PTGER4 and myocardial infarction: Despite the fact that there is still no direct evidence showing the role of Stat3 signaling in EP4-mediated cardioprotection, the in vivo model, cardiac-specific EP4 knockout mice with myocardial infarction, exhibited decreased hypertrophic changes but worsened cardiac function, suggesting that activation of EP4 signaling may contribute to the compensatory survival of cardiomyocytes for maintaining the normal cardiac function.