Hypothermic oxygenated machine perfusion (HOPE) for orthotopic liver transplantation of human liver allografts from extended criteria donors (ECD) in donation after brain death (DBD): a prospective multicentre randomised controlled trial (HOPE ECD-DBD)

Britannin inhibits hepatocellular carcinoma development and metastasis through the GSK-3β/β-catenin signaling pathway

BACKGROUND

Hepatocellular carcinoma (HCC) stands out as a significant contributor to cancer-related death. Traditional Chinese Medicine (TCM) offers several advantages in the treatment of HCC. Britannin, a pivotal compound in Inulae Flos, has demonstrated pharmacological effects against various cancers, yet research on its specific anti-HCC effects remains limited.

PURPOSE

This study aims to explore the anti-HCC effects of britannin and its underlying mechanism.

METHODS

MTT assay, clone formation assay and flow cytometry were utilized to detect the cell activity, proliferation ability and apoptosis of britannin against HCC cell lines. Cell migration and invasion abilities of HCC cell lines treated with britannin were evaluated by wound-healing assay and transwell migration and invasion assay. H22 xenografted tumor mouse model was constructed and britannin treatment was performed to observe the effect of britannin on HCC tumors. The expression levels of liver cancer biomarkers AFP, AFP-L3, APT and TGF-β were detected by Elisa, and the histopathology was observed by HE staining. Network pharmacology and molecular docking were used to predict the possible signaling pathway of anti-HCC effect of britannin. The surface plasmon resonance (SPR) experiment was used to verify the interaction between britannin and proteins. The cell kinase activity function experiment was employed to detect the effect of britannin on enzyme activity. RT-qPCR and Western-Blot were used to verify the effect of britannin on the mRNA expressions of key genes and protein levels related to GSK-3β/β-catenin pathway in HCC cells and tumor tissues in mice.

RESULTS

In vitro experiments showed that britannin could inhibit the activity, proliferation, migration and invasion abilities of HCC cells, while promoting their apoptosis. In vivo experiments revealed that britannin exerted inhibitory effects on the growth of transplanted liver cancer tumors, reducing the inflammatory infiltration and the expression levels of AFP, AFP-L3, APT and TGF-β of liver cancer markers in transplanted mice. Network pharmacology and molecular docking predicted that cell adhesion factors and GSK-3β/β-catenin pathway might be the related signaling pathway and had potential docking activity with key proteins. The SPR experiments elucidated the molecular interaction between britannin and GSK-3β. Enzyme activity assays indicated that britannin could modulate the functional activity of GSK-3β kinase. RT-qPCR suggested britannin could regulate the mRNA expressions of β-catenin, GSK-3β, E-cadherin and NCadherin. Western-Blot further verified that britannin could significantly up-regulate the expression of GSK-3β and down-regulate the expression of p-GSK-3β and β-catenin. At the same time, the expression of E-cadherin increased and NCadherin decreased, thereby reducing the occurrence of EMT and inhibiting the metastasis of HCC.

CONCLUSION

In conclusion, britannin could inhibit the growth, development and metastasis of HCC, and its mechanism may be related to the regulation of GSK-3β/β-catenin signaling pathway to inhibit epithelial-mesenchymal transition of HCC.

Machine perfusion of the liver and in vivo animal models: A systematic review of the preclinical research landscape

Machine perfusion (MP) is often referred to as one of the most promising advancements in liver transplantation research of the last few decades, with various techniques and modalities being evaluated in preclinical studies using animal models. However, low scientific rigor and subpar reporting standards lead to limited reproducibility and translational potential, hindering progress. This pre-registered systematic review (PROSPERO: CRD42021234667) aimed to provide a thematic overview of the preclinical research landscape on MP in liver transplantation using in vivo transplantation models and to explore methodological and reporting standards, using the ARRIVE (Animal Research: Reporting of In Vivo Experiments) score. In total 56 articles were included. Studies were evenly distributed across Asia, Europe, and the Americas. Porcine models were used in 57.1% of the studies, followed by rats (39.3%) and dogs (3.6%). In terms of graft type, 55.4% of the studies used donation after cardiac death grafts, while donation after brain death grafts accounted for 37.5%. Regarding MP modalities, the distribution was as follows: 41.5% of articles utilized hypothermic MP, 21.5% normothermic MP, 13.8% subnormothermic MP, and 16.9% utilized hypothermic oxygenated MP. The stringent documentation of ARRIVE elements concerning precise experimental execution, group size and selection, the choice of statistical methods, as well as adherence to the principles of the 3Rs, was notably lacking in the majority of publications, with less than 30% providing comprehensive details. Postoperative analgesia and antibiotics treatment were not documented in 82.1% of all included studies. None of the analyzed studies fully adhered to the ARRIVE Guidelines. In conclusion, the present study emphasizes the importance of adhering to reporting standards to promote reproducibility and adequate animal welfare in preclinical studies in machine perfusion. At the same time, it highlights a clear deficiency in this field, underscoring the need for further investigations into animal welfare-related topics.

Improved outcomes after hypothermic oxygenated machine perfusion in liver transplantation-Long-term follow-up of a multicenter randomized controlled trial

BACKGROUND

While 4 randomized controlled clinical trials confirmed the early benefits of hypothermic oxygenated machine perfusion (HOPE), high-level evidence regarding long-term clinical outcomes is lacking. The aim of this follow-up study from the HOPE-ECD-DBD trial was to compare long-term outcomes in patients who underwent liver transplantation using extended criteria donor allografts from donation after brain death (ECD-DBD), randomized to either HOPE or static cold storage (SCS).

METHODS

Between September 2017 and September 2020, recipients of liver transplantation from 4 European centers receiving extended criteria donor-donation after brain death allografts were randomly assigned to HOPE or SCS (1:1). Follow-up data were available for all patients. Analyzed endpoints included the incidence of late-onset complications (occurring later than 6 months and graded according to the Clavien-Dindo Classification and the Comprehensive Complication Index) and long-term graft survival and patient survival.

RESULTS

A total of 46 patients were randomized, 23 in both arms. The median follow-up was 48 months (95% CI: 41-55). After excluding early perioperative morbidity, a significant reduction in late-onset morbidity was observed in the HOPE group (median reduction of 23 Comprehensive Complication Index-points [p=0.003] and lower incidence of major complications [Clavien-Dindo ≥3, 43% vs. 85%, p=0.009]). Primary graft loss occurred in 13 patients (HOPE n=3 vs. SCS n=10), resulting in a significantly lower overall graft survival (p=0.029) and adverse 1-, 3-, and 5-year survival probabilities in the SCS group, which did not reach the level of significance (HOPE 0.913, 0.869, 0.869 vs. SCS 0.783, 0.606, 0.519, respectively).

CONCLUSIONS

Our exploratory findings indicate that HOPE reduces late-onset morbidity and improves long-term graft survival providing clinical evidence to further support the broad implementation of HOPE in human liver transplantation.

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.

The impact of postoperative complications on oncological outcomes of liver transplantation for hepatocellular carcinoma: A competing risk analysis

OBJECTIVE

To investigate the influence of postoperative complications on tumor-related (TRD), disease-free survival (DFS) and overall survival (OS) in patients undergoing liver transplant (LT) for hepatocellular carcinoma (HCC).

METHODS

We retrospectively evaluated 425 LTs for HCC from 2010 to 2019. Postoperative complications were classified according to Comprehensive Complication Index (CCI) and the posttransplant risk of TRD assessed through Metroticket 2.0 calculator. The population was stratified into high-risk and low-risk cohorts based on the predicted TRD risk of 80%. In a second step, we re-evaluated TRD, DFS and OS of both cohorts according to a further stratification based on 47.3 points of CCI cut-off.

RESULTS

In the low-risk cohort, we observed a significantly better DFS (84% vs. 46%, p<0.001), TRD (3% vs. 26%, p<0.001) and OS (89% vs. 62%, p<0.001) in the group with CCI < 47.3. In the high-risk cohort, patients with CCI < 47.3 had significantly better DFS (50% vs. 23%, p = 0.003) and OS (68% vs. 42%, p = 0.02) and a comparable TRD (22% vs. 31%, p = 0.142).

