Dysfunctional hippocampal-prefrontal network underlies a multidimensional neuropsychiatric phenotype following early-life seizure.

Brain disturbances during development can have a lasting impact on neural function and behavior. Seizures during this critical period are linked to significant long-term consequences such as neurodevelopmental disorders, cognitive impairments, and psychiatric symptoms, resulting in a complex spectrum of multimorbidity. The hippocampus-prefrontal cortex (HPC-PFC) circuit emerges as a potential common link between such disorders. However, the mechanisms underlying these outcomes and how they relate to specific behavioral alterations are unclear. We hypothesized that specific dysfunctions of hippocampal-cortical communication due to early-life seizure would be associated with distinct behavioral alterations observed in adulthood. Here, we performed a multilevel study to investigate behavioral, electrophysiological, histopathological, and neurochemical long-term consequences of early-life Status epilepticus in male rats. We show that adult animals submitted to early-life seizure (ELS) present working memory impairments and sensorimotor disturbances, such as hyperlocomotion, poor sensorimotor gating, and sensitivity to psychostimulants despite not exhibiting neuronal loss. Surprisingly, cognitive deficits were linked to an aberrant increase in the HPC-PFC long-term potentiation (LTP) in a U-shaped manner, while sensorimotor alterations were associated with heightened neuroinflammation, as verified by glial fibrillary acidic protein (GFAP) expression, and altered dopamine neurotransmission. Furthermore, ELS rats displayed impaired HPC-PFC theta-gamma coordination and an abnormal brain state during active behavior resembling rapid eye movement (REM) sleep oscillatory dynamics. Our results point to impaired HPC-PFC functional connectivity as a possible pathophysiological mechanism by which ELS can cause cognitive deficits and psychiatric-like manifestations even without neuronal loss, bearing translational implications for understanding the spectrum of multidimensional developmental disorders linked to early-life seizures.

Identifying cellular markers of focal cortical dysplasia type II with cell-type deconvolution and single-cell signatures.

Focal cortical dysplasia (FCD) is a brain malformation that causes medically refractory epilepsy. FCD is classified into three categories based on structural and cellular abnormalities, with FCD type II being the most common and characterized by disrupted organization of the cortex and abnormal neuronal development. In this study, we employed cell-type deconvolution and single-cell signatures to analyze bulk RNA-seq from multiple transcriptomic studies, aiming to characterize the cellular composition of brain lesions in patients with FCD IIa and IIb subtypes. Our deconvolution analyses revealed specific cellular changes in FCD IIb, including neuronal loss and an increase in reactive astrocytes (astrogliosis) when compared to FCD IIa. Astrogliosis in FCD IIb was further supported by a gene signature analysis and histologically confirmed by glial fibrillary acidic protein (GFAP) immunostaining. Overall, our findings demonstrate that FCD II subtypes exhibit differential neuronal and glial compositions, with astrogliosis emerging as a hallmark of FCD IIb. These observations, validated in independent patient cohorts and confirmed using immunohistochemistry, offer novel insights into the involvement of glial cells in FCD type II pathophysiology and may contribute to the development of targeted therapies for this condition.

An Overview of Animal Models Related to Schizophrenia.

Schizophrenia is a heterogeneous psychiatric disorder that is poorly treated with current therapies. In this brief review, we provide an update regarding the use of animal models to study schizophrenia in an attempt to understand its aetiology and develop novel therapeutic strategies. Tremendous progress has been made developing and validating rodent models that replicate the aetiologies, brain pathologies, and behavioural abnormalities associated with schizophrenia in humans. Here, models are grouped into 3 categories-developmental, drug induced, and genetic-to reflect the heterogeneous risk factors associated with schizophrenia. Each of these models is associated with varied but overlapping pathophysiology, endophenotypes, behavioural abnormalities, and cognitive impairments. Studying schizophrenia using multiple models will permit an understanding of the core features of the disease, thereby facilitating preclinical research aimed at the development and validation of better pharmacotherapies to alter the progression of schizophrenia or alleviate its debilitating symptoms.

Manual Hippocampal Subfield Segmentation Using High-Field MRI: Impact of Different Subfields in Hippocampal Volume Loss of Temporal Lobe Epilepsy Patients.

