Endothelial-dependent and independent vasodiatation; an index for endothelial dysfunction in women with previous gestational diabetes mellitus

Aim: This work was intended to assess whether healthy women with a history of gestational diabetes mellitus [GDM] may have abnormalities in endothelial function at a very early stage before glucose intolerance occurs. Subjects and the work included 45 subjects classified into 3 groups; I] included 15 obese women with previous GDM, II] included 15 nonobese women with previous GDM and III] included 15 nonobese healthy women as controls. All women were subjected to the following: thorough history taking, full clinical examination, laboratory investigations including serum uric acid, glycosylated haemoglobin, plasma endothelin-1 and complete lipid profile "total cholesterol, triglycerides, HDL-C and LDL-C". Oral glucose tolerance test [OGTT] was done using 75g glucose. Insulin sensitivity index and relative resistance for insulin were estimated during OGTT. The vasodilatory responses of the brachial artery during reactive hyperemia [endothelium-dependent Vasodilatation], and after nitroglycerine administration [endothelium-independent Vasodilatation] were measured using high-resolution echo-Doppler ultrasound 3-6 months after the last delivery. Flow mediated dilatation [FMD] was significantly and equally decreased in both groups of women with previous GDM, compared with control subjects [1.6 +/- 3.7% in the nonobese GDM group and 1.6 +/- 2.5% in the obese GDM group versus 10.3 +/- 4.4% in control subjects, P <0.05]. FMD correlated inversely and significantly with serum uric acid levels, BMI, serum total cholesterol, plasma endothelin-1 and relative resistance for insulin. Nitrate-induced dilatation [NID] was significantly decreased only in the obese GDM group compared with controls [21.4 +/- 5.1% versus 27.9 +/- 9.5%, P < 0.05]. OGTT was within normal range in all groups, although glucose concentrations at 30 and 60 min were significantly higher in both GDM groups, and glucose at fasting time, 90 and 120 min were significantly higher only in obese GDM women. Insulin levels at fasting, 30, 60, 90 and 120 min during the OGTT were significantly higher in obese GDM group. The relative resistance for insulin was significantly higher in the obese GDM group when compared with both the normal and nonobese GDM groups. Glycosylated haemoglobin levels were similar in all groups. Serum uric acid and plasma endothelin-1 were significantly higher in both obese and nonobese GDM women. Total cholesterol, triglycerides and LDL-cholesterol were significantly higher in obese GDM women. Conclusions: Our results suggest that endothelial dysfunction, which is considered as a very early index of atherogenesis, is already present in both obese and nonobese women with a history of GDM, even when they have normal glucose tolerance