Cardiovascular DiseasesNCT00005757
Racial Variation in ACE--Genetic and Physiologic Bases
An observational study of Cardiovascular Diseases and Heart Diseases, run by Vanderbilt University.
Trial summary
To determine whether differences in the activity of the renin-angiotensin and bradykinin systems are involved in the pathogenesis of blood pressure variation in African Americans. Read more about this study
- Who is it for?
- Ages Up to 100 years, men only
- Conditions the study is for
- Cardiovascular Diseases, Heart Diseases, Hypertension
- How many people
- 293 participants
- Where
- No sites listed yet
- Study dates
- Sep 1997to Aug 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 Up to 100 years
- Men only
- No healthy volunteers
- Child, Adult, Older adult
No eligibility criteria
About this study
To determine whether differences in the activity of the renin-angiotensin and bradykinin systems are involved in the pathogenesis of blood pressure variation in African Americans.
Read the detailed description
BACKGROUND:
Each year, more than 40,000 new patients require treatment for end stage renal disease, a condition which is 4-fold higher among African Americans than Caucasians. Trials of angiotensin converting enzyme inhibitors (ACEIs) in Caucasians support a role of the renin-angiotensin system in the pathogenesis of glomerulosclerosis. Yet, despite the high prevalence of nephropathy among African Americans, Blacks have been under-represented in studies in ACEIs. Data from our laboratory suggest that the renal effects of ACEI may differ in African Americans. African Americans are resistant to the anti-hypertensive effects of ACEI and, thus, may be resistant to the renoprotective effects as well. The ACE deletion allele, a variant associated with increased ACE activity and progression of renal diseases, is increased in frequency in African Americans, while the frequency of the Ang AT1 receptor C allele, a variant associated with antihypertensive responsiveness to ACEI is decreased. Moreover, African Americans exhibit decreased sensitivity to Ang I and increased sensitivity to bradykinin. Taken together, these data suggest the hypothesis that ACE activity is increased in African Americans, leading to decreased bradykinin levels ( and receptor sensitization) and increased tissue Ang II (and receptor desensitization).
DESIGN NARRATIVE:
The study tests the hypothesis that ACE activity is increased in African Americans, leading to decreased bradykinin levels (and receptor sensitization) and increased tissue Ang II (and receptor desensitization). The effects of race, hypertension and ACE insertion/deletion genotype on ACE activity will be determined, as measured by the pressor and renal vasoconstrictor responses to Ang I and Ang II and the vasodilator response to bradykinin. Specific bradykinin and angiotensin receptor antagonists will be used to determine the relative contribution of increased bradykinin and decreased angiotensin II to the renal hemodynamic effects of ACEIs in African Americans and Caucasians.
- Conditions
- Cardiovascular Diseases, Heart Diseases, Hypertension
- Medical subject headings
- Cardiovascular Diseases, Heart Diseases, Hypertension
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted26 May 2000 (estimated)
- Study startSep 1997
- Primary completionAug 2001
- Study completionAug 2001
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (9)Papers the sponsor has linked to this study.
- Other trials for Cardiovascular DiseasesStudies of the same condition, open and under way.
- 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
- Observational model
- Case crossover
- Enrolment
- 293 participants (actual)
Sponsor and investigators
- Lead sponsor
- Vanderbilt University
- Sponsor type
- University, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Investigators
- Nancy Brown, Vanderbilt University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00005757
- Sponsor's protocol ID
- 5115
- Other IDs
- R29HL056963
- Status last verified
- Nov 2016
- First submitted
- 25 May 2000
- Last updated
- 28 Nov 2016
- Results posted
- No
Publications
Brown NJ, Agirbasli MA, Williams GH, Litchfield WR, Vaughan DE. Effect of activation and inhibition of the renin-angiotensin system on plasma PAI-1. Hypertension. 1998 Dec;32(6):965-71. doi: 10.1161/01.hyp.32.6.965.
PubMed 9856958Gainer JV, Morrow JD, Loveland A, King DJ, Brown NJ. Effect of bradykinin-receptor blockade on the response to angiotensin-converting-enzyme inhibitor in normotensive and hypertensive subjects. N Engl J Med. 1998 Oct 29;339(18):1285-92. doi: 10.1056/NEJM199810293391804.
