Citrulline Supplementation On Vascular Responsiveness and Function in Postmenopausal Women

Texas Tech University26 enrolled

Overview

The objective of this project is to provide evidence that L-Citrulline (L-CIT) supplementation can improve vascular function at rest and in response to exercise in postmenopausal women.

L-CIT is a non-essential amino acid that is a precursor to L-arginine, the substrate used to produce an important vasodilatory molecule called nitric oxide. The purpose of this study is to identify the effects of 6 grams of L-CIT for 4 weeks on vascular function (endothelial function, blood flow, muscle oxygenation, and blood pressure) at rest and in response to different stressors (cold pressor test, isometric and dynamic exercise).

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Menopause

Interventions

L-CitrullineDIETARY_SUPPLEMENT

4 weeks of L-Citrulline supplementation (6 grams/day)

PlaceboDIETARY_SUPPLEMENT

4 weeks of Placebo (crystalline cellulose)

Eligibility

Sex: FEMALEMin age: 50 YearsMax age: 79 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * Postmenopausal (absence of menstruation \> 1 year) between the ages of 50 - 79 years. * Sedentary ( \< 120 minutes of exercise/week) * Resting systolic blood pressure \< 150 mmHg and diastolic blood pressure \< 90 mmHg * Not participating as a subject in another study for at least 2 months prior to the study and for the duration of the study * Willingness to abstain from food supplements 1 month prior to the start of the study and throughout the duration of the study Exclusion Criteria: * Body mass index ≥ 40 * Currently taking more than one vasoactive drug for blood pressure control * Cardiometabolic diseases or other chronic diseases * Taking hormone replacement therapy 3 months prior to the study * Current or prior use of tobacco products * More than a moderate intake of alcohol * Use of medications and/or supplements that may affect outcome variables * Musculoskeletal disorders that will prevent exercise performance

Locations (1)

Texas Tech University

Lubbock, Texas, United States

Outcomes

Primary Outcomes

Microvascular endothelial function

Endothelial function will be assessed via reactive hyperemic index using the EndoPAT device.

Time frame: 4 weeks

Changes in brachial and aortic blood pressure responses via automated sphygmomanometry during metaboreflex activation

Brachial and aortic blood pressures (systolic and diastolic) will be assessed using an arm cuff during isometric handgrip exercise and postexercise muscle ischemia.

Time frame: 4 weeks

Changes in aortic hemodynamics using pulse wave analysis during metaboreflex activation

The speed and reflection pressures, both representing aortic hemodynamic parameters, will be assessed using radial applanation tonometry and a validated transfer function (AtCor Medical) during isometric handgrip exercise and postexercise muscle ischemia.

Time frame: 4 weeks

Blood flow during dynamic exercise

Blood flow will be measured using ultrasound in the superficial femoral and brachial artery during dynamic exercises superimposed with the cold pressor test.

Time frame: 4 weeks

Muscle oxygenation during dynamic exercise

Muscle oxygenation will be measured using near infrared spectroscopy during dynamic exercises superimposed with the cold pressor test.

Time frame: 4 weeks

Secondary Outcomes

Serum nitric oxide levels

Serum levels of nitric oxide will be assessed.

Time frame: 4 weeks

Changes in brachial and aortic blood pressure responses via automated sphygmomanometry during dynamic plantarflexion exercise and handgrip combined with the cold pressor test

Data from ClinicalTrials.gov

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