Researchers in the US may have made a breakthrough that could be good news for stroke sufferers.
Scientists from the Harvard Medical School claim to have found an enzyme that, although harmful to a patient immediately after a stroke, is beneficial during the following days.
The findings, published in Nature Medicine, point to the fact that the matrix metalloproteinase-9 (MMP-9) enzyme may help brain tissue repair itself seven to 14 days after the stroke.
Lead author Eng H Lo commented: "We have mostly thought of MMPs as being 'bad', our data strongly suggest that they play a totally different role during stroke recovery."
Immediately after a stroke, MMPs are believed to mangle brain tissue; heightening the danger of haemorrhage and swelling in the brain.
Many stroke drugs attempt to lessen the impact of MMPs but this new discovery may alter the use of drugs in the recovery process; allowing MMPs to be helpful in the second week after a stroke but still preventing their negative effects immediately after being struck down.