SIRT1 and metabolic dysfunction-associated steatotic liver disease: In NAFLD patients, SIRT1, SIRT2, SIRT3, SIRT5, and SIRT6 are dramatically down-regulated in livers (Wu et al., 2014; Ren et al., 2021), and plasma levels of SIRTs is highly associated with NAFLD (Mariani et al., 2015).