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| ID | Type | Description | Link |
|---|---|---|---|
| K01DK114332 | U.S. NIH Grant/Contract | View source | |
| UAB | Other Identifier | UAB |
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| Name | Class |
|---|---|
| National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) | NIH |
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This study will determine the contribution of glycolate metabolism to urinary oxalate excretion in healthy subjects, using carbon 13 isotope glycolate tracer technique and a low-oxalate controlled diet.
It is known that glycolate, an intermediary molecule in normal metabolism, can be converted into oxalate. The origin of urinary oxalate is of interest as calcium oxalate is a main component of kidney stones. In the rare disease primary hyperoxaluria, excessive production of oxalate by the body results in frequent kidney stones and can cause loss of kidney function. Primary hyperoxaluria is caused by deficiencies in one of several enzymes involved in the glycolate pathway.
This study will seek to determine how much oxalate is formed from glycolate in normal subjects. After consuming a controlled diet, subjects will either ingest or have an intravenous infusion of carbon 13 glycolate, a stable isotope of glycolate that can be tracked and will also label downstream metabolic products. Blood and urine samples will be assessed for their amounts of labeled glycolate and labeled oxalate to provide an accurate measure of how much oxalate is made from normal glycolate breakdown in healthy human subjects.
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| Label | Type | Description | Intervention Names |
|---|---|---|---|
| Constant Infusion of 13C2-Glycolate | Experimental | Subjects will consume a controlled diet for 5 days total. On Days 3 and 4, subjects will collect 24 hour urines. On Day 5, they will come to the Clinical Research Unit (CRU) in the fasted state for a visit lasting from 7:00 am to 5:30 pm. An intravenous (IV) catheter will be placed in a vein on the back of the hand at 7:30 am for the carbon 13 glycolate infusion which will occur at a constant rate for 10 hours, following a priming dose. From 7:30 am to 5:30 pm, urine collections will occur hourly, and from 8:30 am to 5:30 pm, IV blood collections will occur every half hour. Subjects will receive a meal at 5:30 pm, thus concluding the CRU visit. At home, subjects will collect timed urine until the next morning to be returned to the CRU. |
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| Single Intravenous Dose of 13C2-Glycolate | Experimental | Subjects will consume a controlled diet for 5 days total. On Days 3 and 4, subjects will collect 24 hour urines. On Day 5, they will come to the Clinical Research Unit (CRU) in the fasted state for a visit lasting from 7:00 am to 2:30 pm. An intravenous (IV) catheter will be placed in a vein on the back of the hand at 8:30 am for a single dose of carbon-13 glycolate to be administered. From 7:30 am to 2:30 pm, urine collections will occur hourly. At 8:30 am, IV blood samples will be taken every fifteen minutes until 9:30 am, every half hour from 9:30 am to 10:30 am, and then finally hourly from 10:30 am to 2:30 pm . Subjects will receive a meal at 2:30 pm, thus concluding the CRU visit. At home, subjects will collect timed urine until the next morning to be returned to the CRU. |
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| Single Oral Dose of 13C2-Glycolate | Experimental |
| Name | Type | Description | Arm Group Labels | Other Names |
|---|---|---|---|---|
| Low oxalate controlled Diet | Dietary Supplement | Participants will consume a diet that is controlled in its contents of protein, carbohydrates, fat, calcium, oxalate, vitamin C and sodium. Participants will be asked not to take any dietary supplements, exercise strenuously, or consume food or drink that is not provided to them. |
| Measure | Description | Time Frame |
|---|---|---|
| Urinary oxalate measured by ion chromatography coupled with mass spectrometry | Measurement of carbon 13 labeled and unlabeled urinary oxalate following carbon 13 glycolate administration, after equilibration under a low-oxalate diet. | day 5 of dietary control |
| Plasma glycolate measured by ion chromatography coupled with mass spectrometry | Measurement of carbon 13 labeled and unlabeled plasma glycolate following carbon 13 glycolate administration, after equilibration under a low-oxalate diet. | day 5 of dietary control |
| Measure | Description | Time Frame |
|---|---|---|
| Urinary creatinine | Baseline assessment of 24hr urinary creatinine under controlled low-oxalate diet. | day 5 of dietary control |
| Urinary glycolate measured by ion chromatography coupled with mass spectrometry |
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Inclusion Criteria:
Exclusion Criteria:
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| Name | Affiliation | Role |
|---|---|---|
| Sonia Fargue, M.D., Ph.D. | University of Alabama at Birmingham | Principal Investigator |
| Facility | Status | City | State | ZIP | Country | Contacts |
|---|---|---|---|---|---|---|
| University of Alabama at Birmingham | Birmingham | Alabama | 35233 | United States |
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| ID | Term |
|---|---|
| D007669 | Kidney Calculi |
| D052878 | Urolithiasis |
| ID | Term |
|---|---|
| D053040 | Nephrolithiasis |
| D007674 | Kidney Diseases |
| D014570 | Urologic Diseases |
| D052776 | Female Urogenital Diseases |
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Subject will undergo the gold-standard technique of steady-state intravenous infusion of 13-glycolate administration. Selected subjects will also undergo other modified modalities of 13-glycolate administration.
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Subjects will consume a controlled diet for 5 days total. On Days 3 and 4, subjects will collect 24 hour urines. On Day 5, they will come to the Clinical Research Unit (CRU) in the fasted state for a visit lasting from 7:00 am to 2:30 pm. At 8:30 am, subjects will ingest the carbon-13 glycolate, dissolved in to 50 ml (about 1/4 cup) of water. From 7:30 am to 2:30 pm, urine collections will occur hourly. At 8:30 am, intravenous (IV) blood samples will be taken every fifteen minutes until 9:30 am, every half hour from 9:30 am to 10:30 am, and then finally hourly from 10:30 am to 2:30 pm . Subjects will receive a meal at 2:30 pm, thus concluding the CRU visit. At home, subjects will collect timed urine until the next morning to be returned to the CRU.
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| Primed, continuous intravenous infusion of 13C2-Glycolate | Other | Participants will receive a continuous intravenous administration of carbon-13 glycolate, a naturally occurring form of glycolate, over the course of several hours until steady-state is achieved, using an IV catheter. |
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| Bolus intravenous infusion of 13C2-Glycolate | Other | Participants will receive a bolus intravenous administration of carbon-13 glycolate, a naturally occurring form of glycolate, using an IV catheter. |
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| Oral bolus administration of 13C2-Glycolate | Other | Participants will orally ingest a single dose of carbon-13 glycolate, a naturally occurring form of glycolate. |
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Measurement of carbon 13 labeled and unlabeled urinary glycolate following carbon 13 glycolate administration, after equilibration under a low-oxalate diet.
| day 5 of dietary control |
| D005261 |
| Female Urogenital Diseases and Pregnancy Complications |
| D000091642 | Urogenital Diseases |
| D014545 | Urinary Calculi |
| D052801 | Male Urogenital Diseases |
| D002137 | Calculi |
| D020763 | Pathological Conditions, Anatomical |
| D013568 | Pathological Conditions, Signs and Symptoms |