CONCLUSIONS

A complicated postoperative course negatively influenced long-term survival. This poorer oncological outcome associated with in-hospital postoperative complications suggests that every effort should be made to improve the early posttransplant course in HCC patients, including a careful donor-to recipient match and use of new perfusion technologies.

Machine perfusion in liver transplantation

BACKGROUND

Liver transplantation is the only chance of cure for people with end-stage liver disease and some people with advanced liver cancers or acute liver failure. The increasing prevalence of these conditions drives demand and necessitates the increasing use of donated livers which have traditionally been considered suboptimal. Several novel machine perfusion preservation technologies have been developed, which attempt to ameliorate some of the deleterious effects of ischaemia reperfusion injury. Machine perfusion technology aims to improve organ quality, thereby improving outcomes in recipients of suboptimal livers when compared to traditional static cold storage (SCS; ice box).

OBJECTIVES

To evaluate the effects of different methods of machine perfusion (including hypothermic oxygenated machine perfusion (HOPE), normothermic machine perfusion (NMP), controlled oxygenated rewarming, and normothermic regional perfusion) versus each other or versus static cold storage (SCS) in people undergoing liver transplantation.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was 10 January 2023.

SELECTION CRITERIA

We included randomised clinical trials which compared different methods of machine perfusion, either with each other or with SCS. Studies comparing HOPE via both hepatic artery and portal vein, or via portal vein only, were grouped. The protocol detailed that we also planned to include quasi-randomised studies to assess treatment harms.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. overall participant survival, 2. quality of life, and 3. serious adverse events. Secondary outcomes were 4. graft survival, 5. ischaemic biliary complications, 6. primary non-function of the graft, 7. early allograft function, 8. non-serious adverse events, 9. transplant utilisation, and 10. transaminase release during the first week post-transplant. We assessed bias using Cochrane's RoB 2 tool and used GRADE to assess certainty of evidence.

MAIN RESULTS

We included seven randomised trials (1024 transplant recipients from 1301 randomised/included livers). All trials were parallel two-group trials; four compared HOPE versus SCS, and three compared NMP versus SCS. No trials used normothermic regional perfusion. When compared with SCS, it was uncertain whether overall participant survival was improved with either HOPE (hazard ratio (HR) 0.91, 95% confidence interval (CI) 0.42 to 1.98; P = 0.81, I2 = 0%; 4 trials, 482 recipients; low-certainty evidence due to imprecision because of low number of events) or NMP (HR 1.08, 95% CI 0.31 to 3.80; P = 0.90; 1 trial, 222 recipients; very low-certainty evidence due to imprecision and risk of bias). No trials reported quality of life. When compared with SCS alone, HOPE was associated with improvement in the following clinically relevant outcomes: graft survival (HR 0.45, 95% CI 0.23 to 0.87; P = 0.02, I2 = 0%; 4 trials, 482 recipients; high-certainty evidence), serious adverse events in extended criteria DBD liver transplants (OR 0.45, 95% CI 0.22 to 0.91; P = 0.03, I2 = 0%; 2 trials, 156 participants; moderate-certainty evidence) and clinically significant ischaemic cholangiopathy in recipients of DCD livers (OR 0.31, 95% CI 0.11 to 0.92; P = 0.03; 1 trial, 156 recipients; high-certainty evidence). In contrast, NMP was not associated with improvement in any of these clinically relevant outcomes. NMP was associated with improved utilisation compared with SCS (one trial found a 50% lower rate of organ discard; P = 0.008), but the reasons underlying this effect are unknown. We identified 11 ongoing studies investigating machine perfusion technologies.

AUTHORS' CONCLUSIONS

In situations where the decision has been made to transplant a liver donated after circulatory death or donated following brain death, end-ischaemic HOPE will provide superior clinically relevant outcomes compared with SCS alone. Specifically, graft survival is improved (high-certainty evidence), serious adverse events are reduced (moderate-certainty evidence), and in donors after circulatory death, clinically relevant ischaemic biliary complications are reduced (high-certainty evidence). There is no good evidence that NMP has the same benefits over SCS in terms of these clinically relevant outcomes. NMP does appear to improve utilisation of grafts that would otherwise be discarded with SCS; however, the reasons for this, and whether this effect is specific to NMP, is not clear. Further studies into NMP viability criteria and utilisation, as well as head-to-head trials with other perfusion technologies are needed. In the setting of donation following circulatory death transplantation, further trials are needed to assess the effect of these ex situ machine perfusion methods against, or in combination with, normothermic regional perfusion.

End-ischemic hypothermic oxygenated perfusion for extended criteria donors in liver transplantation: a multicenter, randomized controlled trial-HOPExt

BACKGROUND

Given the scarce donor supply, an increasing number of so-called marginal or extended criteria donor (ECD) organs are used for liver transplantation. These ECD liver grafts are however known to be associated with a higher rate of early allograft dysfunction and primary non-function because of a greater vulnerability to ischemia-reperfusion injury. The end-ischemic hypothermic oxygenated machine perfusion (HOPE) technique may improve outcomes of liver transplantation with ECD grafts by decreasing reperfusion injury.

METHODS

HOPExt trial is a comparative open-label, multicenter, national, prospective, randomized, controlled study, in two parallel groups, using static cold storage, the gold standard procedure, as control. The trial will enroll adult patients on the transplant waiting list for liver failure or liver cirrhosis and/or liver malignancy requiring liver transplantation and receiving an ECD liver graft from a brain-dead donor. In the experimental group, ECD liver grafts will first undergo a classical static cold (4 °C) storage followed by a hypothermic oxygenated perfusion (HOPE) for a period of 1 to 4 h. The control group will consist of the classic static cold storage which is the gold standard procedure in liver transplantation. The primary objective of this trial is to study the efficacy of HOPE used before transplantation of ECD liver grafts from brain-dead donors in reducing postoperative early allograft dysfunction within the first 7 postoperative days compared to simple cold static storage.

DISCUSSION

We present in this protocol all study procedures in regard to the achievement of the HOPExt trial, to prevent biased analysis of trial outcomes and improve the transparency of the trial results. Enrollment of patients in the HOPExt trial has started on September 10, 2019, and is ongoing.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03929523. Registered on April 29, 2019, before the start of inclusion.

Liver Transplantation for Hepatic Metastases from Colorectal Cancer: Current Knowledge and Open Issues

More than 40% of patients with colorectal cancer present liver metastases (CRLM) during the course of their disease and up to 50% present with unresectable disease. Without surgical interventions, survival for patients treated with systemic therapies alone is dismal. In the past, liver transplantation (LT) for patients with unresectable CRLM failed to show any survival benefit due to poor selection, ineffective chemotherapeutic regimens, unbalanced immunosuppression and high perioperative mortality. Since then and for many years LT for CRLM was abandoned. The turning point occurred in 2013, when the results from the Secondary Cancer (SECA I) pilot study performed at Oslo University were published reporting a 60% 5-year overall survival after LT in patients with unresectable CRLM. These results effectively reignited the interest in LT as a potential therapy for CRLM, and several trials are undergoing. The aims of this article are to give a comprehensive overview of the available evidence on LT for CRLM, discuss the open issues in this rapidly evolving field, and highlight possible ways to address the future of this fascinating therapeutic alternative for selected patients with CRLM.

