With this study, we aim to gain insight in the influence of dietary oxalate on urinary oxalate levels by quantification of the intestinal oxalate absorption in patients with recurrent idiopathic calcium oxalate stones, primary hyperoxaluria, and…
ID
Source
Brief title
Condition
- Metabolic and nutritional disorders congenital
- Malabsorption conditions
- Urolithiases
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
1. To quantify dietary oxalate absorption from the gastrointestinal tract in
patients with idiopathic CaOx kidney stones, primary hyperoxaluria, and
secondary hyperoxaluria compared to healthy volunteers, by administering
labelled oxalate.
2. To identify differences in the intestinal microbiome between these patient
groups, by looking at the diversity and abundance of (oxalate degrading)
bacteria.
Secondary outcome
1. To identify differences in the intestinal metabolome by measuring volatile
and non-volatile organic compounds in the faeces and measuring labelled CO2 in
exhaled air.
Background summary
Urinary oxalate excretion is an important risk factor for calcium oxalate
kidney stones. If urinary oxalate levels exceed normal levels, this is referred
to as hyperoxaluria. Hyperoxaluria is a devastating disease, and patients with
hyperoxaluria may suffer from frequent stone events, nephrocalcinosis, and
eventually kidney impairment. In normal conditions, oxalate can be derived from
different sources, either by endogenous production in the liver, or by
intestinal oxalate absorption from food. The treatment of patients with
hyperoxaluria can be difficult. In an early stage of the disease this is
similar to the treatment of other calcium oxalate stone formers, and patients
are often advised to take medication, drink enough fluids, and follow a
restrictive diet to avoid high-oxalate foods. However, little is known about
the impact of an oxalate low diet on urinary oxalate levels in both these
patients. Some studies have been performed, mostly in patients with calcium
oxalate stones, showing that patients with idiopathic calcium oxalate
nephrolithiasis have increased absorption of oxalate from diet and have a less
diverse microbiome, with less oxalate degrading bacteria. However, these
studies were limited by taking only one of these two parameters into account.
Study objective
With this study, we aim to gain insight in the influence of dietary oxalate on
urinary oxalate levels by quantification of the intestinal oxalate absorption
in patients with recurrent idiopathic calcium oxalate stones, primary
hyperoxaluria, and enteric hyperoxaluria by using a revised stable isotope
method which will be correlated with the microbiome diversity and abundance of
oxalate degrading bacteria and network. Hereby, we will be able to provide more
insight in the impact of an oxalate-low diet, the gastrointestinal oxalate
metabolism, the role of the microbiome, and potential new targets for
therapeutics.
Study design
Experimental design.
Study burden and risks
Stable isotopes have been safely used in many studies in children and adults,
therefore no significant risks are associated with participation. The burden of
participation in the study consists of feces and urine sample collection, a
dietary restriction, a visit to the clinic, and assessment of relevant clinical
variables by questioning. The study burden is minimal since most patients are
familiar with similar dietary restrictions and 24-hours urine collections.
Meibergdreef 9
Amsterdam 1105 AZ
NL
Meibergdreef 9
Amsterdam 1105 AZ
NL
Listed location countries
Age
Inclusion criteria
For this study, we identify four different groups of participants:
Group 1: patients with primary hyperoxaluria.
Group 2: patients with secondary or unspecified hyperoxaluria
Group 3: patients with idiopathic calcium oxalate kidney stones disease.
Group 4: control group of healthy volunteers.
Inclusion criteria primary hyperoxaluria (group 1):
- Age 16 - 60 years
- Diagnosed with primary hyperoxaluria (type 1, 2 or 3), confirmed by genetic
testing.
Inclusion criteria secondary or unspecified hyperoxaluria (group 2):
- Age 16 - 60 years
- Diagnosed with secondary hyperoxaluria, confirmed by: hyperoxaluria (defined
as > 0.5 mmol/1.73m2/day oxalate in 24-hours urine) and confirmed diagnosis of
a disease as underlying secondary enteral cause of hyperoxaluria.
- Diagnosed with unspecified hyperoxaluria.
Inclusion criteria CaOx stone formers (group 3):
- Age 16 - 60 years
- Recurrent calcium oxalate stones
Inclusion criteria healthy volunteers (group 4):
- Age 16 - 60 years
- Good health, no background of nephrolithiasis, kidney or gastrointestinal
disease.
Exclusion criteria
- eGFR <30 ml/min/1.73m2
- Use of drugs affecting the gastrointestinal microbiome
- Gastro-intestinal or systemic diseases known to affect microbiome (causes of
secondary hyperoxaluria excluded)
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL80333.018.22 |