Quantitative Metabolomics of Tissue, Perfusate, and Bile from Rat Livers Subjected to Normothermic Machine Perfusion.

Daniele Dondossola,Christoph Trautwein,Laimdota Zizmare,Margherita Carbonaro,Andrea Schlegel,Caterina Lonati,Michele Battistin,Stefano Gatti,Alberto Zanella,Leonie Wüst,Luigi Vivona

doi:10.3390/biomedicines10030538

Abstract

Machine perfusion (MP) allows the maintenance of liver cells in a metabolically active state ex vivo and can potentially revert metabolic perturbations caused by donor warm ischemia, procurement, and static cold storage (SCS). The present preclinical research investigated the metabolic outcome of the MP procedure by analyzing rat liver tissue, bile, and perfusate samples by means of high-field (600 MHz) nuclear magnetic resonance (NMR) spectroscopy. An established rat model of normothermic MP (NMP) was used. Experiments were carried out with the addition of an oxygen carrier (OxC) to the perfusion fluid (OxC-NMP, n = 5) or without (h-NMP, n = 5). Bile and perfusate samples were collected throughout the procedure, while biopsies were only taken at the end of NMP. Two additional groups were: (1) Native, in which tissue or bile specimens were collected from rats in resting conditions; and (2) SCS, in which biopsies were taken from cold-stored livers. Generally, NMP groups showed a distinctive metabolomic signature in all the analyzed biological matrices. In particular, many of the differentially expressed metabolites were involved in mitochondrial biochemical pathways. Succinate, acetate, 3-hydroxybutyrate, creatine, and O-phosphocholine were deeply modulated in ex vivo perfused livers compared to both the Native and SCS groups. These novel results demonstrate a broad modulation of mitochondrial metabolism during NMP that exceeds energy production and redox balance maintenance.

Highlights

The introduction of machine perfusion (MP) significantly changed the clinical scenario of liver transplantation by enabling prolonged ex situ preservation, evaluation, and reconditioning of grafts previously deemed unsuitable [1,2]
Baseline perfusate composition was different in the two normothermic MP (NMP) groups due to the presence of different compounds necessary to preserve oxyglobin (Supplementary Table S2)
DO2 was lower in the NMP group compared to the oxygen carrier (OxC)-NMP group (p < 0.001)

Summary

Introduction

The introduction of machine perfusion (MP) significantly changed the clinical scenario of liver transplantation by enabling prolonged ex situ preservation, evaluation, and reconditioning of grafts previously deemed unsuitable [1,2]. Biomedicines 2022, 10, 538 metabolic activation [3,4] This condition could promote the induction of beneficial endogenous pathways to cope with the detrimental consequences of ischemia/reperfusion (IR) [5]. Activation of specific metabolic events within cells and mitochondria can contribute to a poor transplant outcome [8,10]. Metabolomic profiling of liver biopsies collected at different stages of liver transplantation provided useful information to determine the extent of organ injury related to cold ischemia [14], to assess the recovery rate post transplantation [14,15], and to identify prognostic markers of graft and dysfunction and acute rejection [16,17,18]

Methods

Discussion

Conclusion