Active clinical trials for "Insulin Resistance"

Free fatty acids (FFA) are the main fuel source in a healthy adult heart, since they are responsible for 70-80% of the myocardial ATP production. Plasma FFA and triglycerides (TG) levels are elevated in obesity and diabetes, evoking substrate competition in the heart: the increased availability of lipids will lead to fat accumulation in the heart, which is associated with cardiac insulin resistance and will therefore restrain insulin-stimulated cardiac glucose oxidation. It is shown that a lower myocardial glucose uptake correlates with decreased diastolic function. The benefits of counterbalancing this lipid overload is proven by previous research in pre-diabetes, which showed the reversibility of impaired myocardial substrate metabolism and improvement of function and structure after modest weight loss induced by lifestyle changes. Ciprofibrates are a ligand of the peroxisome proliferator-activated receptor (PPAR) α and are considered to be a major regulator of the lipid metabolism and promote fat oxidative capacity. They are not only effective in normalizing lipid-lipoprotein levels in patients with the metabolic syndrome, but improve also their insulin sensitivity. We therefore hypothesize that ciprofibrate administration in subjects with impaired glucose metabolism (IGM) influence the myocardial substrate metabolism (via the PPARα pathway) and thereby improve myocardial insulin sensivity.

Recent epidemiological studies show that egg consumption is associated with insulin resistance and altered glycemic control. For this study, the investigators hypothesize that this association is due to dietary patterns associated with egg consumption, such as saturated fat, and not the consumption of eggs per se. This study will be conducted in two parts that will be conducted simultaneously. Part I will utilize an ecological momentary assessment approach in which dietary patterns associated with egg intake will be determined using an objective measurement of food intake called remote food photography method. In Part II, a randomized partial crossover study will be conducted on the same sample of subjects to test the effects of egg consumption, saturated fat consumption, and consumption of the combination of eggs and saturated fat on glucose, insulin, and hunger and satiety hormone levels.

This study determined the effect of 7 days of high-fat overfeeding on whole-body glycaemic control, glucose kinetics, skeletal muscle insulin signalling, and markers of skeletal muscle microvascular function in 15 healthy young individuals.

Low birth weight (LBW), a marker of impaired fetal growth is an independent and strong risk factor for type 2 diabetes (T2D). A western lifestyle characterized by a surplus of calories, and/or a low physical activity level, associated with increased fat storage and altered lipid metabolism plays a central role in the pathogenesis of insulin resistance and T2D. Using state-of-the-art large-scale integrative physiology studies combined with basic studies of adipose and muscle tissue stem cell functions, the investigators aim to determine if LBW individuals exhibit decreased subcutaneous adipose tissue expandability, postprandial hyperlipidaemia and ectopic fat accumulation when exposed to 4 weeks of carbohydrate overfeeding. The investigators will subsequently examine if exercise training can revert and/or minimize the deleterious effects of carbohydrate overfeeding in a possibly birth weight differential manner.

Disturbances of de novo lipogenesis (DNL) are one of the features of dysfunction of adipose tissue (AT). Disturbances of DNL play a role in development of metabolic complications of obesity. The goal of this project is to investigate novel pathways of DNL regulation. DNL will be studied during nutritional interventions in healthy and obese subjects in exposure to 2-days high carbohydrate diet preceded by a) 2-days fasting b) several weeks´ ketogenic diet. This nutritional protocol creates conditions for the study of prominent changes in DNL: suppression of DNL during fasting or ketogenic diet followed by stimulation during high-carbohydrate diet. Systemic phenotypic features and molecular indices of DNL regulation in AT will be followed during the protocols. Specific attention will be paid to newly reported pathway- hormone sensitive lipase and transcription factor ChREBP. The results will contribute to development of pharmacological approaches in the treatment of metabolic complications of obesity, targeted selectively to AT, without side effects in other tissues.

Obesity and especially type 2 diabetes (T2D) increases the risk of neurocognitive dysfunctions including adverse effects on brain structure and function. Recent evidence from clinical studies have shown that T2D almost doubles the risk for dementia. As the population gets older, age-related chronic diseases, as T2D, become more prevalent. Scientific evidence is emerging that there are several links between metabolic and neurocognitive functions. Impaired insulin action (i.e. insulin resistance), the main hallmark of T2D, has been suggested as a likely shared common pathophysiological mechanism. However, the neural processes that determine how insulin resistance is are connected to the onset and progression of T2D and dementia remain unclear. In this context, the overall aim is to study brain insulin resistance to disentangle age-related and obesity related brain insulin resistance in healthy normal and overweight/obese persons at the age of 20 to 70 years . To this end, the investigators will assess brain insulin action using intranasal insulin/placebo during functional Magnetic Resonance Imaging (fMRI). Additionally, structural changes and cognitive processes will be assessed as secondary variables.

The aim of the current study is to investigate the ability of antioxidants found in cocoa ('flavanols') to increase the body's sensitivity to the hormone insulin. 32 overweight or mildly obese women, who are otherwise healthy, will be recruited. Subjects will attend the laboratory on 3 occasions after fasting from midnight. The 1st visit is a medical screening, with laboratory visits 2 and 3 separated by 4 weeks, during which time subjects will consume a cocoa drink (containing either high or low amounts of flavanols) twice a day. Subjects will record their food intake for 3-days before visit 2 and in week 3 of consuming the cocoa. They will also eat a diet of standard macronutrient composition for 3 days before visits 2 and 3. During the 5 hour laboratory visits, subjects will have a scan to assess their body composition using a low-dose x-ray machine (Dual Energy X-ray Absorptiometry; DEXA), and have their insulin sensitivity measured using a 3 hour hyperinsulinemic, euglycaemic Clamp.

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.

Healthy subjects with low Vitamin D levels will be randomly assigned to either Vitamin D replacement or placebo for a period of 8 weeks. Insulin sensitivity will be measured before and after the intervention, and the changes will be compared between the two groups. This will help us understand if Vitamin D replacement improves insulin sensitivity. Serum Retinol Binding Protein 4 levels will also be measured to see if changes in insulin sensitivity are mediated by RBP4.

Obesity has a greater detrimental impact on the health of African American women than on any other racial or gender group. Nearly 80% of African American women are overweight or obese in the United States. Hypertension and insulin resistance are more prevalent among African American women as compared to men and Caucasians. These conditions put them at increased risk for the development of diabetes mellitus and cardiovascular disease. Recent studies have reported that a substance named Nitric Oxide (NO)may have some beneficial effect on how the body handles blood sugar and blood pressure. Of interest,some studies have shown that African Americans have decreased function of NO in their blood vessels. In this study proposal the investigators will test if increasing NO function with a PDE-5 inhibitor (sildenafil citrate) will improve pre-diabetes and the health of the inner layer of the blood vessels in obese African American women.