Targeting oxidative stress improves disease outcomes in a rat model of acquired epilepsy

Mitochondrial dysfunction in chronic neuroinflammatory diseases (Review)

Chronic neuroinflammation serves a key role in the onset and progression of neurodegenerative disorders. Mitochondria serve as central regulators of neuroinflammation. In addition to providing energy to cells, mitochondria also participate in the immunoinflammatory response of neurodegenerative disorders including Alzheimer's disease, Parkinson's disease, multiple sclerosis and epilepsy, by regulating processes such as cell death and inflammasome activation. Under inflammatory conditions, mitochondrial oxidative stress, epigenetics, mitochondrial dynamics and calcium homeostasis imbalance may serve as underlying regulatory mechanisms for these diseases. Therefore, investigating mechanisms related to mitochondrial dysfunction may result in therapeutic strategies against chronic neuroinflammation and neurodegeneration. The present review summarizes the mechanisms of mitochondria in chronic neuroinflammatory diseases and the current treatment approaches that target mitochondrial dysfunction in these diseases.

Identification of an epilepsy-linked gut microbiota signature in a pediatric rat model of acquired epilepsy

A dysfunctional gut microbiota-brain axis is emerging as a potential pathogenic mechanism in epilepsy, particularly in pediatric forms of epilepsy. To add new insights into gut-related changes in acquired epilepsy that develops early in life, we used a multi-omics approach in a rat model with a 56% incidence of epilepsy. The presence of spontaneous seizures was assessed in adult rats (n = 46) 5 months after status epilepticus induced by intra-amygdala kainate at postnatal day 13, by 2 weeks (24/7) ECoG monitoring. Twenty-six rats developed epilepsy (Epi) while the remaining 20 rats (No-Epi) did not show spontaneous seizures. At the end of ECoG monitoring, all rats and their sham controls (n = 20) were sacrificed for quantitative histopathological and immunohistochemical analyses of the gut structure, glia and macrophages, as well as RTqPCR analysis of inflammation/oxidative stress markers. By comparing Epi, No-Epi rats, and sham controls, we found structural, cellular, and molecular alterations reflecting a dysfunctional gut, which were specifically associated with epilepsy. In particular, the villus height-to-crypt depth ratio and number of Goblet cells were reduced in the duodenum of Epi rats vs both No-Epi rats and sham controls (p < 0.01). Villus height and crypt depth in the duodenum and jejunum (p < 0.01) were increased in No-Epi vs both Epi and sham controls. We also detected enhanced Iba1-positive macrophages, together with increased IL1b and NFE2L2 transcripts and TNF protein, in the small intestine of Epi vs both No-Epi and sham control rats (p < 0.01), denoting the presence of inflammation and oxidative stress. Astroglial GFAP-immunostaining was similar in all experimental groups. Metagenomic analysis in the feces collected 5 months after status epilepticus showed that the ratio of two dominant phyla (Bacteroidota-to-Firmicutes) was similarly increased in Epi and No-Epi rats vs sham control rats. Notably, the relative abundance of families, genera, and species associated with SCFA production differed in Epi vs No-Epi rats, describing a bacterial imprint associated with epilepsy. Furthermore, Epi rats showed a blood metabolic signature characterized by changes in lipid metabolism compared to both No-Epi and sham control rats. Our study provides new evidence of long-term gut alterations, along with microbiota-related metabolic changes, occurring specifically in rats that develop epilepsy after brain injury early in life.

Pharmacological elevation of glutathione inhibits status epilepticus-induced neuroinflammation and oxidative injury

Glutathione (GSH) is a major endogenous antioxidant, and its depletion has been observed in several brain diseases including epilepsy. Previous studies in our laboratory have shown that dimercaprol (DMP) can elevate GSH via post-translational activation of glutamate cysteine ligase (GCL), the rate limiting GSH biosynthetic enzyme and inhibit neuroinflammation in vitro. Here we determined 1) the role of cysteamine as a new mechanism by which DMP increases GSH biosynthesis and 2) its ability to inhibit neuroinflammation and neuronal injury in the rat kainate model of epilepsy. DMP depleted cysteamine in a time- and concentration-dependent manner in a cell free system. To guide the in vivo administration of DMP, its pharmacokinetic profile was determined in the plasma, liver, and brain. The results confirmed DMP's ability to cross the blood-brain-barrier. Treatment of rats with DMP (30 mg/kg) depleted cysteamine in the liver and hippocampus that was associated with increased GCL activity in these tissues. GSH levels were significantly increased (20 %) in the hippocampus 1 h after 30 mg/kg DMP administration. Following DMP (30 mg/kg) administration once daily, a marked attenuation of GSH depletion was seen in the SE model. SE-induced inflammatory markers including cytokine release, microglial activation, and neuronal death were significantly attenuated in the hippocampus with DMP treatment. Taken together, these results highlight the importance of restoring redox status with rescue of GSH depletion by DMP in post epileptogenic insults.

The effect of ferroptosis-related mitochondrial dysfunction in the development of temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is the most common form of epileptic syndrome. It has been established that due to its complex pathogenesis, a considerable proportion of TLE patients often progress to drug-resistant epilepsy. Ferroptosis has emerged as an important neuronal death mechanism in TLE, which is primarily influenced by lipid accumulation and oxidative stress. In previous studies of ferroptosis, more attention has been focused on the impact of changes in the levels of proteins related to the redox equilibrium and signaling pathways on epileptic seizures. However, it is worth noting that the oxidative-reduction changes in different organelles may have different pathophysiological significance in the process of ferroptosis-related diseases. Mitochondria, as a key organelle involved in ferroptosis, its structural damage and functional impairment can lead to energy metabolism disorders and disruption of the excitatory inhibitory balance, significantly increasing the susceptibility to epileptic seizures. Therefore, secondary mitochondrial dysfunction in the process of ferroptosis could play a crucial role in TLE pathogenesis. This review focuses on ferroptosis and mitochondria, discussing the pathogenic role of ferroptosis-related mitochondrial dysfunction in TLE, thus aiming to provide novel insights and potential implications of ferroptosis-related secondary mitochondrial dysfunction in epileptic seizures and to offer new insights for the precise exploration of ferroptosis-related therapeutic targets for TLE patients.

Current understanding and future directions of cruciferous vegetables and their phytochemicals to combat neurological diseases

Neurological disorders incidences are increasing drastically due to complex pathophysiology, and the nonavailability of disease-modifying agents. Several attempts have been made to identify new potential chemicals to combat these neurological abnormalities. At present, complete abolishment of neurological diseases is not attainable except for symptomatic relief. However, dietary recommendations to help brain development or improvement have increased over the years. In recent times, cruciferous vegetables and their phytochemicals have been identified from preclinical and clinical investigations as potential neuroprotective agents. The present review highlights the beneficial effects and molecular mechanisms of phytochemicals such as indole-3-carbinol, diindolylmethane, sulforaphane, kaempferol, selenium, lutein, zeaxanthin, and vitamins of cruciferous vegetables against neurological diseases including Parkinson's disease, Alzheimer's disease, stroke, Huntington's disease, autism spectra disorders, anxiety, depression, and pain. Most of these cruciferous phytochemicals protect the brain by eliciting antioxidant, anti-inflammatory, and antiapoptotic properties. Regular dietary intake of cruciferous vegetables may benefit the prevention and treatment of neurological diseases. The present review suggests that there is a lacuna in identifying the clinical efficacy of these phytochemicals. Therefore, high-quality future studies should firmly establish the efficacy of the above-mentioned cruciferous phytochemicals in clinical settings.

Polysaccharide-rich extract of Genipa americana leaves protects seizures and oxidative stress in the mice model of pentylenetetrazole-induced epilepsy

Plant polysaccharides have biological activities in the brain and those obtained from Genipa americana leaves present antioxidant and anticonvulsant effects in the mice model of pentylenetetrazole (PTZ)-induced acute seizures. This study aimed to evaluate the polysaccharide-rich extract of Genipa americana leaves (PRE-Ga) in the models of acute seizures and chronic epilepsy (kindling) induced by PTZ. In the acute seizure model, male Swiss mice (25-35 g) received PRE-Ga (1 or 9 mg/kg; intraperitoneal- IP), alone or associated with diazepam (0.01 mg/kg), 30 min before induction of seizures with PTZ (70 mg/kg; IP). In the chronic epilepsy model, seizures were induced by PTZ (40 mg/kg) 30 min after treatment and in alternated days up to 30 days and evaluated by video. Brain areas (prefrontal cortex, hippocampus, striatum) were assessed for inflammatory and oxidative stress markers. Diazepam associated to PRE-Ga (9 mg/kg; i.p.) increased the latency of seizures in acute (222.4 ± 47.57 vs. saline: 62.00 ± 4.709 s) and chronic models (6.267 ± 0.502 vs. saline: 4.067 ± 0.407 s). In hippocampus, PRE-Ga (9 mg/kg) inhibited TNF-α (105.9 ± 5.38 vs. PTZ: 133.5 ± 7.62 pmol/g) and malondialdehyde (MDA) (473.6 ± 60.51) in the chronic model. PTZ increased glial fibrillar acid proteins (GFAP) and Iba-1 in hippocampus, which was reversed by PRE-Ga (GFAP: 1.9 ± 0.23 vs PTZ: 3.1 ± 1.3 and Iba-1: 2.2 ± 0.8 vs PTZ: 3.2 ± 1.4). PRE-Ga presents neuroprotector effect in the mice model of epilepsy induced by pentylenetetrazole reducing seizures, gliosis, inflammatory cytokines and oxidative stress.

