Urine and Stool Analysis in Kidney Stone Disease

• Bacterial flora in the intestine of patients with kidney stones compared to non-stone forming individuals [ Time Frame: one day of urine and stool collection ] [ Designated as safety issue: No ]
  The objective of this study is to compare the bacterial flora in the intestine of patients with kidney stones compared to non-stone forming individuals. If there are differences between stone forming and non-stone forming individuals in the content of their bacterial flora, these will also be correlated with levels of metabolites found in the urine that are known risk factors of stone disease. Difference in bacterial intestinal flora already exists for patients who are obese compared to non-obese individuals.
  
  

Kidney stones affect up to 10% of the Canadian population and can lead to pain, hospitalization, lost of time at work, and surgery. Approximately 80% of stones consist of calcium and oxalate, of which both components come from diet and normal bodily processes. Individuals who have high levels of oxalate in their urine have a greater tendency to generate stones. One recommendation is to reduce their intake of oxalate-containing foods, but many healthy foods contain oxalate, and an oxalate-free diet is unpalatable and difficult to achieve. Some patients, despite reducing their oxalate intake, still have high amounts in the urine.

Intestinal metabolism is largely affected by the state and composition of the intestinal bacterial flora, with several metabolic diseases being linked to a disrupted "normal" intestinal flora. The investigators believe that calcium oxalate stone disease as well as high urinary levels of oxalate (hyperoxaluria) are triggered by inefficient oxalate metabolism in the intestine, which is linked to a "disrupted" intestinal bacterial flora that lacks certain key components such as O. formigenes. The long-term purpose of this study is therefore, to determine the effect of replenishing the intestinal flora of patients with that of "normal" controls, thereby re-introducing a balanced environment that will lead to the re-establishment of normal metabolic functions and a decrease in urinary oxalate levels and hopefully lower incidence of stone disease.