# Mesenchymal Stem Cell-Derived Extracellular Vesicles in Myocardial Ischemia–Reperfusion Injury: A Comprehensive Review

## TL;DR

This review explores how extracellular vesicles from mesenchymal stem cells protect heart muscle after blood flow is restored following a heart attack.

## Contribution

The paper provides a comprehensive overview of the mechanisms by which mesenchymal stem cell-derived extracellular vesicles mediate cardioprotection in ischemia–reperfusion injury.

## Key findings

- Mesenchymal stem cell-derived extracellular vesicles modulate multiple signaling pathways, including PI3K/PKB and STAT3.
- These vesicles preserve mitochondrial function and reduce oxidative stress and inflammation in injured heart tissue.
- The vesicles' cargo includes microRNAs and proteins that coordinate protective effects rather than acting on single targets.

## Abstract

Restoring blood flow to the heart after a heart attack is essential to save tissue, but it can also trigger additional injury to heart muscle cells. This paradoxical damage is driven by several biological mechanisms, including excessive oxidative stress, disturbances in calcium balance, failure of energy production, inflammation, and dysfunction of mitochondria, the structures responsible for supplying energy to cells. Current therapies do not specifically target these processes. Mesenchymal stem cells have shown protective effects in experimental models, largely through the release of extracellular vesicles, which are small membrane-bound particles that transfer biological signals between cells. In this review, we describe how extracellular vesicles derived from mesenchymal stem cells influence key molecular pathways involved in heart injury after blood flow restoration. These vesicles deliver regulatory molecules that reduce programmed cell death, preserve mitochondrial function, support cellular energy metabolism, and modulate inflammatory responses in the injured heart. Rather than acting on a single target, extracellular vesicles coordinate multiple protective mechanisms simultaneously. A clearer understanding of these biological actions may support the development of new therapeutic strategies aimed at limiting heart damage after a heart attack and improving long-term cardiac recovery through cell-free, mechanism-based interventions.

Myocardial ischemia–reperfusion injury remains a major unresolved challenge in cardiovascular medicine. Although timely restoration of blood flow is essential to limit ischemic damage, reperfusion triggers a complex network of maladaptive biological responses, including oxidative stress, calcium overload, mitochondrial dysfunction, metabolic impairment, and sterile inflammation. These processes converge on cardiomyocyte death, adverse ventricular remodeling, and long-term functional deterioration. Mesenchymal stem cells have been widely investigated as cardioprotective agents; however, accumulating evidence indicates that their beneficial effects are predominantly mediated by paracrine mechanisms. Among these, extracellular vesicles released by mesenchymal stem cells have emerged as key biological effectors. Experimental studies demonstrate that mesenchymal stem cell–derived extracellular vesicles modulate multiple signaling pathways involved in ischemia–reperfusion injury, including activation of the phosphoinositide 3-kinase (PI3K) and protein kinase B (PKB) axis, regulation of signal transducer and activator of transcription 3 (STAT3) signaling in a cell-specific manner, suppression of nuclear factor kappa B (NF-κB)-driven inflammatory responses, and stabilization of hypoxia-inducible factor-1α (HIF-1α)–dependent adaptive programs. At the subcellular level, these vesicles preserve mitochondrial structure and function, support energy metabolism, regulate mitophagy, and limit oxidative damage. Their molecular cargo, comprising regulatory microRNAs, metabolic enzymes, and stress-response proteins, enables coordinated modulation of survival, inflammatory, and reparative pathways rather than single-target effects. This review synthesizes current experimental evidence on the mechanistic basis of mesenchymal stem cell–derived extracellular vesicle–mediated cardioprotection and discusses their potential as cell-free, mechanism-based therapeutic strategies to limit myocardial ischemia–reperfusion injury.