Mechanisms of liver injury: an overview

Liver cirrhosis, an end-result of a wide variety of the liver diseases, is a world wide health problem. Because of its unique organ system, i.e., portal blood supply, bile formation and enterohepatic circulation, drug metabolism system, and sinusoidal lining cells such as Kupffer, endothelial and stellate cells, the liver is a target of a variety of hepatotoxic insults. Current data suggest that hepatocyte apoptosis is an essential feature contributing to liver injury in a wide range of acute and chronic liver diseases. With an improved understanding of the pathophysiological role of apoptosis in liver diseases, we are now entering an era where regulation of liver cell apoptosis is becoming a therapeutic possibility. Inhibition of hepatocyte apoptosis using a variety of different strategies may be therapeutically beneficial in liver injuries, such as alcoholic hepatitis, non-alcoholic steatohepatitis (NASH), viral hepatitis, and cholestatic liver diseases. Considering the link between hepatocyte apoptosis and liver fibrosis, inhibition of hepatocyte apoptosis may also be an anti-fibrotic therapeutic strategy. Moreover, selective induction of apoptosis of activated stellate cells would be a unique approach to induce the resolution the phase of liver fibrosis. These concepts merit further clinical and basic investigation.