Mesenchymal Stem Cell-Derived Exosomes in Post-Infarction Myocardial Repair

Background: Myocardial infarction (MI) leads to irreversible cardiomyocyte loss, inflammation, and fibrotic remodeling, ultimately contributing to progressive heart failure. While mesenchymal stem cells (MSCs) have shown promise in cardiac regeneration, their therapeutic benefits are increasingly attributed to paracrine mechanisms—particularly the release of extracellular vesicles such as exosomes. MSC-derived exosomes are nanosized vesicles enriched with bioactive cargo, including microRNAs, proteins, and lipids, capable of modulating key processes in myocardial repair without the limitations of cell-based therapies. Methods and Results: This review synthesizes current evidence on the isolation, characterization, and functional application of MSC-derived exosomes in experimental models of post-infarction myocardial repair. Exosomes derived from bone marrow, adipose tissue, and umbilical cord MSCs have demonstrated cardioprotective effects through multiple mechanisms, including promotion of angiogenesis, suppression of apoptosis, attenuation of inflammatory signaling, and stimulation of endogenous repair pathways. Specific microRNAs—such as miR-21, miR-126, and miR-210—play central roles in regulating endothelial cell proliferation, fibroblast activation, and macrophage polarization. Preclinical studies report improved ejection fraction, reduced infarct size, and enhanced capillary density following exosome administration. Bioengineering strategies, such as exosome surface modification, controlled release systems, and targeted delivery via cardiac homing peptides, are being developed to enhance therapeutic efficacy. Conclusion: MSC-derived exosomes represent a cell-free, immunomodulatory, and reparative strategy for myocardial regeneration after infarction. Their ability to deliver cardioprotective signals in a minimally invasive and scalable format positions them as a promising platform for next-generation cardiac therapeutics. Further research is needed to optimize manufacturing, dosing, and delivery approaches to enable clinical translation.