Donation after cardio-circulatory death liver transplantation

Risk scores for allograft failure: Are they still useful in liver recipients from donation after circulatory death?

BACKGROUND

Liver grafts from donation after circulatory death (DCD) are associated with a higher risk of early graft dysfunction, determined by the warm ischemia and cold ischemia times. It is essential to have precise criteria to identify this complication in order to guide therapeutic strategies.

AIM

To validate different graft and recipient survival scores in patients undergoing liver transplantation (LT) with DCD grafts.

METHODS

A retrospective and observational unicentric study was conducted on 65 LT patients with grafts obtained from controlled DCD donors from November 2013 to November 2022. The United Kingdom (UK) risk score, early allograft dysfunction (EAD) Olthoff score, and model for early allograft function (MEAF) score were used to evaluate the risk of graft and recipient survival post-transplant. For survival analysis purposes, we used the Kaplan-Meier method, and the differences between subgroups were compared using the log-rank (Mantel-Cox) test.

RESULTS

Sixty-five patients were included in the study. The UK risk score did not demonstrate predictive capacity for recipient or graft survival. However, in donors aged over 70 years old (18.4%), it significantly predicted graft survival (P < 0.05). According to Kaplan-Meier survival curves, graft survival rates at 6 months, 2 years, and 5 years in the futility group dramatically decreased to 50% compared to the other groups (log-rank 8.806, P < 0.05). The EAD Olthoff and MEAF scores did not demonstrate predictive capacity for recipient or graft survival. Based on Kaplan-Meier survival curves, patients with a MEAF score ≥ 7 had a lower graft survival rate at 6 months, 2 years, and 5 years compared to patients with a lower MEAF score (log-rank 4.667, P < 0.05).

CONCLUSION

In our series, both UK DCD risk score and MEAF score showed predictive capability for graft survival.

Liver transplantation in Latin America: reality and challenges

Healthcare systems in Latin America are broadly heterogeneous, but all of them are burdened by a dramatic rise in liver disease. Some challenges that these countries face include an increase in patients requiring a transplant, insufficient rates of organ donation, delayed referral, and inequitable or suboptimal access to liver transplant programs and post-transplant care. This could be improved by expanding the donor pool through the implementation of education programs for citizens and referring physicians, as well as the inclusion of extended criteria donors, living donors and split liver transplantation. Addressing these shortcomings will require national shifts aimed at improving infrastructure, increasing awareness of organ donation, training medical personnel, and providing equitable access to care for all patients.

Uncontrolled donation after cardiac death kidney transplantation: Opportunity to expand the donor pool?

BACKGROUND

Compared to controlled donation after cardiac death (cDCD), uncontrolled DCD (uDCD) kidney transplantation remains an underutilized resource in the United States. However, it is unclear whether long-term allograft outcomes following uDCD are inferior to that of cDCD kidney transplantation.

METHODS

From January 1995 to January 2018, the OPTN/UNOS database was queried to discover all reported cases of uDCD and cDCD kidney transplantation. Primary non-function, delayed graft function, ten-year graft and patient survival were compared among uDCD and cDCD patients.

RESULTS

Rates of primary non-function (4.0% [uDCD] vs. 1.8% [cDCD], P < 0.001) and delayed graft function (51.1% [uDCD] vs. 41.7% [cDCD], P < 0.001) were higher following uDCD transplant. However, ten-year graft survival (47.5% [uDCD] vs. 48.4% [cDCD], P = 0.21) and patient survival were similar to cDCD transplantation (59.4% [uDCD] vs. 59.2% [cDCD], P = 0.32).

CONCLUSION

Although initial allograft outcomes are inferior following uDCD, long-term durability of uDCD kidney allografts is on par to cDCD transplantation. Kidney allografts derived by uDCD may be a viable and durable option to increase the donor pool.

Role of normothermic perfusion with ECMO in donation after controlled cardiac death in Spain

Spain has become one of the most active countries in donation after controlled cardiac death, using normothermic abdominal perfusion with ECMO in more than 50% of all donors - a situation contributed to by the creation of mobile teams to support hospitals lacking this technology. The donation process must be respectful of the wishes and values of the patients and their relatives, especially if there is pre mortem manipulation, and the absence of cerebral perfusion should be guaranteed. The liver is the most benefited organ by reducing biliary complications as well as the loss of grafts. In renal transplantation, the technique could contribute to reduce the incidence of delayed graft function. In addition, the procedure is compatible with surgical rapid recovery in hypothermia when there is also lung donation. The future lies in the consolidation of cardiac donation by extending normothermic perfusion to the thoracic cavity.

Long-Term Outcomes of Early Experience in Donation After Circulatory Death Liver Transplantation: Outcomes at 10 Years

BACKGROUND Donation after circulatory death (DCD) livers remain an underutilized pool of transplantable organs due to concerns of inferior long-term patient survival (PS) and graft survival (GS), which factors greatly into clinician decision-making and patient expectations. MATERIAL AND METHODS This retrospective study used SRTR data to assess 33 429 deceased-donor liver transplants (LT) and compared outcomes between DCD and donation after brain death (DBD) LT recipients in the United States. Data were collected from 2002 to 2008 to obtain 10 years of follow-up (2012-2018) in the era of MELD implementation. Propensity scores for donor type (DCD vs DBD) were estimated using logistic regression, and the association of donor type with 10-year outcomes was evaluated after adjustment using stabilized inverse probability of treatment weights. RESULTS After adjusting for confounders, patient survival for DBD recipients at 10 years was 60.7% versus 57.5% for DCD recipients (P=0.24). Incorporating retransplants, 10-year adjusted patient survival was 60.2% for DBD recipients versus 55.5% for DCD recipients (P=0.07). Adjusted 10-year graft survival for DBD recipients was 56.4% versus 45.4% for DCD recipients (P<0.001). Surprisingly, however, 1 year after LT, DBD and DCD graft failure rates converged to 7.5% over the remaining 9 years. CONCLUSIONS These data reveal inferior 10-year DCD graft survival, but only in the first year after LT, and similar 10-year patient survival in DCD LT recipients compared to DBD recipients. Our results show the stability and longevity of DCD grafts, which should encourage the increased utilization of these livers for transplantation.

