The artificial uterus: on the way to ectogenesis

The inability to support the growth and development of a mature fetus up to delivery results in significant human suffering. Current available solutions include adoption, surrogacy, and uterus transplantation. However, these options are subject to several ethical, religious, economic, social, and medical concerns. Ectogenesis is the process in which an embryo develops in an artificial uterus from implantation through to the delivery of a live infant. This current narrative review summarizes the state of recent research focused on human ectogenesis. First, a literature search was performed to identify published reports of previous experiments and devices used for embryo implantation in an extracorporeally perfused human uterus. Furthermore, studies fitting that aim were selected and critically evaluated. Results were synthesized, interpreted, and used to design a prospective strategy for future research. Therefore, this study suggests that full ectogenesis might be obtained using a computer-controlled system with extracorporeal blood perfusion provided by a digitally controlled heart-lung-kidney system. From a clinical perspective, patients who will derive significant benefits from this technology are mainly those women diagnosed with anatomical abnormalities of the uterus and those who have undergone previous hysterectomies, numerous abortions, and experienced premature birth. Ectogenesis is the complete development of an embryo in an artificial uterus. It represents the solutions for millions of women suffering from premature deliveries, and the inability to supply growth and development of embryos/fetuses in the womb. In the future, ectogenesis might replace uterine transplantation and surrogacy.

The (Un)Ethical Womb: The Promises and Perils of Artificial Gestation

The purpose of this article is to reflect on the changes that the implementation of artificial wombs would bring to society, the family, and the concept of motherhood and fatherhood through the lens of two recent books: Helen Sedgwick's The Growing Season and Rebecca Ann Smith's Baby X. Each of the two novels, set in a near future, follows the work of a scientist who develops artificial womb technology. Significantly, both women experience concerns about the technology and its long-term effects that make both of them leave their laboratories and rethink the technology they invented, while considering its many ethical implications. Both novels can be seen as feminist revisionary rewritings of Aldous Huxley's Brave New World, rejecting the vision of rows of mass-produced, anonymous babies in artificial wombs, stressing instead the closeness of the parents to their offspring. They nevertheless critically evaluate not only the many potential benefits for women of ectogenetic technology but also the possible disadvantages and pitfalls.

Abortion Rights after Artificial Wombs: Why Decriminalisation is Needed Ahead of Ectogenesis

Significant scientific progress has been made toward artificial womb technology, which would allow part of human gestation to occur outside the body. Bioethical and legal scholars have argued that artificial wombs will challenge defences of abortion based in arguments for protecting bodily autonomy, for a pregnant person could have the foetus transferred to an artificial womb instead of being terminated. Drawing on examples from the common law jurisdictions of Canada, the USA, and the UK, I assess three ways scholars have argued abortion might be defended after ectogenesis (through redefining foetal viability, through a property right, and through a right to avoid genetic parenthood). I argue that while each of these proposals has strategic merit, each has significant legal and ethical limitations. Taking the normative position that abortion will remain a vital healthcare resource, I make the case for protecting abortion rights from a challenge posed by ectogenesis by focusing on decriminalisation.

Why bother the public? A critique of Leslie Cannold's empirical research on ectogenesis

Can discussion with members of the public show philosophers where they have gone wrong? Leslie Cannold argues that it can in her 1995 paper 'Women, Ectogenesis and Ethical Theory', which investigates the ways in which women reason about abortion and ectogenesis (the gestation of foetuses in artificial wombs). In her study, Cannold interviewed female non-philosophers. She divided her participants into separate 'pro-life' and 'pro-choice' groups and asked them to consider whether the availability of ectogenesis would change their views about the morality of dealing with an unwanted pregnancy. The women in Cannold's study gave responses that did not map onto the dominant tropes in the philosophical literature. Yet Cannold did not attempt to reason with her participants, and her engagement with the philosophical literature is oddly limited, focussing only on the pro-choice perspective. In this paper, I explore the question of whether Cannold is correct that philosophers' reasoning about abortion is lacking in some way. I suggest that there are alternative conclusions to be drawn from the data she gathered and that a critical approach is necessary when attempting to undertake philosophy informed by empirical data.

Moving forwards: A problem for full ectogenesis

Most existing literature on the ethics of full ectogenesis has proceeded under the presupposition that science will at some point produce sophisticated technologies for full-term gestation (from embryo to infant) outside the human womb, delivering neonate health outcomes comparable with (or even superior to) biological gestation. However, the development of this technology-as opposed to the support systems currently being advanced-would require human subject experiments in embryo-onwards development using ectogenic prototypes. Literature on ectogenic research ethics has so far focused on 'backwards' development of partial ectogenesis: incubation and ectogestation technologies that would allow the support of earlier and earlier neonates and foetuses. However, little has been said about the ethics of 'forwards' development of (partial or full) ectogenesis, involving the development of embryos and foetuses in prototype environments. Such a prototype might allow us to produce a gestateling or live neonate from a human embryo, but with poorer expected development and health outcomes than from biological gestation; it might also produce only gestatelings (healthy or otherwise) before the technology was developed to a stage where full-term gestation was achievable. This paper explicates some of the ethical issues that this raises for the development of 'full' ectogenesis, and presents prima facie reasons to consider this research problematic and therefore to require extensive further argument in its defence.

Gender, gestation and ectogenesis: self-determination for pregnant people ahead of artificial wombs

In this short response, I agree with Cavaliere's recent invitation to consider ectogenesis, the process of gestation occurring outside the body, as a political perspective and provocation to building a world in which reproductive and care labour are more justly distributed. But I argue that much of the literature Cavaliere addresses in which scholars argue that artificial wombs may produce greater gender equality has the limitation of taking a fixed, binary and biological approach to sex and gender. I argue that in taking steps toward the possibility of more just practices of caregiving and family making, we must look first not to artificial womb technologies but to addressing the ways that contemporary legal and social practices that enforce essentialising, binary ways of thinking about reproductive bodies inhibit this goal.

Ectogenesis and gender-based oppression: Resisting the ideal of assimilation

In a recent article in this journal, Kathryn MacKay advances a defence of ectogenesis that is grounded in this technology's potential to end-or at least mitigate the effects of-gender-based oppression. MacKay raises important issues concerning the socialization of women as 'mothers', and the harms that this socialization causes. She also considers ectogenesis as an ethically preferable alternative to gestational surrogacy and uterine transplantation, one that is less harmful to women and less subject to being co-opted to further oppressive ends. In this article, I challenge some of the assumptions that underlie MacKay's case in favour of ectogenesis by questioning whether the relationship between women's capacity to gestate and birth children and gender-based oppression is as strong as MacKay makes it out to be. I subsequently argue that-even if MacKay's reading of this relationship is accurate-ectogenesis is not a desirable means to end gender-based oppression. It embodies a strategy that could be used to pursue liberating projects that follow what Iris Marion Young defines as 'the ideal of assimilation', but that must be resisted. I then concur with MacKay's contention that ectogenesis is better than gestational surrogacy and uterine transplantation. My argument is that many of the problematic issues that MacKay herself sees as features of these practices will not disappear with ectogenesis. Finally, I conclude that MacKay's narrow focus on women's biology and ectogenesis as a solution to gender-based oppression results in the overlooking of broader systemic issues that contribute to the upholding of oppressive norms.

