Elevated serum TNF-alpha level as a link between endothelial dysfunction and insulin resistance in normotensive obese patients

Diabet Med. 1999 Mar;16(3):207-11. doi: 10.1046/j.1464-5491.1999.00052.x.


Aims: The aim of the study was to analyse the role of tumour necrosis factor-alpha (TNF-alpha) in insulin resistance and endothelial dysfunction in patients with different types of obesity.

Patients and methods: Fasting serum TNF-alpha immunoreactive concentration (enzyme-linked immunosorbent assay, ELISA) and bioactivity (L929 cell cytotoxicity assay), endothelin-1 and C-peptide levels (radioimmunoassay, RIA) were measured in 15 patients with android- and 13 patients with gynoid-type obesity and 15 lean healthy controls with normal glucose tolerance and blood pressure.

Results: Significantly (P<0.01) higher TNF-alpha concentration (8.92 +/- 0.44 pg/ml) and bioactivity (3.12 +/- 0.48 U/ml) were found in patients with android obesity as compared to patients with gynoid obesity (7.01 +/- 0.30 pg/ml, 0.97 +/- 0.11 U/ml) and to the lean controls (6.88 +/- 0.26 pg/ml, 0.88 +/- 0.08 U/ml). Serum endothelin-1 (5.38 +/- 0.30 pg/ml) and C-peptide levels (4.82 +/- 0.71 ng/ml) were also significantly higher (P < 0.01) in patients with android-type obesity than in controls (3.89 +/- 0.43 pg/ml, 1.46 +/- 0.25 ng/ml, respectively). In patients with gynoid-type obesity, only the C-peptide levels proved to be significantly higher (2.84 +/- 0.29 ng/ ml). Endothelin-1 levels, although were found to be slightly higher, did not differ statistically from in controls (4.56 +/- 0.31 pg/ml). There were significant positive linear correlations only in patients with android-type obesity between TNF-alpha, body mass index (BMI), serum endothelin-1 and C-peptide levels.

Conclusions: TNF-alpha may be one of the factors contributing to insulin resistance and vascular dysfunction in patients with android obesity.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Body Mass Index
  • C-Peptide / blood
  • Case-Control Studies
  • Endothelin-1 / blood
  • Endothelium, Vascular / physiopathology*
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Insulin Resistance*
  • Linear Models
  • Obesity / blood
  • Obesity / physiopathology*
  • Tumor Necrosis Factor-alpha / metabolism*


  • C-Peptide
  • Endothelin-1
  • Tumor Necrosis Factor-alpha