Oral microbiome and inflammatory bowel disease: New understanding and call to action

The relationship between the oral microbiome and inflammatory bowel disease (IBD) represents a rapidly evolving area of research that has expanded our understanding of IBD pathogenesis and progression. Traditionally, IBD was primarily associated with gut microbiome dysbiosis, but emerging evidence highlights the oral microbiome as a significant contributor, offering new insights into disease mechanisms and potential therapeutic strategies. This new understanding underscores the importance of integrating oral health into IBD care and calls for action to address this overlooked aspect of disease management.

### Key Insights into the Oral Microbiome and IBD:

1. **Oral Microbiome and Systemic Inflammation**:

• The oral cavity is home to a diverse microbial ecosystem that plays critical roles in maintaining immune balance, digestion, and pathogen defense. When oral microbiota become dysbiotic, they can contribute to systemic inflammation by translocating microbes into circulation, activating immune responses, and releasing proinflammatory mediators.
• Dysbiosis in the oral microbiome has been linked to gastrointestinal and systemic diseases, including IBD. This connection suggests that oral health is not isolated but intricately tied to gut health.

2. **Shared Microbial Signatures**:

• In patients with Crohn’s disease and ulcerative colitis (the two primary forms of IBD), studies have identified shared microbial signatures between the oral cavity and the gut. During active disease, oral-associated bacteria are enriched in the gut, disrupting intestinal barrier integrity and amplifying inflammation.
• Oral microbes can activate both innate and adaptive immune pathways, driving chronic inflammation through mechanisms such as cytokine signaling and oxidative stress.

3. **Periodontal Disease and IBD**:

• Periodontal disease, a common oral inflammatory condition, is highlighted as both a potential contributor to and consequence of IBD. This bidirectional relationship reflects the interconnected nature of oral and gut inflammation.
• Chronic periodontal inflammation may exacerbate IBD symptoms, while systemic inflammation from active IBD may worsen periodontal health.

4. **Metabolic Contributions**:

• Oral bacteria influence metabolic processes by producing inflammatory metabolites and altering short-chain fatty acid dynamics. These changes can further aggravate intestinal inflammation and contribute to IBD progression.

### Diagnostic and Therapeutic Implications:

1. **Biomarkers for Disease Activity**:

• Patterns in the oral microbiome may serve as biomarkers for IBD activity, offering new tools for diagnosis and disease monitoring. Identifying oral microbial signatures could help detect early signs of disease exacerbation.

2. **Targeting Oral Health in IBD Management**:

• Improved dental hygiene, periodontal therapy, and oral probiotics are proposed as adjunctive strategies to manage IBD. These interventions aim to restore oral microbiome balance, reduce systemic inflammation, and potentially alleviate IBD symptoms.
• Addressing oral health as part of IBD care may enhance treatment outcomes and support a more comprehensive approach to disease management.

### Call to Action:

The emerging evidence calls for integrating oral health into IBD care, emphasizing the need for personalized, mechanism-driven treatment approaches that consider both oral and gut microbiomes. This paradigm shift requires collaboration between gastroenterologists, dentists, and microbiome researchers to:

• Promote awareness of the oral–gut axis in IBD among healthcare providers.
• Develop diagnostic tools that leverage oral microbial patterns as biomarkers.
• Encourage patients with IBD to prioritize oral health through regular dental care and preventive measures.
• Explore therapeutic interventions targeting oral dysbiosis as a novel avenue for managing IBD.

In conclusion, the oral microbiome is a critical yet underappreciated factor in IBD pathogenesis and progression. Addressing oral health in IBD care has the potential to transform treatment strategies, offering a more holistic and effective approach to managing this chronic inflammatory condition.