Genetic Variation in Platelet Aggregation

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01576536
Recruitment Status : Active, not recruiting
First Posted : April 12, 2012
Last Update Posted : January 25, 2018
Information provided by (Responsible Party):
C. Michael Stein, Vanderbilt University

Brief Summary:
The aim of the study is to test whether genetic variation in the alpha 2A adrenergic receptor affects diurnal variation in platelet aggregation.

Condition or disease
Myocardial Infarction

Detailed Description:
There is a marked diurnal fluctuation in the occurrence of acute myocardial infarction and sudden death, with peak incidences occurring in the early morning. Platelet aggregation has also been shown to increase in the early morning. The investigators will test the hypothesis that ADRA2A genetic variation, specifically haplotype 4, affects platelet aggregation. The investigators will compare diurnal platelet aggregation in haplotype 4 subjects with subjects in the other haplotype families. In addition, the investigators will compare platelet aggregation after the cold pressor test in haplotype 4 with the other haplotype families.

Study Type : Observational
Actual Enrollment : 118 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Genetic Variation in Platelet Aggregation
Study Start Date : July 2012
Estimated Primary Completion Date : December 2018
Estimated Study Completion Date : December 2018

Healthy volunteers
Normal healthy volunteers

Primary Outcome Measures :
  1. percentage platelet aggregation [ Time Frame: Within 120minutes of sample collection ]
    We will compare the percentage platelet aggregation to 2µM epinephrine between haplotype 4 family participants and other haplotype families

Secondary Outcome Measures :
  1. Percentage platelet aggregation to collagen and ADP [ Time Frame: within 120 minutes of sample collection ]
    We will compare the percentage platelet aggregation to collagen and ADP between haplotype 4 participant and other haplotype families.

  2. Percentage platelet aggregation after cold pressor test [ Time Frame: within 120 minutes of sample collection ]
    We will compare percentage platelet aggregation of different agonist after cold pressor test between haplotype 4 participants and other haplotype families.

Biospecimen Retention:   Samples With DNA
Blood samples for DNA and plasma/serum for subsequent biomarker analysis if required.

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Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Healthy subjects will be recruited by advertisement and word-of-mouth.

Inclusion Criteria:

  • Men and women aged 18 - 45 years inclusive.
  • Women of the above age will be studied between day 1 and day 14 of a normal menstrual cycle.
  • Subjects must be willing to give informed consent for the study and able to adhere to the study diet and study procedures.
  • Subjects and immediate extended family up till grandparents will be Caucasians or African Americans only.
  • Subjects will be free of any clinically significant disease.
  • Clinical laboratory test (CBC, blood chemistry) will be within acceptable limits.

Exclusion Criteria:

  • Subjects who have taken any antiplatelet, anticoagulant or procoagulant medicines within the last three weeks preceding the study.
  • Subjects who have taken medications (including over the counter medications) other than oral contraceptives in the past two weeks.
  • Subjects who smoke or have smoked in the past 3 months.
  • Subjects who are presently or were formerly a narcotic addict or alcoholic.
  • Females with a positive pregnancy test.
  • Females who are breast feeding.

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 identifier (NCT number): NCT01576536

United States, Tennessee
the Vanderbilt University General Clinical Research Center
Nashville, Tennessee, United States, 37232
Sponsors and Collaborators
Vanderbilt University
Principal Investigator: Michael Stein, MBChB Vanderbilt University Medical Center

Responsible Party: C. Michael Stein, Dan May Professor of Medicine and Pharmacology, Vanderbilt University Identifier: NCT01576536     History of Changes
Other Study ID Numbers: 111760
First Posted: April 12, 2012    Key Record Dates
Last Update Posted: January 25, 2018
Last Verified: January 2018

Keywords provided by C. Michael Stein, Vanderbilt University:
Myocardial infarction
Platelet aggregation
cold pressor test

Additional relevant MeSH terms:
Myocardial Infarction
Pathologic Processes
Myocardial Ischemia
Heart Diseases
Cardiovascular Diseases
Vascular Diseases