Clinical Trial: Renal Uptake of Fatty Acids (FFA) in Patients With Idiopathic Uric Acid Nephrolithiasis (IUAN)

Study Status: Not yet recruiting
Recruit Status: Not yet recruiting
Study Type: Interventional

Official Title: Renal Uptake of Fatty Acids (FFA) in Patients With Idiopathic Uric Acid Nephrolithiasis (IUAN)

Brief Summary:

We will test the hypothesis that renal uptake of free (i.e. non-esterified) fatty acids (FFa) is increased in iuan. To accomplish this goal we will measure renal FFa uptake FFa uptake in vivo in patients with iuan and matched non-stone forming subjects via single-photon emission computed tomography (SPeCT)/CT imaging.

The definitive proof of our hypothesis rests on whether increased renal FFa uptake is demonstrable in humans with iuan.


Detailed Summary:

This is a cross-sectional study of patients with iuan and matched non-stone formers to test the hypothesis that renal FFa uptake is increased in iuan, using noninvasive 123i-labeled [MiCRo-SYMBoL]-methyl-p-iodo-phenyl-pentadecanoic acid(123i-BMiPP) SPeCT/CT imaging, an established FFa analog approved for human studies.

Participants will be placed on an instructed controlled metabolic diet (30% fat, 15% protein, 55% carbohydrate, 300 mg cholesterol per day, 400 mg calcium, 800mg phosphorus, 100 meq sodium, with low acid ash content, and 3000 cc distilled water) for 5 days to exclude dietary confounders (3 days as outpatient and the final 2 days as inpatient). on days 4 and 5, two fasting blood samples will be collected for the measurement of CMP, insulin, FFa and two 24-h urine samples will be collected under mineral oil to be analyzed for total volume, pH, Cr, na, K, Ca, Mg, Cl, P, uric acid, nH4+, titratable acidity (Ta), sulfate, HCo3- and citrate. The morning of day 6, patients will undergo dual 123i-BMiPP and 99mTc-MaG3 (99mTc mercaptoacetyltriglycine mertiatide) SPeCT/CT imaging after 12 hrs of fasting. 99mTc-MaG3 (8-10mCi) will be injected intravenously for the flow phase of a standard renal scan which includes dynamic imaging for 2 minutes. an additional 1 minute image will be acquired (the 2-3 minute image on a standard renal scan). acquisition will then stop. immediately afterward 123i-BMiPP (4-5mCi) will be injected intravenously for a 1hour uptake period. after the 1 hour uptake dual isotope (Tc-99m and i-123) SPeCT/CT images of the kidney will be acquired on a clinical Siemens Symbia dual head SPeCT/CT system. The 99mTc-MaG3 flow image data will be used to measure renal plasma flow,12 using the Ge Xeleris renal analysis software package already installed on our clinical SPeCT/CT system. The 123i-BMiPP, a gamma emitter with a half-life of 13.13 hours, is to mea
Sponsor: University of Texas Southwestern Medical Center

Current Primary Outcome: Increased FFA uptake as measured by 123I-BMIPP SPECT/CT corrected for renal effective plasma flow in the kidney cortex of IUAN patients vs. matched controls [ Time Frame: 6 days ]

Based on preliminary animal study, we anticipate a mean difference of approximately 26% between IUAN and control non-stone forming subjects, but with a higher CV of 20%. For 80% power (=0.05), will be able to detect at 1.5 standardized effect size (%change/CV) with n=10 per group. Comparisons between IUAN and non-stone former groups will be made with two-sample t-tests or Wilcoxon Rank Sum tests.


Original Primary Outcome: Same as current

Current Secondary Outcome:

Original Secondary Outcome:

Information By: University of Texas Southwestern Medical Center

Dates:
Date Received: November 23, 2016
Date Started: January 2017
Date Completion: December 2021
Last Updated: November 23, 2016
Last Verified: November 2016