Effects of S100B on Serotonergic Plasticity and Neuroinflammation in the Hippocampus in Down Syndrome and Alzheimer's Disease: Studies in an S100B Overexpressing Mouse Model

S100B promotes development and maturation in the mammalian brain. However, prolonged or extensive exposure can lead to neurodegeneration. Two important functions of S100B in this regard, are its role in the development and plasticity of the serotonergic neurotransmitter system, and its role in the cascade of glial changes associated with neuroinflammation. Both of these processes are therefore accelerated towards degeneration in disease processes wherein S100B is increased, notably, Alzheimer's disease (AD) and Down syndrome (DS). In order to study the role of S100B in this context, we have examined S100B overexpressing transgenic mice. Similar to AD and DS, the transgenic animals show a profound change in serotonin innervation. By 28 weeks of age, there is a significant loss of terminals in the hippocampus. Similarly, the transgenic animals show neuroinflammatory changes analogous with AD and DS. These include decreased numbers of mature, stable astroglial cells, increased numbers of activated microglial cells and increased microglial expression of the cell surface receptor RAGE. Eventually, the S100B transgenic animals show neurodegeneration and the appearance of hyperphosphorylated tau structures, as seen in late stage DS and AD. The role of S100B in these conditions is discussed

Transtorno do espectro autista: Caracterização clínica em pacientes de dois centros de referência em Bogotá, Colômbia

Introduction: Patients with autism spectrum disorders (ASD) present great heterogeneity in their behavioral, cognitive, medical and psychiatric characteristics. In our environment, there is no description of such variables. Even though other studies have described a characteristic clinical profile, it is necessary to know our white population. Objective: Clinically characterize patients diagnosed with ASD at two reference centers in Bogotá. Patients and methods: Retrospective, observational and descriptive study of a series of cases documented in medical records from January 2010 to January 2014. The clinical histories of all patients with a confirmed diagnosis of ASD were reviewed, including sociodemographic data, personal and family history, as well as risk factors described in the literature in relation to the occurrence of ASD; diagnostic aids, comorbidities, and treatment. Results: Eighty-one cases met the inclusion criteria. In the series, predominance was found in the male gender (94.1%), perinatal complications (43%) and prematurity (7.6%). The main comorbidities were behavioral disorders (63%), epilepsy (23.5%) and attention deficit hyperactivity disorder (23%). The association between epilepsy and intellectual disability was significant at 84% (p <0.001). The association with genetic syndromes or inborn errors of metabolism was minimal in our series. Complementary studies were normal in most cases. Conclusions: In our series, non-syndromic autism predominated; the clinical presentation, the diagnostic and therapeutic approach all agree with what is reported in the world literature. The clinical elements constitute the main diagnostic tool, and behavioral management is the pillar of treatment. Analytical studies focused on the most significant variables will allow for the creation of therapeutic strategies aimed at our population.Introducción. Los pacientes con trastornos del espectro autista (TEA) presentan gran heterogeneidad en sus características comportamentales, cognitivas, médicas y psiquiátricas. En nuestro medio, no existe una descripción de tales variables. Si bien otros estudios han descrito un perfil clínico característico, es necesario conocer nuestra población blanco. Objetivo. Caracterizar clínicamente los pacientes con diagnóstico de TEA de dos centros de referencia, en Bogotá. Pacientes y métodos. Estudio retrospectivo observacional y descriptivo de serie de casos documentados en historias clínicas de enero de 2010 a enero de 2014. Se revisaron las historias clínicas de todos los pacientes con TEA confirmada por diagnóstico, incluyendo datos sociodemográficos, antecedentes personales y familiares, así como factores de riesgo descritos en la literatura en relación con la aparición de TEA; ayudas diagnósticas, comorbilidades y tratamiento. Resultados. Ochenta y un casos cumplieron los criterios de inclusión. En la serie, se encontró predominio en el género masculino (94,1%), complicaciones perinatales (43%) y prematurez (7,6%). Las principales comorbilidades fueron trastornos conductuales (63%), epilepsia (23,5%) y trastorno por déficit de atención e hiperactividad (23%).Fue significativa la asociación entre epilepsia y discapacidad intelectual: 84% (p<0,001). La asociación con síndromes genéticos o errores innatos del metabolismo fue mínima en nuestra serie. Los estudios complementarios fueron normales en la mayoría de los casos. Conclusiones. En nuestra serie predominó el autismo no sindrómico; la presentación clínica, el abordaje diagnóstico y terapéutico concuerdan con lo reportado en la literatura mundial. Los elementos clínicos constituyen la principal herramienta diagnóstica, el manejo conductual es el pilar de tratamiento. Estudios analíticos enfocados hacia las variables más significativas, permitirán la creación de estrategias terapéuticas dirigidas a nuestra poblaciónIntrodução. Os pacientes com transtornos do espectro autista (TEA) apresentam grande heterogeneidade em suas características comportamentais, cognitivas, médicas e psiquiátricas. Em nosso meio, não existe uma descrição de tais variáveis. Se bem que outros estudos têm descrito um perfil clínico característico, é necessário conhecer nossa população alvo. Objetivo. Caracterizar clinicamente os pacientes com diagnóstico de TEA de dois centros de referência em Bogotá. Pacientes e Métodos. Estudo retrospectivo observacional e descritivo de serie de casos documentados em histórias clínicas de janeiro de 2010 a janeiro de 2014. Revisaram-se as histórias clínicas de todos os pacientes com TEA confirmada por diagnóstico, incluindo dados sócio demográficos, antecedentes pessoais e familiares, assim como fatores de risco descritos na literatura em relação com a aparição de TEA; ajudas diagnósticas, co-morbilidades e tratamento. Resultados. Oitenta e um casos cumpriram os critérios de inclusão. Na série, se encontrou predomínio no gênero masculino (94,1%), complicações perinatais (43%) e prematuridade (7,6%). As principais co-morbilidades foram transtornos de conduta (63%), epilepsia (23,5%) e transtorno por déficit de atenção e hiperatividade (23%). Foi significativa a associação entre epilepsia e incapacidade intelectual: 84% (p<0,001). A associação com síndromes genéticas ou erros inatos do metabolismo foi mínima em nossa série. Os estudos complementares foram normais na maioria dos casos. Conclusões. Em nossa série predominou o autismo não sindrômico; a apresentação clínica, a abordagem diagnóstica e terapêutica concordam com a informação reportada na literatura mundial. Os elementos clínicos constituem a principal ferramenta diagnóstica, o manejo da conduta é o pilar de tratamento. Estudos analíticos enfocados às variáveis mais significativas permitirão a criação de estratégias terapêuticas dirigidas a nossa população

