Background: In almost every country, cardiovascular diseases are the major cause of death, which are responsible for 17.7 million deaths worldwide, or 54% of all deaths. However, the latest evidence has shown that non‐communicable diseases such as obesity, diabetes, and cardiovascular events are significantly influenced by the blood microbiota and circulating metabolites.Methods: We searched online databases for the most recent related papers through the comprehensive international databases of the Institute of PubMed/ MEDLINE, ISI/WOS, and Scopus up to August 2022, using MESH terms and the related keywords in the English language. Considering the titles and abstracts, unrelated studies were excluded. The full texts of the remained studies were evaluated by authors, independently. Then, the studies' findings were assessed and reported.Results: The study demonstrated that the bacterial profiles of patients with cardiovascular diseases and healthy individuals are significantly different. The diseased patients showed a significantly high abundance of phylum Proteobacteria, an important Proteobacterial component known as lipopolysaccharides that has been linked to the pathogenesis of cardiovascular disease, while phylum Firmicutes were found in healthy individuals. It suggests that Proteobacteria has a direct role in the onset of cardiovascular disease.Conclusion: We focused on the blood bacterial composition and circulating microbial metabolites in their relationship with the etiology and onset of cardiovascular disease. However, the various genera and species in the results reported were not always identical. Therefore, the microbial community structure of blood was more complicated and thus required a more in‐depth exploration.

Introduction: The blood microbiome, increasingly recognized as a distinct microbial niche, may originate partly from oral translocation. We systematically compared circulating and oral microbiome profiles between healthy individuals and myocardial infarction (MI) patients to identify disease-associated signatures.Methods: The current study recruited 20 participants, including 10 healthy controls and 10 patients with MI. Blood and Saliva samples were collected from each participant to analyze the association between blood and oral microbiome in MI patients using 16S rRNA gene sequencing.Results: The blood microbiome showed significantly greater alpha diversity than the oral microbiome (p<0.05), but beta diversity did not differ significantly. The blood microbiome in MI patients had higher levels of Firmicutes, Bacteroidota, Actinobacteriota, genus Bacteroides, and lower Proteobacteria, whereas the oral microbiome was dominated by Firmicutes, Bacteroidota, Veillonella, and Prevotella_7. LEfSe analysis revealed distinct blood microbial taxa-Actinobacteria in MI patients and Enterobacterales in controls. In contrast, the oral microbiota of healthy subjects was enriched in Rothia, Micrococcaceae, and Micrococcales, while no distinct taxa were associated with MI. Both blood and oral microbiomes showed significant functional pathway differences (KEGG) between groups. Additionally, microbiome signatures significantly correlated with clinical and demographic markers.Discussion: Our study demonstrates that the blood harbors a distinct microbiome characterized by specific microbial taxa and functional pathways rather than merely reflecting oral bacterial translocation. These findings suggest that the circulating microbiome may play an active role in the pathology of MI. Furthermore, we identified significant associations between these microbial signatures and clinical disease markers. This highlights the potential importance of the blood microbiome in understanding the mechanisms underlying MI and its diagnostic or therapeutic implications.

Introduction: The significance of oral microbiota in acute myocardial infarction (AMI) has been increasingly appreciated. However, the association between oral microbiota, metabolites, and AMI parameters, as well as the key microbiota and metabolites that may play a crucial role in this process, remains unclear. To investigate the oral microbiome composition and metabolomic profiles associated with AMI and explore the roles of specific bacterial species and key metabolites in functional pathways in the progression of AMI.Methods: A case-control study was conducted involving 24 AMI patients and 24 matched healthy controls. Saliva samples were collected for 16S rRNA sequencing and untargeted LC-MS metabolomics. Correlation analysis was then performed to explore associations between microbial taxa, metabolomic profiles, and AMI clinical parameters, with results visualized as heatmaps of correlation coefficients.Results: The component of the oral microbiota of the AMI group showed significant alterations when compared to the control group. Particularly, a significant shift in terms of alpha and beta diversity was observed between the AMI and control groups (p < 0.05). The Streptococcus and Rothia genera, as well as 9(R)-HODE, 20-HETE ethanolamide, and 5,6 EET metabolites, were identified as potential biomarkers, achieving an area under the curve of 0.82–0.88. Functional pathway analysis demonstrated significant upregulation in key metabolic pathways, including the Citrate Cycle (TCA cycle), Pyruvate metabolism, and Glucagon signaling pathways, which exhibited strong correlations with established clinical markers of AMI.Conclusion: This integrative analysis underscores the diagnostic potential of oral microbiome-metabolome interactions in AMI and unveils key mechanistic pathways for guiding future therapeutic interventions.