Ismail Ben Mosbah

Preservation of Steatotic Livers in IGL-1 Solution

A new Institut Georges Lopez (IGL‐1) solution was used to preserve steatotic livers. Steatotic (obese [Ob]) and nonsteatotic (lean [Ln]) livers from Zücker rats (n = 16, 8 Ln and 8 Ob) were preserved for 24 hours at 4°C in University of Wisconsin (UW) or IGL‐1 solution, respectively, and then perfused ex vivo for 2 hours at 37°C. Additionally, Ob and Ln livers (n = 16, 8 Ln and 8 Ob) were preserved in IGL‐1 plus Nω‐nitro‐L‐arginine methyl ester hydrochloride (L‐NAME). Hepatic injury and function (aminotransferases, bile production, bromosulfophthalein clearance), and factors potentially involved in the susceptibility of steatotic livers to ischemia‐reperfusion injury, such as oxidative stress, mitochondrial damage, and vascular resistance, were studied. Nitric oxide (NO) production and constitutive and inducible NO synthase were also measured. Steatotic and nonsteatotic livers preserved in IGL‐1 solution showed lower transaminases, malondialdehyde, glutamate dehydrogenase levels, and higher bile production than UW‐solution‐preserved livers. IGL‐1 solution protected against oxidative stress, mitochondrial damage and the alterations in vascular resistance associated with cold ischemia‐reperfusion. Thus, at the end of reperfusion period, aspartate aminotransferase levels in steatotic livers were 281 ± 6 U/L in UW vs. 202 ± 10 U/L in IGL‐1 solution. Glutamate dehydrogenase was 463 ± 75 U/L in UW vs. 111 ± 4 U/L in IGL‐1 solution, and oxidative stress was 3.0 ± 0.1 nmol/mg prot in UW vs. 2.0 ± 0.1 nmol/mg prot in IGL‐1 solution. These beneficial effects of IGL‐1 solution were abolished by the addition of L‐NAME, which implicates NO in the benefits of IGL‐1. In conclusion, IGL‐1 solution provided steatotic livers with better protection against the deleterious effects of cold ischemia‐reperfusion injury than did UW solution. Liver Transpl 12:1215‐1223, 2006.

Addition of adenosine monophosphate‐activated protein kinase activators to University of Wisconsin solution: A way of protecting rat steatotic livers

This study investigates how the addition of trimetazidine (TMZ) and aminoimidazole‐4‐carboxamide ribonucleoside (AICAR) to University of Wisconsin (UW) solution protects steatotic livers. Steatotic and nonsteatotic livers were preserved for 24 hours at 4°C in UW and UW with TMZ and AICAR (separately or in combination) and then perfused ex vivo for 2 hours at 37°C. Adenosine monophosphate‐activated protein kinase (AMPK) or nitric oxide (NO) synthesis inhibition in livers preserved in UW with TMZ was also investigated. Hepatic injury and function (transaminases, bile production, and sulfobromophthalein clearance) and factors potentially involved in the susceptibility of steatotic livers to ischemia‐reperfusion (I/R), including vascular resistance, mitochondrial damage, adenosine triphosphate depletion, and oxidative stress were evaluated. AMPK, NO synthase (NOS), nitrate, and nitrite levels were also determined. The addition of TMZ and AICAR (separately or in combination) to UW reduced hepatic injury, improved functionality, and protected against the mechanisms responsible for the vulnerability of steatotic livers to I/R. Like AICAR, TMZ increased AMPK, constitutive NOS, and nitrates and nitrites, and conversely, AMPK or NO synthesis inhibition abolished the benefits of TMZ. In conclusion, TMZ, by means of AMPK, increased NO, thus protecting steatotic livers against their vulnerability to I/R injury. TMZ and AICAR may constitute new additives to UW solution in steatotic liver preservation, whereas a combination of both seems unnecessary. Liver Transpl 13:410–425, 2007.

