[Involvement and role of iron in nonalcoholic steatohepatitis]

Nonalcoholic steatohepatitis (NASH) was described by Ludwig mainly in obese, middle-aged women, often associated with diabetes mellitus and hyperlipidemia. In the recent years, NASH was found to be associated with male, nonobese, nondiabetic patients and with liver iron overload, which led to the hypothesis of iron playing a role in NASH pathogenesis. Increased ferritin with normal transferrin saturation is frequently found in fatty liver patients, but it reflects iron overload only in those patients in which it persists despite an appropriate diet. Insulin resistance hepatic iron overload (IR-HIO) is a new condition of hepatic iron overload, characterized by hyperferritinemia with normal or slightly increased transferrin saturation in the absence of hemochromatotic gene mutations. Although patients with IR-HIO have a high prevalence of insulin resistance-related metabolic disorders, the relationship of IR-HIO and NASH is unclear. Two characteristics allow differentiation of IR-HIO from genetic haemochromatosis: iron overload is heterogeneous from one hepatocyte to another in the periportal area, and sinusoidal iron is distributed throughout the lobule. In IR-HIO, fibrosis develops at a much lower hepatic iron burden than in genetic haemochromatosis, and sinusoidal iron, steatosis and inflammation could represent the histological mark of activity and progression of liver disease in IR-HIO.