Animal study shows improved survival and maturation of stem cells, integration into brain tissue
Researchers have created a unique mix of cells and supportive molecules that, when injected into the site of stroke in animal models, improves recovery and survival. The mix ture form s a nurturing environment in which stem cells can develop into full - fledged nerve cells, according to findings presented November 18 at Neuroscience 201 4, the annual meeting of the Society for Neuroscience and the world’s largest source of emerging news about brain science and health.
“Stem cells can do more for stroke recovery when they are delivered within a supportive environment,” said senior author Tom Carmichael of the University of California, Los Angeles. “Our approach promoted the survival of transplanted stem cells at the very site of the stroke, which enabled their development into mature brain cells and their integration with other brain tissue.”
Stroke is the leading cause of adult disability, and t here is no medical therapy that consistently promotes brain repair and recovery after stroke. Neural stem cells have moved into clinical trials as a potential remedy for stroke - related brain damage, but their effectiveness has been limited by poor survival of the transplanted cells.
To overcome this limitation, the researchers targeted the actual stroke cavity so that the stem cell transplant would not disrupt normal tissue, and they used a naturally occurring molecular matrix found in the brain, called hyaluronic acid, or HA. HA is important in brain development and is found close to areas of the brain containing stem cells. The researchers combined HA with a mix of growth factors that support ste m cell survival and differentiation, as well as molecules that signal a normal brain environment. Stem cells were encapsulated in this matrix, which assembles itself into a gel once injected into the brain.
Researchers tested the HA gel in mice. One group of mice received the gel a week after an induced stroke. A second group received only stem cells after stroke. Survival was high in first group, and poor in the second. When engulfed in the HA gel, the stem cells not only survived in large numbers, but also differentiated into mature brain cells and gradually integrated into the host brain tissue. The HA gel promoted growth of new blood vessels into the graft, a critical requirement for rebuilding brain tissue. Furthermore, scientists report that the HA gel can be visualized on routine magnetic resonance imaging scanning, achieving an important goal of tracking a brain recovery over time.