title: Probiotics for prevention of urinary stones.
abstract: BACKGROUND
  Urinary supersaturation is one key determinant of calcium oxalate (CaOx) urinary stone formation, and urinary excretions of oxalate and citrate are two key determinants. Each is influenced by gastrointestinal processes.
  
  
  METHODS
  Open label and randomized placebo studies have examined the effect of oral probiotic preparations on urinary supersaturation and oxalate excretion. Cross sectional studies in humans have studied the association ofOxalobacter formigenescolonization status and urinary oxalate excretion and prevalence of urinary stones. The intestinal microbiome of representative animals adapted to a high oxalate diet has been defined.
  
  
  RESULTS
  The fecal content ofO. formigenes, the best studied oxalate-degrader, varies depending on stone status. However, trials with probiotics designed to degrade oxalate including those containingO. formigenes,Lactobacillus, and/orBifidobacterium spp., have been disappointing. Multiple intestinal segments of animals on a high oxalate diet contains diverse communities of microorganisms that can function together to degrade and detoxify a large oxalate load.
  
  
  CONCLUSIONS
  Although the intestinal microbiome seems likely to play a role to modify gastrointestinal absorption of lithogenic substances and hence urinary stone risk, whether we can develop tools to manipulate it and decrease this kidney stone risk remains to be determined.
authors.affiliation: Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: John C
authors.initials: JC
authors.lastname: Lieske
keywords: Calcium oxalate (CaOx); Lactobacilli; Oxalobacter formigenes; microbiome; nephrolithiasis