Form Of Drug-resistant Epilepsy Research Articles

Discovery of Potent and Selective Blockers Targeting the Epilepsy-Associated KNa1.1 Channel.

Gain-of-function (GOF) mutations of the sodium-activated potassium channel KNa1.1 (Slack, Slo2.2, or KCa4.1) induce severe, drug-resistant forms of epilepsy in infants and children. Although quinidine has shown promise in treating KCNT1-related epilepsies compared to other drugs, its limited efficacy and substantial side effects necessitate the development of new KNa1.1 channel inhibitors. In this study, we developed a novel class of KNa1.1 inhibitors using combined silico approaches and structural optimization. Among these inhibitors, compound Z05 was identified as a selective potential KNa1.1 inhibitor, especially against the hERG channel. Moreover, its binding site and potential counteraction to a GOF mutant Y796H were identified by the mutation studies. Our data also showed that Z05 had significant pharmacological profiles, including high brain penetration and moderate oral bioavailability, offering a valuable in vitro tool compound for further drug development in treating KCNT1-related epilepsies.

Deep brain stimulation of hippocampus in treatment of refractory temporal lobe epilepsy.

Temporal lobe epilepsy (TLE) is the most common cause of focal onset seizures, affecting 40% of adolescents and adults with epilepsy. TLE is also one of the most common drug resistant forms of epilepsy. Surgical resection remains the treatment of choice for TLE, but not all patients with TLE are suitable candidates for resective neurosurgery. For such patients, deep brain stimulation (DBS) of the hippocampus remains a reversible and efficient treatment alternative. We undertook a systematic review of the literature on hippocampal DBS efficacy and safety in the management of patients with TLE. A search using two electronic databases, the Medical Literature, Analysis, and Retrieval System on-line (MEDLINE) and the Cochrane Central Register of Controlled Trials (CEN-TRAL), was conducted. We found 14 articles related to hippocampal DBS for the treatment of TLE. The responder rate (defined as at least 50% reduction in seizure frequency) for all patients was 83.4%, Of 99 patients treated by hippocampal DBS, 82 were regarded as responders, and 17 as non-responders. Hippocampal DBS appears to be a safe and efficacious treatment alternative for patients who are not candidates for temporal lobectomy or selective amygdalohippocampectomy due to serious postoperative cognitive deficits. In selected patients with TLE, this neuromodulatory therapy may be very safe and efficacious.

In Silico Assisted Identification, Synthesis, and In Vitro Pharmacological Characterization of Potent and Selective Blockers of the Epilepsy-Associated KCNT1 Channel.

Gain-of-function (GoF) variants in KCNT1 channels cause severe, drug-resistant forms of epilepsy. Quinidine is a known KCNT1 blocker, but its clinical use is limited due to severe drawbacks. To identify novel KCNT1 blockers, a homology model of human KCNT1 was built and used to screen an in-house library of compounds. Among the 20 molecules selected, five (CPK4, 13, 16, 18, and 20) showed strong KCNT1-blocking ability in an in vitro fluorescence-based assay. Patch-clamp experiments confirmed a higher KCNT1-blocking potency of these compounds when compared to quinidine, and their selectivity for KCNT1 over hERG and Kv7.2 channels. Among identified molecules, CPK20 displayed the highest metabolic stability; this compound also blocked KCNT2 currents, although with a lower potency, and counteracted GoF effects prompted by 2 recurrent epilepsy-causing KCNT1 variants (G288S and A934T). The present results provide solid rational basis for future design of novel compounds to counteract KCNT1-related neurological disorders.

In vitro human cell culture models in a bench-to-bedside approach to epilepsy.

