Experimental evaluation of Celsior, a new heart preservation solution

Cold ischemia time in liver transplantation: An overview

The standard approach to organ preservation in liver transplantation is by static cold storage and the time between the cross-clamping of a graft in a donor and its reperfusion in the recipient is defined as cold ischemia time (CIT). This simple definition reveals a multifactorial time frame that depends on donor hepatectomy time, transit time, and recipient surgery time, and is one of the most important donor-related risk factors which may influence the graft and recipient’s survival. Recently, the growing demand for the use of marginal liver grafts has prompted scientific exploration to analyze ischemia time factors and develop different organ preservation strategies. This review details the CIT definition and analyzes its different factors. It also explores the most recent strategies developed to implement each timestamp of CIT and to protect the graft from ischemic injury.

Steatotic Donor Transplant Livers: Preservation Strategies to Mitigate against Ischaemia-Reperfusion Injury

Liver transplantation (LT) is the only definitive treatment for end-stage liver disease, yet the UK has seen a 400% increase in liver disease-related deaths since 1970, constrained further by a critical shortage of donor organs. This shortfall has necessitated the use of extended criteria donor organs, including those with evidence of steatosis. The impact of hepatic steatosis (HS) on graft viability remains a concern, particularly for donor livers with moderate to severe steatosis which are highly sensitive to the process of ischaemia-reperfusion injury (IRI) and static cold storage (SCS) leading to poor post-transplantation outcomes. This review explores the pathophysiological predisposition of steatotic livers to IRI, the limitations of SCS, and alternative preservation strategies, including novel organ preservation solutions (OPS) and normothermic machine perfusion (NMP), to mitigate IRI and improve outcomes for steatotic donor livers. By addressing these challenges, the liver transplant community can enhance the utilisation of steatotic donor livers which is crucial in the context of the global obesity crisis and the growing need to expand the donor pool.

CPA toxicity screening of cryoprotective solutions in rat hearts

In clinical practice, donor hearts are transported on ice prior to transplant and discarded if cold ischemia time exceeds ∼5 h. Methods to extend these preservation times are critically needed, and ideally, this storage time would extend indefinitely, enabling improved donor-to-patient matching, organ utilization, and immune tolerance induction protocols. Previously, we demonstrated successful vitrification and rewarming of whole rat hearts without ice formation by perfusion-loading a cryoprotective agent (CPA) solution prior to vitrification. However, these hearts did not recover any beating even in controls with CPA loading/unloading alone, which points to the chemical toxicity of the cryoprotective solution (VS55 in Euro-Collins carrier solution) as the likely culprit. To address this, we compared the toxicity of another established CPA cocktail (VEG) to VS55 using ex situ rat heart perfusion. The CPA exposure time was 150 min, and the normothermic assessment time was 60 min. Using Celsior as the carrier, we observed partial recovery of function (atria-only beating) for both VS55 and VEG. Upon further analysis, we found that the VEG CPA cocktail resulted in 50 % lower LDH release than VS55 (N = 4, p = 0.017), suggesting VEG has lower toxicity than VS55. Celsior was a better carrier solution than alternatives such as UW, as CPA + Celsior-treated hearts spent less time in cardiac arrest (N = 4, p = 0.029). While we showed substantial improvement in cardiac function after exposure to vitrifiable concentrations of CPA by improving both the CPA and carrier solution formulation, further improvements will be required before we achieve healthy cryopreserved organs for transplant.

How to Preserve Steatotic Liver Grafts for Transplantation

Liver allograft steatosis is a significant risk factor for postoperative graft dysfunction and has been associated with inferior patient and graft survival, particularly in the case of moderate or severe macrovesicular steatosis. In recent years, the increasing incidence of obesity and fatty liver disease in the population has led to a higher proportion of steatotic liver grafts being used for transplantation, making the optimization of their preservation an urgent necessity. This review discusses the mechanisms behind the increased susceptibility of fatty livers to ischemia-reperfusion injury and provides an overview of the available strategies to improve their utilization for transplantation, with a focus on preclinical and clinical evidence supporting donor interventions, novel preservation solutions, and machine perfusion techniques.

Abdominal Organ Preservation Solutions in the Age of Machine Perfusion

The past decade has been the foreground for a radical revolution in the field of preservation in abdominal organ transplantation. Perfusion has increasingly replaced static cold storage as the preferred and even gold standard preservation method for marginal-quality organs. Perfusion is dynamic and offers several advantages in comparison with static cold storage. These include the ability to provide a continuous supply of new metabolic substrates, clear metabolic waste products, and perform some degree of organ viability assessment before actual transplantation in the recipient. At the same time, the ongoing importance of static cold storage cannot be overlooked, in particular when it comes to logistical and technical convenience and cost, not to mention the fact that it continues to work well for the majority of transplant allografts. The present review article provides an overview of the fundamental concepts of organ preservation, providing a brief history of static cold preservation and description of the principles behind and basic components of cold preservation solutions. An evaluation of current evidence supporting the use of different preservation solutions in abdominal organ transplantation is provided. As well, the range of solutions used for machine perfusion of abdominal organs is described, as are variations in their compositions related to changing metabolic needs paralleling the raising of the temperature of the perfusate from hypothermic to normothermic range. Finally, appraisal of new preservation solutions that are on the horizon is provided.

