The role of the microbiota-gut-brain axis in neuropsychiatric disorders

The microbiota-gut-brain axis is a bidirectional signaling mechanism between the gastrointestinal tract and the central nervous system. The complexity of the intestinal ecosystem is extraordinary; it comprises more than 100 trillion microbial cells that inhabit the small and large intestine, and this interaction between microbiota and intestinal epithelium can cause physiological changes in the brain and influence mood and behavior. Currently, there has been an emphasis on how such interactions affect mental health. Evidence indicates that intestinal microbiota are involved in neurological and psychiatric disorders. This review covers evidence for the influence of gut microbiota on the brain and behavior in Alzheimer disease, dementia, anxiety, autism spectrum disorder, bipolar disorder, major depressive disorder, Parkinson's disease, and schizophrenia. The primary focus is on the pathways involved in intestinal metabolites of microbial origin, including short-chain fatty acids, tryptophan metabolites, and bacterial components that can activate the host's immune system. We also list clinical evidence regarding prebiotics, probiotics, and fecal microbiota transplantation as adjuvant therapies for neuropsychiatric disorders.

Potencial antibacteriano e perfil farmacognóstico das folhas de Hibiscus acetosella Welw Ex Hiern / Antibacterial potential and pharmacognostic profile of Hibiscus acetosella Welw Ex Hiern

Introdução: as Hisbiscus pertencentes à família Malvaceae são amplamente utilizadas na área ornamental e vem ganhando espaço na área alimentícia com suas flores comestíveis e corantes naturais. Alguns estudos demonstraram atividade antibacteriana de algumas espécies deste gênero frente a diversos microorganismos. Hibiscus acetosella, também conhecida popularmente como vinagreira, possui em literatura científica pouca informação sobre sua composição química e ação antibacteriana. Objetivo: caracterizar o perfil farmacognóstico relacionando com a ação microbiológica das folhas de H. acetosella. Metodologia: o perfil farmacognóstico foi realizado através de testes de precipitação, teste colorimétrico, quantificação de compostos fenólicos e análise cromatográfica do extrato hidroalcoólico e das frações das folhas de H. acetocella. A ação antibacteriana do extrato hidroalcoólico (60 mg) e frações (25 mg) foi analisada frente aos microorganismos Staphylococcus aureus, Escherichia coli e Pseudomonas aeruginosa por meio do método de difusão em ágar. Resultados: a análise farmacognóstica apresentou resultados positivos para as classes de substâncias: taninos, flavonoides, cumarinas, heterosídeos cardiotônicos e alcaloides. O extrato hidroalcoólico possui aproximadamente 352,85 mg/L de polifenóis totais. As frações com caráter mais polar (n-butanol e acetato de etila) apresentaram efeito relevante contra os microorganismos S. aureus e P. aeruginosa. Conclusão: os resultados demonstraram que ação antibacteriana pode estar relacionada com a classe de com compostos fenólicos, uma vez que as frações que apresentaram melhor resultado possuem maior concentração destes metabólitos.

Introduction: the Hisbiscus belonging to the family Malvaceae are widely used in the ornamental area and have been gaining space in the food area with its edible flowers and natural dyes. Some studies have demonstrated antibacterial activity of some species of this genus against different microorganisms. Hibiscus acetosella, also popularly known as vinegar, has little scientific information about chemical composition and antibacterial action. Objective: caracterizar o perfil farmacognóstico relacionando com a ação microbiológica das folhas de H. acetosella. Method: the pharmacognostic profile was performed through precipitation tests, colorimetric test, quantification of phenolic compounds and chromatographic analysis of the hydroalcoholic extract and the fractions of the leaves of H. acetocella. The antibacterial action of the hydroalcoholic extract (60 mg) and fractions (25 mg) were analyzed against the microorganisms Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa through the agar diffusion method. Results: the pharmacognostic analysis presented positive results for the classes of substances: tannins, flavonoids, coumarins, cardiotonic heterosides and alkaloids. The hydroalcoholic extract has approximately 352.85 mg / L of total polyphenols. The most polar fractions (n-butanol and ethyl acetate) had a significant effect against the S. aureus and P. aeruginosa microorganisms. Conclusions: the results showed that the antibacterial action may be related to the class of phenolic compounds, since the fractions presented the best antibacterial result have a higher concentration of these metabolites.

Serum levels of neurotrophic factors in active toxoplasmic retinochoroiditis

Abstract Toxoplasmic retinochoroiditis (TR) is the most common identifiable cause of posterior uveitis in Brazil. Response to treatment and clinical presentation may vary significantly. We assessed serum levels of brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF), neurotrophin (NT)-3, and NT-4/5 in patients with active TR, before and after TR treatment. Methods: Twenty patients with active lesion and 15 healthy controls were enrolled in the study. Serum concentration of neurotrophic factors was determined by enzyme-linked immunosorbent assay. Results: BDNF levels were significantly higher in patients before treatment when compared with controls (p = 0.0015). There was no significant difference in pro-BDNF, NGF, GDNF, NT-3, and NT-4/5 levels between TR patients and controls. Treatment did not affect the levels of these factors. Conclusion: BDNF may be released in the context of the active TR inflammatory response.

