Anti-P-selectin antibody decreases inflammation and thrombus formation in venous thrombosis

Purpose: Venous thrombosis and inflammation are interrelated. P-selectin contributes to activation of leukocyte-mediated inflammation. Therefore, we hypothesized that the neutralization of P-selectin mould decrease vein wall inflammation and thrombosis. Methods: Twelve baboons underwent infrarenal inferior vena caval balloon occlusion to induce thrombosis. Two groups of four baboons received neutralizing intravenous anti-P-selectin antibody (PSab) GA6 or CY1748 before occlusion and at days 2 and 4. Four baboons received saline control injections. One baboon per group was killed at days 2, 6, and 13, and at 2 months. Analysis included phlebography, ultrasound, gadolinium (Gd)-enhanced magnetic resonance venography (reflecting vein wall inflammation), and histologic, morphometric, and protein evaluation of the vein wall. Thrombus presence or absence was assessed. Results: By day 2 in PSab baboons, vein wall Gd enhancement was decreased in the mid-inferior vena cava and the right iliac vein (P < 0.05; GA6 vs control baboons), normalizing by 2 months. The mid-inferior vena cava revealed fewer neutrophils and total leukocytes in PSab baboons; however, for GA6 in the right iliac vein these decreases were not present despite the absence of Gd enhancement; they were decreased with CY1748. PSab baboons demonstrated significantly less thrombus than control baboons (p < 0.01, GA6 and CY1748 vs control baboons). Conclusions: Anti-P-selectin antibody decreases vein wall inflammation and thrombus formation. Inhibition of P-selectin may be useful in venous thrombosis prophylaxis.