Gut Kidney Axis in Enteric Hyperoxaluria

Study Overview
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Brief Summary
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40 subjects with a confirmed diagnosis of IBD or >6 months post-RYGB with a diagnosed USD event or kidney stone on imaging within the past three years and 40 healthy controls will be administered a high oxalate diet on Days 0-3 and Days 21-24 with a washout period on Days 4-7 and will be administered 250mg sodium oxalate on Days 8-20, via prepared spinach, from Weil Cornell Medicine's Clinical and Translational Science Center. Subjects will partake in four stool collections, four 24-h urine collections, two blood collections, and four sets of colonic permeability testing.

Official Title
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Gut Kidney Axis in Enteric Hyperoxaluria: A Clinical Prospective Study of the Effects of the Microbiome on Urinary Oxalate in Participants With Enteric Hyperoxaluria Fed a Moderate Oxalate Diet

Conditions
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Enteric Hyperoxaluria

Intervention / Treatment
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* Other: Moderately High Oxalate (MOx) Diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: In order to be eligible to participate in this study, an individual must meet all of the following criteria: Subjects > 18 years and < 80 years of age a confirmed diagnosis of IBD or > 6 months post- RYGB, with a diagnosis USD event (renal colic with spontaneous stone passage, emergency room visits, or urological interventions) or have kidney stone on imaging (CT, MRI, or US) in the previous three years. We will include all racial and ethnic groups, and both men and women. In order to be eligible in this study as a healthy control, an individual must meet all of the following criteria: Subjects > 18 years and < 80 years of age Healthy controls with no chronic diseases, not on any chronic medications, no history of GI pathology, or urinary stone disease (USD). We will include all racial and ethnic groups, and both men and women. Exclusion Criteria: An individual who meets any of the following criteria will be excluded from participation in this study: pregnant or nursing women and people with any medical, psychiatric, debilitating disease/disorder or social condition that, in the judgment of the investigator, would interfere with or serve as a contraindication to adherence to the study protocol, ability to give ICF or complete the protocol. subjects with total and partial colectomy. subjects who received oral, intramuscular, or intravenous antibiotics within three months before screening. Patients with perianal disease usually receive recurrent antibiotics and, therefore, will be excluded from the study. patients with an ongoing symptomatic IBD flare or a flare within the previous three months patients with estimated glomerular filtration rates (eGFR) < 60 ml/min/1.73 m2 calculated by the CKD-EPI equation measured anytime within the preceding year. An individual who meets any of the following criteria will be excluded from participation in this study as a healthy control: pregnant or nursing women and people with any medical, psychiatric, debilitating disease/disorder or social condition that, in the judgment of the investigator, would interfere with or serve as a contraindication to adherence to the study protocol, ability to give ICF or complete the protocol. subjects with total and partial colectomy. subjects who received oral, intramuscular, or intravenous antibiotics within three months before screening. Patients with perianal disease usually receive recurrent antibiotics and, therefore, will be excluded from the study. patients with an ongoing symptomatic IBD flare or a flare within the previous three months patients with estimated glomerular filtration rates (eGFR) < 60 ml/min/1.73 m2 calculated by the CKD-EPI equation measured anytime within the preceding year.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 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: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Healthy Controls<br> | Other: Moderately High Oxalate (MOx) Diet<br>* Diets will contain 16% protein, 30% fat, and 54% carbohydrate, and are controlled in the amounts of calcium (400mg), oxalate (250mg), ascorbic acid (50mg), fiber (30 grams) and, other nutrients. Each controlled diet will be consumed for four days. On days of controlled diets, subjects will be provided with 2 liters of bottled water per day to ensure adequate hydration. After the controlled diet period, there will be a three-day washout period, where participants will consume Ad-lib diets supplemented with a daily intake of oxalate in the form of cooked spinach to be taken with breakfast daily for a total of 2 weeks.<br>|
| Experimental: Enteric Hyperoxaluria<br> | Other: Moderately High Oxalate (MOx) Diet<br>* Diets will contain 16% protein, 30% fat, and 54% carbohydrate, and are controlled in the amounts of calcium (400mg), oxalate (250mg), ascorbic acid (50mg), fiber (30 grams) and, other nutrients. Each controlled diet will be consumed for four days. On days of controlled diets, subjects will be provided with 2 liters of bottled water per day to ensure adequate hydration. After the controlled diet period, there will be a three-day washout period, where participants will consume Ad-lib diets supplemented with a daily intake of oxalate in the form of cooked spinach to be taken with breakfast daily for a total of 2 weeks.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Urinary Oxalate Levels (UOx) | UOx will be quantified in 24-h samples | Day 2-3 | 
| Urinary Oxalate Levels (UOx) | UOx will be quantified in 24-h samples | Day 23-24 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total Fecal Oxalate Levels |  | Day 2-3 | 
| Total Fecal Oxalate Levels |  | Day 14 | 
| Total Fecal Oxalate Levels |  | Day 23-24 | 
| Urinary Calcium Levels |  | Day 2-3 | 
| Urinary Calcium Levels |  | Day 23-24 | 
| Sucralose Levels |  | Day 2-3 | 
| Sucralose Levels |  | Day 23-24 | 
| Calcium Oxalate (CaOx) Supersaturation Levels |  | Day 2-3 | 
| Calcium Oxalate (CaOx) Supersaturation Levels |  | Day 23-24 | 
| Plasma Oxalate Levels |  | Day 2-3 | 
| Plasma Oxalate Levels |  | Day 23-24 |