Figure 5.

The mechanism by which neutrophils repair the vascular endothelium. First, activated neutrophils deposit the antimicrobial peptide cathelicidin, which promotes the adhesion of circulating endothelial progenitor cells through FPR2, at the site of arterial injury. Endothelial progenitor cells recruited in this way can directly cover the injury site but also release angiogenic growth factor in a paracrine manner, thus promoting reendothelialization. Cathelicidin stimulates endothelial progenitor cells to secrete VEGF and EGF, which can promote the repair of damaged endothelial cells. Neutrophils penetrate the vascular endothelium by reacting with endothelial adhesion molecules to reduce blood flow velocity in the vasculature, and then neutrophils cross the vascular wall with the help of a series of adhesion molecules, such as P-, E-, and L-selectin; ICAM-1; and integrins (CD11b, a, and c).