SIRT1 and osteoarthritis: These findings were consistent with reduced levels of SIRT1 measured in human osteoarthritis (OA) cartilage (Fujita et al., 2011; Takayama et al., 2009), suggesting a potential protective role of SIRT1 in chondrocytes, which was further evidenced by the accelerated development of OA in mice lacking SIRT1 in chondrocyte (Matsuzaki et al., 2014).