Epileptogenesis and drug-resistant in focal cortical dysplasias: Update on clinical, cellular, and molecular markers.

Focal cortical dysplasia (FCD) is a cortical malformation in brain development and is considered as one of the major causes of drug-resistant epilepsiesin children and adults. The pathogenesis of FCD is yet to be fully understood. Imaging markers such as MRI are currently the surgeons major obstacle due to the difficulty in delimiting the precise dysplasic area and a mosaic brain where there is epileptogenic tissue invisible to MRI. Also increased gene expression and activity may be responsible for the alterations in cell proliferation, migration, growth, and survival. Altered expressions were found, particularly in the PI3K/AKT/mTOR pathway. Surgery is still considered the most effective treatment option, due to drug-resistance, and up to 60 % of patients experience complete seizure control, varying according to the type and location of FCD. Both genetic and epigenetic factors may be involved in the pathogenesis of FCD, and there is no conclusive evidence whether these alterations are inherited or have an environmental origin.

Short-term consumption of highly processed diets varying in macronutrient content impair the sense of smell and brain metabolism in mice.

OBJECTIVE: Food processing greatly contributed to increased food safety, diversity, and accessibility. However, the prevalence of highly palatable and highly processed food in our modern diet has exacerbated obesity rates and contributed to a global health crisis. While accumulating evidence suggests that chronic consumption of such foods is detrimental to sensory and neural physiology, it is unclear whether its short-term intake has adverse effects. Here, we assessed how short-term consumption (<2 months) of three diets varying in composition and macronutrient content influence olfaction and brain metabolism in mice. METHODS: The diets tested included a grain-based standard chow diet (CHOW; 54% carbohydrate, 32% protein, 14% fat; #8604 Teklad Rodent diet , Envigo Inc.), a highly processed control diet (hpCTR; 70% carbohydrate, 20% protein, 10% fat; #D12450B, Research Diets Inc.), and a highly processed high-fat diet (hpHFD; 20% carbohydrate, 20% protein, 60% fat; #D12492, Research Diets Inc.). We performed behavioral and metabolic phenotyping, electro-olfactogram (EOG) recordings, brain glucose metabolism imaging, and mitochondrial respirometry in different brain regions. We also performed RNA-sequencing (RNA-seq) in the nose and across several brain regions, and conducted differential expression analysis, gene ontology, and network analysis. RESULTS: We show that short-term consumption of the two highly processed diets, but not the grain-based diet, regardless of macronutrient content, adversely affects odor-guided behaviors, physiological responses to odorants, transcriptional profiles in the olfactory mucosa and brain regions, and brain glucose metabolism and mitochondrial respiration. CONCLUSIONS: Even short periods of highly processed food consumption are sufficient to cause early olfactory and brain abnormalities, which has the potential to alter food choices and influence the risk of developing metabolic disease.

A behavioral economic risk aversion experiment in the context of the COVID-19 pandemic.

We investigated what degree of risk of infection with COVID-19 is necessary so that people intend to stay home, even when doing so means losing their salary. We conducted an online survey across Brazil during the initial outbreak, in which 8,345 participants answered a questionnaire designed to identify the maximum tolerated risk (k') necessary for them to disregard social distancing recommendations and guarantee their salaries. Generalized linear mixed models, path analysis structural equation, and conditional interference classification tree were performed to further understand how sociodemographic factors impact k' and to establish a predictive model for the risk behavior of leaving home during the pandemic. We found that, on average, people tolerate 38% risk of infection to leave home and earn a full salary, but this number decreased to 13% when the individual risk perception of becoming ill from severe acute respiratory syndrome coronavirus-2 is considered. Furthermore, participants who have a medium-to-high household income and who are older than 35 years are more likely to be part of the risk-taking group who leave home regardless of the potential COVID-19 infection level; while participants over 45 years old and with good financial health are more likely to be part of the risk-averse group, who stay home at the expense of any salary offered. Our findings add to the political and public debate concerning lockdown strategies by showing that, contrary to supposition, people with low socioeconomic status are not more likely to ignore social distancing recommendations due to personal economic matters.

