Reduction of ischemia reperfusion injury after liver resection and hepatic inflow occlusion by α-Iipoic acid in humans

AIM: To evaluate the protective effects of preconditioning by alpha-lipoic acid (LA) in patients undergoing hepatic resection under inflow occlusion of the liver. METHODS: Twenty-four patients undergoing liver resection for various reasons either received 600 mg LA or NaCl 15 min before transection performed under inflow occlusion of the liver. Blood samples and liver wedge biopsy samples were obtained after opening of the abdomen immediately after inflow occlusion of the liver, and 30 min after the end of inflow occlusion of the liver. RESULTS: Serum levels of aspartate transferase and alanine transferase were reduced at all time points in patients who received LA in comparison to those who received NaCL. This was accompanied by reduced histomorphological features of oncosis. We observed TUNEL-positive hepatocytes in the livers of the untreated patients, especially after 30 min of ischemia. LA attenuated this increase of TUNEL-positive hepatocytes. Under preconditioning with LA, ATP content was significantly enhanced after 30 min of ischemia and after 30 min of reperfusion. CONCLUSION: This is the first report on the potential for LA reducing ischemia/reperfusion injury (IRI) of the liver in humans who were undergoing liver surgery. Beside its simple and rapid application, side effects did not occur. LA might therefore represent a new strategy against hepatic IRI in humans.     

Effect of tetramethylpyrazine on P-selectin and hepatic／rena ischemia and reperfusion injury in rats

AIM: To investigate the effect of tetramethylpyrazine on hepatic/renal ischemia and reperfusion injury in rats. METHODS: Hepatic/renal function, histopathological changes, and hepatic/renal P-selectin expression were studied with biochemical measurement and immunohistochemistry in hepatic/renal ischemia and reperfusion injury in rat models. RESULTS: Hepatic/renal insufficiency and histopathological damage were much less in the tetramethylpyrazine-treated group than those in the saline-treated groups. Hepatic/renal P-selectin expression was down regulated in the tetramethylpyrazine-treated group. CONCLUSION: P-selectin might mediate neutrophil infiltration and contribute to hepatic/renal ischemia and reperfusion injury. Tetramethylpyrazine might prevent hepatic/renal damage induced by ischemia and reperfusion injury through inhibition of P-selectin.     

Modulation of liver oxidant-antioxidant system by ischemic preconditioning during ischemia／reperfusion injury in rats

AIM: To investigate effects of ischemic pre-conditioning on the liver endogenous oxidant-antioxidant system during ischemia/reperfusion injury. METHODS: Twenty-four male Sprague-Dawley rats were randomly divided into sham-operated (Sham), ischemia/ reperfusion (I/R), ischemic pre-conditioning plus ischemia/ reperfusion (IPC) groups. Serum ALT, AST and hyaluronic acid levels were assayed and pathologic alterations observed. Liver malondialdehyde (MDA) contents, endogenous antioxidant enzymes, superoxidase dismutase (SOD), catalase (CAT), gultathionine peroxidase (GSH-Px) activities, neutrophils accumulation marker, myeloperoxidase (MPO) activities were measured respectively. RESULTS: Compared with I/R group, sinusoidal endothelial cells as well as hepatocytes damages, as assessed biochemically and histochemically, were improved significantly in IPC group; neutrophils infiltration was also markedly reduced. In IPC group, liver peroxidation, as measured by MDA contents, was significantly decreased when compared with I/R group; endogenous antioxidant enzymes, SOD, CAT and GSH-Px activities were markedly higher than that in I/R group. CONCLUSION: Ischemic pre-conditioning exerts protective effects on both hepatic sinusoidal endothelial cells and hepatocytes during liver I/R injury. Its mechanisms may involve dimunition of neutrophils infiltration and modulation of the imbalance of endogenous oxidant-antioxidant system in the organism.     

