Abstract 357: Antioxidant and Anti-inflammatory Strategies Prevent Endothelial Dysfunction in Chronic Kidney Disease

Abstract

Accelerated atherosclerosis in chronic kidney disease (CKD) is preceded by the development of endothelial dysfunction (ED), with development of a proinflammatory and prothrombotic phenotype and enhanced oxidative stress. The effect of anti-inflammatory and antioxidant strategies on the endothelium has been evaluated in an in vitro model of ED in uremia. Endothelial cells (ECs) were pretreated with the antioxidant enzyme mimetics ebselen, EUK-134 and EUK-118; the flavonoids apigenin, genistein and quercetin, with both antioxidant and anti-inflammatory potential; and two commercially available compounds: N-acetylcysteine (NAC) and defibrotide (DF). There is increasing evidence demonstrating that both NAC and DF exhibit both properties. ECs were exposed to medium containing serum from patients on dialysis (n=10) or from healthy donors (n=15). Changes in the expression of the adhesion receptor ICAM-1 and the production of intracellular reactive oxygen species (ROS) were assessed. Activation of inflammation-related proteins p38 MAPK and NFkappaB (NFκB) were also evaluated. Exposure of ECs to uremic media resulted in a significantly increased expression of ICAM-1, overproduction of ROS and activation of p38MAPK and NFκB compared to control ECs (p<0.05). Ebselen, EUK 134, and EUK118 inhibited ICAM-1 expression and ROS generation in the uremic condition (p<0.01). Regarding flavonoids, only quercetin showed a moderated but significant inhibitory effect on both parameters (p<0.05). NAC and DF exhibited a protective effect on ECs exposed to the uremic insult (p<0.05 for ICAM-1 expression and ROS generation). All the compounds reduced p38MAPK activation (p<0.05). The antioxidant-enzyme mimetics and NAC were able to inhibit the activation of NFκB induced by the uremic media (p<0.05). Endothelial dysfunction associated with CKD is considered to be the first step in the progression of atherosclerosis. Our results indicate that the antioxidant enzyme mimetics, NAC and DF exhibit not only antioxidant but also anti-inflammatory effects on the endothelium. Therefore, further research on the protective effects of these compounds may provide new strategies for the prevention of the cardiovascular complications in uremia.