HSP110 aggravates ischemia-reperfusion injury after liver transplantation by promoting NF-κB pathway

Background:Ischemia-reperfusion injury(IRI)poses a significant challenge to liver transplantation(LT).The underlying mechanism primarily involves overactivation of the immune system.Heat shock protein 110(HSP110)functions as a molecular chaperone that helps stabilize protein structures.Methods:An IRI model was established by performing LT on Sprague-Dawley rats,and HSP110 was silenced using siRNA.Hematoxylin-eosin staining,TUNEL,immunohistochemistry,ELISA and liver enzyme analysis were performed to assess IRI following LT.Western blotting and quantitative reverse transcription-polymerase chain reaction were conducted to investigate the pertinent molecular changes.Results:Our findings revealed a significant increase in the expression of HSP110 at both the mRNA and protein levels in the rat liver following LT(P<0.05).However,when rats were injected with siRNAHSP110,IRI subsequent to LT was notably reduced(P<0.05).Additionally,the levels of liver enzymes and inflammatory chemokines in rat serum were significantly reduced(P<0.05).Silencing HSP110 with siRNA resulted in a marked decrease in M1-type polarization of Kupffer cells in the liver and downregulated the NF-κB pathway in the liver(P<0.05).Conclusions:HSP110 in the liver promotes IRI after LT in rats by activating the NF-κB pathway and inducing M1-type polarization of Kupffer cells.Targeting HSP110 to prevent IRI after LT may represent a promising new approach for the treatment of LT-associated IRI.

Heme oxygenase-1 alleviates ischemia/reperfusion injury in aged liver

AIM: To investigate if ischemia/reperfusion (I/R) injury in aged liver could be alleviated by heme oxygenase-1 (HO-1).METHODS: Three groups of SD rats (16 mo old) were studied. Group 1: control donors received physiological saline 24 h before their livers were harvested; group 2: donors were pretreated with hemih 24 h before their livers were harvested; and group 3: donors received hemin 24 h before their livers were harvested and zinc protoporphyrin (ZnPP,HO-1 inhibitor) was given to recipients at reperfusion. The harvested livers were stored in University of Wisconsin solution (4 ℃) for 6 h, and then transplanted to syngeneic rats. Serum glutamic oxaloacetic transaminase (SGOT),apoptotic cells, and apoptotic gene were measured 3, 6,12, 24, 48 h after reperfusion. We measured the apoptotic index by TUNEL, determined the expression of antiapoptotic Bcl-2 and proapoptotic (caspase-3) gene products by Western blot.RESULTS: After 3, 6, 12, 24, and 48 h of reperfusion, the SGOT levels (584.4±85.8 u/L, 999.2±125.2 u/L, 423.4±161.3u/L, 257.8±95.8 u/L, and 122.4±26.4 u/L) in hemin group were significantly (all P＜0.05) lower than those in saline group (1082.2±101.2 u/L, 1775.2±328.3 u/L, 840.4±137.8 u/L,448.6±74.3 u/L, and 306.2±49.3 u/L). Liver HO-1 enzymatic activity correlated with beneficial effects of hemin and deleterious effects of adjunctive ZnPP treatment. Markedly less apoptotic (TUNEL+) liver cells 3, 6, 12, 24, and 48 h after reperfusion (5.16±0.73, 10.2±0.67, 9.28±0.78, 7.14±1.12,and 4.78±0.65) (P＜0.05) could be detected in hemin liver grafts, as compared to controls (7.82±1.05, 15.94±1.82,11.67±1.59, 8.28±1.09, and 6.36±0.67). We detected the increased levels of Bcl-2 (1.5-fold) expression and compared with saline controls. These differences were most pronounced at 12 h after transplantation. In contrast, an active form of proapoptotic caspase-3 (p20) protein was found to be 2.9-fold lower at 24 h in hemin-pretreated group, as compared to saline liver transplant controls.CONCLUSION: HO-1 overexpression can provide potent protection against cold I/R injury. This effect depends, at least in part, on HO-1-mediated inhibition of antiapoptotic mechanism.

