Alpha lipoic acid protects the heart against myocardial post ischemia-reperfusion arrhythmias via KATP channel activation in isolated rat hearts

The cardiovascular effects of alpha lipoic acid were evaluated in isolated rat hearts exposed to ischemia-reperfusion injury in vitro. Alpha-lipoic acid raised the level of sulfane sulfur playing an important role in the release of hydrogen sulfide. H2S was shown to prevent the post-reperfusion arrhythmias and to protect the cardiomyocytes from death caused by hypoxia. The activation of potassium ATP-sensitive channels (KATP channels) is one of the most important mechanisms of action of hydrogen sulfide in the cardiovascular system. The aim of this study was to investigate whether alpha lipoic acid can prevent the occurrence of post-reperfusion arrhythmias in vitro using a Langendorff model of ischemia-reperfusion in rats affecting the KATP channels. Alpha lipoic acid significantly improved post-reperfusion cardiac function (reducing incidence of arrhythmias), especially in a dose of 10−7 M. These cardiovascular effects of this compound on the measured parameters were reversed by glibenclamide, a selective KATP blocker. Alpha lipoic acid increased the level of sulfane sulfur in the hearts. This may suggest that the positive effects caused by alpha lipoic acid in the cardiovascular system are not only related to its strong antioxidant activity, and the influence on the activity of such enzymes as aldehyde dehydrogenase 2, as previously suggested, but this compound can affect KATP channels. It is possible that this indirect effect of alpha lipoic acid is connected with changes in the release of sulfane sulfur and hydrogen sulfide.