S100A9, as a potent activator of the innate immune response, as well as the damage-associated molecular pattern (DAMP) protein, is abundantly expressed in neutrophils and rapidly released from activated neutrophils, monocytes/macrophages, and dying cardiomyocytes into the coronary and systemic circulation after myocardial ischemia (Schiopu and Cotoi, 2013). Here, S100A9 is linked to myocardial ischemia.