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.

N-acetylcysteine attenuates reactive-oxygen-speciesmediated endoplasmic reticulum stress during liver ischemia-reperfusion injury

AIM: To investigate the effects of N-acetylcysteine (NAC) on endoplasmic reticulum (ER) stress and tissue injury during liver ischemia reperfusion injury (IRI).

Remote ischemic preconditioning protects liver ischemia-reperfusion injury by regulating eNOS-NO pathway and liver microRNA expressions in fatty liver rats

BACKGROUND: Ischemic preconditioning (IPC) is a strategy to reduce ischemia-reperfusion (I/R) injury. The protective effect of remote ischemic preconditioning (RIPC) on liver I/R injury is not clear. This study aimed to investigate the roles of RIPC in liver I/R in fatty liver rats and the involvement of endothelial nitric oxide synthase-nitric oxide (eNOS-NO) pathway and microRNA expressions in this process. METHODS: A total of 32 fatty rats were randomly divided into the sham group, I/R group, RIPC group and RIPC+I/R group. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and nitric oxide (NO) were measured. Hematoxylin-eosin staining was used to observe histological changes of liver tissues, TUNEL to detect hepatocyte apoptosis, and immunohistochemistry assay to detect heat shock protein 70 (HSP70) expression. Western blotting was used to detect liver inducible NOS (iNOS) and eNOS protein levels and realtime quantitative polymerase chain reaction to detect miR-34a, miR-122 and miR-27b expressions. RESULTS: Compared with the sham and RIPC groups, serum ALT, AST and iNOS in liver tissue were significantly higher in other two groups, while serum NO and eNOS in liver tissue were lower, and varying degrees of edema, degeneration and inflammatory cell infiltration were found. Cell apoptosis number was slightly lower in the RIPC+I/R group than that in I/R group. Compared with the sham group, HSP70 expressions were significantly increased in other three groups (all P<0.05). Compared with the sham and RIPC groups, elevated miR-34a expressions were found in I/R and RIPC+I/R groups (P<0.05). MiR-122 and miR-27b were found significantly decreased in I/R and RIPC+I/R groups compared with the sham and RIPC groups (all P<0.05). CONCLUSION: RIPC can reduce fatty liver I/R injury by affecting the eNOS-NO pathway and liver microRNA expressions.

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.

Influence of Kupffer cells and platelets on ischemia-reperfusion injury in mild steatotic liver

AIM: To investigate the effect of mild steatotic liver on ischemia-reperfusion injury by focusing on Kupffer cells (KCs) and platelets. METHODS: Wistar rats were divided into a normal liver group (N group) and a mild steatotic liver group (S group) induced by feeding a choline-deficient diet for 2 wk. Both groups were subjected to 20 min of warm ischemia followed by 120 min of reperfusion. The number of labeled KCs and platelets in sinusoids and the blood perfusion in sinusoids were observed by intravital microscopy (IVM), which was performed at 30, 60 and 120 min after reperfusion. To evaluate serum alanine aminotransferase as a marker of liver deterioration, blood samples were taken at the same time as IVM.RESULTS: In the S group, the number of platelets adhering to KCs decreased significantly compared with the N group (120 after reperfusion; 2.9±1.1 cells/acinus vs 4.8±1.2 cells/acinus, P<0.01). The number of KCs in sinusoids was significantly less in the S group than in the N group throughout the observation periods (before ischemia, 19.6±3.3 cells/acinus vs 28.2±4.1 cells/acinus, P<0.01 and 120 min after reperfusion, 29.0±4.3 cells/acinus vs 40.2±3.3 cells/acinus, P<0.01). The blood perfusion of sinusoids 120 min after reperfusion was maintained in the S group more than in the N group. Furthermore, elevation of serum alanine aminotransferase was lower in the S group than in the N group 120 min after reperfusion (99.7±19.8 IU/L vs 166.3±61.1 IU/L, P=0.041), and histological impairment of hepatocyte structure was prevented in the S group. CONCLUSION: Ischemia-reperfusion injury in mild steatotic liver was attenuated compared with normal liver due to the decreased number of KCs and the reduction of the KC-platelet interaction.

