Simple Cold Storage Research Articles

Important Constituents of Heavy Water-containing Solution for Cold Storage and Subsequent Reperfusion on an Isolated Perfused Rat Liver

The University of Wisconsin (UW) solution is the most effective preservation solution currently used; however, to safely use expanded-criteria donor grafts, a new cold storage solution that alleviates graft injury more effectively is required. We prepared a heavy water (D2O)-containing buffer, Dsol, and observed strong protective effects during extended cold storage of rat hearts and livers. In the current study, we modified Dsol (mDsol) and tested its efficacy. The aim of the present study was to determine whether mDsol could protect the rat liver more effectively than the UW solution and to clarify the roles of D2O and deferoxamine (DFX). Rat livers were subjected to cold storage for 48 hours in test solutions: UW, mDsol, mDsol without D2O or DFX (mDsol-D2O[-], mDsol-DFX[-]), and subsequently reperfused on an isolated perfused rat liver for 90 minutes at 37°C. In the UW group, the liver was dehydrated during cold storage and rapidly expanded during reperfusion. Accordingly, the cumulative weight change was the highest in the UW group, together with augmented portal veinous resistance and ALT leakage and decreased oxygen consumption rate and bile production. These changes were significantly suppressed in the mDsol-treated group. In the mDsol-D2O(-) and mDsol-DFX(-) groups offered partial protection. In conclusion, mDsol appeared to be superior to the UW solution for simple cold storage of the rat liver, presumably due to improved microcirculation in the early phase of reperfusion. Both heavy water and deferoxamine are essential for alleviating seamless organ swelling that occurs during cold storage and subsequent reperfusion.

Preservation Efficacy of a Quercetin and Sucrose Solution for Warm Ischemically Damaged Porcine Liver Grafts

The University of Wisconsin (UW) solution is the gold standard for preserving the liver, kidneys, and pancreas. For renal preservation, the addition of the flavonoid, quercetin (QE), to the preservation solution reduces damage to renal tubular cells, and the addition of sucrose (Suc) is also beneficial for preservation. The aim of this study was to investigate the protective effects of QE and Suc on porcine livers in terms of warm and cold injury and to evaluate whether their use improves ischemia-reperfusion (I/R) injury after simple cold storage (CS). We tested porcine livers procured after 30 minutes of warm ischemia followed by preservation for 6 hours under the following 2 conditions: group 1, preserved with the CS/UW solution (n=4); group 2, preserved with the CS/UW solution containing Que 33.1 μM and Suc 0.1 M (n=6). All livers were evaluated using an ex vivo isolated liver reperfusion model with saline-diluted autologous blood. Aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase levels in group 2 were significantly lower at 30 minutes of reperfusion than in group 1. Furthermore, histologic evaluation by hematoxylin and eosin staining showed significantly fewer morphologic changes in group 2 than in group 1, as indicated by the total Suzuki score. Group 2 also had significantly better scores for sinusoidal congestion and hepatocyte cytoplasmic vacuolization. Adding Que and Suc to the UW solution can effectively prevent cold injury in livers donated after circulatory death.

Beneficial effects of end-ischemic oxygenated machine perfusion preservation for split-liver transplantation in recovering graft function and reducing ischemia\u2013reperfusion injury

This study examined the efficacy of end-ischemic hypothermic oxygenated machine perfusion preservation (HOPE) using an originally developed machine perfusion system for split-liver transplantation. Porcine split-liver grafts were created via 75% liver resection after 10 min of warm ischemia. In Group 1, grafts were preserved by simple cold storage (CS) for 8 h (CS group; n = 4). In Group 2, grafts were preserved by simple CS for 6 h and end-ischemic HOPE for 2 h (HOPE group; n = 5). All grafts were evaluated using an isolated ex vivo reperfusion model with autologous blood for 2 h. Biochemical markers (aspartate aminotransferase and lactate dehydrogenase levels) were significantly better immediately after reperfusion in the HOPE group than in the CS group. Furthermore, the HOPE group had a better histological score. The levels of inflammatory cytokines (tumor necrosis factor-α, interferon-γ, interleukin-1β, and interleukin-10) were significantly lower after reperfusion in the HOPE group. Therefore, we concluded that end-ischemic HOPE for split-liver transplantation can aid in recovering the graft function and reducing ischemia–reperfusion injury. HOPE, using our originally developed machine perfusion system, is safe and can improve graft function while attenuating liver injury due to preservation.