Novel Catalytic Antioxidant Formulation Decreases Oxidative Stress, Neuroinflammation and Cognitive Dysfunction in a Model of Nerve Agent Intoxication

Reactive oxygen species have an emerging role in the pathologic consequences of status epilepticus. We have previously demonstrated the efficacy of a water-for-injection formulation of the meso-porphyrin catalytic antioxidant, manganese (III) meso-tetrakis (N-N-diethylimidazole) porphyrin (AEOL10150) against oxidative stress, neuroinflammation, and neuronal death initiated by kainic acid, pilocarpine, diisopropylflurophosphate (DFP), and soman. This previous dose and dosing strategy of AEOL10150 required smaller multiple daily injections, precluding our ability to test its efficacy against delayed consequences of nerve agent exposure such as neurodegeneration and cognitive dysfunction. Therefore, we developed formulations of AEOL10150 designed to deliver a larger dose once daily with improved brain pharmacodynamics. We examined four new formulations of AEOL10150 that resulted in 8 times higher subcutaneous dose with lower acute toxicity, slower absorption, longer half-life, and higher maximal plasma concentrations compared with our previous strategy. AEOL10150 brain levels exhibited improved pharmacodynamics over 24 hours with all four formulations. We tested a subcutaneous dose of 40 mg/kg AEOL10150 in two formulations (2% carboxymethyl cellulose and 4% polyethylene glycol-4000) in the DFP rat model, and both formulations exhibited significant protection against DFP-induced oxidative stress. Additionally, and in one formulation (4% polyethylene glycol-4000), AEOL10150 significantly protected against DFP-induced neuronal death, microglial activation, delayed memory impairment, and mortality. These results suggest that reformulation of AEOL10150 can attenuate acute and delayed outcomes of organophosphate neurotoxicity. SIGNIFICANCE STATEMENT: Reformulation of manganese (III) meso-tetrakis (N-N-diethylimidazole) porphyrin allowed higher tolerated doses of the compound with improved pharmacodynamics. Specifically, one new formulation allowed fewer daily doses and improvement in acute and delayed outcomes of organophosphate toxicity.

Exploring the neuroprotective potential of antimicrobial peptides from Dinoponera quadriceps venom against pentylenetetrazole-induced seizures in vivo

Epilepsy affects around 50 million people worldwide and 30% of patients have difficulty controlling the disease. The search for substances that can fill the existing gaps in the treatment of epilepsy is of great importance. Arthropod venoms are promising sources for this purpose due to the presence of small peptides that modulate the activity of ion channels and neuron receptors. The aim of this study was to investigate dinoponeratoxins from the Dinoponera quadriceps ant venom (M-PONTX-Dq3a, M-PONTX-Dq3b and M-PONTX-Dq3c) as potential anticonvulsants. We evaluated them in a seizure model induced by pentylenetetrazole (PTZ) in male swiss mice. Interestingly, intraperitoneal treatment with each peptide increased the time until the first seizure and the percentage of survival, with M-PONTX-Dq3b showing the best results. M-PONTX-Dq3a was discarded due to the appearance of some signs of toxicity with the increase in malondialdehyde (MDA) levels in the striatum. Both, M-PONTX-Dq3b and M-PONTX-Dq3c decreased iNOS and TNF-α in the hippocampus. Notably, M-PONTX-Dq3c treatment decreased the levels of MDA and nitrite in the cortex and hippocampus. Our results indicate that, M-PONTX-Dq3b and M-PONTX-Dq3c have anticonvulsant activity and exhibit anti-inflammatory effects in epilepsy, offering new perspectives for biopharmaceutical development.

Neuroinflammation in epileptogenesis: from pathophysiology to therapeutic strategies

Epilepsy is a group of enduring neurological disorder characterized by spontaneous and recurrent seizures with heterogeneous etiology, clinical expression, severity, and prognosis. Growing body of research investigates that epileptic seizures are originated from neuronal synchronized and excessive electrical activity. However, the underlying molecular mechanisms of epileptogenesis have not yet been fully elucidated and 30% of epileptic patients still are resistant to the currently available pharmacological treatments with recurrent seizures throughout life. Over the past two decades years accumulated evidences provide strong support to the hypothesis that neuroinflammation, including microglia and astrocytes activation, a cascade of inflammatory mediator releasing, and peripheral immune cells infiltration from blood into brain, is associated with epileptogenesis. Meanwhile, an increasing body of preclinical researches reveal that the anti-inflammatory therapeutics targeting crucial inflammatory components are effective and promising in the treatment of epilepsy. The aim of the present study is to highlight the current understanding of the potential neuroinflammatory mechanisms in epileptogenesis and the potential therapeutic targets against epileptic seizures.

Metabolomics of cerebrospinal fluid reveals prognostic biomarkers in pediatric status epilepticus

AIMS

Status epilepticus (SE) is the most common neurological emergency in pediatric patients. This study aimed to screen for prognostic biomarkers of SE in the cerebrospinal fluid (CSF) using metabolomics.

METHODS

Ultra-performance liquid chromatography quadrupole time-of-flight tandem mass spectrometry (UPLC-QTOF-MS) was conducted to identify prognostic biomarkers in CSF metabolomics by comparing the poor outcome group (N = 13) with the good outcome group (N = 15) of children with SE. Differentially expressed metabolites were identified using Mann-Whitney U test corrected by Benjamini-Hochberg and partial least squares discriminant analysis (PLS-DA).

RESULTS

The PLS-DA model identified and validated significant metabolic differences between the poor and good outcome groups of children with SE (PLS-DA with R2 Y = 0.992 and Q2  = 0.798). A total of 49 prognosis-related metabolites were identified. Of these metabolites, 20 including glutamyl-glutamine, 3-iodothyronamine, and L-fucose had an area under the curve (AUC) ≥ 80% in prognostic prediction of SE. The logistic regression model combining glutamyl-glutamine and 3-iodothyronamine produced an AUC value of 0.976, with a sensitivity of 0.863 and specificity of 0.956. Pathway analysis revealed that dysregulation of the citrate cycle (TCA) and arginine biosynthesis may contribute to poor SE prognosis.

CONCLUSIONS

This study highlighted the prognosis-related metabolomic disturbances in the CSF of children with SE and identified potential prognostic biomarkers. A prognostic prediction model combining glutamyl-glutamine and 3-iodothyronamine with high predictive value was established.

NOX-induced oxidative stress is a primary trigger of major neurodegenerative disorders

Neurodegenerative diseases (NDDs) causing cognitive impairment and dementia are difficult to treat due to the lack of understanding of primary initiating factors. Meanwhile, major sporadic NDDs share many risk factors and exhibit similar pathologies in their early stages, indicating the existence of common initiation pathways. Glucose hypometabolism associated with oxidative stress is one such primary, early and shared pathology, and a likely major cause of detrimental disease-associated cascades; targeting this common pathology may therefore be an effective preventative strategy for most sporadic NDDs. However, its exact cause and trigger remain unclear. Recent research suggests that early oxidative stress caused by NADPH oxidase (NOX) activation is a shared initiating mechanism among major sporadic NDDs and could prove to be the long-sought ubiquitous NDD trigger. We focus on two major NDDs - Alzheimer's disease (AD) and Parkinson's disease (PD), as well as on acquired epilepsy which is an increasingly recognized comorbidity in NDDs. We also discuss available data suggesting the relevance of the proposed mechanisms to other NDDs. We delve into the commonalities among these NDDs in neuroinflammation and NOX involvement to identify potential therapeutic targets and gain a deeper understanding of the underlying causes of NDDs.

Postictal hypoxia involves reactive oxygen species and is ameliorated by chronic mitochondrial uncoupling

Prolonged severe hypoxia follows brief seizures and represents a mechanism underlying several negative postictal manifestations without interventions. Approximately 50% of the postictal hypoxia phenomenon can be accounted for by arteriole vasoconstriction. What accounts for the rest of the drop in unbound oxygen is unclear. Here, we determined the effect of pharmacological modulation of mitochondrial function on tissue oxygenation in the hippocampus of rats after repeatedly evoked seizures. Rats were treated with mitochondrial uncoupler 2,4 dinitrophenol (DNP) or antioxidants. Oxygen profiles were recorded using a chronically implanted oxygen-sensing probe, before, during, and after seizure induction. Mitochondrial function and redox tone were measured using in vitro mitochondrial assays and immunohistochemistry. Postictal cognitive impairment was assessed using the novel object recognition task. Mild mitochondrial uncoupling by DNP raised hippocampal oxygen tension and ameliorated postictal hypoxia. Chronic DNP also lowered mitochondrial oxygen-derived reactive species and oxidative stress in the hippocampus during postictal hypoxia. Uncoupling the mitochondria exerts therapeutic benefits on postictal cognitive dysfunction. Finally, antioxidants do not affect postictal hypoxia, but protect the brain from associated cognitive deficits. We provided evidence for a metabolic component of the prolonged oxygen deprivation that follow seizures and its pathological sequelae. Furthermore, we identified a molecular underpinning of this metabolic component, which involves excessive oxygen conversion into reactive species. Mild mitochondrial uncoupling may be a potential therapeutic strategy to treat the postictal state where seizure control is absent or poor.

