Alterations in oral microbiome and salivary metabolome profiles associated with myocardial infarction: a case-control study

Background Few studies have comprehensively profiled both the salivary microbiome and metabolome in myocardial infarction (MI). This case-control study therefore characterized microbial and metabolic alterations in MI patients and identified potential diagnostic signatures.Methods Seventy participants (35 MI patients and 35 matched healthy controls) were enrolled. Salivary microbiota were profiled via 16S rRNA (V3–V4) sequencing, and metabolites were analyzed using untargeted LC-MS. Microbial diversity, taxonomic composition, and predicted functional pathways were assessed. Diagnostic performance was evaluated by ROC analysis, and microbiota–metabolite correlations.Results Significant differences in oral microbial diversity were observed between MI patients and controls. MI patients exhibited significantly higher alpha diversity and a distinct community structure, with beta diversity separating between groups. Enriched taxa included Bacteroidota, Veillonella, and Prevotella_7, while Streptococcus and Porphyromonas were depleted in MI patients. A four-metabolite panel comprising elevated L-2-aminoadipic acid and reduced thromboxane B2, 4-oxo-2-nonenal, and arginyl-glutamate distinguished MI from controls with high diagnostic accuracy (AUC = 0.92–0.94). Pathway analysis implicated ferroptosis and arginine/proline metabolism as candidate mechanisms. Correlation analysis revealed a significant positive association between Streptococcus and L-2-aminoadipic acid.Conclusion MI is associated with distinct oral microbial and salivary metabolomic signatures. A four-metabolite panel shows promise as a potential non-invasive biomarker signature, though external validation is required. Given the cross-sectional design, causality cannot be established.