Assisted Reproductive Technologies (ART) are invaluable for the increasing number of women who require interventions to treat their infertility. Nevertheless, ART-conceived children are at increased risk for loss-of-imprinting disorders resulting from epigenetic errors, abnormal growth, congenital malformations, and postnatal cardiac and metabolic disorders. Such problems likely arise because ART procedures take place when the mammalian embryo is being epigenetically reprogrammed. Because it is difficult to conduct studies using human embryos, a mouse model system, which anticipated some risks associated with ART, will be used to assess the effect of ART interventions on placental morphology, imprinted gene regulation, growth, metabolic and cardiac phenotypes of the offspring, and epigenetic gene regulation, including DNA methylation and chromatin structure genome-wide. Presently, preliminary evidence suggests that frozen embryos transferred into unstimulated women have less perinatal morbidity than fresh cycles but conflicting data suggest adverse outcomes associated with frozen embryos.
Specific Aim 1 will determine the effects of embryo vitrification and maternal hormonal environment on offspring outcome of IVF-generated embryos. Moreover, preimplantation genetic screening (PGS) is being increasingly employed in the absence of research assessing the consequences of blastomere biopsy.
Specific Aim 2 will investigate the phenotypes and epigenetic profiles of the placenta and ART offspring derived when PGS is used. Finally, data from our human placental studies demonstrate alterations in DNA methylation in genes critical to early placentation, fetal growth, and adult metabolism.
Specific Aim 3 will translate these data to our animal ART model to determine the role of specific genes in adverse outcomes associated with IVF. The role of Grb10 in IVF-associated changes in fetal growth, placentation, and vasculogenesis using a mouse model will be initially assessed. Results of these experiments will provide information regarding the linkage between epigenetic changes and health of offspring conceived by ART. These findings may also suggest experimental modifications to ART procedures that can improve offspring outcomes.
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