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.
The assessment paves the way for the therapy to be tested on more patients to find a new treatment for stroke; the hope is the stem cells will help to repair damaged brain tissue, the scientists say.
Prof Keith Muir of Glasgow University, who led the trial, was quoted as saying, "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. The patients have received very low doses of stem cells in trials designed to test the safety of the procedure.
Over the next year, nine more patients will be given progressively higher doses -- again primarily to assess safety -- but doctors will also be using this trial to assess best ways of measuring the effectiveness of the treatment in larger trials, which will begin after 18 months, say the scientists.
The development of stem cell treatments is still at an early stage and it is likely to be many years before these treatments become widely available.
The latest stroke trial is being carried out in collaboration with Reneuron Group plc.
The company`s chief executive officer Michael Hunt said: "The earliest a treatment could be widely available if everything goes very well is five years. It is very much a case of so far, so good. It is still at a very early stage but we draw great comfort from these results."