Dietary Oxalate and Innate Immunity in Kidney Stone Disease

Not Applicable

Active, not recruiting

• Conditions: Kidney Stone
• Interventions: Dietary Supplement: Low Oxalate Diet; Dietary Supplement: High Oxalate Diet

• Registration Number: NCT04051346
• Lead Sponsor: University of Alabama at Birmingham

Brief Summary

This study will test whether oxalate stimulates urinary crystals and impacts the immune system in healthy subjects using two controlled diets (low and high oxalate).

Detailed Description

Oxalate is a small molecule found in plants and plant-derived food. It has been shown that meals containing high amounts of oxalate can increase urinary oxalate excretion, which is a risk factor for calcium oxalate kidney stones (CaOx KS). Small increases in oxalate can stimulate urinary crystals to form which can elicit an immune response. This study consists of having healthy subjects consume both low and oxalate enriched diets to evaluate the effect of oxalate on urinary crystals and immune responses. Participants will receive a low or high oxalate diet for 4 days prior to having a wash out period for 6 days. Participants will then crossover to the opposite oxalate diet for four more days.

Study Timeline

• Study First Submitted: 2019-08-01
• Study First Submitted QC: 2019-08-07
• Study First Posted: 2019-08-09
• Study Start: 2021-03-05
• Status Verified: 2024-05
• Last Update Submitted: 2024-05-06
• Last Update Posted: 2024-05-08
• Primary Completion: 2025-05-01
• Study Completion: 2025-05-01

Recruitment & Eligibility

• Status: ACTIVE_NOT_RECRUITING
• Sex: All
• Target Recruitment: 20

Inclusion Criteria

• Healthy subjects (men and women) between the ages of 18 and 60 years of age
• No calcium oxalate kidney stones or other medical conditions
• Normal comprehensive metabolic panel (CMP)
• Non tobacco users
• Not pregnant
• BMI between 20-30 kg/m2
• Willing to abstain from vigorous exercise and vitamins/supplements during the study
• Willing to consume only provided diets, accurately collect 24-hour urine samples, and have blood drawn

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Exclusion Criteria

• Inability to sign and read the informed consent
• Any medical, psychiatric, or social conditions that would prohibit participants from abiding by the study requirements
• Physician refusal
• Pregnant women
• Active medical problems
• History of kidney stones or any medical condition that could influence absorption or excretion of oxalate
• Tobacco users
• Taking medications or dietary supplements
• BMI >30 or <20

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Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Low Oxalate Diet Followed by High Oxalate Diet	High Oxalate Diet	Subjects will consume a low oxalate diet for four days, with blood and 24-hour urine collections occurring at baseline and post diet. A ten day wash out period will follow, during which the subject will consume a self-selected diet. Subjects will then consume the high oxalate diet for the final four days, with blood and 24-hour urine collections once again occurring at baseline and post diet.
High Oxalate Diet Followed by Low Oxalate Diet	Low Oxalate Diet	Subjects will consume a high oxalate diet for four days, with blood and 24-hour urine collections occurring at baseline and post diet. A ten day wash out period will follow, during which the subject will consume a self-selected diet. Subjects will then consume the low oxalate diet for the final four days, with blood and 24-hour urine collections once again occurring at baseline and post diet.
High Oxalate Diet Followed by Low Oxalate Diet	High Oxalate Diet	Subjects will consume a high oxalate diet for four days, with blood and 24-hour urine collections occurring at baseline and post diet. A ten day wash out period will follow, during which the subject will consume a self-selected diet. Subjects will then consume the low oxalate diet for the final four days, with blood and 24-hour urine collections once again occurring at baseline and post diet.
Low Oxalate Diet Followed by High Oxalate Diet	Low Oxalate Diet	Subjects will consume a low oxalate diet for four days, with blood and 24-hour urine collections occurring at baseline and post diet. A ten day wash out period will follow, during which the subject will consume a self-selected diet. Subjects will then consume the high oxalate diet for the final four days, with blood and 24-hour urine collections once again occurring at baseline and post diet.

Primary Outcome Measures

Name	Time	Method
Change in Urinary Oxalate	Days 3-4 and 13-14	Twenty-four hour urinary oxalate will be reported as mg/day.
Change in Crystalluria	Days 3-4 and 13-14	Crystalluria will be reported as particles/ml.
Change in Monocyte Subtypes	Days 1, 4, 11, and 14	Monocyte subtypes will be determined using flow cytometry (mean fluorescence intensity).
Change in Monocyte Cellular Energetics and Mitochondrial Function	Days 1, 4, 11, and 14	Cellular energetics and mitochondrial function will be reported as oxygen consumption rate (pmol/min/10,000 cells).
Change in Monocyte Transcriptomics	Days 1, 4, 11, and 14	Monocyte cellular transcriptomics will be determined using RNA sequencing (mRNA).

Trial Locations

Locations (1)

University of Alabama at Birmingham; 🇺🇸 Birmingham, Alabama, United States