An Evaluation of Folic Acid to Improve Endothelial Sensitivity to Shear Stress in Seniors

Study Overview
=================
Brief Summary
-----------------
The purpose of this study is to evaluate if folic acid improves endothelial sensitivity to shear stress in post-menopausal women.

Detailed Description
-----------------
Cardiovascular diseases (CVD) have remained the leading cause of death globally for the last 15 years. Considering that advancing age is the primary risk factor for CVD, an increasingly aging population is expected to result in unprecedented levels of CVD. It therefore remains crucial to develop effective prevention or treatment strategies to reduce the impending health and economic burden of CVD. Exercise is arguably the best intervention for the prevention and/or treatment of CVD. A key adaptation underlying the cardiovascular benefits of exercise is to offset and reverse age-related reductions in vascular function. Studies have demonstrated, at least in men, that active older adults demonstrate preserved vascular function relative to their sedentary peers and that exercise training interventions improve vascular function in previously sedentary older adults. However, these studies have almost exclusively been performed in men. In contrast, the few studies performed in older women consistently demonstrate that active women do not demonstrate preserved vascular function relative to their sedentary peers and that exercise training interventions do not improve vascular function in previously sedentary women. This observation has been attributed to the loss of oestrogens that accompanies menopause. Although the mechanisms have not been fully elicited, it is possible that the loss of oestrogens desensitizes the endothelium to the physiological stimuli that result in improved vascular function with exercise training. Indeed, exercise improves vascular function in previously sedentary older women when it is combined with oestrogen replacement. Nevertheless, chronic oestrogen replacement therapy is not a viable intervention as it is associated with an increased risk of breast cancer. Alternative solutions to restore the beneficial effects of exercise on vascular function in post-menopausal women are thus urgently needed. The overall objective of this project is to determine if folic acid, an over-the-counter supplement that has been shown to provide beneficial vascular adaptations, can be used to improve vascular function in post-menopausal women. It is hypothesized that folic acid will improve blood vessel function in post-menopausal women and age-matched males.

Official Title
-----------------
An Evaluation of Folic Acid to Improve Endothelial Sensitivity to Shear Stress in Post-menopausal Women.

Conditions
-----------------
Healthy Aging, Aging, Menopause

Intervention / Treatment
-----------------
* Dietary Supplement: Folic Acid
* Other: Placebo


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: ≥ 1-year amenorrhea Body mass index ≤ 30 kg/m2 Resting blood pressure < 140 / < 90 mmHg Non-smoker (≥ 1-year) Exclusion Criteria: Diagnosis of cardiac, vascular, respiratory, neurological or metabolic disease and/or a prescription of medications for the treatment of such diseases. For female participants, hormonal replacement therapy within 1 year of enrolment in the study. For female participants, having undergone an ovariectomy.

Ages Eligible for Study
-----------------
Minimum Age: 50 Years
Maximum Age: 80 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Placebo treatment<br>Participant will be asked to ingest a placebo capsule. | Other: Placebo<br>* Placebo capsule<br>|
| Experimental: Folic Acid<br>Participant will be asked to ingest a capsule containing 5 mg of folic acid. | Dietary Supplement: Folic Acid<br>* Folic acid (5 mg)<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelial sensitivity to shear rate | Change in brachial artery diameter for given levels of shear rate during rhythmic handgrip exercise | Measured 2 hours after placebo or folic acid consumption | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Neurovascular transduction | Change in femoral artery diameter for a given increase in muscle sympathetic nerve activity during isometric handgrip exercise to fatigue. | Measured 2 hours after placebo or folic acid consumption | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Postmenopausal women, Vascular health, Folic acid