RT Journal Article SR Electronic T1 Adipose Tissue Is a Major Source of Interleukin-1 Receptor Antagonist JF Diabetes JO Diabetes FD American Diabetes Association SP 1104 OP 1110 DO 10.2337/diabetes.52.5.1104 VO 52 IS 5 A1 Juge-Aubry, Cristiana E. A1 Somm, Emmanuel A1 Giusti, Vittorio A1 Pernin, Agnès A1 Chicheportiche, Rachel A1 Verdumo, Chantal A1 Rohner-Jeanrenaud, Françoise A1 Burger, Danielle A1 Dayer, Jean-Michel A1 Meier, Christoph A. YR 2003 UL http://diabetes.diabetesjournals.org/content/52/5/1104.abstract AB The secreted form of the interleukin-1 receptor antagonist (IL-1Ra) is an acute-phase protein intervening in the counterregulation of inflammatory processes. We previously showed that this cytokine antagonist is upregulated in the serum of obese patients, correlating with BMI and insulin resistance. In this study, we examined the expression pattern of IL-1Ra and showed that it is highly expressed not only in liver and spleen, but also in white adipose tissue (WAT), where it is upregulated in obesity. In WAT of obese humans, IL-1Ra was also markedly increased. Moreover, human WAT explants secreted IL-1Ra into the medium, a process that could be stimulated fivefold by interferon-β. Finally, lipopolysaccharide administration induced a long-lasting expression of IL-1Ra in mouse WAT, suggesting that adipose tissue is an important source of IL-1Ra in both obesity and inflammation. In summary, we demonstrated that WAT is one of the most important sources of IL-1Ra quantitatively, suggesting that this tissue could represent a novel target for anti-inflammatory treatment. Moreover, it can be speculated that IL-1Ra, whose production is markedly increased in WAT in obese individuals, contributes further to weight gain because of its endocrine and paracrine effects on the hypothalamus and adipocytes, respectively.