The purpose of this study is to find out if spironolactone, a drug that blocks the action of aldosterone, can make the blood vessels work better in people with obesity. The investigators also want to find out whether spironolactone causes changes in levels of insulin and markers of inflammation.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
38
50 mg once daily for 6 weeks.
Placebo-matching spironolactone once daily for 6 weeks.
Brigham and Women's Hospital
Boston, Massachusetts, United States
Change From Baseline in Post-ischemic Dilatation
Ultrasonography of the brachial artery was performed to evaluate endothelial function by flow mediated dilatation (FMD) studies. A blood pressure cuff was placed on the participant's upper arm and was compressed for 5 minutes. After release of compression, brachial artery diameter and blood flow velocity were measured. FMD was expressed as the percentage change in brachial artery diameter. A positive change from Baseline indicates improvement.
Time frame: Baseline and Week 6
Change From Baseline in Para-aminohippurate (PAH) Clearance
Renal plasma blood flow was determined by clearance of para-aminohippurate (PAH). A loading dose of PAH (8 mg/kg) was given intravenously followed by a 1 hour constant infusion of PAH at a rate of 12 mg/minute (min). Plasma samples were obtained at Baseline and at 50 and 60 minutes. PAH clearance was calculated from the plasma levels and infusion rates and reported in millimeters (mL)/minute (min). A positive change from Baseline indicates improvement.
Time frame: Baseline and Week 6 (Prior to PAH infusion and at 50 and 60 minutes post PAH infusion)
Change From Baseline in Markers of Inflammation
Blood was to be collected and tested for Tumor Necrosis Factor Alpha (TNF-α) and Monocyte Chemotactic Protein-1 (MCP-1), markers of inflammation; However, due to lack of funding, blood samples were not analyzed and data for levels of inflammation markers were not collected.
Time frame: Baseline and Week 6
Change From Baseline in Insulin Sensitivity Index (ISI)
Insulin sensitivity was measured using the 75 gram (G) glucose tolerance test. Participants ingested 75 grams of glucose in 300-400 milliliters (mL) of water over 5 minutes. Blood samples were taken before ingesting glucose and then every 30 minutes for 120 minutes. Insulin sensitivity index was calculated by Matsuda and Defronzo's formula using the values obtained. A positive change from Baseline (increase in insulin sensitivity) indicates improvement.
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Time frame: Baseline and Week 6 (Prior to ingesting glucose and every 30 minutes for 120 minutes)
Change From Baseline in Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)
Insulin resistance was measured using the 75 G glucose tolerance test. Participants ingested 75 grams of glucose in 300-400 mL of water over 5 minutes. Blood samples were taken before ingesting glucose and then every 30 minutes for 120 minutes. HOMA-IR was calculated using the Insulin and glucose levels obtained. A negative change (decrease in insulin resistance) indicates improvement.
Time frame: Baseline and Week 6 (Prior to ingesting glucose and every 30 minutes for 120 minutes)