Influence of Obesity on Endogenous Oxalate Synthesis
| Status: | Recruiting |
|---|---|
| Conditions: | Nephrology, Nephrology |
| Therapuetic Areas: | Nephrology / Urology |
| Healthy: | No |
| Age Range: | 25 - 60 |
| Updated: | 3/3/2019 |
| Start Date: | March 2019 |
| End Date: | March 2023 |
| Contact: | Dean Assimos, MD |
| Email: | dassimos@uab.edu |
| Phone: | 205-996-8765 |
There is increasing evidence that obesity is associated with increased urinary oxalate
excretion, an important risk factor for calcium oxalate stone formation. By the
administration of a controlled low oxalate diet the investigators will estimate endogenous
oxalate synthesis in both non-obese and obese non-kidney-stone forming adults. This study
seeks to thusly increase the understanding of the relationships between obesity and
endogenous oxalate synthesis to serve as a platform to develop novel therapies for stone
prevention.
excretion, an important risk factor for calcium oxalate stone formation. By the
administration of a controlled low oxalate diet the investigators will estimate endogenous
oxalate synthesis in both non-obese and obese non-kidney-stone forming adults. This study
seeks to thusly increase the understanding of the relationships between obesity and
endogenous oxalate synthesis to serve as a platform to develop novel therapies for stone
prevention.
Calcium oxalate stone disease results in billions of dollars in healthcare costs per year,
creates large economic losses due to decreased work productivity, and produces significant
pain and suffering in affected individuals impacting quality of life. Almost 9% of the
population in the United States may now experience a stone event at least once in their
lifetime and that figure is increasing. Although stone removing treatments have advanced in
the last few decades with a variety of minimally invasive procedures such as shock wave
lithotripsy, ureteroscopy and percutaneous nephrolithotomy, our knowledge of how stones form
and how to prevent them has not kept pace. Approximately 70-80% of the stones formed contain
oxalate. Oxalate is an end product of metabolism and an ubiquitous element of human diets.
Small increases in urinary oxalate can increase calcium oxalate crystal formation and thus
stone disease. Urinary oxalate levels are affected by both dietary and endogenous components,
complicating the discrimination between the two sources. Multiple epidemiological and
clinical studies have demonstrated a link between body mass index (BMI) and kidney stone
disease and also an increased urinary oxalate excretion.
The interpretation of studies suggesting a link between obesity and the amount of urinary
oxalate excreted is confounded by the failure in most studies to use diets controlled in
calcium and oxalate. Adult humans without a history of kidney stones will be placed on
controlled low oxalate diets to estimate the contribution of endogenous oxalate synthesis to
the urinary oxalate pool. In addition, oral doses of 13C2-glycolate and 13C6- vitamin C will
be used to determine their conversions to 13C2-oxalate and provide an index of endogenous
oxalate production. Body morphometric indices, markers of oxidative stress, and insulin
resistance will be assessed in these subjects.They will also be evaluated with DXA and MRI to
define body fat content and distribution.
creates large economic losses due to decreased work productivity, and produces significant
pain and suffering in affected individuals impacting quality of life. Almost 9% of the
population in the United States may now experience a stone event at least once in their
lifetime and that figure is increasing. Although stone removing treatments have advanced in
the last few decades with a variety of minimally invasive procedures such as shock wave
lithotripsy, ureteroscopy and percutaneous nephrolithotomy, our knowledge of how stones form
and how to prevent them has not kept pace. Approximately 70-80% of the stones formed contain
oxalate. Oxalate is an end product of metabolism and an ubiquitous element of human diets.
Small increases in urinary oxalate can increase calcium oxalate crystal formation and thus
stone disease. Urinary oxalate levels are affected by both dietary and endogenous components,
complicating the discrimination between the two sources. Multiple epidemiological and
clinical studies have demonstrated a link between body mass index (BMI) and kidney stone
disease and also an increased urinary oxalate excretion.
The interpretation of studies suggesting a link between obesity and the amount of urinary
oxalate excreted is confounded by the failure in most studies to use diets controlled in
calcium and oxalate. Adult humans without a history of kidney stones will be placed on
controlled low oxalate diets to estimate the contribution of endogenous oxalate synthesis to
the urinary oxalate pool. In addition, oral doses of 13C2-glycolate and 13C6- vitamin C will
be used to determine their conversions to 13C2-oxalate and provide an index of endogenous
oxalate production. Body morphometric indices, markers of oxidative stress, and insulin
resistance will be assessed in these subjects.They will also be evaluated with DXA and MRI to
define body fat content and distribution.
Inclusion Criteria:
- Age 25-60 years
- Body Mass Index (BMI) <40
Exclusion Criteria:
- history of kidney stones
- history of diabetes, hepatic disease, renal disease including Chronic Kidney Disease
(CKD), bowel disease or other endocrine disorders
- pregnant or lactating women, or those with the intention to become pregnant in the
near future
- abnormal liver enzymes
- hemoglobin A1C > 6.5
We found this trial at
1
site
1720 2nd Ave S
Birmingham, Alabama 35233
Birmingham, Alabama 35233
(205) 934-4011
Phone: 205-934-3671
University of Alabama at Birmingham The University of Alabama at Birmingham (UAB) traces its roots...
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