A cartilage-derived inhibitor of neovascularization and metalloproteinases.

It is now recognized that persistent neovascularization is a characteristic feature of a number of serious diseases including rheumatoid arthritis. In this case, deregulated capillary growth is a prominent event in the development of the rheumatoid synovial pannus. Cartilage is a normally avascular tissue and it has been suggested that a decrease or depletion of inhibitors of angiogenesis might be responsible, at least in part, for the vulnerability of cartilage to synovial attack. Our laboratory has recently purified and characterized a potent inhibitor of angiogenesis in vivo and in vitro from cartilage and from the conditioned media of chondrocytes. Importantly, this protein is also an inhibitor of mammalian collagenase.