Associations of Oxidative Stress and Postoperative Outcome in Liver Surgery with an Outlook to Future Potential Therapeutic Options

Table 1

Findings on the role of oxidative stress/ROS during liver transplantation (animal studies).

Reference	Year	Biomarkers	Study subjects	Results
Fernandez et al. [31]	2004	SOD, GSH, , MDA	Group 1 (sham group): ; 6 lean and 6 obese Zucker rats; Group 2 (transplantation group): ; , 6 transplantations with steatotic livers being flushed with cold solution for 6 h prior to transplantation; , 6 transplantations with rats as donors and recipients; Group 3 (transplantation and preconditioning group): the same procedure as group 2 with 5 min of ischemia followed by 10 min of reperfusion prior to transplantation	SOD: an equal decrease in groups 2 and 3 was observed compared to that in the sham group; preconditioning had no effect on the decrease of SOD; GSH: decreased in group 2 but were comparable to that of the sham group in group 3; : no significant change of activity was witnessed, but in group 2, there was a conversion from XDH to XOD, which was stronger in obese rats; preconditioning attenuated this conversion; MDA: increased in group 2 compared to that in the sham group; obese rats showed a stronger increase than lean rats; preconditioning attenuated this effect
He et al. [32]	2017	ROS, H2O2	35 Sprague-Dawley rats; Group 1 (sham group): Group 2 (OLT group): Group 3 (IPostC group): , OLT with portal vein reperfusion and reocclusion for six 10-sec cycles after onset of reperfusion; Group 4 (RIPerC group): , OLT with hindlimb ischemia and reperfusion for three 5 min cycles at the beginning of the anhepatic phase; 15 donor rats	ROS: levels of ROS were significantly elevated in the OLT group compared to sham group, IPostC and RIPerC attenuated production of ROS; H2O2: levels were elevated in all groups, but lower in the sham, IPostC, and RIPerC groups compared to the OLT group
Hori et al. [33]	2014	MDA, SOD, CAT	40 Lewis rats ( each); Group 1 (control); Group 2 (60% hepatectomy); Group 3 (OLT); Group 4 (40% split OLT)	MDA: group 2, 3, and 4; group 4; SOD: group 2, 3, and 4; group 4; CAT: group 2, 3, and 4; group 4
Ngo et al. [34]	2013	MDA, tGSH	45 Sprague-Dawley rats ( each); Group 1 (isogenic control group): liver perfused with Sprague-Dawley rat whole blood; Group 2 (erythrocyte group): liver perfused with human erythrocytes and serum; Group 3 (thrombocyte group): liver perfused with human thrombocytes, erythrocytes, and serum; Group 4 (KC-group): liver perfused with human whole blood; KC depleted before reperfusion with GdCl3; Group 5 (xenogeneic whole-blood group): liver perfused with human whole blood	MDA: plasma levels significantly elevated in the xenogeneic whole blood group and in the KC group, but to a lower extent; plasma levels in all other groups are not significantly elevated; tGSH: tGSH levels fell in groups 1, 2, 3, and 5 and slowly recovered after reperfusion, although not to basal values; between groups 1, 2, and 3, there were no significant differences in tGSH levels; levels in group 5 showed the strongest decline in tGSH levels; levels in the KC group remained at basal levels
Schauer et al. [35]	2001	GSH, GSSG	22 Lewis rats; Group 1 (treatment group; ): administration of GdCl3 48 hours and 24 hours prior to harvesting; Group 2 (untreated group; ): injection of identical volumes of saline at the same timepoints as group 1; Group 3 (sham group; )	GSH: plasma levels elevated in groups 1 and 2 until the end of reperfusion but remained unchanged in the sham group; GSSG: plasma levels strongly elevated in group 2; GdCl3 pretreatment attenuated this elevation in group 1; no changes in the sham group

CAT: catalase; GdCl_3: gadolinium chloride; GSH: glutathione; GSSG: oxidized glutathione disulfide; IPostC: ischemic postconditioning; KC: Kupffer cell; MDA: malondialdehyde; OLT: orthotopic liver transplantation; RIPerC: remote ischemic preconditioning; ROS: reactive oxygen species; tGSH: total glutathione; SOD: superoxide dismutase; XDH: xanthine dehydrogenase; XOD: xanthine oxidase.