The purpose of this study is to collect data to help researchers better understand the various causes of obesity, which may lead to the development of new obesity treatment options.
Obesity is major metabolic health concern and the potential beneficial effects of natriuretic peptides, specifically B-type natriuretic peptide (BNP) on adipocyte biology, energy expenditure and body weight could be of great significance. This study will provide insight into the mechanisms of dysregulation of the natriuretic peptides system in obesity and will contribute to delineate the roles and the clinical importance of BNP in the treatment of obesity.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
4
Translational Research Institute for Metabolism and Diabetes
Orlando, Florida, United States
Difference in level of B-type Natriuretic Peptide (BNP)
Blood samples will be obtained at baseline, during the infusion and after the termination of the infusion for measurement of levels of recombinant human BNP (rhBNP) and N-terminal pro-brain natriuretic peptide (NTpro-BNP).
Time frame: Days -2, 7, 14
Differences in the expression of NPRC
Natriuretic peptides Type-A and Type-C (NPRA,NPRC) expression will be measured by RT-PCR in subcutaneous abdominal adipose tissue samples obtained by percutaneous biopsy prior to infusion of rhBNP and related to the Metabolic Clearance Rate (MCR) for BNP
Time frame: Day 7
Determine whether short term infusion of rhBNP increases metabolic rate and/or fat oxidation
Energy expenditure and substrate oxidation rates will be measured for 30 min at baseline, prior to the infusion of BNP, then continuously during the rhBNP infusion in a 3200 Liters Flex Room Calorimeter respiratory chambers.
Time frame: Day 7
determine whether short term infusion of rhBNP alters gene expression in subcutaneous adipose tissue and skeletal muscle in a pattern consistent with activation of thermogenic pathways
Adipose tissue will be obtained from subcutaneous abdominal sites and skeletal muscle from the vastus lateralis by percutaneous biopsy prior to and after the infusion of rhBNP. The expression of Uncoupling Protein 1 (UCP1), Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1 α (PGC-1α), cytochrome c and PR domain containing 16 (PRDM16) (a significant factor in brown adipogenesis) will be measured by Reverse transcription polymerase chain reaction (RT-PCR).
Time frame: Day 7
Difference in responses of lean and obese subjects
Blood pressure and heart rate will be monitored at 10 minute intervals with an automated blood pressure cuff to measure physiological response and to monitor hemodynamic status and safety. Fractional sodium excretion, cGMP and creatinine, and total urine output in response to the rhBNP infusion will be compared in lean and obese subjects. Blood samples will be obtained at baseline, during the infusion and after termination of the infusion for measurement of cyclic Guanosine 3´,5´-Cyclic Monophosphate (cGMP), Plasma Renin Activity (PRA), Aldosterone (ALD), Renin (REN), NE, glucose, insulin, Non-essential fatty acid (NEFA), glycerol, adiponectin, C-Reactive Protein (CRP), Tumor Necrosis Factor- α (TNF-α) and other cytokines/chemokines.
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Time frame: Days -2, 7, 14