Inflammatory and neurotrophic factor plasma levels are related to epilepsy independently of etiology

Interleukin-6 in epilepsy and its neuropsychiatric comorbidities: How to bridge the gap

There is growing evidence that interleukin (IL)-6 plays an important role in neurological and psychiatric disorders. This editorial comments on the study published in the recent issue of the World Journal of Psychiatry, which employed Mendelian randomization to identify a causal relationship between IL-6 receptor blockade and decreased epilepsy incidence. The purpose of this editorial is to highlight the dual effects of IL-6 in epilepsy and its related neuropsychiatric comorbidities. IL-6 plays a critical role in the facilitation of epileptogenesis and maintenance of epileptic seizures and is implicated in neuroinflammatory processes associated with epilepsy. Furthermore, IL-6 significantly influences mood regulation and cognitive dysfunction in patients with epilepsy, highlighting its involvement in neuropsychiatric comorbidities. In summary, IL-6 is not only a pivotal factor in the pathogenesis of epilepsy but also significantly contributes to the emergence of epilepsy-related neuropsychiatric complications. Future research should prioritize elucidating the specific mechanisms by which IL-6 operates across different subtypes, stages and neuropsychiatric comorbidities of epilepsy, with the aim of developing more precise and effective interventions. Furthermore, the potential of IL-6 as a biomarker for the early diagnosis and prognosis of epilepsy warrants further investigation.

Concentration of IL-1β, IL-7, IL-12, IL-17, CX3CL1, ITAC and relation with the seizure severity and sudden unexpected death in epilepsy patient

OBJECTIVE

Inflammation plays an important role in epilepsy. There is evidence for the relationship between proinflammatory cytokines and epilepsy. We aimed to detect the serum levels of multiple cytokines in epilepsy patients, looking for biological indicators, and providing a theoretical basis for the clinical diagnosis, treatment, and prognosis of epilepsy.

MATERIALS AND METHODS

In this study, 30 patients with drug-resistant epilepsy (DRE), 30 patients with well-controlled epilepsy (WCE), and 29 healthy controls (HC) were enrolled. Multi-proinflammatory cytokines were measured by LUMINX multi-factor detection.

RESULTS

The levels of IL-1β, IL-7, IL-12, and IL-17 were significantly elevated, and the levels of CX3CL1 and ITAC were significantly decreased in epilepsy patients compared with healthy controls. Furthermore, the level of IL-17 was significantly higher in the DRE group compared to WCE. We also found the ratio of IL-7/CX3CL discriminates accurately between patients and controls, with a ROC Area Under the Curve (AUC) of 0.963 (P<0.001). The levels of IL-1β, IL-7, IL-12, and IL-17 in the DRE group were positively correlated with the National Hospital Seizure Severity Scale (NHS3) scores (IL-1β, P = 0.029; IL-12, P = 0.039; IL-17, P = 0.004). IL-17 was positively correlated with seizure frequency (P = 0.050), while ITAC was negatively correlated with seizure frequency (P = 0.012) and Sudden Unexpected Death in Epilepsy-3 (SUDEP-3) scores (P = 0.023).

CONCLUSIONS

IL-1β, IL-12, and IL-17 may be used to predict seizure severity and the IL-7/CX3CL1 ratio may be a candidate biomarker for predicting epileptic seizures. While CX3CL1 and ITAC play anti-epileptic effects, ITAC may be used to assess the risk of SUDEP.

Neuroprotective Effects of Myricetin on PTZ-Induced Seizures in Mice: Evaluation of Oxidation, Neuroinflammation and Metabolism, and Apoptosis in the Hippocampus