Therapeutic Inhibition of Acid Sensing Ion Channel 1a Recovers Heart Function After Ischemia-Reperfusion Injury

Background: Ischemia-reperfusion injury (IRI) is one of the major risk factors implicated in morbidity and mortality associated with cardiovascular disease. During cardiac ischemia, the build-up of acidic metabolites results in decreased intracellular and extracellular pH that can reach as low as 6.0-6.5. The resulting tissue acidosis exacerbates ischemic injury and significantly impacts cardiac function. Methods: We used genetic and pharmacological methods to investigate the role of acid sensing ion channel 1a (ASIC1a) in cardiac IRI at the cellular and whole organ level. Human induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) as well as ex vivo and in vivo models of IRI were used to test the efficacy of ASIC1a inhibitors as pre- and post-conditioning therapeutic agents. Results: Analysis of human complex trait genetics indicate that variants in the ASIC1 genetic locus are significantly associated with cardiac and cerebrovascular ischemic injuries. Using hiPSC-CMs in vitro and murine ex vivo heart models, we demonstrate that genetic ablation of ASIC1a improves cardiomyocyte viability after acute IRI. Therapeutic blockade of ASIC1a using specific and potent pharmacological inhibitors recapitulates this cardioprotective effect. We used an in vivo model of myocardial infarction (MI) and two models of ex vivo donor heart procurement and storage as clinical models to show that ASIC1a inhibition improves post-IRI cardiac viability. Use of ASIC1a inhibitors as pre- or post-conditioning agents provided equivalent cardioprotection to benchmark drugs, including the sodium-hydrogen exchange inhibitor zoniporide. At the cellular and whole organ level, we show that acute exposure to ASIC1a inhibitors has no impact on cardiac ion channels regulating baseline electromechanical coupling and physiological performance. Conclusions: Collectively, our data provide compelling evidence for a novel pharmacological strategy involving ASIC1a blockade as a cardioprotective therapy to improve the viability of hearts subjected to IRI.

Celsior® crystalloid cardioplegia versus standard hyperkalemic normothermic blood cardioplegia: Analysis of myocardial protection in elective mitral valve repair

INTRODUCTION

With the increase and refinement of video assisted mitral valve surgery, cristalloïd cardioplegia started regaining popularity. The aim of our study was to evaluate the effectiveness of Celsior^®, a crystalloid cardioplegic solution, on myocardial protection in elective surgical mitral valve repair in comparison to blood based hyperkalemic cardioplegia.

METHODS

In this observational retrospective study, all consecutive elective isolated surgical mitral valve repair where Celsior^® or normothermic hyperkalemic blood cardioplegia were used were included. Primary endpoint was any sign of myocardial protection failure (troponin levels, need for inotropic or mechanical support, rhythm disturbances, mortality). Secondary endpoint was Celsior^® safety (allergic reactions, bleeding, organ toxicities).

RESULTS

From January 2009 to August 2016, 382 patients underwent elective isolated mitral valve repair in whom normothermic hyperkalemic blood cardioplegia (n = 181) or Celsior^® (n = 201) were used. There were no statistically significant differences in baseline characteristics including Euroscore 2. Peak troponin (pg/ml) release and 30-days mortality were not statistically different. Need for cardioversion was significantly more frequent in the Celsior^® group (47% vs 13%, p < 0.001). There was no statistical difference in post-operative atrial fibrillation, permanent pacemaker implantation, reoperation for bleeding, transfusion, acute kidney injury, haemoglobin at discharge or length of stay. No allergic reaction to Celsior^® occurred.

CONCLUSION

Effective myocardial protection was achieved with the Celsior^® cardioplegic solution with no unexpected toxicity. Celsior^® may be an efficacious and safe cardioprotective strategy in mitral valve repair.

Bardallo R, Calvo M, Folch-Puy E, Carbonell T, Palmeira C, Roselló Catafau J, Adam R. Polyethylene Glycol 35 as a Perfusate Additive for Mitochondrial and Glycocalyx Protection in HOPE Liver Preservation

Organ transplantation is a multifactorial process in which proper graft preservation is a mandatory step for the success of the transplantation. Hypothermic preservation of abdominal organs is mostly based on the use of several commercial solutions, including UW, Celsior, HTK and IGL-1. The presence of the oncotic agents HES (in UW) and PEG35 (in IGL-1) characterize both solution compositions, while HTK and Celsior do not contain any type of oncotic agent. Polyethylene glycols (PEGs) are non-immunogenic, non-toxic and water-soluble polymers, which present a combination of properties of particular interest in the clinical context of ischemia-reperfusion injury (IRI): they limit edema and nitric oxide induction and modulate immunogenicity. Besides static cold storage (SCS), there are other strategies to preserve the organ, such as the use of machine perfusion (MP) in dynamic preservation strategies, which increase graft function and survival as compared to the conventional static hypothermic preservation. Here we report some considerations about using PEG35 as a component of perfusates for MP strategies (such as hypothermic oxygenated perfusion, HOPE) and its benefits for liver graft preservation. Improved liver preservation is closely related to mitochondria integrity, making this organelle a good target to increase graft viability, especially in marginal organs (e.g., steatotic livers). The final goal is to increase the pool of suitable organs, and thereby shorten patient waiting lists, a crucial problem in liver transplantation.

Preservation Solutions for Kidney Transplantation: History, Advances and Mechanisms

Solid organ transplantation was one of the greatest medical advances during the past few decades. Organ preservation solutions have been applied to diminish ischemic/hypoxic injury during cold storage and improve graft survival. In this article, we provide a general review of the history and advances of preservation solutions for kidney transplantation. Key components of commonly used solutions are listed, and effective supplementations for current available preservation solutions are discussed. At cellular and molecular levels, further insights were provided into the pathophysiological mechanisms of effective ingredients against ischemic/hypoxic renal injury during cold storage. We pay special attention to the cellular and molecular events during transplantation, including ATP depletion, acidosis, mitochondrial dysfunction, oxidative stress, inflammation, and other intracellular mechanisms.