Hypothermic Oxygenated Machine Perfusion (HOPE) Prior to Liver Transplantation Mitigates Post-Reperfusion Syndrome and Perioperative Electrolyte Shifts

(1) Background: Post-reperfusion syndrome (PRS) and electrolyte shifts (ES) represent considerable challenges during liver transplantation (LT) being associated with significant morbidity. We aimed to investigate the impact of hypothermic oxygenated machine perfusion (HOPE) on PRS and ES in LT. (2) Methods: In this retrospective study, we compared intraoperative parameters of 100 LTs, with 50 HOPE preconditioned liver grafts and 50 grafts stored in static cold storage (SCS). During reperfusion phase, prospectively registered serum parameters and vasopressor administration were analyzed. (3) Results: Twelve percent of patients developed PRS in the HOPE cohort vs. 42% in the SCS group (p = 0.0013). Total vasopressor demand in the first hour after reperfusion was lower after HOPE pretreatment, with reduced usage of norepinephrine (−26%; p = 0.122) and significant reduction of epinephrine consumption (−52%; p = 0.018). Serum potassium concentration dropped by a mean of 14.1% in transplantations after HOPE, compared to a slight decrease of 1% (p < 0.001) after SCS. The overall incidence of early allograft dysfunction (EAD) was reduced by 44% in the HOPE group (p = 0.04). (4) Conclusions: Pre-transplant graft preconditioning with HOPE results in higher hemodynamic stability during reperfusion and lower incidence of PRS and EAD. HOPE has the potential to mitigate ES by preventing hyperpotassemic complications that need to be addressed in LT with HOPE-pre-treated grafts.

Four Decades of Clinical Liver Transplantation Research: Results of a Comprehensive Bibliometric Analysis

BACKGROUND

Nearly 40 y have passed since the 1983 National Institutes of Health Consensus-Development-Conference, which has turned liver transplantation (LT) from a clinical experiment into a routine therapeutic modality. Since' clinical LT has changed substantially. We aimed to comprehensively analyze the publication trends in the most-cited top-notch literature in LT science over a 4-decade period.

METHODS

A total of 106 523 items were identified between January 1981 and May 2021 from the Web of Science Core Collection. The top 100 articles published were selected using 2 distinct citation-based strategies to minimize bias. Various bibliometric tools were used for data synthesis and visualization.

RESULTS

The citation count for the final dataset of the top 100 articles ranged from 251 to 4721. Most articles were published by US authors (n = 61). The most prolific institution was the University of Pittsburgh (n = 15). The highest number of articles was published in Annals of Surgery, Hepatology, and Transplantation ; however, Hepatology publications resulted in the highest cumulative citation of 9668. Only 10% of the articles were classified as evidence level 1. Over 90% of first/last authors were male. Our data depict the evolution of research focus over 40 y. In part, a disproportional flow of citations was observed toward already well-cited articles. This might also project a slowed canonical progress, which was described in other fields of science.

CONCLUSIONS

This study highlights key trends based on a large dataset of the most-cited articles over a 4-decade period. The present analysis not only provides an important cross-sectional and forward-looking guidance to clinicians, funding bodies, and researchers but also draws attention to important socio-academic or demographic aspects in LT.

Liver Machine Perfusion—When Physiopathology Matters

Liver transplantation (LT) has become a victim of its own success [...]

Mitochondria and Cancer Recurrence after Liver Transplantation—What Is the Benefit of Machine Perfusion?

Tumor recurrence after liver transplantation has been linked to multiple factors, including the recipient’s tumor burden, donor factors, and ischemia-reperfusion injury (IRI). The increasing number of livers accepted from extended criteria donors has forced the transplant community to push the development of dynamic perfusion strategies. The reason behind this progress is the urgent need to reduce the clinical consequences of IRI. Two concepts appear most beneficial and include either the avoidance of ischemia, e.g., the replacement of cold storage by machine perfusion, or secondly, an endischemic organ improvement through perfusion in the recipient center prior to implantation. While several concepts, including normothermic perfusion, were found to reduce recipient transaminase levels and early allograft dysfunction, hypothermic oxygenated perfusion also reduced IRI-associated post-transplant complications and costs. With the impact on mitochondrial injury and subsequent less IRI-inflammation, this endischemic perfusion was also found to reduce the recurrence of hepatocellular carcinoma after liver transplantation. Firstly, this article highlights the contributing factors to tumor recurrence, including the surgical and medical tissue trauma and underlying mechanisms of IRI-associated inflammation. Secondly, it focuses on the role of mitochondria and associated interventions to reduce cancer recurrence. Finally, the role of machine perfusion technology as a delivery tool and as an individual treatment is discussed together with the currently available clinical studies.

Metabolomics and integrated network pharmacology analysis reveal SNKAF decoction suppresses cell proliferation and induced cell apoptisis in hepatocellular carcinoma via PI3K/Akt/P53/FoxO signaling axis

BACKGROUND

There is no comprehensive treatment method for hepatocellular carcinoma (HCC); hence, research and development are still focused on systemic therapies, including drugs. Sinikangai fang (SNKAF) decoction, a classic Chinese herbal prescription, has been widely used to treat liver cancer. However, there is no research on its core active component and target.

METHODS

Mouse models were established to measure the anticancer effect of SNKAF decoction on HCC. Further, we investigated the effect of SNKAF decoction on inhibition of hepatoma cells proliferation using cell viability, cloning and invasion assays in vitro. The components of SNKAF were collected from the Traditional Chinese Medicine Systems Pharmacology (TCMSP) database and TCM@Taiwan database. Metabolomic analysis was used to identify the potential genes and pathways in HCC treated with SNKAF decoction. Then, the expression of phosphoinositide 3-kinase (PI3K), Akt, P53, FoxO proteins of the potential signal pathways were detected using Western blot.

RESULTS

The animal experiments showed that SNKAF decoction inhibited tumor growth (P < 0.05) and induced no weight loss in the mice. In vitro data showed that HCCLM3 and MHCC97H cell proliferation was inhibited by SNKAF serum in a time- and concentration dependent manner. Further combined analysis network pharmacology with metabonomics showed that 217 target genes overlapped. The core target genes included BCL2, MCL1, Myc, PTEN, gsk3b, CASP9, CREB1, MDM2, pt53 and CCND1. Cancer-associated pathways were largely involved in SNKAF mechanisms, including P53, FoxO, and PI3K/Akt signaling pathways, which are closely related to induced-tumor cell apoptosis. In addition, Western bolt verified that 10% SNKAF serum significantly affected the main proteins of PI3K/Akt/P53/FoxO signaling pathway in both cell lines.

CONCLUSION

SNKAF decoction-containing serum inhibited HCCLM3 and MHCC97H cell proliferation, migration, invasion, and induced-tumor cell apoptosis in-vivo. We confirmed that SNKAF decoction is a promising alternative treatments for HCC patients.

The Benefits of Fibrinolysis Combined with Venous Systemic Oxygen Persufflation (VSOP) in a Rat Model of Donation after Circulatory Death and Orthotopic Liver Transplantation

Organ shortage has led to the increasing utilization of livers retrieved from donors after circulatory death (DCD). These pre-damaged organs are susceptible to further warm ischemia and exhibit minimal tolerance for cold storage. The aim was thus to examine the effects of fibrinolysis combined with Venous Systemic Oxygen Persufflation (VSOP) on the preservation of DCD livers in vivo. Livers of male Lewis rats were explanted after 45 min of warm ischemia, cold-stored for 18 h, and transplanted into a recipient animal. Livers were left untreated or underwent either VSOP or fibrinolysis via Streptokinase (SK) or received combined SK and VSOP. Combined treatment exhibited improved microvascular flow at 168 h (p = 0.0009) and elevated microperfusion velocity at 24 h post-transplantation (p = 0.0007). Combination treatment demonstrated increased portal venous flow (PVF) at 3 and 24 h post-transplantation (p = 0.0004, p < 0.0001), although SK and VSOP analogously achieved increases at 24 h (p = 0.0036, p = 0.0051). Enzyme release was decreased for combination treatment (p = 0.0002, p = 0.0223) and lactate dehydrogenase (LDH) measurements were lower at 24 h post-transplantation (p = 0.0287). Further supporting findings have been obtained in terms of serum cytokine levels and in the alterations of endothelial injury markers. The combination treatment of SK + VSOP might provide improved organ integrity and viability and may therefore warrant further investigation as a potential therapeutic approach in the clinical setting of DCD.

