MMP9 and Stroke: Even though MMPs are involved in cell remodeling and dynamical homeostasis during development, aberrant regulation and activity of MMPs, particularly the gelatinase (MMP-9/2), have also been shown in pathological conditions, including angiogenesis in cancer, disruption of the blood—brain barrier, as well as neuroinflammation in stroke and traumatic brain injury (TBI) [1–7].