thresholds, initiation, spread, termination, and the generation of a hyperexcitable network. These kindling epileptogenesis paradigms are helpful in identifying mechanisms and disease-modifying interventions for epilepsy. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Hippocampal kindling Basic Protocol 2: Amygdala kindling Basic Protocol 3: Rapid hippocampal kindling Basic Protocol 4: Chemical kindling.

Enhancing cognitive recovery in chronic traumatic brain injury through simultaneous allosteric modulation of α7 nicotinic acetylcholine and α5 GABAA receptors

Traumatic brain injury (TBI) leads to changes in the neural circuitry of the hippocampus that result in chronic learning and memory deficits. However, effective therapeutic strategies to ameliorate these chronic learning and memory impairments after TBI are limited. Two pharmacological targets for enhancing cognition are nicotinic acetylcholine receptors (nAChRs) and GABAA receptors (GABAARs), both of which regulate hippocampal network activity to form declarative memories. A promising compound, 522-054, both allosterically enhances α7 nAChRs and inhibits α5 subunit-containing GABAARs. Administration of 522-054 enhances long-term potentiation (LTP) and cognitive functioning in non-injured animals. In this study, we assessed the effects of 522-054 on hippocampal synaptic plasticity and learning and memory deficits in the chronic post-TBI recovery period. Adult male Sprague Dawley rats received moderate parasagittal fluid-percussion brain injury or sham surgery. At 12 wk after injury, we assessed basal synaptic transmission and LTP at the Schaffer collateral-CA1 synapse of the hippocampus. Bath application of 522-054 to hippocampal slices reduced deficits in basal synaptic transmission and recovered TBI-induced impairments in LTP. Moreover, treatment of animals with 522-054 at 12 wk post-TBI improved cue and contextual fear memory and water maze acquisition and retention without a measurable effect on cortical or hippocampal atrophy. These results suggest that dual allosteric modulation of α7 nAChR and α5 GABAAR signaling may be a potential therapy for treating cognitive deficits during chronic recovery from TBI.

In Vivo Evaluation of Self-assembled nano-Saikosaponin-a for Epilepsy Treatment

Saikosaponin-a (SSa) exhibits antiepileptic effects. However, its poor water solubility and inability to pass through the blood-brain barrier greatly limit its clinical development and application. In this study, SSa-loaded Methoxy poly (ethylene glycol)-poly(ε-caprolactone) (MePEG-SSa-PCL) NPs were successfully prepared and characterized. Our objective was to further investigate the effect of this composite on acute seizure in mice. First, we confirmed the particle size and surface potential of the composite (51.00 ± 0.25 nm and - 33.77 ± 2.04 mV, respectively). Further, we compared the effects of various MePEG-SSa-PCL doses (low, medium, and high) with those of free SSa, valproic acid (VPA - positive control), and saline only (model group) on acute seizure using three different acute epilepsy mouse models. We observed that compared with the model group, the three MePEG-SSa-PCL treatments showed significantly lowered seizure frequency in mice belonging to the maximum electroconvulsive model group. In the pentylenetetrazol and kainic acid (KA) acute epilepsy models, MePEG-SSa-PCL increased both clonic and convulsion latency periods and shortened convulsion duration more effectively than equivalent SSa-only doses. Furthermore, hematoxylin-eosin and Nissl staining revealed considerably less neuronal damage in the hippocampal CA3 area of KA mice in the SSa, VPA, and three MePEG-SSa-PCL groups relative to mice in the model group. Hippocampal gamma-aminobutyric acid-A (GABA-A) receptor and cleaved caspase-3 expression levels in KA mice were significantly higher and lower, respectively, in the three MePEG-SSa-PCL treatment groups than in the model group. Thus, MePEG-SSa-PCL exhibited a more potent antiepileptic effect than SSa in acute mouse epilepsy models and could alleviate neuronal damage in the hippocampus following epileptic seizures, possibly via GABA-A receptor expression upregulation.

The predicative value of early quantitative electroencephalograph in epilepsy after severe traumatic brain injury in children

Objective

To explore whether early quantitative electroencephalograph (EEG) can predict the development of epilepsy in pediatric patients with severe traumatic brain injury (TBI).

Methods

A total of 78 children with severe TBI who were admitted to our hospital were divided into post-traumatic epilepsy (PTE) and non-PTE groups according to whether or not they developed PTE. EEGs of frontal, central and parietal lobes were recorded at the time of their admission. The power values of each frequency band, odds ratio and peak envelope power values of each brain region were statistically analyzed. In addition, the patients were followed up for two years, and the occurrence of PTE was documented.

Results

During the follow-up period, PTE occurred in 8 patients. Analysis of EEG signals across different brain regions (frontal, central, and parietal lobes) revealed significant differences between the PTE and non-PTE groups. Patients with PTE exhibited significantly higher δ and θ power values (P < 0.01), lower α/θ ratios (P < 0.01), and elevated θ/β, (δ + θ)/(α + β), and peak envelope power (P < 0.01) compared to those in the non-PTE group.

Conclusion

In children with severe TBI, the parameter characterization of early quantitative EEG has potential application in predicting PTE.

Seizure-Related Head Injuries: A Narrative Review

Epilepsy is one of the most common neurological diseases. Epileptic seizures very often result in head injuries that may lead to many adverse consequences, both acute and chronic. They contribute to the need for hospitalization, modification of treatment, and a general decline in social productivity. The objective of our review is to characterize and assess management aspects of seizure-related head injuries (SRHIs) as an important and frequent clinical problem present in emergency department settings. PubMed and other relevant databases and websites were systematically searched for articles on traumatic brain injuries connected with the occurrence of seizures published from inception to 9 April 2024; then, we reviewed the available literature. Our review showed that SRHIs can lead to various acute complications, in some cases requiring hospitalization and neurosurgical intervention. Long-term complications and cognitive decline after injury might be present, eventually implying a negative impact on a patient's quality of life. Despite being frequent and clinically important, there are still no widely accepted, uniform recommendations for the management of patients with SRHIs. As such, a concise and standardized protocol for the management of seizure-related head injuries in emergency departments is worth consideration.

