Dysbiosis promotes recurrence of adenomatous polyps in the distal colorectum

Figure 1 Histologic changes of recurrent distal colorectal polyps. A: Healthy physical examination group. Histology shows normal glands; B: Non-adenomatous polyp group. Histology shows epithelial hyperplasia, no heterogeneous hyperplastic glands, and few inflammatory cells; C: Adenomatous polyp group. Histology shows branched tubular glands. Original magnification × 100 (left) and × 400 (right).

Figure 2 Mucosal microbiome composition and differences between control, patient-0. 5, and patient-10 groups. A: Wayne plots of the total number of species in the three groups at the operational taxonomic unit level showing the composition of the mucosal microbiome in each group. Red represents control mucosa, light blue represents the patient (Pat)-0.5 group, yellow represents the Pat-10 group, and the number of non-overlapping species represents the number of species specific to the corresponding group; B and C: Cumulative percentage histograms of the top 10 bacterial species with the highest abundance at the phylum and genus levels for the three groups; D and E: Differences in mucosal microbiome composition between the control group and the group of patients with recurrent colorectal polyps assessed using principal coordinate analysis and non-metric multidimensional scaling analysis. P values were calculated by the Wilcoxon’s test at the level of the bray distance operational taxonomic unit. Pat: Patient; Con: Control.

Figure 3 Differences in gut bacteria between the mucosa of patients with recurrent colorectal polyps of different pathologic types and the mucosa of controls. A: Bubble plots with different colors showing the affiliation of intestinal genera to the phylum, and the size of the bubbles showing the abundance of the genera; B: Heatmaps of the top 30 different intestinal genera in the control (Con), non-adenomatous polyps (Pol)-0.5, Pol-10, adenomatous polyps (Ade)-0.5, and Ade-10 groups. Colors in the heatmaps are used to depict specific general abundances in the four groups, with blue denoting low abundance and red denoting high abundance; C-F: Sankey diagrams. The Pol-0.5, Pol-10, Ade-0.5, and Ade-10 groups, respectively, are compared to the Con group (left). The Sankey diagrams of the taxonomic data vary with the branching widths of the genera (third row) and phylum (second row). Genera are categorized according to Gram-positive and negative bacteria (right). The color and width of the branches represent the flow of specific genera in different groups, in different phyla, and belonging to different Gram classifications. Ade: Adenomatous polyps; Pol: Non-adenomatous polyps; Con: Control.

Figure 4 Comparison of gut microbiota in the mucosa of patients with recurrent colorectal polyps of different pathologic types with that of controls. A and B: Characteristic analysis of microbiota phenotype in the mucosa around intestinal polyp lesions; C-F: Histogram of the distribution of beneficial and pathogenic bacteria in different groups at genus level (C and E), and heat map of the distribution of beneficial and pathogenic bacteria (D and F). Ade: Adenomatous polyps; Pol: Non-adenomatous polyps; Con: Control.

Figure 5 Comparison of mucosal diversity between normal human distal colorectum and patients with recurrent colorectal polyps of different pathologic types. A: Venn diagram of the total number of species in the five groups at the operational taxonomic unit level; B-F: Comparison of α diversity analysis, richness, evenness, and diversity between five groups. Sob (B), Chao1 (C), ACE (D), Shannon index (E), and Simpson index (F) are compared; G: Plot of principal component analysis of gut microbiome groups based on Wilcoxon test metrics of operational taxonomic unit level bray distance; H: Heatmap of β diversity values based on rank-sum test between two groups. ^bP < 0.01, ^cP < 0.001. Ade: Adenomatous polyps; Pol: Non-adenomatous polyps; Con: Control.

Figure 6 Bar chart of test for multi-species differences between different groups. Student’s t-test was used to evaluate the level of significance of multi-species differences at the genus level. The closer the line is to the middle, the smaller the standard deviation and the better the central tendency. A-D: Results of non-adenomatous polyps (Pol)-0.5, Pol-10, adenomatous polyps (Ade)-0.5, and Ade-10 compared with the control group, respectively; E and F: Results of Pol-0.5 compared with Ade-0.5 and Pol-10 compared with Ade-10, respectively. Ade: Adenomatous polyps; Pol: Non-adenomatous polyps; Con: Control.

Figure 7 Diagram of different bacteria communities. A-L: These plots were derived from the linear discriminant analysis (LDA), which was employed to rank identified species. LDA plots showcase groups of biomarkers, with the bar graph lengths indicating the effect magnitude of these differential species. Only results with LDA scores ≥ 2 and a significance level of ^aP < 0.05 were retained for these visualizations (A, C, E, G, I, and K); the linear discriminant analysis effect size (LEfSe) analysis began with a Kruskal-Wallis rank sum test applied to all group samples, aiming to identify differentially abundant species (^aP < 0.05). Subsequently, these species were compared pairwise between groups using the Wilcoxon rank sum test (B, D, F, H, J, and L). The outcome is an evolutionary branching diagram, which plots these divergent species on a taxonomically structured tree. In this diagram, circles radiate from the inner to the outer layers, representing taxonomic levels from phylum to species. The default display extends to the species level. The circle diameters correspond to the relative abundance of taxa, and different color nodes highlight groups significantly enriched in bacterial bacteria, thus underlining the distinctiveness between groups. Species with non-significant differences are not displayed by default. A and B, C and D, E and F, and G and H represent LDA score and LEfSe analysis of non-adenomatous polyps (Pol)-0.5, Pol-10, adenomatous polyps (Ade)-0.5, and Ade-10 vs Con, respectively; I and J represent LDA score and LEfSe analysis of Pol-0.5 vs Ade-0.5; K and L represent LDA score and LEfSe analysis of Pol-10 vs Ade-10. Ade: Adenomatous polyps; Pol: Non-adenomatous polyps; Con: Control; LDA: Linear discriminant analysis.