Assessment of Endogenous Oxalate Synthesis
Purpose
This study aims to determine the daily rate of endogenous synthesis of oxalate using carbon 13 oxalate isotope tracer technique and a low-oxalate controlled diet.
Conditions
- Healthy
- Kidney Stone
- Obesity
Eligibility
- Eligible Ages
- Between 18 Years and 75 Years
- Eligible Genders
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- Mentally competent adults, able to read and comprehend the consent form - Body Mass Index (BMI) between 18.5 and 50 kg/m2 - Acceptable 24 hour urine collections (judged on screening) - for non-stone formers, good health as judged from a medical history, reported medications, and a complete blood metabolic profile, baseline urinary oxalate excretion < 40 mg/day - for kidney stone formers: first time or recurrent CaOx stone former with stone event within the prior 3 years. Composition of most recent stone (if known) > 50% calcium oxalate, without uric acid component.
Exclusion Criteria
- History of any hepatic, bowel, or endocrine disease or other condition that may influence the absorption, transport or urine excretion of ions - Abnormal urine chemistries or blood metabolic profiles - Poor 24 hour urine collections completed during screening, judged by 24 hour urine creatinine excretion (indicative of not collecting all urine in the 24 hour period) - Pregnancy, intention to become pregnant in the near future, or lactation - Aged <18 or >75 years - BMI <18.5 or >50 kg/m2
Study Design
- Phase
- N/A
- Study Type
- Interventional
- Allocation
- N/A
- Intervention Model
- Sequential Assignment
- Primary Purpose
- Basic Science
- Masking
- None (Open Label)
Arm Groups
| Arm | Description | Assigned Intervention |
|---|---|---|
|
Experimental Constant infusion of 13C2-oxalate |
Subjects who have passed screening, will consume a low-oxalate, normal calcium controlled diet for 5 days total. On Days 3 and 4, subjects will collect two 24-hour urines. On Day 5, they will receive a carbon 13 oxalate infusion which will occur at a constant rate for 6 hours, in the fasted state, following a priming dose. Hourly urine and twice hourly blood samples will be collected during the 6 hours. Meals will be resumed at the end of the infusion and timed urine collections will take place at home until the next day. A DXA scan will be performed to assess body composition at another date. |
|
Recruiting Locations
University of Alabama at Birmingham
Birmingham, Alabama 35294
Birmingham, Alabama 35294
More Details
- Status
- Recruiting
- Sponsor
- University of Alabama at Birmingham
Detailed Description
Urinary oxalate excretion is derived from both dietary sources and endogenous synthesis. This study will use low-oxalate controlled diet and intravenous infusion of the isotope tracer carbon 13 oxalate, timed with blood and urine collections, to determine the daily rate of endogenous oxalate synthesis in non-stone forming volunteers and in subjects with calcium oxalate kidney stones. A DXA scan will be used to assess body composition.