Cytoprotective Effects of a Cyclic RGD Peptide in Steatotic Liver Cold Ischemia and Reperfusion Injury

Abstract

The serious need for expanding the donor population has attracted attention to the use of steatotic donor livers in orthotopic liver transplantation (OLT). However, steatotic livers are highly susceptible to hepatic ischemia-reperfusion injury (IRI). Expression of fibronectin (FN) by endothelial cells is an important feature of hepatic response to injury. We report the effect of a cyclic RGD peptide with high affinity for the a 5b 1, the FN integrin receptor, in a rat model of steatotic liver cold ischemia, followed by transplantation. RGD peptide therapy ameliorated steatotic IRI and improved the recipient survival rate. It significantly inhibited the recruitment of monocyte/macrophages and neutrophils, and depressed the expression of proinflammatory mediators, such as inducible nitric oxide synthase (iNOS) and interferon (IFN)-c . Moreover, it resulted in profound inhibition of metalloproteinase-9 (MMP-9) expression, a gelatinase implied in leukocyte migration in damaged livers. Finally, we show that RGD peptide therapy reduced the expression of the 17-kDa active caspase-3 and the number of apoptotic cells in steatotic OLTs. The observed protection against steatotic liver IRI by the cyclic RGD peptides with high affinity for the a 5b 1 integrin suggests that this integrin is a potential therapeutic target to allow the successful utilization of marginal steatotic livers in transplantation. 2). IRI is a multifactorial antigen-independent inflammatory process that can lead to graft loss, particularly with marginal donor organs (2,3). Indeed, a growing body of evidence shows that IRI is poorly tolerated in fatty livers (4-6). The migration of leukocytes is a key event in acute inflammatory liver injury (7). The transmigration of these cells across endothelial and extracellular matrix (ECM) protein barriers is dependent on a cascade of adhesion and focal matrix degradation events (8). FN is a large glycoprotein with a central role in cellular adhesion and migration. The very early expression of the 'so-called' cellular FN by sinusoidal endothelial cells is a prominent feature of hepatic response to injury (9), including IRI in steatotic livers (10). The role of FN in leukocyte adhesion, migration and activation has been extensively reported (11). FN has been implicated in multiple pathological conditions, including tumor metastasis (12), rheumatoid arthritis (13), cardiac allograft rejection (14), liver fibrosis (9) and liver IRI (10

Cyclic arginine-glycine-aspartate attenuates acute lung injury in mice after intestinal ischemia/reperfusion

“…In addition, cyclic RGD at 4 mg/kg BW had been applied in the study of steatotic liver cold ischemia and reperfusion injury [30]. We also performed a pilot study at a dose of 10 mg/kg BW cRGD, but did not observe a noticeable difference in comparison with the 5 mg/kg BW dose.…”

Therapeutic Sesamol Attenuates Monocrotaline-Induced Sinusoidal Obstruction Syndrome in Rats by Inhibiting Matrix Metalloproteinase-9

“…We conclude that the mechanism used by sesamol to reduce tissue injury is inhibiting the recruitment of inflammatory cells as well as inhibiting the expression and activity of MMP-9, thereby attenuating the breakdown of the cytoskeleton proteins of hepatocytes after the onset of SOS. During SOS, sinusoidal endothelial cells [9] and recruited inflammatory cells [6,[14][15][16] become inflamed and release active MMP-9.…”

“…Monocrotaline-induced SOS is characterized by elevated levels of aspartate transaminase (AST), alanine transaminase (ALT), and hepatic injury with steatosis [4], recruitment of mast cells [5], CD 68 ? Kupffer cells [6], neutrophils [7], myeloperoxidase (MPO) activity [8], matrix metalloproteinase-9 (MMP-9) activity and expression [9], and decreased tissue inhibitor of matrix metalloproteinase-1 (TIMP-1) expression [10,11]. The late phase (48 h) of SOS is characterized by the recruitment of inflammatory cells that release active MMP-9 [6,[12][13][14][15][16], which ultimately breaks the extracellular matrix proteins laminin and collagen in rats [9,17].…”

Leukocyte transmigration across endothelial and extracellular matrix protein barriers in liver ischemia/reperfusion injury

“…There is a growing body of evidence supporting the view that cell attachment to ECM proteins and subsequent degradation are related events. Indeed, studies from our laboratory have shown that fibronectin interactions with its two α4β1 and α5β1 integrin receptors, expressed on leukocytes, are capable of regulating MMP-9 expression by leukocytes in hepatic IRI [68;101*]. Others have demonstrated that MMP-9 activation involves nitric oxide (NO)-mediated metalloproteinase S-nitrosylation S [86].…”