Artificial wombs, birth and 'birth': a response to Romanis

Recently, I argued that human subjects in artificial wombs (AWs) 'share the same moral status as newborns' and so, deserve the same treatment and protections as newborns. This thesis rests on two claims: (A) subjects of partial ectogenesis-those that develop in utero for at time before being transferred to AWs-are newborns and (B) subjects of complete ectogenesis-those who develop in AWs entirely-share the same moral status as newborns. In response, Elizabeth Chloe Romanis argued that the subject in an AW is 'a unique human entity…rather than a fetus or a newborn'. She provides four lines of response to my essay. First, she argues that I have 'misconstrued' what birth is. Once we correct that error, it becomes clear that subjects of partial ectogenesis have not been born. Second, she argues that my claims imply that non-implanted embryos (existing in vivo) 'would also be "born"'. But that is absurd. Third, she claims I fail to 'meaningfully respond' to distinctions she draws between subjects of ectogenesis and neonates. Finally, she criticises my essay for focusing on subjects of AWs rather than focusing on pregnant persons (who should be at the 'centre' of debates over AWs). I respond to each of these charges. In doing so, I reaffirm that (contra Romanis) some subjects of ectogenesis are newborns and all subjects of ectogenesis-even those that have not been born-share the same moral status as newborns.

Willing mothers: ectogenesis and the role of gestational motherhood

While artificial womb technology (ectogenesis) is currently being studied for the purpose of improving neonatal care, I contend that this technology ought to be pursued as a means to address the unprecedented rate of unintended pregnancies. But ectogenesis, alongside other emerging reproductive technologies, is problematic insofar as it threatens to disrupt the natural link between procreation and parenthood that is normally thought to generate rights and responsibilities for biological parents. I argue that there remains only one potentially viable account of parenthood: the voluntarist account, which construes parental rights as robust moral obligations that must be voluntarily undertaken. The problem is that this account mistakenly presumes a patriarchal divide between procreation and parenthood. I propose a reframing of procreation and parenthood from a feminist perspective that recognises gestational motherhood as involving robust moral obligations that ought to be voluntarily undertaken. If this were the case, all gestational mothers would be, by definition, willing mothers. To make this happen I argue that ectogenesis technology must be a widely available reproductive option.

The 'tyranny of reproduction': Could ectogenesis further women's liberation?

This paper imagines what the liberatory possibilities of (full) ectogenesis are, insofar as it separates woman from female reproductive function. Even before use with human infants, ectogenesis productively disrupts the biological paradigm underlying current gender categories and divisions of labour. I begin by presenting a theory of women's oppression drawn from the radical feminisms of the 1960s, which sees oppression as deeply rooted in biology. On this view, oppressive social meanings are overlaid upon biology and body, as artefacts of culture and history. I then argue that ectogenesis should be pursued to replace two modes of assisted gestation that can be seen as outgrowths of oppressive assumptions about women's function, ectogenesis should be pursued to replace two modes of assisted gestation. These are gestational surrogacy and uterine transplant, which arise partly from gendered, pronatalist, and geneticist norms. These practices are supported by assumptions about women's identity and value. Pursuing technologies such as ectogenesis, which weaken the presumed link between biology and gender, is beneficial to (trans-inclusionary radical) feminist aims, as part of a broad project of challenging dominant power relations resting on and maintaining gender categories. By allowing the conceptual separation of female reproductive function from 'woman', ectogenesis raises questions about how we determine who counts in this gender identity, and also how we value those who claim the identity 'woman'. I conclude that ectogenesis has the potential to challenge traditional patriarchal family structures, and thence all other male-dominated structures (of work, education, cultural production), allowing a reimagining of the family and society in more radical ways than we have yet achieved.

Partial ectogenesis: freedom, equality and political perspective

In this commentary, I consider how Giulia Cavaliere's arguments about the limited reach of the current justifications offered for full ectogenesis in the bioethical literature apply in the context of partial ectogenesis. I suggest that considering the extent to which partial ectogenesis is freedom or equality promoting is more urgent because of the more realistic prospect of artificial womb technology being utilised to facilitate partial gestation extra uterum as opposed to facilitating complete gestation from conception to term. I highlight concerns about potentially harmful social narratives surrounding pregnancy and about the current legal framework surrounding gestation limiting access to technology in the advent of partial ectogenesis. I do not advocate that these concerns mean that we ought not develop artificial wombs, but like Cavaliere I suggest that we must be mindful of these concerns, and I posit that legal reform must accompany technological developments. Ectogenesis as a political perspective, through which we consider the value in social reproduction and the experiences of pregnant people, is useful to prevent political capture of this technology for regressive policies. Using this perspective to examine the law is also a useful tool to expose just how restrictive the law is in relation to gestation and female reproductive health.

Reproductive technologies are not the cure for social problems

Giulia Cavaliere disagrees with claims that ectogenesis will increase equality and freedom for women, arguing that they often ignore social context and consequently fail to recognise that ectogenesis may not benefit women or it may only benefit a small subset of already privileged women. In this commentary, I will contextualise her argument within the broader cultural milieu to highlight the pattern of reproductive advancements and technologies, such as egg freezing and birth control, being presented as the panacea for women's inequality. While these advancements and technologies can benefit women, I argue medicine is not the best tool to 'cure' social problems and should not be co-opted as an agent of social change. Systemic social changes, not just technomedical approaches, are needed to address the root of gender inequality, which is social in nature, not medical.

Gene Editing, Enhancing and Women's Role

A recent article on the front page of The Independent (September 18, 2015) reported that the genetic 'manipulation' of IVF embryos is to start in Britain, using a new revolutionary gene-editing technique, called Crispr/Cas9. About three weeks later (Saturday 10, October 2015), on the front page of the same newspaper, it was reported that the National Health Service (NHS) faces a one billion pound deficit only 3 months into the new year. The hidden connection between these reports is that gene editing could be used to solve issues related to health care allocation. Improving the health of future generations might coincide with public health goals; it might improve the health of individuals and communities, and, if successful, might be seen as a public good. However, enhancing future generations will require In Vitro Fertilisation and Pre-implantation Genetic Diagnosis. Remarkably, the necessary involvement of women in an enhancing scenario has not been discussed by its proponents. The present discourse on moral obligations of future generations, although not referring to women, seems to imply that women might be required, morally, if not legally, to reproduce with IVF. Enhancing future generations will be gendered, unless the artificial womb is developed. These are challenging issues that require a wider perspective, of both women and men. Despite the lack of a unified feminist conclusion in the discussions about the merits and risks of human genome modification, there is an urgent need to clarify the role of women in this scenario.