The relationship between activation of TLR4 and partial hepatic ischemia/reperfusion injury in mice

BACKGROUND: Toil-like receptors (TLRs) are a group of evolutionarily conserved pattern recognition receptors involved in the activation of the immune system in response to various pathogens. In this study, we elucidated the relationship between activation of TLR4 and liver injury in partial hepatic ischemia/reperfusion (I/R) injury in mice. METHODS: BALB/c mice were used in a model of partial hepatic I/R injury, and the changes of TLR4 gene expression in ischemic liver lobes were detected with real-time polymerase chain reaction (RT-PCR). The levels of plasma ALT and endotoxin in the portal vein were measured. TLR4-deficient mice (C3H/Hej) and wild type mice (C3H/Heouj) were used in a model of I/R injury; liver function impairment and the level of serum TNF-α were observed. RESULTS: After one hour ischemia, the expression of TLR4 mRNA increased at the 1st, 3rd hour of reperfusion, indicating the value of △Ct(1st hour: 1.21±0.87vs. 5.85±1.07, t=13.72, P<0.01; 3rd hour: 0.85±0.92vs. 6.11±1.24, t=16.33, P<0.01). No endotoxemia developed in every group of mice. At the 3rd hour of reperfusion, the level of serum TNF-α was significantly higher than that of sham group (Hej: 152±43 pg/ml vs. 18±10pg/ml, t=5.26, P<0.01; Heouj: 249±52pg/ml vs. 25±13 pg/ml, t=7.24, P<0.01). At the 1st, 3rd hour reperfusion, the level of plasmid ALT in Hej mice was lower than that in Heouj mice (1st hour 662±106 U/Lvs. 1216±174 U/L, t=4.21, P<0.01; 3rd hour 1145±132U/L vs. 29584±187 U/L, t=13.72, P<0.01). The level of serum TNF-αwas lower than that in Heouj mice (1524.43 U/L vs. 2494±52 U/L, t=3.94, P<0.01) at the 3rd hour reperfusion. CONCLUSION: TLR4 activation causes partial hepatic I/R injury through release of TNF-α.     

Does liver cirrhosis have an impact on the results of different hepatic inflow occlusion methods in laparoscopic liver resection? a propensity score analysis

BackgroundFew studies have analyzed the impact of liver cirrhosis on different hepatic inflow occlusion methods in laparoscopic liver resection (LLR). Intermittent Pringle (IP) was compared to continuous hemihepatic vascular inflow occlusion (CHVIO) in LLR in patients with or without cirrhosis.MethodsPatients who underwent LLR at the West China Hospital of Sichuan University form January 2015 to October 2017 were grouped according to occlusion methods and severity of cirrhosis. A matched propensity score analysis was performed.ResultsAmong patients without cirrhosis, there were no significant differences in blood loss (238 ± 30 ml VS 265 ± 46 ml, P = 0.653), operative time (228 ± 9 min VS 265 ± 20 min, P = 0.437) or other postoperative results between the IP and CHVIO groups after propensity score matching. Among patients with cirrhosis, blood loss (279 ± 24 ml VS 396 ± 35 ml, P = 0.012) and operative time (237 ± 11 min VS 285 ± 24 min, P = 0.041) were significantly lower in the IP group, while postoperative liver function did not significantly differ between the two groups after propensity score matching.ConclusionsIn patients without cirrhosis, IP is as efficient and as safe as CHVIO in cirrhotic patients. IP offers the advantages of shorter operative time and less blood loss and does not result in worse postoperative liver function.     

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±161.3 u/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.     

Effect of N—desulfated heparin on hepatic／renal ischemia reperfusion injury in rats

AIM：To invesigate the effect of N-desulfated heparin on hepatic/renal ischemia and reperfusion injury in rats.METHODS:Using rat models of 60minutes hepatic of renal ischemia followed by 1h,3h,6hand24h reperfusion.animals were randomly divided into following groups,the sham operated controls,ischemic group receiving only normal saline,and treated group receiving N-desulfated heparin at a dose of 12mg/kg at 5minutes before reperfusion.P-selectin expression was detected in hepatic/renal tissues with immunohistochemistry method.RESULTS:P-selectin expression,serumALT,AST,BUNand Cr levels were significantly increased during60minute ischemia and 1h,3h,6hand24hreperfusion.while the increment was significantly inhibited,and hepatic/renal pathology observed by light microscopy was remarkably improved by treatment with the N-desulfated heparin.Furthermore.the heparin was found no effects on PT and KPTT.CONCLUSION:P-selectin might mediate neutrophil infitration and contribute to hepatic/renai ischemia and reperfusion.THe N-desulfated heparin might prevent hepatic/renal admage induced by ischemia and reperfusion injury without significant anticoagulant activity.     

