Exogenous carbon monoxide does not affect cell membrane energy availability assessed by sarcolemmal calcium fluxes during myocardial ischaemia-reperfusion in the pig

The role of gasotransmitters NO, H2S and CO in myocardial ischaemia/reperfusion injury and cardioprotection by preconditioning, postconditioning and remote conditioning

Ischaemic heart disease is one of the leading causes of morbidity and mortality worldwide. The development of cardioprotective therapeutic agents remains a partly unmet need and a challenge for both medicine and industry, with significant financial and social implications. Protection of the myocardium can be achieved by mechanical vascular occlusions such as preconditioning (PC), when brief episodes of ischaemia/reperfusion (I/R) are experienced prior to ischaemia; postconditioning (PostC), when the brief episodes are experienced at the immediate onset of reperfusion; and remote conditioning (RC), when the brief episodes are experienced in another vascular territory. The elucidation of the signalling pathways, which underlie the protective effects of PC, PostC and RC, would be expected to reveal novel molecular targets for cardioprotection that could be modulated by pharmacological agents to prevent reperfusion injury. Gasotransmitters including NO, hydrogen sulphide (H2S) and carbon monoxide (CO) are a growing family of regulatory molecules that affect physiological and pathological functions. NO, H2S and CO share several common properties; they are beneficial at low concentrations but hazardous in higher amounts; they relax smooth muscle cells, inhibit apoptosis and exert anti-inflammatory effects. In the cardiovascular system, NO, H2S and CO induce vasorelaxation and promote cardioprotection. In this review article, we summarize current knowledge on the role of the gasotransmitters NO, H2S and CO in myocardial I/R injury and cardioprotection provided by conditioning strategies and highlight future perspectives in cardioprotection by NO, H2S, CO, as well as their donor molecules.

Use of carbon monoxide in minimizing ischemia/reperfusion injury in transplantation

Although carbon monoxide (CO) is known to be toxic because of its ability to interfere with oxygen delivery at high concentrations, mammalian cells endogenously generate CO primarily via the catalysis of heme by heme oxygenases. Recent findings have indicated that heme oxygenases and generation of CO serve as a key mechanism to maintain the integrity of the physiological function of organs and supported the development of a new paradigm that CO, at low concentrations, functions as a signaling molecule in the body and exerts significant cytoprotection. Consequently, exogenously delivered CO has been shown to mediate potent protection in various injury models through its anti-inflammatory, vasodilating, and antiapoptotic functions. Ischemia/reperfusion (I/R) injury associated with organ transplantation is one of the major deleterious factors limiting the success of transplantation. Ischemia/reperfusion injury is a complex cascade of interconnected events involving cell damage, apoptosis, vigorous inflammatory responses, microcirculation disturbance, and thrombogenesis. Carbon monoxide has a great potential in minimizing I/R injury. This review will provide an overview of the basic physiology of CO, preclinical studies examining efficacy of CO in I/R injury models, and possible protective mechanisms. Carbon monoxide could be developed to be a valuable therapeutic molecule in minimizing I/R injury in transplantation.