Stroke patients have recovered faster after being injected with stem cells taken from their own bone marrow, scientists say.
Twenty-five survivors had their marrow cells infused back into their blood and saw their recovery boosted by one point on a six-point scale.
Researchers at the University of Texas in Houston now hope to move forward with broader tests of the experimental therapy.
The stem cells, which are essentially blank building blocks for the body to heal itself with, appear to have helped nerves regrow in the brain.
The trial comes after former Formula One champion Michael Schumacher was last week believed to have had stem cell treatment to help his brain recover from a coma he entered after a skiing accident in 2013.
The stroke therapy works by bone marrow cells being taken from the patient's own skeleton and then infused back into their blood, when they can travel to the brain to help it heal (stock image)
The 25 patients were all given injections of their own bone marrow cells within 72 hours of turning up at a hospital with stroke symptoms.
Their recovery progress was compared to 185 patients who didn't have the infusions and was found to be moving faster.
Neurology professor Dr Sean Savitz said: 'In the typical stroke injury, you can see the degeneration of the nerve tracts where it thins out.
'What surprised us was that after three to six months, we could see the tracts thicken up again in some patients.
'We do not typically see that same level of response in patients with such severe strokes.
'But further research will be needed to determine if the return of the nerve tracts is because of the cell treatment or part of natural recovery.'
More than 100,000 strokes happen every year in the UK and there are around 1.2million stroke survivors alive today, but it's still a leading cause of death.
People who live in noisy urban areas are more likely to have a stroke than those close to green space, according to research.
A study of 2,761 patients in Spain found the risk of stroke rose by almost a third among people in areas with the most traffic noise.
The research couldn't explain whether the danger came from the noise itself or whether the noise was simply a sign of living in a more polluted, less healthy area.
But the scientists suggested people living in noisy areas may be more likely to be stressed out or have high blood pressure, or be less likely to exercise.
Green space around the home also played a part in people's risk of stroke.
Living with at least 984 feet (300m) of green space around the street led to a 25 per cent lower chance of suffering a severe stroke than not doing so.
The risks were relative, meaning someone in a noisy area didn't have a one-in-three chance of having a stroke, just a 30 per cent higher risk than someone in a quiet area (for example, a rise from one in 10,000 risk to 1.3 in 10,000).
The research was published in the journal Environmental Research.
In the US, about 795,000 people have strokes annually and some 140,000 of them die – about one out of every 20 deaths.
Stroke damages the brain by starving its nerve cells of oxygen when the blood flow to the organ is stopped.
As these nerve cells suffocate and die off, parts of the brain shut down, leaving people in some cases unable to move their limbs properly, remember things or speak.
To recover from stroke the patients' nerves must regrow, which can be a long and sometimes impossible process.
Stem cells, which Dr Savitz's team used from the patients themselves, may be able to boost this recovery by essentially providing