Ischemic postconditioning improves the outcome of organs from donors after cardiac death in a pig liver transplantation model and provides synergistic protection with hypothermic machine perfusion.

This study investigated whether ischemic postconditioning (IPO) improved the outcome of organs from donors after cardiac death and had a synergistic effect with hypothermic machine perfusion (HMP) in a pig liver transplantation model. A donor after cardiac death (DCD) model was developed in 48 healthy Bama miniature pigs randomly divided into four groups: simple cold storage group (SCS group), IPO group, HMP group, HMP-IPO group. The levels of serum alanine aminotransferase (ALT), total bilirubin, histopathological findings, apoptotic activity of hepatocytes, international normalized ratio (INR), tumor necrosis factor-α (TNF-α), and Malondialdehyde (MDA) were compared. All recipients in the SCS group died within 6h after transplantation. The livers of the recipients in the IPO had 50% survival on day 5. HMP allowed 83.3% survival and HMP-IPO allowed 100% survival. After reperfusion, the recipients in the IPO and HMP-IPO group had lower ALT and total bilirubin levels, less Suzuki score, less apoptosis, and less injury to hepatocytes and biliary ducts and attenuated inflammatory response and oxidative load. IPO improved the outcome of organs from donors after cardiac death and had a synergistic effect with HMP in the pig liver transplantation model.

Use of the new preservation solution Custodiol-MP for ex vivo reconditioning of kidney grafts.

Organ shortage and the increasing use of extended criteria donor grafts for transplantation drives efforts for more efficient organ preservation strategies from simple cold storage toward dynamic organ reconditioning. The choice of a suitable preservation solution is of high relevance in different organ preservation or reconditioning situations. Custodiol-MP is a new machine perfusion solution giving the opportunity to add colloids according to organ requirements. The present study aimed to compare new Custodiol-MP with clinically established Belzer MPS solution. Porcine kidneys were ischemically predamaged and cold stored for 20 hours. Ex vivo machine reconditioning was performed either with Custodiol-MP (n = 6) or with Belzer MPS solution (n = 6) for 90 minutes with controlled oxygenated rewarming up to 20°C. Kidney function was evaluated using an established ex vivo reperfusion model. In this experimental setting, differences between both types of perfusion solutions could not be observed. Machine perfusion with Custodiol-MP resulted in higher creatinine clearance (7.4±8.6 mL/min vs. 2.8±2.5 mL/min) and less TNC perfusate levels (0.22±0.25 ng/mL vs. 0.09±0.08 ng/mL), although differences did not reach significance. For short-term kidney perfusion Custodiol-MP is safe and applicable. Particularly, the unique feature of flexible colloid supplementation makes the solution attractive in specific experimental and clinical settings.

Safety Monitoring System Design of Cold Storage Based on Single Chip Microcomputer

In order to solve the rising labor cost of cold storage management in China, and to improve the safety factor of cold storage, this paper designs a simple cold storage safety monitoring system. It is mainly to reflect the real-time monitoring information in the cold storage to the central background for unified processing, which not only reduces the harmful operations in the cold storage to save labor costs, but also improves the safety factor in the cold storage to reduce property losses. The monitoring system is fully automatic, which greatly reduces the staff’s effort in cold storage management.

Comparison of Continuous Hypothermic Oxygenated Crystalloid Perfusion with the Novel Solution “Custodiol N ” and Warm Blood Perfusion in a Porcine DCD Donation Model

