AtherosclerosisNCT00001461
Study of the Interaction Between the Cells Lining Blood Vessels and Angiotensin-Converting Enzyme
An observational study of Atherosclerosis and Coronary Disease, run by National Heart, Lung, and Blood Institute (NHLBI) at 1 site in United States.
Trial summary
The walls of blood vessels are lined by flat cells that are responsible for releasing substance(s) that control the activity of the blood vessel. These cells are referred to as the endothelium of the blood vessel. One of the substances released from the endothelium is called nitric oxide (NO). Read more about this study
- Who is it for?
- Any age
- Conditions the study is for
- Atherosclerosis, Coronary Disease
- How many people
- 209 participants
- Where
- 1 siteUnited States
- Study dates
- Mar 1995to Apr 2001
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages Any age
- All sexes
- No healthy volunteers
- Child, Adult, Older adult
Anyone with chest pain with known or suspected coronary artery disease.
Trial locations and contacts
1 site in 1 country.
United States1 site
National Heart, Lung and Blood Institute (NHLBI)
Bethesda, Maryland, 20892
About this study
Official title: Investigation of the Interaction Between the Vascular Endothelium and Angiotensin-Converting Enzyme
The walls of blood vessels are lined by flat cells that are responsible for releasing substance(s) that control the activity of the blood vessel. These cells are referred to as the endothelium of the blood vessel. One of the substances released from the endothelium is called nitric oxide (NO). This substance functions to keep blood vessels relaxed and to prevent blood from clotting inside the vessels.
Studies done by researchers in the Cardiology Branch of the National Heart, Lung and Blood Institute have shown that nitric oxide activity may be lower in patients with hardening of the arteries (atherosclerosis) and risk factors for atherosclerosis.
Read more
Another substance released by the cells of the endothelium is called bradykinin. It functions to stimulate the production of nitric oxide. Therefore bradykinin is also responsible for the relaxation and widening of blood vessels.
An enzyme found in the blood called angiotensin-converting enzyme (ACE) inactivates baradykinin and thereby decreases the production of nitric oxide. The activity of ACE is determined by genetics and is different in each person. Medications that block ACE (ACE-inhibitors) may be useful for patients with high levels of ACE activity.
This study is designed to determine;
- The role of bradkinin in stimulating the production of nitric oxide
- Whether ACE-inhibitors improve blood vessel relaxation caused by bradykinin
- Whether ACE-inhibitors improve abnormal blood vessel relaxation
- Whether ACE-inhibitors and bradykinin affect blood clotting
- Whether blood vessel response to ACE-inhibitor and bradykinin depends on the patients genetic make-up
Read the detailed description
The vascular endothelium tonically releases nitric oxide that produces smooth muscle relaxation, inhibition of platelet aggregation, and inhibition of cellular proliferation. Studies in the Cardiology Branch have demonstrated that nitric oxide activity is reduced in the coronary and peripheral vasculature of patients with atherosclerosis and in those with risk factors for atherosclerosis. Bradykinin, an endothelium-dependent vasodilator, may be an important modulator of vascular tone in vivo because it is tonically produced by the endothelium. Bradykinin is inactivated by angiotensin converting enzyme (ACE) that is found on the endothelial cell surface. The activity of plasma ACE is variable among individuals and is at least partly genetically determined. ACE activity may modulate the local vascular effects of bradykinin, and thus, ACE inhibitors would be expected to improve endothelium-dependent responses in patients with higher tissue ACE activity.
This protocol is designed to determine 1) the role of bradykinin in stimulating nitric oxide release in the human coronary and peripheral vasculature; 2) whether ACE inhibitors improve bradykinin-induced vasodilation, and if so, whether this occurs as a result of endothelium-dependent release of nitric oxide; 3) whether ACE inhibitors improve the abnormal shear-induced coronary vasodilation in patients with normal coronary arteries and those with coronary artery disease; 4) whether ACE inhibitors and bradykinin affect platelet function; 5) whether the vascular responses to ACE inhibition and bradykinin depend on the ACE genotype.
- Conditions
- Atherosclerosis, Coronary Disease
- Keywords
- Angiotensin Converting Enzyme, Angiotensin Converting Enzyme Inhibitors, Bradykinin, Endothelial Function, Nitric Oxide, Coronary Artery Disease
- Medical subject headings
- Atherosclerosis, Coronary Disease, Coronary Artery Disease
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Dec 2002 (estimated)
- Study startMar 1995
- Study completionApr 2001
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for AtherosclerosisStudies of the same condition, open and under way.