Epilepsy is the most common chronic neurological disease, affecting nearly 1%-2% of the world's population. Current pharmacological treatment and regimen adjustments are aimed at controlling seizures; however, they are ineffective in one-third of the patients. Although neuronal hyperexcitability was previously thought to be mainly due to ion channel alterations, current research has revealed other contributing molecular pathways, including processes involved in cellular signaling, energy metabolism, protein synthesis, axon guidance, inflammation, and others. Some forms of drug-resistant epilepsy are caused by genetic defects that constitute potential targets for precision therapy. Although such approaches are increasingly important, they are still in the early stages of development. This review aims to provide a summary of practical aspects of the employment of invitro human cell culture models in epilepsy diagnosis, treatment, and research. First, we briefly summarize the genetic testing that may result in the detection of candidate pathogenic variants in genes involved in epilepsy pathogenesis. Consequently, we review existing invitro cell models, including induced pluripotent stem cells and differentiated neuronal cells, providing their specific properties, validity, and employment in research pipelines. We cover two methodological approaches. The first approach involves the utilization of somatic cells directly obtained from individual patients, while the second approach entails the utilization of characterized cell lines. The models are evaluated in terms of their research and clinical benefits, relevance to the invivo conditions, legal and ethical aspects, time and cost demands, and available published data. Despite the methodological, temporal, and financial demands of the reviewed models they possess high potential to be used as robust systems in routine testing of pathogenicity of detected variants in the near future and provide a solid experimental background for personalized therapy of genetic epilepsies. PLAIN LANGUAGE SUMMARY: Epilepsy affects millions worldwide, but current treatments fail for many patients. Beyond traditional ion channel alterations, various genetic factors contribute to the disorder's complexity. This review explores how invitro human cell models, either from patients or from cell lines, can aid in understanding epilepsy's genetic roots and developing personalized therapies. While these models require further investigation, they offer hope for improved diagnosis and treatment of genetic forms of epilepsy.

Possibilities of stimulating epileptic seizures using deep stereo-EEG electrodes in presurgical diagnosis in patients with drug-resistant epilepsy

Electrical stimulation mapping using depth stereo-EEG electrodes is an important method in the structure of presurgical diagnostics in patients with drug-resistant forms of epilepsy. Electrical stimulation mapping was first used in the 1960s and has been actively developed since then, but despite such a long history, a unified protocol for the use of this technique has not been developed and different approaches to stimulation mapping are used in different countries. Based on publications on the topic in PubMed and other available resources, we tried to briefly outline the current opinion on the significance of this technique, paying special attention to the methodological approaches of different schools to stimulation parameters when mapping epileptogenic zones, highlighting in a separate section approaches to stimulation of functionally significant zones Finally, we summarize data on the effectiveness of this method in the presurgical diagnostics of epilepsy.

High-purified cannabidiol efficacy and safety in a cohort of adult patients with various types of drug-resistant epilepsies

About 30% of patients with epilepsy are drug resistant. Lennox-Gastaut syndrome (LGS), Dravet syndrome (DS) and tuberous sclerosis complex (TSC) are diseases for which high-purified-cannabidiol (CBD) known as Epidiolex® (GW pharma) can be prescribed in add-on of other medications in case of drug-resistance. Currently, there are only a few recent data in the literature about the efficacy and safety of CBD in other forms of refractory epilepsies especially focal epilepsies in adults. We report retrospectively the experience of high-purified-CBD use in two French reference medical centers for epilepsy in various forms of drug-resistant epilepsy. We distinguished two groups of patients: group A with epileptic encephalopathies and group B with focal or multifocal epilepsy. Safety and efficacy (% of responder patients) were evaluated. Finally, 73 patients (51 in group A and 22 in group B) used high-purified CBD as an add-on treatment for their drug-resistant epilepsy. Patients in group A were significantly younger (P=0.0155), with a longer exposition of treatment (P=0.0497) than group B and with higher doses (P=0.0300). Respectively, 15 patients (29.4%) and five patients (22.7%) were responders during the follow-up period (P=0.552). The association with clobazam was more frequent in responders than in non-responder patients (16 patients [80%] versus four [20%]). The most frequent side effect was somnolence. At the end of follow-up, 15 patients in group A (29.4%) and nine patients in group B (40.1%) had stopped the high-purified-CBD treatment due to aggravation of seizure, absence of positive effects, or adverse events. This study showed no significant difference regarding the type of drug-resistant epilepsy and suggests that this treatment may be of interest for all types of drug-resistant epilepsy.

