Maternal obesity during pregnancy increases the risk of hypertension, gestational diabetes and abnormalities in fetal growth with higher infant birth weight and BMI in both early and late childhood. Extensive literature provides evidence for epigenetic programming of the developing fetus in response to the maternal metabolic milieu, but there is minimal direct evidence that changes in the fetal environment can alter the epigenome. The proposed study will test the hypothesis that significant weight loss prior to conception will improve the intrauterine metabolic environment as reflected in the maternal metabolome and inflammation-related proteome and result in changes in methylation patterns in cord blood leukocytes. To test this hypothesis, three Specific Aims are proposed.
Aim 1, will examine the metabolic intrauterine environment in 300 obese women (BMI>30 kg/m2 ? 45 kg/m2) who will be randomized to either Very Low Energy Diet (VLED) targeting a >15% body weight loss or Standard of Care (SOC) interventions. Along with 120 lean women (LEAN) serving as comparators, VLED and SOC women will undergo extensive prepregnancy clinical and physiological phenotyping and blood collections. Obese women will undergo additional phenotyping after weight loss and all women will have additional testing at each trimester. We expect 87 offspring in each group. Fetal growth will be assessed by ultrasound and offspring birth weight (Ponderal index), adiposity (Pea Pod Air Displacement Plethysmography).
In Aim 2, plasma metabolomics and (hybrid targeted/untargeted and lipidomics) and inflammatory markers will be used to assess intervention associated changes in VLED and SOC women and compared to VLED women. To assess the intrauterine environment, metabolomic profiles and inflammatory proteome will be measured in the first trimester and at term in all mothers and in fetal cord blood. Multivariate computational models will assess the association of maternal and neonate metabolome and inflammatory markers to fetal growth and newborn weight and adiposity.
In Aim 3, DNA methylation patterns and RNA-seq will be obtained from fetal cord blood lymphocytes of all offspring. Differences in methylation patterns between VLED, SOC and LEAN will be assessed and changes in mRNA levels will be determined to assess the effect of methylation on gene expression. Multivariate analysis of methylation patterns will be related to the metabolome and to fetal growth and birth outcomes. Using sparse multivariate factor analysis regression model (smFARM) and other statistical approaches, we will determine how the maternal metabolome and proteome is associated with cord blood DNA methylation and investigate whether fetal growth or birth weight and other outcomes are mediated by specific metabolites. The results of these studies will provide the first prospective assessment of the benefit of preconception weight loss on the intrauterine environment and molecular changes in the newborn and will provide a potential pathway from maternal intrauterine environment and programmed changes in weight and metabolic status in offspring.
The study will assess the feasibility of improving the metabolic health of obese women, and their offspring, by implementing a relatively short, aggressive weight loss intervention. The study is also designed to find specific molecules in the blood of obese women that could be changed by diet or other approaches that could reduce the risk of their children becoming obese in childhood or even in adulthood.