Autism as a disorder of neural information processing: directions for research and targets for therapy

The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

The neurobiology of mouse models syntenic to human chromosome 15q

Autism is a neurodevelopmental disorder that manifests in childhood as social behavioral abnormalities, such as abnormal social interaction, impaired communication, and restricted interest or behavior. Of the known causes of autism, duplication of human chromosome 15q11–q13 is the most frequently associated cytogenetic abnormality. Chromosome 15q11–q13 is also known to include imprinting genes. In terms of neuroscience, it contains interesting genes such as Necdin, Ube3a, and a cluster of GABAA subunits as well as huge clusters of non-coding RNAs (small nucleolar RNAs, snoRNAs). Phenotypic analyses of mice genetically or chromosomally engineered for each gene or their clusters on a region of mouse chromosome seven syntenic to human 15q11–q13 indicate that this region may be involved in social behavior, serotonin metabolism, and weight control. Further studies using these models will provide important clues to the pathophysiology of autism. This review overviews phenotypes of mouse models of genes in 15q11–q13 and their relationships to autism

Structural, Metabolic, and Functional Brain Abnormalities as a Result of Prenatal Exposure to Drugs of Abuse: Evidence from Neuroimaging

Prenatal exposure to alcohol and stimulants negatively affects the developing trajectory of the central nervous system in many ways. Recent advances in neuroimaging methods have allowed researchers to study the structural, metabolic, and functional abnormalities resulting from prenatal exposure to drugs of abuse in living human subjects. Here we review the neuroimaging literature of prenatal exposure to alcohol, cocaine, and methamphetamine. Neuroimaging studies of prenatal alcohol exposure have reported differences in the structure and metabolism of many brain systems, including in frontal, parietal, and temporal regions, in the cerebellum and basal ganglia, as well as in the white matter tracts that connect these brain regions. Functional imaging studies have identified significant differences in brain activation related to various cognitive domains as a result of prenatal alcohol exposure. The published literature of prenatal exposure to cocaine and methamphetamine is much smaller, but evidence is beginning to emerge suggesting that exposure to stimulant drugs in utero may be particularly toxic to dopamine-rich basal ganglia regions. Although the interpretation of such findings is somewhat limited by the problem of polysubstance abuse and by the difficulty of obtaining precise exposure histories in retrospective studies, such investigations provide important insights into the effects of drugs of abuse on the structure, function, and metabolism of the developing human brain. These insights may ultimately help clinicians develop better diagnostic tools and devise appropriate therapeutic interventions to improve the condition of children with prenatal exposure to drugs of abuse

Nicotinic receptors

Regulation of normal or abnormal behaviour is critically controlled by the central serotonergic systems. Recent evidence has suggested that serotonin (5-HT) neurotransmission dysfunction contributes to a variety of pathological conditions, including depression, anxiety, schizophrenia and Parkinson’s disorders. There is also a great amount of evidence indicating that 5-HT signalling may affect the reinforcing properties of drugs of abuse by the interaction and modulation of dopamine (DA) function. This chapter is focused on one of the more addictive drugs, nicotine. It is widely recognised that the effects of nicotine are strongly associated with the stimulatory action it exhibits on mesolimbic DAergic function. We outline the role of 5-HT and its plethora of receptors, focusing on 5-HT2 subtypes with relation to their involvement in the neurobiology of nicotine addiction. We also explore the novel pharmacological approaches using 5-HT agents for the treatment of nicotine dependence. Compelling evidence shows that 5-HT2C receptor agonists may be possible therapeutic targets for smoking cessation, although further investigation is required.peer-reviewe