G. Winkler et al., Elevated serum TNF-alpha level as a link between endothelial dysfunction and insulin resistance in normotensive obese patients, DIABET MED, 16(3), 1999, pp. 207-211
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 pat
ients with different types of obesity.
Patients and methods Fasting serum TNF-alpha immunoreactive concentration (
enzyme-linked immunosorbent assay, ELISA) and bioactivity (L929 cell cytoto
xicity assay), endothelin-1 and C-peptide levels (radioimmunoassay, RIA) we
re measured in 15 patients with android- and 13 patients with gynoid-type o
besity 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, on
ly 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 n
ot 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 res
istance and vascular dysfunction in patients with android obesity.