Female tract cytokines and developmental programming in embryos

Exposure to urban ambient particles (PM2.5) before pregnancy affects the expression of endometrial receptive markers to embryo implantation in mice: Preliminary results

Air pollution (AP) is one of the main recent concerns in reproductive healthy due to its potential to promote negative outcomes during pregnancy and male and female fertility. Several studies have demonstrated that AP exposure has been linked to increased embryonic implantation failures, alterations in embryonic, fetal and placental development. For a well-succeeded implantation, both competent blastocyst and receptive endometrium are required. Based on the lack of data about the effect of AP in endometrial receptivity, this study aimed to evaluate he particulate matter (PM) exposure impact on uterine receptive markers in mice and associate the alterations to increased implantation failures due to AP. For this study, ten dams per group were exposed for 39 days to either filter (F) or polluted air (CAP). At fourth gestational day (GD4), females were euthanized. Morphological, ultrastructural, immunohistochemical and molecular analysis of uterine and ovarian samples were performed. CAP-exposed females presented a reduced number of corpus luteum; glands and epithelial cells were increased with pinopodes formation impairment. Immunohistochemistry analysis revealed decreased LIF protein levels. These preliminary data suggests that PM exposure may exert negative effects on endometrial receptivity by affecting crucial parameters to embryonic implantation as uterine morphological differentiation, corpus luteum quantity and LIF expression during implantation window.

Investigating the molecular mechanism of traditional Chinese medicine for the treatment of placental syndromes by influencing inflammatory cytokines using the Mendelian randomization and molecular docking technology

Introduction

Placental syndromes, which include pregnancy loss, preterm birth, gestational diabetes mellitus (GDM), and hypertensive disorders in pregnancy (HDP), have a strong association with disorder inflammatory reactions. Nonetheless, the exact causal relationship has not been established. This study aims to investigate the causal relationship between placental syndromes and inflammatory cytokines utilizing Mendelian randomization (MR). Additionally, we examined the interaction between small molecular compounds derived from traditional Chinese medicine and inflammatory cytokines using molecular docking method.

Methods

After obtaining the data of inflammatory cytokines and placental syndromes, as well as establishing single nucleotide polymorphisms (SNPs), we employed the inverse variance weighted (IVW) method to assess the causal relationship. We also accessed the heterogeneity and the horizontal pleiotropy of these data. The "ClusterProfiler" R package was utilized for Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) term analyses. The protein-protein interaction (PPI) network was constructed using STRING database. AutoDock Vina software was used for molecular docking, and Discovery Studio 2019 was used for visualization purposes.

Results

We found that the growth regulated oncogene A (GROA) and interleukin-9 (IL-9) were associated with the development of pregnancy hypertension, whereas interleukin-10 (IL-10) and hepatocyte growth factor (HGF) were linked to the occurrence of preeclampsia. Moreover, there were correlations observed between interleukin-18 (IL-18), IL-10, macrophage colony-stimulating factor (MCSF), and platelet-derived growth factor BB (PDGFbb) in cases of chronic hypertension combined with pregnancy (CHP). Additionally, macrophage migration inhibitory factor (MIF) exhibited a connection with GDM, and TNF related apoptosis inducing ligand (TRAIL) demonstrated a causal relationship with preterm birth. It is plausible to suggest that interleukin-1β (IL-1β) might contribute to the promotion of pregnancy loss. All of the binding free energy values of small molecular compounds with inflammatory cytokines were below -5.0 kcal/mol. Furthermore, all of the RMSD values were less than 2.

Conclusions

GROA, IL-1β, IL-9, IL-10, IL-18, MIF, MCSF, HGF, PDGFbb and TRAIL were found to be causally associated with placental syndromes. Molecular docking analysis revealed that small molecular compounds, such as puerarin, magnolol, atractylenolide I, paeoniflorin, tumulosic acid and wogonin, are closely bound to these inflammatory cytokines.

