Active clinical trials for "Obesity"

The beneficial effects on plasma lipids of Orlistat, a selective gastrointestinal lipase inhibitor, are largely independent of weight loss, and might include differential effects plasma non-esterified fatty acid (NEFA). Apart from their well-known effects on insulin resistance pathogenesis, elevated NEFA levels probably play also the most important role at peripheral levels in the pathogenesis of Growth Hormone (GH) insufficiency in obesity. Aim of this observational, mono-centre, randomized, simple-blind, cross-over study is to verify if the short-term treatment with Orlistat may results in decline in NEFA circulating levels when used in conjunction with low-fat diet and if this effect may restore the endogenous activity of GH/ Insulin-like growth factor (IGF)-1 axis, in the context of GH regulation of lipoprotein metabolism, thus adding a further benefit of Orlistat in obesity cross-linked neuroendocrine and metabolic dearrangement.

Insulin secretion and insulin sensitivity are related with an inverse, hyperbolic function, the so called disposition index, that shows the critical importance of the ß-cell dysfunction for the development of T2DM. A consequence of the hyperbolic relationship is that increased insulin resistance is compensated by up-regulation of insulin secretion, as it happens in obesity. However, when a defective insulin secretion in relation to insulin sensitivity takes place (i.e. reduced disposition index) then impaired glucose tolerance or type 2 diabetes develop. The investigators have recently demonstrated that bilio-pancreatic diversion determines a prompt reversibility of T2DM by normalizing peripheral insulin sensitivity and enhancing ß-cell sensitivity to glucose; these changes occur within few days after surgery, largely before changes in body weight occur. This operation may affect the entero-insular axis function, by diverting nutrients away from the proximal gastro-intestinal tract and by delivering incompletely digested nutrients to the ileum, thus abnormally stimulating the secretion of intestinal incretins. It has been shown that male Wistar rats undergoing three different types of small intestinal surgery, namely ileal transposition (either 10 or 20 cm of lower ileum transposed to mid-duodenum) or 85% jejuno-ileal bypass, showed a sustained post-operative reduction in food intake and a significant change in body weight gain. All experimental groups had a large increase in basal and meal-stimulated enteroglucagon, while the area under the curve of plasma levels of gastrin, gastric inhibitory polypeptide (GIP), insulin and blood glucose were significantly reduced. GIP is produced mainly in the duodenum and jejunum as shown in dogs .The aim of the present study is to investigate the intestinal site of production of incretins in response to intraluminal nutrients stimulation in order to establish the relationship between insulin resistance, insulin hypersecretion and different small intestinal segments in insulin resistance conditions, such as obesity and T2DM. To this purpose a mixed test meal will be infused in the duodenum, proximal jejunum or ileum and glucose uptake and insulin secretion studied, in relation to glucagon and incretin response. Studies are carried out in 20 obese subjects of both sexes, 10 of whom with type 2 diabetes and 10 with normal glucose tolerance.

The purpose of this research is to further study the effect weight loss after gastric bypass surgery has on the heart and blood pressure and on how the body uses or metabolizes the sugars, fats and proteins we eat. Additionally, the researchers want to study fat tissue for gene patterns which may be responsible for where we carry fat on our bodies, as well as look carefully at a possible link between adipose tissue and insulin resistance. The researchers also want to evaluate the liver for the presence of fatty liver, which is common in people with obesity and is associated with insulin resistance, as well as study the liver for gene patterns which may be associated with non-alcoholic liver disease. Evaluating cardiovascular function and endocrine function before and after gastric bypass surgery, as well as studying adipose and liver tissue may help us understand the link between obesity, insulin resistance, fatty liver disease, high blood pressure and health problems such as diabetes and heart disease. Consequently, this may help in the future by identifying those who will benefit most from gastric bypass surgery.

The importance of exercise for weight control is well documented; however if exercise results in an increase in food intake, the beneficial effect of exercise may not be seen. This study addresses a gap in the current literature and examines why some people eat more after exercise and why some people eat less and also examines whether these responses are consistent over time. Participants in this study will be asked to come to our center on 7 different occasions over a 3-4 month period. The first visit will be an assessment visit where body weight and body composition will be measured, questionnaires will be completed, and an exercise test will be performed. During the remaining 6 visits (3 pairs of sessions with visits in each pair separated by 48-96 hours) the procedures will be nearly identical. Upon arrival at our center, participants will consume a meal replacement, complete a series of questionnaires and then either rest or walk on a treadmill for 30 minutes (3 days will be resting and 3 will be exercising). One hour following the exercise/resting session, individuals will be given access to a buffet of food, unaware that their food intake will be monitored. All food will be weighed and measured before and after the eating period and the amount of food consumed after each pair of exercise and resting conditions will be compared to one another. It is hypothesized that the difference in food intake will be consistent across pairs of testing sessions. Findings from this study will help us to better understand the relationship between exercise and food intake and may ultimately lead to future studies that can address the clinically significant question of why some individuals gain weight and others lose weight when engaging in exercise training programs. Findings from this study may also help to develop exercise programs that maximize the beneficial effect of exercise on body weight.