Ectogenesis and a right to the death of the prenatal human being: A reply to Räsänen

Both many critics of abortion and many defenders of abortion have suggested that artificial wombs could end the abortion debate. If the fetus is removed from the uterus, women have an end to an unwanted pregnancy. If the living fetus is then put in an artificial uterus for ectogenesis, there is no termination of the life of the fetus. Joona Räsänen challenges this view in his article, Ectogenesis, abortion and a right to the death of the fetus. Räsänen provides three arguments for a right to secure the death of the human being in utero, namely the 'right not to become a biological parent argument', the 'right to genetic privacy argument', and the 'right to property argument'. This article critiques these three arguments for a right to the death of the fetus.

Artificial Wombs and Abortion Rights

In a study published in late April in Nature Communications, the authors were able to sustain 105- to 115-day-old premature lamb fetuses-whose level of development was comparable to that of a twenty-three-week-old human fetus-for four weeks in an artificial womb, enabling the lambs to develop in a way that paralleled age-matched controls. The oldest lamb of the set, more than a year old at the time the paper came out, appeared completely normal. This kind of research brings us one step closer to providing excellent quality of life for premature newborns, but it also portends major legal and ethical questions, especially for abortion rights in America.

Toxicity and non-harmful effects of the soya isoflavones, genistein and daidzein, in embryos of the zebrafish, Danio rerio

Based on the assumed oestrogenic and apoptotic properties of soya isoflavones (genistein, daidzein), and following the current OECD test-guidelines and principle of 3Rs, we have studied the potential toxicity of phytochemicals on the zebrafish embryos test (ZFET). For this purpose, zebrafish embryos at 2-3 h post-fertilisation (hpf) were exposed to both soya isoflavones (from 1.25 mg/L to 20 mg/L) and assayed until 96 hpf. Lethal and sub-lethal endpoints (mortality, hatching rates and malformations) were estimated in the ZFET, which was expanded to potential gene expression markers, determining the lowest observed effect (and transcriptional) concentrations (LOEC, LOTEC), and the no-observable effect (and transcriptional) concentrations (NOEC, NOTEC). The results revealed that genistein is more toxic (LC50-96 hpf: 4.41 mg/L) than daidzein (over 65.15 mg/L). Both isoflavones up-regulated the oestrogen (esrrb) and death receptors (fas) and cyp1a transcript levels. Most thyroid transcript signals were up-regulated by genistein (except for thyroid peroxidase/tpo), and the hatching enzyme (he1a1) was exclusively up-regulated by daidzein (from 1.25 mg/L onwards). The ZFET proved suitable for assessing toxicant effects of both isoflavones and potential disruptions (i.e. oestrogenic, apoptotic, thyroid, enzymatic) during the embryogenesis and the endotrophic larval period.

There is no right to the death of the fetus

Joona Räsänen, in his article 'Ectogenesis, abortion and a right to the death of the fetus' (this journal), has argued for the view that parents have a right to the death of the fetus. In this brief article, I will explicate the three arguments Räsänen defends, and show that two of them have false or unmotivated premises and hence fail, and that the support he offers for his third argument is inconsistent with other views he expresses in his article. Therefore, I conclude that there is no right to the death of the fetus, or, if there is one, Räsänen has not shown it.

Clinical analysis of the patients with single fair cleavage-stage embryo on day 3

OBJECTIVE

This study aimed to explore an appropriate selection for the patients with single fair cleavage-stage embryo on day 3.

METHODS

This study included 469 fresh transfers and 220 frozen-thawed transfers from January 2014 to June 2016. Furthermore, in 72 patients who have only 4-6 fair embryos (4-5 blastomeres) on day 3, the blastocysts were cultured to day 5 for transfer.

RESULTS

In the fresh transfers, the clinical pregnancy rate of 4-5 blastomeres group was significantly lower than 6-7 and 8-10 blastomeres group (5.88 vs. 30.13%, p<.001and 5.88 vs. 26.09%, p < .001). In the frozen-thawed transfers, the clinical pregnancy rate of 4-5 blastomeres group was also significantly lower than 6-7 and 8-10 blastomeres group (10.00 vs. 28.57%, p = .040 and 10.00 vs. 33.33%, p = .005). For the blastocyst transfers derived from fair embryos with 4-5 blastomeres, the clinical pregnancy rate was significantly higher than single and double fair embryo transfers of similar quality (44.44 vs. 7.04%, p < .001 and 44.44 vs. 28.09%, p = .013).

CONCLUSIONS

For the patients with single fair embryo (6-7 blastomeres or 8-10 blastomeres), transfer at the cleavage stage is feasible. For the patients with single fair embryo (4-5 blastomeres), transfer of single fair embryo at the blastocyst stage or accumulating two fair embryos might be worthy of consideration.

Ectogenesis, abortion and a right to the death of the fetus

Many people believe that the abortion debate will end when at some point in the future it will be possible for fetuses to develop outside the womb. Ectogenesis, as this technology is called, would make possible to reconcile pro-life and pro-choice positions. That is because it is commonly believed that there is no right to the death of the fetus if it can be detached alive and gestated in an artificial womb. Recently Eric Mathison and Jeremy Davis defended this position, by arguing against three common arguments for a right to the death of the fetus. I claim that their arguments are mistaken. I argue that there is a right to the death of the fetus because gestating a fetus in an artificial womb when genetic parents refuse it violates their rights not to become a biological parent, their rights to genetic privacy and their property rights. The right to the death of the fetus, however, is not a woman's right but genetic parents' collective right which only can be used together.

Heat shock decreases the embryonic quality of frozen-thawed bovine blastocysts produced in vitro

In this study, the effect of heat shock on frozen-thawed blastocysts was evaluated using in vitro-produced (IVP) bovine embryos. In experiment 1, the effects of 6 h of heat shock at 41.0 C on fresh blastocysts were evaluated. HSPA1A expression as a reflection of stress was increased by heat shock (P < 0.05), but the expressions of the quality markers IFNT and POU5F1 were not affected. In experiment 2, frozen-thawed blastocysts were incubated at 38.5 C for 6 h (cryo-con) or exposed to heat shock at 41.0 C for 6 h (cryo-HS). Then, blastocysts were cultured at 38.5 C until 48 h after thawing (both conditions). Cryo-HS blastocysts exhibited a decreased recovery rate: HSPA1A expression was dramatically increased compared with that in fresh or cryo-con blastocysts at 6 h, and IFNT expression was decreased compared with that in cryo-con blastocysts at 6 h (both P < 0.05). Cryo-con blastocysts at 6 h also exhibited higher HSPA1A expression than fresh blastocysts (P < 0.05). At 48 h after thawing, the number of hatched blastocysts and blastocyst diameter were lower in cryo-HS blastocysts (P < 0.05). Cryo-con blastocysts showed lower POU5F1 levels at 48 h than fresh, cryo-con or cryo-HS blastocysts at 6 h (P < 0.05), but their POU5F1 levels were not different from those of cryo-HS blastocysts at 48 h. These results indicated that application of heat shock to frozen-thawed blastocysts was highly damaging. The increase in damage by the interaction of freezing-thawing and heat shock might be one reason for the low conception rate in frozen-thawed embryo transfer in summer.

