SIRT1 and osteoarthritis: Additionally, recent studies have indicated a potential role for SIRT1 in regulating bone metabolism [23], and reduced levels of SIRT1 in osteoblasts from patients with osteoarthritis, a disorder characterized by inappropriate osteogenesis of bone tissue, lead to increased expression of TGF-β and sclerostin, which regulates bone mineralization via Wnt signaling [24].