Drebrin expression patterns in patients with refractory temporal lobe epilepsy and hippocampal sclerosis.

OBJECTIVE: Drebrins are crucial for synaptic function and dendritic spine development, remodeling, and maintenance. In temporal lobe epilepsy (TLE) patients, a significant hippocampal synaptic reorganization occurs, and synaptic reorganization has been associated with hippocampal hyperexcitability. This study aimed to evaluate, in TLE patients, the hippocampal expression of drebrin using immunohistochemistry with DAS2 or M2F6 antibodies that recognize adult (drebrin A) or adult and embryonic (pan-drebrin) isoforms, respectively. METHODS: Hippocampal sections from drug-resistant TLE patients with hippocampal sclerosis (HS; TLE, n = 33), of whom 31 presented with type 1 HS and two with type 2 HS, and autopsy control cases (n = 20) were assayed by immunohistochemistry and evaluated for neuron density, and drebrin A and pan-drebrin expression. Double-labeling immunofluorescences were performed to localize drebrin A-positive spines in dendrites (MAP2), and to evaluate whether drebrin colocalizes with inhibitory (GAD65) and excitatory (VGlut1) presynaptic markers. RESULTS: Compared to controls, TLE patients had increased pan-drebrin in all hippocampal subfields and increased drebrin A-immunopositive area in all hippocampal subfields but CA1. Drebrin-positive spine density followed the same pattern as total drebrin quantification. Confocal microscopy indicated juxtaposition of drebrin-positive spines with VGlut1-positive puncta, but not with GAD65-positive puncta. Drebrin expression in the dentate gyrus of TLE cases was associated negatively with seizure frequency and positively with verbal memory. TLE patients with lower drebrin-immunopositive area in inner molecular layer (IML) than in outer molecular layer (OML) had a lower seizure frequency than those with higher or comparable drebrin-immunopositive area in IML compared with OML. SIGNIFICANCE: Our results suggest that changes in drebrin-positive spines and drebrin expression in the dentate gyrus of TLE patients are associated with lower seizure frequency, more preserved verbal memory, and a better postsurgical outcome.

Review of neuroimaging findings in congenital Zika virus syndrome and its relation to the time of infection.

BACKGROUND: Many original articles and case series have been published emphasizing the neuroimaging findings of congenital Zika virus (ZIKV) infection. The majority of these studies do not follow a neuroradiological methodology to describe malformations and brain abnormalities resulting from ZIKV infection. The cause-and-effect correlation between the gestational period of maternal infection and the severity of encephalic changes at birth has rarely been reported. A systematic literature review was conducted on the neuroimaging findings in children affected with microcephaly due to ZIKV. METHODS: PubMed, Cochrane Library and Web of Science were searched for full-text articles published up to July 2019. Duplicate entries were removed. Two independent reviewers performed a quality assessment of all the studies included. RESULTS: A total of 2214 publications were identified. Of these 2170 were excluded by analysis of titles and abstracts, resulting in the inclusion of only eight articles. Chi-square and Fisher's exact tests were performed with a 95% confidence interval to verify the statistically significant differences in the neuroradiological findings between the cases of ZIKV infection in the first or second trimester of gestation. The studies published so far have described image abnormalities at random, without utilizing any pre-established neuroradiological criteria, and imaging modalities with different sensitivity and accuracy have been used, which jeopardizes a reliable and adequate statistical analysis. CONCLUSIONS: Neuroimaging abnormalities are much more prevalent and severe when the infection by ZIKV is contracted in the first or second trimester of pregnancy.

Nociceptin/orphanin FQ receptor modulates painful and fatigue symptoms in a mouse model of fibromyalgia.

