Active clinical trials for "Insulin Resistance"

Type 2 diabetes is now more frequent in children/adolescents, especially in those from minority populations, including Hispanic Americans (HA). Diabetes and the pre-diabetes state markedly increase the risk of cardiovascular disease. Endothelial dysfunction is seen in the earliest stages of atherogenesis, which ultimately leads to cardiovascular disease. The main aim of this study is to evaluate the endothelial function in HA children/adolescents who are at risk for developing type 2 diabetes (obese children/adolescents from the Hispanic population). The investigators' hypothesis is that endothelial dysfunction is present in this population and that it is associated with metabolic abnormalities linked to the insulin resistance syndrome. The investigators will study 2 groups of 15 individuals each, age 10-18 years. Group 1 will consist of obese (body mass index greater than 85th percentile for age and sex) Hispanic American children/adolescents and group 2 will consist of healthy, non-overweight (body mass index between the 25th and 50 th percentile for age and sex) Hispanic American children/adolescents. The study will be carried out at the Joslin Diabetes Center. During the first day, participants will have a medical history and full physical examination, a standard OGTT and measurement of blood cell count, plasma glucose, insulin, lipids, HbA1c, BUN, creatinine, electrolytes, estradiol, testosterone, free fatty acids, CRP, endothelial markers, urinary microalbumin and hCG, if appropriate. An OGTT will be performed in order to rule out IGT or Diabetes. Estimations of insulin secretion and insulin sensitivity will be assessed using the homeostasis model assessment (HOMA). In the second day, the body composition and the brachial artery vasodilatory response to hyperemia will be assessed. Those found with diabetes will be tested for GAD-65 and IA2. The investigators' hypothesis is that Hispanic American children/adolescents at risk for type 2 diabetes have impaired endothelial function and vascular reactivity that are associated with the degree of insulin resistance and its metabolic abnormalities.

The average American diet consumed by a significant proportion of the adult population, supplies excessive calories and large amounts of saturated fat. Saturated fats can be cleared and used in skeletal muscle, but in obese individuals, biomarkers of saturated fat are found in the blood, along with markers of poor muscle metabolism. Both fats and amino acids are processed by the same metabolic pathways in muscle, and the investigators hypothesize that meals with greater amounts of saturated fat slow muscle metabolism. A better understanding of the interaction of these to metabolites will allow for the development of future medications to treat muscle loss in sick individuals and the elderly.

The aim of this study is to investigate the markers of bone mineral metabolism in an unconfounded group of patients with hypogonadism and to search for a relationship between endothelial dysfunction and insulin resistance.

Obesity has become an epidemic worldwide. Data from our laboratory and others demonstrate that most of the excess morbidity from obesity is related to insulin resistance (IR). While total adiposity correlates with insulin resistance, not all obese individuals are IR. When obese IR individuals lose weight in response to caloric restriction, even moderate loss of body fat results in improved insulin sensitivity (IS). With massive weight loss, either dietary or surgical, even the most IR individuals can completely reverse their insulin resistance. But why is one individual IR at a BMI of 26 and another IS at a BMI of 35? There must be differences in the manner in which adipose cells/tissue respond to caloric excess and weight gain. One potentially unifying hypothesis with regard to obesity-associated insulin resistance is that those individuals who fail to respond to caloric excess/obesity with adequate adipocyte differentiation and expanded subcutaneous fat storage capacity develop increased circulating FFAs, ectopic fat deposition, stress on adipocytes, triggering localized and systemic inflammation and ultimately insulin resistance in skeletal muscle. Clearly, the best way to examine the human response to obesity is to challenge overweight individuals with the need to store excess triglyceride in adipose tissue. Specific aims are: Test the hypothesis that impaired adipogenesis and fat storage capacity are associated with insulin resistance by comparing 1) cell size distribution; 2) gene markers of adipose cell differentiation; 3) differentiation of isolated preadipocytes in IR-prone vs IS individuals subjected to caloric excess. Determine if circulating (daylong FFA, two-stage Insulin Suppression Test) and ectopic fat (MRI liver, CT abdomen) are worsened to a greater degree in IR-prone vs IS individuals subjected to caloric excess. Determine whether differences in inflammation and/or innate or adaptive immune response are associated with insulin resistance by comparing differences in resident dendritic cells, macrophages and their activation profiles, changes in T-cell subpopulations, and other inflammatory mediators in IR-prone vs IS individuals who are subjected to caloric excess via overfeeding. Exploratory: Evaluate IR-prone vs IS individuals for evidence of hypoxia and insufficient angiogenic response in response to caloric excess.