NCBP1 Improves Cognitive Function in Mice by Reducing Oxidative Stress, Neuronal Loss, and Glial Activation After Status Epilepticus

Status epilepticus (SE) is a severe manifestation of epilepsy which can cause neurologic injury and death. This study aimed to identify key proteins involved in the pathogenesis of epilepsy and find a potential drug target for SE treatment. Tandem mass tag (TMT)-based quantitative proteomic analysis was applied to screen differentially expressed proteins (DEPs) in epilepsy. The adeno-associated virus was employed to overexpress candidate DEP in mice, and kainic acid (KA) was used to generate a mouse model of epilepsy. Then histopathological examination of the hippocampal tissue was performed, and the inflammatory factors levels in serum and hippocampus were measured. The IP-MS analysis was carried out to identify the interacting protein of nuclear cap-binding protein 1 (NCBP1). The results were that NCBP1 was downregulated in the epileptic hippocampus. NCBP1 overexpression alleviated KA-induced cognitive impairment in mice and reduced the apoptosis and damage of hippocampal neurons. Additionally, overexpressed NCBP1 increased the expression of NeuN and reduced the expression of GFAP and IBA-1 in the hippocampus of the mice. Further study indicated that NCBP1 overexpression inhibited the expression of IL-6, IL-1β, and IFN-γ in serum and hippocampus as well as MDA and LDH in the hippocampus, whereas it increased the SOD levels, suggesting that overexpression of NCBP1 could diminish KA-induced inflammatory responses and oxidative stress. The IP-MS analysis identified that ELAVL4 was the NCBP1-interacting protein. In conclusion, this finding suggests that NCBP1 may potentially serve as a drug target for the treatment of epilepsy.

Increasing glutathione levels by a novel posttranslational mechanism inhibits neuronal hyperexcitability

Glutathione (GSH) depletion, and impaired redox homeostasis have been observed in experimental animal models and patients with epilepsy. Pleiotropic strategies that elevate GSH levels via transcriptional regulation have been shown to significantly decrease oxidative stress and seizure frequency, increase seizure threshold, and rescue certain cognitive deficits. Whether elevation of GSH per se alters neuronal hyperexcitability remains unanswered. We previously showed that thiols such as dimercaprol (DMP) elevate GSH via post-translational activation of glutamate cysteine ligase (GCL), the rate limiting GSH biosynthetic enzyme. Here, we asked if elevation of cellular GSH by DMP altered neuronal hyperexcitability in-vitro and in-vivo. Treatment of primary neuronal-glial cerebrocortical cultures with DMP elevated GSH and inhibited a voltage-gated potassium channel blocker (4-aminopyridine, 4AP) induced neuronal hyperexcitability. DMP increased GSH in wildtype (WT) zebrafish larvae and significantly attenuated convulsant pentylenetetrazol (PTZ)-induced acute 'seizure-like' swim behavior. DMP treatment increased GSH and inhibited convulsive, spontaneous 'seizure-like' swim behavior in the Dravet Syndrome (DS) zebrafish larvae (scn1Lab). Furthermore, DMP treatment significantly decreased spontaneous electrographic seizures and associated seizure parameters in scn1Lab zebrafish larvae. We investigated the role of the redox-sensitive mammalian target of rapamycin (mTOR) pathway due to the presence of several cysteine-rich proteins and their involvement in regulating neuronal excitability. Treatment of primary neuronal-glial cerebrocortical cultures with 4AP or l-buthionine-(S,R)-sulfoximine (BSO), an irreversible inhibitor of GSH biosynthesis, significantly increased mTOR complex I (mTORC1) activity which was rescued by pre-treatment with DMP. Furthermore, BSO-mediated GSH depletion oxidatively modified the tuberous sclerosis protein complex (TSC) consisting of hamartin (TSC1), tuberin (TSC2), and TBC1 domain family member 7 (TBC1D7) which are critical negative regulators of mTORC1. In summary, our results suggest that DMP-mediated GSH elevation by a novel post-translational mechanism can inhibit neuronal hyperexcitability both in-vitro and in-vivo and a plausible link is the redox sensitive mTORC1 pathway.

Preferential pruning of inhibitory synapses by microglia contributes to alteration of the balance between excitatory and inhibitory synapses in the hippocampus in temporal lobe epilepsy

BACKGROUND

A consensus has formed that neural circuits in the brain underlie the pathogenesis of temporal lobe epilepsy (TLE). In particular, the synaptic excitation/inhibition balance (E/I balance) has been implicated in shifting towards elevated excitation during the development of TLE.

METHODS

Sprague Dawley (SD) rats were intraperitoneally subjected to kainic acid (KA) to generate a model of TLE. Next, electroencephalography (EEG) recording was applied to verify the stability and detectability of spontaneous recurrent seizures (SRS) in rats. Moreover, hippocampal slices from rats and patients with mesial temporal lobe epilepsy (mTLE) were assessed using immunofluorescence to determine the alterations of excitatory and inhibitory synapses and microglial phagocytosis.

RESULTS

We found that KA induced stable SRSs 14 days after status epilepticus (SE) onset. Furthermore, we discovered a continuous increase in excitatory synapses during epileptogenesis, where the total area of vesicular glutamate transporter 1 (vGluT1) rose considerably in the stratum radiatum (SR) of cornu ammonis 1 (CA1), the stratum lucidum (SL) of CA3, and the polymorphic layer (PML) of the dentate gyrus (DG). In contrast, inhibitory synapses decreased significantly, with the total area of glutamate decarboxylase 65 (GAD65) in the SL and PML diminishing enormously. Moreover, microglia conducted active synaptic phagocytosis after the formation of SRSs, especially in the SL and PML. Finally, microglia preferentially pruned inhibitory synapses during recurrent seizures in both rat and human hippocampal slices, which contributed to the synaptic alteration in hippocampal subregions.

CONCLUSIONS

Our findings elaborately characterize the alteration of neural circuits and demonstrate the selectivity of synaptic phagocytosis mediated by microglia in TLE, which could strengthen the comprehension of the pathogenesis of TLE and inspire potential therapeutic targets for epilepsy treatment.

The standardized extract of Centella asiatica L. Urb attenuates the convulsant effect induced by lithium/pilocarpine without affecting biochemical and haematological parameters in rats

BACKGROUND

Status epilepticus (SE) is a type of epileptic activity characterized by a failure of the inhibitory mechanisms that limit seizures, which are mainly regulated by the GABAergic system. This imbalance increases glutamatergic neurotransmission and consequently produces epileptic activity. It is also associated with oxidative stress due to an imbalance between reactive oxygen species (ROS) and antioxidant defences. Unfortunately, long-term treatment with anti-epileptic drugs (AEDs) may produce hepatotoxicity, nephrotoxicity, and haematological alterations. In this way, some secondary metabolites of plants have been used to ameliorate the deterioration of nervous system disorders through their antioxidant properties, in addition to their anticonvulsant effects. An example is Centella asiatica, a plant noted to have a reputed neuroprotective effect related to its antioxidant activity. However, similar to conventional drugs, natural molecules may produce side effects when consumed in high doses, which could occur with Centella asiatica. Therefore, we aimed to evaluate the effect of a standardized extract of Centella asiatica L. Urb with tested anticonvulsant activity on biochemical and haematological parameters in rats subjected to lithium/pilocarpine-induced seizures.

METHODS

Twenty-eight adult male Wistar rats were randomly divided into four groups (n = 7 each): vehicle (purified water), Centella asiatica (200 and 400 mg/kg), and carbamazepine (CBZ) (300 mg/kg) as a pharmacological control of anticonvulsant activity. Treatments were administered orally every 24 h for 35 consecutive days. On Day 36, SE was induced using the lithium/pilocarpine model (3 mEq/kg, i.p. and 30 mg/kg s.c., respectively), and the behavioural and biochemical effects were evaluated.

RESULTS

Centella asiatica 400 mg/kg increased the latency to the first generalized seizure and SE onset and significantly reduced the time to the first generalized seizure compared to values in the vehicle group. Biochemical parameters, i.e., haematic cytometry, blood chemistry, and liver function tests, showed no significant differences among the different treatments.

CONCLUSION

The dose of Centella asiatica that produces anticonvulsant activity in the lithium/pilocarpine model devoid of hepatotoxicity, nephrotoxicity, and alterations in haematological parameters suggests that the standardized extract of this plant could be of utility in the development of new safe therapies for the treatment of convulsions associated with epilepsy.

