Clinical value of decreased superoxide dismutase 1 in patients with epilepsy

Serum biomarkers in patients with drug-resistant epilepsy: a proteomics-based analysis

Objective

To investigate the serum biomarkers in patients with drug-resistant epilepsy (DRE).

Methods

A total of 9 DRE patients and 9 controls were enrolled. Serum from DRE patients was prospectively collected and analyzed for potential serum biomarkers using TMT18-labeled proteomics. After fine quality control, bioinformatics analysis was conducted to find differentially expressed proteins. Pathway enrichment analysis identified some biological features shared by differential proteins. Protein-protein interaction (PPI) network analysis was further performed to discover the core proteins.

Results

A total of 117 serum differential proteins were found in our study, of which 44 were revised upwards and 73 downwards. The up-regulated proteins mainly include UGGT2, PDIA4, SEMG1, KIAA1191, CCT7 etc. and the down-regulated proteins mainly include ROR1, NIF3L1, ITIH4, CFP, COL11A2 etc. Pathway enrichment analysis identified that the upregulated proteins were mainly enriched in processes such as immune response, extracellular exosome, serine-type endopeptidase activity and complement and coagulation cascades, and the down-regulated proteins were enriched in signal transduction, extracellular exosome, zinc/calcium ion binding and metabolic pathways. PPI network analysis revealed that the core proteins nodes include PRDX6, CAT, PRDX2, SOD1, PARK7, GSR, TXN, ANXA1, HINT1, and S100A8 etc.

Conclusion

The discovery of these differential proteins enriched our understanding of serum biomarkers in patients with DRE and potentially provides guidance for future targeted therapy.

The inhibition of PGAM5 suppresses seizures in a kainate-induced epilepsy model via mitophagy reduction

Background

Epilepsy is a common neurological disease, and excessive mitophagy is considered as one of the major triggers of epilepsy. Mitophagy is a crucial pathway affecting reactive oxygen species. Phosphoglycerate mutase 5 (PGAM5) is a protein phosphatase present in mitochondria that regulates many biological processes including mitophagy and cell death. However, the mechanism of PGAM5 in epilepsy remains unclear. The purpose of the present study was to examine whether PGAM5 affects epilepsy through PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy.

Methods

After the knockdown of PGAM5 expression by the adeno-associated virus, an epilepsy model was created by kainic acid. Next, the seizure activity was recorded by local field potentials before evaluating the level of mitochondrial autophagy marker proteins. Lastly, the ultrastructure of mitochondria, neuronal damage and oxidative stress levels were further observed.

Results

A higher PGAM5 level was found in epilepsy, and its cellular localization was in neurons. The interactions between PGAM5 and PINK1 in epilepsy were further found. After the knockdown of PGAM5, the level of PINK1 and light chain 3B was decreased and the expression of the translocase of the inner mitochondrial membrane 23 and translocase of the outer mitochondrial membrane 20 were both increased. Knockdown of PGAM5 also resulted in reduced neuronal damage, decreased malondialdehyde levels, decreased reactive oxygen species production and increased superoxide dismutase activity. In addition, the duration of spontaneous seizure-like events (SLEs), the number of SLEs and the time spent in SLEs were all reduced in the epilepsy model after inhibition of PGAM5 expression.

Conclusion

Inhibition of PGAM5 expression reduces seizures via inhibiting PINK1-mediated mitophagy.

Graphene Nanoplatelets: In Vivo and In Vitro Toxicity, Cell Proliferative Activity, and Cell Gene Expression

Multi-layer graphene (2–10 layers), also called graphene nanoplatelets (GNPs), is a carbon-based nanomaterial (CBN) type with excellent properties desirable for many biomedical applications. Despite the promising advantages reported of GNPs, nanoscale materials may also present a potential hazard to humans. Therefore, in this study, the in vivo toxicity of these nanomaterials at a wide range of concentrations from 12.5 to 500 µg/mL was evaluated in the Caenorhabditis elegans model for 24 h (acute toxicity) and 72 h (chronic toxicity). Furthermore, their in vitro toxicity (from 0 to 10 µg/mL for 12 and 24 h), proliferative activity at 72 and 96 h, and their effect on the expression of thirteen genes in human keratinocytes HaCaT cells were studied. The physico-chemical and morphological aspects of the GNPs used in this study were analyzed by Raman scattering spectroscopy, electron microscopy, zeta potential as a function of pH, and particle size measurements by dynamic light scattering. The results of this study showed that GNPs showed in vivo non-toxic concentrations of 25 and 12.5 µg/mL for 24 h, and at 12.5 µg/mL for 72 h. Moreover, GNPs present time-dependent cytotoxicity (EC50 of 1.142 µg/mL and 0.760 µg/mL at 12 h and 24 h, respectively) and significant proliferative activity at the non-toxic concentrations of 0.005 and 0.01 μg/mL in the HaCaT cell line. The gene expression study showed that this multi-layer-graphene is capable of up-regulating six of the thirteen genes of human keratinocytes (SOD1, CAT, TGFB1, FN1, CDH1, and FBN), two more genes than other CBNs in their oxidized form such as multi-layer graphene oxide. Therefore, all these results reinforce the promising use of these CBNs in biomedical fields such as wound healing and skin tissue engineering.

