FGF21 and metabolic dysfunction-associated steatotic liver disease: Although any conclusions regarding the possible association between DR and NAFLD, drawn by both clinical observational studies and experimental studies, remain controversial, a variety of potential molecular mediators have been proposed to associate the eye with the liver, regulating communication and disease progression, such as advanced glycation end products, reactive oxygen species, C-reactive protein, interleukin-6, tumor necrosis factor-a, fibroblast growth factor-21 and hepatocyte growth factor [6].