KL and chronic kidney disease: The prominent role of declined SIRT1 expression in the induction of CKD in our study was confirmed by the correlation studies which indicated its negative association with KIM-1, NAG, TGF-β, FGF2, WNT1, β-catenin, TNF-α, and IL-6, and positive association with the antifibrotic markers, α and β klotho and SMAD.