Study of plasma visfatin level in women with gestational diabetes mellitus during and after pregnancy and its relation to insulin sensitivity

The insulin-mimetic adipocytokine visfatin is highly expressed in visceral fat and whose blood levels correlate with obesity. It lowers blood glucose, improves insulin sensitivity, and recently found to act as an insulin analogue on the insulin receptors. It has been associated with insulin resistance in some studies and regulated by glucose. To evaluate the role of visfatin in GDM, typically associated with increased insulin resistance, we determined visfatin levels in women with GDM and in healthy pregnant controls. Furthermore, visfatin concentrations were investigated after delivery in a subgroup of women with GDM. 30 women with GDM [group I] and 15 age-matched healthy pregnant controls [group II] at 24-28 weeks of gestation were included in the study. All women were subjected to full history taking, complete physical examination and anthropometric measures including BMI and WHR. Venous blood samples for lipid profile, glucose, insulin and visfatin concentrations were taken 1 hour before a standard 75g OGTT and was carried out after overnight fast. Venous blood samples were repeated for glucose, insulin and visfatin 30, 60, 120 minutes after an oral glucose load. Insulin sensitivity was estimated using ISI derived from OGTT. A subgroup of 15 women with GDM [group III] was investigated for all these parameters 2 weeks after delivery. Fasting plasma visfatin concentrations were significantly higher in the gestational diabetes mellitus group during the course of pregnancy [69.04 +/- 18.41 ng/ml] than in healthy pregnant control group [31.22 +/- 24.74 ng/ml] [P<0.05]. The fasting plasma levels of visfatin showed significant drop in GDM women 2 weeks after labour [45.86 +/- 6.89 ng/ml] than during the course of pregnancy [69.04 +/- 18.41 ng/dl] [P<0.05]. The glucose-induced changes in visfatin and insulin calculated by AUC were significantly higher in GDM group during pregnancy than in healthy normal controls. The mean values of the area under the curve for glucose, insulin and visfatin curves showed significant reduction in GDM women 2 weeks after labour [P<0.05]. Significant positive correlations were detected between fasting visfatin and WHR, fasting glucose, as well as fasting insulin in GOM women during pregnancy and 2 weeks after labour. Fasting visfatin levels were negatively and significantly correlated with peripheral insulin sensitivity index in the three studied groups [P<0.05]. The precise significance of our findings indicates that adipocytokine visfatin may play a role in the pathogenesis of gestational diabetes mellitus. However, the study of the regulation of visfatin in GDM merits further considerations and further experiments are needed to clarify its role in such disease