Thiazolidinediones (TZDs) are agonists of peroxisome proliferator-activated receptor γ (PPAR-γ) and have been reported to induce klotho gene expression in a time- and dose-dependent manner in various renal epithelial cells, which may contribute to improving the symptoms and pathology of DN (149–151). This evidence concerns the gene KL and liver dysplastic nodule.