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

Phase 1

Recruiting

• Conditions: Hypertension; Cardiovascular Diseases
• Interventions: Drug: Saline; Drug: Ascorbic acid solution (American Regent Laboratories Inc.)

• Registration Number: NCT04715022
• Lead Sponsor: University of Kansas Medical Center

Brief Summary

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.

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2021-01-10
• Study First Submitted QC: 2021-01-14
• Study First Posted: 2021-01-20
• Study Start: 2021-06-17
• Status Verified: 2023-10
• Last Update Submitted: 2023-10-20
• Last Update Posted: 2023-10-24
• Primary Completion: 2025-04-01
• Study Completion: 2025-04-01

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 23

Inclusion Criteria

1. Obese: BMI >30 m/kg2
2. Middle-aged: 35-65 years
3. Participants must be willing and able to discontinue taking any vitamin C or E supplements or omega-3 fatty acids beginning 2 weeks prior.
4. Able and willing to provide written informed consent

Exclusion Criteria

1. Diabetes mellitus: fasting glucose < 1267 mg/dL and/or HbA1c < 6.5%
2. Currently taking a statin or antihypertension medication
3. Hyperlipidemia: Fasting triglycerides < 250 mg/dL
4. Hypertension: <130/80 mmHg
5. History of heart disease (e.g., myocardial infarction, stent)
6. History of vascular disease (e.g., bypass, stroke)

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: CROSSOVER

Arm && Interventions

Group	Intervention	Description
Placebo infusion	Saline	Saline will be administered over 2 hours
Ascorbic acid infusion	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 University of Kansas (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.

Primary Outcome Measures

Name	Time	Method
Efficacy of infusion of ascorbic acid	120 minutes	The difference in sympathetic-vascular transduction (mmHg) between ascorbic acid and placebo infusion will be taken as a measure of the modulation of SVT by oxidative stress.

Trial Locations

Locations (1)

University of Kansas Medical Center; 🇺🇸 Kansas City, Kansas, United States