22 Clinical Trials for Various Conditions
Obesity is a direct result of food-intake in excess of body energy expenditure. Thus, induction of increased energy expenditure via the activation of thermogenesis at targeted anatomical sites can counterbalance obesity. This trial aims to study RZL-012, a novel compound, in treating obesity by activating thermogenesis in subcutaneous fat.
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).
Non-exercise activity thermogenesis (NEAT) is the energy expended engaging in daily activities such as maintenance of posture, fidgeting, and other activities not specifically designated as "exercise." A growing body of evidence indicates that NEAT plays an important role in overall energy balance; for example, differences in NEAT account for the ease with which adults gain or lose weight during over- or under feeding. An intriguing and possibly modifiable component of NEAT is fidgeting-like activity. In lean and overweight adults, modulation of NEAT by augmenting fidgeting can increase short-term energy expenditure. It is unknown whether NEAT can be altered in children, or whether augmenting NEAT in children can change daily energy expenditure or body composition long-term. Children exhibit higher levels of daily activity than adults, suggesting potentially profound differences in energy balance. We propose to study the role of NEAT in children to determine if: a) the fidgeting component of NEAT can be measured accurately and reproducibly in children; b) NEAT can be increased by devices that remind children to engage in fidgeting-like activities; and c) manipulation of fidgeting-NEAT can significantly change energy expenditure and body composition. Thirty lean and thirty overweight children will be enrolled and treated in a pilot feasibility study. By adapting technologies developed to measure activity in adults, children's behavior and thermogenesis will be recorded and analyzed to study question (a). To address study questions (b) and (c), we will ask children to wear a timer that vibrate on a fixed interval schedule and be randomly assigned to two conditions: the intervention or active condition, during which children will be cued by the timer to engage in a fidgeting behavior (rapidly moving their heel up and down), and the control condition, during which children will be asked to perform a less thermogenic activity (noting the cue). Children will then cross over so that each child will complete both conditions. Primary outcome measures for question (a) will be changes in energy expenditure when subjects are asked to fidget in a laboratory environment. The correlation of these energy expenditure measurements with new activity monitoring technologies will also be obtained, so that such equipment can be used for measurements under free-living conditions. For study questions (b) and (c), compliance with prescribed fidgeting regimens in a free living environment and the changes in energy expenditure and body composition will be determined over a 2 week interval. This pilot study will enable the determination of the sample size needed to assess the efficacy of a longer term NEAT intervention in children.
Background: Diet-induced thermogenesis (DIT) is the amount of energy one s body uses to eat food, absorb the nutrients from the food, and process those nutrients. Researchers would like to understand more about how changing the balances of protein, fat, carbohydrates, and total calories in the diet can affect DIT. Objective: To learn how different diets can change a person s DIT. Eligibility: Healthy people aged 18 to 60 years who have not intentionally lost weight in the past 6 months. Design: Participants will stay in a clinic for about 35 days. They will eat only the food provided. They will receive 8 different diets during the study, including 7 test diets. Participants will undergo multiple tests. They will be screened with blood and urine tests and a test of their heart function. During the first few days: Their waist, thigh, and neck circumference will be measured. They will have a DXA scan: They will lie on a padded table for about 20 minutes while an instrument measures the amount of fat in their body. They will be tested for diabetes. They will answer questionnaires about topics including eating behavior, hunger, and stress. Throughout the study: Their weight will be measured daily. Blood tests will be repeated. They will stay in a metabolic chamber a total of 9 times. They will remain in a closed room for 24 hours while researchers monitor the room temperature and levels of oxygen and carbon dioxide. Participants will collect all their urine for each 24-hour period. ...
Background: - Changes in how a person's body burns energy or calories can affect their weight over time. The lowest level of energy the body needs to function is called basal metabolic rate. In the cold, we burn extra energy, even before we start to shiver. This is called non-shivering thermogenesis and it occurs in different types of tissue such as muscle and fat. Researchers want to learn more about this type of energy burning and how it is regulated. They hope this will help treat obesity in the future. Objectives: * Sub-study 1: to better understand how non-shivering thermogenesis works. * Sub-study 2: to measure the effects of anti-obesity drugs on basal metabolic rate. * Sub-study 3: to better understand the effects of mirabegron, a beta-3 adrenergic receptor agonist, on brown fat activity. Eligibility: - Healthy, lean adult males ages 18 to 35. Design: * Participants will be screened with medical history, physical exam, blood test, and EKG. * For sub-studies 1 and 2: * Participants will receive one X-ray scan. * Each day, all participants will: * Have height and weight measured, and have urine collected. * Spend 4 hours in a temperature-controlled room with furniture, toilet area, phone, and computer. They will wear small non-invasive devices to monitor activity, heart rate, temperature, and shivering. * Walk for 30 minutes. * For sub-study 3: * Participants will receive one DXA scan and up to 4 PET/CT scans and 4 MRIs * Each stay, all participants will: * Have height and weight measured, and have urine collected. * Spend 6 hours in a temperature-controlled room with furniture, toilet area, phone, and computer. They will wear small non-invasive devices to monitor activity, heart rate, temperature, and shivering. * Participants will be compensated for their time and participation at the end of the study
The study is considered research because efficacy (how well a drug works) information is needed in healthy, 25-45 year-old, female subjects with moderate caffeine intake. The investigational product is available in the United States without a prescription (over-the-counter) as a nutritional supplement. The purpose of this study is to assess whether One-A-Day Weightsmart Advanced is safe and can increase metabolism and perceived energy in female subjects compared with caffeine or placebo (inactive drug). Participation in this study will last approximately 4 weeks and require about 4 outpatient visits to St. Luk's-Roosevelt Hospital Center. About 21 subjects are expected to participate in this study.
