Impact of Estradiol on Endothelial Function in Peri-Menopausal Women

Study Overview
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Brief Summary
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The purpose of this study is to identify the impact of estradiol (E2) on the mechanisms that regulate vascular endothelial function in peri-menopausal (PERI) women. This study is the first step in understanding factors contributing to endothelial dysfunction in women with advancing reproductive age and in response to E2 administration.

Detailed Description
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Cardiovascular disease (CVD) is the leading cause of death in women. Although overall CVD-related mortality has declined, there has been an increase in CVD mortality in women aged 35-54 years, prior to menopause. It is unclear what contributes to this increased mortality rate, and is a significant problem for women's health. Endothelial function is considered a biomarker of cardiovascular health; declines in endothelial function are considered a precursor to the development of atherosclerosis and CVD. Thus, changes in endothelial function in women as they advance through reproductive stages towards menopause may play a role in the greater prevalence of CVD mortality. However, very few studies have focused on cardiovascular health in women leading up to menopause, during the PERI transition. The PERI period is a critical time point where reproductive hormones and ovarian function change rapidly. Recent data demonstrate that endothelial function begins to decline during PERI. Furthermore, despite women being of similar biological age, significant differences in endothelial function were noted when classified based on reproductive age - specifically between early PERI and late PERI. These data show that the decline initially occurs in the early PERI phase, making this a key time point for intervention to offset the future development of CVD. Our central hypothesis is that increased Endothelin-1 (ET-1) and a loss of Endothelin-1 B (ETB) mediated vasodilation play a primary role in contributing to impaired endothelial function with advancing reproductive age. We will assess macro- and micro- vascular endothelial function, assess intracellular ET-1 protein and ETB receptor expression in harvested endothelial cells from peripheral veins, and use the cutaneous circulation as an in vivo model to explore the receptor mechanisms (ETBR and ETAR) in early and late PERI in response to E2 or placebo.

Official Title
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Impact of Estradiol on Endothelial Function in Peri-Menopausal Women

Conditions
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Perimenopause, Vasodilation, Estrogen

Intervention / Treatment
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* Drug: Estradiol (mylan or vivelle dot patch)
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Peri-menopausal women between 40-58 years of age with variable cycles as defined by increase in cycle length of greater than 7 days within ten consecutive cycles, or amenorrhea for more than 2 months, but less than 12 months. Exclusion Criteria: Women who are pregnant, planning on becoming pregnant, or are breast feeding; Women who have a history of cardiovascular disease, blood clots (e.g, pulmonary embolism or deep vein thrombosis), stroke, cancer, or liver disease; Women who have a body mass index less than 18 or greater than 35kg/m2; Women who use tobacco products; Women who's blood pressure is greater than 140/90 mmHg, have been diagnosed by a physician with hypertension or are taking medication for high blood pressure; Women who have a neurological disease, or diabetes; Women who have had a hysterectomy or have used hormones (birth control or hormone replacement) within the past 3 months; Women who have a latex allergy.

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 58 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Estradiol<br>Transdermal estradiol (0.1mg/day patch) | Drug: Estradiol (mylan or vivelle dot patch)<br>* Transdermal estradiol (0.1mg/day patch) will be used by women for 7 days. Administration of the patch will follow the package guidelines to change the patch after 3-4 days of use.<br>|
| Placebo Comparator: Placebo<br>Placebo | Other: Placebo<br>* A placebo patch that is visually similar to the estradiol patch will be used for the group not receiving estradiol.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Vascular Endothelial Function (Flow mediated dilation or FMD) | The capacity of the large and small blood vessels to dilate. | Change in FMD from Baseline to Day 7 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Endothelial Cell Protein Expression | Venous endothelial cells will be harvested from peripheral veins of women during the hormone intervention and stained for expression of ET-1 and ETB receptors. | Change in fluorescent intensity from Baseline to Day 7 | 
| Endothelin Receptor Responses | The contribution of Endothelin A (ETA) and Endothelin B (ETB) receptors on changes in endothelial function will be assessed in the cutaneous circulation via microdialysis. Blood flow responses to local heating will be assessed under control and blockade sites in women during estradiol or placebo administration. | Change from Baseline to Day 7 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Perimenopause, Vasodilation, Estrogen