The neuroendocrine basis of sex differences in epilepsy

Comparison of various doses of oral cannabidiol for treating refractory epilepsy indications: a network meta-analysis

Aim

To evaluate the comparative efficacy and safety of various doses of oral cannabidiol (CBD) in treating refractory epilepsy indications, thus providing more informative evidence for clinical decision-making.

Methods

A literature search of PubMed, Embase, the Cochrane library, and Web of Science (WoS) was performed to retrieve relevant randomized controlled trials (RCTs) that compared different doses of oral CBD with placebo or each other in refractory epilepsy indications. The search was limited from the inception of each database to January 3, 2023. Relative risk [RR] with a 95% confidence interval [CI] was used to express results. STATA/SE 14 was employed for network meta-analysis.

Results

Six RCTs involving 972 patients were included in the final data analysis. Network meta-analysis showed that, CBD10 (10 mg/kg/day) (RR: 1.77, 95%CI: 1.28 to 2.44), CBD20 (20 mg/kg/day) (RR: 1.91, 95%CI: 1.49 to 2.46), CBD25 (25 mg/kg/day) (RR: 1.61, 95%CI: 0.96 to 2.70), and CBD50 (50 mg/kg/day) (RR: 1.78, 95%CI: 1.07 to 2.94) were associated with higher antiseizure efficacy although the pooled result for CBD25 was only close to significant. In addition, in terms of the risk of treatment-emergent adverse events (TEAEs), the difference between different doses is not significant. However, CBD20 ranked first in terms of antiseizure efficacy, followed by CBD50, CBD10, and CBD25. For TEAEs, CBD25 ranked first, followed by CBD10, CBD50, CBD5, and CBD20.

Conclusion

For refractory indications, CBD20 may be optimal option for antiseizure efficacy; however, CBD25 may be best for TEAEs. Therefore, an appropriate dose of oral CBD should be selected based on the actual situation. Due to the limitations of eligible studies and the limited sample size, more studies are needed in the future to validate our findings.

Ictal activity is sustained by the estrogen receptor β during the estrous cycle

Catamenial epilepsy, defined as a periodicity of seizure exacerbation during the menstrual cycle, affects up to 70 % of epileptic women. Seizures in these patients are often non-responsive to medication; however, our understanding of the relation between menstrual cycle and seizure generation (i.e. ictogenesis) remains limited. We employed here field potential recordings in the in vitro 4-aminopyridine model of epileptiform synchronization in female mice (P60-P130) and found that: (i) the estrous phase favors ictal activity in the entorhinal cortex; (ii) these ictal discharges display an onset pattern characterised by the presence of chirps that are thought to mirror synchronous interneuron firing; and (iii) blocking estrogen receptor β-mediated signaling reduces ictal discharge duration. Our findings indicate that the duration of 4AP-induced ictal discharges, in vitro, increases during the estrous phase, which corresponds to the human peri-ovulatory period. We propose that these effects are caused by the presumptive enhancement of interneuron excitability due to increased estrogen receptor β-mediated signaling.

Estimating the active and lifetime prevalence and incidence of epilepsy in Asian Countries: A systematic review and meta-analysis

OBJECTIVE

In the current era of the World Health Organization's Intersectoral Global Action Plan on Epilepsy and Other Neurological Disorders 2022-2031 (IGAP), precise and updated estimates of epilepsy burden are vital in formulating policies to improve the care of persons with epilepsy, especially in Asian countries with significant treatment gap. Hence, we aimed to consolidate the available data and quantify epilepsy prevalence and incidence estimates in Asian countries.

METHODS

We systematically searched PubMed, Embase, Ovid, and Scopus databases from inception until March 2023 for studies reporting epilepsy prevalence and incidence in Asian countries. We applied random effects meta-analysis to generate the pooled prevalence and incidence using the Meta package in R. Additionally, we performed a subgroup meta-analysis to explore the potential sources of heterogeneity. A meta-regression analysis was conducted to examine the trend of epilepsy over time.

RESULTS

A total of 99 studies with 100,654,124 participants were included in the meta-analysis. The pooled prevalence was 5.6 per 1000 (95 % confidence interval (CI) 4.4-6.8) for active epilepsy and 6.7 per 1000 (95 % CI 5.7-7.9) for lifetime epilepsy. The pooled incidence rate of epilepsy was 52.5 per 100,000 person-years (95 % CI 42.7-79.4). The subgroup analysis revealed a higher prevalence of active epilepsy (6.7/1000) and lifetime epilepsy (8.6/1000) in West Asia than in other regions. The funnel plot and Egger's test (p-value =<0.0001) revealed publication bias for active epilepsy.

CONCLUSION

Our findings highlight a high prevalence of active and lifetime epilepsy in West Asia and emphasize the necessity of implementing and formulating specific strategies to tackle the epilepsy burden in this region. Furthermore, high-quality epidemiological studies incorporating economic burdens and comorbidities associated with epilepsy in Asia are still needed.

Multiomic analysis implicates nuclear hormone receptor signalling in clustering epilepsy

Clustering Epilepsy (CE) is an epileptic disorder with neurological comorbidities caused by heterozygous variants of the X chromosome gene Protocadherin 19 (PCDH19). Recent studies have implicated dysregulation of the Nuclear Hormone Receptor (NHR) pathway in CE pathogenesis. To obtain a comprehensive overview of the impact and mechanisms of loss of PCDH19 function in CE pathogenesis, we have performed epigenomic, transcriptomic and proteomic analysis of CE relevant models. Our studies identified differential regulation and expression of Androgen Receptor (AR) and its targets in CE patient skin fibroblasts. Furthermore, our cell culture assays revealed the repression of PCDH19 expression mediated through ERα and the co-regulator FOXA1. We also identified a protein-protein interaction between PCDH19 and AR, expanding upon the intrinsic link between PCDH19 and the NHR pathway. Together, these results point to a novel mechanism of NHR signaling in the pathogenesis of CE that can be explored for potential therapeutic options.

The neuropsychological presentation of women with epilepsy: clinical considerations and future directions

Objective: Cognitive, mood, and behavioral changes are common among persons with epilepsy (PWE), resulting in a complex neuropsychological presentation. Women with epilepsy (WWE) represent a distinct cohort within the broader epilepsy population due to sex and gender-specific factors impacting epilepsy semiology and treatment. However, unique neuropsychological profiles among WWE have not been established. This narrative review aims to further define neuropsychological correlates in WWE and promote meaningful discussion related to enhancing the provision of neuropsychological care within this clinical population. Method: Current literature in PWE examining differences in cognitive function, mental health, and quality of life (QoL) between women and men was critically reviewed, emphasizing considerations for neuropsychological practice. Results: WWE demonstrate a preservation of verbal learning and memory compared to men both pre- and post-surgically, with sex-based, neurobiological mechanisms likely contributing to this association. WWE also have elevated risk for affective disorder psychopathology, suicidality, and traumatic experiences. Epidemiology related to psychotic and bipolar spectrum disorders is less clear, and findings are mixed regarding sex-specific behavioral side effects of antiseizure and psychotropic medication. Finally, hormonal and obstetric factors are highlighted as important contributors to neuropsychological symptoms in WWE, with elevated risk for low QoL and increased stigma associated with greater medical and psychiatric comorbidities compared to men. Conclusions: While emerging literature has begun to characterize the neuropsychological presentation of WWE, future research is needed to define sex and gender differences in neuropsychological sequalae among PWE to ensure consistency and quality of care for WWE.

