mTOR-therapy and targeted treatment opportunities in mTOR-related epilepsies associated with cortical malformations

Dysregulation of the mTOR pathway is now well documented in several neurodevelopmental disorders associated with epilepsy. Mutations of mTOR pathway genes are involved in tuberous sclerosis complex (TSC) as well as in a range of cortical malformations from hemimegalencephaly (HME) to type II focal cortical dysplasia (FCD II), leading to the concept of "mTORopathies" (mTOR pathway-related malformations). This suggests that mTOR inhibitors (notably rapamycin (sirolimus), and everolimus) could be used as antiseizure medication. In this review, we provide an overview of pharmacological treatments targeting the mTOR pathway for epilepsy based on lectures from the ILAE French Chapter meeting in October 2022 in Grenoble. There is strong preclinical evidence for the antiseizure effects of mTOR inhibitors in TSC and cortical malformation mouse models. There are also open studies on the antiseizure effects of mTOR inhibitors, as well as one phase III study showing the antiseizure effect of everolimus in TSC patients. Finally, we discuss to which extent mTOR inhibitors might have properties beyond the antiseizure effect on associated neuropsychiatric comorbidities. We also discuss a new way of treatment on the mTOR pathways.

A companion to the preclinical common data elements for rodent genetic epilepsy models. A report of the TASK3-WG1B: Paediatric and genetic models working group of the ILAE/AES joint translational TASK force

Rodent models of epilepsy remain the cornerstone of research into the mechanisms underlying genetic epilepsy. Reproducibility of experiments using these rodent models, occurring across a diversity of laboratories and commercial vendors, remains an issue impacting the cost-effectiveness and scientific rigor of the studies performed. Here, we present two case report forms (CRFs) describing common data elements (CDE) for genetic rodent models, developed by the TASK3-WG1B Working Group of the International League Against Epilepsy (ILAE)/American Epilepsy Society (AES) Joint Translational Task Force. The first CRF relates to genetic rodent models that have been engineered based on variants described in epilepsy patients. The second CRF encompasses both spontaneous and inbred rodent models. This companion piece describes the elements and discusses the important factors to consider before documenting each required element. These CRFs provide tools that allow investigators to more uniformly describe core experimental data on different genetic models across laboratories, with the aim of improving experimental reproducibility and thus translational impact of such studies.

A simple novel approach for detecting blood-brain barrier permeability using GPCR internalization

Aims

Impairment of blood–brain barrier (BBB) is involved in numerous neurological diseases from developmental to aging stages. Reliable imaging of increased BBB permeability is therefore crucial for basic research and preclinical studies. Today, the analysis of extravasation of exogenous dyes is the principal method to study BBB leakage. However, these procedures are challenging to apply in pups and embryos and may appear difficult to interpret. Here we introduce a novel approach based on agonist‐induced internalization of a neuronal G protein‐coupled receptor widely distributed in the mammalian brain, the somatostatin receptor type 2 (SST2).

Methods

The clinically approved SST2 agonist octreotide (1 kDa), when injected intraperitoneally does not cross an intact BBB. At sites of BBB permeability, however, OCT extravasates and induces SST2 internalization from the neuronal membrane into perinuclear compartments. This allows an unambiguous localization of increased BBB permeability by classical immunohistochemical procedures using specific antibodies against the receptor.

Results

We first validated our approach in sensory circumventricular organs which display permissive vascular permeability. Through SST2 internalization, we next monitored BBB opening induced by magnetic resonance imaging‐guided focused ultrasound in murine cerebral cortex. Finally, we proved that after intraperitoneal agonist injection in pregnant mice, SST2 receptor internalization permits analysis of BBB integrity in embryos during brain development.

Conclusions

This approach provides an alternative and simple manner to assess BBB dysfunction and development in different physiological and pathological conditions.