Repeated episodes of postictal hypoxia are a mechanism for interictal cognitive impairments

Comorbidities during the period between seizures present a significant challenge for individuals with epilepsy. Despite their clinical relevance, the pathophysiology of the interictal symptomatology is largely unknown. Postictal severe hypoxia (PIH) in those brain regions participating in the seizure has been indicated as a mechanism underlying several negative postictal manifestations. It is unknown how repeated episodes of PIH affect interictal symptoms in epilepsy. Using a rat model, we observed that repeated seizures consistently induced episodes of PIH that become increasingly severe with each seizure occurrence. Additionally, recurrent seizure activity led to decreased levels of oxygen in the hippocampus during the interictal period. However, these reductions were prevented when we repeatedly blocked PIH using either the COX-inhibitor acetaminophen or the L-type calcium channel antagonist nifedipine. Moreover, we found that interictal cognitive deficits caused by seizures were completely alleviated by repeated attenuation of PIH events. Lastly, mitochondrial dysfunction may contribute to the observed pathological outcomes during the interictal period. These findings provide evidence that seizure-induced hypoxia may play a crucial role in several aspects of epilepsy. Consequently, developing and implementing treatments that specifically target and prevent PIH could potentially offer significant benefits for individuals with refractory epilepsy.

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.

ECoG spiking activity and signal dimension are early predictive measures of epileptogenesis in a translational mouse model of traumatic brain injury

The latency between traumatic brain injury (TBI) and the onset of epilepsy (PTE) represents an opportunity for counteracting epileptogenesis. Antiepileptogenesis trials are hampered by the lack of sensitive biomarkers that allow to enrich patient's population at-risk for PTE. We aimed to assess whether specific ECoG signals predict PTE in a clinically relevant mouse model with ∼60% epilepsy incidence. TBI was provoked in adult CD1 male mice by controlled cortical impact on the left parieto-temporal cortex, then mice were implanted with two perilesional cortical screw electrodes and two similar electrodes in the hemisphere contralateral to the lesion site. Acute seizures and spikes/sharp waves were ECoG-recorded during 1 week post-TBI. These early ECoG events were analyzed according to PTE incidence as assessed by measuring spontaneous recurrent seizures (SRS) at 5 months post-TBI. We found that incidence, number and duration of acute seizures during 3 days post-TBI were similar in PTE mice and mice not developing epilepsy (No SRS mice). Control mice with cortical electrodes (naïve, n = 5) or with electrodes and craniotomy (sham, n = 5) exhibited acute seizures but did not develop epilepsy. The daily number of spikes/sharp waves at the perilesional electrodes was increased similarly in PTE (n = 15) and No SRS (n = 8) mice vs controls (p < 0.05, n = 10) from day 2 post-injury. Differently, the daily number of spikes/sharp waves at both contralateral electrodes showed a progressive increase in PTE mice vs No SRS and control mice. In particular, spikes number was higher in PTE vs No SRS mice (p < 0.05) at 6 and 7 days post-TBI, and this measure predicted epilepsy development with high accuracy (AUC = 0.77, p = 0.03; CI 0.5830-0.9670). The cut-off value was validated in an independent cohort of TBI mice (n = 12). The daily spike number at the contralateral electrodes showed a circadian distribution in PTE mice which was not observed in No SRS mice. Analysis of non-linear dynamics at each electrode site showed changes in dimensionality during 4 days post-TBI. This measure yielded the best discrimination between PTE and No SRS mice (p < 0.01) at the cortical electrodes contralateral to injury. Data show that epileptiform activity contralateral to the lesion site has the the highest predictive value for PTE in this model reinforcing the hypothesis that the hemisphere contralateral to the lesion core may drive epileptogenic networks after TBI.

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate.

Disease-modifying effects of a glial-targeted inducible nitric oxide synthase inhibitor (1400W) in mixed-sex cohorts of a rat soman (GD) model of epilepsy

BACKGROUND

Acute exposure to seizurogenic organophosphate (OP) nerve agents (OPNA) such as diisopropylfluorophosphate (DFP) or soman (GD), at high concentrations, induce immediate status epilepticus (SE), reactive gliosis, neurodegeneration, and epileptogenesis as a consequence. Medical countermeasures (MCMs-atropine, oximes, benzodiazepines), if administered in < 20 min of OPNA exposure, can control acute symptoms and mortality. However, MCMs alone are inadequate to prevent OPNA-induced brain injury and behavioral dysfunction in survivors. We have previously shown that OPNA exposure-induced SE increases the production of inducible nitric oxide synthase (iNOS) in glial cells in both short- and long- terms. Treating with a water soluble and highly selective iNOS inhibitor, 1400W, for 3 days significantly reduced OPNA-induced brain changes in those animals that had mild-moderate SE in the rat DFP model. However, such mitigating effects and the mechanisms of 1400W are unknown in a highly volatile nerve agent GD exposure.

METHODS

Mixed-sex cohort of adult Sprague Dawley rats were exposed to GD (132 μg/kg, s.c.) and immediately treated with atropine (2 mg/kg, i.m) and HI-6 (125 mg/kg, i.m.). Severity of seizures were quantified for an hour and treated with midazolam (3 mg/kg, i.m.). An hour post-midazolam, 1400W (20 mg/kg, i.m.) or vehicle was administered daily for 2 weeks. After behavioral testing and EEG acquisition, animals were euthanized at 3.5 months post-GD. Brains were processed for neuroinflammatory and neurodegeneration markers. Serum and CSF were used for nitrooxidative and proinflammatory cytokines assays.

RESULTS

We demonstrate a significant long-term (3.5 months post-soman) disease-modifying effect of 1400W in animals that had severe SE for > 20 min of continuous convulsive seizures. 1400W significantly reduced GD-induced motor and cognitive dysfunction; nitrooxidative stress (nitrite, ROS; increased GSH: GSSG); proinflammatory cytokines in the serum and some in the cerebrospinal fluid (CSF); epileptiform spikes and spontaneously recurring seizures (SRS) in males; reactive gliosis (GFAP + C3 and IBA1 + CD68-positive glia) as a measure of neuroinflammation, and neurodegeneration (especially parvalbumin-positive neurons) in some brain regions.

CONCLUSION

These findings demonstrate the long-term disease-modifying effects of a glial-targeted iNOS inhibitor, 1400W, in a rat GD model by modulating reactive gliosis, neurodegeneration (parvalbumin-positive neurons), and neuronal hyperexcitability.

Early preclinical plasma protein biomarkers of brain trauma are influenced by early seizures and levetiracetam

OBJECTIVE

We used the lateral fluid percussion injury (LFPI) model of moderate-to-severe traumatic brain injury (TBI) to identify early plasma biomarkers predicting injury, early post-traumatic seizures or neuromotor functional recovery (neuroscores), considering the effect of levetiracetam, which is commonly given after severe TBI.

METHODS

Adult male Sprague-Dawley rats underwent left parietal LFPI, received levetiracetam (200 mg/kg bolus, 200 mg/kg/day subcutaneously for 7 days [7d]) or vehicle post-LFPI, and were continuously video-EEG recorded (n = 14/group). Sham (craniotomy only, n = 6), and naïve controls (n = 10) were also used. Neuroscores and plasma collection were done at 2d or 7d post-LFPI or equivalent timepoints in sham/naïve. Plasma protein biomarker levels were determined by reverse phase protein microarray and classified according to injury severity (LFPI vs. sham/control), levetiracetam treatment, early seizures, and 2d-to-7d neuroscore recovery, using machine learning.

RESULTS

Low 2d plasma levels of Thr231 -phosphorylated tau protein (pTAU-Thr231 ) and S100B combined (ROC AUC = 0.7790) predicted prior craniotomy surgery (diagnostic biomarker). Levetiracetam-treated LFPI rats were differentiated from vehicle treated by the 2d-HMGB1, 2d-pTAU-Thr231 , and 2d-UCHL1 plasma levels combined (ROC AUC = 0.9394) (pharmacodynamic biomarker). Levetiracetam prevented the seizure effects on two biomarkers that predicted early seizures only among vehicle-treated LFPI rats: pTAU-Thr231 (ROC AUC = 1) and UCHL1 (ROC AUC = 0.8333) (prognostic biomarker of early seizures among vehicle-treated LFPI rats). Levetiracetam-resistant early seizures were predicted by high 2d-IFNγ plasma levels (ROC AUC = 0.8750) (response biomarker). 2d-to-7d neuroscore recovery was best predicted by higher 2d-S100B, lower 2d-HMGB1, and 2d-to-7d increase in HMGB1 or decrease in TNF (P < 0.05) (prognostic biomarkers).

SIGNIFICANCE

Antiseizure medications and early seizures need to be considered in the interpretation of early post-traumatic biomarkers.

Therapeutic Strategies to Ameliorate Neuronal Damage in Epilepsy by Regulating Oxidative Stress, Mitochondrial Dysfunction, and Neuroinflammation

Epilepsy is a central nervous system disorder involving spontaneous and recurring seizures that affects 50 million individuals globally. Because approximately one-third of patients with epilepsy do not respond to drug therapy, the development of new therapeutic strategies against epilepsy could be beneficial. Oxidative stress and mitochondrial dysfunction are frequently observed in epilepsy. Additionally, neuroinflammation is increasingly understood to contribute to the pathogenesis of epilepsy. Mitochondrial dysfunction is also recognized for its contributions to neuronal excitability and apoptosis, which can lead to neuronal loss in epilepsy. This review focuses on the roles of oxidative damage, mitochondrial dysfunction, NAPDH oxidase, the blood-brain barrier, excitotoxicity, and neuroinflammation in the development of epilepsy. We also review the therapies used to treat epilepsy and prevent seizures, including anti-seizure medications, anti-epileptic drugs, anti-inflammatory therapies, and antioxidant therapies. In addition, we review the use of neuromodulation and surgery in the treatment of epilepsy. Finally, we present the role of dietary and nutritional strategies in the management of epilepsy, including the ketogenic diet and the intake of vitamins, polyphenols, and flavonoids. By reviewing available interventions and research on the pathophysiology of epilepsy, this review points to areas of further development for therapies that can manage epilepsy.