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-

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.

Failure of P-selectin blockade alone to protect the liver from ischemia-reperfusion injury in the isolated blood-perfused rat liver

AIM： To determine if blockade of P-selectin in the isolated blood-perfused cold ex vivo rat liver model protects the liver from ischemia-reperfusion injury. METHODS： The effect of P-selectin blockade was assessed by employing an isolated blood-perfused cold ex vivo rat liver with or without P-selectin antibody treatment before and after 6 h of cold storage in University of Wisconsin solution. RESULTS： In our isolated blood-perfused rat liver model, pre-treatment with P-selectin antibody failed to protect the liver from ischemia-reperfusion injury, as judged by the elevated aspartate aminotransferase activity. In addition, P-selectin antibody treatment did not significantly reduced hepatic polymorphonuclear leukocyte accumulation after 120 min of perfusion. Histological evaluation of liver sections obtained at 120 min of perfusion showed significant oncotic necrosis in liver sections of both ischemic control and P-selectin antibody-treated groups. However, total bile production after 120 rain of perfusion was significantly greater in P-selectin antibody-treated livers, compared to control livers. No significant difference in P-selectin and ICAM-1 mRNAs and proteins, GSH, GSSG, and nuclear NF-kB was found between control and P-selectin antibody-treated livers. CONCLUSION： In conclusion, we have shown that blockade of P-selectin alone failed to reduced polymorphonuclear leukocyte accumulation in the liver and protect hepatocytes from ischemia-reperfusion injury in the isolated blood-perfused cold-ex vivo rat liver model.

Hepatic ischemia-reperfusion injury in liver transplant setting:mechanisms and protective strategies

Hepatic ischemia-reperfusion injury is a major cause of liver transplant failure,and is of increasing significance due to increased use of expanded criteria livers for transplantation.This review summarizes the mechanisms and protective strategies for hepatic ischemia-reperfusion injury in the context of liver transplantation.Pharmacological therapies,the use of pre-and post-conditioning and machine perfusion are discussed as protective strategies.The use of machine perfusion offers significant potential in the reconditioning of liver grafts and the prevention of hepatic ischemia-reperfusion injury,and is an exciting and active area of research,which needs more study clinically.

Neutrophil-mediated liver injury during hepatic ischemia-reperfusion in rats

BACKGROUND: Neutrophil plays an important role in hepatic ischemia-reperfusion injury. We investigated neutrophil infiltration in liver tissue, Kupffer cells' role in neutrophil accumulation, and apoptosis and regeneration of hepatocytes in liver ischemia-reperfusion injury. METHODS: Vascular microclamps were placed across the pedicles of the median and left lateral lobes for 90 minutes after 30% hepatectomy with the resection of caudate, right lateral and quadrate lobes and papillary process. Gadolinium chloride (GdCl3) was used to destroy Kupffer cells. Neutrophil activity was inhibited with Urge-8, a monoclonal antibody against neutrophil produced in our laboratory. GdCl3 (10 mg/kg) and Urge-8 (50 mg/kg) were given intravenously in respective groups. Ischemia control, GdCl3 and Urge-8 groups were compared. RESULTS: Following hepatic reperfusion, serum interleukin-8 (IL-8) levels and hepatic neutrophil counts peaked at 3 hours, and peak concentrations of alanine aminotransferase (ALT) occurred at 6 hours. Animals of the control group showed increases in neutrophil infiltration in liver tissue, liver enzyme levels, and apoptosis index of hepatocytes and decreases in overall survival rate and proliferating cell nuclear antigen (PCNA) expression of hepatocytes. The survival rates and PCNA proportion of hepatocytes were higher and the levels of hepatic neutrophil infiltration, liver enzymes, and hepatocyte apoptosis after reperfusion were lower in the GdCl3 and Urge-8 groups than those in the ischemia control group. CONCLUSIONS: Blockades of Kupffer cells' activity and neutrophil infiltration by GdCl3 and Urge-8 eliminate neutrophil-mediated hepatic injury and enhance subsequent hepatic regeneration during liver ischemiareperfusion.

