Fibroblast growth factor 21 in lipid metabolism and non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is one of the most common liver diseases in several developed countries, ranging from simple non-alcoholic fatty liver (NAFL) to non-alcoholic steatohepatitis (NASH) and cirrhosis. Currently, NAFLD has been confirmed to be associated with dyslipidemia, insulin resistance, and pre-diabetes, which are always grouped together as metabolic syndrome. Fibroblast growth factor 21 (FGF21) plays an important role in liver pathophysiology with multiple metabolic functions. Accumulating evidence has shown that FGF21 could directly modulate lipid metabolism and reduce lipid accumulation in hepatocytes through an insulin-independent pathway, thus suppressing the pathogenesis of NAFLD. Furthermore, treatment with FGF21 could obviously reverse NAFLD and synergistically alleviate obesity and counteract insulin resistance. In this review, we summarize the current knowledge of FGF21 and the evidence of FGF21 as an important regulator in hepatic lipid metabolism. The mechanisms by which FGF21 affects the pathogenesis of NAFLD would also be proposed for the further understanding of FGF21.