Disease-Modifying Effects of a Glial-targeted Inducible Nitric Oxide Synthase Inhibitor (1400W) in Mixed-sex Cohorts of a Rat Soman (GD) Model of Epilepsy

Background Acute exposure to seizurogenic organophosphate (OP) nerve agents (OPNA) such as diisopropylfluorophosphate (DFP) or soman (GD), at high concentrations, induce immediate status epilepticus (SE), reactive gliosis, neurodegeneration, and epileptogenesis as a consequence. Medical countermeasures (MCMs- atropine, oximes, benzodiazepines), if administered in < 20 minutes of OPNA exposure, can control acute symptoms and mortality. However, MCMs alone are inadequate to prevent OPNA-induced brain injury and behavioral dysfunction in survivors. We have previously shown that OPNA exposure-induced SE increases the production of inducible nitric oxide synthase (iNOS) in glial cells in both short- and long- terms. Treating with a water soluble and highly selective iNOS inhibitor, 1400W, for three days significantly reduced OPNA-induced brain changes in those animals that had mild-moderate SE in the rat DFP model. However, such mitigating effects and the mechanisms of 1400W are unknown in a highly volatile nerve agent GD exposure. Methods Mixed-sex cohort of adult Sprague Dawley rats were exposed to GD (132µg/kg, s.c.) and immediately treated with atropine (2mg/kg, i.m) and HI-6 (125mg/kg, i.m.). Severity of seizures were quantified for an hour and treated with midazolam (3mg/kg, i.m.). An hour post-midazolam, 1400W (20mg/kg, i.m.) or vehicle was administered daily for two weeks. After behavioral testing and EEG acquisition, animals were euthanized at 3.5 months post-GD. Brains were processed for neuroinflammatory and neurodegeneration markers. Serum and CSF were used for nitrooxidative and proinflammatory cytokines assays. Results We demonstrate a significant long-term (3.5 months post-soman) disease-modifying effect of 1400W in animals that had severe SE for > 20min of continuous convulsive seizures. 1400W significantly reduced GD-induced motor and cognitive dysfunction; nitrooxidative stress (nitrite, ROS; increased GSH: GSSG); proinflammatory cytokines in the serum and some in the cerebrospinal fluid (CSF); epileptiform spikes and spontaneously recurring seizures (SRS) in males; reactive gliosis (GFAP + C3 and IBA1 + CD68 positive glia) as a measure of neuroinflammation, and neurodegeneration (including parvalbumin positive neurons) in some brain regions. Conclusion These findings demonstrate the long-term disease-modifying effects of a glial-targeted iNOS inhibitor, 1400W, in a rat GD model by modulating reactive gliosis, neurodegeneration, and neuronal hyperexcitability.

The increase of Nrf2 m6A modification induced by FTO downregulation promotes hippocampal neuron injury and aggravates the progression of epilepsy in a rat model

Epilepsy is a common chronic neurological disorder characterized by widespread neuronal death. The purpose of this study was to investigate the role of nuclear factor erythroid 2-related factor 2 (Nrf2) m6A methylation in epilepsy. To create epileptic models, the rats were given Lithium chloride and pilocarpine, and isolated primary rat hippocampal neurons were cultured in an Mg2⁺ -free medium. The frequency of seizures was recorded in the epilepsy group of rats. The functional tests included TUNEL, MTT, and flow cytometry. Mechanistically, RNA degradation assay, RNA immunoprecipitation, and methylated RNA immunoprecipitation were performed. In epileptic models, Nrf2 and fat mass and obesity-associated (FTO) levels were downregulated, whereas YT521-B homology (YTH) domain family protein 2 (YTHDF2) was upregulated. Additionally, in epileptic models, there was a rise in the m6A methylation level of Nrf2 mRNA. Overexpressing FTO increased cell viability and reduced apoptosis, but Nrf2 interference reversed these effects. Meanwhile, FTO overexpression decreased the m6A methylation of Nrf2 mRNA. Moreover, YTHDF2 bound to Nrf2 mRNA and decreased its stability. Furthermore, FTO overexpression reduced seizure frequency in rats and inhibited hippocampal neuron apoptosis via lowering the m6A methylation level of Nrf2 mRNA. Overexpressing FTO reduced m6A methylation of Nrf2 mRNA, increased cell viability, suppressed apoptosis, and slowed the progression of epileptic diseases, which is linked to YTHDF2 binding to m6A-modified Nrf2 and promoting its degradation, as well as downregulating Nrf2 expression in hippocampal neurons.

N-acetyl cysteine: A new look at its effect on PTZ-induced convulsions

INTRODUCTION/AIM

Epilepsy is widely investigated as a common neurological disease requiring pharmacologically effective agents. N-acetyl cysteine (NAC), has become a remarkable molecule with its role in both antioxidant and glutaminergic modulation. There are many points and processes waiting to be revealed regarding the role of NAC in epilepsy.

MATERIALS AND METHODS

Pentylenetetrazole (PTZ) was administered to induce seizures in a total number of 48 Sprague-Dawley rats. 35 mg/kg PTZ dose as a sub-convulsive dose was administered to 24 animals to monitor EEG changes, while 70 mg/kg PTZ dose which was a convulsive dose was administered to 24 animals to determine seizure-related behavioral changes with the Racine's scale. 30 min before the seizure-induced procedure, NAC was administered at doses of 300 and 600 mg/kg as pretreatment to investigate anti-seizure and anti-oxidative effects. The spike percentage, the stage of convulsion, and the onset time of the first myoclonic jerk were evaluated to determine the anti-seizure effect. Furthermore, its effect on oxidative stress was determined by measuring both malondialdehyde (MDA) level and superoxide dismutase (SOD) enzyme activity.

RESULTS

There was a dose-dependent reduction in the seizure stage and prolonged onset time of the first myoclonic jerk in rats with NAC pretreatment. EEG recordings resulted in a dose-dependent decrease in spike percentages. Moreover, the same dose-dependent changes were observed in oxidative stress biomarkers, both 300 mg/kg NAC and 600 mg/kg decreased MDA levels and ameliorated SOD activity.

CONCLUSION

We can report that 300 mg/kg and 600 mg/kg doses of NAC are promising with their reducing effect on convulsions and have a beneficial effect by preventing oxidative stress. In addition, NAC has been also determined that this effect is dose-dependent. Detailed and comparative studies are needed on the convulsion-reducing effect of NAC in epilepsy.

The potential of CYP46A1 as a novel therapeutic target for neurological disorders: An updated review of mechanisms

Cholesterol is a key component of the cell membrane that impacts the permeability, fluidity, and functions of membrane-bound proteins. It also participates in synaptogenesis, synaptic function, axonal growth, dendrite outgrowth, and microtubule stability. Cholesterol biosynthesis and metabolism are in balance in the brain. Its metabolism in the brain is mediated mainly by CYP46A1 or cholesterol 24-hydroxylase. It is responsible for eliminating about 80% of the cholesterol excess from the human brain. CYP46A1 converts cholesterol to 24S-hydroxycholesterol (24HC) that readily crosses the blood-brain barrier and reaches the liver for the final elimination process. Studies show that cholesterol and 24HC levels change during neurological diseases and conditions. So, it was hypothesized that inhibition or activation of CYP46A1 would be an effective therapeutic strategy. Accordingly, preclinical studies, using genetic and pharmacological interventions, assessed the role of CYP46A1 in main neurodegenerative disorders such as Parkinson's disease, Huntington's disease, Alzheimer's disease, multiple sclerosis, spinocerebellar ataxias, and amyotrophic lateral sclerosis. In addition, its role in seizures and brain injury was evaluated. The recent development of soticlestat, as a selective and potent CYP46A1 inhibitor, with significant anti-seizure effects in preclinical and clinical studies, suggests the importance of this target for future drug developments. Previous studies have shown that both activation and inhibition of CYP46A1 are of therapeutic value. This article, using recent studies, highlights the role of CYP46A1 in various brain diseases and insults.

Astrocyte-neuron circuits in epilepsy

The epilepsies are a diverse spectrum of disease states characterized by spontaneous seizures and associated comorbidities. Neuron-focused perspectives have yielded an array of widely used anti-seizure medications and are able to explain some, but not all, of the imbalance of excitation and inhibition which manifests itself as spontaneous seizures. Furthermore, the rate of pharmacoresistant epilepsy remains high despite the regular approval of novel anti-seizure medications. Gaining a more complete understanding of the processes that turn a healthy brain into an epileptic brain (epileptogenesis) as well as the processes which generate individual seizures (ictogenesis) may necessitate broadening our focus to other cell types. As will be detailed in this review, astrocytes augment neuronal activity at the level of individual neurons in the form of gliotransmission and the tripartite synapse. Under normal conditions, astrocytes are essential to the maintenance of blood-brain barrier integrity and remediation of inflammation and oxidative stress, but in epilepsy these functions are impaired. Epilepsy results in disruptions in the way astrocytes relate to each other by gap junctions which has important implications for ion and water homeostasis. In their activated state, astrocytes contribute to imbalances in neuronal excitability due to their decreased capacity to take up and metabolize glutamate and an increased capacity to metabolize adenosine. Furthermore, due to their increased adenosine metabolism, activated astrocytes may contribute to DNA hypermethylation and other epigenetic changes that underly epileptogenesis. Lastly, we will explore the potential explanatory power of these changes in astrocyte function in detail in the specific context of the comorbid occurrence of epilepsy and Alzheimer's disease and the disruption in sleep-wake regulation associated with both conditions.

