Regenerative effects of myogenic gene transfected MSC derived exosomes on radiation esophagitis

Radiation esophagitis is a common adverse effect of radiotherapy for head and neck cancers, and is marked by irreversible damage and fibrosis of esophageal muscle tissue. Although mesenchymal stem cell (MSC) therapy is emerging as a promising approach for tissue regeneration, clinical translation remains challenging due to issues with cell viability and differentiation in vivo. This study evaluates the regenerative efficacy of exosomes derived from MSCs transfected with myogenic genes (MyoD, Myogenin, Myf6, referred to as Myo-MIX) using a murine model of radiation-induced esophageal fibrosis.

Human adipose-derived MSCs were transfected with Myo-MIX plasmids by electroporation, and exosomes were collected from conditioned media using ExoQuick. Nanoparticle tracking analysis and transmission electron microscopy were employed to characterize exosomal size and morphology. A mouse model of localized radiation-induced esophageal injury (10 Gy × 2 fractions) was generated and followed by intramuscular administration of Myo-MIX exosomes. Regenerative and anti-fibrotic outcomes were examined through Masson's trichrome staining, immunohistochemistry (α-SMA, Calponin, CD68), and quantitative RT-PCR.

Treatment with Myo-MIX exosomes resulted in a pronounced decrease in fibrosis and inflammatory response compared to PBS-treated controls and naïve MSC-exosome groups. Enhanced restoration of muscular architecture was observed, accompanied by elevated expression of Calponin and α-SMA, and a reduction in CD68 + macrophage infiltration. Gene expression profiling indicated increased levels of myogenic and anti-fibrotic markers in the Myo-MIX exosome-treated group.

Exosomes from myogenic gene-transfected MSCs significantly enhance esophageal muscle regeneration and attenuate fibrosis after radiation-induced damage. This cell-free therapeutic approach holds potential as a novel and practical strategy for addressing radiation esophagitis in patients receiving radiotherapy for head and neck malignancies.