Abstract
STUDY QUESTION
Which transcriptomic alterations in mid-luteal endometrial scratch biopsies, taken prior to the assisted reproductive treatment (ART) treatment cycle are associated with unsuccessful pregnancy?
SUMMARY ANSWER
Dysregulated interleukin-17 (IL-17) pathway components are demonstrated in women who fail to become pregnant after ART.
WHAT IS KNOWN ALREADY
Implantation failure is now recognised as a critical factor in unexplained infertility and may be an important component of failed ART.
STUDY DESIGN, SIZE, DURATION
Using a prospective longitudinal study design, 29 nulliparous women with unexplained infertility undergoing ART were recruited between October 2016 and February 2018. Mid-luteal stage endometrium and matched serum samples were collected, and patients underwent a single embryo transfer in the subsequent cycle. RNA-seq analysis of endometrial biopsies was performed on the discovery cohort (n = 20).
PARTICIPANTS/MATERIALS, SETTING, METHODS
Gene set enrichment analysis of the differentially expressed genes (DEGs) was performed. Endometrium and serum were then prepared for IL-17A analysis by ELISA.
MAIN RESULTS AND THE ROLE OF CHANCE
There were 204 differentially expressed protein-coding genes identified in tissue from women who became pregnant (n = 9) compared with tissue from women who failed to become pregnant (n = 11) (false discovery rate; P < 0.05). Of the 204 DEGs, 166 were decreased while 38 were increased in the pregnant compared to the non-pregnant groups. Gene set enrichment analysis of the DEGs identified an over-representation of IL-17 and Pl3K-Akt signalling pathways. All the DEGs within the IL-17 signalling pathway (MMP3, MMP1, IL1β, LCN2, S100A9 and FOSL1) demonstrated decreased expression in the pregnant group. Serum IL-17 protein levels were increased in the non-pregnant discovery cohort (n = 11) and these findings were confirmed a validation cohort (n = 9).
LIMITATIONS, REASONS FOR CAUTION
Limitations of our study include the cohort size and the lack of aneuploidy data for the embryos; however, all embryos transferred were single good or top-quality blastocysts.
WIDER IMPLICATIONS OF THE FINDINGS
These findings demonstrate dysregulated IL-17 pathway components in women who fail to become pregnant after ART. Elevated serum levels of the pro-inflammatory cytokine IL-17 may predict failure of ART in women with unexplained infertility. Future trials of anti-IL-17 therapies in this cohort warrant further investigation.
STUDY FUNDING/COMPETING INTEREST(S)
Funding from the UCD Wellcome Institutional Strategic Support Fund, which was financed jointly by University College Dublin and the SFI-HRB-Wellcome Biomedical Research Partnership (ref 204844/Z/16/Z), is acknowledged. The authors have no competing interests.
TRIAL REGISTRATION NUMBER
NA.
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