Organ preservation solutions: linking pharmacology to survival for the donor organ pathway

PURPOSE OF REVIEW

To provide an understanding of the scientific principles, which underpinned the development of organ preservation solutions, and to bring into context new strategies and challenges for solution development against the background of changing preservation technologies and expanded criteria donor access.

RECENT FINDINGS

Improvements in organ preservation solutions continue to be made with new pharmacological approaches. New solutions have been developed for dynamic perfusion preservation and are now in clinical application. Principles defining organ preservation solution pharmacology are being applied for cold chain logistics in tissue engineering and regenerative medicine.

SUMMARY

Organ preservation solutions support the donor organ pathway. The solution compositions allow additives and pharmacological agents to be delivered direct to the target organ to mitigate preservation injury. Changing preservation strategies provide further challenges and opportunities to improve organ preservation solutions.

Myocardial protection in on-pump coronary artery bypass grafting surgery: analysis of the effectiveness of the use of retrograde Celsior®

BACKGROUND

We analyzed the adequacy of the myocardial protection achieved with a single dose of retrograde crystalloid Celsior®, compared with an accepted standard (microplegia), in on-pump coronary artery bypass grafting surgery (CABG).

METHODS

This was a retrospective comparative clinical study conducted in a single institution that included all the patients operated on who had elective isolated on-pump CABG, from March 2006 to June 2014. We evaluated maximum postoperative troponin T (TnT) as a marker of myocardial damage, adjusted for possible confounders using propensity score matching. We also analyzed markers of recovery of myocardial function, and the safety of the intravenous use of Celsior®.

RESULTS

During the study period, 261 patients were included, divided in two groups: (a) continuous retrograde blood-based microplegia (114 patients); (b) retrograde single-dose crystalloid Celsior® (147 patients). The propensity score adjusted maximum TnT was significantly lower in the Celsior group [average treatment effect = -0.55 ng/dl; 95% confidence interval (CI) -1.10 to -0.1 ng/dl; p = 0.048]. There were no differences in the postoperative use of intra-aortic balloon of counterpulsation or in the requirements of high-dose inotropic medications. In-hospital mortality was equivalent in both study groups ( p = 0.73); surgical re-exploration because of bleeding was equivalent ( p = 0.37). There were no differences in prolonged mechanical ventilation ( p = 0.65) and intensive care unit length of stay ( p = 0.87).

CONCLUSION

An isolated single dose of retrograde Celsior® may be an effective and safe myocardial protection strategy in on-pump CABG.

Systematic review of preservation solutions for allografts for liver transplantation based on a network meta-analysis

AIMS

The aim of this work was to determine the best preservation solutions for allografts for liver transplantation by quantitative network meta-analysis.

METHODS

Global electronic databases including PubMed, EMBASE, and Cochrane Library were searched for relevant randomized controlled trials. Seven pieces of parametric data were extracted from included studies for pooled estimation. A consistency model was used for direct and indirect comparisons. The cumulative probability P value was utilized to rank the solutions. A node-splitting model was utilized for testing the consistency of final data. Quality of evidence was assessed using the GRADE (Grades of Recommendations Assessment, Development and Evaluation) system.

RESULTS

Eleven 2-arm trials including 1319 patients and 5 different solutions were finally included. HTK (Histidine-tryptophan-ketoglutarate) solution exhibited the best efficacy for decreasing the primary dysfunction rate, biliary complications and ICU-stay time (probability P = 0.43, 0.45 and 0.58, respectively). Celsior solution significantly decreased the rate of rejection and early retransplantation (probability P = 0.73 and 0.38, respectively), and enhanced patient and graft survival (probability P = 0.90 and 0.98, respectively) more than did other solutions. Overall, the quality of evidence was rated high or moderate.

CONCLUSIONS

We suggested that HTK solution may offer the best safety during the perioperative period. However, Celsior solution led to better graft tolerance and exhibited greater benefit for long-term outcomes. And our conclusions still need to be further validated.

Tissue conservation for transplantation

Pathophysiological changes that occur during ischemia and subsequent reperfusion cause damage to tissues procured for transplantation and also affect long-term allograft function and survival. The proper preservation of organs before transplantation is a must to limit these injuries as much as possible. For decades, static cold storage has been the gold standard for organ preservation, with mechanical perfusion developing as a promising alternative only recently. The current literature points to the need of developing dedicated preservation protocols for every organ, which in combination with other interventions such as ischemic preconditioning and therapeutic additives offer the possibility of improving organ preservation and extending it to multiple times its current duration. This review strives to present an overview of the current body of knowledge with regard to the preservation of organs and tissues destined for transplantation.

Retrospective Clinical Comparison of Celsior Solution to Modified Blood Wallwork Solution in Lung Transplantation for Cystic Fibrosis

Objective

To compare the preservative effects of Celsior solution and modified blood Wallwork solution in lung transplantation.

Methods

From 1989 to 2000, 44 lung transplantations for cystic fibrosis were performed: 26 grafts were preserved with modified blood Wallwork solution and 18 with Celsior solution.

Results

Preoperative status of the 2 groups was similar. The ratio of arterial oxygen to fraction of inspired oxygen and the pulmonary vascular resistance on the first postoperative day did not differ significantly between the 2 groups. Early death was 4% (SD, 20%) in the Wallwork group versus 11% (SD, 32%) in the Celsior group (not significant). No death was related to graft failure. The forced expiratory volume in 1 second during the first month after transplantation was 63% (SD, 19%) in the Wallwork group versus 63% (SD, 16%) in the Celsior group (not significant).

Conclusion

Because the solution does not need to be prepared on site and does not require blood from the donor, Celsior seems better than Wallwork solution for preserving lung grafts.

