Treatment of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is very common in the United States, and in some patients it may lead to cirrhosis, liver failure, and liver cancer. NAFLD encompasses a spectrum of liver injury, ranging from steatosis to steatohepatitis, advanced fibrosis, and cirrhosis. Nonalcoholic steatohepatitis (NASH), an advanced form of NAFLD, histologically comprises steatosis, balloon degeneration, inflammation, and fibrosis in varying degrees. It is generally believed that simple steatosis is benign with minimal risk of progression, whereas NASH is progressive and can lead to cirrhosis. The commonly associated risk factors for NAFLD include obesity, hyperlipidemia, and diabetes mellitus. The pathogenesis of NAFLD and NASH is not fully known; however, current evidence suggests that insulin resistance and lipid peroxidation play a role in the pathogenesis of this condition. Currently, there are no proven effective therapies available for the treatment of NASH. Although there are numerous studies that have explored various treatments for NASH, these generally consist of small numbers of patients with suboptimal endpoints. Treatment strategies for NAFLD and NASH can be broadly divided into 1) treatment or control of underlying risk factors such as hyperlipidemia, diabetes mellitus, and obesity; and 2) specific pharmacologic therapy such as insulin sensitizers, antioxidants, or cytoprotective agents. Newer thiazolidinediones, such as rosiglitazone and pioglitazone, have shown promise in the treatment of NASH in pilot studies. However, these agents should not be used in clinical practice until their efficacy and safety are firmly established in larger studies. Despite encouraging initial studies, the recently completed multicenter, randomized, controlled trial failed to show any efficacy for ursodeoxycholic acid in the treatment of NASH. Other agents, such as vitamin E, betaine, probucol, and atorvastatin, have been explored as therapeutic agents for NASH. However, none of these studies have shown convincingly their utility in the treatment of NASH. Attempts to identify optimal therapy for patients with NASH are being vigorously pursued by the research community and important advances are expected within next several years. Until then, subjects should be advised to avoid alcohol, lose weight, and exercise regularly, and meticulous attention should be paid to the control of their risk factors such as diabetes and hyperlipidemia.