Stromal derived factor 1α: A chemokine that delivers a two-pronged defence of the myocardium

Alleviating myocardial injury associated with ST elevation myocardial infarction is central to improving the global burden of coronary heart disease. The chemokine stromal cell-derived factor 1 alpha (SDF-1 alpha.) has dual potential benefit in this regard. Firstly, SDF-1 alpha is up-regulated in experimental and clinical studies of acute myocardial infarction (AMI) and regulates stem cell migration to sites of injury. SDF-1 alpha delivery to the myocardium after AMI is associated with improved stem cell homing, angiogenesis, and left ventricular function in animal models, and improvements in heart failure and quality of life in humans. Secondly, SDF-1 alpha may have a role in remote ischaemic conditioning (RIC), the phenomenon whereby non-lethal ischaemia-reperfusion applied to an organ or tissue remote from the heart protects the myocardium from lethal ischaemia-reperfusion injury (IRI). SDF-1 alpha is increased in the serum of rats subjected to RIC and protects against myocardial IRI in ex vivo studies. Despite these potential pleiotropic effects, a limitation of SDF-1 alpha is its short plasma half-life due to cleavage by dipeptidyl peptidase-4 (DPP-4). However, DPP-4 inhibitors increase the half-life of SDF-1 alpha by preventing its degradation and are also protective against lethal IRI. In summary, SDF-1 potentially delivers a 'two-pronged' defence of the myocardium: acutely protecting it from IRI while simultaneously stimulating repair by recruiting stem cells to the site of injury. In this article we examine the evidence for acute and chronic cardioprotective roles of SDF-1 alpha and discuss potential therapeutic manipulations of this mechanism with DPP-4 inhibitors to protect against lethal tissue injury in the clinical setting. (C) 2014 Elsevier Inc. All rights reserved.