title: Opposite regulation of interleukin-8 and tumor necrosis factor-alpha by weight loss.
abstract: OBJECTIVE
  To obtain more information on the possible influence of body mass index (BMI) and weight loss on interleukin-8 (IL-8) in plasma and in the adipose tissue. Tumor necrosis factor-alpha (TNF-alpha) was used for comparison and determined in parallel with IL-8.
  
  
  METHODS
  The study was divided into three parts: 1) a cross-sectional study that included 89 subjects; 2) a 20-week intervention study in which 34 healthy obese subjects received a dietary intervention for 8 weeks followed by an additional 12 weeks on a weight-stabilization diet; 3) from this latter study, a subgroup of 8 obese subjects was investigated with a subcutaneous adipose-tissue biopsy.
  
  
  RESULTS
  In the cross-sectional study, plasma levels of TNF-alpha (p < 0.01), but not IL-8, was correlated with BMI. However, in a subgroup (BMI, 20 to 30 kg/m(2)), IL-8 was correlated with BMI (p < 0.01). In the intervention study, weight loss and weight maintenance led to an increase in IL-8 by 30% (p < 0.05) and a decrease in TNF-alpha by 40% (p < 0.001), which were paralleled in the adipose tissue, demonstrating a 2- to 3-fold increase (p < 0.01) and a 40% to 80% decrease (p < 0.01) in IL-8 and TNF-alpha, respectively.
  
  
  CONCLUSIONS
  Weight loss in obese subjects was associated with opposite changes in the secretion and transcription of IL-8 and TNF-alpha in the adipose tissue, as well as in plasma. This could indicate that plasma IL-8 under some conditions may be related to changes in adipose tissue IL-8 production.
authors.affiliation: Department of Endocrinology and Metabolism C, Aarhus Amtssygehus, Aarhus University Hospital and Faculty of Health Sciences, Aarhus University, Denmark. jmb@mail-online.dk
authors.forename: Jens M
authors.initials: JM
authors.lastname: Bruun
authors.forename: Steen B
authors.initials: SB
authors.lastname: Pedersen
authors.forename: Kurt
authors.initials: K
authors.lastname: Kristensen
authors.forename: Bjørn
authors.initials: B
authors.lastname: Richelsen
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000328:Adult; D001706:Biopsy; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D046508:Culture Techniques; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D007328:Insulin / Q000097:blood; D016209:Interleukin-8 / Q000097:blood / Q000235:genetics / Q000378:metabolism*; D020738:Leptin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D015431:Weight Loss
chemical_list: D007328:Insulin; D016209:Interleukin-8; D020738:Leptin; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha