Background: The nutritional and hormonal state in utero may be a link between maternal obesity and obesity in the offspring. The gene expression in placentae in pregnancies complicated by diabetes is reduced for leptin, but increased for ghrelin. It is not known whether these genes expressions in placentae are altered in maternal obesity.
Objectives and hypotheses: To compare obese and normal-weight women and their children concerning gene expressions of leptin and ghrelin in placentae; leptin, ghrelin, adiponectin, and C-peptide levels in cord blood, birth size and postnatal growth. Changes in the expression of these adipocytokines may lead to an altered hypothalamic sensitivity to leptin and ghrelin resulting in an increased risk of obesity in the offspring.
Method: 32 women with pre-pregnancy obesity, but otherwise healthy, were compared to 32 matched, normal-weight controls. Full-term placenta biopsies were analysed with qPCR for leptin mRNA and ghrelin mRNA. Cord blood samples were examined with ELISA for leptin, ghrelin, adiponectin, and C-peptide concentrations. Birth size and postnatal growth of the children were collected from clinical registers at the Child Health Care Units.
Results: The leptin and ghrelin gene expressions in placentae did not differ between obese and normal-weight women. The leptin concentration in cord blood was higher in children of obese mothers (P=0.021). It correlated with birth weight Z-score (r=0.467, P<0.001) and C-peptide level in cord blood (r=0.446, P<0.001). Children of obese women were slightly heavier at birth, but postnatal growth did not differ between groups. Children with birth weight ≤−0.67 Z-score had higher ghrelin levels in cord blood than heavier children (P=0.042). The leptin level in cord blood correlated negatively with weight gain at 6 months (r=−0.332, P=0.009). The ghrelin level in cord blood correlated with weight gain at 3 months in girls (r=0.611, P=0.001), but not in boys. The adiponectin level in cord blood correlated negatively with length gain at 3 years in the obese group (r=−0.571, P=0.033), but not in the normal-weight group.
Conclusion: Leptin and ghrelin placental gene expressions are not altered in obese women, but foetal adipocytokine production may influence early postnatal growth, possibly by influencing hunger signalling or insulin levels.
Funding: This work was supported by the Research Committee in Region Örebro County and the Key Fundation (Nyckelfonden) at Örebro University Hospital.
01 Oct 2015 - 03 Oct 2015