View clinical trials related to Insulin Resistance.
Filter by:In this study, the investigators want to examine the impact of coronary artery bypass graft (CABG) surgery on skeletal muscle mass, muscle metabolism, and insulin sensitivity in 90 subjects. In extent, the impact of a subsequent exercise intervention will be examined, with a follow-up up to 12 months after surgery.
The incidence of Non alcoholic fatty liver disease (NAFLD) continues to increase, and prevalence estimates for NAFLD range from 17-33%, making it is the most common cause of chronic liver disease in North America. It is associated with increased cardiovascular morbidity as well as progression to cirrhosis is a subset of patients. There is currently no approved treatment for NAFLD. A key barrier to the development of effective therapies is a lack of consensus on the criteria for diagnosis and endpoints for studies evaluating diagnostic markers, prognosis and therapeutic modalities. NAFLD encompasses an entire pathological spectrum of disease, from relatively benign accumulation of lipid (steatosis) to progressive non alcoholic steatohepatitis (NASH) associated with inflammation, fibrosis, and necrosis. It has been estimated that 20-30% of patients with NAFLD will exhibit biochemical and histological changes characteristic of NASH, and 15-20% of those patients will progress to have cirrhosis. NASH remains an important phenotypic state, because this sub-group of patients is deemed at high-risk for developing progressive disease resulting in cirrhosis, liver failure requiring transplantation, or death. Although NAFLD has not to date been included as a component of the metabolic syndrome, there is increasing evidence that NAFLD frequently accompanies the development of insulin resistance and therefore may be an indicator or predictor of future cardiometabolic risk. Moreover, recent findings in skeletal muscle of experimental insulin resistance (lipid infusion) as well as naturally occurring obese and type 2 diabetic, insulin resistant patients show that skeletal muscle inflammation leads to a pattern of extracellular matrix, structural, and remodeling abnormalities that closely resemble the TGFb, connective tissue growth factor (CTGF) mediated fibrotic response that differentiates simple steatotic liver from NASH. This suggests there may be a common underlying mechanism. Given the ready availability of skeletal muscle tissue using percutaneous needle muscle biopsies, compared to the more invasive liver biopsy, it may be possible to use characteristics of skeletal muscle to distinguish the severity of liver fibrosis. Given the preponderance of patients being identified with NAFLD, the recognition of less and non invasive tests that help to discriminate the different phenotypic types of NAFLD would be highly practical and useful. This would help identify patients at risk of progression to cirrhosis, and thus make them the target of any available therapeutic interventions. The investigators hypothesize that 1. Insulin resistance measured through glucose tolerance test directly correlates with the extent of liver and muscle fibrosis, and 2. Inflammation and fibrosis in the skeletal muscles correlates with the histopathological changes seen in patients with NAFLD, and potentially skeletal muscle inflammation may be used as a diagnostic predictor to differentiate patients with NASH from patients with simple steatosis. The overall goal of this project is to determine the extent to which inflammation and fibrosis in skeletal muscle mirrors and is predictive of the level of liver inflammation and can distinguish NASH from simple steatosis. Specifically, the investigators propose the following Aims: 1. To use estimates of insulin sensitivity from modeling of oral glucose tolerance tests to test the hypothesis that the extent of liver and muscle fibrosis is directly related to insulin resistance. 2. To use liver and muscle biopsies to characterize the changes in abundance of mRNAs and proteins that characterize inflammation, extracellular matrix remodeling, and fibrosis. The investigators will use quantitative rt-PCR and immunoblot analysis to compare mRNA expression and protein abundance of collagens I and III, fibronectin, and connective tissue growth factor (CTGF) to test the hypothesis that there is a direct relationship between the levels of these proteins in muscle and liver and the degree of fibrosis. 3. To establish a biospecimen repository of serum, mRNA from circulating white blood cells, liver and muscle tissue, and DNA to serve as the substrate for future studies of the pathogenesis of NASH.