Epilepsy is one of the most frequently diagnosed neurological diseases, but the neurobiological basis of the disease remains poorly understood. Immunophenotyping CBA mice brain (NeuN and caspase-8) in parallel with hippocampal neurons' functional status and survival rate assessment during acute epileptic PTZ-induced seizures is of particular interest. The aims of this study were to investigate the involvement of NeuN and caspase-8 in cell cycle regulation and the death of hippocampal neurons during PTZ-induced seizures in mice and to assess the therapeutic efficacy of Myricetin in the aforementioned experimental settings. Male CBA mice (n = 340) were divided into six groups to investigate the neuroprotective and antiepileptic effects of Myricetin and Valproic Acid in the PTZ-induced seizure model. Group I (control, n = 20) received a single intraperitoneal injection of NaCl 0.9% solution. Group II (PTZ only, n = 110) received a single intraperitoneal 45 mg/kg PTZ to induce seizures. Group III (Myricetin + PTZ, n = 90) was administered Myricetin orally at 200 mg/kg for 5 days, followed by a PTZ injection. Group IV (Valproic Acid + PTZ, n = 80) received intraperitoneal Valproic Acid at 100 mg/kg for 5 days, followed by PTZ. Group V (Myricetin + NaCl, n = 20) received Myricetin and NaCl. Group VI (Valproic Acid + NaCl, n = 20) received Valproic Acid and NaCl. Seizure severity was monitored using the modified Racine scale. Behavioral assessments included sensorimotor function tests, motor coordination using the rotarod test, and cognitive function via the Morris water maze. Brain tissues were collected and analyzed for oxidative stress markers, including malondialdehyde (MDA), superoxide dismutase (SOD), and glutathione (GSH). Blood samples were analyzed for cytokine levels (IL-1β, IL-6, and TNF-α). Histological studies involved H&E and Nissl staining to evaluate general histopathology and neuronal density. Immunohistochemical analysis was conducted using antibodies against NeuN and caspase-8 to assess neuronal cell cycle regulation and apoptosis. PTZ-induced seizures caused significant oxidative stress and inflammation, leading to neuronal damage. Biochemical analyses showed elevated levels of MDA, SOD, GSH, IL-1β, IL-6, and TNF-α. Histological and immunohistochemical evaluations revealed a significant increase in caspase-8-positive neurons and a decrease in NeuN-positive neurons in the hippocampus and other brain regions, correlating with seizure severity. Myricetin and Valproic Acid treatments reduced oxidative stress markers and neuronal damage. Both treatments resulted in moderate neuronal protection, with fewer damaged neurons observed in the hippocampus, dentate gyrus, and other brain areas compared to the PTZ-only group. Summarizing, Myricetin administration showed promising neuroprotective effects. It significantly reduced oxidative stress markers, including MDA, and restored antioxidant enzyme activities (SOD and GSH), suggesting its antioxidative potential. Myricetin also effectively attenuated the elevation of pro-inflammatory cytokines IL-1β, IL-6, and TNF-α, indicating strong anti-inflammatory properties. Behavioral assessments revealed that Myricetin improved cognitive and motor functions in PTZ-treated mice, with notable reductions in seizure severity and mortality rates. Histological analyses supported these behavioral findings, with Nissl staining showing reduced neuronal damage and NeuN staining indicating better preservation of neuronal integrity in Myricetin-treated groups. Additionally, caspase-8 staining suggested a significant reduction in neuronal apoptosis.

The incidence and predictive factors of secondary epilepsy in patients with supratentorial brain metastases (st-BMs) after stereotactic radiosurgery: A multicenter retrospective study

OBJECTIVE

To evaluate the incidence and the independent risk factors of SRS-related epilepsy in patients with supratentorial brain metastases (st-BMs), providing evidences for prevention or reduction secondary epilepsy after SRS.

METHODS

Patients with st-BMs from four gamma knife centers who developed secondary epilepsy after SRS were retrospectively studied between January 1, 2017 and June 31, 2023. The incidence and clinical characteristics of the patients with secondary epilepsy were analyzed. The predictive role of baseline clinical-demographic variables was evaluated according to univariate and multivariate logistic regression model. The impact of secondary epilepsy on patients' OS was evaluated as well by log-rank test.

RESULTS

11.3 % (126/1120) of the patients with totally 158 st-BMs experienced secondary epilepsy after SRS in median 21 days. 61.9 % (78/126) of the patients experienced simple partial seizures. 91.3 % (115/126) patients achieved good seizure control after received 1-2 kinds of AEDs for median 90 days, while 7.1 % (9/126) of the patients suffered from refractory epilepsy. Patients had higher risk of secondary epilepsy if the tumor located in cortex and/or hippocampus, peri-tumor edema larger than 20.3 cm3 before SRS, had epilepsy history, and failed to receive bevacizumab prior to SRS. There was no difference in the OS of patients who experience secondary epilepsy or not after SRS.

