Plasma apelin levels and apelin/APJ mRNA expression in patients with gestational diabetes mellitus

Aims and methods: Apelin is a novel adipokine identified as an endogenous ligand of the G protein-coupled receptor APJ. In this study we compared plasma apelin concentrations in 101 patients with gestational diabetes (GDM) and 101 women with normal glucose tolerance (NGT) between 24 and 32 weeks of gestation (Group 1), as well as in 20 women with GDM and 16 subjects with NGT at term (Group 2). Apelin and APJ mRNA expression in subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT) and placental tissue were also measured in Group 2, using quantitative real-time PCR. Results: There were no significant differences in plasma apelin levels between the women with GDM and NGT (Group 1: 1555.6 [1281.2-1804.2] pg/ml vs 1656.5 [1430.2-1852.1] pg/ml, Group 2: 1607.9 [1453.4-1768.7] pg/ml vs; 1493.8 [1316.8-1956.7] pg/ml) nor in apelin and APJ mRNA expression in SAT, VAT and placental tissue. Apelin mRNA expression was approximately 10 fold higher in placental than in adipose tissue (p < 0.0001). Apelin and APJ mRNA expression correlated significantly in SAT (R = 0.45, p = 0.03), VAT (R = 0.69, p = 0.003) and placental tissue (R = 0.37, p = 0.03). Conclusions: No associations between circulating apelin or apelin/APJ mRNA expression and GDM or the indices of insulin resistance were noted in our study. (C) 2009 Elsevier Ireland Ltd. All rights reserved.