Predictors of adverse effects to antiseizure drugs in adult patients with epilepsy from Colombia: A case-control study

INTRODUCTION

Adverse drug reactions (ADRs) to antiseizure therapy can worsen the quality of life, reduce adherence, and potentially lead to treatment discontinuation and uncontrolled seizures.

OBJECTIVES

The aim of the study was to develop a prognostic model for ADRs to antiseizure therapy in adult patients with epilepsy from Colombia.

METHODS

This case-control study included adult patients with epilepsy, who were separated into two groups: one group with ADRs to antiseizure therapy (cases), as determined by a complete evaluation conducted by an epileptologist, and another group without ADRs (controls). Variables were analyzed to identify statistical differences between the two groups and were then selected to construct a prognostic model using logistic regression. The Bonferroni method was applied for multiple comparisons.

RESULTS

Three hundred fifty-four patients with epilepsy were studied. One hundred and fifty (42%) patients had ADRs and 204 (57%) patients did not have ADs. A total of 362 ADRs were reported, with a third of them being general symptoms and most frequently occurring with older-generation antiseizure drugs (58%). Female sex, drug-resistant epilepsy, LEV, and CZP were risk factors, whereras the presence of tumoral etiology, absence of seizure triggers, and VPA were identified as protective factors. A prognostic model was constructed using previously reported risk factors for ADRs to antiseizure therapy and other variables available in this population study. In the multivariable analysis, the number of previously used antiseizure drugs (1, 2, or ≥3), TPM, CZP, LEV, PHT, and female sex were predictors of ADRs. The corrected p-values were estimated by the Bonferroni method; however, not all the variables achieved statistical significance with this adjustment.

CONCLUSIONS

In adult patients with epilepsy from Colombia, we found that the number of previously used antiseizure drugs, TPM, CZP, LEV, PHT, and female sex were predictive factors for ADRs to antiseizure therapy.

Catamenial epilepsy occurrence and patterns in a mixed population of women with epilepsy

We evaluated the occurrence and distribution of patterns of catamenial epilepsy in a heterogenous cohort of women with epilepsy on no hormonal therapies, enrolled in a prospective, observational study. The primary aim of the study was pregnancy rate in women with epilepsy with no prior reproductive problems. In this analysis, we included women who recorded one or more menstrual cycles with one or more seizures. We measured progesterone concentrations for one to three cycles. We defined catamenial patterns as twofold or greater average daily seizure frequency around menstruation (C1), ovulation (C2), and for anovulatory cycles, from midcycle through menstruation (C3). Twenty-three of the 89 enrolled women with epilepsy were eligible for this analysis; 12 of 23 met criteria for catamenial epilepsy; five of 23 demonstrated only a C1 pattern, two of 23 only a C2 pattern, five of 23 a combined C1/C2 pattern, and the one woman with anovulatory cycles did not demonstrate a C3 pattern. There were no differences in likelihood of demonstrating a catamenial pattern between those who reported a prior catamenial pattern and those who did not (p = .855). This analysis demonstrates the utility of app-based tracking to determine a catamenial pattern. Larger prospective studies could confirm these findings and inform potential therapeutic trial designs for catamenial epilepsy.

Clinical risk factors related to post-stroke epilepsy patients in Indonesia: a hospital-based study

Background

Stroke had been accounted to cause almost 50% of epilepsy in the elderly and may lead to poor functional outcomes. Many studies examining the risk factors have been conducted despite showing inconsistent results and currently still difficult to predict the occurrence of post-stroke epilepsy. The study aimed to determine risk factors related to post-stroke epilepsy that influence clinical seizure, electroencephalography (EEG), and functional outcome of patients. Analytic retrospective case–control study was conducted with a total sampling of 62 samples of post-stroke epilepsy and 62 samples of control from all stroke patients in the Neurology Clinic from January 2019 to December 2021. Epilepsy was classified according to the criteria of the International League Against Epilepsy (ILAE) in 2017. The relevant demographic and clinical data were collected.

Result

The study involved 62 patients in the case group (average age of onset = 57.69; 42 men, 20 women; 51 ischemic stroke, 11 hemorrhagic stroke) and 62 patients in the control group (average age of onset = 56.90; 24 men, 38 women; 52 ischemic stroke, 10 hemorrhagic stroke). We found that 31 patients had focal-to-bilateral seizures, 26 patients had generalized seizures and 5 patients had focal seizures. Men (p = 0.001; OR 3.325) and NIHSS Score (p = 0.027; OR 5.094) had significant correlations with post-stroke epilepsy. Ischemic stroke had a significant correlation (p = 0.008) with seizure onset. Women also had a significant correlation (p = 0.012) with EEG abnormalities. The study found that 59 of 62 post-stroke epilepsy patients had poor functional outcomes (mRS > 2).

Conclusion

Our study confirmed that most patients had focal-to-bilateral seizure patterns that occurred in 1–2 years after stroke, and had poor functional outcomes. Men had 3.325 times more likely to develop post-stroke epilepsy than women. Also, NIHSS score ≥ 15 correlated and 5.094 times more likely to develop post-stroke epilepsy. Ischemic stroke had a peak of epilepsy onset at 1–2 years after stroke and women had significant showing abnormalities on EEG recording than men.

The effect of age at onset of type 1 diabetes mellitus on epilepsy vulnerability

AIMS

To examine whether type 1 diabetes age onset correlates with epilepsy incidence.

METHODS

We used type 1 diabetes longitudinal data with onset age ≤ 40 years enrolled in Taiwan National Health Insurance program to examine type 1 diabetes onset age effect on epilepsy occurrence.

RESULTS

In 6,165 type 1 diabetes patients, onset age groups included 3,571 patients (58%) ≤ 18 years (childhood-onset) and 2,594 patients (42%) > 18 years (adulthood-onset). After 8.6 years median follow-up following type 1 diabetes onset, epilepsy incidence rate in adulthood-onset group was 2.26-fold higher than that in childhood-onset group. Epilepsy incidence rate ratio was lowest in those with onset age 6-12 years in comparison to that in patients with onset age ≤ 6 years, but was highest in onset age of 30-40 years. Longer follow-up duration correlates with higher epilepsy risk in adulthood-onset group. Multiple logistic regression analysis showed that onset age 30-40 years, male, more than one diabetic ketoacidosis episode, and unprovoked seizure events were independent risk factors for epilepsy following type 1 diabetes onset.