MicroRNA-34 family expression in bovine gametes and preimplantation embryos

BACKGROUND

Oocyte fertilization and successful embryo implantation are key events marking the onset of pregnancy. In sexually reproducing organisms, embryogenesis begins with the fusion of two haploid gametes, each of which has undergone progressive stages of maturation. In the final stages of oocyte maturation, minimal transcriptional activity is present and regulation of gene expression occurs primarily at the post-transcriptional level. MicroRNAs (miRNA) are potent effectors of post-transcriptional gene silencing and recent evidence demonstrates that the miR-34 family of miRNA are involved in both spermatogenesis and early events of embryogenesis.

METHODS

The profile of miR-34 miRNAs has not been characterized in gametes or embryos of Bos taurus. We therefore used quantitative reverse transcription PCR (qRT-PCR) to examine this family of miRNAs: miR-34a, -34b and -34c as well as their precursors in bovine gametes and in vitro produced embryos. Oocytes were aspirated from antral follicles of bovine ovaries, and sperm cells were isolated from semen samples of 10 bulls with unknown fertility status. Immature and in vitro matured oocytes, as well as cleaved embryos, were collected in pools. Gametes, embryos and ovarian and testis tissues were purified for RNA.

RESULTS

All members of the miR-34 family are present in bovine spermatozoa, while only miR-34a and -34c are present in oocytes and cleaved (2-cell) embryos. Mir-34c demonstrates variation among different bulls and is consistently expressed throughout oocyte maturation and in the embryo. The primary transcript of the miR-34b/c bicistron is abundant in the testes and present in ovarian tissue but undetectable in oocytes and in mature spermatozoa.

CONCLUSIONS

The combination of these findings suggest that miR-34 miRNAs may be required in developing bovine gametes of both sexes, as well as in embryos, and that primary miR-34b/c processing takes place before the completion of gametogenesis. Individual variation in sperm miR-34 family abundance may offer potential as a biomarker of male bovine fertility.

Dynamic regulation of DNA methyltransferases in human oocytes and preimplantation embryos after assisted reproductive technologies

DNA methylation is a key epigenetic modification which is essential for normal embryonic development. Major epigenetic reprogramming takes place during gametogenesis and in the early embryo; the complex DNA methylation patterns are established and maintained by DNA methyltransferases (DNMTs). However, the influence of assisted reproductive technologies (ART) on DNA methylation reprogramming enzymes has predominantly been studied in mice and less so in human oocytes and embryos. The expression and localization patterns of the four known DNMTs were analysed in human oocytes and IVF/ICSI embryos by immunocytochemistry and compared between a reference group of good quality fresh embryos and groups of abnormally developing embryos or embryo groups after cryopreservation. In humans, DNMT1o rather than DNMT1s seems to be the key player for maintaining methylation in early embryos. DNMT3b, rather than DNMT3a and DNMT3L, appears to ensure global DNA remethylation in the blastocysts before implantation. DNMT3L, an important regulator of maternal imprint methylation in mouse, was not detected in human oocytes (GV, MI and MII stage). Our study confirms the existence of species differences for mammalian DNA methylation enzymes. In poor quality fresh embryos, the switch towards nuclear DNMT3b expression was delayed and nuclear DNMT1, DNMT1s and DNMT3b expression was less common. Compared with the reference embryos, a smaller number of cryopreserved embryos showed nuclear DNMT1, while a delayed switch to nuclear DNMT3b and an extended DNMT1s temporal expression pattern were also observed. The spatial and temporal expression patterns of DNMTs seem to be disturbed in abnormally developing embryos and in embryos that have been cryopreserved. Further research must be performed in order to understand whether the potentially disturbed embryonic DNMT expression after cryopreservation has any long-term developmental consequences.

Increased GDF9 and BMP15 mRNA levels in cumulus granulosa cells correlate with oocyte maturation, fertilization, and embryo quality in humans

BACKGROUND

Oocyte secreted factors (OSFs), including growth differentiation factor 9 (GDF9) and bone morphogenetic protein 15 (BMP15), play an important role in the process of follicular development and oocyte maturation. Since OSFs are expressed in oocytes and cumulus granulosa cells, the aim of the present study was to explore whether the expression levels of GDF9 and BMP15 mRNAs in cumulus granulosa cells can be used as molecular markers for predicting oocyte developmental potential.

METHODS

Cumulus cells of 2426 cumulus-oocyte complexes were collected from 196 female patients who underwent intracytoplasmic sperm injection (ICSI) and were used for mRNA detection on the egg retrieval day. Pearson correlation analysis was used to analyze the correlation between OSF expression and general physiological parameters. Partial correlation analysis was used to analyze the correlation between OSF expression and oocyte developmental potential. Covariance analysis was used to compare OSF expression among different groups. Receiver operating characteristic curves were used to examine the diagnostic value of GDF9 and BMP15 mRNA for predicting pregnancy.

RESULTS

The expression levels of GDF9 and BMP15 mRNAs were significantly associated with age, body mass index (BMI), oocyte maturation, normal fertilization, and cleavage rate (P < 0.05). The expression levels of GDF9 and BMP15 mRNAs in the group with high-quality embryos were significantly higher than those in the group without high-quality embryos (P < 0.05). The expression levels of GDF9 and BMP15 mRNAs in the pregnancy group were significantly higher than those in the nonpregnancy group (P < 0.05). The cut-off value of GDF9 mRNA for predicting pregnancy was 4.82, with a sensitivity of 82% and a specificity of 64%. The cut-off value of BMP15 mRNA for predicting pregnancy was 2.60, with a sensitivity of 78% and a specificity of 52%.

CONCLUSIONS

The expression levels of GDF9 and BMP15 mRNAs were closely associated with oocyte maturation, fertilization, embryo quality, and pregnancy outcome; therefore, GDF9 and BMP15 mRNAs in cumulus granulosa cells may be considered as new molecular markers for predicting oocyte developmental potential.

Changes in sex ratio from fertilization to birth in assisted-reproductive-treatment cycles

BACKGROUND

In Western gender-neutral countries, the sex ratio at birth is estimated to be approximately 1.06. This ratio is lower than the estimated sex ratio at fertilization which ranges from 1.07 to 1.70 depending on the figures of sex ratio at birth and differential embryo/fetal mortality rates taken into account to perform these estimations. Likewise, little is known about the sex ratio at implantation in natural and assisted-reproduction-treatment (ART) cycles. In this bioessay, we aim to estimate the sex ratio at fertilization and implantation using data from embryos generated by standard in-vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) in preimplantation genetic diagnosis cycles. Thereafter, we compare sex ratios at implantation and birth in cleavage- and blastocyst-stage-transfer cycles to propose molecular mechanisms accounting for differences in post-implantation male and female mortality and thereby variations in sex ratios at birth in ART cycles.

