Injecting modified, human, adult stem cells directly into the brains of chronic stroke patients proved not only safe but effective in restoring motor function, according to the findings of a small clinical trial led by Stanford University School of Medicine investigators.
The patients, all of whom had suffered their first and only stroke between six months and three years before receiving the injections, remained conscious under light anesthesia throughout the procedure, which involved drilling a small hole through their skulls; the next day they all went home. Although more than three-quarters of them suffered from transient headaches afterward – probably due to the surgical procedure and the physical constraints employed to ensure its precision – there were no side effects attributable to the stem cells themselves, and no life-threatening adverse effects linked to the procedure used to administer them.
The promising results set the stage for an expanded trial of the procedure now getting underway. They also call for new thinking regarding the permanence of brain damage, said Gary Steinberg, MD, PhD, professor and chair of neurosurgery.
‘Clinically meaningful’ results
“This was just a single trial, and a small one,” cautioned Steinberg, who led the 18-patient trial and conducted 12 of the procedures himself. (The rest were performed at the University of Pittsburgh.) “It was designed primarily to test the procedure’s safety. But patients improved by several standard measures, and their improvement was not only statistically significant, but clinically meaningful. Their ability to move around has recovered visibly. That’s unprecedented. At six months out from a stroke, you don’t expect to see any further recovery.”
The trial’s results are detailed in a paper to be published online in Stroke. Steinberg, who has more than 15 years’ worth of experience in work with stem cell therapies for neurological indications, is the paper’s lead and senior author.
Some 800,000 people suffer a stroke each year in the United States alone. About 85 percent of all strokes are ischemic: They occur when a clot forms in a blood vessel supplying blood to part of the brain, with subsequent intensive damage to the affected area. The specific loss of function incurred depends on exactly where within the brain the stroke occurs, and on its magnitude.
Although approved therapies for ischemic stroke exist, to be effective they must be applied within a few hours of the event – a time frame that often is exceeded by the amount of time it takes for a stroke patient to arrive at a treatment center.