Active clinical trials for "Insulin Resistance"

The purpose of this study is to learn more about what causes insulin resistance. It has been suggested that proper breakdown of fat into energy (oxidation) in the body is important to allow insulin to keep blood sugar in the normal range. The investigators want to know if having one of the fatty acid oxidation disorders could have an influence on insulin action. Fatty acid oxidation disorders are genetic disorders that inhibit one of the enzymes that converts fat into energy. The investigators will study both normal healthy people and people with a long-chain fatty acid oxidation disorder.

The investigators hypothesized that there will be a significant difference between the effects of trans-free palm-, interesterified palm- and interesterified soybean oil blend on cardiovascular disease, inflammation, insulin resistance and obesity.

Trans-palmitoleic acid (trans-C16:1) is a naturally occurring trans fatty acid present in small quantities in foods, most notably in dairy products. Observational evidence suggests a positive association between trans-C16:1 and insulin sensitivity, and negative association with risk of developing type 2 diabetes mellitus [1-3]. Cis-palmitoleic acid (cis-C16:1) is found naturally in foods and is particularly high in macadamia nuts and oil extracted from the sea buckthorn plant. Animal models suggest that this palmitoleic acid isomer also improves insulin sensitivity and reduces metabolic dysfunction. This pilot dosing study is necessary to inform the design of a larger trial to test the hypothesis that both trans-C16:1 and cis-C16:1 improve insulin resistance but at different doses. Plasma phospholipid fatty acid profiles will be used as the primary outcome measure.

The adipose (fat) cells under the skin are where individuals store excess fat. The more excess fat they have, the more "strain" they put on these cells which then get bigger and don't work as well as they should. Having some fat under the skin is important. People who have a genetic defect which results in them having almost no fat under their skin have a very high risk of a condition called insulin resistance (where the body does not respond as well to insulin and blood sugar levels rise). This can lead to diabetes and heart disease despite them not being overweight. Scientists have only recently started to understand the importance of fat in insulin resistance and how people unable to store fat very well can have insulin resistance despite not being obese. The investigators have also recently discovered that small changes in a person's genetic code (their body's instruction manual) may also affect their ability to store fat and would like to explore this in more detail. To do this, they will recruit volunteers from the Exeter 10,000 study who gave permission to contact them about further research. The investigators will collect detailed body size measures and blood samples taken before and after a special drink that is high in fat (similar to a thick milk shake), then compare the results between people with and without the particular genetic changes of interest. Knowing more about these genetic changes and how fat cells work could help to improve understanding about why some people develop diabetes and heart disease despite a relatively normal BMI.

In this study the investigators will examine the effect of dopamine (bromocriptine) on insulin sensitivity in lean and obese subjects. Furthermore, the investigators will examine whether the timing of bromocriptine administration has influence on insulin sensitivity. To do so, the investigators will include lean and obese subjects who will use 2 times 2 weeks bromocriptine. In randomized order, they will use it in the morning or in the evening. The investigators will examine insulin sensitivity by performing a 7-point oral glucose tolerance test. Furthermore, the investigators will examine energy expenditure and subjects will keep track of their eating behaviour in the 3 days before each study visit.

Branched-chain amino acids (BCAA) belong among nutrients strongly linked with insulin sensitivity (IS) measures. Their exact effect on IS appears to be dependent on various conditions that remain to be better defined . The aim of the current study was to investigate effects of chronic increase of BCAA intake on IS in two groups of healthy subjects differing in their basal consumption of BCAA, i.e. vegans and omnivores. Interventional trial was designed where vegans and omnivores were separately interveined with 15 (women) or 20 (men) grams of BCAA daily. Examinations of participants are intended to be done at baseline, after the intervention and wash-out period. Examinations (anthropometry, hyperinsulinaemic-euglycaemic clamp, arginine test) and blood analyses will be performed at baseline, after the intervention and after a 6 month wash-out period. Samples of subcutaneous abdominal adipose tissue (AT) and skeletal muscle (SM, vastus lateralis) obtained before and after the intervention will be used for various analyses (mRNA levels of selected metabolic markers, fatty acid composition, mitochondrial activity).

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.

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.