Microbiome dysbiosis—changes in the composition of gut microbes that alter the metabolites present—has long been implicated in playing a causative role in the pathophysiology of autism spectrum disorder (ASD). However, the changes in the gut microbial metabolites that are associated with ASD-specific brain alterations have remained unknown.
Now, a new study suggests that gut microbiome dysbiosis in children with ASD may create an imbalance of metabolites in the digestive system—ultimately disrupting neurotransmitter production and influencing behavioral symptoms. The researchers correlated metabolites with brain differences observed in children with ASD and their behavioral characteristics, homing in on the tryptophan pathway. The research adds to a growing body of science implicating the gut-brain axis in autism and could raise the possibility of new treatment avenues.
This work is published in Nature Communications in the paper, “Relationships between brain activity, tryptophan-related gut metabolites, and autism symptomatology.”
“We demonstrated that gut metabolites impact the brain, and the brain, in turn, affects behavior. Essentially, the brain acts as the intermediary between gut health and autism-related behaviors,” said Lisa Aziz-Zadeh, PhD, professor at the Brain and Creativity Institute at the USC Dornsife College of Letters, Arts and Sciences. “Previous studies highlighted differences in gut microbiomes and brain structures in autism, but our research connects the dots.”
For the study, researchers collected behavioral data, brain imaging data, and stool samples from 43 children with autism and 41 neurotypical children aged 8–17. Analysis was completed on (i) fecal metabolomics, (ii) task-based functional magnetic resonance imaging (fMRI), and (iii) behavioral assessments. The fMRI tasks, the authors wrote, “used socio-emotional and sensory paradigms that commonly reveal strong evoked brain differences in ASD participants.”
The authors’ results showed “that fecal levels of specific tryptophan-related metabolites, including kynurenate, were significantly lower in ASD compared to NT, and were associated with: 1) alterations in insular and cingulate cortical activity previously implicated in ASD; and 2) ASD severity and symptoms (e.g., ADOS scores, disgust propensity, and sensory sensitivities).” They added that “activity in the mid-insula and mid-cingulate significantly mediated relationships between the microbial tryptophan metabolites (indolelactate and tryptophan betaine) and ASD severity and disgust sensitivity.”
“We know that children with autism have brain differences—certain parts of their brain are either less active or more active compared to typically developing children,” Aziz-Zadeh said. “We also know they often experience gastrointestinal issues, such as constipation, stomach pain, and other digestive problems. Additionally, autism is associated with various symptoms, including repetitive behaviors and social difficulties.”
Sofronia Ringold, a doctoral student at the Brain and Creativity Institute who worked on the study, said she was excited by the possibility of interventions that might target the gut and influence neural activity and behavior “while also hopefully alleviating some of the symptoms that are the most uncomfortable for them.”
The post Autism Symptoms Associated with Gut Microbial Tryptophan Metabolites appeared first on GEN - Genetic Engineering and Biotechnology News.
Now, a new study suggests that gut microbiome dysbiosis in children with ASD may create an imbalance of metabolites in the digestive system—ultimately disrupting neurotransmitter production and influencing behavioral symptoms. The researchers correlated metabolites with brain differences observed in children with ASD and their behavioral characteristics, homing in on the tryptophan pathway. The research adds to a growing body of science implicating the gut-brain axis in autism and could raise the possibility of new treatment avenues.
This work is published in Nature Communications in the paper, “Relationships between brain activity, tryptophan-related gut metabolites, and autism symptomatology.”
“We demonstrated that gut metabolites impact the brain, and the brain, in turn, affects behavior. Essentially, the brain acts as the intermediary between gut health and autism-related behaviors,” said Lisa Aziz-Zadeh, PhD, professor at the Brain and Creativity Institute at the USC Dornsife College of Letters, Arts and Sciences. “Previous studies highlighted differences in gut microbiomes and brain structures in autism, but our research connects the dots.”
For the study, researchers collected behavioral data, brain imaging data, and stool samples from 43 children with autism and 41 neurotypical children aged 8–17. Analysis was completed on (i) fecal metabolomics, (ii) task-based functional magnetic resonance imaging (fMRI), and (iii) behavioral assessments. The fMRI tasks, the authors wrote, “used socio-emotional and sensory paradigms that commonly reveal strong evoked brain differences in ASD participants.”
The authors’ results showed “that fecal levels of specific tryptophan-related metabolites, including kynurenate, were significantly lower in ASD compared to NT, and were associated with: 1) alterations in insular and cingulate cortical activity previously implicated in ASD; and 2) ASD severity and symptoms (e.g., ADOS scores, disgust propensity, and sensory sensitivities).” They added that “activity in the mid-insula and mid-cingulate significantly mediated relationships between the microbial tryptophan metabolites (indolelactate and tryptophan betaine) and ASD severity and disgust sensitivity.”
“We know that children with autism have brain differences—certain parts of their brain are either less active or more active compared to typically developing children,” Aziz-Zadeh said. “We also know they often experience gastrointestinal issues, such as constipation, stomach pain, and other digestive problems. Additionally, autism is associated with various symptoms, including repetitive behaviors and social difficulties.”
Sofronia Ringold, a doctoral student at the Brain and Creativity Institute who worked on the study, said she was excited by the possibility of interventions that might target the gut and influence neural activity and behavior “while also hopefully alleviating some of the symptoms that are the most uncomfortable for them.”
The post Autism Symptoms Associated with Gut Microbial Tryptophan Metabolites appeared first on GEN - Genetic Engineering and Biotechnology News.