32 Clinical Trials for Various Conditions
Brown fat is a type of fat, found in both children and adults, which can produce heat and regulate the body's metabolism and energy use. White fat is the more common type of fat which is used to store extra calories. Understanding more about differences between brown and white fat may allow us to develop new approaches to improve the body's metabolism.
Brown adipose tissue is poorly understood fat that can metabolize glucose in order to generate heat. Since activated brown fat has a high metabolic rate, it is of great interest as a potential target to combat obesity. However, the signaling and control of brown fat metabolism is poorly understood. Because brown fat uses glucose as its energy source, brown fat metabolism can be imaged with PET/CT using the positron emitting glucose analog F-18 FDG. We have recently shown in mice a striking circadian variation in brown fat metabolism as evidenced by changes in FDG uptake. In this study we endeavor to generate pilot data on a potential circadian variation in brown fat activation in healthy humans.
This study will test the hypothesis that human brown adipose tissue (BAT) can be activated using a β3-adrenergic receptor (AR) agonist. The efficacy of β3-AR agonist will be compared with cold exposure, which we have already shown can activate human BAT, as well as a placebo control.
This clinical trial will assess the whether fish oil supplementation can modulate brown fat activation, shivering, thermal comfort and skin blood flow during cold exposure.
Excess fetal adipose tissue growth during intrauterine development increases future obesity risk. Development of brown adipose tissue, a highly thermogenic organ in utero, may affect postnatal energy expenditure, thus influencing obesity risk. This pilot research study is designed to understand the developmental origins of energy balance by examining maternal and neonatal factors that influence neonatal brown adipose tissue and to quantify its physiological relevance to energy expenditure in human neonates.
Glucagon like peptide (GLP-1) agonists, such as liraglutide, exenatide, and semaglutide, have been increasingly used as a medication to address the current twin epidemics of diabetes and obesity. Their activities include increasing insulin production by pancreatic beta cells, improving insulin sensitivity in muscles and weight loss. The mechanisms underpinning the weight loss caused by GLP-1 agonists have not yet been fully elucidated, but brown adipose tissue (BAT) appears to play an important role. We propose to assess BAT activity, using infrared thermography camera images, before individuals start weekly administration of semaglutide, at week 2-4, and week 18-20. We hypothesize that this GLP-1 agonist, semaglutide, will cause an increase in BAT activity and a corresponding increase in basal metabolic rate.
The objective of this study is to investigate and utilize spinal cord stimulation (SCS) as an effective approach to eliciting weight loss and potentially alleviating Type 2 diabetes mellitus (DM), as evidenced by increasing metabolism of adipose tissue.
The goal of this study is to define the effect of aging on brown adipose tissue mass in a cohort of older sedentary and older athlete adults.
The primary purpose of this protocol is to develop a reliable method to determine BAT mass in young and older adults by magnetic resonance imaging.
This research study is being done to determine whether taking a dietary supplement called capsinoids, derived from sweet peppers, can activate brown fat that is already present or even generate new brown fat in individuals with excess weight. Previous studies have suggested that chronic consumption of capsinoids may be able to generate new brown fat in thin individuals. Capsinoids may also have a small positive effect on metabolism (increased calorie-burning) and fat loss. The knowledge gained in this study may eventually lead to more treatment options for people with excess weight.
Background: Brown adipose tissue (BAT) is a type of fat in the body. It may prevent weight gain, improve insulin sensitivity, and reduce fatty liver. Researchers want to see if BAT helps the body burn energy. Objective: To learn more about how BAT works to burn energy. Eligibility: People ages 18-40 with a body mass index between 18 and 40 Design: Participants will be screened with: Medical history Physical exam Blood, urine, and heart tests Dietitian interview Participants will have an overnight baseline visit. This includes: Repeats of screening tests Exercise test Scans. For one scan, a radioactive substance is injected into the arm. FSIVGIT: An IV is inserted into veins in the right and left arms. Glucose and insulin are injected in one arm. Blood glucose and insulin levels are measured from the other. Metabolic suite: Participants stay 18 19 hours in a room that measures their metabolic rate. Monitors on the body measure heart rate, movement, and temperature. Optional fat biopsy: A small piece of tissue is removed with a needle. Participants will take 2-4 pills daily for 4 weeks. All women will take the drug mirabegron. Men will be randomly get either the drug or a placebo. All participants will have a visit after 2 weeks of the pills. They will repeat the screening tests. Participants will have an overnight visit 2 weeks later. They will repeat the baseline tests. Participants will keep food and medication diaries. Participants will have a follow-up visit 2 weeks after stopping the pills. This includes heart tests. ...