Prolonged dual hypothermic oxygenated machine preservation (DHOPE-PRO) in liver transplantation: study protocol for a stage 2, prospective, dual-arm, safety and feasibility clinical trial

Introduction

End-ischaemic preservation of a donor liver by dual hypothermic oxygenated machine perfusion (DHOPE) for 2 hours prior to transplantation is sufficient to mitigate ischaemia-reperfusion damage and fully restore cellular energy levels. Clinical studies have shown beneficial outcomes after transplantation of liver grafts preserved by DHOPE compared with static cold storage. In addition to graft reconditioning, DHOPE may also be used to prolong preservation time, which could facilitate logistics for allocation and transplantation globally.

Methods and analysis

This is a prospective, pseudo-randomised, dual-arm, IDEAL-D (Idea, Development, Exploration, Assessment, Long term study-Framework for Devices) stage 2 clinical device trial designed to determine safety and feasibility of prolonged DHOPE (DHOPE-PRO). The end-time of the donor hepatectomy will determine whether the graft will be assigned to the intervention (16:00–3:59 hour) or to the control arm (4:00–15:59 hour). In total, 36 livers will be included in the study. Livers in the intervention group (n=18) will undergo DHOPE-PRO (≥4 hours) until implantation the following morning, whereas livers in the control group (n=18) will undergo regular DHOPE (2 hours) prior to implantation. The primary endpoint of this study is a composite of the occurrence of all (serious) adverse events during DHOPE and up to 30 days after liver transplantation.

Ethics and dissemination

The protocol was approved by the Medical Ethical Committee of Groningen, METc2020.126 in June 2020, and the study was registered in the Netherlands National Trial Registry (https://www.trialregister.nl/) prior to initiation.

Trial registration number

NL8740.

Minimizing Ischemia Reperfusion Injury in Xenotransplantation

The recent dramatic advances in preventing "initial xenograft dysfunction" in pig-to-non-human primate heart transplantation achieved by minimizing ischemia suggests that ischemia reperfusion injury (IRI) plays an important role in cardiac xenotransplantation. Here we review the molecular, cellular, and immune mechanisms that characterize IRI and associated "primary graft dysfunction" in allotransplantation and consider how they correspond with "xeno-associated" injury mechanisms. Based on this analysis, we describe potential genetic modifications as well as novel technical strategies that may minimize IRI for heart and other organ xenografts and which could facilitate safe and effective clinical xenotransplantation.

Dual Versus Single Oxygenated Hypothermic Machine Perfusion of Porcine Livers: Impact on Hepatobiliary and Endothelial Cell Injury

Supplemental Digital Content is available in the text.

Background.

Hypothermic oxygenated machine perfusion (HOPE) reduces ischemia-reperfusion injury of donor livers and is increasingly used in clinical transplantation. However, it remains unclear whether perfusion via the portal vein alone (HOPE) or via both the portal vein and hepatic artery (dual HOPE or DHOPE) is superior.

Methods.

Twelve porcine livers donated after circulatory death were randomized for 2 h of HOPE (n = 6) or DHOPE (n = 6), followed by 4 h of warm reperfusion with whole blood, to mimic transplantation. Hepatobiliary and endothelial cell function and injury markers were determined in perfusate and bile samples. Biopsies of bile ducts, hepatic arteries, and liver parenchyma were collected to assess histological damage and the expression of endothelial protective genes (KLF-2, eNOS, ET-1, CD31, VWF, VEGF-A).

Results.

There were no differences in hepatobiliary function and injury after warm reperfusion between the groups, apart from a 2-fold lower concentration of alanine aminotransferase in the perfusate (P = 0.045) and a lower peak lactate dehydrogenase in bile (P = 0.04) of livers preserved by DHOPE. Endothelial cell function and injury, as assessed by perfusate nitric oxide and von Willebrand factor antigen levels, as well as endothelial protective gene expressions, were similar between the groups. The hepatic arteries of both groups showed no microscopic evidence of injury.

Conclusions.

This study did not reveal major differences in hepatobiliary or endothelial function and injury after preservation by single or dual HOPE of porcine livers donated after circulatory death.

The Role of Ex Situ Hypothermic Oxygenated Machine Perfusion and Cold Preservation Time in Extended Criteria Donation After Circulatory Death and Donation After Brain Death

Hypothermic oxygenated machine perfusion (HOPE) has the potential to counterbalance the detrimental consequences of cold and warm ischemia time (WIT) in both donation after brain death (DBD) and donation after circulatory death (DCD). Herein we investigated the protective effects of HOPE in extended criteria donor (ECD) DBD and overextended WIT DCD grafts. The present retrospective case series included 50 livers subjected to end-ischemic HOPE or dual DHOPE in 2 liver transplantation (LT) centers from January 2018 to December 2019. All DCD donors were subjected to normothermic regional perfusion before organ procurement. Results are expressed as median (interquartile range [IQR]). In the study period, 21 grafts were derived from overextended WIT DCD donors (total WIT 54 [IQR, 40-60] minutes and 75% classified as futile), whereas 29 were from ECD DBD. A total of 3 biliary complications and 1 case of ischemia-type biliary lesion were diagnosed. The rate of early allograft dysfunction (EAD) was 20%, and those patients had higher Comprehensive Complication Index scores. Through a changing point analysis, cold preservation time >9 hours was associated with prolonged hospital stays (P = 0.02), higher rates of EAD (P = 0.009), and worst post-LT complications (P = 0.02). Logistic regression analyses indicated a significant relationship between cold preservation time and EAD. No differences were shown in terms of the early post-LT results between LTs performed with DCD and DBD. Overall, our data are fully comparable with benchmark criteria in LT. In conclusion, the application of DHOPE obtained satisfactory and promising results using ECD-DBD and overextended DCD grafts. Our findings indicate the need to reduce cold preservation time also in the setting of DHOPE, particularly for grafts showing poor quality.

Hypothermic Oxygenated Machine Perfusion (HOPE) Reduces Early Allograft Injury and Improves Post-Transplant Outcomes in Extended Criteria Donation (ECD) Liver Transplantation from Donation After Brain Death (DBD): Results from a Multicenter Randomized Controlled Trial (HOPE ECD-DBD)

OBJECTIVE

To evaluate peak serum alanine aminotransferase (ALT) and postoperative clinical outcomes after hypothermic oxygenated machine perfusion (HOPE) versus static cold storage (SCS) in extended criteria donation (ECD) liver transplantation (LT) from donation after brain death (DBD).

BACKGROUND

HOPE might improve outcomes in LT, particularly in high-risk settings such as ECD organs after DBD, but this hypothesis has not yet been tested in a randomized controlled clinical trial (RCT).

METHODS

Between 09/2017-09/2020 46 patients undergoing ECD-DBD LT from four centers were randomly assigned to HOPE (n=23) or SCS (n=23). Peak-ALT levels within seven days following LT constituted the primary endpoint. Secondary endpoints included incidence of postoperative complications (Clavien-Dindo classification (CD), Comprehensive Complication Index (CCI)), length of intensive care- (ICU) and hospital-stay, and incidence of early allograft dysfunction (EAD).

RESULTS

Demographics were equally distributed between both groups (donor age: 72 [IQR:59-78] years, recipient age: 62 [IQR:55-65] years, labMELD: 15 [IQR:9-25], 38 male and 8 female recipients). HOPE resulted in a 47% decrease in serum peak ALT (418 [IQR: 221-828] vs. 796 [IQR:477-1195] IU/L, p=0.030), a significant reduction in 90-day complications (44% vs. 74% CD grade ≥3, p=0.036; 32 [IQR:12-56] vs. 52 [IQR:35-98] CCI, p=0.021), and shorter ICU- and hospital-stays (5 [IQR:4-8] vs. 8 [IQR:5-18] days, p=0.045; 20 [IQR:16-27] vs. 36 [IQR:23-62] days, p=0.002) compared to SCS. A trend towards reduced EAD was observed for HOPE (17% vs. 35%; p=0.314).

CONCLUSION

This multicenter RCT demonstrates that HOPE, in comparison to SCS, significantly reduces early allograft injury and improves post-transplant outcomes in ECD-DBD liver transplantation.

