Differential rates of ischemic cholangiopathy and graft survival associated with induction therapy in DCD liver transplantation

Management of long-term complications from immunosuppression

This review discusses long-term complications from immunosuppressants after liver transplantation and the management of these complications. Common complications of calcineurin inhibitors include nephrotoxicity and metabolic diseases. Nephrotoxicity can be managed by targeting a lower drug level and/or adding an immunosuppressant of a different class. Metabolic disorders can be managed by treating the underlying condition and targeting a lower drug level. Gastrointestinal adverse effects and myelosuppression are common complications of antimetabolites that are initially managed with dose reduction or discontinuation if adverse events persist. Mammalian targets of rapamycin inhibitors are associated with myelosuppression, proteinuria, impaired wound healing, and stomatitis, which may require dose reduction or discontinuation. Induction agents and agents used for steroid-refractory rejection or antibody-mediated rejection are reviewed. Other rare complications of immunosuppressants are discussed as well.

Recipient age influences survival after liver transplant: Results of the French national cohort 2007-2017

BACKGROUND

In recent years, age at liver transplantation (LT) has markedly increased. In the context of organ shortage, we investigated the impact of recipient age on post-transplantation mortality.

METHODS

All adult patients who received a first LT between 2007 and 2017 were included in this cross-sectional study. Recipients' characteristics at the time of listing, donor and surgery data, post-operative complications and follow-up of vital status were retrieved from the national transplantation database. The impact of age on 5-year overall mortality post-LT was estimated using a flexible multivariable parametric model which was also used to estimate the association between age and 10-year net survival, accounting for expected age- and sex-related mortality.

RESULTS

Among the 7610 patients, 21.4% were aged 60-65 years, and 15.7% over 65. With increasing age, comorbidities increased but severity of liver disease decreased. Older recipient age was associated with decreased observed survival at 5 years after LT (p < .001), with a significant effect particularly during the first 2 years. The linear increase in the risk of death associated with age does not allow any definition of an age's threshold for LT (p = .832). Other covariates associated with an increased risk of 5-year death were dialysis and mechanical ventilation at transplant, transfusion during LT, hepatocellular carcinoma and donor age. Ten-year flexible net survival analysis confirmed these results.

CONCLUSION

Although there was a selection process for older recipients, increasing age at LT was associated with an increased risk of death, particularly in the first years after LT.

Strategies to Improve the Utilization and Function of DCD Livers

Despite the increased usage of livers from donation after circulatory death (DCD) donors in the last decade, many patients remaining on the waitlist who need a liver transplant. Recent efforts have focused on maximizing the utilization and outcomes of these allografts using advances in machine perfusion technology and other perioperative strategies such as normothermic regional perfusion (NRP). In addition to the standard donor and recipient matching that is required with DCD donation, new data regarding the impact of graft steatosis, extensive European experience with NRP, and the increasing use of normothermic and hypothermic machine perfusion have shown immense potential in increasing DCD organ overall utilization and improved outcomes. These techniques, along with viability testing of extended criteria donors, have generated early promising data to consider the use of higher-risk donor organs and more widespread adoption of these techniques in the United States. This review explores the most recent international literature regarding strategies to optimize the utilization and outcomes of DCD liver allografts, including donor-recipient matching, perioperative strategies including NRP versus rapid controlled DCD recovery, viability assessment of discarded livers, and postoperative strategies including machine perfusion versus pharmacologic interventions.

Current Use of Immunosuppression in Liver Transplantation

Since the first successful liver transplant in 1967, immunosuppression has allowed liver transplantation to become the standard treatment of end-stage liver disease. Over the decades, the rates of rejection have decreased, and patient survival outcomes have significantly improved in large part due to the introduction and advancements of immunosuppression medications. However, the adverse effects associated with long-term immunosuppression have created new challenges facing liver transplantation and added significantly to posttransplantation morbidity. This review presents the data and rationale for immunosuppression approaches, addresses the main controversies related to immunosuppression in liver transplantation, and explores some of the newer advancements in immunosuppressive drug therapy.

