Temporal lobe epilepsy in children

Low-grade glioma of the temporal lobe and tumor-related epilepsy in children

PURPOSE

Low-grade glioma is the most common brain tumor among children and adolescents. When these tumors arise in the temporal lobe, patients frequently present with seizures that are poorly controlled with antiepileptic drugs. Here we summarize the clinical features, pathophysiology, preoperative evaluation, surgical treatment, and outcomes of pediatric patients with low-grade gliomas in the temporal lobe.

METHODS

We reviewed the literature on pediatric low-grade gliomas in the temporal lobe, focusing on cohort studies and systematic reviews that described surgical treatment strategies and reported both oncologic and epilepsy outcomes.

RESULTS

The differential diagnoses of pediatric low-grade gliomas in the temporal lobe include ganglioglioma, dysembryoplastic neuroepithelial tumor, desmoplastic infantile ganglioglioma, papillary glioneuronal tumor, pilocytic astrocytoma, pleomorphic xanthoastrocytoma, angiocentric glioma, and polymorphous low-grade neuroepithelial tumor of the young. There is no consensus on the optimal surgical approach for these tumors: lesionectomy alone, or extended lesionectomy with anterior temporal lobectomy, with or without removal of mesial temporal structures. Gross total resection and shorter preoperative duration of epilepsy are strongly associated with favorable seizure outcomes, defined as Engel Class I or Class II, approaching 90% in most series. The risk of surgical complications ranges from 4 to 17%, outweighing the lifetime risks of medically refractory epilepsy.

CONCLUSION

Pediatric patients with temporal low-grade glioma and tumor-related epilepsy are best managed by a multidisciplinary epilepsy surgery team. Early and appropriate surgery leads to prolonged survival and a greater likelihood of seizure freedom, improving their overall quality of life.

Epilepsy: Mitochondrial connections to the 'Sacred' disease

Over 65 million people suffer from recurrent, unprovoked seizures. The lack of validated biomarkers specific for myriad forms of epilepsy makes diagnosis challenging. Diagnosis and monitoring of childhood epilepsy add to the need for non-invasive biomarkers, especially when evaluating antiseizure medications. Although underlying mechanisms of epileptogenesis are not fully understood, evidence for mitochondrial involvement is substantial. Seizures affect 35%-60% of patients diagnosed with mitochondrial diseases. Mitochondrial dysfunction is pathophysiological in various epilepsies, including those of non-mitochondrial origin. Decreased ATP production caused by malfunctioning brain cell mitochondria leads to altered neuronal bioenergetics, metabolism and neurological complications, including seizures. Iron-dependent lipid peroxidation initiates ferroptosis, a cell death pathway that aligns with altered mitochondrial bioenergetics, metabolism and morphology found in neurodegenerative diseases (NDDs). Studies in mouse genetic models with seizure phenotypes where the function of an essential selenoprotein (GPX4) is targeted suggest roles for ferroptosis in epilepsy. GPX4 is pivotal in NDDs, where selenium protects interneurons from ferroptosis. Selenium is an essential central nervous system micronutrient and trace element. Low serum concentrations of selenium and other trace elements and minerals, including iron, are noted in diagnosing childhood epilepsy. Selenium supplements alleviate intractable seizures in children with reduced GPX activity. Copper and cuproptosis, like iron and ferroptosis, link to mitochondria and NDDs. Connecting these mechanistic pathways to selenoproteins provides new insights into treating seizures, pointing to using medicines including prodrugs of lipoic acid to treat epilepsy and to potential alternative therapeutic approaches including transcranial magnetic stimulation (transcranial), photobiomodulation and vagus nerve stimulation.