Alleviation of ischemia/reperfusion injury in ob/ob mice by inhibiting UCP-2 expression in fatty liver

AIM： To investigate the protective effect of target suppression of uncoupling protein-2 （UCP-2） on ischemia/ reperfusion （I/R） injury in fatty liver in ob/ob mice. METHODS： Plasmids suppressing UCP-2 expression were constructed, and transfected into fatty liver cells cultured in vitro and the ob/ob mouse I/R injury model. Serum tumor necrosis factor （TNF）-α levels, UCP-2 mRNA expression, alanine aminotransferase （ALT） levels in ob/ob mice were tested, and the pathological changes in fatty liver were observed in experimental and control groups. RESULTS： In ob/ob mouse I/R models, serum TNF-α levels were significantly higher than in normal controls. After the plasmids were transfected into the cultured cells and animal models, expression of UCP-2 rnRNA was significantly reduced as compared with that in the control group （2^1.56± 0.15 vs 2^-0.45± 0.15, p 〈 0.05）. In ob/ob mouse models, in which expression of UCP-2 was suppressed, serum ALT levels were significantly lower than those of other groups, and pathological analysis revealed that injury of liver tissues was significantly alleviated. CONCLUSION： The target suppression of UCP-2 expression in fatty liver can alleviate the I/R injury in the ob/ob mice.

Heme oxygenase-1 protects donor livers from ischemia/reperfusion injury:The role of Kupffer cells

AIM:To examine whether heme oxygenase (HO)-1 overexpression would exert direct or indirect effects on Kupffer cells activation, which lead to aggravation of reperfusion injury.METHODS: Donors were pretreated with cobalt protoporphyrin (CoPP) or zinc protoporphyrin (ZnPP), HO-1 inducer and antagonist, respectively. Livers were stored at 4℃ for 24 h before transplantation. Kupffer cells were isolated and cultured for 6 h after liver reperfusion.RESULTS: Postoperatively, serum transaminases were significantly lower and associated with less liver injury when donors were pretreated with CoPP, as compared with the ZnPP group. Production of the cytokines tumor necrosis factor-α and interleukin-6 generated by Kupffer cells decreased in the CoPP group. The CD14 expression levels (RT-PCR/Western blots) of Kupffer cells from CoPP-pretreated liver grafts reduced.CONCLUSION: The study suggests that the potential utility of HO-1 overexpression in preventing ischemia/reperfusion injury results from inhibition of Kupffer cells activation.

Protective effect of curcumin against liver warm ischemia/reperfusion injury in rat model is associated with regulation of heat shock protein and antioxidant enzymes

AIM： To investigate the hypothesis that the protective effects of curcumin in hepatic warm ischemia/reperfusion （I/R） injury are associated with increasing heat shock protein 70 （Hsp70） expression and antioxidant enzyme activity. METHODS： Sixty Sprague-Dawley male rats were randomly divided into sham, I/R, C ＋ I/R groups. The model of reduced-size liver warm ischemia and reperfusion was used. Curcumin （50 mg/kg） was administered by injection through a branch of superior mesenteric vein at 30 min before ischemia in C ＋ I/R group. Five rats were used to investigate the survival during 1 wk after operation in each group. Blood samples and liver tissues were obtained in the remaining animals after 3, 12, and 24 h of reperfusion to assess serum alanine aminotransferase （ALT）, aspartate aminotransferase （AST）, liver tissue NO2- ＋ NO3-, malondialdehyde （MDA） content, superoxide dismutase （SOD）, catalase （CAT）, nitricoxide synthase （NOS） and myeloperoxidase （MPO） activity, HspT0 expression and apoptosis ratio. RESULTS： Compared with I/R group, curcumin pretreatment group showed less ischemia/reperfusioninduced injury. CAT and SOD activity and Hsp70 expression increased significantly. A higher rate of apoptosis was observed in I/R group than in C ＋ I/R group, and a significant increase of MDA, NO2^- ＋ NO3^- and MPO level in liver tissues and serum transaminase concentration was also observed in I/R group compared to C ＋ I/R group. Curcumin also decreased the activity of inducible NO synthase （iNOS） in liver after reperfusion,but had no effect on the level of endothelial NO synthase （eNOS） after reperfusion in liver. The 7 d survival rate was significantly higher in C ＋ I/R group than in I/R group. CONCLUSION： Curcumin has protective effects against hepatic I/R injury. Its mechanism might be related to the overexpression of Hsp70 and antioxidant enzymes.