Transplantation programs are worldwide burdened by the limited availability of suitable donor hearts, despite extending the donation criteria. Organ donation after circulatory death (DCD) became a reliable alternative over the past few years. Nevertheless, the grafts fetched as DCDs are submitted to a further ischemic insult due to the progressive hypoxia and circulatory arrest occurring between withdrawal of care and declaration of death. Although diverse storage and perfusion strategies exist to preserve DCD hearts, no direct comparison has yet been performed. The aim of the present study is to examine the effects of a novel cold crystalloid preservation solution (Custodiol-N) and warm blood perfusion protocols compared to simple cold storage in a porcine model. In 39 pigs, DCD was induced by asphyxia and the hearts underwent 30 min initial warm ischemia in the donor. The hearts were than explanted and divided in 4 groups: 1) control group (n=8) was placed directly in a Langendorff model. In group 2 (CSG, n=8) the hearts were flushed with 2L of 4°C Custodiol N solution and then stored in the same solution for 4h before evaluation. In group 3 (CCP, n=8), the hearts underwent a 4h continuous oxygenated 4°C cold machine perfusion cycle with Custodiol N. In group 4 (WBP, n=7) the hearts were placed on warm blood reperfusion for 4h. Left ventricular function was defined by dP/dt min & max at different ventricle filling volumes. Coronary blood flow (CBF) was measured at 100 mmHg perfusion pressure and Troponin T was collected up to 2 hours. Both dP/dt min & max were significantly higher in the CPP group compared to the WBP group [-1038±182 vs -344±38 mmHg/s; p=0.0356 and 1441±194 vs 498±53 mmHg/s; p=0.0123 respectively]. CBF was also significantly higher in the CCP group [1145±57vs 726±72ml/min; p=0.0032]. Moreover, Troponin T was significantly elevated in the WBP compared to the CCP group [27477±11777 vs 251034±90247 pg/ml, p=0.0239]. There were no significant differences among the WBP, CSG and control groups. Continuous hypothermic oxygenated crystalloid perfusion with the novel preservation solution Custodiol N offers superior preservation and resuscitation of DCD hearts in terms of functional recovery and myocardial enzyme release.

Applicability of Hypothermic Oxygenate Machine Perfusion Preservation for Split-Liver Transplantation in a Porcine Model: An Experimental Study.

BackgroundSplit-liver transplantation can be useful in situations of limited donor resources. However, novel preservation methods are required to help the recipient recover from severe ischemic reperfusion injury incurred due to receiving a relatively small liver graft.Material/MethodsOur experiment was performed using porcine livers without warm ischemia time, assuming a brain-dead organ. We made porcine split-liver grafts by 75% liver resection at the back table and divided the specimens into 4 groups. Group 1 was preserved with simple cold storage after splitting (CS; n=3), Group 2 was preserved with hypothermic perfusion preservation (HMP) after splitting (SBP; n=3), Group 3 was preserved with HMP after splitting under perfusion preservation (SDP; n=4), and Group 4 had the whole liver perfused as control grafts (Whole Liver; n=3). To assess potential methods of preservation and their effects, all grafts were evaluated by an ex vivo isolated liver reperfusion model using diluted autologous blood.ResultsPortal vein pressure resistances during reperfusion were low in Group3 (SDP). Hepatic artery pressure resistances during reperfusion were markedly higher in Group 1(CS) than in the other groups. The levels of AST and LDH were high and increased at 2 h after reperfusion in Group 1 (CS). The histological findings show that the liver cell structure was irregular in Group 1 (CS) but remained regular in Groups 2 (SBP) and 3 (SDP). Histological Suzuki scores were also significantly better in Groups 2 (SBP) and 3 (SDP) compared with Group 1 (CS).ConclusionsSplitting the liver under machine perfusion preservation may help restore the function and reduce ischemia-reperfusion injury.

Initial perfusate purification during subnormothermic machine perfusion for porcine liver donated after cardiac death.

Improvement of machine perfusion (MP) technologies is required to enhance organ quality for donor after cardiac death (DCD) grafts. Installing a dialyzer or a filter into the perfusion circuit to maintain the perfusate condition has some advantages. However, the consequences of purification perfusate during subnormothermic machine perfusion (SNMP) remain unexplained. In this study, the effects of initial purification perfusate with simple method of replacing the first 0.5-L perfusate during SNMP were investigated to consider installation effect of the filter or the dialyzer. Porcine liver grafts, which have 60-min warm ischemia time, were procured to imitate the DCD graft condition. Purified SNMP (PSNMP) results were compared with simple cold storage and conventional SNMP. In PSNMP, initial perfusate of 0.5L was removed to substitute for purification. After preservation process, the preserved grafts were reperfused with diluted autologous blood for 2h under normothermic machine perfusion condition to evaluate the liver function using an isolated reperfusion model. The vascular pressures, enzyme release rates and the metabolic indexes during reperfusion were analyzed. The pressures in the hepatic artery after reperfusion 60min were significantly lower in PSNMP group compared with cold storage (CS) and SNMP groups. In addition, lactate dehydrogenase and alkaline phosphatase were significantly lower after PSNMP than after the CS or SNMP. Also, the metabolic indexes of hyaluronic acid and lactate were significantly decreased by purifying the perfusate in MP preservation than in CS or SNMP. The effectiveness of initial purification perfusate during SNMP was investigated.