The Neurovascular Unit Dysfunction in the Molecular Mechanisms of Epileptogenesis and Targeted Therapy

Epilepsy is a multifaceted neurological syndrome characterized by recurrent, spontaneous, and synchronous seizures. The pathogenesis of epilepsy, known as epileptogenesis, involves intricate changes in neurons, neuroglia, and endothelium, leading to structural and functional disorders within neurovascular units and culminating in the development of spontaneous epilepsy. Although current research on epilepsy treatments primarily centers around anti-seizure drugs, it is imperative to seek effective interventions capable of disrupting epileptogenesis. To this end, a comprehensive exploration of the changes and the molecular mechanisms underlying epileptogenesis holds the promise of identifying vital biomarkers for accurate diagnosis and potential therapeutic targets. Emphasizing early diagnosis and timely intervention is paramount, as it stands to significantly improve patient prognosis and alleviate the socioeconomic burden. In this review, we highlight the changes and molecular mechanisms of the neurovascular unit in epileptogenesis and provide a theoretical basis for identifying biomarkers and drug targets.

Posttraumatic epilepsy in chronic disorders of consciousness due to severe traumatic brain injury after traffic accidents

PURPOSE

To evaluate the clinical state of posttraumatic epilepsy (PTE) in patients with chronic disorders of consciousness (CDC) due to severe traumatic brain injury (STBI) after traffic accidents and clarify the risk factors for seizure occurrence in such patients.

METHODS

Two hundred ninety-three patients with CDC due to STBI (mean age at admission [±standard deviation]: 36.4 ± 17.9 years; men: 71.7 %; mean duration of injury to admission: 416 ± 732 days; mean hospitalization time: 899 ± 319 days) were enrolled in this study. We retrospectively investigated the relationship between seizure conditions (type and frequency) and clinical data, including age, sex, pathological types of brain injury, with/without surgical intervention, degree of CDC, and administration of antiseizure medications (ASMs).

RESULTS

Overall, 52.9 % (n = 155/293) and 64.2 % of the patients (n = 183/of 285 patients surviving at discharge) were administered ASMs at admission and discharge, respectively. One hundred thirty-two patients (45.1 %) experienced epileptic seizures during hospitalization, and the mean seizure frequency was 4.0 ± 0.4 times per year. In multivariate analysis, significant and independent risk factors of seizure occurrence were revealed to be male sex, high National Agency for Automotive Safety and Victims' Aid score, hypoxic encephalopathy, and history of the neurosurgical operations.

CONCLUSION

The high prevalence of PTE in patients with CDC due to STBI, and the significant and independent risk factors for seizure occurrence in the chronic clinical phase were revealed. We expect that this study will aid toward improving clinical assessment and management of epileptic seizures in the population.

Mechanistic and therapeutic relationships of traumatic brain injury and γ-amino-butyric acid (GABA)

Traumatic brain injury (TBI) is a highly prevalent medical condition for which no medications specific for the prophylaxis or treatment of the condition as a whole exist. The spectrum of symptoms includes coma, headache, seizures, cognitive impairment, depression, and anxiety. Although it has been known for years that the inhibitory neurotransmitter γ-amino-butyric acid (GABA) is involved in TBI, no novel therapeutics based upon this mechanism have been introduced into clinical practice. We review the neuroanatomical, neurophysiological, neurochemical, and neuropharmacological relationships of GABA neurotransmission to TBI with a view toward new potential GABA-based medicines. The long-standing idea that excitatory and inhibitory (GABA and others) balances are disrupted by TBI is supported by the experimental data but has failed to invent novel methods of restoring this balance. The slow progress in advancing new treatments is due to the complexity of the disorder that encompasses multiple dynamically interacting biological processes including hemodynamic and metabolic systems, neurodegeneration and neurogenesis, major disruptions in neural networks and axons, frank brain lesions, and a multitude of symptoms that have differential neuronal and neurohormonal regulatory mechanisms. Although the current and ongoing clinical studies include GABAergic drugs, no novel GABA compounds are being explored. It is suggested that filling the gap in understanding the roles played by specific GABAA receptor configurations within specific neuronal circuits could help define new therapeutic approaches. Further research into the temporal and spatial delivery of GABA modulators should also be useful. Along with GABA modulation, research into the sequencing of GABA and non-GABA treatments will be needed.

Comparison of the efficacy and safety of sodium valproate versus levetiracetam in the treatment of severe traumatic brain injury

OBJECTIVE

To observe the efficacy and safety of sodium valproate (VPA) compared to levetiracetam (LEV) in the treatment of severe traumatic brain injury (sTBI).

METHODS

In this blind, prospective study, eighty-four sTBI patients who had craniotomy from August 2021 to August 2023 were randomly split into two groups through random number table method: LEV and VPA, each with 42 patients. Both received comprehensive treatment post-craniotomy. LEV group: LEV injection on surgery day, transitioning to LEV tablets from day two. VPA group: VPA injection on surgery day, switching to VPA extended-release tablets from day two. The study compared hospital stay, neurological function, clinical outcomes, seizures, and drug reactions between groups.

