title: Preclinical evaluation of S18886 in an experimental model of coronary arterial thrombosis.
abstract: The specific thromboxane receptor antagonist, S18886, was evaluated for prevention of coronary arterial thrombosis and myocardial ischemia-reperfusion in anesthetized canines. For the primary thrombosis study in left circumflex (LCX) coronary artery, 26 dogs were randomized to receive either vehicle (n = 7) or intravenous S18886 (0.3 mg/kg, n = 6; 1.0 mg/kg, n = 6; and 3.0 mg/kg, n = 7). The respective times to occlusion after S18886 were as follows: 56.8 +/- 9.3, 83.5 +/- 14.9, and 92.4 +/- 15.7 minutes compared to 43.3 +/- 8.2 minutes after vehicle. S18886 caused a minimal increase in tongue bleeding time and a significant decrease in ex vivo platelet aggregation to arachidonic acid or U46619. Another 37 dogs were randomized to receive placebo (n = 12), clopidogrel 1.0 mg/kg p.o. QDX3 (n = 9), clopidogrel + S18886 0.3 (n = 9) or 1.0 (n = 7) mg/kg intravenous. Clopidogrel produced a 50% reduction in adenosine diphosphate-induced platelet aggregation and a slight increase in the time to occlusion. However, clopidogrel + S18886 1.0 mg/kg prevented occlusive thrombus formation in most of the coronary vessels over 6 hours. S18886 did not alter myocardial infarct size in the ischemia-reperfusion model. In conclusion, S18886 alone caused a dose-dependent prolongation in the time to primary occlusive coronary artery thrombosis, whereas S18886 + clopidogrel displayed effective in preventing occlusive thrombus formation with only a moderate increase of tongue-bleeding time.
authors.affiliation: Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109-0632, USA. thongz@umich.edu
authors.forename: Ting-Ting
authors.initials: TT
authors.lastname: Hong
authors.forename: Jinbao
authors.initials: J
authors.lastname: Huang
authors.forename: Edward
authors.initials: E
authors.lastname: Driscoll
authors.forename: Benedict R
authors.initials: BR
authors.lastname: Lucchesi
mesh_terms: D000818:Animals; D002341:Carotid Artery Thrombosis / Q000188:drug therapy* / Q000503:physiopathology / Q000517:prevention & control*; D004195:Disease Models, Animal; D004285:Dogs; D004353:Drug Evaluation, Preclinical; D009281:Naphthalenes / Q000494:pharmacology / Q000627:therapeutic use*; D010974:Platelet Aggregation / Q000187:drug effects*; D011422:Propionates / Q000494:pharmacology / Q000627:therapeutic use*; D017482:Receptors, Thromboxane / Q000037:antagonists & inhibitors
chemical_list: D009281:Naphthalenes; D011422:Propionates; D017482:Receptors, Thromboxane; C501362:terutroban