Mitigating Cold Ischemic Injury: HTK, UW and IGL-2 Solution's Role in Enhancing Antioxidant Defence and Reducing Inflammation in Steatotic Livers

Abstract

Liver transplantation remains the only definitive treatment for end-stage liver diseases. However, the increasing prevalence of fatty liver disease among potential donors exacerbates the shortage of suitable organs. This study evaluates the efficacy of the preservation solution Institut Georges Lopez-2 (IGL-2) compared to Histidine-Tryptophan-Ketoglutarate (HTK) and University of Wisconsin (UW) preservation solutions in mitigating ischemia-reperfusion injury (IRI) in steatotic livers. Using Zucker Obese rat livers, we assessed the impact of 24-h static cold storage (SCS) with each solution on transaminase release, glutathione redox balance, antioxidant enzyme activity, lipoperoxidation, and inflammation markers. IGL-2 and UW solutions demonstrated reduced transaminase and lactate levels compared to HTK, indicating better preservation of liver integrity. IGL-2 maintained a higher reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, suggesting more effective management of oxidative stress. Antioxidant enzyme activities catalase, superoxide dismutase, and glutathione peroxidase (CAT, SOD, GPX) were higher in IGL-2 preserved livers, contributing to decreased oxidative damage. Lipid peroxidation markers and inflammatory markers were lower in IGL-2 than in HTK, indicating reduced oxidative stress and inflammation. Additionally, improved mitochondrial function was observed in the IGL-2 group, correlating with reduced reactive oxygen species (ROS) production and lipid peroxidation. These findings suggest that IGL-2 offers superior preservation of liver viability, reduces oxidative stress, and minimizes inflammation compared to HTK and UW solutions. By maintaining a higher ratio of reduced glutathione and antioxidant enzyme activity, IGL-2 effectively mitigates the harmful effects of ischemia-reperfusion injury. The reduced lipid peroxidation and inflammation in the IGL-2 group further underscore its potential in improving liver transplant outcomes. These results highlight the importance of optimizing preservation solutions to enhance the viability and functionality of donor organs, potentially expanding the donor pool and improving the success rates of liver transplantation. Future research should focus on refining preservation techniques and exploring additional protective agents to further improve organ preservation and transplant outcomes.

Keywords: HTK; IGL-2; UW; ischemic injury; oxidative stress; preservation solutions; static cold storage; steatotic liver; sterile inflammation.

Figure 1

Relationships among transaminase activity (GOT, GPT), pH levels, and lactate concentration. This figure shows the release of transaminases (GOT and GPT), lactate levels, and pH in perfusates from fatty livers subjected to 24-h cold storage in IGL-2, HTK, and UW solutions. Control group without ischemia (SHAM) included. Results expressed as mean ± SEM. a p < 0.5 vs. SHAM, b p < 0.5 vs. HTK.

Figure 2

Association of uric acid, HMGB1, IL-6, AIM2, and NLRP3 levels in inflammatory responses. DAMPs measured as HMGB1 and acid uric, inflammasome, measured as AIM2 and NLRP3 and inflammatory related cytokines measured as IL-6 levels were assessed. Results expressed as mean ± SEM. a p < 0.5 vs. SHAM, b p < 0.5 vs. HTK.

Figure 3

Correlation between GRP78, oxidative stress markers (TBARS, AOPP, 4HNE), and ALDH2 activity. Assessment of endoplasmic reticulum stress (GRP78), lipoperoxidation (TBARS, AOPP, 4HNE) and lipoperoxidation sub-products antagonists (ALDH2) were analysed. Results expressed as mean ± SEM. a p < 0.5 vs. SHAM, c p < 0.5 vs. UW.

Figure 4

Interaction between glutathione levels (GSH, GSSG), glutathione reductase (GR) activity, and the GSH/GSSG ratio. Reduced glutathione (GSH), oxidized glutathione (GSSH), it’s ratio and glutathione reductase (GR) levels were assessed. Results expressed as mean ± SEM. a p < 0.5 vs. SHAM, b p < 0.5 vs. HTK.

Figure 5

Comparison of enzymatic antioxidant activity: GST, GPx, CAT, and SOD levels. Evaluation of alterations in catalase (CAT), superoxide dismutase (SOD), glutathione S-transferase (GST), and glutathione peroxidase (GPX) enzyme profiles involved in other antioxidant mechanisms. Results expressed as mean ± SEM. a p < 0.5 vs. SHAM, b p < 0.5 vs. HTK.

Scheme 1

The scheme illustrates the interconnections among various biochemical pathways. Increases and decreases in compound levels are depicted at the respective points of their occurrence (beginning of grey arrows) with increment shape, while thick arrows indicate the influence (pointing upwards, increasing, pointing downwards, decreasing) on subsequent pathways at the end of the grey arrows. Negative impacts on overall cellular damage are highlighted in red, whereas beneficial cytoprotective effects are shown in green. In the scheme we observe that an increase in ROS is associated with greater damage, while an increase in ATP is associated with its reduction.