Evaluation of rat liver apoptotic and necrotic cell death after cold storage using UW, HTK, and Celsior

Melatonin and its protective role in attenuating warm or cold hepatic ischaemia/reperfusion injury

Although the liver is the only organ with regenerative capacity, various injury factors induce irreversible liver dysfunction and end‐stage liver disease. Liver resection and liver transplantation (LT) are effective treatments for individuals with liver failure, liver cirrhosis and liver cancers. The remnant or transplanted liver tissues will undergo hepatic ischaemia/reperfusion (IR), which leads to oxidative stress, inflammation, immune injury and liver damage. Moreover, systemic ischaemia induced by trauma, stroke, myocardial ischaemia, haemorrhagic shock and other injury factors also induces liver ischaemia/reperfusion injury (IRI) in individuals. Hepatic IRI can be divided into warm IRI, which is induced by liver surgery and systemic ischaemia, and cold IRI, which is induced by LT. Multiple studies have shown that melatonin (MT) acts as an endogenous free radical scavenger with antioxidant capacity and is also able to attenuate hepatic IRI via its anti‐inflammatory and antiapoptotic capacities. In this review, we discuss the potential mechanisms and current strategies of MT administration in liver surgery for protecting against warm or cold hepatic IRI. We highlight strategies to improve the efficacy and safety of MT for attenuating hepatic IRI in different conditions. After the potential mechanisms underlying the interactions between MT and other important cellular processes during hepatic IR are clarified, more opportunities will be available to use MT to treat liver diseases in the future.

Structure and Function of Porcine Arteries Are Preserved for up to 6 Days Using the HypoRP Cold-storage Solution

BACKGROUND

Maintaining functional vessels during preservation of vascularized composite allografts (VCAs) remains a major challenge. The University of Wisconsin (UW) solution has demonstrated significant short-term benefits (4-6 h). Here we determined whether the new hypothermic resuscitation and preservation solution HypoRP improves both structure, survival, and function of pig arteries during storage for up to 6 days.

METHODS

Using porcine swine mesenteric arteries, the effects of up to 6-day incubation in a saline (PBS), UW, or HypoRP solution on the structure, cell viability, metabolism, and function were determined.

RESULTS

After incubation at 4°C, for up to 6 days, the structures of the arteries were significantly disrupted, especially the tunica media, following incubation in PBS, in contrast with incubation in the HypoRP solution and to a lesser extent, in UW solution. Those disruptions were associated with increased active caspase 3 indicative of apoptosis. Additionally, while incubation in PBS led to a significant decrease in the metabolic activity, UW and HypoRP solutions allowed a stable to increased metabolic activity following 6 days of cold storage. Functional responsiveness to phenylephrine (PE) and sodium nitroprusside (SNP) decreased over time for artery rings stored in PBS and UW solution but not for those stored in HypoRP solution. Moreover, artery rings cold-stored in HypoRP solution were more sensitive to ATP.

CONCLUSIONS

The HypoRP solution improved long-term cold storage of porcine arteries by limiting structural alterations, including the collagen matrix, reducing apoptosis, and maintaining artery contraction-relaxation functions for up to 6 days.

Pharmacological Benefits and Risk of Using Hormones in Organ Perfusion and Preservation Solutions in the Aspect of Minimizing Hepatic Ischemia-Reperfusion Injury during Storage

For several years, research has been carried out on the effectiveness of solutions for perfusion and preservation of organs, including the liver. There is a search for an optimal pharmacological composition of these solutions, allowing to preserve or improve vital functions of the organ for as long as possible until it is transplanted into a recipient. Hormones due to their properties, often resulting from their pleiotropic effects, may be a valuable component for optimizing the composition of liver perfusion and preservation solutions. The paper presents the current state of knowledge on liver perfusion and preservation solutions modified with hormones. It also shows the characteristics of the hormones evaluated, taking into account their physiological functions in the body.

Factors associated with immune hemolytic anemia after pediatric liver transplantation

Immune-mediated hemolytic anemia following SOT is a rare disorder, the risk factors for which are unknown. Our purpose was to analyze a seemingly increased incidence in our center with the aim to identify predisposing factors. This recipients single-center retrospective study reviewed the medical records of 96 pediatric LT between 2000 and 2013. IHA was defined as acute anemia with a positive direct antiglobulin test. Seven cases of immune-mediated hemolytic anemia were identified (incidence 8.5%). Three cases presented during the first 3 months following LT (early IHA), and 4 presented later (late IHA). All patients with late IHA required rituximab. Using univariate analysis, the following factors were associated with IHA onset: BA (P = .04), younger age (P = .04), and the use of IGL-1 preservation solution (P = .05). Late IHA was associated with viral infections occurring beyond 3 months following LT, younger age, and BA (P = .01). Overall, CMV infection was associated with the development of both early and late IHA: CMV-negative recipients who received an organ from a CMV-positive donor were more likely to develop IHA (P = .035), and de novo CMV infection during the first year post-LT was associated with late IHA (P = .03). IHA is a rare complication following pediatric LT, occurring more frequently in younger patients and patients with an initial diagnosis of BA. CMV-negative recipients and patients who experience a de novo CMV infection in the first year following LT seem particularly vulnerable. IGL-1 preservation solution may be associated with an increased likelihood of developing IHA, a novel finding which warrants further investigation.

Cryopreservation of Hepatocyte Microbeads for Clinical Transplantation

Intraperitoneal transplantation of hepatocyte microbeads is an attractive option for the management of acute liver failure. Encapsulation of hepatocytes in alginate microbeads supports their function and prevents immune attack of the cells. Establishment of banked cryopreserved hepatocyte microbeads is important for emergency use. The aim of this study was to develop an optimized protocol for cryopreservation of hepatocyte microbeads for clinical transplantation using modified freezing solutions. Four freezing solutions with potential for clinical application were investigated. Human and rat hepatocytes cryopreserved with University of Wisconsin (UW)/10% dimethyl sulfoxide (DMSO)/5% (300 mM) glucose and CryoStor CS10 showed better postthawing cell viability, attachment, and hepatocyte functions than with histidine-tryptophan-ketoglutarate/10% DMSO/5% glucose and Bambanker. The 2 freezing solutions that gave better results were studied with human and rat hepatocytes microbeads. Similar effects on cryopreserved microbead morphology (external and ultrastructural), viability, and hepatocyte-functions post thawing were observed over 7 d in culture. UW/DMSO/glucose, as a basal freezing medium, was used to investigate the additional effects of cytoprotectants: a pan-caspase inhibitor (benzyloxycarbonyl-Val-Ala-dl-Asp-fluoromethylketone [ZVAD]), an antioxidant (desferoxamine [DFO]), and a buffering and mechanical protectant (human serum albumin [HSA]) on RMBs. ZVAD (60 µM) had a beneficial effect on cell viability that was greater than with DFO (1 mM), HSA (2%), and basal freezing medium alone. Improvements in the ultrastructure of encapsulated hepatocytes and a lower degree of cell apoptosis were observed with all 3 cytoprotectants, with ZVAD tending to provide the greatest effect. Cytochrome P450 activity was significantly higher in the 3 cytoprotectant groups than with fresh microbeads. In conclusion, developing an optimized cryopreservation protocol by adding cytoprotectants such as ZVAD could improve the outcome of cryopreserved hepatocyte microbeads for future clinical use.

Improving the outcome of kidney transplantation by ameliorating renal ischemia reperfusion injury: lost in translation?

