PECAM1 and ischemia: In a permanent middle cerebral artery occlusion (pMCAO) model, they found that treatment with an S1P2 specific antagonist reduced BBB leakage after ischemia in mice and prevented depletion of BBB junctional proteins such as VE-cadherin, occludin, claudin-5, and platelet endothelial cell adhesion molecule (PECAM-1).