LRP1 and Stroke: Many t-PA-associated BBB breakdown processes during stroke involve t-PA engagement with LRP-1, an interaction which drives upregulation of matrix metalloproteinase (MMP)-3 [13], MMP-9 [26, 27] and vascular endothelial growth factor (VEGF) in brain endothelial cells [28] and microglia [29], activation of the platelet-derived growth factor (PDGF)-CC [12] and Rho-kinase pathways [30] as well as direct cleavage of LRP-1 [31] in astrocytes and control of vascular tone [32] via stimulation of smooth-muscle cells [33].