Influence of Obesity on Oxalate Metabolism and Handling in Calcium Oxalate Stone Formers

The primary goals of this study are to determine the contribution of dietary oxalate absorption, renal oxalate handling, and endogenous oxalate synthesis to urinary oxalate excretion in normal Body Mass Index (BMI) and obese calcium oxalate kidney stone formers.

Study Overview

• Status: Active, not recruiting
• Conditions: Kidney Stone
• Intervention / Treatment: Other: Controlled Diet; Dietary supplement: Carbon-13 Oxalate and Sucralose Ingestion

• Study Type: Interventional
• Enrollment (Actual): 22
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Alabama
    • Birmingham, Alabama, United States, 35243-3353
      • University of Alabama at Birmingham
  • Texas
    • Dallas, Texas, United States, 75390
      • University of Texas Southwestern Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 19 years to 75 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Normal Body Mass Index (≥ 18.5 to < 25); Obese Body Mass Index (≥ 30 to ≤ 45)
• Able to provide informed consent
• Willingness to consume controlled diet
• Composition of most recent stone > 50% calcium oxalate, no uric acid component
• First time or recurrent calcium oxalate stone former
• 24-hour urine collections with creatinine values within 20% of appropriate ratio of creatinine (mg)/body weight (kg) for gender, and with creatinine values that are consistent between collections (within 20% of each other)
• Willingness to stop supplements [vitamins, Ca (citrate or carbonate) and other minerals, herbal supplements, nutritional aids, probiotics] for 14 days before start and during study
• Willingness to not undertake vigorous exercise during the controlled dietary study
• Normal fasting blood Comprehensive Metabolic Panel
• Hemoglobin A1c < 6.5%
• No food allergies or intolerance to any of the food in study menus
• Permitted/willing to discontinue medications for kidney stone prevention, including thiazides, allopurinol, and febuxostat and citrate preparations, for 14 days before start and during the studies. They will be instructed to restart these medications at the conclusion of the study

Exclusion Criteria:

• Diabetes
• Abnormal fasting comprehensive metabolic panel (CMP)
• Hemoglobin A1c (HbA1c) result ≥ 6.5%
• Gout
• Estimated Glomerular Filtration Rate (eGFR) <60 ml/min/1.73m^2
• Primary hyperoxaluria
• Cystic fibrosis
• Cystinuria
• Uric acid stone former
• Utilization of immunosuppressive medication
• Nephrotic syndrome
• Enteric hyperoxaluria
• Gastrointestinal disorder that could impact oxalate transport
• Sarcoidosis
• Uncontrolled hypertension
• Renal tubular acidosis
• Primary hyperparathyroidism
• Liver disease
• Neurogenic bladder
• Urinary diversion
• Chronic diarrhea
• Bariatric surgery
• Active malignancy or treatment for malignancy within 12 months prior to screening
• Pregnancy
• Breast feeding/nursing
• Females of child bearing age who are not able to use an effective method of birth control during the study
• Mental/medical condition that is likely to impede successful study completion
• Illness including flu / common cold / fever 14 days before study and during study
• Diarrhea or other abnormal gastrointestinal event (e.g. abnormal bowel movements) 14 days before study or during study
• Antibiotic use within last 6 months (based on recommendations of the NIH Human Microbiome Project, Protocol A)
• Inability or unwillingness to undergo MRI

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Controlled Dietary Study; Participants will consume the controlled diet for five days. After one day on the diet, subjects will provide three 24-hour urine collections. On the last dayof the diet, subjects will come in a fasted state to ingest a small amount of carbon-13 oxalate and sucralose, with hourly urine collections and blood samples being taken before and after the ingestion.

Other: Controlled Diet; Participant will consume a controlled low oxalate diet for five days; Dietary supplement: Carbon-13 Oxalate and Sucralose Ingestion; Subjects will ingest a small amount of carbon-13 oxalate and sucralose, dissolved in water.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Urinary Oxalate Excretion	Urinary oxalate excretion from urine samples will be measured as mg/day	Baseline through Day 5

Collaborators and Investigators

• Sponsor: University of Alabama at Birmingham
• Investigators: Principal Investigator: Dean Assimos, MD, University of Alabama at Birmingham

Study record dates

Study Major Dates

• Study Start (Actual): September 1, 2021
• Primary Completion (Estimated): December 1, 2024
• Study Completion (Estimated): December 1, 2025

Study Registration Dates

• First Submitted: April 1, 2020
• First Submitted That Met QC Criteria: April 1, 2020
• First Posted (Actual): April 3, 2020

Study Record Updates

• Last Update Posted (Estimated): February 22, 2024
• Last Update Submitted That Met QC Criteria: February 20, 2024
• Last Verified: February 1, 2024

More Information

Terms related to this study

• Keywords: kidney stone; oxalate
• Additional Relevant MeSH Terms: Kidney Diseases; Urologic Diseases; Pathological Conditions, Anatomical; Urolithiasis; Urinary Calculi; Calculi; Female Urogenital Diseases; Female Urogenital Diseases and Pregnancy Complications; Urogenital Diseases; Male Urogenital Diseases; Kidney Calculi; Nephrolithiasis
• Other Study ID Numbers: IRB-300004693

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No