RESULTS

The length of hospital stay showed no significant difference between the LEV and VPA groups. Both groups demonstrated improved neurological function post-treatment (NIHSS and BI scores), with no significant between-group differences. Clinical outcomes at 3 months post-treatment were similar in both groups. Seizure occurrence within 3 months after treatment showed no significant difference between the LEV (19.05%) and VPA (23.81%) groups. However, the VPA group experienced a significantly higher rate of drug-related adverse reactions (40.48%) compared to the LEV group (21.43%).

CONCLUSION

Both VPA and LEV are effective in treating sTBI, showing no significant difference in improving neurological function, daily life abilities, treatment outcomes, and seizure occurrence. However, VPA treatment exhibited a significantly higher incidence of drug-related adverse reactions compared to LEV, indicating that LEV might be a safer option for sTBI treatment.

Resting-State Functional Magnetic Resonance Imaging Network Association With Mortality, Epilepsy, Cognition, and Motor Two-Year Outcomes in Suspected Severe Neonatal Acute Brain Injury

BACKGROUND AND OBJECTIVES

In acute brain injury of neonates, resting-state functional magnetic resonance imaging (MRI) (RS) showed incremental association with consciousness, mortality, cognitive and motor development, and epilepsy, with correction for multiple comparisons, at six months postgestation in neonates with suspected acute brain injury (ABI). However, there are relatively few developmental milestones at six months to benchmark against, thus, we extended this cohort study to evaluate two-year outcomes.

METHODS

In 40 consecutive neonates with ABI and RS, ordinal scores of resting-state networks; MRI, magnetic resonance spectroscopy, and electroencephalography; and up to 42-month outcomes of mortality, general and motor development, Pediatric Cerebral Performance Category Scale (PCPC), and epilepsy informed associations between tests and outcomes.

RESULTS

Mean gestational age was 37.8 weeks, 68% were male, and 60% had hypoxic-ischemic encephalopathy. Three died in-hospital, four at six to 42 months, and five were lost to follow-up. Associations included basal ganglia network with PCPC (P = 0.0003), all-mortality (P = 0.005), and motor (P = 0.0004); language/frontoparietal network with developmental delay (P = 0.009), PCPC (P = 0.006), and all-mortality (P = 0.01); default mode network with developmental delay (P = 0.003), PCPC (P = 0.004), neonatal intensive care unit mortality (P = 0.01), and motor (P = 0.009); RS seizure onset zone with epilepsy (P = 0.01); and anatomic MRI with epilepsy (P = 0.01).

CONCLUSION

For the first time, at any age, resting state functional MRI in ABI is associated with long-term epilepsy and RSNs predicted mortality in neonates. Severity of RSN abnormality was associated with incrementally worsened neurodevelopment including cognition, language, and motor function over two years.

Increased Expression of KNa1.2 Channel by MAPK Pathway Regulates Neuronal Activity Following Traumatic Brain Injury

Recent studies have indicated that functional abnormalities in the KNa1.2 channel are linked to epileptic encephalopathies. However, the role of KNa1.2 channel in traumatic brain injury (TBI) remains limited. We collected brain tissue from the TBI mice and patients with post-traumatic epilepsy (PTE) to determine changes in KNa1.2 channel following TBI. We also investigated whether the MAPK pathway, which was activated by the released cytokines after injury, regulated KNa1.2 channel in in vitro. Finally, to elucidate the physiological significance of KNa1.2 channel in neuronal excitability, we utilized the null mutant-Kcnt2-/- mice and compared their behavior patterns, seizure susceptibility, and neuronal firing properties to wild type (WT) mice. TBI was induced in both Kcnt2-/- and WT mice to investigate any differences between the two groups under pathological condition. Our findings revealed that the expression of KNa1.2 channel was notably increased only during the acute phase following TBI, while no significant elevation was observed during the late phase. Furthermore, we identified the released cytokines and activated MAPK pathway in the neurons after TBI and confirmed that KNa1.2 channel was enhanced by the MAPK pathway via stimulation of TNF-α. Subsequently, compared to WT mice, neurons from Kcnt2-/- mice showed increased neuronal excitability and Kcnt2-/- mice displayed motor deficits and enhanced seizure susceptibility, which suggested that KNa1.2 channel may be neuroprotective. Therefore, this study suggests that enhanced KNa1.2 channel, facilitated by the inflammatory response, may exert a protective role in an acute phase of the TBI model.

Clinical characteristics and associated factors of posttraumatic epilepsy after traumatic brain injury in children: A retrospective case-control study

BACKGROUND

Traumatic brain injury (TBI) affects approximately 69 million individuals annually, often resulting in well-documented complications such as epilepsy. Although numerous studies have been performed on posttraumatic epilepsy (PTE) in adults over the past decade, research on chronic consequences of TBI in children remains limited. Herein, we retrospectively assessed children who had experienced moderate to severe TBI to determine their clinical characteristics and identify associated factors associated with the development of PTE in the pediatric population.

METHODS

The study population comprised children aged 0-18 years who had experienced moderate to severe TBI and underwent treatment at the Children's Hospital of Chongqing Medical University between 2011 and 2021. They were categorized into two groups: the PTE group, comprising individuals diagnosed with PTE within a one-year follow-up period, and the nPTE group, consisting of those who did not develop PTE during the same timeframe. The primary objective was to investigate the clinical characteristics and identify related associated factors. The relationship between various clinical factors and the incidence of PTE was assessed through univariate and multivariate logistic regression.

