People who received the world’s first stem cell treatment for strokes have shown measurable reductions in disability and handicap a year after the injection into their damaged brains.

Some can move limbs and manage everyday tasks that were impossible before they received an injection of neural progenitor stem cells, which were clones of cells originally taken from the cortex of a donated fetus.

Apart from physical rehabilitation, there are few treatments for people left severely disabled by a stroke. Demand for more options is high, with 800,000 new cases each year in the US and 150,000 in the UK.

“We’re encouraged, and it’s a nice progressive piece of news,” says Michael Hunt, the chief executive officer of ReNeuron, the company in Guildford, UK, that developed the treatment. “We must be circumspect, but we are seeing what seems to be a general trend towards improvement in a disparate group of patients,” he says.


ReNeuron presented its latest results on the first 11 patients on 7 May in Nice, France, at the 23rd European Stroke Conference. They build on interim findings released last year.

Off the plateau

The patients in the PISCES trial (Pilot Investigation of Stem Cells in Stroke) had all suffered their strokes at least six months before treatment and were all chosen because their symptoms had plateaued, making any improvements more likely to be the result of treatment.

There were improvements in median scores on all five scales used to measure the patients’ recovery.

On a score that measures quality of life from 0 to 100, patients began with a median score of 45, but within a year this had risen by 18 points, a 40 per cent improvement.

Rankin Scores, which grade disability and handicap from healthy (0) to dead (6) improved from a median of 3 at the start to 2 for four of the patients, although the rest remained the same. “That’s equivalent to taking a patient down a whole level of dependency, and equates to a 20 per cent improvement,” says Hunt. Scores on all the other three scales were higher at 12 than at three months, suggesting the improvements were continuing.

The company is now actively recruiting for a second, larger trial in 41 people. They will be recruited sooner after their strokes – within two to three months – in the hope that earlier treatment will prevent some of the irreversible scarring. It will also deploy a harder but more objective measure of improvement in which patients have to try lifting a wooden block onto a platform. Hunt expects full results by the end of 2015.

“While this research is still at a very early stage, it shows that stem cell therapy could be a safe and effective treatment for stroke patients living with disability,” said Madina Kara, a neuroscientist at the UK Stroke Association. “We’re looking forward to the results of the larger trial, which could help improve our understanding of the potential benefits of stem cell therapy.”

ReNeuron’s supporting experiments in animals suggest that the cells ease symptoms by reducing brain inflammation and releasing growth factors that help brain cells recolonise damaged areas.