Active clinical trials for "Insulin Resistance"

Increased accumulation of fat into the muscles is associated with what is called insulin-resistant state, which is a pre-diabetic state. The purpose of this research is to find out how fat circulating in the blood following fat consumption is taken up by the muscles in healthy people as well as people that are insulin-resistant. The investigators are specifically interested in how a hormone called insulin is involved in this process. Findings from this research will contribute to our understanding of why insulin-resistant people have increased accumulation of fat in their muscles, and ultimately help to design appropriate interventions to prevent type 2 Diabetes.

The purpose of this study is to investigate the changes in subcutaneous adipocyte size, number and gene expression after weight loss and to assess whether those changes contribute to decreases in ectopic fat accumulation and insulin resistance in women between ages of 16-32.

Previous studies have demonstrated defects in the trafficking and translocation of GLUT4 glucose transporter in skeletal muscle and adipose tissue to be a major cause of insulin resistance in humans. IRAP (Secreted Insulin Regulated AminoPeptidase) is a protein which collocalizes and is translocated with GLUT4 to the plasma membrane in response to insulin. The extracellular domain of IRAP is cleaved and released in the bloodstream. Therefore, IRAP plasma concentration could be a good marker of insulin sensitivity. In this study the investigators seek to confirm this hypothesis by using the gold standard of insulin sensitivity assessment: the hyperinsulinemic-euglycemic clamp. It is a multicenter descriptive study.

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: 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. 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. 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.

To explore whether obese adolescents with insulin resistance and relative low leptin levels exhibit functional alterations of the neuronal circuits involved in the regulation of energy metabolism and food seeking behaviors. We here propose to test the hypothesis that the reward circuitry is dysregulated in obese adolescents and is related to the degree of insulin resistance and hyperinsulinemia.

The purpose of this study is to investigate whether higher insulin resistance in young women with Polycystic ovary syndrome (PCOS) is associated with reduced cerebral metabolic rate of glucose (CMRglu). Brain volumes using magnetic resonance imaging (MRI) and quantitative cerebral glucose uptake using dynamic positron emission tomography (PET) were obtained.

Magnesium is an essential mineral found in many foods; rich sources include whole grains, green leafy vegetables, coffee, and legumes. Magnesium is a critical cofactor in >300 enzymatic reactions, including those related to energy metabolism. Reduced magnesium intake and serum concentrations have been detected, both cross-sectionally and prospectively,in type 2 diabetes and insulin resistance, hypertension, dyslipidemia, and cardiovascular diseases. Different studies have reported inadequate magnesium intake and low serum magnesium concentrations may correlated also with metabolic syndrome, defined as a cluster of metabolic disorders including obesity, hypertension, dyslipidemia and impaired glucose tolerance or diabetes mellitus. Previous studies on this subject, however, reported contradicting results. Some investigations reported inadequate magnesium intake and low serum magnesium concentrations while others did not. To our knowledge, the epidemiological evidence on the relation between dietary magnesium intake and risk of metabolic syndrome has not yet been summarized.Therefore, the investigators will perform a systematic review and dose-response meta-analysis to assess the association between dietary and circulating magnesium level and risk of metabolic syndrome.

The investigators hypothesize that the improvements in insulin sensitivity, beta (β)-cell function, and inflammation will be greater, and the improvement in sarcopenic obesity will be less, in younger versus older individuals after substantial weight loss induced by sleeve gastrectomy bariatric surgery.

This study will examine the effects of a dietary fiber on insulin sensitivity in overweight and obese women. The fiber will be added to snack foods and women will consume the foods for four weeks. In one four-week period, 15 g of fiber will be added, and 30 g will added in another period. In a third period, no fiber will be added to the snack foods. Insulin senstivity will be measured at the end of each treatment period.

Insulin resistance is one of the main mechanisms involved in metabolic diseases. inflammation has been implicated in its pathogenesis, due to innate immunity activation by free fatty acids, lipopolysaccharides (LPS) and lactate. Free fatty acids, LPS and lactate activate innate immunity in squelettal muscle and adipose tissue via Toll-like receptor 2/4, NFkB, IRF3 (Interferon Responsive Factor 3) and cytokines secretion (TNFa, IFN g, IL1b, IL6), chemokines secretion (MCP1) and leukotrienes (LTB4). Feed back mechanisms involved in TLR signaling pathways as RLI (ribonuclease L inhibitor)/ABCE1, have never been studied in inflammation due to obesity. RLI inhibits an endoribonuclease, RNase L, which has been recently implicated in TLR signaling The purpose of this study is to analyse the role of RLI and RNase L in TLR regulation, and its potential implication in the link between obesity, inflammation and insulin resistance in adipose tissue and squeletal muscle in humans.