CONCLUSIONS

There is age-related vulnerability to epilepsy following type 1 diabetes onset. Adulthood-onset type 1 diabetes is an independent risk factor for epilepsy susceptibility after type 1 diabetes.

Clinical efficacy and safety of cannabidiol for pediatric refractory epilepsy indications: A systematic review and meta-analysis

Antiseizure medications (ASMs) are the mainstay for the treatment of seizure disorders. However, about one-third of people with epilepsy remain refractory to current ASMs. Cannabidiol (CBD) has recently been approved as ASM for three refractory epilepsy syndrome indications in children and adults. In this study, we evaluated the overall clinical potential of an oral CBD to treat refractory epilepsy in patients with Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC) through a systematic review and meta-analysis. A comprehensive search of databases was conducted, including randomized controlled trials (RCTs) assessing the effect of CBD in epilepsy patients. The review was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The review focused on RCTs involving patients receiving highly purified oral CBD (Epidiolex, 10 to 50 mg/kg/day) for up to 16 weeks. A subgroup analysis by syndrome and CBD with or without concomitant clobazam was conducted. The key outcomes were reduction in seizure frequency, differences in 50% responder rates, adverse events, and interactions with clobazam as co-therapy. Odds ratio (OR) with 95% confidence interval (CI) were estimated. Of 1183 articles screened, we included 6 RCTs meeting our eligibility criteria. All studies were considered to have a low risk of bias. In the pooled analysis, CBD treatment was found to be more efficacious compared to placebo (OR = 2.45, 95% CI =1.81-3.32, p < 0.01). Subgroup analysis by syndrome demonstrated the odds of ≥50% reduction in seizures with CBD treatment in patients with DS (OR = 2.26, 95% CI:1.38-3.70), LGS (OR = 2.98, 95% CI:1.83-4.85) and TSC (OR = 1.99, 95% CI = 1.06-3.76). Compared with placebo, CBD was associated with increased adverse events (OR = 1.81, 95% CI = 1.33-2.46) such as diarrhea, somnolence, and sedation, and any serious adverse events (OR = 2.86, 95% CI = 1.63-5.05). Other factors, including dosage and clobazam co-therapy, were significantly associated with a greater effect on seizure control and side effects of CBD. In conclusion, the study shows that CBD is highly efficacious both as standalone and adjunct therapy with clobazam for controlling seizures in DS, LGS, and TSC conditions while limiting side effects. Further pharmacodynamic investigation of CBD actions, drug interaction assessments, and therapeutic management guidelines are warranted.

Health Disparities in Pediatric Epilepsy: Methods and Lessons Learned

Epilepsy affects 1% of youth and is associated with neurocognitive and psychosocial comorbidities, increased risk of mortality, and poor health-related outcomes. Health disparities in children and youth with epilepsy (CYE) have been understudied. A Special Interest Group (SIG) within the Pediatric Epilepsy Research Consortium is conducting a scoping review to systematically assess the literature and highlight the gaps in access to clinical care and management of pediatric epilepsy. The methodology for this review is presented. In conducting a peer-reviewed assessment of the scope of health disparities in pediatric epilepsy, we learned that developing the methodology for and conducting a comprehensive scoping review with multiple contributors resulted in a time-intensive process. While there is an evidence to suggest that health disparities do exist in CYE, very few studies have focused on these disparities. Disparity results are often not included in key elements of articles, lending them to be underemphasized and underrecognized. Preliminary conclusions inform several important research considerations.

Gender differences in prevalence and risk factors of sleep disturbances in patients with epilepsy

Background

Sleep disturbances are frequently observed in patients with epilepsy (PWE), with adversely effects on life quality and seizure control. The study aimed to assess the gender differences in incidence and factors of sleep disturbances in PWE.

Methods

PWE confirmed the diagnosis of epilepsy were consecutively enrolled in this cross-sectional study, with detailed information recorded. A group of healthy participants were recruited as the control. Sleep and mood disorders were evaluated with the Insomnia Severity Index (ISI), Pittsburgh Sleep Quality Index (PSQI), Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI).

Results

One hundred and thirty-three patients (age: 30.2 ± 10.6 years, men: 51%) and 150 healthy subjects were recruited in this study. Compared with healthy controls, PWE had higher mean scores of the ISI and BDI (p < 0.001 and p = 0.01). There were no significant gender differences in the prevalence and scores of sleep disturbances in PWE. In the overall PWE, nocturnal seizures and focal epilepsy were respectively related to insomnia and poor sleep quality (OR = 3.35, p = 0.024; OR = 3.08, p = 0.013), and mood disorders were also important factors in sleep disturbances (p < 0.05). In the analysis by gender, depression, anxiety, nocturnal seizures and focal epilepsy were associated with insomnia and poor sleep quality in men. For women, however, depression mood was the only factor of sleep disturbances.

Conclusions

Though no gender difference was observed in the incidence of sleep disturbances, factors contributing to insomnia and sleep quality were different by gender. The factors and gender differences of sleep disturbances should be taken into account in the clinical treatment.

Efficacy of Phenobarbital and Prognosis Predictors in Women With Epilepsy From Rural Northeast China: A 10-Year Follow-Up Study

Objective

To investigate the efficacy of phenobarbital (PB), factors associated with it, reasons for early treatment termination, and mortality rates in adult women living in rural Northeast China.

Methods

A prospective study was conducted in seven counties of Jilin Province from 2010 to 2020. Adult women diagnosed with convulsive epilepsy were recruited into the study and baseline demographics recorded upon enrollment. Seizure frequency, prescribed drug dose, and adverse reactions were monitored monthly by door-to-door survey or telephone interview.

Results

A total of 1,333 women were included in the study. During the follow-up period, 169 participants (12.7%) were lost to follow-up, and 100 of them (7.5%) died. The percentage of seizure-free participants was 45.3% in the first year, 74.6% in the third year, and 96.6% in the 10th year. A higher baseline seizure frequency (OR = 1.005, 95% CI: 1.002–1.009), more frequent loss-of-consciousness seizures (OR = 1.620, 95% CI: 1.318–1.990), a higher daily dose of PB in the first year (OR = 1.018, 95% CI: 1.014–1.022), a younger age at onset (OR = 0.990, 95% CI: 0.982–0.998), and more severe drowsiness (OR = 1.727, 95% CI: 1.374–2.173) were associated with an increased risk of seizures in the first year, and the higher baseline seizure frequency was still associated with the occurrence of seizures in the third (OR = 1.007, 95% CI: 1.004–1.010) and fifth year (OR = 1.005, 95% CI: 1.002–1.008). Age at enrollment (HR = 0.983, 95% CI: 0.971–0.994) was the only factor that correlated with withdrawal from the study and with the death of the participant during the follow up period, but the correlation in each case was in opposite directions.

Significance

PB has high effectiveness, retention rate, mild side effects, and tolerability when used as a treatment for epilepsy in women from rural areas. Baseline seizure frequency is an important predictor of prognosis regardless of treatment duration. PB is still a valuable tool for the management of epilepsy in adult women from poverty-stricken areas.

