A comprehensive multi-omics analysis published in Nature Medicine provides new mechanistic insights into extracorporeal liver cross-circulation (ELC) using gene-edited porcine liver xenografts, advancing understanding of the molecular and cellular interactions that will shape the clinical translation of xenogeneic liver support.
The study builds on a previously reported first-in-human decedent model in which blood from four brain-dead human recipients was circulated through ten-gene-edited porcine livers for up to 84 hours. While the initial work demonstrated that ELC could provide meaningful metabolic support, significant thrombocytopenia and evidence of host immune activation remained major barriers. The new study applies longitudinal, species-resolved multi-omics to dissect these biological responses at unprecedented resolution.
Researchers from NYU Langone Health, NYU Grossman School of Medicine, and the Perelman School of Medicine at the University of Pennsylvania profiled 64 serial blood samples using proteomics, metabolomics, and lipidomics alongside spatial transcriptomic analysis of 25 porcine liver biopsies and three native human liver samples. This integrated approach enabled simultaneous tracking of human and porcine molecular signatures throughout the xenoperfusion procedures.
Spatial transcriptomics revealed progressive infiltration of human innate immune cells into the porcine xenografts, dominated by inflammatory macrophages and neutrophils. These infiltrating cells expressed pro-inflammatory cytokines including IL1B, TNF, and IL6, while resident porcine Kupffer-like macrophages and T cells declined over time. Adaptive immune cell infiltration remained comparatively limited, suggesting that the extensive genetic engineering of the donor pigs may mitigate early adaptive rejection during short-term support.
One of the study’s most important findings was the distinct behavior of the human and porcine complement systems. While human complement proteins declined during ELC, the pig liver continued producing high levels of complement components C3 and C5 alongside acute-phase proteins and coagulation factors. The findings suggest that the xenograft actively drives innate immune and inflammatory responses rather than simply replacing liver function. Because currently available complement inhibitors are designed to target human proteins, they may not adequately suppress pig-derived complement activity, highlighting a potential need for species-specific therapeutics and additional genetic engineering to improve xenograft compatibility.
The investigators also identified candidate mechanisms underlying the profound thrombocytopenia consistently observed during ELC. Human platelets rapidly accumulated within the porcine liver, where they colocalized with activated sinusoidal endothelial cells expressing increasing levels of porcine von Willebrand factor (vWF), as well as infiltrating macrophages, neutrophils, and hepatocytes. Elevated expression of platelet adhesion receptors and evidence of platelet activation, aggregation, and phagocytosis point to a multifactorial process involving endothelial activation, innate immune responses, and platelet clearance pathways. These findings nominate multiple potential therapeutic targets, including porcine-specific vWF interactions and complement-mediated inflammatory signaling.
Beyond immune compatibility, the multi-omics analyses demonstrated sustained hepatic metabolic activity throughout the procedures. The xenografts supported bilirubin clearance, amino acid metabolism, detoxification, and synthesis of albumin, transferrin, apolipoproteins, and coagulation factors. In one recipient who underwent hepatectomy, the extracorporeal pig liver maintained critical metabolic functions for more than 48 hours in the absence of a native liver, although circulating lipid levels remained reduced during exclusive xenograft support.
The study also illustrates the growing value of systems biology approaches in transplantation research. By integrating longitudinal proteomic, metabolomic, lipidomic, and spatial transcriptomic datasets, investigators were able to distinguish donor- and recipient-derived biological processes while identifying dynamic molecular networks that would likely remain undetected using conventional analyses.
Although the cohort comprised only five ELC procedures in four decedents, it represents the most comprehensive molecular characterization of pig-to-human liver xenoperfusion reported to date. The findings provide a roadmap for improving xenograft biocompatibility through both genetic engineering and targeted therapeutics, while establishing species-resolved multi-omics as a powerful platform for biomarker discovery and mechanism-driven optimization of xenotransplantation strategies.
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