In patients with temporal lobe epilepsy (TLE), presurgical magnetic resonance imaging (MRI) often reveals hippocampal atrophy, while neuropathological assessment indicates the different types of hippocampal sclerosis (HS). Different HS types are not discriminated in MRI so far. We aimed to define the volume of each hippocampal subfield on MRI manually and to compare automatic and manual segmentations for the discrimination of HS types. The T2-weighted images from 14 formalin-fixed age-matched control hippocampi were obtained with 4.7T MRI to evaluate the volume of each subfield at the anatomical level of the hippocampal head, body, and tail. Formalin-fixed coronal sections at the level of the body of 14 control cases, as well as tissue samples from 24 TLE patients, were imaged with a similar high-resolution sequence at 3T. Presurgical three-dimensional (3D) T1-weighted images from TLE went through a FreeSurfer 6.0 hippocampal subfield automatic assessment. The manual delineation with the 4.7T MRI was identified using Luxol Fast Blue stained 10-µm-thin microscopy slides, collected at every millimeter. An additional section at the level of the body from controls and TLE cases was submitted to NeuN immunohistochemistry for neuronal density estimation. All TLE cases were classified according to the International League Against Epilepsy's (ILAE's) HS classification. Manual volumetry in controls revealed that the dentate gyrus (DG)+CA4 region, CA1, and subiculum accounted for almost 90% of the hippocampal volume. The manual 3T volumetry showed that all TLE patients with type 1 HS (TLE-HS1) had lower volumes for DG+CA4, CA2, and CA1, whereas those TLE patients with HS type 2 (TLE-HS2) had lower volumes only in CA1 (p ≤ 0.038). Neuronal cell densities always decreased in CA4, CA3, CA2, and CA1 of TLE-HS1 but only in CA1 of TLE-HS2 (p ≤ 0.003). In addition, TLE-HS2 had a higher volume (p = 0.016) and higher neuronal density (p < 0.001) than the TLE-HS1 in DG + CA4. Automatic segmentation failed to match the manual or histological findings and was unable to differentiate TLE-HS1 from TLE-HS2. Total hippocampal volume correlated with DG+CA4 and CA1 volumes and neuronal density. For the first time, we also identified subfield-specific pathology patterns in the manual evaluation of volumetric MRI scans, showing the importance of manual segmentation to assess subfield-specific pathology patterns.

Effects of sodium nitroprusside in the prevention of schizophrenia-like symptoms induced by ketamine - A translational double-blind study

Abstract Background: Recent evidence has shown improvements in schizophrenia symptoms after the infusion of sodium nitroprusside (SNP), a nitric oxide (NO) donor. In the rat model of schizophrenia using ketamine injection, pretreatment with SNP seems to prevent behavioral changes associated with positive symptoms for up to one week. Objective: We investigated whether SNP would have preventative effects on psychogenic symptoms induced by ketamine in healthy subjects. Methods: Healthy subjects (N = 38) were assigned to distinct groups that received SNP in different doses (0.15, 0.25, and 0.5 mcg/kg/min). First, participants received an infusion of SNP or placebo over 75 minutes. After 10 minutes, they were injected for 1 minute with a bolus of 0.26 mg/kg of ketamine and a maintenance dose was started 5 minutes later, with 0.25 mg/kg/h of ketamine for 50 minutes. Results: Ketamine-induced psychopathological alterations induced were reduced by SNP, as assessed with the Brief Psychological Rating Scale. Scores in the objective subscale of the Clinician-Administered Dissociative States Scale were also lower in SNP sessions compared to placebo. SNP had protective effects against deterioration in facial emotion and identity recognition tasks induced by ketamine. Discussion: Our findings support the view that SNP has preventative properties against psychotic manifestations.

Conhecimento de Libras pelos Médicos do Distrito Federal e Atendimento ao Paciente Surdo / Medical Doctors' Knowledge of Libras in the Federal District and Deaf Patient Health Care

RESUMO O ensino da Língua Brasileira de Sinais (Libras) nas escolas médicas é pouco difundido, e este cenário pode dificultar o atendimento de importante parcela da população: o paciente surdo. De acordo com o Instituto Brasileiro de Geografia e Estatística (IBGE), cerca de 24% da população brasileira tem algum tipo de deficiência, sendo parte de um grupo conhecido como vulneráveis. A surdez está entre as deficiências mais prevalentes, e no contexto do atendimento médico a dificuldade em atender integralmente o paciente surdo constitui um problema de saúde pública relevante, mas pouco abordado. O objetivo do presente estudo foi avaliar o conhecimento de Libras por médicos do Distrito Federal e sua percepção frente ao atendimento de pacientes surdos. Assim, foi realizado um estudo observacional transversal e descritivo com aplicação de questionários a 101 médicos escolhidos ao acaso, atuantes no Sistema Único de Saúde (SUS) no Distrito Federal. Foram entrevistados médicos de 24 especialidades, com idade média de 41 anos. Deles, 92,1% já atenderam um paciente surdo e 76,2% consideraram o conhecimento de Libras importante para sua prática médica, mas apenas um relatou conhecimento básico na língua. Quanto ao sentimento do médico no atendimento, houve predomínio de incerteza e desconforto. Um número significativo de médicos já realizou atendimento de pacientes surdos em sua prática profissional no SUS, e a maioria considerou o conhecimento de Libras relevante, especialmente os médicos com menos de 55 anos de idade. Possivelmente, o sentimento de desconforto no atendimento decorre do predominante desconhecimento da língua pelos médicos e da conseguinte dificuldade durante o atendimento. Destaca-se a importância da implantação ou ampliação do estudo de Libras antes ou durante a formação médica e dos demais cursos da área de saúde. A conscientização dos profissionais de saúde perante o atendimento integral do paciente surdo é um passo fundamental na implementação efetiva do ensino de Libras de forma especializada no ensino superior, resultando em maior confiança e qualidade na relação médico-paciente.

