Beneficial effect of pentoxifylline on microvesicular steatotic livers submitted to a prolonged cold ischemia

Modification of Preservative Fluids with Antioxidants in Terms of Their Efficacy in Liver Protection before Transplantation

Transplantation is currently the only effective treatment for patients with end-stage liver failure. In recent years, many advanced studies have been conducted to improve the efficiency of organ preservation techniques. Modifying the composition of the preservation fluids currently used may improve graft function and increase the likelihood of transplantation success. The modified fluid is expected to extend the period of safe liver storage in the peri-transplantation period and to increase the pool of organs for transplantation with livers from marginal donors. This paper provides a literature review of the effects of antioxidants on the efficacy of liver preservation fluids. Medline (PubMed), Scopus, and Cochrane Library databases were searched using a combination of MeSH terms: "liver preservation", "transplantation", "preservation solution", "antioxidant", "cold storage", "mechanical perfusion", "oxidative stress", "ischemia-reperfusion injury". Studies published up to December 2023 were included in the analysis, with a focus on publications from the last 30 years. A total of 45 studies met the inclusion criteria. The chemical compounds analyzed showed mostly bioprotective effects on hepatocytes, including but not limited to multifactorial antioxidant and free radical protective effects. It should be noted that most of the information cited is from reports of studies conducted in animal models, most of them in rodents.

To Protect Fatty Livers from Ischemia Reperfusion Injury: Role of Ischemic Postconditioning

BACKGROUND

The benefit of ischemic postconditioning (IPostC) might be the throttled inflow following cold ischemia. The current study investigated advantage and mechanisms of IPostC in healthy and fatty rat livers.

METHODS

Male SD rats received a high-fat diet to induce fatty livers. Isolated liver perfusion was performed after 24 h ischemia at 4 °C as well as in vivo experiments after 90 min warm ischemia. The so-called follow-up perfusions served to investigate the hypothesis that medium from IPostC experiments is less harmful. Lactate dehydrogenase (LDH), transaminases, different cytokines, and gene expressions, respectively, were measured.

RESULTS

Fatty livers showed histologically mild inflammation and moderate to severe fat storage. IPostC reduced LDH and TXB₂ in healthy and fatty livers and increased bile flow. LDH, TNF-α, and IL-6 levels in serum decreased after warm ischemia + IPostC. The gene expressions of Tnf, IL-6, Ccl2, and Ripk3 were downregulated in vivo after IPostC.

CONCLUSIONS

IPostC showed protective effects after ischemia in situ and in vivo in healthy and fatty livers. Restricted cyclic inflow was an important mechanism and further suggested involvement of necroptosis. IPostC represents a promising and easy intervention to improve outcomes after transplantation.

LXRalpha gene downregulation by lentiviral-based RNA interference enhances liver function after fatty liver transplantation in rats

BACKGROUND

Steatotic liver grafts, although accepted, increase the risk of poor posttransplantation liver function. However, the growing demand for adequate donor organs has led to the increased use of so-called marginal grafts. Liver X receptor alpha (LXRalpha) is important in fatty acid metabolism and interrelated with the specific ischemia-reperfusion injury in fatty liver transplantation. This study aimed to investigate whether LXRalpha RNA interference (RNAi) could improve the organ function of liver transplant recipients.

METHODS

Fifty Sprague-Dawley rats were fed with a high-fat diet and 56% alcohol. The livers of these animals had greater than 60% macrovesicular steatosis and were used as liver donors. The experimental donors were treated with 7X107 TU LXRalpha-RNAi-LV of a mixture injection and control donors with negative control-LV vector injection into the portal vein 72 hours before the operation. The effects of LXRalpha-RNAi-LV were assessed by serum aminotransferases, histology, immunostaining, and protein levels. The transcription of LXRalpha mRNA was assessed by reverse transcription-polymerase chain reaction.

