SELP and myocardial ischemia: Interestingly, Shimomura’s group found that the plasma level of soluble P-selectin peaked significantly at 4 h in patients with acute myocardial infarction after initiation of reperfusion therapy, suggesting that the increase in P-selectin levels may be caused by activation of endothelial cells and platelets after myocardial ischemia or infarction27.