CDK4 and myocardial infarction: Overexpression of a combination of four cell-cycle regulators including the CDK1-CCNB and CDK4-CCND complexes, effectively promoted cardiomyocytes proliferation and subsequent cell survival following acute or subacute myocardial infarction, both in vitro and in vivo.484 Interestingly, the sustained improvement in cardiac function was observed also four months after treatment.485 CDK1 is potentially involved in the repair mechanisms of infarcted hearts.484 The cyclin D1/CDK4 complex is crucial for triggering cell cycle reentry in numerous cardiomyocytes within the adult heart.