Recent breakthroughs in the field of stem cell therapy have brought hope to the treatment of mental diseases. Animal experiments and clinical studies have shown that transplantation of mesenchymal stem cells (MSCs) has a positive effect on the treatment of autism spectrum disorder (ASD). However, the therapeutic efficacy of the MSC transplants was primarily associated with the signals and molecules secreted by the MSCs. Exosomes, for example, the secreted organelles from MSCs, carry bioactive molecules of the MSCs that are essential for the therapeutic effects in ASD treatment. This then inspires us to explore the intranasal delivery of MSC exosomes to brain tissues for the treatment of ASD. Exosomes from human umbilical cord mesenchymal stem cells (hUC-MSCs) that efficiently enter the brain tissue through the intranasal route restore the social ability of the mice and correct the repeated stereotyped behaviors and other abnormal phenotypes in the offspring of valproic acid (VPA)-treated mice, which show autism-like symptoms. The therapeutic efficacy can be attributed at least partially to the anti-inflammatory effect of the MSC exosomes. This work thereby reports brain-specific delivery of hUC-MSC exosomes, as a cell-free therapy to relieve autism-related phenotypes, providing a promising direction for the treatment of mental development disorders.
Keywords: autism spectrum disorder; exosome; human umbilical cord mesenchymal stem cells; inflammation; intranasal.