Stem cell-based therapies show promise as treatments for neurodegenerative diseases, including Alzheimer’s. However, transplanting stem cells into the brain carries considerable risks. A recent study found that a nasal spray that delivered neural stem cell extracellular vesicles—tiny particles that carry proteins and genetic material—reduced inflammation and improved brain function in a mouse model of Alzheimer’s disease, offering a safer, less risky approach.

Researchers used neural stem cell-derived extracellular vesicles created from induced pluripotent stem cells. They administered the vesicles via nasal spray to three-month-old Alzheimer’s model mice. Then, they tracked the vesicles' interaction with brain cells, focusing on microglia and astrocytes, and analyzed gene activity, brain pathology, and behavioral changes.

They found that the vesicles reduced inflammatory activity in brain cells, decreased levels of amyloid-beta plaques and phosphorylated tau (hallmarks of Alzheimer’s), and improved memory and mood in the mice. These effects persisted for at least two months after treatment without impairing the brain’s immune processes and protein clearance.

These findings suggest that a nasal spray containing stem cell-derived extracellular vesicles offers a promising new therapy for Alzheimer’s disease, targeting inflammation and preserving brain function while avoiding the risks of direct stem cell transplantation. Other research demonstrates the effectiveness of stem cell therapies for eye diseases. Learn more in this clip featuring Dr. David Sinclair.