Abstract: FR-PO1055
Impact of Fermentable and Viscous Dietary Fiber on Gut-Derived Uremic Toxins in Rats with Progressive CKD
Session Information
- Kidney Nutrition and Metabolism
October 25, 2024 | Location: Exhibit Hall, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Health Maintenance, Nutrition, and Metabolism
- 1500 Health Maintenance, Nutrition, and Metabolism
Authors
- Biruete, Annabel, Purdue University, West Lafayette, Indiana, United States
- O'Neill, Kalisha, Indiana University School of Medicine, Indianapolis, Indiana, United States
- Hill Gallant, Kathleen M., University of Minnesota Twin Cities, Minneapolis, Minnesota, United States
- de Loor, Henriette, Katholieke Universiteit Leuven, Leuven, Flanders, Belgium
- Evenepoel, Pieter, Katholieke Universiteit Leuven, Leuven, Flanders, Belgium
- Chen, Neal X., Indiana University School of Medicine, Indianapolis, Indiana, United States
- Moe, Sharon M., Indiana University School of Medicine, Indianapolis, Indiana, United States
Background
Dietary fiber has been shown to lower gut-derived uremic toxins. However, this effect may depend on the fiber's physicochemical properties. Our goal was to examine the dietary fiber impact based on their fermentability (i.e., metabolized by the gut microbiota) and viscosity (i.e., gel-forming capacity) properties on circulating and urinary microbially-derived uremic toxins in a rat model of progressive CKD.
Methods
22-wk-old Cy/+ male rats (~50% kidney function of normal; CKD hereafter) were randomly assigned to one of four treatments (all 10% w/w; Table 1). Treatments lasted 10 wk and rats were euthanized at 32-33 wk of age (kidney failure; ~15% of normal). During the last week of the study, rats were placed in metabolic cages for 3 days for urine collection. Serum and urine creatinine (Cr) were analyzed using colorimetric assays; indoxyl sulfate, P-cresyl sulfate, and phenyl sulfate were quantified in urine (normalized to Cr) and serum by ultra-performance liquid chromatography-tandem mass spectrometry. One-way ANOVA was used to test the effect of dietary fiber types on outcomes with post-hoc comparisons vs. cellulose.
Results
At 32-33 wk, serum indoxyl sulfate was not different between treatments, but urinary indoxyl sulfate was 2-3 times higher with pectin compared to cellulose (p=0.008). Serum P-cresyl sulfate was lower in the inulin and psyllium groups compared to cellulose (p<0.0001), but urinary P-cresyl sulfate was 7-17 times higher in pectin compared to cellulose (p<0.0001). Serum phenyl sulfate was lower in the psyllium and pectin groups compared to cellulose (p<0.0006), but urinary phenyl sulfate was lower in all groups compared with cellulose (p<0.009). Of note, serum and urine phenyl sulfate concentrations were near zero in the psyllium-treated rats.
Conclusion
Aromatic amino acid-derived uremic toxins were differentially impacted by dietary fiber types in rats with progressive CKD. This suggests that fiber's fermentability and viscosity properties are important to consider in future trials.
Table 1. Treatment groups
| Treatment | Fermentable | Viscous |
| Cellulose | No | No |
| Inulin | Yes | No |
| Psyllium | No | Yes |
| Pectin | Yes | Yes |
Funding
- Other NIH Support