Caracterização da microbiota intestinal, perfil inflamatório e integridade da barreira gastrointestinal de crianças diagnosticadas com transtorno do espectro autista

Abstract

Introduction: Autism Spectrum Disorder (ASD) is a complex and multifactorial condition that involves social and cognitive deficits in affected individuals. In this context, the study of the gut microbiota has gained relevance, as the microorganisms that compose it interact metabolically, immunologically, and hormonally with the host. Studies on the prevalence of specific strains in the gut microbiota of individuals with ASD are conflicting, and there is still no clear understanding of the microbiota profile in this population or its relationship with intestinal epithelial barrier composition, behavior, and food preferences.Objective: To characterize the gut microbiota and its antimicrobial resistance genes (ARG), as well as to evaluate the eating behavior of children with ASD. Methodology: A non-randomized controlled study was conducted with children diagnosed with autism (ASD) (n=18) and neurotypical children (NT) (n=20). Weight and height data were collected for anthropometric assessment, along with information on gastrointestinal symptoms. Fecal samples were collected for metagenomic sequencing and antimicrobial resistance gene analysis. Relative abundance, alpha diversity, and beta diversity analyses were performed to characterize the microbiota and resistance genes, along with differential relative abundance analysis. Zonulin, Claudin, and Occludin concentrations were analyzed from fecal samples. The Children's Eating Behavior Questionnaire (CEBQ) was used to assess eating behavior, while a 24-hour dietary recall (R24h) was employed to evaluate the level of processing and nutritional quality of foods consumed on the day prior to fecal sample collection. Additionally, blood samples were used to isolate polymorphonuclear cells (PBMCs) and measure TNF-α, IL-6, and IL1-β levels after exposure to lipopolysaccharides (LPS) (1μg/ml) and phytohemagglutinin (PHA) (10μg/ml) for 1 hour and 3 hours.Results: All children in the ASD group reported at least one gastrointestinal symptom. Fecal samples from children with ASD showed significantly lower alpha diversity than those from NT children (p=0.007). PERMANOVA analysis revealed that beta diversity was significantly different between groups (p=0.004), indicating some level of separation between groups in principal coordinate analysis. The genera Staphylococcus, Haemophilus, Brevibacterium, and Bifidobacterium were differentially abundant in children with ASD, whereas Stenotrophomonas and Enterobacter were more differentially abundant in the NT group. Zonulin, Claudin, and Occludin concentrations were significantly higher in the ASD group (p<0.001). Children in the ASD group had significantly lower mean scores in the "Food Selectivity" subscale (p=0.002) compared to NT children. However, they also consumed significantly fewer "salads" and "non-starchy vegetables" while consuming more "sugar-rich or sugar-added foods," "ready-to-eat and semi-processed industrialized foods," "low-nutritional-value beverages," and "fried foods, fatty meats, and fatty sauces" compared to NT children. In the antimicrobial resistance gene (ARG) analysis, an average of 782 genes was identified. The ASD group exhibited greater ARG diversity compared to the NT group (p<0.001). In the inflammatory cytokine analysis, children in the ASD group showed higher TNF-α and IL1-β concentrations at the 3-hour time point compared to the NT group for both LPS and PHA exposure.Conclusion: Children with ASD exhibit physiological alterations that impact their quality of life and responsiveness to treatments and therapies. Reduced microbial diversity, increased gut barrier permeability, and elevated inflammatory cytokine levels in ASD 22 children are key findings for characterizing physiological components in Brazilian children and developing strategies to mitigate these alterations.