Characterization of the Metabolic Fate of an Oral Arginine Form

Study Overview
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Brief Summary
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The purpose of this study is to compare the metabolic fate of two oral forms of L-Arginine in healthy subjects featuring metabolic syndrome related risk factors

Detailed Description
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The study is a randomized crossover study including 16 healthy subjects with risk factors for metabolic syndrome and 16 healthy control subjects. According a double crossover design, each subject received two oral forms of L-arginine (A and B) in random order, and participated in a exploration day on the first day of arginine administration and after one week of supplementation with this arginine form. The two weeks of arginine supplementation were separated by a washout period of 2 weeks at least. Each exploration extended over 24 hours after administration of the first arginine dose. Blood tests were performed at 0, 0.5, 1, 2, 4, 6, 8, 12, 16, 24 h after administration of the first dose. During explorations after the supplementation period, we also collected urine (0, 2, 4, 8, 12, 24 h after the first dose).

Official Title
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Characterization of the Metabolic Fate of an Oral L-arginine Form in Healthy Subjects Featuring Risk Factors Related to the Metabolic Syndrome.

Conditions
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Overweight, Hypertriglyceridemic Waist

Intervention / Treatment
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* Dietary Supplement: A form Arginine
* Dietary Supplement: B form Arginine


Participation Criteria
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Eligibility Criteria
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Healthy subjects with 'Hypertriglyceridemic waist' : Inclusion Criteria: Age between 18 to 60 years old Overweight (BMI between 25 and 30 kg/m²) 'Hypertriglyceridemic waist' (waist circumference > 94cm for men or > 88cm for women and fasting triglyceride levels > 150 mg/dL) Exclusion Criteria: Obesity (BMI> 30 kg / m²) Cardiac or vascular diseases Diabetes Thyroid disease Systolic blood pressure > 150 mmHg or diastolic blood pressure > 90 mmHg Tobacco consumption > 6 cigarettes per week Alcohol consumption> 3 drinks per day Any medication (except contraceptive treatment) or dietary supplement intake that could not be arrested more than a week before the first visit for the duration of the study. Persons under guardianship Pregnancy (positive beta-hCG blood test) Positive serology HBsAg AcHbc, HCV and HIV Hemoglobin < 14 g/dl (for men) or <12 g / dl (for women) Participation in a clinical trial within 6 months preceding the study Healthy control subjects : Inclusion Criteria: Age between 18 to 60 years old Normal weight (BMI between 18.5 and 25 kg/m²) Waist circumference < 94cm for men or < 88cm for women and fasting triglyceride levels < 150 mg/dL Exclusion Criteria : Cardiac or vascular diseases Diabetes Thyroid disease Systolic blood pressure > 150 mmHg or diastolic blood pressure > 90 mmHg Tobacco consumption > 6 cigarettes per week Alcohol consumption> 3 drinks per day Any medication (except contraceptive treatment) or dietary supplement intake that could not be arrested more than a week before the first visit for the duration of the study. Persons under guardianship Pregnancy (positive beta-hCG blood test) Positive serology HBsAg AcHbc, HCV and HIV Hemoglobin < 14 g/dl (for men) or <12 g / dl (for women) Participation in a clinical trial within 6 months preceding the study

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Healthy subjects with 'hypertriglyceridemic waist'<br>Subjects with overweight, elevated waist circumference and elevated fasting triglyceridemia. Intervention : A form arginine and B form arginine | Dietary Supplement: A form Arginine<br>* 3 capsules containing 0.5g of A form of L-arginine (1.5g) 3 times daily (4.5g per day) for 1 week<br>Dietary Supplement: B form Arginine<br>* 3 capsules containing 0.5g of B form of L-arginine (1.5g) 3 times daily (4.5g per day) for 1 week<br>|
| Experimental: Healthy subjects<br>Control subjects, i.e. without overweight, elevated waist circumference and elevated fasting triglyceridemia. Intervention : A form arginine and B form arginine | Dietary Supplement: A form Arginine<br>* 3 capsules containing 0.5g of A form of L-arginine (1.5g) 3 times daily (4.5g per day) for 1 week<br>Dietary Supplement: B form Arginine<br>* 3 capsules containing 0.5g of B form of L-arginine (1.5g) 3 times daily (4.5g per day) for 1 week<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Estimate of total conversion of a dose of oral arginine into NO | This assessment uses labelled arginine ([15N2-(guanido)]-arginine) for the first dose of arginine taken in the morning, and measurements of 15NO3 in urine for 24h. After administration of 15N-arginine, for each urine collection, we determined the nitrate excretion (from measurement of diuresis and nitrate concentration, by reactive chemiluminescence) and isotope 15N enrichment of nitrate ion (by microdiffusion technique and elementary analyzer connected to an isotope mass spectrometerEA-IRMS), to establish, by the principle of isotopic dilution, the total quantities of nitrate specifically from the ingested arginine. The sum of this excretion relative to the ingested dose determined the relative conversion of ingested arginine into NO. | Repeated measurement for 24h before (day 0) and after supplementation (day 8) for each treatment | 
| Estimate of kinetic profiles of plasma arginine concentrations over 24 hours | Plasma AA concentrations were determined using an ultra-performance liquid chromatography-mass spectrometry system as previously described (Haque and al., 2012). | Repeated measurement for 24h before (day 0) and after supplementation (day 8) for each treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quantitative analysis of plasma markers of endothelial function | Fasting plasma concentrations of vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule (ICAM-1), E-Selectin, P-Selectin, Plasminogen activator inhibitor-1 (PAI-1), will be determined using two custom mixed assay kits with antibody-coated beads using the Luminex xMAP technology platform for multiplexing of immunochemical bioassays. In addition, we also have plasma concentrations of nitrite, a marker of of NO production (by reactive chemiluminescence) and other associated markers (3-nitrotyrosine, nitrosothiols, cGMP, in particular ANP, by immunochemistry). | Before supplementation (day 0) and after supplementation (day 8) for each treatment | 
| Estimate of kinetics use of arginine for NO and urea synthesis | After administration of 15N-arginine, we measured 15N isotopic enrichment of arginine and citrulline (by mass spectrometry coupled with gas chromatography), of plasma and urinary urea (by separation, by ion exchange, and EA-IRMS) as well as the plasma and urine concentrations in urea. These data and those of arginine and citrulline concentrations provided, by the principle of isotopic dilution, the plasma appearance of ingested arginine and the plasma appearance and urinary excretion of products of its metabolism in NO synthase and arginase ways. These data were then subjected to a compartmental modeling work to establish the metabolic flow in these ways. | Repeated measurement for 24h after supplementation (day 8) for each treament | 
| Other quantitative analysis | Fasting Asymmetric Dimethyl-L-Arginine (ADMA) concentrations were measured by an enzyme-linked immunosorbent assay. The fasting lipid profile (triglycerides, total cholesterol, HDL-cholesterol, LDL-cholesterol) was measured and were assayed using classical clinical biochemical analyzers. The fasting insulin and glucose were assayed using classical clinical biochemical analyzers. Fasting metabolomic analysis | Before supplementation (day 0) and after supplementation (day 8) for each treatment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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arginine, supplementation, metabolic syndrome, nitric oxide