Fenofibrate protects endothelial cells against the harmful effects of TNF-alpha

Abstract

Introduction: Fenofi brate exerts pleiotropic effects on endothelial cells (ECs) by, amongst others, increasing nitric oxide (NO) production. We aimed to investigate fenofi brate’s putative benefi cial actions in healthy or TNF-alpha-induced dysfunctional ECs. Methods: Fenofi brate-induced pro-vasodilatory re- sponses were assessed in aortic rings (50 - 125µM; 30min) with and without L-NMMA (100µM). Rat cardiac microvascular ECs were treated with fenofi brate (30 and 50µM; 1h). In the pre-treatment experiments, feno- fi brate (50µM) was administered one hour before TNF- alpha treatment (20ng/ml; 24h). NO-production (DAF- 2/DA or Griess assay), mitochondrial ROS-production (MitoSox™), cell viability (propidium iodide staining), and changes in the expression/phosphorylation of critical endothelial proteins were measured by Western blotting. Results: Fenofi brate increased NO-production ˜2-fold in healthy ECs (p<0.05 vs. vehicle). A ˜23% pro-vasodilatory response was induced in aortic rings, which was reversed by L-NMMA (p<0.05 vs. fenofi brate). Fenofi brate pre- treatment ameliorated TNF-alpha-induced endothelial dysfunction by reversing the loss of NO, improving oxidative stress, restoring cell viability and preventing caspase-3 activation. Protective effects were under- pinned by ˜47% and ˜49% up-regulation of activated eNOS and AMP-kinase, respectively (p<0.05 vs. TNF- alpha). Conclusions: Fenofi brate protects TNF-alpha-induced dysfunctional ECs via up-regulated eNOS-NO, reduced oxidative stress and improved cell viability. These novel fi ndings warrant further investigations to explore the potential use of fenofi brate as an anti-endothelial dys- function therapeutic agent. SAHeart 2017;14:22-34 Ca