Expression Profile of miRs in Mesial Temporal Lobe Epilepsy: Systematic Review

Temporal lobe epilepsy (TLE) is one of the most common forms of focal epilepsy in children and adults. TLE is characterized by variable onset and seizures. Moreover, this form of epilepsy is often resistant to pharmacotherapy. The search for new mechanisms for the development of TLE may provide us with a key to the development of new diagnostic methods and a personalized approach to the treatment. In recent years, the role of non-coding ribonucleic acids (RNA) has been actively studied, among which microRNA (miR) is of the greatest interest. (1) Background: The purpose of the systematic review is to analyze the studies carried out on the role of miRs in the development of mesial TLE (mTLE) and update the existing knowledge about the biomarkers of this disease. (2) Methods: The search for publications was carried out in the databases PubMed, Springer, Web of Science, Clinicalkeys, Scopus, OxfordPress, Cochrane. The search was carried out using keywords and combinations. We analyzed publications for 2016–2021, including original studies in an animal model of TLE and with the participation of patients with TLE, thematic and systemic reviews, and Cochrane reviews. (3) Results: this thematic review showed that miR‒155, miR‒153, miR‒361‒5p, miR‒4668‒5p, miR‒8071, miR‒197‒5p, miR‒145, miR‒181, miR‒199a, miR‒1183, miR‒129‒2‒3p, miR‒143‒3p (upregulation), miR–134, miR‒0067835, and miR‒153 (downregulation) can be considered as biomarkers of mTLE. However, the roles of miR‒146a, miR‒142, miR‒106b, and miR‒223 are questionable and need further study. (4) Conclusion: In the future, it will be possible to consider previously studied miRs, which have high specificity and sensitivity in mTLE, as prognostic biomarkers (predictors) of the risk of developing this disease in patients with potentially epileptogenic structural damage to the mesial regions of the temporal lobe of the brain (congenital disorders of the neuronal migration and neurogenesis, brain injury, neuro-inflammation, tumor, impaired blood supply, neurodegeneration, etc.).

Chronic pediatric diseases and risk for reading difficulties: a narrative review with recommendations

Literacy is a major social determinant of health, rooted in skills that develop during early childhood. Children arriving at kindergarten unprepared to learn to read are more likely to have low reading proficiency thereafter. General and health literacy are highly correlated, affecting understanding of health conditions, treatment adherence, and transition to self-care and adult healthcare services. The American Academy of Pediatrics (AAP) recommends literacy and school readiness promotion during well-visits and neurodevelopmental surveillance is emphasized across primary and subspecialty care. While genetic and environmental risk factors for reading difficulties are well-established, risks related to complex and chronic medical conditions are less appreciated and under-researched. This review applies an eco-bio-developmental framework to explore literacy across five complex chronic conditions affecting millions of children worldwide: asthma, cancer, congenital heart disease, epilepsy, and sickle cell disease. In each, integration of an efficient reading brain network may be impacted by direct factors, such as ischemia, anesthesia, and/or medications, and also indirect factors, such as altered parent-child routines, hospital stays, and missed school. By integrating literacy into care management plans for affected children, pediatric primary care and specialty providers are poised to identify risks early, target guidance and interventions, and improve academic and health outcomes. IMPACT: While genetic and environmental risk factors for reading difficulties are well-established, risks related to complex and/or chronic medical conditions such as asthma, cancer, congenital heart disease, epilepsy, and sickle cell disease are substantial, less appreciated, and under-researched. General and health literacy are highly correlated, with implications for the understanding one's health condition, treatment adherence, and transitioning to self-care, which is especially important for children with complex and/or chronic illness. Pediatric primary care and specialty providers are poised to integrate reading and literacy into care management plans for children with complex and/or chronic illness, including early screening, guidance, support, and interventions.

Gastrodin attenuates lithium-pilocarpine-induced epilepsy by activating AMPK-mediated PPARα in a juvenile rat model

Gastrodin has shown the potential as an anticonvulsant. Epilepsy is a neurological disease with significant effects in children. In the current study, the therapeutic potential of gastrodin in handling pediatric epilepsy was explored by focusing on the AMPK/PPARα pathway. Three-week-old Sprague-Dawley rats were subjected to lithium-pilocarpine method to induce epileptic symptoms and then administrated with gastrodin. The effects of gastrodin on rats were first assessed using electroencephalogram (EEG) recording, Racine classification, Morris water maze test, and histological staining. The levels of BDNF and NGF, and the activity of AMPK/PPARα were measured. Based on the results of EEG, behavior analyses, and histological staining, epileptic symptoms were significantly alleviated by gastrodin. Moreover, the administration of gastrodin also suppressed the levels of BDNF and NGF, and activated the AMPK/PPARα pathway. In conclusion, our results demonstrated that gastrodin contributed to the alleviation of pediatric epilepsy by activating AMPK/PPARα signaling transduction.

Prospects and Limitations Related to the Use of MicroRNA as a Biomarker of Epilepsy in Children: A Systematic Review

Epilepsy is one of the most common neurological diseases in children. There is an unmet need for new objective methods that would facilitate and accelerate the diagnostic process, thus improving the prognosis. In many studies, the participation of microRNA in epileptogenesis has been confirmed. Therefore, it seems to be a promising candidate for this role. Scientists show the possibility of using microRNAs as diagnostic and predictive biomarkers as well as novel therapeutic targets. Children with epilepsy would benefit particularly from the use of this innovative method. However, the number of studies related to this age group is very limited. This review is based on 10 studies in children and summarizes the information collected from studies on animal models and the adult population. A total of 136 manuscripts were included in the analysis. The aim of the review was to facilitate the design of studies in children and to draw attention to the challenges and traps related to the analysis of the results. Our review suggests a high potential for the use of microRNAs and the need for further research.

