NCT06330246

O. Formigenes Colonization in Calcium Oxalate Kidney Stone Disease

Oxalobacter Formigenes Colonization in Calcium Oxalate Kidney Stone Formers

• Status: Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 40 (estimated)
• Sponsor: University of Alabama at Birmingham · Academic / Other
• Sex: All
• Age: 18 Years – 70 Years
• Healthy volunteers: Not accepted

Summary

The goal of this trial is to test if colonization with the gut bacteria Oxalobacter formigenes leads to a reduction in urinary oxalate excretion in patients with calcium oxalate kidney stone disease. The study will recruit adult participants with a history of calcium oxalate kidney stones who are not colonized with Oxalobacter formigenes. Participants will * ingest fixed diets containing low and moderately high amounts of oxalate for 4 days at a time * collect urine, blood and stool samples during the fixed diets * ingest a preparation of live Oxalobacter formigenes to induce colonization with Oxalobacter formigenes

Detailed description

In this study the investigators propose to measure the excretion of urinary oxalate on a fixed diet with controlled amounts of oxalate, before and after inducing colonization with the gut bacteria Oxalobacter formigenes in individuals with a history of calcium oxalate kidney stones not already colonized with Oxalobacter formigenes. Screening and Pre-colonization phase. Between the University of Alabama at Birmingham (UAB) and the University of Texas Southwestern Medical Center (UTSW), the study will enroll 40 individuals with a history of idiopathic calcium oxalate kidney (20 males/20 females). Screening will include stool colonization testing, blood complete metabolic profile, 24-hr urine specimens collected at home on self-selected diets and anthropometric measurements. Participants will ingest a low-oxalate (\<60 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning. After a wash-out period of at least 1 week, participants will ingest a moderately high-oxalate (250-300 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning. Colonization and Post-colonization phase. Participants will be colonized with Oxalobacter formigenes by ingesting a freshly thawed paste of live bacterial preparation of O. formigenes. They will collect a stool sample 1 week later to assess if colonization occured. After confirmation of successful colonization, participants will ingest a low-oxalate (\<60 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning. After a wash-out period of at least 1 week, participants will ingest a moderately high-oxalate (250-300 mg/day) fixed diet for 4 consecutive days and collect two 24-hr urines and a stool sample after 2 days of dietary equilibration, as well as one fasted blood sample on the last morning. Follow-up phase Participants will be followed up every 6 months to assess sustainability of colonization, provide a stool sample and answer a simple questionnaire. A 24-hr urine collection will be requested once a year after colonization, on the same moderately high oxalate diet diet after 2 days of dietary equilibration.

Conditions

• Kidney Stone
• Kidney Calculi
• Urolithiasis
• Urolithiasis, Calcium Oxalate
• Nephrolithiasis
• Nephrolithiasis, Calcium Oxalate
• Oxalate Urolithiasis
• Oxaluria

Interventions

Type	Name	Description
DIETARY_SUPPLEMENT	Low oxalate fixed diets pre-colonization	4 days of fixed eucaloric diet with low oxalate (\< 60 mg/day), normal calcium (600-1000 mg/day)
DIETARY_SUPPLEMENT	Moderately high oxalate fixed diets pre-colonization	4 days of fixed eucaloric diet with moderately high oxalate (250-300 mg/day), normal calcium (600-1000 mg/day)
DIETARY_SUPPLEMENT	Colonization with Oxalobacter formigenes	Ingestion of live Oxalobacter formigenes
DIETARY_SUPPLEMENT	Low oxalate fixed diets post-colonization	4 days of fixed eucaloric diet with low oxalate (\< 60 mg/day), normal calcium (600-1000 mg/day)
DIETARY_SUPPLEMENT	Moderately high oxalate fixed diets post-colonization	4 days of fixed eucaloric diet with moderately high oxalate (250-300 mg/day), normal calcium (600-1000 mg/day)

Timeline

• Start date: 2024-04-17
• Primary completion: 2030-12-31
• Completion: 2031-12-31
• First posted: 2024-03-26
• Last updated: 2025-05-13

Locations

2 sites across 1 country: United States