Clinical trial NCT01576536: Genetic Variation in Platelet Aggregation
Official title: Genetic Variation in Platelet Aggregation
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Myocardial Infarction
Keywords: Myocardial infarction
Platelet aggregation
cold pressor test
Genetics
Lead sponsor: Vanderbilt University Medical Center
Sponsor class: OTHER
First posted: 2012-04-12
Enrollment: 117
Sex: ALL
Minimum age (years): 18
Maximum age (years): 45
Standard ages: ADULT
Accepts healthy volunteers: yes
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Healthy subjects will be recruited by advertisement and word-of-mouth.

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.

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 alpha 2a-adrenergic receptor (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. If there are no differences among haplotypes, then the haplotypes will be combined to analyze.

Eligibility criteria: 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.

Primary outcomes:
measure: LogEC50 Platelet Aggregation
timeFrame: at 6am and 930am
Secondary outcomes:
measure: Percentage, Adenosine Diphosphate (ADP) Induced Platelet Aggregation
timeFrame: at 6am and 930am
measure: Percentage, Collagen Induced Platelet Aggregation
timeFrame: at 6am and 930am
Other outcomes:
Locations:
city: Nashville
country: United States
facility: the Vanderbilt University General Clinical Research Center
state: Tennessee
Study officials:
affiliation: Vanderbilt University Medical Center
name: Michael Stein, MBChB
role: PRINCIPAL_INVESTIGATOR
References: