The Role of S-nitrosohemoglobin in Regulating Systemic Blood Flow During Hypoxia and Normoxia

December 28, 2016 updated by: Duke University

The Role of S-nitrosohemoglobin in Regulating Systemic Blood Flow Under Hypoxic and Normoxic Conditions

Nitric oxide is believed to contribute to regulation of blood flow by its selective binding to circulating hemoglobin (forming S-nitrosohemoglobin, SNO-Hb) and release in a PO2-dependent manner. This study is designed to test that hypothesis by measuring the effect of hypoxia and exercise on forearm blood flow before and after depletion of SNO-Hb using oral N-acetylcysteine.

Study Overview

Status

Terminated

Conditions

Intervention / Treatment

Detailed Description

NO has been shown to associate with erythrocytes in the form of SNO-Hb and can deliver vasomotor changes as erythrocytes pass through a physiologic O2 gradient. The aim of this study is to transiently deplete circulating SNO-Hb levels to prove that these levels are directly linked with the normal physiological vasodilation that occurs in response to brief hypoxia that occurs in moderate exercise. This study will be performed on healthy volunteers especially with no predisposing cardiovascular or respiratory conditions that may change their vasomotor response to hypoxia. Systemic blood flow will be approximated using non-invasive forearm venous occlusion plethysmography which will be performed initial to gather baseline data. The participants will then undergo 4 days of 600 mg BID oral N-acetylcysteine (NAC) solution treatment which acts as a bait reactant for NO groups bound to hemoglobin (SNO-Hb) and will then undergo retesting with forearm plethysmography. At the time of both blood flow measurements, arterial blood samples will also be gathered via an arterial catheter inserted on each of two testing days to determine SNO-Hb levels. Statistical analysis will include measuring the blunting of the hypoxia response and SNO-Hb levels using baseline testing as a self-control for each participant. Large scale human placebo-controlled trials with high-dose oral NAC (up to 8000 mg/day) for periods up to 12 months have shown no clinically significant adverse reactions, much less than in the proposed study.

Study Type

Interventional

Enrollment (Actual)

10

Phase

  • Early Phase 1

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • North Carolina
      • Durham, North Carolina, United States, 27710
        • Duke University Medical Center

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

18 years to 40 years (Adult)

Accepts Healthy Volunteers

Yes

Genders Eligible for Study

All

Description

Inclusion Criteria:

  • Healthy volunteers

Exclusion Criteria:

  • Pregnancy
  • smoking
  • pulmonary disease
  • cardiovascular disease

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: N-Acetylcysteine (NAC)
After initial measurements of SNO-Hb level, forearm blood flow in response to exercise and hypoxia, subjects will take oral NAC 600 mg twice daily. Measurements will then be repeated.
Drug: Oral N-acetylcysteine

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Time Frame
Forearm blood flow
Time Frame: 5 days
5 days

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Duke University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start

March 1, 2013

Primary Completion (Actual)

August 1, 2013

Study Completion (Actual)

August 1, 2013

Study Registration Dates

First Submitted

April 30, 2013

First Submitted That Met QC Criteria

July 19, 2013

First Posted (Estimate)

July 23, 2013

Study Record Updates

Last Update Posted (Estimate)

December 29, 2016

Last Update Submitted That Met QC Criteria

December 28, 2016

Last Verified

December 1, 2016

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • Pro00041312

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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