CONCLUSIONS

The incidence of SRS-related secondary epilepsy is 11.3 % in patients with st-BMs in this retrospective study. The risk of secondary epilepsy is higher in patients with st-BM located in cortex and/or hippocampus area, peri-tumor edema larger than 20.3 cm3 before SRS, and epilepsy history. Bevacizumab is suggested prior to SRS therapy, as it could be used for the control of peri-tumor edema and SRS-related damage, hence reduce the risk of secondary epilepsy. However, whether or not patients suffered from secondary epilepsy after SRS does not affect their OS.

Comparative Proteomic Profiling of Blood Plasma Revealed Marker Proteins Involved in Temporal Lobe Epilepsy

Temporal lobe epilepsy has various origins, involving or not involving structural changes in brain tissue. The mechanisms of epileptogenesis are associated with cell regulation and signaling disruptions expressed in varied levels of proteins. The blood plasma proteomic profiling of temporal lobe epilepsy patients (including magnetic resonance imaging (MRI)-positive and MRI-negative ones) and healthy volunteers using mass spectrometry and label-free quantification revealed a list of differently expressed proteins. Several apolipoproteins (APOA1, APOD, and APOA4), serpin protease inhibitors (SERPINA3, SERPINF1, etc.), complement components (C9, C8, and C1R), and a total of 42 proteins were found to be significantly upregulated in the temporal lobe epilepsy group. A classification analysis of these proteins according to their biological functions, as well as a review of the published sources, disclosed the predominant involvement of the processes mostly affected during epilepsy such as neuroinflammation, intracellular signaling, lipid metabolism, and oxidative stress. The presence of several proteins related to the corresponding compensatory mechanisms has been noted. After further validation, the newly identified temporal lobe epilepsy biomarker candidates may be used as epilepsy diagnostic tools, in addition to other less specific methods such as electroencephalography or MRI.

A Systematic Review of the Predictive and Diagnostic Uses of Neuroinflammation Biomarkers for Epileptogenesis

A central role for neuroinflammation in epileptogenesis has recently been suggested by several investigations. This systematic review explores the role of inflammatory mediators in epileptogenesis, its association with seizure severity, and its correlation with drug-resistant epilepsy (DRE). The study analysed articles published in JCR journals from 2019 to 2024. The search strategy comprised the MESH, free terms of "Neuroinflammation", and selective searches for the following single biomarkers that had previously been selected from the relevant literature: "High mobility group box 1/HMGB1", "Toll-Like-Receptor 4/TLR-4", "Interleukin-1/IL-1", "Interleukin-6/IL-6", "Transforming growth factor beta/TGF-β", and "Tumour necrosis factor-alpha/TNF-α". These queries were all combined with the MESH terms "Epileptogenesis" and "Epilepsy". We found 243 articles related to epileptogenesis and neuroinflammation, with 356 articles from selective searches by biomarker type. After eliminating duplicates, 324 articles were evaluated, with 272 excluded and 55 evaluated by the authors. A total of 21 articles were included in the qualitative evaluation, including 18 case-control studies, 2 case series, and 1 prospective study. As conclusion, this systematic review provides acceptable support for five biomarkers, including TNF-α and some of its soluble receptors (sTNFr2), HMGB1, TLR-4, CCL2 and IL-33. Certain receptors, cytokines, and chemokines are examples of neuroinflammation-related biomarkers that may be crucial for the early diagnosis of refractory epilepsy or may be connected to the control of epileptic seizures. Their value will be better defined by future studies.

Causal links between gut microbiomes, cytokines and risk of different subtypes of epilepsy: a Mendelian randomization study

Objective

Recent research suggests a potential link between the gut microbiome (GM) and epilepsy. We undertook a Mendelian randomization (MR) study to determine the possible causal influence of GM on epilepsy and its various subtypes, and explore whether cytokines act as mediators.

Methods

We utilized Genome-Wide Association Study (GWAS) summary statistics to examine the causal relationships between GM, cytokines, and four epilepsy subtypes. Furthermore, we assessed whether cytokines mediate the relationship between GM and epilepsy. Significant GMs were further investigated using transcriptomic MR analysis with genes mapped from the FUMA GWAS. Sensitivity analyses and reverse MR were conducted for validation, and false discovery rate (FDR) correction was applied for multiple comparisons.