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.
The recent discovery of functional brown adipose tissue (BAT) in humans has led to a paradigm shift in adipose tissue biology; it is now believed that adipocytes may play a significant role in regulating substrate metabolism. Given that the resurgence in the interest in human BAT is still in its infancy, a number of fundamental questions pertaining to the role of BAT in human physiology remain unanswered. One area of particular importance, but poorly understood, is the potential effect of BAT on triglyceride (TG) metabolism. Data from a series of studies have found that BAT is inversely associated with adiposity, high blood lipids, and fatty liver in people. However, the role of BAT in the regulation of TG metabolism in people is not known. The overall goal of this study is to determine the physiological importance of the human BAT in TG metabolism. To this end, we are planning to study overweight/obese women with high amounts of BAT (BAT+, n=14) and with no/minimal BAT (BAT-, n=14) both under thermoneutrality and mild cold exposure (\~2 weeks apart). The investigators hypothesize that BAT+ participants will demonstrate greater plasma very low-density lipoprotein triglycerides (VLDL-TG) clearance rate compared to BAT- participants, and higher expression of genes involved in lipid metabolism only in BAT (but not muscle and white adipose tissue). Infusion of stable isotope tracers and metabolic modeling techniques will be used to assess VLDL-TG kinetics. Positron emission tomography computed tomography will be used for the identification and quantification of BAT. Supraclavicular BAT, abdominal white adipose tissue, and skeletal muscle tissue biopsies during cold exposure and thermoneutral conditions in conjunction with molecular biology techniques will used to measure expression of genes involved in lipid metabolism.
The primary goal of this study is to assess the accuracy of conventional fat fraction proton MRI for the detection of Brown Adipose Tissue (BAT) in healthy subjects using 18F-2-fluoro-2-deoxy-D-glucosefluorodeoxyglucose -PET as gold standard. In this pilot study, MRI and PET imaging of BAT of healthy adult volunteers will be performed on a combined PET/MRI scanner under mild cold condition.
This is a single-arm, open-label study to assess the safety and effectiveness of a single dose of oral propranolol in reducing18F-fluorodeoxyglucose (FDG) uptake in brown adipose tissue (BAT) in pediatric oncology patients. This study is designed to better understand if taking a single dose of an oral medication called propranolol can reduce the chance of brown fat showing up on a PET scan, and therefore make the scan more accurate and easy to interpret. All humans have some degree of normal brown fat (called brown adipose tissue), and this normal tissue can sometimes light up on a PET scan. That creates problems because it may be wrongly interpreted by the radiologist as tumor, or it may hide true areas of tumor underneath it. Participants will not be randomized and will receive a single dose of oral propranolol approximately 60 minutes prior to the injection of the FDG tracer. The dose of propranolol will be 20 mg for all participants.
This study seeks to assess a novel imaging technique to image brown adipose tissue utilizing the norepinephrine transporter.
Recent findings document the presence of active brown adipose tissue (BAT) in humans. Cold exposure via adrenergic stimulation activates BAT, which combusts significant amounts of blood glucose and free fatty acid (FFA) to produce heat. Animal studies suggest that BAT activation improves insulin sensitivity. However, the effect of cold-induced BAT activation on insulin sensitivity and glucose kinetics in humans remains unknown. The investigators' central hypothesis is that cold-induced BAT activation increases whole body insulin sensitivity in humans via augmented plasma glucose and FFA clearance. The specific aims of this study are to define the effects of prolonged (8h) cold exposure BAT activation on: insulin sensitivity (Aim 1); lipolysis and plasma glucose and FFA kinetics (Aim 2); on thermoregulation (Aim 3). Moreover, the investigators plan to investigate for alternative ways, which can activate BAT including cold water ingestion, a single meal ingestion, and a single bout of moderate intensity exercise (Aim 4). For the cold exposure study, subjects will complete 3 trials: a) 8hrs of cold exposure at their individually determined shivering threshold; b) 8hrs of cold exposure at their individually determined shivering threshold plus propranolol; c) 8hrs in thermoneutral conditions (26 - 28°C). For the rest of the arms of subjects will complete two trials: cold or tepid water ingestion, a single meal ingestion or no food ingestion, and a single bout of moderate intensity exercise or no exercise.To study the above aims, the investigators will use positron emission tomography - computed tomography, hyperinsulinemic euglycemic clamp, infusion of stable isotopes, and tissue biopsies. The findings will illuminate the role of BAT on plasma substrate regulation and insulin sensitivity and may aid in the development of lifestyle recommendations and pharmacotherapy for the prevention and treatment of diabetes and insulin resistance.
