Assessment of Endogenous Oxalate Synthesis

The University of Alabama at Birmingham

Status: Completed

Conditions: Healthy; Kidney Stone; Obesity

Treatments: Dietary Supplement: Low-oxalate controlled diet; Other: Primed, continuous intravenous infusion of 13C2-oxalate

Study type: Interventional

Funder types: Other

Identifiers

NCT05229952

IRB151020005-OXI

Details and patient eligibility

About

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.

Full 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.

Enrollment: 23 patients

Sex: All

Ages: 18 to 75 years old

Volunteers: Accepts Healthy Volunteers

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)
• good health as judged from a medical history, reported medications, and a complete blood metabolic profile
• with or without history of calcium oxalate kidney stones

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 lower than 18 or greater than 75 years
• BMI lower than18.5 or greater than 50 kg/m2

Trial design

Primary purpose: Basic Science

Allocation: N/A

Interventional model: Sequential Assignment

Masking: None (Open label)

---

23 participants in 1 patient group

Constant infusion of 13C2-oxalate

Experimental group

Description:

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.

Treatment:

Other: Primed, continuous intravenous infusion of 13C2-oxalate

Dietary Supplement: Low-oxalate controlled diet