Effects of L-citrulline Supplementation on Vascular Function in Metabolic Syndrome

Texas Tech University24 enrolled

Overview

The objective of this project is to provide evidence that L-Citrulline (CIT) supplementation can improve vascular function in the fasted and acute hyperglycemia conditions in middle-aged and older women with metabolic syndrome.

Using a double-blind, randomized, placebo-controlled, and parallel design, middle-aged and older women with metabolic syndrome will be randomized into receiving either CIT supplementation (10g/day) or placebo (Microcrystalline Cellulose) for 4 weeks. The first visit will be approximately 1hr and 30 minutes. The 2nd and 3rd visits will each be approximately 2hrs and 30 minutes, separated by 4 weeks in between each visit. During visits 2 and 3, vascular measurements will be assessed in the fasted state and 30, 60, and 90 minutes after acute glucose ingestion (75g).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Metabolic Syndrome Menopause

Interventions

L-Citrulline supplementationDIETARY_SUPPLEMENT

4 weeks of L-Citrulline supplementation (10 grams/day).

PlaceboDIETARY_SUPPLEMENT

4 weeks of microcrystalline Cellulose supplementation.

Eligibility

Sex: FEMALEMin age: 45 YearsMax age: 79 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: Must present at least 3 of the following 5 cardiometabolic risk factors * Waist circumference ≥88 cm * Fasting glucose between 100-125 mg/dL or HbA1c between 5.7-6.4%. * Blood pressure ≥130 mm Hg * Triglyceride ≥ 150 mg/dL * HDL \<50 mg/dL The following are also inclusion criteria's: * Women aged 45-79 years old * Body mass index ≤ 39.9 kg/m2 * Sedentary (defined as \< 120 min/week of exercise) * Abstain from any dietary supplements with vascular effects for one month prior to the beginning of the study and until participation in study has terminated. Exclusion Criteria: * \< 45 and \> 79 years of age * Use of medications and/or any supplements that may affect outcome variables (such as arginine-containing supplements, nitroglycerin, statin drugs, biguanides, insulin, beta blockers, statins, verapamil) * Systolic blood pressure ≥ 160 mmHg * BMI \> 40 kg/m2 * Recent changes in medication (3 months) * Current smoking any tobacco use * Cardiovascular disease, diabetes (Type 1 or 2), and other metabolic or chronic diseases * More than 7 alcoholic drinks/week of consumption

Locations (1)

TTU Kinesiology and Sport Management Building

Lubbock, Texas, United States

Outcomes

Primary Outcomes

Macrovascular Endothelial function in the fasted condition

Endothelial function will be measured via brachial artery flow mediated dilation (ultrasonography) during reactive hyperemia at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Microvascular endothelial function in the fasted condition

Endothelial function will be measured using forearm muscle oxygenation (near-infrared spectroscopy) will assessed during reactive hyperemia at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Microvascular digital endothelial function in the fasted condition

Endothelial function will be measured using peripheral (finger) arterial tonometry (EndoPAT device) during reactive hyperemia at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Macrovascular Endothelial function during acute hyperglycemia

Endothelial function will be measured via brachial artery flow mediated dilation (ultrasonography) during reactive hyperemia at 30, 60, and 90 minutes after oral glucose ingestion at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Microvascular forearm endothelial function during acute hyperglycemia

Endothelial function will be measured using forearm muscle oxygenation (near-infrared spectroscopy) during reactive hyperemia at 30, 60, and 90 minutes after oral glucose ingestion at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Central and peripheral arterial stiffness in the fasted condition

Arterial stiffness will be measured using central (carotid-femoral) and peripheral (femoral-ankle) PWV at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Data from ClinicalTrials.gov

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Secondary Outcomes

Serum glucose and insulin levels.

Serum glucose and insulin levels will be tested at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Serum arginine levels

Serum L-Arginine levels will be tested at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Serum arginase levels

Serum arginase levels will be tested at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Serum Nitric Oxide levels

Serum nitric oxide levels will be tested at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks

Serum Endothelin-1 levels

Serum endothelin-1 levels will be tested at baseline and after 4 weeks of supplementation.

Time frame: 4 weeks