[PREIMPLANTATION DEVELOPMENT OF HUMAN EMBRYOS WITH NUMERICAL CHROMOSOME ABNORMALITIES IN VITRO]

The study was focused on morphokynetic characteristics of in vitro cultured human embryos that were considered to be aneuploid or euploid according to the preimplantation genetic screening results. Among all the embryos examined only 34.2% were chromosomally balanced, while others possessed isolated or combined chromosome abnormalities. Although morphological features of cleaving pathologic and euploid embryos did not differ significantly, on the fifth day of culture chromosomally balanced specimen formed "expanded" blastocyst twice as frequently as abnormal ones. Moreover, development of 38.4% of aneuploid embryos was compromised before the initiation of cavitation. Thus, prolonged embryo culture advances selection of samples with the highest implantation potential for the transfer on the basis of the morphokynetic characteristics and helps to avoid additional genetic testing.

Mitochondrial DNA content as a viability score in human euploid embryos: less is better

OBJECTIVE

To investigate the clinical relevance of mitochondrial DNA (mtDNA) content as a viability score in human euploid embryos.

DESIGN

Retrospective analysis of mtDNA content of transferred euploid embryos.

SETTING

Reproductive genetics laboratory.

PATIENT(S)

Single-embryo transfer in 270 patients who underwent preimplantation genetic screening (205 day-3 blastomere biopsies, and 65 day-5 trophectoderm biopsies), and 10 patients with double-embryo transfer (male-female).

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Normalized mtDNA content versus nuclear DNA (nDNA) from transferred euploid embryos.

RESULT(S)

A high mtDNA copy number in euploid embryos is indicative of lower embryo viability and implantation. Using the normalized mtDNA content, we created the mitochondrial score or Mitoscore (Ms). Day-3 embryos with <34 (MsA) had an implantation rate (IR) of 59% (n = 51); those with 34-52 (MsB) had an IR of 44% (n = 52); those with 52-97 (MsC) had an IR of 42% (n = 50); and those with >97 (MsD) had an IR of 25% (n = 52). Embryos with Ms >160 (n = 22) never implanted. Day-5 embryos with <18.19 (MsA) had an IR of 81%; those with 18.19-24.15 (MsB) had an IR of 50% (n = 16); those with 24.15-50.58 (MsC) had an IR of 62% (n = 16); and those with levels >50.58 (MsD) had an IR of 18% (n = 17). Embryos with levels >60 (n = 7) never implanted.

CONCLUSION(S)

An increased amount of mtDNA in euploid embryos is related to poor implantation potential and may be indicative of reduced metabolic fuel during oocyte maturation. We are implementing Ms in our preimplantation genetic screening platform to prospectively analyze its clinical relevance.

Female offspring sired by diet induced obese male mice display impaired blastocyst development with molecular alterations to their ovaries, oocytes and cumulus cells

PURPOSE

To investigate the impacts that a paternal high fat diet (HFD) has on embryology, ovarian/cumulus cell gene expression and COC metabolism from female offspring, using a mouse model.

METHODS

Founder male mice were either fed a control diet (CD) or a HFD for 12 weeks. The HFD induced obesity but not diabetes, and founder males were then mated to normal weight CD fed female mice. Female offspring were maintained on a CD, super-ovulated, mated and the resultant zygotes were cultured to the blastocyst stage for embryo morphology, blastocyst cell number and apoptosis assessment. Ovaries and cumulus cells from offspring were collected for gene expression analysis of selected genes that maintain chromatin remodeling and endoplasmic reticulum (ER), metabolic and inflammatory homeostasis. Cumulus/oocyte complexes were also investigated for glucose uptake and lipid accumulation.

RESULTS

Female offspring sired by obese fathers produced embryos with delayed development and impaired quality, displayed increases in ovarian expression of Glut1, Glut3 and Glut4, and an increase in cumulus cell expression of Glut4. Interestingly their COCs did take up more glucose, but did accumulate more lipid.

