Adiponectin has been identified as one of the "adipocytokines" that are derived only from adipose tissue, and are abundantly present in circulating blood. Adiponectin has protective actions in the initiation and progression of atherosclerosis through anti-inflammatory and anti-atherogenic effects. Adiponectin levels are decreased in obesity, type 2 diabetes, and patients with coronary artery disease (CAD). Adiponectin levels were negatively correlated with the CRP levels in patients with CAD. Adiponectin plays a crucial role in the association between obesity, type 2 diabetes, and insulin resistance. Mechanisms explaining the relationship between adiponectin and insulin resistance suggest that adiponectin and tumor necrosis factor (TNF)-alpha inhibited each other's expression and production in adipocytes. Thiazolidinediones, which are insulin-sensitizing agents, increased the production of adiponectin through directly enhancing its gene expression. The C-terminal globular domain of adiponectin may play a central role in the protective effects against atherosclerosis. Adiponectin receptors 1 (AdipoR1) and 2 (AdipoR2) are expressed ubiquitously in most organs, especially in skeletal muscle in AdipoR1, and liver in AdipoR2. With the prospect of future basic and clinical research on the molecular structure-receptor relationship, adiponectin could become a promising target for future investigations in reducing the morbidity and mortality of atherosclerotic disease.
Copyright 2004 Elsevier B.V.