SOST and osteoarthritis: Sclerostin, with osteoblasts and osteocytes, is overexpressed also in chondrocytes of focal cartilage lesions of surgically generated osteoarthritis, exhibiting complex effects: inhibition of aggrecanolysis, increased expression of structural components, such as collagen type II and aggrecan, downregulation of catabolic enzymes and their inhibitors, MMP, distintegrin, ADAMTs, and tissue inhibitors of metalloproteinases (Figure 2) [135].