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The Role of Angiotensin Type I Receptor in the Regulation of Human Peripheral Vascular Function

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ClinicalTrials.gov Identifier: NCT00001628
Recruitment Status : Completed
First Posted : December 10, 2002
Last Update Posted : March 4, 2008
Sponsor:
Information provided by:
National Institutes of Health Clinical Center (CC)

Brief Summary:
The renin angiotensin system (RAS) plays an important physiological and pathophysiological role in the control of blood pressure and plasma volume. Inhibition of the RAS is useful in the treatment of hypertension, cardiac failure and in some patients with myocardial infarction. Several recent clinical trials with angiotensin converting enzyme inhibitors (ACEI) have shown that they also reduce the incidence of myocardial infarction, but the mechanisms underlying this anti-ischemic effect are poorly understood. ACEI reduce angiotensin II synthesis and prevent bradykinin degradation. Results from ongoing studies in the Cardiology Branch (Protocol 95-H-0099) designed to investigate the link between ACEI and the vascular endothelium indicate that ACEI improve peripheral endothelial function, an effect that is partially mediated by bradykinin. The current protocol is designed to investigate whether the beneficial effects of ACEI on peripheral endothelial function are also due to inhibition of angiotensin II. The recent development of selective angiotensin II type 1 (AT1) receptor antagonists allows us to specifically examine the effects of angiotensin II on vasomotor activity.

Condition or disease Intervention/treatment Phase
Atherosclerosis Heart Failure, Congestive Hypertension Myocardial Infarction Drug: Angiotensin II type 1 receptor antagonists Phase 3

Detailed Description:
The renin angiotensin system (RAS) plays an important physiological and pathophysiological role in the control of blood pressure and plasma volume. Inhibition of the RAS is useful in the treatment of hypertension, cardiac failure and in some patients with myocardial infarction. Several recent clinical trials with angiotensin converting enzyme inhibitors (ACEI) have shown that they also reduce the incidence of myocardial infarction, but the mechanisms underlying this anti-ischemic effect are poorly understood. ACEI reduce angiotensin II synthesis and prevent bradykinin degradation. Results from ongoing studies in the Cardiology Branch (Protocol 95-H-0099) designed to investigate the link between ACEI and the vascular endothelium indicate that ACEI improve peripheral endothelial function, an effect that is partially mediated by bradykinin. The current protocol is designed to investigate whether the beneficial effects of ACEI on peripheral endothelial function are also due to inhibition of angiotensin II. The recent development of selective angiotensin II type 1 (AT1) receptor antagonists allows us to specifically examine the effects of angiotensin II on vasomotor activity.

Study Type : Interventional  (Clinical Trial)
Enrollment : 36 participants
Primary Purpose: Treatment
Official Title: The Role of Angiotensin Type I Receptor in the Regulation of Human Peripheral Vascular Function
Study Start Date : July 1997
Study Completion Date : September 2000

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

Patients over 18 years with endothelial dysfunction requiring diagnostic cardiac catheterization.

Normal volunteers or patients undergoing catheterization who have normal coronary arteries without risk factors for atherosclerosis will be used as controls.

No unstable angina.

No significant left main disease (greater than 50% stenosis).

No recent myocardial infarction (less than 1 month).

No pregnancy, lactation.

No allergy to losartan.

No renal failure (creatinine greater than 2.5 mg/dl).

Ability to withdraw ACE inhibitors.


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): NCT00001628


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)

Publications:
ClinicalTrials.gov Identifier: NCT00001628     History of Changes
Other Study ID Numbers: 970140
97-H-0140
First Posted: December 10, 2002    Key Record Dates
Last Update Posted: March 4, 2008
Last Verified: June 1999

Keywords provided by National Institutes of Health Clinical Center (CC):
Angiotensin Receptor Antagonist
Atherosclerosis
Blood Flow
Endothelium
Endothelial Dysfunction

Additional relevant MeSH terms:
Heart Failure
Infarction
Myocardial Infarction
Atherosclerosis
Heart Diseases
Cardiovascular Diseases
Ischemia
Pathologic Processes
Necrosis
Myocardial Ischemia
Vascular Diseases
Arteriosclerosis
Arterial Occlusive Diseases
Angiotensin II
Angiotensinogen
Angiotensin Receptor Antagonists
Angiotensin II Type 1 Receptor Blockers
Vasoconstrictor Agents
Serine Proteinase Inhibitors
Protease Inhibitors
Enzyme Inhibitors
Molecular Mechanisms of Pharmacological Action