Diagnosis of Insulin Resistance: 13C-Glucose Breath Test Vs HOMA Index.
Glucose IntoleranceInsulin Resistance2 moreThe prevalence of type 2 diabetes is rising in the population for many years. It is now recognized that a period of glucose intolerance precedes the clinical symptoms appearance. This is due to a combination of b-cell dysfunction and insulin resistance. It is estimated that this pre-clinical phase of type 2diabetes may antedate the onset of overt diabetes by 10-12 years. Furthermore, insulin resistance is considered to be a main component of the metabolic syndrome and associated with significant cardiovascular morbidity and mortality. Recently, there has been an effort to pinpoint the pre-diabetic phase for early therapeutic intervention in the individual. These studies, in patients with impaired glucose intolerance, have shown to be beneficial from both lifestyle change and pharmacological intervention. It is thus hypnotized that intervention in patients with insulin resistance with or without glucose intolerance may prevent the progress of type 2 diabetes and it's complications. There is difficulty in identifying individuals who are at high risk for type 2 diabetes. The prevention strategy relies on intervention in a pre-diseased state. In the case of type 2 diabetes, the early intervention is useful in the phase where there is insulin resistance, but prior to the appearance of glucose intolerance. The diagnosis of insulin resistance is a challenging one. The gold standard in diagnosing insulin resistance is the hyperinsulinemic-euglycemic clamp, but this method is not suitable for routine clinical use. Thus, less invasive methods for evaluation, like homeostasis model assessment (HOMA) and quantitative insulin sensitivity check index (QUICKI), were developed. There is a correlation between HOMA and QUICKI results and the hyperinsulinemic-euglycemic clamp. Both HOMA and QUICKI allow insulin resistance diagnosis. The results from those tests correlate with hyperinsulinemic-euglycemic clamp and allow diagnosing insulin resistance, however, those indexes require serum glucose, insulin measurements and quite complicated calculations. A new method was suggested, non-invasive, sensitive and simple, for the identification of insulin resistance. In normal individuals, in the presence of insulin, glucose is taken up by a variety of cells, undergoes glycolysis and enters the tricarboxylic acid cycle or fat synthesis. In either case, CO2 in produced as a by-product. This CO2 enters the circulation and is discarded by the lungs. The new method is based on the assumption that 13C-glucose is ingested as described and its by-product 13CO2 can be measured in the expired air. In type 2 diabetes and other states of insulin resistance glucose, uptake is impaired and results in blunted 13CO2 production. This hypothesis was tested by Lewanczuc et al. The writers compared the [13C]-glucose breath test with hyperinsulinemic-euglycemic clamp, HOMA and QUICKI indexes. They tested 26 patients at different stages of insulin sensitivity and reported a good correlation of the glucose breath test and the other indexes. We suggest testing a larger group of patients at high-risk to develop type 2 diabetes and compare the glucose breath test with HOMA index.
Immune Activation as a Cause of Insulin Resistance in Adults Living With HIV-1 on Effective Antiretroviral...
HIV InfectionsThe aim of this study is to characterize in non-viremic HIV-1 patients under antiretroviral therapy an immune activation profile that the investigators have previously shown to be strongly linked to hyperinsulinemia. This characterization will be carried out via 3 different approaches. First, the investigators will analyze the metabolites present in the plasma of patients presenting with the profile of interest. Second, the investigators will study the transcriptome of the peripheral blood mononuclear cells of these patients. Finally, the investigators will search whether some factors released by these cells are able to induce insulin resistance. In addition the ability of the profile of interest to predict an increase in insulinemia over time will be assessed.
Insulin Resistance And End Stage Renal Disease: The Role Of Retinol Binding Protein 4
Insulin ResistanceDiabetes1 moreThe purpose of this study is to determine whether Retinol binding protein 4 has a role in insulin resistance development in patients suffering from end stage renal disease on hemodialysis.
(Mol-SHARE) Molecular Study of Health Assessment and Risk in Ethnic Groups
Insulin ResistanceType 2 Diabetes Mellitus1 moreThe purpose of this study is to directly compare the body composition, body fat distribution, and morphological and functional features of adipose tissue and skeletal muscle between South Asians and European Caucasians.
The Role of Insulin Resistance in Patients With Heart Failure and Type 2 Diabetes
Insulin ResistanceChronic Heart FailureThe purpose of this cross-sectional comparative 2x2 trial study is to compare the degree of insulin resistance, myocardial function and selected metabolic parameters and to explore the pathophysiological mechanisms by which insulin resistance is implicated in development of chronic heart failure (HF) in patients with type 2 diabetes and prediabetes (T2D). Investigators hypothesize that patients with heart failure will be insulin-resistant and will display metabolic abnormalities as patients with diabetes.
Regional Fat Depots and Insulin Resistance
ObesityInsulin Resistance1 moreThe biological basis for insulin resistance associated with obesity is unknown. By studying equally-overweight/obese individuals who are either insulin resistant or insulin sensitive, the investigators will compare characteristics of fat tissue to test several hypotheses: 1) impaired differentiation and fat storage in the subcutaneous fat depot characterize insulin resistant individuals, who have, as a result, fat in other tissues like liver and muscle, as well as more fat circulating in the blood; 2) inflammation is greater in visceral and/or subcutaneous adipose tissue depots in insulin resistant individuals as compared with insulin sensitive individuals.
Metabolic Syndrome in an Elderly Population is More Linked to Insulin Resistance Than to Obesity...
Metabolic Syndrome in the ElderlyIn the United States cardiovascular disease (CVD) accounts for 1 in every 2.8 deaths and is the leading cause of death among men and women 65 years or older (1). Studies have shown that the risk for cardiovascular disease is higher in individuals with the Metabolic Syndrome (2). Metabolic Syndrome (MBS) is defined by the Adult Treatment Panel III (ATP III) guidelines as a group of risk factors that includes 3 or more of the following: abdominal obesity, hypertriglyceridemia, low high-density lipoprotein (HDL) cholesterol, high blood pressure, and high fasting glucose (3). These factors place individuals at increased risk for the development of both cardiovascular disease (CVD) and diabetes mellitus (3). It is commonly held that insulin resistance is the driving force for the development of the MBS. Although there is a significant increase in incidence of MBS in the elderly, there are few studies that specifically examined MBS in that population. The prevailing opinion is that the strikingly high prevalence of the MBS in the elderly is due to concurrent obesity - i.e., the population gains weight as it ages, and development of the MBS accompanies the weight gain. However, while it is true that becoming obese may decrease insulin sensitivity, it has also been demonstrated that not all obese individuals are insulin resistant. Some studies suggest that up to 40% of obese individuals demonstrate normal insulin sensitivity (4). In addition, it is notable that the rate of increasing MBS in the population exceeds that of the rate of increasing BMI, suggesting that, while BMI may be a modulating factor, another factor independent of obesity also contributes to the development of MBS in the elderly. It is the investigators hypothesize that the MBS in the obese elderly population is primarily linked to insulin resistance and not to obesity per se. The investigators propose to test this hypothesis by assessing MBS and insulin resistance in a population of obese elderly men and women and then determining whether or not the MBS tracks with insulin resistance.