Non-alcoholic fatty liver disease: Epidemiology, pathophysiology and an update on the therapeutic approaches

Non-alcoholic fatty liver disease (NAFLD) denotes a spectrum of fatty liver disease in individuals without significant alcohol consumption. NAFLD is set to be the most common etiology of serious liver diseases in numerous nations when accompanied by obesity and type 2 diabetes. It is further histologically categorized into the non-alcoholic fatty liver (NAFL; steatosis without hepatocellular injury) and non-alcoholic steatohepatitis (NASH) which is characterized by the coexistence of hepatic steatosis and inflammation and is accompanied by hepatocyte injury (ballooning), either with or without fibrosis. NAFL is considered the benign and reversible stage arising from the excessive accumulation of triglycerides in hepatocytes. However, NASH is a more progressive stage of NAFLD, due to the increased risks of evolving more serious diseases such as cirrhosis, hepatocellular carcinoma. This concept, however, has been lately challenged by a hypothesis of multiple parallel hits of NAFLD, in which steatosis and NASH are separate entities rather than two points of the NAFLD spectrum, not only from a set of histological patterns but also from a pathophysiological perspective. The current review highlights the epidemiology and pathophysiology of NAFLD, and its progression towards steatohepatitis, with special focus on the novel imminent therapeutic approaches targeting the molecular aspects and the pathogenic pathways involved in the development, and progression of NAFLD.