EFFICACY OF URSODEOXYCHOLIC ACID IN TREATMENT OF ISCHEMIA-REPERFUSION INJURY IN LIVER TRANSPLANTATION

Objective To investigate the efficacy of ursodeoxycholic acid in treatment of ischemia-reperfusion injury （IRI） in liver transplantation. Methods Eighty liver transplantation adult recipients were preoperatively enrolled and randomized into the ursodeoxycholic acid （ UDCA ） （42 cases） and control （ 38 cases ） groups between May 2005 and June 2006. The two groups were statistically compared in liver biochemical parameters on post- transplant d 1, 7, 14, and 21. Rates of severe IRI-induced liver graft dysfunction, acute cellular rejection （ ACR ） episode, drug-induced hepatotoxicity, viral hepatitis, and recurrence of primary liver disease were measured within 3 weeks post-transplantation; and rates of vascular, biliary complications, and death were also measured within 3 months post-transplantation. Results In the UDCA group, serum levels of alanine aminotransferase （ ALT） on post-transplant d 7, 14, and 21 were significantly lower than those in the control group （ P = 0. 002,0. 030, 0. 049, respectively）. Compared with the control group, serum levels of aspartate aminotransferase （ AST） and y-Glutamyltranspeptidase （ GGT） on d 7 were also lower in the UDCA group （ P =0. 012 and 0. 025）. The cases of severe IRI- induced liver graft dysfunction in the UDCA group were significantly fewer than those in the control group （ 17. 5% vs. 26.3%, P =0. 048）. There were no significant differences in rates of ACR episode, histological Banff grading, or drug-induced hepatotoxicity within 3 weeks post-transplantation as well as rates of vascular, biliary complications, and death within 3 months post-transplantation between the two groups. We did not find any case of viral hepatitis or recurrence of primary liver disease in the study. Conclusion UDCA treatment can improve graft IRI early after liver transplantation. It significantly decreased serum ALT level and incidence of severe IRl-induced liver dysfunction within post-transplant 3 weeks. Cytoprection of hepatocytes by UDCA was more outstanding than that of bile duct when cold ischemia time was beneath 12 h. Vascular and biliary complications within 3 months post-transplantation can not be affected by UDCA administration in the study.

EFFECTS OF INFLAMMATORY CELLS IN COLD AND WARM ISCHEMIA-REPERFUSION INJURY OF THE GRAFTED LIVER

Objective To investigate whether the impairment of grafted livers after transplantation was induced by the same inflammatory cells both in cold and warm ischemia. Methods Male SD rats were divided into two groups at random,24 donor livers in each group were stored in Ringers solution at 4℃ for 120min or 240min of transplantation for blood sample and tissue specimen collection. Results Along with the prolongation of cold and warm ischemia time,the serum ALT,AST and LDH level increased gradually after transplantation.Under light microscopy,some hepatocytes presented necrosis after 3h and 6h of transplantation in cold ischemia,and neutrophilic infiltration in sinusoids were evident.Also,a large number of hepatocytes were necrotic 3h or 6h after transplantation in warm ischemia from NHBDs,and lymphocytic infiltration was evident in the sinusoids.The findings in electron microscopy was as the same as those of light microscopy,and the cells which infiltrated the sinusoids in warm ischemia were identified as T lymphocytes. Conclusion The impairment of grafted livers after transplantation appeared to be induced by two different kinds of inflammatory cells in cold and warm ischemia,that is,neutrophils mediated the cold ischemia-reperfusion,and T lymphocytes mediated the warm ischemia-reperfusion from NHBDs,but these findings are to be comfirmed in further investigations.

