Nasal spray reversed brain aging for the first time

Scientists from the University of Texas have created an experimental nasal spray that, in animal trials, essentially turned back the clock for the aging brain. Just two doses of the drug improved the subjects' memory, suppressed chronic inflammation, and restored normal functioning to brain cells. The results of the study were published in the Journal of Extracellular Vesicles (JEV).

Over the years, chronic low-grade inflammation builds up in the brain — a phenomenon known as neuroinflammatory aging. It is precisely what drives memory decline, the fading ability to learn, and the growing risk of dementia and Alzheimer's disease. However, the authors of the new study are confident that this process can be reversed.

The therapy is based on extracellular vesicles — tiny particles that cells use to exchange molecules. The scientists "loaded" them with microRNA — short molecules capable of regulating gene activity and correcting the functioning of brain cells. The drug was administered through the nose, which allowed it to be delivered directly to the brain, bypassing the blood-brain barrier.

"Intranasal delivery is one of the most exciting parts of our approach. It allows us to target the brain without invasive procedures," emphasized study co-author Mahidhar Kodali.

Once in the brain, the therapy suppressed the activity of inflammatory systems, including the NLRP3 inflammasome and the cGAS-STING signaling pathway, which are recognized as key mechanisms of age-related brain inflammation.

In addition, the treatment restored the function of mitochondria — the cellular "power plants" responsible for energy production. With age, their function declines, making neurons increasingly vulnerable to damage.

"We are essentially restoring the spark to neurons by reducing oxidative stress and restoring mitochondrial function," explained researcher Madhu Leelavathi Narayana.

The results of the memory tests were impressive: after treatment, the animals were better at recognizing familiar objects, noticing changes in their environment, and performed significantly better on tasks compared to the control group. What particularly amazed the scientists was the fact that the effect occurred quickly and lasted for several months — all after just two doses of the drug.

The study's authors believe that in the future, the technology could find applications in slowing age-related cognitive decline, treating dementia, or aiding recovery after stroke.