RESULTS

A total of 132 patients were assessed. Most participants were male (65%) and the age distribution skewed towards younger children, with a median age of 41.0 months (interquartile range: 45.3). Upon their last clinical visit, 64 children (49%) were diagnosed with PTE. Notably, the first posttraumatic seizure predominantly occurred within the first week following the traumatic event. Further analyses revealed that increasing injury severity, as indicated by a lower Glasgow Coma Scale (GCS) score (odds ratio [OR]: 0.78, 95% confidence interval [CI]: 0.54-1.12, p= 0.018), a contusion load ≥3 (OR: 8.1, 95% CI: 2.3-28.9, p= 0.001), immediate posttraumatic seizures (IPTS) (OR: 8.9, 95% CI: 2.5-31.2, p < 0.001), and early posttraumatic seizures (EPTS) (OR: 54, 95% CI: 11-276, p < 0.001), were all significantly associated with a higher risk of developing PTE.

CONCLUSION

This study highlights that the onset of PTE was associated with the markers of injury severity or PTS and identified GCS scores, contusion loads of ≥3, IPTS, and EPTS as independent associated factors significantly associated with the development of PTE.

Antiepileptic Drugs as Potential Dementia Prophylactics Following Traumatic Brain Injury

Seizures and other forms of neurovolatility are emerging as druggable prodromal mechanisms that link traumatic brain injury (TBI) to the progression of later dementias. TBI neurotrauma has both acute and long-term impacts on health, and TBI is a leading risk factor for dementias, including chronic traumatic encephalopathy and Alzheimer's disease. Treatment of TBI already considers acute management of posttraumatic seizures and epilepsy, and impressive efforts have optimized regimens of antiepileptic drugs (AEDs) toward that goal. Here we consider that expanding these management strategies could determine which AED regimens best prevent dementia progression in TBI patients. Challenges with this prophylactic strategy include the potential consequences of prolonged AED treatment and that a large subset of patients are refractory to available AEDs. Addressing these challenges is warranted because the management of seizure activity following TBI offers a rare opportunity to prevent the onset or progression of devastating dementias.

Sleep, oscillations, and epilepsy

Sleep and wake are defined through physiological and behavioral criteria and can be typically separated into non-rapid eye movement (NREM) sleep stages N1, N2, and N3, rapid eye movement (REM) sleep, and wake. Sleep and wake states are not homogenous in time. Their properties vary during the night and day cycle. Given that brain activity changes as a function of NREM, REM, and wake during the night and day cycle, are seizures more likely to occur during NREM, REM, or wake at a specific time? More generally, what is the relationship between sleep-wake cycles and epilepsy? We will review specific examples from clinical data and results from experimental models, focusing on the diversity and heterogeneity of these relationships. We will use a top-down approach, starting with the general architecture of sleep, followed by oscillatory activities, and ending with ionic correlates selected for illustrative purposes, with respect to seizures and interictal spikes. The picture that emerges is that of complexity; sleep disruption and pathological epileptic activities emerge from reorganized circuits. That different circuit alterations can occur across patients and models may explain why sleep alterations and the timing of seizures during the sleep-wake cycle are patient-specific.

MicroRNAs as Potential Biomarkers of Post-Traumatic Epileptogenesis: A Systematic Review

Structural or post-traumatic epilepsy often develops after brain tissue damage caused by traumatic brain injury, stroke, infectious diseases of the brain, etc. Most often, between the initiating event and epilepsy, there is a period without seizures-a latent period. At this time, the process of restructuring of neural networks begins, leading to the formation of epileptiform activity, called epileptogenesis. The prediction of the development of the epileptogenic process is currently an urgent and difficult task. MicroRNAs are inexpensive and minimally invasive biomarkers of biological and pathological processes. The aim of this study is to evaluate the predictive ability of microRNAs to detect the risk of epileptogenesis. In this study, we conducted a systematic search on the MDPI, PubMed, ScienceDirect, and Web of Science platforms. We analyzed publications that studied the aberrant expression of circulating microRNAs in epilepsy, traumatic brain injury, and ischemic stroke in order to search for microRNAs-potential biomarkers for predicting epileptogenesis. Thus, 31 manuscripts examining biomarkers of epilepsy, 19 manuscripts examining biomarkers of traumatic brain injury, and 48 manuscripts examining biomarkers of ischemic stroke based on circulating miRNAs were analyzed. Three miRNAs were studied: miR-21, miR-181a, and miR-155. The findings showed that miR-21 and miR-155 are associated with cell proliferation and apoptosis, and miR-181a is associated with protein modifications. These miRNAs are not strictly specific, but they are involved in processes that may be indirectly associated with epileptogenesis. Also, these microRNAs may be of interest when they are studied in a cohort with each other and with other microRNAs. To further study the microRNA-based biomarkers of epileptogenesis, many factors must be taken into account: the time of sampling, the type of biological fluid, and other nuances. Currently, there is a need for more in-depth and prolonged studies of epileptogenesis.

Microglia in epilepsy

Epilepsy is one of most common chronic neurological disorders, and the antiseizure medications developed by targeting neurocentric mechanisms have not effectively reduced the proportion of patients with drug-resistant epilepsy. Further exploration of the cellular or molecular mechanism of epilepsy is expected to provide new options for treatment. Recently, more and more researches focus on brain network components other than neurons, among which microglia have attracted much attention for their diverse biological functions. As the resident immune cells of the central nervous system, microglia have highly plastic transcription, morphology and functional characteristics, which can change dynamically in a context-dependent manner during the progression of epilepsy. In the pathogenesis of epilepsy, highly reactive microglia interact with other components in the epileptogenic network by performing crucial functions such as secretion of soluble factors and phagocytosis, thus continuously reshaping the landscape of the epileptic brain microenvironment. Indeed, microglia appear to be both pro-epileptic and anti-epileptic under the different spatiotemporal contexts of disease, rendering interventions targeting microglia biologically complex and challenging. This comprehensive review critically summarizes the pathophysiological role of microglia in epileptic brain homeostasis alterations and explores potential therapeutic or modulatory targets for epilepsy targeting microglia.

