Exosomes from MiR-126-Overexpressing Adscs Are Therapeutic in Relieving Acute Myocardial Ischaemic Injury.

Objective: Recent studies have indicated that exosomes play an important role in adipose-derived stem cell (ADSC) transplant-mediated ischaemic heart disease therapy. However, the treatment effect is not obvious. The aim of this study is to investigate whether ADSC-derived exosomes enriched with microRNA (miR)-126 have a more protective effect on acute myocardial infarction (AMI).

Methods: Exosomes were characterized by transmission electron microscopy, and the exosome particles were further examined using nanoparticle tracking analyses. A rat model of myocardial infarction and in vitro model of hypoxia-induced H9c2 myocardial cell injury were established to study the protective mechanism of exosomes from miR-126-overexpressing ADSCs.

Results: The in vitro results showed that exosomes derived from miR-126-overexpressing ADSCs decreased H9c2 myocardial cell injury by reducing inflammation factor expression during hypoxia induction. The miR-126-enriched exosomes also decreased the expression of fibrosis-related proteins of H9c2 cells under hypoxic conditions. Matrigel® and Transwell® assays showed that miR-126-enriched exosomes significantly promoted microvascular generation and migration, respectively. In vivo studies confirmed that exosomes derived from ADSCs significantly decreased the myocardial injury area of infarction, especially after miR-126-enriched exosome treatment. Cardiac fibrosis and inflammatory cytokine expression were also decreased after treatment with miR-126-enriched exosomes. However, blood vessel formation was promoted in the infarction region of AMI rats.

Conclusions: The results suggested that the expression of miR-126-enhanced ADSC-derived exosomes prevented myocardial damage by protecting myocardial cells from apoptosis, inflammation, fibrosis, and increased angiogenesis.