Background: Cardiovascular disease (CVD) is the single biggest contributor to global mortality. CVD encompasses multiple disorders, including atherosclerosis, hypertension, platelet hyperactivity, stroke, hyperlipidemia, and heart failure. In addition to traditional risk factors, the circulating microbiome or the blood microbiome has been analyzed recently in chronic inflammatory diseases, including CVD in humans.Methods: For this review, all relevant original research studies were assessed by searching in electronic databases, including PubMed, Google Scholar, and Web of Science, by using relevant keywords.Results: This review demonstrated that elevated markers of systemic bacterial exposure are associated with noncommunicable diseases, including CVD. Studies have shown that the bacterial DNA sequence found in healthy blood belongs mainly to the Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria phyla. In cardiac events, such as stroke, coronary heart disease, and myocardial infarction, the increased proportion of Proteobacteria and Actinobacteria phyla was found. Lipopolysaccharides are a major component of Proteobacteria, which play a key role in the onset of CVD. Moreover, recently, a study reported the lower cholesterol‐degrading bacteria, including Caulobacterales order and Caulobacteraceae family were both considerably reduced in myocardial infarction.Conclusion: Proteobacteria and Actinobacteria were shown to be independent markers of the risk of CVD. This finding is evidence for the new concept of the role played by blood microbiota dysbiosis in CVD. However, the association between blood microbiota and CVD is still inconsistent. Thus, more deep investigations are required in future to fully understand the role of the bacteria community in causing and preventing CVD.

Increased bacterial translocation in the gut and bloodstream infections are both major comorbidities of heart failure and myocardial infarction (MI). However, the alterations in the microbiome of the blood of patients with MI remain unclear. To test this hypothesis, we conducted this case-control study to explore the microbiota compositions in the blood of Chinese patients with MI. Using high-throughput Illumina HiSeq sequencing targeting the V3–V4 region of the 16S ribosomal RNA (rRNA) gene, the microbiota communities in the blood of 29 patients with MI and 29 healthy controls were examined. In addition, the relationship between the blood microbiome and clinical features of MI was investigated. This study revealed a significant reduction in alpha diversity (Shannon index) in the MI group compared with the healthy controls. Also, a significant difference was detected in the structure and richness between the patients with MI and healthy controls. The members of the phylum Actinobacteria, class Actinobacteria, order Bifdobacteriales, family Bifidobacteriaceae, and genus Bifidobacterium were significantly abundant in the MI group, while the members of the phylum Bacteroidetes, class Bacteroidia, and order Bacteroidales were significantly enriched in the healthy controls (p < 0.05). Moreover, the functional analysis revealed a significant variation between both groups. For instance, the enrichment of genes involved in the metabolism pathways of three amino acids decreased, that is, nucleotide transport and metabolism, coenzyme transport and metabolism, and lipid transport and metabolism, among others. Our study will contribute to a better knowledge of the microbiota of blood, which will further lead to improved MI diagnosis and therapy. Further study is needed to determine the role of the blood microbiota in human health and disease.

Emerging evidence revealed that the blood microbiota plays a role in several non-communicable diseases, including cardiovascular disease. However, the role of circulating microbes in atherosclerosis remains understudied. To test this hypothesis, we performed this study to investigate the microbial profile in the blood of Chines atherosclerosis volunteers. A total of seventy Acute Coronary Syndrome patients, seventy Chronic Coronary Syndrome patients, and seventy healthy individuals were examined using high-throughput Illumina Novaseq targeting the V3-V4 regions of the 16S rRNA gene. The relationship between atherosclerosis and blood microbiome, clinical variables, and their functional pathways were also investigated. Our study observed significantly higher alpha diversity indices (Chao1, p = 0.001, and Shannon, p = 0.004) in the acute coronary syndrome group compared with chronic coronary syndrome and healthy group, although a significantly lower alpha diversity was observed in the chronic coronary syndrome compared to acute coronary syndrome and healthy group. Beta diversity based on principal coordinate analysis demonstrated a major separation among the three groups. In addition, using linear discriminant analysis, a significant distinct taxon such as Actinobacteria _ phylum, and Staphylococcus_ genus in the healthy group; Firmicutes_ phylum, and Lactobacillus_ genus in the chronic coronary syndrome group, and Proteobacteria and Acidobacteriota _ phyla in acute coronary syndrome group were observed among three groups. Clusters of Orthologous Genes grouped and Kyoto Encyclopedia of Genes and Genomes pathways suggested a significant variation among all groups (p &lt; 0.05). The blood microbiota analysis provides potential biomarkers for the detection of coronary syndromes in this population.

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.

Ghee is a traditional Tibetan dairy product with high-fat content, low yield, plasticity, caseation, and rich nutrition. In this study, we analyzed the diversity of microbial communities in yak milk and ghee samples at high and low altitudes, especially the Lactobacillus genus, and further used metabolomic techniques to compare the differences in metabolites in yak ghee at different altitudes. The results showed that the increase in altitude had a significant and generally inhibitory effect on the microbial community diversity in milk ghee, and yak milk at high altitude was abundant in nutrients, which could antagonize the negative impact of increased altitude. Using non-targeted metabolomics, we infer the composition of flavor compounds in ghee: nine kinds of carboxylic acids, 11 kinds of esters, six kinds of ketones, two kinds of alcohols, and four kinds of alkene compounds, among which the key flavor compounds are dl-2-(acetylamino)-3-phenylephrine acid, 1-(4-methoxyphenyl)-2-propanone, sebacic acid, Lysope 18:1, and uracil 1-beta-d-arabinofuranoside. These flavor substances are found in Lactococcus, Lactobacillus, and Streptococcus. With the participation of Lactobacillus, it is synthesized through biosynthesis of alkaloids derived from ornithine, lysine, and nicotine acid and glyoxylate and decarboxylate metabolism, among which Lactococcus plays a key role. In this study, a variety of lactic acid bacteria related to ghee fermentation were screened out, revealing the composition of volatile flavor compounds in Gannan yak milk ghee in the Qinghai–Tibet Plateau and providing a reference for further key volatile flavor compounds and the formation mechanism of flavor compounds.

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.