title: Elevated levels of interleukin 6 are reduced in serum and subcutaneous adipose tissue of obese women after weight loss.
abstract: The aim of this study was to investigate the potential role of adipose cytokines in the obesity-associated insulin resistance. To that end, we compared: 1) serum concentrations of interleukin 6 (IL-6), tumor necrosis factor alpha (TNFalpha), and leptin in eight healthy lean control females and in android obese female without (n = 14) and with (n = 7) type 2 diabetes; and 2) the levels of these cytokines both in serum and in sc adipose tissue in the 14 obese nondiabetic women before and after 3 weeks of a very low-calorie diet (VLCD). As compared with lean controls, obese nondiabetic and diabetic patients were more insulin resistant and presented increased values for leptin, IL-6, TNFalpha, and C-reactive protein. In the whole group, IL-6 values were more closely related to the parameters evaluating insulin resistance than leptin or TNFalpha values. VLCD resulted in weight loss and decreased body fat mass (approximately 3 kg). Insulin sensitivity was improved with no significant change in both serum and adipose tissue TNFalpha levels. In contrast, VLCD induced significant decreases in IL-6 and leptin levels in both adipose tissue and serum. These results suggest that, as for leptin, circulating IL-6 concentrations reflect, at least in part, adipose tissue production. The reduced production and serum concentrations after weight loss could play a role in the improved sensitivity to insulin observed in these patients.
authors.affiliation: Service de Biochimie, Hôpital de la Salpêtrière, Paris, France. jean-philippe.bastard@tnn.ap-hop-paris.fr
authors.forename: J P
authors.initials: JP
authors.lastname: Bastard
authors.forename: C
authors.initials: C
authors.lastname: Jardel
authors.forename: E
authors.initials: E
authors.lastname: Bruckert
authors.forename: P
authors.initials: P
authors.lastname: Blondy
authors.forename: J
authors.initials: J
authors.lastname: Capeau
authors.forename: M
authors.initials: M
authors.lastname: Laville
authors.forename: H
authors.initials: H
authors.lastname: Vidal
authors.forename: B
authors.initials: B
authors.lastname: Hainque
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism; D004038:Diet, Reducing; D005260:Female; D006801:Humans; D015850:Interleukin-6 / Q000097:blood / Q000378:metabolism*; D020738:Leptin / Q000097:blood; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015431:Weight Loss / Q000502:physiology*
chemical_list: D015850:Interleukin-6; D020738:Leptin; D014409:Tumor Necrosis Factor-alpha