Abstract 19634: Deletion of Semaphorin 4d Protects Against Myocardial Ischemia-reperfusion Injury in Mice

Semaphorin 4D (Sema4D) is expressed on the surface of many types of cells including platelets and T-cells. We have previously shown that Sema4D can be shed from the surface of activated platelets by the metalloprotease ADAM17 and that deleting Sema4D in mice inhibits platelet function and reduces lipid deposition in the aorta. Here we asked whether loss of Sema4D expression protects heart in an ischemia/reperfusion model in which the LAD is occluded for 45 min and then reperfused for 1 hour. The results show that there was no difference between Sema4D(-/-) and control (WT) mice with respect to heart size or the area at risk for infarction. However, we found a substantial decrease in infarct size when adjusted for either heart size (10.7% versus 30.2%, p