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

Revolution in Organ Preservation: Technological Exploration

Organ preservation plays a critical role in addressing transplantation challenges, including donor shortages and ischemia-reperfusion injury (IRI). Continuous advancements in preservation technologies are essential to meet the increasing demand for transplantable organs. This review provides a comprehensive analysis of organ preservation techniques, spanning from hypothermic storage to advanced methods such as supercooling, vitrification, and partial freezing. Historical milestones, including the development of the EuroCollins, University of Wisconsin (UW), ET-Kyoto, and Celsior solutions, are discussed alongside innovations in machine perfusion and cryopreservation technologies. Particular emphasis is placed on the underlying mechanisms of these techniques, such as metabolic rate suppression, prevention of ice crystal formation, and the application of cryoprotectants, all aimed at extending preservation duration and improving organ quality. Emerging trends, such as the integration of nanotechnology and artificial organ cultivation, are highlighted as promising directions to enhance preservation efficiency. By exploring current advancements and future trends, this review underscores the importance of technological innovation in addressing the global organ shortage crisis and improving transplantation outcomes. STATEMENT OF SIGNIFICANCE: This review offers a comprehensive analysis of the advancements in organ preservation technologies, a critical area in addressing the global organ shortage crisis. By detailing the evolution from early perfusion techniques to cutting-edge innovations like supercooling, vitrification, and nanotechnology, the work underscores the importance of extending organ viability and improving transplant outcomes. Importantly, it bridges historical milestones with emerging trends, showcasing how integration of novel materials and methodologies can revolutionize organ transplantation. This work not only enriches the scientific understanding of organ preservation but also opens pathways for interdisciplinary innovations, setting the stage for the development of sustainable and efficient organ banks. By aligning technological advancements with clinical challenges, it provides actionable insights that could reshape transplantation medicine.

Impact of Resuscitated Cardiac Arrest in the Brain-dead Donors on the Outcome of Liver Transplantation: A Retrospective and Propensity Score Matching Analysis

Objective

To evaluate the impact of cardiac arrest time (CAT) in brain-dead donors on graft and recipient outcomes following liver transplantation.

Background

The outcome of livers from brain-dead donors with a history of cardiac arrest (CA) remains controversial, and the duration of the CAT has never been evaluated.

Methods

A retrospective review of data from the Scientific Registry of Transplant Recipients between 2003 and 2022 was conducted. Propensity score matching was performed to minimize confounding effects.

Results

A total of 115,202 recipients were included, 7364 (6.4%) and 107,838 (93.6%) of whom were of the CA and non-CA group, respectively. After 1:1 propensity score matching, each group consisted of 7157 cases. The CA group demonstrated shorter hospital stay (15.5 ± 20.0 days vs. 16.2 ± 21.3 days, P = 0.041), with comparable incidence of early graft failure (EGF, 5.8% vs. 6.2%, P = 0.161). The CA group demonstrated slightly higher graft survival rates (1 year, 90% vs. 88%; 5 years, 76% vs. 74%; and 10 years, 61% vs. 58%, P < 0.001). CAT positively correlated with EGF [odds ratio (OR) = 1.03, 95% confidence interval (CI) = 1.02-1.04, P < 0.001], with a sensitivity and specificity of 73% and 86% at a cutoff of 30 minutes. The CAT <30 minutes group demonstrated significantly lower incidence of EGF (5.0%), compared with 7.8% of the CAT >30 minutes group and 6.2% of the non-CA group (P < 0.001).

Conclusions

The use of brain-dead donors with a history of CA did not increase the risk of liver graft failure in our study. A downtime of <30 minutes may confer protective effects on transplanted grafts.

Ex Vivo Liver Machine Perfusion: Comprehensive Review of Common Animal Models

The most common preservation technique for liver grafts is static cold storage. Due to the organ shortage for liver transplantation (LT), extended criteria donor (ECD) allografts are increasingly used-despite the higher risk of inferior outcome after transplantation. Ex vivo liver machine perfusion (MP) has been developed to improve the outcome of transplantation, especially with ECD grafts, and is currently under evaluation in clinical trials. We performed a literature search on PubMed and ISI Web of Science to assemble an overview of rodent and porcine animal models of ex vivo liver MP for transplantation, which is essential for the present and future development of clinical liver MP. Hypothermic, subnormothermic, and normothermic MP systems have been successfully used for rat and pig LT. In comparison with hypothermic systems, normothermic perfusion often incorporates a dialysis unit. Moreover, it enables metabolic assessment of liver grafts. Allografts experiencing warm ischemic time have a superior survival rate after MP compared with cold storage alone, irrespective of the temperature used for perfusion. Furthermore, ex vivo MP improves the outcome of regular and ECD liver grafts in animal models. Small and large animal models of ex vivo liver MP are available to foster the further development of this new technology. Impact Statement Ex vivo machine perfusion is an important part of current research in the field of liver transplantation. While evidence for improve storage is constantly rising, the development of future applications such as quality assessment and therapeutic interventions necessitates robust animal models. This review is intended to provide an overview of this technology in common large and small animal models and to give an outlook on future applications. Moreover, we describe developmental steps that can be followed by others, and which can help to decrease the number of animals used for experiments based on the replace, reduce, refine concept.