NCT03236545

Menopause Effects on Vascular Function

Mechanisms of Vascular Dysfunction in Women: Role of Estradiol

• Status: Completed
• Phase: N/A
• Study type: Interventional
• Enrollment: 48 (actual)
• Sponsor: University of Delaware · Academic / Other
• Sex: Female
• Age: 18 Years – 65 Years
• Healthy volunteers: Accepted

Summary

The purpose of the study is to identify the independent effect of estradiol (E2) on endothelin-1 (ET-1) mediated vasomotor function in women. The study is the first step in recognizing the impact of ovarian hormones on the mechanisms that regulate vascular function in women to provide a better understanding of the cardiovascular efficacy of hormone therapy.

Detailed description

Cardiovascular disease (CVD) is the leading cause of death in women (Roger, Go, Lloyd, Adams, Berry, Brown, et al, 2011). Functional changes in the microvasculature occur with aging and precede atherosclerosis, contributing to CVD (Seals, Jablonski, \& Donato, 2011). Furthermore, because of the decline in ovarian hormones during menopause, age-related impairments in endothelial function are exacerbated in postmenopausal women (PMW). However, the safety and efficacy of currently available hormone-based therapies remains controversial (Devi, Sugiguchi, Pederson, Abrassart Glodowski, \& Nachtigall, 2013: Miller, Black, Brinton, Budoff, Cedars, Hodis, et al, 2009). Endothelin-1 (ET-1) is a potent vasoconstrictor produced and released by endothelial cells and implicated in the development of atherosclerosis (Best, McKenna, Holmes, \& Lerman, 1999; Donato, Gano, Eskurza, Silver, Gates, Jablonski, et al, 2009; Ihling, Szombathy, Bohrmann, Brockhaus, Schaefer, \& Loeffler, 2009). ET-1 binds to two receptor subtypes, ET-A and ET-B (Yanagisawa, Kurihara, Kimura, Tomobe, Kobayashi, Mitsui, et al, 1988). While both receptors are located on vascular smooth muscle (VSM) and cause vasoconstriction, ET-B receptors are also located on the endothelium and cause vasodilation (Gomez-Sanchez, Cozza, Foecking, Chiou, \& Ferris, 1990; Haynes, 1995; Ishikawa, Ihara, Noguchi, Mase, Mino Saeki, et al, 1994). In women, ET-1 preferentially binds to ET-B receptors compared to ET-A receptors, supporting findings of sex differences in ET-1 receptor responses and suggesting ET-B receptors are under hormonal control (Ergul, Shoemaker, Puett, \& Tackett, 1998; Kellogg, Liu, \& Pergola, 2001; Stauffer, Westby, Greiner, Van Guilder, \& Desouza, 2010). In animal models, estradiol (E2) reduces ET-1 mediated vasoconstriction and increases ET-B receptor mRNA (Pederson, Nielsen, Mortensen, Nilas, \& Ottesen, 2008). Thus, low levels of E2 in PMW may contribute to impaired vascular function through an ET-B receptor mechanism. However, the interaction between E2 and ET-1 receptor responses on regulating vascular function in women is currently unknown. The long-term goal of the laboratory is to understand the impact of ovarian hormones on the mechanisms that regulate vascular function in women to provide a better understanding of the cardiovascular efficacy of hormone therapy. The study is the first step in reaching our goal; the objective of the study is to identify the independent effect of E2 on ET-1 mediated vasomotor function in women. The investigators will measure blood flow responses to local heating in the cutaneous circulation during perfusion of ET-1 receptor antagonists via microdialysis, coupled with measures of intracellular protein and receptor expression on endothelial cells and skin punch biopsies (to assess VSM cells) collected from young and PMW while controlling ovarian hormone exposure. Young women will be tested after suppressing ovarian production of E2 and progesterone with a gonadotropin-releasing hormone antagonist (GnRHant), and again after E2 administration; PMW, who are not using hormone therapy, will be tested before and after E2 admin. The central hypothesis is that declines in E2 impair microvascular vasodilatory function due to cellular changes in ET-B receptor expression on endothelial and VSM cells, and that E2 administration reverses these responses.

Conditions

• Cardiovascular Risk Factor

Interventions

Type	Name	Description
OTHER	No to Low Endogenous Estrogen	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 (Oberye, Mannaerts, Huisman \& Timmer, 1999; Oberye, Mannaerts, Kleijn, \& Timmer, 1999).
OTHER	Estradiol	Short term estradiol administration elicits changes in vascular function in women, and 0.1mg/day patch is the upper recommended limit for hormone therapy in women (Wenner, Taylor, \& Stachenfeld, 2011; Moreau, Hildreth, Meditz, Deane \& Kohrt, 2012).

Timeline

• Start date: 2016-07-01
• Primary completion: 2022-04-30
• Completion: 2022-11-01
• First posted: 2017-08-02
• Last updated: 2022-11-14

Locations

1 site across 1 country: United States