Figure 1.

Overview of bone vasculature and perivascular cells (PVCs). Distinct PVC populations are found associated with particular vessel types within the bone. Arteries are associated with smooth muscle cells (SMCs) that express α-smooth muscle actin (αSMA) and NG2. Arterioles, which connect arteries to the type H vasculature of the metaphysis, have associated PVCs that express platelet-derived growth factor receptor (PDGFR)β, nestin, and NG2. The type H vessels of the metaphysis are associated with PVCs that express PDGFRβ and NG2. In this region, mesenchymal stem and progenitor cells (MSPCs) expressing nestin and Sca1 are also present. Type L sinusoids of the diaphysis associate with PVCs expressing PDGFRα and leptin receptor (LEPR) as well as CXCL12-abundant reticular (CAR) cells.