Matrix Gla protein: the inhibitor of vascular and osteoarticular calcifications

Ectopic vascular calcification is a cardiovascular risk factor. This phenomenon is no longer regarded as a simple precipitation of calcium phosphate in the extracellular matrix, but it is considered to be the result of an active process similar to bone mineralization. Also, calcium is deposited at osteoarticular level as calcium phosphate or hydroxy-apatite crystals, initially leading to the formation of articular and periarticular asymptomatic deposits. Ectopic calcification inhibitors play a central role in the association of vascular calcification with reduced bone mineral density, a phenomenon called “calcification paradox”. Matrix Gla-protein (MGP) is a local inhibitor of ectopic calcifications. This paper reviews up-to-date information about the fundamental aspects, the determination methods and the clinical implications of MGP in vascular and osteoarticular pathology.