Background: Neurodegenerative diseases comprise a group of disorders for which no treatment
is available till date. Stem cell based therapy offers great hope and promise. However, stem cell
transplantation is associated with certain disadvantages like poor targeted migration, engraftment and
survival of the transplanted cells.
Material & Method: Exosomes, a type of extracellular membrane vesicle released by all cell types including
stem cells, offer an alternative to stem cell transplantation. Exosome carry a wide array of biomolecules
and are implicated in exhibiting substantial benefits in the repair/regeneration of the injured
tissue. Thus, exosomes offer an alternative therapeutic approach as a substitute of cell transplantation.
In order to utilize exosomes for therapeutic purpose, it is essential to evaluate the appropriate passage
number and the dosage to avoid possible cytotoxic effects. Here, we isolated exosomes from different
passages of rat bone marrow mesenchymal stem cells (BM-MSC) and analysed the neuroprotective
potential of BM-MSC exosomes in an in vitro model of excitotoxicity.
Result: Our results demonstrated that the exosomes isolated from early passage of rat BM-MSC exhibited
more efficient neuroprotective potential as opposed to later passages derived exosomes.
Furthermore, the neuroprotective efficacy of exosome is dosage dependent. i.e. the lower dosage of
exosomes was found to be neuroprotective, whereas higher dosage of exosomes (from later passages)
was found to be detrimental to neurons. The early passage derived exosomes protected neurons
through anti-apoptotic, anti-necrotic and anti-oxidant mechanisms.
Conclusion: Our study suggests that adult stem cells derived exosomes could be a potential therapeutic
agent to confer neuroprotection in neurodegenerative diseases like Alzheimer's disease.