Modern-Day Practice of DCD Liver Transplantation: Controversies, Innovations, and Future Directions

PURPOSE OF REVIEW

Over the past decade, donation after circulatory death (DCD) liver transplantation has expanded in the United States due to improved surgical experience and perioperative management. Despite these advances, there remains a reluctance towards broader utilization of DCD liver allografts due to lack of standardized donation process, concern for inferior graft survival, and risk of ischemic cholangiopathy associated with temporary lack of oxygenated perfusion during withdrawal of life-supporting treatment during procurement.

RECENT FINDINGS

New perfusion technologies offer potential therapeutic options to mitigate biliary complications and expand utilization of marginal DCD grafts. As these modalities enter routine clinical practice, DCD utilization will continue to increase, and liver allocation policies in turn will evolve to reflect this growing practice. This review describes recent progress in DCD LT, current challenges with utilization of DCD liver allografts, and how novel technologies and policies could impact the future of the field.

Inhibition of SK2 and ER stress ameliorated inflammation and apoptosis in liver ischemia-reperfusion injury

Ischemia-reperfusion injury (IRI) remains a major cause of mortality and morbidity after liver surgery. Endoplasmic reticulum (ER) stress is a critical mechanism of inflammatory injury during hepatic IRI. In this study, we investigated the effect of sphingosine kinases 2 (SK2) on ER stress and hepatic IRI. We established hepatic IRI mice and hepatocellular hypoxia/reoxygenation in vitro model. We observed the SK2 and ER stress protein IRE1α expression. Then, we used an SK2 inhibitor and knocked down IRE1α/SK2, to observe the effect of SK2 during IRI. Our results showed that the expression of ER stress and SK2 was significantly elevated during hepatic IRI. Inhibition of SK2 ameliorated liver inflammation and reduced cell apoptosis in hepatic IRI mice. Consistently, we found that the inhibition of IRE1α also downregulated SK2 expression and reduced mitochondrial membrane permeability. Furthermore, the knockdown of SK2 could also reduce cell damage and reduce the expression of inflammatory factors but did not influence ER stress-related signaling pathway. Taken together, our results suggested that ER stress and SK2 played important and regulatory roles in hepatic IRI. Inhibition of ER stress and SK2 could significantly improve liver function after hepatic IRI.

The effectiveness and safety of antibody induction immunosuppression in a large cohort of United States pediatric liver transplant recipients

Data on the potential benefits and risks of induction therapy in pediatric liver transplantation (LT) are limited. This was a retrospective cohort study of 2748 pediatric LT recipients at 26 children's hospitals between January 1, 2006 to May 31, 2017 using data from the pediatric health information system linked to the United Network for Organ Sharing database. The induction regimen was obtained from the pediatric health information system day-by-day pharmacy resource utilization. Cox proportional hazards evaluated the association of induction regimen (none/corticosteroid-only, nondepleting, and depleting) on patient and graft survival. Additional outcomes, including opportunistic infections and posttransplant lymphoproliferative disorder, were studied using multivariable logistic regression. Overall, 64.9% received none/corticosteroid-only induction, whereas 28.1% received nondepleting, 8.3% received depleting, and 2.5% other antibody regimens. Differences in patient characteristics were small, but center practices were heterogeneous. Compared with none/corticosteroid-only induction, nondepleting induction was associated with reduced acute rejection (odd ratio [OR], 0.53; P <.001) but with the increased posttransplant lymphoproliferative disorder (OR, 1.75; P =.021). Depleting induction was associated with improved graft survival (hazard ratio [HR], 0.64; P =.028) but with increased noncytomegalovirus opportunistic infections (OR, 1.46; P =.046). Depleting induction is underused yet may offer long-term benefits in this large multicenter cohort. Greater consensus guidance in this aspect of pediatric LT care is warranted.

