In vitro fertilization (IVF) in mammals: epigenetic and developmental alterations. Scientific and bioethical implications for IVF in humans.

Patricio Ventura-Juncá,Juan I Gutiérrez,Augusto J Rolle,Manuel J Santos,Isabel Irarrázaval,Ricardo D Moreno

doi:10.1186/s40659-015-0059-y

Patricio Ventura-Juncá, Juan I Gutiérrez + Show 4 more

Open Access

https://doi.org/10.1186/s40659-015-0059-y

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Abstract

The advent of in vitro fertilization (IVF) in animals and humans implies an extraordinary change in the environment where the beginning of a new organism takes place. In mammals fertilization occurs in the maternal oviduct, where there are unique conditions for guaranteeing the encounter of the gametes and the first stages of development of the embryo and thus its future. During this period a major epigenetic reprogramming takes place that is crucial for the normal fate of the embryo. This epigenetic reprogramming is very vulnerable to changes in environmental conditions such as the ones implied in IVF, including in vitro culture, nutrition, light, temperature, oxygen tension, embryo-maternal signaling, and the general absence of protection against foreign elements that could affect the stability of this process. The objective of this review is to update the impact of the various conditions inherent in the use of IVF on the epigenetic profile and outcomes of mammalian embryos, including superovulation, IVF technique, embryo culture and manipulation and absence of embryo-maternal signaling. It also covers the possible transgenerational inheritance of the epigenetic alterations associated with assisted reproductive technologies (ART), including its phenotypic consequences as is in the case of the large offspring syndrome (LOS). Finally, the important scientific and bioethical implications of the results found in animals are discussed in terms of the ART in humans.

Highlights

Human beings have the capacity to modify the environment and in this way to influence the development and survival of animal species and human beings
The aim of this review is to update the currently available information provided by animal studies exploring offspring alterations in the epigenetic profile, development, survival and phenotype associated with the artificial environment in which in vitro fertilization (IVF) is performed. We propose that this information has scientific and bioethical implications that must be considered in human IVF/Intra‐cytoplasmatic sperm injection (ICSI)
The results show that when germinal vesicle oocyte after in vitro maturation (IVM) are compared to those isolated from mice ovary, a loss of methylation at the Igf2R locus and Mest/Peg1 locus, and a gain of methylation at the H19 locus were found

Summary

Introduction

Human beings have the capacity to modify the environment and in this way to influence the development and survival of animal species and human beings. A more precise definition is: “The study of changes in gene function that are mitotically and/or meiotically heritable and that do not entail a change in DNA sequence” [18] This concept has broadened biological research in order to understand how this process can be altered by the environment and influence normal development and impact the etiology, susceptibility and onset of adult diseases [19,20,21,22,23,24]. There is an important epigenetic reprogramming during gametogenesis and the preimplantational period of the embryo, especially in imprinted genes, defined by their parental origin [25, 26] This period has a sensible window to environmental changes which can alter the process of reprogramming, and thereby affect survival and the early and late development of mammal embryos [27, 28].

Fertilization technique

Discussion