TOPIRAMATE-INDUCED BILATERAL ANGLE-CLOSURE GLAUCOMA. A CASE REPORT

INTRODUCTION

Topamax (topiramate) is a drug used in the treatment of epilepsy or migraine. Its use may rarely be associated with the occurrence of secondary angle-closure glaucoma due to supraciliary effusion. Although the ocular finding resembles primary angle-closure glaucoma, bilateral infliction should always raise the suspicion that it is drug-induced glaucoma.

CASE REPORT

The authors present a case of a 51-year-old patient on Topamax therapy with sudden vertigo, headache and blurred vision. Ophthalmic examination revealed bilateral angle-closure glaucoma, which was initially treated in the classical manner by administration of local antiglaucoma drugs and pilocarpine, followed by administration of osmotically active substances and laser iridotomy. Only the subsequent discontinuation of Topamax and the use of local cycloplegics and corticosteroids led to the release of the anterior segment angle closure and normalization of intraocular pressure.

CONCLUSION

The indicating physician and ophthalmologist must be aware of the possible side effects of Topamax therapy to determine the correct diagnosis and to administer treatment appropriately.

Meta-analysis of epigenome-wide association studies in newborns and children show widespread sex differences in blood DNA methylation

BACKGROUND

Among children, sex-specific differences in disease prevalence, age of onset, and susceptibility have been observed in health conditions including asthma, immune response, metabolic health, some pediatric and adult cancers, and psychiatric disorders. Epigenetic modifications such as DNA methylation may play a role in the sexual differences observed in diseases and other physiological traits.

METHODS

We performed a meta-analysis of the association of sex and cord blood DNA methylation at over 450,000 CpG sites in 8438 newborns from 17 cohorts participating in the Pregnancy And Childhood Epigenetics (PACE) Consortium. We also examined associations of child sex with DNA methylation in older children ages 5.5-10 years from 8 cohorts (n = 4268).

RESULTS

In newborn blood, sex was associated at Bonferroni level significance with differences in DNA methylation at 46,979 autosomal CpG sites (p < 1.3 × 10-7) after adjusting for white blood cell proportions and batch. Most of those sites had lower methylation levels in males than in females. Of the differentially methylated CpG sites identified in newborn blood, 68% (31,727) met look-up level significance (p < 1.1 × 10-6) in older children and had methylation differences in the same direction.

CONCLUSIONS

This is a large-scale meta-analysis examining sex differences in DNA methylation in newborns and older children. Expanding upon previous studies, we replicated previous findings and identified additional autosomal sites with sex-specific differences in DNA methylation. Differentially methylated sites were enriched in genes involved in cancer, psychiatric disorders, and cardiovascular phenotypes.

Factors not considered in the study of drug-resistant epilepsy: Psychiatric comorbidities, age and gender

In basic research and clinical practice, the control of seizures has been the most important goal but it should not be the only one. There are factors that remain poorly understood in the study of refractory epilepsy such as the age and gender of patients and the presence of psychiatric comorbidities. It is known that in patients with drug-resistant epilepsy (DRE), the comorbidities contribute to the deterioration of the quality of life, increase the severity, and worsen the prognosis of epilepsy. Some studies have demonstrated that patients diagnosed with a co-occurrence of epilepsy and psychiatric disorders are more likely to present refractory seizures and the probability of seizure remission after pharmacotherapy is reduced. The evidence of this association suggests the presence of shared pathogenic mechanisms that may include endocrine disorders, neuroinflammatory processes, disturbances of neurotransmitters and mechanisms triggered by stress. Additionally, significant demographic, clinical and electrographic differences have been observed between women and men with epilepsy. Epilepsy affects the female gender in a greater proportion, although there are no studies that report whether refractoriness affects more females. The reasons behind these sex differences are unclear; however, it is likely that sex hormones and sex brain differences related to chromosomal genes play an important role. On the other hand, it has been shown in industrialized countries that prevalence of DRE is higher in the elderly when compared to youngsters. Conversely, this phenomenon is not observed in developing regions, where more cases are found in children and young adults. The correct identification and management of these factors is crucial in order to improve the quality of life of the patients.

Burden of epilepsy in Latin America and The Caribbean: a trend analysis of the Global Burden of Disease Study 1990 - 2019

Background

The epilepsy prevalence in Latin America and the Caribbean (LAC) had remained high over the last 20 years. Data on the burden of epilepsy are needed for healthcare planning and resource allocation. However, no systematic analysis had been performed for epilepsy burden in LAC.

Methods

We extracted data of all LAC countries from the Global Burden of Disease (GBD) study from 1990 to 2019. Epilepsy burden was measured as prevalence, mortality, and disability-adjusted life-years (DALYs; defined by the sum of years of life lost [YLLs] for premature mortality and years lived with disability [YLDs]), by age, sex, year, and country. Absolute numbers, rates, and 95% uncertainty intervals were reported. We performed correlational analyses among burden metrics and Socio-demographic Index (SDI).

Findings

The burden of epilepsy decreased around 20% in LAC, led by YLLs reduction. In 2019, 6·3 million people were living with active epilepsy of all causes (95% UI 5·3 - 7·4), with 3·22 million (95% UI 2·21 - 4·03) and 3·11 million (95% UI 2·21 to 4·03) cases of epilepsy with identifiable aetiology and idiopathic epilepsy, respectively. The number of DALYs represented the 9·51% (1.37 million, 95% UI 0·99 -1·86) of the global epilepsy burden in 2019. The age-standardized burden was 175·9 per 100 000 population (95% UI 119·4 - 253·3), which tend to have a bimodal age distribution (higher in the youth and elderly) and was driven by high YLDs estimates. The burden was higher in men and older adults, primarily due to high YLLs and mortality. Alcohol use was associated with 17% of the reported DALYs. The SDI estimates significantly influenced this burden (countries with high SDI have less epilepsy burden and mortality, but not prevalence or disability).

Interpretation

The epilepsy burden has decreased in LAC over the past 30 years. Even though, LAC is still ranked as the third region with the highest global epilepsy burden. This reduction was higher in children, but burden and mortality increased for older adults. The epilepsy burden is disability predominant; however, the mortality-related estimates are still higher than in other regions. Alcohol consumption and countries' development are important determinants of this burden. There is an urgent need to improve access to epilepsy care in LAC, particularly for older adults. Strengthening primary care with online learning and telemedicine tools, and promoting risk factors modification should be prioritized in the region.

Funding

This research was self-funded by the authors.

Screening of prototype antiseizure and anti-inflammatory compounds in the Theiler's murine encephalomyelitis virus model of epilepsy

OBJECTIVE

Infection with Theiler's murine encephalomyelitis virus (TMEV) in C57Bl/6J mice results in handling-induced seizures and is useful for evaluating compounds effective against infection-induced seizures. However, to date only a few compounds have been evaluated in this model, and a comprehensive study of antiseizure medications (ASMs) has not yet been performed. Furthermore, as the TMEV infection produces marked neuroinflammation, an evaluation of prototype anti-inflammatory compounds is needed as well.