Melatonin abates liver ischemia/reperfusion injury by improving the balance between nitric oxide and endothelin

Introduction Melatonin (5-methoxy-N-acetyltryptamine) is a naturally occurring hormone derived from the amino acid tryptophan andproduced mainly by the pineal gland (pinealocytes) in the brain as well as in the retina and gastrointestinal tract. Although the major role of melatonin is in the sleep-wake cycle through its circadian fluctuation, a large body of literature has recently demonstrated that melatonin also exerts complex physiological and pharmacological effects on multiple systems and…     

TNFα in ischemia/reperfusion injury and heart failure

Abstract. During myocardial ischemia, both the myocardial and serum TNF concentrations are rapidly increased within the area at risk. With prolongation of ischemia and development of cardiomyocyte necrosis, the TNF concentration increases also in the surrounding viable portions of the myocardium. Indeed, in the scenario of myocardial ischemia/reperfusion, treatment with TNF antibodies reduced the extent of myocardial infarction in rabbits and attenuated the contractile dysfunction following microembolization in dogs. In the latter studies, the serum TNF concentration remained unaltered thereby supporting the notion of a direct action of TNF at the level of cardiomyocytes during ischemia/reperfusion.In heart failure, the serum TNF concentration is also increased, and in patients with advanced heart failure the serum TNF concentration is an independent predictor of mortality. The origin of the increased serum TNF concentration is not clearly identied yet, but TNF derived from the heart and peripheral organs contributes to the increased serum TNF concentration. Treatment with TNF antibodies in the clinical scenario, however, did not improve the prognosis of heart failure patients.     

Role of nitric oxide and peroxynitrite anion in lung injury induced by intestinal ischemia－reperfusion in rats

AIM: To evaluate effects of nitric oxide (NO) and peroxynitrite anion (ONOO-) on lung injury following intestinal ischemia-reperfusion (IR) in rats. METHODS: A rat model of intestinal ischemia was made by clamping superior mesenteric artery and lung injury was resulted from reperfusion. The animals were randomly divided into 3 groups: sham operation (Sham), 2 h ischemia followed by 2 h reperfusion (IR) and IR pretreated with aminoguanidine (AG) - an inhibitor of inducible NO synthase (iNOS) 15 minutes before reperfusion (IR+AG). The lung malondialdehyde (MDA) and nitrate/nitrite (NO2/NO3)contents and morphological changes were examined.Western blot was used to detect the iNOS protein expression.Immunohistochemical staining was used to determine the change of nitrotyrosine (NT)- a specific "footprint" of ONOO-. RESULTS: The morphology revealed evidence for lung edema, hemorrhage and polymorphonuclear sequestration after intestinal IR. Compared with sham group, lung contents of MDA and NO2-/NO3- in IR group were significantly increased (12.00±2.18 vs23.44±1.25 and 76.39±6.08 vs140.40±4.34,P＜0.01) and the positive signals of iNOS and NT were also increased in the lung. Compared with IR group, the contents of MDA and NO2/NO3 in IR+AG group were significantly decreased (23.44±1.25 vs14.66±1.66 and 140.40±4.34 vs 80.00±8.56, P＜0.01) and NT staining was also decreased. CONCLUSION: Intestinal IR increases NO and ONOO production in the lung, which may be involved in intestinal IR-mediated lung injury.     

