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Measurement of Platelet Dense Granule Release in Healthy Volunteers

NCT ID: NCT00942617

Last Updated: 2015-12-07

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

WITHDRAWN

Clinical Phase

NA

Study Classification

INTERVENTIONAL

Study Start Date

2009-07-31

Study Completion Date

2012-06-30

Brief Summary

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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

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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

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Platelet Aggregation

Study Design

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Allocation Method

NA

Intervention Model

SINGLE_GROUP

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

NONE

Study Groups

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40 mg non-enteric coated aspirin

40 mg non-enteric coated ASA once daily for 21 + or - 2 days

Group Type EXPERIMENTAL

Aspirin

Intervention Type DRUG

40 mg non-enteric coated ASA once daily for 21 + or - 2 days

Interventions

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Aspirin

40 mg non-enteric coated ASA once daily for 21 + or - 2 days

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* Males over age 18
* Non-smokers
* No chronic medical illness
* No chronic medications

Exclusion Criteria

* 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
* 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.
Minimum Eligible Age

18 Years

Eligible Sex

MALE

Accepts Healthy Volunteers

Yes

Sponsors

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Vanderbilt University

OTHER

Sponsor Role lead

Responsible Party

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John Oates

Professor of Medicine and Pharmacology

Responsibility Role PRINCIPAL_INVESTIGATOR

Principal Investigators

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John A Oates, M.D.

Role: PRINCIPAL_INVESTIGATOR

Vanderbilt University

Locations

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Vanderbilt University

Nashville, Tennessee, United States

Site Status

Countries

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United States

Other Identifiers

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NIH/NHLBI #81009

Identifier Type: -

Identifier Source: secondary_id

IRB# 080895

Identifier Type: -

Identifier Source: org_study_id