Protective mechanisms and current clinical evidence of hypothermic oxygenated machine perfusion (HOPE) in preventing post-transplant cholangiopathy

The development of cholangiopathies after liver transplantation impacts on the quality and duration of graft and patient survival, contributing to higher costs as numerous interventions are required to treat strictures and infections at the biliary tree. Prolonged donor warm ischaemia time in combination with additional cold storage are key risk factors for the development of biliary strictures. Based on this, the clinical implementation of dynamic preservation strategies is a current hot topic in the field of donation after circulatory death (DCD) liver transplantation. Despite various retrospective studies reporting promising results, also regarding biliary complications, there are only a few randomised-controlled trials on machine perfusion. Recently, the group from Groningen has published the first randomised-controlled trial on hypothermic oxygenated perfusion (HOPE), demonstrating a significant reduction of symptomatic ischaemic cholangiopathies with the use of a short period of HOPE before DCD liver implantation. The most likely mechanism for this important effect, also shown in several experimental studies, is based on mitochondrial reprogramming under hypothermic aerobic conditions, e.g. exposure to oxygen in the cold, with a controlled and slow metabolism of ischaemically accumulated succinate and simultaneous ATP replenishment. This unique feature prevents mitochondrial oxidative injury and further downstream tissue inflammation. HOPE treatment therefore supports livers by protecting them from ischaemia-reperfusion injury (IRI), and thereby also prevents the development of post-transplant biliary injury. With reduced IRI-associated inflammation, recipients are also protected from activation of the innate immune system, with less acute rejections seen after HOPE.

Antemortem Heparin in Organ Donation After Circulatory Death Determination: A Systematic Review of the Literature

Donation after circulatory death determination frequently involves antemortem heparin administration to mitigate peri-arrest microvascular thrombosis. We systematically reviewed the literature to: (1) describe heparin administration practices and (2) explore the effects on transplant outcomes. We searched MEDLINE and EMBASE for studies reporting donation after circulatory death determination heparin practices including use, dosage, and timing (objective 1). To explore associations between antemortem heparin and transplant outcomes (objective 2), we (1) summarized within-study comparisons and (2) used meta-regression analyses to examine associations between proportions of donors that received heparin and transplant outcomes. We assessed risk of bias using the Newcastle Ottawa Scale and applied the GRADE methodology to determine certainty in the evidence. For objective 1, among 55 eligible studies, 48 reported heparin administration to at least some donors (range: 15.8%-100%) at variable doses (up to 1000 units/kg) and times relative to withdrawal of life-sustaining therapy. For objective 2, 7 studies that directly compared liver transplants with and without antemortem heparin reported lower rates of primary nonfunction, hepatic artery thrombosis, graft failure at 5 y, or recipient mortality (low certainty of evidence). In contrast, meta-regression analysis of 32 liver transplant studies detected no associations between the proportion of donors that received heparin and rates of early allograft dysfunction, primary nonfunction, hepatic artery thrombosis, biliary ischemia, graft failure, retransplantation, or patient survival (very low certainty of evidence). In conclusion, antemortem heparin practices vary substantially with an uncertain effect on transplant outcomes. Given the controversies surrounding antemortem heparin, clinical trials may be warranted.

Immunosuppression in Donation After Circulatory Death Liver Transplantation: Can Induction Modify Graft Survival?

Recipients of donation after circulatory death (DCD) LTs historically have an increased risk of graft failure. Antibody induction (AI) with antithymocyte globulin (ATG) or anti-interleukin 2 receptor (anti-IL2R) immunotherapy may decrease the incidence of graft failure by mitigating ischemia/reperfusion injury. A retrospective review of the United Network for Organ Sharing (UNOS) database for LTs between 2002 and 2015 was conducted to determine whether ATG or anti-IL2R AI was associated with graft survival in DCD. A secondary endpoint was postoperative renal function as measured by estimated glomerular filtration rate at 6 and 12 months. Among DCD recipients, ATG (hazard ratio [HR] = 0.71; P = 0.03), but not anti-IL2R (HR = 0.82; P = 0.10), was associated with a decrease in graft failure at 3 years when compared with recipients without AI. ATG (HR = 0.90; P = 0.02) and anti-IL2R (HR = 0.94; P = 0.03) were associated with a decreased risk of graft failure in donation after brain death (DBD) liver recipients at 3 years compared with no AI. When induction regimens were compared between DCD and DBD, only ATG (HR = 1.19; P = 0.19), and not anti-IL2R (HR = 1.49; P < 0.01) or no AI (HR = 1.77; P < 0.01), was associated with similar survival between DCD and DBD. In conclusion, AI therapy with ATG was associated with improved longterm liver allograft survival in DCD compared with no AI. ATG was associated with equivalent graft survival between DCD and DBD, suggesting a beneficial role of immune cell depletion in DCD outcomes.