Results

We pinpointed causal relationships between 30 GMs and various epilepsy subtypes. Notably, the Family Veillonellaceae (OR:1.03, 95%CI:1.02-1.05, p = 0.0003) consistently showed a strong positive association with child absence epilepsy, and this causal association endured even after FDR correction (p-FDR < 0.05). Seven cytokines were significantly associated with epilepsy and its subtypes. A mediating role for cytokines has not been demonstrated. Sensitivity tests validated the primary MR analysis outcomes. Additionally, no reverse causality was detected between significant GMs and epilepsy. Of the mapped genes of notable GMs, genes like BLK, FDFT1, DOK2, FAM167A, ZSCAN9, RNGTT, RBM47, DNAJC21, SUMF1, TCF20, GLO1, TMTC1, VAV2, and RNF14 exhibited a profound correlation with the risk factors of epilepsy subtypes.

Conclusion

Our research validates the causal role of GMs and cytokines in various epilepsy subtypes, and there has been no evidence that cytokines play a mediating role between GM and epilepsy. This could provide fresh perspectives for the prevention and treatment of epilepsy.

Interleukins in Epilepsy: Friend or Foe

Epilepsy is a chronic neurological disorder with recurrent unprovoked seizures, affecting ~ 65 million worldwide. Evidence in patients with epilepsy and animal models suggests a contribution of neuroinflammation to epileptogenesis and the development of epilepsy. Interleukins (ILs), as one of the major contributors to neuroinflammation, are intensively studied for their association and modulatory effects on ictogenesis and epileptogenesis. ILs are commonly divided into pro- and anti-inflammatory cytokines and therefore are expected to be pathogenic or neuroprotective in epilepsy. However, both protective and destructive effects have been reported for many ILs. This may be due to the complex nature of ILs, and also possibly due to the different disease courses that those ILs are involved in. In this review, we summarize the contributions of different ILs in those processes and provide a current overview of recent research advances, as well as preclinical and clinical studies targeting ILs in the treatment of epilepsy.

The Possible Role of Brain-derived Neurotrophic Factor in Epilepsy

Epilepsy is a neurological disease characterized by repeated seizures. Despite of that the brain-derived neurotrophic factor (BDNF) is implicated in the pathogenesis of epileptogenesis and epilepsy, BDNF may have a neuroprotective effect against epilepsy. Thus, the goal of the present review was to highlight the protective and detrimental roles of BDNF in epilepsy. In this review, we also try to find the relation of BDNF with other signaling pathways and cellular processes including autophagy, mTOR pathway, progranulin (PGN), and α-Synuclein (α-Syn) which negatively and positively regulate BDNF/tyrosine kinase receptor B (TrkB) signaling pathway. Therefore, the assessment of BDNF levels in epilepsy should be related to other neuronal signaling pathways and types of epilepsy in both preclinical and clinical studies. In conclusion, there is a strong controversy concerning the potential role of BDNF in epilepsy. Therefore, preclinical, molecular, and clinical studies are warranted in this regard.

Differential inflammation responses determine the variable phenotypes of epilepsy induced by GABRG2 mutations

OBJECTIVE

To explore the mechanism involved in variable phenotypes of epilepsy models induced by γ-aminobutyric acid type A γ2 subunit (GABRG2) mutations.

METHODS

The zebrafish carrying wild-type (WT) GABRG2, mutant GABRG2(P282S), GABRG2(F343L) and GABRG2(I107T) were established by Tol2kit transgenesis system and Gateway method. Behavioral analysis of different transgenic zebrafish was performed with the DanioVision Video-Track framework and the brain activity was analyzed by field potential recording with MD3000 Bio-signal Acquisition and Processing System. The transcriptome analysis was applied to detect the underlying mechanisms of variable phenotypes caused by different GABRG2 mutations.

RESULTS

The established Tg(hGABRG2P282S ) zebrafish showed hyperactivity and spontaneous seizures, which were more sensitive to chemical and physical epileptic stimulations. Traditional antiepileptic drugs, such as Clonazepam (CBZ) and valproic acid (VPA), could ameliorate the hyperactivity in Tg(hGABRG2P282S ) zebrafish. The metabolic pathway was significantly changed in the brain transcriptome of Tg(hGABRG2P282S ) zebrafish. In addition, the behavioral activity, production of pro-inflammatory factors, and activation of the IL-2 receptor signal pathway varied among the three mutant zebrafish lines.

