Endocrine Abstracts

Introduction: Accumulating evidence suggests that one of the most significant contributors to endothelial dysfunction is increased oxidative stress. Excessive reactive oxygen species (ROS) generation can have injurious effects within the vasculature including elevated expression of adhesion molecules, stimulation of vascular smooth muscle cell proliferation, and promotion of endothelial cell apoptosis; events which culminate in the formation and progression of atherosclerotic plaque. Tumour necrosis factor related apoptosis inducing ligand (TRAIL), a member of the tumour necrosis factor (TNF) superfamily, has been shown to exhibit anti-atherosclerotic properties in animal studies. Preliminary studies from our own group, indicate that under pro-atherogenic oscillatory flow, TRAIL treatment of human aortic endothelial cells (HAECs) can shift net gene expression toward an ‘atheroprotected’ phenotype by up-regulating anti-oxidant genes. The aim of this study therefore was to confirm the anti-oxidant potential of TRAIL at a functional level, by investigating the effect of TRAIL on TNF-α and hyperglycaemia induced ROS production.

Methods: Primary human-derived HAECs were cultured in six-well plates and exposed to pro-oxidant conditions (TNF-α 100 ng/ml or Glucose 30 mmol, 24 h), in the presence and absence of Recombinant TRAIL (100 ng/ml, 24 h). Flow cytometry using dihydroethidium staining was utilised to measure ROS.

Results: TNF-α and hyperglycaemia significantly increased ROS production from HAECs, whilst TRAIL alone had no effect on ROS production. When co-cultured with TNF-α however, TRAIL significantly attenuated TNF-α induced ROS release (n=3, P<0.05). TRAIL also significantly attenuated hyperglycaemia induced ROS release (n=3, P<0.05).

Conclusion: TRAIL may impart protective effects on the vascular endothelium, in-part through reduction of oxidative stress. Though the anti-oxidant mechanism is unclear, this effect does not appear to be mediated by TNF-α antagonism.