Osteopontin (OPN) is a multifunctional molecule highly expressed in chronic
inflammatory and autoimmune diseases, and it is specifically localized in and around
inflammatory cells. OPN is a secreted adhesive molecule, and it is thought to aid in the recruitment of monocytes-macrophages and to regulate cytokine production in macrophages, dendritic cells, and T-cells. OPN has been classified as T-helper 1 cytokine and thus believed to exacerbate
inflammation in several chronic
inflammatory diseases, including atherosclerosis. Besides
proinflammatory functions, physiologically OPN is a potent inhibitor of mineralization, it prevents ectopic calcium deposits and is a potent inducible inhibitor of vascular calcification. Clinically, OPN plasma levels have been found associated with various
inflammatory diseases, including cardiovascular burden. It is thus imperative to dissect the OPN
proinflammatory and anticalcific functions.