Recommandations Formalisées d’Experts SRLF/SFMU : Prise en charge des états de mal épileptiques en préhospitalier, en structure d’urgence et en réanimation dans les 48 premières heures (A l’exclusion du nouveau-né et du nourrisson)

La Société de réanimation de langue française et la Société française de médecine d’urgence ont décidé d’élaborer de nouvelles recommandations sur la prise en charge de l’état mal épileptique (EME) avec l’ambition de répondre le plus possible aux nombreuses questions pratiques que soulèvent les EME : diagnostic, enquête étiologique, traitement non spécifique et spécifique. Vingt-cinq experts ont analysé la littérature scientifique et formulé des recommandations selon la méthodologie GRADE. Les experts se sont accordés sur 96 recommandations. Les recommandations avec le niveau de preuve le plus fort ne concernent que l’EME tonico-clonique généralisé (EMTCG) : l’usage des benzodiazépines en première ligne (clonazépam en intraveineux direct ou midazolam en intramusculaire) est recommandé, répété 5 min après la première injection (à l’exception du midazolam) en cas de persistance clinique. En cas de persistance 5 min après cette seconde injection, il est proposé d’administrer la seconde ligne thérapeutique : valproate de sodium, (fos-)phénytoïne, phénobarbital ou lévétiracétam. La persistance avérée de convulsions 30 min après le début de l’administration du traitement de deuxième ligne signe l’EMETCG réfractaire. Il est alors proposé de recourir à un coma thérapeutique au moyen d’un agent anesthésique intraveineux de type midazolam ou propofol. Des recommandations spécifiques à l’enfant et aux autres EME sont aussi énoncées.

[Therapeutic management of neonatal arterial cerebral infarction and neuroprotection perspectives]

Neonatal seizure related to stroke is a common diagnostic feature. Their treatment, although widely debated even today must be initiated in case of status epilepticus, clinical seizures of more than 5 minutes duration or short (> 30 secondes) and repeated clinical seizures (2 or more per hour). The treatment of neonatal seizures is a challenge that remains only partially solved. It should take into account the etiology of seizures, type of brain lesions and clinical/electrical response to treatment after the first line treatment. It is based on using a single anti-epileptic at its maximum dosage, and if needed, on the association with another anti-epileptic drug with a different mechanism of action. Phenobarbital remains the most commonly used drug for initial treatment of neonatal seizures and for which the most clinical experience has been accumulated. The lack of randomized controlled trials makes difficult recommendations about the optimal duration of treatment, but most experts agree that once arrested seizures, the duration of treatment should be as short as possible because of its potential risk on the developing brain. Novel neuroprotective strategies for reducing impact of neonatal stroke or promoting brain repair remain for the moment the concept stage, pre-clinical or parcel clinical data.

Retrospective evaluation of low long-term efficacy of antiepileptic drugs and ketogenic diet in 39 patients with CDKL5-related epilepsy

OBJECTIVE

Mutations in the CDKL5 gene cause an early-onset epileptic encephalopathy. To date, little is known about effective antiepileptic treatment in this disorder.

METHOD

Accordingly, the aim of this retrospective study was to explore the role of different antiepileptic drugs (AEDs) and the ketogenic diet (KD) in the treatment of this rare genetic disorder. We evaluated the efficacy in 39 patients with CDKL5 mutations at 3, 6 and 12 months after the introduction of each treatment. One patient was lost to follow-up after 6 and 12 months.

RESULTS

The responder rate (>50% reduction in seizure frequency) to at least one AED or KD was 69% (27/39) after 3 months, 45% (17/38) after 6 months and 24% (9/38) after 12 months. The highest rate of seizure reduction after 3 months was reported for FBM (3/3), VGB (8/25), CLB (4/17), VPA (7/34), steroids (5/26), LTG (5/23) and ZNS (2/11). Twelve patients (31%) experienced a seizure aggravation to at least one AED. Most patients showed some but only initial response to various AEDs with different modes of actions.

SIGNIFICANCE

Considering both age-related and spontaneous fluctuation in seizure frequency and the unknown impact of many AEDs or KD on cognition, our data may help defining realistic treatment goals and avoiding overtreatment in patients with CDKL5 mutations. There is a strong need to develop new treatment strategies for patients with this rare mutation.

[Assessment of education needs of adolescents and parents of children with epilepsy]

INTRODUCTION

Education program for patients (EPP) is now a part of the management of patients with chronic disease. According to WHO, the EPP is designed to help patients to maintain or gain self-care skills and adaptive skills necessary to improve their health and their quality of life. Patient education programs have been developed in recent years in several chronic diseases such as diabetes and asthma. In the field of epilepsy, however, adult and child programs have been developed only recently in France. We evaluate the interests for the establishment of an EPP and the topics that the parents and the adolescents would like to be discussed in such courses.

METHODS

We conducted a qualitative survey, based on interviews of parents of epileptic children and adolescents. The survey was conducted between April and November 2010 in pediatric neurology services of four French university hospitals: Amiens, Nancy, Marseille, and in Robert Debré (Paris) hospital. We investigated the following issues: treatment and self-management, and seizure management, psychosocial difficulties related to epilepsy, anatomical and physiological knowledge of epilepsy and lifestyle.