METHODS

A literature review based on publications up to December 2013 identified by PubMed database searches.

RESULTS

Sex ratio at both fertilization and implantation is estimated to be between 1.29 and 1.50 in IVF cycles and 1.07 in ICSI cycles. Compared with the estimated sex ratio at implantation, sex ratio at birth is lower in IVF cycles (1.03 after cleavage-stage transfer and 1.25 after blastocyst-stage transfer) but similar and close to unity in ICSI cycles (0.95 after cleavage-stage transfer and 1.04 after blastocyst-stage transfer).

CONCLUSIONS

In-vitro-culture-induced precocious X-chromosome inactivation together with ICSI-induced decrease in number of trophectoderm cells in female blastocysts may account for preferential female mortality at early post-implantation stages and thereby variations in sex ratios at birth in ART cycles.

Analysis of embryo morphokinetics, multinucleation and cleavage anomalies using continuous time-lapse monitoring in blastocyst transfer cycles

BACKGROUND

Time-lapse imaging combined with embryo morphokinetics may offer a non-invasive means for improving embryo selection. Data from clinics worldwide are necessary to compare and ultimately develop embryo classifications models using kinetic data. The primary objective of this study was to determine if there were kinetic differences between embryos with limited potential and those more often associated with in vitro blastocyst formation and/or implantation. We also wanted to compare putative kinetic markers for embryo selection as proposed by other laboratories to what we were observing in our own laboratory setting.

METHODS

Kinetic data and cycle outcomes were retrospectively analyzed in patients age 39 and younger with 7 or more zygotes cultured in the Embryoscope. Timing of specific events from the point of insemination were determined using time-lapse (TL) imaging. The following kinetic markers were assessed: time to syngamy (tPNf), t2, time to two cells (c), 3c (t3), 4c ( t4), 5c (t5), 8c (t8), morula (tMor), start of blastulation (tSB); tBL, blastocyst (tBL); expanded blastocyst (tEBL). Durations of the second (cc2) and third (cc3) cell cycles, the t5-t2 interval as well as time to complete synchronous divisions s1, s2 and s3 were calculated. Incidence and impact on development of nuclear and cleavage anomalies were also assessed.

RESULTS

A total of 648 embryos transferred on day 5 were analyzed. The clinical pregnancy and implantation rate were 72% and 50%, respectively. Morphokinetic data showed that tPNf, t2,t4, t8, s1, s2,s3 and cc2 were significantly different in embryos forming blastocysts (ET or frozen) versus those with limited potential either failing to blastulate or else forming poor quality blastocysts ,ultimately discarded. Comparison of embryo kinetics in cycles with all embryos implanting (KID+) versus no implantation (KID-) suggested that markers of embryo competence to implant may be different from ability to form a blastocyst. The incidence of multinucleation and reverse cleavage amongst the embryos observed was 25% and 7%, respectively. Over 40% of embryos exhibiting these characteristics did however form blastocysts meeting our criteria for freezing.

CONCLUSIONS

These data provide us with a platform with which to potentially enhance embryo selection for transfer.

Use of a mouse in vitro fertilization model to understand the developmental origins of health and disease hypothesis

The Developmental Origins of Health and Disease hypothesis holds that alterations to homeostasis during critical periods of development can predispose individuals to adult-onset chronic diseases such as diabetes and metabolic syndrome. It remains controversial whether preimplantation embryo manipulation, clinically used to treat patients with infertility, disturbs homeostasis and affects long-term growth and metabolism. To address this controversy, we have assessed the effects of in vitro fertilization (IVF) on postnatal physiology in mice. We demonstrate that IVF and embryo culture, even under conditions considered optimal for mouse embryo culture, alter postnatal growth trajectory, fat accumulation, and glucose metabolism in adult mice. Unbiased metabolic profiling in serum and microarray analysis of pancreatic islets and insulin sensitive tissues (liver, skeletal muscle, and adipose tissue) revealed broad changes in metabolic homeostasis, characterized by systemic oxidative stress and mitochondrial dysfunction. Adopting a candidate approach, we identify thioredoxin-interacting protein (TXNIP), a key molecule involved in integrating cellular nutritional and oxidative states with metabolic response, as a marker for preimplantation stress and demonstrate tissue-specific epigenetic and transcriptional TXNIP misregulation in selected adult tissues. Importantly, dysregulation of TXNIP expression is associated with enrichment for H4 acetylation at the Txnip promoter that persists from the blastocyst stage through adulthood in adipose tissue. Our data support the vulnerability of preimplantation embryos to environmental disturbance and demonstrate that conception by IVF can reprogram metabolic homeostasis through metabolic, transcriptional, and epigenetic mechanisms with lasting effects for adult growth and fitness. This study has wide clinical relevance and underscores the importance of continued follow-up of IVF-conceived offspring.

Cryopreservation of day 2-3 embryos by vitrification yields better outcome than slow freezing

OBJECTIVE

To compare the outcome of vitrification versus slow freezing cryopreservation for cleavage stage day 2-3 embryos.

DESIGN

A retrospective observational study.

SETTING

All thawed embryos assisted reproduction cycles between January 2010 and December 2012 at a single IVF laboratory of a Tertiary Medical Center.

PATIENTS

Five hundred and thirty-nine cycles of day 2-3 thawed embryos.

INTERVENTIONS

In 327 of the thawed cycles, the embryos were vitrified and in 212 of the cycles the embryos were derived from slow freezing embryos.

MAIN OUTCOMES MEASURE

Embryo survival rate, blastomere surviving rate and pregnancy rate.

RESULTS

Embryo survival rate was significantly higher after vitrification compared with slow freezing (81.6%, 647/793 versus 70.0%, 393/562 embryos, p < 0.0001). The clinical pregnancy rate per ET was significantly higher following vitrification compared to slow freezing, 20.0%, 63/314 versus 11.9%, 23/193, respectively (p = 0.02).

CONCLUSIONS

Vitrification of day 2-3 cleavage stage embryos yields better cycle outcome in all the parameters compared to slow freezing.

[Application of human oocyte morphometric parameters in assessment of fertilization and embryo development]

OBJECTIVE

To investigate the correlation of human oocyte morphometric parameters with fertilization and embryo development in the intracytoplasmic sperm injection (ICSI) cycles.

METHODS

The morphometric parameters of oocytes collected and submitted to evaluation using OCTAX Eye-ware software just before ICSI. Oocyte diameter (OD), perivitelline space width (PSW), zonapellucida thickness (ZPT) and the shape of first polar body (FPB) (intact or fragmented) were analyzed. A stepwise multivariate Logistic regression was used to test the association between the morphometric parameters and fertilization and embryo development.

