Stem cell therapy administered shortly after a stroke could significantly increase the sufferer's chance of a complete recovery.
When administered to rats within 30 minutes of suffering a stroke, the rodents made a full recovery within two weeks, a study showed.
The research, published in BioMed Central's open access journal Stem Cell Research & Therapy, found that stem cells from the bone marrow of fat can improve the recovery of rats following a stroke.
Researchers at La Paz University Hospital found that treatment improved the amount of brain and nerve repair, as well as the animal's ability to complete tasks.
Rats were treated intravenously with stem cells half an hour after a stroke. In humans, such rapid response is known to dramatically improve the outcome of victims.
The researchers found improvements in the stem cell group within 24 hours of the treatment, compared to the control group.
The FAST response advertising campaign has aimed to increase awareness of symptoms. Facial and arm weakness and speech problems suggest it is time to call emergency services.
A delay in treatment can result in death or long-term disabilities. A stroke occurs when the blood supply to part of the brain is cut off.
Within two weeks the rats treated with stem cells had near-normal scores in tests, even though the stem cells did not seem to migrate to the damaged area of the brain. They also had higher levels of biomarkers implicated in brain repair.
Stem cells from both bone marrow and fat (adipose) helped treat rats, giving strong implications for human testing. Study author Exuperio Díez-Tejedor, from La Paz University Hospital, said: "Improved recovery was seen regardless of origin of the stem cells, which may increase the usefulness of this treatment in human trials.
"Adipose-derived cells in particular are abundant and easy to collect without invasive surgery."
BBC presenter Andrew Marr recently suffered from a stroke at the age of 53. Fellow presenter Jeremy Vine recently spoke about his recovery, saying: "He's on the mend and he does send a huge thank you to friends and viewers who've bombarded him with goodwill messages.
"He says that's been truly wonderful, he's really looking forward to returning to work in due course and resuming duties on a Sunday morning."