Tumor necrosis factor system in insulin resistance in gestational diabetes

The aim of the study was to investigate the pathophysiological role of the tumor necrosis factor (TNF) system in insulin resistance in patients with gestational diabetes (GDM) and during the course of normal pregnancy.

Thirty women with GDM (16-39 gestational weeks), 35 healthy pregnant women (15 first, nine second and 11 third trimester) and 25 healthy age-matched non-pregnant women were studied. Serum TNF-alpha, and its soluble receptors 1 and 2 (sTNFR-1 and -2) were measured.

In non-diabetic pregnant women in the third trimester all measures were significantly higher (P<0.05 or less) than in the first trimester and in non-pregnant women (BMI 27.6 +/- 4.1 (+/- S.D.), 24.1 +/- 2.6, 22.4 +/- 2.4 kg/m(2)), serum TNF-alpha (4.6 +/- 0.6, 4.1 +/- 0.4, 4.1 +/- 0.4 ng/l), sTNFR-1 (2.7 +/- 0.9, 2.0 +/- 0.5, 2.0 +/- 0.1 microg/l), sTNFR-2 (5.6 +/- 2.6, 4.6 +/- 2.1, 3.3 +/- 0.2 microg/l), C-peptide (3.1 +/- 1.7, 1.1 +/- 0.7, 1.1 +/- 0.8 microg/l), and C-peptide:blood glucose ratio (0.6 +/- 0.2, 0.2 +/- 0.1, 0.2 +/- 0.1 microg/mmol). In GDM these measures were even higher than in any subgroup of healthy pregnant women (BMI) (33.4 +/- 6.4 kg/m(2), TNF-alpha) (6.3 +/- 0.6 microg/l), sTNFR-1 (3.0 +/- 0.5 microg/l), sTNFR-2 (10.0 +/- 6.9 microg/l, C-peptide 6.0 +/- 2.7 microg/l, C-peptide:blood glucose ratio: 1.2 +/- 0.5 microg/mmol, P<0.01). Significant (P<0.01) positive linear correlations were found in gestational diabetic and non-diabetic women between serum TNF-alpha, C-peptide levels, and BMI. In gestational diabetic women, in multivariate analysis studying the dependency of C-peptide only BMI remained significant (r(2)=0.67, P=0.01).

Our observation emphasizes the obesity-related component of insulin resistance driven by adipocytokines, such as TNF-alpha and its receptors during the course of normal pregnancy and GDM.