Method of Direct Segmental Intra-hepatic Delivery Using a Rat Liver Hilar Clamp Model

Intrahepatic Delivery of Pegylated Catalase Is Protective in a Rat Ischemia/Reperfusion Injury Model

BACKGROUND

Ischemia/reperfusion injury (IRI) can occur during liver surgery. Endogenous catalase is important to cellular antioxidant defenses and is critical to IRI prevention. Pegylation of catalase (PEG-CAT) improves its therapeutic potential by extending plasma half-life, but systemic administration of exogenous PEG-CAT has been only mildly therapeutic for hepatic IRI. Here, we investigated the protective effects of direct intrahepatic delivery of PEG-CAT during IRI using a rat hilar clamp model.

MATERIALS AND METHODS

PEG-CAT was tested in vitro and in vivo. In vitro, enriched rat liver cell populations were subjected to oxidative stress injury (H₂O₂), and measures of cell health and viability were assessed. In vivo, rats underwent segmental (70%) hepatic warm ischemia for 1 h, followed by 6 h of reperfusion, and plasma alanine aminotransferase and aspartate aminotransferase, tissue malondialdehyde, adenosine triphosphate, and GSH, and histology were assessed.

RESULTS

In vitro, PEG-CAT pretreatment of liver cells showed substantial uptake and protection against oxidative stress injury. In vivo, direct intrahepatic, but not systemic, delivery of PEG-CAT during IRI significantly reduced alanine aminotransferase and aspartate aminotransferase in a time-dependent manner (P < 0.01, P < 0.0001, respectively, for all time points) compared to control. Similarly, tissue malondialdehyde (P = 0.0048), adenosine triphosphate (P = 0.019), and GSH (P = 0.0015), and the degree of centrilobular necrosis, were improved by intrahepatic compared to systemic PEG-CAT delivery.

CONCLUSIONS

Direct intrahepatic administration of PEG-CAT achieved significant protection against IRI by reducing the volume distribution and taking advantage of the substantial hepatic first-pass uptake of this molecule. The mode of delivery was an important factor for protection against hepatic IRI by PEG-CAT.