Normothermic machine perfusion (NMP) has emerged as an innovative organ preservation technique. Developing an understanding for the donor organ immune cell composition and its dynamic changes during NMP is essential. We aimed for a comprehensive characterization of immune cell (sub)populations, cell trafficking and cytokine release during liver NMP. Single-cell transcriptome profiling of human donor livers prior to, during NMP and after transplantation shows an abundance of CXC chemokine receptor 1⁺/2⁺ (CXCR1⁺/CXCR2⁺) neutrophils, which significantly decreased during NMP. This is paralleled by a large efflux of passenger leukocytes with neutrophil predominance in the perfusate. During NMP, neutrophils shift from a pro-inflammatory state towards an aged/chronically activated/exhausted phenotype, while anti-inflammatory/tolerogenic monocytes/macrophages are increased. We herein describe the dynamics of the immune cell repertoire, phenotypic immune cell shifts and a dominance of neutrophils during liver NMP, which potentially contribute to the inflammatory response. Our findings may serve as resource to initiate future immune-interventional studies.

Background and Aims: Immune checkpoint inhibitors (ICIs) are increasingly used in patients with advanced HCC patients awaiting liver transplantation (LT). However, concerns about the risk of posttransplant rejection persist. Approach and Results: We conducted an international retrospective cohort study including 119 HCC patients who received ICIs prior to LT. We analyzed the incidence of allograft rejection, graft loss, and posttransplant recurrence with a particular focus on the washout period between the last ICI dose and LT. In this study, 24 of the 119 (20.2%) patients experienced allograft rejection with a median time to rejection of 9 days (IQR 6–10) post-LT. A linear relationship was observed between shorter washout periods and higher rejection risk. Washout periods <30 days (OR: 21.3, 95% CI: 5.93–103, p<0.001) and between 30 and 50 days (OR: 9.48, 95% CI 2.47–46.8, p=0.002) were significantly associated with higher rejection rates in the univariate analysis compared to the washout period above 50 days. Graft loss as a result of rejection occurred in 6 patients (25%) with rejection. No factors related to grafts were associated with rejection. A longer washout period was not associated with a lower recurrence-free survival posttransplantation at 36 months (71% vs. 67%, p=0.71). Conclusions: Our findings suggest that a washout period longer than 50 days for ICIs before LT appears to be safe with respect to rejection risk. While these results may help guide clinical decision-making, future prospective studies are essential to establish definitive guidelines.

Liver transplantation (LT) was originally described by Starzl as a promising strategy to treat primary malignancies of the liver. Confronted with high recurrence rates, indications drifted towards non-oncologic liver diseases with LT finally evolving from a high-risk surgery to an almost routine surgical procedure. Continuously improving outcomes following LT and evolving oncological treatment strategies have driven renewed interest in transplant oncology. This is not only reflected by constant refinements to the criteria for LT in patients with HCC, but especially by efforts to expand indications to other primary and secondary liver malignancies. With new patient-centred oncological treatments on the rise and new technologies to expand the donor pool, the field has the chance to come full circle. In this review, we focus on the concept of transplant oncology, current indications, as well as technical and ethical aspects in the context of donor organs as precious resources.

Objective: To report outcomes from routine clinical practice of liver transplantation (LT) following normothermic liver machine perfusion (NLMP) and compare to LT after static cold storage (SCS). Background: NLMP is emerging as a clinical routine in LT and has recently received renewed attention; however, outcomes outside of clinical trials are lacking. Methods: All adult LT between February 2018 and January 2023 were included. A comprehensive viability assessment was applied during NLMP. Outcomes were compared between NLMP and SCS recipients, as well as benchmark and non-benchmark cases. Results: Of the 332 LT included, 174 underwent NLMP and 158 were transplanted after SCS. Sixty-seven organs were accepted and transplanted only under the premise of NLMP. One-year graft survival for SCS and NLMP recipients was 83.8% versus 81.3% and 93.4% for benchmark cases in the overall cohort. Total preservation time had no influence on graft survival in the NLMP group but was associated with inferior 1-year graft survival in the SCS group. NLMP usage increased significantly over the duration of the study period, as did the median total preservation time. With increasing NLMP use and longer preservation times, nighttime surgery decreased significantly from 41.9% to 4.2%. Conclusions: Prolonged preservation times ease logistics and enable daytime surgery. The possibility of NLMP offers to expand LT without negatively affecting outcomes.

Introduction: Liver transplantation (LT) is potentially curative for patients with cirrhosis and hepatocellular carcinoma (HCC). However, this procedure is usually reserved for patients with early tumor stages or after successful downstaging with local regional therapies. In patients with locally advanced HCC, current guidelines recommend locoregional and palliative systemic therapies for tumor stages Barcelona Clinic Liver Cancer (BCLC) B and C, respectively. Case Report: In this article, we describe a 63-year-old male patient with locally advanced HCC (BCLC C) and hepatitis C-associated cirrhosis. Following systemic treatment with the immune checkpoint inhibitor atezolizumab and the anti-VEGF antibody bevacizumab, significant downstaging to a tumor stage within the Milan criteria was achieved after which LT was successfully performed. Conclusion: As more effective systemic therapies become available, LT and potential curative treatment could become feasible for selected patients with locally advanced HCC.

Biliary tract cancer (BTC) comprises a clinically diverse and genetically heterogeneous group of tumors along the intra- and extrahepatic biliary system (intrahepatic and extrahepatic cholangiocarcinoma) and gallbladder cancer with the common feature of a poor prognosis, despite increasing molecular knowledge of associated genetic aberrations and possible targeted therapies. Therefore, the search for even more precise and individualized therapies is ongoing and preclinical tumor models are central to the development of such new approaches. The models described in the current review include simple and advanced in vitro and in vivo models, including cell lines, 2D monolayer, spheroid and organoid cultures, 3D bioprinting, patient-derived xenografts, and more recently, machine-perfusion platform-based models of resected liver specimens. All these models have individual advantages, disadvantages and limitations that need to be considered depending on the desired application. In addition to potential cost limitations, availability of BTC cell types, time required for model establishment and growth success rate, the individual models differently reflect relevant characteristics such as tumor heterogeneity, spatial tumor-stroma microenvironment interactions, metabolic and nutritional gradients and immunological interactions. Therefore, a consequent combination of different models may be required to improve clinical study outcomes by strengthening the preclinical data basis.