Antithrombotic properties of L-cysteine, N-(mercaptoacetyl)-D-Tyr-Arg-Gly-Asp-sulfoxide (G4120) in a hamster platelet-rich femoral vein thrombosis model.
Platelet aggregation plays an important role in the pathogenesis in arterial thrombotic disorders. The binding of fibrinogen via the Arg-Gly-Asp (RGD) recognition sequence to the platelet glycoprotein IIb/IIIa (GPIIb/IIIa) receptor is an essential step of platelet aggregation induced by various physiologic agonists, and RGD-containing peptides that bind to the GPIIb/IIIa receptor inhibit thrombus formation in vivo. L-cysteine, N-(mercaptoacetyl)D-tyrosyl-L-arginylglycyl-L alpha-aspartyl-cyclic (1----5)-sulfide, 5-oxide (G4120), a cyclic RGD-containing synthetic pentapeptide, inhibits adenosine diphosphate (ADP)-induced platelet aggregation with 50% inhibition (IC50) at a concentration of 0.05 microgram/mL in human plasma, 0.12 microgram/mL in hamster plasma, and 11 micrograms/mL in rat plasma. Corresponding values for the linear tetrapeptide Arg-Gly-Asp-Phe (RGDF) were 7 and 100 micrograms/mL in human and hamster plasma. The antithrombotic effects of G4120 and RGDF were evaluated in a hamster model consisting of a mural platelet-rich femoral vein thrombus induced by standardized endothelial cell damage. Bolus intravenous injection of G4120 was followed by a biphasic disappearance of G4120 from plasma with t1/2 alpha of 3.7 minutes and t1/2 beta of 63 minutes, corresponding to a plasma clearance of 5.2 +/- 0.68 mL/min. Bolus intravenous injection of G4120 inhibited ex vivo platelet aggregation with 0.5 mumol/L ADP and in vivo thrombus formation in a dose-dependent manner, with ID50 of 11 and 11 micrograms/kg, respectively. Bolus injection of RGDF inhibited in vivo thrombus formation; 43% inhibition was obtained at a dose of 30 mg/kg. Thus, this hamster platelet-rich femoral vein thrombosis model may be useful for the investigation of the antithrombotic properties of platelet GPIIb/IIIa antagonistic peptides. The cyclic synthetic peptide G4120 appears to have a very potent antithrombotic activity in vivo.
Imura
Y
Y
Center for Thrombosis and Vascular Research, University of Leuven, Belgium.
Stassen
J M
JM
Bunting
S
S
Stockmans
F
F
Collen
D
D
D000595:Amino Acid Sequence; D000818:Animals; D006224:Cricetinae; D004195:Disease Models, Animal; D004285:Dogs; D005268:Femoral Vein; D005343:Fibrinolytic Agents / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology; D010456:Peptides, Cyclic / Q000493:pharmacokinetics / Q000494:pharmacology*; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010980:Platelet Membrane Glycoproteins / Q000037:antagonists & inhibitors; D051381:Rats; D013454:Sulfoxides / Q000493:pharmacokinetics / Q000494:pharmacology*; D013927:Thrombosis / Q000188:drug therapy
D005343:Fibrinolytic Agents; D009842:Oligopeptides; D010456:Peptides, Cyclic; D010975:Platelet Aggregation Inhibitors; D010980:Platelet Membrane Glycoproteins; D013454:Sulfoxides; C074915:G 4120; C047981:arginyl-glycyl-aspartic acid