Recruiting

Observational Study

Sponsor:

University of Alabama at Birmingham

Code:

NCT06989320

Conditions

Kidney Stones

Kidney Calculi

Urolithiasis

Urolithiasis, Calcium Oxalate

Nephrolithiasis

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Accepted

Interventions

Low-oxalate diet and glycolate dosing

Oral glycolate dosing

Oral 13C- ascorbic acid dosing

Study Details

Brief summary:

The goal of this clinical trial study is to test if patients with idiopathic calcium oxalate kidney stones have an increased production of oxalate by the body, which would lead to increased urinary excretion of oxalate.

The study will recruit adult patients with a history of calcium oxalate kidney stones and healthy volunteers without kidney stones.

Participants will

ingest fixed diets containing low amounts of oxalate for 5 days ingest a soluble form of glycolate and vitamin C collect urine, blood, stool during the dietary and oral dosing portions of the study and also collect breath sample during the oral glycolate test

Conditions

Kidney Stones

Kidney Calculi

Urolithiasis

Urolithiasis, Calcium Oxalate

Nephrolithiasis

Study ID

NCT06989320

Start date

May 27, 2025

Status verified date

Aug, 2026

Completion date

Dec 31, 2031

Anticipated

Primary completion date

Dec 31, 2030

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 70+

Healthy Volunteers: Accepted

Inclusion Criteria:

  • age 18-80 yrs
  • Body Mass Index > 18.5 kg/m2
  • Normal fasting serum electrolytes on comprehensive metabolic profile
  • Willing to ingest fixed diets
  • Willing to stop supplements (vitamins including vitamin C, calcium (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, probiotics) for 2 weeks before start and during study.
  • For stone formers: first time or recurrent Calcium Oxalate stone former. Composition of most recent stone ≥ 50% calcium oxalate if available, uric acid component <20%

Exclusion Criteria:

  • Chronic Kidney Disease stage 4-5
  • Primary hyperoxaluria, Enteric (secondary) hyperoxaluria
  • Liver, bowel, endocrine or renal diseases (other than idiopathic Calcium Oxalate kidney stones) or any other condition that may influence the absorption, transport or urinary excretion of ions, which will compromise the interpretation of results, including: 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 breast-feeding
  • Incompatible dietary requirements with the study, food allergies or intolerance to any of the foods in study menus
  • Active malignancy or treatment for malignancy within 12 months prior to screening
  • Utilization of immunosuppressive medication
  • Uncontrolled hypertension or diabetes
  • Diabetes type 1

Study Design

Enrollment

80 participants

Anticipated

Allocation

Non randomized

Intervention Model

Parallel Assignment

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Idiopathic Calcium Oxalate Kidney Stone Patients

Low oxalate fixed diets. oral glycolate and ascorbic acid administration

active comparator: Healthy non-kidney stone forming individuals

Low oxalate fixed diets. oral glycolate and ascorbic acid administration

Interventions

Low-oxalate diet and glycolate dosing

Low-oxalate diet 4 days of fixed eucaloric diet with low oxalate (<60 mg/day), normal calcium content (600-1000 mg/day)

Oral glycolate dosing

Oral 13C-glycolate dosing (0.5 mg/kg)

Oral 13C- ascorbic acid dosing

Oral 13C- ascorbic acid dosing (0.75 mg/kg)

Primary outcome measure

  • Estimated endogenous oxalate synthesis (oxalate mg/day) [ Time Frame: 1 day ]

Central Contacts and Locations

Central contacts

Sonia Fargue, PhD

205-975-6932sfargue@uabmc.edu

Locations

United States, Alabama University of Alabama at Birmingham

Recruiting

Birmingham, Alabama, United States, 35294

Contacts

Sonia Fargue, PhD

205-975-6932sfargue@uabmc.edu

Research Coordinator

205-934-5712kidneystone@uabmc.edu

Principal Investigator:

Sonia Fargue, PhD

More Information

Sponsor

University of Alabama at Birmingham

Last update posted

Aug 27, 2026

Last verified

Aug, 2026

Keywords

  • oxalate synthesis

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-09. This information was provided to ClinicalTrials.gov by University of Alabama at Birmingham on 2026-08-27.