Indeed, MMP-1 and MMP-2 appear to initiate the damage cascade early during the acute rt-PA thrombolysis phase within 2–6 h (median 3.8 h) after ischemic brain injury, and periods of enhanced BBB permeability are present at 4–8 h and again at 12–16 h after stroke onset. The gene discussed is MMP1; the disease is stroke disorder.