CONCLUSION

We successfully established transgenic zebrafish epileptic models expressing human mutant GABRG2(P282S), in which CBZ and VPA showed antiepileptic effects. Differential inflammatory responses, especially the SOCS/JAK/STAT signaling pathway, might be related to the phenotypes of genetic epilepsy induced by GABRG2 mutations. Further study will expand the pathological mechanisms of genetic epilepsies and provide a theoretical basis for searching for effective drug treatment.

Reduced Levels of Lacrimal Glial Cell Line-Derived Neurotrophic Factor (GDNF) in Patients with Focal Epilepsy and Focal Epilepsy with Comorbid Depression: A Biomarker Candidate

Our previous studies showed that in patients with brain diseases, neurotrophic factors in lacrimal fluid (LF) may change more prominently than in blood serum (BS). Since glial cell line-derived neurotrophic factor (GDNF) is involved in the control of neuronal networks in an epileptic brain, we aimed to assess the GDNF levels in LF and BS as well as the BDNF and the hypothalamic-pituitary-adrenocortical and inflammation indices in BS of patients with focal epilepsy (FE) and epilepsy and comorbid depression (FE + MDD) and to compare them with those of patients with major depressive disorder (MDD) and healthy controls (HC). GDNF levels in BS were similar in patients and HC and higher in FE taking valproates. GDNF levels in LF were significantly lower in all patient groups compared to controls, and independent of drugs used. GDNF concentrations in LF and BS positively correlated in HC, but not in patient groups. BDNF level was lower in BS of patients compared with HC and higher in FE + MDD taking valproates. A reduction in the GDNF level in LF might be an important biomarker of FE. Logistic regression models demonstrated that the probability of FE can be evaluated using GDNF in LF and BDNF in BS; that of MDD using GDNF in LF and cortisol and TNF-α in BS; and that of epilepsy with MDD using GDNF in LF and TNF-α and BDNF in BS.

Further advances in epilepsy

In 2017, one of us reviewed advances in epilepsy (Manford in J Neurol 264:1811-1824, 2017). The current paper brings that review up to date and gives a slight change in emphasis. Once again, the story is of evolution rather than revolution. In recognition that most of our current medications act on neurotransmitters or ion channels, and not on the underlying changes in connectivity and pathways, they have been renamed as antiseizure (ASM) medications rather than antiepileptic drugs. Cenobamate is the one newly licensed medication for broader use in focal epilepsy but there have been a number of developments for specific disorders. We review new players and look forward to new developments in the light of evolving underlying science. We look at teratogenicity; old villains and new concerns in which clinicians play a vital role in explaining and balancing the risks. Medical treatment of status epilepticus, long without evidence, has benefitted from high-quality trials to inform practice; like buses, several arriving at once. Surgical treatment continues to be refined with improvements in the pre-surgical evaluation of patients, especially with new imaging techniques. Alternatives including stereotactic radiotherapy have received further focus and targets for palliative stimulation techniques have grown in number. Individuals' autonomy and quality of life continue to be the subject of research with refinement of what clinicians can do to help persons with epilepsy (PWE) achieve control. This includes seizure management but extends to broader considerations of human empowerment, needs and desires, which may be aided by emerging technologies such as seizure detection devices. The role of specialist nurses in improving that quality has been reinforced by specific endorsement from the International League against Epilepsy (ILAE).

Correlations between omega-3 fatty acids and inflammatory/glial abnormalities: the involvement of the membrane and neurotransmitter dysfunction in schizophrenia

Introduction

Macrophages or T-lymphocytes triggered inflammation and, consequently, activated glial cells may contribute to neuroinflammation and neurotransmitter dysfunction in schizophrenia (SZ), while omega(n)-3 polyunsaturated fatty acids (PUFAs) can attenuate some SZ symptoms through anti-inflammatory effects. However, the correlations between macrophage/T-lymphocyte-produced cytokines and glia phenotypes, between inflammatory status and PUFAs composition, between cytokines and neurotransmitter function, and between n-3 PUFAs and neurotransmitter abnormality in SZ are unclear.

Methods

Changes in T-helper (h) patterns, peripheral macrophage/glial markers, PUFAs profile, membrane fluidity, and neurotransmitter functions were evaluated in SZ patients (n = 50) and healthy controls (n = 30) using ELISA, gas chromatography, fluorescence anisotropy techniques, and HPLC, respectively.

