Effects of Fecal Microbiota Transplantation on Composition in Mice with CKD

Abstract

Background: Chronic kidney disease (CKD) is a renal disorder characterized by the accumulation of uremic toxins with limited strategies to reduce their concentrations. A large amount of data supports the pivotal role of intestinal microbiota in CKD complications and as a major source of uremic toxins production. Here, we explored whether fecal microbiota transplantation (FMT) could be attenuated in metabolic complication and uremic toxin accumulation in mice with CKD.

Methods: Kidney failure was chemically induced by a diet containing 0.25% (w/w) of adenine for four weeks. Mice were randomized into three groups: control, CKD and CKD + FMT groups. After four weeks, CKD mice underwent fecal microbiota transplantation (FMT) from healthy mice or phosphate buffered saline as control. The gut microbiota structure, uremic toxins plasmatic concentrations, and metabolic profiles were explored three weeks after transplantation.

Results: Associated with the increase of alpha diversity, we observed a noticeable improvement of gut microbiota disturbance, after FMT treatment. FMT further decreased p-cresyl sulfate accumulation and improved glucose tolerance. There was no change in kidney function.

Conclusions: These data indicate that FMT limited the accumulation of uremic toxins issued from intestinal cresol pathway by a beneficial effect on gut microbiota diversity. Further studies are needed to investigate the FMT efficiency, the timing and feces amount for the transplantation before, to become a therapeutic option in CKD patients.

Keywords: chronic kidney disease; fecal microbiota transplantation; p-cresyl-sulfate; uremic toxins.

Figure 1

Body weight evolution and food intake, plasma glucose levels during glucose tolerance test. (A) Body weight evolution; Note that arrows indicate the sessions of fecal microbiota transplantation (FMT). (B) Daily food intake; (C) Blood glucose measured and (D) AUC during an i.p. glucose tolerance test (i.p.GTT, 1 g/kg D-glucose) in chronic kidney disease (CKD), CKD-FMT and control mice. * p < 0.05, *** p < 0.001 vs. CKD group; n = 9–10. (One-way ANOVA). Data are expressed as mean ± SEM for n = 9–10 in each group. Abbreviation: AUC: air under curve, FMT, fecal microbiota transplantation, ns: not significant.

Figure 2

Effect of FMT on plasma levels of microbiota-derived uremic toxins. Plasma levels of p-cresyl sulfate (A), p-cresyl glucuronide (B), indole-3-acetic acid (C), indoxyl sulfate (D), hippuric acid (E) and uric acid (F). n = 9–10. vs. CKD group (ANOVA). Data are expressed as mean ± SEM for n = 9–10 in each group. Note that p-cresyl sulfate, p-cresyl glucuronide, indole-3-acetic acid and indoxyl sulfate are derived from gut microbiota, while hippuric acid and uric acid are produced by the host. Differences were considered to be significant at the p < 0.05 level (one-way ANOVA). Abbreviation: ns: not significant.

Figure 3

Effect of FMT on intestinal microbiota (A) Principal component analysis (PCA) of intestinal microbiota derived from CKD (blue dots), CKD + FMT-treated (orange dots) and control (green dots) mice. (B) Alfa diversity evaluated by the Shannon index. The Wilcoxon rank sum test was used to determine significance in α-diversity. Relative abundance of microbiota based on the average number of each subfamily at the phylum (C), and genus levels (D). (E) Heat map of the fold change of the indicated bacterial classes and families compare to control mice (F,G) The percentage of change in each subgroup at the genus level that significantly changed following FMT therapy. n = 4–5. * p < 0.05, vs. CKD group. (One-way ANOVA).

Figure 4

Experimental design of the study. C57BL/6J mice were fed with an adenine diet 0.25% for 4 weeks to induce chronic kidney disease (CKD). After 3 weeks of washout, mice were divided into 3 subgroups to receive either fecal microbiota transplantation (FMT) from control mice every week by oral gavage or Phosphate-Buffered Saline (PBS; referred to as control FMT) until terminal sacrifice after 3 weeks. Control group received only PBS.