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

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01905696
Recruitment Status : Terminated (Lack of funding)
First Posted : July 23, 2013
Last Update Posted : December 29, 2016
Information provided by (Responsible Party):
Duke University

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Focus is Determination of the Role of SNO-Hb in Forearm Blood Flow Regulation Drug: Oral N-acetylcysteine Early Phase 1

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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 10 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Basic Science
Official Title: The Role of S-nitrosohemoglobin in Regulating Systemic Blood Flow Under Hypoxic and Normoxic Conditions
Study Start Date : March 2013
Actual Primary Completion Date : August 2013
Actual Study Completion Date : August 2013

Resource links provided by the National Library of Medicine

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

Primary Outcome Measures :
  1. Forearm blood flow [ Time Frame: 5 days ]

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • Healthy volunteers

Exclusion Criteria:

  • Pregnancy
  • smoking
  • pulmonary disease
  • cardiovascular disease

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01905696

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United States, North Carolina
Duke University Medical Center
Durham, North Carolina, United States, 27710
Sponsors and Collaborators
Duke University
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Responsible Party: Duke University Identifier: NCT01905696    
Other Study ID Numbers: Pro00041312
First Posted: July 23, 2013    Key Record Dates
Last Update Posted: December 29, 2016
Last Verified: December 2016
Additional relevant MeSH terms:
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Antiviral Agents
Anti-Infective Agents
Respiratory System Agents
Free Radical Scavengers
Molecular Mechanisms of Pharmacological Action
Protective Agents
Physiological Effects of Drugs