title: P2Y12 gene H2 haplotype is not associated with increased adenosine diphosphate-induced platelet aggregation after initiation of clopidogrel therapy with a high loading dose.
abstract: A large variability in the antiplatelet response to clopidogrel has been consistently reported. Recently, a P2Y12 haplotype was shown to be associated with enhanced adenosine diphosphate (ADP)-induced platelet aggregation in healthy volunteers. The aim of this study was to test in patients (n = 416) scheduled for coronary artery stenting whether P2Y12 haplotype H2 carriage is associated with increased ADP-induced platelet aggregation after administration of a 600 mg loading dose of clopidogrel. Blood was drawn from the arterial sheath at least 2 h after administration of 100 mg aspirin and 600 mg clopidogrel. ADP-induced platelet aggregation was assessed in platelet-rich plasma with light-transmission aggregometry. P2Y12 haplotypes (H1/H2) and P2Y12 C32T genotypes were determined with TaqMan assays. Haplotype combinations and genotypes were not associated with parameters of ADP-induced platelet aggregation after administration of a 600 mg loading dose of clopidogrel. Maximal ADP (5 mumol/l)-induced platelet aggregation was similar in patients carrying haplotype H2 and homozygous carriers of haplotype H1 (43.9 +/- 21.4 versus 43.2 +/- 21.1%, respectively; P = 0.77). Carriage of P2Y12 H2 haplotype does not seem to affect the platelet response to a 600 mg loading dose of clopidogrel in coronary artery disease patients prior to stenting.
authors.affiliation: Deutsches Herzzentrum, Technische Universität München, Lazarettstrasse 36, 80636 Munich, Germany. beckerath@dhm.mhn.de
authors.forename: Nicolas
authors.initials: N
authors.lastname: von Beckerath
authors.forename: Olga
authors.initials: O
authors.lastname: von Beckerath
authors.forename: Werner
authors.initials: W
authors.lastname: Koch
authors.forename: Marianne
authors.initials: M
authors.lastname: Eichinger
authors.forename: Albert
authors.initials: A
authors.lastname: Schömig
authors.forename: Adnan
authors.initials: A
authors.lastname: Kastrati
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology*; D000368:Aged; D001241:Aspirin / Q000008:administration & dosage; D000077144:Clopidogrel; D003327:Coronary Disease / Q000188:drug therapy; D005260:Female; D005838:Genotype; D006239:Haplotypes / Q000235:genetics*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics*; D010974:Platelet Aggregation / Q000187:drug effects* / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D011110:Polymorphism, Genetic; D011956:Receptors, Cell Surface / Q000032:analysis / Q000096:biosynthesis; D018048:Receptors, Purinergic P2 / Q000235:genetics*; D058925:Receptors, Purinergic P2Y12; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000627:therapeutic use
chemical_list: D008565:Membrane Proteins; C548576:P2RY12 protein, human; D010975:Platelet Aggregation Inhibitors; D011956:Receptors, Cell Surface; D018048:Receptors, Purinergic P2; D058925:Receptors, Purinergic P2Y12; D000244:Adenosine Diphosphate; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin