Relationship between chronic hypoxia and seizure susceptibility

Screening, Analysis, and Validation of Endoplasmic Reticulum Stress-Related DEGs in Epilepsy

To investigate the relationship between Endoplasmic Reticulum Stress (ERS) and epilepsy, as well as their biological functions. We downloaded the GSE143272 dataset from the GEO database, identified differentially expressed genes (DEGs), and cross-analyzed them with ERS-related genes from GeneCards and the Molecular Signatures Database (MSigDB). Protein-protein interaction (PPI) networks were constructed, and Hub genes were screened. ROC curve analysis was conducted to assess the diagnostic utility of these genes, followed by qRT-PCR validation. This study identified a total of 83 ERS-related DEGs in epilepsy. PPI network analysis revealed eight feature genes: C-X-C motif chemokine ligand 8 (CXCL8), Toll-like receptor 4 (TLR4), Matrix metalloproteinase 9 (MMP9), Tumor necrosis factor receptor superfamily member 1A (TNFRSF1A), Prostaglandin-endoperoxide synthase 2 (PTGS2), Signal transducer and activator of transcription 1 (STAT1), B-cell lymphoma 2 (BCL2), and RELA proto-oncogene, NF-κB subunit (RELA). ROC curve analysis demonstrated that the combination of these eight feature genes exhibited the highest diagnostic potential. Among them, CXCL8 was the most valuable gene. qRT-PCR analysis showed that CXCL8 mRNA expression was significantly lower in the case group compared to the control group (P < 0.01). The results suggest that ERS is involved in physiological processes such as inflammation and neuronal apoptosis in epilepsy. This provides a bioinformatics evidence for exploring the biological functions and pathology of ERS in epilepsy, as well as serving as a reference for clinical diagnosis and potential therapeutic targets.

The Dynamics of Seizures After Microsurgical Treatment of Brain AVMs in Patients with Symptomatic Epilepsy: A Single-Center Experience over 10 Years

Background and Objectives: Arteriovenous malformations (AVMs) are abnormal connections between arteries and veins, lacking a normal capillary network. Seizures are a common clinical manifestation in patients with brain AVMs, ranking as the second most frequent presentation. The objective of this study was to evaluate the dynamics of seizure activity in patients with brain AVMs following surgical treatment. Materials and Methods: This study included 27 patients with brain AVMs who underwent microsurgical AVM resection for symptomatic epilepsy. All surgical interventions were performed at JSC "National Centre for Neurosurgery" between 2008 and 2020. Results: Over an average follow-up period of 98.07 ± 45.6 months, 82 patients with brain AVMs underwent open microsurgical resection at the National Centre for Neurosurgery. Among them, 27 patients presented with seizures and had complete follow-up information, qualifying them for inclusion in this study. The participants had a mean age of 32.59 ± 9.06 years, with 13 of them being women. The Spetzler-Martin grading system was used to classify the AVMs: 6 patients had grade 1, 13 had grade 2, 7 had grade 3, and 1 had grade 4. More than half of the patients experienced generalized seizures. Microsurgical removal of the AVMs resulted in seizure remission for all patients. Only one patient experienced postoperative hemorrhage during the follow-up period. Additionally, one patient developed acute postoperative anemia, which resolved with a favorable outcome. Conclusions: Microsurgical resection of brain AVMs, when performed with careful patient selection, leads to a significant reduction in seizure activity. It is a safe and effective treatment option for symptomatic epilepsy associated with brain AVMs.

The temporal-insula type of temporal plus epilepsy patients with different postoperative seizure outcomes have different cerebral blood flow patterns

PURPOSE

This study retrospectively analyzed preoperative arterial spin labeling (ASL) perfusion MRI data of patients with the temporal-insula type of temporal plus epilepsy (TI-TPE). We aimed to investigate the differences in presurgical cerebral blood flow (CBF) changes in TI-TPE patients with different surgical outcomes.

METHOD

A total of 48 TI-TPE patients confirmed by SEEG were meticulously reviewed for this study. Patients were divided into the seizure-free (SF) group (Engel IA) and the non-seizure-free (NSF) group (Engel IB to IV) according to the Engel seizure classification. The 3D-ASL data of all patients before surgery were analyzed using statistical parametric mapping (SPM) and graph theory analysis. These findings were then compared to healthy controls (HC) based on whole-brain voxel-level analysis and covariance network analysis.

RESULT

At the voxel-level, both SF and NSF groups showed significantly decreased CBF in the ipsilateral transverse temporal gyrus and insula (TTG/insula), contralateral middle cingulate gyrus, precuneus (MCG/precuneus), and increased CBF in the ipsilateral superior temporal gyrus and the superior temporal pole (STG/STP). Wherein the SF group showed more lower CBF in the contralateral MCG/precuneus, with unique increased CBF in the contralateral STG/insula and decreased CBF in the contralateral calcarine as well. In terms of network attributes, the NSF group showed a significantly higher clustering coefficient (Cp), global efficiency (Eglob), local efficiency (Eloc), shorter shortest path length (Lp), and more extensive abnormal nodes compared to the SF and HC groups. While the SF group has higher synchronicity than the HC group.

CONCLUSION

Both SF and NSF groups had abnormal CBF changes at the voxel and network levels with different patterns. The SF group showed more obvious regional CBF changes, while the NSF group showed more extended network disruption, which might underlie different seizure outcomes after local surgical resection.

Transcriptomic and morphologic vascular aberrations underlying FCDIIb etiology

Focal cortical dysplasia type II (FCDII) is a major cause of drug-resistant epilepsy, but genetic factors explain only some cases, suggesting other mechanisms. In this study, we conduct a molecular analysis of brain lesions and adjacent areas in FCDIIb patients. By analyzing over 217,506 single-nucleus transcriptional profiles from 15 individuals, we find significant changes in smooth muscle cells (SMCs) and astrocytes. We identify abnormal vascular malformations and a unique type of SMC that we call "Firework cells", which migrate from blood vessels into the brain parenchyma and associate with VIM+ cells. These abnormalities create localized ischemic-hypoxic (I/H) microenvironments, as confirmed by clinical data, further impairing astrocyte function, activating the HIF-1α/mTOR/S6 pathway, and causing neuronal loss. Using zebrafish models, we demonstrate that vascular abnormalities resulting in I/H environments promote seizures. Our results highlight vascular malformations as a factor in FCDIIb pathogenesis, suggesting potential therapeutic avenues.

Etiological features of status epilepticus of the in-patient cohort in Tibet: A retrospective comparative study

BACKGROUND

The etiology of status epilepticus (SE) in Tibet has not yet been reported. We aimed to establish the etiological baseline of SE in the Tibet Autonomous Region in China and compare it with a SE cohort from a regional neuroscience centre in Sichuan, Southwestern China to reveal whether there was a unique etiology distribution in the Tibetan region.

METHODS

We retrospectively captured clinical data of patients diagnosed with SE in the People's Hospital of Xizang Autonomous Region from January 2015 to December 2020. Control data were recorded during the same period from West China Hospital of Sichuan University, Sichuan Province. Clinical and etiology evaluations were conducted by 4 neurologists using a standard case report form.

RESULTS

A total of 619 patients were enrolled, among whom 318 were from the Tibetan cohort. The median age of the Tibetan cohort was 37.5 years, with 109 (34.3%) being women. The main etiology in the Tibetan cohort was uncontrolled persistent epilepsy (70.1%, N = 223). Compared to the control cohort, the proportion of patients in Tibet whose SE could be controlled was higher (97.5% vs 81.1%, p<.001) and the proportion of patients with refractory SE was lower (8.8% vs 35.2%, p<.001). Among the 223 patients with epilepsy who developed SE, 111 had never been treated with anti-seizure medication, and 52 (23.3%) were judged only to have received inappropriate treatment of epilepsy. Forty patients (17.9%) were only receiving treatment with traditional Tibetan medicine for epilepsy prior to admission. Patients with epilepsy of infectious etiology were seen in 37 patients in Tibetan cohort. In twenty-eight patients neurocysticercosis was identified as the cause of epilepsy. And in two patients, the cause of epilepsy was brain hydatid.

