Orit Pappo

Reduced hepatic injury in Toll-like receptor 4-deficient mice following D-galactosamine/lipopolysaccharide-induced fulminant hepatic failure.

Liver transplantation is the only therapy of proven benefit in fulminant hepatic failure (FHF). Lipopolysaccharide (LPS), D-galactosamine (GalN)-induced FHF is a well established model of liver injury in mice. Toll-Like Receptor 4 (TLR4) has been identified as a receptor for LPS. The aim of this study was to investigate the role of TLR4 in FHF induced by D-GalN/LPS administration in mice. Wild type (WT) and TLR4 deficient (TLR4ko) mice were studied in vivo in a fulminant model induced by GalN/LPS. Hepatic TLR4 expression, serum liver enzymes, hepatic and serum TNF-α and interleukin-1β levels were determined. Apoptotic cells were identified by immunohistochemistry for caspase-3. Nuclear factor-kappaβ (NF-ĸ β) and phosphorylated c-Jun hepatic expression were studied using Western blot analysis. All WT mice died within 24 hours after administration of GalN/LPS while all TLR4ko mice survived. Serum liver enzymes, interleukin-1β, TNF-α level, TLR4 mRNA expression, hepatic injury and hepatocyte apoptosis all significantly decreased in TLR4ko mice compared with WT mice. A significant decrease in hepatic c-Jun and IĸB signaling pathway was noted in TLR4ko mice compared with WT mice. In conclusion, following induction of FHF, the inflammatory response and the liver injury in TLR4ko mice was significantly attenuated through decreased hepatic c-Jun and NF-ĸB expression and thus decreased TNF-α level. Down-regulation of TLR4 expression plays a pivotal role in GalN/LPS induced FHF. These findings might have important implications for the use of the anti TLR4 protein signaling as a potential target for therapeutic intervention in FHF.

Circulating soluble cytochrome c in liver disease as a marker of apoptosis.

Abstract. Ben‐Ari Z, Schmilovotz‐Weiss H, Belinki A, Pappo O, Sulkes J, Neuman MG, Kaganovsky E, Kfir B, Tur‐Kaspa R, Klein T (Beilinson and Golda Campuses, Rabin Medical Center, Petah Tiqva and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel, and In Vitro Toxicology Laboratory, Sunnybrook Womens College, Toronto, Canada) Circulating soluble cytochrome c in liver disease as a marker of apoptosis. J Intern Med 2003; 254: 168–175.

Recombinant human erythropoietin attenuates hepatic injury induced by ischemia/reperfusion in an isolated mouse liver model

IntroductionApoptosis is a central mechanism of cell death following reperfusion of the ischemic liver. Recombinant human erythropoietin (rhEPO) have an important role in the treatment of myocardial ischemia/reperfusion (I/R) injury, by preventing apoptosis. The aim of the study was to investigate the effect of different regimens of rhEPO in preventing apoptosis following I/R-induced hepatic injury.Material and methodsIsolated mouse livers were randomly divided into five groups: (1) control group, perfused for the whole study period (105xa0min); (2) 30-min perfusion followed by 90xa0min of ischemia and 15xa0min of reperfusion; (3), (4) and (5) like group 2, but with administration of rhEPO 5,000xa0units/kg i.p. at 30xa0min, 24xa0h, or both 30xa0min and 24xa0h respectively, before induction of ischemia. Perfusate liver enzyme levels and intrahepatic caspase-3 activity were measured, and apoptotic cells were identified by morphological criteria, TUNEL assay, and immunohistochemistry for caspase-3. Using immunoblot the expression of the proapoptotic JNK and inhibitor of NFκB (IκBα) were also evaluated. von Willebrand factor (vWF) immunohistochemistry was used as a marker of endothelial cells.ResultsCompared to the I/R livers, all 3 rhEPO pretreated groups showed: a significant reduction in liver enzyme levels (Pxa0<xa00.05) and intrahepatic caspase-3 activity (Pxa0<xa00.05), fewer apoptotic hepatocytes (Pxa0<xa00.05) and positive vWF staining in numerous endothelial cells lining the sinusoids. EPO decreased JNK phosphorylation and the degradation of the inhibitor of NFκB (IκBα) during I/R. There was no added benefit of the multiple- over the single-dose rhEPO regimen.ConclusionPretreatment with one dose of rhEPO can attenuate post-I/R hepatocyte apoptotic liver damage. NFκB and JNK activation is likely to play a pivotal role in the pathophysiology of I/R hepatic injury and might have a key role in EPO-mediated protective effects. This effect is associated with the increase in sinusoidal vWF immunostaining suggests an additional effect of rhEPO in liver angiogenesis recovery. These findings have important implications for the potential use of rhEPO in I/R injury during liver transplantation.

Serum protein N-glycans profiling for the discovery of potential biomarkers for nonalcoholic steatohepatitis.

