M. A. Zaouali

How Institut Georges Lopez preservation solution protects nonsteatotic and steatotic livers against ischemia-reperfusion injury.

The Institut Georges Lopez preservation solution (IGL-1) is a serum-free organ preservative that has been shown to protect steatotic livers against hepatic ischemia-reperfusion injury. Although several hypotheses have been proposed to explain the graft protection mechanisms induced by IGL-1 solution, they have not been fully investigated. This review assessed possible IGL-1 mechanisms responsible for the increased liver tolerance of ischemia-reperfusion injury with special emphasis on vasodilatator mediators such as nitric oxide, on oxidative stress prevention, on protection against mitochondrial damage, and finally on induction of cytoprotective factors.

Relevance of Epidermal Growth Factor to Improve Steatotic Liver Preservation in IGL-1 Solution

AIM Static preservation solution is critical for liver graft outcomes, especially when steatosis is present. Institut Georges Lopez (IGL)-1 solution protects fatty livers effectively against cold ischemia reperfusion injury. Its benefits are mediated by nitric oxide and prevention of oxidative stress. The supplementation of IGL-1 with epidermal growth factor (EGF) enhances steatotic graft preservation by increasing adenosine triphosphate content, thereby mitigating oxidative stress and mitochondrial damage. METHODS After steatotic livers were preserved for 24 hours in IGL-1 solution with or without EGF supplements, they were perfused ex vivo for 2 hours at 37°C. The benefits of EGF were assessed by evidences of hepatic damage and function--transaminases, bile production, and flow rate--as well as by other factors presumably associated with the poor tolerance of fatty livers toward cold ischemia-reperfusion injury (IRI)--energy metabolism, mitochondrial damage, oxidative stress, eNOS activity and proinflammatory interleukin (IL) beta content. RESULTS Steatotic livers preserved in IGL-1 solutions supplemented with EGF (10 μg/L) showed lower transaminase levels, greater bile production, and ameliorated flow rates when compared to IGL-1 alone. In addition, energy metabolism deterioration, mitochondrial damage, oxidative stress, and cytokine IL-1 beta release were prevented. CONCLUSION EGF addition to IGL-1 increased fatty liver graft preservation, thereby reducing steatotic liver damage against cold IRI.

Effects of trimetazidine on the Akt/eNOS signaling pathway and oxidative stress in an in vivo rat model of renal ischemia-reperfusion

Abstract Renal ischemia reperfusion (I/R) injury, which occurs during renal surgery or transplantation, is the major cause of acute renal failure. Trimetazidine (TMZ), an anti-ischemic drug, protects kidney against the deleterious effects of I/R. However its protective mechanism remains unclear. The aim of this study is to examine the relevance of Akt, endothelial nitric oxide synthase (eNOS), and hypoxia inducible factor-1α (HIF-1α) on TMZ induced protection of kidneys against I/R injury. Wistar rats were subjected to 60 min of warm renal ischemia followed by 120 min of reperfusion, or to intraperitoneal injection of TMZ (3 mg/kg) 30 min before ischemia. In sham operated group renal pedicles were only dissected. Compared to I/R, TMZ treatment decreased lactate dehydrogenase (845 ± 13 vs. 1028 ± 30 U/L). In addition, creatinine clearance and sodium reabsorption rates reached 105 ± 12 versus 31 ± 11 μL/min/g kidney weight and 95 ± 1 versus 68 ± 5%, respectively. Besides, we noted a decrease in malondialdehyde concentration (0.33 ± 0.01 vs. 0.59 ± 0.03 nmol/mg of protein) and an increase in glutathione concentration (2.6 ± 0.2 vs. 0.93 ± 0.16 µg GSH/mg of protein), glutathione peroxidase (95 ± 4 vs. 61 ± 3 µg GSH/min/mg of protein), and superoxide dismutase (25 ± 3 vs. 11 ± 2 U/mg of protein) and catalase (91 ± 12 vs. 38 ± 9 μmol/min/mg of protein) activities. Parallely, we noted a significant increase in p-Akt, eNOS, nitrite and nitrate (18 ± 2 vs. 8 ± 0.1 pomL/mg of protein), HIF-1α (333 ± 48 vs. 177 ± 14 µg/mg of protein) and heme oxygenase-1 (HO-1) levels regarding I/R. TMZ treatment improves renal tolerance to warm I/R. Such protection implicates an activation of Akt/eNOS signaling pathway, HIF-1α stabilization and HO-1 activation.

