Recombinant P selectin glycoprotein ligand ameliorates chronic ischemia and reperfusion injury after rat intestinal transplantation

Previous studies have demonstrated that the blockade of P selectin through the administration of recombinant P Selectin Glycoprotein Ligand (rPSGL-1Ig) in a model of rat intestinal ischemia and reperfusion injury (IRI) afforded short-term improvement in outcome. The aim of this study was to investigate the long-term consequences of such therapy. IRI was induced in a model of isogeneic intestinal transplantation (ITx) using Lewis rats wherein intestines were procured, cold preserved in lactated Ringer solution for 6 h, and transplanted orthotopically. rPSGL-1Ig (0.4 mg/kg/dose) or saline was administered intravascularly into the intestine prior to storage and into the recipient prior to reperfusion. Separate survival and analysis groups were undertaken. For analysis, animals were sacrificed at day 3, 7, 30, and 100 after ITx. Transplanted ileal tissue was procured and stored for analysis that included histopathology, quantitative cytokine rtPCR, and hemoxygenase-1 (HO-1) and anti-apoptotic (Bcl-2, Bcl-xl) protein expression. Statistical comparison was performed using a Student’s t test. Survival at 100 days was markedly (P < 0.05) improved in the rPSGL-1Ig treated group (90%) versus saline-treated control group (40%). Histopathology was markedly improved at 100 days. At all time points, rtPCR demonstrated significantly (P < 0.05) lower mRNA production in treated animals of the cytokines: TNF-α, IL-6, TGF-β, and β-FGF. Western blot analysis demonstrated increased production of the protective proteins HO-1, Bcl-2, and Bcl-xl with rPSGL-1Ig treatment. Early blockade of P selectin at the time of ITx-associated IRI using rPSGL-1Ig led to significant improvement in survival, reductions in tissue injury on histopathology, reduction in mRNA production for chronic inflammatory cytokines, and increased protection of cellular protective proteins. This data indicate that the control of the early events associated with IRI leads to improvement in long-term isograft inflammatory parameters in a model of rat ITx.