Modern concepts for the dynamic preservation of the liver and kidneys in the context of transplantation

The increasing demand on donor grafts has forced experimental research on transplantation medicine to develop more efficient organ preservation strategies. Simple cold storage of grafts rarely offers optimal conditions for extended criteria donor organs. Hypothermic, oxygenated machine perfusion (HMP) is aclassical method of dynamic organ preservation, which enables the provision of oxygen and nutrients to the tissue and provides ametabolic recovery of the graft prior to implantation. Amore modern approach is normothermic machine perfusion (NMP), which instead simulates physiological conditions and enables an ex vivo evaluation and treatment of organ grafts. However, studies have found that apreceding period of cold storage significantly mitigates the functional advantage of NMP. Astrategy to circumvent this phenomenon is controlled oxygenated rewarming (COR). The cold-stored graft is slowly and gradually rewarmed to subnormothermic or normothermic temperatures, providing agentle adaption of energy metabolism and counteracting events of rewarming injury.

Repeated Rhyolite Eruption From Heterogeneous Hot Zones Embedded Within a Cool, Shallow Magma Reservoir

AbstractDespite the hazard posed by explosive silicic eruptions, the magma storage conditions and dynamics that precede these events remain controversial. The Laguna del Maule volcanic field, central Chile, is an exceptional example of postglacial (younger than ca. 20,000 years) rhyolite volcanism and sustained unrest driven by a large, shallow, active silicic magma system. New zircon petrochronologic data reveal that compositionally distinct domains developed concurrently within the Laguna del Maule magma reservoir, which produced two episodes of concentrated rhyolitic eruptions at 23–19 and 8–2 ka. Zircon crystallization ages record 160 kyr of magma emplacement resulting in a several hundreds of cubic kilometers reservoir that has been imaged geophysically. The average magma emplacement rate inferred from the zircon geochronology and tomographically defined magma volume is consistent with those required by thermal models to maintain a shallow silicic system. Ti‐in‐zircon temperatures of crystal cores and rims and hiatuses in crystal growth indicates most of this volume persisted in a near‐solidus state. However, consistent patterns of trace element zoning in crystal interiors and crystallization rates derived from a model of diffusion‐limited zircon growth suggest the erupted rhyolite magma batches originated from long‐lived hot zones of extractable mush embedded within the larger, cool reservoir of rigid mush. These contrasting, coeval magma storage conditions obviate a simple hot versus cold storage dichotomy for large silicic magma systems.

Effect of the Selective NLRP3 Inflammasome Inhibitor mcc950 on Transplantation Outcome in a Pig Liver Transplantation Model With Organs From Donors After Circulatory Death Preserved by Hypothermic Machine Perfusion.

We investigated whether the outcome of organs from donors after circulatory death (DCD) can be improved by the addition of mcc950 to the perfusate of the hypothermic machine perfusion (HMP) system and intravenous mcc950 injection after transplantation in a pig liver transplantation model. Thirty-six healthy Bama mini pigs randomized into 3 groups. All the DCD livers were preserved in an HMP system after 2 hours of simple cold storage. In HMP-Postop group, mcc950 was added to the perfusate; in the control group and Postop group, the perfusate was normal LPS. After transplantation, the pigs in the Postop group and HMP-Postop group were intravenously administered 3 mg/kg mcc950, at the time of reperfusion and on day 2 and day 3 after transplantation. During the 3-day follow-up period, general operative characteristics, and serological markers and histological features related to ischemia reperfusion injury were examined. The HMP-Postop group suffer the lightest ischemia reperfusion injury (IRI), and functioned best after transplantation. Model for the Early Allograft Function Score (predictor of long-term survival), degree of injury in the hepatocytes and rate of apoptosis was lowest in the HMP-Postop group. Further, in the HMP-Postop group, the nucleotide-binding domain leucine-rich repeat containing family pyrin domain containing 3 inflammasome pathway activation was lowest, and the level of IL-1β was lowest. Postop group functioned better than control group, but not comparable with HMP-Postop group. The outcome of DCD organs can be improved by the addition of mcc950 to the perfusate of the HMP system and intravenous injection of mcc950 after transplantation.

