Sympathetic-vascular Dysfunction in Obesity and Insulin Resistance (Vitamin C Study)

Conditions studied

Hypertension, Cardiovascular Diseases

About this study

The main purpose of research is to examine and understanding the development of hypertension in obese adults with insulin resistance. Findings from our studies will identify unique mechanisms that can be targeted to limit increases in vascular dysfunction and reduce the excessively high prevalence of hypertension and risk for cardiovascular disease (CVD). This study is testing the health of the blood vessels and the activity of the nerves that control the blood vessels in adults with insulin resistance. The extent to which ascorbic acid (Vitamin C) improves the function of the blood vessels will be determined. The primary outcome is blood pressure, which is the result of blood vessel health and activity of the nerves, and the reduction in blood pressure that is observed with ascorbic acid.

Interventions

• Drug: Ascorbic acid solution (American Regent Laboratories Inc.) — Ascorbic acid solution (American Regent Laboratories Inc.) will be obtained from the KU Investigational Pharmacy located in the KU Clinical Research Center where studies will take place. A priming bolus of 0.06 g ascorbic acid/kg fat free mass (FFM) dissolved in 100 mL of saline will be infused intravenously at 5 mL/min for 20 minutes, followed immediately by a "drip-infusion" of 0.02 g/kg FFM dissolved in 30 mL of saline administered over 2 hours at 0.5 mL/min.
• Drug: Saline — Placebo (saline) will be administered

Primary outcomes

• Efficacy of infusion of ascorbic acid (30 minutes)
• Efficacy of infusion of ascorbic acid (60 minutes)
• Efficacy of infusion of ascorbic acid (90 minutes)
• Efficacy of infusion of ascorbic acid (120 minutes)