γ-hydroxybutyrate protects the liver from warm ischemia-reperfusion injury in rat

BACKGROUND: Ischemia-reperfusion (I/R) syndrome remains an important clinical consideration in hepatic sur- gery, hemorrhagic shock, and liver transplantation, -y-hy- droxybutyrate (GHB) has been reported to exert protective effects against ischemia-reperfusion injury to various or- gans. To investigate whether GHB protects the liver from warm ischemia-reperfusion injury, we performed this study in rats. METHODS: Thirty male Wistar rats were randomly divided into a sham-operation group, a control group, and three I/R groups pretreated with GHB, GHB plus naloxone or naloxone. After 30 minutes of partial ischemia, followed by 60 minutes of reperfusion in the liver, histomorphological and enzymological changes, lipid peroxidation, apoptosis, and the plasma level of endothelin-1 were observed. RESULTS: I/R increased the serum levels of alanine ami- notransferase, aspartate aminotransferase and lactate dehy- drogenase and the plasma level of endothelin-1 significantly (P<0.01), in addition to increase of apoptotic index (AI) from 0.28%±0.25% to 17.68%±1.91%. The levels of he- patic malondialdehyde were markedly increased, whereas the activities of superoxide dismutase were markedly de- creased. GHB pretreatment prevented the liver from warm ischemia-reperfusion injury significantly, but naloxone par- tially blocked this effect. CONCLUSION: GHB may significantly protect the liver from hepatic warm ischemia-reperfusion injury via several different mechanisms.

Protective effect of pyrrolidine dithiocarbamate on liver injury induced by intestinal ischemia-reperfusion in rats

BACKGROUND: The nuclear translocation of transcription factors may be a critical factor in the intracellular pathway involved in ischemia/reperfusion(I/R) injury. The aim of the study was to evaluate the role of nuclear factor-kappa B (NF-κB) in the pathogenesis of liver injury induced by intestinal ischemia/reperfusion (IIR) and to investigate the effect of pyrrolidine dithiocarbamate (PDTC) on this liver injury. METHODS: Male Wistar rats were divided randomly into three experimental groups (8 rats in each): sham operation group (control group); intestinal/reperfusion group(I/R group): animals received 1-hour of intestinal ischemia and 2-hour reperfusion; and PDTC treatment group (PDTC group): animals that received I/R subject to PDTC treatment (100 mg/kg). The histological changes in the liver and intestine were observed, and the serum levels of tumor necrosis factor-α (TNF-α), alanine aminotransferase (ALT), aspartate aminotransferase (AST), liver superoxide dismutase (SOD), and nitrite/nitrate (NO) were measured. The immunohistochemical expression and Western blot analysis of liver NF-κB and intercellular adhesion molecule-1(ICAM-1) were observed. RESULTS: IIR induced liver injury characterized by the histological changes of liver edema, hemorrhage, polymorphonuclear neutrophil (PMN) infiltration, and elevated serum levels of AST and ALT. The serum TNF-α level was significantly higher than that of the control group(P<0.01) and a high level of liver oxidant product was observed (P<0.01). These changes were parallel to the positive expression of NF-κB and ICAM-1. After the administration of PDTC, the histological changes after liver injury were improved; the levels of SOD and NO in the liver were elevated and reduced, respectively (P<0.01). The expressions of ICAM-1 and NF-κB in the liver were weakened (P<0.01). CONCLUSION: NF-κB plays an important role in the pathogenesis of liver injury induced by HR. PDTC, an agent known to inhibit the activation of NF-κB, can reduce and prevent this injury.

