Metabolic Roles of Adiponectin

Adiponectin is an adipocyte-derived secretory protein with a multitude of physiological functions. It has insulin-sensitizing, anti-inflammatory, anti-apoptotic, and angiogenic properties that are critical for the maintenance of metabolic health during high-fat diet challenges. Its plasma levels are generally inversely related to fat mass, which is rarely seen for adipokines whose local or systemic levels, in general, are directly proportional to adipose tissue mass. Due to these unique properties, adiponectin serves as an excellent biomarker for metabolic health-related pathophysiological changes associated with insulin resistance and cardiovascular disease. Striking clinical correlations have been reported with elevated levels of adiponectin being associated with improved systemic insulin sensitivity, particularly as it relates to insulin action in the liver. A number of mouse models implicate the protein more directly in metabolic improvements. Mice lacking adiponectin are more insulin resistant in the context of high-fat diet exposure, whereas mice overexpressing adiponectin are highly protected under those conditions. The protein acts on numerous additional cell types with the net result that it enhances the 'metabolic flexibility' of the individual by enabling it to handle large lipid loads more effectively.