RESULTS

Compared with controls, LXRalpha RNAi inhibited the expression of LXRalpha at the mRNA (0.53+/-0.03 vs 0.94+/-0.02, P<0.05) and protein levels (0.51+/-0.08 vs 1.09+/-0.12, P<0.05). LXRalpha RNAi also decreased the expressions of sterol regulatory element-binding protein 1c (SREBP-1c) and CD36. LXRalpha RNAi consequently reduced fatty acid accumulation in hepatocytes. Compared with control animals, LXRalpha RNAi-treated group had lower serum alanine aminotransferase, aspartate aminotransferase, interleukin-1beta, and tumor necrosis factor-alpha levels and milder pathologic damages. TUNEL analysis revealed a significant reduction of apoptosis in the livers of rats treated with LXRalpha-RNAi-LV, and overall survival as determined by the Kaplan-Meier method was improved among rats treated with LXRalpha-RNAi-LV (P<0.05).

CONCLUSION

LXRalpha-RNAi-LV treatment significantly downregulated LXRalpha expression and improve steatotic liver graft function and recipient survival after a fatty liver transplantation in rats.

Pentoxifylline enhances the protective effects of hypertonic saline solution on liver ischemia reperfusion injury through inhibition of oxidative stress

BACKGROUND

Liver ischemia reperfusion (IR) injury triggers a systemic inflammatory response and is the main cause of organ dysfunction and adverse postoperative outcomes after liver surgery. Pentoxifylline (PTX) and hypertonic saline solution (HTS) have been identified to have beneficial effects against IR injury. This study aimed to investigate if the addition of PTX to HTS is superior to HTS alone for the prevention of liver IR injury.

METHODS

Male Wistar rats were allocated into three groups. Control rats underwent 60 minutes of partial liver ischemia, HTS rats were treated with 0.4 mL/kg of intravenous 7.5% NaCl 15 minutes before reperfusion, and HPTX group were treated with 7.5% NaCl plus 25 mg/kg of PTX 15 minutes before reperfusion. Samples were collected after reperfusion for determination of ALT, AST, TNF-alpha, IL-6, IL-10, mitochondrial respiration, lipid peroxidation, pulmonary permeability and myeloperoxidase.

RESULTS

HPTX significantly decreased TNF-alpha 30 minutes after reperfusion. HPTX and HTS significantly decreased ALT, AST, IL-6, mitochondrial dysfunction and pulmonary myeloperoxidase 4 hours after reperfusion. Compared with HTS only, HPTX significantly decreased hepatic oxidative stress 4 hours after reperfusion and pulmonary permeability 4 and 12 hours after reperfusion.

CONCLUSION

This study showed that PTX added the beneficial effects of HTS on liver IR injury through decreases of hepatic oxidative stress and pulmonary permeability.

Pentoxifylline in liver ischemia and reperfusion

Pentoxifylline is a methylxanthine compound which was first filed in 1973 and registered in 1974 in the United States by Sanofi-Aventis Deustchland Gmbh for the treatment of intermittent claudication for chronic occlusive arterial disease. This methylxanthine was later discovered to be a phosphodiesterase inhibitor. Furthermore, its hemorheological properties and its function as an inhibitor of inflammatory cytokines, like TNF-α, allowed researchers to study its effects in organ ischemia and reperfusion and transplantation. Although this drug has demonstrated beneficial effects, the mechanisms by which Pentoxifylline exerts a protective effect are not fully understood. This paper focuses on reviewing the literature to define the effect of Pentoxifylline when used in liver ischemia and reperfusion injury. Our research shows different animal models in which Pentoxifylline has been used as well as different doses and time of administration, as the ideal dose and timing have not yet been ascertained in liver ischemia and reperfusion. In conclusion, Pentoxifylline has shown positive effects in liver ischemia and reperfusion injury, and the main mechanism seems to be associated with the inhibition of TNF-α.

