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

NCT04715022 | Recruiting Phase 1 FDA Drug

• 1 other identifier: STUDY00146744
• Study Type: interventional
• Target: 23
• Locations: 1 country
• Sites: 1

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.

Conditions

Hypertension; Cardiovascular Diseases

Outcome Measures

Primary Outcomes (4)

• Efficacy of infusion of ascorbic acid

  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.

  30 minutes

• Efficacy of infusion of ascorbic acid

  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.

  60 minutes

• Efficacy of infusion of ascorbic acid

  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.

  90 minutes

• Efficacy of infusion of ascorbic acid

  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.

  120 minutes

Study Arms (2)

Placebo infusion

PLACEBO COMPARATOR

Saline will be administered over 2 hours

Drug: Saline

Ascorbic acid infusion

ACTIVE COMPARATOR

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.

Drug: Ascorbic acid solution (American Regent Laboratories Inc.)

Interventions

Ascorbic acid solution (American Regent Laboratories Inc.) DRUG

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.

Ascorbic acid infusion

Saline DRUG

Placebo (saline) will be administered

Placebo infusion

Eligibility Criteria

• Age: 35 Years - 65 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

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

Sponsors & Collaborators

• University of Kansas Medical Center: lead

Study Sites (1)

University of Kansas Medical Center

Kansas City, Kansas, 66160, United States

RECRUITING

MeSH Terms

Conditions

Hypertension; Cardiovascular Diseases

Interventions

Sodium Chloride

Condition Hierarchy (Ancestors)

Vascular Diseases

Intervention Hierarchy (Ancestors)

Chlorides; Hydrochloric Acid; Chlorine Compounds; Inorganic Chemicals; Sodium Compounds

Study Officials

• Seth Holwerda, PhD

  University of Kansas Medical Center

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Seth Holwerda, PhD

CONTACT

9729223230; sholwerda@kumc.edu

Manuel Clark, MPA

CONTACT

913-945-5763; mclark16@kumc.edi

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: PARTICIPANT, INVESTIGATOR
• Purpose: TREATMENT
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Principal Investigator

Study Record Dates

• First Submitted: January 10, 2021
• First Posted: January 20, 2021
• Study Start: June 17, 2021
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2027
• Last Updated: June 8, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)