Platelet AggregationNCT00942617
Measurement of Platelet Dense Granule Release in Healthy Volunteers
A study testing Aspirin in people with Platelet Aggregation, run by Vanderbilt University at 1 site in United States.
Trial summary
Aspirin has been shown to reduce cardiovascular events in at risk individuals. Elucidation of mechanisms of aspirin resistance and a possible loss of effect of aspirin over time with chronic aspirin treatment necessitate a more precise method of measuring the "release phase" of platelet activation, including the… Read more about this study
- Who is it for?
- Ages 18 years and older, men onlyHealthy volunteers can take part
- Conditions the study is for
- Platelet Aggregation
- What is being tested?
- Aspirin
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 0 participants
- Where
- 1 siteUnited States
- Study dates
- Jul 2009to Jun 2012
- Phase
- Interventional
- 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 18 years and older
- Men only
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Males over age 18
- Non-smokers
- No chronic medical illness
- No chronic medications
Who cannot join
- ASA/NSAID use previous 14 days.
- History of chronic NSAID use.
- Currently taking NSAIDs, opioid analgesics, corticosteroids, or anticoagulants.
- History of coronary artery disease, myocardial infarction, coronary artery bypass grafting, percutaneous angioplasty, diabetes mellitus or stroke.
- History of hypertension
- BMI >35
Show all 14Show fewer
- Smokers
- History of gastric, duodenal, or esophageal ulcers or serious gastrointestinal bleed.
- History of frequent headaches, pain syndrome, or other condition requiring frequent use of analgesics.
- History of adverse reaction to ASA.
- Initial platelet count <100K/µl or >500K/µl.
- Initial hematocrit <35% or >50%.
- Weight less than 110 pounds.
- Female subjects will be excluded to avoid possible confounding uterine smooth muscle production of prostaglandins which various throughout the menstrual cycle.
Trial locations and contacts
1 site in 1 country.
About this study
Aspirin has been shown to reduce cardiovascular events in at risk individuals. Elucidation of mechanisms of aspirin resistance and a possible loss of effect of aspirin over time with chronic aspirin treatment necessitate a more precise method of measuring the "release phase" of platelet activation, including the release of dense granules from platelets.
Read the detailed description
This is a proposal for a pilot study to evaluate the feasibility of measuring 5-hydroxytryptamine (5-HT) release from platelets as an indicator of dense granule release during platelet activation in volunteers taking aspirin.
One phase of platelet response to activating agonists involves release of dense granules, which are known to contain 5HT (serotonin) and ATP. There are various methods of measuring the degranulation of platelets: ATP release can be measured using a lumiaggregometer, and release of 14C radiolabeled 5-HT from platelets. Using the aggregometer and a 14C labeled 5-HT assay can be used to measure 5-HT release from platelets.
Our experience suggests that ADP-induced ATP release is insensitive to detect very low levels of platelet dense granule release, which occurs in aspirin-treated subjects. The pilot study will permit optimizing the method for reliably detecting low levels of 5HT release in patients who achieve submaximal inhibition of the cyclooxygenase during aspirin treatment.
- Conditions
- Platelet Aggregation
- Being tested
- Aspirin
- Keywords
- platelet aggregation, granule secretion, thromboxane production, cyclooxygenase-1, ATP release, aspirin resistance, platelet activation, flow cytometry, Platelet aggregation in healthy volunteers
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AspirinDrug
40 mg non-enteric coated ASA once daily for 21 + or - 2 days
| Study group | Role | What they receive |
|---|---|---|
| 40 mg non-enteric coated aspirin | Experimental | 40 mg non-enteric coated ASA once daily for 21 + or - 2 days Receives: Drug: Aspirin |
What is being measured
The primary outcome is the main question the study is designed to answer.
The primary measurement will be platelet 5-HT release induced by ADP after 1 and 2 weeks administration of daily ASA.
Measured: 3 weeks
Secondary outcomes (1)
Measurements will include platelet COX-1 activity, flow cytometric measurement of markers of platelet activation, platelet aggregation and ATP release, and serum thromboxane B2 (TxB2) levels, at each timepoint.
