Redox homeostasis and epigenetics in non-alcoholic fatty liver disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD), an accumulation of intra-hepatic triglycerides that is often considered the hepatic manifestation of insulin resistance, is the most common cause of chronic liver disease in the Western countries with up to one third of the population affected. NAFLD is a spectrum of disturbances that encompasses various degrees of liver damage ranging from simple steatosis to non-alcoholic steatohepatitis (NASH). NASH is characterized by hepatocellular injury/inflammation with or without fibrosis. The individuals with NAFLD develop NASH in 10% of the cases, and are also at risk of developing hepatocellular carcinoma (HCC). Epigenetic mechanisms of nuclear chromatin remodeling, such as DNA methylation, post-translational modifications of histones, and incorporation of histone variants into the chromatin are increasingly recognized as crucial factors in the pathophysiology of NAFLD. NAFLD is often accompanied by oxidative stress: reactive oxygen species (ROS) are implicated in altered reduction/oxidation (redox) reactions that attack cellular macromolecules and are detected in the liver of patients and animal models of NAFLD. In this review, we summarize recent knowledge advancements in the hepatic epigenetic and redox mechanisms, and their possible links, involved in the pathogenesis and treatment of NAFLD.