Evolving utilization of donation after circulatory death livers in liver transplantation: The day of DCD has come

Compared to donation after brain death (DBD), livers procured for transplantation from donation after circulatory death (DCD) donors experience more ischemia-reperfusion injury and higher rates of ischemic cholangiopathy due to the period of warm ischemic time (WIT) following withdrawal of life support. As a result, utilization of DCD livers for liver transplant (LT) has generally been limited to short WITs and younger aged donor grafts, causing many recovered DCD organs to be discarded without consideration for transplant. This study assesses how DCD liver utilization and outcomes have changed over time, using OPTN data from adult, first-time, deceased donor, whole-organ LTs between January 1995 and December 2019. Results show that increased clinical experience with DCD LT has translated into increased use of livers from DCD donors, shorter ischemic times, shorter lengths of hospitalization after transplant, and lower rates of retransplantation. The data also reveal that over the past decade, the rate of increase in DCD LTs conducted in the United States has outpaced that of DBD. Together, these trends signal an opportunity for the field of liver transplantation to mitigate the organ shortage by capitalizing on DCD liver allografts that are currently not being utilized.

Hepatocyte-derived MANF alleviates hepatic ischaemia-reperfusion injury via regulating endoplasmic reticulum stress-induced apoptosis in mice

BACKGROUND

Endoplasmic reticulum (ER) perturbations are novel subcellular effectors involved in the ischaemia-reperfusion injury. As an ER stress-inducible protein, mesencephalic astrocyte-derived neurotrophic factor (MANF) has been proven to be increased during ischaemic brain injury. However, the role of MANF in liver ischaemia reperfusion (I/R) injury has not yet been studied.

METHODS

To investigate the role of MANF in the process of liver ischaemia-reperfusion, Hepatocyte-specific MANF knockout (MANF^hep-/- ) mice and their wild-type (WT) littermates were used in our research. Mice partial (70%) warm hepatic I/R model was established by vascular occlusion. We detected the serum levels of MANF in both liver transplant patients and WT mice before and after liver I/R injury. Recombinant human MANF (rhMANF) was injected into the tail vein before 1 hour occlusion. AST, ALT and Suzuki score were used to evaluate the extent of I/R injury. OGD/R test was performed on primary hepatocytes to simulate IRI in vitro. RNA sequence and RT-PCR were used to detect the cellular signal pathway activation while MANF knockout.

RESULTS

We found that MANF expression and secretion are dramatically up-regulated during hepatic I/R. Hepatocyte-specific MANF knockout aggravates the I/R injury through the over-activated ER stress. The systemic administration of rhMANF before ischaemia has the potential to ameliorate I/R-triggered UPR and liver injury. Further study showed that MANF deficiency activated ATF4/CHOP and JNK/c-JUN/CHOP pathways, and rhMANF inhibited the activation of the two proapoptotic pathways caused by MANF deletion.

CONCLUSION

Collectively, our study unravels a previously unknown relationship among MANF, UPR and hepatic I/R injury.

Evaluation of Liver Quality after Circulatory Death Versus Brain Death: A Comparative Preclinical Pig Model Study

The current organ shortage in hepatic transplantation leads to increased use of marginal livers. New organ sources are needed, and deceased after circulatory death (DCD) donors present an interesting possibility. However, many unknown remains on these donors and their pathophysiology regarding ischemia reperfusion injury (IRI). Our hypothesis was that DCD combined with abdominal normothermic regional recirculation (ANOR) is not inferior to deceased after brain death (DBD) donors. We performed a mechanistic comparison between livers from DBD and DCD donors in a highly reproducible pig model, closely mimicking donor conditions encountered in the clinic. DCD donors were conditioned by ANOR. We determined that from the start of storage, pro-lesion pathways such as oxidative stress and cell death were induced in both donor types, but to a higher extent in DBD organs. Furthermore, pro-survival pathways, such as resistance to hypoxia and regeneration showed activation levels closer to healthy livers in DCD-ANOR rather than in DBD organs. These data highlight critical differences between DBD and DCD-ANOR livers, with an apparent superiority of DCD in terms of quality. This confirms our hypothesis and further confirms previously demonstrated benefits of ANOR. This encourages the expended use of DCD organs, particularly with ANOR preconditioning.

Successful clinical transplantation of hearts donated after circulatory death using normothermic regional perfusion

BACKGROUND

Heart transplantation (HT) from donation after circulatory death (DCD) has yet to achieve wide clinical application despite the encouraging resultsreported recently. In this study we describe 2 cases of successful adult DCD HT performed at our institution using an original protocol.

METHODS

Our local abdominal DCD protocol was updated to allow DCD heart procurement, and was accepted by the institutional ethics committee. The main features of the protocol include: pre-mortem insertion of peripheral venoarterial extracorporeal membrane oxygenation cannulas; thoracoabdominal normothermic regional perfusion (NRP) by clamping the 3 aortic arch vessels to exclude cerebral circulation; and in-situ heart resuscitation. The retrieved hearts were directly transplanted into recipients located in an adjoining operating room.

RESULTS

The procurement warm ischemic time was 25 minutes for the first donor, and 26 minutes for the second donor. The cold ischemic time was 16 minutes for the first recipient and 17 minutes for the second recipient. The suture time was 30 minutes for the first recipient, and 53 minutes for the second recipient. Both recipients were easily weaned off cardiopulmonary bypass in sinus rhythm and inotropic support. Post-operative evaluation of cardiac function was excellent and the patients were subsequently discharged home.

