Clinical trial NCT02561858: Toxicity of Perirenal Fat in Overweight or Obese Subjects: A Pathophysiological Link Between Uric Acid Stones and Renal Ammonium Formation
Official title: Toxicity of Perirenal Fat in Overweight or Obese Subjects: A Pathophysiological Link Between Uric Acid Stones and Renal Ammonium Formation
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Uric Acid Stones
Keywords: Renal Ammonium ;uric acid
Lead sponsor: Centre Hospitalier Universitaire de Nice
Sponsor class: OTHER
First posted: 2015-09-28
Enrollment: 20
Sex: MALE
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NA
Intervention model: SINGLE_GROUP
Primary purpose: OTHER

Brief summary: Patients who are overweight or obese, diabetic or not, share with those who are suffering from uric stones the same way to remove abnormal acidity of the body in urine, ie a kidney ammoniogenesis default. This results in an overly acidic urine pH which is directly pathogenic in people predisposed to develop uric stones because the precipitation of urate soluble uric acid is accelerated in acid medium.

Excess visceral fat, particularly perirenal, this defect may promote formation of renal ammonium. Indeed, the perirenal fat is adjacent to the renal cortex and shares with it a common arterial supply via the plexus Turner. Adipokines and fatty acids of the perirenal fat are predisposed to gain the renal cortex, seat of the ammoniogenesis. In humans the pathogenic role of the perirenal fat is demonstrated in chronic kidney disease and essential hypertension. However, the amount of fat and perirenal that of intra-abdominal fat are positively correlated.

Investigators hypothesis is that the perirenal fat also exert a pathogenic role in uric because of anatomical links between kidney stones and greasy environment and because excess fatty acids reaching the renal cortex decreases ammoniogenesis in an animal model metabolic syndrome.

For the test, the investigators will compare the amount of fat and perirenal renal ability to form ammonium in patients with uric or calcium lithiasis taking into account the amount of intra-abdominal fat.


Eligibility criteria: Inclusion Criteria:

* Urolithiasis Uric defined by more than 90% of uric acid anhydrous and / or dihydrate or calcium lithiasis defined by more than 90% mono calcium oxalate and / or dihydrate, and / or carbapatite and / or brushite;
* Overweight and obesity defined by 25 \<BMI \<35 kg / m2

Exclusion Criteria:

* staghorn lithiasis, stones struvite or cystine;
* Primary hyperparathyroidism;
* Hyperthyroidism;
* Any form of calcium or uric lithiasis secondary;
* Abnormal kidney structure (cysts, cortical thinning, kidney tumor);

Primary outcomes:
measure: the perirenal fat thickness (left)
timeFrame: baseline
Secondary outcomes:
measure: the perirenal fat thickness (right)
timeFrame: baseline
measure: NH4 + / NAE
timeFrame: at day 7 of a standard diet
measure: net acid urinary flow
timeFrame: at day 7 of a standard diet and when urine pH became <5.5
Other outcomes:
Locations:
city: Nice
country: France
facility: CHU de Nice
Study officials:
References: