Adiponectin: a key fat-derived molecule regulating inflammation.

Adiponectin is the abundant adipocyte-derived protein with well-established anti-atherogenic and insulin-sensitising properties. Besides these well characterised biological functions, recent evidence supports a strong anti-inflammatory function. Whereas initial studies demonstrated that adiponectin suppresses the production of the potent pro-inflammatory cytokine TNF-alpha, current studies showed that this adipokine also induces various anti-inflammatory cytokines, such as IL-10 or -1 receptor antagonists. These effects are paralleled by various other immune-regulatory properties, such as specific effects on endothelial cell functions. These in vitro effects are directly translated into various animal models of inflammation, demonstrating a potent anti-inflammatory effect for adiponectin. Thiazolidinediones selectively upregulate peroxisome-proliferator-activated receptor-gamma, leading to increased tissue and serum concentrations of adiponectin. Adiponectin has emerged as a key mediator regulating and affecting the balance between fat and inflammation. Therefore, either adiponectin itself or its inducing agents, such as thiazolidinediones, might be of key therapeutic interest in the near future far beyond diseases being associated with insulin resistance.