ABSTRACT In medical schools, the teaching of Brazilian Sign Language (Libras) is limited and this scenario may result in difficulties when dealing with an important portion of the population: the deaf. According to the Brazilian Institute of Geography and Statistics (IBGE), nearly 24% of the Brazilian population has some kind of deficiency; belonging to what are known as vulnerable groups. Deafness is among the most prevalent deficiencies, and the medical practice being unable to attend a deaf patient is a public health problem that requires further discussion. The objective of the present study was to evaluate medical doctors' knowledge of Libras and their perception of attending to a deaf patient. A cross-sectional and descriptive study was designed and 101 medical doctors of the Brazilian Public Health System (Sistema Único de Saúde, SUS) were randomly chosen in the Federal District and answered a structured survey. We interviewed medical doctors with a mean age of 41 years from 24 different medical specialties. 92.1% of them had seen at least one deaf patient in their clinical practice. 76.2% of them considered the knowledge of Libras relevant to their practice, but only one declared basic knowledge of the language. Most of the medical doctors reported uncertainty and discomfort when attending a deaf patient. A significant number of doctors had already seen a deaf patient in their clinical practice, and most considered the knowledge of Libras important, especially those under the age of 55 years. The feeling of discomfort when dealing with a deaf patient possibly arises from not knowing Libras and being unable to communicate with the patient properly. We emphasize the importance of learning Libras before or during medical school and other health-related courses. Being aware that the deaf patient deserves full health assistance is fundamental, and it may improve specialized learning of Libras and consequently result in a better doctor-patient relationship.

Protective Effects of Cannabidiol against Seizures and Neuronal Death in a Rat Model of Mesial Temporal Lobe Epilepsy.

The present study reports the behavioral, electrophysiological, and neuropathological effects of cannabidiol (CBD), a major non-psychotropic constituent of Cannabis sativa, in the intrahippocampal pilocarpine-induced status epilepticus (SE) rat model. CBD was administered before pilocarpine-induced SE (group SE+CBDp) or before and after SE (group SE+CBDt), and compared to rats submitted only to SE (SE group), CBD, or vehicle (VH group). Groups were evaluated during SE (behavioral and electrophysiological analysis), as well as at days one and three post-SE (exploratory activity, electrophysiological analysis, neuron density, and neuron degeneration). Compared to SE group, SE+CBD groups (SE+CBDp and SE+CBDt) had increased SE latency, diminished SE severity, increased contralateral afterdischarge latency and decreased relative powers in delta (0.5-4 Hz) and theta (4-10 Hz) bands. Only SE+CBDp had increased vertical exploratory activity 1-day post SE and decreased contralateral relative power in delta 3 days after SE, when compared to SE group. SE+CBD groups also showed decreased neurodegeneration in the hilus and CA3, and higher neuron density in granule cell layer, hilus, CA3, and CA1, when compared to SE group. Our findings demonstrate anticonvulsant and neuroprotective effects of CBD preventive treatment in the intrahippocampal pilocarpine epilepsy model, either as single or multiple administrations, reinforcing the potential role of CBD in the treatment of epileptic disorders.

Selective post-training time window for memory consolidation interference of cannabidiol into the prefrontal cortex: Reduced dopaminergic modulation and immediate gene expression in limbic circuits.