Kidney transplantation is the treatment of choice in patients with end stage renal disease. During kidney transplantation ischemia reperfusion injury (IRI) occurs, which is a risk factor for acute kidney injury, delayed graft function and acute and chronic rejection. Kidneys from living donors show a superior short- and long-term graft survival compared with deceased donors. However, the shortage of donor kidneys has resulted in expansion of the donor pool by using not only living- and brain death donors but also kidneys from donation after circulatory death and from extended criteria donors. These grafts are associated with an increased sensitivity to IRI and decreased graft outcome due to prolonged ischemia and donor comorbidity. Therefore, preventing or ameliorating IRI may improve graft survival. Animal experiments focus on understanding the mechanism behind IRI and try to find methods to minimize IRI either before, during or after ischemia. This review evaluates the different experimental strategies that have been investigated to prevent or ameliorate renal IRI. In addition, we review the current state of translation to the clinical setting. Experimental research has contributed to the development of strategies to prevent or ameliorate IRI, but promising results in animal studies have not yet been successfully translated to clinical use.

Preservation solutions used during abdominal transplantation: Current status and outcomes

Organ preservation remains an important contributing factor to graft and patient outcomes. During donor organ procurement and transportation, cellular injury is mitigated through the use of preservation solutions in conjunction with hypothermia. Various preservation solutions and protocols exist with widespread variability among transplant centers. In this review of abdominal organ preservation solutions, evolution of transplantation and graft preservation are discussed followed by classification of preservation solutions according to the composition of electrolytes, impermeants, buffers, antioxidants, and energy precursors. Lastly, pertinent clinical studies in the setting of hepatic, renal, pancreas, and intestinal transplantation are reviewed for patient and graft survival as well as financial considerations. In liver transplants there may be some benefit with the use of histidine-tryptophan-ketoglutarate (HTK) over University of Wisconsin solution in terms of biliary complications and potential cost savings. Renal grafts may experience increased initial graft dysfunction with the use of Euro-Collins thereby dissuading its use in support of HTK which can lead to substantial cost savings. University of Wisconsin solution and Celsior are favored in pancreas transplants given the concern for pancreatitis and graft thrombosis associated with HTK. No difference was observed with preservation solutions with respect to graft and patient survival in liver, renal, and pancreas transplants. Studies involving intestinal transplants are sparse but University of Wisconsin solution infused intraluminally in combination with an intra-vascular washout is a reasonable option until further evidence can be generated. Available literature can be used to ameliorate extensive variation across centers while potentially minimizing graft dysfunction and improving associated costs.

Oxygenated Static Preservation of Donation after Cardiac Death Liver Grafts Improves Hepatocyte Viability and Function

BACKGROUND

Cell therapy, such as hepatocyte transplantation (HTx), is promising for the treatment of metabolic liver diseases or as a bridge to orthotopic liver transplantation in patients with fulminant liver failure. However, one of the limitations of this therapy is the shortage of donors. The present study aims to investigate whether the two-layer method (TLM) of cold preservation with oxygenation improves the viability and activity of hepatocytes from rat donation after cardiac death (DCD) donors compared with results obtained with the University of Wisconsin (UW) solution. Moreover, we evaluated the hepatocyte function after culture or transplantation into the spleen.

MATERIALS AND METHODS

We used male Sprague-Dawley rats for this study. The DCD model was induced by phrenotomy after injecting heparin. We assigned rats based on warm ischemia times of 15 and 30 min to groups S and L, respectively. Each group (n = 5) was then subdivided as follows: (1) group S: not preserved (S/N), preserved by TLM for 3 h (S/TLM3) and 12 h (S/TLM12), and in the UW solution for 3 h (S/UW3) and 12 h (S/UW12), and (2) group L: not preserved (L/N), preserved by TLM for 3 h (L/TLM3) and 12 h (L/TLM12), and in the UW solution for 3 h (L/UW3) and 12 h (L/UW12). The cell viability and function of isolated DCD hepatocytes were analyzed for culture or HTx into the spleen.

RESULTS

The viability and ATP levels of DCD hepatocytes significantly improved after TLM compared with the values after preservation in cold UW solution in group S/N (p < 0.059). The levels of albumin production and urea synthesis by hepatocytes after culture were significantly higher in groups S/TLM3 and S/TLM12 than in groups S/UW3 and S/UW12 (p < 0.05), respectively. Further, serum albumin levels after HTx were also markedly higher in groups S/TLM3 and S/TLM12 than in groups S/UW3 and S/UW12. The morphological features revealed that cultured and transplanted hepatocytes remained clearly viable and maintained an expression for specific hepatic function, such as the production of albumin and glycogen.

CONCLUSION

This novel method of oxygenated cold preservation of DCD livers can expand the hepatocyte donor pool for HTx and establish a wider application of this developing technique.

Compared efficacy of preservation solutions in liver transplantation: a long-term graft outcome study from the European Liver Transplant Registry

Between 2003 and 2012, 42 869 first liver transplantations performed in Europe with the use of either University of Wisconsin solution (UW; N = 24 562), histidine-tryptophan-ketoglutarate(HTK; N = 8696), Celsior solution (CE; N = 7756) or Institute Georges Lopez preservation solution (IGL-1; N = 1855) preserved grafts. Alternative solutions to the UW were increasingly used during the last decade. Overall, 3-year graft survival was higher with UW, IGL-1 and CE (75%, 75% and 73%, respectively), compared to the HTK (69%) (p < 0.0001). The same trend was observed with a total ischemia time (TIT) >12 h or grafts used for patients with cancer (p < 0.0001). For partial grafts, 3-year graft survival was 89% for IGL-1, 67% for UW, 68% for CE and 64% for HTK (p = 0.009). Multivariate analysis identified HTK as an independent factor of graft loss, with recipient HIV (+), donor age ≥65 years, recipient HCV (+), main disease acute hepatic failure, use of a partial liver graft, recipient age ≥60 years, no identical ABO compatibility, recipient hepatitis B surface antigen (-), TIT ≥ 12 h, male recipient and main disease other than cirrhosis. HTK appears to be an independent risk factor of graft loss. Both UW and IGL-1, and CE to a lesser extent, provides similar results for full size grafts. For partial deceased donor liver grafts, IGL-1 tends to offer the best graft outcome.

A comparison of inflammatory, cytoprotective and injury gene expression profiles in kidneys from brain death and cardiac death donors

BACKGROUND

The superior long-term survival of kidneys from living donors (LDs) compared with kidneys from donation-after-brain-death (DBD) and donation-after-cardiac-death (DCD) donors is now well established. However, comparative studies on transcriptional changes that occur at organ retrieval and during and after cold ischemia (CI) are sparse.

METHODS

Using a rat model, we used qRT-PCR to examine expression levels of inflammatory, cytoprotective, and injury genes at different time points after organ retrieval. Cleaved caspase-3 was used to evaluate early apoptosis in DCD and DBD kidneys.

RESULTS

Immediately after retrieval, we found massive up-regulation of proinflammatory genes interleukin-1β, interleukin-6, tumor necrosis factor-α, monocyte chemotactic protein-1, P-selectin, and E-selectin in DBD compared with LD and DCD kidneys. A significant increase in the expression of injury markers Kim-1, p21, and the cytoprotective gene heme oxygenase-1 accompanied this. Bax was increased in DCD kidneys, and Bcl-2 was decreased in DBD kidneys. After 2 hr of CI in the LD group and 18 hr in the DBD and DCD groups, gene expression levels were similar to those found after retrieval. During 18 hr of cold storage, expression levels of these genes did not change. In DCD and DBD kidneys, early apoptosis increased after CI.

DISCUSSION/CONCLUSION

The gene expression profile in DBD kidneys represents an inflammatory and injury response to brain death. In contrast, DCD kidneys show only mild up-regulation of inflammatory and injury genes. These results may imply why delayed graft function in DCD kidneys does not have the deleterious effect it has on DBD kidneys.

Preservation solutions for static cold storage of abdominal allografts: which is best?

PURPOSE OF REVIEW

To update the reader on the recent literature in liver, kidney, pancreas, and intestine static cold preservation, and to identify which solutions are most advantageous for each organ.

