Gut microbiota signatures in subclinical atherosclerosis: links to lipid metabolism and cardiovascular risk modulation

Abstract While conventional risk factors have been extensively studied, there is growing interest in exploring unconventional contributors to cardiovascular diseases (CVDs). The gut microbiota has emerged as a compelling area of investigation. Improving our understanding of the gut microbiota's role in cardiovascular events is crucial for advancing current risk stratification strategies. This study analyzed data from the CV-PREVITAL study, a multicentre, prospective, open-label interventional RCT designed to compare the effectiveness of an educational mobile health intervention versus usual care in reducing CV risk in Italian patients, over the age of 45. For our purpose, our local cohort enrolled 1043 subjects. Data collected included: a) clinical assessments (traditional risk factors, Doppler ultrasound of carotid and femoral arteries, detailed medical history); b) Pittsburgh Sleep Quality Index (PSQI), to assess sleep disturbances; occupational status and standardized dietary and physical activity questionnaires to evaluate lifestyle factors. c) Alpha and Beta diversity analysis was performed in 500 subjects of this population and adjusted for all variables that may influence microbiota composition: the taxonomic composition was analyzed with MetaPhlAn 4, while HUMAnN 3.9 was used to process all samples. 652 species-level genome bins were identified, along with 3,384,536 UniRef90 gene families and 523 metabolic pathways. Alpha diversity was evaluated based on SGB richness, Shannon and Simpson indices. Beta diversity was assessed using Bray-Curtis and Jaccard distances. Alpha diversity analysis revealed no significant differences between patients with or without subclinical atherosclerosis(ASCVD). Beta diversity analysis identified a small but significant separation. Specifically, Oscillibacter sp. ER4, the unidentified SGB6276, and Anaerostipes hadrus were positively correlated with the absence of ASCVD, whereas an unidentified Parasutterella, Hydrogeniiclostridium mannosilyticum, and the unidentified SGB14888 were significantly associated with the presence of subclinical ASCVD.We further investigated the correlations between Oscillibacter spp., cholesterol, and triglycerides using Spearman’s rank correlation analysis. No significant associations were observed with cholesterol. However, Oscillibacter sp. ER4 (r =-0.12), O. valericigenes (r =-0.15), and Oscillibacter sp. MSJ 31 (r = -0.16) exhibited a significant negative correlation with triglyceride levels.Conversely, a subspecies of O. valericigenes showed a significant positive correlation (r =0.09). Our findings indicate Oscillibacter sp. and Anaerostipes hadrus as beneficial bacteria closely associated with the absence of subclinical ASCVD.Notably, certain Oscillibacter subspecies influence blood triglyceride levels, suggesting a modulatory effect.These results highlight the potential role of specific microbial communities in shaping lipid metabolism and regulating cardiovascular risk factors.