The prefrontal cortex (PFC), amygdala and hippocampus display a coordinated activity during acquisition of associative fear memories. Evidence indicates that PFC engagement in aversive memory formation does not progress linearly as previously thought. Instead, it seems to be recruited at specific time windows after memory acquisition, which has implications for the treatment of post-traumatic stress disorders. Cannabidiol (CBD), the major non-psychotomimetic phytocannabinoid of the Cannabis sativa plant, is known to modulate contextual fear memory acquisition in rodents. However, it is still not clear how CBD interferes with PFC-dependent processes during post-training memory consolidation. Here, we tested whether intra-PFC infusions of CBD immediately after or 5h following contextual fear conditioning was able to interfere with memory consolidation. Neurochemical and cellular correlates of the CBD treatment were evaluated by the quantification of extracellular levels of dopamine (DA), serotonin, and their metabolites in the PFC and by measuring the cellular expression of activity-dependent transcription factors in cortical and limbic regions. Our results indicate that bilateral intra-PFC CBD infusion impaired contextual fear memory consolidation when applied 5h after conditioning, but had no effect when applied immediately after it. This effect was associated with a reduction in DA turnover in the PFC following retrieval 5days after training. We also observed that post-conditioning infusion of CBD reduced c-fos and zif-268 protein expression in the hippocampus, PFC, and thalamus. Our findings support that CBD interferes with contextual fear memory consolidation by reducing PFC influence on cortico-limbic circuits.

Individual hippocampal subfield assessment indicates that matrix macromolecules and gliosis are key elements for the increased T2 relaxation time seen in temporal lobe epilepsy.

OBJECTIVE: Increased T2 relaxation time is often seen in temporal lobe epilepsy (TLE) with hippocampal sclerosis. Water content directly affects the effective T2 in a voxel. Our aim was to evaluate the relation between T2 values and two molecules associated with brain water homeostasis aquaporin 4 (AQP4) and chondroitin sulfate proteoglycan (CSPG), as well as cellular populations in the hippocampal region of patients with TLE. METHODS: Hippocampal T2 imaging and diffusion tensor imaging (DTI) were obtained from 42 drug-resistant patients with TLE and 20 healthy volunteers (radiologic controls, RCs). A similar protocol (ex vivo) was applied to hippocampal sections from the same TLE cases and 14 autopsy control hippocampi (histologic and radiologic controls, HRCs), and each hippocampal subfield was evaluated. Hippocampal sections from TLE cases and HRC controls were submitted to immunohistochemistry for neurons (neuron nuclei [NeuN]), reactive astrocytes (glial fibrillary acidic protein [GFAP]), activated microglia (human leukocyte antigen-D-related [HLA-DR]), polarized AQP4, and CSPG. RESULTS: Patients with TLE had higher in vivo and ex vivo hippocampal T2 relaxation time. Hippocampi from epilepsy cases had lower neuron density, higher gliosis, decreased AQP4 polarization, and increased CSPG immunoreactive area. In vivo relaxation correlated with astrogliosis in the subiculum and extracellular CSPG in the hilus. Ex vivo T2 relaxation time correlated with astrogliosis in the hilus, CA4, and subiculum, and with microgliosis in CA1. The difference between in vivo and ex vivo relaxation ratio correlated with mean diffusivity and with the immunopositive area for CSPG in the hilus. SIGNIFICANCE: Our data indicate that astrogliosis, microgliosis, and CSPG expression correlate with the increased T2 relaxation time seen in the hippocampi of patients with TLE.

Identification of microRNAs with Dysregulated Expression in Status Epilepticus Induced Epileptogenesis.

The involvement of miRNA in mesial temporal lobe epilepsy (MTLE) pathogenesis has increasingly become a focus of epigenetic studies. Despite advances, the number of known miRNAs with a consistent expression response during epileptogenesis is still small. Addressing this situation requires additional miRNA profiling studies coupled to detailed individual expression analyses. Here, we perform a miRNA microarray analysis of the hippocampus of Wistar rats 24 hours after intra-hippocampal pilocarpine-induced Status Epilepticus (H-PILO SE). We identified 73 miRNAs that undergo significant changes, of which 36 were up-regulated and 37 were down-regulated. To validate, we selected 5 of these (10a-5p, 128a-3p, 196b-5p, 352 and 324-3p) for RT-qPCR analysis. Our results confirmed that miR-352 and 196b-5p levels were significantly higher and miR-128a-3p levels were significantly lower in the hippocampus of H-PILO SE rats. We also evaluated whether the 3 miRNAs show a dysregulated hippocampal expression at three time periods (0h, 24h and chronic phase) after systemic pilocarpine-induced status epilepticus (S-PILO SE). We demonstrate that miR-128a-3p transcripts are significantly reduced at all time points compared to the naïve group. Moreover, miR-196b-5p was significantly higher only at 24h post-SE, while miR-352 transcripts were significantly up-regulated after 24h and in chronic phase (epileptic) rats. Finally, when we compared hippocampi of epileptic and non-epileptic humans, we observed that transcript levels of miRNAs show similar trends to the animal models. In summary, we successfully identified two novel dysregulated miRNAs (196b-5p and 352) and confirmed miR-128a-3p downregulation in SE-induced epileptogenesis. Further functional assays are required to understand the role of these miRNAs in MTLE pathogenesis.

