The Role of the Chemokines in Myocardial Ischemia and Reperfusion

Chemokines critically regulate basal and inflammatory leukocyte trafficking and may play a role in angiogenesis. This review summarizes our current understanding of the regulation and potential role of the chemokines in myocardial ischemia and reperfusion. Reperfused myocardial infarction is associated with an inflammatory response leading to leukocyte recruitment, healing and scar formation. Neutrophil chemoattractants, such as the CXC chemokine CXCL8 / Interleukin (IL)-8, are upregulated in the infarcted area inducing polymorphonuclear leukocyte infiltration. In addition, mononuclear cell chemoattractants, such as the CC chemokine CCL2 / Monocyte Chemoattractant Protein (MCP)-1, are expressed, leading to monocyte and lymphocyte recruitment in the ischemic area. However, chemokines may have additional effects in healing infarcts beyond their leukotactic properties. We have recently described a marked transient induction of the angiostatic CXC chemokine CXCL10 / Interferon-γ inducible Protein (IP)- 10 in the infarct. Upregulation of angiostatic factors, such as IP- 10, in the first few hours following injury may inhibit premature angiogenesis, until the infarct is debrided and appropriate supportive matrix is formed. Suppression of IP-10 synthesis during the healing phase may allow formation of the wound neovessels, a critical process for infarct healing. Chemokine expression is also noted after a single brief ischemic insult in the absence of myocardial infarction, suggesting a potential role for a chemokine-induced inflammatory response in noninfarctive ischemic cardiomyopathy. Unlike cytokines, which have pleiotropic effects, chemokines have more specific cellular targets. Understanding of their role in myocardial infarction may allow us to design specific therapeutic strategies aiming at optimizing cardiac repair and preventing ventricular remodeling.