In 1995 we conducted a cross-sectional study to identify the effects of traditional and western environments on prevalence of type 2 diabetes mellitus (T2DM) and obesity in Pima Indians in Mexico and the United States. The Mexican Pimas live in a remote mountainous region and at that time had experienced little change from their traditional lifestyle. Nothing was known about their T2DM prevalence. A similar number of non-Pima Mexicans live in the same village. In contrast to the Mexican Pimas, the U.S. Pimas live in more westernized society and have a high prevalence of diabetes. We found that although T2DM and obesity were more prevalent in Mexican Pimas than non-Pimas, both Mexican groups had a significantly lower prevalence of these disorders than U.S. Pimas. The lifestyle of the Mexican population studied included a dramatically higher level of physical activity and a diet higher in fiber and lower in calories derived from fat compared with the U.S. Pimas. Since the U.S. and Mexican Pimas share a similar gene pool we concluded that even in populations genetically prone to T2DM and obesity, their development is determined largely by environmental circumstances. Since 1995 the environmental circumstances of the Mexican Pimas and non-Pimas have changed. The electrical supply to the region has increased, cars have become more prevalent and grocery stores have appeared. The impact of these changes on T2DM and obesity has not been examined. In light of these events, we propose to: 1) compare the current prevalence of T2DM and obesity in Mexican Pimas and non-Pima Mexicans to that present in 1995 with the same measures used previously, including height, weight, waist circumference, body composition by bioelectrical impedance, oral glucose tolerance and HbA1c; 2) compare current diet, physical activity and total energy expenditure in both Mexican Pimas and. non-Pima Mexicans using the same methods as the 1995 study to the previous results and 3) document the frequencies of T2DM and obesity-associated genetic variants in Mexican Pimas compared with U.S. Pimas and non-Pima Mexicans.

The purpose of this study is to determine the effect of gastric banding or gastric bypass on hypothalamic morphology and function, gut hormones and systems biology in obese subjects with and without type 2 diabetes.

This study focuses on the difficulties to maintain a weight loss and behavioural change after having been in a institutional intermittent weight loss programme. We explore if including a member of the family or a close friend in the treatment influences weight loss maintenance after completion of the programme.

This is a retrospective longitudinal study that evaluates the prevalence and incidence of overweight/obesity within an HIV-infected population before and after 12 and 24 months of a stable antiretroviral therapy (ART). The study group will be compared to the weight of a healthy, matched population that is not infected with HIV. The primary hypothesis states that the proportion of HIV-infected persons newly classified as overweight/obese will increase by ≥20% after 12 months of initial ART, and this incidence will be greater than that of a matched HIV-uninfected control population. The effect of immune function variables, such as CD4, HIV viral load, and ART regimen on weight will be analyzed. In addition, the study will analyze the effect of weight and immune function markers on the inflammatory markers, high sensitivity C-reactive protein (hsCRP) and D-dimer. An HIV samples repository will be used for specimens to be assayed for hsCRP and D-dimer.

The sole purpose of this study is to evaluate pathophysiology of disease. The disease state that is being evaluated is the obesity-related alterations in reproductive hormones The obesity epidemic in the United States is advancing at an accelerated pace. It is estimated that by 2015, 41% of U.S. adults will be obese as defined by a body mass index (BMI) of greater than 30 kg/m2. The U.S. government's 2010 Dietary Guidelines regard obesity as the single greatest health hazard in this century. Female adult obesity is associated with menstrual cycle irregularities, ovulatory dysfunction and a higher risk of obstetrical complications. This reproductive phenotype of obesity is worsened by further increases in BMI and is not solely due to anovulatory infertility. While the association of adiposity with subfertility is well documented in population studies, the underlying mechanisms remain poorly understood. The main objective of this proposal is to clarify the nature of the obesity-related reproductive endocrine abnormalities and identify potential etiologies amenable to therapy. Hypothesis: The hypothalamic-pituitary axis is abnormally sensitive to estradiol negative feedback in obesity.

The purpose of this study is to quantify the relative contribution of improved insulin sensitivity and improved insulin secretion to the glycaemic effect of bariatric surgery.