PECAM1 and chronic obstructive pulmonary disease: It has been shown to mediate endothelial regeneration in an animal model of chronic obstructive pulmonary disease (COPD) by enhancing the mobilization and migration of endothelial progenitor cells (EPCs, CD45−CD34+CD31+), CD309+-endothelial cells, and angiogenesis precursors (CD45−CD117+CD309+) to the lung (Skurikhin et al., 2021).