Environmental enrichment restores cognitive deficits induced by experimental childhood meningitis

Objective: To evaluate the influence of environmental enrichment (EE) on memory, cytokines, and brain-derived neurotrophic factor (BDNF) in the brain of adult rats subjected to experimental pneumococcal meningitis during infancy. Methods: On postnatal day 11, the animals received either artificial cerebrospinal fluid (CSF) or Streptococcus pneumoniae suspension intracisternally at 1 × 106 CFU/mL and remained with their mothers until age 21 days. Animals were divided into the following groups: control, control + EE, meningitis, and meningitis + EE. EE began at 21 days and continued until 60 days of age (adulthood). EE consisted of a large cage with three floors, ramps, running wheels, and objects of different shapes and textures. At 60 days, animals were randomized and subjected to habituation to the open-field task and the step-down inhibitory avoidance task. After the tasks, the hippocampus and CSF were isolated for analysis. Results: The meningitis group showed no difference in performance between training and test sessions of the open-field task, suggesting habituation memory impairment; in the meningitis + EE group, performance was significantly different, showing preservation of habituation memory. In the step-down inhibitory avoidance task, there were no differences in behavior between training and test sessions in the meningitis group, showing aversive memory impairment; conversely, differences were observed in the meningitis + EE group, demonstrating aversive memory preservation. In the two meningitis groups, IL-4, IL-10, and BDNF levels were increased in the hippocampus, and BDNF levels in the CSF. Conclusions: The data presented suggest that EE, a non-invasive therapy, enables recovery from memory deficits caused by neonatal meningitis. .

Pathophysiology of bacterial infection of the central nervous system and its putative role in the pathogenesis of behavioral changes

Invasion of the central nervous system (CNS) by microorganisms is a severe and frequently fatal event during the course of many infectious diseases. It may lead to deafness, blindness, cerebral palsy, hydrocephalus, cognitive impairment or permanent neurological dysfunction in survivors. Pathogens can cross the blood-brain barrier by transcellular migration, paracellular migration and in infected macrophages. Pathogens may breach the blood-brain barrier and be recognized by antigen-presenting cells through the binding of Toll-like receptors. This induces the activation of nuclear factor kappa B or mitogen-activated protein kinase pathways and subsequently induces leukocyte infiltration and proliferation and the expression of numerous proteins involved in inflammation and the immune response. Many brain cells can produce cytokines, chemokines and other pro-inflammatory molecules in response to bacteria stimuli; as a consequence, polymorphonuclear cells are attracted and activated, and release large amounts of superoxide anion and nitric oxide, leading to peroxynitrite formation and oxidative stress. This cascade leads to lipid peroxidation, mitochondrial damage and blood-brain barrier breakdown, contributing to cellular injury during neuronal infection. Current evidence suggests that bacterial CNS infections can play a role in the etiopathogenesis of behavioral disorders by increasing pro-inflammatory cytokines and bacterial virulence factors. The aim of this review is to summarize the current knowledge of the relevant pathophysiologic steps in CNS infections.

Microbiological evaluation of bristles of frequently used toothbrushes / Avaliação microbiológica das cerdas de escovas dentárias de uso frequente

INTRODUCTION: Brushing teeth is probably the practice of oral hygiene most common in the world; however, inadequate use can become a risk to the population health, once they may be contaminated with various microorganisms. OBJECTIVE: The aim of this study was to evaluate the bacterial contamination on toothbrush bristles using different methodologies. METHOD: We used 40 toothbrushes from healthy individuals aged 3 to 58 years. The samples were grown in test tubes containing trypticase soy broth sterile, and with the help of a tracking 0.1 μl samples were placed on plates containing sheep blood agar 5% and MacConkey agar then the samples were stored in a bacteriological incubator at 37°C for 24 hours for later analysis. It was counted the colony forming units and bacteria identification present in the brush. RESULTS: On the microbiological analysis, there was a growth of Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes and Staphylococcus coagulase negative. CONCLUSION: According to the results presented in this study, we observed a high incidence of bacterial contamination in the brushes analyzed. The most frequent microorganisms were members of the Enterobacteriaceae. The usage time of toothbrushes may be related to contamination found and, therefore, not only good hygiene ensures the reduction of microbial load, but replacing the toothbrush can also ensure individuals better oral health.