RESULTS

In the study, 436 oocytes were measured and 370 were fertilized (84.9%), 225 fertilized oocytes were developed to high-quality embryos (60.8%). ZPT and PSW were associated with fertilization. The oocytes fertilized had thicker ZPT [(18.0±2.3) μm vs. (16.9±2.7) μm] and wider PSW [(14.4±3.3) μm vs. (13.2±3.9) μm]. The OD and shape of FPB were associated with embryos development. The oocytes developed to high-quality embryos had larger OD [(116.6±3.7) μm vs. (114.7±3.6) μm] and more intact FPB (86.2% vs. 66.7%).

CONCLUSION

The morphometric parameters of oocytes can indicate fertilization and embryo development.

Expression and putative function of kisspeptins and their receptors during early development in medaka

Kisspeptins (Kiss1 and Kiss2) and their receptors (putatively Gpr54-1 and Gpr54-2) have emerged as key players in vertebrate reproduction owing to their stimulatory effect on the brain-pituitary-gonadal axis. Virtually nothing is known, however, about their role during embryogenesis. Using medaka (Teleostei) as a model system, we report, for the first time in vertebrates, an early developmental expression and putative function of kisspeptins. Expression analyses and knockdown experiments suggest that early actions of kisspeptins are probably mediated by binding to maternally supplied Gpr54-1 and late action by both Gpr54-1 and Gpr54-2. Knockdown of maternally provided kiss1 and gpr54-1 arrested development during gastrulation, before establishment of any germ layers, whereas knockdown of zygotically provided kiss1 and gpr54-1 disrupted brain development. A similar phenotype was observed for gpr54-2 knockdown embryos, suggesting a critical role for kiss1, gpr54-1, and gpr54-2 in neurulation. These data demonstrate that kisspeptin signaling is active both maternally and zygotically and is involved in embryonic survival and morphogenesis.

Yolk formation in a stony coral Euphyllia ancora (Cnidaria, Anthozoa): insight into the evolution of vitellogenesis in nonbilaterian animals

Vitellogenin (Vg) is a major yolk protein precursor in numerous oviparous animals. Numerous studies in bilateral oviparous animals have shown that Vg sequences are conserved across taxa and that Vgs are synthesized by somatic-cell lineages, transported to and accumulated in oocytes, and eventually used for supporting embryogenesis. In nonbilateral animals (Polifera, Cnidaria, and Ctenophora), which are regarded as evolutionarily primitive, although Vg cDNA has been identified in 2 coral species from Cnidaria, relatively little is known about the characteristics of yolk formation in their bodies. To address this issue, we identified and characterized 2 cDNA encoding yolk proteins, Vg and egg protein (Ep), in the stony coral Euphyllia ancora. RT-PCR analysis revealed that expression levels of both Vg and Ep increased in the female colonies as coral approached the spawning season. In addition, high levels of both Vg and Ep transcripts were detected in the putative ovarian tissue, as determined by tissue distribution analysis. Further analyses using mRNA in situ hybridization and immunohistochemistry determined that, within the putative ovarian tissue, these yolk proteins are synthesized in the mesenterial somatic cells but not in oocytes themselves. Furthermore, Vg proteins that accumulated in eggs were most likely consumed during the coral embryonic development, as assessed by immunoblotting. The characteristics of Vg that we identified in corals were somewhat similar to those of Vg in bilaterian oviparous animals, raising the hypothesis that such characteristics were likely present in the oogenesis of some common ancestor prior to divergence of the cnidarian and bilaterian lineages.

More than just a matter of time

A response to the editorial "On patenting time and other natural phenomenon" by Jacques Cohen.

Legal aspects of patenting time

Times of embryonic development are naturally occurring phenomena and, therefore, under the caveat that all things in nature without human intervention are not patentable, should not be patentable.

Absence of cumulus cells during in vitro maturation affects lipid metabolism in bovine oocytes

Cumulus cells (CC) surround the oocyte and are coupled metabolically through regulation of nutrient intake. CC removal before in vitro maturation (IVM) decreases bovine oocyte developmental competence without affecting nuclear meiotic maturation. The objective was to investigate the influence of CC on oocyte cytoplasmic maturation in relation to energy metabolism. IVM with either cumulus-enclosed (CEO) or -denuded (DO) oocytes was performed in serum-free metabolically optimized medium. Transmission electron microscopy revealed different distribution of membrane-bound vesicles and lipid droplets between metaphase II DO and CEO. By Nile Red staining, a significant reduction in total lipid level was evidenced in DO. Global transcriptomic analysis revealed differential expression of genes regulating energy metabolism, transcription, and translation between CEO and DO. By Western blot, fatty acid synthase (FAS) and hormone-sensitive phospholipase (HSL) proteins were detected in oocytes and in CC, indicating a local lipogenesis and lypolysis. FAS protein was significantly less abundant in DO that in CEO and more highly expressed in CC than in the oocytes. On the contrary, HSL protein was more abundant in oocytes than in CC. In addition, active Ser⁵⁶³-phosphorylated HSL was detected in the oocytes only after IVM, and its level was similar in CEO and DO. In conclusion, absence of CC during IVM affected lipid metabolism in the oocyte and led to suboptimal cytoplasmic maturation. Thus, CC may influence the oocyte by orienting the consumption of nutritive storage via regulation of local fatty acid synthesis and lipolysis to provide energy for maturation.

Is there a link between blastomere contact surfaces of day 3 embryos and live birth rate?

BACKGROUND

Cell-cell communication and adhesion are essential for the compaction process of early stage embryos. The aim of this study was to develop a non-invasive objective calculation system of embryo compaction in order to test the hypothesis that embryos with a larger mean contact surface result in a higher live birth rate compared to embryos with a lower mean contact surface.

METHODS

Multilevel images of 474 embryos transferred on day 3 were evaluated by the Cellify software. This software calculates the contact surfaces between the blastomeres. The primary outcome of this study was live birth. An ideal range of contact surface was determined and the positive and negative predictive value, the sensitivity, the specificity and the area under the curve for this new characteristic were calculated.

RESULTS

In total, 115 (24%) transferred embryos resulted in a live birth. Selection of an embryo for transfer on its mean contact surface could predict live birth with a high sensitivity (80%) and high negative predicting value (83%) but with a low positive predictive value (27%), a low specificity (31%) and low area under the ROC curve (0.56). The mean contact surface of embryos cultured in a single medium was significantly higher compared to the mean contact surface of embryos cultured in a sequential medium (p = 0.0003).

CONCLUSIONS

Neither the mean contact surface nor the number of contact surfaces of a day 3 embryo had an additional value in the prediction of live birth. The type of culture medium, however, had an impact on the contact surface of an embryo. Embryos cultured in a single medium had a significant larger contact surface compared to embryos cultured in the sequential medium.