Immune–Metabolic Interactions and T Cell Tolerance in Pregnancy

Pregnancy depends on a state of maternal immune tolerance mediated by CD4+ regulatory T (Treg) cells. Uterine Treg cells release anti-inflammatory factors, inhibit effector immunity, and support adaptation of the uterine vasculature to facilitate placental development. Insufficient Treg cells or inadequate functional competence is implicated in infertility and recurrent miscarriage, as well as pregnancy complications preeclampsia, fetal growth restriction, and preterm birth, which stem from placental insufficiency. In this review we address an emerging area of interest in pregnancy immunology–the significance of metabolic status in regulating the Treg cell expansion required for maternal–fetal tolerance. We describe how hyperglycemia and insulin resistance affect T cell responses to suppress generation of Treg cells, summarize data that implicate a role for altered glucose metabolism in impaired maternal–fetal tolerance, and explore the prospect of targeting dysregulated metabolism to rebalance the adaptive immune response in women experiencing reproductive disorders.

Composition and effects of seminal plasma in the female reproductive tracts on implantation of human embryos

The function of seminal plasma involves acting as a transport medium for sperm and as a means of communication between the reproductive tissues of the male and female. It is also a vital factor to prime the reproductive tracts of the female for optimal pregnancy. When the reproductive tract of the female is exposed to seminal plasma, serious alterations take place, enhancing pathogen and debris clearance observed in the uterus throughout mating. It is also capable of supporting embryo growth, promoting the receptivity of the uterus, and establishing tolerance to the semi-allogenic embryo. Moreover, seminal plasma is capable of regulating the functions of several female reproductive organs and providing an ideal condition for effective embryo implantation and pregnancy. It is believed that the health state of the offspring is affected by exposure to seminal plasma. For the treatment of infertility, assisted reproductive technologies have been extensively employed. The application of seminal plasma as a therapeutic approach to enhance the development of embryo competency and rate of implantation, receptivity of endometrium, and establishment of maternal immune tolerance in cycles of ART appears possible. Herein, current knowledge on the composition of seminal plasma and the physiological roles it possesses on various parts of the female reproductive tract are summarized. Moreover, the role of seminal plasma in the development of embryos, implantation, and the following fetal growth and survival have been reviewed in this article.

Toll-like receptor-4 null mutation causes fetal loss and fetal growth restriction associated with impaired maternal immune tolerance in mice

Maternal immune adaptation to accommodate pregnancy depends on sufficient availability of regulatory T (Treg) cells to enable embryo implantation. Toll-like receptor 4 is implicated as a key upstream driver of a controlled inflammatory response, elicited by signals in male partner seminal fluid, to initiate expansion of the maternal Treg cell pool after mating. Here, we report that mice with null mutation in Tlr4 (Tlr4^−/−) exhibit impaired reproductive outcomes after allogeneic mating, with reduced pregnancy rate, elevated mid-gestation fetal loss, and fetal growth restriction, compared to Tlr4^+/+ wild-type controls. To investigate the effects of TLR4 deficiency on early events of maternal immune adaptation, TLR4-regulated cytokines and immune regulatory microRNAs were measured in the uterus at 8 h post-mating by qPCR, and Treg cells in uterus-draining lymph nodes were evaluated by flow cytometry on day 3.5 post-coitum. Ptgs2 encoding prostaglandin-endoperoxide synthase 2, cytokines Csf2, Il6, Lif, and Tnf, chemokines Ccl2, Cxcl1, Cxcl2, and Cxcl10, and microRNAs miR-155, miR-146a, and miR-223 were induced by mating in wild-type mice, but not, or to a lesser extent, in Tlr4^−/− mice. CD4⁺ T cells were expanded after mating in Tlr4^+/+ but not Tlr4^−/− mice, with failure to expand peripheral CD25⁺FOXP3⁺ NRP1⁻ or thymic CD25⁺FOXP3⁺ NRP1⁺ Treg cell populations, and fewer Treg cells expressed Ki67 proliferation marker and suppressive function marker CTLA4. We conclude that TLR4 is an essential mediator of the inflammation-like response in the pre-implantation uterus that induces generation of Treg cells to support robust pregnancy tolerance and ensure optimal fetal growth and survival.

