Loss of diurnal oscillatory rhythms in gut microbiota correlates with progression of atherosclerosis

Circadian rhythms in gut microbiota composition are crucial for metabolic function and disease progression, yet the diurnal oscillation patterns of gut microbiota in atherosclerotic cardiovascular disease (ASCVD) and their role in disease progression remain unknown. Here, we investigated gut bacterial dynamics in <i>Apoe</i>^-/- mice over 24 hours and elucidated dynamic changes in fecal microbiota composition and function among C57BL/6 and <i>Apoe</i>^-/- mice with standard chow diet or high-fat/high-cholesterol diet under <i>ad libitum</i> conditions. Compared with C57BL/6 mice, <i>Apoe</i>^-/- mice exhibited significant differences in fecal microbial composition. Rhythmicity analysis revealed that the temporal dynamics of fecal microbiota composition and function in <i>Apoe</i>^-/- mice differed significantly from those in C57BL/6 mice, particularly in <i>B. coccoides</i>-dominated oscillatory modules. Functional annotation showed that rhythmic <i>B. coccoides</i> strains inhibited ASCVD progression by enhancing intestinal and endothelial barrier functions. These findings demonstrate that diurnal oscillations in gut microbiota are closely associated with ASCVD progression and provide new insights for microbiota-targeted precision therapies.