According to the World Health Organisation (WHO), 80 percent of the 15 million strokes that occur each year are caused by the type of blood clots in the brain that tPA can dissolve. Today, less than 3% of patients with this type of stroke receive tPA because the narrow safety window has often passed by the time a stroke patient reaches a hospital and is diagnosed. If the planned clinical trial with stroke patients in Sweden confirms the findings of the present study, there is great promise that imatinib or similar drugs could be administered to stoke patients to increase the therapeutic window of tPA.
The basis for this novel proposal is the key growth factor PDGF-CC, which has now been discovered to control the blood brain barrier (a structure that normally shields the brain from the blood). When tPA acts on PDGF-CC, the blood-brain barrier becomes porous and can start to leak. Imatinib inhibits the detrimental effect of PDGF-CC by binding to its receptor PDGFR alpha, seemingly without hindering tPA's therapeutic effect, which is to break down clots that have lodged in the brain's blood vessels.
"Ten years ago our research group identified the growth factor PDGF-CC, and we are now very excited having unravelled a mechanism in the brain involving this factor", says Professor Ulf Eriksson, who leads the LICR team. "This finding has indeed the potential to revolutionise the treatment of stroke."