The impact of hepatic steatosis on hepatic ischemia-reperfusion injury in experimental studies: a systematic review

Background. The impact of hepatic steatosis on outcome following hepatic ischemia-reperfusion injury (IRI) remains controversial with conflicting clinical results. A number of experimental studies have been published examining the relationship between hepatic steatosis and IRI. This systematic review evaluates these experimental studies. Methods. An electronic search of the Medline and Embase databases (January 1946 to June 2012) was performed to identify studies that reported relevant outcomes in animal models of hepatic steatosis subjected to IRI. Results. A total of 1314 articles were identified, of which 33 met the predefined criteria and were included in the study. There was large variation in the type of animal model, duration, and type of IRI and reporting of histological findings. Increased macrovesicular steatosis (>30%) was associated with increased histological damage, liver function derangement, and reduced survival. Increased duration of warm or cold ischemia had a negative impact on all outcomes measured. Microvesicular steatosis did not influence outcome. Conclusions. Findings from this systemic review support the hypothesis that livers with >30% macrovesicular steatosis are less tolerant of IRI. Clinically, it is likely that these findings are applicable to patients undergoing hepatic resection, but further studies are required to confirm these data.

Strategies to rescue steatotic livers before transplantation in clinical and experimental studies

The shortage of donor livers has led to an increased use of organs from expanded criteria donors. Included are livers with steatosis, a metabolic abnormality that increases the likelihood of graft complications post-transplantation. After a brief introduction on the etiology, pathophysiology, categories and experimental models of hepatic steatosis, we herein review the methods to rescue steatotic donor livers before transplantation applied in clinical and experimental studies. The methods span the spectrum of encouraging donor weight loss, employing drug therapy, heat shock preconditioning, ischemia preconditioning and selective anesthesia on donors, and the treatment on isolated grafts during preservation. These methods work at different stages of transplantation process, although share similar molecular mechanisms including lipid metabolism stimulation through enzymes or nuclear receptor e.g., peroxisomal proliferator-activated receptor, or anti-inflammation through suppressing cytokines e.g., tumor necrosis factor-α, or antioxidant therapies to alleviate oxidative stress. This similarity of molecular mechanisms implies possible future attempts to reinforce each approach by repeating the same treatment approach at several stages of procurement and preservation, as well as utilizing these alternative approaches in tandem.

Quantifying hepatic steatosis - more than meets the eye

AIMS

The non-alcoholic fatty liver disease (NAFLD) activity score (NAS) is the histological tool used to assess disease severity based on steatosis, inflammation and hepatocyte ballooning. As steatosis contributes up to three of a potential eight points to NAS, it is important to quantify steatosis accurately. We sought to determine the optimum histological technique for identifying fat in tissue.

METHODS AND RESULTS

Using tissue from a mouse model of NAFLD, with validation in human liver biopsies, the percentage steatosis and fat droplet size were assessed in haematoxylin and eosin (H&E)- and Oil Red-O (ORO)-stained sections by light microscopy and digital image analysis (DIA). Results were compared to biochemical tissue triglyceride content and MRI assessment of hepatic lipid content. H&E steatosis assessment correlated poorly with tissue triglyceride concentration. However, ORO DIA exhibited much higher sensitivity and specificity for steatosis and correlated very well with triglyceride concentration in mouse and human liver (R = 0.706, P = 0.001 and R = 0.894, P =0.041, respectively). MRI-based assessment of steatosis was inaccurate.

CONCLUSIONS

ORO DIA is the most accurate method for detecting and quantifying steatosis. Although H&E-based NAS remains clinically valid in both clinical research and experimental situations, ORO DIA is a more robust technique to assess liver steatosis accurately for NAS scoring.

Decreased apoptosis in fatty livers submitted to subnormothermic machine-perfusion respect to cold storage

Machine perfusion at subnormothermic temperature (20°C), MP20, was developed by Vairetti et al. and showed to afford a better preservation of fatty livers respect to traditional cold storage (CS) in terms of enzyme release into the perfusate and bile, glycogen stores, energy charge and oxidative stress. Here we investigated whether it also caused decreased cell death by apoptosis. Fatty and lean Zucker rats were submitted to MP20 or CS for 6 h and reperfused normothermically for 2 h. Apoptotic cells were revealed by immunohistochemistry of activated caspase-3 and M30 (new epitope on CK18 degraded by caspase-3) and by the TUNEL assay. Portal pressure was also determined. A statistically significant reduction of hepatocyte apoptosis, but especially of sinusoidal cells was determined for fatty livers submitted to MP20 respect to CS. Portal pressure was significantly lower after MP20 respect to CS. The reduction of sinusoidal cell death by apoptosis without need for anti-apoptotic therapies appears particularly positive since apoptotic sinusoidal cells hinder microcirculation in the sinusoids and are thrombogenic. These results further confirm the potential of MP20 for preserving fatty livers that would be otherwise discarded as grafts, and thus for increasing the donor pool for liver transplantation.

