Researchers at the University of Georgia have developed a new stem-cell-based treatment for strokes. When tested in animal models, the technique was found to reduce brain damage and help the brain heal itself faster, and the results have been promising enough that human clinical trials may follow as soon as next year.

According to the CDC, strokes affect almost 800,000 people every year in the US, and of those about 140,000 die as a result – making it the fifth-leading cause of death in the country. Survivors usually face a long period of rehabilitation, and in severe cases permanent brain damage can follow. Previous research into possible stroke treatments has included existing anti-inflammatory drugs, peptides found in spider venom, and a custom-made catheter for removing clots.

A particularly promising line of treatment involves stem cells. A few years ago, a London study used a certain set of CD34+ stem cells to trigger the growth of new brain tissue and blood vessels. Later, a Stanford study managed to restore mobility in the limbs of stroke victims after injecting stem cells into the brain.

The new study, conducted by researchers from the University of Georgia's Regenerative Bioscience Center and spinout startup ArunA Biomedical, also uses stem cells. Dubbed AB126, the treatment uses exosomes, tiny tube-shaped structures generated by neural stem cells. Since these structures are smaller than cells, they're able to cross certain barriers that cells can't, carrying and delivering multiple doses of regenerative therapeutics to where they're most needed.

"This is truly exciting evidence, because exosomes provide a stealth-like characteristic, invisible even to the body's own defenses," says Steven Stice, lead researcher on the study. "When packaged with therapeutics, these treatments can actually change cell progression and improve functional recovery."

The exosomes (red) are being taken up by the nuclei (blue) of the neurons (green) in the brain of the stroke victims(Credit: University of Georgia)

The researchers tested AB126 on mice, and found that the treatment improved the recovery of motor control and memory in stroke victims. Next, the team compared MRI scans of mice who had been treated with AB126 to stroke-affected animals that hadn't received the treatment. They found that the treatment shrunk the size of the injury by about 35 percent, and halved the amount of brain tissue that was lost as a result of stroke.

"Until now, we had very little evidence specific to neural exosome treatment and the ability to improve motor function," says Stice. "Just days after stroke, we saw better mobility, improved balance and measurable behavioral benefits in treated animal models."

The researchers followed up the study with a test in pigs, and found similar results. Encouraged by that, the team is now preparing for human studies, which are set to kick off in 2019.

The research was published in the journal Translational Stroke Research.

Source: University of Georgia

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