The world's first clinical trial of brain stem cells to treat strokes is set to move to its next phase.
An independent assessment of the first three patients to have had stem cells injected into their brain at Glasgow's Southern General Hospital has concluded it has had no adverse effect, BBC reported.
The assessment paves the way for the therapy to be tested on more patients to find a new treatment for stroke.
The hope is that the stem cells will help to repair damaged brain tissue.
The trial is being led by Prof Keith Muir of Glasgow University. He told BBC News that he was pleased with the results so far.
"We need to be assured of safety before we can progress to trying to test the effects of this therapy. Because this is the first time this type of cell therapy has been used in humans, it's vitally important that we determine that it's safe to proceed - so at the present time we have the clearance to proceed to the next higher dose of cells."
An elderly man was the first person in the world to receive this treatment last year. Since then it has been tried out on two more patients.