The study aims to determine in obese patients the implication of intramuscular lipid accumulation in relation with insulin resistance and defect in lipid oxidation.

Hypothesis: Oral Supplementation of Vitamin D can Reduce Hypersecretion of Parathyroid Hormone and Insulin Resistance in Obese Chinese Males. Protocol: Weekly oral supplementation of 50,000 IU vitamin D (cholecalciferol) or eight weeks to the obese males compared with the normal-weight males. Index measures were conducted at baseline and endpoint.

The purpose of this study is to investigate the effect of an exercise training intervention on the ability of African American males to use insulin properly. Insulin is a hormone that helps the body use glucose.

There is little known about menopause in African women, whose phenotype differs to Caucasian women, and no data is available on middle-aged black South African men. Accordingly, the study aims to examine the changes in sex hormone levels over the menopausal transition in women, and in men of the same age, and explore the effects on body fat distribution and insulin sensitivity and secretion, dissecting the specific roles of glucocorticoids and inflammatory mediators, in the context of HIV. Research questions and hypotheses: Does the decrease in sex hormones that occur with ageing increase circulating cortisol and/or inflammatory markers, and directly and/or indirectly via increases in central fat mass, decrease insulin sensitivity in middle-aged black South African men and women? Hypothesis: The mechanism underlying the decrease in insulin sensitivity (outcome) associated with the decline in sex hormones (exposure) that occurs with ageing is mediated via an increase in centralization of body fat (mediator), which is due to an increase in inflammation and cortisol production. How does HIV alter the relationship between sex hormones, inflammation and cortisol levels, and subsequently body fat distribution and insulin sensitivity? Hypothesis: HIV infection will exacerbate the effects of the decline in sex hormones with ageing, leading to further increases in inflammation and cortisol production, and a consequent increase in the centralization of body fat and decrease in insulin sensitivity. Does adipose tissue glucocorticoid and inflammatory gene expression differ between pre- and post-menopausal women, with and without HIV, and how do these relate to body fat distribution and insulin sensitivity and secretion? Hypothesis: Adipose tissue estrogen receptor beta (ERβ), 11-beta hydroxysteroid dehydrogenase type 1 (11HSD1) activity and pro-inflammatory markers will be higher in post- compared to pre-menopausal women, which will be exacerbated by HIV infection. This will be associated with down-regulation of subcutaneous adipose tissue (SAT) adipogenic genes, increased visceral adipose tissue (VAT), a decrease in insulin sensitivity and secretion, and consequently an increased risk for type 2 diabetes (T2D).

The aim of the study is to investigate the effects of capsaicin rich foods on resting energy expenditure and substrate oxidation. We plan to recruit 30 healthy lean and overweight individuals age 18-45 (women) and age 18-50 (men) who will undergo two test days in random order. During one day they will receive a breakfast of toast, orange juice and an omelette with 4tsp of cayenne pepper while on the other day they will receive the same breakfast without the cayenne pepper. Metabolic rate and Respiratory quotients is measured for 30 minutes before the meal and for 2 hours after the meal. Capillary glucose levels and heart rate and blood pressure are measured before the meal and every 30 minutes thereafter for 2 hours.

To investigate the role of ATP sensitive K+ potassium channels and the Na+/K+ pump in the development of fatigue in healthy and in insulin resistant subjects.