A small study of stem cell transplants into the brain has demonstrated striking benefits in stroke patients when administered long after the stroke itself, past the point at which any further natural recovery is expected:
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. 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.
"This was just a single trial, and a small one. 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." 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. Consequently, only a small fraction of patients benefit from treatment during the stroke's acute phase. The great majority of survivors end up with enduring disabilities. Some lost functionality often returns, but it's typically limited.
For the trial, the investigators screened 379 patients and selected 18, whose average age was 61. Into these patients' brains the neurosurgeons injected so-called SB623 cells - mesenchymal stem cells derived from the bone marrow of two donors and then modified to beneficially alter the cells' ability to restore neurologic function. Afterward, patients were monitored via blood tests, clinical evaluations and brain imaging. Interestingly, the implanted stem cells themselves do not appear to survive very long in the brain. Preclinical studies have shown that these cells begin to disappear about one month after the procedure and are gone by two months. Yet, patients showed significant recovery by a number of measures within a month's time, and they continued improving for several months afterward, sustaining these improvements at six and 12 months after surgery. Substantial improvements were seen in patients' scores on several widely accepted metrics of stroke recovery. Perhaps most notably, there was an overall 11.4-point improvement on the motor-function component of the Fugl-Meyer test, which specifically gauges patients' movement deficits. "This wasn't just, 'They couldn't move their thumb, and now they can.' Patients who were in wheelchairs are walking now."