Elevated myocardial Akt signaling ameliorates doxorubicin-induced congestive heart failure and promotes heart growth.

Doxorubicin is a chemotherapeutic agent that can induce cardiotoxicity and congestive heart failure (CHF). In this study we tested whether intracoronary Akt1 gene delivery could inhibit doxorubicin-induced CHF. Saline or a replication defective adenoviral vector expressing constitutively-active Akt1 (myrAkt) or beta-galactosidase (betagal) was delivered to the myocardium of 8 week old rats one day prior to initiating doxorubicin administration. In animals receiving saline or betagal, doxorubicin resulted in significant decreases in cardiac function and retarded post-natal heart growth at the 5 weeks time point. In contrast, transduction of myrAkt protected hearts against doxorubicin-induced decreases in fractional shortening and cardiac index, and improved left ventricular function at 5 weeks time point. Delivery of myrAkt also reversed the doxorubicin-induced reduction in post-natal heart growth and diminished lung edema. These data show that myocardial Akt can inhibit doxorubicin-induced reductions in cardiac function and growth, suggesting that manipulation of this signaling pathway may have utility for the treatment of congestive heart failure.