Vascular Effects of Endothelium-Derived Versus Hemoglobin-Transported Nitric Oxide in Healthy Subjects

NCT ID: NCT00001963

Last Updated: 2008-03-04

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

COMPLETED

Clinical Phase

PHASE1

Total Enrollment

28 participants

Study Classification

INTERVENTIONAL

Study Start Date

1999-12-31

Study Completion Date

2000-10-31

Brief Summary

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Nitric oxide (NO) is a soluble gas, continuously synthesized by the endothelium, that contributes importantly to vasodilator tone of the coronary and systemic circulations by activating guanylyl cyclase in vascular smooth muscle, causing relaxation. Although regional synthesis of NO by the endothelium contributes to local vasodilator tone, Stamler and co-workers have proposed that regional vascular tone may also be regulated by NO transported from the lungs by hemoglobin as a consequence of enhanced binding of NO to reactive thiols of oxygenated hemoglobin. This study is designed to determine the contribution of hemoglobin-transported NO to forearm microvascular dilator tone in healthy subjects at rest and during regional hypoxia associated with forearm exercise stress, with measurements made before and after regional blockade of endothelial NO synthesis. Findings in this study may be relevant to understanding the physiological contribution and therapeutic potential of hemoglobin-transported NO in the regulation of vasodilator tone in diseases and conditions associated with regional endothelial dysfunction and reduced endothelial NO bioactivity (e.g., hypertension, diabetes mellitus, hypercholesterolemia, cigarette smoking, and estrogen deficiency).

Detailed Description

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Nitric oxide (NO) is a soluble gas, continuously synthesized by the endothelium, that contributes importantly to vasodilator tone of the coronary and systemic circulations by activating guanylyl cyclase in vascular smooth muscle, causing relaxation. Although regional synthesis of NO by the endothelium contributes to local vasodilator tone, Stamler and co-workers have proposed that regional vascular tone may also be regulated by NO transported from the lungs by hemoglobin as a consequence of enhanced binding of NO to reactive thiols of oxygenated hemoglobin. This study is designed to determine the contribution of hemoglobin-transported NO to forearm microvascular dilator tone in healthy subjects at rest and during regional hypoxia associated with forearm exercise stress, with measurements made before and after regional blockade of endothelial NO synthesis. Findings in this study may be relevant to understanding the physiological contribution and therapeutic potential of hemoglobin-transported NO in the regulation of vasodilator tone in diseases and conditions associated with regional endothelial dysfunction and reduced endothelial NO bioactivity (e.g., hypertension, diabetes mellitus, hypercholesterolemia, cigarette smoking, and estrogen deficiency).

Conditions

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Diabetes Mellitus Healthy Hypercholesterolemia Hypertension

Study Design

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Primary Study Purpose

TREATMENT

Interventions

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hemoglobin-transported nitric oxide

Intervention Type PROCEDURE

Eligibility Criteria

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Inclusion Criteria

All volunteer subjects must be between 21 and 75 years of age, in good health, and must have provided informed, written consent for participation in this study.

No subjects with a history or evidence of present or past hypertension (blood pressure greater than 145/95 mmHg), hypercholesterolemia (LDL cholesterol greater than 130 mg/dL), diabetes mellitus (fasting blood glucose greater than 120 mg/dL), smoking within 2 years, cardiac disease, peripheral vascular disease, coagulopathy, or any other disease predisposing to vasculitis or Raynaud's phenomenon.

No volunteer subject will be allowed to take any medication (oral contraceptive agents are allowed) or vitamin supplements for at least one month prior to study and will not be allowed to take aspirin for one week prior to study.

Pregnancy testing will be required of all women of reproductive age to exclude current pregnancy.
Eligible Sex

ALL

Accepts Healthy Volunteers

Yes

Sponsors

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National Heart, Lung, and Blood Institute (NHLBI)

NIH

Sponsor Role lead

Locations

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National Heart, Lung and Blood Institute (NHLBI)

Bethesda, Maryland, United States

Site Status

Countries

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United States

References

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Jia L, Bonaventura C, Bonaventura J, Stamler JS. S-nitrosohaemoglobin: a dynamic activity of blood involved in vascular control. Nature. 1996 Mar 21;380(6571):221-6. doi: 10.1038/380221a0.

Reference Type BACKGROUND
PMID: 8637569 (View on PubMed)

Gow AJ, Stamler JS. Reactions between nitric oxide and haemoglobin under physiological conditions. Nature. 1998 Jan 8;391(6663):169-73. doi: 10.1038/34402.

Reference Type BACKGROUND
PMID: 9428761 (View on PubMed)

Palmer RM, Ashton DS, Moncada S. Vascular endothelial cells synthesize nitric oxide from L-arginine. Nature. 1988 Jun 16;333(6174):664-6. doi: 10.1038/333664a0.

Reference Type BACKGROUND
PMID: 3131684 (View on PubMed)

Other Identifiers

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00-H-0031

Identifier Type: -

Identifier Source: secondary_id

000031

Identifier Type: -

Identifier Source: org_study_id

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