Clinical value and limitations of the preoperative C-reactive-protein-to-albumin ratio in predicting post-operative morbidity and mortality after deceased-donor liver transplantation: a retrospective single-centre study

Liver transplantation is still associated with a high risk of severe complications and post-operative mortality. This study examines the predictive value of the preoperative C-reactive-protein-to-albumin ratio (CAR) regarding perioperative morbidity and mortality in deceased-donor liver transplantation (DDLT) recipients. In total, 390 DDLT recipients between 05/2010 and 03/2020 were eligible. Predictive abilities of CAR were examined through receiver operating characteristic curve (ROC) analyses. Groups were compared using parametric and non-parametric tests as appropriate. Independent risk factors for morbidity and mortality were identified using uni- and multivariable logistic regression analyses. A good predictive ability for CAR was shown regarding perioperative morbidity (comprehensive complication index ≥75, Clavien-Dindo score ≥4a) and 12-month mortality, with an ideal cut-off of CAR = 26%. Patients with CAR>26% had significantly higher median CCI scores (60 vs. 43, P < 0.001), longer intensive care unit (ICU, 5 vs. 4 days, P < 0.001) and hospital (28 vs. 21 days, P < 0.001) stays and higher 12-month mortality rates (20% vs 6%, P < 0.001). Multivariable analyses identified CAR>26%, pre-OLT inpatient hospitalization (including ICU) and post-operative red blood cell transfusions as independent predictors of severe cumulative morbidity (CCI≥75). Preoperative CAR might be a reliable additional tool to predict perioperative morbidity and mortality in DDLT recipients.

Various myosteatosis selection criteria and their value in the assessment of short- and long-term outcomes following liver transplantation

Body composition and myosteatosis affect clinical outcomes in orthotopic liver transplantation (OLT). Here we aimed to compare the value and limitations of various selection criteria to define pre-transplant myosteatosis in the assessment of short- and long-term outcomes following OLT. We retrospectively analyzed the data of 264 consecutive recipients who underwent deceased donor OLT at a German university medical centre. Myosteatosis was evaluated by preoperative computed-tomography-based segmentation. Patients were stratified using muscle radiation attenuation of the whole muscle area (L3Muslce-RA), psoas RA (L3Psoas-RA) and intramuscular adipose tissue content (IMAC) values. L3Muslce-RA, L3Psoas-RA and IMAC performed well without major differences and identified patients at risk for inferior outcomes in the group analysis. Quartile-based analyses, receiver operating characteristic curve and correlation analyses showed a superior association of L3Muslce-RA with perioperative outcomes when compared to L3Psoas-RA and L3IMAC. Long-term outcome did not show any major differences between the used selection criteria. This study confirms the prognostic role of myosteatosis in OLT with a particularly strong value in the perioperative phase. Although, based on our data, L3Muscle-RA might be the most suitable and recommended selection criterion to assess CT-based myosteatosis when compared to L3Psoas-RA and L3IMAC, further studies are warranted to validate these findings.

In Situ Vaccination as a Strategy to Modulate the Immune Microenvironment of Hepatocellular Carcinoma

Hepatocellular Carcinoma (HCC) is a highly prevalent malignancy that develops in patients with chronic liver diseases and dysregulated systemic and hepatic immunity. The tumor microenvironment (TME) contains tumor-associated macrophages (TAM), cancer-associated fibroblasts (CAF), regulatory T cells (Treg) and myeloid-derived suppressor cells (MDSC) and is central to mediating immune evasion and resistance to therapy. The interplay between these cells types often leads to insufficient antigen presentation, preventing effective anti-tumor immune responses. In situ vaccines harness the tumor as the source of antigens and implement sequential immunomodulation to generate systemic and lasting antitumor immunity. Thus, in situ vaccines hold the promise to induce a switch from an immunosuppressive environment where HCC cells evade antigen presentation and suppress T cell responses towards an immunostimulatory environment enriched for activated cytotoxic cells. Pivotal steps of in situ vaccination include the induction of immunogenic cell death of tumor cells, a recruitment of antigen-presenting cells with a focus on dendritic cells, their loading and maturation and a subsequent cross-priming of CD8+ T cells to ensure cytotoxic activity against tumor cells. Several in situ vaccine approaches have been suggested, with vaccine regimens including oncolytic viruses, Flt3L, GM-CSF and TLR agonists. Moreover, combinations with checkpoint inhibitors have been suggested in HCC and other tumor entities. This review will give an overview of various in situ vaccine strategies for HCC, highlighting the potentials and pitfalls of in situ vaccines to treat liver cancer.

Risk factors and impact of early anastomotic biliary complications after liver transplantation: UK registry analysis

Background

Biliary leaks and anastomotic strictures are common early anastomotic biliary complications (EABCs) following liver transplantation. However, there are no large multicentre studies investigating their clinical impact or risk factors. This study aimed to define the incidence, risk factors and impact of EABC.

Methods

The NHS registry on adult liver transplantation between 2006 and 2017 was reviewed retrospectively. Adjusted regression models were used to assess predictors of EABC, and their impact on outcomes.

Results

Analyses included 8304 liver transplant recipients. Patients with EABC (9·6 per cent) had prolonged hospitalization (23 versus 15 days; P < 0·001) and increased chance for readmission within the first year (56 versus 32 per cent; P < 0·001). Patients with EABC had decreased estimated 5-year graft survival of 75·1 versus 84·5 per cent in those without EABC, and decreased 5-year patient survival of 76·9 versus 83·3 per cent; both P < 0.001. Adjusted Cox regression revealed that EABCs have a significant and independent impact on graft survival (leak hazard ratio (HR) 1·344, P = 0·015; stricture HR 1·513, P = 0·002; leak plus stricture HR 1·526, P = 0·036) and patient survival (leak HR 1·215, P = 0·136, stricture HR 1·526, P = 0·001; leak plus stricture HR 1·509; P = 0·043). On adjusted logistic regression, risk factors for EABC included donation after circulatory death grafts, graft aberrant arterial anatomy, biliary anastomosis type, vascular anastomosis time and recipient model of end-stage liver disease.

Conclusion

EABCs prolong hospital stay, increase readmission rates and are independent risk factors for graft loss and increased mortality. This study has identified factors that increase the likelihood of EABC occurrence; research into interventions to prevent EABCs in these at-risk groups is vital to improve liver transplantation outcomes.

Ex-situ liver preservation with machine preservation

PURPOSE OF REVIEW

To summarize key studies in liver preservation published over the last 3 years and evaluate benefits and limitations of the different perfusion techniques. Selected experimental applications that may be translated to the clinical use will be also discussed.

RECENT FINDINGS

Normothermic machine perfusion (NMP) has transitioned into clinical practice. Viability assessment is a reliable tool for clinical decision-making, and safety of the back-to-base approach has facilitated adoption of the technology. Data supporting well tolerated use of declined livers after NMP and new protocols selecting complex recipients aim to improve access to suitable organs. Hypothermic machine perfusion (HMP) is showing promising clinical results by decreasing biliary complications in recipients' receiving organs donated after circulatory death (DCD) and improving early graft function in extended criteria organs. Long-term data of HMP on DCD livers shows improved graft survival over standard SCS. Novel approaches utilizing sequential HMP--NMP or ischaemia-free preservation aim to improve outcomes of extended criteria organs.

SUMMARY

Machine perfusion for organ transplantation has become an established technique but the field is rapidly evolving. Ongoing research focuses on evaluation of the intervention efficacy and finding optimal indications to use each perfusion strategy according to graft type and clinical scenario.

Design, Analysis, and Pitfalls of Clinical Trials Using Ex Situ Liver Machine Perfusion: The International Liver Transplantation Society Consensus Guidelines

BACKGROUND

Recent trials in liver machine perfusion (MP) have revealed unique challenges beyond those seen in most clinical studies. Correct trial design and interpretation of data are essential to avoid drawing conclusions that may compromise patient safety and increase costs.