Multidrug donor preconditioning protects steatotic liver grafts against ischemia-reperfusion injury

BACKGROUND

Graft dysfunction of steatotic livers (SL) still remains a major challenge in liver transplantation. Different mechanisms are thought to be involved in the impaired tolerance of SL to ischemia-reperfusion injury. Thus, different pharmacologic strategies may need to be combined to effectively protect SL and to reduce graft dysfunction after transplantation. Therefore, we analyzed the effectiveness of a multidrug donor preconditioning (MDDP) procedure to protect SL from cold ischemia-reperfusion injury.

METHODS

Liver steatosis was induced by a high-carbohydrate, fat-free diet. A total of 24 Sprague-Dawley rats were divided into 3 groups (n = 8 each), including a control group with nonsteatotic livers (Con), a vehicle-treated SL group (SL-Con), and a SL group undergoing MDDP (SL-MDDP), including pentoxyphylline, glycine, deferoxamine, N-acetylcysteine, erythropoietin, melatonin, and simvastatin. MDDP was applied before liver perfusion with 4°C histidine-tryptophan-ketoglutarate (HTK) solution and organ harvest. After 24 hours of cold storage in HTK, postischemic reperfusion was performed in an isolated liver reperfusion model using 37°C Krebs-Henseleit bicarbonate buffer.

RESULTS

After 60 minutes of reperfusion, SL showed a significant reduction of bile flow as well as a marked increase of liver enzyme levels and apoptotic cell death compared with Con. This was associated with an increased malondialdehyde formation, interleukin-1 production, and leukocytic tissue infiltration. MDDP completely abolished the inflammatory response and was capable of significantly reducing parenchymal dysfunction and injury.

CONCLUSIONS

MDDP decreases SL injury after cold storage and reperfusion. The concept of MDDP as a simple and safe preoperative regime, thus may be of interest in clinical use, expanding the donor pool from marginal donors.

Fluorescence spectroscopy to diagnose hepatic steatosis in a rat model of fatty liver

BACKGROUND

Steatosis is diagnosed on the basis of the macroscopic aspect of the liver evaluated by the surgeon at the time of organ extraction or by means of a frozen biopsy.

AIM

In the present study, the applicability of laser-induced fluorescence (LIF) spectroscopy was investigated as a method for the diagnosis of different degrees of steatosis experimentally induced in rats.

MATERIAL AND METHODS

Rats received a high-lipid diet for different periods of time. The animals were divided into groups according to the degree of induced steatosis diagnosis by histology. The concentration of fat in the liver was correlated with LIF by means of the steatosis fluorescence factor (SFF).

RESULTS

The histology classification, according to liver fat concentration was, Severe Steatosis, Moderate Steatosis, Mild Steatosis and Control (no liver steatosis). Fluorescence intensity could be directly correlated with fat content. It was possible to estimate an average of fluorescence intensity variable by means of different confidence intervals (P=95%) for each steatosis group. SFF was significantly higher in the Severe Steatosis group (P<0.001) compared with the Moderate Steatosis, Mild Steatosis and Control groups.

CONCLUSION

The various degrees of steatosis could be directly correlated with SFF. LIF spectroscopy proved to be a method capable of identifying the degree of hepatic steatosis in this animal model, and has the potential of clinical application for non-invasive evaluation of the degree of steatosis.

Liver preservation: is there anything new yet?

PURPOSE OF REVIEW

To provide an update on recent developments in liver preservation through a comprehensive review of the literature.

