The causal relationship between gut microbiota and lipid metabolism in heart failure: A 2-sample Mendelian randomization study

Figure 1.. Mendelian randomization framework linking GM, lipid metabolites, and HF. Genetic instruments for GM and heart failure were obtained from the GWAS catalog; lipid metabolite data were from the FinnGen Consortium. SNPs were selected based on clumping and quality filters. The analysis assessed the direct and mediated effects using MR, including heterogeneity, pleiotropy, and MR-PRESSO tests. GM = gut microbiota, GWAS = genome-wide association studies, HF = heart failure, MR = Mendelian randomization, SNPs = single nucleotide polymorphisms.

Figure 2.. Volcano plot of Mendelian randomization results for GM and heart failure. The plot displays the log₂-transformed odds ratios (x-axis) and–log₁₀ (P-values) (y-axis) for the associations between specific gut bacterial taxa and heart failure risk. Each point represents a bacterial trait. Gray dots indicate nonsignificant associations; orange dots indicate suggestive associations. GM = gut microbiota.

Figure 3.. Volcano plot of associations between lipid metabolites and heart failure. This plot visualizes the Mendelian randomization results for 179 lipid metabolites tested as potential mediators of heart failure. The x-axis shows log2 (OR), and the y-axis shows–log₁₀ (P-value). Orange dots highlight suggestive associations.

Figure 4.. Significant associations between GM and lipid metabolites. This bar plot shows the effect sizes (b) and P-values for significant associations between gut microbial taxa and specific lipid metabolites. These associations were identified as potential mediators in the causal pathway from GM to heart failure. The color gradient represents the direction and magnitude of effect sizes. GM = gut microbiota.

Figure 5.. Indirect effect ratios of GM on heart failure mediated by lipid metabolites. This bar plot illustrates the proportion of the effect of specific gut microbial taxa on heart failure that is mediated through individual lipid metabolites. Positive and negative values indicate the direction of the mediation effect. GM = gut microbiota.