Injecting Stem Cells Directly Into the Brain Lets Stroke Patients Walk Again

Previously immobile stroke patients might be able to walk again, thanks to a promising new technique that endows the brain with greater power to repair itself.

Scientists have long thought that when a stroke damages regions of a person’s brain that control motor skills, the affected brain circuits can’t be repaired because they have permanently died out. But recent clinical trials suggest that we may need to shift our understanding. Gary Steinberg, a neurosurgeon from Stanford University and one of the researchers involved in the trials, says that these circuits could instead be inhibited, and therefore capable of becoming disinhibited.

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Paralysis resulting from stroke might not be as permanent as it seems.

The two trials, conducted separately by SanBio and the United Kingdom-based company ReNeuron, demonstrated how stem cell injections into patients’ brains resulted in improved motor function and coordination. Research into stem cells—undifferentiated cells capable of giving rise to more specialized types—has skyrocketed in recent years. They’ve even shown incredible potential for combatting paralysis; for example, the so-called “smell cell” transplant helped one man walk after a severe spinal cord injury.

Before the stem cell injections, the enrolled patients’ previous improvements in mobility had slowed since suffering a stroke. Remarkably, the stem cells revived the brain’s healing process, allowing one patient, who previously could only move one thumb, to walk once again.

Here’s Andy Coghlan, reporting for New Scientist:

All patients in the latest trial showed improvements. Their scores on a 100-point scale for evaluating mobility—with 100 being completely mobile—improved on average by 11.4 points, a margin considered to be clinically meaningful for patients. “The most dramatic improvements were in strength, coordination, ability to walk, the ability to use hands and the ability to communicate, especially in those whose speech had been damaged by the stroke,” says Steinberg.

During both trials, researchers created a small hole in the patients’ skulls that directly led to the damaged portions of the brain responsible for motor movement. SanBio and ReNeuron researchers then injected stem cells taken from the bone marrow of donors and from the brains of aborted fetuses, respectively.

The team hypothesized that these stem cells could alter this region of the brain to perform more like a baby’s than an adult’s brain. Because of this, the brain would have a greater capacity for repair.

SanBio and ReNeuron have already planned to use this technique on more patients. Though these results are hopeful, the U.K. Stroke Association emphasizes the necessity for additional research to confirm these findings and assure the optimal location and dose of injections. But with more than 30 similar trials already in progress, ongoing research and results should be available soon.

Though time will tell whether these treatment methods pan out, these initial results hold a great deal of promise, not only for stroke treatment, but also for the remarkable potential stem cells hold across the field of medicine.