Results

Compared to the control, blood lymphocyte proliferation, the concentration of macrophage/microglia phenotype M1 markers, including cytokines IL-1β, TNF-α (Th1) and IL-6 (Th2), and astrocyte phenotype A1 marker S100β was significantly increased, while IL-17 and n-3 PUFAs contents, n-3/n-6 ratio, and membrane fluidity (FLU) were significantly decreased in SZ. Moreover, increased DA and HVA, decreased 5-HT and NE, and their metabolites appeared in SZ. Moreover, negative correlations between IL-6 and A2 marker Brain-Derived Neurotrophic Factor (BDNF) or n-3 PUFAs EPA and between IL-1β and FLU or 5HIAA, while positive correlations between EPA and 5-HIAA and between FLU and DHA were found in SZ.

Discussion

These findings showed (1) no clear Th pattern, but pro-inflammatory-dominant immunity occurred; (2) the pro-inflammatory pattern may result in the activated microglia M1 and astrocyte A1 phenotype; and (3) increased pro-inflammatory cytokines were related to decreased n-3 PUFA and decreased membrane fluidity and dysfunctional neurotransmitter systems in SZ.

DNA Methylation Description of Hippocampus, Cortex, Amygdala, and Blood of Drug-Resistant Temporal Lobe Epilepsy

Epigenetic changes such as DNA methylation were observed in drug-resistant temporal lobe epilepsy (DR-TLE), a disease that affects 25-30% of epilepsy patients. The main objective is to simultaneously describe DNA methylation patterns associated with DR-TLE in hippocampus, amygdala, surrounding cortex to the epileptogenic zone (SCEZ), and peripheral blood. An Illumina Infinium MethylationEPIC BeadChip array was performed in 19 DR-TLE patients and 10 postmortem non-epileptic controls. Overall, 32, 59, and 3210 differentially methylated probes (DMPs) were associated with DR-TLE in the hippocampus, amygdala, and SCEZ, respectively. These DMP-affected genes were involved in neurotrophic and calcium signaling in the hippocampus and voltage-gated channels in SCEZ, among others. One of the hippocampus DMPs (cg26834418 (CHORDC1)) showed a strong blood-brain correlation with BECon and IMAGE-CpG, suggesting that it could be a potential surrogate peripheral biomarker of DR-TLE. Moreover, in three of the top SCEZ's DMPs (SHANK3, SBF1, and MCF2L), methylation status was verified with methylation-specific qPCR. The differentially methylated CpGs were classified in DMRs: 2 in the hippocampus, 12 in the amygdala, and 531 in the SCEZ. We identified genes that had not been associated to DR-TLE so far such as TBX5, EXOC7, and WRHN. The area with more DMPs associated with DR-TLE was the SCEZ, some of them related to voltage-gated channels. The DMPs found in the amygdala were involved in inflammatory processes. We also found a potential surrogate peripheral biomarker of DR-TLE. Thus, these results provide new insights into epigenetic modifications involved in DR-TLE.

Systemic inflammation as a biomarker of seizure propensity and a target for treatment to reduce seizure propensity

People with diabetes can wear a device that measures blood glucose and delivers just the amount of insulin needed to return the glucose level to within bounds. Currently, people with epilepsy do not have access to an equivalent wearable device that measures a systemic indicator of an impending seizure and delivers a rapidly acting medication or other intervention (e.g., an electrical stimulus) to terminate or prevent a seizure. Given that seizure susceptibility is reliably increased in systemic inflammatory states, we propose a novel closed-loop device where release of a fast-acting therapy is governed by sensors that quantify the magnitude of systemic inflammation. Here, we review the evidence that patients with epilepsy have raised levels of systemic indicators of inflammation than controls, and that some anti-inflammatory drugs have reduced seizure occurrence in animals and humans. We then consider the options of what might be incorporated into a responsive anti-seizure system.

Neuronal and astrocytic tetraploidy is increased in drug-resistant epilepsy

AIMS

Epilepsy is one of the most prevalent neurological diseases. A third of patients with epilepsy remain drug-resistant. The exact aetiology of drug-resistant epilepsy (DRE) is still unknown. Neuronal tetraploidy has been associated with neuropathology. The aim of this study was to assess the presence of tetraploid neurons and astrocytes in DRE.

METHODS

For that purpose, cortex, hippocampus and amygdala samples were obtained from patients subjected to surgical resection of the epileptogenic zone. Post-mortem brain tissue of subjects without previous records of neurological, neurodegenerative or psychiatric diseases was used as control.

