Figure 1.

A brief illustration of MSCs and VC and alternation of the microenvironment. In the damaged vessel under the calcification process, SDF-1, PDGF, and TGF-β are released to recruit MSCs from bone marrow and circulation. (a) In this microenvironment, damage of the vessel wall is slight and the effect of oxidative stress and inflammation is very minimal. In addition, fewer VSMCs have been induced to osteoblasts. MSCs are viable and inhibit VSMC osteogenesis differentiation by a paracrine mechanism. (b) In this microenvironment, the vessel is damaged a lot by heavy oxidative stress and inflammation. Several phenotypic transformations of VSMCs have taken place. MSCs tend to undergo apoptosis and differentiate into osteoblast-like cells, which facilitate the VC progress.