Addition of carvedilol to University Wisconsin solution improves rat steatotic and nonsteatotic liver preservation

Here we examine the effect of adding carvedilol (CVD) to University of Wisconsin (UW) solution on the preservation of steatotic and nonsteatotic livers during cold ischemia and after normothermic reperfusion. We used an isolated perfused rat liver model. The following protocols were evaluated. Protocol 1 concerned the effect of CVD after cold ischemia. Steatotic and nonsteatotic livers were preserved for 24 hours in UW solution alone or with CVD. Livers without cold ischemia were used as controls. Transaminases were evaluated in the flushing effluent. Protocol 2 involved the effect of CVD after reperfusion. Both liver types were preserved for 24 hours in UW solution alone or with CVD and then perfused ex vivo for 2 hours at 37°C. Livers flushed and perfused without ischemia were used as controls. Hepatic injury and functionality [transaminases, bile production, and hepatic clearance of sulfobromophthalein (BSP)] were evaluated after reperfusion. In addition, factors potentially involved in hepatic ischemia‐reperfusion injury, including oxidative stress (malondialdehyde and superoxide anion levels), mitochondrial damage (glutamate dehydrogenase activity), microcirculatory disorders (flow rate and vascular resistance), and adenosine triphosphate (ATP) depletion, were evaluated after reperfusion. After cold ischemia, steatotic livers preserved in UW solution showed higher transaminase levels than nonsteatotic livers. After reperfusion, steatotic livers preserved in UW solution showed higher transaminase levels and lower bile production and BSP clearance than nonsteatotic livers. Alterations in the perfusion flow rate and vascular resistance, mitochondrial damage, and reduced ATP content were more evident in steatotic livers preserved in UW solution. The addition of CVD to UW solution reduced hepatic injury, obstructed its mechanisms, and improved hepatic functionality in both liver types. We conclude that CVD is a useful additive for UW solution that improves the preservation of steatotic and nonsteatotic livers subjected to prolonged cold ischemia. Liver Transpl 16:163–171, 2010.

New preservation strategies for preventing liver grafts against cold ischemia reperfusion injury

Background:  In spite of improvements in University of Wisconsin (UW) preservation solution, the injury from grafts during cold storage is an unresolved problem in liver transplantation. The aim of the present study was to evaluate the beneficial effect on ischemia–reperfusion injury associated with liver transplantation of the inversion of K+ and Na+ concentrations and the replacement of hydroxyethyl starch (HES) by polyethylene glycol (PEG) in UW preservation solution.

Improved rat steatotic and nonsteatotic liver preservation by the addition of epidermal growth factor and insulin-like growth factor-I to University of Wisconsin solution.

This study examined the effects of epidermal growth factor (EGF) and insulin‐like growth factor‐I (IGF‐I) supplementation to University of Wisconsin solution (UW) in steatotic and nonsteatotic livers during cold storage. Hepatic injury and function were evaluated in livers preserved for 24 hours at 4°C in UW and in UW with EGF and IGF‐I (separately or in combination) and then perfused ex vivo for 2 hours at 37°C. AKT was inhibited pharmacologically. In addition, hepatic injury and survival were evaluated in recipients who underwent transplantation with steatotic and nonsteatotic livers preserved for 6 hours in UW and UW with EGF and IGF‐I (separately or in combination). The results, based on isolated perfused liver, indicated that the addition of EGF and IGF‐I (separately or in combination) to UW reduced hepatic injury and improved function in both liver types. A combination of EGF and IGF‐I resulted in hepatic injury and function parameters in both liver types similar to those obtained by EGF and IGF‐I separately. EGF increased IGF‐I, and both additives up‐regulated AKT in both liver types. This was associated with glycogen synthase kinase‐3β (GSK3β) inhibition in nonsteatotic livers and PPARγ overexpression in steatotic livers. When AKT was inhibited, the effects of EGF and IGF‐I on GSK3β, PPARγ, hepatic injury and function disappeared. The benefits of EGF and IGF‐I as additives in UW solution were also clearly seen in the liver transplantation model, because the presence of EGF and IGF‐I (separately or in combination) in UW solution reduced hepatic injury and improved survival in recipients who underwent transplantation with steatotic and nonsteatotic liver grafts. In conclusion, EGF and IGF‐I may constitute new additives to UW solution in steatotic and nonsteatotic liver preservation, whereas a combination of both seems unnecessary. Liver Transpl 16:1098–1111, 2010.