The prolonged disease state of infertility is associated with embryonic epigenetic dysregulation

Abstract

Objective: To evaluate the epigenetic consequence of a prolonged disease state of infertility in euploid blastocysts.

Design: Methylome analysis as well as targeted imprinted methylation and expression analysis on individual human euploid blastocysts examined in association with duration of patient infertility and time to live birth.

Setting: Research study.

Patient(s): One hundred four surplus cryopreserved euploid blastocysts of transferrable-quality were donated with informed patient consent and grouped based on time to pregnancy (TTP).

Intervention(s): None MAIN OUTCOME MEASURE(S): The Methyl Maxi-Seq platform (Zymo Research) was used to determine genome-wide methylation, while targeted methylation and expression analyses were performed by pyrosequencing and quantitative real-time polymerase chain reaction, respectively. Statistical analyses used Student's t test, 1-way ANOVA, Fisher's exact test, and pairwise-fixed reallocation randomization test, where appropriate.

Result(s): The methylome analysis of individual blastocysts revealed significant alterations at 6,609 CpG sites associated with prolonged infertility (≥60 months) compared with those of fertile controls (0 months). Significant CpG alterations were localized to numerous imprinting control regions and imprinted genes, and several signaling pathways were highly represented among genes that were differentially methylated. Targeted imprinting methylation analysis uncovered significant hypomethylation at KvDMR and MEST imprinting control regions, with significant decreases in the gene expression levels upon extended TTP (≥36 months) compared to minimal TTP (≤24 months).

Conclusion(s): The prolonged disease state of infertility correlates with an altered methylome in euploid blastocysts, with particular emphasis on genomic imprinting regulation, compared with assisted reproductive technologies alone.

Keywords: Genomic imprinting; epigenetic dysregulation; expression; infertility; methylation.