24 Protecting the Heart at a Distance: Exosomes for nano-sized Cardioprotection

Exosomes: promising sacks for treating ischemic heart disease?

Ischemic heart disease(IHD) is the leading cause of death worldwide. Despite the development of continuously improving therapeutic strategies, morbidity and mortality of patients with IHD remain relatively high. Exosomes are a subpopulation of vesicles that are universally recognized as major mediators in intercellular communication. Numerous preclinical studies have shown that these tiny vesicles were protective in IHD, through such actions as alleviating myocardial ischemia-reperfusion injury, promoting angiogenesis, inhibiting fibrosis, and facilitating cardiac regeneration. Our review focused on these beneficial exosome-mediated processes. In addition, we discuss in detail how to fully exploit the therapeutic potentials of exosomes in the field of IHD. Topics include identifying robust sources of exosomes, loading protective agents into exosomes, developing heart-specific exosomes, optimizing isolation methods, and translating the cardioprotective effects of exosomes into clinical practice. Finally, both the advantages and disadvantages of utilizing exosomes in clinical settings are addressed.

Therapeutic Effects of Ischemic-Preconditioned Exosomes in Cardiovascular Diseases

Despite years of researches, cardiovascular disease (CVD) remains the most common cause of death around the world. Lots of studies showed that by pretreating with short nonfatal ischemia in in situ organ or distant organ, one could develop tolerance to the following fatal ischemia. The process is called ischemic preconditioning (IPC). IPC prepare the heart for damage by producing inflammatory signals, miRNA, neuro system stimulation and exosomes. Among them, exosomes have been gaining increasing interest since it is characterized by its capability to carry information and its specific ligand-receptor system. Here we will discuss IPC induced exosomes and its protective effects during ischemic heart disease.

Remote ischemic conditioning

In remote ischemic conditioning (RIC), brief, reversible episodes of ischemia with reperfusion in one vascular bed, tissue, or organ confer a global protective phenotype and render remote tissues and organs resistant to ischemia/reperfusion injury. The peripheral stimulus can be chemical, mechanical, or electrical and involves activation of peripheral sensory nerves. The signal transfer to the heart or other organs is through neuronal and humoral communications. Protection can be transferred, even across species, with plasma-derived dialysate and involves nitric oxide, stromal derived factor-1α, microribonucleic acid-144, but also other, not yet identified factors. Intracardiac signal transduction involves: adenosine, bradykinin, cytokines, and chemokines, which activate specific receptors; intracellular kinases; and mitochondrial function. RIC by repeated brief inflation/deflation of a blood pressure cuff protects against endothelial dysfunction and myocardial injury in percutaneous coronary interventions, coronary artery bypass grafting, and reperfused acute myocardial infarction. RIC is safe and effective, noninvasive, easily feasible, and inexpensive.