Molecular hydrogen potentiates beneficial anti-infarct effect of hypoxic postconditioning in isolated rat hearts: Novel cardioprotective intervention

Generation of free radicals through incomplete reduction of oxygen during ischemia/ reperfusion is well-described. On the other hand, molecular hydrogen (H2) reduces oxidative stress due to its ability to react with strong oxidants and easily penetrate cells by diffusion, without disturbing metabolic redox reactions. This study was designed to explore cardioprotective potential of hypoxic postconditioning (HpostC) against ischemia/reperfusion (30-min global I/120-min R) in isolated rat hearts using oxygen-free Krebs-Henseleit buffer (KHB). Furthermore, the possibility to potentiate the effect of HpostC by H2 using oxygen-free KHB saturated with H2 (H2+HpostC) was tested. HPostC was induced by 4 cycles of 1-min perfusion with oxygen-free KHB intercepted by 1-min perfusion with normal KHB, at the onset of reperfusion. H2+HPostC was applied in a similar manner using H2 enriched oxygen-free KHB. Cardioprotective effects were evaluated on the basis of infarct size (IS, in % of area at risk, AR) reduction, post-I/R recovery of heart function and occurrence of reperfusion arrhythmias. HPostC significantly reduced IS/AR compared to non-conditioned controls. H2 present in KHB during HPostC further decreased IS/AR compared to the effect of HPostC, attenuated severe arrhythmias, and significantly restored heart function (vs. controls). Cardioprotection by hypoxic postconditioning can be augmented by molecular hydrogen infusion.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Evidence of necroptosis in hearts subjected to various forms of ischemic insults

Long-lasting ischemia can result in cell loss; however, repeated episodes of brief ischemia increase the resistance of the heart against deleterious effects of subsequent prolonged ischemic insult and promote cell survival. Traditionally, it is believed that the supply of blood to the ischemic heart is associated with release of cytokines, activation of inflammatory response and induction of necrotic cell death. In the past few years, this paradigm of passive necrosis as an uncontrolled cell death has been re-examined and the existence of a strictly regulated form of necrotic cell death, necroptosis, has been documented. This controlled cell death modality, resembling all morphological features of necrosis, has been investigated in different types of ischemia-associated heart injuries. The process of necroptosis has been found to be dependent on the activation of RIP1-RIP3-MLKL axis, which induces changes leading to the rupture of cell membrane. This pathway is activated by TNF-Îą, which has also been implicated in the cardioprotective signaling pathway of ischemic preconditioning. Thus, this review is intended to describe the TNF-Îą mediated signaling leading to either cell survival or necroptotic cell death. In addition, some experimental data suggesting a link between heart dysfunction and the cellular loss due to necroptosis are discussed in various conditions of myocardial ischemia.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Non-invasive approach to mend the broken heart: is “remote conditioning” a promising strategy for application in humans?

Currently, there are no satisfactory interventions to protect the heart against the detrimental effects of ischemia-reperfusion injury. Although ischemic preconditioning (PC) is the most powerful form of intrinsic cardioprotection, its application in humans is limited to planned interventions, due to its short duration and technical requirements. However, many organs/tissues are capable of producing â remoteâ PC (RPC) when subjected to brief bouts of ischemia-reperfusion. RPC was first described in the heart where brief ischemia in one territory led to protection in other area. Later on, RPC started to be used in patients with acute myocardial infarction, albeit with ambiguous results. It is hypothesized that the connection between the signal triggered in remote organ and protection induced in the heart can be mediated by humoral and neural pathways as well as via systemic response to short sublethal ischemia. However, although RPC has a potentially important clinical role, our understanding of the mechanistic pathways linking the local stimulus to the remote organ remains incomplete. Nevertheless, RPC appears as a cost-effective and easily performed intervention. Elucidation of protective mechanisms activated in the remote organ may have therapeutic and diagnostic implications in the management of myocardial ischemia and lead to development of pharmacological RPC mimetics.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author