PubMed 9791144Murphey LJ, Hachey DL, Vaughan DE, Brown NJ, Morrow JD. Quantification of BK1-5, the stable bradykinin plasma metabolite in humans, by a highly accurate liquid-chromatographic tandem mass spectrometric assay. Anal Biochem. 2001 May 1;292(1):87-93. doi: 10.1006/abio.2001.5073.
PubMed 11319821Gainer JV, Brown NJ, Bachvarova M, Bastien L, Maltais I, Marceau F, Bachvarov DR. Altered frequency of a promoter polymorphism of the kinin B2 receptor gene in hypertensive African-Americans. Am J Hypertens. 2000 Dec;13(12):1268-73. doi: 10.1016/s0895-7061(00)01215-2.
PubMed 11130770Murphey LJ, Kumar S, Brown NJ. Endogenous bradykinin and the renin and pressor responses to furosemide in humans. J Pharmacol Exp Ther. 2000 Nov;295(2):644-8.
PubMed 11046100Brown NJ, Nakamura S, Ma L, Nakamura I, Donnert E, Freeman M, Vaughan DE, Fogo AB. Aldosterone modulates plasminogen activator inhibitor-1 and glomerulosclerosis in vivo. Kidney Int. 2000 Sep;58(3):1219-27. doi: 10.1046/j.1523-1755.2000.00277.x.
PubMed 10972684Murphey LJ, Gainer JV, Vaughan DE, Brown NJ. Angiotensin-converting enzyme insertion/deletion polymorphism modulates the human in vivo metabolism of bradykinin. Circulation. 2000 Aug 22;102(8):829-32. doi: 10.1161/01.cir.102.8.829.
PubMed 10952948Murphey LJ, Hachey DL, Oates JA, Morrow JD, Brown NJ. Metabolism of bradykinin In vivo in humans: identification of BK1-5 as a stable plasma peptide metabolite. J Pharmacol Exp Ther. 2000 Jul;294(1):263-9.
PubMed 10871321Wilsdorf T, Gainer JV, Murphey LJ, Vaughan DE, Brown NJ. Angiotensin-(1-7) does not affect vasodilator or TPA responses to bradykinin in human forearm. Hypertension. 2001 Apr;37(4):1136-40. doi: 10.1161/01.hyp.37.4.1136.
PubMed 11304515
Study at a glance
From the registry record, last updated by the sponsor on 28 Nov 2016. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Racial Variation in ACE--Genetic and Physiologic Bases
- ClinicalTrials.gov ID
- NCT00005757
- Acronym / sponsor ID
- 5115
- Conditions
- Cardiovascular Diseases, Heart Diseases, Hypertension
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 293 participants (actual)
- Lead sponsor
- Vanderbilt UniversityUniversity, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Study start
- Sep 1997
- Primary completion
- Aug 2001 (actual)
- Study completion
- Aug 2001 (actual)
- First posted
- 26 May 2000 (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.
To determine whether differences in the activity of the renin-angiotensin and bradykinin systems are involved in the pathogenesis of blood pressure variation in African Americans.
Detailed description
BACKGROUND:
Each year, more than 40,000 new patients require treatment for end stage renal disease, a condition which is 4-fold higher among African Americans than Caucasians. Trials of angiotensin converting enzyme inhibitors (ACEIs) in Caucasians support a role of the renin-angiotensin system in the pathogenesis of glomerulosclerosis. Yet, despite the high prevalence of nephropathy among African Americans, Blacks have been under-represented in studies in ACEIs. Data from our laboratory suggest that the renal effects of ACEI may differ in African Americans. African Americans are resistant to the anti-hypertensive effects of ACEI and, thus, may be resistant to the renoprotective effects as well. The ACE deletion allele, a variant associated with increased ACE activity and progression of renal diseases, is increased in frequency in African Americans, while the frequency of the Ang AT1 receptor C allele, a variant associated with antihypertensive responsiveness to ACEI is decreased. Moreover, African Americans exhibit decreased sensitivity to Ang I and increased sensitivity to bradykinin. Taken together, these data suggest the hypothesis that ACE activity is increased in African Americans, leading to decreased bradykinin levels ( and receptor sensitization) and increased tissue Ang II (and receptor desensitization).
