¹The Lundberg Laboratory for Diabetes Research, Department of Internal Medicine, The Sahlgrenska Academy at Göteborg University, Göteborg, Sweden

Correspondence: Dr VR Sopasakis, Lundberg Laboratory for Diabetes Research, Department of Internal Medicine, Sahlgrenska University Hospital, SE-413 45 Göteborg, Sweden. E-mail: victoria.rotter@medic.gu.se

Received 14 November 2004; Revised 10 March 2005; Accepted 17 March 2005; Published online 24 May 2005.

Abstract

Explants of human adipose tissue from nonobese subjects were cultured for 24 h with or without the presence of 20 ng/ml TNF. Gene expression and/or medium concentrations of interleukin (IL)-1, IL-1 receptor antagonist (IL-1 RA), TNF, IL-6, IL-8, resistin, PAI-1 and leptin were analysed. TNF increased the mRNA levels of TNF itself as well as IL-6, IL-8, IL-1 and PAI-1, but not leptin. The medium concentrations of IL-1 RA, IL-6 and IL-8 were markedly increased by TNF while no measurable release of TNF, resistin or IL-1 to the medium was found. Thus, human adipose tissue from nonobese individuals releases substantial amounts of IL-6, IL-8 and IL-1 RA and the gene expression of these cytokines, like that of IL-1 and PAI-1, is regulated by TNF. However, since neither TNF, resistin or IL-1 was found in the culture medium, such a regulatory effect by TNF on adipose tissue in vivo is likely to be mediated through a paracrine mechanism where invaded inflammatory cells may play a critical role.