The in-utero experience of piglets born from sows with lameness shapes their life trajectory

Experiences during gestation can alter the mother's behavior and physiology, thereby potentially affecting the behavioral and physiological development of the offspring. In livestock, one common challenge for pregnant animals is lameness: a multifactorial condition that causes pain, stress, resulting in poor welfare outcomes. Since maternal pain can affect offspring development, we aimed to quantify the behavioral response in 142 piglets born from sows with different degrees of lameness during pregnancy. Gait scores of 22 pregnant group-housed sows were assessed six times at 2-week intervals. Lameness scores varied from 0 (no lameness) to 5 (most severe lameness score). Saliva samples and behavior were assessed in the sows throughout pregnancy. Sows were moved to individual farrowing pens and placental tissue was collected for glucocorticoid assessment. At 28 days of age, piglets were weaned, weighed, and regrouped by body size and sex. Skin lesions were counted for each piglet on days 28, 29, and 30 after birth. During open field and novel object tests on day 30, the vocalization and activity levels were evaluated. Piglet data were grouped by the lameness score of the sows as G1 (without lameness), G2 (moderate lameness), and G3 (severe lameness). Data analysis included ANOVA or Kruskal-Wallis tests and pairwise comparisons which were performed using Tukey and Kramer (Nemenyi) test with Tukey-Dist approximation for independent samples. G2 piglets were heavier than G3 at weaning. G1 piglets had fewer skin lesions at days 28 and 29 than G2 piglets. Moreover, G1 piglets vocalized more than G2 when they were subjected to the combined open field and novel object test. We did not identify differences among sows showing different lameness scores in the concentration of placental or salivary glucocorticoids. Lameness in pregnant sows altered the offspring's weight gain, number of skin lesions and vocalizations, together showing evidence that lameness in sows affect offspring performance and behavior.

MicroRNA: Could It Play a Role in Bovine Endometritis?

Endometritis in dairy cows is a major economic problem worldwide; without advances in lifestyle management and drug treatment, it causes high morbidity and death. Micro ribonucleic acid (miRNAs) these days is seen as an important part of gene control networks. It is a class of small nucleotides 20-25, single-stranded RNA molecules. In endometritis, the inflammatory response caused by the gram-negative bacteria Escherichia coli (E. coli) alters the expression of miRNA which can regulate the innate immune system. This manuscript reviews (1) the interaction of miRNAs with the signaling of NF-κB and dysregulation of miRNAs and NF-κB activity in endometritis and (2) the activity of miR-let-7c, miR-148a, and miR-488 in NF-κB activation and their effect on endometritis. Cows with reduced immunity are more vulnerable to transition diseases, such as endometritis. During post-partum, cows undergo stress, metabolic disorders, hormonal imbalance, negative energy balance, and changes in diet. One of the many categories of regulatory molecules, which explain its natural function and pathological impact on NF-κB dysregulation, is important to inform the complexity of the immune system and to develop treatments for endometritis. It shows that miRNAs could have multiple applications in veterinary medicine. Nevertheless, a comprehensive study of is essential which should be aimed at exploring the role of microRNA at physiological level and its effect due to dysfunction and dysregulation.

A combination of growth factors and cytokines alter preimplantation mouse embryo development, foetal development and gene expression profiles

Within the maternal tract, the preimplantation embryo is exposed to an array of growth factors (GFs) and cytokines, most of which are absent from culture media used in clinical IVF. Whilst the addition of individual GFs and cytokines to embryo culture media can improve preimplantation mouse embryo development, there is a lack of evidence on the combined synergistic effects of GFs and cytokines on embryo development and further foetal growth. Therefore, in this study, the effect of a combined group of GFs and cytokines on mouse preimplantation embryo development and subsequent foetal development and gene expression profiles was investigated. Supplementation of embryo culture media with an optimised combination of GFs and cytokines (0.05 ng/ml vascular endothelial GF, 1 ng/ml platelet-derived GF, 0.13 ng/ml insulin-like GF 1, 0.026 ng/ml insulin-like GF 2 and 1 ng/ml granulocyte colony-stimulating factor) had no effect on embryo morphokinetics but significantly increased trophectoderm cell number (P = 0.0002) and total cell number (P = 0.024). Treatment with this combination of GFs and cytokines also significantly increased blastocyst outgrowth area (P < 0.05) and, following embryo transfer, increased foetal weight (P = 0.027), crown-rump length (P = 0.017) and overall morphological development (P = 0.027). RNA-seq analysis of in vitro derived foetuses identified concurrent alterations to the transcriptional profiles of liver and placental tissues compared with those developed in vivo, with greater changes observed in the GF and cytokine treated group. Together these data highlight the importance of balancing the actions of such factors for the regulation of normal development and emphasise the need for further studies investigating this prior to clinical implementation.

