SIRT1 and metabolic dysfunction-associated steatotic liver disease: We recently elucidated a novel lipophagic mechanism by which metformin, a kind of anti-diabetic drug that disturbs mitochondrial complex I of the electron transport chain, alleviates non-alcoholic fatty liver disease (NAFLD) by inducing the sirtuin class of histone/protein deacetylases sirtuin 1 (SIRT1)-mediated autophagy independent of 5′ adenosine monophosphate-activated protein kinase (AMP-activated protein kinase) [1].