P-Selectin Monoclonal Antibody May Attenuate the Whole Body Inflammatory Response Induced by Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) is known to induce an inflammatory response in association with neutrophil mediated lung injury. P-Selectin has been reported to be involved in the initiation of this inflammatory response by promoting the adhesion of neutrophils to endothelial cells in postcapillary venules. However, the role of P-selectin in the inflammatory response induced by CPB has never been clarified. To elucidate its role, we evaluated the effect of an anti-rat specific P-selectin monoclonal antibody (ARP2-4; Sumitomo Pharmaceutical) on the response of inflammatory cytokines and lung injury in a rat-CPB model. Twenty Sprague-Dawley rats underwent CPB for 30 minutes (80 ml/kg per minute, 34 degrees C) under one of two conditions. In group P, ARP2-4 (3 mg/kg) was added to the priming solution of the bypass circuit (n = 10). Saline alone was given to group C (n = 10). Inflammatory cytokines (tumor necrosis factor-alpha [TNF-alpha], interleukin[IL]-1beta, IL-6, and IL-8) and respiratory index (RI) as a marker of pulmonary gas-exchange ability were measured 1) before the initiation of CPB, 2) at the termination of CPB, and 3) 2 hours after the termination of CPB. Neither TNF-alpha nor IL-1beta was detected during the experimental period in either group. The plasma levels of IL-6 and IL-8 increased after CPB in both groups, but they were significantly lower in group P than in group C. The RI value increased in a pattern similar to that of the inflammatory cytokines and was significantly lower in group P. These data demonstrate that the addition of an anti-rat specific monoclonal antibody inhibits the abnormal release of inflammatory cytokines and attenuates CPB induced lung injury in rats. Thus, P-selectin may play a role in the augmentation of CPB induced inflammatory response, and the use of its inhibitory monoclonal antibody seems to be a promising strategy for the treatment of CPB induced lung injury.