RECENT FINDINGS

The comparison of randomized trials of histidine-tryptophan-ketoglutarate (HTK), Celsior, and University of Wisconsin solutions has shown equivalent risk of delayed graft function after kidney transplantation. Similar outcomes have been observed after pancreas preservation with University of Wisconsin, HTK, and Celsior solution. In live-donor liver transplantation, University of Wisconsin and HTK solution have shown equivalent results, whereas in the recent trials of deceased-donor liver transplantation, University of Wisconsin, HTK, and Celsior solutions have shown equivalence. Contrary to the most clinical trials, national registry data in kidney, pancreas, and liver transplantation demonstrate more detrimental effects and earlier graft loss after preservation with HTK versus University of Wisconsin solution. Early outcomes after intestinal transplantation with University of Wisconsin or HTK solution have shown no significant difference and animal studies indicate intraluminal preservation may be beneficial.

SUMMARY

The University of Wisconsin solution is the standard criterion static cold preservation for the procurement of liver, kidney, pancreas, and intestine. University of Wisconsin, HTK, and Celsior solutions all provide similar allograft outcomes in most clinical trials, but subtle differences have become more apparent in the recent studies and registry reports.

Comparison of energy metabolism in liver grafts from donors after circulatory death and donors after brain death during cold storage and reperfusion

Background

Donation after circulatory death (DCD) liver grafts have supplemented the donor organ pool, but certain adverse outcomes have prevented exploration of the full potential of such organs. The aim of this study was to determine key differences in basic energy metabolism between DCD and donation after brainstem death (DBD) grafts.

Methods

Microdialysis samples from DCD and DBD allograft parenchyma from cold storage to 48 h after reperfusion were analysed by colorimetric methods. Interstitial lactate, pyruvate and glycerol levels were measured and the lactate/pyruvate ratio was calculated to estimate energy depletion of the grafts. Histological features of ischaemia and reperfusion injury were assessed.

Results

Donor age, extent of steatosis and cold ischaemia time were comparable between ten DCD and 20 DBD organs. DCD grafts had higher levels of interstitial lactate (median 11·6 versus 1·2 mmol/l; P = 0·015) and increased lactate/pyruvate ratio (792 versus 38; P = 0·001) during cold storage. There was no significant difference in glycerol levels between DCD and DBD grafts (225·1 versus 127·5 µmol/l respectively; P = 0·700). Rapid restoration of energy levels with lactate clearance, increased pyruvate levels and reduced lactate/pyruvate ratio was seen following reperfusion of functioning DCD grafts, parallel with levels in DBD grafts. Histology revealed more pronounced glycogen depletion in DCD grafts. Three allografts that failed owing to primary non-function showed energy exhaustion with severe glycogen depletion.

Conclusion

Liver grafts from DCD donors exhibited depletion of intracellular energy reserves during cold storage. Failed allografts showed severe energy depletion. Modified organ preservation techniques to minimize organ injury related to altered energy metabolism may enable better utilization of donor organs after circulatory death.

Impact of a new refrigerator on the preservation of hepatic grafts

AIM

  Current medical transplantation methods focus on solutions for major problems such as the shortage of donors. To overcome these issues, expanding organ preservation time has become a major concern. A new refrigerating chamber has been recently developed, which can cool the inside of a material to the required temperature by frequently sensing the temperature of both inside and surface of the materials. The purpose of this study is to evaluate the usefulness of a new refrigerating system in hepatic preservation.

METHODS

  The liver grafts were harvested from rats and divided into two groups. Group A consisted of grafts preserved in chilled University of Wisconsin solution (UW) solution (on ice) for 24, 72 and 168 h. Group B consisted of grafts preserved in the UW solution in a new refrigerator at 4°C.

RESULTS

  In group B, aspartate aminotransferase released into effluent after cold storage for 72 h showed a marked decrease compared to group A (P < 0.05). The levels of ammonia and lactate decreased significantly in group B (P < 0.05). In group B, the levels of adenosine triphosphate were significantly preserved after cold storage for 24 h and 72 h compared to group A (P < 0.05). Immunohistochemistry showed positive cells for heme oxygenase-1 were significantly increased in group B after cold storage.

CONCLUSION

  This new refrigerator can improve preservation injury of hepatic grafts and may provide an innovative technique for liver transplantation.

Ischemia-Reperfusion Injury and Ischemic-Type Biliary Lesions following Liver Transplantation

Ischemia-reperfusion (I-R) injury after liver transplantation (LT) induces intra- and/or extrahepatic nonanastomotic ischemic-type biliary lesions (ITBLs). Subsequent bile duct stricture is a significant cause of morbidity and even mortality in patients who underwent LT. Although the pathogenesis of ITBLs is multifactorial, there are three main interconnected mechanisms responsible for their formation: cold and warm I-R injury, injury induced by cytotoxic bile salts, and immunological-mediated injury. Cold and warm ischemic insult can induce direct injury to the cholangiocytes and/or damage to the arterioles of the peribiliary vascular plexus, which in turn leads to apoptosis and necrosis of the cholangiocytes. Liver grafts from suboptimal or extended-criteria donors are more susceptible to cold and warm I-R injury and develop more easily ITBLs than normal livers. This paper, focusing on liver I-R injury, reviews the risk factors and mechanisms leading to ITBLs following LT.

Effects of ischemic preconditioning associated to different preservation solutions in protecting the intestinal graft

PURPOSE

To evaluate the effects of ischemic preconditioning (IPC) associate with different preservation solutions, in the protecting of gut.

METHODS

Four groups of 14 rats underwent laparotomy and collecting 20 cm of ileum, for preservation, at 4ºC, in Belzer (Belz), Ringer (RL), Celsior (Cs) and Custodiol (Cust) solutions, for 24 hours. Prior to collection, half of the animals in each group were subjected to IPC. During preservation, in the periods of zero, 12, 18 and 24 hours, were conducted evaluating the degree of mucosal injury and dosage of malondialdehyde acid (MDA).

RESULTS

In all periods the RL group, with and without IPC, presented MDA values higher than the Belz and Cs. The degree of mucosal injury in the non-ipc RLgroup with 12h preservation was higher than the others; with 18 and 24h, the RL and Cust had higher degrees of damage than Cs and Belz. With IPC, in all periods, the group Cs and Belz had lower degrees of injury.

CONCLUSION

The Celsior and Belzer solutions had better protective effects on the gut and these effects were enhanced by IPC.

The use of a prostacyclin analog, iloprost, as an adjunct to uterus preservation with histidine-tryptophan-ketoglutarate solution

INTRODUCTION

Although assisted reproductive techniques have made most causes of both male and female infertility treatable, uterine factor infertility is not able to therapy. Therefore, transplantation of the uterus has been suggested as a future possible cure. Organ preservation solutions seek to reduce reperfusion injury. Since iloprost is an antioxidant with cytoprotective properties, we investigated its potential positive effects in histidine-tryptophan-ketoglutarate (HTK) solution after 4 or 24 h cold storage period of the rat uterus.

METHODS

We divided 24 female Wistar-albino rats into four groups: Group 1 had the uterus tissue stored in HTK solution at 4 °C for 4h. Group 2, the tissue was stored in HTK solution combined with iloprost (10(-8) M) for 4h at 4 °C. The same procedures were repeated for 24 h for Groups 3 and 4 respectively. Tissue levels of malondialdehyde (MDA) and nitric oxide (NO), as indicators of oxidative stress were determined with histopathological evaluations.

RESULTS

MDA and NO levels were compared between the group 1 vs 3; and 2 vs 4. No significant difference was observed between the groups. Cold storage for 24 h produced alterations in histological appearances that were mitigated by the addition of iloprost to HTK solution.