Nitric Oxide's Involvement in the Spectrum of Psychotic Disorders.

BACKGROUND: Recent findings suggest that dopaminergic abnormalities found in psychotic disorders may be secondary to nitric oxide dysfunctions. Nitric oxide seems to influence glutamatergic and dopaminergic neurotransmission, both of which have been associated with psychosis. OBJECTIVE: To search and review published works which examined the influence of nitric oxide in psychotic disorders subjects. METHODS: The research was executed in the on-line collections of Pubmed and ISI Web of Science. The key aspects utilized were "Psychotic Disorders AND Nitric Oxide", "Psychosis AND Nitric Oxide","Schizotypal Personality Disorder AND Nitric Oxide", "Delusional Disorder AND Nitric Oxide", "Brief Psychotic Disorder AND Nitric Oxide", "Schizophreniform Disorder AND Nitric Oxide", "Schizoaffective Disorder AND Nitric Oxide", and "Schizophrenia AND Nitric Oxide". Empirical works utilizing human subjects, published in the last 10 years, in English language were included. RESULTS: Initially, the search yielded a total of 95 studies. Then, 39 were elected according to the inclusion requirements. The selected articles were divided into five groups: biochemical studies (n=15; 38.5%), genetic studies (n=11; 28.2%), postmortem studies (n=6; 15.4%), clinical trials (n=6; 15.4%), and case reports (n=1; 2.5%). The studies evaluated only schizophrenic or schizoaffective disorder subjects. The great majority of them found evidence of nitric oxide dysfunctions in psychosis. CONCLUSIONS: The results of the review strengthen the idea that nitric oxide has a key participation in psychotic disorders and deserves deeper investigation as a target for future pharmacological intervention.

Role of Methylene Blue in Trauma Neuroprotection and Neuropsychiatric Diseases.

The prevalence of central nervous system trauma, neurodegenerative and psychiatric diseases has significantly increased in recent years. Most of these diseases show multifactorial causes and several progression mechanisms. The search for a medication which positively interferes in these mechanisms and thereby changes the course of these diseases is of great scientific interest. The aim of the present review is to assess current literature on the possible role of methylene blue (MB) in the central nervous system due to the increasing number of citations in spite of the few articles available on the subject which suggest growing interest in the protective effects of MB on the central nervous system. Searches were performed on PubMed and Thomson Reuters Web of Knowledge. Therefore, we provide an overview of existing articles concerning: 1) MB actions; 2) MB neuroprotection and cardiac arrest; 3) MB neuroprotection and degenerative brain diseases; 4) MB neuroprotection and psychiatric diseases. PubMed was chosen because it holds the highest number of articles on the subject, Thomson Reuters was chosen due to its functionality which evaluates citations through analytic graphs. We conclude that MB has a beneficial effect and acts through many mechanisms and pathways of the central nervous system, being a potential alternative for the treatment of many neurodegenerative and psychiatric diseases.

Correction: Increased Metallothionein I/II Expression in Patients with Temporal Lobe Epilepsy.

[This corrects the article DOI: 10.1371/journal.pone.0044709.].

Inflammatory reaction In epilepsy / Reação inflamatória na epilepsia / Reacción inflamatoria En la epilepsia

Epilepsies are the second most common neurological disease. The pathological mechanisms of this disease are not fully unders- tood. Several studies claim that inflammation plays a significant role both in structural and physiological changes that lead to the emergence of seizures. Although in some epilepsies, such as Rasmussen?s encephalitis, the inflammation has definite importance, in several other epileptic syndromes, the participation of inflammatory reaction still lacks evidence. In such cases, the experimental models are useful for reveal how cytokines, molecules that modulate the inflammatory response, may affect seizures and how seizures may change the expression of these inflammatory molecules. Even with these works, much remains to be clarified with regard to the influence of inflammation on epileptic syndromes. The purpose of this brief review is to discuss the links between inflammatory processes, the origin of crises, and tissue damages in epilepsy.

As epilepsias são a segunda doença neurológica mais frequentes. Os mecanismos patológicos dessa doença ainda não são completamente compreendidos. Vários trabalhos alegam que a inflamação tem um papel importante tanto nas alterações estruturais quanto fisiológicas que levam à geração de crises. Embora em alguns tipos de epilepsia, como a encefalite de Rasmussen, a inflamação tenha importância evidente, em várias outras síndromes epilépticas ainda faltam evidências para confirmar a participação da reação inflamatória. Nesses casos, os modelos experimentais são úteis para revelar como as citocinas, moléculas que modulam a resposta inflamatória, podem afetar as crises e como as crises podem alterar a expressão dessas moléculas inflamatórias. Mesmo com esses trabalhos, muito ainda precisa ser esclarecido com relação à influência da inflamação sobre as síndromes epilépticas. O objetivo desta breve revisão foi discutir as ligações entre os processos inflamatórios, a origem das crises e os danos teciduais na epilepsia.

