The Interconnections between Obesity, Thyroid function and Autoimmunity: the Multifold Role of Leptin.

Background: There is increasing evidence that changes in thyroid function are associated with obesity, this defined as a chronic low-grade state of inflammation. Meanwhile, recent data have disclosed a relation between obesity and thyroid autoimmunity, with the adipocyte leptin appearing to be the key factor linking these two conditions. Summary: Leptin has variably been implicated in thyroid function, while recent findings suggest that leptin resistance may mitigate leptin deficiency and enhance autoimmunity in obese subjects via mechanisms operating independently of thyroid function. The development of resistance to leptin weight-lowering effects in obesity might well be initiated by activation of inflammatory signalling, which substantially contributes to the derangement of immune response and propagation of autoimmunity in susceptible individuals. Conclusions: Regulation of inflammasome-derived cytokines in obesity is an important step in controlling the trigger of thyroid autoimmunity. The clarification of the pathways will offer innovative therapeutic targets in obesity and thyroid autoimmunity.