Menopause
Conditions
Keywords
Endothelial function, Blood pressure, Blood flow
Brief summary
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.
Detailed description
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).
Interventions
DIETARY_SUPPLEMENTL-Citrulline
4 weeks of L-Citrulline supplementation (6 grams/day)
DIETARY_SUPPLEMENTPlacebo
4 weeks of Placebo (crystalline cellulose)
Sponsors
Texas Tech University
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Intervention model description
Double (Participant, Investigator) Randomized, double-blind, placebo-controlled, parallel study design
Eligibility
Sex/Gender
FEMALE
Age
50 Years to 79 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Muscle oxygenation during dynamic exercise | 4 weeks | Muscle oxygenation will be measured using near infrared spectroscopy during dynamic exercises superimposed with the cold pressor test. |
| Changes in brachial and aortic blood pressure responses via automated sphygmomanometry during metaboreflex activation | 4 weeks | Brachial and aortic blood pressures (systolic and diastolic) will be assessed using an arm cuff during isometric handgrip exercise and postexercise muscle ischemia. |
| Changes in aortic hemodynamics using pulse wave analysis during metaboreflex activation | 4 weeks | 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. |
| Blood flow during dynamic exercise | 4 weeks | Blood flow will be measured using ultrasound in the superficial femoral and brachial artery during dynamic exercises superimposed with the cold pressor test. |
| Microvascular endothelial function | 4 weeks | Endothelial function will be assessed via reactive hyperemic index using the EndoPAT device. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Changes in brachial and aortic blood pressure responses via automated sphygmomanometry during dynamic plantarflexion exercise and handgrip combined with the cold pressor test | 4 weeks | Brachial and aortic blood pressures (systolic and diastolic) will be assessed using an arm cuff during dynamic plantarflexion exercise and handgrip combined with the cold pressor test. |
| Changes in aortic hemodynamics using pulse wave analysis during dynamic plantarflexion exercise and handgrip combined with the cold pressor test | 4 weeks | 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 dynamic plantarflexion exercise and handgrip combined with the cold pressor test. |
| Serum nitric oxide levels | 4 weeks | Serum levels of nitric oxide will be assessed. |
Countries
United States
Outcome results
None listed