Evaluation of developmental changes in bovine in vitro produced embryos following exposure to bovine Herpesvirus type 5

BACKGROUND

Bovine Herpesvirus type-5 (BoHV-5) is a neurovirulent α-Herpesvirus which is potentially pathogenic for cows and suspected to be associated with reproductive disorders. Interestingly, natural transmission of BoHV-5 by contaminated semen was recently described in Australia. Additionally, BoHV-5 was also isolated from the semen of a healthy bull in the same country and incriminated in a natural outbreak of reproductive disease after artificial insemination. In contrast with BoHV-1, experimental exposure of in vitro produced bovine embryos to BoHV-5 does not affect embryo viability and seems to inhibit some pathways of apoptosis. However, the mechanisms responsible for these phenomena are poorly understood. In this study, we examined mitochondrial activity, antioxidant protection, stress response and developmental rates of in vitro produced bovine embryos that were exposed and unexposed to BoHV-5.

METHODS

For this purpose, bovine embryos produced in vitro were assayed for cell markers after experimental infection of oocytes (n = 30; five repetitions), in vitro fertilization and development. The indirect immunofluorescence was employed to measure the expression of superoxide dismutase 1 (SOD1), anti-oxidant like protein 1 (AOP-1), heat shock protein 70.1 (Hsp 70.1) and also viral antigens in embryos derived from BoHV-5 exposed and unexposed oocytes. The determination of gene transcripts of mitochondrial activity (SOD1), antioxidant protection (AOP-1) and stress response (Hsp70.1) were evaluated using the reverse transcriptase polymerase chain reaction (RT-PCR). MitoTracker Green FM, JC-1 and Hoechst 33342-staining were used to evaluate mitochondrial distribution, segregation patterns and embryos morphology. The intensity of labeling was graded semi-quantitatively and embryos considered intensively marked were used for statistical analysis.

RESULTS

The quality of the produced embryos was not affected by exposure to BoHV-5. Of the 357 collected oocytes, 313 (+/- 6.5; 87.7%) were cleaved and 195 (+/- 3.2; 54.6%) blastocysts were produced without virus exposure. After exposure, 388 oocytes were cleaved into 328 (+/- 8.9, 84.5%), and these embryos produced 193 (+/- 3.2, 49.7%) blastocysts. Viral DNA corresponding to the US9 gene was only detected in embryos at day 7 after in vitro culture, and confirmed by indirect immunofluorescence assay (IFA). These results revealed significant differences (p < 0.05) between exposed and unexposed oocytes fertilized, as MitoTracker Green FM staining Fluorescence intensity of Jc-1 staining was significantly higher (p < 0.005) among exposed embryos (143 +/- 8.2). There was no significant difference between the ratios of Hoechst 33342-stained nuclei and total cells in good-quality blastocysts (in both the exposed and unexposed groups). Using IFA and reverse transcriptase polymerase chain reaction (RT-PCR) for the set of target transcripts (SOD1, AOP-1 and Hsp 70.1), there were differences in the mRNA and respective proteins between the control and exposed embryos. Only the exposed embryos produced anti-oxidant protein-like 1 (AOP-1). However, neither the control nor the exposed embryos produced the heat shock protein Hsp 70.1. Interestingly, both the control and the exposed embryos produced superoxide dismutase (SOD1), revealing intense mitochondrial activity.

CONCLUSION

This is the first demonstration of SOD1 and AOP-1 production in bovine embryos exposed to BoHV-5. Intense mitochondrial activity was also observed during infection, and this occurred without interfering with the quality or number of produced embryos. These findings further our understanding on the ability of α-Herpesviruses to prevent apoptosis by modulating mitochondrial pathways.

Seasonal variability in the fertilization rate of women undergoing assisted reproduction treatments

The objective of this study was to evaluate whether seasonality affects human-assisted reproduction treatment outcomes. For this, 1932 patients undergoing intracytoplasmic sperm injection (ICSI) were assigned to a season group according to the day of oocyte retrieval: winter (n = 435), spring (n = 444), summer (n = 469) or autumn (n = 584). Analysis of variance was used to compare the ICSI outcomes. The fertilization rate was increased during the spring (winter: 67.9%, spring: 73.5%, summer: 68.7% and autumn: 69.0%; p < 0.01). In fact, a nearly 50% increase in the fertilization rate during the spring was observed (odds ratio 1.45, confidence interval 1.20-1.75; p < 0.01). The oestradiol concentration per number of oocytes was significantly higher during the spring (winter: 235.8 pg/mL, spring: 282.1 pg/mL, summer: 226.1 pg/mL and autumn: 228.7 pg/mL; p = 0.030). This study demonstrates a seasonal variability in fertilization after ICSI, where fertilization is higher during the spring than at any other time.

Hollow fiber vitrification provides a novel method for cryopreserving in vitro maturation/fertilization-derived porcine embryos

In vitro matured (IVM) oocytes have been used to create genetically modified pigs for various biomedical purposes. However, porcine embryos derived from IVM oocytes are very cryosensitive. Developing improved cryopreservation methods would facilitate the production of genetically modified pigs and also accelerate the conservation of genetic resources. We recently developed a novel hollow fiber vitrification (HFV) method; the present study was initiated to determine whether this new method permits the cryopreservation of IVM oocyte-derived porcine embryos. Embryos were created from the in vitro fertilization of IVM oocytes with frozen-thawed sperm derived from a transgenic pig carrying a humanized Kusabira-Orange (huKO) gene. Morula-stage embryos were assigned to vitrification and nonvitrification groups to compare their in vitro and in vivo developmental abilities. Vitrified morulae developed to the blastocyst stage at a rate similar to that of nonvitrified embryos (66/85, 77.6% vs. 67/84, 79.8%). Eighty-eight blastocysts that developed from vitrified morulae were transferred into the uteri of three recipient gilts. All three became pregnant and produced a total of 17 piglets (19.3%). This piglet production was slightly lower, albeit not significantly, than that of the nonvitrification group (27/88, 30.7%). Approximately half of the piglets in the vitrification (10/17, 58.8%) and nonvitrification (15/27, 55.6%) groups were transgenic. There was no significant difference in the growth rates among the piglets in the two groups. These results indicate that the HFV method is an extremely effective method for preserving cryosensitive embryos such as porcine in vitro maturation/fertilization-derived morulae.

The relationship between meiotic spindle imaging and outcome of intracytoplasmic sperm injection: a retrospective study

Meiotic spindle analysis with a non-invasive technique, the PolScope, is used to protect the meiotic spindle from damage during microinjection. To evaluate the predictive feature of PolScope, we have designed a retrospective study to analyse the correlation between the meiotic spindle visualisation with regard to spindle location and outcomes of assisted reproductive technologies (ART), including patient age, previous cycles, the number of the collected oocytes, fertilisation rates (FR), pronuclear scoring (PNS) and embryo scoring of the days from two to five. All of the data belonging to 1496 oocytes from 190 patients were statistically analysed. We found that the oocytes having PolScope visualised spindle have higher FR, and also observed that when the spindle located at 0°-30° according to the first polar body, gave the highest FR. PNS gave higher scores in the spindle visualised group, but spindle angle did not affect PNS outcomes. Although a correlation was found between spindle visualisation and developed embryo qualities, particularly at day 2 and 3, spindle angles did not affect embryo quality. We conclude that PolScope microscopy has an efficiency to estimate FR, and cleavage stage embryo development.