CONCLUSIONS

Transplantation of hearts from DCD donors is now a clinical reality.NRP is a useful tool for resuscitation, reperfusion, and preservation of transplanted hearts. It also offers the opportunity to assess the function and viability of organs before transplantation. However,due to ethical issues, some may object to ante-mortem intervention.

A 'real-world' analysis of risk factors for post liver transplant delirium and the effect on length of stay

BACKGROUND

The development of delirium has been previously demonstrated to be associated with an increased risk of mortality and length of stay post liver transplant (LTx) with multiple risk factors being identified in previous studies. In this study, we have aimed to identify the most important variables associated with the onset of post-LTx delirium and understand the effect on length of stay (LOS).

METHODS

All liver transplants for chronic liver disease between 1 August 2012 and 1 August 2017 were included (n = 793). Data were collected for analysis retrospectively from electronic patient records.

RESULTS

Delirium is associated with an overall increased hospital and ICU LOS but not one-year mortality. The risk of developing post-LTx delirium was the greatest among patients: with post-LTx sepsis, who required renal sparing immunosuppression, who received donation after cardiac death (DCD) grafts and who were older. Patients with autoimmune hepatitis, primary biliary cholangitis or primary sclerosing cholangitis seemed to be at lower risk of post-LTx delirium. However, global patient LOS was only prolonged in patients with sepsis and renal failure.

CONCLUSION

Many of the risk factors previously described to be associated with the development of post-LTx delirium were not demonstrated to be significant in this study. Sepsis, renal failure, older age and DCD use are associated with delirium post-LTx. It is unclear if this syndrome is an independent risk factor for increased LOS or if it is a symptom of well established syndromes associated with increased LOS. The role for prophylactic strategies to reduce the incidence of post-LTx delirium is therefore unclear.

Adenosine A2a Receptor Stimulation Attenuates Ischemia-Reperfusion Injury and Improves Survival in A Porcine Model of DCD Liver Transplantation

Orthotopic liver transplantation (OLT) using allografts from donation after circulatory death (DCD) is potentially associated with compromised clinical outcomes due to ischemia-reperfusion injury (IRI)-induced organ damage and graft-related complications. The aim of this study was to provide in vivo data on the effects of adenosine A2a receptor stimulation in a clinically relevant large animal model of DCD liver transplantation. Cardiac arrest was induced in German Landrace pigs (n = 10; 20-25 kg). After 30 min of warm ischemia, the donor liver was retrieved following a cold flush with 3 L of histidine-tryptophan-ketoglutarate-HTK solution. Animals of the treatment group (n = 5/group) received a standard dose of the selective adenosine receptor agonist CGS 21680 added to the cold flush. All grafts were stored for 4.5 h at 4 °C in HTK-solution before OLT. Hepatocellular injury, apoptosis, protein kinase A-PKA activity, graft microcirculation, liver function, and animal survival were assessed. Compared to untreated livers, adenosine A2a receptor stimulation resulted in improved tissue microcirculation (103% ± 5% vs. 38% ± 4% compared to baseline; p < 0.05), accelerated functional recovery of the graft (indocyanine green-plasma disappearance rate (ICG-PDR) of 75% ± 18% vs. 40% ± 30% after 3 h), increased PKA activity ratio (56% ± 3% vs. 32% ± 3%; p < 0.001 after 1 h), and consequently reduced tissue necrosis and apoptosis. The potent protective effects were clinically manifested in significantly improved survival in the treatment group after 72 h (100% vs. 40%; p = 0.04). The ex vivo administration of adenosine A2a receptor agonist during the back-table flush mitigates IRI-mediated tissue damage and improves functional graft recovery and survival in a large animal model of DCD liver transplantation.

Role of normothermic perfusión with ECMO in donation after controlled cardiac death in Spain

Spain has become one of the most active countries in donation after controlled cardiac death, using normothermic abdominal perfusion with ECMO in more than 50% of all donors - a situation contributed to by the creation of mobile teams to support hospitals lacking this technology. The donation process must be respectful of the wishes and values of the patients and their relatives, especially if there is pre mortem manipulation, and the absence of cerebral perfusion should be guaranteed. The liver is the most benefited organ by reducing biliary complications as well as the loss of grafts. In renal transplantation, the technique could contribute to reduce the incidence of delayed graft function. In addition, the procedure is compatible with surgical rapid recovery in hypothermia when there is also lung donation. The future lies in the consolidation of cardiac donation by extending normothermic perfusion to the thoracic cavity.

Controlled donation after circulatory death up to 80 years for liver transplantation: Pushing the limit again

Our main objective was to compare liver transplant (LT) results between donation after circulatory death (DCD) and donation after brainstem death (DBD) in our hospital and to analyze, within the DCD group, the influence of age on the results obtained with DCD donors aged >70 years and up to 80 years. All DCD-LTs performed were analyzed prospectively. The results of the DCD group were compared with those of a control group who received a DBD-LT immediately after each DCD-LT. Later, the results obtained within the DCD group were analyzed according to the age of the donors, considering 2 subgroups with a cut-off point at 70 years. Survival results for LT with DCD and super rapid recovery were not inferior to those obtained in a similar group of patients transplanted with DBD livers. However, the cost of DCD was a higher rate of biliary complications, including ischemic cholangiopathy. Donor age was not a negative factor.