CONCLUSION

In conclusion, addition of iloprost to HTK solution reversed the histological alterations after 24h-cold storage of the rat uterus.

Improvement of the cold storage of isolated human hepatocytes

Increasing amounts of human hepatocytes are needed for clinical applications and different fields of research, such as cell transplantation, bioartificial liver support, and pharmacological testing. This demand calls for adequate storage options for isolated human liver cells. As cryopreservation results in severe cryoinjury, short-term storage is currently performed at 2-8°C in preservation solutions developed for the storage of solid organs. However, besides slowing down cell metabolism, cold also induces cell injury, which is, in many cell types, iron dependent and not counteracted by current storage solutions. In this study, we aimed to characterize storage injury to human hepatocytes and develop a customized solution for cold storage of these cells. Human hepatocytes were isolated from material obtained from partial liver resections, seeded in monolayer cultures, and, after a preculture period, stored in the cold in classical and new solutions followed by rewarming in cell culture medium. Human hepatocytes displayed cold-induced injury, resulting in >80% cell death (LDH release) after 1 week of cold storage in University of Wisconsin solution or cell culture medium and 3 h of rewarming. Cold-induced injury could be significantly reduced by the addition of the iron chelators deferoxamine and LK 614. Experiments with modified solutions based on the new organ preservation solution Custodiol-N showed that ion-rich variants were better than ion-poor variants, chloride-rich solutions better than chloride-poor solutions, potassium as main cation superior to sodium, and pH 7.0 superior to pH 7.4. LDH release after 2 weeks of cold storage in the thus optimized solution was below 20%, greatly improving cold storage of human hepatocytes. The results were confirmed by the assessment of hepatocellular mitochondrial membrane potential and functional parameters (resazurin reduction, glucagon-stimulated glucose liberation) and thus suggest the use of a customized hepatocyte storage solution for the cold storage of these cells.

Liver transplantation using University of Wisconsin or Celsior preserving solutions in the portal vein and Euro-Collins in the aorta

INTRODUCTION

Orthotopic liver transplantation (OLT) is today the gold standard treatment of the end-stage liver disease. Different solutions are used for graft preservation. Our objective was to compare the results of cadaveric donor OLT, preserved with the University of Wisconsin (UW) or Celsior solutions in the portal vein and Euro-Collins in the aorta.

METHODS

We evaluated retrospectively 72 OLT recipients, including 36 with UW solution (group UW) and 36 with Celsior (group CS). Donors were perfused in situ with 1000 mL UW or Celsior in the portal vein of and 3000 mL of Euro-Collins in the aortia and on the back table managed with 500 mL UW or Celsior in the portal vein, 250 mL in the hepatic artery, and 250 mL in the biliary duct. We evaluated the following variables: donor characteristics, recipient features, intraoperative details, reperfusion injury, and steatosis via a biopsy after reperfusion. We noted grafts with primary nonfunction (PNF), initial poor function (IPF), rejection episodes, biliary duct complications, hepatic artery complications, re-OLT, and recipient death in the first year after OLT.

RESULTS

The average age was 33.6 years in the UW group versus 41 years in the CS group (P = .048). There was a longer duration of surgery in the UW group (P = .001). The other recipient characteristics, ischemia-reperfusion injury, steatosis, PNF, IPF, rejection, re-OLT, and recipient survival were not different. Stenosis of the biliary duct occured in 3 (8.3%) cases in the UW group and 8 (22.2%) in the CS (P = .19) with hepatic artery thrombosis in 4 (11.1%) CS versus none in the UW group (P = .11).

CONCLUSION

Cadaveric donor OLT showed similar results with organs preserved with UW or Celsior in the portal vein and Euro-Collins in the aorta.

Hypoxia inducible factor-1α accumulation in steatotic liver preservation: Role of nitric oxide

AIM: To examine the relevance of hypoxia inducible factor (HIF-1) and nitric oxide (NO) on the preservation of fatty liver against cold ischemia-reperfusion injury (IRI).

METHODS: We used an isolated perfused rat liver model and we evaluated HIF-1α in steatotic and non-steatotic livers preserved for 24 h at 4°C in University of Wisconsin and IGL-1 solutions, and then subjected to 2 h of normothermic reperfusion. After normoxic reperfusion, liver enzymes, bile production, bromosulfophthalein clearance, as well as HIF-1α and NO [endothelial NO synthase (eNOS) activity and nitrites/nitrates] were also measured. Other factors associated with the higher susceptibility of steatotic livers to IRI, such as mitochondrial damage and vascular resistance were evaluated.

RESULTS: A significant increase in HIF-1α was found in steatotic and non-steatotic livers preserved in IGL-1 after cold storage. Livers preserved in IGL-1 showed a significant attenuation of liver injury and improvement in liver function parameters. These benefits were enhanced by the addition of trimetazidine (an anti-ischemic drug), which induces NO and eNOS activation, to IGL-1 solution. In normoxic reperfusion, the presence of NO favors HIF-1α accumulation, promoting also the activation of other cytoprotective genes, such as heme-oxygenase-1.

CONCLUSION: We found evidence for the role of the HIF-1α/NO system in fatty liver preservation, especially when IGL-1 solution is used.

Pharmacological strategies against cold ischemia reperfusion injury

IMPORTANCE OF THE FIELD

Good organ preservation is a determinant of graft outcome after revascularization. The necessity of increasing the quality of organ preservation, as well as of extending cold storage time, has made it necessary to consider the use of pharmacological additives.

AREAS COVERED IN THIS REVIEW

The complex physiopathology of cold-ischemia-reperfusion (I/R) injury--and in particular cell death, mitochondrial injury and endoplasmic reticulum stress--are reviewed. Basic principles of the formulation of the different preservation solutions are discussed.

WHAT THE READER WILL GAIN

Current strategies and new trends in static organ preservation using additives such as trimetazidine, polyethylene glycols, melatonin, trophic factors and endothelin antagonists in solution are presented and discussed. The benefits and mechanisms responsible for enhancing organ protection against I/R injury are also discussed. Graft preservation was substantially improved when additives were added to the preservation solutions.

TAKE HOME MESSAGE

Enrichment of preservation solutions by additives is clinically useful only for short periods. For longer periods of cold ischemia, the use of such additives becomes insufficient because graft function deteriorates as a result of ischemia. In such conditions, the preservation strategy should be changed by the use of machine perfusion in normothermic conditions.

Comparative prospective study of two liver graft preservation solutions: University of Wisconsin and Celsior

University of Wisconsin solution (UWS) is the gold standard for graft preservation. Celsior solution (CS) is a new solution not as yet widely used in liver grafts. The aim of this study was to compare the liver function of transplanted grafts stored in these 2 preservation solutions. The primary endpoints were the rates of primary nonfunction (PNF) and primary dysfunction (PDF). We performed a prospective and pseudorandomized study that included 196 patients (representing 104 and 92 livers preserved in UWS and CS, respectively) at La Fe University Hospital (Valencia, Spain) between March 2003 and May 2005. PNF and PDF rates, liver function laboratory parameters, postoperative bleeding, vascular and biliary complications, and patient and graft survival at 3 years were compared for the 2 groups. The 2 groups were similar in terms of donor variables, recipient variables, and surgical techniques. The PNF rates were 2.2% and 1.9% in the CS and UWS groups, respectively (P = not significant), and the PDF rates were 15.2% and 15.5% in the CS and UWS groups, respectively (P = not significant). There were no significant differences in the laboratory parameters for the 2 groups, except for alanine aminotransferase levels in month 3, which were lower in the CS group (P = 0.01). No significant differences were observed in terms of complications. Three-year patient and graft survival rates were as follows for years 1, 2, and 3: 83%, 80%, and 76% (patient) and 80%, 77%, and 73% (graft) for the UWS group and 83%, 77%, and 70% (patient) and 81%, 73%, and 67% (graft) for the CS group (P = not significant). In conclusion, this study shows that CS is as effective as UWS in liver preservation.

