Gene Expression Human Preimplantation Embryos

Differential gene expression in preimplantation embryos has been documented, but few focused studies have been done to compare differential expression in human embryos after embryonic genome activation and specifically how they relate to blastocyst development. We hypothesized that blastocyst stage embryos would differentially express genes in pathways important in cell division, mobilization, and processes important in embryo implantation including endometrial apposition, adhesion, and invasion. We analyzed gene expression in 6 preimplantation human embryos. Embryos studied were previously cryopreserved, supernumerary human embryos donated by couples who completed their family building through in vitro fertilization and had given specific consent for use in research. Embryos cryopreserved at the pronuclear stage were thawed and cultured to cleavage (Day 3) or blastocyst (Day 5) stage. Differential gene expression was first obtained through Affymetrix gene expression microarrays and then validated both in silico using the Gene Expression Omnibus and in vitro with RT-qPCR. Compared to cleavage stage embryos, blastocyst stage embryos differentially expressed 51 genes (p < 0.001), with overrepresentation in amoebiasis pathways and pathways in cancer. Human embryos studied were previously cryopreserved, supernumerary human embryos donated by couples who completed their family building through in vitro fertilization and had given specific consent for use in research. Human embryos cryopreserved at the pronuclear stage were thawed and cultured to cleavage (Day 3) or blastocyst (Day 5) stage. Differential gene expression was first obtained through Affymetrix gene expression microarrays (3 individual cleavage stage embryos, and 3 individual blastocyst stage embryos). These findings were then validated both in silico using the Gene Expression Omnibus and in vitro with RT-qPCR on a new set of human embryos.