Role of immune response in nonalcoholic fatty liver disease: Evidence in human and animal studies
Nonalcoholic fatty liver disease (NAFLD) is a spectrum of hepatic pathology ranging from nonalcoholic fatty liver (NAFL; steatosis) at the most clinically benign end of the spectrum to cirrhosis at the opposite extreme, where most liver-related morbidity and mortality occur. Nonalcoholic steatohepatitis (NASH) is a lesion of intermediate severity. NASH is characterized by overt hepatocyte injury and death. It is often accompanied by hepatic infiltration with inflammatory cells (1). Some individuals with NASH gradually accumulate hepatic fibrosis, and eventually develop cirrhosis (2). Over time, hepatocellular carcinomas emerge in a small proportion of individuals with NAFLD-related cirrhosis (3). The pathogenesis of NAFLD is the subject of much research because NAFLD is one of the most common causes of chronic liver disease, particularly in countries such as the United States that are in the midst of an obesity epidemic (4,(5)). © 2007 Humana Press Inc.