Spectrum of COVID-19 induced liver injury:A review report

The coronavirus disease 2019(COVID-19)pandemic has caused changes in the global health system,causing significant setbacks in healthcare systems worldwide.This pandemic has also shown resilience,flexibility,and creativity in reacting to the tragedy.The severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infection targets most of the respiratory tract,resulting in a severe sickness called acute respiratory distress syndrome that may be fatal in some individuals.Although the lung is the primary organ targeted by COVID-19 viruses,the clinical aspect of the disease is varied and ranges from asymptomatic to respiratory failure.However,due to an unorganized immune response and several affected mechanisms,the liver may also experience liver cell injury,ischemic liver dysfunction,and drug-induced liver injury,which can result in respiratory failure because of the immune system’s disordered response and other compromised processes that can end in multisystem organ failure.Patients with liver cirrhosis or those who have impaired immune systems may be more likely than other groups to experience worse results from the SARS-CoV-2 infection.We thus intend to examine the pathogenesis,current therapy,and consequences of liver damage concerning COVID-19.

Remote ischemic perconditioning prevents liver transplantation-induced ischemia/reperfusion injury in rats: Role of ROS/RNS and e NOS

AIM To investigate the underlying mechanisms of the protective role of remote ischemic perconditioning (RIPerC) in rat liver transplantation. METHODS Sprague-Dawley rats were subjected to sham, orthotopic liver transplantation (OLT), ischemic postconditioning (IPostC) or RIPerC. After 3 h reperfusion, blood samples were taken for measurement of alanine aminotransferase, aspartate aminotransferase, creatinine (Cr) and creatinine kinase-myocardial band (CK-MB). The liver lobes were harvested for the following measurements: reactive oxygen species (ROS), H2O2, mitochondrial membrane potential (Delta psi m) and total nitric oxide (NO). These measurements were determined using an ROS/H2O2, JC1 and Total NOx Assay Kit, respectively. Endothelial NO synthase (eNOS) was analyzed by reverse transcription-polymerase chain reaction (RTPCR) and western blotting, and peroxynitrite was semiquantified by western blotting of 3-nitrotyrosine. RESULTS Compared with the OLT group, the grafts subjected to RIPerC showed significantly improved liver and remote organ functions (P < 0.05). ROS (P < 0.001) including H2O2 (P < 0.05) were largely elevated in the OLT group as compared with the sham group, and RIPerC (P < 0.05) reversed this trend. The collapse of Delta psi m induced by OLT ischemia/reperfusion (I/R) injury was significantly attenuated in the RIPerC group (P < 0.001). A marked increase of NO content and phosphoserine eNOS, both in protein and mRNA levels, was observed in liver graft of the RIPerC group as compared with the OLT group (P < 0.05). I/R-induced 3-nitrotyrosine content was significantly reduced in the RIPerC group as compared with the OLT group (P < 0.05). There were no significant differences between the RIPerC and IPostC groups for all the results except Cr. The Cr level was lower in the RIPerC group than in the IPostC group (P < 0.01). CONCLUSION Liver graft protection by RIPerC is similar to or better than that of IPostC, and involves inhibition of oxidative stress and up-regulation of the PI3K/Akt/eNOS/NO pathway.

Nuclear factor-KB decoy oligodeoxynucleotides attenuates ischemia/reperfusion injury in rat liver graft