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.

Disease-modifying effects of sodium selenate in a model of drug-resistant, temporal lobe epilepsy

There are no pharmacological disease-modifying treatments with an enduring effect to mitigate the seizures and comorbidities of established chronic temporal lobe epilepsy (TLE). This study aimed to evaluate for disease modifying effects of sodium selenate treatment in the chronically epileptic rat post-status epilepticus (SE) model of drug-resistant TLE. Wistar rats underwent kainic acid-induced SE or sham. Ten-weeks post-SE, animals received sodium selenate, levetiracetam, or vehicle subcutaneousinfusion continuously for 4 weeks. To evaluate the effects of the treatments, one week of continuous video-EEG was acquired before, during, and 4, 8 weeks post-treatment, followed by behavioral tests. Targeted and untargeted proteomics and metabolomics were performed on post-mortem brain tissue to identify potential pathways associated with modified disease outcomes. Telomere length was investigated as a novel surrogate marker of epilepsy disease severity in our current study. The results showed that sodium selenate treatment was associated with mitigation of measures of disease severity at 8 weeks post-treatment cessation; reducing the number of spontaneous seizures (p< 0.05), cognitive dysfunction (p< 0.05), and sensorimotor deficits (p< 0.01). Moreover, selenate treatment was associated with increased protein phosphatase 2A (PP2A) expression, reduced hyperphosphorylated tau, and reversed telomere length shortening (p< 0.05). Network medicine integration of multi-omics/pre-clinical outcomes identified protein-metabolite modules positively correlated with TLE. Our results provide evidence that treatment with sodium selenate results in a sustained disease-modifying effect in chronically epileptic rats in the post-KA SE model of TLE, including improved comorbid learning and memory deficits.

Neuropathological Insights into Unexpected Cognitive Decline in Epilepsy

OBJECTIVE

Some patients unexpectedly display an unfavorable cognitive course after epilepsy surgery subsequent to any direct cognitive sequelae of the surgical treatment. Therefore, we conducted in-depth neuropathological examinations of resective specimens from corresponding patients to provide insights as to the underlying disease processes.

METHODS

In this study, cases with significant cognitive deterioration following a previous postoperative assessment were extracted from the neuropsychological database of a longstanding epilepsy surgical program. An extensive reanalysis of available specimens was performed using current, state-of-the-art neuropathological examinations. Patients without cognitive deterioration but matched in regard to basic pathologies served as controls.

RESULTS

Among the 355 operated patients who had undergone more than one postoperative neuropsychological examination, 30 (8%) showed significant cognitive decline in the period after surgery. Of the 24 patients with available specimens, 71% displayed further neuropathological changes in addition to the typical spectrum (ie, hippocampal sclerosis, focal cortical dysplasias, vascular lesions, and low-grade tumors), indicating (1) a secondary, putatively epilepsy-independent neurodegenerative disease process; (2) limbic inflammation; or (3) the enigmatic pathology pattern of "hippocampal gliosis" without segmental neurodegeneration. In the controls, the matched individual principal epilepsy-associated pathologies were not found in combination with the secondary pathology patterns of the study group.

INTERPRETATION

Our findings indicate that patients who unexpectedly displayed unfavorable cognitive development beyond any direct surgical effects show rare and very particular pathogenetic causes or parallel, presumably independent, neurodegenerative alterations. A multicenter collection of such cases would be appreciated to discern presurgical biomarkers that help with surgical decision-making. ANN NEUROL 2023;93:536-550.

Neuroimmunology of status epilepticus

Status epilepticus (SE) is a very heterogeneous clinical condition often refractory to available treatment options. Evidence in animal models shows that neuroinflammation arises in the brain during SE due to the activation of innate immune mechanisms in brain parenchyma cells. Intervention studies in animal models support the involvement of neuroinflammation in SE onset, duration, and severity, refractoriness to treatments, and long-term neurological consequences. Clinical evidence shows that neuroinflammation occurs in patients with SE of diverse etiologies likely representing a common phenomenon, thus broadening the involvement of the immune system beyond the infective and autoimmune etiologies. There is urgent need for novel therapies for refractory SE that rely upon a better understanding of the basic mechanisms underlying this clinical condition. Preclinical and clinical evidence encourage consideration of specific anti-inflammatory treatments for controlling SE and its consequences in patients.

Nrf2 is expressed more extensively in neurons than in astrocytes following an acute epileptic seizure in rats

The modulation of the nuclear factor erythroid 2-like 2 (Nrf2) activity has been reported to be implicated in the pathology of various neurological disorders, including epilepsy. Previous studies have demonstrated that Nrf2 is activated in the post-status epilepticus rat model; however, the spatiotemporal as well as cell type-specific expression of Nrf2 following brief epileptic seizures remains unclear. Here, we evaluated how an acute epileptic seizure affected the expression of Nrf2 and its downstream genes in the rats' cortex and the hippocampus up to 1 week following the induced seizure. We found that after a pentylenetetrazol-induced seizure, Nrf2 significantly increased at 24 h at the mRNA level and 3 h at the protein level in the cortex. In the hippocampus, the Nrf2 mRNA level peaked at 3 h after the seizure, and no significant changes were observed in the protein level. Interestingly, the mRNA level of Nrf2 downstream genes peaked at 3-6 h after seizure in both the cortex and the hippocampus. A significant increase in the expression of Nrf2 was observed in the neuronal population of CA1 and CA3 regions of the hippocampus, as well as in the cortex. Moreover, we observed no change in the co-localization of Nrf2 with astrocytes neither in the cortex nor in CA1 and CA3. Our results revealed that following a brief acute epileptic seizure, the expression of Nrf2 and its downstream genes is transiently increased and peaked at early timepoints after the seizure predominantly in the hippocampus, and this expression is restricted to the neuronal population.

Cannabidiol reveals a disruptive strategy for 21st century epilepsy drug discovery

Over 30 antiseizure medicines (ASMs) have been uncovered in a diversity of preclinical seizure and epilepsy models, with several critical inflection points in the 20th century fundamentally transforming ASM discovery. This commentary aims to review the historical relevance of cannabidiol's (CBD; Epidiolex) approval for epilepsy in the context of other ASMs brought to market. Further, we highlight how CBD's approval may represent an inflection point for 21st century ASM discovery. CBD is one of the main phytocannabinoids of Cannabis sativa. Unlike its related phytocannabinoid, Δ9-tetrahydrocannabinol, CBD does not exert any euphorigenic, tolerance, or withdrawal effects at anticonvulsant doses. CBD also possess marked anti-inflammatory effects, offering the tantalizing potential of a new pharmacological approach in epilepsy. For decades, hints of the anticonvulsant profile of CBD had been suggested with a small handful of studies in rodent seizure models, yet difficulties in formulation, compounded by the social and regulatory pressures related to medical use of cannabis plant-derived agents constrained any clinical implementation. Nonetheless, CBD possesses a broad antiseizure profile in preclinical seizure and epilepsy models, but the transformative impact of CBD'-s approval came because of studies in a rodent model of the orphan disease Dravet syndrome (DS). DS is a pediatric developmental epileptic encephalopathy with high mortality, frequent spontaneous recurrent seizures, and marked resistance to conventional ASMs, such as phenytoin and carbamazepine. CBD was approved for DS by the US Food and Drug Administration in 2018 after convincing efficacy was established in randomized, placebo-controlled trials in children. Because of the clinical approval of CBD as a novel, cannabis plantderived ASM for DS, CBD has revealed a new strategy in ASM discovery to reignite 21st century therapeutic development for epilepsy. In this commentary, we review the major preclinical and clinical milestones of the late 20th century that made CBD, a compound historically subjected to regulatory restrictions, a key driver of a new discovery strategy for epilepsy in the 21st century.

Downregulation of oxidative stress-mediated glial innate immune response suppresses seizures in a fly epilepsy model

Previous work in our laboratory has shown that mutations in prickle (pk) cause myoclonic-like seizures and ataxia in Drosophila, similar to what is observed in humans carrying mutations in orthologous PRICKLE genes. Here, we show that pk mutant brains show elevated, sustained neuronal cell death that correlates with increasing seizure penetrance, as well as an upregulation of mitochondrial oxidative stress and innate immune response (IIR) genes. Moreover, flies exhibiting more robust seizures show increased levels of IIR-associated target gene expression suggesting they may be linked. Genetic knockdown in glia of either arm of the IIR (Immune Deficiency [Imd] or Toll) leads to a reduction in neuronal death, which in turn suppresses seizure activity, with oxidative stress acting upstream of IIR. These data provide direct genetic evidence that oxidative stress in combination with glial-mediated IIR leads to progression of an epilepsy disorder.

