- ICH GCP
- US Clinical Trials Registry
- Clinical Trial NCT01462591
L-citrulline Supplementation & Cold Exposure
The Effects L-citrulline Supplementation on Arterial Stiffness, Wave Reflection, and Cardiac Autonomic Responses to Cold Exposure With Isometric Exercise
Study Overview
Detailed Description
The specific aims of the study are:
AIM 1: To determine the acute effects of cold exposure and isometric exercise, on cardiovascular hemodynamics and autonomic regulation. The working hypothesis is that the combination of cold exposure with isometric hand grip (IHG) exercise would evoke a greater acute increase in arterial stiffness, wave reflection, arterial BP and sympathetic activity than cold exposure or IHG alone. In order to test this hypothesis, the investigators will use an environmental chamber at a temperature of 4oC to perform non-invasive measurements of arterial stiffness (carotid-femoral, femoral-ankle, and brachial-ankle pulse wave velocity [PWV]), pulse wave analysis (aortic BP and augmentation index [AIx]) using applanation tonometry of the radial artery. In addition, the investigators will use continuous beat-by-beat digital BP, power spectral analysis of heart rate variability and blood pressure variability, and spontaneous BRS to evaluate autonomic function during cold exposure.
AIM 2: To examine the effects of L-citrulline supplementation on cardiovascular hemodynamics, autonomic regulation and endothelial function. The investigators will test the working hypothesis that L-citrulline supplementation for 14 days will attenuate the cardiovascular responses to physiological stress. The investigators will perform the same procedures previously specified in AIM I.
AIM 3: To determine the acute and chronic L-citrulline supplementation on endothelial function by measuring flow-mediated vasodilation, vasoactive substances, and Endothelial Progenitor Cells (EPCs). This aim will examine the working hypothesis L-citrulline will result in greater circulating levels of vasodilatory substances including nitric oxide, prostacyclin, and EPCs whereas vasoconstrictor substances endothelin-I (ET-1) will decrease. This aim will be tested by measuring serum levels of these substances before and immediately after the session at baseline and 7 days after the intervention.
Description of the study Forty individuals (20 men and 20 women) 18-35 years of age with normal resting BP (< 140/90 mmHg) will be enrolled in this study. Subjects should not be smokers, L-citrulline users or regular exercisers (defined as more than 120 min per week) in the last 6 months. The exclusion criteria will be any contraindication to exercise and medical conditions. Subjects with diverse ethnic backgrounds will be recruited from the Tallahassee metropolitan area by advertisement and direct communication.
Study design:
After completion of initial screening, cardiovascular function of eligible subjects will be evaluated at a room temperature of 4oor 23oC in random order. After baseline measurements, subjects will be randomly assigned to Placebo (Malt dextrin) or L-citrulline group for 14 days. Cardiovascular function will be evaluated at the end of the study.
Study Type
Enrollment (Actual)
Phase
- Phase 2
- Phase 1
Contacts and Locations
Study Locations
-
-
Florida
-
Tallahassee, Florida, United States, 32306
- FSU College of Human Sciences
-
-
Participation Criteria
Eligibility Criteria
Ages Eligible for Study
Accepts Healthy Volunteers
Genders Eligible for Study
Description
Inclusion Criteria:
- Men
- Blood pressure lower than 140/90mmHg
- Age 18 to 35 years
- BMI 20-39 kg/m2
Exclusion Criteria:
- Blood Pressure >160/100 mmHg
- Asthma
- Glaucoma
- Herpes simplex
- Uncontrolled diabetes
- Neurological disease
- Cardiovascular disease
- Inflammatory disease
- Kidney disease
- Hormone replacement therapy (HRT)
- Amino acid/vitamin supplementation\
- Corticosteroids or non-steroidal anti-inflammatory drugs
- Any drug known to affect BP or heart rate
- Glycemic control drugs
- Lipids reducing drugs
- Participants should not consume > 12 alcoholic drink/week
- Smokers
- Regular Exercisers (>1.5 hour/week).
Study Plan
How is the study designed?
Design Details
- Primary Purpose: Prevention
- Allocation: Randomized
- Interventional Model: Crossover Assignment
- Masking: Double
Arms and Interventions
Participant Group / Arm |
Intervention / Treatment |
---|---|
Experimental: L-citrulline
L-citrulline (100mg/kg of body weight per day for 2 weeks)
|
2 weeks of L-citrulline supplementation (100mg/kg of body weight).
|
Placebo Comparator: Maltodextrin
6g/day of placebo (maltodextrin)
|
2 weeks of L-citrulline supplementation (100mg/kg of body weight).
|
What is the study measuring?
Primary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Blood Pressure
Time Frame: 6 weeks
|
By measuring brachial and central (aortic and carotid) BP at rest and during physiological stress (cold exposure and handgrip test)
|
6 weeks
|
Secondary Outcome Measures
Outcome Measure |
Measure Description |
Time Frame |
---|---|---|
Autonomic control of heart rate
Time Frame: 6 weeks
|
By measuring heart rate variability at rest and during physiological stress.
|
6 weeks
|
Collaborators and Investigators
Sponsor
Investigators
- Principal Investigator: Marcos A Sanchez-Gonzalez, M.D., The Florida State University
Study record dates
Study Major Dates
Study Start
Primary Completion (Actual)
Study Completion (Actual)
Study Registration Dates
First Submitted
First Submitted That Met QC Criteria
First Posted (Estimate)
Study Record Updates
Last Update Posted (Estimate)
Last Update Submitted That Met QC Criteria
Last Verified
More Information
Terms related to this study
Additional Relevant MeSH Terms
Other Study ID Numbers
- HSC2011.6686
Drug and device information, study documents
Studies a U.S. FDA-regulated drug product
Studies a U.S. FDA-regulated device product
product manufactured in and exported from the U.S.
This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.
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