Impact of human-derived hemoglobin based oxygen vesicles as a machine perfusion solution for liver donation after cardiac death in a pig model

The recent clinical application of perfusion technology for the machine preservation of donation after cardiac death (DCD) grafts has some advantages. Oxygenation has been proposed for the preservation of DCD liver grafts. The aim of this study is to clarify whether the use of HbV-containing preservation solution during the subnormothermic machine perfusion (SNMP) of the liver graft improves the graft function of DCD porcine livers in an ex vivo reperfusion model. Pig livers were excised after 60 minutes of warm ischemic time and were preserved under one of three preservation conditions for 4 hours. The preservation conditions were as follows: 4°C cold storage (CS group; N = 5), Hypothermic machine preservation (HMP) with UW gluconate solution (HMP group; N = 5), SNMP (21°C) with UW gluconate solution (SNMP group; N = 5), SNMP (21°C) with HbVs (Hb; 1.8 mg/dl) perfusate (SNMP+HbV group; N = 5). Autologous blood perfusion was performed for 2 hours in an isolated liver reperfusion model (IRM). The oxygen consumption of the SNMP and SNMP+HbV group was higher than the HMP groups (p < 0.05). During the reperfusion, the AST level in the SNMP+HbV group was lower than that in the CS, HMP and SNMP groups. The changes in pH after reperfusion was significantly lower in SNMP+HbV group than CS and HMP groups. The ultrastructural findings indicated that the mitochondria of the SNMP+HbV group was well maintained in comparison to the CS, HMP and SNMP groups. The SNMP+HbVs preservation solution protected against metabolic acidosis and preserved the liver function after reperfusion injury in the DCD liver.

Systematic Review: Clinical Metabolomics to Forecast Outcomes in Liver Transplantation Surgery

Liver transplantation is an effective intervention for end-stage liver disease, fulminant hepatic failure, and early hepatocellular carcinoma. Yet, there is marked patient-to-patient variation in liver transplantation outcomes. This calls for novel diagnostics to enable rational deployment of donor livers. Metabolomics is a postgenomic high-throughput systems biology approach to diagnostic innovation in clinical medicine. We report here an original systematic review of the metabolomic studies that have identified putative biomarkers in the context of liver transplantation. Eighteen studies met the inclusion criteria that involved sampling of blood (n = 4), dialysate fluid (n = 4), bile (n = 5), and liver tissue (n = 5). Metabolites of amino acid and nitrogen metabolism, anaerobic glycolysis, lipid breakdown products, and bile acid metabolism were significantly different in transplanted livers with and without graft dysfunction. However, criteria for defining the graft dysfunction varied across studies. This systematic review demonstrates that metabolomics can be deployed in identification of metabolic indicators of graft dysfunction with a view to implicated molecular mechanisms. We conclude the article with a horizon scanning of metabolomics technology in liver transplantation and its future prospects and challenges in research and clinical practice.

The dawn of liver perfusion machines

PURPOSE OF REVIEW

Despite high demand, a severe shortage of suitable allografts limits the use of liver transplantation for the treatment of end-stage liver disease. The transplant community is turning to the utilization of high-risk grafts to fill the void. This review summarizes the reemergence of ex-vivo machine perfusion for liver graft preservation, including results of recent clinical trials and its specific role for reconditioning DCD, steatotic and elderly grafts.

RECENT FINDINGS

Several phase-1 clinical trials demonstrate the safety and feasibility of machine perfusion for liver graft preservation. Machine perfusion has several advantages compared with static cold storage and may provide superior transplantation outcomes, particularly for marginal grafts. Ongoing multicenter trials aim to confirm the results of preclinical and pilot studies and establish the clinical utility of ex-vivo liver machine perfusion.

SUMMARY

Mounting evidence supports the benefits of machine perfusion for preservation of liver grafts. Thus, machine perfusion is a promising strategy to expand the donor pool by reconditioning and assessing viability of DCD, elderly and steatotic grafts during the preservation period. Additionally, machine perfusion will serve as a platform to facilitate graft intervention and modification to further optimize marginal grafts.

Normothermic ex-vivo liver perfusion: where do we stand and where to reach?

Nowadays liver transplantation is considered as the treatment of choice, however, the scarcity of suitable donor organs limits the delivery of care to the end-stage liver disease patients leading to the death while on the waiting list. The advent of ex-situ normothermic machine perfusion (NMP) has emerged as an alternative to the standard organ preservation technique, static cold storage (SCS). The newer technique promises to not only restore the normal metabolic activity but also attempt to recondition the marginal livers back to the pristine state, which are otherwise more susceptible to ischemic injury and foster the poor post-transplant outcomes. Areas covered: An extensive search of all the published literature describing the role of NMP based device in liver transplantation as an alternative to SCS was made on MEDLINE, EMBASE, Cochrane, BIOSIS, Crossref, Scopus databases and clinical trial registry on 10 May 2018. Expert commentary: The main tenet of NMP is the establishment of the physiological milieu, which permits aerobic metabolism to continue through out the period of preservation and limits the effects of ischemia-reperfusion (I/R) injury. In addition, by assessing the various metabolic and synthetic parameters the viability and suitability of donor livers for transplantation can be determined. This important technological advancement has scored satisfactorily on the safety and efficacy parameters in preliminary clinical studies. The present review suggests that NMP can offer the opportunity to assess and safely utilize the marginal donor livers if deemed appropriate for the transplantation. However, ongoing trials will determine its full potential and further adoption.

Hypothermic oxygenated perfusion (HOPE) attenuates ischemia/reperfusion injury in the liver through inhibition of the TXNIP/NLRP3 inflammasome pathway in a rat model of donation after cardiac death