RECENT FINDINGS

Comparisons of the available preservation solutions for liver transplantation based on recent trials suggest clinical equivalence. The debate continues regarding risk of biliary-tract complications. Development of new preservation solutions and agents that target specific mechanisms of steatotic and donors after cardiac death pathophysiology is showing promise in a variety of preclinical and clinical studies. Early clinical results of ischemic preconditioning are conflicting and so there is the need for additional clinical studies. The most important developments have been in the machine perfusion of the liver. New portable perfusion systems have shown promise in preclinical studies and may allow rapid evolution of clinical liver machine perfusion. The first human clinical trial is well underway with results showing safety and improved efficacy of preservation of transplanted human liver allografts.

SUMMARY

Liver preservation is in a period of rapid advance. In the future, a multifaceted liver-preservation strategy that integrates pharmacologic agents and hypothermic machine perfusion is likely to minimize organ injury and maximize patient outcomes. An ongoing challenge is to increase the number of innovations entering prospective and randomized clinical trials.

Current studies on therapeutic approaches for ischemia/reperfusion injury in steatotic livers

Steatotic livers are particularly vulnerable to ischemia/reperfusion (I/R) injury, resulting in poor outcomes following liver surgery and transplantation. Therapeutic approaches for I/R injury in steatotic livers are currently under intensive investigation. This review summarizes and discusses the approaches developed during the last few years to prevent hepatic I/R injury in steatotic livers. Among the proposed approaches, ischemic preconditioning and intermittent clamping are the two most promising approaches that have been applied in some clinical centers for liver surgery and transplantation, but most of others have not reached clinical application yet.

Effect of high fat diet on the volume of liver and quantitative feature of Kupffer cells in the female rat: a stereological and ultrastructural study

BACKGROUND

The role of Kupffer cells (KCs) in nonalcoholic steatohepatitis (NASH) which is regarded as a major cause of cryptogenic cirrhosis of the liver was investigated using stereological methods and electron microscopy in the rat model. To our knowledge, there is no stereological study on the volume of liver, total number, numerical density, and nuclear height of KCs of liver in the female rat fed with a high fat diet (HFD) in the literature.

METHOD

16 female Sprague Dawley rats were randomized into HFD and control group, with HFD and standard diet for 12 weeks, respectively. In this study, two basic research methods were used to analyze the samples. One was histopathological observation at both light and electron microscopic level. The other was stereological methods that consist of Cavalieri principle for liver volume estimation and physical disector method for estimation of numerical density and total number of KCs in the liver.

RESULTS

Liver volume, both mean numerical density and total number of KCs, were statistically increased in HFD rats. Ultrastructurally, a significant decrease in the mean nuclear height of KCs in HFD rats was also found. In the control group, no abnormal change was observed, but in the HFD group, some changes such as diffuse steatosis, mononuclear cell infiltration, necrosis, fibrosis, accumulation of fat droplets and intra-cytoplasmic vacuoles, and swollen mitochondria with irregular membranes were observed in the hepatocytes.

CONCLUSION

The number and activity of KCs are increased significantly in NASH induced by HFD, and KCs might be involved in the pathogenesis of steatohepatitis as previously attributed as a major cause of cryptogenic cirrhosis of the liver.

Subnormothermic machine perfusion protects against rat liver preservation injury: a comparative evaluation with conventional cold storage

Hypothermic machine perfusion (MP) of the liver has been reported to improve graft function reclaiming marginal livers, such as those from non-heart-beating donors. Livers from obese donors often have fatty infiltrates and are more susceptible to hypothermic conditions. No data exist about MP at temperatures >4 degrees C. This study evaluated liver function after organ preservation by comparing MP at 20 degrees C with conventional cold storage.

METHODS

For MP, rat livers were perfused for 6 hours using an oxygenated Krebs-Henseleit (KH) solution at 20 degrees C (pH 7.4). For cold storage, livers were perfused in situ and preserved with Celsior solution at 4 degrees C for 6 hours. The reperfusion period with KH (2 hours at 37 degrees C) was performed under the same conditions both among livers preserved by MP or cold storage. Hepatic enzyme release (aspartate aminotransferase [AST], alanine aminotransferase [ALT], lactate dehydrogenase [LDH], and gamma-glutamyl transferase [GGT]), bile production, and ATP levels were measured during MP and reperfusion.