Potential benefits of melatonin in organ transplantation: a review

Organ transplantation is a useful therapeutic tool for patients with end-stage organ failure; however, graft rejection is a major obstacle in terms of a successful treatment. Rejection is usually a consequence of a complex immunological and nonimmunological antigen-independent cascade of events, including free radical-mediated ischemia-reperfusion injury (IRI). To reduce the frequency of this outcome, continuing improvements in the efficacy of antirejection drugs are a top priority to enhance the long-term survival of transplant recipients. Melatonin (N-acetyl-5-methoxytryptamine) is a powerful antioxidant and ant-inflammatory agent synthesized from the essential amino acid l-tryptophan; it is produced by the pineal gland as well as by many other organs including ovary, testes, bone marrow, gut, placenta, and liver. Melatonin has proven to be a potentially useful therapeutic tool in the reduction of graft rejection. Its benefits are based on its direct actions as a free radical scavenger as well as its indirect antioxidative actions in the stimulation of the cellular antioxidant defense system. Moreover, it has significant anti-inflammatory activity. Melatonin has been found to improve the beneficial effects of preservation fluids when they are enriched with the indoleamine. This article reviews the experimental evidence that melatonin is useful in reducing graft failure, especially in cardiac, bone, otolaryngology, ovarian, testicular, lung, pancreas, kidney, and liver transplantation.

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.

Hypothermic Oxygenated Liver Perfusion: Basic Mechanisms and Clinical Application

Dynamic preservation strategies such as hypothermic machine perfusion are increasingly discussed to improve liver graft quality before transplantation. This review summarizes current knowledge of this perfusion technique for liver preservation. We discuss optimization of perfusion conditions and current strategies to assess graft quality during cold perfusion. Next, we provide an overview of possible pathways of protection from ischemia-reperfusion injury. Finally, we report on recent clinical applications of human hypothermic machine liver perfusion.

Preservation solution impacts physiologic function and cellular viability of human saphenous vein graft

INTRODUCTION

Recent clinical data suggest intraoperative preservation of human saphenous vein (HSV) in normal saline is associated with vein graft failure. We evaluated the influence of several preservation media on acute physiologic function and cellular viability of HSV conduit.

METHODS

Unprepared (UP) HSV obtained from coronary artery bypass graft patients was characterized on a muscle bath after 2-hour storage in 6 solutions: Plasma-Lyte A, 0.9% NaCl (normal saline), University of Wisconsin solution, Celsior solution, autologous whole blood, or glutathione-ascorbic acid L-arginine (GALA) solution. Vascular smooth muscle contractility was assessed after exposure to depolarizing KCl and phenylephrine. The relaxation of phenylephrine-precontracted HSV to sodium nitroprusside and carbachol (endothelial-independent and -dependent relaxation, respectively) was also assessed. Cellular viability was determined via the methyl thiazolyl tetrazolium (MTT) assay. Rat aortae were used to assess the effect of pH during graft preservation on endothelial-dependent relaxation.

RESULTS

Preservation of HSV in normal saline and autologous whole blood impaired contractile responses to KCl relative to UP tissues, whereas preservation in University of Wisconsin solution and Celsior solution enhanced contractile responses (P < .05). Relative to UP tissues, responses to phenylephrine were decreased with preservation in normal saline, whereas preservation in University of Wisconsin solution, Celsior solution, and GALA all potentiated these responses (P < .05). Only preservation in normal saline impaired endothelial-independent relaxation (P = .005). Preservation in Plasma-Lyte A (P = .02), normal saline (P = .002), and University of Wisconsin solution (P = .02) impaired endothelial-dependent relaxation. Normal saline preservation decreased MTT viability index relative to UP tissues (0.02 ± 0.002 mg(-1)0.5 mL(-1) vs 0.033 ± 0.005 mg(-1)0.5 mL(-1); P = .03). Endothelial function was impaired by acidic pH in rat aorta.

CONCLUSION

Preservation of HSV in normal saline causes graft injury leading to impaired physiologic function and decreased viability of the HSV. This harm is mitigated by the use of buffered salt solutions as preservation media.

Cardio-protective signalling by glyceryl trinitrate and cariporide in a model of donor heart preservation

BACKGROUND

Storage of donor hearts in cardioplegic solutions supplemented with agents that mimic the ischaemic preconditioning response enhanced their post-reperfusion function. The present study examines the minimisation of cell death and activation of pro-survival signalling directed towards maintenance of mitochondrial homeostasis in hearts arrested and stored in two such agents, glyceryl-trinitrate, a nitric oxide donor and cariporide, (a sodium-hydrogen exchange inhibitor).

METHODS

After baseline functional measurement, isolated working rat hearts were arrested and stored for 6h at 4°C in either Celsior(®), Celsior(®) containing 0.1mg/ml glyceryl-trinitrate, 10μM cariporide or both agents. After reperfusion, function was remeasured. Hearts were then processed for immunoblotting or histology.

RESULTS

Necrotic and apoptotic markers present in the Celsior(®) group post-reperfusion were abolished by glyceryl-trinitrate, cariporide or both. Increased phosphorylation of ERK and Bcl2, after reperfusion in groups stored in glyceryl-trinitrate, cariporide or both along with increased phospho-STAT3 levels in the glyceryl-trinitrate/cariporide group correlated with functional recovery. Inhibition of STAT3 phosphorylation blocked recovery. No phospho-Akt increase was seen in any treatment.

CONCLUSIONS

Activation of signalling pathways that favour mitophagy activation (ERK and Bcl2 phosphorylation) and maintenance of mitochondrial transition pore closure after reperfusion (STAT3 and ERK phosphorylation) were crucial for functional recovery of the donor heart.