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

AIM: To evaluate the protective effect of NF-κB 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-κB decoy ODNs or scrambled ODNs. NF-κB 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-κB 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-κB activation in liver graft was induced in a time-dependent manner, and NF-κB remained activated for 16 h after graft reperfusion. NF-κB activation in liver graft was significant at 2 to 8 h and slightly decreased at 16 h after graft reperfusion. Administration of NF-κB decoy ODNs significantly suppressed NF-κB activation as well as mRNA expression of TNF-α, IFN-γ and ICAM-1 in the liver graft. The hepatic NF-κB DNA binding activity [presented as integral optical density (IOD) value] in the NF-κB 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 [presented as percent of p-actin mRNA (%)] in the NF-κB 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-a mRNA, 5.58±2.16 vs 50.46±9.35 and 6.47±2.53 vs 69.72±13.41 for hepatic IFN-y 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-κB 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 IFN-γ 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-κB decoy ODNs, the hepatic MPO content (A655) and serum ALT level (IU/L) in the NF-κB 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-κB decoy ODNs protects against I/R injury in liver graft by suppressing NF-κB activation and subsequent expression of proinflammatory mediators.     

Characterization of the cardiac succinylome and its role in ischemia–reperfusion injury

Succinylation refers to modification of lysine residues with succinyl groups donated by succinyl-CoA. Sirtuin5 (Sirt5) is a mitochondrial NAD⁺-dependent deacylase that catalyzes the removal of succinyl groups from proteins. Sirt5 and protein succinylation are conserved across species, suggesting functional importance of the modification. Sirt5 loss impacts liver metabolism but the role of succinylation in the heart has not been explored. We combined affinity enrichment with proteomics and mass spectrometry to analyze total succinylated lysine content of mitochondria isolated from WT and Sirt5^−/− mouse hearts. We identified 887 succinylated lysine residues in 184 proteins. 44 peptides (5 proteins) occurred uniquely in WT samples, 289 (46 proteins) in Sirt5^−/− samples, and 554 (133 proteins) were common to both groups. The 46 unique proteins in Sirt5^−/− heart participate in metabolic processes such as fatty acid β-oxidation (Eci2) and branched chain amino acid catabolism, and include respiratory chain proteins (Ndufa7, 12, 13, Dhsa). We performed label-free analysis of the peptides common to WT and Sirt5^−/− hearts. 16 peptides from 9 proteins were significantly increased in Sirt5^−/− by at least 30%. The adenine nucleotide transporter 1 showed the highest increase in succinylation in Sirt5^−/− (108.4 fold). The data indicate that succinylation is widespread in the heart and enriched in metabolic pathways. We examined whether the loss of Sirt5 would impact ischemia–reperfusion (I/R) injury and we found an increase in infarct size in Sirt5^−/− hearts compared to WT littermates (68.5⁺/₋ 1.1% Sirt5^−/− vs 39.6⁺/⁻ 6.8% WT) following 20 min of ischemia and 90-min reperfusion. We further demonstrate that I/R injury in Sirt5^−/− heart is restored to WT levels by pretreatment with dimethyl malonate, a competitive inhibitor of succinate dehydrogenase (SDH), implicating alteration in SDH activity as causative of the injury.     

Thioredoxin-interacting protein and myocardial mitochondrial function in ischemia–reperfusion injury

Cellular metabolism and reactive oxygen species (ROS) formation are interrelated processes in mitochondria and are implicated in a variety of human diseases including ischemic heart disease. During ischemia, mitochondrial respiration rates fall. Though seemingly paradoxical, reduced respiration has been observed to be cardioprotective due in part to reduced generation of ROS. Enhanced myocardial glucose uptake is considered beneficial for the myocardium under stress, as glucose is the primary substrate to support anaerobic metabolism. Thus, inhibition of mitochondrial respiration and uncoupling oxidative phosphorylation can protect the myocardium from irreversible ischemic damage. Growing evidence now positions the TXNIP/thioredoxin system at a nodal point linking pathways of antioxidant defense, cell survival, and energy metabolism. This emerging picture reveals TXNIP’s function as a regulator of glucose homeostasis and may prove central to regulation of mitochondrial function during ischemia. In this review, we summarize how TXNIP and its binding partner thioredoxin act as regulators of mitochondrial metabolism. While the precise mechanism remains incompletely defined, the TXNIP–thioredoxin interaction has the potential to affect signaling that regulates mitochondrial bioenergetics and respiratory function with potential cardioprotection against ischemic injury.