In Protocol #2, we will select 30 obese pubertal and 30 obese prepubertal subjects with an abnormal cytokine profile (i.e. fibrinogen and/or hsCRP concentration greater than or equal to 2 Standard Deviations (SD) above the mean established in our lab for lean controls in Protocol #1). They will be randomly assigned to either lifestyle intervention (diet/exercise) or diet/exercise plus metformin for 6 months. After the 6 month evaluation the subjects will cross over the treatment arms, i.e., those that were doing diet/exercise intervention only will add metformin, those that were doing the diet/exercise plus metformin will discontinue the metformin and continue with diet/exercise changes only. Intrahepatic fat contents will be measured as well. The investigators hypothesize that obese children in these age groups will have increased cardiovascular risk related to their obese state before reaching the currently defined criteria of metabolic syndrome. The investigators hypothesize that these cardiovascular risks can be reduced with lifestyle and drug interventions.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
66
Metformin, 250mg by mouth twice a day with meals will be started and if tolerated increased to 500mg twice a day in 3 days in those less than 12 years old and titrated further to 1000mg twice a day if tolerated.
The life style intervention changes will include a hypocaloric diet representing at least a 500 kcal/day reduction based on their dietary histories and Resting Energy Expenditure (REE) determined by the initial calorimetry.
Participants will attend the Fitness Center 3 times per week and supervised by an exercise technician or exercise specialist. Exercise will be individually prescribed for each participant based on their functional abilities. Exercise will consist of 5-10 minutes for warm up and stretching, followed by 15-30 minutes of cardiovascular exercise (i.e. treadmill, bicycle ergometer, rower, nustep, etc), 10-20 minutes of strength training (supervised using weight stack equipment), and 5-10 minutes of cool down and stretching. As children typically do not need an exercise prescription based on heart rate, we will familiarize them with perceived exertion scales and monitor that they are exercising in the moderate to hard range of perception of effort. Participants will be started at 15 minutes of cardiovascular exercise and 10 minutes of strength training exercise, progressing by 2-3 minutes every week until 30 and 20 minutes is achieved for each respectively.
Nemours Children's Clinic
Jacksonville, Florida, United States
Change From Baseline in High-sensitivity C-reactive Protein (hsCRP) at 6 Months
Value at 6 months minus value at baseline. HsCRP is an acute phase protein which is a sensitive marker for systemic inflammation. HsCRP concentrations were measured in our laboratory by immuno-nephelometry (Siemens Healthcare Diagnostics, Deerfield IL, USA), with an hsCRP lower sensitivity of 0.156 mg/L.
Time frame: Baseline and 6 months
Change From Baseline in Fibrinogen at 6 Months
Value at 6 months minus value at baseline. Fibrinogen is a hepatic-derived factor directly involved in clotting and in the viscosity characteristics of blood flow. It binds to platelets and contributes to their aggregation, promotes fibrin formation and is also an acute phase reactant that is increased in inflammatory states. Fibrinogen concentrations were measured in our laboratory by immuno-nephelometry (Siemens Healthcare Diagnostics, Deerfield IL, USA).
Time frame: Baseline and 6 months
Change From Baseline in Interleukin 6 (IL-6) at 6 Months
Value at 6 months minus value at baseline. IL-6 is a pro-inflammatory cytokine thought to produce a state of low-grade inflammation in obese individuals. IL-6 stimulates hepatic production of C-reactive protein (CRP), an acute phase protein which is a sensitive marker for systemic inflammation. IL-6 was measured by enzyme-linked immunosorbent assay (ELISA; R\&D Systems, Minneapolis, MN, USA).
Time frame: Baseline and 6 months
Change From Baseline in Plasminogen Activator Inhibitor-1 (PAI-1) at 6 Months
Value at 6 months minus value at baseline. PAI-1 is the primary physiological inhibitor of fibrinolysis and proteolysis. High PAI-1 levels have been linked to thrombosis and fibrosis, insulin resistance and obesity. PAI-1 was measured by ELISA (American Diagnostica, Stamford, CT, USA).
Time frame: Baseline and 6 months
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