Histidine-tryptophan-ketoglutarate (HTK) is associated with reduced graft survival of deceased donor kidney transplants

Single-center studies have reported equivalent outcomes of kidney allografts recovered with histidine-tryptophan-ketoglutarate (HTK) or University of Wisconsin (UW) solution. However, these studies were likely underpowered and often unadjusted, and multicenter studies have suggested HTK preservation might increase delayed graft function (DGF) and reduce graft survival of renal allografts. To further inform clinical practice, we analyzed the United Network for Organ Sharing (UNOS) database of deceased donor kidney transplants performed from July 2004 to February 2008 to determine if HTK (n = 5728) versus UW (n = 15 898) preservation impacted DGF or death-censored graft survival. On adjusted analyses, HTK preservation had no effect on DGF (odds ratio [OR] 0.99, p = 0.7) but was associated with an increased risk of death-censored graft loss (hazard ratio [HR] 1.20, p = 0.008). The detrimental effect of HTK was a relatively late one, with a strong association between HTK and subsequent graft loss in those surviving beyond 12 months (HR 1.43, p = 0.007). Interestingly, a much stronger effect was seen in African-American recipients (HR 1.55, p = 0.024) than in Caucasian recipients (HR 1.18, p = 0.5). Given recent studies that also demonstrate that HTK preservation reduces liver and pancreas allograft survival, we suggest that the use of HTK for abdominal organ recovery should be reconsidered.

Increased primary non-function in transplanted deceased-donor kidneys flushed with histidine-tryptophan-ketoglutarate solution

Histidine-Tryptophan-Ketoglutarate (HTK) solution is increasingly used to flush and preserve organ donor kidneys, with efficacy claimed equivalent to University of Wisconsin (UW) solution. We observed and reported increased graft pancreatitis in pancreata flushed with HTK solution, which prompted this review of transplanting HTK-flushed kidneys. We analyzed outcomes of deceased-donor kidneys flushed with HTK and UW solutions with a minimum of 12 months follow-up, excluding pediatric and multi-organ recipients. We evaluated patient and graft survival and rejection rates, variables that might constitute hazards to graft survival and renal function. Two-year patient survival, rejection, renal function and graft survival were not different, but early graft loss (<6 months) was worse in HTK-flushed kidneys (p < 0.03). A Cox analysis of donor grade, cold ischemic time, panel reactive antibodies (PRA), donor race, first vs. repeat transplant, rejection and flush solution showed that only HTK use predicted early graft loss (p < 0.04; relative risk = 3.24), almost exclusively attributable to primary non-function (HTK, n = 5 (6.30%); UW, n = 1 (0.65%); p = 0.02). Delayed graft function and early graft loss with HTK occurred only in lesser grade kidneys, suggesting it should be used with caution in marginal donors.

Hypothermic storage of isolated human hepatocytes: a comparison between University of Wisconsin solution and a hypothermosol platform

Until now little is known about the functional integrity of human hepatocytes after hypothermic storage. In order to address this limitation, we evaluated several commercially available hypothermic preservation media for their abilities to protect freshly isolated hepatocytes during prolonged cold storage. Human hepatocytes were isolated from non-transplantable/rejected donor livers and resuspended in ice-cold University of Wisconsin solution (UW), HypoThermosol-Base (HTS-Base), or HypoThermosol-FRS (HTS-FRS) with or without the addition of fetal bovine serum. Cells were stored at 4 degrees C for 24-72 h, and evaluated for hepatocyte viability (trypan blue exclusion, or labeling with fluorochromes), cell attachment, and function. The energy status of hepatocytes was evaluated by measurement of intracellular adenosine 5'-triphosphate. To determine whether the test cells expressed metabolic functions of freshly isolated cells, the activities of major phase I (cytochromes P450, FMO) and phase II (UGT, ST) drug-metabolizing enzymes were examined. Although hepatocytes are shown to be satisfactory after 24 h storage in all of the tested solutions, the cell viability, energy status, and xenobiotic metabolism following cold preservation in HTS-FRS was consistently and, in some cases, markedly higher when compared with other systems. The same metabolites for each of the tested substrates were detected in all groups of cells. Moreover, the use of HTS-FRS eliminates the need for serum in preservation solutions. HTS-FRS represents an improved solution compared to HTS-Base and UW for extending the shipping/storage time of human hepatocytes.

Quality control for clinical islet transplantation: organ procurement and preservation, the islet processing facility, isolation, and potency tests

Pancreatic islet transplantation has become one of the ideal treatments for patients with type 1 diabetes mellitus due to improvements in isolation techniques and immunosuppression regimens. In order to ensure the safety and rights of patients, isolated islets need to meet the criteria for regulation as both a biological product and a drug product. For the constant success of transplantation, therefore, all investigators involved in clinical islet transplantation must strive to ensure the safety, purity, and potency of islets in all the phases of clinical islet isolation and transplantation. In this review, we summarize the quality control for clinical islet isolation and transplantation, and the latest topics of pre-transplant islet assessment.

Histidine-Tryptophan-Ketoglutarate (HTK) is associated with reduced graft survival in deceased donor livers, especially those donated after cardiac death

Single-center studies have reported that liver allograft survival is not affected by preservation in histidine-tryptophan-ketoglutarate (HTK) versus University of Wisconsin (UW) solution. We analyzed the UNOS database of liver transplants performed from July, 2004, through February, 2008, to determine if preservation with HTK (n = 4755) versus UW (n = 12 673) impacted graft survival. HTK preservation of allografts increased from 16.8% in 2004 to 26.9% in 2008; this was particularly striking among donor after cardiac death (DCD) allografts, rising from 20.7% in 2004 to 40.9% in 2008. After adjusting for donor, recipient and graft factors that affect graft survival, HTK preservation was associated with an increased risk of graft loss (HR 1.14, p = 0.002), especially with DCD allografts (HR 1.44, P = 0.025) and those with cold ischemia time over 8 h (HR 1.16, P = 0.009). Furthermore, HTK preservation was associated with a 1.2-fold higher odds of early (< 30 days) graft loss as compared to UW preservation (OR 1.20, p = 0.012), with a more pronounced effect on allografts with cold ischemia time over 8 h (OR 1.31, p = 0.007), DCD allografts (OR 1.63, p = 0.09) and donors over 70 years (OR 1.67, p = 0.081). These results suggest that the increasing use of HTK for abdominal organ preservation should be reexamined.

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.

Improved microcirculation by low-viscosity histidine- tryptophan-ketoglutarate graft flush and subsequent cold storage in University of Wisconsin solution: results of an orthotopic rat liver transplantation model

As previously shown in a model of isolated rat liver perfusion, the combined use of an initial graft flush with low-viscosity histidine-tryptophan-ketoglutarate (HTK) solution followed by cold storage in University of Wisconsin (UW) solution markedly improved the preservation during an extended cold storage period. In this study, we aimed to transfer our results into an in vivo model of orthotopic rat liver transplantation, and to elucidate the potential mechanism of the improved preservation by focusing on the hepatic microcirculation. Livers were harvested from male Wistar rats. Aortic perfusion with a pressure of 100 cm H(2)O was performed with either UW (group UW) or HTK (groups UW and HTK_UW), followed by additional back-table perfusion with UW (group HTK_UW). After 20-h cold storage at 4 degrees C, livers were orthotopically transplanted with reconstructing the hepatic artery. As measured by bile flow and liver enzymes, HTK flush followed by UW storage was superior compared to single use of either UW or HTK solution. The hepatic microcirculation was significantly improved, as shown by the increased percentage of reperfused sinusoids and reduced sinusoidal leucostasis. HTK and UW effectively reduce ischaemia-reperfusion injury after liver transplantation. By combining the comparative advantages of both solutions, a cumulative effect resulting in an improved preservation was shown. Thus, this mechanism improves microcirculatory reperfusion.

