Stem cell therapy improves brain activity after stroke

Every 40 seconds, someone in the United States suffers a stroke. Among survivors of ischemic strokes – the most common type – only about 5% fully recover. The rest often experience long-term problems such as weakness, chronic pain, or epilepsy.

Now, a recent study from Gladstone Institutes and the regenerative medicine company SanBio offers new hope. Scientists have shown that a stem cell-derived therapy can restore normal brain activity after a stroke – even when administered a month later.

Revolutionary approach to stroke recovery

Most current stroke treatments must be given within hours to be effective. However, the new stem cell therapy showed benefits in rats long after the initial stroke.

“There are currently no treatments that can be given weeks or months after a stroke to prevent long-term symptoms, so this is incredibly exciting,” said Dr. Jeanne Paz, the lead investigator of the study.

“Our findings suggest that this timepoint is not too late to intervene and make a difference.”

For over a decade, researchers have explored modified stem cells to treat stroke and traumatic brain injuries. Clinical trials indicated that these cells helped some patients regain movement. However, scientists were unsure how these improvements occurred in the brain.

This new study is the first to document the direct effects of stem cells on brain activity. It paves the way for refining cell therapy and developing other brain-targeting treatments.

Addressing brain hyper-excitability

Ischemic strokes block blood flow to the brain, depriving cells of oxygen and nutrients. This results in cell death and altered brain activity.

Researchers, including Paz, have studied how strokes cause lasting damage, such as epilepsy. They found that damaged brain areas become hyperexcitable – sending excessive signals to other parts of the brain.

“This hyperexcitability has been linked to movement problems and seizures, but no therapies have been developed to effectively reverse it,” said Paz, who is also an associate professor at UC San Francisco and a member of the International Post-Stroke Epilepsy Consortium.

Stem cells in stroke-affected brains

For the investigation, the researchers injected modified human stem cells into the brains of stroke-affected rats a month after their stroke. They then monitored brain activity and analyzed cellular responses.

The results were remarkable. The stem cell treatment reduced hyperexcitability and restored normal neural function. It also increased proteins and cells essential for brain repair.

Surprisingly, even though fewer than 1% of the transplanted cells remained in the rats’ brains after a week, their effects persisted.

“It seems these cells are essentially jump-starting the brain’s own repair processes,” said Dr. Barbara Klein, a principal scientist at SanBio and first author of the study. “This may open a new window of opportunity for the brain to recover, even in the chronic phase after a stroke.”

Blood tests revealed another key finding. Stroke changes blood chemistry, increasing molecules linked to inflammation and poor brain health. The stem cell therapy restored these levels to normal.

“These effects were so striking that we repeated the experiments over and over because we didn’t quite believe them,” said Dr. Paz.

“It’s incredible that you can inject something short-lived into the brain and have lasting effects – not only on brain hyperexcitability, but also in the rest of the body.”

Stem cell therapy and stroke recovery

The study suggests that stroke survivors – even those in the chronic phase – may still have hope for recovery because of stem cell therapy.

“This tells us there may be hope for chronic brain injury patients who, until now, did not have any treatment options,” said Dr. Agnieszka Ciesielska, a postdoctoral researcher in Paz’s lab and co-first author of the study.

However, more research is needed to confirm that reducing hyperexcitability translates to symptom relief in patients. If so, scientists could develop drugs that replicate the effects of stem cells.

The specific cells used in the study, known as SB623, were developed by SanBio for treating neurological motor deficits caused by stroke and traumatic brain injury.

Japan recently approved the therapy for chronic motor paralysis following traumatic brain injury. SanBio is also seeking FDA approval for broader use.

This study from Gladstone Institutes marks a significant step in understanding and treating post-stroke brain damage. If further research confirms the findings, stem cell therapy could transform stroke recovery – offering hope to millions who currently face lifelong disabilities.

The study is published in the journal Molecular Therapy.

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