Reactive oxygen species in status epilepticus

It has long been recognized that status epilepticus can cause considerable neuronal damage, and this has become one of its defining features. The mechanisms underlying this damage are less clear. Excessive activation of NMDA receptors results in large rises in internal calcium, which eventually lead to neuronal death. Between NMDA receptor activation and neuronal death are a number of intermediary steps, key among which is the generation of free radicals and reactive oxygen and nitrogen species. Although it has long been thought that mitochondria are the primary source for reactive oxygen species, more recent evidence has pointed to a prominent role of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, an enzyme localized in cell membranes. There is burgeoning in vivo and in vitro evidence that therapies that target the production or removal of reactive oxygen species are not only effective neuroprotectants following status epilepticus, but also potently antiepileptogenic. Moreover, combining therapies targeted at inhibiting NADPH oxidase and at increasing endogenous antioxidants seems to offer the greatest benefits.

Peroxiredoxin 6 Regulates Glutathione Peroxidase 1-Medited Glutamine Synthase Preservation in the Hippocampus of Chronic Epilepsy Rats

Clasmatodendrosis (an autophagic astroglial degeneration) plays an important role in the regulation of spontaneous seizure duration but not seizure frequency or behavioral seizure severity in chronic epilepsy rats. Recently, it has been reported that N-acetylcysteine (NAC), a precursor to glutathione (GSH), attenuates clasmatodendritic degeneration and shortens spontaneous seizure duration in chronic epilepsy rats, although the underlying mechanisms of its anti-convulsive effects are not fully understood. To elucidate this, the present study was designed to investigate whether NAC affects astroglial glutamine synthase (GS) expression mediated by GSH peroxidase 1 (GPx1) and/or peroxiredoxin 6 (Prdx6) in the epileptic hippocampus. As compared to control animals, GS and GPx1 expressions were upregulated in reactive CA1 astrocytes of chronic epilepsy rats, while their expressions were significantly decreased in clasmatodendritic CA1 astrocytes and reactive astrocytes within the molecular layer of the dentate gyrus. Prdx6 expression was increased in reactive CA1 astrocytes as well as clasmatodendritic CA1 astrocytes. In the molecular layer of the dentate gyrus, Prdx6 expression levels were similar to those in control animals. NAC ameliorated clasmatodendrosis through the increment of GS and GPx1 expressions, while it abolished Prdx6 upregulation. 1-hexadecyl-3-(trifluoroethgl)-sn-glycerol-2 phosphomethanol (MJ33, a selective inhibitor of aiPLA2 activity of Prdx6) alleviated clasmatodendrosis by enhancing GPx1 and GS expressions in clasmatodendritic CA1 astrocytes without changing the Prdx6 level. NAC or MJ33 did not affect GS, GPx1 and Prdx6 expression in astrocytes within the molecular layer of the dentate gyrus. These findings indicate that upregulated aiPLA2 activity of Prdx6 may abolish GPx1-mediated GS preservation and lead to clasmatodendrosis in CA1 astrocytes, which would extend spontaneous seizure duration due to impaired glutamate-glutamine conversion regulated by GS. Therefore, the present data suggest that aiPLA2 activity of Prdx6 in astrocytes may be one of the upstream effectors of seizure duration in the epileptic hippocampus.

Oxidative stress: a common imbalance in diabetes and epilepsy

The brain requires a large amount of energy. Its function can be altered when energy demand exceeds supply or during metabolic disturbances such as diabetes mellitus. Diabetes, a chronic disease with a high incidence worldwide, is characterized by high glucose levels (hyperglycemia); however, hypoglycemic states may also occur due to insulin treatment or poor control of the disease. These alterations in glucose levels affect the brain and could cause epileptic seizures and status epilepticus. In addition, it is known that oxidative stress states emerge as diabetes progresses, contributing to the development of diseases secondary to diabetes, including retinopathy, nephropathy, cardiovascular alterations, and alterations in the central nervous system, such as epileptic seizures. Seizures are a complex of transient signs and symptoms resulting from abnormal, simultaneous, and excessive activity of a population of neurons, and they can be both a cause and a consequence of oxidative stress. This review aims to outline studies linking diabetes mellitus and seizures to oxidative stress, a condition that may be relevant to the development of severe seizures in diabetes mellitus patients.

Nrf2 is predominantly expressed in hippocampal neurons in a rat model of temporal lobe epilepsy

BACKGROUND

Drug resistance is a particular problem in patients with temporal lobe epilepsy, where seizures originate mainly from the hippocampus. Many of these epilepsies are acquired conditions following an insult to the brain such as a prolonged seizure. Such conditions are characterized by pathophysiological mechanisms including massive oxidative stress that synergistically mediate the secondary brain damage, contributing to the development of epilepsy. The transcription factor nuclear factor (erythroid-derived 2)-like 2 (Nrf2) has emerged in recent years as an attractive therapeutic approach targeting to upregulate the antioxidative defenses in the cell, to ameliorate the oxidative stress-induced damage. Thus, it is important to understand the characteristics of Nrf2 activation during epileptogenesis and epilepsy. Here, we studied the temporal, regional, and cell-type specific expression of Nrf2 in the brain, in a rat model of temporal lobe epilepsy.

RESULTS

Early after status-epilepticus, Nrf2 is mainly activated in the hippocampus and maintained during the whole period of epileptogenesis. Only transient expression of Nrf2 was observed in the cortex. Nevertheless, the expression of several Nrf2 antioxidant target genes was increased within 24 h after status-epilepticus in both the cortex and the hippocampus. We demonstrated that after status-epilepticus in rats, Nrf2 is predominantly expressed in neurons in the CA1 and CA3 regions of the hippocampus, and only astrocytes in the CA1 increase their Nrf2 expression.

CONCLUSIONS

In conclusion, our data identify previously unrecognized spatial and cell-type dependent activation of Nrf2 during epilepsy development, highlighting the need for a time-controlled, and cell-type specific activation of the Nrf2 pathway for mediating anti-oxidant response after brain insult, to modify the development of epilepsy.

Role of SIRT3 in neurological diseases and rehabilitation training

Sirtuin3 (SIRT3) is a deacetylase that plays an important role in normal physiological activities by regulating a variety of substrates. Considerable evidence has shown that the content and activity of SIRT3 are altered in neurological diseases. Furthermore, SIRT3 affects the occurrence and development of neurological diseases. In most cases, SIRT3 can inhibit clinical manifestations of neurological diseases by promoting autophagy, energy production, and stabilization of mitochondrial dynamics, and by inhibiting neuroinflammation, apoptosis, and oxidative stress (OS). However, SIRT3 may sometimes have the opposite effect. SIRT3 can promote the transfer of microglia. Microglia in some cases promote ischemic brain injury, and in some cases inhibit ischemic brain injury. Moreover, SIRT3 can promote the accumulation of ceramide, which can worsen the damage caused by cerebral ischemia-reperfusion (I/R). This review comprehensively summarizes the different roles and related mechanisms of SIRT3 in neurological diseases. Moreover, to provide more ideas for the prognosis of neurological diseases, we summarize several SIRT3-mediated rehabilitation training methods.

Inhibition of Prostaglandin E2 Receptor EP3 Attenuates Oxidative Stress and Neuronal Apoptosis Partially by Modulating p38MAPK/FOXO3/Mul1/Mfn2 Pathway after Subarachnoid Hemorrhage in Rats

Oxidative stress and neuronal apoptosis contribute to pathological processes of early brain injury (EBI) after subarachnoid hemorrhage (SAH). Previous studies demonstrated that the inhibition of prostaglandin E2 receptor EP3 suppressed oxidative stress and apoptotic effects after Alzheimer's disease and intracerebral hemorrhage. This study is aimed at investigating the antioxidative stress and antiapoptotic effect of EP3 inhibition and the underlying mechanisms in a rat mode of SAH. A total of 263 Sprague-Dawley male rats were used. SAH was induced by endovascular perforation. Selective EP3 antagonist L798106 was administered intranasally at 1 h, 25 h, and 49 h after SAH induction. EP3 knockout CRISPR and FOXO3 activation CRISPR were administered intracerebroventricularly at 48 h prior to SAH, while selective EP3 agonist sulprostone was administered at 1 h prior to SAH. SAH grade, neurological deficits, western blots, immunofluorescence staining, Fluoro-Jade C staining, TUNEL staining, 8-OHdG staining, and Nissl staining were conducted after SAH. The expression of endogenous PGES2 increased and peaked at 12 h while the expression of EP1, EP2, EP3, EP4, and Mul1 increased and peaked at 24 h in the ipsilateral brain after SAH. EP3 was expressed mainly in neurons. The inhibition of EP3 with L798106 or EP3 KO CRISPR ameliorated the neurological impairments, brain tissue oxidative stress, and neuronal apoptosis after SAH. To examine potential downstream mediators of EP3, we examined the effect of the increased expression of activated FOXO3 following the administration of FOXO3 activation CRISPR. Mechanism studies demonstrated that L798106 treatment significantly decreased the expression of EP3, p-p38, p-FOXO3, Mul1, 4-HNE, Bax, and cleaved caspase-3 but upregulated the expression of Mfn2 and Bcl-2 in SAH rats. EP3 agonist sulprostone or FOXO3 activation CRISPR abolished the neuroprotective effects of L798106 and its regulation on expression of p38MAPK/FOXO3/Mul1/Mfn2 in the ipsilateral brain after SAH. In conclusion, the inhibition of EP3 by L798106 attenuated oxidative stress and neuronal apoptosis partly through p38MAPK/FOXO3/Mul1/Mfn2 pathway post-SAH in rats. EP3 may serve as a potential therapeutic target for SAH patients.

