As Alzheimer’s disease continues to impact a record seven million Americans, scientists at the University of California, Irvine, have announced a potentially revolutionary treatment using stem cells to reprogram the brain’s own immune system. The approach, tested in mice, has shown promising signs of reversing key symptoms of dementia, including inflammation and cognitive decline.

The therapy focuses on microglia, immune cells found in the central nervous system that act as the brain’s primary line of defense. Researchers used CRISPR gene-editing technology to reprogram these cells to produce an enzyme called neprilysin, known to break down toxic beta-amyloid plaques—protein clumps that accumulate in Alzheimer’s patients and are believed to contribute to neurodegeneration.

The results were impressive: in mouse models, the edited microglia preserved neurons, reduced inflammation, cleared beta-amyloid buildup, and even reversed signs of neurodegeneration.

“Delivering biologics to the brain has long been a major challenge because of the blood-brain barrier,” said study co-author Mathew Blurton-Jones, a neurobiology professor at UCI. “We’ve developed a programmable, living delivery system that gets around that problem by residing in the brain itself and responding only when and where it’s needed.”

The treatment not only proved highly targeted, but the researchers believe it could be adapted to tackle other central nervous system conditions as well. Robert C. Spitale, a professor of pharmaceutical sciences at UCI and co-author of the study, said the implications could be far-reaching: “Instead of using synthetic drugs or viral vectors, we’re enlisting the brain’s immune cells as precision delivery vehicles.”

Dr. Joel Salinas, a neurologist at NYU Grossman School of Medicine who was not involved in the study, called the findings “an impressive proof of concept,” praising the precision of the approach and its potential to minimize harm to healthy brain tissue. “Instead of releasing treatment throughout the brain, these modified cells activate only where disease-related damage is happening,” Salinas explained. “That could reduce side effects and focus therapeutic effects where they’re needed most.”

The new therapy, funded by the National Institutes of Health, was published in the journal Cell Stem Cell. The researchers also received support from the California Institute for Regenerative Medicine and the Cure Alzheimer’s Fund.

Looking ahead, the scientists plan to move toward clinical trials in humans. Future studies could use patient-specific stem cells to reduce the risk of immune rejection. Courtney Kloske, Ph.D., of the Alzheimer’s Association, praised the research as “promising and hopeful,” but cautioned that “additional research is needed to determine how this type of drug delivery mechanism could impact individuals living with or at risk for Alzheimer’s.”

If proven safe and effective in humans, the therapy could represent a massive leap forward not just for Alzheimer’s care, but also for other neurodegenerative diseases like multiple sclerosis and even brain cancer.

For now, experts say the discovery marks a critical step forward in the search for smarter, more targeted Alzheimer’s treatments that go beyond symptom management—and get to the heart of the disease itself.