Abstract
BACKGROUND: Coronary heart disease (CHD) is the leading cause of death and disability worldwide. The human microbiota, particularly gut bacteria, plays a role in the development of CHD. However, determining the contribution of gut bacteria translocation to systemic circulation in the progression of atherosclerosis remains challenging. METHODS AND RESULTS: In this exploratory study, we conducted 16S rRNA-based metagenomic analysis to characterize systemic bacterial profiles in a cohort of 27 patients with CHD (9 with severe coronary artery stenosis and 18 with mild to moderate stenosis). We compared microbial diversity between arterial and venous blood and across different blood fractions. For the first time, we observed higher microbial diversity in plasma than in serum. We also identified differences in microbial richness among arterial whole blood, venous whole blood, arterial plasma, venous plasma, arterial serum, and venous serum, with 15, 22, 43, 10, 4, and 3 genera showing significant differences, respectively. Many of the detected blood taxa belonged to genera typically found in intestinal, oral, or skin microbiota, although their precise source cannot be determined from this study. CONCLUSIONS: Our study provides preliminary evidence of distinct bacterial profiles between arterial and venous blood fractions in patients with CHD, as determined by 16S rRNA sequencing. These findings should be interpreted with caution given the small sample size and the absence of a healthy control group, and they warrant confirmation in larger, controlled studies.