The purpose of this study is to identify the impact of estradiol (E2) on the associations between (a) responsivity to daily stress or (b) sleep variability with vascular function in midlife premenopausal women.
In the last 20 years, deaths due to cardiovascular disease (CVD) have increased by up to 30% in midlife women. This increase in CVD risk in midlife women is at least partially explained by the declines in estradiol (E2) that occur across the menopausal transition. This loss of E2 induces vascular dysfunction, a major contributor to increased CVD risk. Nevertheless, we have shown that declines in vascular function are evident in some midlife premenopausal women, suggesting that vascular dysfunction-associated CVD risk cannot solely be explained by the loss of E2. Emerging factors that may help explain vascular dysfunction in midlife women include greater emotional vulnerability to daily stressors and poorer sleep health. However, not yet know is the extent to which daily stress and sleep health independently impact vascular function in midlife premenopausal women or the degree to which these associations are influenced by E2. The objective of this project is to test the central hypothesis that (a) greater negative affective responsivity to daily stressors and (b) greater sleep variability will each be related to more severe declines in vascular function in midlife premenopausal women and that these associations will be magnified during E2 suppression (simulated menopause) compared to the follicular phase of the menstrual cycle/placebo phase of hormonal contraception. We will assess affective responsitivy to daily stressors and device-measured sleep characteristics for 10 consecutive days and cutaneous microvascular endothelial function before and during pharmacological E2 suppression. The investigators will assess multiple dynamic aspects of daily stress processes for 10 consecutive days (mobile app). Investigators will concurrently objectively assess sleep variability (ActiGraph wGT3X). Immediately before and after completion of these ambulatory assessments, Investigators will assess microvascular endothelial function using intradermal microdialysis coupled with laser Doppler flowmetry. Participants will complete two 10-day measurement bursts:The first will occur during the follicular phase of their menstrual cycle or the low hormone/placebo phase of hormonal contraception; The second will occur during supression of endogenous ovarian hormone production via GnRH antagonist ganirelix acetate.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
NONE
Enrollment
30
Ganirelix acetate (Antagon) will be used to prevent endogenous production of ovarian hormones in young women. Ganirelix is derived from native GnRH, and acts by competitively blocking GnRH receptors on the pituitary and subsequent pathways. Thus, administration of the GnRH antagonist (GnRHant) suppresses steroidogenesis, leading to low or undetectable serum estrogen and progesterone concentrations, which occurs within two days of initiation of administration. Women will self-administer subcutaneous injections (0.25 mg/day in 0.5 ml of normal saline) of the GnRH antagonist ganirelix acetate (Antagon, Organon, Inc., West Orange, New Jersey,) every day for \~12-15 days (starting on day \~2-4 of the menstrual cycle). Testing will occur on day 3-4 and day14-15 of using Antagon.
University of Delaware
Newark, Delaware, United States
RECRUITINGEndothelium-dependent dilation (EDD)
EDD will be calculated as the area under the dose-response curve (AUC) to ascending concentrations of acetylcholine.
Time frame: Immediately before and after each 10-day measurement burst
Negative affective response to daily stressors
Within-person composite slope between daily stressors and daily negative affect
Time frame: 10-day measurement burst
Sleep variability
Sleep onset standard deviation (minutes) estimated via actigraphy
Time frame: 10-day measurement burst
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