Reproductive, obstetric, and perinatal outcomes of women with adenomyosis and endometriosis: a systematic review and meta-analysis

BACKGROUND

The reproductive impact of adenomyosis and endometriosis is widely researched but the extent of these impacts remains elusive. It has been demonstrated that endometriosis, in particular, is known to result in subfertility but endometriosis and adenomyosis are increasingly linked to late pregnancy complications such as those caused by placental insufficiency. At the molecular level, the presence of ectopic endometrium perturbs the endometrial hormonal, cellular, and immunological milieu, negatively influencing decidualization, placentation, and developmental programming of the embryo. It is unclear if and how such early aberrant reproductive development relates to pregnancy outcomes in endometriosis and adenomyosis.

OBJECTIVE AND RATIONALE

The aims of this systematic review and meta-analysis were to (i) investigate the association of adenomyosis and endometriosis with fertility, obstetric, and neonatal outcomes of women through both assisted reproduction and natural conception and (ii) determine whether endometriosis disease subtypes have specific impacts on different stages of the reproductive process.

SEARCH METHODS

A systematic literature review of NHS evidence electronic databases and the Cochrane database identified all comparative and observational studies between 1980 and December 2018 in any language on adenomyosis and endometriosis with fertility, obstetric, and neonatal outcomes (23 search terms used). A total of 104 papers were selected for data extraction and meta-analysis, with use of Downs and Black standardized checklist to evaluate quality and bias.

OUTCOMES

We found that endometriosis consistently leads to reduced oocyte yield and a reduced fertilization rate (FR), in line with current evidence. Milder forms of endometriosis were most likely to affect the fertilization (FR OR 0.77, CI 0.63-0.93) and earlier implantation processes (implantation rate OR 0.76, CI 0.62-0.93). The more severe disease by American Society for Reproductive Medicine staging (ASRM III and IV) influenced all stages of reproduction. Ovarian endometriosis negatively affects the oocyte yield (MD -1.22, CI -1.96, -0.49) and number of mature oocytes (MD -2.24, CI -3.4, -1.09). We found an increased risk of miscarriage in both adenomyosis and endometriosis (OR 3.40, CI 1.41-8.65 and OR 1.30, CI 1.25-1.35, respectively), and endometriosis can be associated with a range of obstetric and fetal complications including preterm delivery (OR 1.38, CI 1.01-1.89), caesarean section delivery (OR 1.98 CI 1.64-2.38), and neonatal unit admission following delivery (OR 1.29, CI 1.07-1.55).

WIDER IMPLICATIONS

Adenomyosis and the subtypes of endometriosis may have specific complication profiles though further evidence is needed to be able to draw conclusions. Several known pregnancy complications are likely to be associated with these conditions. The complications are possibly caused by dysfunctional uterine changes leading to implantation and placentation issues and therefore could potentially have far-reaching consequences as suggested by Barker's hypothesis. Our findings would suggest that women with these conditions should ideally receive pre-natal counselling and should be considered higher risk in pregnancy and at delivery, until evidence to the contrary is available. In order to expand our knowledge of these conditions and better advise on future management of these patients in reproductive and maternal medicine, a more unified approach to studying fertility and reproductive outcomes with longer term follow-up of the offspring and attention to the subtype of disease is necessary.

The Female Response to Seminal Fluid

Seminal fluid is often assumed to have just one function in mammalian reproduction, delivering sperm to fertilize oocytes. But seminal fluid also transmits signaling agents that interact with female reproductive tissues to facilitate conception and .pregnancy. Upon seminal fluid contact, female tissues initiate a controlled inflammatory response that affects several aspects of reproductive function to ultimately maximize the chances of a male producing healthy offspring. This effect is best characterized in mice, where the female response involves several steps. Initially, seminal fluid factors cause leukocytes to infiltrate the female reproductive tract, and to selectively target and eliminate excess sperm. Other signals stimulate ovulation, induce an altered transcriptional program in female tract tissues that modulates embryo developmental programming, and initiate immune adaptations to promote receptivity to implantation and placental development. A key result is expansion of the pool of regulatory T cells that assist implantation by suppressing inflammation, mediating tolerance to male transplantation antigens, and promoting uterine vascular adaptation and placental development. Principal signaling agents in seminal fluid include prostaglandins and transforming growth factor-β. The balance of male signals affects the nature of the female response, providing a mechanism of ‟cryptic female choiceˮ that influences female reproductive investment. Male-female seminal fluid signaling is evident in all mammalian species investigated including human, and effects of seminal fluid in invertebrates indicate evolutionarily conserved mechanisms. Understanding the female response to seminal fluid will shed new light on infertility and pregnancy disorders and is critical to defining how events at conception influence offspring health.

Effect of Group Embryo Culture under Low-Oxygen Tension in Benchtop Incubators on Human Embryo Culture: Prospective, Randomized, Controlled Trial

To evaluate the efficacy of group embryo culture under low-oxygen tension in benchtop incubators on human embryo development in vitro. The study was designed as a prospective, patient blind, randomized, controlled trial of a complex intervention. One hundred forty-eight women undergoing IVF were recruited in our fertility practice and randomized into two groups: intervention group (study culture strategy) or control group (control culture strategy). Intervention group embryos were cultured grouped under low-oxygen tension in benchtop incubators while control group embryos were cultured individually under atmospheric oxygen tension in large-box incubators. Using the study culture strategy, there were a significantly higher implantation rate (65.1% vs 49.2%; RR, 1.42; 95% CI, 1.17-1.73) and live birth delivery rate per embryo transfer (52.7% vs 39.5%; RR, 1.33; 95% CI, 1.02-1.75) with the first fresh embryo transfer. Cumulative implantation rate (56.7% vs 43.6%; RR, 1.30; 95% CI, 1.05-1.62) and cumulative live birth rate per embryo transfer (47.4% vs 36.2%; RR, 1.31; 95% CI, 1.01-1.69) were also statistically significantly increased in the study culture strategy. Human embryos exposed to our study culture condition strategy had statistically significant increased cumulative implantation rate and cumulative live birth rate per embryo transferred. Our findings suggest that this strategy specially favours poor quality embryos. Clinical Trial Registration Number: NCT01904006.

Cytokines hold promise for human embryo culture in vitro: results of a randomized clinical trial

OBJECTIVE

To evaluate the effects of cytokine enrichment of culture medium on embryological and clinical outcomes after intracytoplasmic sperm injection (ICSI).

DESIGN

A randomized clinical trial.

SETTING

In vitro fertilization centers.

PATIENT(S)

This trial included 443 ICSI cycles randomized into two groups.

INTERVENTION(S)

This study evaluated the influence of integration of granulocyte-macrophage colony-stimulating factor, heparin-binding epidermal growth factor-like growth factor, and leukemia inhibitory factor into culture media on human embryo development after ICSI.

MAIN OUTCOME MEASURE(S)

Ongoing pregnancy rate per a randomized participant.

RESULT(S)

Cytokine enrichment of culture medium showed improvement in ongoing pregnancy rate compared with no cytokines (106/224 [47%] vs. 78/219 [36%]; absolute rate difference [ARD] = 12; 95% confidence interval [CI], 2.5-21). This integration of cytokines also showed better rates of live birth (101/224 [45%] vs. 71/219 [33%]; ARD = 13; 95% CI, 4-21) and cumulative live birth (132/224 [60%] vs. 97/219 [44%]; ARD = 12; 95% CI, 4-20) and lower rate of pregnancy loss (27/124 [22%] vs. 37/103 [36%]; ARD = -14; 95% CI, -26 to -2) than conventional medium. Embryos developed in the cytokine-supplemented medium showed better blastocyst formation, quality, cryopreservation, and use than control medium.

CONCLUSION(S)

Integration of cytokines into human embryo culture media showed improvement in embryological and clinical outcomes after ICSI. However, the long-term effect of cytokine enrichment of a medium is still unclear and warrants further studies with longitudinal follow-up.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02420886 at ClinicalTrials.gov.

Chronic fetal hypoxia disrupts the peri-conceptual environment in next-generation adult female rats

KEY POINTS

Exposure to chronic hypoxia during gestation influences long-term health and development, including reproductive capacity, across generations. If the peri-conceptual environment in the developing oviduct is affected by gestational hypoxia, then this could have implications for later fertility and the health of future generations. In the present study, we show that the oviducts of female rats exposed to chronic hypoxia in utero have reduced telomere length, decreased mitochondrial DNA biogenesis and increased oxidative stress The results of the present study show that exposure to chronic gestational hypoxia leads to accelerated ageing of the oviduct in early adulthood and they help us understand how exposure to hypoxia during development could influence reproductive health across generations.

