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Abstract Normothermic machine perfusion (NMP) after static cold storage is increasingly used for preservation and assessment of human donor livers prior to transplantation. Biliary viability assessment during NMP reduces the risk of post-transplant biliary complications. However, understanding of molecular changes in the biliary system during NMP remains incomplete. We performed an in-depth, unbiased proteomics analysis of bile collected during sequential hypothermic machine perfusion, rewarming and NMP of 55 human donor livers. Longitudinal analysis during NMP reveals proteins reflective of cellular damage at early stages, followed by upregulation of secretory and immune response processes. Livers with bile chemistry acceptable for transplantation reveal protein patterns implicated in regenerative processes, including cellular proliferation, compared to livers with inadequate bile chemistry. These findings are reinforced by detection of regenerative gene transcripts in liver tissue before machine perfusion. Our comprehensive bile proteomics and liver transcriptomics data sets provide the potential to further evaluate molecular mechanisms during NMP and refine viability assessment criteria.

Summary: Background: Liver transplantation is traditionally performed around the clock to minimize organ ischemic time. However, the prospect of prolonging preservation times holds the potential to streamline logistics and transform liver transplantation into a semi-elective procedure, reducing the need for nighttime surgeries. Dual hypothermic oxygenated machine perfusion (DHOPE) of donor livers for 1–2 h mitigates ischemia-reperfusion injury and improves transplant outcomes. Preclinical studies have shown that DHOPE can safely extend the preservation of donor livers for up to 24 h. Methods: We conducted an IDEAL stage 2 prospective clinical trial comparing prolonged (≥4 h) DHOPE to conventional (1–2 h) DHOPE for brain-dead donor livers, enabling transplantation the following morning. Liver allocation to each group was based on donor hepatectomy end times. The primary safety endpoint was a composite of all serious adverse events (SAE) within 30 days after transplantation. The primary feasibility endpoint was defined as the number of patients assigned and successfully receiving a prolonged DHOPE-perfused liver graft. Trial registration at: WHO International Clinical Trial Registry Platform, number NL8740. Findings: Between November 1, 2020 and July 16, 2022, 24 patients were enrolled. The median preservation time was 14.5 h (interquartile range [IQR], 13.9–15.5) for the prolonged group (n = 12) and 7.9 h (IQR, 7.6–8.6) for the control group (n = 12; p = 0.01). In each group, three patients (25%; 95% CI 3.9–46%, p = 1) experienced a SAE. Markers of ischemia-reperfusion injury and oxidative stress in both perfusate and recipients were consistently low and showed no notable discrepancies between the two groups. All patients assigned to either the prolonged group or control group successfully received a liver graft perfused with either prolonged DHOPE or control DHOPE, respectively. Interpretation: This first-in-human clinical trial demonstrates the safety and feasibility of DHOPE in prolonging the preservation time of donor livers to enable daytime transplantation. The ability to extend the preservation window to up to 20 h using hypothermic oxygenated machine preservation at a 10 °C temperature has the potential to reshape the landscape of liver transplantation. Funding: University Medical Center Groningen, the Netherlands.

Abstract Understanding habitat-level variation in community structure provides an informed basis for natural resources’ management. Reef fishes are a major component of tropical marine biodiversity, but their abundance and distribution are poorly assessed beyond conventional SCUBA diving depths. Based on a baited-video survey of fish assemblages in Southwestern Atlantic’s most biodiverse region we show that species composition responded mainly to the two major hard-bottom megahabitats (reefs and rhodolith beds) and to the amount of light reaching the bottom. Both megahabitats encompassed typical reef fish assemblages but, unexpectedly, richness in rhodolith beds and reefs was equivalent. The dissimilar fish biomass and trophic structure in reefs and rhodolith beds indicates that these systems function based on contrasting energy pathways, such as the much lower herbivory recorded in the latter. Rhodolith beds, the dominant benthic megahabitat in the tropical Southwestern Atlantic shelf, play an underrated role as fish habitats, and it is critical that they are considered in conservation planning.

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.

