Conversely, NAD+ repletion displays a protective effect against NAFLD, probably mediated by the induction of mitochondrial unfolded protein response (UPRmt), an adaptive mechanism dependent on the histone deacetylases SIRT1 and SIRT3, aimed to enhance mitochondrial activity and hepatic β-oxidation [126]. This evidence concerns the gene SIRT1 and metabolic dysfunction-associated steatotic liver disease.