Association of levels of polybrominated diphenyl ethers in two fat compartments with increased risk of insulin resistance in obese individuals

Abstract

Murad Helaleh1, Ilhame Diboun2, Nada Altamimi1, Aishah Latiff1, Mohamed Elrayess1* 1Toxicology and Multipurpose Lab, Anti Doping Laboratory Qatar, Sports City, Doha, Qatar. 2 Department of Economics, Mathematics and Statistics, Birkbeck, University of London, London WC1E 7HX, UK. Corresponding author: melrayess@adlqatar.qaAbstractPolybrominated diphenyl ethers (PBDEs) represent a class of widely utilized flame retardants [1]. With over 200 congeners that vary by the extent of halogenations, various PBDEs can leak freely into the environment [2, 3]. Despite cessation of their manufacturing, concerns of their bioaccumulation remain [4-6] due to their stability in products manufactured before the ban and recycled materials [1]. With their high lipophilicity, PBDEs tend to accumulate in adipose tissue, potentially altering the function of this endocrine organ by increasing lipolysis and decreasing glucose oxidation, causing increased risk of metabolic disease including obesity, insulin resistance and type 2 diabetes [7]. Exposure to PBDE-47, for example, during the early post-natal period was shown to induce disturbance in glucose metabolism causing insulin resistance in susceptible mice [8]. In this study, levels of various PBDEs were assessed in subcutaneous and omental adipose tissues from 33 obese and morbidly obese patients (11 insulin sensitive and 22 insulin resistant) and their correlation with mediators of metabolic disease were established. Our results suggested that out of 22 detectable PBDEs in subcutaneous and omental adipose tissues, PBDE99, 28, 47 and 126 were significantly higher in insulin resistant individuals compared to their insulin sensitive counterparts. When considering PBDEs congeners, penta congeners as a group were also higher in insulin resistant individuals compared to insulin sensitive counterparts, while no significant differences were detected in mono, tri, tertra, hexa, hepta and octa congeners between the two studied groups. This data suggest that accumulation of various PBDEs in human adipose tissues obtained from obese individuals is associated with increased risk of insulin resistance. Further investigation of the functional relevance of these associations is currently underway. This study is partly funded by QNRF's grant number NPRP6-235-1-048.