Subnormothermic preservation in somah: a novel approach for enhanced functional resuscitation of donor hearts for transplant

Organ preservation at 4°C results in temporally irreversible injury to cellular structure and function. This study was designed to evaluate the possibility of storing hearts at ambient temperatures in novel organ preservation solution Somah to prevent damage and preserve optimum function by maintaining cellular energy over the temperature range of storage. Porcine hearts were stored in Celsior at 4°C and Somah at 4°C, 13°C and 21°C for 5 h thereafter reperfused and reanimated in vitro for 3 h. Heart weights, histopathology, ultrastructure and 2-dimensional echocardiography (2D-Echo) assessments showed preservation of structure in Somah groups. Tissue high-energy phosphate levels in Somah groups after storage were significantly greater than the Celsior hearts (p < 0.05) and highest in the 21°C Somah hearts. Upon reperfusion, myocardial O2 consumption and lactate levels quickly achieved steady state in 21°C hearts, but were delayed in Somah 4/13°C groups and severely depressed in the Celsior group. Inotrope and electroconversion requirements were inversely related to storage temperature. In vitro 2D Echo demonstrated a discordantly attenuated function in the Celsior group, moderate functionality in 4°C Somah group and superior reestablishment of performance in the Somah higher temperature groups. Hearts stored in Somah at 21°C were metabolically and functionally superior to any other groups.

Comparative analysis of preservation method and intermittent perfusion volume on the expression of endothelial and inflammatory markers by coronal artery and myocardium in porcine donor hearts

Although continuous perfusion of donor hearts for preservation during transportation has been widely applied, intermittent perfusion has been suggested as an alternative. The aim of this study was to identify the optimal intermittent perfusion protocol by investigating the effects of perfusion volume on endothelial and inflammatory marker expression by the coronary artery. Donor porcine hearts were perfused with various volumes of Celsior solution supplemented with diazoxide (50, 100, 150, 200, and 250 ml) every 2 h for 30 min each for a 10 h period. The effects on cardiomyocytes and vascular endothelial cell morphology and marker expression were compared to the immersion control group. Whereas an incomplete endothelial cell layer with disorganized connective tissue was observed in the control and 50, 100, and 150 ml intermittent perfusion groups, transmission electron microscopic analysis revealed a complete endothelial cell layer in the intima with an organized subendothelium. A perfusion volume-dependent increase in eNOS expression that coincided with a decrease in ET-1, ICAM-1, vWF, and P-selectin expression was detected (all p < 0.01). Intermittent perfusion with 200 ml of Celsior solution every 2 h conferred protective effects simultaneously to the coronary arteries and myocardium on the porcine donor heart over a clinically relevant preservation period.

Role of hypothermic machine perfusion in liver transplantation

Machine liver perfusion has significantly evolved during the last ten years to optimize extended criteria liver grafts and to address the worldwide organ shortage. This review gives an overview on available ex vivo and in vivo data on hypothermic machine liver perfusion. We discuss also possible protective pathways and show most recent clinical applications of hypothermic machine liver perfusion in human.

A novel glutamate transporter blocker, LL-TBOA, attenuates ischaemic injury in the isolated, perfused rat heart despite low transporter levels

OBJECTIVES

Loss of glutamate from cardiomyocytes during ischaemia may aggravate ischaemia-reperfusion injury in open heart surgery. This may be due to reversal of excitatory amino acid transporters (EAATs). However, the expression of such transporters in cardiomyocytes is ambiguous and quantitative data are lacking. Our objective was to study whether EAATs were expressed in the rat heart and to study whether blocking of transporter operation during cardiac ischaemia could be beneficial.

METHODS

We used TaqMan real-time PCR and immunoisolation followed by western blotting to unequivocally identify EAAT subtypes in rat hearts. We used a novel high-affinity non-transportable competitive inhibitor, named LL-TBOA [(2S,3S)-3-(3-(6-(6-(2-(2-(2-(2-(2-aminoethoxy)ethoxy)-ethoxy)ethoxy) acetamido)hexanamido)- hexanamido)-5-(4-(trifluoromethyl)benzamido)benzyloxy) aspartic acid], to block EAAT-mediated transport during global ischaemia and reperfusion of isolated rat hearts.

RESULTS

Rat hearts expressed EAAT subtypes 1 and 3, while subtypes 2 and 4 were not detected. Hearts were isolated and perfused with 1.6 µM LL-TBOA for 5 min before 30 min of induced global ischaemia and 60 min of reperfusion (n = 8). Control hearts were perfused either with the solvent dimethylsulfoxide 3.5 mM (n = 7) or with no pretreatment (n = 8). Infarct size was evaluated by triphenyl tetrazolium chloride (TTC) staining. LL-TBOA reduced infarct size from 33 ± 14 to 20 ± 5% (mean ± SD) (P = 0.015). Dimethylsulfoxide alone had no effect (35 ± 2%). Reperfusion arrhythmias were reduced by LL-TBOA (P = 0.009), but not by dimethylsulfoxide alone.

CONCLUSION

Rat hearts express EAAT1 and EAAT3, but the mRNA levels are, respectively, ∼ 25 and 200 times lower than in the brain. Addition of LL-TBOA has a beneficial effect against ischaemia-reperfusion injury.

