This study evaluates the hypothesis that a meal constituted of only glucose produces differences in the brain blood flow in people with obesity that are not observed in people without obesity. These changes, at least in part, could explain the mechanisms involved in maintenance or development of obesity.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Enrollment
20
A solution composed by 75 grams of glucose and water at ambient temperature is administered to each volunteer, being of the with obesity group or the without obesity group, as follow: * 300 mL final volume of the solution. * Time of oral ingestion inferior than 2 minutes. * 30 minutes before the radiopharmaceutical injection. * 12 hours fasting minimum.
Pure water at ambient temperature is administered to each volunteer, being of the with obesity group or the without obesity group, as follow: * 300 mL final volume of the solution. * Time of oral ingestion inferior than 2 minutes. * 30 minutes before the radiopharmaceutical injection. * 12 hours fasting minimum.
Clinical Hospital of Ribeirao Preto
Ribeirão Preto, São Paulo, Brazil
Regional cerebral blood flow (rCBF) changes after a meal challenge, measured by Single Single-photon emission computed tomography (SPECT) and statistical parametric mapping.
Using 99m technetium ecd radiopharmaceutical, this study aims to detect rCBF differences between SPECT images performed after a meal challenge composed by 75 grams of glucose and water and also after a challenge constituted by only water (control), both ingested orally. This approach is performed in a group of 10 people with obesity and also in 10 people without obesity.
Time frame: 30 minutes after a meal challenge (time of radiopharmaceutical injection)
Blood levels mean differences within both groups, with and without obesity and across these groups, of hormones and metabolites by multiplexed assay using luminex technology and spectrophotometry, respectively.
This study looks for mean differences of blood levels within and across groups with and without obesity. The metabolites and hormones/cytokines measured are, respectively: glucose (measured by spectrophotometry), insulin, leptin, amylin, interleukin 6 (IL-6), tumor necrosis factor alpha, active ghrelin, peptide yy (PYY) and pancreatic polypeptide (PP) (multiplexed assay using luminex).
Time frame: 30 minutes before, at the time and 30, 60 and 90 minutes after the radiopharmaceutical injection.
Resting energy expenditure (REE) and body composition measurements by indirect calorimetry and electrical bioimpedance, respectively.
This study also aims to measure and compare the REE by indirect calorimetry with a Quark (Cosmed, Italy) calorimeter and the body composition by Byodinamics 450 (Biodynamics Corp., United States) within the two groups and across them.
Time frame: 6 hours before SPECT acquisition.
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