Serum klotho protein levels and their correlations with the progression of type 2 diabetes mellitus

Aim: To investigate the associations of serum alpha-Klotho and beta-Klotho levels with type 2 diabetes mellitus (T2DM) progression. Methods: We evaluated 106 healthy controls and 261 cases of T2DM with or without diabetic complications (range: 45-84 years). Serum alpha-Klotho and beta-Klotho levels were analyzed using enzyme-linked immunosorbent assays. Results: Compared to the healthy controls, alpha-Klotho and beta-Klotho levels were significantly lower among patients with T2DM and with or without diabetic complications (P < 0.05). Furthermore, alpha-Klotho levels were lower in the microalbuminuric and macroalbuminuric groups, compared to the normoalbuminuric group. However, beta-Klotho levels were only lower in the macroalbuminuric group (P < 0.05). Multiple linear regression analyses revealed that ot-Klotho and beta-Klotho levels were positively correlated with the creatinine clearance rate, and negatively correlated with the urinary albumin to creatinine ratio and randomly sampled serum levels of creatinine, blood urea nitrogen, and blood glucose. Moreover, alpha-Klotho and beta-Klotho levels were positively correlated among patients with T2DM (r = 0.693, P < 0.001). Conclusions: Serum levels of alpha-Klotho and beta-Klotho are down-regulated in patients with T2DM. Thus, these proteins may participate in the pathological mechanism of diabetes, and the positive correlation of alpha-Klotho and alpha-Klotho levels indicates that they might have similar mechanisms in T2DM. (C) 2017 Elsevier Inc. All rights reserved.