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

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.

Cloning and analysis of IFRG (interferon responsive gene) in rabbit oocytes and preimplantation embryos

Although there is more evidence that shows that IFNs (interferons) plays a very important role in the early development of the embryo, the mechanism of IFNs is still unclear. Our study showed that IFRG is expressed from oocytes- through to the preimplantation embryo in rabbits. This finding provides some clues for better understanding the role of IFNs in the development of the embryo. The full length of rabbit IFRG cDNA (Accession No. AJ584672), with a 2794bp encoding 131 amino acid sequence, was cloned IFRG expression can be detected in 8 different tissues: ovary, heart, lung, liver, kidney, spleen, cerebra, and the 18-day whole-body embryo. Whole-mount in situ hybridization showed that IFRG was highly expressed in the inner-cell mass of rabbit blastula. IFRG may play an important role in embryo development and tissue differentiation.

Genes envolvidos no controle do desenvolvimento inicial do rim / Genes involved in the control of early kidney development

As doenças renais humanas são uns dos maiores problemas de saúde, e vários genes quecontrolam a nefrogênese estão associados com essas doenças. Os principais genes envolvidosno desenvolvimento inicial do rim são PAX2, EYA1, SIX1 E 2, SALL1, FOXC1, WT1, HOX11, e amaioria dos fatores transcricionais desses genes é importante na regulação do gene GDNF. Essesgenes interagem uns com os outros, formando uma espécie de rede genética. O estudo dessasinterações genéticas é essencial para o entendimento das bases moleculares das malformaçõesdo desenvolvimento renal, que é necessário para a prevenção e tratamento dessas desordens.

Renal human diseases are among the leading health problems and many genes that controlnephrogenesis are associated with these diseases. The main genes involved in early kidneydevelopment are PAX2, EYA1, SIX1 and 2, SALL1, FOXC1, WT1, HOX11, and the majority oftheir transcriptional factors are relevant to the regulation of GDNF. Those genes interact with oneanother to create a genetic network. The study of such genetic interactions is crucial forunderstanding the molecular basis of kidney development malformations, which is necessary forthe prevention and treatment of these disorders.