Time Course of Changes in Leptin Levels and their Relationships with Oxidant Status Biomarkers in Pregnant Women with Obesity

Abstract

Introduction: Changes in leptin signaling during obesity are emerging as a potential risk factor leading to pregnancy complications. Increased oxidative stress may also contribute to the adverse outcomes associated with pregnancy in obese women. Although hyperleptinemia and oxidative stress are risk factors of pregnancy complications during obesity, their relationships have not yet been clarified. Aim: To explore the association between leptin and oxidative stress status in maternal obesity and to evaluate the prediction of oxidant biomarkers by maternal leptin in first trimester. Materials and Methods: This longitudinal study included 60 obese pregnant women and 80 controls who were followed during the three trimesters of pregnancy. Oxidative stress parameters such as nitric oxide (NO), superoxide anion (O2), peroxynitrite, Malondialdehyde (MDA), hydroperoxides, and Protein Carbonyl (PC) contents were measured spectrophotometrically. Serum leptin was measured by ELISA assay. Association between leptin and oxidative stress parameters was performed by multiple regression analysis. Results: Plasma leptin (more than 40%) and oxidant marker concentrations (more than 25%) were significantly higher in obese pregnant women compared to control subjects from the first to the last trimester. Two-way repeated measures ANOVA revealed a significant effect for obesity and time on leptin and oxidant levels (F-values 10.42 to 185.25 for obesity effect and 3.01 to 49.35 for time effect; p<0.01). Leptin concentration was correlated to all oxidant markers (p<0.0008) and explained in general 22 to 52% of their variation. Leptin level measured in the 1st trimester permitted estimation of 3rd trimester hydroperoxide, O2, NO, MDA, PC and peroxinitrite concentrations (p-value<0.0001) and accounted for 77.30 to 94.70% of their variation. Conclusion: Obesity during pregnancy is characterised by high concentrations of leptin and oxidant markers. The leptin levels could be used to predict oxidative stress in late gestation. An early identification of women with increased risk of oxidative stress may provide a window of opportunity to improve redox status by antioxidant supplementation.

Keywords

• first trimester leptin
• hydroperoxides
• malondialdehyde
• maternal obesity
• nitric oxide
• peroxynitrite
• pregnancy trimester
• protein carbonyl
• superoxide anion