The link between inflammatory/ SCFA profiles and oral/gut microbiome: an observational study in patients with ST-segment elevation myocardial infarction

Acute myocardial infarction (AMI) is a leading cause of mortality in Mexico. The microbiota plays a crucial role in immune regulation, and its dysbiosis promotes low-grade inflammation, a key contributor to AMI development. This study aimed to compare the oral (OM) and gut microbiota (GM) composition in patients with ST-segment elevation myocardial infarction (STEMI) and healthy controls. Additionally, we explored the interaction between these microbiomes and their correlations with inflammatory profiles and metabolites. In this study, we included 36 STEMI patients and 12 healthy subjects. The composition of both GM and OM was analyzed through 16S sequencing of dental plaque and stool samples. Short-chain fatty acids (SCFAs) were measured via gas chromatography-mass spectrometry, while serum cytokines were assessed using flow cytometry. STEMI patients exhibited significant differences in OM alpha and beta diversity, while GM structure remained unchanged compared to healthy group. Several differentially abundant genera were identified in both OM and GM. Regarding SCFA profiles, Healthy subjects displayed a higher abundance of isovaleric acid, whereas isobutyric and 2-methylbutyric acids were significantly higher in STEMI patients. Moreover, correlations between circulating SCFAs, cytokines, and microbiota composition were observed in both niches. Furthermore, network analysis suggests that oral bacteria, particularly those linked to periodontal disease, can potentially influence GM by interacting with SCFA-producing bacteria. This is the first study in México to comprehensively explore OM and GM in STEMI patients. Our findings highlight the potential for developing preventive strategies against myocardial infarction by exploring both oral and gut microbiomes, as well inflammatory markers and SCFAs.