Expression and role of inducible nitric oxide synthase in ischemia-reperfusion liver in rats

OBJECTIVE: To investigate the expression and the role of iNOS expression in hepatic ischemia-reperfusion (L/R) injury. METHODS: Male Wistar rats were subjected to 30-minute hepatic ischemia, then iNOS protein and iNOS mRNA expression in liver tissue was assessed by Western blot and RT-PCR analysis respectively at different time points after reperfusion. The effects of L-NAME (Nω-nitro-L-arginine methyl ester, a nonselective NOS inhibitor) or AE-ITU (aminoethytl-isothiourea, a relative selective inhibitor of iNOS) treatment were also evaluated. RESULTS: High levels of iNOS protein and mRNA expression were detected in the liver tissue subjected to I/R, but not in the sham-operated rats. iNOS protein and iNOS mRNA expression reached a maximum on the first day after reperfusion and decreased later. The levels of iNOS protein and iNOS mRNA disappeared on 7th, 3rd day after reperfusion respectively. The high iNOS expression was correlated with hepatic dysfunction. L-NAME administration worsened hepatic dysfunction induced by hepatic I/R. In contrast, AE-ITU administration showed mild protective effects against hepatic dysfunction induced by hepatic I/R. CONCLUSION: Ischemia-reperfusion may induce or up-regulate the expression of iNOS protein and iNOS mRNA, which is detrimental to hepatic I/R injury.

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.

Histological and biochemical alterations in early-stage lobar ischemia-reperfusion in rat liver

AIM： To investigate the structural and biochemical changes in the early stage of reperfusion in the rat livers exposed to lobar ischemia-reperfusion （IR）. METHODS： The median and left lobes of the liver were subjected to 60 min ischemia followed by 5, 10, 30, 45, 60 and 120 min reperfusion. Blood samples were taken at different time intervals to test enzyme activities and biochemical alterations induced by reperfusion. At the end of each reperfusion period, the animals were killed by euthanasia and tissue samples were taken for histological examination and immunohistochemistry. RESULTS： Cell vacuolation, bleb formation and focal hepatitis were the most important changes occur during ischemia. While some changes including bleb formation were removed during reperfusion, other alterations including portal hepatitis, inflammation and the induction of apoptosis were seen during this stage. The occurrence of apoptosis, as demonstrated by apoptotic cells and bodies, was the most important histological change during reperfusion. The severity of apoptosis was dependent on the time of reperfusion, and by increasing the time of reperfusion, the numbers of apoptotic bodies was significantly enhanced. The amounts of lactate dehydrogenase, alanine aminotransferase, aspartate aminotransfrase, creatinine and urea were significantly increased in serum obtained from animals exposed to hepatic IR. CONCLUSION： Inflammation and subsequent apoptotic cell death were the most important changes in early-stage hepatic reperfusion injury, and the number of apoptotic bodies increased with time of reperfusion.

New drug delivery system for liver sinusoidal endothelial cells for ischemia-reperfusion injury

AIM: To investigate the cytoprotective effects in hepatic ischemia-reperfusion injury, we developed a new formulation of hyaluronic acid(HA) and sphingosine 1-phophate.METHODS: We divided Sprague-Dawley rats into 4 groups: control, HA, sphingosine 1-phosphate(S1P), and HA-S1 P. After the administration of each agent, we subjected the rat livers to total ischemia followed by reperfusion. After reperfusion, we performed the following investigations: alanine aminotransferase(ALT), histological findings, Td T-mediated d UTP-biotin nick end labeling(TUNEL) staining, and transmission electron microscopy(TEM). We also investigated the expressionof proteins associated with apoptosis, hepatoprotection, and S1 P accumulation. RESULTS: S1 P accumulated in the HA-S1 P group livers more than S1 P group livers. Serum ALT levels, TUNEL-positive hepatocytes, and expression of cleaved caspase-3 expression, were significantly decreased in the HA-S1 P group. TEM revealed that the liver sinusoidal endothelial cell(LSEC) lining was preserved in the HA-S1 P group. Moreover, the HA-S1 P group showed a greater increase in the HO-1 protein levels compared to the S1 P group.CONCLUSION: Our results suggest that HA-S1 P exhibits cytoprotective effects in the liver through the inhibition of LSEC apoptosis. HA-S1 P is an effective agent for hepatic ischemia/reperfusion injury.