RESULTS

The percentage of tetraploid cells was measured by immunostaining of neurons (NeuN) or astrocytes (S100β) followed by flow cytometry analysis. The results were confirmed by image cytometry (ImageStream X Amnis System Cytometer) and with an alternative astrocyte biomarker (NDRG2). Statistical comparison was performed using univariate tests. A total of 22 patients and 10 controls were included. Tetraploid neurons and astrocytes were found both in healthy individuals and DRE patients in the three brain areas analysed: cortex, hippocampus and amygdala. DRE patients presented a higher number of tetraploid neurons (p = 0.020) and astrocytes (p = 0.002) in the hippocampus than controls. These results were validated by image cytometry.

CONCLUSIONS

We demonstrated the presence of both tetraploid neurons and astrocytes in healthy subjects as well as increased levels of both cell populations in DRE patients. Herein, we describe for the first time the presence of tetraploid astrocytes in healthy subjects. Furthermore, these results provide new insights into epilepsy, opening new avenues for future treatment.

Gene expression profile suggests different mechanisms underlying sporadic and familial mesial temporal lobe epilepsy

Most patients with pharmacoresistant mesial temporal lobe epilepsy (MTLE) have hippocampal sclerosis on the postoperative histopathological examination. Although most patients with MTLE do not refer to a family history of the disease, familial forms of MTLE have been reported. We studied surgical specimens from patients with MTLE who had epilepsy surgery for medically intractable seizures. We assessed and compared gene expression profiles of the tissue lesion found in patients with familial MTLE (n = 3) and sporadic MTLE (n = 5). In addition, we used data from control hippocampi obtained from a public database (n = 7). We obtained expression profiles using the Human Genome U133 Plus 2.0 (Affymetrix) microarray platform. Overall, the molecular profile identified in familial MTLE differed from that in sporadic MTLE. In the tissue of patients with familial MTLE, we found an over-representation of the biological pathways related to protein response, mRNA processing, and synaptic plasticity and function. In sporadic MTLE, the gene expression profile suggests that the inflammatory response is highly activated. In addition, we found enrichment of gene sets involved in inflammatory cytokines and mediators and chemokine receptor pathways in both groups. However, in sporadic MTLE, we also found enrichment of epidermal growth factor signaling, prostaglandin synthesis and regulation, and microglia pathogen phagocytosis pathways. Furthermore, based on the gene expression signatures, we identified different potential compounds to treat patients with familial and sporadic MTLE. To our knowledge, this is the first study assessing the mRNA profile in surgical tissue obtained from patients with familial MTLE and comparing it with sporadic MTLE. Our results clearly show that, despite phenotypic similarities, both forms of MTLE present distinct molecular signatures, thus suggesting different underlying molecular mechanisms that may require distinct therapeutic approaches.

Blood biomarkers in epilepsy

Robust and accessible biomarkers are greatly needed in epilepsy. Diagnostic and prognostic precision in the clinic needs to improve, and there is a need for objective quantification of seizure burden. In recent years, there have been advances in the development of accessible and cost-effective blood-based biomarkers in neurology, and these are increasingly studied in epilepsy. However, the field is in its infancy and specificity and sensitivity for most biomarkers in most clinical situations are not known. This review describes advancements regarding human blood biomarkers in epilepsy. Examples of biochemical markers that have been shown to have higher blood concentrations in study subjects with epilepsy include brain proteins like S100B or neuronal specific enolase, and neuroinflammatory proteins like interleukins, and tumor necrosis factor-alpha. Some of the blood biomarkers also seem to reflect seizure duration or frequency, and levels decrease in response to treatment with antiseizure medication. For most biomarkers, the literature contains seemingly conflicting results. This is to be expected in an emerging field and could reflect different study populations, sampling or analysis techniques, and epilepsy classification. More studies are needed with emphasis put on the classification of epilepsy and seizure types. More standardized reporting could perhaps decrease result heterogeneity and increase the potential for data sharing and subgroup analyses.