Donation after circulatory death liver transplantation: consensus statements from the Spanish Liver Transplantation Society

Livers from donation after circulatory death (DCD) donors are an increasingly more common source of organs for transplantation. While there are few high-level studies in the field of DCD liver transplantation, clinical practice has undergone progressive changes during the past decade, in particular due to mounting use of postmortem normothermic regional perfusion (NRP). In Spain, uncontrolled DCD has been performed since the late 1980s/early 1990s, while controlled DCD was implemented nationally in 2012. Since 2012, the rise in DCD liver transplant activity in Spain has been considerable, and the great majority of DCD livers transplanted in Spain today are recovered with NRP. A panel of the Spanish Liver Transplantation Society was convened in 2018 to evaluate current evidence and accumulated experience in DCD liver transplantation, in particular addressing issues related to DCD liver evaluation, acceptance criteria, and recovery as well as recipient selection and postoperative management. This panel has created a series of consensus statements for the standard of practice in Spain and has published these statements with the hope they might help guide other groups interested in implementing new forms of DCD liver transplantation and/or introducing NRP into their clinical practices.

The UK-DCD-Risk-Score - practical and new guidance for allocation of a specific organ to a recipient?

Introduction: Multiple factors contribute to the overall outcome in donation after circulatory death liver transplantation. The majority is however inconsistently reported with various acceptance criteria and thresholds, when to decline a specific graft. Recent improvement in outcome was based on an increased awareness of the cumulative risk, combining donor and recipient parameters, which encouraged the community to accept livers with an overall higher risk. Areas covered: This review pictures the large number of risk factors in this field with a special focus on parameters, which contribute to available prediction models. Next, features of the recently developed UK-DCD-Risk-Score, which led to a significantly impaired graft survival, above a suggested threshold of >10 score points, are discussed. The clinical impact of this new model on the background of other prediction tools with their subsequent limitations is highlighted in a next chapter. Finally, we provide suggestions, how to further improve outcomes in this challenging field of transplantation. Expert opinion: Despite the recent development of new prediction models, including the UK-DCD-Risk-Score, which provides a sufficient prediction of graft loss after DCD liver transplantation, the consideration of other confounders is essential to better understand the overall risk and metabolic liver status to improve the comparability of clinical studies. More uniform definitions and thresholds of individual risk factors are required.

Safety of Antithymocyte Globulin in Patients Undergoing Liver Transplantation With Livers From Donation After Circulatory Death Donors

Background: Studies suggest that rabbit-antithymocyte globulin (rATG) decreases biliary complications (BCs) after donation-after-circulatory-death-donor liver transplantation (DCD LTx), but safety data are lacking. Objective: Our aim was to assess the safety of rATG for this indication. The secondary end point was efficacy of rATG for this indication. Methods: Adult recipients of DCD LTx were divided into 2 cohorts: protocolized use of rATG in the modern era (July 1, 2013, to December 31, 2016) and a historical control without rATG (January 1, 2005, to June 30, 2013). Incidence of infection, leukopenia, and thrombocytopenia were compared for the safety assessment, incidence of BCs, ischemic cholangiopathy (IC), and transplant outcomes for the efficacy assessment. Results: A total of 83 patients met inclusion criteria: 42 in the historical cohort and 41 in the modern cohort. The modern cohort had significantly fewer bacterial infections at 3 months (historical 54.8% vs modern 23%; P = 0.004) and 1 year (historical 62.1% vs modern 34.2%, P = 0.004). The modern cohort also had fewer fungal infections at these time points (historical 33.3% and 47.9% vs modern 15% and 15%; P = 0.001). There were no significant differences in platelet or white blood cell reduction between groups. There was a nonsignificant, but numerical, trend toward reduced IC/BC in the modern cohort at 1 year (IC: historical 30.1% vs modern 13.2%, P = 0.08; BC: historical 51% vs modern 37.5%, P = 0.13). There was no difference in graft/patient survival. Conclusion and Relevance: Our data suggest no major safety issues with rATG in DCD LTx. Our study should ease clinical apprehension surrounding rATG use for this indication. Future prospective studies are needed to further evaluate the role of rATG and its impact on efficacy end points.