METHODS

The International Liver Transplantation Society, through the Special Interest Group "DCD, Preservation and Machine Perfusion," established a working group to write consensus statements and guidelines on how future clinical trials in liver perfusion should be designed, with particular focus on relevant clinical endpoints and how different techniques of liver perfusion should be compared. Protocols, abstracts, and full published papers of clinical trials using liver MP were reviewed. The use of a simplified Grading of Recommendations Assessment, Development, and Evaluation working group (GRADE) system was attempted to assess the level of evidence. The working group presented its conclusions at the International Liver Transplantation Society consensus conference "DCD, Liver Preservation, and Machine Perfusion" held in Venice, Italy, on January 31, 2020.

RESULTS

Twelve recommendations were proposed with the main conclusions that clinical trials investigating the effect of MP in liver transplantation should (1) make the protocol publicly available before the start of the trial, (2) be adequately powered, and (3) carefully consider timing of randomization in function of the primary outcome.

CONCLUSIONS

There are issues with using accepted primary outcomes of liver transplantation trials in the context of MP trials, and no ideal endpoint could be defined by the working group. The setup of an international registry was considered vital by the working group.

The role of recipient myosteatosis in graft and patient survival after deceased donor liver transplantation

BACKGROUND

Myosteatosis is associated with perioperative outcomes in orthotopic liver transplantation (OLT). Here, we investigated the effects of body composition and myosteatosis on long-term graft and patient survival following OLT.

METHODS

Clinical data from 225 consecutive OLT recipients from a prospective database were retrospectively analysed (May 2010 to December 2017). Computed tomography-based lumbar skeletal muscle index (SMI) (muscle mass) and mean skeletal muscle radiation attenuation (SM-RA) (myosteatosis) were calculated using a segmentation tool (3D Slicer). Patients with low skeletal muscle mass (low SMI) and myosteatosis (low SM-RA) were identified using predefined and validated cut-off values.

RESULTS

The mean donor and recipient age was 55 ± 16 and 54 ± 12 years, respectively. Some 67% of the recipients were male. The probability of graft and patient survival was significantly lower in patients with myosteatosis compared with patients with higher SM-RA values (P = 0.011 and P = 0.001, respectively). Low skeletal muscle mass alone was not associated with graft and patient survival (P = 0.273 and P = 0.278, respectively). Dividing the cohort into quartiles, based on the values of SMI and SM-RA, resulted in significant differences in patient but not in graft survival (P = 0.011). Even though multivariable analysis identified low SM-RA as an important prognostic marker (hazard ratio: 2.260, 95% confidence interval: 1.177-4.340, P = 0.014), myosteatosis lost its significance when early mortality (90 days) was excluded from the final multivariable model. Patients with myosteatosis showed significantly higher all-cause mortality and in particular higher rates of deaths due to respiratory and septic complication (P = 0.002, P = 0.022, and P = 0.049, respectively).

CONCLUSIONS

Preoperative myosteatosis may be an important prognostic marker in patients undergoing deceased donor liver transplantation. The prognostic value of myosteatosis seems to be particularly important in the early post-operative phase. Validation in prospective clinical trials is warranted.

[Machine Perfusion for Liver Transplantation - What is Possible and Where Do We Stand in Germany? Review of the Literature and Results of a National Survey]

Machine perfusion of donor livers is currently regarded as the most important innovation in transplant surgery to address the continuing shortage of organs in liver transplantation. Hypothermic machine perfusion (HMP) is safe to use and appears to reduce the risk of biliary complications and improve the long-term survival of transplanted organs following preservation by cold static storage - even in donors after cardiac death. A potential functional test of donor organs during HMP uses flavin mononucleotide and is still under clinical investigation. Normothermic machine perfusion (NMP) has a greater risk of technical problems, but functional testing using conventional laboratory parameters during NMP allows significant expansion of the donor pool, even though no prospective randomised study has been able to demonstrate a survival advantage for transplanted organs after NMP. In addition, the preservation time of the donor organs can be significantly extended with the help of NMP, which is particularly advantageous for complex recipient operations and/or logistics. Both methods could be applied for various scenarios in transplantation medicine - theoretically also in combination. The majority of German transplant centres regard machine perfusion as an important innovation and already actively perform perfusions or are in preparation for doing so. However, the overall practical experience in Germany is still relatively low, with only 2 centres having performed more than 20 perfusions. In the coming years, multi-centre efforts to conduct clinical trials and to develop national guidelines on machine perfusion will therefore be indispensable in order to define the potential of these technological developments objectively and to exploit it optimally for the field of transplantation medicine.

"Complimenting the Complement": Mechanistic Insights and Opportunities for Therapeutics in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and a leading cause of death in the US and worldwide. HCC remains a global health problem and is highly aggressive with unfavorable prognosis. Even with surgical interventions and newer medical treatment regimens, patients with HCC have poor survival rates. These limited therapeutic strategies and mechanistic understandings of HCC immunopathogenesis urgently warrant non-palliative treatment measures. Irrespective of the multitude etiologies, the liver microenvironment in HCC is intricately associated with chronic necroinflammation, progressive fibrosis, and cirrhosis as precedent events along with dysregulated innate and adaptive immune responses. Central to these immunological networks is the complement cascade (CC), a fundamental defense system inherent to the liver which tightly regulates humoral and cellular responses to noxious stimuli. Importantly, the liver is the primary source for biosynthesis of >80% of complement components and expresses a variety of complement receptors. Recent studies implicate the complement system in liver inflammation, abnormal regenerative responses, fibrosis, carcinogenesis, and development of HCC. Although complement activation differentially promotes immunosuppressive, stimulant, and angiogenic microenvironments conducive to HCC development, it remains under-investigated. Here, we review derangement of specific complement proteins in HCC in the context of altered complement regulatory factors, immune-activating components, and their implications in disease pathogenesis. We also summarize how complement molecules regulate cancer stem cells (CSCs), interact with complement-coagulation cascades, and provide therapeutic opportunities for targeted intervention in HCC.

Evaluation of the ex vivo liver viability using a nuclear magnetic resonance relaxation time-based assay in a porcine machine perfusion model

There is a dearth of effective parameters for selecting potentially transplantable liver grafts from expanded-criteria donors. In this study, we used a nuclear magnetic resonance (NMR) relaxation analyzer-based assay to assess the viability of ex vivo livers obtained via porcine donation after circulatory death (DCD). Ex situ normothermic machine perfusion (NMP) was utilized as a platform for viability test of porcine DCD donor livers. A liver-targeted contrast agent, gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid (Gd-EOB-DTPA), was injected into the perfusate during NMP, and the dynamic biliary excretion of the Gd-EOB-DTPA was monitored by measuring the longitudinal relaxation time (T1). The longitudinal relaxation rate (R1) of the bile was served as a parameter. The delay of increase in biliary R1 during early stage of NMP indicated the impaired function of liver grafts in both warm and cold ischemia injury, which was correlated with the change of alanine aminotransferase. The preservative superiority in cold ischemia of dual hypothermic oxygenated machine perfusion could also be verified by assessing biliary R1 and other biochemical parameters. This study allows for the dynamic assessment of the viability of porcine DCD donor livers by combined usage of ex situ NMP and NMR relaxation time based assay, which lays a foundation for further clinical application.

Hemorheological and Microcirculatory Factors in Liver Ischemia-Reperfusion Injury-An Update on Pathophysiology, Molecular Mechanisms and Protective Strategies

Hepatic ischemia-reperfusion injury (IRI) is a multifactorial phenomenon which has been associated with adverse clinical outcomes. IRI related tissue damage is characterized by various chronological events depending on the experimental model or clinical setting. Despite the fact that IRI research has been in the spotlight of scientific interest for over three decades with a significant and continuous increase in publication activity over the years and the large number of pharmacological and surgical therapeutic attempts introduced, not many of these strategies have made their way into everyday clinical practice. Furthermore, the pathomechanism of hepatic IRI has not been fully elucidated yet. In the complex process of the IRI, flow properties of blood are not neglectable. Hemorheological factors play an important role in determining tissue perfusion and orchestrating mechanical shear stress-dependent endothelial functions. Antioxidant and anti-inflammatory agents, ischemic conditioning protocols, dynamic organ preservation techniques may improve rheological properties of the post-reperfusion hepatic blood flow and target endothelial cells, exerting a potent protection against hepatic IRI. In this review paper we give a comprehensive overview of microcirculatory, rheological and molecular–pathophysiological aspects of hepatic circulation in the context of IRI and hepatoprotective approaches.