Measured: 3 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted21 Jul 2009 (estimated)
- Study startJul 2009
- Primary completionJun 2012
- Study completionJun 2012
Why it stopped: funding issue
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Platelet AggregationStudies 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
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Vanderbilt University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, John Oates, Vanderbilt University
- Investigators
- John A Oates, M.D., Principal investigator, Vanderbilt University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT00942617
- Sponsor's protocol ID
- IRB# 080895
- Other IDs
- NIH/NHLBI #81009
- Status last verified
- Dec 2015
- First submitted
- 17 Jul 2009
- Last updated
- 7 Dec 2015
- Results posted
- No
- Data monitoring committee
- No
Study at a glance
From the registry record, last updated by the sponsor on 7 Dec 2015. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Measurement of Platelet Dense Granule Release in Healthy Volunteers
- ClinicalTrials.gov ID
- NCT00942617
- Acronym / sponsor ID
- IRB# 080895
- Conditions
- Platelet Aggregation
- Keywords
- platelet aggregation, granule secretion, thromboxane production, cyclooxygenase-1, ATP release, aspirin resistance, platelet activation, flow cytometry
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: funding issue
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Vanderbilt UniversityUniversity, hospital or other
- Study start
- Jul 2009
- Primary completion
- Jun 2012 (actual)
- Study completion
- Jun 2012 (actual)
- First posted
- 21 Jul 2009 (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.
Aspirin has been shown to reduce cardiovascular events in at risk individuals. Elucidation of mechanisms of aspirin resistance and a possible loss of effect of aspirin over time with chronic aspirin treatment necessitate a more precise method of measuring the "release phase" of platelet activation, including the release of dense granules from platelets.
Detailed description
This is a proposal for a pilot study to evaluate the feasibility of measuring 5-hydroxytryptamine (5-HT) release from platelets as an indicator of dense granule release during platelet activation in volunteers taking aspirin.
One phase of platelet response to activating agonists involves release of dense granules, which are known to contain 5HT (serotonin) and ATP. There are various methods of measuring the degranulation of platelets: ATP release can be measured using a lumiaggregometer, and release of 14C radiolabeled 5-HT from platelets. Using the aggregometer and a 14C labeled 5-HT assay can be used to measure 5-HT release from platelets.
Our experience suggests that ADP-induced ATP release is insensitive to detect very low levels of platelet dense granule release, which occurs in aspirin-treated subjects. The pilot study will permit optimizing the method for reliably detecting low levels of 5HT release in patients who achieve submaximal inhibition of the cyclooxygenase during aspirin treatment.
Study design
- Primary purpose
- Basic science
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| 40 mg non-enteric coated aspirin | Experimental | Drug: Aspirin40 mg non-enteric coated ASA once daily for 21 + or - 2 days |
Who may qualify
- Ages
- 18 years and older
- Sex
- Male only
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Males over age 18
- Non-smokers
- No chronic medical illness
- No chronic medications
Key exclusion criteria (14 listed)
- ASA/NSAID use previous 14 days.
- History of chronic NSAID use.
- Currently taking NSAIDs, opioid analgesics, corticosteroids, or anticoagulants.
- History of coronary artery disease, myocardial infarction, coronary artery bypass grafting, percutaneous angioplasty, diabetes mellitus or stroke.
- History of hypertension
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Aspirin40 mg non-enteric coated ASA once daily for 21 + or - 2 days | Drug | 40 mg non-enteric coated aspirin |
Primary outcome
The primary measurement will be platelet 5-HT release induced by ADP after 1 and 2 weeks administration of daily ASA.
Time frame: 3 weeks
1 secondary outcome
Measurements will include platelet COX-1 activity, flow cytometric measurement of markers of platelet activation, platelet aggregation and ATP release, and serum thromboxane B2 (TxB2) levels, at each timepoint.
Time frame: 3 weeks
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 7 Dec 2015.
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Cookies for Platelets
Blood Donation
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.
John A Oates, M.D. principal investigator
Vanderbilt University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing Aspirin in people with Platelet Aggregation, run by Vanderbilt University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 14 exclusion criteria. 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: withdrawn, as of the sponsor's last update on 7 Dec 2015. 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 was withdrawn before enrolling participants, so there are no results.
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.
What does the primary outcome measure?
The primary measurement will be platelet 5-HT release induced by ADP after 1 and 2 weeks administration of daily ASA. (time frame: 3 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
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 7 Dec 2015.