Carbonic Anhydrase Protects Fatty Liver Grafts against Ischemic Reperfusion Damage.

Mohamed Bejaoui,Georgina Hotter,Emma Folch-Puy,Joan Rosselló-Catafau,Viviana De Luca,Clemente Capasso,Arnau Panisello,Claudiu T Supuran,Eirini Pantazi,Jordi Gracia-Sancho

doi:10.1371/journal.pone.0134499

Abstract

Carbonic anhydrases (CAs) are ubiquitous metalloenzymes that catalyze the reversible hydration of carbon dioxide to bicarbonate and a proton. CAs are involved in numerous physiological and pathological processes, including acid-base homeostasis, electrolyte balance, oxygen delivery to tissues and nitric oxide generation. Given that these processes are found to be dysregulated during ischemia reperfusion injury (IRI), and taking into account the high vulnerability of steatotic livers to preservation injury, we hypothesized a new role for CA as a pharmacological agent able to protect against ischemic damage. Two different aspects of the role of CA II in fatty liver grafts preservation were evaluated: 1) the effect of its addition to Institut Georges Lopez (IGL-1) storage solution after cold ischemia; 2) and after 24h of cold storage followed by two hours of normothermic ex-vivo perfusion. In all cases, liver injury, CA II protein concentration, CA II mRNA levels and CA II activity were determined. In case of the ex-vivo perfusion, we further assessed liver function (bile production, bromosulfophthalein clearance) and Western blot analysis of phosphorylated adenosine monophosphate activated protein kinase (AMPK), mitogen activated protein kinases family (MAPKs) and endoplasmic reticulum stress (ERS) parameters (GRP78, PERK, IRE, eIF2α and ATF6). We found that CA II was downregulated after cold ischemia. The addition of bovine CA II to IGL-1 preservation solution efficiently protected steatotic liver against cold IRI. In the case of reperfusion, CA II protection was associated with better function, AMPK activation and the prevention of ERS and MAPKs activation. Interestingly, CA II supplementation was not associated with enhanced CO2 hydration. The results suggest that CA II modulation may be a promising target for fatty liver graft preservation.

Highlights

Ischemia reperfusion injury (IRI) is the main cause of early allograft dysfunction after organ transplantation [1]
This situation was reversed by Carbonic anhydrases (CAs) II addition to IGL-1 solution, as revealed by the increased CA II staining in the IGL+CAII group
We found that CA II mRNA expression decreased after cold storage and the addition of CA II did not affect mRNA expression

Summary

Introduction

Ischemia reperfusion injury (IRI) is the main cause of early allograft dysfunction after organ transplantation [1]. During liver graft storage in preservation solutions (cold ischemia), several. The worldwide shortage of donor organs has led to the expansion of donor criteria to include suboptimal grafts such as steatotic livers, which in the past were excluded from transplantation [3] due to their association with primary non-function and delayed graft function [4]. It is well known that fatty livers are more vulnerable to IRI than non-fatty ones. This situation required the development of new alternatives to the University of Wisconsin preservation solution (UW), mainly used for abdominal organs, to improve both the conservation of these suboptimal liver grafts and the outcomes of transplantation [5, 6]. IGL-1 solution has been found to decrease endoplasmic reticulum stress (ERS) which leads to the inhibition of liver apoptosis [9]

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