MMP9 and Stroke: Studies in experimental animal models and stroke patients strongly suggest that MMP-9 plays a central role in tPA-mediated neurotoxicity from thrombolytic therapy for acute stroke (del Zoppo, 1995; Lapchak et al., 2000; Sumii and Lo, 2002; Montaner et al., 2003; Rosell and Lo, 2008).