METHODS

Male C57Bl/6J mice were inoculated with TMEV (day 0) followed by daily administrations of test compounds (day 3-7) and subsequent handling sessions (day 3-7). Doses of ASMs, comprising several mechanistic classes, were selected based on previously published data demonstrating the effect of these compounds in reducing seizures in the 6 Hz model of pharmacoresistant seizures. Doses of anti-inflammatory compounds, comprising several mechanistic classes, were selected based on published evidence of reduction of inflammation or inflammation-related endpoints.

RESULTS

Several prototype ASMs reduced acute seizures following TMEV infection: lacosamide, phenytoin, ezogabine, phenobarbital, tiagabine, gabapentin, levetiracetam, topiramate, and sodium valproate. Of these, phenobarbital and sodium valproate had the greatest effect (>95% seizure burden reduction). Prototype anti-inflammatory drugs celecoxib, dexamethasone, and prednisone also moderately reduced seizure burden.

SIGNIFICANCE

The TMEV model is utilized by the Epilepsy Therapy Screening Program (ETSP) as a tool for evaluation of novel compounds. Compounds reducing seizures in the TMEV comprise distinct mechanistic classes, some with mechanisms of action that extend beyond traditional ASMs.

Pregnant women with more seizures have lower allopregnanolone concentrations

Neuroactive steroids have rapid, nongenomic effects on neuronal excitability. The effects in humans are less clear. We compared seizure control and concentrations of neuroactive steroids, known to influence neuroexcitability in animal studies, in pregnant women. Participants were prospectively followed throughout pregnancy with seizure-medication diaries and blood samples, assayed for steroid concentrations with gas chromatography-mass spectrometry. Baseline seizure frequency was calculated for the preconception year, and it was determined if seizure frequency was increased in each trimester. The Wilcoxon rank-sum test was used to compare neuroactive steroid concentrations in between the group with increased frequency to the group without, as calculated for the respective trimester, with the Holm-Bonferroni method to correct for multiple comparisons. Among eighty-three pregnancies included, twenty-eight had increased seizure frequency during at least one trimester (15, 18 and 10, respectively) compared to preconception seizure frequency. Allopregnanolone concentrations were lower in the 3rd trimester (p < 0.001), with a similar trend in the 1st (p = 0.08), for pregnancies with increased compared to those with stable seizure frequency. Other neuroactive steroid concentrations were similar. Our findings suggest that lower allopregnanolone concentrations are associated with increased seizure frequency during pregnancy. Validation of these finding in a larger cohort has potential important clinical applications.

Association between IDH mutational status and tumor-associated epilepsy or venous thromboembolism in patients with grade II and III astrocytoma

In previous studies, isocitrate dehydrogenase (IDH) mutations were associated with tumor-associated epilepsy (TAE) and venous thromboembolism (VTE). We examined the relationship between IDH mutations in grade II/III astrocytomas and TAE/VTE according to the 2016 World Health Organization classification. The clinical data of patients with newly diagnosed grade II/III gliomas who were treated at Tohoku University Hospital from January 2010 to December 2018 were reviewed. Associations between TAE or VTE and the clinical/biological characteristics, histology, and IDH1/2 mutational status in patients with grade II/III gliomas were evaluated. Of the initial 137 patients (290 hospitalizations), 117 patients (203 hospitalizations) were included in the TAE group and 124 patients (213 hospitalizations) were included in the VTE group. Seventy-eight patients (66.7%) in the TAE group were diagnosed with astrocytoma and 38/78 (48.3%) presented with TAE. According to the multivariable analysis, the IDH mutational status and male sex were associated independently with an increased risk of TAE (p < 0.05). Eighty-five patients (68.5%) in the VTE group were diagnosed with astrocytoma. VTE was observed in 16/161 (9.9%) hospitalizations. According to the multivariable analysis, age, diffuse astrocytoma histology, and resection were associated independently with an increased risk of VTE. The decision tree analysis showed that TAE was more frequent in younger patients while VTE was more frequent in older patients. This study demonstrated that the IDH mutational status was associated with TAE but not with VTE. Therefore, a future large-scale study is needed to provide sufficient evidence. TAE was more common in young patients, while VTE was more common in the elderly.

Gender differences in geriatric syndromes as mental illness and nervous system diseases in hospitalized Thai older patients

BACKGROUND

Older persons are affected by mental and neurological disorders differently, and gender plays a significant role influencing geriatric disorder differentiation. Accordingly this study characterized gender differences in geriatric syndromes among hospitalized elderly Thai patients.

METHODS

Probabilities of disease occurrence reflecting gender differences were calculated using historical data obtained from the Ministry of Public Health website, Thailand. We selected older patients aged 60 years and above admitted to inpatient departments in public hospitals with mental disorders and nervous system diseases from 2014 to 2018, counting over 160 000 cases each year. Descriptive statistics and odds ratios (ORs) were used to analyse and demonstrate gender differences.

RESULTS

Compared to older females, older males had higher occurrences of four mental disorders revealed by OR and 95% confidence interval (CI) values: substance abuse (5.74, 5.08-6.49), alcohol use (5.66, 5.44-5.89), behavioural problems (1.34, 1.31-1.37), and schizophrenia (1.10, 1.06-1.14). Lower incidences for older males were seen in the same values for three mental disorders: neurotic issues (0.46, 0.44-0.49), mood disorders (0.58, 0.56-0.60), and dementia (0.91, 0.88-0.94). For neurological disorders, men had similar higher incidences for epilepsy (1.67, 1.63-1.72), cerebral palsy (1.61, 1.57-1.65), nervous system inflammatory diseases (1.53, 1.46-1.60), ischaemic attacks (1.42, 1.36-1.48), miscellaneous other nervous disorders (1.20; 1.18-1.22), and Parkinson's disease (1.15, 1.12-1.19). By contrast, older men had lower incidences of multiple sclerosis (0.55, 0.35-0.86), migraines (0.66, 0.62-0.70), and Alzheimer's disease (0.75, 0.71-0.78).

CONCLUSION

Accurate characterization of gender differences in geriatric syndromes can better inform policies for appropriate early detection and prevention, and contribute to the development of treatment and intervention for various issues affecting elderly men and women's health.

Absence epilepsy in male and female WAG/Rij rats: A longitudinal EEG analysis of seizure expression

The WAG/Rij strain of rats is commonly used as a preclinical model of genetic absence epilepsy. While widely utilized, the developmental trajectory of absence seizure expression has been only partially described. Moreover, sex differences in this strain have been under-explored. Here, we longitudinally monitored male and female WAG/Rij rats to quantify cortical spike-and-wave discharges (SWDs) monthly, from 4 to 10 months of age. In both male and female WAG/Rij rats, absence seizure susceptibility increased with age. In contrast to previous reports, we found a robust and consistent increase in absence epilepsy susceptibility in male WAG/Rij rats in comparison to females across months. The increased absence seizure susceptibility was characterized by increased number and duration of SWDs, and consequently increased total SWDs duration. These findings highlight a previously un-recognized sex difference in a model of absence epilepsy and narrow the knowledge gap of age-dependent expression of SWDs in the WAG/Rij strain.