Hypothermic oxygenated perfusion (HOPE) is a relatively new dynamic preservation procedure that has not been widely implemented in liver transplantation despite its advantages. Improved graft protection is one such advantage offered by HOPE and has been attributed to multiple mechanisms, one of which may be the modulation of the thioredoxin-interacting protein (TXNIP)/NOD-like receptor protein 3 (NLRP3) inflammasome pathway. The TXNIP/NLRP3 inflammasome pathway plays a critical role in sterile inflammation under oxidative stress as a result of ischemia/reperfusion injury (IRI). In the current study, we aimed to investigate the graft protection offered by HOPE and its impact on the TXNIP/NLRP3 inflammasome pathway. To simulate conditions of donation after cardiac death (DCD) liver transplantation, rat livers were exposed to 30 min of warm ischemia after cardiac arrest. Livers were then preserved under cold storage (CS) or with HOPE for 3 h. Livers were then subjected to 1 h of isolated reperfusion. Liver injuries were assessed on the isolated perfusion rat liver model system before and after reperfusion. Compared with the CS group, the HOPE group had a significant reduction in liver injury and improvement in liver function. Our findings also revealed that reperfusion injury induced liver damage and activated the TXNIP/NLRP3 inflammasome pathway in DCD rat livers. Pretreatment of DCD rat livers with HOPE inhibited the TXNIP/NLRP3 inflammasome pathway and attenuated liver IRI. Attenuation of oxidative stress as a result of HOPE led to the down-regulation of the TXNIP/NLRP3 inflammasome pathway and thus offered superior protection compared with the traditional CS method of organ preservation.-He, W., Ye, S., Zeng, C., Xue, S., Hu, X., Zhang, X., Gao, S., Xiong, Y., He, X., Vivalda, S., Li, L., Wang, Y., Ye, Q. Hypothermic oxygenated perfusion (HOPE) attenuates ischemia/reperfusion injury in the liver through inhibition of the TXNIP/NLRP3 inflammasome pathway in a rat model of donation after cardiac death.

Hepatocellular uptake of cyclodextrin-complexed curcumin during liver preservation: A feasibility study

The increasing demand for donor organs and the decreasing organ quality is prompting research toward new methods to reduce ischemia reperfusion injury (IRI). Several strategies have been proposed to protect preserved organs from this injury. Before curcumin/dextrin complex (CDC), a potent antioxidant and anti-inflammatory agent, can be used clinically we need to better understand the intracellular uptake under hypothermic conditions on a rat model of liver donation after circulatory death (DCD) and brain death (DBD). To be able to use the fluorescence of CDC for quantification the stability of CDC in different preservation solutions at 4°C or 37°C was investigated. Livers from Wistar rats were procured after being flushed-out through the portal vein using CDC-enriched preservation solutions and stored at 4°C for variable periods. The CDC signal was stable in different preservation solutions over a period of 4 h and allowed the rapid and lasting uptake of curcumin into cells. After 4 h of preservation, CDC was no longer visible microscopically, and HPLC analysis showed very low to non-detectable tissue levels of CDC, proving metabolization during preservation. However, the distribution of CDC was not affected by warm ischemia damage (p = 0.278) nor by flushing the livers before or after 4 h of cold storage and without a warm preflush. Finally, curcumin reduced oxidative stress, lowered histological injury and did not change gene expression after WI/cold storage. Therefore, the use of CDC flush solution for the initial organ flush can offer a promising approach to the enhancement of liver preservation and the maintenance of its quality.

Donation After Circulatory Death for Liver Transplantation: A Meta-Analysis on the Location of Life Support Withdrawal Affecting Outcomes

BACKGROUND

Liver transplantation using donation after circulatory death (DCD) donors is associated with inferior outcomes compared to donation after brain death (DBD). Prolonged donor warm ischemic time has been identified as the key factor responsible for this difference. Various aspects of the donor life support withdrawal procedure, including location of withdrawal and administration of antemortem heparin, are thought to play important roles in mitigating the effects of warm ischemia. However, a systematic exploration of these factors is important for more confident integration of these practices into a standard DCD protocol.

METHODS

Medline, EMBASE, and Cochrane libraries were systematically searched and 23 relevant studies identified for analysis. Donation after circulatory death recipients were stratified according to location of life support withdrawal (intensive care unit or operating theater) and use of antemortem heparin.

RESULTS

Donation after circulatory death recipients had comparable 1-year patient survival to DBD recipients if the location of withdrawal of life support was the operating theater, but not if the location was the intensive care unit. Likewise, the inferior 1-year graft survival and higher incidence of ischemic cholangiopathy of DCD compared with DBD recipients were improved by withdrawal in operating theater, although higher rates of ischemic cholangiopathy and worse graft survival were still observed in DCD recipients. Furthermore, administering heparin before withdrawal of life support reduced the incidence of primary nonfunction of the allograft.

CONCLUSIONS

Our evidence suggests that withdrawal in the operating theater and premortem heparin administration improve DCD liver transplant outcomes, thus allowing for the most effective usage of these valuable organs.

Current challenges and future directions for liver transplantation

Liver transplantation is an effective and widely used therapy for several patients with acute and chronic liver diseases. The discrepancy between the number of patients on the waiting list and available donors remains the key issue and is responsible for the high rate of waiting list mortality. The recent news is that the majority of patients with hepatitis C virus related liver disease will be cured by new antivirals therefore we should expect soon a reduction in the need of liver transplantation for these recipients. This review aims to highlight, in two different sections, the main open issues of liver transplantation concerning the current and future strategies to the best use of limited number of organs. The first section cover the strategies to increase the donor pool, discussing the use of older donors, split grafts, living donation and donation after cardiac death and mechanical perfusion systems to improve the preservation of organs before liver transplantation. Challenges in immunosuppressive therapy and operational tolerance induction will be evaluated as potential tools to increase the survival in liver transplant recipients and to reducing the need of re-transplantation. The second section is devoted to the evaluation of possible new indications to liver transplantation, where the availability of organs by implementing the strategies mentioned in the first section and the reduction in the number of waiting transplants for HCV disease is realized. Among these new potential indications for transplantation, the expansion of the Milan criteria for hepatocellular cancer is certainly the most open to question.

