Scientists have helped dogs to walk again after severe spinal injuries - offering hope for paralysed human patients.
Movement was restored to the dogs' hind legs by bridging breaks in the spinal cord using olfactory ensheathing cells (OECs) taken from their noses.
The cells support nerve fibre growth that maintains a communication pathway between the nose and the brain.
One previously crippled dachshund, Jasper, was described by its owner as "whizzing around the house" after undergoing the treatment.
May Hay, from Cambridge, said: "Before the trial, Jasper was unable to walk at all. When we took him out we used a sling for his back legs so that he could exercise the front ones. It was heartbreaking."
The random controlled trial is the first to demonstrate effective spinal cord repair in "real life" injury cases.
Professor Robin Franklin, one of the study leaders from Cambridge University , said: "Our findings are extremely exciting because they show for the first time that transplanting these types of cell into a severely damaged spinal cord can bring about significant improvement."
In the trial, scientists studied 34 pet dogs that had all suffered spinal cord injuries as a result of accidents and back problems. None was injured deliberately for the sake of research.
One group of dogs had the OEC cells taken from the lining of their own noses and injected into the injury site. Another was only injected with the liquid in which the cells were suspended.
Dogs were tested for neurological function at one-month intervals and had their walking ability assessed on a treadmill.
Those that had been injected with the OEC cells showed improved movement.
Prof Franklin said the technique could restore "at least a small amount" of movement in humans with spinal cord injuries, but warned patients not to expect too much from the approach.
He said the procedure was likely to be used as part of a combination of treatments, alongside drug and physical therapies.
Professor Geoffrey Raisman, chair of neural regeneration at University College London, said: "This is not a cure for spinal cord injury in humans - that could still be a long way off.
"But this is the most encouraging advance for some years and is a significant step on the road towards it."