RESULTS

Two topics seem to have the greatest interest for parents of children with epilepsy and adolescents: knowledge about seizures and knowledge of anatomy and physiology of the brain. Adolescents involved in this study gave consistently lower scores in all items compare to parents of children.

CONCLUSION

The medical management of children and adolescents with epilepsy, and their caregivers, is a comprehensive care including the EPP in order to provide a full management of all issues raised by epilepsy. The survey identified key-points that parents and their children would like to learn in an EPP. These data would be helpful to design an EPP.

[Use of injectable lorazepam in status epilepticus: a comparative study in French-speaking hospitals]

BACKGROUND

Injectable lorazepam (IL) is marketed in many countries but in France is only available within the framework of a compassionate use program for refractory status epilepticus. This study aims to evaluate the differences of pediatric use and status of IL in the hospitals of the Mother-Child French-speaking Network (Réseau mère-enfant de la francophonie, i.e., RMEF).

METHODS

Inclusion criteria are: firstly, RMEF member; secondly, one site per town; thirdly, all the Assistance publique-Hôpitaux de Paris hospitals. After a phone-recruitment in each selected hospital, a survey was sent by e-mail. The data collected concerned the number of beds in the hospital, the official status of IL, its place in the therapeutic strategy, in hospital consumption in 2008 (in milligram) and the therapeutic alternatives.

RESULTS

Among the 18 hospitals selected, 17 were contacted and 12 (70%) replied. IL is not marketed in Tunisia and Lebanon. In Switzerland, Canada and Belgium, IL is marketed and used in all the polled hospitals (6.2 to 48.0mg per bed). In France, only the Robert Debré Hospital uses it (3.2mg per bed). In the countries where it is marketed, IL was firstly prescribed for the studied indication. In the other countries, injectable diazepam was the first line treatment (six out of eight hospitals).

DISCUSSION/CONCLUSION

France is the only country where IL is available though not marketed. The pharmacokinetic data favor use of IL instead of its principal therapeutic alternative (injectable diazepam) but no currently available evidence concludes that IL is superior to diazepam in the management of pediatric status epilepticus. The official indication of IL in France (last intention) is in contradiction with its use in the countries where it is marketed and with the data of the literature in favor of the first intention. This works presents the first evaluation on the use of IL in pediatric status epilepticus in the RMEF hospitals. It highlights the discrepancies in the management of status epilepticus in comparable pediatric hospitals.

MEF2C haploinsufficiency caused by either microdeletion of the 5q14.3 region or mutation is responsible for severe mental retardation with stereotypic movements, epilepsy and/or cerebral malformations

BACKGROUND

Over the last few years, array-comparative genomic hybridisation (CGH) has considerably improved our ability to detect cryptic unbalanced rearrangements in patients with syndromic mental retardation.

METHOD

Molecular karyotyping of six patients with syndromic mental retardation was carried out using whole-genome oligonucleotide array-CGH.

RESULTS

5q14.3 microdeletions ranging from 216 kb to 8.8 Mb were detected in five unrelated patients with the following phenotypic similarities: severe mental retardation with absent speech, hypotonia and stereotypic movements. Facial dysmorphic features, epilepsy and/or cerebral malformations were also present in most of these patients. The minimal common deleted region of these 5q14 microdeletions encompassed only MEF2C, the gene for a protein known to act in brain as a neurogenesis effector, which regulates excitatory synapse number. In a patient with a similar phenotype, an MEF2C nonsense mutation was subsequently identified.

CONCLUSION

Taken together, these results strongly suggest that haploinsufficiency of MEF2C is responsible for severe mental retardation with stereotypic movements, seizures and/or cerebral malformations.

[Management of the first nonfebrile seizure in infants and children]

Seizures are the most common pediatric neurologic disorder. This article describes the guidelines of the French Pediatric Neurology Society, highlighting the importance of a thorough history and examination. Paroxysmal nonepileptic events should be excluded. The role of biological and neuroradiological investigations is discussed. An electroencephalographic recording and advice from a pediatric neurologist are suggested.

[Interest of the ketogenic diet in a refractory status epilepticus in adults]

INTRODUCTION

Ketogenic diets have been employed for the treatment of intractable epilepsy in children since 1921, although underlying mechanism remains unknown.

