Exosomes are extracellular vesicles of endosomal origin which have emerged as 
key mediators of intercellular communication. All major cardiac cell 
types-including cardiomyocytes, endothelial cells, and fibroblasts-release 
exosomes that modulate cellular functions. Exosomes released from human cardiac 
progenitor cells (CPCs) are cardioprotective and improve cardiac function after 
myocardial infarction to an extent comparable with that achieved by their parent 
cells. Cardiac progenitor cell-derived exosomes are enriched in cardioprotective 
microRNAs, particularly miR-146a-3p. Circulating exosomes mediate remote 
ischaemic preconditioning. Moreover, they currently are being investigated as 
diagnostic markers. The discovery that cell-derived extracellular signalling 
organelles mediate the paracrine effects of stem cells suggests that cell-free 
strategies could supplant cell transplantation. This review discusses emerging 
roles of exosomes in cardiovascular physiology, with a focus on cardioprotective 
activities of CPC-derived exosomes.