Study of Inherited Changes of Receptors Located on Blood Vessels

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: NCT00001741
Recruitment Status : Completed
First Posted : November 4, 1999
Last Update Posted : March 4, 2008
Information provided by:
National Institutes of Health Clinical Center (CC)

Brief Summary:

The renin angiotensin system is a complex process involving hormones and enzymes that regulate blood volume and blood pressure. The hormone angiotensin II is responsible for making blood vessels narrow or constrict. Angiotensin II is found in the blood and can attach to special sites called receptors on blood vessel walls. These receptors are programmed to accept angiotensin II and cause a constriction of the blood vessel. This function is found in the genetic information of each individual person.

Occasionally patients have changes in their genes related to angiotensin II receptors. These changes may result in the receptors acting differently to angiotensin II, which may affect the function of blood vessels.

This study is designed to improve researchers understanding of the physiological effects on blood vessels associated with mutations of the genes responsible for angiotensin II receptor function.

Condition or disease Intervention/treatment Phase
Cardiovascular Disease Drug: Losartan Phase 1

Detailed Description:
Polymorphisms in the genes encoding for various elements of the renin angiotensin system have been associated with cardiovascular disease. We have isolated novel alleles in the angiotensin II type I receptor gene. We propose this exploratory investigation to study the physiological effect of these mutations on vascular function in patients and family members who carry these rare alleles.

Study Type : Interventional  (Clinical Trial)
Enrollment : 200 participants
Primary Purpose: Treatment
Official Title: Study of Vascular Responsiveness in Subjects With Polymorphisms of the Angiotensin II Type I Receptor Gene
Study Start Date : November 1997
Study Completion Date : April 2003

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

Patients aged 21 or older with chronic orthostatic intolerance will be included.

There will be no exclusion from participation in the study on the basis of ethnicity/race.

Patients will be recruited in the Cardiology Branch outpatient clinic, Dr. David Goldstein (Chief Neurocardiology Section, NINDS, NIH), or from outside physicians.

Children will be excluded from the study because of inability in obtaining informed consent.

Cognitively impaired individuals, prisoners, or other institutionalized persons will not be able to participate.

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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): NCT00001741

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)

Publications: Identifier: NCT00001741     History of Changes
Other Study ID Numbers: 980029
First Posted: November 4, 1999    Key Record Dates
Last Update Posted: March 4, 2008
Last Verified: April 2003

Keywords provided by National Institutes of Health Clinical Center (CC):
Angiotensin II Receptor
Polymorphism, Genetic
Vascular Tone
Angiotensin II

Additional relevant MeSH terms:
Cardiovascular Diseases
Angiotensin II
Anti-Arrhythmia Agents
Antihypertensive Agents
Angiotensin II Type 1 Receptor Blockers
Angiotensin Receptor Antagonists
Molecular Mechanisms of Pharmacological Action
Vasoconstrictor Agents
Serine Proteinase Inhibitors
Protease Inhibitors
Enzyme Inhibitors