OBSERVATION

We report the case of a 54-year-old man with partial refractory status epilepticus who exhibited a favourable outcome about seven days after introduction of a ketogenic diet in association with antiepileptic drugs.

DISCUSSION

Although its efficiency was largely demonstrated in children, little is known about the impact of a ketogenic diet in adults with refractory epilepsy.

CONCLUSION

Introduction of a ketogenic diet requires a multidisciplinary approach. Its usefulness in adult intractable epilepsy and/or refractory status epilepticus merits further study into its efficacy in reducing the frequency of seizures and a possible prolonged effect.

Inflammation contributes to seizure-induced hippocampal injury in the neonatal rat brain

OBJECTIVE

The extent of neuronal injury in the hippocampus produced by experimental status epilepticus (SE) is age dependent and is not readily demonstrable in many models of neonatal seizures. Neonatal seizures often occur in clinical settings that include an inflammatory component. We examined the potential contributory role of pre-existing inflammation as an important variable in mediating neuronal injury.

MATERIALS AND METHODS

Postnatal day 7 (P7) and P14 rat pups were injected with lipopolysaccharide (LPS), 2 h prior to SE induced by lithium-pilocarpine (LiPC). Neuronal injury was assessed by well-described histologic methods.

RESULTS

While LPS by itself did not produce any discernible cell injury at either age, this treatment exacerbated hippocampal damage induced by LiPC-SE. The effect was highly selective for the CA1 subfield.

CONCLUSIONS

Inflammation can contribute substantially to the vulnerability of immature hippocampus to seizure-induced neuronal injury. The combined effects of inflammation and prolonged seizures in early life may impact long-term outcomes of neonatal seizures.

Varicelle en bracelet: illustration des éruptions varicelleuses atypiques

We report on a 3-year-old child with bracelet localisation of chickenpox. Varicella with unusual clinical aspects and course is known as atypical varicella; it is characterized by its unique clinical features, unusual distribution, or a prolonged course. In case of atypical varicella, clinical diagnosis can be difficult. Pre-existing factors have been reported such as immunocompromised status, sun exposition, local injury and pre-existing rash.

Inflammation contributes to seizure-induced hippocampal injury in the neonatal rat brain

OBJECTIVE

The extent of neuronal injury in the hippocampus produced by experimental status epilepticus (SE) is age dependent and is not readily demonstrable in many models of neonatal seizures. Neonatal seizures often occur in clinical settings that include an inflammatory component. We examined the potential contributory role of pre-existing inflammation as an important variable in mediating neuronal injury.

MATERIALS AND METHODS

Postnatal day 7 (P7) and P14 rat pups were injected with lipopolysaccharide (LPS), 2 h prior to SE induced by lithium-pilocarpine (LiPC). Neuronal injury was assessed by well-described histologic methods.

RESULTS

While LPS by itself did not produce any discernible cell injury at either age, this treatment exacerbated hippocampal damage induced by LiPC-SE. The effect was highly selective for the CA1 subfield.

CONCLUSIONS

Inflammation can contribute substantially to the vulnerability of immature hippocampus to seizure-induced neuronal injury. The combined effects of inflammation and prolonged seizures in early life may impact long-term outcomes of neonatal seizures.

Small vessel abnormalities in alternating hemiplegia of childhood: Pathophysiologic implications

BACKGROUND

The pathophysiology of alternating hemiplegia of childhood (AHC) is unclear. The authors evaluated the skin and muscle biopsies from patients with AHC for vascular abnormalities.

METHODS

Skin biopsy specimens from four patients ages 18 months, 8 years, 9 years, and 18 years and muscle biopsies from two of these patients were examined by electron microscopy and compared with healthy controls.

RESULTS

Vascular abnormalities were found in both skin and muscle. Skin biopsies showed similar abnormalities in all four patients. Vacuoles were visible in the endothelium. The most striking abnormality was the presence in the tunica media of small and unevenly shaped vascular smooth muscle cells (VSMCs) containing intracytoplasmic vacuoles and, occasionally, apoptotic nuclei, with variations according to patient age. Moreover, most VSMCs had lost junctions with neighboring cells, and some were completely isolated. In vessels from muscle biopsies, the VSMCs showed vacuoles, residual osmiophilic deposits, and myofilament loss with substitution by vacuoles.

CONCLUSIONS

The vascular abnormalities in our patients suggest a primary or secondary vascular pathophysiology to alternating hemiplegia of childhood. The vascular smooth muscle cells may be the initial target of the disease process.

