Adropin is a novel membrane-bound protein, which contains 76 amino acids and isencoded by the energy homeostasis-associated gene.5 It is expressed predominantly in the liver, brain,coronary arteries, vascular endothelium and heart (all layers).6 A recent study reported thatelevated plasma levels of adropin in heart failure with reduced ejection fractionpatients were positively correlated with disease severity, as classified by the NewYork Heart Association (NYHA).7Irisin is a thermogenic protein, which is expressed in adipose tissue, cardiacmuscle, heart and other peripheral tissues. Here, ENHO is linked to heart failure.