Experience With Hypothermic Machine Perfusion in Expanded Criteria Donors: Functional Outcomes

Hypothermic machine perfusion (HMP) decreases delayed graft function (DGF) and improves 1-year graft survival in expanded criteria donors (ECDs). Time of HMP could be associated with incidence of DGF. ObjectiveTo analyze functional outcomes of ECD grafts preserved totally (local grafts) or partially (imported grafts) with HMP. Materials and MethodsWe analyzed prospectively collected data from a cohort of first ECD graft receptors, with a minimum follow-up of 6 months. A total of 119 imported and 74 local grafts were included. Local ECD kidneys were preserved with HMP after retrieval. Imported ECD kidneys were preserved with simple cold storage and HMP. Vascular thrombosis, acute rejection, DGF, 1-year glomerular filtration rate, and 1-year graft survival were assessed. Univariate and estimative multivariate logistic regression was applied for analysis of DGF. A Cox proportional hazards model was applied to estimate graft survival. ResultsDGF occurred in 14 recipients of local grafts and in 33 recipients of imported grafts (28.0 vs 18.1%, P = .13); 1-year graft survival was better in the group of local grafts (80.3 vs 91.9%, P = .03). No differences in vascular thrombosis (5.9 vs 5.4%, P = .88), acute rejection (12.3 vs 9.8%, P = .91), or 1-year glomerular filtration rate (41.2 vs 40.5 mL/m/1.73m2, P = .87) were observed. In multivariate analysis, adjusted odds ratio for DGF was 1.20 (P = .79) and adjusted hazard ratio for graft survival was 1.93 (P = .31). ConclusionsThere is a trend that complete HMP reduces the risk of DGF and improves 1-year graft survival in ECD kidneys.

Perfusion parameters during Hypothermic Machine Perfusion in Expanded Criteria Donors (ECD) and Donors after Circulatory Death (DCD). Does comparison allow their categorization?

Urology Surgery and Transplantation Group. IRYCIS. Introduction ECD represent up to 80% of kidney transplant (KT) activity at our Center, which has also received and accepted DCD imported grafts. HMP decreases the incidence of PNF and DGF, and increases 1-year graft survival compared to standard simple cold storage in ECD, moreover HMP decreases DGF in DCD. Flow and Renal Resistance (RR) during perfusion are used as graft viability parameters. The aim of the study was to compare donor and recipient characteristics as well as perfusion. Materials and Methods Study data were prospectively collected in a cohort of consecutive first KT recipients from ECD and imported type II and III DCD between February 2012 and September 2017 with a minimum 6 months follow-up. Local kidneys were placed on Life-Port in the donor operating room and delivered to the recipient on the pump. Kidneys imported from other organ procurement hospitals were initially placed on ice until reaching our center. Early graft loss, DGF, kidney function at 1 year post-KT and acute rejection were considered. Quantitative data were expressed as mean (SD) or median (IQA) and qualitative data as ratios. Comparison was conducted using Student t test; Mann-Whitney, Fischer or Chi squared as appropriate. Statistical significance was established at p<0.05. Results 230 recipients from ECD and 20 from DCD were included. DCD donors were significantly younger as expected (72.8 years vs 59.0 p= 0.00). There were no differences in respect to sex, final creatinine and main comorbidities except hypertension. Cold ischemia time was longer in ECD (17.5 hours vs 15.2; p= 0.045) although relative machine perfusion time were similar. Recipients from ECD were older and more frequently male but there were no differences in comorbidities and time in dialysis. Machine perfusion parameters didn´t show any difference at any time point, nevertheless flow and RI evolution through perfusion was as expected, with a significant increase in flow and corresponding decrease in RI (Table 1). Finally, DCD showed significantly more frequent DGF (47.4% vs 18.0%; p=0.001) and worse graft survival at 1 year (65.0% vs 83.3%; p=0,043). There were no differences in kidney function at 1 year in those functioning grafts (36.1 ml/min vs 40.7) (Table 2)..Conclusion DCD functional results were inferior to those obtained in ECD despite its HMP. Perfusion parameters (flow and resistance) had the usual behavior in both groups and didn`t allow to categorize their source. In the actual state of knowledge, results improvement in DCD KT involves an effort in decreasing and tight controlling cold ischemia time.