These studies will provide us with enormous insight regarding how obese patients adapt energetically during negative energy balance. We will gain fundamental information regarding the metabolic implications of combining food restriction with a walking program compatible to that advocated by statutory agencies. These studies will lead to improved understanding of the energetic adaptation that occurs during negative energy balance and how best to treat patients with obesity.
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.
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.
The long term goal is to identify the potential therapeutic targets for the treatment of obesity and its associated disorders by studying the driving factors of activation of brown adipose tissue (BAT) in human adults. Whereas activation of brown adipose tissue (BAT) in human adults has been considered as a potential therapeutic target to battle obesity since it was identified in 2009, the underlying mechanisms of beige adipocytes appearance in human adults is unclear. The objective of this proposal is to investigate the role of autophagy in mediating the inhibitory effect of mammalian target of rapamycin complex 1 (mTORC1) in regulating human brown adipocytes. The central hypothesis is that autophagy plays a critical role in regulating browning of white adipose tissue and mediates the beneficial effect of mTORC1 inhibition on thermogenesis in human brown adipocytes.
The investigators aim to establish a protocol for metabolic rate measurements obtained using continuous monitoring of oxygen consumption and carbon dioxide production in a whole room calorimeter setting.
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.
The purpose of this study is to assess the effect of Metabolism-boosting Beverages (MBB) containing green tea extract with a standardized amount of epigallocatechin gallate (EGCG) and caffeine.
A 4 week intake of drug to find a natural substance that may modify energy balance and may enhance health in combination with lifestyle changes with possible decrease in body weight.
This study will investigate how different parts of the body lose body heat and will measure the heat released by specific areas such as the limbs and abdomen. Animal studies suggest that dissipation of body heat may affect energy expenditure, and therefore, body weight. This study will explore the relationship between obesity and heat in humans. Healthy people 18 years of age and older who are of normal weight or who are obese and who are not taking medications for obesity-related medical conditions may be eligible for this study. Candidates must have a body mass index (BMI) between 18 and 25 kg/m2 for normal weight subjects or a BMI greater than 30 kg/m2 for obese subjects. All candidates must weigh less than 300 pounds. Women must have a normal menstrual cycle or be postmenopausal. Participants undergo the following procedures in a single day on an outpatient basis: * Medical history, physical examination, blood and urine tests and electrocardiogram. * DEXA and MRI scans of the trunk and limbs to measure the amounts of muscle, bone and fat in the body. For the DEXA scan, the subject lies on a table while a very small dose of x-rays is passed through the body. For the MRI, the subject lies on a table that is moved into a steel cylinder. A magnetic field and radio waves produce images that are used to measure fat in the trunk of the body, thighs, and arms. * Infrared photography of hands, front of thigh, and abdomen. A special camera is used to measure the heat leaving the body. * Bicycle exercise test. The subject exercises on a stationary bicycle while the heart rate, heart rhythm, blood pressure and oxygen consumption are measured. The pedal resistance is increased gradually until the subject can no longer exercise and then the resistance is gradually decreased for cool-down. Participants who qualify for the second part of the study undergo the following procedures during a 5-day in-hospital stay: * Temperature measurements. Body temperature is measured in the ear canal. Skin temperature is measured with small round adhesive temperature-sensing patches placed on the abdomen and limbs for up to 5 days. * Measurement of body radiowaves. A remote sensing device is used to measure microwaves that are naturally released from the body. * Infrared photography of hands, front of thigh and abdomen is done several times during the study. * Application of mild coolness to hands, thigh and abdomen. The subject's hand is exposed to mild coolness first by immersion in cool water, then by a cool-water spray, then by a cooled pad placed on the hand, and finally, with a device applied to the hand that cools and has a gentle vacuum. The abdomen and thigh are similarly exposed. During each test, an infrared camera records how heat is released by the body. * Temperature effects of a "meal." The subject drinks lemon-flavored sugar water to measure the body's response. * Bicycle exercise test. The subject exercises on three different occasions. During or after some of the tests, mild cooling is applied to the abdomen, front of the thigh, or hands. * Measurement of exhaled air (indirect calorimetry). The subject wears a hood that collects and analyzes exhaled air for 15- to 30-minute periods. * Photography and videotaping. The subject is photographed and videotaped. The images do not include views of any private parts, and the subject's identity is protected.