CONCLUSIONS

The main etiology of SE in the Tibet Autonomous Region was unsatisfactory seizure control in patients with pre-existing epilepsy, while a greater proportion of epilepsy due to infectious causes was noted. Improved education for physicians and patients is needed to improve the management of epilepsy and SE in this population.

Correlation between selenium levels and selenoproteins expression in idiopathic generalized epilepsy: a study from Karachi

BACKGROUND

Oxidative damage has been implicated in multiple neurodegenerative diseases, including epilepsy. Selenium, in the form of selenoproteins is an integral part of the human antioxidant defense system. Though a relationship between the altered selenium levels and epilepsy has been reported, limited evidence is available about the expression pattern of selenoproteins in epileptic patients.

OBJECTIVE

This study aimed to determine the serum selenium levels in idiopathic epileptic and healthy individuals. Expression profiling of selenoproteins (GPx1, TRxR1 and SEPW1) both at mRNA and protein levels was also evaluated.

METHODS

Serum selenium levels of 30 patients with idiopathic generalized epilepsy and their age and gender matched 30 healthy controls were measured. Protein levels of Serum Glutathione Peroxidase 1 (GPx1), Thioredoxin Reductase 1 (TRxR1) and Selenoprotein W (SEPW1) were estimated using ELISA. mRNA expression of GPx1, TRxR1 and SEPW1 were determined using qRT-PCR.

RESULTS

The mean values for serum selenium levels in cases and controls were 37.6 ± 2.0 µmol/ml and 38.9 ± 2.7 µmol/ml, respectively. Selenium levels in cases were significantly lower as compared to controls (p = 0.031). No statistically significant differences were observed between the serum levels of selenoproteins GPx1, TRxR1 and SEPW1 in epileptic patients and the healthy group. GPx1 and TRxR1 expression was found to be down regulated (0.34 and 0.13 folds respectively) whereas SEPW 1 was found to be 0.04 folds up regulated in epileptic patients compared to the healthy subjects.

CONCLUSION

Selenium deficiency observed in epileptic patients suggests the association between serum selenium levels and epilepsy. This study provides the information about the selenium status in Pakistani population and helps in understanding the role of selenium in the prevention of epilepsy.

A Dangerous Hiding Spot: The Unrecognized Danger Posed by Child-Sized Helium Balloons

Anticipatory guidance on balloons typically highlights the danger of choking on uninflated balloon fragments. One type of balloon injury that is not widely discussed is suffocation due to crawling inside a large foil helium-containing balloon. A six-year-old female presented to a community hospital emergency department (ED) after being found on the floor inside a 50-inch foil balloon in the shape of the number "7." The patient's mother found her unconscious, limp, and with no spontaneous respirations. She initiated chest compressions before emergency medical services arrived. After evaluation and treatment in the community hospital ED, the patient was transferred to a tertiary children's hospital for observation and frequent neurological checks. She returned fully to baseline mental status 12 hours after the injury and was discharged home later that same day. This case highlights that oversized balloons can be enticing but hazardous hiding spots for children and discusses several possible mechanisms of injury. Parents and pediatricians should be aware of the dangers of suffocation in these cases.

Therapeutic potential of ketamine in management of epilepsy: Clinical implications and mechanistic insights

