A caracterização molecular do microbioma gastrointestinal de pessoas autistas e neurotípicos: uma revisão sistemática

Abstract

Autism Spectrum Disorder (ASD) is a neurodevelopmental syndrome characterized by repetitive behavior patterns and difficulty in social interaction, which significantly affects the development of the person diagnosed with this comorbidity. Background: ASD has become a public health issue, as its prevalence has increased considerably over the years. There are reports in several recent studies suggesting significant changes in the bacterial intestinal microbiota of autistic people. The gut-brain axis induces a complex and bidirectional communication model. Dysbiosis signs are related to neurobehavioral disorders, disrupting social, emotional, and communication skills. Methods: The literature review, using original studies from clinical trials and observational studies, aimed to characterize the gastrointestinal microbiome's composition in individuals with ASD. We searched five literature databases (Cochrane via Cochrane Library, Embase, ISI - Web of Science, MEDLINE via PubMed and Scopus). Results: We found 1,597 published works. However, we converged this review's scope to investigate changes in the gastrointestinal microbiome among autistic individuals with dysbiosis compared to neurotypical individuals. We analyzed six studies, including 303 patients with ASD. The results showed that children with ASD indicated a decreased relative abundance of phylum Bacteroidetes, Firmicutes, Actinobacteria, and Proteobacteria. On the other hand, they showed an increase in relative abundance only in the phylum Acidobacteria. All compared to 45 neurotypical brothers, and 195 individuals in the control group, representing the existence of changes in the strains of the total detected microflora. Conclusions: The results show a change in the intestinal microbiota regarding the phyla (Bacteroidetes, Firmicutes, Actinobacteria, Proteobacteria, and Acidobacteria). The study was faced with a shortage of Randomized Clinical Trials (RCTs) concerning the gastrointestinal microbiome, and given the inconsistency of the results reported in the evaluated studies, it was impossible to perform the meta-analysis. Further studies are needed to elucidate the specific role of the intestinal microbiome of pathogenesis in ASD, especially concerning behavioral aspects.