Las epilepsias son la segunda enfermedad neurológica más común. Los mecanismos patológicos de esta enfermedad no se entienden completamente. Varios estudios afirman que la inflamación juega un papel importante tanto en los cambios estructurales como en los fisiológicos que conducen a la generación de las convulsiones. Aunque en algunos tipos de epilepsia, tales como la encefalitis de Rasmus- sen, la inflamación tiene una importancia evidente, en varios otros síndromes epilépticos todavía carecen de pruebas para confirmar la participación de la reacción inflamatoria. En estos casos, los modelos experimentales son útiles para revelar cómo las citoquinas, molé- culas que modulan la respuesta inflamatoria, pueden afectar a las convulsiones y cómo las convulsiones pueden cambiar la expresión de estas moléculas inflamatorias. Incluso con estos trabajos, queda mucho por aclarar con respecto a la influencia de la inflamación en los síndromes epilépticos. El propósito de esta breve revisión es discutir los vínculos entre los procesos inflamatorios, el origen de la crisis y el daño tisular en la epilepsia.

Beta-tubulin expression In the hippocampus Of patients with mesial temporal lobe epilepsy / Expressão de beta-tubulina no hipocampo de pacientes com epilepsia do lobo temporal mesial / Expresión de beta-tubulina en el hipocampo de los pacientes con epilepsia del lóbulo temporal mesial

Introduction: The neuronal loss and abnormal mossy fibers sprouting are frequently observed in patients with mesial temporal lobe epilepsy (MTLE). Beta-tubulin, a cytoskeleton protein, is critical for the maintenance of the neuritic structure. Objective: Considering the axonal reorganization in patients with MTLE, our objective was to analyze the beta-tubulin expression in the hippocampus of these patients. Methods: We evaluated the hippocampus of 38 MTLE patients and seven control cases. Histological sections were submitted to neo-Timm histochemistry to evaluate the sprouting of mossy fiber, and to immunohis- tochemistry for neuronal density evaluation (NeuN) and beta-tubulin expression. Results: The MTLE group showed lower neuronal density than the control group in the granular layer (GL), hilus, CA4, CA3, CA1, and presubiculum. The MTLE group showed higher gray value on the neo-Timm staining when compared to the control group in GL, IML, and outer mo- lecular layer (OML), and sprouting of thicker mossy fibers in the IML. When compared to the control group, group MTLE showed higher beta-tubulin expression in GL and lower expression in CA3 region. The aberrant sprouting of mossy fibers correlated inversely with the beta-tubulin expression in several subs of the hippocampal formation. Conclusions: The differential expression of beta-tubulin in the regions CA3 and GL of the MTLE group, as well as its correlation with neuronal loss and the mossy fiber sprouting, suggests a possible role of this protein in the neuropathological changes that occur in the hippocampus in chronic cases of MTLE.

Introdução: A perda neuronal e o brotamento anormal de fibras musgosas são observados com frequência em pacientes com epilepsia do lobo temporal mesial (ELTM). A beta-tubulina, uma proteína do citoesqueleto, é essencial para a manutenção da estrutura neurítica. Objetivo: Considerando a reorganização axonal nos pacientes com ELTM, nosso objetivo foi analisar a expressão de beta-tubulina no hipo- campo desses pacientes. Métodos: Foram avaliados 38 hipocampos de pacientes com ELTM e sete casos controle. Cortes histológicos foram submetidos à histoquímica de neo-Timm para avaliação do neobrotamento de fibras musgosas e à imuno-histoquímica para avaliações da densidade neuronal (NeuN) e da expressão de beta-tubulina. Resultados: O grupo ELTM apresentou menor densidade neuronal do que o grupo controle na camada granular (CG), hilo, CA4, CA3, CA1 e no pró-subículo. O grupo ELTM apresentou maior valor de cinza na coloração neo-Timm com relação ao grupo controle na CG, CMI e camada molecular externa (CME) e neobrotamento mais espesso de fibras musgosas na CMI. O grupo ELTM apresentou maior expressão de beta-tubulina na CG e menor expressão na região de CA3, quando comparado ao grupo controle. O neobrotamento aberrante de fibras musgosas correlacionou-se inversamente com a expressão de beta-tubulina em diversos subcampos da formação hipocampal. Conclusões: A expressão diferencial da beta-tubulina nas regiões da CA3 e CG do grupo ELTM, assim como suas correlações com a perda neuronal e o neobrotamento de fibras musgosas sugerem uma possível participação dessa proteína nas alterações neuropatológicas que ocorrem no hipocampo nos casos crônicos de ELTM.