Generalized pain and fatigue are both hallmarks of fibromyalgia, a syndrome with an indefinite etiology. The treatment options for fibromyalgia are currently limited, probably because of its intricate pathophysiology. Thus, further basic and clinical research on this condition is currently needed. This study investigated the effects of nociceptin/orphanin FQ (N/OFQ) receptor (NOPr) ligands and the modulation of the NOP system in the preclinical mouse model of reserpine-induced fibromyalgia. The effects of administration of the natural agonist N/OFQ and the selective NOPr antagonists (UFP-101 and SB-612111) were evaluated in fibromyalgia-related symptoms in reserpine-treated mice. The expression of prepronociceptin/orphanin FQ and NOPr was assessed in central and peripheral sites at different time points after reserpine administration. Nociceptin/orphanin FQ displayed dual effects in the behavioral changes in the reserpine-elicited fibromyalgia model. The peptide NOPr antagonist UFP-101 produced analgesic and antifatigue effects, by preventing alterations in brain activity and skeletal muscle metabolism, secondary to fibromyalgia induction. The nonpeptide NOPr antagonist SB-612111 mirrored the favorable effects of UFP-101 in painful and fatigue alterations induced by reserpine. A time-related up- or downregulation of prepronociceptin/orphanin FQ and NOPr was observed in supraspinal, spinal, and peripheral sites of reserpine-treated mice. Our data shed new lights on the mechanisms underlying the fibromyalgia pathogenesis, supporting a role for N/OFQ-NOP receptor system in this syndrome.

Ketamine promotes increased freezing behavior in rats with experimental PTSD without changing brain glucose metabolism or BDNF.

Acute treatment with ketamine, an NMDA receptor antagonist, has been reported to be efficacious in treating depression. The goal of our study was to evaluate ketamine treatment in an animal model of another important psychiatric disease, post-traumatic stress disorder (PTSD). Fifty-eight male rats were initially divided into four groups: Control+Saline (CTRL+SAL), Control+Ketamine (CTRL+KET), PTSD+Saline (PTSD+SAL) and PTSD+Ketamine (PTSD+KET). To mimic PTSD we employed the inescapable footshock protocol. The PTSD animals were classified according to freezing behavior duration into "extreme behavioral response" (EBR) or "minimal behavioral response" (MBR). Afterwards, the glucose metabolism and BDNF were evaluated in the hippocampus, frontal cortex, and amygdala. Our results show that animals classified as EBR exhibited increased freezing behavior and that ketamine treatment further increased freezing duration. Glucose metabolism and BDNF levels showed no significant differences. These results suggest ketamine might aggravate PTSD symptoms and that this effect is unrelated to alterations in glucose metabolism or BDNF protein levels.

Cardioembolic sources in stroke patients in South of Brazil.

Background. Stroke is a leading cause of mortality and disability in Brazil and around the world. Cardioembolism is responsible for nearly 30% of the origins of ischemic stroke. Methods. We analyzed data of 256 patients with cardioembolic ischemic stroke (according to TOAST classification) who were admitted into the Hospital São Lucas-PUCRS from October 2011 to January 2014. The cardioembolic subtype was divided into six subgroups: arrhythmias, valvular heart disease, coronary artery disease, cardiomyopathy, septal abnormalities, and intracardiac injuries. The prevalence of the most important cardiovascular risk factors and medications in use for prevention of systemic embolism by the time of hospital admission was analyzed in each patient. Results. Among 256 patients aged 60.2 +/- 6.9 years, 132 males, arrhythmias were the most common cause of cardioembolism corresponding to 50.7%, followed by valvular heart disease (17.5%) and coronary artery disease (16%). Hypertension (61.7%) and dyslipidemia (43.7%) were the most common risk factors. Less than 50% of patients with arrhythmias were using oral anticoagulants. Conclusions. Identifying the prevalence of cardioembolic stroke sources subgroups has become an increasingly important role since the introduction of new oral anticoagulants. In this study, arrhythmias (especially atrial fibrillation) were the main cause of cardioembolism.

An 18-year follow-up of seizure outcome after surgery for temporal lobe epilepsy and hippocampal sclerosis.

