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Study of the Response of Human Small Blood Vessels

This study has been completed.
Sponsor:
ClinicalTrials.gov Identifier:
NCT00001622
First Posted: December 10, 2002
Last Update Posted: March 4, 2008
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.
Information provided by:
National Institutes of Health Clinical Center (CC)
  Purpose

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.


Condition Intervention Phase
Healthy Hypercholesterolemia Hypertension Procedure: investigate the relationship between in vivo and in vitro vascular responses Phase 1

Study Type: Interventional
Study Design: Primary Purpose: Treatment
Official Title: Study of the Relation Between In Vivo and In Vitro Response of Human Small Vessels

Resource links provided by NLM:


Further study details as provided by National Institutes of Health Clinical Center (CC):

Estimated Enrollment: 87
Study Start Date: March 1997
Estimated Study Completion Date: March 2001
Detailed Description:
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.
  Eligibility

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Senior
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Patients (men and nonpregnant women) with systemic hypertension, patients with hypercholesterolemia, and normal volunteers.

All blood pressure recordings must be consistently elevated.

No renovascular hypertension or other etiologies for elevated blood pressure.

No definite evidence of accelerated or malignant hypertension (diastolic pressures above 115 mmHg, with associated encephalopathic changes, papilledema, progressive renal failure, or congestive heart failure), or serious intercurrent illness.

Patients in whom withdrawal of antihypertensive medications is considered hazardous are ineligible.

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.

  Contacts and Locations
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 ClinicalTrials.gov identifier (NCT number): NCT00001622


Locations
United States, Maryland
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, Maryland, United States, 20892
Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
  More Information

Publications:
ClinicalTrials.gov Identifier: NCT00001622     History of Changes
Other Study ID Numbers: 970098
97-H-0098
First Submitted: November 3, 1999
First Posted: December 10, 2002
Last Update Posted: March 4, 2008
Last Verified: January 2000

Keywords provided by National Institutes of Health Clinical Center (CC):
Endothelium
Hypercholesterolemia
Hypertension
Microvessels
Vasodilation
Normal Volunteer

Additional relevant MeSH terms:
Hypertension
Hypercholesterolemia
Vascular Diseases
Cardiovascular Diseases
Hyperlipidemias
Dyslipidemias
Lipid Metabolism Disorders
Metabolic Diseases