Microbiota-gut-brain axis and ketogenic diet: how close are we to tackling epilepsy?

The microbiota-gut-brain axis refers to the intricate bidirectional communication between commensal microorganisms residing in the digestive tract and the central nervous system, along neuroendocrine, metabolic, immune, and inflammatory pathways. This axis has been suggested to play a role in several neurological disorders, such as Parkinson's disease, Alzheimer's disease, multiple sclerosis, and epilepsy, paving the way for microbiome-based intervention strategies for the mitigation and treatment of symptoms. Epilepsy is a multifaceted neurological condition affecting more than 50 million individuals worldwide, 30% of whom do not respond to conventional pharmacological therapies. Among the first-hand microbiota modulation strategies, nutritional interventions represent an easily applicable option in both clinical and home settings. In this narrative review, we summarize the mechanisms underlying the microbiota-gut-brain axis involvement in epilepsy, discuss the impact of antiepileptic drugs on the gut microbiome, and then the impact of a particular dietary pattern, the ketogenic diet, on the microbiota-gut-brain axis in epileptic patients. The investigation of the microbiota response to non-pharmacological therapies is an ever-expanding field with the potential to allow the design of increasingly accessible and successful intervention strategies.

Models of traumatic brain injury-highlights and drawbacks

Traumatic brain injury (TBI) is the leading cause for high morbidity and mortality rates in young adults, survivors may suffer from long-term physical, cognitive, and/or psychological disorders. Establishing better models of TBI would further our understanding of the pathophysiology of TBI and develop new potential treatments. A multitude of animal TBI models have been used to replicate the various aspects of human TBI. Although numerous experimental neuroprotective strategies were identified to be effective in animal models, a majority of strategies have failed in phase II or phase III clinical trials. This failure in clinical translation highlights the necessity of revisiting the current status of animal models of TBI and therapeutic strategies. In this review, we elucidate approaches for the generation of animal models and cell models of TBI and summarize their strengths and limitations with the aim of exploring clinically meaningful neuroprotective strategies.

Atypical Neurogenesis, Astrogliosis, and Excessive Hilar Interneuron Loss Are Associated with the Development of Post-Traumatic Epilepsy

BACKGROUND

Traumatic brain injury (TBI) remains a significant risk factor for post-traumatic epilepsy (PTE). The pathophysiological mechanisms underlying the injury-induced epileptogenesis are under investigation. The dentate gyrus-a structure that is highly susceptible to injury-has been implicated in the evolution of seizure development.

METHODS

Utilizing the murine unilateral focal control cortical impact (CCI) injury, we evaluated seizure onset using 24/7 EEG video analysis at 2-4 months post-injury. Cellular changes in the dentate gyrus and hilus of the hippocampus were quantified by unbiased stereology and Imaris image analysis to evaluate Prox1-positive cell migration, astrocyte branching, and morphology, as well as neuronal loss at four months post-injury. Isolation of region-specific astrocytes and RNA-Seq were performed to determine differential gene expression in animals that developed post-traumatic epilepsy (PTE+) vs. those animals that did not (PTE-), which may be associated with epileptogenesis.

RESULTS

CCI injury resulted in 37% PTE incidence, which increased with injury severity and hippocampal damage. Histological assessments uncovered a significant loss of hilar interneurons that coincided with aberrant migration of Prox1-positive granule cells and reduced astroglial branching in PTE+ compared to PTE- mice. We uniquely identified Cst3 as a PTE+-specific gene signature in astrocytes across all brain regions, which showed increased astroglial expression in the PTE+ hilus.

CONCLUSIONS

These findings suggest that epileptogenesis may emerge following TBI due to distinct aberrant cellular remodeling events and key molecular changes in the dentate gyrus of the hippocampus.

Identification of miRNA-mRNA regulatory network associated with the glutamatergic system in post-traumatic epilepsy rats

Background

Glutamate is one of the most important excitatory neurotransmitters in the mammalian brain and is involved in a variety of neurological disorders. Increasing evidence also shows that microRNA (miRNA) and mRNA pairs are engaged in a variety of pathophysiological processes. However, the miRNA and mRNA pairs that affect the glutamatergic system in post-traumatic epilepsy (PTE) remain unknown.

Methods

PTE rats were induced by injecting 0.1 mol/L, 1 μL/min FeCl₂ solution. Behavioral scores and EEG monitoring were used to evaluate whether PTE was successfully induced. RNA-seq was used to obtain mRNA and miRNA expression profiles. Bioinformatics analysis was performed to screen differentially expressed mRNAs and miRNAs associated with the glutamatergic system and then predict miRNA-mRNA interaction pairs. Real-time quantitative reverse transcription PCR was used to further validate the expression of the differential miRNAs and mRNAs. The microRNA-mRNA was subject to the Pearson correlation analysis.

Results

Eight of the 91 differentially expressed mRNAs were associated with the glutamatergic system, of which six were upregulated and two were downregulated. Forty miRNAs were significantly differentially expressed, with 14 upregulated and 26 downregulated genes. The predicted miRNA-mRNA interaction network shows that five of the eight differentially expressed mRNAs associated with the glutamatergic system were targeted by multiple miRNAs, including Slc17a6, Mef2c, Fyn, Slc25a22, and Shank2, while the remaining three mRNAs were not targeted by any miRNAs. Of the 40 differentially expressed miRNAs, seven miRNAs were found to have multiple target mRNAs associated with the glutamatergic system. Real-time quantitative reverse transcription PCR validation and Pearson correlation analysis were performed on these seven targeted miRNAs-Slc17a6, Mef2c, Fyn, Slc25a22, and Shank2-and six additional miRNAs selected from the literature. Real-time quantitative reverse transcription PCR showed that the expression levels of the mRNAs and miRNAs agreed with the predictions in the study. Among them, the miR-98-5p-Slc17a6, miR-335-5p-Slc17a6, miR-30e-5p-Slc17a6, miR-1224-Slc25a22, and miR-211-5p-Slc25a22 pairs were verified to have negative correlations.

