Title

Evaluating the Roles of Estrogen and Progesterone in Heart Metabolism
Role of Estrogen/SERMS on Cardiac Fatty Acid Metabolism (Aim #1- Human Studies)
  • Phase

    N/A
  • Study Type

    Interventional
  • Study Participants

    22
Estrogen and progesterone are two main female sex hormones. When a woman goes through menopause, the body's production of estrogen and progesterone significantly decreases. Recent studies have shown that the breakdown of fatty acids in cardiac muscle is important in maintaining a healthy heart, and that estrogen may enhance this process. Also, cardiovascular disease (CVD) occurs more frequently in postmenopausal women than in premenopausal women. This study will determine in postmenopausal women whether estrogen increases the heart's ability to use fats as energy and whether progesterone decreases this effect.
Menopause is a natural event that generally occurs in women between the ages of 45 and 55. During menopause, the body starts producing less estrogen and progesterone until menstruation eventually stops. Estrogen and progesterone are involved in many important functions in a woman's body, and the drastic decline of these hormones in menopause leads to significant changes in the body. Along with such changes, postmenopausal women are at a higher risk than premenopausal women for certain health problems, such as CVD. Previous studies have revealed that alterations in the breakdown of fatty acids in cardiac muscle play a key role in a variety of cardiac disorders. In studies involving human skeletal muscle, estrogen has been shown to increase the breakdown of fatty acids, while progesterone lessens this effect. This study will determine in postmenopausal women whether estrogen increases the heart's ability to break down fats for energy use and whether progesterone decreases this effect. This study will also analyze ovariectomized mice to determine if the candidate specific estrogen receptor modulators (SERMs) raloxifene and tamoxifen increase the heart's ability to use fats as energy and whether the increase is similar to that seen with estrogen. Study investigators will also create estrogen receptor knock-out mice (mice with estrogen receptors removed) to further explore the roles of estrogen and SERMs in heart metabolism.

Participation in this double-blind study will last up to 1 month and will include three study visits. During Visit 1, participants will undergo three standard clinical evaluations. The first evaluation, a medical screening, will include a medical history exam and blood tests to measure estrogen and progesterone levels, liver and kidney function, cholesterol levels, and blood sugar and insulin levels. For the second evaluation, participants will undergo a body composition study to measure total body fat and muscle content using a dual-energy x-ray absorptiometry (DEXA) scan. During the third evaluation, participants will undergo an electrocardiogram (ECG) and an echocardiogram (ECHO), each performed immediately before and after walking on a treadmill. The ECG will measure electrical activity of the heart, and the ECHO will involve imaging the heart with an ultrasound.

Visits 2 and 3, occurring 3 days apart, will each include two imaging tests of the heart: a positron-emission tomographic (PET) scan and a resting ECHO. Throughout both tests an ECG and blood pressure cuff will be used to monitor heart rhythm and blood pressure, respectively. During the PET scan, participants will lie flat in an imaging machine for three 45- to 60- minute intervals. Blood will be drawn and radioactive tracers will be injected via intravenous lines placed in the arms. The ECHO test will also be done during the PET scan.

Between Visits 2 and 3, participants will be randomly assigned to one of two hormone replacement therapy (HRT) regimens: estrogen plus placebo or estrogen plus progesterone. All participants will wear a patch containing estrogen and take a pill of either placebo or progesterone for the 3 days leading up to Visit 3. All participants will be asked for permission to store a sample of their blood for up to 10 years to be used in future research studies.
Study Started
Aug 31
2004
Primary Completion
Jan 31
2008
Study Completion
Jan 31
2008
Results Posted
Oct 16
2018
Last Update
Oct 16
2018

Drug Estrogen

Estrogen only plus placebo: estradiol topical patch 0.3 mg placed on the lower abdomen for 3 days plus an oral placebo. Other procedures: heart metabolism tests which includes a positron-emission tomography (PET) scan, an electrocardiogram (ECG), and an echocardiogram (ECHO).

  • Other names: Estradiol

Drug Progesterone

Estrogen plus progesterone: estradiol with oral progesterone (Prometrium, 200 mg/day) for 3 days, instead of placebo. Progesterone therapy involves taking a daily oral pill of 200 mg Prometrium for the same 3 days that the estradiol is taken.

  • Other names: prometrium

Drug Placebo

Placebo progesterone therapy involves taking a daily placebo pill for the same 3 days that the estradiol is taken.

  • Other names: Inactive Drug

estrogen plus progesterone Experimental

Hormone replacement therapy (HRT): estrogen plus progesterone

estrogen plus placebo Active Comparator

Hormone replacement therapy (HRT): estrogen plus placebo

Criteria

Inclusion Criteria:

Healthy postmenopausal woman
Body mass index less than 30
Practices normal eating habits
Stops hormone replacement therapy at least 6 months prior to study entry

Exclusion Criteria:

Currently taking hormone replacement therapy
History of cardiovascular disease
Family history of coronary artery disease
Recent history of smoking, high blood pressure, or hyperlipidemia

Summary

Estrogen Plus Progesterone

Estrogen Plus Placebo

All Events

Event Type Organ System Event Term

Number of Participants That Had an Increase in Myocardial Fatty Acid Utilization.

Measurements of myocardial fatty acid utilization and oxidation with C[11]-Palmitate and PET in healthy postmenopausal women who take either estrogen alone or with progesterone. The primary outcome measure was designed to determine prospectively whether estrogen will increase the heart's fatty acid utilization and whether progestins will attenuate this effect, in a manner similar to what was seen in an observational study of hormone replacement therapy (HRT) in post-menopausal women. To this end, we had anticipated enrolling 30 healthy post-menopausal women for assessment of cardiac fatty acid metabolism using positron emission tomography (PET) and radioactive C[11]-Palmitate both before and after 3 days of hormone replacement therapy. These volunteers were to be randomized to receive either estrogen alone (E) or combined estrogen/progesterone (EP).

Estrogen Plus Progesterone

Estrogen Plus Placebo

Total

22
Participants

Age, Categorical

Sex: Female, Male

Overall Study

Hormone Replacement Therapy (HRT): Estrogen Plus Progesterone

Estrogen Plus Placebo