Human hepatocellular carcinoma (HCC) has a high rate of tumor recurrence and metastasis, resulting in shortened survival times. The efficacy of current systemic therapies for HCC is limited. In this study, we used xenograft tumor models to investigate the use of antibodies that block CD47 and inhibit HCC tumor growth. Immunostaining of tumor tissue and HCC cell lines demonstrated CD47 over-expression in HCC as compared to normal hepatocytes. Macrophage phagocytosis of HCC cells was increased after treatment with CD47 antibodies (CD47mAbs) that block CD47 binding to SIRPα. Further, CD47 blockade inhibited tumor growth in both heterotopic and orthotopic models of HCC, and promoted the migration of macrophages into the tumor mass. Our results demonstrate that targeting CD47 by specific antibodies has potential immunotherapeutic efficacy in human HCC.

UW solution and HTK solution are both used for cold preservation of liver allografts. Although they are about equally effective, their compositions are very different, and they were formulated using different rationales. The authors recently showed an important role for MMPs in liver preservation injury and consequently postulated that these preservation solutions contain cryptic inhibitors of MMP activity. To determine this possibility, the ability of these solutions to inhibit MMP activity was studied. The source of MMP2 and MMP9 was human liver effluents obtained at the time of liver transplantation or commercially available human recombinant MMP2 and MMP9. MMP2 and MMP9 showed gelatinolytic activity at 37ЊC and also at 4ЊC, although activity at 4ЊC was reduced. Activity was inhibited by University of Wisconsin (UW) and Histidine/Tryptophan/ Ketoglutarate (HTK) solutions. Examination of individual ingredients disclosed that reduced glutathione (GSH) and lactobionate in UW solution and histidine in HTK solution were the cryptic inhibitors. HTK solution was a more effective inhibitor than UW solution. GSH inhibited the activity of both enzymes, but was a much more effective inhibitor of MMP9 than MMP2. Oxidized glutathione(GSSG) was a much less effective inhibitor of the enzymes. The inhibitor constants (K i ) of GSH for MMP2 and MMP9 were 34 mol/L and 3 mol/L, respectively. The authors conclude that MMP inhibition is a cryptic property of both commonly used liver preservation solutions and contributes importantly to their action. Furthermore, GSH appears to be an effective inhibitor of gelatinases at concentrations at which it is normally present in extracellular fluid. (HEPATOLOGY 2000;31:1115-1122.)University of Wisconsin (UW) solution became the standard liver preservation solution more than 10 years ago. 1,2 It greatly improved the results of hepatic preservation compared with Eurocollins solution, which was in common use before that time. 1,2 UW solution was formulated with specific ingredients to retard the 4 classical effects of hypothermiacell swelling, impaired energy metabolism, acidosis, and accumulation of precursors of reactive oxygen intermediates. 2 Metalloproteinase inhibition was not a goal of its formulation because the role of metalloproteinases in preservation injury 3 was unknown at the time that UW solution was devised.Bretschneider' s solution, also known as histidine/tryptophan/ketoglutarate solution, or HTK solution 4 is also used for liver preservation, mainly in Germany. HTK solution was originally introduced as a cardioplegic solution and was later adapted to cold preservation of organs. It was formulated to retard acidosis (histidine), to prevent membrane injury (tryptophan), and to provide a substrate for energy metabolism (ketoglutarate). Like UW solution, inhibition of metalloproteinases was not a goal of its formulation.Two recent human studies, 5,6 one of which was a randomized controlled trial, 6 compared effectiveness of UW and HTK solutions. These studies found that the sol...

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Hepatic steatosis continues to present a major challenge in liver transplantation. These organs have been shown to have increased susceptibility to cold ischemia/reperfusion (CIR) injury in comparison with otherwise comparable lean livers; the mechanisms governing this increased susceptibility to CIR injury are not fully understood. Endoplasmic reticulum (ER) stress is an important link between hepatic steatosis, insulin resistance, and metabolic syndrome. In this study, we investigated ER stress signaling and blockade in the mediation of CIR injury in severely steatotic rodent allografts. Steatotic allografts from genetically leptin-resistant rodents had increased ER stress responses and increased markers of hepatocellular injury after liver transplantation into strain-matched lean recipients. ER stress response components were reduced by the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA), and this resulted in an improvement in the allograft injury. TUDCA treatment decreased nuclear factor kappa B activation and the proinflammatory cytokines interleukin-6 and interleukin-1b. However, the predominant response was decreased expression of the ER stress cell death mediator [CCAAT/enhancer-binding protein homologous protein (CHOP)]. Furthermore, activation of inflammation-associated caspase-11 was decreased, and this linked ER stress/CHOP to proinflammatory cytokine production after steatotic liver transplantation. These data confirm ER stress in steatotic allografts and implicate this as a mediating mechanism of inflammation and hepatocyte death in the steatotic liver allograft.

Background Steatotic liver grafts tolerate ischemia-reperfusion (I/R) injury poorly, contributing to increased primary graft nonfunction following transplantation. Activation of nuclear factor kappa-B (NFκB) following I/R injury plays a crucial role in activation of pro-inflammatory responses leading to injury. Methods We evaluated the role of NFκB in steatotic liver injury by using an orthotopic liver transplant (OLT) model in Zucker rats (lean to lean or obese to lean) to define the mechanisms of steatotic liver injury. Obese donors were treated with bortezomib to assess the role of NF-κB in steatotic liver I/R injury. Hepatic levels of NF-κB and pro-inflammatory cytokines were analyzed by ELISA. Serum transaminase levels and histopathological analysis were performed to assess associated graft injury. Results I/R injury in steatotic liver results in significant increases in activation of NF-κB (40%, p<0.003), specifically the p65 subunit following transplantation. Steatotic donor pretreatment with proteasome inhibitor bortezomib (0.1 mg/kg) resulted in significant reduction in levels of activated NF-κB (0.58±0.18 vs. 1.37±0.06 O.D./min/10μg protein, p<0.003). Bortezomib treatment also reduced expression of pro-inflammatory cytokines MIP-2 compared with control treated steatotic and lean liver transplants respectively (106±17.5 vs. 443.3±49.9 vs. 176±10.6 pg/mL, p=0.02), TNF-α (223.8±29.9 vs. 518.5±66.5 vs 264.5±30.1 pg/2μg protein, p=0.003) and IL-1β (6.0±0.91 vs. 19.8±5.2 vs 5±1.7 pg/10μg protein, p= 0.02) along with a significant reduction in ALT levels (715±71 vs 3712.5±437.5 vs 606±286 U/L, p=0.01). Conclusion These results suggest that I/R injury in steatotic liver transplantation are associated with exaggerated activation of NFκB subunit p65, leading to an inflammatory mechanism of reperfusion injury and necrosis. Proteasome inhibition in steatotic liver donor reduces NFκB p65 activation and inflammatory I/R injury, improving transplant outcomes of steatotic grafts in a rat model.