Actively Recruiting
Endogenous Oxalate Synthesis in Idiopathic Calcium Oxalate Kidney Stone Formers
Led by University of Alabama at Birmingham · Updated on 2026-05-29
80
Participants Needed
2
Research Sites
52 weeks
Total Duration
On this page
Sponsors
U
University of Alabama at Birmingham
Lead Sponsor
U
University of Texas, Southwestern Medical Center at Dallas
Collaborating Sponsor
AI-Summary
What this Trial Is About
Researchers are studying idiopathic calcium oxalate kidney stone disease to understand if patients produce more oxalate within their bodies, leading to higher urinary oxalate levels. The study compares adults with a history of calcium oxalate kidney stones to healthy volunteers without stones. This research aims to evaluate oxalate production and the role of vitamin C and glycolate metabolism in these patients using controlled diets and oral dosing tests. Participants will follow a low-oxalate fixed diet (under 60 mg/day) with normal calcium intake for 5 days. They will then take oral doses of 13C-glycolate and 13C-ascorbic acid on separate visits while continuing the diet. Urine, blood, stool, and breath samples will be collected during these dosing tests over several hours. The study includes screening, dietary equilibration, and oral dosing phases. During the study, participants will collect 24-hour urine samples at home and provide blood and breath samples in the research unit. Researchers will monitor urinary oxalate excretion, endogenous oxalate production, and the contribution of vitamin C breakdown to oxalate levels. The total participation involves multiple visits with dietary control, sample collections, and metabolic tests to assess oxalate synthesis and metabolism.
CONDITIONS
Brief Title
Endogenous Oxalate Synthesis in Idiopathic Calcium Oxalate Kidney Stone Disease
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Age 18 to 80 years
- Body Mass Index greater than 18.5 kg/m2
- Normal fasting serum electrolytes on comprehensive metabolic profile
- Willingness to ingest fixed low-oxalate diets
- Willingness to stop taking vitamins, calcium supplements, herbal supplements, nutritional aids, probiotics for 2 weeks before and during the study
- For stone formers: first time or recurrent calcium oxalate kidney stone with most recent stone composition at least 50% calcium oxalate and less than 20% uric acid component if available
You will not qualify if you...
- Chronic Kidney Disease stage 4 or 5
- Primary or secondary hyperoxaluria
- Liver, bowel, endocrine, or renal diseases other than idiopathic calcium oxalate kidney stones that affect ion absorption or excretion
- Conditions such as cystic fibrosis, celiac disease, cystinuria, uric acid stone former, nephrotic syndrome, sarcoidosis, renal tubular acidosis, primary hyperparathyroidism, neurogenic bladder, urinary diversion, chronic diarrhea, bariatric surgery, inflammatory bowel disease
- Pregnancy or breastfeeding
- Incompatible dietary requirements, food allergies, or intolerance to study foods
- Active cancer or cancer treatment within 12 months before screening
- Use of immunosuppressive medication
- Uncontrolled hypertension or diabetes
- Type 1 diabetes
AI-Screening
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Your Study Journey
Duration - 2 to 4 weeks
Participants are screened for eligibility to participate in the trial.
Duration - 5 days
Participants follow a controlled low-oxalate diet for 5 consecutive days and collect urine samples to measure oxalate excretion after dietary equilibration.
2 home urine collections during low-oxalate diet
Duration - 1 day
Participants undergo an oral 13C-glycolate dosing test with blood, urine, and breath samples collected hourly over 7 hours in the research unit, followed by 24-hour urine collection at home while continuing the low-oxalate diet.
1 in-person visit with hourly sampling over 7 hours, plus 24-hour urine collection at home
Duration - 2 days
Participants ingest an oral 13C-ascorbic acid dose after an overnight fast and provide blood and urine samples the next day during a 7-hour collection period in the research unit while continuing the low-oxalate diet.
2 in-person visits with hourly sampling over 7 hours on the second day
Trial Site Locations
Total: 2 locations
1
United States, Alabama University of Alabama at Birmingham
Birmingham, Alabama, United States, 35294
Actively Recruiting
2
University of Texas South Western Medical Center
Dallas, Texas, United States, 75390
Not Yet Recruiting
Research Team
S
Sonia Fargue, PhD
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NON_RANDOMIZED
Model
PARALLEL
Primary Purpose
BASIC_SCIENCE
Number of Arms
2
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