Inhibition of miR-181a-5p reduces astrocyte and microglia activation and oxidative stress by activating SIRT1 in immature rats with epilepsy

MicroRNAs regulate gene expression at the posttranscriptional level, and this process has been shown to be implicated in the pathological processes of temporal lobe epilepsy. At present, studies about the impact of microRNA-181a (miR-181a) on epilepsy have focused on hippocampal neurons, and the effect of miR-181a on other cells in the hippocampus remains poorly understood. Herein, we explored the role of miR-181a-5p in a lithium-pilocarpine model of epilepticus in immature rats. We found that the hippocampal expression level of miR-181a-5p was increased. Inhibition of miR-181a-5p protected the hippocampus against epilepsy, including hippocampal insults, neuronal apoptosis, astrocyte and microglia activation, neuroinflammation, oxidative stress, mitochondrial function, and cognitive dysfunction. Moreover, miR-181a-5p inhibition exerted a seizure-suppressing effect via SIRT1 upregulation. Overall, our findings reveal the potential role of the miR-181a-5p/SIRT1 pathway in the development of temporal lobe epilepsy, and this pathway may represent a novel target for ameliorating epilepsy and its sequelae.

Epilepsy surgery in children: what the radiologist needs to know

This review updates the radiologist on current epilepsy surgery practice in children, with a specific focus on the role of imaging in pre-surgical work-up, current and novel surgical techniques, expected post-surgical imaging appearances and important post-operative complications. A comprehensive review of the current and emerging international practices in paediatric epilepsy surgical planning and post-operative imaging is provided with details on case-based radiological findings. A detailed discussion of the pathophysiology and imaging features of different epileptogenic lesions will not be discussed as this is not the objective of this paper. Epilepsy surgery can be an effective method to control seizures in certain children with drug-resistant focal epilepsy. Early surgery in selected appropriate cases can lead to improved cognitive and developmental outcome. Advances in neurosurgical techniques, imaging and neuroanaesthesia have driven a parallel expansion in the array of epilepsy conditions which are potentially treatable with surgery. The range of surgical options is now wide, including minimally invasive ablative procedures for small lesions such as hypothalamic hamartomata, resections for focal lesions like hippocampal sclerosis and complex disconnective surgeries for multilobar conditions like Sturge Weber Syndrome and diffuse cortical malformations. An awareness of the surgical thinking when planning epilepsy surgery in children, and the practical knowledge of the operative steps involved will promote more accurate radiology reporting of the post-operative scan.

MicroRNA-15a-5p serves as a potential biomarker and regulates the viability and apoptosis of hippocampus neuron in children with temporal lobe epilepsy

BACKGROUND

Temporal lobe epilepsy (TLE) is the most common type of epilepsy, usually starting in childhood. The dysregulation of microRNAs (miRNAs) has been identified in neurological disorders. The current study investigated the expression level and clinical significance of miR-15a-5p in TLE children, and explored its function in regulating cell behaviors of hippocampal neurons.

METHODS

The expression level of miR-15a-5p was examined in the serum of 63 TLE children. Primary hippocampal cells were cultured in magnesium-free medium to mimic TLE condition in children. The effect of miR-15a-5p on the viability and apoptosis of hippocampus neuron was assessed using MTT or flow cytometric apoptosis assay.

RESULTS

TLE children had significantly low expression of miR-15a-5p. MiR-15a-5p was of great value for the diagnosis of TLE in children, with high specificity and sensitivity. The expression level of miR-15a-5p was decreased significantly in hippocampal cells treated in the magnesium-free medium. Overexpression of miR-15a-5p attenuated TLE-induced reduction for cell viability, and reversed the cell apoptosis induced by TLE.

CONCLUSIONS

MiR-15a-5p is downregulated in children with TLE, and overexpression of miR-15a-5p promoted the viability and inhibited the apoptosis of hippocampal neuron. MiR-15a-5p may be a promising biomarker for the diagnosis of children TLE.

Noninvasive identification of seizure lateralization in children: Name that thing

OBJECTIVE

With this prospective, observational study, we aimed to determine whether noninvasive language tasks, developed specifically for children, could reliably identify the hemisphere of seizure onset in pediatric epilepsy.

METHODS

Seventy-eight children with unilateral epilepsy (44 left), aged 6-15 years (mean age = 11.8, SD = 2.6), completed the Children's Auditory Naming and Visual Naming Tests, the Boston Naming Test, and other verbal and nonverbal tasks. Multivariate analysis of variance was used to compare test performance between left and right hemisphere epilepsy groups, and χ2 analyses and odds ratios were used to examine classification of left vs right hemisphere epilepsy for individual patients based on test performance.