Cold preservation of the liver with oxygenation by a two-layer method

BACKGROUND

The two-layer method (TLM) has recently been found to be superior to simple cold storage in University of Wisconsin (UW) solution as a means of pancreas preservation for islet transplantation. In this study, we investigated whether TLM would result in better hepatocyte function over UW cold storage and if it could be applied to hepatocyte transplantation.

MATERIALS AND METHODS

Hepatocytes from male Sprague Dawley rat livers were isolated and divided into three groups: a non-preservation group (group 1), a 10-h preservation group (group 2), and a 24-h preservation group (group 3). Groups 2 and 3 were then divided into three subgroups: a group preserved by the TLM (subgroup a), a group preserved in UW solution (subgroup b), and a group preserved in water (subgroup c). Isolated hepatocytes were evaluated for cell yield, viability, and adenosine triphosphate level after preservation. Hepatocytes were either cultured or transplanted.

RESULTS

Although no differences in cell yield or morphological findings were observed between any of the groups, TLM significantly improved hepatocyte viability and adenosine triphosphate levels in comparison with UW cold storage. Albumin production or urea synthesis were significantly higher in subgroup 3a than in subgroup 3b at almost all time points. Surprisingly, after hepatocyte transplantation, the serum albumin level in subgroup 2a was significantly higher than in subgroup 2b at every time point.

CONCLUSIONS

The results of this study demonstrated that liver preservation by the TLM before hepatocyte isolation might be beneficial and will be useful in the field of hepatotocyte transplantation.

Heat preconditioning ameliorates hepatocyte viability after cold preservation and rewarming, and modulates its immunoactivity

BACKGROUND

Heat preconditioning significantly preserved liver graft function after cold preservation in animal experimental model. The elevation of heat shock protein 70 (HSP70) was claimed to play a critical role in protecting grafts against cold preservation-induced hepatocyte apoptosis. However, little is known about whether HSP70 also plays an immunomodulatory role in cold preserved cells. This study aimed at investigating the relationship between HSP70 protein and the immunoactivity in response to lipopolysaccharide (LPS) stimulation.

METHODS AND RESULTS

A normal rat hepatocyte cell line was preserved with University of Wisconsin (UW) solution, Ringer's lactate solution (RL), and phosphate-buffered saline (PBS) at 4 degrees C. No significant morphological alteration was noted in UW-preserved cells after 24 h through phase-contrast microscopic observation and fluorescent viability stain. Western blotting showed a two-fold increase in the ratio of HSP70/Bax proteins in cells after 24 h of UW preservation. Heat preconditioning significantly enhanced the recovery of lactate dehydrogenase (LDH) activity in both RL- and UW-preserved cells that were stored for a period of 12 h or less. Moreover, heat preconditioning promoted HSP70 and NF-kappaB p50 nuclear translocation and suppressed the LPS-induced nuclear p50 accumulation in cells before UW preservation. Immunofluorescent stain revealed that the LPS-induced p50 protein redistribution to nuclear membrane might contribute to NF-kappaB activation, while heat preconditioning and UW cold preservation completely abrogated the p50 intranuclear redistribution. Thus NF-kappaB p50 might be responsible for the endotoxin tolerance induction.

CONCLUSIONS

These findings strongly suggest that heat preconditioning not only preserves hepatocyte viability after cold preservation and rewarming, but also ameliorates its immunoactivity.

Histidine-tryptophan-ketoglutarate solution vs. University of Wisconsin solution for liver transplantation: a systematic review

University of Wisconsin (UW) solution has been recognized as the gold standard in liver preservation, but its limitations are becoming obvious, such as risk of biliary complications and its high cost. Alternatively, the effects of histidine-tryptophan-ketoglutarate (HTK), such as improved biliary protection and low cost, have been observed. This systematic review is conducted to compare the efficacy and safety of these 2 solutions. Databases from 1966 to June 2006 were searched. Randomized clinical trials (RCTs) and cohort studies comparing HTK and UW solutions for liver transplantation were included. Ten articles including 11 comparisons (1,200 patients) met the inclusion criteria, containing 2 RCTs and 9 cohort studies. No marked differences existed between the 2 groups in patient and graft survival rates, acute rejection, primary nonfunction, primary dysfunction, delayed graft function, and ALT and AST levels after transplantation. The only positive result was observed in the bile production after deceased donor liver transplantation (DDLT), which was statistically significantly higher in HTK group than that of UW group (95% confidence interval, 18.65-57.47; P=0.0001). Although the difference in biliary complications between the 2 groups did not reach statistical significance, HTK was thought to be more effective for biliary tract flush and prevention of biliary complications in some studies. There was no statistically significant difference of effects (except bile production) between HTK and UW. But trends were documented in some studies for the superiority of HTK in biliary tract flush, prevention of biliary complications, and cost saving. Adequately powered RCTs with longer follow-up periods are required to evaluate the long-term effect of these 2 solutions.

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.

METHODS

Using an orthotopic liver transplantation model, the effects on rat liver preservation of a modified preservation solution (UW-PEG) were evaluated, based on the inversion of K(+) and Na(+) concentration and the replacement of HES by PEG 35 kDa (0.03 mmol/L) in UW preservation solution.

RESULTS

The use of UW-PEG preservation solution ameliorated the biochemical and histological parameters of hepatic damage. Thus, at 24 h after transplantation, transaminase levels were reduced significantly when livers were preserved during 8 h in UW-PEG preservation solution compared with the original UW solution. In addition, histological findings revealed fewer and smaller areas of hepatocyte necrosis. The benefits of UW-PEG solution cannot be explained by modifications in oxidative stress or neutrophil accumulation associated with liver transplantation. However, the results of hepatic and portal blood flow indicated that the benefits of this modified preservation solution, UW-PEG were associated with improvements in the microcirculatory disorders after reperfusion.

CONCLUSIONS

The UW-PEG solution, while retaining all the advantages of UW solution, improved hepatic ischemia-reperfusion injury associated with liver transplantation.

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.

Low viscosity histidine-tryptophan-ketoglutarate graft flush improves subsequent extended cold storage in University of Wisconsin solution in an extracorporeal rat liver perfusion and rat liver transplantation model

Adequate flushing for liver donation requires large fluid volumes delivered at a high flow. This can be achieved more effectively with crystalloid solutions than with colloid-based solutions. This study examined the combination of initial histidine-tryptophan-ketoglutarate solution (HTK) graft flush and subsequent storage in University of Wisconsin solution (UW) to that of the single use of each solution. Livers from inbred Wistar rats were procured using aortic perfusion with UW or HTK for initial perfusion and reflushed after 30 minutes using either solution. In a third group, after perfusion with HTK, organs were reflushed with UW. A 60-minute in-vitro recirculating perfusion was performed after 24 hours of cold storage in the subsequent solution, as well as allotransplantation after 18 and 24 hours of cold storage. In extracorporeal perfusion, the HTK flush followed by UW storage was superior compared to the single use of either UW or HTK solution, as measured by portal venous pressure, bile flow, liver enzymes released into the effluent perfusate, glycerol leakage, and histological examinations. These data were consistent with the transplantation study. Histological damage and enzyme release after 5-day survival were lowest in the HTK flush and subsequent UW storage groups following 18 hours of cold storage; likewise, the 5-day survival was superior following 24 hours of cold storage. In conclusion, the combined use of HTK solution for initial graft rinse and subsequent storage in UW solution resulted in a cumulative protection. Choosing low-viscosity HTK solution for the initial organ flush may represent a feasible improvement in liver preservation, which also further reduces the required amount of UW solution.