[Neuropediatric approach to autism]

Autism is defined by 3 main criteria: disturbance of reciprocal social interaction, disturbance of communication (including language comprehension and spoken language) and disturbance of normal variation in behaviour and imaginative activities; an onset before age 36 months is also required. The neuropediatric contribution to autism is dominated by the search for an underlying organic etiology, especially if there are arguments for an associated encephalopathy: ante- or perinatal medical history, dysmorphic signs, skin spots, neurological abnormalities, somatic abnormalities compatible with a neurometabolic disorder. The main associated conditions with autism are: chromosome anomalies, monogenic syndrome (including fragile X syndrome), neurocutaneous syndromes, epileptic encephalopathies, neurometabolic diseases, and dystrophinopathies. The identification of an associated medical condition to autism is primordial in prospect of genetic counselling, and by the change induced in familial perception of autism.

Traitement médicamenteux de l’accès migraineux chez l’enfant

Migraine, according to the criteria of the International Headache Society, occurs in about 5 to 10% of children. Management of acute headache is only one of the parts of the treatment, along with identification of migraine precipitants, adjustments in lifestyle, and when necessary the use of preventive therapy, which can include non pharmacologic (relaxation or biofeedback) or pharmacologic treatment. In the acute migraine attack, a single dose of either ibuprofen 10 mg/kg or paracetamol 15 mg/kg has been shown to be effective, with only a few adverse effects. In severe migraine attacks, dihydroergotamine mesylate administered orally (20 to 40 microg/kg) or intravenously (maximum 1 mg/day) may be helpful, but there have been no large placebo-controlled trials of this treatment. Among the different triptans, it is the sumatriptan nasal spray whose efficacy has been best demonstrated. The most frequent adverse event is transitory unpleasant taste.

Traitement de fond de la migraine de l’enfant : état des connaissances du traitement pharmacologique

Migraine, according to the criteria of the International Headache Society, occurs in about 5-10% of children. Preventive therapy includes identification of migraine precipitants, possible adjustments in lifestyle, appropriate management of acute headache, and when necessary the use of pharmacologic agents. It should be started if migraine attacks are severe or frequent. Non-pharmacologic prophylactic treatment is the modality of choice, based on relaxation or biofeedback. Despite its high incidence, only a few controlled trials have investigated the prophylactic treatment of migraine in children. Only flunarizine (5 mg/day) has been shown to be effective in two double-blind, placebo-controlled trials. Some evidence also exists that propranolol (60 mg/day) and pizotifen (0.5-1.5 mg/day) are effective. For all other drugs studied in migraine prophylaxis, the results remain vague (e.g. amitriptyline), or suggest inefficacy (e.g. clonidine, tryptophane). Most of the drugs used in the treatment of migraine in children are well tolerated. The most common adverse effects are drowsiness and bodyweight gain.

BN 80933, a dual inhibitor of neuronal nitric oxide synthase and lipid peroxidation: a promising neuroprotective strategy

Nitric oxide (NO) and reactive oxygen species (ROS) act independently as well as cooperatively to induce neuronal death in acute neurological disorders. Inhibition of neuronal nitric oxide synthase (nNOS) and inhibition of lipid peroxidation induced by ROS have both been proposed as neuroprotective strategies in stroke and trauma. Recently, in our laboratory, the combination of the two strategies was found to be synergistic in reducing neuronal damage. Here, we report that BN 80933 [(S)-N-[4-[4-[(3,4-dihydro-6-hydroxy-2, 5,7, 8-tetramethyl-2H-1-benzopyran-2-yl)carbonyl]-1-piperazinyl]phenyl]-2- thiophenecarboximidamide], a compound that combines potent antioxidant and selective nNOS inhibitory properties in vitro, affords remarkable neuronal protection in vivo. Intravenous administration of BN 80933 significantly reduced brain damage induced by head trauma in mice, global ischemia in gerbils, and transient focal ischemia in rats. Treatment with BN 80933 (0.3-10 mg/kg) significantly reduced infarct volume (>60% protection) and enhanced behavioral recovery in rats subjected to transient (2-h) middle cerebral artery occlusion and 48-h or 7-day reperfusion. Furthermore, treatment with BN 80933 commencing up to 8 h after the onset of ischemia resulted in a significant improvement of neurological outcome. All these results indicate that BN 80933 represents a class of potentially useful therapeutic agents for the treatment of stroke or trauma and possibly neurodegenerative disorders that involve both NO and ROS.