The optimal dose of vitamin D needed to optimize beneficial effects on musculoskeletal outcomes remains to be defined. Equally unclear is the impact of vitamin D on fuel metabolism and insulin sensitivity in human subjects. Thus, the overall objective of this proposal is to test the hypothesis that in ambulatory overweight elderly individuals, vitamin D administration at doses higher than currently recommended will: 1. Have a salutary effect on parameters of glucose and fuel metabolism. It will thus decrease indices of insulin resistance, improve lipid profile, and decrease markers of cardiovascular disease including adipokines, inflammatory cytokines, and markers of cell adhesion. 2. Have a superior effect on indices of mineral and musculoskeletal metabolism, including bone remodeling markers, lean mass, and bone mineral density. We will investigate whether this effect is modulated by entry status of vitaminD and PTH as detailed below
Studies have shown that people with certain disorders have an increased risk of developing a condition called Metabolic Syndrome (MS). In this study, the investigators want to learn more about MS among people staying in the hospital for treatment of Major Depressive Disorder (MDD) and also Major Depressive Disorder with Psychotic Features (MDpsy). The investigators also want to learn more about a stress hormone called cortisol that is made in the body. Those who take part in this study will answer some questionnaires, be given some psychiatric interviews, and have some blood taken along with a urine sample. The investigators believe that patients in the hospital with MDpsy will have higher baseline rates of MS factors, cortisol levels, dexamethasone non-suppression, and insulin resistance, compared with MDD alone.
This study will evaluate the potential beneficial cardiometabolic effect of moderate (5%) weight loss and progressive (5%, 10%, and 15%) weight loss in obese adults without diabetes. Participants will be randomly assigned to one of 2 groups. Group 1: supervised weight loss group (low-calorie diet). Group 2: supervised weight maintenance group (normal diet). Of those assigned to group 1, half of the participants will lose 5% of their body weight and the other half will lose 5%, 10%, and 15% of their weight over time under the guidance of a dietitian. Research testing will be repeated at each time point (5%, 10%, and 15% weight loss). In group 2, research testing will be repeated after six months.
The effect of Non-Exercise Activity Thermogenesis (NEAT) or inactivity on insulin sensitivity and lipid metabolism is unclear. Research recently published shows that activities associated with everyday activities, summarized as NEAT, such as walking and standing, have a much greater role in energy expenditure than exercise. Therefore, the objective of the present study is to evaluate the effect of 4 days of inactivity (mainly sitting), 4 days of everyday activities (sitting, walking and standing), and 4 days of inactivity and exercise (sitting and biking) on glucose metabolism and insulin sensitivity using an oral glucose tolerance test, and on lipid metabolism in sedentary, overweight people. The investigators hypothesize that: 1. 4 days of everyday activities (NEAT) will cause an increased glucose tolerance and increased insulin sensitivity compared to 4 days of inactivity in sedentary, overweight people. 2. 4 days of exercise will improve glucose tolerance and insulin sensitivity more than 4 days of NEAT with equal energy expenditure, in sedentary, overweight people. 3. Fasting triglyceride will have the same course as glucose, mentioned in 1. and 2.
Obesity and insulin resistance may be in part explained by an altered reward system with changes in the serotonin/dopamine system. These changes might be caused by changes in dietary habits, especially by an increased intake of liquid sugar and an increase in meal frequency. The investigators hypothesize that increasing meal frequency compared to increasing meal size and when consuming a hypercaloric high-sugar diet (HS) compared to a hypercaloric high-fat-high-sugar diet (HFHS) will result in a reduction in cerebral serotonin and dopamine transporters and in a more prominent increase in insulin resistance. In addition, the investigators hypothesize that the changes in insulin sensitivity will be independent of changes in abdominal (visceral) and liver fat and that changes in insulin sensitivity due to the dietary manipulation will co-occur with changes in insulin signaling pathways in peripheral fat and muscle tissue.
Hypomagnesemia is common in renal transplant recipients and is mainly because of enhanced renal magnesium wasting, caused by immunosuppressive drugs (calcineurin inhibitors). Glucose metabolism disorders, including insulin resistance and decreased insulin secretion, are also prevalent post-transplantation and often precede the development of diabetes. As magnesium supplementation has been demonstrated to increase insulin sensitivity in both diabetic and non-diabetic patients, its potential therapeutic supplementation (post-transplantation) deserves further examination. The hypothesis is that magnesium supplementation in renal transplant recipients exerts a beneficial effect on insulin resistance and/or secretion.
The study is designed to investigate the relationship between insulin resistance and non-alcoholic fatty liver disease (NAFLD) and to investigate potential mechanisms underlying insulin resistance in NAFLD by determining associations between hepatic and peripheral insulin sensitivity, hepatic steatosis, dyslipidemia, inflammatory cytokines, glucose metabolism, beta-cell function and body fat distribution.
The purpose of the study is to determine if a low glycemic load diet reduces the gain of body fat and insulin resistance during the last half of pregnancy in obese women.