Research

Researchers reversed Alzheimer’s disease in mice by restoring the blood-brain barrier’s ability to clear toxic proteins from the brain.

Context

The brain has a protective barrier that acts like a gatekeeper, controlling what gets in and out while removing waste. In Alzheimer’s patients, some scientists believe this barrier becomes clogged with a toxic plaque and stops working properly, allowing harmful proteins called amyloid beta to build up. These proteins prevent brain cells from communicating with each other. For decades, scientists have debated whether amyloid beta buildup directly causes Alzheimer's or is simply associated with the disease, with some researchers questioning whether removing amyloid alone can reverse cognitive decline.

Breakthrough Treatment

On Monday, a team of researchers from Spain and China published their research in Signal Transduction and Targeted Therapy, showing how they reduced Alzheimer’s disease in mice.

The team developed specialized nanoparticles – extremely small engineered particles – that restore the blood-brain barrier’s natural clearing function. The nanoparticles are injected into the bloodstream, where they travel to the brain barrier, attach to it, and restart the natural process that removes waste from the brain. Unlike traditional treatments that use nanoparticles to deliver medicine, these nanoparticles work as the medicine themselves.

Rapid Results

The researchers tested the therapy on mice bred to develop Alzheimer’s-like symptoms. “Only one hour after the injection, we observed a reduction of 50-60 per cent in amyloid beta amount inside the brain,” said one of the researchers. 

The team tracked the animals’ behavior and memory over several months to measure the treatment’s effects.

Long-Term Recovery

In one experiment, researchers treated a 12-month-old mouse – similar to a 60-year-old human – and checked on it six months later. The mouse, now 18 months old (like a 90-year-old human), had regained the memory and behavior of a healthy mouse. The treatment works by jump-starting the blood-brain barrier’s waste-removal system, which then continues clearing out harmful proteins on its own.

Human Implications

The researchers said the treatment offers hope for new Alzheimer’s therapies that fix the brain’s cleaning system rather than directly targeting brain cells.

The research professor who led the study explained that once the barrier starts working properly again, it keeps removing harmful proteins and allows the brain to heal itself. More research is needed to see if this approach will work in humans.