Carbon Nanofibers versus Silver Nanoparticles: Time-Dependent Cytotoxicity, Proliferation, and Gene Expression

Carbon nanofibers (CNFs) are one-dimensional nanomaterials with excellent physical and broad-spectrum antimicrobial properties characterized by a low risk of antimicrobial resistance. Silver nanoparticles (AgNPs) are antimicrobial metallic nanomaterials already used in a broad range of industrial applications. In the present study these two nanomaterials were characterized by Raman spectroscopy, transmission electron microscopy, zeta potential, and dynamic light scattering, and their biological properties were compared in terms of cytotoxicity, proliferation, and gene expression in human keratinocyte HaCaT cells. The results showed that both AgNPs and CNFs present similar time-dependent cytotoxicity (EC50 of 608.1 µg/mL for CNFs and 581.9 µg/mL for AgNPs at 24 h) and similar proliferative HaCaT cell activity. However, both nanomaterials showed very different results in the expression of thirteen genes (superoxide dismutase 1 (SOD1), catalase (CAT), matrix metallopeptidase 1 (MMP1), transforming growth factor beta 1 (TGFB1), glutathione peroxidase 1 (GPX1), fibronectin 1 (FN1), hyaluronan synthase 2 (HAS2), laminin subunit beta 1 (LAMB1), lumican (LUM), cadherin 1 CDH1, collagen type IV alpha (COL4A1), fibrillin (FBN), and versican (VCAN)) treated with the lowest non-cytotoxic concentrations in the HaCaT cells after 24 h. The AgNPs were capable of up-regulating only two genes (SOD1 and MMP1) while the CNFs were very effective in up-regulating eight genes (FN1, MMP1, CAT, CDH1, COL4A1, FBN, GPX1, and TGFB1) involved in the defense mechanisms against oxidative stress and maintaining and repairing tissues by regulating cell adhesion, migration, proliferation, differentiation, growth, morphogenesis, and tissue development. These results demonstrate CNF nanomaterials' unique great potential in biomedical applications such as tissue engineering and wound healing.

Diagnostic utility of cerebrospinal fluid (CSF) findings in seizures and epilepsy with and without autoimmune-associated disease

Patients with seizures and epilepsy routinely undergo multiple diagnostic tests, which may include cerebrospinal fluid (CSF) analysis. This review aims to outline different CSF parameters and their alterations in seizures or epilepsy. We then discuss the utility of CSF analysis in seizure patients in different clinical settings in depth. Some routine CSF parameters are frequently altered after seizures, but are not specific such as CSF protein and lactate. Pleocytosis and CSF specific oligoclonal bands are rare and should be considered as signs of infectious or immune mediated seizures and epilepsy. Markers of neuronal damage show conflicting results, and are as yet not established in clinical practice. Parameters of neuronal degeneration and more specific immune parameters are less well studied, and are areas of further research. CSF analysis in new-onset seizures or status epilepticus serves well in the differential diagnosis of seizure etiology. Here, considerations should include autoimmune-associated seizures. CSF findings in these disorders are a special focus of this review and are summarized in a comprehensive overview. Until now, CSF analysis has not yielded clinically helpful biomarkers for refractory epilepsy or for assessment of neuronal damage which is a subject of further studies.

Mechanisms of microRNA‑142 in mitochondrial autophagy and hippocampal damage in a rat model of epilepsy

Researchers have confirmed the microRNA (miRNA/miR)‑epilepsy association in rodent models of human epilepsy via a comprehensive database. However, the mechanisms of miR‑142 in epilepsy have not been extensively studied. In the present study, a rat model of epilepsy was first established by an injection of lithium chloride‑pilocarpine and the successful establishment of the model was verified via electroencephalogram monitoring. The levels of miR‑142, phosphatase and tensin homolog deleted on chromosome 10 (PTEN)‑induced putative kinase 1 (PINK1), marker proteins of mitochondrial autophagy, and apoptosis‑related proteins were measured. Additionally, the pathological changes in the hippocampus, the ultrastructure of the mitochondria, and degeneration and the apoptosis of neurons were observed using different staining methods. The malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in the hippocampus, mitochondrial membrane potential (MTP) and reactive oxygen species (ROS) generation were detected. Furthermore, the targeting association between miR‑142 and PINK1 was predicted and verified. Consequently, apoptosis increased, and mitochondrial autophagy decreased, in the hippocampus of epileptic rats. Following miR‑142 inhibition, the epileptic rats exhibited an increased Bax expression, a decreased Bcl‑2 expression, upregulated marker protein levels of mitochondrial autophagy, a reduced MDA content, an enhanced SOD activity, an increased MTP and decreased ROS generation. PINK1 is a target gene of miR‑142, and its overexpression protected against hippocampal damage. Taken together, the results of the present study demonstrated that miR‑142 inhibition promotes mitochondrial autophagy and reduces hippocampal damage in epileptic rats by targeting PINK1. These findings may provide useful information for the treatment of epilepsy.

