Modulation of programmed forms of cell death by intracoronary levosimendan during regional myocardial ischemia in anesthetized pigs

Powerful mediators of programmed cell death, such as apoptosis and autophagy, can contribute to myocyte cell loss during pathological cardiac conditions. Levosimendan has been shown to exert beneficial hemodynamic effects in presence of global myocardial ischemia and heart failure through vasodilatation and increase of cardiac contractility. Recently, the intracoronary administration of a bolus levosimendan was found to exert favourable cardiac anti-stunning effects without lowering arterial pressure, which limits the use of levosimendan mainly in coronary artery disease. Here we tested whether the intracoronary administration of levosimendan can beneficially modulate programmed cell death in acute regional myocardial ischemia.

Acute regional myocardial ischemia was induced in 20 anaesthetized pigs and intracoronary levosimendan 15 min bolus administration was started 4 h afterwards. The effects of levosimendan on coronary blood flow and cardiac function were evaluated and myocardial biopsies were examined for criteria of autophagy and apoptosis.

The administration of levosimendan caused a significant increase of coronary blood flow (p < 0.05) in absence of changes in cardiac function. Moreover, levosimendan prevented the down-regulation of the anti-apoptotic gene, Bcl-2, and the up-regulation of the apoptotic markers Bax and cytochrome c, which resulted in a reduced expression of TUNEL fragmented nuclei (p < 0.05). Furthermore, levosimendan maintained Beclin 1 at 4 h and potentiated LC3 II expression, these results being consistent with autophagy activation.

Such effects of intracoronary levosimendan bolus administration during regional myocardial ischemia indicate the occurrence of cardio-protection by modulation of programmed form of cell death.