[Non-heart-beating donors are ineligible]

The death of the donor is a mandatory prerequisite for organ transplantation (dead donor rule) worldwide. It is a medical, legal and ethical consensus to accept the concept of brain death, as first proposed in 1968 by the ad hoc committee of the Harvard Medical School, as a certain criterion of death. In isolated cases where the diagnosis of brain death was claimed to be wrong, it could be demonstrated that the diagnostic procedure for brain death had not been correctly performed. In March 2014 a joint statement by the German neuromedical societies emphasized that 1) the diagnosis of brain death is one of the safest diagnoses in medicine if performed according to accepted medical standards and criteria and 2) the concept of non-heart-beating donors (NHBD, i. e. organ donation after an arbitrarily defined duration of circulatory and cardiac arrest) practiced in some European countries must be absolutely rejected because it implicates a high risk of diagnostic error. According to the current literature it is unclear at what time cardiac and circulatory arrest is irreversible and leads to irreversible cessation of all functions of the entire brain including the brainstem, even though clinical signs of cessation of brain functions are always found after 10 min. Furthermore, is it often an arbitrary decision to exactly define the duration of cardiac arrest if continuous echocardiographic monitoring has not been carried out from the very beginning. Last but not least there are ethical concerns against the concept of NHBD because it might influence therapeutic efforts to resuscitate a patient with cardiac arrest. Therefore, the German Medical Council (BÄK) has repeatedly rejected the concept of NHBD for organ transplantation since 1995.

TAK-242 treatment ameliorates liver ischemia/reperfusion injury by inhibiting TLR4 signaling pathway in a swine model of Maastricht-category-III cardiac death

OBJECTIVES

This study aims to test the effects of TAK-242 on liver transplant viability in a model of swine Maastricht-category-III cardiac death.

METHODS

A swine DCD Maastricht-III model of cardiac death was established, and TAK-242 was administered prior to the induction of cardiac death. The protein and mRNA level of TLR4 signaling pathway molecules and cytokines that are important in mediating immune and inflammatory responses were assessed at different time points following the induction of cardiac death.

RESULTS

After induction of cardiac death, both the mRNA and protein levels of key molecules (TLR4, TRAF6, NF-ϰB, ICAM-1, MCP-1 and MPO), TNF-α and IL-6 increased significantly. Infusion of TAK-242 1h before induction of cardiac death blocked the increase of immune and inflammatory response molecules. However, the increase of TLR4 level was not affected by infusion of TAK-242. Histology study showed that infusion of TAK-242 protect liver tissue from damage during cardiac death.

CONCLUSIONS

These results indicates that TLR4 signaling pathway may contribute to ischemia/reperfusion injury in the liver grafts, and blocking TLR4 pathway with TAk-242 may reduce TLR4-mediated tissue damage.

Extended-criteria donors in liver transplantation Part II: reviewing the impact of extended-criteria donors on the complications and outcomes of liver transplantation

Extended-criteria donors (ECDs) have an impact on early allograft dysfunction (EAD), biliary complications, relapse of hepatitis C virus (HCV), and survivals. Early allograft dysfunction was frequently seen in grafts with moderate and severe steatosis. Donors after cardiac death (DCD) have been associated with higher rates of graft failure and biliary complications compared to donors after brain death. Extended warm ischemia, reperfusion injury and endothelial activation trigger a cascade, leading to microvascular thrombosis, resulting in biliary necrosis, cholangitis, and graft failure. The risk of HCV recurrence increased by donor age, and associated with using moderately and severely steatotic grafts. With the administration of protease inhibitors sustained virological response was achieved in majority of the patients. Donor risk index and EC donor scores (DS) are reported to be useful, to assess the outcome. The 1-year survival rates were 87% and 40% respectively, for donors with a DS of 0 and 3. Graft survival was excellent up to a DS of 2, however a DS >2 should be avoided in higher-risk recipients. The 1, 3 and 5-year survival of DCD recipients was comparable to optimal donors. However ECDs had minor survival means of 85%, 78.6%, and 72.3%. The graft survival of split liver transplantation (SLT) was comparable to that of whole liver orthotopic liver transplantation. SLT was not regarded as an ECD factor in the MELD era any more. Full-right-full-left split liver transplantation has a significant advantage to extend the high quality donor pool. Hypothermic oxygenated machine perfusion can be applied clinically in DCD liver grafts. Feasibility and safety were confirmed. Reperfusion injury was also rare in machine perfused DCD livers.

Incidence and risk factors for early renal dysfunction after liver transplantation

AIM: To determine renal dysfunction post liver transplantation, its incidence and risk factors in patients from a Belgian University Hospital.

METHODS: Orthotopic liver transplantations performed from January 2006 until September 2012 were retrospectively reviewed (n = 187). Patients with no renal replacement therapy (RRT) before transplantation were classified into four groups according to their highest creatinine plasma level during the first postoperative week. The first group had a peak creatinine level below 12 mg/L, the second group between 12 and 20 mg/L, the third group between 20 and 35 mg/L, and the fourth above 35 mg/L. In addition, patients who needed RRT during the first week after transplantation were also classified into the fourth group. Perioperative parameters were recorded as risk factors, namely age, sex, body mass index (BMI), length of preoperative hospital stay, prior bacterial infection within one month, preoperative ascites, preoperative treatment with β-blocker, angiotensin-converting enzyme inhibitor or non steroidal anti-inflammatory drugs, preoperative creatinine and bilirubin levels, donor status (cardiac death or brain death), postoperative lactate level, need for intraoperative vasopressive drugs, surgical revision, mechanical ventilation for more than 24 h, postoperative bilirubin and transaminase peak levels, postoperative hemoglobin level, amount of perioperative blood transfusions and type of immunosuppression. Univariate and multivariate analysis were performed using logistic ordinal regression method. Post hoc analysis of the hemostatic agent used was also done.