This study plans to learn more about why menopause increases the risk of weight gain. During and after menopause, women are prone to increased weight gain. The weight gained is primarily body fat, particularly visceral or abdominal body fat. The excess gain in abdominal fat during menopause increases the risk of chronic metabolic diseases such as heart disease and diabetes. The increase in weight and body fat with menopause may be due to changes in metabolism related to the loss of estrogen. This study plans to compare how the metabolism of premenopausal and postmenopausal women responds to changes in energy intake. The investigators will compare the changes in energy expenditure that occur during a period of acute fasting (24 hours) and a period of consuming excess calories (overfeeding).
The goal of this clinical trial is to test whether food timing impacts metabolic health in healthy participants. Participants will: * complete 2 inpatient stays * be provided with test meals * have frequent blood draws
Obesity is reaching epidemic proportions and threatens both health and quality of life of people around the world. While many individuals succeed at short term weight loss, weight loss maintenance is the greatest barrier to successful treatment of obesity. High levels of physical activity are consistently associated with success in weight loss maintenance. The major goal of this proposal is to understand how and why high levels of physical activity are critical for long term maintenance of weight loss. This project takes advantage of the National Weight Control Registry (NWCR), which follows over 6000 individuals who have maintained a weight loss of ≥30 pounds for ≥1 year. Understanding how individuals successful at weight loss maintenance achieve energy balance will provide important insight into strategies to help more people sustain a weight loss.
The purpose of the current study was to examine the impact of macronutrient intake (PRO, 15% vs. 35%) and meal frequency (3 vs. 6 meals/day) on body composition, postprandial thermogenesis and plasma adipokines before and after 28days each of EB (28days) and ED (25%; 28days) in overweight individuals. We hypothesize that HP will elicit more favorable body composition, thermogenic, and cardiometabolic changes than HC intakes and the magnitude of change will be greatest in those consuming HP meals more frequently.
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.
This study, conducted at the NIH Clinical Research Unit at the Phoenix Indian Medical Center, will examine how the body s metabolism (energy expenditure) changes when people overeat and when they fast and how different diets (e.g., high-protein or high-fat) affect metabolism. The results may provide information about whether there are mechanisms that make some people more resistant than others to gaining weight when they eat more. Non-smoking healthy subjects between 18 and 55 years of age who weigh no more than 350 pounds may be eligible for this study. Participants undergo the following procedures: * Pregnancy test for women of childbearing age. * Oral glucose tolerance test. For this test, an I.V. line (needle attached to a plastic tube) is inserted into a vein to allow several blood draws without repeated needle sticks. After the first blood sample is drawn, the subject drinks a cola-flavored sugar solution. Five additional blood samples are then drawn over 3 hours. * Blood test for DNA (genetic) studies related to obesity, diabetes and related medical problems. * DEXA scan. This test measures body fat. The subject lies on a table while a very small dose of X-rays is passed through the body. * Respiratory chamber. This test measures how many calories the body burns a day and assesses energy balance between intake and expenditure. Subjects stay in a room with two windows, equipped with a sink, toilet, television and DVD player, desk, chair, telephone and bed for 24 hours. The test is repeated five times during the first 18-day admission and 3 times during the second 13-day admission. For the first two sessions, subjects are fed a diet equal to the amount of energy their body uses. For the next 6 stays they are fed double the amount of calories their body usually uses for 5 of the stays and fast (consume nothing but water and soda without caffeine or calories) during 1 stay. The overfeeding diets may be high or low in protein, normal in protein, or high in fat. Blood tests are done on the day of each respiratory chamber session and a 24-hour urine sample is collected for one day while in the chamber. * Eating behavior questionnaires. * Psychological performance tests. Some participants are asked to volunteer to repeat two of the chamber studies to validate the measurements. The repeat session includes only the fasting and the overfeeding with normal protein content. All participants are followed at 6 months with blood tests, a DEXA scan, and urine tests (including pregnancy test for women). At annual visits for years 1 through 7, participants have the 6-month tests plus an oral glucose tolerance test.