Zinc mitigates renal ischemia-reperfusion injury in rats by modulating oxidative stress, endoplasmic reticulum stress, and autophagy

Oxidative stress is a major factor involved in the pathogenesis of renal ischemia/reperfusion (I/R). Exogenous zinc (Zn) was suggested as a potent antioxidant; however, the mechanism by which it strengthens the organ resistance against the effects of reactive oxygen species (ROS) is not yet investigated. The present study aims to determine whether acute zinc chloride (ZnCl2) administration could attenuate endoplasmic reticulum (ER) stress, autophagy, and inflammation after renal I/R. Rats were subjected to either sham operation (Sham group, n = 6), or 1 hr of bilateral ischemia followed by 2 hr of reperfusion (I/R groups, n = 6), or they received ZnCl2 orally 24 hr and 30 min before ischemia (ZnCl2 group, n = 6). Rats were subjected to 1 hr of bilateral renal ischemia followed by 2 hr of reperfusion (I/R group, n = 6). Our results showed that ZnCl2 enhances renal function and reduces cytolysis (p < 0,05). In addition, it increased significantly the activities of antioxidant enzymes (SOD, CAT, and GPX) and the level of GSH in comparison to I/R (p < 0,05). Interestingly, ZnCl2 treatment resulted in significant decreased ER stress, as reflected by GRP78, ATF‐6,p‐eIF‐2α, XPB‐1, and CHOP downregulaion. Rats undergoing ZnCl2 treatment demonstrated a low expression of autophagy parameters (Beclin‐1 and LAMP‐2), which was correlated with low induction of apoptosis (caspase‐9, caspase‐3, and p‐JNK), and reduction of inflammation (IL‐1ß, IL‐6, and MCP‐1) (p < 0,05). In conclusion, we demonstrated the potential effect of Zn supplementation to modulate ER pathway and autophagic process after I/R.

Effects of Nitrite Addition to IGL-1 Solution on Rat Liver Preservation.

BACKGROUND The ability of nitrite to provide protection following ischemia/reperfusion (I/R) has been demonstrated, but its mechanism is still poorly understood. This study aimed to determine the optimal nitrite concentration to add into Institut Georges Lopez (IGL-1) storage solution and to assess its effect on antioxidant enzymes and autophagy. MATERIAL AND METHODS Livers from Sprague-Dawley rats were conserved in IGL-1 for 24 hours at 4°C or in IGL-1 enriched with nitrite at 50, 500 and 1,000 nM, respectively, before being perfused ex-vivo at 37 °C for 120 minutes. Sham livers were perfused ex vivo without cold preservation. RESULTS All biological and functional parameters of the preserved livers were significantly impaired as compared to shams. Interestingly, the supplementation of nitrite to IGL-1 protected the liver from I/R injury. Among the doses of nitrite evaluated, the 50 nM was proved efficient: it significantly reduced cytolysis, mitochondrial damage, and lipid peroxidation, and enhanced antioxidant enzyme activity (superoxide dismutase, catalase, and glutathione peroxidase activity) and hepatic function parameters (portal resistance, bile flow, and bromosulfophthalein clearance). In addition, increased levels of the autophagy parameters were observed when 50 nM of nitrite were added to IGL-1 solution, but this effect disappeared completely with higher concentrations of nitrite. CONCLUSIONS It seems that 50 nM of nitrite added to IGL-1 is the optimal concentration able to maintain cell integrity and hepatic function through autophagy induction and oxidative stress prevention.

The effect of zinc acexamate on oxidative stress, inflammation and mitochondria induced apoptosis in rat model of renal warm ischemia

AIM Zinc has proved its efficacy in many models of ischemia reperfusion (I/R) injury. In this study, we used zinc acexamate (ZAC) as an exogenous source of zinc against renal I/R injury and we investigated whether its protective effects are mediated by the decrease of oxidative stress, inflammation, and mitochondria induced-apoptosis. METHODS Rats were orally pretreated with vehicle or ZAC (10 or 100 mg/kg) 24 h and 30 min prior to 1 h of bilateral renal warm ischemia and 2 h of reperfusion. RESULTS Our data showed that 10 mg/kg of ZAC, but not 100 mg/kg, improved renal architecture and function. Also, the low dose of ZAC up-regulated antioxidant enzymes activities and glutathione level and decreased lipids and proteins oxidation. Interestingly, the use of ZAC resulted in a significant reduce of pro-inflammatory cytokines (IL-1ß, IL-6 and MCP-1), enhanced mitochondria integrity and decreased expression of the pro-apoptotic protein caspase-9. CONCLUSION We conclude that renal I/R induced oxidative stress, inflammation and apoptosis and that the use of ZAC at 10 mg/kg, but not 100 mg/kg, protects rat kidneys from I/R injury by down-regulating these processes.