Shortage of deceased donor organs for transplantation has led to the increased use of organs from donation after circulatory death (DCD) donors. There are currently no reports describing outcomes after multiorgan transplantation with DCD livers. The use of DCD organs for multiorgan transplantation can be enhanced if the detrimental effects of prolonged cold ischemia and subsequent ischemia-reperfusion injury are overcome. We present a case in which the liver and lungs of a DCD donor were preserved using ex situ machine perfusion for combined liver-lung transplantation. The recipient was a 19-year-old male patient requiring bilateral lung transplantation for severe progressive pleural parenchymal fibroelastosis and portal hypertension with portal vein thrombosis. The donor liver was preserved with dual hypothermic oxygenated machine perfusion, whereas the lungs were perfused using ex vivo lung perfusion. With ex vivo lung perfusion, total preservation time of right and left lung reached 17 and 21 h, respectively. Now, 2 y after transplantation, liver function is normal and lung function is improving. To conclude, we suggest that combined transplantation of DCD liver and lungs is feasible when cold ischemia is reduced with ex situ machine perfusion preservation.

Background & Aims: End-ischemic hypothermic oxygenated machine perfusion (HOPE) of the donor liver for 1–2 h mitigates ischemia-reperfusion injury during subsequent liver transplantation. Extended preservation time may be preferred to facilitate difficult recipient hepatectomy or to optimize logistics. We therefore investigated whether end-ischemic dual HOPE (DHOPE) could extend preservation time for up to 24 h using a porcine liver reperfusion model. Methods: Following 30 min warm ischemia, porcine livers were subjected to 2 h static cold storage (SCS), followed by 2 h, 6 h, or 24 h DHOPE (n = 6 per group). Subsequent normothermic reperfusion was performed for 4 h using autologous blood. Two livers preserved by 24 h SCS served as additional controls. A proof of principle confirmation was carried out in 2 discarded human livers subjected to extended DHOPE. Hepatocellular and cholangiocyte injury and function were assessed. Oxidative stress levels and histology were compared between groups. Results: Perfusion flows remained stable during DHOPE, regardless of duration. After normothermic reperfusion, livers perfused for 24 h by DHOPE had similar lactate clearance, blood pH, glucose, and alanine aminotransferase levels, and biliary pH, bicarbonate, and LDH levels, as livers perfused for 2 h and 6 h. Levels of malondialdehyde and high-mobility group box 1 in serum and liver parenchyma were similar for all groups. Histological analysis of bile ducts and liver parenchyma revealed no differences between the groups. Extended DHOPE in discarded human livers preserved hepatocellular and cholangiocyte function and histology after reperfusion. In contrast, livers preserved by 24 h SCS were non-functioning. Conclusion: Extended end-ischemic DHOPE enabled successful preservation of porcine and discarded human donor livers for up to 24 h. Extended DHOPE enables safe extension of preservation time, which may facilitate allocation and transplantation from a logistical perspective, and further expand the donor pool. Lay summary: It has been suggested that preserving liver grafts with a technique called (dual) hypothermic oxygenated machine perfusion ([D]HOPE) leads to better outcomes after transplantation than if livers are stored on ice, especially if an organ is of lesser quality. In this study, we showed that DHOPE could be used to preserve liver grafts for up to 24 h. This extended procedure could be used globally to facilitate transplantation and expand the donor pool. Keywords: hypothermic machine perfusion, liver preservation, extended preservation, donation after circulatory death

Background: Ischemia-reperfusion injury (IRI) has been considered an inevitable event in organ transplantation since the first successful kidney transplant was performed in 1954. To avoid IRI, we have established a novel procedure called ischemia-free organ transplantation. Here, we describe the first case of ischemia-free kidney transplantation (IFKT).Materials and Methods: The kidney graft was donated by a 19-year-old brain-dead donor. The recipient was a 47-year-old man with end-stage diabetic nephropathy. The graft was procured, preserved, and implanted without cessation of blood supply using normothermic machine perfusion.Results: The graft appearance, perfusion flow, and urine production suggested that the kidney was functioning well-during the whole procedure. The creatinine dropped rapidly to normal range within 3 days post-transplantation. The levels of serum renal injury markers were low post-transplantation. No rejection or vascular or infectious complications occurred. The patient had an uneventful recovery.Conclusion: This paper marks the first case of IFKT in humans. This innovation may offer a unique solution to optimizing transplant outcomes in kidney transplantation.