Basic Study
Copyright ©The Author(s) 2017. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Oct 28, 2017; 23(40): 7221-7231
Published online Oct 28, 2017. doi: 10.3748/wjg.v23.i40.7221
Hypothermic machine perfusion with metformin-University of Wisconsin solution for ex vivo preservation of standard and marginal liver grafts in a rat model
Yi-Chao Chai, Guo-Xin Dang, Hai-Qi He, Jian-Hua Shi, Hong-Ke Zhang, Rui-Tao Zhang, Bo Wang, Liang-Shuo Hu, Yi Lv
Yi-Chao Chai, Hai-Qi He, Jian-Hua Shi, Hong-Ke Zhang, Bo Wang, Liang-Shuo Hu, Yi Lv, Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Yi-Chao Chai, Guo-Xin Dang, Hai-Qi He, Jian-Hua Shi, Hong-Ke Zhang, Liang-Shuo Hu, Yi Lv, Institute of Advanced Surgical Techniques and Engineering, Regenerative Medicine and Surgery Engineering Research Center of Shaanxi Province, Xi’an Jiaotong University, Xi’an 710061, Shaanxi Province, China
Guo-Xin Dang, Rui-Tao Zhang, Department of Hepatobiliary and Vascular Surgery, the 521 Hospital of Ordnance Industry, Xi’an 710065, Shaanxi Province, China
Author contributions: Chai YC and Dang GX contribute equally to this study; Dang GX and Hu LS conceived and designed the experimental study; Chai YC and Dang GX performed the surgical procedure; Chai YC and Zhang HK collected the data; Zhang HK provided statistical analysis; Dang GX and Zhang RT contributed to data interpretation; He HQ and Shi JH reviewed all histopathological specimens and performed morphometric measurements; Chai YC wrote the article; Hu LS, LvY and Wang B critically revised the article; all authors participated in the revision of the manuscript, read and approved the final manuscript.
Supported by the National Natural Science Foundation, No. 81470896; the Project of Development and Innovation Team of Ministry of Education, No. IRT_16R57.
Institutional review board statement: The animal experiment protocol of this paper was approved by the Laboratory Animal Administration Committee of Xi’an Jiaotong University (approval No. XJTULAC 2013001), carried out according to the Guidelines for Animal Experimentation of Xi’an Jiaotong University and Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health (NIH Publication number 85-23, revised 2011).
Conflict-of-interest statement: All the authors declare no conflict of interest related to this publication.
Data sharing statement: No additional data are available.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Liang-Shuo Hu, MD, Department of Hepatobiliary Surgery, First Affiliated Hospital of Xi’an Jiaotong University, No. 277, West Yanta Road, Xi’an 710061, Shaanxi Province, China. huliangshuo1983@hotmail.com
Telephone: +86-29-85323900 Fax: +86-29-85252580
Received: August 18, 2017
Peer-review started: August 19, 2017
First decision: August 29, 2017
Revised: September 10, 2017
Accepted: September 20, 2017
Article in press: September 19, 2017
Published online: October 28, 2017
Processing time: 71 Days and 14.7 Hours
ARTICLE HIGHLIGHTS
Background

Liver transplantation is the only effective therapy for end-stage liver disease. At present, due to the shortage of liver donation, marginal donation, which includes aged donation, adipo-hepatic donation, and donation after cardiac death, increases the risk for more severe ischemic reperfusion injury (IRI) because of suboptimal function and long-term warm and cold ischemia. Therefore, there is a current pressing need to explore and improve methods of organ preservation and minimize IRI of donor livers during transplantation.

Research frontiers

According to the latest research, machine perfusion has been meaningful for the preservation and repair of marginal liver donation. Another important direction of research on donor liver cold preservation is the auxiliary protective intervention of donor livers against IRI factors of microcirculation and hepatocyte metabolism through drugs. Activation of adenosine 5’-monophosphate-activated protein kinase (AMPK) signaling pathways increases eNOS activity to generate nitric oxide (NO), which plays an important role in the protection of liver sinusoidal endothelial cells. Metformin is an agonist of AMPK. Hence, we assumed that liver sinusoidal endothelial cells can be protected from injury by activating AMPK signaling pathways with the addition of metformin perfused in vitro, which could ultimately cause an improvement of liver donor organ preservation.

Research objectives

In this study, we added metformin to University of Wisconsin (UW) solution, to compare the effect of UW solution with or without metformin, an AMPK activator, for preserving standard and marginal criteria liver grafts of young and aged rats ex vivo by hypothermic machine perfusion (HMP).

Research methods

Eighteen young (4-mo-old) and 18 aged (17-mo-old) healthy male SD rats were selected and randomly divided into three groups: control group, UW solution perfusion group (UWP), and UW solution with metformin perfusion group (MUWP). Aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LDH), interleukin-18 (IL-18), and tumor necrosis factor-alpha (TNF-α) in the perfused liquid were tested. The expression levels of AMPK and eNOS in liver sinusoidal endothelial cells were also examined. Additionally, microscopic evaluation of the harvested perfused liver tissue samples was done.

Research results

AST, ALT, LDH, IL-18 and TNF-α levels in the young and aged liver-perfused liquid in the MUWP group were, respectively, significantly lower than those in the UWP group (P < 0.05), but no significant differences between the young and aged MUWP groups were found. Metformin increased the expression of AMPK and eNOS protein levels, and promoted the extracellular release of nitric oxide through activation of the AMPK-eNOS mediated pathway. Histological examination revealed that in the MUWP group, the extent of liver cells and tissue damage was significantly reduced compared with the UWP group.

Research conclusions

This experiment confirmed that the addition of metformin to organ preservation solution can activate AMPK/eNOS pathway, which can not only reduce injury to ex vivo rat livers during cold ischemia, but can reduce the difference between aged and young livers after HMP, with especially significant effects of protecting livers of aged rats, which should probably improve the utilization of marginal liver donor tissues. However, whether metformin can sequentially improve hepatic injury during reperfusion-ischemia requires further investigation. But at least, we provided a novel idea, which is also a simple procedure for drug auxiliary intervention with HMP in ex vivo rat donor livers and deserves further research with a promising prospect.