Antioxidant and Anti-Inflammatory Strategies Based on the Potentiation of Glutathione Peroxidase Activity Prevent Endothelial Dysfunction in Chronic Kidney Disease

Abstract

BACKGROUND/AIMS: Accelerated atherosclerosis in chronic kidney disease (CKD) is preceded by endothelial dysfunction (ED), which exhibits a proinflammatory and prothrombotic phenotype and enhanced oxidative stress. In this study, the effect of several compounds with anti-inflammatory and/or antioxidant properties on uremia-induced endothelial dysfunction has been evaluated in an in vitro model. METHODS: Endothelial cells (ECs) were exposed to sera from uremic patients in the absence and presence of the flavonoids apigenin, genistein and quercetin, the antioxidant enzyme mimetics (AEM) ebselen (glutathione peroxidase mimetic), EUK-134 and EUK-118 (both superoxide dismutase mimetics), and the pharmacological drug N-acetylcysteine (NAC). We explored changes in the expression of adhesion receptors on the cell surface, by immunofluorescence, the production of radical oxygen species (ROS), by fluorescence detection, and the activation of signaling proteins related to inflammation, by both a phosphospecific antibody cell-based ELISA and immunoblotting techniques. RESULTS: Uremic media induced a significantly increased expression of ICAM-1, overproduction of radical oxygen species (ROS) and activation of p38 mitogen activated protein kinase (p38MAPK) and Nuclear Factor kB (NFkB) in ECs. Quercetin, the AEM and NAC showed a significant inhibitory effect on both ICAM-1 expression and ROS generation (p<0.05). All the compounds reduced p38MAPK activation, but only the AEM, especially ebselen, and NAC, both potentiating the glutathione peroxidase pathway, also inhibited NFkB activation. These two compounds were capable of increasing endothelial glutathione levels, especially in response to uremia. CONCLUSION: Our results indicate that the potentiation of the antioxidant pathways can be an effective strategy to improve endothelial dysfunction in uremia and a potential target to reduce the cardiovascular risk in this population.