Oxalate-Driven Host Responses in Kidney Stone Disease

Study Overview
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Brief Summary
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This study is looking to understand the role of oxalate on kidney stone development and immunity. This study will enroll healthy participants and participants with calcium oxalate kidney stones (CaOx KS). Participants will be in this study for about 3 weeks, consume controlled diets, and provide blood and urine specimens.

Detailed Description
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The purpose of this longitudinal study is to examine the effects of dietary oxalate on nanocrystalluria and the immune system. 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 and patients with CaOx KS 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.

Official Title
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Oxalate-Driven Host Responses in Kidney Stone Disease

Conditions
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Kidney Stones

Intervention / Treatment
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* Dietary Supplement: Low Oxalate Diet
* Dietary Supplement: High Oxalate Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Men and women between the ages of 18 and 60 years old. Able to provide informed consent. BMI between 20-30 kg/m2. Non-tobacco users or not pregnant/breastfeeding/nursing. Normal fasting blood comprehensive metabolic panel, complete blood count, C-reactive protein, and urinalysis. Must accurately collect two 24-hour urine collections within 20% of the appropriate ratio of creatinine (mg)/body weight (kg) for respective gender. Healthy subjects: No history of CaOx KS or other medical conditions. Patients with CaOx KS: Recent stone composition > 50% CaOx; no uric acid, struvite, or carbonate apatite stone content. Must be first-time or recurrent CaOx stone former (last stone event ≤ 3 years). Willing to not consume supplements (i.e. vitamins, Ca (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, and probiotics) for 2 weeks before the study and during the study. Willing to abstain from vigorous exercise during the study as this may compromise immune function. Willing to consume diets provided only by the UAB CCTS Bionutrition Core. No food allergies or intolerance to any of the foods on the study menus. Willing to accurately collect 24-hour urine samples, and to have blood drawn throughout the study. If on medications for KS prevention (e.g. thiazides, citrate supplementation excluding calcium citrate), patients must be on a stable dose regimen for at least 8 weeks prior to and during screening, with no changes in dosing anticipated during the study. Patients should not take allopurinol for 2 weeks prior to screening since allopurinol has antioxidant properties. Exclusion Criteria: Failure to meet the inclusion criteria or physician refusal. Inability to sign and read the informed consent. Any medical, psychiatric, or social conditions that would prohibit participants from abiding by the study requirements. BMI ˃30 kg/m2 and <20 kg/m2 Tobacco users or pregnant or breastfeeding/nursing women. Abnormal fasting blood comprehensive metabolic panel, complete blood count, C-reactive protein, and urinalysis. Inaccurate 24-hour urine collections. Healthy subjects: Currently taking or have recently taken medications within the last 3 months (i.e. antibiotics) or dietary supplements. History of KS or any medical condition that could influence absorption or excretion of oxalate. Active illness including COVID-19, flu, common cold, fever, diarrhea, urinary tract infections, or other infections 14 days before the study and throughout the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy Participants<br>Healthy participants will randomly receive either high (250mg) or low (40mg) oxalate diet for for four days, a ten day washout period on a self-selected diet, and finally the opposite diet from the first for the last four days. | Dietary Supplement: Low Oxalate Diet<br>* Participants will consume a diet that is controlled in its daily contents of oxalate and calcium, and in its content of carbohydrate, fat, and protein. Participants will be asked not to take any dietary supplements, exercise strenuously, or consume food or drink that is not provided to them.<br>Dietary Supplement: High Oxalate Diet<br>* Participants will consume a diet that is controlled in its daily contents of oxalate and calcium, and in its content of carbohydrate, fat, and protein. Participants will be asked not to take any dietary supplements, exercise strenuously, or consume food or drink that is not provided to them.<br>|
| Experimental: Calcium Oxalate Kidney Stone<br>Calcium oxalate kidney stone participants will randomly receive either high (250mg) or low (40mg) oxalate diet for for four days, a ten day washout period on a self-selected diet, and finally the opposite diet from the first for the last four days. | Dietary Supplement: Low Oxalate Diet<br>* Participants will consume a diet that is controlled in its daily contents of oxalate and calcium, and in its content of carbohydrate, fat, and protein. Participants will be asked not to take any dietary supplements, exercise strenuously, or consume food or drink that is not provided to them.<br>Dietary Supplement: High Oxalate Diet<br>* Participants will consume a diet that is controlled in its daily contents of oxalate and calcium, and in its content of carbohydrate, fat, and protein. Participants will be asked not to take any dietary supplements, exercise strenuously, or consume food or drink that is not provided to them.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in Urinary Oxalate | Twenty-four hour urinary oxalate will be reported as mg/day. | Days 3-4 and 13-14 | 
| Change in Nanocystalluria | Nanocrystalluria will be reported as particles/ml. | Days 3-4 and 13-14 | 
| Monocyte Cellular Bioenergetics and Mitochondrial Function | Cellular bioenergetics and mitochondrial function will be reported as oxygen consumption rate (pmol/min/10,000 cells). | Day 1 | 
| Monocyte Cellular Bioenergetics and Mitochondrial Function | Cellular bioenergetics and mitochondrial function will be reported as oxygen consumption rate (pmol/min/10,000 cells). | Day 4 | 
| Monocyte Cellular Bioenergetics and Mitochondrial Function | Cellular bioenergetics and mitochondrial function will be reported as oxygen consumption rate (pmol/min/10,000 cells). | Day 11 | 
| Monocyte Cellular Bioenergetics and Mitochondrial Function | Cellular bioenergetics and mitochondrial function will be reported as oxygen consumption rate (pmol/min/10,000 cells). | Day 14 | 
| Monocyte Subtypes | Monocyte subtypes will be determined using flow cytometry (mean fluorescence intensity). | Day 1 | 
| Monocyte Subtypes | Monocyte subtypes will be determined using flow cytometry (mean fluorescence intensity). | Day 4 | 
| Monocyte Subtypes | Monocyte subtypes will be determined using flow cytometry (mean fluorescence intensity). | Day 11 | 
| Monocyte Subtypes | Monocyte subtypes will be determined using flow cytometry (mean fluorescence intensity). | Day 14 | 
| Monocyte Transcriptomics | Monocyte transcriptomics will be reported as gene expression (mRNA levels) | Day 1 | 
| Monocyte Transcriptomics | Monocyte transcriptomics will be reported as gene expression (mRNA levels) | Day 4 | 
| Monocyte Transcriptomics | Monocyte transcriptomics will be reported as gene expression (mRNA levels) | Day 11 | 
| Monocyte Transcriptomics | Monocyte transcriptomics will be reported as gene expression (mRNA levels) | Day 14 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Kidney stones, Dietary oxalate