Intraoperative Transfusion of Fresh Frozen Plasma Predicts Morbidity Following Partial Liver Resection for Hepatocellular Carcinoma

BACKGROUND

The reduction of perioperative morbidity is a main surgical goal in patients undergoing partial hepatectomy for hepatocellular carcinoma (HCC). Here, we investigated clinical determinants of perioperative morbidity in a European cohort of patients undergoing surgical resection for HCC.

METHODS

A total 136 patients who underwent partial hepatectomy for HCC between 2011 and 2017 at our institution were included in this analysis. The associations between major surgical complications (Clavien-Dindo ≥ 3) and overall morbidity (Clavien-Dindo ≥ 1) with clinical variables were assessed using univariate and multivariable binary logistic regression analysis.

RESULTS

Multivariable analysis identified the Child-Pugh-Score (CPS, HR = 3.23; p = 0.040), operative time (HR = 5.63; p = 0.003), and intraoperatively administered fresh frozen plasma (FFP, HR = 5.62; p = 0.001) as independent prognostic markers of major surgical complications, while only FFP (HR = 6.52; p = 0.001) was associated with morbidity in the multivariable analysis. The transfusion of FFP was not associated with perioperative liver functions tests.

CONCLUSIONS

The intraoperative administration of FFP is an important independent predictor of perioperative morbidity in patients undergoing partial hepatectomy for HCC.

Impact of Angiogenesis- and Hypoxia-Associated Polymorphisms on Tumor Recurrence in Patients with Hepatocellular Carcinoma Undergoing Surgical Resection

Simple Summary

Hepatocellular carcinoma remains a leading cause of cancer-related death and the most common primary hepatic malignancy in the Western hemisphere. Previous research found that angiogenesis-related cytokines and elevated levels of interleukin 8 and vascular endothelial growth factor (VEGF) shorten the expected time of survival. Moreover, factors of tumor angiogenesis- and hypoxia-driven signaling pathways are already associated with worse outcome in disease-free survival in several tumor entities. Our study investigates the prognosis of hepatocellular carcinoma patients based on a selection of ten different single-nucleotide polymorphisms from angiogenesis, carcinogenesis, and hypoxia pathways. Our study with 127 patients found supporting evidence that polymorphisms in angiogenesis-associated pathways corelate with disease-free survival and clinical outcome in patients with hepatocellular carcinoma.

Abstract

Tumor angiogenesis plays a pivotal role in hepatocellular carcinoma (HCC) biology. Identifying molecular prognostic markers is critical to further improve treatment selection in these patients. The present study analyzed a subset of 10 germline polymorphisms involved in tumor angiogenesis pathways and their impact on prognosis in HCC patients undergoing partial hepatectomy in a curative intent. Formalin-fixed paraffin-embedded (FFPE) tissues were obtained from 127 HCC patients at a German primary care hospital. Genomic DNA was extracted, and genotyping was carried out using polymerase chain reaction (PCR)–restriction fragment length polymorphism-based protocols. Polymorphisms in interleukin-8 (IL-8) (rs4073; p = 0.047, log-rank test) and vascular endothelial growth factor (VEGF C + 936T) (rs3025039; p = 0.045, log-rank test) were significantly associated with disease-free survival (DFS). After adjusting for covariates in the multivariable model, IL-8 T-251A (rs4073) (adjusted p = 0.010) and a combination of “high-expression” variants of rs4073 and rs3025039 (adjusted p = 0.034) remained significantly associated with DFS. High-expression variants of IL-8 T-251A may serve as an independent molecular marker of prognosis in patients undergoing surgical resection for HCC. Assessment of the patients’ individual genetic risks may help to identify patient subgroups at high risk for recurrence following curative-intent surgery.

Review: Ischemia Reperfusion Injury-A Translational Perspective in Organ Transplantation

Thanks to the development of new, more potent and selective immunosuppressive drugs together with advances in surgical techniques, organ transplantation has emerged from an experimental surgery over fifty years ago to being the treatment of choice for many end-stage organ diseases, with over 139,000 organ transplants performed worldwide in 2019. Inherent to the transplantation procedure is the fact that the donor organ is subjected to blood flow cessation and ischemia during harvesting, which is followed by preservation and reperfusion of the organ once transplanted into the recipient. Consequently, ischemia/reperfusion induces a significant injury to the graft with activation of the immune response in the recipient and deleterious effect on the graft. The purpose of this review is to discuss and shed new light on the pathways involved in ischemia/reperfusion injury (IRI) that act at different stages during the donation process, surgery, and immediate post-transplant period. Here, we present strategies that combine various treatments targeted at different mechanistic pathways during several time points to prevent graft loss secondary to the inflammation caused by IRI.

Association of Perfusion Characteristics and Posttransplant Liver Function in Ischemia-Free Liver Transplantation

It has been shown that normothermic machine perfusion (NMP), a novel preservation method, is able to assess and resuscitate liver grafts with risk factors. However, there is no consistent criteria for the assessment of liver grafts with NMP. Ischemia-free liver transplantation (IFLT) includes innovative surgical techniques and NMP, which can protect liver grafts from ischemia throughout organ procurement, preservation, and implantation. In our center, 28 human livers from donation after brain death donors were subjected to IFLT between July 2017 and October 2018. The correlation between posttransplant liver function tests with the perfusion parameters, blood gas analysis of perfusate, and bile biochemistry were analyzed. During the preservation phase, the vascular flow was stable, and the lactate level decreased rapidly. The transaminase release in the perfusate was low but stable, whereas the glucose level remained high. The perfusate lactate and aspartate aminotransferase (AST) levels at 1 hour of perfusion were correlated with the posttransplant peak AST level. There were negative correlations between the portal vein and hepatic artery flows at the end of perfusion and the peak transaminase levels within 7 days after transplantation. In conclusion, during IFLT, NMP is able to bridge the liver grafts from donors to recipients and can allow the assessment of liver function by perfusion characteristics.

Decrease of renal resistance during hypothermic oxygenated machine perfusion is associated with early allograft function in extended criteria donation kidney transplantation

Hypothermic oxygenated machine perfusion (HOPE) was recently tested in preclinical trials in kidney transplantation (KT). Here we investigate the effects of HOPE on extended-criteria-donation (ECD) kidney allografts (KA). Fifteen ECD-KA were submitted to 152 ± 92 min of end-ischemic HOPE and were compared to a matched group undergoing conventional-cold-storage (CCS) KT (n = 30). Primary (delayed graft function-DGF) and secondary (e.g. postoperative complications, perfusion parameters) endpoints were analyzed within 6-months follow-up. There was no difference in the development of DGF between the HOPE and CCS groups (53% vs. 33%, respectively; p = 0.197). Serum urea was lower following HOPE compared to CCS (p = 0.003), whereas the CCS group displayed lower serum creatinine and higher eGFR rates on postoperative days (POD) 7 and 14. The relative decrease of renal vascular resistance (RR) following HOPE showed a significant inverse association with serum creatinine on POD1 (r = − 0.682; p = 0.006) as well as with serum urea and eGFR. Besides, the relative RR decrease was more prominent in KA with primary function when compared to KA with DGF (p = 0.013). Here we provide clinical evidence on HOPE in ECD-KT after brain death donation. Relative RR may be a useful predictive marker for KA function. Further validation in randomized controlled trials is warranted.

Trial registration: clinicaltrials.gov (NCT03378817, Date of first registration: 20/12/2017).

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.

Low Postoperative Platelet Counts Are Associated with Major Morbidity and Inferior Survival in Adult Recipients of Orthotopic Liver Transplantation

BACKGROUND

Platelets (PLT) play an essential functional role in cellular injury and liver regeneration following partial hepatectomy and orthotopic liver transplantation (OLT). Here, we investigated the association of postoperative PLT counts with short- and long-term outcomes in adult OLT recipients.