CONCLUSIONS

A paternal HFD is associated with subfertility in female offspring despite the offspring being fed a CD and this subfertility is concomitant with ovarian/cumulus cell molecular alterations and increased lipid accumulation.

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.

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.

Is it time to shift the attention on early stages embryo development to avoid inconclusive evidence on HPV-related infertility: debate and proposal

BACKGROUND

Current evidence about in-vivo effects of HPV cannot definitively clarify the possible negative role of this worldwide common infection in early embryo development. However in-vitro evidence, seems to underline a possible negative effect of HPV in increasing blastocyst apoptosis and in reducing the endometrial implantation of trophoblastic cells. On these bases we believe that a new scientific approach is necessary to better understand the real role of male and female HPV infection in infertility and early pregnancy development.

METHODS

English literature review of manuscripts focused on HPV infection and human reproduction was conducted. We performed a critical analysis of evidence and possible bias affecting both in-vivo and in-vitro studies regarding this topic.

RESULTS

The biggest limitation of the in-vivo studies is due to the inappropriate timing of HPV effects evaluation since evidence about in-vitro studies strongly suggests that a large part of HPV negative effects occurs during a very early stage of embryo development. All the efforts of the scientific community to investigate the real role of HPV in human reproduction disorders cannot underestimate the severe BIAS of actual evidence in postulating new hypothesis and research projects which are fundamental to clarify if HPV may be associated with unexplained couples infertility and early miscarriages.

CONCLUSIONS

If the relationship between HPV gametes infection and early human reproduction step impairment will be confirmed, the HPV male and couple vaccination may represent a reliable option to improve fertility in some couples affected by infertility actually classified as "idiopathic" but maybe linked to HPV infection.

Transcriptional regulators TRIM28, SETDB1, and TP53 are aberrantly expressed in porcine embryos produced by in vitro fertilization in comparison to in vivo- and somatic-cell nuclear transfer-derived embryos

In vitro embryo production is important for research in animal reproduction, embryo transfer, transgenics, and cloning. Yet, in vitro-fertilized (IVF) embryos are generally developmentally delayed and are inferior to in vivo-derived (IVV) embryos; this discrepancy is likely a result of aberrant gene expression. Transcription of three genes implicated to be important in normal preimplantation embryo development, TRIM28, SETDB1, and TP53, was determined by quanitative PCR in IVF, somatic-cell nuclear transfer (SCNT), parthenogenetic, and IVV porcine oocytes and embryos. There was no difference in TRIM28 or SETDB1 abundance between oocytes matured in vitro versus in vivo (P > 0.05), whereas TP53 levels were higher in in vitro-matured oocytes. TRIM28 increased from metaphase-II oocytes to the 4-cell and blastocyst stages in IVF embryos, whereas IVV embryos showed a reduction in TRIM28 abundance from maturation throughout development. The relative abundance of TP53 increased by the blastocyst stage in all treatment groups, but was higher in IVF embryos compared to IVV and SCNT embryos. In contrast, SETDB1 transcript levels decreased from the 2-cell to blastocyst stage in all treatments. For each gene analyzed, SCNT embryos of both hard-to-clone and easy-to-clone cell lines were more comparable to IVV than IVF embryos. Knockdown of TRIM28 also had no effect on blastocyst development or expression of SETDB1 or TP53. Thus, TRIM28, SETDB1, and TP53 are dynamically expressed in porcine oocytes and embryos. Furthermore, TRIM28 and TP53 abundances in IVV and SCNT embryos are similar, but different from quantities in IVF embryos. Mol. Reprod. Dev. 81: 552–556, 2014. © 2014 The Authors. Published by Wiley Periodicals, Inc.

The role of leukemia inhibitory factor in tubal ectopic pregnancy

INTRODUCTION

Ectopic pregnancy is unique to humans and a leading cause of maternal morbidity and mortality. The etiology remains unknown however factors regulating embryo implantation likely contribute. Leukemia inhibitory factor (LIF) has roles in extravillous trophoblast adhesion and invasion and is present in ectopic implantation sites. We hypothesised that LIF facilitates blastocyst adhesion/invasion in the Fallopian tube, contributing to ectopic pregnancy.

