RESUMEN

Here, we investigated the anticoagulant effects of darexaban in mice and human plasma in vitro, effects of darexaban in thrombosis and bleeding models in mice, and reversal effects of anti-inhibitor coagulant complex (ACC) and recombinant factor VIIa (rFVIIa) on anticoagulant effects of darexaban. In mice, darexaban inhibited FXa activity in plasma with an ED50 value of 24.8 mg/kg. Both darexaban and warfarin prolonged prothrombin time (PT) at 3 mg/kg and 0.3 mg/kg/day, respectively. PT and activated partial thromboplastin time (aPTT) prolonged by darexaban were dose-dependently reversed by intravenously-administered rFVIIa, significantly so at 1 mg/kg. In a pulmonary thromboembolism (PE) mouse model, both darexaban and warfarin dose-dependently reduced the mortality rate, significantly so at 10 mg/kg and 3 mg/kg/day, respectively. In a FeCl3-induced venous thrombosis (VT) mouse model, darexaban (0.3-10 mg/kg) dose-dependently decreased the thrombus protein content, significantly so at doses of 3 mg/kg or higher. In a tail-transection mouse model, darexaban had no significant effect on the amount of blood loss at doses up to 10 mg/kg, while warfarin showed a dose-dependent increase in blood loss, significantly so from 1 mg/kg/day. Darexaban and its metabolite darexaban glucuronide significantly prolonged PT and aPTT in human plasma in vitro, and while rFVIIa concentration-dependently reversed the prolonged PT in this plasma, ACC dose-dependently reversed both PT and aPTT changes prolonged by darexaban. Taken together, these results suggest that darexaban has a potential to be an oral anticoagulant with a better safety profile than warfarin, and that rFVIIa and ACC may be useful as antidotes to darexaban in cases of overdose.

Asunto(s)

Anticoagulantes/farmacología , Azepinas/farmacología , Benzamidas/farmacología , Hemorragia/tratamiento farmacológico , Trombosis/tratamiento farmacológico , Warfarina/uso terapéutico , Animales , Anticoagulantes/efectos adversos , Azepinas/efectos adversos , Benzamidas/efectos adversos , Modelos Animales de Enfermedad , Factor VIIa/farmacología , Hemorragia/sangre , Humanos , Masculino , Ratones , Ratones Endogámicos ICR , Tiempo de Tromboplastina Parcial , Tiempo de Protrombina , Proteínas Recombinantes/farmacología , Trombosis/sangre , Warfarina/efectos adversos , Warfarina/farmacología

RESUMEN

The oral direct factor Xa inhibitor darexaban administered intraduodenally prevented venous thrombus formation in both rats and rabbits with no effect on bleeding. The indirect parenteral Factor Xa inhibitor fondaparinux exerted similar properties, only prolonging bleeding time at extremely high doses. In contrast, the thrombin inhibitor ximelagatran and low-molecular-weight heparin enoxaparin prolonged bleeding time at antithrombotic doses. Studies using human platelets showed darexaban glucuronide, a darexaban metabolite that predominantly determines darexaban antithrombotic effects in vivo, had no effect on platelet activation and aggregation, while heparin and enoxaparin activated platelets. Melagatran, heparin, and enoxaparin all inhibited thrombin-induced platelet aggregation at clinically relevant concentrations. Taken together, these results suggest that thrombin-inhibiting drugs may increase the risk of bleeding, while darexaban may have potential as an orally available antithrombotic agent with a wide therapeutic window.

Asunto(s)

Anticoagulantes/farmacología , Azepinas/farmacología , Benzamidas/farmacología , Inhibidores del Factor Xa , Trombosis de la Vena/tratamiento farmacológico , Animales , Anticoagulantes/administración & dosificación , Anticoagulantes/toxicidad , Antitrombinas/administración & dosificación , Antitrombinas/farmacología , Antitrombinas/toxicidad , Azepinas/administración & dosificación , Azepinas/toxicidad , Benzamidas/administración & dosificación , Benzamidas/toxicidad , Plaquetas/efectos de los fármacos , Plaquetas/metabolismo , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Glucurónidos/farmacología , Hemorragia/inducido químicamente , Humanos , Masculino , Conejos , Ratas , Ratas Sprague-Dawley , Especificidad de la Especie , Trombosis de la Vena/patología

Asunto(s)

