Impaired cardiac function in leptin-deficient mice.

The obesity gene product leptin plays an important role in the physiologic regulation of appetite and energy balance. Plasma leptin levels correlate closely with body fat storage and may respond to changes in energy expenditure. Recent evidence has implicated a direct cardiac regulatory action of leptin in addition to its well-established metabolic properties. Compelling evidence has indicated a link between abnormal leptin levels (hyper- or hypoleptinemia) and cardiac dysfunction. The leptin-deficient ob/ob mice have been used as a model for insulin resistance, obesity, and type 2 diabetes. Leptin replenishment has been shown to restore the depressed cardiac contractile function in ob/ob mice, indicating a permissive role of leptin in cardiac function. The precise role of leptin or leptin deficiency on cardiac health has not been fully elucidated. This article briefly reviews leptin's physiologic role in cardiomyocyte structure and function and how leptin deficiency or disrupted signaling may trigger cardiac functional and morphologic abnormalities.