The probability of achieving remission after correction of therapy in patients with pharmacoresistant focal epilepsy

Drug-resistant forms of epilepsy are an important medical and social problem.Goal of the work. Evaluation of the probability of achieving remission after correction of therapy in patients with drug-resistant focal epilepsy.Material and methods. The study included 309 patients divided into three heterogeneous groups: a group of patients with focal pharmacoresistant epilepsy; a group of patients with super refractory focal epilepsy; control group – patients who had not previously received treatment. The examination included history taking, clinical and neurological examination, routine EEG and/or EEG video monitoring, MRI of the brain, and analysis of medical records. Therapy was adjusted.Results. After correction of therapy, remission in patients in Group 1 was achieved in 27.8% of patients, improvement – in 27.1%, no effect – in 45.1%; in Group 2, remission was achieved in 13.2% of patients, improvement – in 28.6%, no effect – in 58.2%; in Group 3, remission was achieved in 41.2% of patients, improvement – in 32.9%, no effect – in 25.9%. Negative prognostic factors did not show a significant correlation with the lack of effect of therapy.Conclusion. After correction of therapy, remission was achieved in several patients with drug-resistant focal epilepsy, while negative prognostic factors do not exclude the possibility of achieving remission.

Ketogenic diet in children and adolescents: The effects on growth and nutritional status

The ketogenic diet is known to be a possible adjuvant treatment in several medical conditions, such as in patients with severe or drug-resistant forms of epilepsy. Its use has recently been increasing among adolescents and young adults due to its supposed weight-loss effect, mediated by lipolysis and lowered insulin levels. However, there are still no precise indications on the possible use of ketogenic diets in pediatric age for weight loss. This approach has also recently been proposed for other types of disorder such as inherited metabolic disorders, Prader-Willi syndrome, and some specific types of cancers. Due to its unbalanced ratio of lipids, carbohydrates and proteins, a clinical evaluation of possible side effects with a strict evaluation of growth and nutritional status is essential in all patients following a long-term restrictive diet such as the ketogenic one. The prophylactic use of micronutrients supplementation should be considered before starting any ketogenic diet. Lastly, while there is sufficient literature on possible short-term side effects of ketogenic diets, their possible long-term impact on growth and nutritional status is not yet fully understood, especially when started in pediatric age.

Characterization of spontaneous seizures and EEG abnormalities in a mouse model of the human A350V IQSEC2 mutation and identification of a possible target for precision medicine based therapy

IQSEC2 is an X-linked gene localized to the post synaptic density encoding a GTP exchange factor that regulates NMDA mediated changes in synaptic function. Mutations in the IQSEC2 gene are associated with drug resistant epilepsy, intellectual disability and autism. Precision medicine based therapeutics to treat IQSEC2 associated epilepsy requires the development and characterization of mutation specific animal models. To date no EEG recordings have been presented for any mouse model of any IQSEC2 mutation showing seizures. In this study we characterize the seizures and EEG brain wave abnormalities present in mice with a A350V IQSEC2 missense mutation that is associated with drug resistant epilepsy in man. We show that seizures are associated with a greater than 40% mortality rate in male mice and occur exclusively from post-natal day 16–20. EEG recordings of mouse pups during this window demonstrate seizures and the presence of spikes with a marked increase in delta waves. EEG recordings in adult male mice have persistent excessive slow frequency activity and spikes, but seizures were not recorded. RNAseq analysis of the hippocampi of mice prior to the development of seizures demonstrated marked abnormalities in canonical pathways involved in synaptogenesis and dendritic maturation with the most prominently dysregulated gene being that for TRH suggesting a potential target for therapy given the previous demonstration of TRH to decrease seizures in several forms of drug resistant epilepsy.

Differential regulation of excitatory synaptic transmission in the hippocampus and anterior temporal lobe by cyclin dependent kinase 5 (Cdk5) in mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS)

