p-Cresyl sulfate serum concentrations in haemodialysis patients are reduced by the prebiotic oligofructose-enriched inulin

Nephrol Dial Transplant. 2010 Jan;25(1):219-24. doi: 10.1093/ndt/gfp414. Epub 2009 Aug 19.


Introduction: Protein-bound uraemic retention solutes, including p-cresyl sulfate and indoxyl sulfate, contribute substantially to the uraemic syndrome. These and several other uraemic retention solutes originate from intestinal bacterial protein fermentation. We investigated whether the prebiotic oligofructose-enriched inulin reduced serum concentration of p-cresyl sulfate and indoxyl sulfate, through interference with intestinal generation.

Methods: We performed a single centre, non-randomized, open-label phase I/II study in maintenance HD patients with a 4-week, escalating dose regimen of oligofructose-enriched inulin (ORAFTI Synergy 1, Tienen, Belgium) (www.clinicaltrials.gov NCT00695513). Changes in p-cresyl sulfate and indoxyl sulfate serum concentrations as well as changes in p-cresyl sulfate and indoxyl sulfate generation rates were analysed.

Results: Compliance with therapy was excellent. p-Cresyl sulfate serum concentrations at 4 weeks were significantly reduced by 20% (intention to treat, P = 0.01; per protocol, P = 0.03). Also p-cresyl sulfate generation rates were reduced (P = 0.007). In contrast, neither indoxyl sulfate generation rates (P = 0.9) nor serum concentrations (P = 0.4) were significantly changed.

Conclusion: The prebiotic oligofructose-inulin significantly reduced p-cresyl sulfate generation rates and serum concentrations in haemodialysis patients. Whether reduction of p-cresyl sulfate serum concentrations, an independent predictor of cardiovascular disease in HD patients, will result in improved cardiovascular outcomes remains to be proven.

Publication types

  • Clinical Trial, Phase I
  • Clinical Trial, Phase II
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Administration, Oral
  • Aged
  • Cresols / blood*
  • Female
  • Humans
  • Indican / blood
  • Inulin / administration & dosage
  • Inulin / adverse effects
  • Inulin / therapeutic use*
  • Kidney Failure, Chronic / blood
  • Kidney Failure, Chronic / therapy*
  • Male
  • Middle Aged
  • Oligosaccharides / administration & dosage
  • Oligosaccharides / adverse effects
  • Oligosaccharides / therapeutic use*
  • Prebiotics*
  • Renal Dialysis / methods*
  • Sulfuric Acid Esters / blood*


  • Cresols
  • Oligosaccharides
  • Prebiotics
  • Sulfuric Acid Esters
  • oligofructose
  • 4-cresol sulfate
  • Inulin
  • Indican

Associated data

  • ClinicalTrials.gov/NCT00695513