Androgen deprivation therapy (ADT) is considered standard of care for prostate cancer. However, changes in the patients metabolism are usually seen as a result of hormone therapy. These changes include increased fat mass, decreased lean mass, weight gain, high blood cholesterol, increased incidence of diabetes, and possibly increased incidence of cardiac events such as heart attack. The researchers of this trial would like to learn if these change in body mass are affected by the presence of brown fat in the body. Brown fat is made up of fat cells that are stored in the body and generate heat to control body temperature. Levels of brown fat are at the highest in newborn babies and decrease over time into adulthood. The researchers of this trial would like to learn more about these changes in metabolism during prostate cancer treatment by studying the changes in brown fat during the first 12 months of hormone therapy.
Up to 10 infants will complete the study aimed to establish a technique for measuring whole body adiposity and brown adipose tissue in infant subjects using dual energy x-ray absorptiometry and magnetic resonance imaging, respectively.
Background: The body uses energy from calories for basic functions like breathing and digesting food. Over time, when a person eats more calories than they burn, they may become overweight or obese. Obesity is a major health concern. Researchers want to look at fat and muscle tissue to learn more about metabolism. That is how the body uses food and other nutrients for normal function and energy. This research may help to develop new treatments for obesity and related diseases. Objective: To learn more about the role of fat and muscle in metabolism, particularly how fat and muscle store and use energy. Eligibility: Adults 18 years and older who have a planned surgery at NIH in which tissue can be collected by the surgeon. Design: Participants will be screened by their regular NIH doctor. Then researchers will contact them about this study. Participants will not have to make extra visits to NIH for this study. Researchers will collect samples during the participant s surgery. These will be fat tissue and skeletal muscle tissue. Muscle tissue will only be taken from tissue that is going to be discarded. Collecting the tissue will not add any time or any extra incisions than what is required for the surgery. After surgery, blood will be drawn. Some participants will have this done in the pre-op or post-op room. Others will have this done during their hospital stay.
Many Navy diving operations are performed in cold water. Despite technical advances to improve thermal protection for cold water diving, these applications are cumbersome and do not provide complete thermal protection as thermal discomfort is subjectively reported by many Navy divers. Brown adipose tissue is highly thermogenic in humans. Therefore, activation of brown adipose tissue might improve cold water tolerance and lower thermal discomfort during cold water diving operations. Mirabegron is a beta-3-adrenergic receptor agonist that is used to treat overactive bladder. Beta-3-adrenergic receptors are located on the urinary bladder, gallbladder and brown adipose tissue. Recent evidence has demonstrated that acute mirabegron administration increases thermogenesis for \~3 hours in humans. However, it is currently not known which dose of mirabegron can increase thermogenesis for longer durations. It is also not known if mirabegron administration can improve cold water tolerance and thermal discomfort during cold water immersion. Finally, it is not known if mirabegron can increase thermogenesis during sympathetic stimulation. This project will fill these knowledge gaps by determining if acute mirabegron administration will delay the fall in core temperature and the onset of shivering during a progressive cold-water immersion challenge. This study is part of a collection of studies that will show if mirabegron is a potential ergogenic aid that can be used to improve cold water tolerance in Navy divers which will ultimately improve the likelihood of successful missions.
Many Navy diving operations are performed in cold water. Despite technical advances to improve thermal protection for cold water diving, these applications are cumbersome and do not provide complete thermal protection as thermal discomfort is subjectively reported by many Navy divers. Brown adipose tissue is highly thermogenic in humans. Therefore, activation of brown adipose tissue might improve cold water tolerance and lower thermal discomfort during cold water diving operations. Mirabegron is a beta-3-adrenergic receptor agonist that is used to treat overactive bladder. Beta-3-adrenergic receptors are located on the urinary bladder, gallbladder and brown adipose tissue. Recent evidence has demonstrated that acute mirabegron administration increases thermogenesis for \~3 hours in humans. However, it is currently not known which dose of mirabegron can increase thermogenesis for longer durations. It is also not known if mirabegron administration can improve cold water tolerance and thermal discomfort during cold water immersion. Finally, it is not known if mirabegron can increase thermogenesis during sympathetic stimulation. This project will fill these knowledge gaps by determining which dose of mirabegron administration will increase thermogenesis during 6 hours of a mild cold stress challenge. This study is part of a collection of studies that will show if mirabegron is a potential ergogenic aid that can be used to improve cold water tolerance in Navy divers which will ultimately improve the likelihood of successful missions.