ABSTRACT

Exposure to chronic hypoxia during fetal development has important effects on immediate and long-term outcomes in offspring. Adverse impacts in adult offspring include impairment of cardiovascular function, metabolic derangement and accelerated ovarian ageing. However, it is not known whether other aspects of the female reproductive system may be similarly affected. In the present study, we examined the impact of chronic gestational hypoxia on the developing oviduct. Wistar rat dams were randomized to either normoxia (21%) or hypoxia (13%) from day 6 post-mating until delivery. Post-delivery female offspring were maintained in normoxia until 4 months of age. Oviductal gene expression was assayed at the RNA (quantitative RT-PCR) and protein (western blotting) levels. Oviductal telomere length was assayed using Southern blotting. Oviductal telomere length was reduced in the gestational hypoxia-exposed animals compared to normoxic controls (P < 0.01). This was associated with a specific post-transcriptional reduction in the KU70 subunit of DNA-pk in the gestational hypoxia-exposed group (P < 0.05). Gestational hypoxia-exposed oviducts also showed evidence of decreased mitochondrial DNA biogenesis, reduced mtDNA copy number (P < 0.05) and reduced gene expression of Tfam (P < 0.05) and Pgc1α (P < 0.05). In the hypoxia-exposed oviducts, there was upregulation of mitochondrial-specific anti-oxidant defence enzymes (MnSOD; P < 0.01). Exposure to chronic gestational hypoxia leads to accelerated ageing of the oviduct in adulthood. The oviduct plays a central role in early development as the site of gamete transport, syngamy, and early development; hence, accelerated ageing of the oviductal environment could have important implications for fertility and the health of future generations.

TNFα is responsible for the canonical offspring number-size trade-off

There is a canonical life-history trade-off between quantity and quality of offspring, but molecular determinants for this are unknown. Here, we show that knockout of tumor necrosis factor (TNF-KO) in mice switched a relation between the number and size of developing embryos from expectedly negative to unexpectedly positive. Depletion of TNFα imbalanced humoral and trophic maintenance of embryo growth during gestation with respect to the litter size. The levels of embryotrophic GM-CSF cytokine and placental efficiency attained positive correlations with the number and size of embryos in TNF-KO females. Thus, TNFα oversees mother’s resource allocations to balance embryo growth with the number of offspring. Consequently, this suggests an intricate link between the number-size trade-off and immunity given a pivotal role of TNFα in immune homeostasis.

Individual culture and atmospheric oxygen during culture affect mouse preimplantation embryo metabolism and post-implantation development

RESEARCH QUESTION

Does single embryo culture under atmospheric or reduced oxygen alter preimplantation metabolism and post-implantation development compared with culture in groups?

DESIGN

Mouse embryos were cultured under 5% or 20% oxygen, individually or in groups of 10. Spent media were analysed after 48, 72 and 96 h of culture. Blastocysts were assessed by outgrowth assay or transferred to pseudo-pregnant recipients, and fetal and placental weight, length and morphology were assessed.

RESULTS

Compared with group culture, individually cultured blastocysts had lower net consumption of glucose and aspartate and higher glutamate production. Atmospheric oxygen reduced uptake of glucose and aspartate and increased production of glutamate and ornithine compared with 5% oxygen. Combining 20% oxygen and single culture resulted in further metabolic changes: decreased leucine, methionine and threonine consumption. Under 5% oxygen, individual culture decreased placental labyrinth area but had no other effects on fetal and placental development or outgrowth size compared with group culture. Under 20% oxygen, however, individual culture reduced outgrowth size and fetal and placental weight compared with group-cultured embryos.

CONCLUSIONS

Preimplantation metabolism of glucose and amino acids is altered by both oxygen and individual culture, and fetal weight is reduced by individual culture under atmospheric oxygen but not 5% oxygen. This study raises concerns regarding the increasing prevalence of single embryo culture in human IVF and adds to the existing evidence regarding the detrimental effects of atmospheric oxygen during embryo culture. Furthermore, these data demonstrate the cumulative nature of stress during embryo culture and highlight the importance of optimizing each element of the culture system.