Conclusions

Our results indicate that miRNA-mRNA interaction pairs associated with the glutamatergic system are involved in the development of PTE and have potential as diagnostic biomarkers and therapeutic targets for PTE.

Temporal Expression of Neuroinflammatory and Oxidative Stress Markers and Prostaglandin E2 Receptor EP2 Antagonist Effect in a Rat Model of Epileptogenesis

Traumatic brain injury (TBI) in patients results in a massive inflammatory reaction, disruption of blood-brain barrier, and oxidative stress in the brain, and these inciting features may culminate in the emergence of post-traumatic epilepsy (PTE). We hypothesize that targeting these pathways with pharmacological agents could be an effective therapeutic strategy to prevent epileptogenesis. To design therapeutic strategies targeting neuroinflammation and oxidative stress, we utilized a fluid percussion injury (FPI) rat model to study the temporal expression of neuroinflammatory and oxidative stress markers from 3 to 24 h following FPI. FPI results in increased mRNA expression of inflammatory mediators including cyclooxygenase-2 (COX-2) and prostanoid receptor EP2, marker of oxidative stress (NOX2), astrogliosis (GFAP), and microgliosis (CD11b) in ipsilateral cortex and hippocampus. The analysis of protein levels indicated a significant increase in the expression of COX-2 in ipsilateral hippocampus and cortex post-FPI. We tested FPI rats with an EP2 antagonist TG8-260 which produced a statistically significant reduction in the distribution of seizure duration post-FPI and trends toward a reduction in seizure incidence, seizure frequency, and duration, hinting a proof of concept that EP2 antagonism must be further optimized for therapeutic applications to prevent epileptogenesis.

Exploring the pathogenesis linking traumatic brain injury and epilepsy via bioinformatic analyses

Traumatic brain injury (TBI) is a serious disease that could increase the risk of epilepsy. The purpose of this article is to explore the common molecular mechanism in TBI and epilepsy with the aim of providing a theoretical basis for the prevention and treatment of post-traumatic epilepsy (PTE). Two datasets of TBI and epilepsy in the Gene Expression Omnibus (GEO) database were downloaded. Functional enrichment analysis, protein-protein interaction (PPI) network construction, and hub gene identification were performed based on the cross-talk genes of aforementioned two diseases. Another dataset was used to validate these hub genes. Moreover, the abundance of infiltrating immune cells was evaluated through Immune Cell Abundance Identifier (ImmuCellAI). The common microRNAs (miRNAs) between TBI and epilepsy were acquired via the Human microRNA Disease Database (HMDD). The overlapped genes in cross-talk genes and target genes predicted through the TargetScan were obtained to construct the common miRNAs-mRNAs network. A total of 106 cross-talk genes were screened out, including 37 upregulated and 69 downregulated genes. Through the enrichment analyses, we showed that the terms about cytokine and immunity were enriched many times, particularly interferon gamma signaling pathway. Four critical hub genes were screened out for co-expression analysis. The miRNA-mRNA network revealed that three miRNAs may affect the shared interferon-induced genes, which might have essential roles in PTE. Our study showed the potential role of interferon gamma signaling pathway in pathogenesis of PTE, which may provide a promising target for future therapeutic interventions.

Global trends in research of glutamate in epilepsy during past two decades: A bibliometric analysis

Epilepsy affects more than 70 million people in the world. It is characterized by recurrent spontaneous seizures, and it is related to many neurological, cognitive, and psychosocial consequences. Glutamate neurotransmitter dysfunction has essential functions in the pathophysiology of epilepsy. In this work, bibliometric analysis was conducted to explore the trends, frontiers, and hotspots of the global scientific output of glutamate in epilepsy research in the past 20 years. The Science Citation Index Expanded of the Web of Science Core Collection (WoSCC) was searched to obtain information on publications and records published between 2002 and 2021. VOSviewer and CiteSpace were used to conduct bibliometric and visual analyses on the overall distribution of annual output, major countries, active institutions, journals, authors, commonly cited literature, and keywords. The impact and quality of the papers were assessed using the global citation score (GCS). Four thousand eight hundred ninety-one publications were retrieved in total. During the past two decades, the number of publications (Np) associated with glutamate in epilepsy has risen yearly. The United States has published the most papers; its H-index and number of citations are also the highest. The League of European Research Universities (LERU) was the most productive institution. In 2016, the total score of the paper written by Zhang Y was 854, ranking first. The keywords that appear most frequently are “epilepsy,” “glutamate,” “temporal lobe epilepsy (TLE),” “hippocampus,” and “seizures.” This study showed that although the publications related to epileptic glutamate fluctuated slightly, the Np increased overall. The United States is a great creator and influential country in this field. The first three authors are Eid, T., Aronica, E., and Smolders, I. “spectrum,” “animal model,” “inflammation,” “mutation,” “dysfunction,” and “prefrontal cortex” are increasing research hotspots. By recognizing the most critical indicators (researchers, countries, research institutes, and journals of glutamate release in epilepsy research), the research hotspot of glutamate in epilepsy could help countries, scholars, and policymakers in this field enhance their understanding of the role of glutamate in epilepsy and make decisions.