Human fat tissue is essentially white fat, the main function of which is to store excess energy intake, and to release it when necessary. Brown fat is far less abundant and is present in the body to burn fat (and thus energy) to generate heat to maintain body temperature around 96 degrees. This phenomenon is called thermogenesis. When humans are exposed to cold on a chronic basis, brown fat expands and becomes more active, and consequently burns more energy. The amount of brown fat is higher during winter, and daily short (20 minutes) exposures to cold might be sufficient to induce its activity. We hypothesized that daily short term (20 minutes) exposure to a cold environment (4 °C) for four weeks increases adaptive BAT-mediated thermogenesis. CIT and DIT will be increased proportionally (the increase in CIT and DIT will be correlated).
The goal of this proposed research is to test the hypothesis that long-term mild sleep restriction (SR), as occurs frequently in adults and adolescents, leads to a positive energy balance and weight gain. Aim 1. To determine the effects of SR, relative to habitual sleep (HS), on food choice and energy intake (EI) in adults at risk of obesity. * Hypothesis 1a. EI, assessed by multiple weekly 24-hour recalls, will be greater during a period of SR relative to HS. This will be mostly due to increased fat and carbohydrate intakes. * Hypothesis 1b. Neuronal responses to food stimuli, assessed by functional MRI (fMRI) after 6 weeks of SR or HS, will indicate increased activity in networks associated with reward and food valuation (insula, orbitofrontal cortex) during a period of SR relative to HS. These responses will be correlated with intakes of high carbohydrate and high fat foods (hypothesis 1a) and neuropeptide Y (NPY). Moreover, activation of the default mode network (DMN) will be suppressed to a lesser extent after SR compared to HS. Aim 2. To determine the effects of SR, relative to HS, on energy expenditure (EE) via independent and complementary approaches. * Hypothesis 2a. EE, assessed by doubly-labeled water (DLW), and physical activity level, monitored daily by actigraphy, will be lower during SR relative to HS. * Hypothesis 2b. Brown adipose tissue (BAT), assessed by positron emission tomography and magnetic resonance combined scanner (PET/MR) using 18F-fluorodeoxyglucose (18FDG-PET) and fat fraction (FF) measurement under cold stimulation, will be greater after SR relative to HS. This would suggest higher adaptive thermogenesis after SR compared to HS. BAT activation will also be correlated with NPY. Aim 3. To determine whether SR alters body weight and adiposity relative to HS. * Hypothesis 3a. SR will lead to weight gain and increased total adiposity, as assessed using magnetic resonance imaging (MRI), relative to HS. * Hypothesis 3b. Increased adiposity after SR will be correlated to an adverse cardio-metabolic risk profile (increased glucose, insulin, triglycerides, leptin, reduced high-density lipoprotein cholesterol and adiponectin) and neuronal responses to food stimuli (Hypothesis 1b), and EE (Hypothesis 2a \& 2b). Failure to stimulate BAT with SR will be associated with greater gain in adiposity.
Background: - Insulin receptor mutation causes high blood sugars and sometimes diabetes complications. Researchers want to see if thyroid hormone helps. Objectives: - To see if thyroid hormone treatment changes how the body handles sugar in people with insulin receptor mutation and improves blood sugar in people with diabetes. Eligibility: - People ages 12 65 with an insulin receptor mutation. Design: * Study part 1:19-day clinic stay. Participants will be monitored for 4 days. Then for 15 days they will take a thyroid hormone pill 3 times a day. Participants will have: * Blood tests. * Heart rate and skin temperature monitored. * All their food provided. * Two 5-hour sessions in a special room. They will wear special clothes and sometimes sit still. * Two small tubes inserted in veins. One will deliver tiny amounts of sugar and fat with a non-radioactive tracer. Participants will also drink water with a tracer. The other tube will collect blood. * A sweet drink. Participants may have finger stick blood sugar tests. * Glucose-monitoring device inserted into body fat for two 24-hour periods. * Adults may have samples of fat and muscle taken. * Heart ultrasound. * PET-CT scan in a machine. An intravenous catheter will be placed in an arm vein. A small amount of radioactive substance will be injected. * DEXA scan of body fat and bone density. * Participants with poorly controlled diabetes will then take thyroid hormone at home for 6 months. They will have blood drawn and sent to the study team monthly. * After about 3 months, they will have an overnight visit. After 6 months, they will have a 4-day visit.
