Reduction of oxidative stress in chronic kidney disease does not increase circulating α-klotho concentrations

Abstract

The CKD-associated decline in soluble α-Klotho levels is considered detrimental. Some in vitro and in vivo animal studies have shown that anti-oxidant therapy can upregulate the expression of α-Klotho in the kidney. We examined the effect of anti-oxidant therapy on α-Klotho concentrations in a clinical cohort with mild tot moderate chronic kidney disease (CKD). We performed a post-hoc analysis of a prospective randomized trial involving 62 patients with mild to moderate CKD (the ATIC study), all using an angiotensin-converting enzyme inhibitor (ACEi) or angiotensin receptor blocker (ARB) for 12 months. On top of that, the intervention group received anti-oxidative therapy consisting of the combination of pravastatin (40 mg/d) and vitamin E (α-tocopherol acetate, 300 mg/d) while the placebo was not treated with anti-oxidants. α-Klotho concentrations were measured at baseline and after 12 months of anti-oxidant therapy. Data were analysed using T-tests and Generalized Estimating Equations, adjusting for potential confounders such as vitamin D, parathyroid hormone, fibroblast-growth-factor 23 (FGF23) and eGFR. The cohort existed of 62 patients with an eGFR (MDRD) of 35 ± 14 ml/min/1.72m2, 34 were male and mean age was 53.0 ± 12.5 years old. Anti-oxidative therapy did successfully reduce oxLDL and LDL concentrations (P <0.001). α-Klotho concentrations did not change in patients receiving either anti-oxidative therapy (476.9 ± 124.3 to 492.7 ± 126.3 pg/mL, P = 0.23) nor in those receiving placebo 483.2 ± 142.5 to 489.6 ± 120.3 pg/mL, P = 0.62). Changes in α-Klotho concentrations were not different between both groups (p = 0.62). No evidence was found that anti-oxidative therapy affected α-Klotho concentrations in patients with mild-moderate CKD.