Hepatic steatosis in obese patients: clinical aspects and prognostic significance

SUMMARY Non-alcoholic fatty liver disease is a clinico-pathological condition of emerging identity and importance, now recognized as the most common cause of abnormal liver tests. It is characterized by a wide spectrum of liver damage: simple steatosis may progress to advanced fibrosis and to cryptogenic cirrhosis through steatohepatitis, and ultimately to hepatocellular carcinoma. Obesity is the single most significant risk factor for the development of fatty liver, both in children and in adults; obesity is also predictive of the presence of fibrosis, potentially progressing to advanced liver disease. From a pathogenic point of view, insulin resistance has a central role in the accumulation of triglycerides within the hepatocytes and in the initiation of the inflammatory cascade. Chronic hepatocellular injury, necroinflammation, stellate cell activation, progressive fibrosis and ultimately, cirrhosis may be initiated by peroxidation of hepatic lipids and injury-related cytokine release. In the last few years several pilot studies proved that treatments with insulin-sensitizing agents, antioxidants or cytoprotective drugs may be useful, but there is no evidence-based support from randomized clinical trials. Lifestyle modifications (e.g., diet and exercise) to reduce obesity remain the mainstay of prevention and treatment of a disease which poses a large number of persons at risk of advanced liver disease in the next future.