The osteoprotegerin/RANK/RANKL system: a bone key to vascular disease.

Osteoporosis and atherosclerosis are degenerative disorders of old age that often present together, but recently it has been suggested that the association between osteoporosis and cardio-vascular diseases is not just due to the aging process. The osteoprotegerin (OPG)/receptor activator of nuclear factor-kB (RANK)/RANK ligand (RANKL) system has been identified as a possible mediator of arterial calcification suggesting common links between osteoporosis and vascular diseases. Since the discovery of the OPG/RANK/RANKL system, much has been learned about its role in controlling skeletal biology; however, its role in the context of vascular biology is only beginning to be explored. It has been suggested that OPG might act as an autocrine/paracrine regulator of vascular calcification and might be useful as a serum marker of vascular disease. However, the exact role of OPG (or RANKL/RANK) in vascular calcification is still not completely understood. This review aims to report the recent findings on the relationship between osteoporosis and OPG/RANK/RANKL-mediated vascular disease.