Inflammatory bowel disease (IBD), including Crohn’s disease (CD) and ulcerative colitis (UC), is a chronic immune-mediated condition typically requiring invasive endoscopy for monitoring. The bidirectional oral-gut axis suggests that saliva may serve as a non-invasive diagnostic fluid for studying gut inflammations. Studies of salivary biomarkers have shown varying results. Inflammatory biomarkers such as IL-6 are the most robust salivary biomarker, consistently correlating with endoscopic activity. In contrast, salivary calprotectin lacks the reliability of its fecal counterpart, showing diagnostic value primarily in pediatric cases with oral manifestations. Microbial analysis indicates reduced salivary diversity, specifically an enrichment of Prevotella and Veillonella alongside a depletion of core commensals like Streptococcus. While oxidative stress markers such as advanced oxidation protein products (AOPPs) can distinguish disease severity, they lack long-term prognostic utility. Conversely, recent shifts toward exosome-based transcriptomic analysis have improved the stability of salivary microRNAs, offering high precision in differentiating IBD phenotypes. Despite these advancements, clinical integration is currently hindered by small cohort sizes, the confounding effects of local oral health, and a lack of standardized collection protocols. To establish saliva as a reliable tool in the IBD clinical toolkit, future research must prioritize multi-panel biomarker approaches and longitudinal studies to validate diagnostic accuracy across diverse patient populations.
Chrabié et al. (Thu,) studied this question.