Effect of fructooligosaccharide on endothelial function in CKD patients: a randomized controlled trial

Background. Microbiota-derived uremic toxins have been associated with inflammation that could corroborate with endothelial dysfunction (ED) and increase cardiovascular risk in patients with chronic kidney disease (CKD). This trial aimed to evaluate the effect of the prebiotic fructooligosaccharide (FOS) on endothelial function and arterial stiffness in nondialysis CKD patients. Methods. In a double-blind controlled trial, 46 nondiabetic CKD patients were randomized to receive 12 g/day of FOS or placebo (maltodextrin) for 3 months. Total p-cresyl sulfate (PCS) and indoxyl sulfate by high-performance liquid chromatography, urinary trimethylamine N-oxide by mass spectrometry, C-reactive protein, interleukin-6 (IL-6), serum nitric oxide and stroma-derived factor-1 alfa were measured at baseline and at the end of follow-up; endothelial function was assessed through flow-mediated dilatation (FMD) and arterial stiffness by pulse wave velocity (PWV). Results. The mean (+/- standard deviation) age of the study participants was 57.6 +/- 14.4 years, with an estimated glomerular filtration rate of 21.3 +/- 7.3 mL/min/1.73 m(2). During the follow-up, regarding the inflammatory markers and uremic toxins, there was a significant decrease in IL-6 levels (3.4 +/- 2.1 pg/mL versus 2.6 +/- 1.4 pg/mL; P = 0.04) and a trend toward PCS reduction (55.4 +/- 38.1 mg/L versus 43.1 +/- 32.4 mg/L, P = 0.07) only in the prebiotic group. Comparing both groups, there was no difference in FMD and PWV. In an exploratory analysis, including a less severe ED group of patients (FMD >= 2.2% at baseline), FMD remained stable in the prebiotic group, while it decreased in the placebo group (group effect P = 0.135; time effect P = 0.012; interaction P = 0.002). Conclusions. The prebiotic FOS lowered circulating levels of IL-6 in CKD patients and preserved endothelial function only in those with less damaged endothelium. No effect of FOS in arterial stiffness was observed.