RESULTS

Group comparisons revealed poorer auditory naming in children with left hemisphere epilepsy (p = 0.02), yet no significant differences on measures of visual naming, general intelligence, or other cognitive functions. Moreover, χ2 analyses using auditory naming cutoff scores to define intact vs impaired performance correctly classified seizure laterality in a significant proportion of children (p = 0.004). The odds of left hemisphere epilepsy were 4.2 times higher (95% confidence interval 1.4-11.7) than the odds of right hemisphere epilepsy with poor auditory naming performance. In the subset of patients with temporal lobe epilepsy (TLE), the odds of left TLE were 11.3 times higher (95% confidence interval 2.00-63.17) than the odds of right TLE with poor auditory naming performance.

CONCLUSION

Contrary to previous findings, naming performance can lateralize hemisphere of seizure onset in children with epilepsy, thereby assisting in the preoperative workup for pediatric epilepsy surgery.

The effects of carbamazepine in the intrahippocampal kainate model of temporal lobe epilepsy depend on seizure definition and mouse strain

Objective

Mesial temporal lobe epilepsy (TLE) with hippocampal sclerosis is a predominant form of acquired epilepsy, characterized by recurrent simple and complex partial seizures that are often resistant to treatment. Mice developing spontaneous recurrent nonconvulsive and convulsive seizures after intrahippocampal injection of the excitotoxic glutamate agonist kainate are thought to represent a valuable model of mesial TLE. Epileptic electroencephalogram (EEG) activity recorded in this model from the kainate focus in the ipsilateral hippocampus is resistant to antiseizure drugs such as carbamazepine (CBZ). We compared the efficacy of CBZ in this model in two different mouse strains (FVB/N and NMRI). Furthermore, we evaluated whether changes in the definition of electrographic seizures affect the antiseizure efficacy of CBZ.

Methods

As in previous studies, two types of epileptic EEG activity were defined: high-voltage sharp waves (HVSWs) and hippocampal paroxysmal discharges (HPDs). The characteristics of these paroxysmal EEG events in epileptic mice were compared with EEG criteria for nonconvulsive seizures in patients. For HVSWs, different spike frequencies, interevent intervals, and amplitudes were used as inclusion and exclusion criteria. In addition to CBZ, some experiments were performed with diazepam (DZP) and phenobarbital (PB).

Results

Female epileptic FVB/N mice predominantly exhibited frequent HVSWs, but only infrequent HPDs or secondarily generalized convulsive seizures. Slight changes in HVSW definition determined whether they were resistant or responsive to CBZ. Male NMRI mice exhibited both HVSWs and HPDs. HVSWs were more resistant than HPDs to suppression by CBZ. Both types of epileptic EEG activity were rapidly suppressed by DZP and PB.

Significance

The data demonstrate that focal electrographic seizures in the intrahippocampal kainate mouse model are less resistant than previously thought. Both mouse strain and the criteria chosen for definition of EEG seizures determine whether such seizures are drug-resistant or -responsive.

White matter in temporal lobe epilepsy: clinico-pathological correlates of water diffusion abnormalities

Using magnetic resonance imaging, it is possible to measure the behavior of diffusing water molecules, and the metrics derived can be used as indirect markers of tissue micro-architectural properties. Numerous reports have demonstrated that patients with temporal lobe epilepsy (TLE) have water diffusion abnormalities in several white matter structures located within and beyond the epileptogenic temporal lobe, showing that TLE is not a focal disorder, but rather a brain network disease. Differences in severity and spatial extent between patients with or without mesial temporal sclerosis (MTS), as well as differences related to hemispheric seizure onset, are suggestive of different pathophysiological mechanisms behind different forms of TLE, which in turn result in specific cognitive disabilities. The biological interpretation of diffusion abnormalities is based on a wealth of information from animal models of white matter damage, and is supported by recent reports that directly correlate diffusion metrics with histological characteristics of surgical specimens of TLE patients. Thus, there is now more evidence showing that the increased mean diffusivity (MD) and concomitant reductions of diffusion anisotropy that are frequently observed in several white matter bundles in TLE patients reflect reduced axonal density (increased extra-axonal space) due to smaller-caliber axons, and abnormalities in the myelin sheaths of the remaining axons. Whether these histological and diffusion features are a predisposing factor for epilepsy or secondary to seizures is still uncertain; some reports suggest the latter. This article summarizes recent findings in this field and provides a synopsis of the histological features seen most frequently in post-surgical specimens of TLE patients in an effort to aid the interpretation of white matter diffusion abnormalities.