Elevated levels of interleukin 6 are reduced in serum and subcutaneous adipose tissue of obese women after weight loss

J Clin Endocrinol Metab. 2000 Sep;85(9):3338-42. doi: 10.1210/jcem.85.9.6839.

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.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / metabolism*
  • Adult
  • Aged
  • Diabetes Mellitus, Type 2 / metabolism
  • Diet, Reducing
  • Female
  • Humans
  • Interleukin-6 / blood
  • Interleukin-6 / metabolism*
  • Leptin / blood
  • Middle Aged
  • Obesity / metabolism*
  • Tumor Necrosis Factor-alpha / metabolism
  • Weight Loss / physiology*

Substances

  • Interleukin-6
  • Leptin
  • Tumor Necrosis Factor-alpha