AIM： To evaluate the protective effect of NF-kB decoy oligodeoxynucleotides （ODNs） on ischemia/reperfusion （I/R） injury in rat liver graft. METHODS： Orthotopic syngeneic rat liver transplantation was performed with 3 h of cold preservation of liver graft in University of Wisconsin solution containing phosphorothioated double-stranded NF-kB decoy ODNs or scrambled ODNs. NF-kB decoy ODNs or scrambled ODNs were injected intravenously into donor and recipient rats 6 and 1 h before operation, respectively. Recipients were killed 0 to 16 h after liver graft reperfusion. NF-kB activity in the liver graft was analyzed by electrophoretic mobility shift assay （EMSA）. Hepatic mRNA expression of TNF-α, IFN-γ and intercellular adhesion molecule-1 （ICAM-1） were determined by semiquantitative RT-PCR. Serum levels of TNF-α and IFN-γ were measured by enzyme-linked immunosorbent assays （ELISA）. Serum level of alanine transaminase （ALT） was measured using a diagnostic kit. Liver graft myeloperoxidase （MPO） content was assessed. RESULTS： NF-kB activation in liver graft was induced in a time-dependent manner, and NF-kB remained activated for 16 h after graft reperfusion. NF-kB activation in liver graft was significant at 2 to 8 h and slightly decreased at 16 h after graft reperfusion. Administration of NF-kB decoy ODNs significantly suppressed NF-kB activation as well as mRNA expression of TNF-α, IFN-γ, and ICAM-1 in the liver graft. The hepatic NF-kB DNA binding activity [presented as integral optical density （IOD） value] in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （2.16±0.78 vs 36.78 ±6.35 and 3.06±0.84 vs 47.62± 8.71 for IOD value after 4 and 8 h of reperfusion, respectively, P〈0.001）. The hepatic mRNA expression level of TNF-α, IFN-γ and ICAM-1 rpresented as percent of β-actin mRNA （%）] in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （8.31 ±3.48 vs 46.37±10.65 and 7.46± 3.72 vs 74.82±12.25 for hepatic TNF-α mRNA, 5.58±2.16 vs 50.46±9.35 and 6.47±2.53 vs 69.72±13.41 for hepatic IFN-γ mRNA, 6.79 ±2.83 vs 46.23±8.74 and 5.28±2.46 vs 67.44±10.12 for hepatic ICAM-1 mRNA expression after 4 and 8 h of reperfusion, respectively, P〈0.001）. Administration of NF-kB decoy ODNs almost completely abolished the increase of serum level of TNF-α and IFN-γ induced by hepatic ischemia/reperfusion, the serum level （pg/mL） of TNF-α and in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （42.7±13.6 vs 176.7±15.8 and 48.4±15.1 vs 216.8±17.6 for TNF-α level, 31.5±12.1 vs 102.1±14.5 and 40.2±13.5 vs 118.6±16.7 for IFN-γ level after 4 and 8 h of reperfusion, respectively, P〈0.001）. Liver graft neutrophil recruitment indicated by MPO content and hepatocellular injury indicated by serum ALT level were significantly reduced by NF-kB decoy ODNs, the hepatic MPO content （A655） and serum ALT level （IU/L） in the NF-kB decoy ODNs treatment group rat was significantly lower than that of the I/R group rat （0.17±0.07 vs 1.12±0.25 and 0.46±0.17 vs 1.46±0.32 for hepatic MPO content, 71.7±33.2 vs 286.1±49.6 and 84.3±39.7 vs 467.8±62.3 for ALT level after 4 and 8 h of reperfusion, respectively, P〈0.001）. CONCLUSION： The data suggest that NF-kB decoy ODNs protects against I/R injury in liver graft by suppressing NF-kB activation and subsequent expression of proinflammatory mediators.

Intravenous administration of glutathione protects parenchymal and non-parenchymal liver cells against reperfusion injury following rat liver transplantation

AIM:To investigate the effects of intravenous administration of the antioxidant glutathione (GSH) on reperfusion injury following liver transplantation. METHODS:Livers of male Lewis rats were transplanted after 24 h of hypothermic preservation in University of Wisconsin solution in a syngeneic setting.During a 2-h reperfusion period either saline (controls,n=8) or GSH (50 or 100 μmol/(h·kg),n=5 each) was continuously administered via the jugular vein. RESULTS:Two hours after starting reperfusion plasma ALT increased to 1 457±281 U/L (mean±SE) in controls but to only 908±187 U/L (P<0.05) in animals treated with 100 μmol GSH/(h·kg).No protection was conveyed by 50μmol GSH/(h·kg).Cytoprotection was confirmed by morphological findings on electron microscopy:GSH treatment prevented detachment of sinusoidal endothelial cells (SECs) as well as loss of microvilli and mitochondrial swelling of hepatocytes.Accordingly,postischemic bile flow increased 2-fold.Intravital fluorescence microscopy revealed a nearly complete restoration of sinusoidal blood flow and a significant reduction of leukocyte adherence to sinusoids and postsinusoidal venules.Following infusion of 50μmol and 100 μmol GSH/(h·kg),plasma GSH increased to 65±7 mol/L and 97±18 mol/L,but to only 20±3 mol/L in untreated recipients. Furthermore,plasma glutathione disulfide (GSSG) increased to 7.5±1.0 mol/L in animals treated with 100μmol/(h·kg) GSH but infusion of 50μmol GSH/(h·kg) did not raise levels of untreated controls (1.8±0.5 mol/L vs 2.2±0.2 mol/L). CONCLUSION:Plasma GSH levels above a critical level may act as a “sink” for ROS produced in the hepatic vasculature during reperfusion of liver grafts.Therefore,GSH can be considered a candidate antioxidant for the Drevention of reperfusion injury after liver transplantation,in particular since it has a low toxicity in humans.

