P-selectin-dependent inhibition of thrombosis during venous stasis

Leukocyte adhesion, transendothelial migration, and stasis are important co mponents in the pathogenesis of deep vein thrombosis. Anesthetized cats wer e treated with saline, a recombinant soluble form of P-selectin glycoprotei n ligand-1 (rPSGL-Ig), or an E- and L-selectin antibody (EL-246) before exp osure and occlusion of a jugular vein. After 2 or 6 hours of occlusion, jug ular veins were perfused with buffer, fixed, and prepared for scanning elec tron microscopy. In cats receiving saline, 2 and 6 hours of occlusion produ ced moderate levels of leukocyte and platelet adhesion and endothelial cell injury. Treatment of cats with rPSGL-Ig or EL-246 had no apparent effect o n the magnitude of cell adhesion and endothelial cell injury compared with no treatment. After 6 hours of occlusion, the presence of a mural thrombus in untreated veins was observed and confirmed by scanning electron microsco py. Pretreatment of cats with rPSGL-Ig completely (4.0 mg/kg) or partially (1.0 mg/kg) prevented the occurrence of thrombi in the jugular veins. The r eduction in thrombosis by rPSGL-Ig treatment after 6 hours of venous stasis , in the absence of any effect on leukocyte-mediated endothelial cell injur y, suggests an antithrombotic mechanism of action for this protein.