Blood vessels can be injured by the build-up of atherosclerosis and long-standing hypertension, among other conditions. As a consequence, blood vessels may undergo a process called remodeling, whereby their walls thicken and cause blockages (known as occlusion). In a new study, researchers from the University of Tsukuba discovered how cells marked by platelet-derived growth factor receptor alpha (PDGFRa+) residing predominantly in the most outer layer of blood vessels contribute to their remodeling.