Placental leptin gene methylation and macrosomia during normal pregnancy

Genetic variation, intrauterine growth, and adverse pregnancy conditions predict leptin gene DNA methylation in blood at birth and 12 months of age

BACKGROUND

Leptin regulates satiety and energy homoeostasis, and plays a key role in placentation in pregnancy. Previous studies have demonstrated regulation of leptin gene (LEP) expression and/or methylation in placenta and cord blood in association with early life exposures, but most have been small and have not considered the influence of genetic variation. Here, we investigated the relationship between maternal factors in pregnancy, infant anthropometry and LEP genetic variation with LEP promoter methylation at birth and 12 months of age.

METHODS

LEP methylation was measured in cord (n = 877) and 12-month (n = 734) blood in the Barwon Infant Study, a population-based pre-birth cohort. Infant adiposity at birth and 12-months was measured as triceps and subscapular skinfold thickness. Cross-sectional regression tested associations of methylation with pregnancy and anthropometry measures, while longitudinal regression tested if birth anthropometry predicted 12-month LEP methylation levels.

RESULTS

Male infants had lower LEP methylation in cord blood (-2.07% average methylation, 95% CI (-2.92, -1.22), p < 0.001). Genetic variation strongly influenced DNA methylation at a single CpG site, which was also negatively associated with birth weight (r = -0.10, p = 0.003). Pre-eclampsia was associated with lower cord blood methylation at another CpG site (-6.06%, 95% CI (-10.70, -1.42), p = 0.01). Gestational diabetes was more modestly associated with methylation at two other CpG units. Adiposity at birth was associated with 12-month LEP methylation, modified by rs41457646 genotype. There was no association of LEP methylation with 12-month anthropometric measures.

CONCLUSIONS

Infant sex, weight, genetic variation, and exposure to pre-eclampsia and gestational diabetes, are associated with LEP methylation in cord blood. Infant adiposity at birth predicts 12-month blood LEP methylation in a genotype-dependent manner. These findings are consistent with genetics and anthropometry driving altered LEP epigenetic profile and expression in infancy. Further work is required to confirm this and to determine the long-term impact of altered LEP methylation on health.

Cord blood leptin DNA methylation levels are associated with macrosomia during normal pregnancy

BACKGROUND

We previously demonstrated an association between placental leptin (LEP) methylation levels and macrosomia without gestational diabetes mellitus (non-GDM). This study further explored the association between LEP methylation in cord blood and non-GDM macrosomia.

METHOD

We carried out a case-control study of 61 newborns with macrosomia (birth weight ≥4000 g) and 69 newborns with normal birth weight (2500-3999 g). Methylation in the LEP promoter region was mapped by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

RESULTS

Average cord blood LEP methylation levels were lower in macrosomia newborns than in control newborns (P < 0.001). Eleven CpG sites were associated with macrosomia. Multivariate logistic regression revealed that low LEP methylation levels [adjusted odds ratio (AOR) = 2.84, 95% confidence interval (CI): 1.72-4.17], high pre-pregnancy body mass index (AOR = 7.44, 95% CI: 1.99-27.75), long gestational age (AOR = 3.18, 95% CI: 1.74-5.79), high cord blood LEP concentration (AOR = 2.25, 95% CI: 1.34-3.77), and male newborn gender (AOR = 3.91, 95% CI: 1.31-11.69) significantly increased the risk of macrosomia.

CONCLUSIONS

Lower cord blood LEP methylation levels and certain maternal and fetal factors are associated with non-GDM macrosomia.

Birth weight is associated with placental fat mass- and obesity-associated gene expression and promoter methylation in a Chinese population

OBJECTIVE

To explore the relationship between birth weight and fat mass- and obesity-associated (FTO) gene expression and promoter methylation status in the Chinese population.

METHODS

Seventy-five neonates and their mothers were recruited from Yuying Children's Hospital of Wenzhou Medical University. Subjects were divided into three groups by birth weight: low (< 3,500 g, n = 20), medium (3,500-3,999 g, n = 30) and high (≥ 4,000 g, n = 25). Placental FTO transcript levels and promoter methylation were determined by quantitative PCR and Sequenom MassARRAY®.

RESULTS

Placental FTO mRNA expression was significantly increased in the high- and medium-weight groups compared to the low-weight group (p = 0.023). Methylation rates of CpG11 sites were significantly decreased in high-birth weight newborns (p = 0.018). Multiple linear regressions showed placental FTO mRNA, maternal pre-pregnancy body mass index (BMI) and CpG11 methylation rate were independently associated with increased fetal birth weight. Additionally, FTO mRNA expression was negatively associated with CpG6.7.8.9 methylation in mothers that underwent C-section.

CONCLUSIONS

High placental FTO expression is associated with increased birth weight in Chinese neonates, and FTO promoter methylation level at a specific CpG site is negatively associated with birth weight. Further work is needed to determine the functionality of this CpG site in placentas.