The effects of ischemia-reperfusion injury and hepatic artery ischemia on CD14 expression in canine auto-transplantation livers

Objective： To study the effect of ischemia-reperfusion injury（IRI） and hepatic artery ischemia（HAI） on CD14 expression in canine auto-transplantation livers. Methods：Liver orthotopic auto-transplantation models were applied with 30 healthy male Xi＇ an canines which were randomly divided into a control group, simultaneous reperfusion（SR） group and HAI group, CD14 protein expression, Malonaldehyde （MDA） Contents in hepatic tissues and ALT values in serum were detected, and the pathological changes of hepatic tissues was investigated under the light microscopy. Results：The level of CD14 protein expression in SR and HAI group tended to be time-dependent and both higher than controls with statistical significance（P 〈 0.01）; The peak values of these two groups both occurred at 4 h, but the level in HAI group （11.94 ± 0.43） was evidently higher than that in SR group（3.04 ± 0.34）. MDA contents in liver tissue, ALT values in serum and pathological changes showed the same changing tendency as CD 14 expression. Conclusion：（1） Up-regulation of CD14 expression may be the receptor-mechanism of Kupffer cells（KCs） activation in liver transplantation. （2） HAI can upregulate CD14 expression after portal vein reperfusion, improve the activity of KCs further more, increase OFRs production and cooperate with portal reperfusion, and finally aggravate the grafts injury.

Effect of liver regeneration after partial hepatectomy and ischemia-reperfusion on expression of growth factor receptors

AIM： To investigate the effects of experimental partial hepatectomy and normothermic ischemia-reperfusion damage on the time course of the expression of four different growth factor receptors in liver regeneration. This is relevant due to the potential therapeutic use of growth factors in stimulating liver regeneration. METHODS： For partial hepatectomy （PH） 80% of the liver mass was resected in Sprague Dawley rats. Ischemia and reperfusion （I/R） were induced by occlusion of the portal vein and the hepatic artery for 15 min. The epidermal growth factor receptor, hepatic growth factor receptor, fibroblast growth factor receptor and tumour necrosis factor receptor-1 were analysed by immunohistochemistry up to 72 h after injury. Quantitative RT-PCR was performed at the time point of minimal receptor expression （24 h）. RESULTS： In immunohistochemistry, EGFR, HGFR, FGFR and TNFR1 showed biphasic kinetics after partial hepatectomy with a peak up to 12 h, a nadir after 24 h and another weak increase up to 72 h. During liver regeneration, after ischemia and reperfusion, the receptor expression was lower; the nadir at 24 h after reperfusion was the same. To evaluate whether this nadir was caused by a lack of mRNA transcription, or due to a posttranslational regulation, RT-PCR was performed at 24 h and compared to resting liver. In every probe there was specific mRNA for the receptors. EGFR, FGFR and TNFR1 mRNA expression was equal or lower than in resting liver, HGFR expression after I/R was stronger than in the control. CONCLUSION： At least partially due to a post-transcriptional process, there is a nadir in the expression of the analysed receptors 24 h after liver injury. Therefore, a therapeutic use of growth factors to stimulate liverregeneration 24 h after the damage might be not successful.

Interaction of L-Arginine-methyl ester and Sonic hedgehog in liver ischemia-reperfusion injury in the rats