Mesial temporal lobe epilepsy with hippocamapal sclerosis (MTLE-HS) is the most common form of drug resistant epilepsy (DRE). MTLE-HS is a distributed network disorder comprising of not only the hippocampus, but other anatomically related extrahippocampal regions. Excitatory synaptic transmission is differentially regulated in the hippocampal and extra-hippocampal regions of patients with MTLE-HS, but its mechanism not understood. Cyclin-dependent kinase 5 (Cdk5) is known to regulate synaptic transmission and plasticity through up-regulation of NMDA receptors by phosphorylating NR2Asubunits. The present study is designed to investigate whether Cdk5 differentially regulates the excitatory synaptic transmission in the hippocampus and anterior temporal lobe (ATL) samples obtained from patients of MTLE-HS. We have measured the Cdk5 kinase activity and the protein levels of Cdk5, p-Cdk5, p35/p25, NR2A, pNR2A in the hippocampal and ATL samples obtained from patients with MTLE-HS. We have also determined the effect of roscovitine, a Cdk5 antagonist, on spontaneous excitatory postsynaptic currents (EPSCs) recorded from the hippocampal and ATL using patch-clamp technique. We observed significant increase in the expression of Cdk5, p-Cdk5, p35/p25, NR2A, pNR2A in the ATL samples as compared to the hippocampal samples. Cdk5 activity was significantly higher in ATL samples as compared to the hippocampal samples. Magnitude of reduction in the frequency of EPSCs by roscovitine in the ATL samples was higher than that in the hippocampal samples. Our studies suggest that Cdk5 differentially regulates excitatory synaptic activity in the hippocampal and ATL region of patients with MTLE-HS.

Modern Problems in the Surgical Treatment of Epilepsy

Background: The surgical treatment of epilepsy is widely recognised by neurosurgeons as the most effective method for treating patients with drug-resistant forms of the disease. Objective: To analyse the results of surgical treatments in patients with epileptic seizures, depending on the applied methods of surgery. Methods: A comprehensive clinical examination of the surgical treatments of 112 patients with various forms of drug-resistant epilepsy was carried out. Results: Hemispherectomy was performed in three patients with positive outcomes. Hippocampectomy was performed for four patients. In two patients, the seizures became medically controlled. In the other two cases, the intervals between seizures were longer and seizures tended to occur at night. Extratemporal resection of the epileptogenic focus was performed in 86 patients, 72% percent of whom became seizure-free. Six patients underwent callosotomy, five of whom were then seizure free. One patient’s seizures resumed after 8 months, this case was also drug-resistant. Thirty two patients underwent multiple subpial transection and were followed-up for approximately 5 years. Excellent results were obtained in 20 (62.5%) patients with seizures ceasing. Conclusions: The results of the study showed sufficient efficiency of the applied methods of surgical treatment for various forms of epilepsy.

Effects of anterior thalamic nuclei stimulation on hippocampal activity: Chronic recording in a patient with drug-resistant focal epilepsy.

Implanted neurostimulation devices are gaining traction as palliative treatment options for certain forms of drug-resistant epilepsy, but clinical utility of these devices is hindered by incomplete mechanistic understanding of their therapeutic effects. Approved devices for anterior thalamic nuclei deep brain stimulation (ANT DBS) are thought to work at a network level, but limited sensing capability precludes characterization of neurophysiological effects outside the thalamus. Here, we describe a patient with drug-resistant temporal lobe epilepsy who was implanted with a responsive neurostimulation device (RNS System), involving hippocampal and ipsilateral temporal neocortical leads, and subsequently received ANT DBS. Over 1.5years, RNS System electrocorticography enabled multiscale characterization of neurophysiological effects of thalamic stimulation. In brain regions sampled by the RNS System, ANT DBS produced acute, phasic, frequency-dependent responses, including suppression of hippocampal low frequency local field potentials. ANT DBS modulated functional connectivity between hippocampus and neocortex. Finally, ANT DBS progressively suppressed hippocampal epileptiform activity in relation to the extent of hippocampal theta suppression, which informs stimulation parameter selection for ANT DBS. Taken together, this unique clinical scenario, involving hippocampal recordings of unprecedented chronicity alongside ANT DBS, sheds light on the therapeutic mechanism of thalamic stimulation and highlights capabilities needed in next-generation devices.