Epilepsy, a widespread neurological disorder, affects approximately 50 million people worldwide. This disorder is typified by recurring seizures due to abnormal neuron communication in the brain. The seizures can lead to severe ischemia and hypoxia, potentially threatening patients' lives. However, with proper diagnosis and treatment, up to 70 % of patients can live without seizures. The causes of epilepsy are complex and multifactorial, encompassing genetic abnormalities, structural brain anomalies, ion channel dysfunctions, neurotransmitter imbalances, neuroinflammation, and immune system involvement. These factors collectively disrupt the crucial balance between excitation and inhibition within the brain, leading to epileptic seizures. The management of treatment-resistant epilepsy remains a considerable challenge, necessitating innovative therapeutic approaches. Among emerging potential treatments, ketamine-a drug traditionally employed for anesthesia and depression-has demonstrated efficacy in reducing seizures. It is noteworthy that, independent of its anti-epileptic effects, ketamine has been found to improve the balance between excitatory and inhibitory (E/I) activities in the brain. The balance is crucial for maintaining normal neural function, and its disruption is widely considered a key driver of epileptic seizures. By acting on N-methyl-D-aspartate (NMDA) receptors and other potential mechanisms, ketamine may regulate neuronal excitability, reduce excessive synchronized neural activity, and counteract epileptic seizures. This positive impact on E/I balance reinforces the potential of ketamine as a promising drug for treating epilepsy, especially in patients who are insensitive to traditional anti-epileptic drugs. This review aims to consolidate the current understanding of ketamine's therapeutic role in epilepsy. It will focus its impact on neuronal excitability and synaptic plasticity, its neuroprotective qualities, and elucidate the drug's potential mechanisms of action in treating epilepsy. By scrutinizing ketamine's impact and mechanisms in various types of epilepsy, we aspire to contribute to a more comprehensive and holistic approach to epilepsy management.

[Amplitude-integrated electroencephalography monitoring results of hospitalized neonates in plateau areas]

OBJECTIVES

To investigate the amplitude-integrated electroencephalography (aEEG) monitoring results of hospitalized neonates in plateau areas.

METHODS

A retrospective analysis was conducted on 5 945 neonates who were admitted to the Department of Neonatology, Kunming Children's Hospital, and received aEEG monitoring from January 2020 to December 2022. According to the aEEG monitoring results, they were divided into a normal aEEG group and an abnormal aEEG group. The incidence rate of aEEG abnormalities was analyzed in neonates with various systemic diseases, as well as the manifestations of aEEG abnormalities and the consistency between aEEG abnormalities and clinical abnormalities.

RESULTS

Among the 5 945 neonates, the aEEG abnormality rate was 19.28% (1 146/5 945), with an abnormality rate of 29.58% (906/3 063) in critically ill neonates and 8.33% (240/2 882) in non-critically ill neonates (P<0.05). The children with inherited metabolic diseases showed the highest aEEG abnormality rate of 60.77% (79/130), followed by those with central nervous system disorders [42.22% (76/180)] and preterm infants [35.53% (108/304)]. Compared with the normal aEEG group, the abnormal aEEG group had significantly lower age and gestational age, as well as a significantly lower birth weight of preterm infants (P<0.05). Among the 1 146 neonates with aEEG abnormalities, the main types of aEEG abnormalities were sleep cycle disorders in 597 neonates (52.09%), background activity abnormalities in 294 neonates (25.65%), and epileptiform activity in 255 neonates (22.25%), and there were 902 neonates (78.71%) with abnormal clinical manifestations. The sensitivity and specificity of aEEG monitoring for brain function abnormalities were 33.51% and 92.50%, respectively.

CONCLUSIONS

In plateau areas, there is a relatively high rate of aEEG abnormalities among hospitalized neonates, particularly in critically ill neonates and those with smaller gestational ages and younger ages, suggesting a high risk of brain injury. Therefore, routine aEEG monitoring for the hospitalized neonates can help with the early detection of brain function abnormalities, the decision-making in treatment, and the formulation of brain protection strategies.

