Visualizing and targeting oxidative stress in hepatic ischemia-reperfusion injury

Ischemia-reperfusion (IR) injury is the inevitable result of liver resection performed using vascular inflow occlusion (VIO), which entails clamping of the afferent hepatic blood supply. Hepatocellular oxidative stress forms a pivotal aspect of IR injury, predominantly during the early (0–30 min) phase of reperfusion. Although the development of methods to analyze oxidative stress in vitro and in vivo is challenging, redox-active fluorogenic probes such as 2’,7’-dichlorodihydrofluorescein diacetate (DCFH2-DA) are commonly used for this purpose. The expression of membrane transporter proteins on hepatocytes and hepatocyte-derived cell lines however imposes limitations on the use of such probes on hepatocyte(-derived) cells. The use of DCFH2-DA was therefore optimized for hepatocyted-derived HepG2 and HepaRG cells. A method was furthermore developed to prepare DCFH2 from DCFH2-DA, the utility of which was demonstrated through a variety of in vitro experiments. A hepatocyte-targeted liposomal drug delivery system was moreover developed to target 5(6)-carboxy-DCFH2 to hepatocytes in vivo for the selective quantification of hepatocellular oxidative stress using a mouse model for IR. In addition, the protective effect of hypothermia on IR injury was investigated using a new method for in situ hypothermic perfusion (IHP). The utility of this new technique, which encompasses retrograde outflow (IHP-R), was investigated in patients undergoing a right hemihepatectomy together with VIO. IHP-R was compared to intermittent VIO, the gold standard method, in which it was shown that IHP-R could possible improve early functional liver regeneration following VIO. However, more research needs to be performed to ascertain this presumed beneficial effect of IHP-R.