Efficacy of non-chlorine sanitizer, precooling and modified atmosphere packaging in improving shelf life of tomato during evaporative cooling and CoolBot cold storage

This study combined the use of non-chlorine sanitizer, precooling and modified atmosphere packaging (MAP) as prestorage treatments for tomato kept in a simple evaporative cooler (EC) or CoolBot cold storage (CS). Precooling was done by dipping the fruit in 10°C water until fruit temperature decreased to 13-15°C. As a non-chlorine sanitizing treatment, dipping fruit in 0.01% calcinated calcium (CCa) for 5 min at ambient temperature was used. For a combined precooling and sanitizing treatment, 10°C CCa solution was used. Tomatoes were stored in the EC or CS. Ambient storage was included for comparison. Fruits of a summer tomato cultivar, 'BARI Tomato-8', were used in this study. EC temperatures (24.3-27.5°C) were consistently lower and less fluctuating than ambient temperatures (27.8-31.0°C). The CoolBot temperature was maintained at 13±1°C. RH was about 75±2% in CS, whereas it was 75-95% under ambient conditions and 85-99% in the EC. Because of these conditions, together with the relatively high temperatures, fruit rotting was favored and limited the shelf life to 12-13 days, both under ambient conditions and in the EC. Fruit in the CS lasted for 18 days. Rotting affected ˃50% of the fruit on day 15 of ambient storage and of EC storage. In the CS, fruit rotting was first noted on day 9, increased gradually, and reached around 14-18% on day 18. Sanitizing treatment had little effect, but precooling had no extra benefits in reducing rot incidence. MAP significantly reduced weight loss in all storage conditions, showing a greater effect in the CS. Changes in fruit firmness and surface color were delayed significantly in CS compared with ambient conditions or EC storage. After 18 days of storage, the firmness of tomatoes remained higher when stored in CS, showing values of about 5.0 N. Vitamin C content was effectively maintained in the CS, and was about 12.6 mg 100 g-1 after 18 days of storage. EC- and ambient-stored fruit, on the other hand, had similar vitamin C contents at the end of their 12-day storage life.

An Oxygenated and Transportable Machine Perfusion System Fully Rescues Liver Grafts Exposed to Lethal Ischemic Damage in a Pig Model of DCD Liver Transplantation.

Control of warm ischemia (WI) lesions that occur with donation after circulatory death (DCD) would significantly increase the donor pool for liver transplantation. We aimed to determine whether a novel, oxygenated and hypothermic machine perfusion device (HMP Airdrive system) improves the quality of livers derived from DCDs using a large animal model. Cardiac arrest was induced in female large white pigs by intravenous injection of potassium chloride. After 60 minutes of WI, livers were flushed in situ with histidine-tryptophan-ketoglutarate and subsequently preserved either by simple cold storage (WI-SCS group) or HMP (WI-HMP group) using Belzer-MPS solution. Liver grafts procured from heart-beating donors and preserved by SCS served as controls. After 4 hours of preservation, all livers were transplanted. All recipients in WI-SCS group died within 6 hours after transplantation. In contrast, the HMP device fully protected the liver against lethal ischemia/reperfusion injury, allowing 100% survival rate. A postreperfusion syndrome was observed in all animals of the WI-SCS group but none of the control or WI-HMP groups. After reperfusion, HMP-preserved livers functioned better and showed less hepatocellular and endothelial cell injury, in agreement with better-preserved liver histology relative to WI-SCS group. In addition to improved energy metabolism, this protective effect was associated with an attenuation of inflammatory response, oxidative load, endoplasmic reticulum stress, mitochondrial damage, and apoptosis. This study demonstrates for the first time the efficacy of the HMP Airdrive system to protect liver grafts from lethal ischemic damage before transplantation in a clinically relevant DCD model.

Liver ex situ machine perfusion preservation: A review of the methodology and results of large animal studies and clinical trials.

