New approach could help turn back the clock and reverse damage for stroke patients

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Stroke: courtesy WebMD

Stroke is the leading cause of serious, long-term disability in the US. Every year almost 800,000 people suffer from a stroke. The impact on their lives, and the lives of those around them can be devastating.

Right now the only treatment approved by the US Food and Drug Administration (FDA) is tissue plasminogen activator or tPA. This helps dissolve the blood clot causing most strokes and restores blood flow to the brain. However, to be fully effective this has to be administered within about 3-4 hours after the stroke. Many people are unable to get to the hospital in time and as a result suffer long-term damage, damage that for most people has been permanent.

But now a new study in Nature Medicine shows that might not be the case, and that this damage could even be reversible.

The research, done by a team at the University of Southern California (USC) uses a one-two punch combination of stem cells and a protein that helps those cells turn into neurons, the cells in the brain damaged by a stroke.

First, the researchers induced a stroke in mice and then transplanted human neural stem cells alongside the damaged brain tissue. They then added in a dose of the protein 3K3A-APC or a placebo.

hey found that mice treated with 3K3A-APC had 16 times more human stem-cell derived neurons than the mice treated with the placebo. Those neurons weren’t just sitting around doing nothing. USC’s Berislav Zlokovic, senior author of the paper, says they were actively repairing the stroke-induced damage.

“We showed that 3K3A-APC helps the grafted stem cells convert into neurons and make structural and functional connections with the host’s nervous system. No one in the stroke field has ever shown this, so I believe this is going to be the gold standard for future studies. Functional deficits after five weeks of stroke were minimized, and the mice were almost back to normal in terms of motor and sensorimotor functions. Synapses formed between transplanted cells and host cells, so there is functional activation and cooperation of transplanted cells in the host circuitry.”

The researchers wanted to make sure the transplanted cell-3K3A-ACP combination was really the cause of the improvement in the mice so they then used what’s called an “assassin toxin” to kill the neurons they had created. That reversed the improvements in the treated mice, leaving them comparable to the untreated mice. All this suggests the neurons had become an integral part of the mouse’s brain.

So how might this benefit people? You may remember that earlier this summer Stanford researchers produced a paper showing they had helped some 18 stroke patients, by injecting stem cells from donor bone marrow into their brain. The improvements were significant, including in at least one case regaining the ability to walk. We blogged about that work here

In that study, however, the cells did not become neurons nor did they seem to remain in the brain for an extended period. It’s hoped this new work can build on that by giving researchers an additional tool, the 3K3A-ACP protein, to help the transplanted cells convert to neurons and become integrated into the brain.

One of the other advantages of using this protein is that it has already been approved by the FDA for use in people who have experienced an ischemic stroke, which accounts for about 87 percent of all strokes.

The USC team now hope to get approval from the FDA to see if they can replicate their experiences in mice in people, through a Phase 2 clinical trial.

 

 

 

 

 

 

 

National honor for helping “the blind see”

Those of us fortunate to have good health take so many things for granted, not the least of which is our ability to see. But, according to the World Health Organization, there are 39 million people worldwide who are blind, and another 246 million who are visually impaired. Any therapy, any device, that can help change that is truly worthy of celebration.

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Dr. Mark Humayun: Photo courtesy USC

That’s why we are celebrating the news that Professor Mark Humayun has been awarded the National Medal of Technology and Innovation, the nation’s top technology honor, by President Obama.

Humayun, a researcher at USC’s Keck School of Medicine and a CIRM grantee, is being honored for his work in developing an artificial retina, one that enables people with a relatively rare kind of blindness to see again.

But we are also celebrating the potential of his work that we are funding that could help restore sight to millions of people suffering from the leading cause of blindness among the elderly. But we’ll get back to that in a minute.

First, let’s talk about the invention that has earned him this prestigious award. It’s called the Argus II and it can help people with retinitis pigmentosa, an inherited degenerative disease that slowly destroys a person’s vision. It affects around 100,000 Americans.

The Argus II uses a camera mounted on glasses that send signals to an electronic receiver that has been implanted inside the eye. The receiver then relays those signals through the optic nerve to the brain where they are interpreted as a visual image.

In a story posted on the USC website, USC President C. L. Max Nikias praised Humayun’s work:

“He dreamed the impossible: to help the blind see. With fearless imagination, bold leadership and biomedical expertise, he and his team made that dream come true with the world’s first artificial retina. USC is tremendously proud to be Professor Humayun’s academic home.”

At CIRM we are tremendously proud to be funding the clinical trial that Humayun and his team are running to find a stem cell therapy for age-related macular degeneration (AMD), the leading cause of vision loss in the world.  It’s estimated that by 2020 more than 6 million Americans will suffer from AMD.

Humayun’s team is using embryonic stem cells to produce the support cells, or RPE cells, needed to replace those lost in AMD. We recently produced this video that highlights this work, and other CIRM-funded work that targets vision loss.

In a statement released by the White House honoring all the winners, President Obama said:

“Science and technology are fundamental to solving some of our nation’s biggest challenges. The knowledge produced by these Americans today will carry our country’s legacy of innovation forward and continue to help countless others around the world. Their work is a testament to American ingenuity.”

Which is why we are honored to be partners with Humayun and his team in advancing this research and, hopefully, helping find a treatment for millions of people who dream of one day being able to see again.