Evaluation of IGL-1 preservation solution using an orthotopic liver transplantation model

AIM: To compare, in a pig liver transplantation model, the protective effect of UW with that of IGL-1, a high-sodium preservation solution containing polyethylene glycol (PEG) as an oncotic supply.

METHODS: All livers were harvested and grafted orthotopically according to standard techniques. The livers were washed out and preserved for 7 h in IGL-1 (n = 6) or in UW solution (n = 7) at 4°C. In a sham group (n = 4), the livers underwent a 60-min warm ischemia at 37°C. The hepatocellular injury was assessed in organ preservation solution washed out from the graft at the end of ischemic storage (before revascularization), and in serum 2 h after reperfusion and daily for up to 6 d.

RESULTS: Livers preserved in IGL-1 solution released markedly less AST than that preserved in the UW solution before and after revascularization (P < 0.05). Besides, the activity of creatine kinase-BB, a marker of sinusoidal lining cells injury, was higher in the UW group than in the IGL-1 group (P < 0.05). Histological results showed less necrotic regions in livers preserved in IGL-1 solution; however, no difference was observed for inflammation.

CONCLUSION: IGL-1 liquid effectively protects parenchymal and non-parenchymal cells against prese-rvation-reperfusion injuries.

Impact of Organ Preservation Using HTK for Graft Flush and Subsequent Storage in UW in Rat Kidney Transplantation

BACKGROUND

In kidney transplantation, preservation has a significant influence on organ function. Since previous reports have indicated a benefit of combining histidine-tryptophan-ketoglutarate (HTK) and University of Wisconsin (UW) solution, we evaluated the effects of initial flush with low viscosity HTK, followed by storage in UW.

MATERIAL AND METHODS

Kidneys from inbred Lewis rats were procured using HTK or UW for initially perfusion and re-flushed after 30 min with either solution. In a third group, after perfusion with HTK, organs were re-flushed with UW. Organs were stored for 16-24 h (4 degrees C). Study parameters were high-energy phosphates, histology, apoptosis, recipient survival and urine excretion of 15-F2t -isoprostanes (oxidative stress marker).

RESULTS

Prior to transplantation, tissue ATP/ADP concentrations were: HTK/UW > UW-only > HTK-only. In transplanted kidneys, histological damage was highest after preservation in HTK-only. Twenty-four hours after transplantation (24 h cold ischemia time - CIT), cleaved-PARP was most abundant using UW-only. 16 h of CIT resulted in higher urine concentrations of isoprostanes in the order HTK-only (368 +/- 308) > UW-only (157 +/- 105) > HTK/UW (67 +/- 26), and was lower in HTK/UW after 24 h of CIT (146 +/- 38) vs. UW-only (507 +/- 33 pg/mg creatinine). Survival (24 h CIT) was significantly reduced, and percentage of initial non-functioning (INF) kidneys highest in HTK-only (2.6 +/- 0.3 days, 100%), compared to UW-only (13 +/- 4.4 days, 75%) and HTK/UW (18.5 +/- 4.6 days, 33%).

CONCLUSIONS

In long-term preservation, UW is superior over HTK. However, our results indicate that perfusion with HTK prior to storage in UW may improve the results of UW alone which is reflected by better survival, lower rate of INF, higher cellular energy conservation and a decrease of free radicals.

Machine perfusion preservation of the pig liver using a new preservation solution, polysol

INTRODUCTION

The current gold standard for donor liver preservation is cold storage in a preservation solution (4 degrees C), such as Celsior or the University of Wisconsin solution (UW). Recent studies have suggested the benefits of machine perfusion (MP) over cold storage. To improve the results of MP, an enriched preservation solution (named Polysol) was developed, which in a rat liver preservation model proved to be superior to the UW-gluconate solution. The aim of this study was to assess Polysol in a pig liver preservation model.

MATERIALS AND METHODS

Female pigs (35 to 40 kg) were used as liver donors. After heparinization, the liver was washed out using Ringer's lactate, followed by the preservation solution (4 degrees C). The liver was preserved for 24 hours by either cold storage using Celsior (n=5) or MP using Polysol (n=5). For analysis of liver damage and function, livers were reperfused for 60 minutes using oxygenated Krebs-Henseleit buffer.

RESULTS

CS-Celsior caused significantly more damage compared with MP-Polysol (t=60, AST: 622+/-215 versus 222+/-55; ALT: 17+/-6 versus 5+/-1). Intravascular resistance during reperfusion was significantly higher after CS-Celsior compared with MP-Polysol (t=0, 0.20+/-0.01 and 0.11+/-0.02 mm Hg/mL/min, respectively). No differences were seen regarding ammonia clearance and urea production. In both groups, no bile was produced during reperfusion.

CONCLUSIONS

In an ex vivo pig liver preservation model significantly less damage was observed after machine perfusion preservation using Polysol, in comparison to cold storage using Celsior.

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.

Follow-up experience using histidine-tryptophan ketoglutarate solution in clinical pancreas transplantation

In May 2003, at Indiana University, the standard cold preservation solution University of Wisconsin (UW) solution was replaced by histidine-tryptophan ketogluatarate (HTK) solution. Earlier, we presented our initial experience with HTK in pancreas preservation with an analysis of the first 10 pancreas transplants. Here we report updated results with HTK in pancreas transplantation over the past 18 months. Between May 2003 and March 2005, a total of 87 pancreas transplants were performed with 78 of these organs utilizing HTK. Seventy five patients received 78 organ transplants. Surgical procedures performed were: simultaneous kidney pancreas transplantation (n = 50, 64%), pancreas after kidney transplantation (n = 19, 24%), solitary pancreas transplantation (n = 9, 12%). Donor and recipient data were collected with primary outcomes as primary nonfunction and 30-day graft and patient survivals, and compared to the UW cohort from our original report. Donor and recipient demographics were similar. Mean follow-up time is 12 +/- 6 months. The mean cold ischemia time was 9 +/- 3 hours. There were no cases of primary graft nonfunction. Thirty-day and 1-year patient survivals were 99% and 93%. The 30-day and 1-year graft survivals were 96% and 93%. There were five grafts lost, including three within the first month (two venous and one arterial thrombosis). There was one case of chronic rejection and one noncompliance. All other patients were insulin-independent by discharge. Serum fasting blood glucose and serial amylase remained comparable at all intervals posttransplantation. Within this range of cold ischemia time, HTK appears to provide effective pancreas preservation.

24-h storage of pig livers in UW, HTK, hydroxyethyl starch, and saline solution: is microdialysis an appropriate method for the continuous graft monitoring during preservation?

Recent studies demonstrate the feasibility of microdialysis to monitor metabolism in ischemic livers. Whether these parameters correlate with markers of liver cell integrity in an experimental model using pig livers and different preservation solutions was an aim of this study. Pig livers were flushed with either 4 degrees C Histidine-Typtophan-Ketoglutarate solution (HTK) (Custodiol), University of Wisconsin solution (ViaSpan), and hydroxyethyl starch, or 12 degrees C saline solution. After 24-h storage, the livers were rinsed with saline to measure liver enzymes and lactate from the effluate. Utilizing microdialysis, intraparenchymal lactate, pyruvate, glucose, and glycerol was monitored. Tissue biopsies were taken for histological examinations. Cold preservation resulted in a decrease of metabolic activity measured by intrahepatic glucose, lactate, and pyruvate levels, as well as lactate in the effluate, independently of the solution used. Of particular interest, glycerol levels partially reflected the extent of hepatocellular damage and liver enzyme release. Glycerol levels partially discriminated preservation of different quality and were in accordance to histological findings and liver enzyme release. Lactate, pyruvate, and glucose levels were not appropriate as markers during cold storage. Whether or not glycerol monitoring could represent an additional and rational complementation to the current practice of macroscopic, microscopic and donor evaluation has to be clarified by further studies.