RESULTS: There were 78 patients in group 1 (41.7%), 46 in group 2 (24.6%), 38 in group 3 (20.3%) and 25 in group 4 (13.4%). Twenty patients required RRT: 13 (7%) during the first week after transplantation. Using univariate analysis, the severity of renal dysfunction was correlated with presence of ascites and prior bacterial infection, preoperative bilirubin, urea and creatinine level, need for surgical revision, use of vasopressor, postoperative mechanical ventilation, postoperative bilirubin and urea, aspartate aminotransferase (ASAT), and hemoglobin levels and the need for transfusion. The multivariate analysis showed that BMI (OR = 1.1, P = 0.004), preoperative creatinine level (OR = 11.1, P < 0.0001), use of vasopressor (OR = 3.31, P = 0.0002), maximal postoperative bilirubin level (OR = 1.44, P = 0.044) and minimal postoperative hemoglobin level (OR = 0.059, P = 0.0005) were independent predictors of early post-liver transplantation renal dysfunction. Neither donor status nor ASAT levels had significant impact on early postoperative renal dysfunction in multivariate analysis. Absence of renal dysfunction (group 1) was also predicted by the intraoperative hemostatic agent used, independently of the extent of bleeding and of the preoperative creatinine level.

CONCLUSION: More than half of receivers experienced some degree of early renal dysfunction after liver transplantation. Main predictors were preoperative renal dysfunction, postoperative anemia and vasopressor requirement.

Early occurrence of new-onset diabetes after transplantation is related to type of liver graft and warm ischaemic injury

BACKGROUND & AIMS

We studied new-onset diabetes after transplantation (NODAT) in liver transplantation with grafts donated after brain death (DBD) or circulatory death (DCD), focusing on the early post-transplant period.

METHODS

A total of 430 non-diabetic primary liver transplant recipients [DCD, n = 90 (21%)] were followed up for 30 months (range 5-69). NODAT was defined as the composite endpoint of one of following: (i) Two non-fasting plasma glucose levels > 11.1 mmol/L ≥ 30 days apart, (ii) oral hypoglycaemic drugs ≥ 30 days consecutively (iii) insulin therapy ≥ 30 days and (iv) HbA1c ≥ 48 mmol/L. Resolution of NODAT was defined as cessation of treatment or hyperglycaemia.

RESULTS

Total of 81/430 (19%) patients developed NODAT. Incidence and resolution of NODAT over time showed significantly different patterns between DCD and DBD liver graft recipients; early occurrence, high peak incidence and early resolution were seen in DCD. In multivariate logistic regression including age, ethnicity, HCV, tacrolimus level and pulsed steroids, only DCD was independently associated with NODAT at day 15 post-transplant (OR 6.5, 95% CI 2.3-18.4, P < 0.001), whereas age and pulsed steroids were significant factors between 30-90 days. Combined in multivariate Cox regression model for NODAT-free survival, graft type, age and pulsed steroids were each independent predictor for decreased NODAT-free survival in the first 90-postoperative days.

CONCLUSION

Early peak of NODAT in DCD graft recipients is a novel finding, occurring independently from known risk factors. Donor warm ischaemia and impact on insulin sensitivity should be further studied and could perhaps be associated with graft function.

Warm ischemic injury is reflected in the release of injury markers during cold preservation of the human liver

BACKGROUND

Liver transplantation plays a pivotal role in the treatment of patients with end-stage liver disease. Despite excellent outcomes, the field is strained by a severe shortage of viable liver grafts. To meet high demands, attempts are made to increase the use of suboptimal livers by both pretransplant recovery and assessment of donor livers. Here we aim to assess hepatic injury in the measurement of routine markers in the post-ischemic flush effluent of discarded human liver with a wide warm ischemic range.

METHODS

Six human livers discarded for transplantation with variable warm and cold ischemia times were flushed at the end of preservation. The liver grafts were flushed with NaCl or Lactated Ringer's, 2 L through the portal vein and 1 L through the hepatic artery. The vena caval effluent was sampled and analyzed for biochemical markers of injury; lactate dehydrogenase (LDH), alanine transaminase (ALT), and alkaline phosphatase (ALP). Liver tissue biopsies were analyzed for ATP content and histologically (H&E) examined.

RESULTS

The duration of warm ischemia in the six livers correlated significantly to the concentration of LDH, ALT, and ALP in the effluent from the portal vein flush. No correlation was found with cold ischemia time. Tissue ATP content at the end of preservation correlated very strongly with the concentration of ALP in the arterial effluent (P<0.0007, R2 = 0.96).

CONCLUSION

Biochemical injury markers released during the cold preservation period were reflective of the duration of warm ischemic injury sustained prior to release of the markers, as well as the hepatic energy status. As such, assessment of the flush effluent at the end of cold preservation may be a useful tool in evaluating suboptimal livers prior to transplantation, particularly in situations with undeterminable ischemic durations.

Subnormothermic ex vivo liver perfusion reduces endothelial cell and bile duct injury after donation after cardiac death pig liver transplantation

An ischemic-type biliary stricture (ITBS) is a common feature after liver transplantation using donation after cardiac death (DCD) grafts. We compared sequential subnormothermic ex vivo liver perfusion (SNEVLP; 33°C) with cold storage (CS) for the prevention of ITBS in DCD liver grafts in pig liver transplantation (n = 5 for each group). Liver grafts were stored for 10 hours at 4°C (CS) or preserved with combined 7-hour CS and 3-hour SNEVLP. Parameters of hepatocyte [aspartate aminotransferase (AST), international normalized ratio (INR), factor V, and caspase 3 immunohistochemistry], endothelial cell (EC; CD31 immunohistochemistry and hyaluronic acid), and biliary injury and function [alkaline phosphatase (ALP), total bilirubin, and bile lactate dehydrogenase (LDH)] were determined. Long-term survival (7 days) after transplantation was similar between the SNEVLP and CS groups (60% versus 40%, P = 0.13). No difference was observed between SNEVLP- and CS-treated animals with respect to the peak of serum INR, factor V, or AST levels within 24 hours. CD31 staining 8 hours after transplantation demonstrated intact EC lining in SNEVLP-treated livers (7.3 × 10(-4) ± 2.6 × 10(-4) cells/μm(2)) but not in CS-treated livers (3.7 × 10(-4) ± 1.3 × 10(-4) cells/μm(2) , P = 0.03). Posttransplant SNEVLP animals had decreased serum ALP and serum bilirubin levels in comparison with CS animals. In addition, LDH in bile fluid was lower in SNEVLP pigs versus CS pigs (14 ± 10 versus 60 ± 18 μmol/L, P = 0.02). Bile duct histology revealed severe bile duct necrosis in 3 of 5 animals in the CS group but none in the SNEVLP group (P = 0.03). Sequential SNEVLP preservation of DCD grafts reduces bile duct and EC injury after liver transplantation.