Transgenerational Impact of Environmental Change

The ability to adapt to changing environmental conditions is critical for any species to survive. Many environmental changes occur too rapidly for an organism's genome to adapt in time. Accordingly, being able to modify either its own phenotype, or the phenotype of its offspring to better suit future anticipated environmental conditions could afford an organism a significant advantage. However, a range of animal models and human epidemiological data sets are now showing that environmental factors such as changes in the quality or quantity of an individual's diet, temperature, stress or exposure to pollutants can all adversely affect the quality of parental gametes, the development of the preimplantation embryo and the health and wellbeing of offspring over multiple generations. This chapter will examine transgenerational effects of both maternal and paternal environmental factors on offspring development and wellbeing in both human and animal model studies. Changes in the epigenetic status of either parental or grand-parental gametes provide one candidate mechanism through which the impacts of environmental experience can be passed from one generation to another. This chapter will therefore also focus on the impact of parental and grand-parental diet on epigenetic transgenerational inheritance and offspring phenotype.

Maternal genitourinary infections and risk of birth defects in the National Birth Defects Prevention Study

BACKGROUND

Genitourinary infections (GUIs) are common among sexually active women. Yet, little is known about the risk of birth defects associated with GUIs.

METHODS

Using data from the National Birth Defects Prevention Study, a multisite, population-based, case-control study, we assessed self-reported maternal GUIs in the month before through the third month of pregnancy (periconception) from 29,316 birth defect cases and 11,545 unaffected controls. We calculated odds ratios (ORs) and 95% confidence intervals to estimate the risk of 52 major structural birth defects associated with GUIs. We also calculated risk of birth defects associated with each type of GUI: urinary tract infection (UTI) and sexually transmitted infection (STI).

RESULTS

In our analysis, 10% (n = 2,972) of case and 9% (n = 1,014) of control mothers reported a periconceptional GUI. A GUI was significantly associated with 11 of the 52 birth defects examined (ORs ranging from 1.19 to 2.26): encephalocele, cataracts, cleft lip, esophageal atresia, duodenal atresia/stenosis, small intestinal atresia/stenosis, colonic atresia/stenosis, transverse limb deficiency, conoventricular septal defect, atrioventricular septal defect, and secundum atrial septal defect. A periconceptional UTI was significantly associated with nine birth defects (ORs from 1.21 to 2.48), and periconceptional STI was significantly associated with four birth defects (ORs ranging from 1.63 to 3.72).

CONCLUSIONS

While misclassification of GUIs in our analysis is likely, our findings suggest GUIs during the periconceptional period may increase the risk for specific birth defects.

Effect of exogenous transforming growth factor β1 (TGF-β1) on early bovine embryo development

During preimplantation development, embryos are exposed and have the capacity to respond to different growth factors present in the maternal environment. Among these factors, transforming growth factor β1 (TGF-β1) is a well known modulator of embryonic growth and development. However, its action during the first stages of development, when the embryo transits through the oviduct, has not been yet elucidated. The objective of the present study was to examine the effect of early exposure to exogenous TGF-β1 on embryo development and expression of pluripotency (OCT4, NANOG) and DNA methylation (DNMT1, DNMT3A, DNMT3B) genes in bovine embryos produced in vitro. First, gene expression analysis of TGF-β receptors confirmed a stage-specific expression pattern, showing greater mRNA abundance of TGFBR1 and TGFBR2 from the 2- to the 8-cell stage, before embryonic genome activation. Second, embryo culture for the first 48 h in serum-free CR1aa medium supplemented with 50 or 100 ng/ml recombinant TGF-β1 did not affect the cleavage and blastocyst rate (days 7 and 8). However, RT-qPCR analysis showed a significant increase in the relative abundance of NANOG and DNMT3A in the 8-cell stage embryos and expanded blastocysts (day 8) derived from TGF-β1 treated embryos. These results suggest an early action of exogenous TGF-β1 on the bovine embryo, highlighting the importance to provide a more comprehensive understanding of the role of TGF-β signalling during early embryogenesis.

Periconception onset diabetes is associated with embryopathy and fetal growth retardation, reproductive tract hyperglycosylation and impaired immune adaptation to pregnancy