Parental Stress in New-Onset Epilepsy and After Therapy Withdrawal

Objective: To assess maternal and paternal stress inparents of children with epilepsy, at the time of diagnosis, after one year of follow-up and after therapy withdrawal. Methods: We investigated parental stress in a sample of 85 children aged 2-14 years, divided into two groups based on the diagnosis: Group 1 (50 patients) with Childhood Absence Epilepsy or Idiopathic Focal Epilepsy with Rolandic discharges; Group 2 (35 patients) with different forms of drug-resistant Epilepsy. Every parent completed the Parental Stress Index-Short Form at Time 0, when they received the diagnosis and patients started therapy, at Time 1, after 1 year of follow-up. Only parents of Group 1 completed the same questionnaire after 2 years therapy withdrawal. Results: We found high levels of stress in both mothers and fathers at Time 0, without statistically significant differences between the two groups.At Time 1, stress values were unchanged in Group 1 mothers; conversely, the levels of stress in Group 1 fathers were reduced, with average values that fell within the “normal range”. In group 2, stress levels were reduced both in mothers and fathers at Time 1, compared to Time 0, but equally fell into the clinical range, for both parents.In Group1, even one and two years after therapy withdrawal, parental stress did not normalizeand all scores persisted in the “clinical range” in both mothers and fathers. Conclusions: Our study revealed that, the diagnosis of epilepsy itself tended to increase parental stress, apparently regardless of the severity of the disorder; even after a period of follow-up, when epilepsy was better controlled, overall parental stress remained high. Parental stresslevels remained higher than expected, even 2 years after the suspension of therapy and the absence of seizures. This was probably due to concerns with the reappearance of new seizures or a more severe type of epilepsy with the suspension of drug(s), and feelings of inadequacy with their parental role(s).

In humans, sleep spindles are generated by local thalamic pacemakers.

In humans, sleep spindles are generated by local thalamic pacemakers.

Surgery vs no surgery in MRI positive temporal drug resistant forms of epilepsy

Surgery vs no surgery in MRI positive temporal drug resistant forms of epilepsy

Parental stress in a sample of children with epilepsy.

To assess maternal and paternal stress in two groups of children with different types of epilepsy, at the time of diagnosis and after one year of follow-up. We investigated parental stress in a sample of 85 children aged between 2 and 14 years, divided into two groups based on the diagnosis: Group 1 (50 patients) with childhood absence epilepsy or idiopathic focal epilepsy with rolandic discharges and Group 2 (35 patients) with different forms of drug-resistant epilepsy. Parents independently completed the Parental Stress Index-Short Form at Time 0, when they received the diagnosis and patients started therapy, and at Time 1, after 1 year of follow-up. We found high levels of stress in both mothers and fathers at Time 0, without statistically significant differences between the two groups. At Time 1, stress values were unchanged in Group 1 mothers; conversely, the levels of stress in Group 1 fathers reduced, with average values that all fell within the "normal range." In Group 2, stress levels were reduced both in mothers and in fathers at Time 1, compared to Time 0, but equally fell into the "pathological range," for both parents. In our study, the diagnosis of the epilepsy itself tended to increase parental stress, apparently regardless of the severity of the epilepsy; even after a period of follow-up, when the epilepsy was better controlled, overall parental stress remained high. It might have been related to feelings of parental inadequacy or concerns about issues such as safety or the outcome for the child.

Epileptic Seizure Forecasting With Generative Adversarial Networks

Many outstanding studies have reported promising results in seizure forecasting, one of the most challenging predictive data analysis problems. This is mainly because electroencephalogram (EEG) bio-signal intensity is very small, in $\mu \text{V}$ range, and there are significant sensing difficulties given physiological and non-physiological artifacts. Today the process of accurate epileptic seizure identification and data labeling is done by neurologists. The current unpredictability of epileptic seizure activities together with the lack of reliable treatment for patients living with drug resistant forms of epilepsy creates an urgency for research into accurate, sensitive and patient-specific seizure forecasting. Most seizure forecasting algorithms use only labeled data for training purposes. As the seizure data is labeled manually by neurologists, preparing the labeled data is expensive and time consuming, making the best use of the data critical. In this article, we propose an approach that can make use of not only labeled EEG signals but also the unlabeled ones which are more accessible. We use the short-time Fourier transform on 28-s EEG windows as a pre-processing step. A generative adversarial network (GAN) is trained in an unsupervised manner where information of seizure onset is disregarded. The trained Discriminator of the GAN is then used as a feature extractor. Features generated by the feature extractor are classified by two fully-connected layers (can be replaced by any classifier) for the labeled EEG signals. This semi-supervised patient-specific seizure forecasting method achieves an out-of-sample testing area under the operating characteristic curve (AUC) of 77.68%, 75.47% and 65.05% for the CHB-MIT scalp EEG dataset, the Freiburg Hospital intracranial EEG dataset and the EPILEPSIAE dataset, respectively. Unsupervised training without the need for labeling is important because not only it can be performed in real-time during EEG signal recording, but also it does not require feature engineering effort for each patient. To the best of our knowledge, this is the first application of GAN to seizure forecasting.

