Cyclic RGD Peptides With High Affinity for 51 Integrin Protect Genetically Fat Zucker Rat Livers From Cold Ischemia/Reperfusion Injury C. Fondevila, X.D. Shen, C. Moore, R.W. Busuttil, and A.J. Coito ABSTRACT We tested a hypothesis that interactions between fibronectin (FN), a key extracellular matrix component, and its integrin 51 receptor are important in the development of ischemia/ reperfusion (I/R) injury of steatotic liver transplants. We examined the effect of a cyclic RGD peptide (cRGD), with high affinity for 51 integrin, in a well-established steatotic rat liver model of ex vivo cold ischemia followed by isotransplantation. In this model, cRGD peptides were administered through the portal vein of steatotic Zucker rat livers prior to and after cold ischemic storage. Lean Zucker recipients of fatty orthotopic liver transplants (OLTs) received an additional course of cRGD peptides 1 hour posttransplantation. cRGD peptide therapy significantly inhibited the recruitment of monocyte/macrophages, and repressed the expression of pro-inflammatory cytokines, such as tumor necrosis factor (TNF)- and interferon (IFN)-. Moreover, it resulted in selective inhibition of inducible nitric oxide synthase (iNOS), and MMP-9 expression. Importantly, cRGD peptide therapy improved the function and histologic preservation of steatotic liver grafts, extending their 14-day survival in lean recipients from 50% in untreated to 100% in cRGD-treated OLTs. Thus, cRGD peptide-mediated blockade of FN-51 interaction protects against severe I/R injury otherwise experienced by steatotic OLTs. O RTHOTOPIC LIVER TRANSPLANTATION (OLT) is an effective therapeutic alternative for end-stage liver disease. The critical shortage of human donor livers has provided the rationale to identify methods that allow successful utilization of marginal steatotic grafts. It has not been fully elucidated why transplanted fatty livers exhibit a higher rate of dysfunction and primary nonfunc- tion compared with nonsteatotic OLTs. 1 Ischemia/reper- fusion (I/R) injury suffered by OLTs, associated with leukocyte recruitment at the graft site, is considered to be a major cause of liver dysfunction. 2 Fibronectin (FN), is a key extracellular matrix (ECM) protein, associated with leukocyte adhesion, migration, and activation. 3 Af- ter cold storage and prior to transplantation, 4 FN is upregulated early on the sinusoidal endothelium of stea- totic donor livers. We hypothesized that FN–leukocyte interactions are critical to the steatotic liver I/R injury. The present study examines the significance of FN-51 integrin interactions for recipient survival, liver function, and hepatic preservation in a well-established model of cold ischemia followed by isotransplantation of the stea- totic liver. MATERIAL AND METHODS Animals and Grafting Techniques Fatty livers harvested from genetically obese (fa-/fa-) male Zucker rats (230 to 275 g) were stored for 4 hours at 4°C in University of Wisconsin (UW) solution prior to being transplanted into lean (fa/-) Zucker (260 to 300 g) syngeneic recipients (Harlan Sprague Dawley, Inc., Indianapolis, Ind, USA) following revascularization without hepatic artery reconstruction. 4 Animals were cared for according to guidelines approved by the American Association of Laboratory Animal Care. Treatment With cRGD Peptides Cyclic peptide CRGDGWC peptides (cRGD), which avidly bind the 51 integrin, particularly inhibiting cell attachment to fi- From the Dumont-UCLA Transplant Center, David Geffen School of Medicine at UCLA, Los Angeles, California. Supported by NIH Grant RO1 AI057832, American Association for the Study of Liver Diseases/American Liver Foundation Grant 01114026, and American Heart Association Grant 0030006N. Address reprint requests to Dr A.J. Coito, The Dumont-UCLA Transplant Center, Rm. 77-120 CHS, BOX 957054, Los Angeles, 90095. E-mail: acoito@mednet.ucla.edu © 2005 by Elsevier Inc. All rights reserved. 0041-1345/05/$–see front matter 360 Park Avenue South, New York, NY 10010-1710 doi:10.1016/j.transproceed.2005.04.006 Transplantation Proceedings, 37, 1679 –1681 (2005) 1679