Photomicrograph of stroke-damaged tissue with gel (explained in text).
Image credit: UCLA Health
A stroke occurs when blood supply to a certain part of the brain is significantly reduced, resulting in brain cell death.
Following a stroke, many people will be left with cognitive impairments, motor impairments, or both because of the brain tissue that is destroyed in the process.
In fact, stroke is the leading cause of long-term disability in the United States.
Unlike most other tissues in the body, the brain cannot regenerate; once brain tissue dies, it is absorbed, leaving a cavity that is not refilled.
For many years now, researchers have been trying to find ways to encourage the central nervous system to regenerate — but this has proven challenging.
New approach to stroke damage
Recently, researchers from the University of California, Los Angeles set about the problem using a novel, bioengineered gel. They were led by Dr. Tatiana Segura — now a professor at Duke University in Durham, NC — who created the innovative gel.
The compound is designed to thicken once it enters the brain, acting as a scaffolding for fresh neuronal and vascular growth.
The gel contains compounds intended to stimulate the growth of blood vessels. It also contains anti-inflammatory compounds. This is important because inflammation causes scarring, which hinders new growth.
Using a mouse model of stroke, they squirted the gel into the cavities left by stroke damage. At the 16-week mark, they assessed the cavities for activity and new growth.
They discovered that the gel was slowly absorbed into the body, and regions that had previously been empty spaces were now filled with new tissue. The findings were recently published in the journal Nature Materials.
"This study indicated that new brain tissue can be regenerated in what was previously just an inactive brain scar after stroke."
Dr. S. Thomas Carmichael, researcher
The image at the top of the article is a photomicrograph. It shows new tissue growing into the gel-filled cavity in a stroke-damaged mouse brain.
The red tubes are blood vessels, the green strings are axons — which grow along the blood vessels as they creep into the cavity — and the blue spots are cell nuclei.
When assessing the mice's recovery, the scientists found that motor behavior improved in the mice that had been treated with the gel. However, it is not exactly clear how this improvement was achieved.
Segura explains, "The new axons could actually be working, or the new tissue could be improving the performance of the surrounding, unharmed brain tissue."
The findings are exciting, although preliminary. Of course, more work will need to be done on a much larger scale — but, in principle, this could be a gamechanger.
Carmichael and Segura are eager to continue testing their gel in new situations. For instance, the new study used a mouse model that replicates an intervention roughly 5 days after a stroke.
Next, they want to examine how the gel might perform in brain tissue that was injured longer ago.