Colonic dialysis can influence gut flora to protect renal function in patients with pre-dialysis chronic kidney disease

Abstract

Chronic kidney disease (CKD) is a major public health burden around the world. The gut microbiome may contribute to CKD progression and serve as a promising therapeutic target. Colonic dialysis has long been used in China to help remove gut-derived toxins to delay CKD progression. Since disturbances in the gut biome may influence disease progression, we wondered whether colonic dialysis may mitigate the condition by influencing the biome. We compared the gut microbiota, based on 16S rRNA gene sequencing, in fecal samples of 25 patients with CKD (stages 3-5) who were receiving colonic dialysis(group CD), 25 outpatients with CKD not receiving colonic dialysis(group OP), and 34 healthy subjects(group HS). Richness of gut microbiota was similar between patients on colonic dialysis and healthy subjects, and richness in these two groups was significantly higher than that in patients not on colonic dialysis. Colonic dialysis also altered the profile of microbes in the gut of CKD patients, bringing it closer to the profile in healthy subjects. Colonic dialysis may protect renal function in pre-dialysis CKD by mitigating dysbiosis of gut microbiota.

Figure 1

Differences in gut microbiome biodiversity across the two patient groups and one group of healthy controls. The three populations were CKD patients on colonic dialysis (CD, red) or not (OP, blue), as well as healthy controls (HS, green). (A) Gut microbiome profiles at phylum level. (B) The top 50 operational taxonomic units (OTUs) of all samples were used to generate a heat map. The x-axis represents the sample; the y-axis, OTUs. Color shading reflects OTU abundance. (C) Analysis of linear discriminant analysis effect size (LEfSe) was performed on the three groups. The x-axis indicates the linear discriminant analysis (LDA) score; the y-axis, the taxa that help distinguish the three groups from one another. The larger the value is, the greater is the difference. Different colors represent different groups. (D) Cladogram, in which the small circles radiating from the inside to the outside represent the classification level of the species at the level of phylum, class, order, family, and genus. The diameter of the small circle represents relative abundance. The nodes of different colors in the phylogenetic tree are the microbial groups that distinguish the given group from the two others. The closeness and partial overlap of green and red areas in the phylogenetic tree suggest that the intestinal microbiome of CKD patients on colonic dialysis was more similar to that of healthy subjects than to that of patients not on dialysis.

Figure 2

Richness of the gut microbiome in the three groups.The three populations were CKD patients on colonic dialysis (CD) or not (OP), as well as healthy controls (HS). (A) Shannon index of the gut microbiome. (B) Simpson index of the gut microbiome. *p < 0.05 in comparison to HS group or CD group.

Figure 3

Effects of colonic dialysis on CKD-induced imbalance of the gut microbiome. OTU operational taxonomic unit.