Abstract
PURPOSE OF THE REVIEW: The role of leptin in regulating cardiac function is still controversial with conflicting results in clinical and preclinical studies. However, most previous studies have not considered leptin's powerful cardiac effects that are mediated via activation of central nervous system (CNS) leptin receptors (LepRs) which, in turn, elicit major improvements in cardiac metabolism. In this review, we focus mainly on the role of leptin in regulating cardiac function via its CNS LepRs and downstream signaling pathways, such as the brain melanocortin system. RECENT FINDINGS: Studies from our laboratory showed that CNS LepR activation, without raising plasma leptin levels, has remarkable beneficial effects on cardiac metabolism and function that protect the heart during pathological conditions, including heart failure (HF) induced by myocardial infarction (MI). These cardioprotective effects of leptin appear to be mediated by stimulation of CNS proopiomelanocortin neurons and subsequent activation of melanocortin 4 receptors (MC4R) in the brain. Chronic activation of the brain leptin-melanocortin pathway improves cardiac function and metabolism following myocardial infarction. However, the mechanism underlying this brain-heart crosstalk remains unclear and may have important implications for the development of new therapies for MI and HF.