Graft Pre-conditioning by Peri-Operative Perfusion of Kidney Allografts With Rabbit Anti-human T-lymphocyte Globulin Results in Improved Kidney Graft Function in the Early Post-transplantation Period-a Prospective, Randomized Placebo-Controlled Trial

Introduction: Although prone to a higher degree of ischemia reperfusion injury (IRI), the use of extended criteria donor (ECD) organs has become reality in transplantation. We therefore postulated that peri-operative perfusion of renal transplants with anti-human T-lymphocyte globulin (ATLG) ameliorates IRI and results in improved graft function.

Methods: We performed a randomized, single-blinded, placebo-controlled trial involving 50 kidneys (KTx). Prior to implantation organs were perfused and incubated with ATLG (AP) (n = 24 kidney). Control organs (CP) were perfused with saline only (n = 26 kidney). Primary endpoint was defined as graft function reflected by serum creatinine at day 7 post transplantation (post-tx).

Results: AP-KTx recipients illustrated significantly better graft function at day 7 post-tx as reflected by lower creatinine levels, whereas no treatment effect was observed after 12 months surveillance. During the early hospitalization phase, 16 of the 26 CP-KTx patients required dialysis during the first 7 days post-tx, whereas only 10 of the 24 AP-KTx patients underwent dialysis. No treatment-specific differences were detected for various lymphocytes subsets in the peripheral blood of patients. Additionally, mRNA analysis of 0-h biopsies post incubation with ATLG revealed no changes of intragraft inflammatory expression patterns between AP and CP organs.

Conclusion: We here present the first clinical study on peri-operative organ perfusion with ATLG illustrating improved graft function in the early period post kidney transplantation.

Clinical Trial Registration:www.ClinicalTrials.gov, NCT03377283

Donation after brain death followed by circulatory death, a novel donation pattern, confers comparable renal allograft outcomes with donation after brain death

BACKGROUND

Organ donation after brain death (DBD) is the standard strategy for organ transplantation; however, the concept of brain death is not universally accepted due to cultural beliefs and barriers amongst billions of people worldwide. Hence, a novel donation pattern has been established in China which outlines the concept of donation after brain death followed by circulatory death (DBCD). Differently from any current donation classification, this new concept is formulated based on combination of recognizing brain death and circulatory death. Should approval be gained for this definition and approach, DBCD will pave a novel donation option for billions of people who cannot accept DBD due to their cultural beliefs.

METHODS

A multi-center, cohort study was conducted from February 2012 to December 2015. 523 kidney transplant recipients from four kidney transplant institutions were enrolled into the study, of which, 383 received kidneys from DBCD, and 140 from DBD. Graft and recipient survivals following transplantation were retrospectively analyzed. Postoperative complications including delayed graft function,, and acute rejection, were also analyzed for both groups.

RESULTS

DBCD could achieve comparable graft and recipient survivals in comparison with DBD (Log-rank P = 0.32 and 0.86,respectively). One-year graft and recipient survivals were equal between DBCD and DBD groups (97.4% versus 97.9%, P = 0.10;98.4% versus 98.6%, P = 1.0, respectively). Furthermore, DBCD did not increase incidences of postoperative complications compared with DBD, including delayed graft function (19.3% versus 22.1%, P = 0.46) and acute rejection (9.1% versus 8.6%, P = 1.0). Additionally, antithymocyte globulin as induction therapy and shorter warm ischemia time decreased incidence of delayed graft function in DBCD group (16.8% on antithymocyte globulin versus 27.2% on basiliximab, P = 0.03; 16.7% on ≤18 min versus 26.7% on > 18 min group, P = 0.03).

CONCLUSIONS

Kidney donation through DBCD achieves equally successful outcomes as DBD, and could provide a feasible path to graft availability for billions of people who face barriers to organ donation from DBD.

