Injectable hydrogel helps brain tissue regrow after stroke in mice
The brain may be an incredible organ, but it has its weaknesses – for example, it struggles to repair itself after sustaining damage from injury or stroke. Now, researchers from the University of California, Los Angeles (UCLA) have developed an injectable hydrogel that can coax healthy tissue to patch up damage by helping regenerate new brain tissue, nerve fibers and blood vessels.
Strokes strike down almost 800,000 people per year in the US, according to the CDC. It's one of the leading causes of death in the country, but those that do survive often spend the rest of their lives dealing with the physical fallout, facing a long battle to regain mobility. Stem cell treatments are showing promise in several different forms, while other teams have found success using anti-inflammatory drugs or even peptides from spider venom.
The new UCLA study took a different approach. Brain cells killed by a stroke will be absorbed by the body, leaving a cavity where no new blood vessels or neurons will grow. So, the team engineered a hydrogel that could be injected into this gap and act as a scaffold, allowing healthy brain tissue around the injury to patch it up with new tissue. To help things along, the gel contains medications that suppresses inflammation and stimulates the growth of new blood vessels.
In mice tests, the researchers found that new brain tissue, including neuronal connections, had grown in the stroke cavities 16 weeks after the treatment. The animals' motor skills improved too, specifically their ability to reach for food.
"We tested this in laboratory mice to determine if it would repair the brain and lead to recovery in a model of stroke," says Dr. S. Thomas Carmichael, co-author of the study. "The study indicated that new brain tissue can be regenerated in what was previously just an inactive brain scar after stroke."
Over time, the gel was completely absorbed by the body, leaving nothing but the new tissue. Although the results are positive, the researchers haven't yet pinpointed the exact mechanism for the mice's recovered motor skills.
"The new axons could actually be working," says Tatiana Segura, co-author of the study. "Or the new tissue could be improving the performance of the surrounding, unharmed brain tissue."
While the study showed that recovery was possible if treated in the immediate aftermath of the injury, the next steps for the team are to determine whether new brain tissue can be grown much longer after the stroke. In the long run, it's hoped the treatment will be applicable to humans.
The research was published in the journal Nature Materials.