METHODS

Three hundred consecutive patients from our prospective OLT database were analyzed retrospectively (May 2010-November 2017). Ninety-day post-OLT complications were graded using the Clavien-Dindo (CD) classification and quantified by the comprehensive complication index (CCI). To determine the prognostic accuracy of PLT counts, the area under the receiver operating characteristic curve (AUROC) was calculated for major complications (CD ≥ 3b). Parametric and non-parametric tests were applied for subgroup analyses. Uni- and multivariable logistic regression analyses were performed to identify risk factors for major complications. Graft and patient survival were analyzed using the Kaplan-Meier method as well as uni- and multivariable Cox regression analyses.

RESULTS

Postoperative day 6 PLT counts < 70 × 10⁹/L (POD6-70) were identified as the best cutoff for predicting major complications (AUROC = 0.7; p < 0.001; Youden index 0.317). The stratification of patients into low- (n = 113) and high-PLT (n = 187) groups highlighted significant differences in major complications (CCI 68 ± 29 vs. 43 ± 28, p < 0.001); length of hospital and intensive care unit (ICU) stay (53 ± 43 vs. 31 ± 25, p < 0.001; 21 ± 29 vs. 7 ± 11, p < 0.001, respectively) and estimated procedural costs. POD6-70 was associated with inferior 5-year graft survival. Multivariable logistic regression analysis identified POD6-70 as an independent predictor of major complications (odds ratio 2.298, confidence intervals 1.179-4.478, p = 0.015).

CONCLUSION

In OLT patients, a PLT count on POD6 of less than 70 × 10⁹/L bears a prognostic significance warranting further investigations.

Ischemia-Reperfusion Injury in Marginal Liver Grafts and the Role of Hypothermic Machine Perfusion: Molecular Mechanisms and Clinical Implications

Ischemia-reperfusion injury (IRI) constitutes a significant source of morbidity and mortality after orthotopic liver transplantation (OLT). The allograft is metabolically impaired during warm and cold ischemia and is further damaged by a paradox reperfusion injury after revascularization and reoxygenation. Short-term and long-term complications including post-reperfusion syndrome, delayed graft function, and immune activation have been associated with IRI. Due to the current critical organ shortage, extended criteria grafts are increasingly considered for transplantation, however, with an elevated risk to develop significant features of IRI. In recent years, ex vivo machine perfusion (MP) of the donor liver has witnessed significant advancements. Here, we describe the concept of hypothermic (oxygenated) machine perfusion (HMP/HOPE) approaches and highlight which allografts may benefit from this technology. This review also summarizes clinical applications and the main aspects of ongoing randomized controlled trials on hypothermic perfusion. The mechanistic aspects of IRI and hypothermic MP-which include tissue energy replenishment, optimization of mitochondrial function, and the reduction of oxidative and inflammatory damage following reperfusion-will be comprehensively discussed within the context of current preclinical and clinical evidence. Finally, we highlight novel trends and future perspectives in the field of hypothermic MP in the context of recent findings of basic and translational research.

Therapeutics administered during ex vivo liver machine perfusion: An overview

Although the use of extended criteria donors has increased the pool of available livers for transplant, it has also introduced the need to develop improved methods of protection against ischemia-reperfusion injury (IRI), as these "marginal" organs are particularly vulnerable to IRI during the process of procurement, preservation, surgery, and post-transplantation. In this review, we explore the current basic science research investigating therapeutics administered during ex vivo liver machine perfusion aimed at mitigating the effects of IRI in the liver transplantation process. These various categories of therapeutics are utilized during the perfusion process and include invoking the RNA interference pathway, utilizing defatting cocktails, and administering classes of agents such as vasodilators, anti-inflammatory drugs, human liver stem cell-derived extracellular vesicles, and δ-opioid agonists in order to reduce the damage of IRI. Ex vivo machine perfusion is an attractive alternative to static cold storage due to its ability to continuously perfuse the organ, effectively deliver substrates and oxygen required for cellular metabolism, therapeutically administer pharmacological or cytoprotective agents, and continuously monitor organ viability during perfusion. The use of administered therapeutics during machine liver perfusion has demonstrated promising results in basic science studies. While novel therapeutic approaches to combat IRI are being developed through basic science research, their use in clinical medicine and treatment in patients for liver transplantation has yet to be explored.

Hypothermic Oxygenated Machine Perfusion of Extended Criteria Kidney Allografts from Brain Dead Donors: Protocol for a Prospective Pilot Study

Background

Kidney transplantation is the only curative treatment option for end-stage renal disease. The unavailability of adequate organs for transplantation has resulted in a substantial organ shortage. As such, kidney donor allografts that would have previously been deemed unsuitable for transplantation have become an essential organ pool of extended criteria donor allografts that are now routinely being transplanted on a global scale. However, these extended criteria donor allografts are associated with significant graft-related complications. As a result, hypothermic oxygenated machine perfusion (HOPE) has emerged as a powerful, novel technique in organ preservation, and it has recently been tested in preclinical trials in kidney transplantation. In addition, HOPE has already provided promising results in a few clinical series of liver transplantations where the liver was donated after cardiac death.

Objective

The present trial is an investigator-initiated prospective pilot study on the effects of HOPE on extended criteria donor allografts donated after brain death and used in kidney transplantation.

Methods

A total of 15 kidney allografts with defined inclusion/exclusion criteria will be submitted to two hours of HOPE via the renal artery before implantation, and are going to be compared to a case-matched group of 30 patients (1:2 matching) who had kidneys transplanted after conventional cold storage. Primary (posttransplant dialysis within 7 days) and secondary (postoperative complications, early graft function, duration of hospital and intensive care unit stay, and six-month graft survival) endpoints will be analyzed within a six-month follow-up period. The extent of ischemia-reperfusion injury will be assessed using kidney tissue, perfusate, and serum samples taken during the perioperative phase of kidney transplantation

Results

The results of this trial are expected in the first quarter of 2020 and will be presented at national and international scientific meetings and published in international peer-reviewed medical journals. The trial was funded in the third quarter of 2017 and patient enrollment is currently ongoing.

Conclusions

This prospective study is designed to explore the effects of HOPE on extended criteria donor kidney allografts donated after brain death. The present report represents the preresults phase.

Trial Registration

Clinicaltrials.gov NCT03378817; https://clinicaltrials.gov/ct2/show/NCT03378817

A Dual Protective Effect of Intestinal Remote Ischemic Conditioning in a Rat Model of Total Hepatic Ischemia

The present study aimed to investigate the effects of intestinal remote ischemic preconditioning (iRIC) on ischemia-reperfusion injury (IRI) and gut barrier integrity in a rat model of total hepatic ischemia (THI). Male Wistar rats (n = 50; 250–300 g) were randomly allocated into two experimental groups: RIC/Control. Thirty minutes of THI was induced by clamping the hepatoduodenal ligament. iRIC was applied as 4-min of ischemia followed by 11-min of reperfusion by clamping the superior mesenteric artery. Animals were sacrificed at 1, 2, 6, 24 h post-reperfusion (n = 5/group/timepoint). RIC of the gut significantly improved microcirculation of the ileum and the liver. Tissue ATP-levels were higher following iRIC (Liver: 1.34 ± 0.12 vs. 0.97 ± 0.20 μmol/g, p = 0.04) and hepatocellular injury was reduced significantly (ALT: 2409 ± 447 vs. 6613 ± 1117 IU/L, p = 0.003). Systemic- and portal venous IL-6 and TNF-alpha levels were markedly lower following iRIC, demonstrating a reduced inflammatory response. iRIC led to a structural and functional preservation of the intestinal barrier. These results suggest that iRIC might confer a potent protection against the detrimental effects of THI in rats via reducing IRI and systemic inflammatory responses and at the same time by mitigating the dramatic consequences of severe intestinal congestion and bacterial translocation.

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.