Effect of administration of mesenchymal stem cell-derived exosomes on facial nerve injury

The facial nerve can be damaged by trauma, inflammation, surgical manipulations, viral infection, or neoplastic diseases. Dysfunction of the facial nerve can cause facial paralysis and other unpleasant symptoms. The gold standard treatment for this condition involves the grafting of normal donor nerve from an uninjured body location, a method limited by tissue availability and inconsistency in size. Therefore, less invasive, and more efficient treatment options are in high demand.

In our previous studies, exosomes derived from bone-marrow mesenchymal stem cells (bm-MSCs) have been shown to promote nerve regeneration following spinal cord injury (SCI). Capable of targeting a specific tissue, exosomes are employed as natural drug delivery vehicles for RNA and proteins. For instance, SCI conditions were substantially improved when exosomes were loaded with phosphatase and tensin (PTEN) homolog small interfering RNA (siRNA).

In this research, we focused on utilizing exosomes as therapeutic tools to target genes relevant to facial nerve regeneration. We started with an in vitro proof-of-concept study to test the regenerative potential of the exosomes on rat and human. Rat neurons were obtained from dorsal root ganglions and human neurons were generated from the human induced pluripotent stem cells. The neuron exposure to bm-MSCs derived exosomes for one day facilitated neurite outgrowth, indicated by significantly higher neurite length in in exosomes-treated neurons. This shows the exosome’s regenerative potential. We are currently exploring the therapeutic potential of exosomes on facial nerve contusion injury in vivo.