MMP13 and bone inflammation disease: This specific activity of MMP-13, together with its ability to degrade both type I collagen (the primary extracellular matrix component secreted by osteoblasts in the trabecular bone) and type II collagen (the primary fibrillar extracellular matrix component secreted by resting and proliferating chondrocytes in the growth plate) (Inada et al., 2004; Stickens et al., 2004; Tardif et al., 2004) suggests it to be a central agonist of bone resorption and an important target in inflammatory bone diseases.