Introducción: La pérdida neuronal y la brotación anormal de fibras musgosas se observan con frecuencia en los pacientes con epilepsia del lóbulo temporal mesial (ELTM). La beta-tubulina, una proteína del citoesqueleto, es crítica para el mantenimiento de la estructura neurítica. Objetivo: Teniendo en cuenta la reorganización axonal en pacientes con ELTM, nuestro objetivo fue analizar la expresión de beta-tubulina en el hipocampo de estos pacientes. Métodos: Se evaluó el hipocampo de 38 pacientes con ELTM y siete casos de control. Cortes histológicos fueron sometidos a la histoquímica neo-Timm para evaluar la brotación de fibras musgosas, y a inmunohistoquímica para la evaluación de la densidad neuronal (NeuN) y la expresión de beta-tubulina. Resultados: El grupo ELTM mostró una menor densidad neuronal que el grupo control en la capa granular (CG), hilo, CA4, CA3, CA1 y pró-subículo. El grupo ELTM mostró mayor valor de gris en la tinción neo-Timm en comparación con el grupo control en CG, CMI y en la capa externa molecular (CME), y la brotación de fibras musgosas más gruesas en la CMI. El grupo ELTM mostró una mayor expresión de beta- tubulina en CG y expresión más baja en la región CA3, cuando se compara con el grupo control. La brotación aberrante de fibras musgosa está inversamente correlacionada con la expresión de beta-tubulina en varios subcampos de la formación del hipocampo. Conclusiones: La expresión diferencial de beta-tubulina en las regiones CA3 y CG del grupo ELTM, así como su correlación con la pérdida neuronal y el surgimiento de fibras musgosas, sugiere un posible papel de esta proteína en los cambios neuropatológicos que se producen en el hipocampo en los casos crónicos de ELTM.

Temporal lobe epilepsy patients with severe hippocampal neuron loss but normal hippocampal volume: Extracellular matrix molecules are important for the maintenance of hippocampal volume.

OBJECTIVE: Hippocampal sclerosis is a common finding in patients with temporal lobe epilepsy (TLE), and magnetic resonance imaging (MRI) studies associate the reduction of hippocampal volume with the neuron loss seen on histologic evaluation. Astrogliosis and increased levels of chondroitin sulfate, a major component of brain extracellular matrix, are also seen in hippocampal sclerosis. Our aim was to evaluate the association between hippocampal volume and chondroitin sulfate, as well as neuronal and astroglial populations in the hippocampus of patients with TLE. METHODS: Patients with drug-resistant TLE were subdivided, according to hippocampal volume measured by MRI, into two groups: hippocampal atrophy (HA) or normal volume (NV) cases. Hippocampi from TLE patients and age-matched controls were submitted to immunohistochemistry to evaluate neuronal population, astroglial population, and chondroitin sulfate expression with antibodies against neuron nuclei protein (NeuN), glial fibrillary acidic protein (GFAP), and chondroitin sulfate (CS-56) antigens, respectively. RESULTS: Both TLE groups were clinically similar. NV cases had higher hippocampal volume, both ipsilateral and contralateral, when compared to HA. Compared to controls, NV and HA patients had reduced neuron density, and increased GFAP and CS-56 immunopositive area. There was no statistical difference between NV and HA groups in neuron density or immunopositive areas for GFAP and CS-56. Hippocampal volume correlated positively with neuron density in CA1 and prosubiculum, and with immunopositive areas for CS-56 in CA1, and negatively with immunopositive area for GFAP in CA1. Multiple linear regression analysis indicated that both neuron density and CS-56 immunopositive area in CA1 were statistically significant predictors of hippocampal volume. SIGNIFICANCE: Our findings indicate that neuron density and chondroitin sulfate immunopositive area in the CA1 subfield are crucial for the hippocampal volume, and that chondroitin sulfate is important for the maintenance of a normal hippocampal volume in some cases with severe neuron loss.

Mesial temporal lobe epilepsy with psychiatric comorbidities: a place for differential neuroinflammatory interplay.

