CXCL12 and myocardial infarction: Kraemer et al. (2019) for the first time, showed the upregulation and phosphorylation of HSP27 (HSPB1) of human platelets during MI on a cellular level ex vivo, showing a typical intracellular translocation pattern. Therefore, HSP27 (HSPB1) phenotype in platelets was a measurable stress response indicator in MI and other acute ischemic events [38,39]. After MI, the increased expression of CXCL12 was observed in the infarct area and served as a homing signal for endothelial progenitor cells (Jiao et al., 2019).