Single-cell transcriptomic profiling reveals cellular stress responses to hypothermic preservation in liver-on-chip...

Cold preservation is a critical logistical step in liver transplantation but induces ischemia-reperfusion injury (IRI), a key driver of early graft dysfunction. While bulk tissue assays capture global damage, they obscure the cell-type-specific transcriptional programs engaged during hypothermic storage. We utilized a multicellular human liver-on-chip model comprising Patient-Derived Organoids (PDOs), hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs), and macrophages. Chips were exposed to 24-h static cold storage using either the clinical standard University of Wisconsin (UW) solution or a hyperbranched polyglycerol (HPG)-based formulation, followed by normothermic reperfusion. Single-cell RNA sequencing (scRNA-seq) was performed to map transcriptional trajectories across the preservation-reperfusion axis. We identified candidate solution-dependent transcriptional differences across cell types. PDOs from UW-preserved chips showed comparatively higher mean expression of inflammatory and oxidative stress-associated transcripts (IFI27, SAA1, HMOX1) and mitochondrially-encoded genes (MT-ND5) relative to HPG-preserved samples, which retained comparatively higher expression of homeostatic epithelial markers (EPCAM, KRT18). HSCs and LSECs in the UW group showed comparatively elevated expression of fibrosis-associated (COL1A1, TAGLN) and endothelial adhesion (ICAM1) transcripts. Ligand-receptor interaction modelling identified candidate inflammatory communication axes, including chemokine signaling interactions (CXCL1, CCL20) between macrophages and epithelial compartments, with higher predicted activity under UW preservation. This study provides an exploratory, high-resolution map of cell-type-specific transcriptional patterns associated with hypothermic preservation in a liver-on-chip model. Our findings suggest that preservation solution chemistry is associated with distinct transcriptional signatures spanning stress response, mitochondrial, and intercellular signaling pathways. Transcriptional patterns in HPG-preserved cells were consistent with comparatively attenuated injury responses; however, these observations are hypothesis-generating and require independent biological replication and functional validation, including metabolic flux assays and ROS production measurements before conclusions regarding mitochondrial protection or clinical preservation efficacy can be drawn.