Olprinone protects liver from ischemia reperfusion injury through oxidative stress prevention and protein kinase Akt activation

Liver ischemia-reperfusion (IR) injury is inevitable in surgical procedures such as hepatic resection and liver transplantation. It represents a leading cause of liver graft dysfunction and primary nonfunction after transplantation. Phosphodiesterase (PDE) inhibitors are emerging as effective drugs able to reduce IR damage. The aim of this study was to investigate the effect of selective PDE-3 inhibitor olprinone (Olp) against liver IR injury. Male Wistar rats were subjected to 1 h of partial warm ischemia (70%) followed by 6 h of reperfusion. Before ischemia, rats were treated with saline (IR group), Olp (Olp group), or Olp with Akt inhibitor LY294002 (Olp plus LY group). After reperfusion, hepatic injury (transaminase activities), mitochondrial damage (glutamate dehydrogenase activity), oxidative stress (malondialdehyde and glutathione concentrations and catalase and superoxide dismutase activities), and protein kinase Akt activation were evaluated. Rat treatment with Olp reduced liver injury, prevented mitochondrial damage, decreased lipid peroxidation, and enhanced antioxidant enzymes. Also, Olp induced a significant activation in protein kinase Akt. Inhibition of Akt with LY294002 abolished all of the protective effects of Olp. In conclusion, Olp treatment may be an effective strategy in reducing liver IR injury through oxidative stress prevention and Akt activation.

Nitrite enhances liver graft protection against cold ischemia reperfusion injury through a NOS independent pathway

ABSTRACT Introduction: Nitrite has been found to protect liver graft from cold preservation injury. However, the cell signaling pathway involved in this protection remains unclear. Here, we attempt to clarify if the NOS pathway by using the NOS inhibitor, L-NAME (L-NG-Nitroarginine methyl ester). Animals and methods: Rat livers were conserved for 24 h at 4°C in (IGL-1) solution enriched or not with nitrite at 50 nM. In a third group, rats were pretreated with 50 mg/kg of L-NAME before their liver procurement and preservation in IGL-1 supplemented with nitrite (50 nM) and L-NAME (1 mM). After 24 h of cold storage, rat livers were ex-vivo perfused at 37°C during 2 h. Control livers were perfused without cold storage. Results: Nitrite effectively protected the rat liver grafts from the onset of cold I/R injury. L-NAME treatment did not abolish the beneficial effects of nitrite. Liver damage, protein oxidation and lipid peroxidation remained at low levels in both nitrite-treated groups when compared to IGL-1 group. Antioxidant enzyme activities and functional parameters were unchanged after NOS inhibition. Conclusion: Despite NOS inhibition by L-NAME, nitrite can still provide hepatic protection during cold I/R preservation. This suggests that nitrite acts through a NOS-independent pathway.

171 MELATONIN IS A SUITABLE THERAPEUTIC STRATEGY TO PROTECTS STEATOTIC LIVERS IN MAJOR HEPATECTOMY UNDER ISCHEMIA-REFERFUSION: A ROLE FOR ER STRESS AND AUTOPHAGY

171 HISTONE DEACETYLASE INHIBITOR ALLEVIATED LIVER ISCHEMIA REPERFUSION INJURY BY HEME OXYGENASE-1-MEDIATED ANTI-INFLAMMATORY MECHANISM H. Li, L. Zhang, R. Jiang, H. Yuan, X. Yi, J. Wan. Chongqing Key Laboratory of Biochemistry and Molecular Pharmacology, Department of Pathophysiology, Laboratory of Stem Cell and Tissue Engineering, Department of Pharmacology, Chongqing Medical University, Chongqing, China E-mail: wanjingyuan2001@yahoo.com.cn

ISCHEMIC POST-CONDITIONING PROTECTS KIDNEY FROM ISCHEMIA/REPERFUSION INJURY THROUGH ATTENUATION OF ENDOPLASMIC RETICULUM STRESS: 1361

A. Mahfoudh-Boussaid1, M.A. Zaouali2, J. Rosello-catafau3, D. Saidane-Mosbahi4, A. Miled5, S. Ghoul-Mezgar6, H. Ben Abdennebi7 1, Faculty of pharmacy, Monastir/TUNISIA, 2Experimental Pathology, IIBB-CSIC, Barcelona/SPAIN, 3, Unitat de Transplantament de fetge i viabilitat de l’empelt, Institut d ́Investigacions Biomèdiques August Pi i Sunyer-CIBERehd, barcelona/SPAIN, 4Human Physiology, Faculty of pharmacy, Monastir/TUNISIA, 5Biochemistry, Faculty of pharmacy, Monastir/TUNISIA, 6Histology, Faculty of pharmacy, Monastir/ TUNISIA, 7Humane Physiology, Faculty of pharmacy, Monastir/ TUNISIA