Study of the Response of Human Small Blood Vessels

NCT ID: NCT00001622

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

87 participants

Study Classification

INTERVENTIONAL

Study Start Date

1997-03-31

Study Completion Date

2001-03-31

Brief Summary

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A layer of cells called the endothelium line the walls of blood vessels. These cells produce substances that control the tone of blood vessels and thus control blood flow through the vessel. One of the substances produced involved in the control of blood vessel function is nitric oxide. Nitric oxide (NO) plays a role in the relaxation of blood vessels.

Researchers have been interested in the function of the endothelium in patients with high blood pressure (essential hypertension) and patients with high cholesterol (hypercholesterolemia).

After conducting studies on the endothelium and nitric oxide, researchers have found that the endothelium is indeed functioning abnormally in patients with high blood pressure and high cholesterol. In addition, researchers have determined that the dysfunction is a result of abnormalities in the nitric oxide (NO) system.

In this study researchers plan to investigate the relationship between blood vessel responses in real-life settings versus laboratory settings in normal volunteers, patients with high blood pressure, and patients with high cholesterol.

Detailed Description

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Over the last ten years, we have been interested in the investigation of endothelial function in patients with essential hypertension and patients with hypercholesterolemia. We have performed intra-arterial infusion of endothelium-dependent and endothelium-independent drugs into the brachial artery with noninvasive measurement of the response of the forearm vasculature by means of strain gauge plethysmography. Those studies have allowed us to: a) demonstrate the presence of endothelial dysfunction in patients with essential hypertension and in patients with hypercholesterolemia; and b) identify an abnormality in the endothelium-derived nitric oxide system that is responsible for endothelial dysfunction in these patients. Further studies to more precisely determine the intracellular processes that mediate this abnormality in endothelial function in these patients are limited by the inherent shortcomings of the in vivo technique. An alternative possibility is the study of human small vessels in vitro; however, the relationship between in vivo and in vitro vascular responses to endothelium-dependent and -independent agonists has not been established. In the present study, we propose to investigate this relationship in normal volunteers, patients with essential hypertension, and patients with hypercholesterolemia.

Conditions

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Healthy Hypercholesterolemia Hypertension

Study Design

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Primary Study Purpose

TREATMENT

Interventions

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investigate the relationship between in vivo and in vitro vascular responses

Intervention Type PROCEDURE

Eligibility Criteria

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Inclusion Criteria

Patients in whom the blood pressure remains at normal levels 2 weeks after withdrawal of antihypertensive treatment will be closely monitored until they become hypertensive, at which time they will undergo the study. Patients in whom blood pressure does not increase after 2 months of discontinuation of therapy will be excluded from the study.

Patients with coexistent hypertension and hypercholesterolemia are ineligible.

Normal volunteers who are not taking any kind of medication are eligible.

No history of diabetes, peripheral vascular disease, coagulopathy, or any other disease predisposing to vasculitis or Raynaud's phenomenon.

No history of keloid formation.

All patients must be capable of giving informed consent for all procedures.
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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Furchgott RF. Role of endothelium in responses of vascular smooth muscle. Circ Res. 1983 Nov;53(5):557-73. doi: 10.1161/01.res.53.5.557. No abstract available.

Reference Type BACKGROUND
PMID: 6313250 (View on PubMed)

Falloon BJ, Heagerty AM. In vitro perfusion studies of human resistance artery function in essential hypertension. Hypertension. 1994 Jul;24(1):16-23. doi: 10.1161/01.hyp.24.1.16.

Reference Type BACKGROUND
PMID: 8021003 (View on PubMed)

Goode GK, Heagerty AM. In vitro responses of human peripheral small arteries in hypercholesterolemia and effects of therapy. Circulation. 1995 Jun 15;91(12):2898-903. doi: 10.1161/01.cir.91.12.2898.

Reference Type BACKGROUND
PMID: 7796498 (View on PubMed)

Other Identifiers

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97-H-0098

Identifier Type: -

Identifier Source: secondary_id

970098

Identifier Type: -

Identifier Source: org_study_id

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