Silverman et al. also showed the accumulation of endothelial progenitor cell in synovium in RA using the CIA mouse model, which suggests that the interaction of VCAM-1 with α4β1 integrin mediates the recruitment of endothelial progenitor cells to promote neovascularization in RA synovial cells [59]. Here, VCAM1 is linked to rheumatoid arthritis.