Subunidades alfa de la Proteína de Unión al GTP Gq-G11/antagonistas & inhibidores , Péptidos Cíclicos/farmacología , Animales , Arteriopatías Oclusivas/tratamiento farmacológico , Arteriosclerosis/tratamiento farmacológico , Plaquetas/efectos de los fármacos , Fibrinolíticos/farmacología , Técnicas In Vitro , Ratones , Ratas

RESUMEN

The protective effect of YM-254890, a specific Galphaq/11 inhibitor, on laurate-induced peripheral arterial disease in rats was compared with those of prostaglandin E1 (PGE1), beraprost, and clopidogrel. YM-254890 inhibited ADP-induced ex vivo rat platelet aggregation at a dose of 3 microg/kg. Furthermore, YM-254890 strongly inhibited phenylephrine-, serotonin- and endothelin-1-induced contractions in the rat aorta, and improved dermal blood flow after the laurate injection. The intra-arterial single bolus administration of YM-254890 15 min after the laurate injection dose-dependently inhibited the progression of the lesion, with significance, at 3 microg/kg without affecting systemic blood pressure. PGE1 and beraprost, when administered before the laurate injection, were effective, but their potencies were less than that of YM-254890. Clopidogrel significantly suppressed lesion progression when administered at 30 mg/kg twice a day for 3 days, which completely inhibited platelet aggregation. These results suggest that the local administration of YM-254890 may be useful for treating peripheral arterial disease.

Asunto(s)

Subunidades alfa de la Proteína de Unión al GTP Gq-G11/antagonistas & inhibidores , Péptidos Cíclicos/farmacología , Enfermedades Vasculares Periféricas/prevención & control , Animales , Aorta/efectos de los fármacos , Aorta/fisiología , Velocidad del Flujo Sanguíneo/efectos de los fármacos , Presión Sanguínea/efectos de los fármacos , Clopidogrel , Dermis/irrigación sanguínea , Dermis/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Endotelio Vascular/fisiología , Epoprostenol/análogos & derivados , Epoprostenol/farmacología , Frecuencia Cardíaca/efectos de los fármacos , Miembro Posterior/irrigación sanguínea , Miembro Posterior/efectos de los fármacos , Técnicas In Vitro , Ácidos Láuricos , Masculino , Enfermedades Vasculares Periféricas/inducido químicamente , Enfermedades Vasculares Periféricas/patología , Agregación Plaquetaria/efectos de los fármacos , Inhibidores de Agregación Plaquetaria/farmacología , Ratas , Ratas Sprague-Dawley , Ticlopidina/análogos & derivados , Ticlopidina/farmacología , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacología

RESUMEN

1 The effects of YM-254890, a specific Galpha(q/11) inhibitor, on platelet functions, thrombus formation under high-shear rate condition and femoral artery thrombosis in cynomolgus monkeys were investigated. 2 YM-254890 concentration dependently inhibited ADP-induced intracellular Ca(2+) elevation, with an IC(50) value of 0.92+/-0.28 microM. 3 P-selectin expression induced by ADP or thrombin receptor agonist peptide (TRAP) was strongly inhibited by YM-254890, with IC(50) values of 0.51+/-0.02 and 0.16+/-0.08 microM, respectively. 4 YM-254890 had no effect on the binding of fibrinogen to purified GPIIb/IIIa, but strongly inhibited binding to TRAP-stimulated washed platelets. 5 YM-254890 completely inhibited platelet shape change induced by ADP, but not that induced by collagen, TRAP, arachidonic acid, U46619 or A23187. 6 YM-254890 attenuated ADP-, collagen-, TRAP-, arachidonic acid- and U46619-induced platelet aggregation with IC(50) values of <1 microM, whereas it had no effect on phorbol 12-myristate 13-acetate-, ristocetin-, thapsigargin- or A23187-induced platelet aggregation. 7 High-shear stress-induced platelet aggregation and platelet-rich thrombus formation on a collagen surface under high-shear flow conditions were concentration dependently inhibited by YM-254890. 8 The antithrombotic effect of YM-254890 was evaluated in a model of cyclic flow reductions in the femoral artery of cynomolgus monkeys. The intravenous bolus injection of YM-254890 dose dependently inhibited recurrent thrombosis without affecting systemic blood pressure or prolonging template bleeding time. 9 YM-254890 is a useful tool for investigating Galpha(q/11)-coupled receptor signaling and the physiological roles of Galpha(q/11).

