Thus, the aim of this study was to investigate: (a) The Klotho levels (soluble and transmembrane protein in kidney) and its relationship to fibrosis; and (b) If Wnt/β-catenin and AGE/RAGE pathways are involved in heart and kidney fibrosis in a long-term (24 weeks) rat model that resembles the T1DM. Here, KL is linked to type 1 diabetes mellitus.