Role of adiponectin in the pathogenesis and treatment of nonalcoholic fatty liver disease

Adiponectin is an insulin-sensitizing adipokine possessing multiple beneficial effects on nonalcoholic fatty liver disease. This adipokine is secreted from adipocytes into the circulation as three oligomeric isoforms: trimer, hexamer and the high molecular weight (HMW) oligomeric complex. Adiponectin binds to its receptor to exert its effects on target organs. The hepato-protective activities of adiponectin have been demonstrated by many clinical and experimental studies. Decreased level of serum adiponectin represents an independent risk factor for (NAFLD and liver dysfunction in humans. In animals, elevation of circulating adiponectin by either pharmacological or genetic approaches leads to a significant alleviation of hepatomegaly, steatosis and necro-inflammation associated with various liver diseases. In adiponectin knockout mice, there is a pre-existing condition of hepatic steatosis and mitochondrial dysfunction, which might contribute to increased vulnerability of these mice to secondary liver injuries induced by obesity and other conditions. This review aims to summarize the recent advances in research of the structural, molecular and cellular mechanisms underlying the hepato-protective properties of adiponectin.