Blockade of fibronectin-alpha4beta1 adhesive interactions down-regulates cyclooxygenase-2 inducible nitric oxide synthase and prolongs recipient survival in a 24-hour model of cold hepatic ischemia-reperfusion injury.

We investigated the effects of the connecting segment-1 (CS1) peptide, which blocks fibronectin (FN)-alpha4beta1 integrin interactions, upon recipient survival and extent of tissue injury in a well-established rat liver model of ex vivo 24-hour cold ischemia followed by isotransplantation. In this model, CS1 peptides were administered through the portal vein of rat livers prior to and after cold ischemic storage. In addition, recipients of orthotopic liver transplants (OLT) received a dose of CS1 peptides 1 hour post-OLT. CS1 peptide therapy significantly inhibited the intragraft recruitment of T lymphocytes and neutrophil activation/infiltration, and repressed important mediators of inflammation, such as cyclooxygenase-2, and inducible nitric oxide synthase expression. Importantly, CS1 peptide therapy improved function/histological preservation of liver grafts and extended their 14-day survival from 50% in control to 100% in CS1-treated OLTs. Thus, CS1 peptide-mediated blockade of FN-alpha4beta1 interaction protects against severe ischemia-reperfusion injury experienced otherwise by OLTs. These novel findings document the potential of targeting FN-alpha4beta1 in vivo interaction for improving OLT outcomes.