Preservation of human placenta facilitates multicenter studies on the local immune response in normal and aberrant pregnancies

Our standard procedure for phenotypic and functional analysis of immune cells present in the placenta is to isolate leukocytes from the decidua within five hours of the delivery. However, this results in logistical problems with deliveries at night, weekends or in other medical centers. Collecting placentas after complicated pregnancies is even more difficult owing to the low prevalence and the often unscheduled delivery. The aim was to investigate the possibility of preserving the human placenta before phenotypic and functional analysis of decidual lymphocytes. Placentas were obtained after uncomplicated pregnancy. The tissue was divided into two equal parts: decidual lymphocytes from one part were isolated within five hours according to our standard procedure, whereas the other part was preserved in either Celsior(®), a storage solution for solid organ preservation, or phosphate-buffered saline (PBS) for 24h at 4°C before isolation. Overall, the phenotype and functional capacity of decidual lymphocytes isolated within five hours was comparable to decidual lymphocytes isolated after 24-h preservation in Celsior(®) or PBS. Minor differences were found between decidual lymphocytes isolated within five hours and decidual lymphocytes isolated after 24-h preservation in Celsior(®). The results indicate that PBS is sufficient to preserve the placenta for 24h for phenotypical and functional studies. The ability to preserve the placenta will simplify the procedure for the isolation of decidual lymphocytes and makes it easier to analyze tissue from women who deliver during the night, at weekends or in other hospitals, and possibly even women with complicated pregnancies.

Donor risk factors, retrieval technique, preservation and ischemia/reperfusion injury in pancreas transplantation

PURPOSE OF REVIEW

Pancreas transplantation is still hampered by a high incidence of early graft loss, and organ quality concerns result in high nonrecovery/discard rates. Demographic donor characteristics, surgical retrieval strategy, preservation fluid and ischemia time are crucial factors in the process of organ selection and are discussed in this review.

RECENT FINDINGS

The donor shortage is driving an increasing utilization of nonideal organs which would previously have been identified as unsuitable. Recent literature suggests that organs from extended criteria donors - older (>45 years), BMI >30  kg/m(2), and donation after cardiac death (DCD) - can achieve the same graft and patient survival as those from standard criteria donors, with the proviso that the accumulation of risk factors and long ischemic times should be avoided. Visual assessment of the pancreas is advisable before declining/accepting a pancreas. University of Wisconsin represents the gold standard solution; however, histidine-tryptophan-ketoglutarate and Celsior result in equal outcomes if cold ischemia time (CIT) is less than 12  h. Currently in pancreas transplantation, there is no proven effective ischemia/reperfusion injury prophylaxis than trying to keep CIT as short as possible.

SUMMARY

Demographic risk factors, inspection of the pancreas by an experienced surgeon and predicted CIT are crucial factors in deciding whether to accept a pancreas for transplantation. However, there is a need for an improved evidence base to determine where to set the 'cut-off' for unsuitable pancreatic grafts.

Preservation solutions for liver transplantation in adults: celsior versus custodiol: a systematic review and meta-analysis with an indirect comparison of randomized trials

BACKGROUND

The University of Wisconsin (UW) solution has been recognized as the gold standard for liver preservation; however, it possesses some limitations, and other solutions exist for organ preservation. The aim of this study was to compare the liver functions of transplanted grafts that had been stored in Celsior and Custodiol solutions.

METHODS

We searched the MEDLINE, EMBASE, LILACS, Cochrane Central Register of Controlled Trials, and SCIELO databases. We included randomized and quasi-randomized, controlled trials that compared the efficacy and safety of Celsior and Custodiol with UW solution for liver preservation in adults. The factors that were considered for analysis were their impacts on primary dysfunction (primary nonfunction and initial poor function), ischemic-type biliary lesions, and patient and graft survival rates. Because of the lack of direct evidence, an indirect comparison of Celsior and Custodiol was calculated.

RESULTS

We identified 3 randomized controlled trials and 1 quasi-randomized, controlled trial to pool in a meta-analysis of Celsior versus UW solutions. The number of episodes of primary dysfunction was lower in the Celsior group (7.4%) than in the UW group (9.8%), but the difference was not significant (relative risk [RR], 0.68; 95% confidence interval [CI], 0.22-1.97). Two randomized controlled trials compared Custodiol and Wisconsin solutions were identified. The number of episodes of primary dysfunction was also lower in the Custodiol group (3.0%) compared with the Wisconsin group (8.4%), but the difference was not significant (RR, 0.36; 95% CI, 0.08-1.70). An indirect comparison using data from the main analysis revealed no difference between the Celsior and Custodiol solutions (RR, 1.88; 95% CI, 0.57-6.16).

CONCLUSION

The Celsior and Custodiol solutions performed similarly to UW solution as preservation solutions in liver transplantation clinical settings.

Successful transplantation of rat hearts subjected to extended cold preservation with a novel preservation solution

Since prolonged cold preservation of the heart deteriorates the outcome of heart transplantation, a more protective preservation solution is required. We therefore developed a new solution, named Dsol, and examined whether Dsol, in comparison to UW, could better inhibit myocardial injury resulting from prolonged cold preservation. Syngeneic heterotopic heart transplantation in Lewis rats was performed after cold preservation with UW or Dsol for 24 or 36 h. In addition to graft survival, myocardial injury, ATP content, and Ca(2+) -dependent proteases activity were assessed in the 24-h preservation group. The cytosolic Ca(2+) concentration of H9c2 cardiomyocytes after 24-h cold preservation was assessed. Dsol significantly improved 7-day graft survival after 36-h preservation. After 24-h preservation, Dsol was associated with significantly faster recovery of ATP content and less activation of calpain and caspase-3 after reperfusion. Dsol diminished graft injury significantly, as revealed by the lower levels of infarction, apoptosis, serum LDH and AST release, and graft fibrosis at 7-day. Dsol significantly inhibited Ca(2+) overload during cold preservation. Dsol inhibited myocardial injury and improved graft survival by suppressing Ca(2+) overload during the preservation and the activation of Ca(2+) -dependent proteases. Dsol is therefore considered a better alternative to UW to ameliorate the outcome of heart transplantation.