Hepatocellular glycogen in alleviation of liver ischemia reperfusion injury

Objective: To study the mechanism of hepatocellular glycogen in alleviation of liver ischemia-reperfusion injury during hepatic vascular occlusion for partial hepatectomy. Methods: Seventeen patients were randomly divided into experimental group (n=9) and control group (n=8). In the experimental group, patients were given high concentration glucose intravenously during 24 hours before operation. The hepatic lesion was re- sected after portal triad clamping in the two groups. Non-cancer liver tissue was biopsied to measure he- patic tissue ATP content and change of malondialde- hyde (MDA) and superoxide dismutase (SOD). Liver function of all patients was assessed before operation and the first and fifth day after operation. Results: Hepatic tissue ATP content of the experi- mental group was significantly higher than that of the control group both at the end of hepatic vascular oc- clusion and the point of one-hour reperfusion. Be- sides, liver function of the experimental group was significantly better than that of the control group the first and fifth day after operation. There was signifi- cant difference in SOD activity or MDA content be- tween the two groups at the end of hepatic vascular occlusion and at the point of one-hour reperfusion. Conclusions: Abundant intracellular glycogen may reduce liver ischemia-reperfusion injury caused by hepatic vascular occlusion. It is beneficial to give a large amount of glucose before a complex liver opera- tion, in which temporary occlusion of hepatic blood flow is necessary.

Nigella sativa relieves the deleterious effects of ischemia reperfusion injury on liver

AIM: To determine whether Nigella sativa prevents hepatic ischemia-reperfusion injury to the liver. METHODS: Thirty rats were divided into three groups as sham (Group 1), control (Group 2), and Nigella sati-va (NS) treatment group (Group 3). All rats underwent hepatic ischemia for 45 min followed by 60 min period of reperfusion. Rats were intraperitoneally infused with only 0.9% saline solution in group 2. Rats in group 3 received NS (0.2 mL/kg) intraperitoneally, before isch-emia and before reperfusion. Blood samples and liver tissues were harvested from the rats, and then the rats were sacrifi ced. Serum aspartate aminotransfera-se (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) levels were determined. Total antioxidant capacity (TAC), catalase (CAT), total oxida-tive status (TOS), oxidative stress index (OSI) and my-eloperoxidase (MPO) in hepatic tissue were measured. Also liver tissue histopathology was evaluated by light microscopy. RESULTS: The levels of liver enzymes in group 3 weresignifi cantly lower than those in the group 2. TAC in liver tissue was significantly higher in group 3 than in group 2. TOS, OSI and MPO in hepatic tissue were signifi cantly lower in group 3 than the group 2. Histo-logical tissue damage was milder in the NS treatment group than that in the control group. CONCLUSION: Our results suggest that Nigella sa-tiva treatment protects the rat liver against to hepatic ischemia-reperfusion injury.

Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

Liver ischemia-reperfusion injury(IRI) is an inherent feature of liver surgery and liver transplantation in which damage to a hypoxic organ(ischemia) is exacerbated following the return of oxygen delivery(reperfusion). IRI is a major cause of primary nonfunction after transplantation and may lead to graft rejection, regardless of immunological considerations. The immediate response involves the disruption of cellular mitochondrial oxidative phosphorylation and the accumulation of metabolic intermediates during the ischemic period, and oxidative stress during blood flow restoration. Moreover, a complex cascade of inflammatory mediators is generated during reperfusion, contributing to the extension of the damage and finally to organ failure. A variety of pharmacological interventions(antioxidants, anticytokines, etc.) have been proposed to alleviate graft injury but their usefulness is limited by the local and specific action of the drugs and by their potential undesirable toxic effects. Polyethylene glycols(PEGs), which are non-toxic water-soluble compounds approved by the FDA, have been widely used as a vehicle or a base in food, cosmetics and pharmaceuticals, and also as adjuvants for ameliorating drug pharmacokinetics. Some PEGs are also currently used as additives in organ preservation solutions prior to transplantation in order to limit the damage associated with cold ischemia reperfusion. More recently, the administration of PEGs of different molecular weights by intravenous injection has emerged as a new therapeutic tool to protect liver grafts from IRI. In this review, we summarize the current knowledge concerning the use of PEGs as a useful target for limiting liver IRI.