The hepatic histology in nonalcoholic fatty liver disease can vary from isolated hepatic steatosis to steatohepatitis can progress to cirrhosis and liver-related death. The aim was to evaluate the use of blood serum N-glycan fingerprinting as a tool for differential diagnosis of nonalcoholic steatohepatitis from steatosis. A group of 47 patients with NAFLD was diagnosed by clinical laboratory analysis and ultrasonography, and was studied histologically using the Brunts scoring system. The control group included 13 healthy individuals. N-glycan profiles of serum proteins were determined by DNA sequencer-based carbohydrate analytical profiling. We have found that the concentrations of two glycans (NGA2F and NA2) and their logarithm ratio of NGA2F versus NA2 (named GlycoNashTest) were associated with the degree of NASH-related fibrosis, but had no correlation with the grade of inflammation nor steatosis severity. When used to screen NAFLD patients, GlycoNashTest could identify advanced NASH-related fibrosis (F3-F4) with the diagnosis sensitivity of 89.5% and specificity of 71.4%. The serum N-glycan profile is a promising noninvasive method for detecting NASH or NASH-related fibrosis in NAFLD patients, which could be a valuable supplement to other markers currently used in diagnosis of NASH.

Magnetic resonance cholangiopancreatography for the accurate diagnosis of biliary complications after liver transplantation: comparison with endoscopic retrograde cholangiography and percutaneous transhepatic cholangiography – long‐term follow‐up

Katz LH, Benjaminov O, Belinki A, Geler A, Braun M, Knizhnik M, Aizner S, Shaharabani E, Sulkes J, Shabtai E, Pappo O, Atar E, Tur‐Kaspa R, Mor E, Ben‐Ari Z. Magnetic resonance cholangiopancreatography for the accurate diagnosis of biliary complications after liver transplantation: comparison with endoscopic retrograde cholangiography and percutaneous transhepatic cholangiography – long‐term follow‐up.u2028Clin Transplant 2010: 24: E163–E169.

Syncytial giant-cell hepatitis due to autoimmune hepatitis type II (LKM1+) presenting as subfulminant hepatitis

Giant cell hepatitis (GCH) in adults is a rare event. The diagnosis of GCH is based on findings of syncytial giant hepatocytes. It is commonly associated with either viral infection or autoimmune hepatitis type I. A patient with GCH due to autoimmune hepatitis type II (LKM1+) is described, a combination that has not been previously reported. Corticosteroid therapy was effective in decreasing serum liver enzymes; however, the patient deteriorated rapidly and developed subfulminant hepatic failure. Although an emergency orthotopic liver transplantation was performed, the patient died because of reperfusion injury. Interestingly, only a few giant hepatocytes were noted in the explanted liver. This case stresses the association of GCH with autoimmune disorders, the possible immune mechanism involved in the formation of giant cell hepatocytes, and illustrates the rapidly progressive course and unfavorable prognosis that these patients can develop.

Bax ablation protects against hepatic ischemia/reperfusion injury in transgenic mice

Apoptosis appears to be a central mechanism of cell death following reperfusion of the ischemic liver. The aim of this study was to determine the effect of decreased expression of the proapoptotic Bax gene on hepatic apoptotic warm ischemia/reperfusion (I/R) injury. Three groups of mice were studied: homozygotic knockout mice (Bax−/−); heterozygotic (Bax+/−); and wild type (Bax+/+). Isolated mouse livers were subjected to 90 minutes of ischemia (37°C) followed by 15 minutes of reperfusion. Bax and Bcl‐2 expression in liver tissue homogenates was measured by Western blot. Serum liver enzyme levels were measured and intrahepatic caspase‐3 activity was determined by fluorimetric assay. Oil red O (ORO) staining was performed for fat detection. Apoptotic cells were identified by morphological criteria, immunohistochemistry for caspase‐3, and terminal deoxynucleotidyl transferase‐mediated 2′‐deoxyuridine 5′‐triphosphate nick‐end labeling (TUNEL) assay. At 1 minute of reperfusion, the ischemic (Bax−/−) livers were characterized by statistically significantly lower liver enzyme levels and lower caspase‐3 activity than the ischemic (Bax+/+) livers (P < 0.05 for both). The reduction in postischemic apoptotic hepatic injury in the ischemic Bax−/− livers group was confirmed morphologically, by the significantly reduced microvesicular steatosis as determined by ORO staining, fewer apoptotic hepatocyte cells detected (P < 0.05); immunohistochemically, by the significantly weaker activation of caspase‐3 compared to the ischemic group (P < 0.05); and by TUNEL assay (P < 0.05). Similar levels of antiapoptotic Bcl‐2 protein expression were detected in all 3 groups of ischemic livers on Western blots. Bax protein was not expressed in Bax‐deficient livers and was detected in Bax+/+ normal livers. In the Bax+/− livers, levels of the damage markers were moderate. In conclusion, The better tolerance of Bax knockout livers to I/R injury suggests that the Bax gene may serve as a potential target for therapeutic intervention in hepatic I/R injury. Liver Transpl 13:1181–1188, 2007.

Effect of adenosine A2A receptor agonist (CGS) on ischemia/reperfusion injury in isolated rat liver.

