CD62 blockade with P-selectin glycoprotein ligand-immunoglobulin fusion protein reduces ischemia-reperfusion injury after rat intestinal transplantation

Background. Intestinal transplantation (ITx) is severely limited by ischemia-reperfusion (I/R) injury. This study investigates I/R injury and ameliorates its consequences by using a recombinant protein targeted against selectins (recombinant P-selectin glycoprotein ligand-immunoglobulin [rPSGL-Ig]). Methods. An isogeneic model of ITx was undertaken with control animals (no therapy) and treatment animals (rPSGL-Ig). Survival was assessed. Separate groups underwent an analysis examining tissue at multiple time points after I/R injury including histopathology; myeloperoxidase staining; immunostaining for CD3 and ED2; polymerase chain reaction analysis of interleukin (IL)-8/cytokine-inducible neutrophil chemoattractant, IL1β, IL-6, interferon-γ, IL-2, IL-4, and IL 10; and western blots for hemoxygenase-1, BCL-2, and BCL-xl. Standard statistical analysis was undertaken. Results. Treatment with rPSGL-Ig resulted in significantly improved survival after ITx. Analysis demonstrated diminished injury on histopathology and reduced tissue infiltration of neutrophils and lymphocytes. Significant differences in the cytokine profile after ITx were seen between the two groups including the production of inflammatory cytokines at 24 hr and the T_h1 and T _h2 cytokines at 2 and 4 hr. Last, treatment resulted in increased production of hemoxygenase, BCL-2, and BCL-xl. Conclusion. The results of this investigation of I/R injury after ITx revealed that rPSGL-Ig treatment led to marked improvement in outcome. The mechanism of action seems to involve the blockade of neutrophil and lymphocyte infiltration leading to a decreased inflammatory response possibly driven by T_h2 cytokines. The results not only lend insight into the mechanisms behind I/R injury after ITx but also demonstrate a potential therapeutic modality to ameliorate its consequences.