Chronic Sustained Hypoxia Leads to Brainstem Tauopathy and Declines the Power of Rhythms in the Ventrolateral Medulla: Shedding Light on a Possible Mechanism

Hypoxia, especially the chronic type, leads to disruptive results in the brain that may contribute to the pathogenesis of some neurodegenerative diseases such as Alzheimer's disease (AD). The ventrolateral medulla (VLM) contains clusters of interneurons, such as the pre-Bötzinger complex (preBötC), that generate the main respiratory rhythm drive. We hypothesized that exposing animals to chronic sustained hypoxia (CSH) might develop tauopathy in the brainstem, consequently changing the rhythmic manifestations of respiratory neurons. In this study, old (20-22 months) and young (2-3 months) male rats were subjected to CSH (10 ± 0.5% O2) for ten consecutive days. Western blotting and immunofluorescence (IF) staining were used to evaluate phosphorylated tau. Mitochondrial membrane potential (MMP or ∆ψm) and reactive oxygen species (ROS) production were measured to assess mitochondrial function. In vivo diaphragm's electromyography (dEMG) and local field potential (LFP) recordings from preBötC were employed to assess the respiratory factors and rhythmic representation of preBötC, respectively. Findings showed that ROS production increased significantly in hypoxic groups, associated with a significant decline in ∆ψm. In addition, tau phosphorylation elevated in the brainstem of hypoxic groups. On the other hand, the power of rhythms declined significantly in the preBötC of hypoxic rats, parallel with changes in the respiratory rate, total respiration time, and expiration time. Moreover, there was a positive and statistically significant correlation between LFP rhythm's power and inspiration time. Our data showed that besides CSH, aging also contributed to mitochondrial dysfunction, tau hyperphosphorylation, LFP rhythms' power decline, and changes in respiratory factors.

Unexplained Causes of Glioma-Associated Epilepsies: A Review of Theories and an Area for Research

Approximately 30% of glioma patients are able to survive beyond one year postdiagnosis. And this short time is often overshadowed by glioma-associated epilepsy. This condition severely impairs the patient's quality of life and causes great suffering. The genetic, molecular and cellular mechanisms underlying tumour development and epileptogenesis remain incompletely understood, leading to numerous unanswered questions. The various types of gliomas, namely glioblastoma, astrocytoma and oligodendroglioma, demonstrate distinct seizure susceptibility and disease progression patterns. Patterns have been identified in the presence of IDH mutations and epilepsy, with tumour location in cortical regions, particularly the frontal lobe, showing a more frequent association with seizures. Altered expression of TP53, MGMT and VIM is frequently detected in tumour cells from individuals with epilepsy associated with glioma. However, understanding the pathogenesis of these modifications poses a challenge. Moreover, hypoxic effects induced by glioma and associated with the HIF-1a factor may have a significant impact on epileptogenesis, potentially resulting in epileptiform activity within neuronal networks. We additionally hypothesise about how the tumour may affect the functioning of neuronal ion channels and contribute to disruptions in the blood-brain barrier resulting in spontaneous depolarisations.

Differential metabolic alterations in IDH1 mutant vs. wildtype glioma cells promote epileptogenesis through distinctive mechanisms

Glioma-related epilepsy (GRE) is a hallmark clinical presentation of gliomas with significant impacts on patient quality of life. The current standard of care for seizure management is comprised of anti-seizure medications (ASMs) and surgical resection. Seizures in glioma patients are often drug-resistant and can often recur after surgery despite total tumor resection. Therefore, current research is focused on the pro-epileptic pathological changes occurring in tumor cells and the peritumoral environment. One important contribution to seizures in GRE patients is metabolic reprogramming in tumor and surrounding cells. This is most evident by the significantly heightened seizure rate in patients with isocitrate dehydrogenase mutated (IDHmut) tumors compared to patients with IDH wildtype (IDHwt) gliomas. To gain further insight into glioma metabolism in epileptogenesis, this review compares the metabolic changes inherent to IDHmut vs. IDHwt tumors and describes the pro-epileptic effects these changes have on both the tumor cells and the peritumoral environment. Understanding alterations in glioma metabolism can help to uncover novel therapeutic interventions for seizure management in GRE patients.

Association of patent foramen ovale with epilepsy: A hospital-based case-control study

OBJECTIVE

This study aimed to investigate the proportion of patent foramen ovale (PFO) in people with epilepsy (PWE) compared to controls without epilepsy and to assess whether PWEs with and without PFO exhibit distinctive clinical features.

