Do immune cells regulate mural cell behaviors in injured arteries?

Current understanding regarding the involvement of immune cells in the maintenance of vascular structures is limited. Recently, it was shown that T cells play crucial roles for normalization of tumor vessels by promoting pericyte coverage. In our previous study, where mice were subjected to wire injury (WI) operations to remove endothelial layers and induce arterial stenosis, we accidentally found that immunodificient mice were resistant to the development of injury-associated stenosis. WI-operated arteries of anti-asialo GM1 monoclonal antibody-treated mice retained intact morphologies: SMCs stayed in tunica media without migrating into tunica intima to form neointima. In SCID mice, tunica media turned into acellular substance as a result of massive escape of SMCs from injured arteries to extravascular spaces. In this review, we discuss possible involvements of immune cells in regulating the behaviors of mural cells in injured arteries.