Neuroprotective and anti-epileptic potentials of genus Artemisia L

The Genus Artemisia L. is one of the largest genera in the Asteraceae family growing wild over in Europe, North America, and Central Asia and has been widely used in folk medicine for the treatment of various ailments. Phytochemical and psychopharmacological studies indicated that the genus Artemisia extracts contain various antioxidant and anti-inflammatory compounds and possess antioxidant, anti-inflammatory, antimicrobial, antimalarial, and antitumor activity. Recently, increasing experimental studies demonstrated that many Artemisia extracts offer a great antiepileptic potential, which was attributed to their bioactive components via various mechanisms of action. However, detailed literature on the antiepileptic properties of the genus Artemisia and its mechanism of action is segregated. In this review, we tried to gather the detailed neuroprotective and antiepileptic properties of the genus Artemisia and its possible underlying mechanisms. In this respect, 63 articles were identified in the PubMed and Google scholars databases, from which 18 studies were examined based on the pharmacological use of the genus Artemisia species in epilepsy. The genus Artemisia extracts have been reported to possess antioxidant, anti-inflammatory, neurotransmitter-modulating, anti-apoptotic, anticonvulsant, and pro-cognitive properties by modulating oxidative stress caused by mitochondrial ROS production and an imbalance of antioxidant enzymes, by protecting mitochondrial membrane potential required for ATP production, by upregulating GABA-A receptor and nACh receptor activities, and by interfering with various anti-inflammatory and anti-apoptotic signaling pathways, such as mitochondrial apoptosis pathway, ERK/CREB/Bcl-2 pathway and Nrf2 pathway. This review provides detailed information about some species of the genus Artemisia as potential antiepileptic agents. Hence, we recommend further investigations on the purification and identification of the most biological effective compounds of Artemisia and the mechanisms of their action to cure epilepsy and other neurological diseases.

Experimental and Clinical Biomarkers for Progressive Evaluation of Neuropathology and Therapeutic Interventions for Acute and Chronic Neurological Disorders

This article describes commonly used experimental and clinical biomarkers of neuronal injury and neurodegeneration for the evaluation of neuropathology and monitoring of therapeutic interventions. Biomarkers are vital for diagnostics of brain disease and therapeutic monitoring. A biomarker can be objectively measured and evaluated as a proxy indicator for the pathophysiological process or response to therapeutic interventions. There are complex hurdles in understanding the molecular pathophysiology of neurological disorders and the ability to diagnose them at initial stages. Novel biomarkers for neurological diseases may surpass these issues, especially for early identification of disease risk. Validated biomarkers can measure the severity and progression of both acute neuronal injury and chronic neurological diseases such as epilepsy, migraine, Alzheimer's disease, Parkinson's disease, Huntington's disease, traumatic brain injury, amyotrophic lateral sclerosis, multiple sclerosis, and other brain diseases. Biomarkers are deployed to study progression and response to treatment, including noninvasive imaging tools for both acute and chronic brain conditions. Neuronal biomarkers are classified into four core subtypes: blood-based, immunohistochemical-based, neuroimaging-based, and electrophysiological biomarkers. Neuronal conditions have progressive stages, such as acute injury, inflammation, neurodegeneration, and neurogenesis, which can serve as indices of pathological status. Biomarkers are critical for the targeted identification of specific molecules, cells, tissues, or proteins that dramatically alter throughout the progression of brain conditions. There has been tremendous progress with biomarkers in acute conditions and chronic diseases affecting the central nervous system.

Understanding Acquired Brain Injury: A Review

Any type of brain injury that transpires post-birth is referred to as Acquired Brain Injury (ABI). In general, ABI does not result from congenital disorders, degenerative diseases, or by brain trauma at birth. Although the human brain is protected from the external world by layers of tissues and bone, floating in nutrient-rich cerebrospinal fluid (CSF); it remains susceptible to harm and impairment. Brain damage resulting from ABI leads to changes in the normal neuronal tissue activity and/or structure in one or multiple areas of the brain, which can often affect normal brain functions. Impairment sustained from an ABI can last anywhere from days to a lifetime depending on the severity of the injury; however, many patients face trouble integrating themselves back into the community due to possible psychological and physiological outcomes. In this review, we discuss ABI pathologies, their types, and cellular mechanisms and summarize the therapeutic approaches for a better understanding of the subject and to create awareness among the public.

Molecular Mechanisms of Epilepsy: The Role of the Chloride Transporter KCC2

Epilepsy is a neurological disease characterized by abnormal or synchronous brain activity causing seizures, which may produce convulsions, minor physical signs, or a combination of symptoms. These disorders affect approximately 65 million people worldwide, from all ages and genders. Seizures apart, epileptic patients present a high risk to develop neuropsychological comorbidities such as cognitive deficits, emotional disturbance, and psychiatric disorders, which severely impair quality of life. Currently, the treatment for epilepsy includes the administration of drugs or surgery, but about 30% of the patients treated with antiepileptic drugs develop time-dependent pharmacoresistence. Therefore, further investigation about epilepsy and its causes is needed to find new pharmacological targets and innovative therapeutic strategies. Pharmacoresistance is associated to changes in neuronal plasticity and alterations of GABA_A receptor-mediated neurotransmission. The downregulation of GABA inhibitory activity may arise from a positive shift in GABA_A receptor reversal potential, due to an alteration in chloride homeostasis. In this paper, we review the contribution of K⁺-Cl^--cotransporter (KCC2) to the alterations in the Cl^- gradient observed in epileptic condition, and how these alterations are coupled to the increase in the excitability.

