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Potential association between altered oral microbiota and oxidative stress in individuals with autism.

Autism : the international journal of research and practice2025

Zhong Liyan, Ren Pengcheng, Wang Haibo, Fu Chenghui, Feng Dingxia, Wang Min, Zeng Liqin, Yao Paul, Wang Tao

What this study means for families

Researchers studied the bacteria in the mouth and stress markers in 54 people with autism compared to 46 people without autism. They found that people with autism had higher stress levels in their mouth cells and different types of bacteria in their mouth. This suggests that mouth bacteria might be connected to health issues in autism, which could lead to new treatment approaches.

Summary by AutismInsights from published abstract. This is not a substitute for reading the original paper.

Research summary

This case-control study examined oral microbiota and oxidative stress in 54 individuals with autism spectrum disorders compared to 46 typically developing controls. Participants with autism showed significantly increased oxidative stress markers, including suppressed antioxidant enzyme expression, elevated DNA damage markers, and reduced glutathione ratios in saliva. Additionally, oral microbiota analysis revealed significant differences in microbial diversity and community structure between groups. The findings suggest a potential link between altered oral bacterial communities and oxidative stress in autism, though the underlying mechanisms remain unclear.

This research provides new insights into autism pathology and potential therapeutic targets through the oral-gut axis.

Summary by AutismInsights from published abstract. This is not a substitute for reading the original paper.

Key findings

  • 1

    Individuals with autism showed suppressed antioxidant enzyme levels and increased oxidative stress markers in oral epithelial cells

    Confidence: moderateRelevance: May indicate systemic oxidative stress contributing to autism-related health issues
  • 2

    Significant differences in oral microbiota diversity and community structure between autism and control groups

    Confidence: moderateRelevance: Suggests oral microbiome could be a therapeutic target or biomarker for autism
  • 3

    Reduced glutathione ratio in saliva of individuals with autism

    Confidence: moderateRelevance: Indicates compromised antioxidant capacity potentially affecting overall health

Summary by AutismInsights from published abstract. This is not a substitute for reading the original paper.

Clinical implications

Findings suggest oral health assessment and microbiome-targeted interventions may benefit individuals with autism. Antioxidant support strategies could address oxidative stress. Further research needed to establish causal relationships and develop evidence-based therapeutic approaches targeting the oral-gut axis in autism.

Summary by AutismInsights from published abstract. This is not a substitute for reading the original paper.

Limitations

Small sample size limits generalizability. Cross-sectional design cannot establish causality between oral microbiota changes and oxidative stress. Underlying mechanisms linking these factors remain unclear. No information provided about participant demographics, autism severity, or potential confounding factors.

Summary by AutismInsights from published abstract. This is not a substitute for reading the original paper.

Original abstract

Autism spectrum disorders are potentially associated with gastrointestinal dysfunction, although the underlying mechanisms remain unclear. Recently, the oral cavity has gained attention as the starting point of the digestive tract. We aim to explore the potential association between altered oral microbiota and oxidative stress in individuals with autism spectrum disorders. We conducted a case-control study involving 54 subjects with autism spectrum disorders and 46 typically developing participants.

Oral epithelial cells and saliva samples were collected to analyze oxidative stress markers and oral microbiota composition using 16S rDNA sequencing. Compared with typically developing participants, individuals with autism spectrum disorders exhibited suppressed mRNA levels of superoxide dismutase 2 and RAR-related orphan receptor α, increased H3K9me2 modifications at superoxide dismutase 2 promoter, elevated levels of 8-oxo-dG in oral epithelial cells, and a reduced ratio of reduced glutathione/oxidized glutathione (GSH/GSSG) ratio in saliva. In addition, alpha and beta diversity analyses showed significant differences in microbial richness, evenness, and intersample variation between the autism spectrum disorder and typically developing groups. Statistical analyses confirmed marked distinctions in microbial diversity and community structure between the two groups.

Individuals with autism spectrum disorders show increased oxidative stress and altered oral microbiota compared with typically developing participants. While the underlying mechanisms remain unclear, these findings suggest that altered oral microbiota may be linked to oxidative stress, providing insights into autism spectrum disorder pathology and potential avenues for clinical intervention.Lay AbstractAutism spectrum disorders are linked to gut-related issues, but the exact causes are still unclear. Recent research focuses on the mouth, the first part of the digestive system, to understand how it may play a role. This study looked at how the oral microbiome (the community of microorganisms in the mouth) and oxidative stress (an imbalance between harmful free radicals and antioxidants in the body) differ in people with autism spectrum disorders compared with typically developing individuals.

Researchers studied 54 people with autism spectrum disorders and 46 typically developing individuals by analyzing their saliva and oral cells. Results showed that people with autism spectrum disorders had higher levels of oxidative stress markers and noticeable differences in their oral microbiota diversity and structure. These findings suggest a potential connection between changes in oral bacteria and oxidative stress in autism spectrum disorders, opening the door for new ways to study and treat autism spectrum disorders-related health issues.

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Evidence Grade

Emerging

limited

Grade assigned by AutismInsights based on study type and published abstract.

Study Details

Journal
Autism : the international journal of research and practice
Year
2025
PMID
40836857
DOI
10.1177/13623613251362259

MeSH Terms

HumansOxidative StressMaleFemaleCase-Control StudiesAutism Spectrum DisorderSalivaMouthMicrobiotaChildAdolescentAdultYoung Adult