Active clinical trials for "Insulin Resistance"

The purpose of this study is to determine the dose-dependent impact of 6 month freeze-dried blueberry powder intake on insulin sensitivity and resistance, cardiovascular disease risk factors, and lung and cognitive function in overweight and obese participants with metabolic syndrome. We will also examine acute post-prandial effects of blueberry intake (at baseline and at 6-months).

Insulin resistance, a primary component of the metabolic syndrome, is an escalating phenomenon in the United States, and confers an increased risk of depression and mood disorder, particularly in women. The relationship between metabolic and mood disorders may be mediated by endogenous opioid activity in limbic brain regions. We propose to examine affective state and μ- opioid system function in insulin resistant women, and change in response to insulin sensitizing treatment, through the following specific aims and hypotheses: Establish relationship between insulin resistance, affective state, and μ-opioid receptor function. Insulin resistant women will have greater μ-opioid receptor availability at baseline, and a larger response to stress challenge than non-insulin resistant women Insulin resistant women will have greater negative affective state at baseline, and a greater emotional response to stress challenge than non-insulin resistant women. Mediational analyses will reveal that the relationship between insulin resistance and negative affect is mediated by μ-opioid receptor function and neural activation in the amygdala and nucleus accumbens affect-regulating regions. Examine effects of insulin regulation on μ-opioid receptor function and affective state. Improved insulin sensitivity will be accompanied by decreased μ-opioid receptor availability at baseline and a reduced response to stress challenge. Degree of change in baseline receptor availability and response to stress challenge after treatment will correlate with degree of insulin regulation. Improved insulin sensitivity will be associated with improved affective state at baseline, and with a reduced emotional response to stress challenge. Degree of change in affective state and emotional response to stress challenge after treatment will correlate with degree of insulin regulation. Mediational analyses will reveal that the change in affective state after insulin regulation is mediated by change in μ-opioid receptor function and neural activation in the amygdala and nucleus accumbens. The expected results would suggest a role for the endogenous μ-opioid system in mediating the relationship between metabolic function and emotional processes.

Diacylglycerol oil has been shown to lower postprandial and fasting serum triacylglycerol levels and reduce body fat. The investigators hypothesize that replacing dietary fat with diacylglycerol oil reduces excess body fat in type 2 diabetic patients and that diacylglycerol oil has a beneficial effect on cardiovascular risk factors in Chinese type 2 diabetic patients.

Weight gain is a common complication after transplantation. It has adverse effects such as hypertension, dyslipidemia, and insulin resistance. Weight gain is implicated in the increased cardiovascular risk and the long-term loss of graft function. Weight loss achieved by a suitable dietary intervention in these patients transplanted kidney can correct lipid disorders and facilitate balance blood pressure. The identification of mechanisms responsible for weight gain would suggest prevention strategies and allow to align the caloric energy needs of renal transplant patients.

Recent findings document the presence of active brown adipose tissue (BAT) in humans. Cold exposure via adrenergic stimulation activates BAT, which combusts significant amounts of blood glucose and free fatty acid (FFA) to produce heat. Animal studies suggest that BAT activation improves insulin sensitivity. However, the effect of cold-induced BAT activation on insulin sensitivity and glucose kinetics in humans remains unknown. The investigators' central hypothesis is that cold-induced BAT activation increases whole body insulin sensitivity in humans via augmented plasma glucose and FFA clearance. The specific aims of this study are to define the effects of prolonged (8h) cold exposure BAT activation on: insulin sensitivity (Aim 1); lipolysis and plasma glucose and FFA kinetics (Aim 2); on thermoregulation (Aim 3). Moreover, the investigators plan to investigate for alternative ways, which can activate BAT including cold water ingestion, a single meal ingestion, and a single bout of moderate intensity exercise (Aim 4). For the cold exposure study, subjects will complete 3 trials: a) 8hrs of cold exposure at their individually determined shivering threshold; b) 8hrs of cold exposure at their individually determined shivering threshold plus propranolol; c) 8hrs in thermoneutral conditions (26 - 28°C). For the rest of the arms of subjects will complete two trials: cold or tepid water ingestion, a single meal ingestion or no food ingestion, and a single bout of moderate intensity exercise or no exercise.To study the above aims, the investigators will use positron emission tomography - computed tomography, hyperinsulinemic euglycemic clamp, infusion of stable isotopes, and tissue biopsies. The findings will illuminate the role of BAT on plasma substrate regulation and insulin sensitivity and may aid in the development of lifestyle recommendations and pharmacotherapy for the prevention and treatment of diabetes and insulin resistance.

The effects of physical inactivity on variations in blood glucose and vascular health are not fully understood. The purpose of this study is to determine if an acute transition from physical activity to inactivity alters vascular health. Specifically, the investigators wish to examine in healthy, lean physically active individuals (obtaining greater than 10,000 steps/day) if decreasing physical activity (obtaining less than 5,000 steps/day) will alter blood flow following a meal a marker of vascular health. Furthermore, the investigators wish to examine if a one day return to physical activity (obtaining >10,000 steps/day) can restore the detrimental effects on blood flow following a meal.

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.

Two important mechanisms play a major role in the pathogenesis of type 2 diabetes: insulin resistance of the target tissues and the impaired insulin secretion from pancreatic β-cells. Postprandial factors (such as insulin) are perceived by the human brain and induce signals that regulate glucose metabolism via the parasympathetic nervous system. Transcutaneous auricular vagus nerve stimulation (tVNS) can be used on the outer ear to stimulate the auricular branch of the vagus nerve in humans. Heart rate variability (HRV) in healthy people can be significantly increased via tVNS, indicating a shift from sympathetic activity to parasympathetic activity. The hypothesis is that this postprandial shift results in a change in peripheral glucose metabolism. In turn, the increased parasympathetic activity could potentially result in a change in postprandial insulin sensitivity or secretion. To test this hypothesis, this study investigates the effect of vagal stimulation versus sham stimulation on insulin sensitivity, on insulin secretion, glucose tolerance, resting energy expenditure, and on parasympathetic tone (analysis of heart rate variability).