The purpose of the study is to gather tissue (from the neck region), specimens (blood and urine) and medical record data from many patients and store them in one place so that scientists have the information they need to conduct research and learn about new ways to predict, identify and treat illness, specifically those related to obesity and diabetes.
The primary goal of this study is to evaluate the feasibility of detecting Brown Adipose Tissue (BAT) in healthy subjects by using hyperpolarized xenon gas MRI. In this pilot study, MRI of BAT of healthy adult volunteers will be performed at 3 Tesla to assess image quality using a prototype surface coil and pulse sequence following inhalation of hyperpolarized 129Xe (xenon) gas at thermoneutrality and under mild cold condition. The investigators are testing the abilities of xenon MRI to see brown adipose tissue and detect its thermogenic activity.
Background: - Researchers are studying how metabolism and hormone levels change in response to mild changes in environmental temperature. Changes in metabolism may lessen with time because of hormonal adaptations. If this increase in metabolism continues for a longer period, mild cold exposure may cause weight loss. It is unclear whether exposure to a warmer temperature may cause opposite changes in metabolism. Researchers want to see if longer exposure (1 month) to different temperatures can affect how the body uses energy. Objectives: - To test changes in energy metabolism in response to different room temperatures. Eligibility: - Healthy men between 18 and 40 years of age. Design: * The entire study will last for 4 months. It will involve a screening visit and a 4-month inpatient stay at the National Institutes of Health Clinical Center. The inpatient stay will be in a private room at the Metabolic Clinical Research unit. Study participants will be required to stay in the Metabolic Clinical Research unit during the night, but are free to leave during the day. * At the screening visit, participants will have a physical exam and medical history. Blood samples will be collected. A heart function test and diet questionnaire will also be given. * During the first month, the temperature of the private room will be set at to 75.2 degrees F. This will allow the body to become used to the testing environment. * During the second month, the temperature will be set to either a cool (66.2 degrees F) or a warm (80.6 degrees F) temperature. * During the third month, the temperature will return to 75.2 degrees F. * During the fourth month, the temperature will be altered to the opposite temperature to the one set in the second month. * Throughout stay, participants will have daily temperature monitoring and will keep a food diary. Once a week, they will collect all of their urine for 24 hours. Once a month, they will spend 24 hours in a metabolic suite to study their metabolism rate. * Throughout stay, the food will be provided as part of the study. * During the first and third month (75.2 degrees F) the participants will be allowed to leave the Metabolic Clinical Research unit during the weekends, while during the second and forth month (66.2 or 80.6 degrees F), the participants will be allowed to spend one weekend out of the Metabolic Clinical Research unit. * Other tests, such as body scans, fat tissue samples, and imaging studies, will be performed as needed.
White and brown adipocytes differ in their expression of hormones, cytokines, and inflammatory factors, and they modulate different biological functions. While white adipose tissue (WAT) serves as the primary site of energy storage, brown adipose tissue (BAT) instead metabolizes fat to produce heat and regulate body temperature. BAT is likely present in all humans, but the low prevalence of BAT depiction in adults and elderly subjects has hindered longitudinal assessments of the relation between BAT activity and WAT. Under typical imaging conditions, BAT is detected more frequently in children and teenagers than in adults with malignancy. Since most children with cancer have significantly shorter treatment courses and greater survival rates compared to adult patients, the investigators have the ability to examine the relation of repeated measures of body composition and BAT by selecting pediatric patients. In this study, the investigators will longitudinally examine whether BAT activity is related to changes in weight and the amounts of SAT, VAT, and abdominal muscle in children successfully treated for pediatric cancer.
The investigators propose to conduct a cross-sectional study of 60 participants who are 18-30 years of age to undergo research PET/CT. The purpose of this study is to investigate the relationships between Brown Adipose Tissue (BAT), the adiponectin/leptin (A/L) ratio, and components of the metabolic syndrome in young adults.