Is pronuclear scoring a really good predictor for ICSI cycles?

BACKGROUND/AIMS

Since the assessments of the morphology of oocytes, zygotes and/or embryos are of crucial importance to select the best candidate for pregnancy, many morphological evaluation tools have been proposed. Although embryo scoring, particularly cleavage and blastocyst stages, is more convincing due to successful results, zygote scoring still have a bias as different outcomes. In the current study, we designed a prospective study to test the reliability of zygote scoring by focusing on zygote evaluation techniques and its relation with embryo development and embryo selection for transfer.

METHODS

A total of 1215 mature oocytes from 139 couples were evaluated for the study.

RESULTS

There is no correlation between published zygote scoring technique and embryo development.

CONCLUSIONS

We conclude that the inconsistency of data obtained from zygote scoring might be caused by the static nature of pronuclear stage embryos and thus pronuclear scoring seems to be unreliable evaluation technique for embryo selection.

Improved blastocyst development of single cow OPU-derived presumptive zygotes by group culture with agarose-embedded helper embryos

BACKGROUND

The in vitro culture of presumed zygotes derived from single cow ovum pick-up (OPU) is important for the production of quality blastocysts maintaining pedigree. The aim of the present study was to evaluate the agar chip-embedded helper embryo coculture system for single cow OPU-derived zygotes by assessing embryo quality.

METHODS

Cumulus oocyte complexes (COCs) were collected from Hanwoo cows with high genetic merit twice a week using the ultra-sound guided OPU technique and from slaughterhouse ovaries. The Hanwoo cow COCs and slaughterhouse ovaries were matured in vitro, fertilized in vitro with thawed Hanwoo sperm and cultured for 24 h. The presumed zygotes were subsequently placed in three different culture systems: (1) control OPU (controlOPU) with single cow OPU-derived presumed zygotes (2~8); (2) agar chip-embedded slaughterhouse helper embryo coculture (agarOPU) with ten presumed zygotes including all presumed zygotes from a cow (2~8) and the rest from agar chip-embedded slaughterhouse presumed zygotes (8~2); and (3) slaughterhouse in vitro embryo production (sIVP) with ten slaughterhouse ovary-derived presumed zygotes, each in 50 μL droplets. Day 8 blastocysts were assayed for apoptosis and gene expression using real time PCR.

RESULTS

The coculture system promoted higher blastocyst development in OPU zygotes compared to control OPU zygotes cultured alone (35.2 vs. 13.9%; P < 0.01). Genes predicted to be involved in implantation failure and/or embryo resorption were down-regulated (P < 0.05) in control OPU zygotes (CD9, 0.4-fold; AKRAB1, 0.3-fold) and in cocultured zygotes (CD9, 0.3-fold; AKRAB1, 0.3-fold) compared to sIVP blastocysts (1.0-fold). Moreover, genes involved in implantation and/or normal calf delivery were up-regulated (P < 0.05 to P < 0.01) in control OPU zygotes (PGSH2, 5.0-fold; TXN, 4.3-fold; PLAU, 1.7-fold) and cocultured zygotes (PGSH2, 14.5-fold; TXN, 3.2-fold; PLAU, 6.8-fold) compared to sIVP (1.0-fold) blastocysts. However, the expression of PLAC8, TGF-β1, ODC1, ATP5A1 and CASP3 did not differ between the three culture groups.

CONCLUSIONS

Results show that the agar chip-embedded helper embryo coculture system enhances developmental competence and embryo quality in cultures of limited numbers of high pedigree single cow OPU presumed zygotes.

Lack of maternal glutamate cysteine ligase modifier subunit (Gclm) decreases oocyte glutathione concentrations and disrupts preimplantation development in mice

Glutathione (GSH) is the most abundant intracellular thiol and an important regulator of cellular redox status. Mice that lack the modifier subunit of glutamate cysteine ligase (Gclm), the rate-limiting enzyme in GSH synthesis, have decreased GSH synthesis. Nicotinamide nucleotide transhydrogenase, an inner mitochondrial membrane protein, catalyzes the interconversion of reduced nicotinamide adenine dinucleotide and reduced nicotinamide adenine dinucleotide phosphate; reduced nicotinamide adenine dinucleotide phosphate is required for reduction of GSH disulfide. Previous work supports roles for GSH in preimplantation development. We hypothesized that Gclm-/- mice have increased preimplantation embryonic mortality and that this effect is enhanced by absence of a functioning Nnt gene. Gclm-/- females produced significantly fewer pups per litter than Gclm+/+ littermates. Numbers of oocytes ovulated in a natural estrous cycle or upon superovulation did not differ by genotype. Fewer uterine implantation sites were observed in the Gclm-/- females. Prepubertal Gclm-/- and Gclm+/+ females were superovulated, then mated overnight with a Gclm+/+ male. At 0.5 d postcoitum, Gclm-/- females had significantly lower percentages of zygotes with two pronuclei and higher percentages of zygotes with one pronucleus than Gclm+/+ or Gclm+/- females. At 3.5 d postcoitum, a significantly lower percentage of blastocyst stage embryos was recovered from uteri of Gclm-/- females than Gclm+/+ females. Embryonic development to the blastocyst stage, but not the two-cell stage, was significantly decreased after in vitro fertilization of oocytes from Gclm-/- females compared with Gclm+/+ females. The Nnt mutation did not enhance the effects of Gclm genotype on female fertility. These results demonstrate critical roles for maternal GSH in supporting normal preimplantation development.

Artificial reproduction technologies (RTs) - all the way to the artificial womb?

In this paper, I argue that the development of an artificial womb is already well on its way. By putting together pieces of information arising from new scientific advances in different areas, (neo-natal care, gynecology, embryology, the human genome project and computer science), I delineate a distinctive picture, which clearly suggests that the artificial womb may become a reality sooner than we may think. Currently, there is a huge gap between the first stages of gestation (using in vitro fertilization) and the 22nd week (inside the womb). At the present time this gap seems an insurmountable barrier for fully developing a fetus outside a natural womb - a notion better known as ectogenesis. The history of science however, suggests that impenetrable barriers are such only temporarily. It is just a matter of time (and due research) until someone - intentionally or by chance - accesses the right answer and finds a way to overcome existing obstacles. Despite misgivings that the case of the artificial womb presents too many barriers, it would be naive to suppose things would happen any differently. I observe in this paper, that it is time to acknowledge the consequences of new developments in different areas of scientific research which are leading to the advent of an artificial womb; and I modestly suggest that we might initiate a discussion on this topic now, while we have still enough time to decide what we may want and why.