Protease-Activated Receptor 2 Deficiency Reduces Cardiac Ischemia/Reperfusion Injury

Objective-To investigate the effect of protease-activated receptor (PAR) 2 deficiency on ischemia/reperfusion (I/R) injury-induced infarct size, inflammation, heart remodeling, and cardiac function. Methods and Results-PAR-2 signaling enhances inflammation in different diseases. The effect of PAR-2 deficiency in cardiac I/R injury is unknown. PAR-2(-/-) mice and wild-type littermates were subjected to 30 minutes of ischemia and up to 4 weeks of reperfusion. Infarct size, oxidative/nitrative stress, phosphorylation of mitogen-activated protein kinases, and inflammatory gene expression were assessed 2 hours after reperfusion. Changes in heart size and function were measured by echocardiography up to 4 weeks after reperfusion. Infarct size was significantly reduced in hearts of PAR-2(-/-) mice compared with wild-type littermates. In addition, oxidative/nitrative stress, phosphorylation of mitogen-activated protein kinase, and expression of proinflammatory genes were significantly attenuated in injured hearts of PAR-2(-/-) mice. Finally, PAR-2(-/-) mice were protected from postinfarction remodeling and showed less impairment in heart function compared with wild-type littermates up to 4 weeks after I/R injury. Conclusion-PAR-2 deficiency reduces myocardial infarction and heart remodeling after I/R injury. (Arterioscler Thromb Vasc Biol. 2010; 30: 2136-2142.)