How much oxidative stress exists without the liver?

Oxidative stress (OS) represents an important pathogenetic factor of acute liver failure and chronic liver diseases. To elucidate whether the liver itself is a major source of OS, the present study was performed to assess OS and antioxidant status in an anhepatic porcine model.

Six pigs underwent a total hepatectomy, five pigs were sham operated. OS and antioxidant status were evaluated by measuring plasma concentrations of malondialdehyde (MDA), xanthine oxidase (XO), superoxide dismutase (SOD) and the ferric reducing ability of plasma (FRAP). They were sampled at the start of the experiment, immediately after surgery, and then at 8 and 16 hours post hepatectomy.

Increased concentrations of MDA were observed in anhepatic pigs postoperatively (p < 0.02) and 8 hours after hepatectomy (p < 0.003) compared to controls. XO activity increased soon after hepatectomy (22.6 ± 5.4 mU/L versus 3.3 ± 2.1 mU/L in sham animals, p < 0.03) but returned to normal values in the further course. SOD levels did not change during the observational period in both groups. FRAP values rose significantly in the anhepatic animals compared to control (p < 0.015). A significant positive correlation was observed between MDA levels and FRAP levels (Spearman's ρ = 0.62; p < 0.0001).

These findings show that hepatectomy does not completely prevent the occurrence of OS because the production and regulation of OS are also located outside the liver.