Liver transplantation with grafts obtained after cardiac death-current advances in mastering the challenge

The scarcity of donor livers has increased the interest in donation after cardiac death (DCD) as an additional pool to expand the availability of organs. However, the initial results of liver transplantation with DCD grafts have been suboptimal due to an increased rate of complications, as well as decreased graft survival. These challenges have led to many developments in DCD donation outcome, as well as basic and translational research. In this article we review the unique characteristics of DCD donors, nuances of DCD organ procurement, the effect of prolonged warm and cold ischemia times, and discuss major studies that compared DCD to donation after brain death liver transplantation, in terms of outcomes and complications. We also review the different methods of donor treatment that has been applied to ameliorate DCD organ outcome, and we discuss the role of machine perfusion techniques in organ reconditioning. We discuss the two major perfusion models, namely, hypothermic machine perfusion and normothermic machine perfusion; we compare both methods, and delineate their major differences.

Donor age as a risk factor in donation after circulatory death liver transplantation in a controlled withdrawal protocol programme

BACKGROUND

Results of donation after circulatory death (DCD) liver transplantation are impaired by graft loss, resulting mainly from non-anastomotic biliary stricture. Donor age is a risk factor in deceased donor liver transplantation, and particularly in DCD liver transplantation. At the authors' institute, age is not an absolute exclusion criterion for discarding DCD liver grafts, DCD donors receive comfort therapy before withdrawal, and cold ischaemia is minimized.

METHODS

All consecutive DCD liver transplantations performed from 2003 to 2012 were studied retrospectively. Three age groups were compared in terms of donor and recipient demographics, procurement and transplantation conditions, peak laboratory values during the first post-transplant 72 h, and results at 1 and 3 years.

RESULTS

A total of 70 DCD liver transplants were performed, including 32 liver grafts from donors aged 55 years or less, 20 aged 56-69 years, and 18 aged 70 years or more. The overall graft survival rate at 1 month, 1 and 3 years was 99, 91 and 72 per cent respectively, with no graft lost secondary to non-anastomotic stricture. No difference other than age was noted between the three groups for donor or recipient characteristics, or procurement conditions. No primary non-function occurred, but one patient needed retransplantation for artery thrombosis. Biliary complications were similar in the three groups. Graft and patient survival rates were no different at 1 and 3 years between the three groups (P = 0.605).

CONCLUSION

Results for DCD liver transplantation from younger and older donors were similar. Donor age above 50 years should not be a contraindication to DCD liver transplantation if other donor risk factors (such as warm and cold ischaemia time) are minimized.

HOPE for human liver grafts obtained from donors after cardiac death

BACKGROUND & AIMS

Due to ethical rules in most countries, long ischemia times are unavoidable prior to organ procurement of donors without a heartbeat, which can cause early graft failure after liver transplantation or late biliary strictures. Hypothermic oxygenated machine perfusion, used prior to graft implantation, may rescue these high risk organs.

METHODS

Eight patients with end stage liver diseases received human livers, obtained after controlled cardiac death (Maastricht category III), with a median donor warm ischemia time of 38 min, followed by a standard cold flush and static storage at 4 °C. Hypothermic oxygenated perfusion (HOPE) was applied for 1-2h prior to implantation through the portal vein. The HOPE-perfusate was cooled at 10 °C and oxygenated (pO2 60 kPa) using an ECOPS device (Organ Assist®). Perfusion pressure was maintained below 3 mmHg.

RESULTS

Each machine perfused liver graft disclosed excellent early function after transplantation. The release of liver enzymes and kidney function, as well as ICU and hospital stays were comparable or better than in matched liver grafts from brain death donors. No evidence of intrahepatic biliary complications could be documented within a median follow up of 8.5 months.

CONCLUSIONS

This is the first report on cold machine perfusion of human liver grafts obtained after cardiac arrest and subsequent transplantation. Application of HOPE appears well tolerated, easy-to-use, and protective against early and later injuries.

Graft cholangiopathy: etiology, diagnosis, and therapeutic strategies

BACKGROUND

Graft cholangiopathy has been recognized as a significant cause of morbidity, graft loss, and even mortality in patients after orthotopic liver transplantation. The aim of this review is to analyze the etiology, pathogenesis, diagnosis and therapeutic strategies of graft cholangiopathy after liver transplantation.

DATA SOURCE

A PubMed database search was performed to identify articles relevant to liver transplantation, biliary complications and cholangiopathy.

RESULTS

Several risk factors for graft cholangiopathy after liver transplantation have been identified, including ischemia/reperfusion injury, cytomegalovirus infection, immunological injury and bile salt toxicity. A number of strategies have been attempted to prevent the development of graft cholangiopathy, but their efficacy needs to be evaluated in large clinical studies. Non-surgical approaches may offer good results in patients with extrahepatic lesions. For most patients with complex hilar and intrahepatic biliary abnormalities, however, surgical repair or re-transplantation may be required.

CONCLUSIONS

The pathogenesis of graft cholangiopathy after liver transplantation is multifactorial. In the future, more efforts should be devoted to the development of more effective preventative and therapeutic strategies against graft cholangiopathy.