INTRODUÇÃO: a escovação de dentes é, provavelmente, a prática de higiene bucal mais comumente realizada no mundo; entretanto, o acondicionamento inadequado pode se transformar em um risco para a saúde da população, uma vez que podem estar contaminadas com vários tipos de microrganismos. OBJETIVO: o objetivo desse estudo foi avaliar a contaminação bacteriana de cerdas de escovas dentais através de diferentes métodos. MÉTODOS: foram utilizadas 40 escovas de dentes provenientes de indivíduos sadios, com idade entre 3 a 58 anos. As amostras foram semeadas em tubo de ensaio contendo caldo tripticaseína de soja (TSB) estéril e, com o auxílio de uma alça de 0,1μl, as amostras foram semeadas em placas contendo ágar sangue de carneiro a 5% e ágar MacConkey. Em seguida foram armazenadas em estufa bacteriológica a 37°C por 24hs para posterior análise. Foi realizada a contagem das unidades formadora de colônias (UFC) e a identificação das bactérias presentes nas escovas. RESULTADOS: nas análises microbiológicas, houve crescimento de Escherichia coli, Klebsiella pneumoniae, Streptococcus pyogenes e Staphylococcus coagulase negativas. Conclusões: de acordo com os resultados apresentados nesse trabalho, verificamos que houve alta incidência de contaminação bacteriana nas escovas analisadas. Os microrganismos com maior frequência foram membros da família Enterobacteriaceae. O tempo de uso das escovas dentárias pode estar relacionado à contaminação encontrada e, por isso, não só uma boa higienização garantirá a redução da carga microbiana, mas a troca da escova dentária também pode garantir melhor saúde bucal aos indivíduos.

Pathophysiology of acute meningitis caused by Streptococcus pneumoniae and adjunctive therapy approaches / Fisiopatologia da meningite ocasionada pelo Streptococcus pneumoniae e novas possibilidades terapêuticas adjuvantes

Pneumococcal meningitis is a life-threatening disease characterized by an acute purulent infection affecting piamater, arachnoid and the subarachnoid space. The intense inflammatory host's response is potentially fatal and contributes to the neurological sequelae. Streptococcus pneumoniae colonizes the nasopharynx, followed by bacteremia, microbial invasion and blood-brain barrier traversal. S. pneumoniae is recognized by antigen-presenting cells through the binding of Toll-like receptors inducing the activation of factor nuclear kappa B or mitogen-activated protein kinase pathways and subsequent up-regulation of lymphocyte populations and expression of numerous proteins involved in inflammation and immune response. Many brain cells can produce cytokines, chemokines and others pro-inflammatory molecules in response to bacteria stimuli, as consequence, polymorphonuclear are attracted, activated and released in large amounts of superoxide anion and nitric oxide, leading to the peroxynitrite formation, generating oxidative stress. This cascade leads to lipid peroxidation, mitochondrial damage, blood-brain barrier breakdown contributing to cell injury during pneumococcal meningitis.

A meningite pneumocócica é doença potencialmente fatal caracterizada por infecção aguda purulenta que afeta a pia-máter, a aracnoide e o espaço subaracnoide. A resposta inflamatória do hospedeiro é potencialmente fatal e contribui para as sequelas neurológicas. O processo inicia-se com a colonização da nasofaringe pelo Streptococcus pneumoniae, seguida de invasão, bacteremia e passagem através da barreira hematoencefálica. O S. pneumoniae é reconhecido por células apresentadoras de antígenos através da ligação aos receptores Toll-like. Isto induz a ativação do fator nuclear kappa B ou proteína quinase ativada por mitógenos. Muitas células cerebrais também podem produzir citocinas, quimiocinas e outras moléculas pró-inflamatórias em resposta aos estímulos bacterianos. Como consequência, são atraídos polimorfonucleares, ocorrendo a liberação de grandes quantidades de ânion superóxido e óxido nítrico, o que leva à formação de peroxinitrito e ocasiona o estresse oxidativo. Esta cascata pró-inflamatória leva à peroxidação lipídica, a danos mitocondriais e à ruptura da barreira hematoencefálica, contribuindo para o dano celular em meningite pneumocócica.

Enteropatógenos associados com diarréia infantil (< 5 anos de idade) em amostra da população da área metropolitana de Criciúma, Santa Catarina, Brasil / Enteropathogens associated with diarrheal disease in infants (< 5 years old) in a population sample in Greater Metropolitan Criciúma, Santa Catarina State, Brazil

Foi investigada a presença de enteropatógenos em 94 casos de diarréia e 45 casos-controle em crianças de 0 a 5 anos de idade, atendidas no Centro de Saúde Municipal de Criciúma, Santa Catarina. Entre os parasitos isolados, o Cryptosporidium (85,1 por cento) foi o mais freqüente, seguido pela Entamoeba histolytica (56,4 por cento) e a Giardia lamblia (4,3 por cento). Quatro amostras apresentaram Escherichia coli enteropatogênica (4,3 por cento). A Samonella e a Shiguella näo foram detectadas em nenhuma amostra. Somente um caso foi positivo para o rotavírus (1,1 por cento)