OBJECTIVES: To evaluate the very long-term clinical outcome of surgery for mesial temporal lobe epilepsy and unilateral hippocampal sclerosis (MTLE/HS) without atypical features. The impact of surgical technique and postoperative reduction of medication on this outcome was investigated. DESIGN: Prospective longitudinal cohort follow-up study for up to18 years. SETTING: Epilepsy surgery centre in a university hospital. PATIENTS: 108 patients who underwent unilateral MTLE/HS. INTERVENTION: Surgery for MTLE/HS. MAIN OUTCOME MEASURE: Engel classification (I). Clinical evaluations were based on systematic interviews in person or by phone. Kaplan-Maier survival curves estimated the probability of remaining seizure free. The impact of medication management in the postoperative outcome was analysed using Cox regression. RESULTS: The probability of remaining completely seizure-free at 12 and 18 years after MTLE/HS surgery was 65% and 62%, respectively. The risk of having any recurrence was 22% during the first 24 months and increased 1.4% per year afterwards. Type of surgical technique (selective amygdalohippocampectomy vs anterior temporal lobectomy) did not impact on outcome. Remaining on antiepileptic drugs and history of generalised clonic seizure diminished the probability of remaining seizure free. CONCLUSIONS: MTLE/HS surgery is able to keep patients seizure free for almost up to two decades. Removal of the neocortex besides the mesial portion of the temporal lobe does not lead to better chances of seizure control. These findings are applicable to the typical unilateral MTLE/HS syndrome and cannot be generalised for all types of TLE. Future longitudinal randomised controlled studies are needed to replicate these findings.

A new spatial orientation memory test: Evaluation in patients with mild Alzheimer’s disease and in patients with operated and unoperated mesial temporal lobe epilepsy

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Background and objectives: Spatial orientation and spatial learning depend on the medial temporal lobe. A new test of spatial memory in humans is described, and applied to patients with Alzheimer’s disease (AD), with presumable damage of that region, and to patients with unilateral mesial temporal sclerosis (MTS) submitted or not to treatment by selective surgical amygdala-hippocampectomy (SAH).Methods: Subjects were asked to go to each of four objects hanging from the wall of a room: a cylinder, a square, a ball and a triangle (trial 1). In trial 2 they repeated this blindfolded; all figures except the cylinder were removed; once the subjects reached the cylinder they had to say what figures should be at the left, right and back. In trial 3, all figures were withdrawn and the subjects, again blindfolded, were instructed first to go to the front, right, left and back, and then to go to the former positions occupied by the cylinder, the ball, the square and the triangle. Results: Experiment 1 studied 10 patients with mild AD and 10 controls matched by age, gender and schooling. Performance was 46% lower in AD patients relative to controls (p <0.001). Experiment 2 studied 23 patients with MTS, 20 patients submitted to SAH, and 23 healthy volunteers with similar levels of age, gender and schooling. No differences in performance among these three groups were observed. Conclusions: The test distinguished performance deficits of AD patients relative to controls, but not among MTS and STH patients and controls

Antiepileptic effect of acylpolyaminetoxin JSTX-3 on rat hippocampal CA1 neurons in vitro.

The Joro spider toxin (JSTX-3), derived from Nephila clavata, has been found to block glutamate excitatory activity. Epilepsy has been studied in vitro, mostly on rat hippocampus, through brain slices techniques. The aim of this study is to verify the effect of the JSTX-3 on the epileptiform activity induced by magnesium-free medium in rat CA1 hippocampal neurons. Experiments were performed on hippocampus slices of control and pilocarpine-treated Wistar rats, prepared and maintained in vitro. Epileptiform activity was induced through omission of magnesium from the artificial cerebrospinal fluid (0-Mg2+ ACSF) superfusate and iontophoretic application of N-methyl-D-aspartate (NMDA). Intracellular recordings were obtained from CA1 pyramidal neurons both of control and epileptic rats. Passive membrane properties were analyzed before and after perfusion with the 0-Mg2+ ACSF and the application of toxin JSTX-3. During the ictal-like activity, the toxin JSTX-3 was applied by pressure ejection, abolishing this activity. This effect was completely reversed during the washout period when the slices were formerly perfused with artificial cerebrospinal fluid (ACSF) and again with 0-Mg2+ ACSF. Our results suggest that the toxin JSTX-3 is a potent blocker of induced epileptiform activity.

Sleep organization in children with partial refractory epilepsy.

