Portosystemic collaterals are not prerequisites for the development of hepatic encephalopathy in cirrhotic rats.

BACKGROUND Liver functions and portosystemic collaterals influence the development and severity of hepatic encephalopathy (HE) in cirrhosis. However, it has not been examined which factor has a greater influence or if shunts can be used to determine the presence and severity of HE. The expression of tumor necrosis factor-α (TNF-α) is increased in cirrhosis, and its role in HE deserves further evaluation. METHODS Portal hypertension was induced by portal vein ligation (PVL; a model of high-degree portosystemic shunting without significant liver damage) and liver cirrhosis was induced by bile duct ligation (BDL; a model of low-degree shunting with liver cirrhosis) in male Spraque-Dawley rats. Sham-operated rats were used as controls. Motor activity counts, hemodynamic parameters, plasma levels, liver biochemistry parameters, TNF-α, and a flow-pressure curve study of portosystemic collaterals (where a higher slope indicates fewer portosystemic collaterals) were performed on Day 7 after PVL and Week 5 after BDL. RESULTS Portal pressure was significantly higher in the PVL and BDL groups than in controls. The liver biochemistry parameters, TNF-α, and motor activities were not significantly different between the PVL and PVL-control groups. In the BDL group, TNF-α, AST, and total bilirubin levels were significantly higher and the motor activity counts were lower than in the BDL-control group. Moreover, in the BDL rats, TNF-α (p=0.037, R=-0.490), AST (p=0.007, R=-0.595) and total bilirubin (P=0.001, R=-0.692) levels, but not the slopes of the flow-pressure curves, were significantly and negatively correlated with the motor activity counts. CONCLUSION The presence of a high degree of portosystemic shunting without significant liver damage may not be adequate for the development of HE.