Stem cells: A path towards improved epilepsy therapies

Despite the immense growth of new anti-seizure drugs (ASDs), approximately one-third of epilepsy patients remain resistant to current treatment options. Advancements in whole genome sequencing technology continues to identify an increasing number of epilepsy-associated genes at a rate that is outpacing the development of in vivo animal models. Patient-derived induced pluripotent stem cells (iPSCs) show promise in providing a platform for modeling genetic epilepsies, high throughput drug screening, and personalized medicine. This is largely due to the ease of collecting donor cells for iPSC reprogramming, and their ability to be maintained in vitro, while preserving the patient's genetic background. In this review, we summarize the current state of iPSC research in epilepsy and closely related syndromes, discuss the growing need for high-throughput drug screening (HTS), and review the use of stem cell technology for the purpose of autologous transplantation for epilepsy stem cell therapy. Although the use of iPSC technology, as it applies to ASD discovery, is in its infancy, we highlight the significant progress that has been made in phenotype and assay development to facilitate systematic HTS for personalized medicine. This article is part of the special issue entitled 'New Epilepsy Therapies for the 21st Century - From Antiseizure Drugs to Prevention, Modification and Cure of Epilepsy'.

Anticonvulsant and Antioxidant Effects of Pitavastatin Against Pentylenetetrazol-Induced Kindling in Mice

Purpose: The pleiotropic effects of statins (antioxidant and anti-inflammation) have been reported by previous studies. Therefore, we aimed to determine whether pitavastatin has protective effects against pentylenetetrazol (PTZ)-induced kindling in mice and also whether pitavastatin improves the brain antioxidant capacity and attenuates the oxidative injuries in kindled mice.

Methods: Twenty-four mice were randomly divided into four groups (each group n=6); control, PTZ-kindling and PTZ-kindled rats treated with pitavastatin (1&4 mg/kg). PTZ kindling seizures were induced by repetitive intraperitoneal injections of PTZ (65 mg/kg) every 48 hours till day twenty-one. Animals received daily oral pitavastatin for twenty-one days. Latency, score and duration of the seizures were recorded. The activities of catalase (CAT) ad superoxide dismutase (SOD), and likewise the contents of malondialdehyde (MDA) and nitrate were assessed in the brains of all rats.

Results: There was a progressive reduction in latency of the kindled rats in the next injections of PTZ. Pitavastatin reduced this value (latency) particularly at higher dose. Seizures duration and score also decreased in treatment groups. SOD and CAT activities significantly decreased in PTZ-kindling group by 62% and 64%, respectively, but pitavastatin did not significantly change the SOD and CAT activities. Brain MDA and nitrate significantly increased in PTZ-kindling group by 53% and 30%, respectively. Pitavastatin at higher dose significantly decreased the MDA and nitrate contents of PTZ-kindling rats by 45% and 32%, respectively.

Conclusion: Our findings revealed that pitavastatin can improve the behavioral expression of the PTZ-kindling rats and attenuate the seizure-induced oxidative/nitrosative damage.

Peripheral inflammation increases seizure susceptibility via the induction of neuroinflammation and oxidative stress in the hippocampus

BACKGROUND

Neuroinflammation with activation of microglia and production of proinflammatory cytokines in the brain plays an active role in epileptic disorders. Brain oxidative stress has also been implicated in the pathogenesis of epilepsy. Damage in the hippocampus is associated with temporal lobe epilepsy, a common form of epilepsy in human. Peripheral inflammation may exacerbate neuroinflammation and brain oxidative stress. This study examined the impact of peripheral inflammation on seizure susceptibility and the involvement of neuroinflammation and oxidative stress in the hippocampus.

