Study of the Gut-Kidney Connection in Enteric Hyperoxaluria and Effects of Moderate Oxalate Diet on Urinary Oxalate

What this Trial Is About

Researchers are investigating the gut-kidney connection in people with enteric hyperoxaluria, a condition linked to kidney stones and related to inflammatory bowel disease IBD or Roux-en-Y gastric bypass RYGB surgery. The study will compare 40 participants with these conditions to 40 healthy controls to understand how the gut microbiome affects urinary oxalate levels. This prospective clinical study is sponsored by NYU Langone Health and focuses on how diet influences oxalate metabolism in these groups. Participants will follow a controlled diet with moderately high oxalate content for specific periods Days 0-3 and 21-24 and consume sodium oxalate via prepared spinach from Days 8-20. There is a washout period on Days 4-7 where participants eat ad-lib diets supplemented with daily spinach. The diets are carefully controlled for protein, fat, carbohydrate, calcium, oxalate, ascorbic acid, and fiber. During the study, hydration is maintained by providing bottled water daily. Participants will provide multiple biological samples including four stool collections, four 24-hour urine collections, and two blood samples. Colonic permeability will also be tested four times. The main measurements are urinary oxalate levels on Days 2-3 and 23-24. Additional measurements include fecal oxalate, urinary calcium, sucralose, calcium oxalate supersaturation, and plasma oxalate levels at various time points. The study will help clarify the impact of diet and microbiome on oxalate metabolism over the study period.

Gut Kidney Axis in Enteric Hyperoxaluria