Brown Adipose Tissue Activity in Pre- and Postmenopausal Women
| Status: | Recruiting |
|---|---|
| Conditions: | Obesity Weight Loss, Women's Studies |
| Therapuetic Areas: | Endocrinology, Reproductive |
| Healthy: | No |
| Age Range: | 18 - 99 |
| Updated: | 7/28/2018 |
| Start Date: | January 2017 |
| End Date: | August 2019 |
| Contact: | Tracy Swibas, M.S. |
| Email: | tracy.swibas@ucdenver.edu |
| Phone: | (303) 724-6418 |
The Impact of Estrogen Status on the Biological Function of Brown Adipose Tissue in Women Measured Using Quantitative PET/CT
The physiological relevance of brown adipose tissue (BAT) in humans is largely unknown. The
investigators have shown that suppressing ovarian function in premenopausal women reduces
resting energy expenditure (REE), and this is prevented by adding back estradiol (E2). The
investigators preliminary data suggest that this may be due, in part, to reduced brown
adipose tissue (BAT) activity. The overarching hypothesis is that BAT activity in humans is
modulated by E2. To determine if natural declines in endogenous E2 contribute to changes in
BAT activity, we will compare BAT activity in pre-and post-menopausal women. The
investigators will also explore whether suppression of ovarian hormones in pre-menopausal
women impairs BAT activity. BAT activity will be quantified using dynamic positron emission
topography/computed tomography (PET/CT) imaging combined with 11C-acetate tracers. We will
assess the thermogenic response of BAT by measuring cold-induced changes in REE, shivering,
and skin and core temperature.
investigators have shown that suppressing ovarian function in premenopausal women reduces
resting energy expenditure (REE), and this is prevented by adding back estradiol (E2). The
investigators preliminary data suggest that this may be due, in part, to reduced brown
adipose tissue (BAT) activity. The overarching hypothesis is that BAT activity in humans is
modulated by E2. To determine if natural declines in endogenous E2 contribute to changes in
BAT activity, we will compare BAT activity in pre-and post-menopausal women. The
investigators will also explore whether suppression of ovarian hormones in pre-menopausal
women impairs BAT activity. BAT activity will be quantified using dynamic positron emission
topography/computed tomography (PET/CT) imaging combined with 11C-acetate tracers. We will
assess the thermogenic response of BAT by measuring cold-induced changes in REE, shivering,
and skin and core temperature.
Participants will be asked to perform studies to measure resting metabolic rate and activity
of brown adipose tissue or brown fat. Brown fat is different from regular "white fat" in that
it produces heat and burns calories. The investigators will measure how active brown fat is
at normal room temperature and after participants have been exposed to cold.
The study will last 5-6 hours. It will consist of measurements made in warm temperatures and
then after a period of cold exposure. For the cold exposure part of the study, participants
will be asked to wear a cooling suit for 3 hrs. Skin temperature is normally about 90º
Fahrenheit. The cooling suit will adjust the water temperature until your skin temperature is
about 82º Fahrenheit. The suit will cover the entire body except for the face, hands, and
feet. Participants may feel cold while wearing the suit and you may shiver some, but based on
past studies, any shivering should be minor.
Before and after the cooling suit is turned on, body scans will be performed using a
procedure called positron emission tomography (PET). These scans do not use radiation. Before
the PET scans, the investigators will infuse radioactive tracer into an arm. These tracers
have a low dose of radiation and will show us where the brown fat is and how active it is.
One PET scan will be performed at room temperature, and the second scan will be performed
after the cooling suit has been worn for 3 hours. Two additional scans using computed
tomography (CT) will be performed at end of the study. CT scans are like an x-ray, and use
radiation. The radiation dose in the CT scan is much higher than the tracers. When the CT
scans are combined with the PET scans, we can separate brown fat from white fat.
15 pre-menopausal women will be asked to volunteer for a follow up study. For 5 months,
pre-menopausal women in this study will receive monthly injections that contain a study drug
(leuprolide) that reduces estrogen to postmenopausal levels. This drug is approved by the FDA
to reduce estrogen for the treatment of uterine fibroids and endometriosis, but is not
approved for use in healthy women. In this study, the drug is being used to decrease hormones
to determine if this reduces brown fat activity. 6 months after the first injection, these
women will be asked to repeat the PET/CT studies.
of brown adipose tissue or brown fat. Brown fat is different from regular "white fat" in that
it produces heat and burns calories. The investigators will measure how active brown fat is
at normal room temperature and after participants have been exposed to cold.
The study will last 5-6 hours. It will consist of measurements made in warm temperatures and
then after a period of cold exposure. For the cold exposure part of the study, participants
will be asked to wear a cooling suit for 3 hrs. Skin temperature is normally about 90º
Fahrenheit. The cooling suit will adjust the water temperature until your skin temperature is
about 82º Fahrenheit. The suit will cover the entire body except for the face, hands, and
feet. Participants may feel cold while wearing the suit and you may shiver some, but based on
past studies, any shivering should be minor.
Before and after the cooling suit is turned on, body scans will be performed using a
procedure called positron emission tomography (PET). These scans do not use radiation. Before
the PET scans, the investigators will infuse radioactive tracer into an arm. These tracers
have a low dose of radiation and will show us where the brown fat is and how active it is.
One PET scan will be performed at room temperature, and the second scan will be performed
after the cooling suit has been worn for 3 hours. Two additional scans using computed
tomography (CT) will be performed at end of the study. CT scans are like an x-ray, and use
radiation. The radiation dose in the CT scan is much higher than the tracers. When the CT
scans are combined with the PET scans, we can separate brown fat from white fat.
15 pre-menopausal women will be asked to volunteer for a follow up study. For 5 months,
pre-menopausal women in this study will receive monthly injections that contain a study drug
(leuprolide) that reduces estrogen to postmenopausal levels. This drug is approved by the FDA
to reduce estrogen for the treatment of uterine fibroids and endometriosis, but is not
approved for use in healthy women. In this study, the drug is being used to decrease hormones
to determine if this reduces brown fat activity. 6 months after the first injection, these
women will be asked to repeat the PET/CT studies.
Inclusion Criteria:
- Premenopausal volunteers will be healthy, eumenorrheic women, aged 18-45 yrs.
Eumenorrheic status will be verified by regular menses (no missed cycles in previous
year; cycle length 25-35 d).
- Postmenopausal volunteers will be healthy women who have no menses for at least 12
months
Exclusion Criteria:
- Body mass index (BMI) > 35 kg/m2
Additional exclusion criteria for premenopausal women
- Hormonal contraceptive use (past 6 mo.)
- Pregnant, lactating or intention to become pregnant during the period of study
Additional exclusion criteria for postmenopausal women
- History or current use of hormonal replacement therapy (HRT)
- Women who have undergone surgical menopause.
We found this trial at
1
site
13001 E 17th Pl
Aurora, Colorado 80045
Aurora, Colorado 80045
(303) 724-5000
University of Colorado Anschutz Medical Campus Located in the Denver metro area near the Rocky...
Click here to add this to my saved trials