BACKGROUND: Despite the strong association between epilepsy and psychiatric comorbidities, few biological substrates are currently described. We have previously reported neuropathological alterations in mesial temporal lobe epilepsy (MTLE) patients with major depression and psychosis that suggest a morphological and neurochemical basis for psychopathological symptoms. Neuroinflammatory-related structures and molecules might be part of the altered neurochemical milieu underlying the association between epilepsy and psychiatric comorbidities, and such features have not been previously investigated in humans. METHODS: MTLE hippocampi of subjects without psychiatric history (MTLEW), MTLE + major depression (MTLE + D), and MTLE + interictal psychosis (MTLE + P) derived from epilepsy surgery and control necropsies were investigated for reactive astrocytes (glial fibrillary acidic protein (GFAP)), activated microglia (human leukocyte antigen, MHC class II (HLA-DR)), glial metallothionein-I/II (MT-I/II), and aquaporin 4 (AQP4) immunohistochemistry. RESULTS: We found an increased GFAP immunoreactive area in the molecular layers, granule cell layer, and cornus ammonis region 2 (CA2) and cornus ammonis region 1 (CA1) of MTLEW and MTLE + P, respectively, compared to MTLE + D. HLA-DR immunoreactive area was higher in cornus ammonis region 3 (CA3) of MTLE + P, compared to MTLE + D and MTLEW, and in the hilus, when compared to MTLEW. MTLEW cases showed increased MT-I/II area in the granule cell layer and CA1, compared to MTLE + P, and in the parasubiculum, when compared to MTLE + D and MTLE + P. Differences between MTLE and control, such as astrogliosis, microgliosis, increased MT-I/II, and decreased perivascular AQP4 in the epileptogenic hippocampus, were in agreement to what is currently described in the literature. CONCLUSIONS: Neuroinflammatory-related molecules in MTLE hippocampus show a distinct pattern of expression when patients present with a comorbid psychiatric diagnosis, similar to what is found in the pure forms of schizophrenia and major depression. Future studies focusing on inflammatory characteristics of MTLE with psychiatric comorbidities might help in the design of better therapeutic strategies.

Effects of nitric oxide-related compounds in the acute ketamine animal model of schizophrenia.

BACKGROUND: Better treatments for schizophrenia are urgently needed. The therapeutic use of the nitric oxide (NO)-donor sodium nitroprusside (SNP) in patients with schizophrenia has shown promising results. The role of NO in schizophrenia is still unclear, and NO modulation is unexplored in ketamine (KET) animal models to date. In the present study, we compared the behavioral effects of pre- and post-treatment with SNP, glyceryl trinitrate (GTN), and methylene blue (MB) in the acute KET animal model of schizophrenia. The present study was designed to test whether acute SNP, GTN, and MB treatment taken after (therapeutic effect) or before (preventive effect) a single KET injection would influence the behavior of rats in the sucrose preference test, object recognition task and open field. RESULTS: The results showed that KET induced cognitive deficits and hyperlocomotion. Long- term memory improvement was seen with the therapeutic GTN and SNP treatment, but not with the preventive one. MB pretreatment resulted in long-term memory recovery. GTN pre-, but not post-treatment, tended to increase vertical and horizontal activity in the KET model. Therapeutic and preventive SNP treatment consistently decreased KET-induced hyperlocomotion. CONCLUSION: NO donors - especially SNP - are promising new pharmacological candidates in the treatment of schizophrenia. In addition, we showed that the potential impact of NO-related compounds on KET-induced behavioral changes may depend on the temporal window of drug administration.

Hippocampal expression of heat shock proteins in mesial temporal lobe epilepsy with psychiatric comorbidities and their relation to seizure outcome.

OBJECTIVE: Biologic substrates behind the close association between mesial temporal lobe epilepsy (MTLE) and psychiatric comorbidities are largely unknown. Heat shock protein 70 (HSP70) and HSP90 are ubiquitous molecular chaperones that play important roles in functions from cellular stress response to receptor trafficking control. There are controversial findings regarding HSP expression in epilepsy. Our goal was to examine HSP70 and HSP90 expression within the human hippocampal formation of MTLE patients with and without comorbid major depression and psychosis. In addition, we investigated the possible correlation between HSP expression and seizure outcome. METHODS: MTLE hippocampi of subjects without psychiatric history, MTLE and major depression, and MTLE and interictal psychosis derived from epilepsy surgery and control necropsies were investigated for neuronal densities, HSP70 and HSP90 immunoreactive area. RESULTS: Increased HSP expression in MTLE and decreased HSP expression in MTLE with psychosis cases were detailed. Patients taking fluoxetine showed increased HSP90 expression in CA1, and those taking haloperidol decreased HSP90 in the granular layer and subiculum. MTLE patients with complete seizure remission presented with decreased HSP70 expression in CA4 and subiculum and decreased HSP90 expression in the granular layer. SIGNIFICANCE: The present results provide the first demonstration of HSP expression in human MTLE hippocampal formation with and without psychiatric comorbidities. Distinct HSP70 and HSP90 expression might explain some of the structural and synaptic alterations differentially regulated in MTLE with and without psychiatric comorbidities. Increased HSPs expression in key hippocampal subfields would reflect increased epileptogenicity and poorer outcome of epilepsy surgery.