Insight Into New Brown Adipose Tissue Activators.

Overview

The general purpose of the study was to provide new information about the role of macronutrients intake, metabolomics, proteomics and microRNA on BAT activation. The invesigator evaluated BAT activity and whole body energy consumption under cold stimulation in two gruops of healthy males aged 21-43 years old with normal BMI ( 19-25kg/m2) and in overweight/obese subjects.

In detail, the main objectives of this study was to measure the influence of biological molecules of such fields: genomics, transcriptomics metabolomics and protemics and its relationship on BAT activation. The investigator also evaluated the role of diet, macronutirnets intake and polyunsaturated fatty acids on BAT activity. Study design: 1\. SCREENING VISIT: * obtaining written informed consent from all subjects * physical examination * body composition analysis ( DXA + bioindepedance method inbody 720) Laboratory analyses: * Oral glucose tolerance test ( OGGT 75g) * Morphology * CRP * Creatinine * Urine analysis * Lipids profile * TSH * ALT,AST Dietary analysis All subjects fulfilled a 3-day food diary. Subjects were asked to compare the portion sizes with the colour photographs of each portion size, and to weigh food, if possible. The daily total energy, macronutrients, monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), omega-3, and omega-6 fatty acids intake were analysed. 2\) STUDY VISITS: Patients who met the inclusion criteria and passed the screening stage were invited for the first visit when PET / MRI after 2h of cold exposure was performed. Subjects were studied in the morning, from approximately 8 a.m. to 12 a.m., after an overnight fast beginning at 10 p.m. the night before. At the beginning of the day on which the PET study was performed, a catheter was inserted in the subject's antecubital vein for a bolus injection of 18F-FDG. Another catheter was inserted in the antecubital vein of the contralateral arm and was used to obtain samples of venous blood. The subjects rested in a supine position under thermoneutral conditions (22°C) for 1 hour and then participants were exposed to cooling for 2 hours. The water perfused blankets were used in the applied protocol of cooling. Blood samples were taken before as well as in 60th and 120th min of cooling. Subjects were cooled until shivering and then temperature is set slightly (1-2°C) above the temperature that causes the onset of shivering. Shivering were confirmed by visual inspection and by asking the subject each 15 min. After 2 hour the tracer 18F-FDG (4 MBq/kg ) was administered intravenously, and scanning was performed after the injection of tracer. Skin temperatures were measured continually by means of electrode attached to skin below armpit. During the cold exposure, whole body resting energy expenditure (REE) was assessed by a computed open-circuit indirect calorimetry method- based on the consumption of O2 and the production of CO2. The 30 min long measurements of resting oxygen uptake and resting carbon dioxide production were performed by a ventilated canopy Vmax Encore 29n System (Viasys HealthCare, Yorba Linda, CA, USA) at the baseline ( -30 min to 0 min) and every 30 min until 120 min of cold exposure. During PET-MRI scanning blood samples were taken in 5', 10' 20' 30' 40' to check the activity of 18-FDG. After PET/MRI patient's urine was collected and analyzed for activity of tracer. Blood samples were taken for analysis before the cold exposure, at 60 min and 120 min during the cold exposure to evaluate: Glucose, IL-6, Insulin, Free Fatty Acids (FFA), TSH, fT4,fT3, Irisin, Atrial natriuretic peptide (ANP), Brain natriuretic peptide (BNP), plasma nonesterified fatty acid (NEFA), DNA, Peripheral Blood Mononuclear Cell (PBMC) for microRNA isolation, metabolomics and proteomics analysis. SUMMARY: The goal of our study is to search for new mechanisms that stimulate activation of BAT. It is likely that individuals with different content and activity of the brown adipose will have different set of serum markers after exposure to cold. This will allow the identification of new biomarkers and to understand the molecular mechanisms responsible for the activation of the brown adipose tissue. The outcomes will enable to find new potential therapeutic and diagnostic applications given to the current obesity pandemic.