Ischemia/reperfusion injury during liver transplantation is a major cause of primary nonfunctioning graft for which there is no effective treatment other than retransplantation. Adenosine prevents ischemia-reperfusion-induced hepatic injury via its A2A receptors. The aim of this study was to investigate the role of A2A receptor agonist on apoptotic ischemia/reperfusion-induced hepatic injury in rats. Isolated rat livers within University of Wisconsin solution were randomly divided into four groups: (1) continuous perfusion of Krebs-Henseleit solution through the portal vein for 165 minutes (control); (2) 30-minute perfusion followed by 120 minutes of ischemia and 15 minutes of reperfusion; (3) like group 2, but with the administration of CGS 21680, an A2A receptor agonist, 30 μ g/100 ml, for 1 minute before ischemia; (4) like group 3, but with administration of SCH 58261, an A2A receptor antagonist. Serum liver enzyme levels were measured by biochemical analysis, and intrahepatic caspase-3 activity was measured by fluorometric assay; apoptotic cells were identified by morphological criteria, the terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) fluorometric assay, and immunohistochemistry for caspase-3. Results showed that at 1 minute of reperfusion, there was a statistically significant reduction in liver enzyme levels in the animals pretreated with CGS (p < 0.05). On fluorometric assay, caspase-3 activity was significantly decreased in group 3 compared to group 2 (p < 0.0002). The reduction in postischemic apoptotic hepatic injury in the CGS-treated group was confirmed morphologically, by the significantly fewer apoptotic hepatocyte cells detected (p < 0.05); immunohistochemically, by the significantly weaker activation of caspase-3 compared to the ischemic group (p < 0.05); and by the TUNEL assay (p < 0.05). In conclusion, the administration of A2A receptor agonist before induction of ischemia can attenuate postischemic apoptotic hepatic injury and thereby minimize liver injury. Apoptotic hepatic injury seems to be mediated through caspase-3 activity.

Ischemia and Reperfusion Liver Injury is Reduced in the Absence of Toll-like Receptor 4

Background/Aims: Toll-like receptor 4 (TLR4) is expressed on hepatic non-parenchymal cells and hepatocytes. Hepatic signaling through TLR4 is critical in the pathogenesis of ischemia reperfusion injury (IRI) and leads to the release of cytokines. The role of bone marrow-derived TLR4 in the early reperfusion stage is unclear. Methods: We used wild type mice (WT), TLR4deficient (TLR4ko) mice and chimeras to dissociate between the role of TLR4 expression in the liver (TLR4ko/WT) and in the immuno-hematopoietic system (WT/TLR4ko) in mouse hepatic IR injury model. Mice were subjected to in vivo partial IRI (70% for 60 min). Results: Compared with WT IR livers, TLR4ko IRI mice (4 hours) showed a significant reduction in serum liver enzyme, hepatic TNF-α and interleukin-1β levels. Fewer apoptotic hepatocytes cells were identified by morphological criteria and immunohistochemistry for caspase-3. In TLR4ko mice, decreased hepatic CJUN and NF-ĸB expression during IRI was noted compared with WT mice. Chimeric mice having either TLR4 bone-marrow or non-bone marrow derived cells following IRI exhibited almost similar hepatic injury as WT mice in the immediate reperfusion stage. Conclusion: Both TLR4 bone marrow-derived and non-bone marrow-derived cells are necessary in the initial process of hepatic injury. Activating TLR4-dependent signaling is required for IRI. The absence of the TLR4 gene plays a pivotal role in reducing hepatic IR injury.

Platelet-Derived Growth Factor Gene Polymorphism in Recurrent Hepatitis C Infection after Liver Transplantation

Background. Recurrent hepatitis C virus (HCV) infection is particularly aggressive in the post liver transplantation setting, with rapid progression of liver fibrosis. Platelet-derived growth factor (PDGF) is reportedly involved in the pathogenesis of liver fibrosis. The aim of this study was to evaluate the possible contribution of molecular variants of the PDGF-B gene to recurrent HCV infection after liver transplantation. Methods. DNA was extracted from peripheral blood mononuclear cells of 40 patients who underwent liver transplantation for chronic HCV infection and genotyped for polymorphisms in PDGF-B at positions +1135 (A to C) and +286 (A to G). Intrahepatic PDGF-B expression was detected by immunohistochemistry and assessed semiquantitatively. Forty-seven healthy individuals served as controls. Results. Recurrent HCV infection occurred in 34 patients (85%) after a median interval of 10.5 months (range 1.5–60.0). A statistically significant difference was observed in the distribution of the PDGF-B gene polymorphism at position +1135, but not +286 between patients and controls (P=0.05). The A/A genotype occurred at a highly significantly increased rate in patients with recurrent HCV infection than in those without (64.7% vs. 16.67%, P=0.0001), and in patients with severe than in those with nonsevere recurrence (100% vs. 53.85%, P=0.05). The expression level of intrahepatic PDGF-B was found to be highly correlated with the fibrosis stage (P<0.0001). Further analysis yielded a highly statistically significant relationship between the PDGF-B gene polymorphism at position +1135 and clinical parameters of disease severity. Conclusions. PDGF-B gene polymorphism appears to be associated with severe recurrent HCV infection after liver transplantation. PDGF-B may play an essential role in the development and progression of hepatic fibrosis. These findings, if confirmed, may have important therapeutic implications.