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.

HMGB1 in nervous system diseases: A common biomarker and potential therapeutic target

High-mobility group box-1 (HMGB1) is a nuclear protein associated with early inflammatory changes upon extracellular secretion expressed in various cells, including neurons and microglia. With the progress of research, neuroinflammation is believed to be involved in the pathogenesis of neurological diseases such as Parkinson's, epilepsy, and autism. As a key promoter of neuroinflammation, HMGB1 is thought to be involved in the pathogenesis of Parkinson's disease, stroke, traumatic brain injury, epilepsy, autism, depression, multiple sclerosis, and amyotrophic lateral sclerosis. However, in the clinic, HMGB1 has not been described as a biomarker for the above-mentioned diseases. However, the current preclinical research results show that HMGB1 antagonists have positive significance in the treatment of Parkinson's disease, stroke, traumatic brain injury, epilepsy, and other diseases. This review discusses the possible mechanisms by which HMGB1 mediates Parkinson's disease, stroke, traumatic brain injury, epilepsy, autism, depression, multiple sclerosis, amyotrophic lateral sclerosis, and the potential of HMGB1 as a biomarker for these diseases. Future research needs to further explore the underlying molecular mechanisms and clinical translation.

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.

Lipopolysaccharide (LPS) increases susceptibility to epilepsy via interleukin-1 type 1 receptor signaling

Epilepsy is the most common disease of the nervous system, characterized by aberrant normal brain activity. Neuroinflammation is a prominent feature in the brain in epileptic humans and animal models of epilepsy. However, it remains elusive as to how peripheral inflammation affects epilepsy. Herein we demonstrated significantly greater seizure susceptibility and severity of epilepsy under kainic acid (KA) via intraperitoneal (i.p.) injection of lipopolysaccharide (LPS) in mouse model of epilepsy. Nissl staining was employed for assessment of the neuronal damage, immunofluorescence for staining of the microglial cells and astrocytes in the mouse brain slices, and ELISA for detection of the changes of inflammatory factors. We observed a smaller population of viable neurons in CA1 and CA3 regions, a greater population of IBA-1-positive and GFAP-positive cells, with a significant upregulation of IL-1β and IL-6 in hippocampus of epileptic mice when treated with LPS, indicating that LPS aggravates hippocampal neuron injury in epilepsy, and induces neuroinflammation in the hippocampus. In addition, we provide an evident increase in BrdU⁺/DCX⁺ and Nestin⁺ cell populations in dentate gyrus (DG) in LPS-treated group, versus saline group on epileptic mouse model, which demonstrated LPS treatment enhanced hippocampal neurogenesis. In order to investigate whether interleukin-1 type 1 (IL-1R1) signaling is involved in this process, we adopted IL-1R1 globally restored mice (IL-1R1^GR/GR) as an IL-1R1 reporter to visualize labeling of IL-1R1 mRNA and protein by means of RFP staining. Strikingly, the RFP immunofluorescence revealed increased IL-1R1 expression in LPS-treated group, versus saline group. Further, blockage of central IL-1R1 alleviated seizure susceptibility and severity of epilepsy. In summary, our findings suggested that LPS could enhance central inflammatory response and aggravate the susceptibility to epileptic seizure, which we postulated to be mediated by IL-1R1.

Maternal Epilepsy and Umbilical Cord Blood Oxidative Stress Level

INTRODUCTION

We investigated the effect of epilepsy on cord blood oxidative stress status.

MATERIAL AND METHODS

Thirty (n = 30) pregnant women with epilepsy and thirty (n = 30) healthy controls enrolled in this case control study. Albumin and IMA values and dynamic thiol/disulfide parameters were measured.

RESULTS

Decreased native thiol and total thiol levels were found in the epilepsy group when compared to the control group (p: 0.001, p: 0.002). Higher IMA (p: 0.036) and lower albumin cord levels (P < 0.001) were measured in the epilepsy group with respect to the control group. Apgar scores at 1 and 5 miutes were lower in the epilepsy group (respectively; p = 0.012, p = 0.010). A negative correlation was found between IMA and cord pH value (r = 0.288 p = 0.034).

CONCLUSION

This study showed that epilepsy may alter thiol disulfide homeostasis and IMA levels.

Protective role of ethyl pyruvate in spinal cord injury by inhibiting the high mobility group box-1/toll-like receptor4/nuclear factor-kappa B signaling pathway

Spinal cord injury (SCI) is a high incident rate of central nervous system disease that usually causes paralysis below the injured level. The occurrence of chronic inflammation with the axonal regeneration difficulties are the underlying barriers for the recovery of SCI patients. Current studies have paid attention to controlling the instigative and developmental process of neuro-inflammation. Ethyl pyruvate, as a derivative of pyruvate, has strong anti-inflammatory and neuroprotective functions. Herein, we reviewed the recent studies of ethyl pyruvate and high mobility group box-1 (HMGB1). We think HMGB1 that is one of the main nuclear protein mediators to cause an inflammatory response. This protein induces astrocytic activation, and promotes glial scar formation. Interestingly, ethyl pyruvate has potent inhibitory effects on HMGB1 protein, as it inhibits chronic inflammatory response by modulating the HMGB1/TLR4/NF-κB signaling pathway. This paper discusses the potential mechanism of ethyl pyruvate in inhibiting chronic inflammation after SCI. Ethyl pyruvate can be a prospective therapeutic agent for SCI.

The anticonvulsant effect of chronic treatment with topiramate after pilocarpine-induced status epilepticus is accompanied by a suppression of comorbid behavioral impairments and robust neuroprotection in limbic regions in rats

Epilepsy is a widespread neurological disorder frequently associated with a lot of comorbidities. The present study aimed to evaluate the effects of the antiseizure medication topiramate (TPM) on spontaneous motor seizures, the pathogenesis of comorbid mood and cognitive impairments, hippocampal neuronal loss, and oxidative stress and inflammation in a rat model of temporal lobe epilepsy (TLE). Vehicle/TPM treatment (80 mg/kg, p.o.) was administered 3 h after the pilocarpine (pilo)-induced status epilepticus (SE) and continued for up to 12 weeks in Wistar rats. The chronic TPM treatment caused side effects in naïve rats, including memory disturbance, anxiety, and depressive-like responses. However, the anticonvulsant effect of this drug, administered during epileptogenesis, was accompanied by beneficial activity against comorbid behavioral impairments. The drug treatment suppressed the SE-induced neuronal damage in limbic structures, including the dorsal (CA1 and CA2 subfield), the ventral (CA1, CA2 and CA3) hippocampus, the basolateral amygdala, and the piriform cortex, while was ineffective against the surge in the oxidative stress and inflammation. Our results suggest that neuroprotection is an essential mechanism of TPM against spontaneous generalized seizures and concomitant emotional and cognitive impairments.

Caloric restriction: Anti-inflammatory and antioxidant mechanisms against epileptic seizures

Caloric restriction (CR) possesses different cellular mechanisms. Though there are still gaps in the literature regarding its plausible beneficial effects, the suggestion that this alternative therapy can improve the inflammatory and antioxidant response to control epileptic seizures is explored throughout this study. Epilepsy is the second most prevalent neurodegenerative disease in the world. However, the appropriate mechanisms for it to be fully controlled are still unknown. Neuroinflammation and oxidative stress promote epileptic seizures' appearance and might even aggravate them. There is growing evidence that caloric restriction has extensive anti-inflammatory and antioxidant properties. For instance, nuclear factor erythroid 2-related factor 2 (Nrf2) and all-trans retinoic acid (ATRA) have been proposed to induce antioxidant processes and ulteriorly improve the disease progression. Caloric restriction can be an option for those patients with refractory epilepsy since it allows for anti-inflammatory and antioxidant properties to evolve within the brain areas involved.

Crosstalk between neuroinflammation and oxidative stress in epilepsy

The roles of both neuroinflammation and oxidative stress in the pathophysiology of epilepsy have begun to receive considerable attention in recent years. However, these concepts are predominantly studied as separate entities despite the evidence that neuroinflammatory and redox-based signaling cascades have significant crosstalk. Oxidative post-translational modifications have been demonstrated to directly influence the function of key neuroinflammatory mediators. Neuroinflammation can further be controlled on the transcriptional level as the transcriptional regulators NF-KB and nrf2 are activated by reactive oxygen species. Further, neuroinflammation can induce the increased expression and activity of NADPH oxidase, leading to a highly oxidative environment. These factors additionally influence mitochondria function and the metabolic status of neurons and glia, which are already metabolically stressed in epilepsy. Given the implication of this relationship to disease pathology, this review explores the numerous mechanisms by which neuroinflammation and oxidative stress influence one another in the context of epilepsy. We further examine the efficacy of treatments targeting oxidative stress and redox regulation in animal and human epilepsies in the literature that warrant further investigation. Treatment approaches aimed at rectifying oxidative stress and aberrant redox signaling may enable control of neuroinflammation and improve patient outcomes.