Osteoprotegerin (OPG), also known as OCIF or TNFRSF11B, is a cytokine receptor, and a member of the tumor necrosis factor (TNF) receptor superfamily. OPG can reduce the production of osteoclasts by inhibiting the differentiation of osteoclast precursors into osteoclasts and also regulates the resorption of osteoclasts in vitro and in vivo. Recombinant human OPG specifically acts on bone, increasing bone mineral density and bone volume.
Elevated OPG levels has been reported in heart diseases, in placebo effect serum responses in IBS patients and in severe mental disorders. In recent years, it has been hypothesized that OPG may be a link between bone and cardiovascular disease. It has been particularly related to the increase in cardiovascular risk in patients suffering from diabetes.