Ex vivo machine perfusion (MP) is a promising way to better preserve livers prior to transplantation. Currently, no methodology has a verified benefit over simple cold storage. Before becoming clinically feasible, MP requires validation in models that reliably predict human performance. Such a model has been found in porcine liver, whose physiological, anatomical, and immunological characteristics closely resemble the human liver. Since the 1930s, researchers have explored MP as preservation, but only recently have clinical trials been performed. Making this technology clinically available holds the promise of expanding the donor pool through more effective preservation of extended criteria donor (ECD) livers. MP promises to decrease delayed graft function, primary nonfunction, and biliary strictures, which are all common failure modes of transplanted ECD livers. Although hypothermic machine perfusion (HMP) has become the standard for kidney ex vivo preservation, the precise settings and clinical role for liver MP have not yet been established. In research, there are 2 schools of thought: normothermic machine perfusion, closely mimicking physiologic conditions, and HMP, to maximize preservation. Here, we review the literature for porcine ex vivo MP, with an aim to summarize perfusion settings and outcomes pertinent to the clinical establishment of MP. Liver Transplantation 23 679-695 2017 AASLD.

Prediction, prevention, and management of delayed graft function: where are we now?

Delayed graft function (DGF) remains a major barrier to improved outcomes after kidney transplantation. High-risk transplant recipients can be identified, but no definitive prediction model exists. Novel biomarkers to predict DGF in the first hours post-transplant, such as neutrophil gelatinase-associated lipocalin (NGAL), are under investigation. Donor management to minimize the profound physiological consequences of brain death is highly complex. A hormonal resuscitation package to manage the catecholamine "storm" that follows brain death is recommended. Donor pretreatment with dopamine prior to procurement lowers the rate of DGF. Hypothermic machine perfusion may offer a significant reduction in the rate of DGF vs simple cold storage, but costs need to be evaluated. Surgically, reducing warm ischemia time may be advantageous. Research into recipient preconditioning options has so far not generated clinically helpful interventions. Diagnostic criteria for DGF vary, but requirement for dialysis and/or persistent high serum creatinine is likely to remain key to diagnosis until current work on early biomarkers has progressed further. Management centers on close monitoring of graft (non)function and physiological parameters. With so many unanswered questions, substantial reductions in the toll of DGF in the near future seem unlikely but concentrated research on many levels offers long-term promise.

Organ Preservation : Milestones and Basic Principles

Current shortage in organ donors led to the expansion of criteria for organ donation placing organ preservation as one cornerstone for successful transplant, graft function and survival. The historical work of Belzer and Collins paved the way for key descriptions of physiopathology of cell ischemia and protection (cytokines roles, oxidative stress, energy shift to lactic acidosis and perfusion pressure changes). Good preservation means immediate recovery of function and prevention of chronic rejection. Two cooling approaches are available: static (SCS: simple cold storage) suitable for all organs, and dynamic (HMP: hypothermic machines perfusion) designed for kidneys and liver. A thorough discussion of historically manufactured and widely sold preservation solutions e.g. EuroCollins, UW solution (Viaspan®) as well as current used solutions e.g. Custodiol® and the new Celsior is available in this review. Obviously, every single organ exhibits different tolerance to warm and cold ischemia depending on its nature and demands after transplant. Future perspectives of organ preservation may be hidden in hibernators which may hold the enigmas of perfect human organ preservation.

Rewarming Preservation by Organ Perfusion System for Donation After Cardiac Death Liver Grafts in Pigs

BackgroundUse of grafts from donors after cardiac death (DCD) would greatly contribute to the expansion of the donor organ pool. However, this requires the development of novel preservation methods to recover the organ from changes due to warm ischemia time (WIT). MethodsPorcine livers were perfused with a newly developed machine perfusion (MP) system. The livers were perfused with modified University of Wisconsin solution (UW) − gluconate. All grafts were procured after acute hemorrhagic shock with the ventilator off. For group 1 (n = 6), grafts were procured after WIT of 60 minutes and preserved by hypothermic MP (HMP) for 3 hours. For group 2 (n = 5), grafts were preserved with 2 hours of simple cold storage (SCS) and HMP for 2 hours. For group 3 (n = 6), grafts were preserved with 2 hours of SCS and rewarming up to 25°C by MP for 2 hours (RMP). The preserved liver grafts were transplanted orthotopically. ResultsThe alanine aminotransferase level in perfusate in RMP during perfusion preservation was maintained at less than that of HMP. The levels of aspartate aminotransferase and lactate dehydrogenase in the 2 hours after reperfusion were significantly lower in group 3. Histologically, the necrosis of hepatocytes was less severe in group 3. The survival rate in group 3 was 2/4, but 0/4 in the other group. ConclusionRMP is expected to facilitate the recovery of the DCD liver grafts.