Structural and functional changes during epileptogenesis in the mouse model of medial temporal lobe epilepsy.

An important issue in epilepsy research is to understand the structural and functional modifications leading to chronic epilepsy, characterized by spontaneous recurrent seizures, after initial brain insult. To address this issue, we recorded and analyzed electroencephalography (EEG) and quantitative magnetic resonance imaging (MRI) data during epileptogenesis in the in vivo mouse model of Medial Temporal Lobe Epilepsy (MTLE, kainate). Besides, this model of epilepsy is a particular form of drug-resistant epilepsy. The results indicate that high-field (4.7T) MRI parameters (T2-weighted; T2-quantitative) allow to detect the gradual neuro-anatomical changes that occur during epileptogenesis while electrophysiological parameters (number and duration of Hippocampal Paroxysmal Discharges) allow to assess the dysfunctional changes through the quantification of epileptiform activity. We found a strong correlation between EEG-based markers (invasive recording) and MRI-based parameters (non-invasive) periodically computed over the `latent period' that spans over two weeks, on average. These results indicated that both structural and functional changes occur in the considered epilepsy model and are considered as biomarkers of the installation of epilepsy. Additionally, such structural and functional changes can also be observed in human temporal lobe epilepsy. Interestingly, MRI imaging parameters could be used to track early (day-7) structural changes (gliosis, cell loss) in the lesioned brain and to quantify the evolution of epileptogenesis after traumatic brain injury.

Z944, a Novel Selective T-Type Calcium Channel Antagonist Delays the Progression of Seizures in the Amygdala Kindling Model.

Temporal lobe epilepsy (TLE) is the most common form of drug resistant epilepsy. Current treatment is symptomatic, suppressing seizures, but has no disease modifying effect on epileptogenesis. We examined the effects of Z944, a potent T-type calcium channel antagonist, as an anti-seizure agent and against the progression of kindling in the amygdala kindling model of TLE. The anti-seizure efficacy of Z944 (5mg/kg, 10mg/kg, 30mg/kg and 100mg/kg) was assessed in fully kindled rats (5 class V seizures) as compared to vehicle, ethosuximide (ETX, 100mg/kg) and carbamazepine (30mg/kg). Each animal received the seven treatments in a randomised manner. Seizure class and duration elicited by six post-drug stimulations was determined. To investigate for effects in delaying the progression of kindling, naive animals received Z944 (30mg/kg), ETX (100mg/kg) or vehicle 30-minutes prior to each kindling stimulation up to a maximum of 30 stimulations, with seizure class and duration recorded after each stimulation. At the completion of drug treatment, CaV3.1, CaV3.2 and CaV3.3 mRNA expression levels were assessed in the hippocampus and amygdala using qPCR. Z944 was not effective at suppressing seizures in fully kindled rats compared to vehicle. Animals receiving Z944 required significantly more stimulations to evoke a class III (p<0.05), IV (p<0.01) or V (p<0.0001) seizure, and to reach a fully kindled state (p<0.01), than animals receiving vehicle. There was no significant difference in the mRNA expression of the T-type Ca2+ channels in the hippocampus or amygdala. Our results show that selectively targeting T-type Ca2+ channels with Z944 inhibits the progression of amygdala kindling. This could be a potential for a new therapeutic intervention to mitigate the development and progression of epilepsy.

Drug-resistant epilepsy associated with cortical dysplasias

Epilepsy associated with malformations of the cerebral cortex is reported in the literature to account for up to 25% of the total cases of symptomatic epilepsies. It is characterized by the most severe course and often induces drug-resistance in seizures. A group of patients with resistant seizures is singled out among the total number of patients with symptomatic epilepsy caused by cerebral cortical dysgenesis. The most important risk factors for resistance are identified in dysplasias. The prognostically unfavorable clinical features of epilepsy are described. A diagnostic algorithm is proposed to identify risk groups and to prevent drug-resistant forms of epilepsy.