Molecular and proteomic signatures associated with preservation related graft injury: insight from human liver normothermic achine perfusion (NMP)

Abstract

Fungai Dengu¹; Sadr Shaheed¹; Letizia Lo Faro¹; Adam Thorne¹; Honglei Huang¹; Peter Friend¹,
Rutger Ploeg¹.

1. Oxford Organ Perfusion Lab, Nuffield Department of Surgical Sciences and Oxford Biomedical
Research Centre, University of Oxford, Oxford, UK

Background
Continuous liver NMP is a novel technology associated with safe extension of organ
preservation time, increased organ utilisation and reduced early graft injury1. Increasingly, it is
utilised as a ‘back to base’ application with cold storage for organ transport and NMP initiated
at the implanting centre prior to transplantation2. We aimed to evaluate the impact of
additional cold ischaemia time (CIT) on the proteomic and molecular signature of NMP livers.

Methods
Liver tissue samples (N= 57) from a prospective clinical trial of ‘back to base’ NMP were
analysed. Collection occurred at the end of cold storage (LT1), end of NMP/total preservation
(LT2) and after organ reperfusion (LT3). Unbiased, label-free-quantitative (LFQ) proteomic
analysis was conducted using liquid chromatography with tandem mass spectrometry and
trapped ion mobility spectrometry (TIMS) to time-of-flight (TOF) mass analysis (LC-MS/MS TIMSTOF).
Differential expression and Gene Ontology/Pathway analysis were performed.

Results
LT2 samples with prolonged CIT (>6hr) prior to NMP had significant differential expression of
proteins associated with liver-specific oxidative stress, cellular haemostasis and removal of
damaged or misfolded proteins (e.g. CYP3A5, PSMB1). LT3 samples, similarly, had reduced
proteins involved in autophagy and cell-cycle regulation (e.g. STBD1, CD2AP, GADD45GIP1,) and
increased expression of proteins involved in neutrophil chemotaxis, adhesion and aggregation
(e.g. S100A9).

Discussion
The molecular signature of grafts at LT2 and LT3 varies depending on the length of CIT prior to
NMP. Further exploration of the molecular signatures associated with preservation related graft
injury is required to determine how best to apply this novel technology clinically.

References:
1. Nasralla, D. et al. A randomized trial of normothermic preservation in liver
transplantation. Nature 557, 50–56 (2018).
2. Ceresa, C. D. L. et al. Transient Cold Storage Prior to Normothermic Liver Perfusion May
Facilitate Adoption of a Novel Technology. Liver Transplant. lt.25584 (2019).
doi:10.1002/lt.25584