Polyethylene glycols: An effective strategy for limiting liver ischemia reperfusion injury

Figure 1 Schematic composition of linear, branched and star polyethylene glycols. Polyethylene glycols (PEGs) are synthesized by a process of linking repeating units of ethylene glycol. The reaction gives products with one or two end chain hydroxyl groups termed methoxy-PEG or diol-PEG, respectively. Then, the linear PEG with branches at irregular intervals along the polymer chain forms branched PEGs. Star-shaped PEGs are the simplest class of branched PEGs with a general structure consisting of several (more than three) linear chains connected to a central core.

Figure 2 PEG35 preserves liver graft function. Confocal microscopy images showing green fluorescence of rhodamine 123 cell viability marker. Liver grafts were better preserved when they were rinsed with a solution containing PEG35 (A) rather than Ringer lactate solution (B).

Figure 3 State of the art and future perspectives of polyethylene glycols as effective tool for limiting hepatic ischemia-reperfusion injury. Currently, the clinical applications of polyethylene glycols (PEGs) focus on their use as oncotic agents in IGL-1 solution for liver transplantation (in blue). Recent experimental investigations confirm the value of PEG35 for “supercooling” strategies combined with machine perfusion, as well as its use as a component in rinse solution for liver graft washout. Intravenous PEG35 treatment has also been shown to induce liver protection against cold and warm ischemia-reperfusion injury (IRI) (in green). Future clinical applications should be investigated (in violet). PEG protection mechanisms are characterized by a prevention of mitochondrial damage and by the promotion of several cyto-protective factors during IRI (in violet).