title: Estradiol increases platelet aggregation in Pl(A1/A1) individuals.
abstract: BACKGROUND
  The platelet glycoprotein IIb/IIIa receptor is a key mediator of platelet aggregation and intracoronary thrombosis. Studies have suggested that hormone replacement therapy (HRT) may increase coronary events in postmenopausal women.
  
  
  OBJECTIVE
  We sought to characterize the relationship between the estrogen concentration expected in HRT and platelet aggregation.
  
  
  RESULTS
  Platelet aggregation studies were performed using epinephrine on 30 healthy individuals (15 Pl(A1/A1) and 15 Pl(A1/A2)) before and after incubation with beta-estradiol (E2) (10(-11) mol/L). The effect of E2 10(-11) mol/L on Pl(A1/A1) platelets demonstrated a significant increase (P = .03) in aggregation compared with baseline. In contrast, with the same concentration of E2, aggregation of Pl(A1/A2) platelets decreased significantly compared with baseline (P < .0001).
  
  
  CONCLUSIONS
  Estrogen concentration similar to that expected in HRT resulted in an increase in platelet aggregation in Pl(A1/A1) individuals, but not in Pl(A1/A2) individuals. The data may provide further insight for the increase in coronary events seen in HRT clinical trials and suggest that further evaluation is needed to better define the role of pharmacogenetics in HRT.
authors.affiliation: Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH 43210-1252, USA.
authors.forename: Konstantinos D
authors.initials: KD
authors.lastname: Boudoulas
authors.forename: Christine Roos
authors.initials: CR
authors.lastname: Montague
authors.forename: Pascal J
authors.initials: PJ
authors.lastname: Goldschmidt-Clermont
authors.forename: Glen E
authors.initials: GE
authors.lastname: Cooke
mesh_terms: D000951:Antigens, Neoplasm / Q000502:physiology*; D001792:Blood Platelets / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004837:Epinephrine / Q000494:pharmacology; D004958:Estradiol / Q000235:genetics / Q000494:pharmacology* / Q000502:physiology; D015914:Estrogen Replacement Therapy; D005260:Female; D005838:Genotype; D006801:Humans; D039661:Integrin beta3; D008297:Male; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects* / Q000235:genetics / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D017698:Postmenopause / Q000502:physiology
chemical_list: D000951:Antigens, Neoplasm; C061248:ITGB3 protein, human; D039661:Integrin beta3; D010975:Platelet Aggregation Inhibitors; D004958:Estradiol; D004837:Epinephrine