Molecular mechanisms of sex differences in epilepsy and seizure susceptibility in chemical, genetic and acquired epileptogenesis

This article provides a succinct overview of sex differences in epilepsy and putative molecular mechanisms underlying sex differences in seizure susceptibility in chemical, genetic, and acquired epileptogenesis. The susceptibility to excitability episodes and occurrence of epileptic seizures are generally higher in men than women. The precise molecular mechanisms remain unclear, but differences in regional morphology and neural circuits in men and women may explain differential vulnerability to seizures and epileptogenic cascades. Changes in seizure sensitivity can be attributed to steroid hormones, including fluctuations in neurosteroids as well as neuroplasticity in their receptor signaling systems. Other potential neurobiological bases for sex differences in epilepsies include differences in brain development, neurogenesis, neuronal chloride homeostasis, and neurotrophic and glial responses. In catamenial epilepsy, a gender-specific neuroendocrine condition, epileptic seizures are most often clustered around a specific menstrual period in adult women. A deeper understanding of the molecular and neural network basis of sex differences in seizures and response to antiepileptic drugs is highly warranted for designing effective, sex-specific therapies for epilepsy, epileptogenesis, and seizure disorders.

Gender and Socioeconomic Disparities in Global Burden of Epilepsy: An Analysis of Time Trends From 1990 to 2017

Objective: The objective of the study is to investigate the gender and socioeconomic disparities in the global burden of epilepsy by prevalence and disability-adjusted life-years (DALYs).

Methods: The global, regional, and national gender-specific prevalence and DALYs caused by epilepsy by year and age were extracted from the Global Burden of Disease (GBD) Study 2017. The Gini coefficient and concentration index (CI) were calculated to demonstrate the trends in between-country inequality in the epilepsy burden from 1990 to 2017. Paired Wilcoxon signed rank test, Pearson correlation, and linear regression analyses were performed to analyze the association of gender disparity in epilepsy and socio-demographic index (SDI).

Results: The DALYs number of epilepsies increased from 1990 to 2017 by 13.8%, whereas age-standardized DALY rates showed a substantial reduction (16.1%). Men had a higher epilepsy burden than women of the same period. The epilepsy burden appeared to be higher in countries with lower socioeconomic development (CI < 0). The Gini coefficient decreased from 0.273 in 1995 to 0.259 in 2017, representing a decline in the between-country gap. Age-standardized prevalence and DALY rates of men were higher than those of women in each SDI-based country group (p < 0.0001). Male-minus-female difference (r = −0.5100, p < 0.0001) and male-to-female ratio (r = −0.3087, p < 0.0001) of age-standardized DALY rates were negatively correlated with SDI.

Conclusion: Although global health care of epilepsy is in progress, the epilepsy burden was concentrated in males and developing countries. Our findings highlight the importance of formulating gender-sensitive health policies and providing more services in developing countries.

Dehydroepiandrosterone (DHEA) Serum Levels Indicate Cerebrospinal Fluid Levels of DHEA and Estradiol (E2) in Women at Term Pregnancy

Neuroactive steroids such as dehydroepiandrosterone (DHEA), estradiol (E2), and progesterone (P4) are associated with structural and functional changes in the central nervous system (CNS). Measurement of steroid levels in the CNS compartments is restricted in accessibility. Consequently, there is only limited human data on the distributional equilibrium for steroid levels between peripheral and central compartments. While some neuroactive steroids including DHEA and E2 have been reported to convey excitatory and proconvulsant properties, the opposite was demonstrated for P4. We aimed to elucidate the correlation between peripheral and central DHEA, E2, and P4 levels in women at term pregnancy. CSF and serum samples of 27 healthy pregnant women (22–39 years) at term pregnancy were collected simultaneously under combined spinal and epidural anesthesia and used for DHEA ELISA and E2, and P4 ECLIA. All three neuroactive steroids were detected at markedly lower levels in CSF compared to their corresponding serum concentrations (decrease, mean ± SD, 97.66 ± 0.83%). We found a strong correlation for DHEA between its serum and the corresponding CSF levels (r = 0.65, p = 0.003). Serum and CSF levels of E2 (r = 0.31, p = 0.12) appeared not to correlate in the investigated cohort. DHEA serum concentration correlated significantly with E2 (r = 0.58, p = 0.0016) in CSF. In addition, a strong correlation was found between DHEA and E2, both measured in CSF (r = 0.65, p = 0.0002). Peripheral DHEA levels might serve as an indicator for central nervous levels of the neuroactive steroids DHEA and E2 in pregnant women.

The promises and pitfalls of sex difference research

Funding agencies in North America and Europe are recognizing the importance of the integration of sex differences into basic and clinical research. Although these mandates are in place to improve our knowledge of health for both men and women, there have been a number of implementation issues that require vigilance on the part of funders and the research community. Here we discuss issues on simple inclusion of both sexes in studies to specialisation of sex differences with attention paid to statistics and the need for sex-specific treatments. We suggest differing mandates need to be considered regarding simple integration versus the need for studies in the specialisation of sex differences and/or the need for research that recognises the importance of male-specific or female-specific factors that influence subsequent health such as menstruation, menopause or pregnancy.

Detection of the steroid receptor interacting protein, PAK6, in a neuronal cell line

PAK6 is a Group II p21 activated kinase that unlike traditional signal transduction proteins interacts with multiple binding partners including sex-steroid receptors. PAK6 acts as a nodal checkpoint integrating multiple cellular inputs to promote distinct cellular outcomes, some of which are associated with cytoskeletal remodeling. Despite the possibility that PAK6 may couple sex-specific neuronal function and therefore serve as a valuable research, diagnostic and therapeutic target, there is currently no standardized protocol for assessing PAK6 activity in a neuronal cell line. Here, we present a protocol for assessing PAK6 levels in a commonly used neuronal cell line, PC-12. In comparison with other methodology, this approach (1) does not require ex-planted tissue to identify PAK6 in neurons and (2) unlike other protocols which require steroid depleted media for detection of PAK6 in non-neuronal cell lines, such as prostate cancer cell lines, we were easily able to detect PAK6 in PC-12 cells grown in complete, steroid-containing media. Thus the present protocol allows for the efficient detection of native PAK6 in PC-12 cells to expedite targeted basic research of the emerging importance of PAK6 function in the brain as well as to accelerate the identification and isolation of potential therapeutic targets not only in cancerous but brain disease states as well.

Genetically Epilepsy-Prone Rats Display Anxiety-Like Behaviors and Neuropsychiatric Comorbidities of Epilepsy

Epilepsy is associated with a variety of neuropsychiatric comorbidities, including both anxiety and depression. Despite high occurrences of depression and anxiety seen in human epilepsy populations, little is known about the etiology of these comorbidities. Experimental models of epilepsy provide a platform to disentangle the contribution of acute seizures, genetic predisposition, and underlying circuit pathologies to anxious and depressive phenotypes. Most studies to date have focused on comorbidities in acquired epilepsies; genetic models, however, allow for the assessment of affective phenotypes that occur prior to onset of recurrent seizures. Here, we tested male and female genetically epilepsy-prone rats (GEPR-3s) and Sprague-Dawley controls in a battery of tests sensitive to anxiety-like and depressive-like phenotypes. GEPR-3s showed increased anxiety-like behavior in the open field test, elevated plus maze, light-dark transition test, and looming threat test. Moreover, GEPR-3s showed impaired prepulse inhibition of the acoustic startle reflex, decreased sucrose preference index, and impaired novel object recognition memory. We also characterized defense behaviors in response to stimulation thresholds of deep and intermediate layers of the superior colliculus (DLSC), but found no difference between strains. In sum, GEPR-3s showed inherited anxiety, an effect that did not differ significantly between sexes. The anxiety phenotype in adult GEPR-3s suggests strong genetic influences that may underlie both the seizure disorder and the comorbidities seen in epilepsy.

Comorbid epilepsy in autism spectrum disorder: Implications of postnatal inflammation for brain excitability

OBJECTIVE

In different cohorts, 5%-30% of individuals with autism spectrum disorder (ASD) also have epilepsy. The high co-occurrence of these disorders suggests that a common mechanistic link may exist. The underlying pathophysiology of this comorbidity remains unknown. To investigate the mechanism(s) involved in the pathogenesis of ASD and epilepsy, we developed and validated a novel mouse model that concurrently exhibits hallmark features of both disorders.

METHODS

We utilized inbred BTBR T+ Itpr3tf/J (BTBR) mice that exhibit the core behavioral characteristics of ASD (ie, impaired sociability, altered vocalizations, and restricted interests). BTBR mice received a lipopolysaccharide (LPS) or sterile saline injection at postnatal day (P)7, P14, or P21. Cytokine expression was analyzed for interleukin (IL)-1β, IL-10, IL-6, and tumor necrosis factor α in brain tissue of P7 and adult BTBR mice. Adult BTBR mice were behaviorally analyzed for seizure susceptibility, sociability, communication deficits, and motor stereotypies, and monitored using chronic video-electroencephalography (EEG).

RESULTS

Adult male and female BTBR mice treated at P7-P14 with LPS were more sensitive to pentylenetetrazol-induced seizures than saline-treated controls. ASD-like behaviors and hippocampal cytokine levels were unchanged between P7 LPS-treated BTBR mice and controls. EEG recordings from the dorsal hippocampus revealed a significant increase in number and frequency of seizures over the 4-week recording period (P60-P88) in BTBR mice postnatally treated with LPS at P7. These results indicate the presence of a comorbid epileptic phenotype in BTBR mice.

SIGNIFICANCE

These findings suggest that an early postnatal immune challenge can increase brain excitability in adult BTBR mice and reveal an underlying epilepsy phenotype. This novel animal model may enable the elucidation of specific molecular alterations that are associated with the concurrent presentation of ASD and epilepsy, which could facilitate the development of targeted therapies for individuals affected by this comorbidity.

Time and sex dependent effects of magnesium sulphate on post-asphyxial seizures in preterm fetal sheep

KEY POINTS

We evaluated the effect of magnesium sulphate (MgSO₄ ) on seizures induced by asphyxia in preterm fetal sheep. MgSO₄ did not prevent seizures, but significantly reduced the total duration, number of seizures, seizure amplitude and average seizure burden. Saline-asphyxia male fetuses had significantly more seizures than female fetuses, but male fetuses showed significantly greater reduction in seizures during MgSO₄ infusion than female fetuses. A circadian profile of seizure activity was observed in all fetuses, with peak seizures seen around 04.00-06.00 h on the first and second days after the end of asphyxia. This study is the first to demonstrate that MgSO₄ has utility as an anti-seizure agent after hypoxia-ischaemia. More information is needed about the mechanisms mediating the effect of MgSO₄ on seizures and sexual dimorphism, and the influence of circadian rhythms on seizure expression.

ABSTRACT

Seizures are common in newborns after asphyxia at birth and are often refractory to anti-seizure agents. Magnesium sulphate (MgSO₄ ) has anticonvulsant effects and is increasingly given to women in preterm labour for potential neuroprotection. There is limited information on its effects on perinatal seizures. We examined the hypothesis that MgSO₄ infusion would reduce fetal seizures after asphyxia in utero. Preterm fetal sheep at 0.7 gestation (104 days, term = 147 days) were given intravenous infusions of either saline (n = 14) or MgSO₄ (n = 12, 160 mg bolus + 48 mg h^-1 infusion over 48 h). Fetuses underwent umbilical cord occlusion (UCO) for 25 min, 24 h after the start of infusion. The start time for seizures did not differ between groups, but MgSO₄ significantly reduced the total number of seizures (P < 0.001), peak seizure amplitude (P < 0.05) and seizure burden (P < 0.005). Within the saline-asphyxia group, male fetuses had significantly more seizures than females (P < 0.05). Within the MgSO₄ -asphyxia group, although both sexes had fewer seizures than the saline-asphyxia group, the greatest effect of MgSO₄ was on male fetuses, with reduced numbers of seizures (P < 0.001) and seizure burden (P < 0.005). Only 1 out of 6 MgSO₄ males had seizures on the second day post-UCO compared to 5 out of 6 MgSO₄ female fetuses (P = 0.08). Finally, seizures showed a circadian profile with peak seizures between 04.00 and 06.00 h on the first and second day post-UCO. Collectively, these results suggest that MgSO₄ may have utility in treating perinatal seizures and has sexually dimorphic effects.

Effect of atorvastatin on behavioral alterations and neuroinflammation during epileptogenesis

Temporal lobe epilepsy (TLE) is the most frequent and medically refractory type of epilepsy in humans. In addition to seizures, patients with TLE suffer from behavioral alterations and cognitive deficits. Poststatus epilepticus model of TLE induced by pilocarpine in rodents has enhanced the understanding of the processes leading to epilepsy and thus, of potential targets for antiepileptogenic therapies. Clinical and experimental evidence suggests that inflammatory processes in the brain may critically contribute to epileptogenesis. Statins are inhibitors of cholesterol synthesis, and present pleiotropic effects that include antiinflammatory properties. We aimed the present study to test the hypothesis that atorvastatin prevents behavioral alterations and proinflammatory state in the early period after pilocarpine-induced status epilepticus. Male and female C57BL/6 mice were subjected to status epilepticus induced by pilocarpine and treated with atorvastatin (10 or 100mg/kg) for 14days. Atorvastatin slightly improved the performance of mice in the open-field and object recognition tests. In addition, atorvastatin dose-dependently decreased basal and status epilepticus-induced levels of interleukin-1β (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interferon-γ (INF-γ) and increased interleukin-10 (IL-10) levels in the hippocampus and cerebral cortex. The antiinflammatory effects of atorvastatin were qualitatively identical in both sexes. Altogether, these findings extend the range of beneficial actions of atorvastatin and indicate that its antiinflammatory effects may be useful after an epileptogenic insult.