DESIGN NARRATIVE:
The study tests the hypothesis that ACE activity is increased in African Americans, leading to decreased bradykinin levels (and receptor sensitization) and increased tissue Ang II (and receptor desensitization). The effects of race, hypertension and ACE insertion/deletion genotype on ACE activity will be determined, as measured by the pressor and renal vasoconstrictor responses to Ang I and Ang II and the vasodilator response to bradykinin. Specific bradykinin and angiotensin receptor antagonists will be used to determine the relative contribution of increased bradykinin and decreased angiotensin II to the renal hemodynamic effects of ACEIs in African Americans and Caucasians.
Study design
- Observational model
- Case crossover
Who may qualify
- Ages
- Up to 100 years
- Sex
- Male only
- 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 28 Nov 2016.
- Background: PubMed 9856958Brown NJ, Agirbasli MA, Williams GH, Litchfield WR, Vaughan DE. Effect of activation and inhibition of the renin-angiotensin system on plasma PAI-1. Hypertension. 1998 Dec;32(6):965-71. doi: 10.1161/01.hyp.32.6.965.
- Background: PubMed 9791144Gainer JV, Morrow JD, Loveland A, King DJ, Brown NJ. Effect of bradykinin-receptor blockade on the response to angiotensin-converting-enzyme inhibitor in normotensive and hypertensive subjects. N Engl J Med. 1998 Oct 29;339(18):1285-92. doi: 10.1056/NEJM199810293391804.
- Background: PubMed 11319821Murphey LJ, Hachey DL, Vaughan DE, Brown NJ, Morrow JD. Quantification of BK1-5, the stable bradykinin plasma metabolite in humans, by a highly accurate liquid-chromatographic tandem mass spectrometric assay. Anal Biochem. 2001 May 1;292(1):87-93. doi: 10.1006/abio.2001.5073.
- Background: PubMed 11130770Gainer JV, Brown NJ, Bachvarova M, Bastien L, Maltais I, Marceau F, Bachvarov DR. Altered frequency of a promoter polymorphism of the kinin B2 receptor gene in hypertensive African-Americans. Am J Hypertens. 2000 Dec;13(12):1268-73. doi: 10.1016/s0895-7061(00)01215-2.
- Background: PubMed 11046100Murphey LJ, Kumar S, Brown NJ. Endogenous bradykinin and the renin and pressor responses to furosemide in humans. J Pharmacol Exp Ther. 2000 Nov;295(2):644-8.
- Background: PubMed 10972684Brown NJ, Nakamura S, Ma L, Nakamura I, Donnert E, Freeman M, Vaughan DE, Fogo AB. Aldosterone modulates plasminogen activator inhibitor-1 and glomerulosclerosis in vivo. Kidney Int. 2000 Sep;58(3):1219-27. doi: 10.1046/j.1523-1755.2000.00277.x.
- Background: PubMed 10952948Murphey LJ, Gainer JV, Vaughan DE, Brown NJ. Angiotensin-converting enzyme insertion/deletion polymorphism modulates the human in vivo metabolism of bradykinin. Circulation. 2000 Aug 22;102(8):829-32. doi: 10.1161/01.cir.102.8.829.
- Background: PubMed 10871321Murphey LJ, Hachey DL, Oates JA, Morrow JD, Brown NJ. Metabolism of bradykinin In vivo in humans: identification of BK1-5 as a stable plasma peptide metabolite. J Pharmacol Exp Ther. 2000 Jul;294(1):263-9.
- Background: PubMed 11304515Wilsdorf T, Gainer JV, Murphey LJ, Vaughan DE, Brown NJ. Angiotensin-(1-7) does not affect vasodilator or TPA responses to bradykinin in human forearm. Hypertension. 2001 Apr;37(4):1136-40. doi: 10.1161/01.hyp.37.4.1136.
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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.
Nancy Brown
Vanderbilt University
Questions about this trial
What is this clinical trial studying?
An observational study of Cardiovascular Diseases and Heart Diseases, run by Vanderbilt University.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 28 Nov 2016. Status can change between updates, so confirm with the study contact before making plans.
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 NCT00005757, which also lists 9 linked publications.
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 28 Nov 2016.