DNA methylation differences between in vitro- and in vivo-conceived children are associated with ART procedures rather than infertility

Abstract

BackgroundWe, and others, have demonstrated previously that there are differences in DNA methylation and transcript levels of a number of genes in cord blood and placenta between children conceived using assisted reproductive technologies (ART) and children conceived in vivo. The source of these differences (the effect of ART versus the underlying infertility) has never been determined in humans. In this study, we have attempted to resolve this issue by comparing placental DNA methylation levels at 37 CpG sites in 16 previously identified candidate genes in independent populations of children conceived in vivo (‘fertile control’ group) with ART children conceived from two groups: either autologous oocytes with infertility in one or both parents (‘infertile ART’ group) or donor oocytes (obtained from young fertile donors) without male infertility (‘donor oocyte ART’ group).ResultsOf the 37 CpG sites analyzed, significant differences between the three groups were found in 11 CpGs (29.73 %), using ANOVA. Tukey’s post hoc test on the significant results indicated that seven (63.63 %) of these differences were significant between the donor oocyte ART and fertile control groups. In addition, 20 of the 37 CpGs analyzed had been identified as differentially methylated between ART and fertile control groups in an independent population in a prior study. Of these 20 CpG sites, 9 also showed significant differences in the present population. An additional 9 CpGs were found to be significantly different between the two groups. Of these 18 candidate CpGs, 12 CpGs (in seven candidate genes) also showed significant differences in placental DNA methylation levels between the donor oocyte ART and fertile control groups.ConclusionsThese data suggest strongly that the DNA methylation differences observed between ART and in vivo conceptions are associated with some aspect of ART protocols, not simply the underlying infertility.Electronic supplementary materialThe online version of this article (doi:10.1186/s13148-015-0071-7) contains supplementary material, which is available to authorized users.

Assisted reproductive technology alters deoxyribonucleic acid methylation profiles in bloodspots of newborn infants

“…Across limited loci the three assisted conception groups exhibited marked differences from the natural conception group, supporting the view that there are subtle epigenetic changes in children from parents who sought fertility treatment, relative to those conceived naturally. Consistent with this tenet, 4 of the 18 candidate CpG sites altered in placental tissue from children born to fertile parents compared with infertile parents (27) are located in or near significant clusters of two imprinted genes, growth factor receptor-bound protein 10 (GRB10) and necdin (NDN). Clustering analysis recapitulates the hypomethylation of placental GRB10 CpG sites in bloodspots of ART children compared with fertile controls (27) but is not congruent with those reported for NDN.…”

“…Consistent with this tenet, 4 of the 18 candidate CpG sites altered in placental tissue from children born to fertile parents compared with infertile parents (27) are located in or near significant clusters of two imprinted genes, growth factor receptor-bound protein 10 (GRB10) and necdin (NDN). Clustering analysis recapitulates the hypomethylation of placental GRB10 CpG sites in bloodspots of ART children compared with fertile controls (27) but is not congruent with those reported for NDN. The discordance likely reflects differences in tissue-specific DNA methylation between peripheral blood and placenta.…”

“…The health risks and disease phenotypes observed in ART-conceived children in part may result from underlying epigenetic aberrations presented by parental infertility or ART itself. However, evidence for concerted epigenetic changes in the ART population (23)(24)(25)(26)(27)(28) is countered by a number of studies asserting that the epigenome of ART-conceived offspring is essentially unchanged (29)(30)(31)(32).…”

Oviduct: roles in fertilization and early embryo development

“…A recent study using cord blood and placentas collected from the children conceived by ART and naturally conceived children showed that the source of alteration in DNA methylation status is a result of ART procedures, rather than the underlying fertility of the parents (Song et al 2015). Hiura and coworkers proposed that imprinting disorders are a combination of heredity, senescent, COH, ART procedures and culture medium that potentiates the early onset of the diseases .…”

A Molecular Perspective on Procedures and Outcomes with Assisted Reproductive Technologies

“…One study has shown that in some infertile men perturbations in methylation may contribute to abnormal embryo development (Aston et al 2012). The possibility that some aspect(s) of infertility per se contributes to altered phenotype and/or epigenotype is open for consideration and further investigation (Song et al 2015).…”