Safety and efficacy of living donor liver preservation with HTK solution

BACKGROUND

In living donor liver transplantation (LDLTx) organ procurement is usually well controlled, and allows to assess liver preservation and graft function under standardized conditions. Because publications on histidine-tryptophan-ketoglutarate (HTK) solution are limited, we prospectively studied its safety and efficacy in a consecutive series of LDLTx.

METHODS

Twenty-four patients received 22 right, 1 left, and 1 left lateral lobe graft. Liver preservation was done by gravity perfusion with HTK through portal vein, and hepatic artery, and flushing of bile ducts. Total ischemia time was 191 +/- 68 minutes.

RESULTS

There was no primary nonfunction, and all partial liver grafts showed good recovery: peak aspartate aminotransferase 577 U/L, total bilirubin 15.15 mg/dL, and partial thromboplastin time 49.37 seconds. One graft was lost from parenchymal fracture secondary to portal hyperperfusion after 6 days, and the patient was salvaged with retransplantation. Thirty-day mortality, including sudden cardiac death, pancreatitis, and hepatic artery rupture, was not related to graft dysfunction. Eight of 24 recipients developed early biliary leakage. There was no late ischemic type biliary lesion.

CONCLUSION

These results confirm that HTK solution is safe and effective when used in LDLTx. Potential advantages of HTK in comparison to other preservation solutions are low potassium concentration, low viscosity, no particles, in situ perfusion, no need to flush before reperfusion, improved biliary protection, better recovery of microcirculatory changes, ready to use, and lower costs. Because the risk-benefit ratio is of particular importance in LDLTx the use of HTK solution should be encouraged.

Optimization of conditions for clinical human hepatocyte infusion

Cytotoxicity and apoptosis are common problems in the isolation and storage of human hepatocytes. In vitro environments of hepatocytes during cell infusion may be critical to reducing cellular damage and enhancing cell viability. We examined the effects of donor liver histology (40-50% steatosis vs. normal), incubation time, temperature, and three solutions for infusion on banked primary human hepatocytes, by studying: trypan blue exclusion, AST release, LDH release, MTT assay, detection of DNA ladder, and a hepatocyte proliferation assay. In addition, the microstructure functions of the endoplasmic reticulum and mitochondria of the intact hepatocytes were determined by measuring correlates of UGT 1A1 and cytochrome P-450 3A (CYP3A4) activity. In general, hepatocyte viability decreased significantly within 60 min after thawing. Cells suspended in 5% dextrose lactated Ringers solution (D5LR) maintained greater cell viability. Hepatocytes from normal liver donors showed less AST and LDH enzyme leak in comparison with cells from fatty liver donors. Mild hypothermic temperature (32 degrees C) inhibited cellular damage that otherwise significantly increased at 60 min. Hepatocytes did not proliferate until 12 h from thaw, regardless of supernatant or conditions of suspension. CYP3A4 activity and a marker for UGT 1A1 activity in hepatocytes from normal donor livers were higher than those from steatotic donor livers. These findings suggest that hepatocytes suspended for infusion after isolation from normal liver donors have normal biological functions and less cellular damage/necrosis in contrast with those isolated from fatty liver donors. These damages are inhibited significantly by maintaining hepatocytes at a mild hypothermic temperature (32 degrees C). D5LR alone maintained the best cell viability for up to 60 min. Media of D5LR + adenosine and HMM were able to partially inhibit hepatocyte apoptosis in hepatocytes from steatotic livers.

LIVER GRAFTS PRESERVED IN CELSIOR SOLUTION AS SOURCE OF HEPATOCYTES FOR DRUG METABOLISM STUDIES: COMPARISON WITH SURGICAL LIVER BIOPSIES

Suitability of human liver grafts preserved in Celsior solution (CS) for preparing metabolically competent hepatocyte cultures has been examined. To this end, basal and induced activity and mRNA levels of major hepatic cytochrome P450 (P450) enzymes have been measured. By 24 h in culture, measurable levels of the 10 P450 mRNAs studied were found in all hepatocyte preparations examined, with CYP2E1, CYP2C9, and CYP3A4 mRNAs being the most abundant. Compared with hepatocytes obtained from surgical liver resections (SLRs), lower content of each P450 mRNA was found in hepatocytes from the CS group; however, the relative distribution of individual P450 mRNAs was similar. Similar results were observed after measuring P450 activities. CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2E1, and CYP3A4 activities in hepatocytes from CS-flushed grafts were lower than but comparable with those of cultures prepared from SLRs. No differences in the metabolite profile of testosterone were found. Treatment of hepatocytes from CS-preserved grafts with model P450 inducers shows that 2 microM methylcholanthrene only increased CYP1A1 and CYP1A2 mRNAs (>100-fold over control), 1 mM phenobarbital markedly increased CYP2A6, CYP2B6, and CYP3A4 mRNA content (>7-fold), and 50 microM rifampicin highly increased CYP3A4 mRNA levels (>10-fold), whereas minor effects (<3-fold) were observed in CYP2A6, CYP2B6, and CYP2C9 mRNAs. This induction pattern of P450s was similar, in terms of magnitude, reproducibility, and specificity, to that shown in primary hepatocytes from surgical biopsies. Overall, our results indicate that, cold-preserved in CS, liver grafts constitute a valuable source of human hepatocytes for drug metabolism studies.

A comparative prospective study of two available solutions for kidney and liver preservation

BACKGROUND

Viaspan (University of Wisconsin [UW]) solution is the gold standard for abdominal organ preservation. Celsior (CEL) is an extracellular-type, low-potassium, low-viscosity solution, initially used for heart and lung preservation. We have performed a prospective multicenter study to compare the role of these cold-storage solutions on kidney and liver recovery after transplantation.

PATIENTS AND METHODS

From March 15, 2000 to December 31, 2001, 441 (172 CEL and 269 UW) renal transplants (RT) and 175 (79 CEL and 96 UW) liver transplants (LT) were included in the study.

RESULTS

Perfusate volume used was significantly lower in the UW group, being 4,732 +/- 796 mL versus 5,826 + 834 mL in the CEL group (P < 0.001). In LT, median total bilirubin serum levels were significantly higher at 5 and 7 posttransplant days in the UW group (90.6 and 92.3 micromol/L, respectively) as compared with CEL (51.3 and 63.4 micromol/L, respectively). After LT, primary nonfunction (PNF) rates in the CEL and UW groups were 3.8% and 4.2% (P = NS) respectively, with 1-year graft and patient survival being 83.3% versus 85.4% (P = NS) and 89.9% versus 90.6% (P = NS). After RT, delayed graft function (DGF) rates were 23.2% and 22.7% (P = NS), respectively; PNF rates were 1.9% and 1.7% (P = NS) respectively, with 1-year graft and patient survival being 92.3% versus 94.2% (P = NS) and 99.4% versus 97.7% (P = NS).

CONCLUSIONS

CEL solution was shown to be as effective as UW in both liver and kidney preservation. In LT patients, biliary function recovery is significantly better in the CEL group. CEL solution represents an efficacious option in multiorgan harvesting.

The utility of marginal donors in liver transplantation

The shortage of organs has led centers to expand their criteria for the acceptance of marginal donors. The combination of multiple marginal factors seems to be additive on graft injury. In this review, the utility of various marginal donors in patients requiring liver transplantation will be described, including older donors, steatotic livers, non-heart-beating donors, donors with viral hepatitis, and donors with malignancies. The pathophysiology of the marginal donor will be discussed, along with strategies for minimizing the ischemia reperfusion injury experienced by these organs. Finally, new strategies for improving the function of the marginal/expanded donor liver will be reviewed.