An approach to gut microbiota profile in children with autism spectrum disorder

In recent years, there has been an increase in studies on the implications of gut microbiota (GM) on the behaviour of children with autism spectrum disorders (ASD) due to a dysbiosis in GM that can trigger onset, development or progression of ASD through the microbiota–gut–brain axis. The aim of this study is to carry out a systematic review of articles from the last 6 years that analyse GM in children with ASD compared to GM in control groups. Children with ASD showed a higher abundance of Roseburia and Candida genera, and lower abundance of Dialister, Bilophila, Veillonella, Streptococcus, Coprococcus and Prevotella genera. Those differences can be attributed to factors such as different nationalities, nature of control groups, place where the sample was taken, gastrointestinal (GI) problems or bacterial detection methods. It is still too early to define a specific GM profile of children with ASD, and future studies should focus on homogenizing the characteristics of samples and control groups. Furthermore, new multicentre studies should also focus on the impact of GM on GI physiology, neurophysiology and behaviour of children with ASD, and on performing psychometric analyses of the correlation between the severity of ASD behavioural symptoms and GM profiles

Metabolites of the gut microbiota involved in the autism spectrum disorder

En los últimos años, ha habido un aumento de los estudios que buscan comprender la relación existente entre el microbiota intestinal (MI) con el trastorno del espectro autista (TEA), que debe producirse a través del eje microbiota-intestino-cerebro. A pesar de que los distintos autores señalan que los cambios encontrados en distintos filos, familias y géneros bacterianos están implicados en el TEA, no hay consenso científico a día de hoy. Algunos autores apuntan a la posible relación existente entre dichas poblaciones bacterianas con ciertos productos de excreción o metabolitos como el ácido propiónico ya que aparecen con frecuencia en niños con TEA. Aunque en los últimos años la MI comienza a acumular evidencia científica, en términos de neurociencia, el estudio de la metabolómica asociada a la misma y los mecanismos mediante los cuales estos metabolitos pueden influir en la aparición y desarrollo del TEA aún permanece en sus primeros estadios.In recent years, there has been an increase in studies that seek to understand the relationship between gut microbiota (GM) with the behavior of people with autism spectrum disorders (ASD), which must occur through the microbiota-gut-brain axis. Although the different authors point out that the changes found in different phyla, families and bacterial genera are involved in ASD, there is no scientific consensus to date. Some authors point to the possible relationship between these bacterial populations with certain products of excretion or metabolites such as propionic acid since they frequently appear in children with ASD. Although in recent years the GM has begun to accumulate scientific evidence, in terms of neuroscience, the study of the metabolomics associated with it and the mechanisms by which these metabolites can influence the appearance and development of ASD remains in its first stages

Candida spp. in the gut microbiota of people with autism: a systematic review

Introducción. Existe gran interés en los estudios sobre las implicaciones que la microbiota intestinal ejerce en el comportamiento de personas con trastornos del espectro autista (TEA) a través del eje microbiota-intestino-cerebro. La mayoría de los estudios sobre microbiota están enfocados en la posible implicación de las bacterias sobre personas con TEA, pero pocos versan sobre el efecto de los microorganismos del reino Fungi. Sujetos y métodos. Se realiza una revisión sistemática mediante el protocolo PRISMA de la presencia de Candida spp. en las personas con TEA. Resultados. Se encontró un total de tres artículos tras aplicar los criterios de exclusión e inclusión de la revisión sistemática. Dos estudios coincidieron en mostrar diferencias significativas en el aumento de la frecuencia del género Candida spp. en personas con TEA, mientras que en otro no se hallaron diferencias. Conclusiones. Pese a que existe una clara falta de investigación tanto del género Candida ssp. como de todo el reino Fungi en las personas con TEA, los estudios apuntan a una importante presencia de dicho género en este colectivo. Concretamente, en los resultados encontrados se destaca la mayor prevalencia del género C. albicans en los niños con TEA. Sin embargo, aún se sabe poco sobre la implicación de Candida spp. y otros tipos de hongos sobre los síntomas gastrointestinales y la sintomatología del autismo en niños con TEA.Introduction. There is great interest in studies on the implications that gut microbiota exerts on the behavior of people with autism spectrum disorders (ASD), through the microbiota-gut-brain axis. Most studies on microbiota are focused on the possible involvement of bacteria on people with ASD, but few of them are focussed on the effect of microorganisms in the Fungi kingdom. Subjects and methods. The present study performs a systematic review of the presence of Candida spp. in people with ASD using the PRISMA method. Results. A total of three articles were found after applying the exclusion and inclusion criteria of the systematic review. Two studies coincided in reporting significant differences in the increase in the frequency of the Candida spp. genus in people with ASD. while the third study did not report significant differences of Candida spp. genus between people with ASD. Conclusions. Although there is a clear lack of investigation of both the Candida ssp. genus and the whole Fungi kingdom in people with ASD, the studies point to an important presence of this genre in this group. Specifically, in the results found in this review, the highest prevalence of the C. albicans in children with ASD stands out. However, little is still known about the involvement of Candida spp., and other types of fungi, on gastrointestinal symptoms and ASD symptoms, in children with ASD