O46 Selenium supplementation and modified high-intensity interval training (m-HIIT) to modulate systemic oxidative stress in sedentary overweight/obese adults: In vitro and in vivo studies

Abstract

Obesity is characterised by systemic oxidative stress (OS) resulting from high levels of reactive oxidative species (ROS) and reduced antioxidant capacity. OS plays a fundamental role in cardiovascular disease (CVD) development by initiating atherosclerotic plaque formation. Increased dietary antioxidants’ intake or up-regulation of endogenous antioxidant enzymes may counteract OS and lower CVD risk. Essential micronutrient selenium supplementation and regular physical activity increase endogenous antioxidant enzyme Glutathione Peroxidases (GPx) activity. However, it is unknown whether modified high-intensity interval training (m-HIIT), an emerging time-efficient exercise regime, modulates redox status among sedentary overweight/obese adults, and whether it has adjunctive effects when combined with selenium supplementation. This work investigates the effect of selenium supplementation on antioxidant enzymes gene expression and ROS generation in vitro, and assesses the role of a dietary and exercise intervention in modulating OS and CVD risk in vivo. Monocyte cells were cultured with/out sodium selenite (100 nM) and stimulated with Paraquat/S-Nitroso-N-acetyl-DL-penicillamine (PQ/SNAP, 1 mM/0.7 mM) to induce OS. Treatment with PQ/SNAP significantly increased ROS generation compared to untreated cells, confirming OS induction; whereas selenium supplementation significantly increased GPx1 (146%) and GPx4 gene expression (77%) and reduced ROS production when compared to un-supplemented stressed cells. Preliminary results from the three-armed randomised intervention study, 8 weeks m-HIIT (10 × 1min at 60% peak aerobic power, three days/week) and/or selenium supplementation (100 μg selenomethionine/day), showed that a single m-HIIT bout significantly increased plasma GPx activity 15 min post-exercise and combined interventions reduced OS. Selenium supplementation and m-HIIT may, therefore, be effective in counteracting OS by significantly increasing GPxs expression in an in vitro and in vivo system.