A literature-based cost analysis of tissue plasminogen activator for prevention of biliary stricture in donation after circulatory death liver transplantation

INTRODUCTION

This study sought to approximate the cost-effectiveness of tPA utilization for prevention of biliary strictures (PTBS) in donation after circulatory death liver transplantation (DCD-LT).

METHODS

Previously-reported PTBS rates in DCD-LT with and without tPA were used to calculate the number needed to treat (NNT) for prevention of one PTBS. The incremental cost of PTBS was then used to determine the cost effectiveness of tPA for prevention of PTBS.

RESULTS

The incidence of PTBS in the setting of tPA administration was 20%, while incidence in patients without tPA use was 43% (p < 0.001). Meta-analysis demonstrated a risk reduction of 15.7%, which translated into a NNT of 6.4. Cost associated with treating 6.4 patients was $50,353. Based on an incremental cost of $81,888 associated with PTBS management, use of tPA in DCD-LT protocols was estimated to save $31,528 per PTBS prevented.

CONCLUSION

Utilization of tPA in DCD-LT protocols represents one possible cost-effective strategy for prevention of PTBS in DCD-LT.

Liver Transplantation Using Donation After Brain and Cardiac Death: A Single-Center Experience in China

BACKGROUND

Liver transplantation (LTx) using donation after brain and cardiac death (DBCD) has increased steadily in China. The aims of this study were to evaluate the outcomes of DBCD LTx and to assess its feasibility to expand the donor pool.

METHODS

We retrospectively analyzed the clinical characteristics of DBCD donors and recipients, survival of allografts and recipients, and prognostic factors in DBCD LTx recipients from March 2010 to December 2014 in our institution.

RESULTS

DBCD LTx (n = 102) were performed in our institution during the research period, and the successful donation rate was 26.0%. Mean warm ischemia time and cold ischemia time were 14.39 minutes and 5.29 hours, respectively. The overall and biliary complication rates were 45.1% and 16.7%, respectively. Donor age (P = .043), intra-operative blood loss (P = .048), and operation time (P = .045) were significantly different between the complication and non-complication groups. The 1-, 2-, and 3-year survival rates of patients and grafts were 88.0%, 84.6%, 84.6%, and 85.7%, 78.6%, and 78.6%, respectively. The 1- and 2-year overall survival rates of hepatocellular carcinoma patients were 91.9% and 80.5%, respectively whereas the recurrence-free survival rates were 84.9% and 77.2%, respectively. The patient and graft survival rates were not statistically different between the <55-year and ≥55 year groups, but complication rate was higher in the older group than in the younger group (P = .003).

CONCLUSIONS

The outcome of DBCD LTx is favorable in our institution, with careful donor and recipient selection and careful peri-operative management. DBCD is an optimized solution for organ shortage in today's China.

Liver transplant outcomes using ideal donation after circulatory death livers are superior to using older donation after brain death donor livers

Multiple reports have demonstrated that liver transplantation following donation after circulatory death (DCD) is associated with poorer outcomes when compared with liver transplantation from donation after brain death (DBD) donors. We hypothesized that carefully selected, underutilized DCD livers recovered from younger donors have excellent outcomes. We performed a retrospective study of the United Network for Organ Sharing database to determine graft survivals for patients who received liver transplants from DBD donors of age ≥ 60 years, DBD donors < 60 years, and DCD donors < 50 years of age. Between January 2002 and December 2014, 52,271 liver transplants were performed in the United States. Of these, 41,181 (78.8%) underwent transplantation with livers from DBD donors of age < 60 years, 8905 (17.0%) from DBD donors ≥ 60 years old, and 2195 (4.2%) livers from DCD donors < 50 years of age. DCD livers of age < 50 years with < 6 hours of cold ischemia time (CIT) had superior graft survival when compared with DBD livers ≥ age 60 years (P < 0.001). In 2014, there were 133 discarded DCD livers; of these, 111 (83.4%) were from donors < age 50 years old. Young DCD donor livers (age < 50 years old) with short CITs yield results better than that seen with DBD livers > 60 years old. Careful donor organ and recipient selection can lead to excellent results, despite previous reports suggesting otherwise. Increased acceptance of these DCD livers would lead to shorter wait list times and increased national liver transplant rates. Liver Transplantation 22 1197-1204 2016 AASLD.

