RESUMEN
Leukotriene B(4) (LTB(4)) is a pro-inflammatory mediator that has been implicated in the pathogenesis of a number of diseases including inflammatory bowel disease (IBD) and psoriasis. Since the action of LTA(4) hydrolase is the rate-limiting step for LTB(4) production, this enzyme represents an attractive pharmacological target for the suppression of LTB(4) production. From an in-house screening program, SC-22716 (1, 1-[2-(4-phenylphenoxy)ethyl]pyrrolidine) was identified as a potent inhibitor of LTA(4) hydrolase. Structure-activity relationship (SAR) studies around this structural class resulted in the identification of a number of novel, potent inhibitors of LTA(4) hydrolase, several of which demonstrated good oral activity in a mouse ex vivo whole blood assay.
Asunto(s)
Inhibidores Enzimáticos/síntesis química , Epóxido Hidrolasas/antagonistas & inhibidores , Pirrolidinas/síntesis química , Administración Oral , Animales , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacología , Humanos , Técnicas In Vitro , Leucotrieno B4/biosíntesis , Leucotrieno B4/sangre , Masculino , Ratones , Pirrolidinas/química , Pirrolidinas/farmacología , Relación Estructura-ActividadRESUMEN
Lipoprotein-associated coagulation inhibitor produces feed-back inhibition of tissue factor (tissue thromboplastin)-induced coagulation in the presence of factor Xa Recombinant lipoprotein-associated coagulation inhibitor (rLACI) was tested for its ability to modify thromboplastin-induced intravascular coagulation in a rabbit model that allows monitoring of iodine-125 fibrin accumulation/disappearance in the lung and sampling of blood for the measurement of coagulation parameters. Infusion of thromboplastin into the rabbit caused a rapid increase of radioactivity over the lungs, possibly due to the accumulation of 125I fibrin in the lungs, followed by a rapid decline of radioactivity, suggestive of removal of fibrin from the lungs. Thromboplastin also caused a rapid decrease of systemic fibrinogen that was accompanied by a lengthening of the activated partial thromboplastin time and prothrombin time. The effect of coinfusion of rLACI with thromboplastin or bolus injection of rLACI before thromboplastin infusion was studied. At a high dose of rLACI (800 micrograms/kg body weight), the thromboplastin-induced radioactivity increase in the lungs and the systemic fibrinogen decrease were completely suppressed. The activated partial thromboplastin time and prothrombin time of the plasma samples lengthened, possibly due to the presence of thromboplastin in circulation. The thromboplastin-induced radioactivity increase over the lungs was not completely suppressed by lower doses of rLACI (135 to 270 micrograms/kg body weight), but these doses of rLACI prevented systemic fibrinogen decrease. At a bolus dose of 23 micrograms/kg body weight, rLACI provided 50% protection of the fibrinogen consumption (fibrinogen decreased to 82% compared with 65% in rabbits treated with thromboplastin alone). These results show that rLACI is effective in the inhibition of thromboplastin-induced coagulation in vivo.