RESULTS

In male, adult Sprague-Dawley rats, peripheral inflammation was induced by the infusion of Escherichia coli lipopolysaccharide (LPS, 2.5 mg/kg/day) into the peritoneal cavity for 7 days via an osmotic minipump. Pharmacological agents were delivered via intracerebroventricular (i.c.v.) infusion with an osmotic minipump. The level of cytokine in plasma or hippocampus was analyzed by ELISA. Redox-related protein expression in hippocampus was evaluated by Western blot. Seizure susceptibility was tested by intraperitoneal (i.p.) injection of kainic acid (KA, 10 mg/kg). We found that i.p. infusion of LPS for 7 days induced peripheral inflammation characterized by the increases in plasma levels of interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α). This is associated with a significant increase in number of the activated microglia (Iba-1(+) cells), enhanced production of proinflammatory cytokines (including IL-1β, IL-6 and TNF-α), and tissue oxidative stress (upregulations of the NADPH oxidase subunits) in the hippocampus. These cellular and molecular responses to peripheral inflammation were notably blunted by i.c.v. infusion of a cycloxygenase-2 inhibitor, NS398 (5 μg/μl/h). The i.c.v. infusion of tempol (2.5 μg/μl/h), a reactive oxygen species scavenger, protected the hippocampus from oxidative damage with no apparent effect on microglia activation or cytokine production after peripheral inflammation. In the KA-induced seizure model, i.c.v. infusion of both NS398 and tempol ameliorated the increase in seizure susceptibility in animals succumbed to the LPS-induced peripheral inflammation.

CONCLUSIONS

Together these results indicated that LPS-induced peripheral inflammation evoked neuroinflammation and the subsequent oxidative stress in the hippocampus, resulting in the increase in KA-induced seizure susceptibility. Moreover, protection from neuroinflammation and oxidative stress in the hippocampus exerted beneficial effect on seizure susceptibility following peripheral inflammation.

Seizure-induced oxidative stress in temporal lobe epilepsy

An insult to the brain (such as the first seizure) causes excitotoxicity, neuroinflammation, and production of reactive oxygen/nitrogen species (ROS/RNS). ROS and RNS produced during status epilepticus (SE) overwhelm the mitochondrial natural antioxidant defense mechanism. This leads to mitochondrial dysfunction and damage to the mitochondrial DNA. This in turn affects synthesis of various enzyme complexes that are involved in electron transport chain. Resultant effects that occur during epileptogenesis include lipid peroxidation, reactive gliosis, hippocampal neurodegeneration, reorganization of neural networks, and hypersynchronicity. These factors predispose the brain to spontaneous recurrent seizures (SRS), which ultimately establish into temporal lobe epilepsy (TLE). This review discusses some of these issues. Though antiepileptic drugs (AEDs) are beneficial to control/suppress seizures, their long term usage has been shown to increase ROS/RNS in animal models and human patients. In established TLE, ROS/RNS are shown to be harmful as they can increase the susceptibility to SRS. Further, in this paper, we review briefly the data from animal models and human TLE patients on the adverse effects of antiepileptic medications and the plausible ameliorating effects of antioxidants as an adjunct therapy.

The search for circulating epilepsy biomarkers

Few would experience greater benefit from the development of biomarkers than those who suffer from epilepsy. Both the timing of individual seizures and the overall course of the disease are highly unpredictable, and the associated morbidity is considerable. Thus, there is an urgent need to develop biomarkers that can predict the progression of epilepsy and treatment response. Doing so may also shed light on the mechanisms of epileptogenesis and pharmacoresistance, which remain elusive despite decades of study. However, recent advances suggest the possible identification of circulating epilepsy biomarkers – accessible in blood, cerebrospinal fluid or urine. In this review, we focus on advances in several areas: neuroimmunology and inflammation; neurological viral infection; exemplary pediatric syndromes; and the genetics of pharmacoresistance, as relevant to epilepsy. These are fertile areas of study with great potential to yield accessible epilepsy biomarkers.

Changes in gene expression in the frontal cortex of rats with pilocarpine-induced status epilepticus after sleep deprivation

Sleep and epilepsy present a bidirectional interaction. Sleep complaints are common in epilepsy, and sleep deprivation may provoke seizures. However, the mechanisms underlying this relationship are unknown. Thus, this study investigated the effects of paradoxical sleep deprivation (PSD24h) and total sleep deprivation (TSD6h) in the expression of genes related to reactive oxygen species and nitric oxide production in the frontal cortex of a rodent model of temporal lobe epilepsy (PILO). The data show that PILO rats had increased NOX-2 expression and decreased SOD expression, independent of sleep. Higher NOX-2 expression was observed only in PILO rats subjected to the control condition and TSD6h. Also, eNOS and DDAH1 were increased in the PILO group submitted to TSD6h. Moreover, CAT expression in the frontal cortex of PILO rats submitted to PSD24h was reduced compared to that of PILO rats that were not sleep-deprived. The molecular changes found in the frontal cortex of PILO rats following sleep deprivation suggest a mechanism via oxidative stress.