RESULTS

At the end of reperfusion, livers preserved by MP showed significantly decreased liver damage compared with cold storage: AST, 18 +/- 4 vs. 45 +/- 6 mU/mL (P < .01); ALT, 1.5 +/- .07 vs. 6 +/- 0.5 mU/mL (P < .01); and LDH, 82 +/- 2 vs. 135 +/- 29 mU/mL (P < .05). No difference was observed between bile production between MP and cold storage. High levels of biliary GGT and LDH were found in cold preserved livers. ATP levels were higher in livers preserved with MP compared with those preserved by cold storage.

CONCLUSIONS

MP at 20 degrees C resulted in a better quality of liver preservation, improving hepatocyte survival, compared with conventional cold storage. This may provide a new method for successful utilization of marginal livers, in particular fatty livers.

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 degrees C in UW and UW with TMZ and AICAR (separately or in combination) and then perfused ex vivo for 2 hours at 37 degrees 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.

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 degrees C in University of Wisconsin (UW) or IGL-1 solution, respectively, and then perfused ex vivo for 2 hours at 37 degrees C. Additionally, Ob and Ln livers (n = 16, 8 Ln and 8 Ob) were preserved in IGL-1 plus Nomega-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.

Trimetazidine: Is it a promising drug for use in steatotic grafts?

AIM: Chronic organ-donor shortage has led to the acceptance of steatotic livers for transplantation, despite the higher risk of graft dysfunction or nonfunction associated with the ischemic preservation period of these organs. The present study evaluates the effects of trimetazidine (TMZ) on an isolated perfused liver model.

METHODS: Steatotic and non-steatotic livers were preserved for 24 h in the University of Wisconsin (UW) solution with or without TMZ. Hepatic injury and function (transaminases, bile production and sulfobromophthalein (BSP) clearance) and factors potentially involved in the susceptibility of steatotic livers to ischemia–reperfusion (I/R) injury, including oxidative stress, mitochondrial damage, microcirculatory diseases, and ATP depletion were evaluated.

RESULTS: Steatotic livers preserved in UW solution showed higher transaminase levels, lower bile production and BSP clearance compared with non-steatotic livers. Alterations in perfusion flow rate and vascular resistance, mitochondrial damage, and reduced ATP content were more evident in steatotic livers. TMZ addition to UW solution reduced hepatic injury and ameliorated hepatic functionality in both types of the liver and protected against the mechanisms potentially responsible for the poor tolerance of steatotic livers to I/R.

CONCLUSION: TMZ may constitute a useful approach in fatty liver surgery, limiting the inherent risk of steatotic liver failure following transplantation.

Micro- and macrovesicular steatotic liver model for transplantation induced by ethanol and protein-deficient diet

Steatotic liver grafts are associated with a high incidence of primary nonfunction and initial poor function. Due to the increasing number of liver transplant candidates, centers are inclined to accept marginal donors more frequently. For a lack of a reliable fatty liver model, preservation concepts for fatty livers have hardly been evaluated. Moreover, there is an ongoing debate on the relevance and impact of micro- versus macrovesicular steatotic organs. We therefore intended to establish a steatotic liver model in pigs comprising both micro- and macrovesicular steatotic livers. Five groups of pigs received daily 1 to 6 g ethanol/kg body weight and/or a protein-deficient diet for up to 72 days. Liver biopsy was carried out at days 24, 48, and 72. With an increasing amount and duration of ethanol intake, higher levels of microvesicular steatosis were induced. Ethanol and protein deficient diet resulted in more than 60% microvesicular steatosis after 72 days. Exclusively protein-deficient diet without ethanol induced macrovesicular steatosis of more than 70% after 72 days. For the first time, we established a porcine model of hepatic steatosis that comprises both histologic types of fatty liver: micro- and macrovesicular steatosis induced by ethanol and a protein-deficient diet. We would like to conclude that our model is particularly qualified to study new concepts of preservation for steatotic livers to improve on the posttransplant outcome.