KL and chronic kidney disease: In CKD patients on dialysis, the study observed increased AGT expression, elevated transforming growth factor-beta 1 (TGF-β1), heightened connective tissue growth factor (CTGF), and the accumulation of fibrillar collagens 1 and 3 in the myocardial tissue, all associated with elevated cardiac FGF23 levels and Klotho deficiency.