METHODS

This is a case-control study conducted in a hospital. Contrast transthoracic echocardiography with a venous microbubble bolus and provocative maneuvers (Valsalva and coughing) were used to identify PFO and its right-to-left shunt (RLS) among 741 PWEs and 800 controls without epilepsy. The risk of having PFO in PWEs was explored using multiple matching methods and logistic regression with adjusted congenital factors that may affect the occurrence of PFO.

RESULTS

The proportion of PFO in PWEs and controls was 39.00% and 24.25%, respectively. After 1:1 propensity score matching, the risk of suffering PFO in PWEs was 1.71 times (OR, 1.71; 95% CI, 1.24-2.36) higher than that in controls. PWEs also had a higher risk of having a high RLS grade (βepilepsy  = 0.390, P < 0.001). Among clinical characteristics of PWEs, migraine, and drug-resistant epilepsy showed significantly different distributions between those without RLS and those with RLS grade I to III. PWEs with PFO had higher risk of suffering from migraine and drug-resistant epilepsy (OR in migraine, 2.54, 95% CI, 1.65-3.95; OR in drug-resistant epilepsy, 1.47, 95% CI, 1.06-2.03).

SIGNIFICANCE

The proportion of PFO was found to be higher in PWE than in controls without epilepsy, especially in patients with drug-resistant epilepsy, suggesting potential relationship between the two disorders. Large multicentric study will be needed to confirm this finding.

Alteration of functional connectivity despite preserved cerebral oxygenation during acute hypoxia

Resting state networks (RSN), which show the connectivity in the brain in the absence of any stimuli, are increasingly important to assess brain function. Here, we investigate the changes in RSN as well as the hemodynamic changes during acute, global hypoxia. Mice were imaged at different levels of oxygen (21, 12, 10 and 8%) over the course of 10 weeks, with hypoxia and normoxia acquisitions interspersed. Simultaneous GCaMP and intrinsic optical imaging allowed tracking of both neuronal and hemodynamic changes. During hypoxic conditions, we found a global increase of both HbO and HbR in the brain. The saturation levels of blood dropped after the onset of hypoxia, but surprisingly climbed back to levels similar to baseline within the 10-min hypoxia period. Neuronal activity also showed a peak at the onset of hypoxia, but dropped back to baseline as well. Despite regaining baseline sO2 levels, changes in neuronal RSN were observed. In particular, the connectivity as measured with GCaMP between anterior and posterior parts of the brain decreased. In contrast, when looking at these same connections with HbO measurements, an increase in connectivity in anterior-posterior brain areas was observed suggesting a potential neurovascular decoupling.

Calcium Phosphate-Based Nanoformulation Selectively Abolishes Phenytoin Resistance in Epileptic Neurons for Ceasing Seizures

Phenytoin (PHT) is a first-line antiepileptic drug in clinics, which could decrease neuronal bioelectric activity by blocking the voltage-operated sodium channels. However, the intrinsically low blood-brain-barrier (BBB)-crossing capability of PHT and upregulated expression level of the efflux transporter p-glycoprotein (P-gp) coded by the gene Abcb1 in epileptic neurons limit its efficacy in vivo. Herein, a nanointegrated strategy to overcome PHT resistance mechanisms for enhanced antiepileptic efficacy is reported. Specifically, PHT is first incorporated into calcium phosphate (CaP) nanoparticles through biomineralization, followed by the surface modification of the PEGylated BBB-penetrating TAT peptide. The CaP@PHT-PEG-TAT nanoformulation could effectively cross the BBB to be taken in by epileptic neurons. Afterward, the acidic lysosomal environment would trigger their complete degradation to release Ca²⁺ and PHT into the cytosol. Ca²⁺ ions would inhibit mitochondrial oxidative phosphorylation to reverse cellular hypoxia to block hypoxia-inducible factor-1α (Hif1α)-Abcb1-axis, as well as disrupt adenosine triphosphate generation, leading to simultaneous suppression of the expression and drug efflux capacity of P-gp to enhance PHT retention. This study offers an approach for effective therapeutic intervention against drug-resistant epilepsy.