RBP4 and metabolic dysfunction-associated steatotic liver disease: In NAFLD, abnormalities in lipid metabolism, such as increased TG production and excessive uptake of hepatic free fatty acids(FFAs), cause the accumulation of intrahepatic fat (37), which leads to inflammation, the induction of oxidative stress and the production of abnormal lipid molecules affecting signaling pathways, such as leptin, lipocalin and retinol-binding protein-4, eventually leading to IR (38, 39).