Level of ex vivo interleukin 6 expression in human peripheral fat compared with other tissues

Objectives: Adipose tissue is able to secrete a variety of active mediators into the circulation. One of these is Interleukin 6 (IL6). IL6 may play a causal role in the development of atherosclerosis. It has therefore been suggested that IL6 may form part of the link between obesity and vascular disease. The aim of this study was to quantify the relative IL6 expression in adipose tissue compared to other tissues.Methods: Tissue (vein, fat, muscle, blood) was collected from 32 patients undergoing varicose vein surgery. RNA was extracted and mRNA measured using RT-PCR relative quantification. The mean relative IL6 mRNA levels were compared between tissues using the Mann Whitney U test and the independent t-test. Tissue levels were compared for individuals using the Wilcoxon signed rank test.Results: Mean relative IL6 mRNA levels (mean ± SEM) were significantly greater in adipose tissue 44.8 ± 16.1 than in other tissues (leukocytes 1.1 ± 0.3, vein 2.0 ± 0.8, muscle 0.06 ± 0.03: p < 0.001). mRNA expression levels were also significantly higher in fat than in all other tissue types in individuals (p < 0.001).Conclusions: IL6 mRNA expression is significantly higher in adipose than in many other tissues known to express IL6