- More trials run by National Heart, Lung, and Blood Institute (NHLBI)The sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Enrolment
- 209 participants
Sponsor and investigators
- Sponsor type
- US National Institutes of Health
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00001461
- Sponsor's protocol ID
- 950099
- Other IDs
- 95-H-0099
- Status last verified
- Apr 2000
- First submitted
- 3 Nov 1999
- Last updated
- 4 Mar 2008
- Results posted
- No
Publications
Panza JA, Casino PR, Kilcoyne CM, Quyyumi AA. Role of endothelium-derived nitric oxide in the abnormal endothelium-dependent vascular relaxation of patients with essential hypertension. Circulation. 1993 May;87(5):1468-74. doi: 10.1161/01.cir.87.5.1468.
PubMed 8491001
Study at a glance
From the registry record, last updated by the sponsor on 4 Mar 2008. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Investigation of the Interaction Between the Vascular Endothelium and Angiotensin-Converting Enzyme
- ClinicalTrials.gov ID
- NCT00001461
- Acronym / sponsor ID
- 950099
- Conditions
- Atherosclerosis, Coronary Disease
- Keywords
- Angiotensin Converting Enzyme, Angiotensin Converting Enzyme Inhibitors, Bradykinin, Endothelial Function, Nitric Oxide, Coronary Artery Disease
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 209 participants
- Lead sponsor
- National Heart, Lung, and Blood Institute (NHLBI)US National Institutes of Health
- Study start
- Mar 1995
- Study completion
- Apr 2001
- First posted
- 10 Dec 2002 (estimated)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The walls of blood vessels are lined by flat cells that are responsible for releasing substance(s) that control the activity of the blood vessel. These cells are referred to as the endothelium of the blood vessel. One of the substances released from the endothelium is called nitric oxide (NO). This substance functions to keep blood vessels relaxed and to prevent blood from clotting inside the vessels.
Studies done by researchers in the Cardiology Branch of the National Heart, Lung and Blood Institute have shown that nitric oxide activity may be lower in patients with hardening of the arteries (atherosclerosis) and risk factors for atherosclerosis.
Another substance released by the cells of the endothelium is called bradykinin. It functions to stimulate the production of nitric oxide. Therefore bradykinin is also responsible for the relaxation and widening of blood vessels.
An enzyme found in the blood called angiotensin-converting enzyme (ACE) inactivates baradykinin and thereby decreases the production of nitric oxide. The activity of ACE is determined by genetics and is different in each person. Medications that block ACE (ACE-inhibitors) may be useful for patients with high levels of ACE activity.
This study is designed to determine;
- The role of bradkinin in stimulating the production of nitric oxide
- Whether ACE-inhibitors improve blood vessel relaxation caused by bradykinin
- Whether ACE-inhibitors improve abnormal blood vessel relaxation
- Whether ACE-inhibitors and bradykinin affect blood clotting
- Whether blood vessel response to ACE-inhibitor and bradykinin depends on the patients genetic make-up
Detailed description
The vascular endothelium tonically releases nitric oxide that produces smooth muscle relaxation, inhibition of platelet aggregation, and inhibition of cellular proliferation. Studies in the Cardiology Branch have demonstrated that nitric oxide activity is reduced in the coronary and peripheral vasculature of patients with atherosclerosis and in those with risk factors for atherosclerosis. Bradykinin, an endothelium-dependent vasodilator, may be an important modulator of vascular tone in vivo because it is tonically produced by the endothelium. Bradykinin is inactivated by angiotensin converting enzyme (ACE) that is found on the endothelial cell surface. The activity of plasma ACE is variable among individuals and is at least partly genetically determined. ACE activity may modulate the local vascular effects of bradykinin, and thus, ACE inhibitors would be expected to improve endothelium-dependent responses in patients with higher tissue ACE activity.
This protocol is designed to determine 1) the role of bradykinin in stimulating nitric oxide release in the human coronary and peripheral vasculature; 2) whether ACE inhibitors improve bradykinin-induced vasodilation, and if so, whether this occurs as a result of endothelium-dependent release of nitric oxide; 3) whether ACE inhibitors improve the abnormal shear-induced coronary vasodilation in patients with normal coronary arteries and those with coronary artery disease; 4) whether ACE inhibitors and bradykinin affect platelet function; 5) whether the vascular responses to ACE inhibition and bradykinin depend on the ACE genotype.
Study design
Who may qualify
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child, Adult, Older adult
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
Not reported in the source record.
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 4 Mar 2008.
- Background: PubMed 8491001Panza JA, Casino PR, Kilcoyne CM, Quyyumi AA. Role of endothelium-derived nitric oxide in the abnormal endothelium-dependent vascular relaxation of patients with essential hypertension. Circulation. 1993 May;87(5):1468-74. doi: 10.1161/01.cir.87.5.1468.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Atherosclerosis and Coronary Disease, run by National Heart, Lung, and Blood Institute (NHLBI) at 1 site in United States.
The full registered description is in the About this study section and the official record.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 4 Mar 2008. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT00001461, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 4 Mar 2008.