SIRT1 and osteoarthritis: Sirtuins are a member of class III histone deacetylases (HDACs) which is dependent on NAD+, and seven types of them have been reported in humans.19 Sirt1 has been known as an anti-aging factor and plays an important role in preventing chondrocytes apoptosis and osteoarthritis pathogenesis.20 It has different functions such as regulation of lipid metabolism and adipogenesis.21 Sirt1 interferes with damage-related DNA responses and is associated with increasing age and carcinogenesis.