Protective effects of hypothermic ex vivo perfusion on ischemia/reperfusion injury and transplant outcomes

Hypothermic machine preservation (HMP) has been used in renal transplantation since the late 1960s with recent robust prospective, multicenter data showing lower rates of delayed graft function and improved graft survival. Although now clearly beneficial for renal transplantation, extrarenal machine perfusion has remained predominantly in preclinical investigations. Pancreatic HMP has drawn little clinical interest because HMP has been suggested to cause graft edema and congestion, which is associated with early venous thrombosis and graft failure. Early investigation showed no benefit of HMP in whole-organ pancreas transplant. One report did show that HMP increases islet cell yield after isolation. Preclinical work in liver HMP has been promising. Short- and long-term HMP has been shown to improve graft viability and reduce preservation injury, even in animal models of steatotic and donation after cardiac death. The first clinical study of liver HMP using a centrifugal dual perfusion technique showed excellent results with lower hepatocellular injury markers and no adverse perfusion-related outcomes. In addition, a dramatic attenuation of proinflammatory cytokine expression was observed. Further studies of liver HMP are planned with focus on developing a reproducible and standard protocol that will allow the widespread availability of this technology. Future research and clinical trials of novel organ preservation techniques, solutions, and interventions are likely to bring about developments that will allow further reduction of preservation-related ischemia/reperfusion injury and improved outcomes and allow safer utilization of the precious and limited resource of donor organs.

Celsior versus University of Wisconsin preserving solutions for liver transplantation: postreperfusion syndrome and outcome of a 5-year prospective randomized controlled study

BACKGROUND

Celsior solution (CS) is a high-sodium, low-potassium, low-viscosity extracellular solution that has been used for liver graft preservation in recent years, although experience with it is still limited. We performed an open-label randomized active-controlled trial comparing CS with the University of Wisconsin solution (UW) for liver transplantation (LT), with a follow-up period of 5 years.

METHODS

Adult transplant recipients (n=102) were prospectively randomized to receive either CS (n=51) or UW (n=51). The two groups were comparable with respect to donor and recipient characteristics. The primary outcome measure was the incidence of postreperfusion syndrome (PRS). Secondary outcome measures included primary nonfunction (PNF) or primary dysfunction (PDF), liver retransplantation, and graft and patient survival. Other secondary outcome measures were days in the intensive care unit (ICU) and the rates of acute rejection, chronic rejection, infectious complications, postoperative reoperations, and vascular and biliary complications.

RESULTS

In all, 14 posttransplant variables revealed no significant differences between the groups. There were no cases of PNF or PDF. The incidence of PRS was 5.9% in the CS group and 21.6% in the UW group (P=0.041). After reperfusion, CS revealed greater control of serum potassium (P=0.015), magnesium levels (P=0.005), and plasma glucose (P=0.042) than UW. Respective patient survivals at 3, 12, and 60 months were 95.7, 87.2, and 82.0% for the CS group and 95.7, 83.3, and 66.6% for the UW group (P=0.123).

CONCLUSIONS

While retaining the same degree of safety and effectiveness as UW for LT, CS may yield postliver graft reperfusion benefits, as shown in this study by a significant reduction in the incidence of PRS and greater metabolic control.

Pancreas procurement and preservation for islet transplantation: personal considerations

Pancreatic islet transplantation is a promising option for the treatment of type 1 diabetic patients. After the successful demonstration of the Edmonton protocol, islet transplantation has advanced significantly on several fronts, including improved pancreas procurement and preservation systems. Since we frequently use pancreata from donors after cardiac death in Japan,we have applied the in situ regional organ cooling system for pancreas procurement to reduce the warm ischemic time. To reduce the apoptosis of pancreatic tissue during cold preservation, we have applied the ductal injection of preservation solution. For pancreas preservation, we use modified Kyoto solution, which is advantageous at trypsin inhibition and less collagenase inhibition. In this paper, we show pancreas procurement and preservation in our group for islet transplantation.

Primary graft failure after heart transplantation

Primary graft failure (PGF) is a devastating complication that occurs in the immediate postoperative period following heart transplantation. It manifests as severe ventricular dysfunction of the donor graft and carries significant mortality and morbidity. In the last decade, advances in pharmacological treatment and mechanical circulatory support have improved the outlook for heart transplant recipients who develop this complication. Despite these advances in treatment, PGF is still the leading cause of death in the first 30 days after transplantation. In today's climate of significant organ shortages and growing waiting lists, transplant units worldwide have increasingly utilised "marginal donors" to try and bridge the gap between "supply and demand." One of the costs of this strategy has been an increased incidence of PGF. As the threat of PGF increases, the challenges of predicting and preventing its occurrence, as well as the identification of more effective treatment modalities, are vital areas of active research and development.

Organ storage with University of Wisconsin solution is associated with improved outcomes after orthotopic heart transplantation

BACKGROUND

Despite significant advances in cardiac allograft preservation, the optimal preservative solution is unknown. We evaluated the impact of the most commonly used solutions in the USA, the University of Wisconsin solution (UW) and Celsior solution (CS), on outcomes after orthotopic heart transplantation (OHT).

METHODS

We retrospectively reviewed adult OHT recipients in the United Network for Organ Sharing (UNOS) database. Primary stratification was by preservation solution. The primary end-point was short-term survival (30 days and 1 year). Secondary end-points included common post-operative complications. Subgroup analysis was performed in high-risk allografts (donor age >50 years or ischemic time >4 hours). Risk-adjusted multivariate Cox proportional hazard regression was used to assess survival.