Diabetes has been linked with impaired fertility but the underlying mechanisms are not well defined. Here we use a streptozotocin-induced diabetes mouse model to investigate the cellular and biochemical changes in conceptus and maternal tissues that accompany hyperglycaemia. We report that streptozotocin treatment before conception induces profound intra-cellular protein β-O-glycosylation (O-GlcNAc) in the oviduct and uterine epithelium, prominent in early pregnancy. Diabetic mice have impaired blastocyst development and reduced embryo implantation rates, and delayed mid-gestation growth and development. Peri-conception changes are accompanied by increased expression of pro-inflammatory cytokine Trail, and a trend towards increased Il1a, Tnf and Ifng in the uterus, and changes in local T-cell dynamics that skew the adaptive immune response to pregnancy, resulting in 60% fewer anti-inflammatory regulatory T-cells within the uterus-draining lymph nodes. Activation of the heat shock chaperones, a mechanism for stress deflection, was evident in the reproductive tract. Additionally, we show that the embryo exhibits elevated hyper-O-GlcNAcylation of both cytoplasmic and nuclear proteins, associated with activation of DNA damage (ɣH2AX) pathways. These results advance understanding of the impact of peri-conception diabetes, and provide a foundation for designing interventions to support healthy conception without propagation of disease legacy to offspring.

Assisted reproduction technique outcomes for fresh versus deferred cryopreserved day-2 embryo transfer: a retrospective matched cohort study

Ovarian stimulation could adversely affect endometrial receptivity and consequently embryo implantation. One emerging strategy is the 'freeze-all' approach. Most studies have focused on blastocyst transfers, with limited research on day-2 deferred cryopreserved embryo transfers. In this large retrospective cohort study, outcomes were compared between day-2 fresh versus deferred cryopreserved embryo transfers. After matching by age and number of previous cycles, 325 cycles were included in the fresh group and 325 in the deferred cryopreserved embryo transfers group: no significant differences were found between groups in implantation (0.20 ± 0.33 versus 0.17 ± 0.31, respectively) and ongoing pregnancy rates (21.85% versus 18.46%). Independent predictors for ongoing pregnancy after a multiple logistic regression analysis were the women's age (OR = 0.92; 95% CI 0.88 to 0.97), body mass index (OR = 0.94; 95% CI 0.89 to 0.99), the number of two pronuclei embryos (OR = 1.19; 95% CI 1.04 to 1.40) and at least one grade 1 embryo transferred (OR = 1.97; 95% CI 1.26 to 3.05). In the case of a day-2 embryo transfer, outcomes after treatment with assisted reproduction techniques are similar for fresh versus deferred cryopreserved embryo transfers when pre-transfer progesterone exposures are similar in the two groups.

Microarray Analyses Reveal Marked Differences in Growth Factor and Receptor Expression Between 8-Cell Human Embryos and Pluripotent Stem Cells

Previous microarray analyses of RNAs from 8-cell (8C) human embryos revealed a lack of cell cycle checkpoints and overexpression of core circadian oscillators and cell cycle drivers relative to pluripotent human stem cells [human embryonic stem cells/induced pluripotent stem (hES/iPS)] and fibroblasts, suggesting growth factor independence during early cleavage stages. To explore this possibility, we queried our combined microarray database for expression of 487 growth factors and receptors. Fifty-one gene elements were overdetected on the 8C arrays relative to hES/iPS cells, including 14 detected at least 80-fold higher, which annotated to multiple pathways: six cytokine family (CSF1R, IL2RG, IL3RA, IL4, IL17B, IL23R), four transforming growth factor beta (TGFB) family (BMP6, BMP15, GDF9, ENG), one fibroblast growth factor (FGF) family [FGF14(FH4)], one epidermal growth factor member (GAB1), plus CD36, and CLEC10A. 8C-specific gene elements were enriched (73%) for reported circadian-controlled genes in mouse tissues. High-level detection of CSF1R, ENG, IL23R, and IL3RA specifically on the 8C arrays suggests the embryo plays an active role in blocking immune rejection and is poised for trophectoderm development; robust detection of NRG1, GAB1, -2, GRB7, and FGF14(FHF4) indicates novel roles in early development in addition to their known roles in later development. Forty-four gene elements were underdetected on the 8C arrays, including 11 at least 80-fold under the pluripotent cells: two cytokines (IFITM1, TNFRSF8), five TGFBs (BMP7, LEFTY1, LEFTY2, TDGF1, TDGF3), two FGFs (FGF2, FGF receptor 1), plus ING5, and WNT6. The microarray detection patterns suggest that hES/iPS cells exhibit suppressed circadian competence, underexpression of early differentiation markers, and more robust expression of generic pluripotency genes, in keeping with an artificial state of continual uncommitted cell division. In contrast, gene expression patterns of the 8C embryo suggest that it is an independent circadian rhythm-competent equivalence group poised to signal its environment, defend against maternal immune rejection, and begin the rapid commitment events of early embryogenesis.