Diazoxide attenuates ischemia/reperfusion injuryvia upregulation of heme oxygenase-1 after liver transplantation in rats

AIM:To evaluate the effects of diazoxide on ischemia/reperfusion(I/R)-injured hepatocytes and further elucidate its underlying mechanisms.METHODS:Male Sprague-Dawley rats were randomized(8 for donor and recipient per group)into five groups:I/R group(4 h of liver cold ischemia followed by 6 h of reperfusion);heme oxygenase-1(HO-1)small interfering RNA(siRNA)group(injection of siRNA via donor portal vein 48 h prior to harvest);diazoxide(DZ) group(injection of DZ via donor portal vein 10 min prior to harvest);HO-1 siRNA+DZ group;and siRNA control group.Blood and liver samples were collected at 6 h after reperfusion.The mRNA expressions and protein levels of HO-1 were determined by reverse transcription polymerase chain reaction and Western blotting,and tissue morphology was examined by light and transmission electron microscopy.Serum transaminases level and cytokines concentration were also measured.RESULTS:We observed that a significant reduction of HO-1 mRNA and protein levels in HO-1 siRNA and HO-1 siRNA+DZ group when compared with I/R group,while the increases were prominent in the DZ group.Light and transmission electron microscopy indicated severe disruption of tissue with lobular distortion and mitochondrial cristae damage in the HO-1 siRNA and HO-1 siRNA+DZ groups compared with DZ group.Serum alanine aminotransferase,aspartate transaminase,tumor necrosis factor-αand interleukin-6 levels increased in the HO-1 siRNA and HO-1 siRNA+DZ groups,and decreased in the DZ group.CONCLUSION:The protective effect of DZ may be induced by upregulation of HO-1.By inhibiting expression of HO-1,this protection pretreated with DZ was abolished.

Protective effects of L-arginine against ischemia-reperfusion injury in non-heart beating rat liver graft

BACKGROUND: Although the use of non-heart beating donors (NHBDs) could bridge the widening gap between organ demand and supply, its application to liver transplantation is limited due to the high incidence of primary graft loss. Prevention of liver injury in NHBDs will benefit the results of transplantation. This study was conducted to evaluate the protective effects of L-arginine on liver grafts from NHBDs. METHODS: One hundred and four Wistar rats were randomly divided into 7 groups: normal control (n=8) controls 1, 2 and 3 (C-1, C-2, C-3, n=16), and experimental 1, 2 and 3 (E-1, E-2, E-3, n=16). For groups C-1 and E-1, C-2 and E-2, and C-3 and E-3, the warm ischemia time was 0, 30, and 45 minutes, respectively. Liver grafts were flushed with and preserved in 4 degrees C Euro-collins solution containing 1 mmol/L L-arginine for 1 hour in each experimental group. Recipients of each experimental group were injected with L-arginine (10 mg/kg body weight) by tail vein 10 minutes before portal vein reperfusion. Donors and recipients of each experimental control group were treated with normal saline. Then transplantation was performed. At 1, 3, and 24 hours after portal vein reperfusion, blood samples were obtained to determine the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), nitric oxide (NO) and plasma endothelin (ET). At 3 hours after portal vein reperfusion, grafts samples were fixed in 2.5% glutaraldehyde for electron microscopic observation. RESULTS: At I hour after portal vein reperfusion, the levels of NO in groups E-1, E-2, E-3 and C-1, C-2, C-3 were lower, while the levels of plasma ET, serum ALT and AST were higher than those in the normal control group (P<0.05). At 1, 3, and 24 hours, the levels of NO in groups E-1, E-2, E-3 were higher, while the levels of plasma ET, serum ALT and AST were lower than those in the corresponding control groups (C-1, C-2, C-3) (P<0.05). The levels of NO in groups C-2 and C-3 were lower than in group C-1 (P<0.05), and the level of NO in group C-3 was lower than in group C-2 (P<0.05). At 1, 3 and 24 hours, the levels of plasma ET, serum ALT, and AST in groups E-1, E-2, E-3 were lower than those in the corresponding control groups (C-1, C-2, C-3) (P<0.05). The levels of plasma ET, serum ALT, and AST were lower in group C-3 than in groups C-1 and C-2 (P<0.05). Pathological changes in groups E-1, E-2, E-3 were milder than those in the corresponding experimental control groups (C-1, C-2, C-3). CONCLUSIONS: The imbalance between NO and ET plays an important role in the development of ischemia-reperfusion injury of liver grafts from NHBDs. L-arginine can attenuate injury in liver grafts from NHBDs by improving the balance between NO and ET.