Elevated Serum Cortisol Levels in Patients with Focal Epilepsy, Depression, and Comorbid Epilepsy and Depression

Background: The hypothalamic-pituitary-adrenal (HPA) axis, inflammatory processes and neurotrophic factor systems are involved in pathogenesis of both epilepsy and depressive disorders. The study aimed to explore these systems in patients with focal epilepsy (PWE, n = 76), epilepsy and comorbid depression (PWCED n = 48), and major depressive disorder (PWMDD, n = 62) compared with healthy controls (HC, n = 78). Methods: Parameters of the HPA axis, neurotrophic factors, and TNF-α were measured in blood serum along with the hemogram. Results: Serum cortisol level was augmented in PWE, PWCED, and PWMDD compared with HC and was higher in PWMDD than in PWE. Serum cortisol negatively correlated with Mini–Mental State Examination (MMSE) score in PWE, and positively with depression inventory–II (BDI-II) score in PWMDD. Only PWMDD demonstrated elevated plasma ACTH. Serum TNF-α, lymphocytes, and eosinophils were augmented in PWMDD; monocytes elevated in PWE and PWCED, while neutrophils were reduced in PWE and PWMDD. Serum BDNF was decreased in PWE and PWCED, CNTF was elevated in all groups of patients. In PWE, none of above indices depended on epilepsy etiology. Conclusions: The results confirm the involvement of HPA axis and inflammatory processes in pathogenesis of epilepsy and depression and provide new insights in mechanisms of epilepsy and depression comorbidity.

The role of interleukin-17 in epilepsy

Epilepsy is a common neurological disorder that seriously affects human health. It is a chronic central nervous system dysfunction caused by abnormal discharges of neurons. About 50 million patients worldwide are affected by epilepsy. Although epileptic symptoms of most patients are controllable, some patients with refractory epilepsy have no response to antiseizure medications. It is necessary to investigate the pathogenesis of epilepsy and identify new therapeutic targets for refractory epilepsy. Epileptic disorders often accompany cerebral inflammatory reactions. Recently, the role of inflammation in the onset of epilepsy has increasingly attracted attention. The activation of both innate and adaptive immunity plays a significant role in refractory epilepsy. According to several clinical studies, interleukin-17, an essential inflammatory mediator linking innate and adaptive immunity, increased significantly in the body liquid and epileptic focus of patients with epilepsy. Experimental studies also indicated that interleukin-17 participated in epileptogenesis through various mechanisms. This review summarized the current studies about interleukin-17 in epilepsy and aimed at finding new therapeutic targets for refractory epilepsy.

The Coordination of mTOR Signaling and Non-Coding RNA in Regulating Epileptic Neuroinflammation

Epilepsy accounts for a significant proportion of the burden of neurological disorders. Neuroinflammation acting as the inflammatory response to epileptic seizures is characterized by aberrant regulation of inflammatory cells and molecules, and has been regarded as a key process in epilepsy where mTOR signaling serves as a pivotal modulator. Meanwhile, accumulating evidence has revealed that non-coding RNAs (ncRNAs) interfering with mTOR signaling are involved in neuroinflammation and therefore articipate in the development and progression of epilepsy. In this review, we highlight recent advances in the regulation of mTOR on neuroinflammatory cells and mediators, and feature the progresses of the interaction between ncRNAs and mTOR in epileptic neuroinflammation.

Immune Mechanism of Epileptogenesis and Related Therapeutic Strategies

Immunologic and neuroinflammatory pathways have been found to play a major role in the pathogenesis of many neurological disorders such as epilepsy, proposing the use of novel therapeutic strategies. In the era of personalized medicine and in the face of the exhaustion of anti-seizure therapeutic resources, it is worth looking at the current or future possibilities that neuroimmunomodulator or anti-inflammatory therapy can offer us in the management of patients with epilepsy. For this reason, we performed a narrative review on the recent advances on the basic epileptogenic mechanisms related to the activation of immunity or neuroinflammation with special attention to current and future opportunities for novel treatments in epilepsy. Neuroinflammation can be considered a universal phenomenon and occurs in structural, infectious, post-traumatic, autoimmune, or even genetically based epilepsies. The emerging research developed in recent years has allowed us to identify the main molecular pathways involved in these processes. These molecular pathways could constitute future therapeutic targets for epilepsy. Different drugs current or in development have demonstrated their capacity to inhibit or modulate molecular pathways involved in the immunologic or neuroinflammatory mechanisms described in epilepsy. Some of them should be tested in the future as possible antiepileptic drugs.

Sleep Disruption Worsens Seizures: Neuroinflammation as a Potential Mechanistic Link

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