Study question: Do global gene expression profiles differ between non-implanted embryos and embryos resulting in live birth?
Summary answer: From the set of 181 genes that were the most differentially expressed, 145 genes were upregulated in trophectoderm (TE) biopsies from embryos that did not implant (TE(-) biopsies), whereas only 36 genes showed an upregulation in the TE samples from embryos resulting in live birth (TE(+) biopsies).
What is known already: Results obtained from animal models point towards the existence of a gene expression profile that is distinguishably different in viable embryo compared with non-viable embryos. Knowledge of human embryo transcripts is limited, in particular with regard to a relation between gene expression and clinical outcome.
Study design, size, duration: Embryos from infertile couples presenting for infertility treatment at the Fertility Clinic Aarhus University Hospital. TE biopsies were obtained on Day 5 and the embryos transferred on Day 6
Participants/materials, setting, methods: RNA from three biopsies (TE(+)) obtained from blastocysts resulting in live birth and three biopsies (TE(-)) obtained from non-implanting blastocysts was subjected to genome wide sequencing (NGS). qPCR analyses was performed on a set of independently collected TE biopsies.
Main results and the role of chance:
All reads were mapped to the human reference genome (hg19) and filtered. RPKM values were calculated and analysed. Using a set of filtering criteria, we obtained a list of 181 genes that were the most differentially expressed. When these genes were grouped as specific to either TE(+) or TE(-) biopsies, it showed that almost 80% (145 genes) of the genes were upregulated in TE(-) biopsies, whereas only 20% (36 genes) showed an upregulation in the TE(+) samples compared to the TE(-) biopsies. The RNA sequencing results were suppoted by qPCR of three selected genes (DNAJC1, SPEN and CALR) that were upregulated in the TE(-) biopsy compared to the TE(+) biopsy.
Limitations, reasons for caution: Results need to be confirmed on a larger set of biopsies.
Wider implications of the findings: The distinct differences in expressed genes between implanted and non-implanted embryos that were morphologically similar suggest the presence of functional, but visually undetectable differences. Our study contribute with new knowledge of which gene-families plays an important role in implantation
Study funding/competing interest(s): The study was conducted with support from Aarhus University, The Danielsen Foundation, AP Møller Foundation, Lipperts Foundation, Segels Foundation, The Toyota Foundation. Research at the Fertility Clinic, Aarhus University Hospital is supported by an unrestricted grant from MSD and Ferring.
Trial registration number: The study was part of a study registered at ClinicalTrial.gov with accession number NCT01139268


Oral præsentation. Forfattere: Kirkegaard, K.; Villesen, P.; Jensen, JM.; Hindkjær, JJ.; Kølvraa, S.; Ingerslev HJ. and Lykke-Hartmann, K.