RESULTS

From 2004 to 2009, 4,910 patients (3,107 UW and 1,803 CS) with sufficient preservation solution information for analysis underwent OHT. Baseline characteristics were well-matched between the two groups. UW was associated with a small but significantly improved survival compared with CS at 30 days (96.7% vs 95.4%, p = 0.02) and 1 year (89.6% vs 87.0%, p < 0.01). These survival differences persisted on multivariate analysis at 30 days (HR 1.47 [1.02 to 2.13], p < 0.05) and 1 year (HR 1.40 [1.14 to 1.73], p < 0.01). In the 1,455 patients with high-risk allografts, preservation with UW was associated with improved survival compared with CS at 30 days (94.3% vs 91.3%, p < 0.01) and at 1 year (84.2% vs 80.19%, p < 0.01), a difference that was significant according to multivariate Cox analysis at 30 days (HR 2.29 [1.39 to 3.76], p < 0.01) and 1 year (HR 1.61 [1.17 to 2.21], p < 0.01).

CONCLUSIONS

Preservation with UW solution is associated with improved short-term survival compared with CS. Patients undergoing OHT with high-risk allografts have a similar survival benefit.

Efficacy and safety of Celsior preservation fluid in liver transplantation: one-year follow up of a prospective, multicenter, non-randomized study

The purpose of this prospective, nine-center, non-randomized study was to assess the efficacy and safety of Celsior preservation fluid in liver transplantation using unselected donors. As data comparing allograft outcomes following liver transplantation using Celsior and University of Wisconsin (UW) preservation fluids are limited, we also compared our cohort with matched controls selected from the European Liver Transplant Registry (ELTR) who received total liver grafts preserved with UW solution during the same period. One hundred and forty patients who received livers preserved with Celsior were included. The primary endpoint, graft loss at one-yr post-transplantation, was observed in 24 patients (17.1%) which was not significantly different from the 20.0% pre-defined threshold rate (95% confidence interval [CI] 10.9, 23.4; p=0.398). Predictive factors for graft loss on univariate analysis were moderate-to-severe steatosis on the donor graft (5/22 patients with graft loss vs. 8/107 patients without, p=0.046) and duration of warm ischemia (1.4±1.1 h in patients with graft loss vs. 0.9±0.5 h in patients without, p=0.034). Hepatic artery thrombosis and stenosis occurred in seven (5.0%) and six (4.3%) patients, respectively. The comparison of our patients to 420 ELTR controls showed that one-yr graft survival rates (Celsior: 82.9%, 95% CI 75.8, 88.2; UW: 78.6%, 95% CI 74.4, 82.2) and Kaplan-Meier one-yr graft survival distributions (p=0.285) were similar. Within the cold ischemia time achieved in our study, liver preservation with Celsior appeared efficient and safe. Comparison with ELTR patients suggested that liver allograft survival was similar using Celsior or UW solution for preservation of unselected donor grafts.

Critical role of the STAT3 pathway in the cardioprotective efficacy of zoniporide in a model of myocardial preservation - the rat isolated working heart

BACKGROUND AND PURPOSE

Ischemia-reperfusion injury plays an important role in the development of primary allograft failure after heart transplantation. Inhibition of the Na+/H+ exchanger is one of the most promising therapeutic strategies for treating ischemia-reperfusion injury. Here we have characterized the cardioprotective efficacy of zoniporide and the underlying mechanisms in a model of myocardial preservation using rat isolated working hearts.

EXPERIMENTAL APPROACH

Rat isolated hearts subjected to 6 h hypothermic (1-4°C) storage followed by 45 min reperfusion at 37°C were treated with zoniporide at different concentrations and timing. Recovery of cardiac function, levels of total and phosphorylated protein kinase B, extracellular signal-regulated kinase 1/2, glycogen synthase kinase-3β and STAT3 as well as cleaved caspase 3 were measured at the end of reperfusion. Lactate dehydrogenase release into coronary effluent before and post-storage was also measured.

KEY RESULTS

Zoniporide concentration-dependently improved recovery of cardiac function after reperfusion. The functional recovery induced by zoniporide was accompanied by up-regulation of p-extracellular signal-regulated kinase 1/2 and p-STAT3, and by reduction in lactate dehydrogenase release and cleaved caspase 3. There were no significant differences in any of the above indices when zoniporide was administered before, during or after ischemia. The STAT3 inhibitor, stattic, abolished zoniporide-induced improvements in functional recovery and up-regulation of p-STAT3 after reperfusion.

CONCLUSIONS AND IMPLICATIONS

Zoniporide is a potent cardioprotective agent and activation of STAT3 plays a critical role in the cardioprotective action of zoniporide. This agent shows promise as a supplement to storage solutions to improve preservation of donor hearts.

Superior myocardial preservation with HTK solution over Celsior in rat hearts with prolonged cold ischemia

BACKGROUND

Increasing allograft ischemic time is a significant risk factor for mortality following heart transplantation (HTx). The purpose of this study was to evaluate the protective effects of histidine-tryptophan-ketoglutarate (HTK) and Celsior (CEL) using a rat HTx model with prolonged cold storage.

METHODS

The hearts were excised from donor rats, stored in cold preservation solution for either 6 or 18 hours, and heterotopically transplanted into syngeneic recipients. Serum creatine phosphokinase (CPK), serum troponin I, graft-infiltrating cells, graft mRNA levels for inflammatory mediators, and tissue adenosine triphosphate (ATP) levels were analyzed, as markers of graft injury.

RESULTS

The recipients of grafts stored in HTK for 18 hours of prolonged cold ischemia had lower levels of serum CPK and tissue malondialdehyde, less upregulation of the mRNAs for IL-6 and inducible nitric oxide synthase, less apoptosis, and higher ATP levels than those receiving grafts stored in CEL and Saline. Cardiac contraction 3 hours after reperfusion was observed in 43% of the cardiac grafts stored in HTK for 18 hours, while no cardiac wall movement was seen in grafts stored in either saline or CEL.

CONCLUSION

Cold storage in HTK exhibited superior protective effects against prolonged cold ischemia in a syngeneic rat transplantation model.

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.