Rapamycin Attenuates Mouse Liver Ischemia and Reperfusion Injury by Inhibiting Endoplasmic Reticulum Stress

The roles of endoplasmic reticulum (ER) stress in liver ischemia and reperfusion injury (IRI) have been well recognized. However, the impact of rapamycin (Rapa), a broadly used immunosuppressive agent in human liver transplantation, on ER stress during IRI remains unclear. This study was designed to investigate the roles of Rapa in the regulation of ER stress in vivo and in vitro. In a mouse liver partial warm ischemia and reperfusion mode, we demonstrated that Rapa markedly protected livers from IRI, as evidenced by serum alanine aminotransferase (sALT) levels and liver histology. Then we also confirmed the protection of Rapa from thapsigargin (Tg)-induced cell death in primary hepatocytes. Both in vivo and in vitro experiments showed that the ER stress markers were markedly up-regulated by IRI and Tg treatment, whereas they were down-regulated by Rapa pretreatment, as monitored by Western blot at the protein levels and by quantitative reverse transcription polymerase chain reaction (RT-PCR) at the messenger RNA (mRNA) levels. In addition, it was also revealed that Rapa was able to remarkably inhibit the mammalian target of rapamycin (mTOR) pathway and enhance autophagy both in IR-stressed livers and Tg-treated primary hepatocytes. Thus, these results suggest that Rapa protects livers from IRI through inhibiting the ER stress pathway.

First Comparison of Hypothermic Oxygenated PErfusion Versus Static Cold Storage of Human Donation After Cardiac Death Liver Transplants: An International-matched Case Analysis

BACKGROUND

Exposure of donor liver grafts to prolonged periods of warm ischemia before procurement causes injuries including intrahepatic cholangiopathy, which may lead to graft loss. Due to unavoidable prolonged ischemic time before procurement in donation after cardiac death (DCD) donation in 1 participating center, each liver graft of this center was pretreated with the new machine perfusion "Hypothermic Oxygenated PErfusion" (HOPE) in an attempt to improve graft quality before implantation.

METHODS

HOPE-treated DCD livers (n = 25) were matched and compared with normally preserved (static cold preservation) DCD liver grafts (n = 50) from 2 well-established European programs. Criteria for matching included duration of warm ischemia and key confounders summarized in the balance of risk score. In a second step, perfused and unperfused DCD livers were compared with liver grafts from standard brain dead donors (n = 50), also matched to the balance of risk score, serving as baseline controls.

RESULTS

HOPE treatment of DCD livers significantly decreased graft injury compared with matched cold-stored DCD livers regarding peak alanine-aminotransferase (1239 vs 2065 U/L, P = 0.02), intrahepatic cholangiopathy (0% vs 22%, P = 0.015), biliary complications (20% vs 46%, P = 0.042), and 1-year graft survival (90% vs 69%, P = 0.035). No graft failure due to intrahepatic cholangiopathy or nonfunction occurred in HOPE-treated livers, whereas 18% of unperfused DCD livers needed retransplantation. In addition, HOPE-perfused DCD livers achieved similar results as control donation after brain death livers in all investigated endpoints.

CONCLUSIONS

HOPE seems to offer important benefits in preserving higher-risk DCD liver grafts.

Kupffer cells and liver transplantation

Nowadays, liver transplantation is globally considered the most effective treatment for end-stage liver diseases. Ischemia-reperfusion (I/R) injury and immune rejection response (IRR) are the two major imperfections which severely affect the recipients' prognosis and survival rate without satisfactory clinical management strategies. Therefore, exploring effective methods to improve I/R injury and IRR have important clinical significance under circumstances of shortage of donor livers. Kupffer cells (KCs) are the largest population of antigen representing cells (APCs) which settle in the liver. As the first defensive line of the live, KCs exhibit various biological effects. However, the exact mechanisms responsible for the role of KCs in I/R injury and IRR remain elusive. We hereby review the current finding about the role of KCs in I/R injury and IRR.