Circulating cellular players in vascular calcification.

Vascular calcification is the deposition of calcium-phosphate salts in the form of hydroxyapatite within the arterial wall. This is a finely regulated process to such an extent that it shares some mechanisms with endochondral and membranous embryonic ossification. Current theories describe vascular calcification as the imbalance between mechanisms, which promote calcification and those that inhibit it. Canonical cellular players in this scenario include endothelial cells, resident vascular smooth muscle cells and immune cells. Nevertheless, the last decade has seen the rise of extraparietal cells as important players in vascular biology and also in the setting of ectopic calcification. After an overview of the mechanism involved in vascular calcification, we herein discuss the potential role of different populations of circulating calcifying cells.