Characteristics and Health Needs of Veterans in Jails and Prisons: What We Know and Do Not Know about Incarcerated Women Veterans

PURPOSE

The majority of U.S. veterans in prisons and local jails are men, but incarcerated women veterans remain an important and understudied group.

METHODS

This study reported differences in sociodemographic, health, and criminal justice characteristics using Veterans Affairs (VA) administrative data on a national sample of 30,964 incarcerated veterans (30,440 men and 524 women) who received outreach from the VA Health Care for Reentry Veterans program between 2007 and 2011. Descriptive statistics and multivariable logistic regressions determined gender and racial differences in this population.

RESULTS

Compared with incarcerated veterans who were men, incarcerated women veterans were younger (d = 0.68), had significantly lower lifetime arrests (AOR, 0.65; p < .001; 99% CI, 0.49-0.87), and were less likely to have been incarcerated for a violent offense (AOR, 0.47; p < .001; 99% CI, 0.35-0.63). Notably, 58% of women were of reproductive age. Women were more likely to have reported eye problems, hypertension, chronic obstructive pulmonary disease, and seizure disorder, and were more likely to receive a preliminary diagnosis of mood disorder than men. Women were more likely to have received VA benefits, used VA health care before, and be willing to use VA services after release. A few important differences emerged when stratified by race.

CONCLUSIONS

These findings suggest that incarcerated women veterans are interested in VA health care services, but there is lack of information about women's health needs through the Health Care for Reentry Veterans program. The inclusion of Health Care for Reentry Veterans screening questions about women's health issues may support the VA's interests to better engage women veterans in care.

Genetic and Molecular Regulation of Extrasynaptic GABA-A Receptors in the Brain: Therapeutic Insights for Epilepsy

GABA-A receptors play a pivotal role in many brain diseases. Epilepsy is caused by acquired conditions and genetic defects in GABA receptor channels regulating neuronal excitability in the brain. The latter is referred to as GABA channelopathies. In the last two decades, major advances have been made in the genetics of epilepsy. The presence of specific GABAergic genetic abnormalities leading to some of the classic epileptic syndromes has been identified. Advances in molecular cloning and recombinant systems have helped characterize mutations in GABA-A receptor subunit genes in clinical neurology. GABA-A receptors are the prime targets for neurosteroids (NSs). However, GABA-A receptors are not static but undergo rapid changes in their number or composition in response to the neuroendocrine milieu. This review describes the recent advances in the genetic and neuroendocrine control of extrasynaptic and synaptic GABA-A receptors in epilepsy and its impact on neurologic conditions. It highlights the current knowledge of GABA genetics in epilepsy, with an emphasis on the neuroendocrine regulation of extrasynaptic GABA-A receptors in network excitability and seizure susceptibility. Recent advances in molecular regulation of extrasynaptic GABA-A receptor-mediated tonic inhibition are providing unique new therapeutic approaches for epilepsy, status epilepticus, and certain brain disorders. The discovery of an extrasynaptic molecular mechanism represents a milestone for developing novel therapies such as NS replacement therapy for catamenial epilepsy.

PTEN deletion increases hippocampal granule cell excitability in male and female mice

Deletion of the mTOR pathway inhibitor PTEN from postnatally-generated hippocampal dentate granule cells causes epilepsy. Here, we conducted field potential, whole cell recording and single cell morphology studies to begin to elucidate the mechanisms by which granule cell-specific PTEN-loss produces disease. Cells from both male and female mice were recorded to identify sex-specific effects. PTEN knockout granule cells showed altered intrinsic excitability, evident as a tendency to fire in bursts. PTEN knockout granule cells also exhibited increased frequency of spontaneous excitatory synaptic currents (sEPSCs) and decreased frequency of inhibitory currents (sIPSCs), further indicative of a shift towards hyperexcitability. Morphological studies of PTEN knockout granule cells revealed larger dendritic trees, more dendritic branches and an impairment of dendrite self-avoidance. Finally, cells from both female control and female knockout mice received more sEPSCs and more sIPSCs than corresponding male cells. Despite the difference, the net effect produced statistically equivalent EPSC/IPSC ratios. Consistent with this latter observation, extracellularly evoked responses in hippocampal slices were similar between male and female knockouts. Both groups of knockouts were abnormal relative to controls. Together, these studies reveal a host of physiological and morphological changes among PTEN knockout cells likely to underlie epileptogenic activity.

SIGNIFICANCE STATEMENT

Hyperactivation of the mTOR pathway is associated with numerous neurological diseases, including autism and epilepsy. Here, we demonstrate that deletion of the mTOR negative regulator, PTEN, from a subset of hippocampal dentate granule impairs dendritic patterning, increases excitatory input and decreases inhibitory input. We further demonstrate that while granule cells from female mice receive more excitatory and inhibitory input than males, PTEN deletion produces mostly similar changes in both sexes. Together, these studies provide new insights into how the relatively small number (≈200,000) of PTEN knockout granule cells instigates the development of the profound epilepsy syndrome evident in both male and female animals in this model.

Subtle improvement of seizure susceptibility by atorvastatin treatment during epileptogenesis

BACKGROUND

The process by which a brain insult elicits epilepsy is termed epileptogenesis and it is characterized by numerous molecular and functional alterations. Statins are first-line drugs for hypercholesterolemia and related diseases, and display neuroprotective properties in clinical and experimental studies. Considering the importance in developing therapeutic strategies to prevent or modify epileptogenesis, we aimed the present study to test the hypothesis that atorvastatin modifies seizure susceptibility of mice after status epilepticus (SE).

METHODS

Male and female C57BL/6 mice were submitted to the pilocarpine-induced SE and then treated with atorvastatin (10 or 100mg/kg, once daily by gavage) for 14days. At days 7 and 14 post SE we evaluated the susceptibility of mice to the convulsant effects of a low dose of PTZ (30mg/kg). Cell loss in the hilus of dentate gyrus was evaluated by Giemsa staining.

RESULTS

Latencies to myoclonic jerks and to tonic-clonic seizures decreased between baseline (before SE) and days 7 and 14 after SE, confirming the development of seizure susceptibility. Atorvastatin protected against PTZ-induced tonic-clonic seizures in both sexes at day 14 post-SE. Protective effects were similar in both female and male mice, except that a high dose of atorvastatin was required for females (protection at 100mg/kg versus 10mg/kg in males). Giemsa staining did not reveal neuroprotective effects of atorvastatin.

CONCLUSIONS

Atorvastatin treatment during epileptogenesis had slight beneficial effects on seizure susceptibility. These seem not related to neuroprotection. Further studies are needed to determine the disease-modifying potential of atorvastatin in epilepsy.