When someone has a stroke, the blood flow to the brain is blocked. This kills some nerve cells and injures others. The damaged nerve cells are unable to communicate with other cells, which often results in people having impaired speech or movement.
While ischemic and hemorrhagic strokes affect large blood vessels and usually produce recognizable symptoms there’s another kind of stroke that is virtually silent. A ‘white’ stroke occurs in blood vessels so tiny that the impact may not be noticed. But over time that damage can accumulate and lead to a form of dementia and even speed up the progression of Alzheimer’s disease.
Now Dr. Tom Carmichael and his team at the David Geffen School of Medicine at UCLA have developed a potential treatment for this, using stem cells that may help repair the damage caused by a white stroke. This was part of a CIRM-funded study (DISC2-12169 – $250,000).
Instead of trying to directly repair the damaged neurons, the brain nerve cells affected by a stroke, they are creating support cells called astrocytes, to help stimulate the body’s own repair mechanisms.
In a news release, Dr. Irene Llorente, the study’s first author, says these astrocytes play an important role in the brain.
“These cells accomplish many tasks in repairing the brain. We wanted to replace the cells that we knew were lost, but along the way, we learned that these astrocytes also help in other ways.”
The researchers took skin tissue and, using the iPSC method (which enables researchers to turn cells into any other kind of cell in the body) turned it into astrocytes. They then boosted the ability of these astrocytes to produce chemical signals that can stimulate healing among the cells damaged by the stroke.
These astrocytes were then not only able to help repair some of the damaged neurons, enabling them to once again communicate with other neurons, but they also helped another kind of brain cell called oligodendrocyte progenitor cells or OPCs. These cells help make a protective sheath around axons, which transmit electrical signals between brain cells. The new astrocytes stimulated the OPCs into repairing the protective sheath around the axons.
Mice who had these astrocytes implanted in them showed improved memory and motor skills within four months of the treatment.
And now the team have taken this approach one step further. They have developed a method of growing these astrocytes in large amounts, at very high quality, in a relatively short time. The importance of that is it means they can produce the number of cells needed to treat a person.
“We can produce the astrocytes in 35 days,” Llorente says. “This process allows rapid, efficient, reliable and clinically viable production of our therapeutic product.”
The next step is to chat with the Food and Drug Administration (FDA) to see what else they’ll need to do to show they are ready for a clinical trial.
The study is published in the journal Stem Cell Research.