Abstract 310: Inhibition of Class I Histone Deacetylase Activity Improves Left Ventricular Contractile Function and Cardiac Strain in Coronary Artery Occlusion-Induced Myocardial Infarction

Protection from coronary heart disease-induced damage of the myocardium during myocardial infarction (MI) injury has been a target of investigation for the development of innovative cardioprotective therapies. Histone deacetylases (HDACs) are a class of enzymes that affect the transcriptional regulation of genes during pathological conditions. We observed that class I/IIb HDAC activity was nearly 5 times greater in the 7-day post-MI LV when compared to the sham ventricles. In vitro inhibition studies indicated that the majority of increased activity was due to class I HDACs. Therefore we hypothesized that suppression of class I HDACs would prevent the pathophysiological changes occurring during MI, thus improving LV pump function in post-MI myocardium. CD-1 mice were administered with the a class I HDAC inhibitor pimelic diphenylamide (PD106) or vehicle immediately after induction of MI and the treatment continued every other day for 7 days post MI. LV end-diastolic volumes, expressed as change from pre-MI values, was significantly lower in the PD106 treated mice compared to vehicle treated mice. Further, the post-MI reduction in LV ejection faction was significantly attenuated in the PD106-treated mice compared to the MI alone group. Similarly, echo cardiac strain analysis showed improved LV strain and better coherence in contractile function among infarct and border zones in PD106 MI group compared to MI only. These unique findings demonstrate that class I HDAC inhibitors may provide a novel therapeutic means to attenuate adverse post-MI LV remodeling.