Although it is currently known that sleep can influence epilepsy and epilepsy can influence sleep organization, few data have been published on this mutual interaction concerning the pediatric population. The objective of this study was to verify the eventual presence of sleep alterations in children with partial refractory epilepsy. Seventeen patients with partial refractory epilepsy were submitted to whole-night polysomnography as part of their epilepsy investigation. Polysomnographic recordings were performed on a digital video-electroencephalography (EEG) system and consisted of the registration of EEG (24 channels), electro-oculogram, electromyogram, electrocardiogram, and nasal airflow and abdominal respiratory movements. Sleep stages were visually scored following standard criteria, and ictal events were classified according to the international classification of seizures. The patients were also subdivided into two subgroups based on the presence or absence of ictal episodes during the recording night. The results concerning sleep organization were compared with those obtained from a normal control group. The analysis of the sleep parameters showed a reduction of total time in bed and total sleep time in both subgroups of epileptic children; there was a higher number of stage shifts per hour in the control group than in both epileptic subgroups. The percentage of stage 2 shifts is significantly reduced in patients with epilepsy and seizures during the night and the percentage of stage 3 to 4 shifts is increased. Nonsignificant differences are evident for the number of awakenings per hour and the percentage of stage 1 shifts. The percentage of rapid eye movement (REM) sleep is reduced, and first REM latency is increased in both epileptic subgroups, compared with normal controls, without statistical significance. Nine of 17 patients had seizures during the polysomnographic recording; nocturnal ictal events occurred mostly during non-REM sleep stage 2. Our results show that patients with partial refractory epilepsies have only mild sleep structure abnormalities, and this can be considered as an effect of the epileptic syndrome per se or as a result of the chronic antiepilepsy drug treatment.

Subcortical band heterotopia (SBH) in males: clinical, imaging and genetic findings in comparison with females.

Subcortical band heterotopia (SBH) or double cortex syndrome is a neuronal migration disorder, which occurs very rarely in males: to date, at least 110 females but only 11 in males have been reported. The syndrome is usually associated with mutations in the doublecortin (DCX) (Xq22.3-q23) gene, and much less frequently in the LIS1 (17p13.3) gene. To determine whether the phenotypic spectrum, the genetic basis and genotype-phenotype correlations of SBH in males are similar to those in females, we compared the clinical, imaging and molecular features in 30 personally evaluated males and 60 previously reported females with SBH. Based on the MRI findings, we defined the following band subtypes: partial, involving one or two cerebral lobes; intermediate, involving two lobes and a portion of a third; diffuse, with substantial involvement of three or more lobes; and pachygyria-SBH, in which posterior SBH merges with anterior pachygyria. Karyo typing and mutation analysis of DCX and/or LIS1 were performed in 23 and 24 patients, respectively. The range of clinical phenotypes in males with SBH greatly overlapped that in females. MRI studies revealed that some anatomical subtypes of SBH, such as partial and intermediate posterior, pachygyria-SBH and diffuse bands with posterior predominance, were more frequently or exclusively present in males. Conversely, classical diffuse SBH and diffuse bands with anterior predominance were more frequent in females. Males had either mild or the most severe band subtypes, and these correlated with the over-representation of normal/borderline intelligence and severe mental retardation, respectively. Conversely, females who had predominantly diffuse bands exhibited mostly mild or moderate mental retardation. Seven patients (29%) had missense mutations in DCX; in four, these were germline mutations, whereas in three there was evidence for somatic mosaicism. A germline missense mutation of LIS1 and a partial trisomy of chromosome 9p were identified in one patient (4%) each. One male each had a possible pathogenic intronic base change in both DCX and LIS1 genes. Our study shows that SBH in males is a clinically heterogeneous syndrome, mostly occurring sporadically. The clinical spectrum is similar to that of females with SBH. However, the greater cognitive and neuroradiological heterogeneity and the small number of mutations identified to date in the coding sequences of the DCX and LIS1 genes in males differ from the findings in females. This suggests other genetic mechanisms such as mutations in the non-coding regions of the DCX or LIS1 genes, gonadal or somatic mosaicism, and finally mutations of other genes.