In conclusion, a number of experimental studies suggest that neutrophils are in fact the main cellular course of MMP-9 following stroke (not resident brain cells) and that these cells use MMP-9 to transmigrate into ischemic tissue, contribute to ischemic injury in the form of ECM degradation, BBB permeability changes, vasogenic edema, and HT, whilst also stimulating the release of MMP-9 from resident brain cells such as neurons and microglia. Here, MMP9 is linked to stroke disorder.