A Comprehensive and Advanced Mouse Model of Post-Traumatic Epilepsy with Robust Spontaneous Recurrent Seizures

Traumatic brain injury (TBI) is a leading cause of epilepsy in military persons and civilians. Spontaneous recurrent seizures (SRSs) occur in the months or years following the injury, which is commonly referred to as post-traumatic epilepsy (PTE). Currently, there is no effective treatment or cure for PTE; therefore, there is a critical need to develop animal models to help further understand and assess mechanisms and interventions related to TBI-induced epilepsy. Despite many attempts to induce PTE in animals, success has been limited due to a lack of consistent SRSs after TBI. We present a comprehensive protocol to induce PTE after contusion brain injury in mice, which exhibit robust SRSs along with neurodegeneration and neuroinflammation. This article provides a complete set of protocols for injury, outcomes, troubleshooting, and data analysis. Our broad profiling of a TBI mouse reveals features of progressive, long-lasting epileptic activity, hippocampal sclerosis, and comorbid mood and memory deficits. Overall, the PTE mouse shows striking consistency in recapitulating major hallmark features of human PTE. This mouse model will be helpful in assessing mechanisms of and interventions for TBI-induced epileptogenesis, epilepsy, and neuropsychiatric dysfunction. © 2022 Wiley Periodicals LLC. Basic Protocol 1: Inducing controlled cortical impact injuries Support Protocol: Creating the custom domed camp Basic Protocol 2: Recording long-term video-EEG signals Basic Protocol 3: Analyzing video-EEG recordings.

TGF-β as a Key Modulator of Astrocyte Reactivity: Disease Relevance and Therapeutic Implications

Astrocytes are essential for normal brain development and functioning. They respond to brain injury and disease through a process referred to as reactive astrogliosis, where the reactivity is highly heterogenous and context-dependent. Reactive astrocytes are active contributors to brain pathology and can exert beneficial, detrimental, or mixed effects following brain insults. Transforming growth factor-β (TGF-β) has been identified as one of the key factors regulating astrocyte reactivity. The genetic and pharmacological manipulation of the TGF-β signaling pathway in animal models of central nervous system (CNS) injury and disease alters pathological and functional outcomes. This review aims to provide recent understanding regarding astrocyte reactivity and TGF-β signaling in brain injury, aging, and neurodegeneration. Further, it explores how TGF-β signaling modulates astrocyte reactivity and function in the context of CNS disease and injury.

Anticholinergics: A potential option for preventing posttraumatic epilepsy

Interest in the use of anticholinergics to prevent the development of epilepsy after traumatic brain injury (TBI) has grown since recent basic studies have shown their effectiveness in modifying the epileptogenic process. These studies demonstrated that treatment with anticholinergics, in the acute phase after brain injury, decreases seizure frequency, and severity, and the number of spontaneous recurrent seizures (SRS). Therefore, anticholinergics may reduce the risk of developing posttraumatic epilepsy (PTE). In this brief review, we summarize the role of the cholinergic system in epilepsy and the key findings from using anticholinergic drugs to prevent PTE in animal models and new clinical trial protocols. Furthermore, we discuss why treatment with anticholinergics is more likely to prevent PTE than treatment for other epilepsies.

Contusion brain damage in mice for modelling of post-traumatic epilepsy with contralateral hippocampus sclerosis: Comprehensive and longitudinal characterization of spontaneous seizures, neuropathology, and neuropsychiatric comorbidities

Traumatic brain injury (TBI) is a leading cause of acquired epilepsy referred to as post-traumatic epilepsy (PTE), characterized by spontaneous recurrent seizures (SRS) that start in the months or years following TBI. There is a critical need to develop small animal models for advancing the neurotherapeutics of PTE, which accounts for 20% of all acquired epilepsy cases. Despite many previous attempts, there are few PTE models with demonstrated consistency or longitudinal incidence of SRS, a critical feature for creating models for investigation of novel therapeutics for preventing PTE. Over the past few years, we have made in-depth updates and several advances to our mouse model of TBI in which SRS consistently occurs upon 24/7 monitoring for 4 months. Here, we show that an advanced cortical contusion damage in mice elicits a chronic state of PTE with SRS and robust epileptiform activity, along with cognitive comorbidities. We observed SRS in 33% and 87% of moderate and severe injury cohorts, respectively. Though incidence was higher in the severe cohort, moderate injury elicited a robust epileptogenesis. Progressive neuronal damage, neurodegeneration, and inflammation signals were evident in many brain regions; comorbid behavior and cognitive deficits were observed for up to 4-months. SRS onset was correlated with the inception of interneuron loss after TBI. Contralateral hippocampal sclerosis was unique and well correlated with SRS, confirming a potential network basis for epileptogenesis. Collectively, this mouse model exhibits a number of hallmark TBI sequelae reminiscent of human PTE. This model provides a vital tool for probing molecular pathological mechanisms and therapeutic interventions for post-traumatic epileptogenesis. SIGNIFICANCE STATEMENT: TBI is a leading cause of post-traumatic epilepsy (PTE). Despite many attempts to create PTE in animals, success has been limited due to a lack of consistent spontaneous "epileptic" seizures after TBI. We present a comprehensive phenotype of PTE after contusion brain injury in mice, which exhibits robust spontaneous seizures along with neuronal loss, inflammation, and cognitive dysfunction. Our broad profiling of a TBI mouse reveals features of progressive, long-lasting epileptic activity, unique contralateral hippocampal sclerosis, and comorbid mood and memory deficits. The PTE mouse shows a striking consistency in recapitulating major pathological sequelae of human PTE. This mouse model will be helpful in assessing mechanisms and interventions for TBI-induced epilepsy and mood dysfunction.