The Role of IGL-2 Preservation Solution on Rat Livers during SCS and HOPE.

The scarcity of livers for transplantation is rising, and new strategies to extend the donor pool are being explored. One solution is to use marginal grafts from extended criteria donors, presenting, for example, liver steatosis. As current preservation solutions (UW, HTK, and IGL-1) were mainly designed for static cold storage (SCS) only, IGL-2, a modified version of IGL-1, was developed to be suitable for SCS and dynamic preservation, such as hypothermic oxygenated perfusion (HOPE). In this study, we investigated the combined effect of IGL-2, SCS, and HOPE and compared it to the most used preservation solution (UW and Belzer MPS). Four experimental groups with six rats each were designed using Zucker rats. All groups underwent 24 h of SCS (in IGL-2 or UW) + 2 h of normothermic machine perfusion (NMP) at 37 °C to mimic transplantation. HOPE (IGL-2 or Belzer MPS) was performed before NMP on half of the rats. The IGL-2 group demonstrated lower transaminases and a significantly low level of glycocalyx proteins, CASP3, and HMGB1 in the perfusates. These data suggest the protective role of IGL-2 for fatty livers in preserving the endothelial glycocalyx, apoptosis, and inflammation.

Pre-Ischemic Hypothermic Oxygenated Perfusion Alleviates Protective Molecular Markers of Ischemia-Reperfusion Injury in Rat Liver.

To expand the pool of organs, hypothermic oxygenated perfusion (HOPE), one of the most promising perfusion protocols, is currently performed after cold storage (CS) at transplant centers (HOPE-END). We investigated a new timing for HOPE, hypothesizing that performing HOPE before CS (HOPE-PRE) could boost mitochondrial protection allowing the graft to better cope with the accumulation of oxidative stress during CS. We analyzed liver injuries at 3 different levels. Histologic analysis demonstrated that, compared to classical CS (CTRL), the HOPE-PRE group showed significantly less ischemic necrosis compared to CTRL vs HOPE-END. From a biochemical standpoint, transaminases were lower after 2 hours of reperfusion in the CTRL vs HOPE-PRE group, which marked decreased liver injury. qPCR analysis on 37 genes involved in ischemia-reperfusion injury revealed protection in HOPE-PRE and HOPE-END compared to CTRL mediated through similar pathways. However, the CTRL vs HOPE-PRE group demonstrated an increased transcriptional level for protective genes compared to the CTRL vs HOPE-END group. This study provides insights on novel biomarkers that could be used in the clinic to better characterize graft quality improving transplantation outcomes.

A Novel Oxygen Carrier (M101) Attenuates Ischemia-Reperfusion Injuries during Static Cold Storage in Steatotic Livers.

The combined impact of an increasing demand for liver transplantation and a growing incidence of nonalcoholic liver disease has provided the impetus for the development of innovative strategies to preserve steatotic livers. A natural oxygen carrier, HEMO2life®, which contains M101 that is extracted from a marine invertebrate, has been used for static cold storage (SCS) and has shown superior results in organ preservation. A total of 36 livers were procured from obese Zucker rats and randomly divided into three groups, i.e., control, SCS-24H and SCS-24H + M101 (M101 at 1 g/L), mimicking the gold standard of organ preservation. Ex situ machine perfusion for 2 h was used to evaluate the quality of the livers. Perfusates were sampled for functional assessment, biochemical analysis and subsequent biopsies were performed for assessment of ischemia-reperfusion markers. Transaminases, GDH and lactate levels at the end of reperfusion were significantly lower in the group preserved with M101 (p < 0.05). Protection from reactive oxygen species (low MDA and higher production of NO2-NO3) and less inflammation (HMGB1) were also observed in this group (p < 0.05). Bcl-1 and caspase-3 were higher in the SCS-24H group (p < 0.05) and presented more histological damage than those preserved with HEMO2life®. These data demonstrate, for the first time, that the addition of HEMO2life® to the preservation solution significantly protects steatotic livers during SCS by decreasing reperfusion injury and improving graft function.