Asunto(s)

Plaquetas/efectos de los fármacos , Arteria Femoral/efectos de los fármacos , Fibrinolíticos/farmacología , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/antagonistas & inhibidores , Péptidos Cíclicos/farmacología , Inhibidores de Agregación Plaquetaria/farmacología , Trombosis/prevención & control , Adenosina Difosfato , Animales , Plaquetas/citología , Plaquetas/metabolismo , Calcio/metabolismo , Forma de la Célula , Modelos Animales de Enfermedad , Relación Dosis-Respuesta a Droga , Femenino , Arteria Femoral/fisiopatología , Arteria Femoral/cirugía , Fibrinógeno/metabolismo , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/metabolismo , Ligadura , Macaca fascicularis , Selectina-P/metabolismo , Agregación Plaquetaria , Receptores de Trombina , Flujo Sanguíneo Regional , Estrés Mecánico , Trombosis/metabolismo , Trombosis/fisiopatología

RESUMEN

The pharmacological properties of YM-254890, a specific G(alpha)q/11 inhibitor, on acute thrombosis and chronic neointima formation after vascular injury have been investigated. FeCl3 was used to induce vascular injury in the carotid artery of mice. For the thrombosis studies, the test drug was either intravenously or orally administered before vascular injury. For the neointima studies, the test drug was orally administered 1 h before and twice daily for 1 week after vascular injury. Histological analysis was then performed 3 weeks later. YM-254890 significantly inhibited ex vivo platelet aggregation 5 min after intravenous bolus injection at 0.03 mg/kg or more, and 1 h after oral administration at 1 mg/kg. YM-254890 significantly inhibited thrombus formation after intravenous bolus injection at 0.03 mg/kg as well as after oral administration at 1 mg/kg, but tail transection bleeding time was significantly prolonged at 0.1 mg/kg for intravenous injection and 3 mg/kg for oral administration. Furthermore, oral administration of YM-254890 dose-dependently inhibited neointima formation 3 weeks after vascular injury with significant effects at 1 mg/kg twice daily for 1 week. Clopidogrel also significantly inhibited neointima formation at its antithrombotic dose, but its inhibitory potency was less than that of YM-254890. However, YM-254890 significantly reduced systemic blood pressure at doses 3 times higher than those that produced significant inhibitory effects on thrombosis and neointima formation. Though the systemic use of YM-254890 may be limited, owing to its narrow therapeutic window, this unique compound is a useful research tool for investigating the physiological roles of G(alpha)q/11 .

Asunto(s)

Inhibidores Enzimáticos/farmacología , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/antagonistas & inhibidores , Péptidos Cíclicos/farmacología , Trombosis/tratamiento farmacológico , Administración Oral , Animales , Presión Sanguínea , Arterias Carótidas/patología , Proliferación Celular , Cloruros , Cromonas/farmacología , Clopidogrel , Relación Dosis-Respuesta a Droga , Compuestos Férricos/farmacología , Frecuencia Cardíaca , Masculino , Ratones , Ratones Endogámicos ICR , Modelos Químicos , Morfolinas/farmacología , Músculo Liso/citología , Músculo Liso Vascular/patología , Agregación Plaquetaria , Trombosis/patología , Ticlopidina/análogos & derivados , Ticlopidina/farmacología , Factores de Tiempo , Túnica Íntima/patología

RESUMEN

Factor Xa (fXa) is a serine protease, which plays a pivotal role in the coagulation cascade. To improve the oral anticoagulant activity of fXa inhibitors containing a 1,4-diazepane moiety as the P4 part, a prodrug strategy was examined. Among the compounds evaluated in this study, amidoxime prodrugs bearing an ester moiety, such as compounds 21 and 30, showed effective oral anticoagulant activity in mice.

Asunto(s)

Amidinas/síntesis química , Amidinas/farmacología , Anticoagulantes/síntesis química , Anticoagulantes/farmacología , Antitrombina III/química , Profármacos/síntesis química , Profármacos/farmacología , Administración Oral , Amidinas/química , Animales , Anticoagulantes/química , Antitrombina III/síntesis química , Antitrombina III/farmacología , Compuestos Aza/síntesis química , Compuestos Aza/química , Compuestos Aza/farmacología , Pruebas de Coagulación Sanguínea , Femenino , Humanos , Ratones , Embarazo