Effect of Shenfu injection on ischemia-reperfusion injury of rat liver graft

BACKGROUND: It is reported that Shenfu injection (an injection prepared from traditional Chinese medicines red ginseng and aconite root) can decrease the extent of ischemia-reperfusion injury to many organs, such as the heart and kidney. We therefore investigated the effect of Shenfu injection on ischemia-reperfusion injury of rat liver graft and its mechanism. METHODS: Male Sprague Dawley (SD) rats were used as a model for isogeneic orthotopic liver transplantation. Sixty rats were randomly devided into two groups (30 in each group). The recipient was given intravenous Shenfu injection immediately before the removal of the liver in the Shenfu group and normal saline of the same volume in the control group. At 3, 6 and 24 hours after the reperfusion, blood and hepatic tissue were taken for examination. RESULTS: The levels of superoxide dismutase (SOD) and nitric oxide (NO) increased more significantly in the Shenfu group than in the control group (P <0.05). The levels of serum liver enzymes, hyaluronic acid (HA), malondialde-hyde (MDA), tumor necrosis factor-alpha(TNF-α), inter-leukin-1 (IL-1), endothelin -1 (ET-1) and liver cell apopto-sis index were lower in the Shenfu group than in the control group (P <0. 05). Microscopic examination revealed that the morphological changes of hepatic tissue were more severe in the control group than in the Shenfu group. CONCLUSIONS: Shenfu injection has protective effect on ischemia-reperfusion injury of rat liver graft. It inhibits the production of oxygen free radical and the activation of Kupffer cells, decreases apoptosis of liver cell, and improves microcirculation.

Role of NF-kappaB in Liver Ischemia Reperfusion Injury of Rats

To determine the role of NF-kappaB in ischemia reperfusion (I/R) injury of the rat liver, rats underwent partial hepatic ischemia and reperfusion. The left and median lobes of the liver were subjected to ischemia for 90 min followed by reperfusion for defined times. NF-kappaB activity was analyzed by electrophoretic mobility shift assay (EMSA). Semiquantitative reverse-transcriptase polymerase chain reaction was used to analyze TNF-α and ICAM-1 mRNA levels. Results showed during liver I/R injury, NF-kappaB activation was induced in a time dependent manner. NF-kappaB was activated within 1h and 2h after the initiation of reperfusion and decreased after 4 h. Messenger RNA expression of TNF-α and ICAM-1 were increased after the reperfusion of 2 h. It was concluded that during hepatic I/R injury, NF-kappaB was activated and could bind to special sequence in the promoters of budget genes, which can up-regulate the expression of TNF-α and ICAM-1 mRNA to result in ischemia reperfusion injury of the rat liver.

Protective effect of hydrogen-rich saline on liver ischemia-reperfusion injury in mice

Objective To explore protective effect of hydrogen - rich saline on liver ischemia reperfusion ( IR) in mice and possible mechanisms. Methods Twenty - four C57BL /6 mice were randomly divided into 3 groups: sham - operated group,control group ( mice were injec-

Early markers of reperfusion injury after liver transplantation: association with primary dysfunction

BACKGROUND： In patients with end-stage fiver disease, fiver transplantation is the only available curative treatment. Al- though the outcome and quality of life in the patients have improved over the past decades, primary dys- or nonfimction （PDF/PNF） can occur. Early detection of PDF and PNF is crucial and could lead to individual therapies. This study was designed to identify early markers of reperfusion injury and PDF in liver biopsies taken during the first hour after reperfusion.