AIM： To investigate the role of Sonic hedgehog （Shh） on the course of liver ischemia and reperfusion （I/R） in rats, and the interaction between treatment with nitric oxide donor L-Arginine-methyl ester （L-Arg） and up-regulation of Shh expression.METHODS： A total of 30 male Sprague-Dawley rats weighing 220-240 g were used in this study. Shamcontrol group （G1, n = 10）： a sham operation was performed （except for liver I/R）. I/R-untreated group （G2, n = 10）： rats underwent liver ischemia for 1 h followed by reperfusion for 45 min. I/R-L-Arg group （G3, n = 10）： after performing the same surgical procedure as in group 2, animals were treated with L-Arg. Liver tissues were taken for determination of malondialdehyde （MDA） levels, and biochemical and histological evaluations were made.RESULTS： Plasma alanine aminotransferase （ALT）, aspartate aminotransferase （AS-T）, lactate dehydrogenase （LDH） and T-glutamyltranspeptidase （GGT） activities were higher in group 2 than in group 3. MDA values and the hepatic injury score decreased in the L-Arg treated group compared to the I/R-untreated group. In group 2, the hepatoo/tes were swollen with marked vacuolization. Group 3 rats showed well-preserved liver parenchyma, with hepatocytes extending from the central vein. The morphology of the hepatocytes and the sinusoidal structures was normal, without any signs of congestion. Mild Shh positive immunostaining was detected in group 2 animals. The expression of immunoreactive cells was increased markedly in liver tissue from I/R-L-Arg rats.CONCLUSION： Our findings suggest that Shh molecules are critical factors in the pathophysiology of inflammatory liver injury induced by I/R. In addition, NO plays an important role in the immunohistochemical expression of these molecules.

Interferon-γpriming enhances the therapeutic effects of menstrual blood-derived stromal cells in a mouse liver ischemia-reperfusion model

BACKGROUND Mesenchymal stem cells(MSCs)have been used in liver transplantation and have certain effects in alleviating liver ischemia-reperfusion injury(IRI)and regulating immune rejection.However,some studies have indicated that the effects of MSCs are not very significant.Therefore,approaches that enable MSCs to exert significant and stable therapeutic effects are worth further study.AIM To enhance the therapeutic potential of human menstrual blood-derived stromal cells(MenSCs)in the mouse liver ischemia-reperfusion(I/R)model via interferon-γ(IFN-γ)priming.METHODS Apoptosis was analyzed by flow cytometry to evaluate the safety of IFN-γpriming,and indoleamine 2,3-dioxygenase(IDO)levels were measured by quantitative real-time reverse transcription polymerase chain reaction,western blotting,and ELISA to evaluate the efficacy of IFN-γpriming.In vivo,the liver I/R model was established in male C57/BL mice,hematoxylin and eosin and TUNEL staining was performed and serum liver enzyme levels were measured to assess the degree of liver injury,and regulatory T cell(Treg)numbers in spleens were determined by flow cytometry to assess immune tolerance potential.Metabolomics analysis was conducted to elucidate the potential mechanism underlying the regulatory effects of primed MenSCs.In vitro,we established a hypoxia/reoxygenation(H/R)model and analyzed apoptosis by flow cytometry to investigate the mechanism through which primed MenSCs inhibit apoptosis.Transmission electron microscopy,western blotting,and immunofluorescence were used to analyze autophagy levels.RESULTS IFN-γ-primed MenSCs secreted higher levels of IDO,attenuated liver injury,and increased Treg numbers in the mouse spleens to greater degrees than untreated MenSCs.Metabolomics and autophagy analyses proved that primed MenSCs more strongly induced autophagy in the mouse livers.In the H/R model,autophagy inhibitors increased the level of H/R-induced apoptosis,indicating that autophagy exerted protective effects.In addition,primed MenSCs decreased the level of H/R-induced apoptosis via IDO and autophagy.Further rescue experiments proved that IDO enhanced the protective autophagy by inhibiting the mammalian target of rapamycin(mTOR)pathway and activating the AMPK pathway.CONCLUSION IFN-γ-primed MenSCs exerted better therapeutic effects in the liver I/R model by secreting higher IDO levels.MenSCs and IDO activated the AMPK-mTOR-autophagy axis to reduce IRI,and IDO increased Treg numbers in the spleen and enhanced the MenSC-mediated induction of immune tolerance.Our study suggests that IFN-γ-primed MenSCs may be a novel and superior MSC product for liver transplantation in the future.