METHODS

We immunolocalised LIF receptor (R) in tubal ectopic pregnancy (N = 5). We used an oviduct cell line (OE-E6/E7) to model Fallopian tube epithelial cells and a trophoblast spheroid co-culture model (HTR-8/SVneo cell line formed spheroids) to model blastocyst attachment to the Fallopian tube. We examined LIF signaling pathways in OE-E6/E7 cells by Western blot. The effect of LIF and LIF inhibition (using a novel LIF inhibitor, PEGLA) on first-trimester placental outgrowth was determined.

RESULTS

LIFR localised to villous and extravillous trophoblast and Fallopian tube epithelium in ectopic pregnancy. LIF activated STAT3 but not the ERK pathway in OE-E6/E7 cells. LIF stimulated HTR-8/SVneo spheroid adhesion to OE-E6/E7 cells which was significantly reduced after PEGLA treatment. LIF promoted placental explants outgrowth, while co-treatment with PEGLA blocked outgrowth.

DISCUSSION

Our data suggests LIF facilitates the development of ectopic pregnancy by stimulating blastocyst adhesion and trophoblast outgrowth from placental explants. Ectopic pregnancy is usually diagnosed after 6 weeks of pregnancy, therefore PEGLA may be useful in targeting trophoblast growth/invasion.

CONCLUSION

LIF may contribute to the development of ectopic pregnancies and that pharmacologically targeting LIF-mediated trophoblast outgrowth may be useful as a treatment for ectopic pregnancy.

β-catenin functions pleiotropically in differentiation and tumorigenesis in mouse embryo-derived stem cells

The canonical Wnt/β-catenin signaling pathway plays a crucial role in the maintenance of the balance between proliferation and differentiation throughout embryogenesis and tissue homeostasis. β-Catenin, encoded by the Ctnnb1 gene, mediates an intracellular signaling cascade activated by Wnt. It also plays an important role in the maintenance of various types of stem cells including adult stem cells and cancer stem cells. However, it is unclear if β-catenin is required for the derivation of mouse embryo-derived stem cells. Here, we established β-catenin-deficient (β-cat^Δ/Δ) mouse embryo-derived stem cells and showed that β-catenin is not essential for acquiring self-renewal potential in the derivation of mouse embryonic stem cells (ESCs). However, teratomas formed from embryo-derived β-cat^Δ/Δ ESCs were immature germ cell tumors without multilineage differentiated cell types. Re-expression of functional β-catenin eliminated their neoplastic, transformed phenotype and restored pluripotency, thereby rescuing the mutant ESCs. Our findings demonstrate that β-catenin has pleiotropic effects in ESCs; it is required for the differentiation of ESCs and prevents them from acquiring tumorigenic character. These results highlight β-catenin as the gatekeeper in differentiation and tumorigenesis in ESCs.

Nicotine-induced cessation of embryonic development is reversed by γ-tocotrienol in mice

BACKGROUND

This study aimed to evaluate the adverse effects of various doses of nicotine and protective effects of different concentrations of gamma-tocotrienol (gamma-TCT) on in vitro embryonic development and lipid peroxidation in mice.

MATERIAL AND METHODS

A) Effects of various doses of nicotine on in vitro embryonic development: Female mice were treated with 1.0, 3.0, or 5.0 mg/kg/day nicotine for 7 consecutive days. Animals were superovulated, cohabited overnight, and sacrificed. Embryos were cultured in vitro. Plasma was assayed. B) Effects of concomitant treatment of nicotine concurrently with various doses of gamma-TCT on in vitro embryonic development: Female mice were treated with nicotine (5.0 mg/kg/day), gavaged gamma-TCT of 30, 60, or 90 mg/kg/day or nicotine concurrently with gamma-TCT of 3 different doses for 7 consecutive days. Animals were superovulated, cohabited overnight, and sacrificed. Embryos were cultured and plasma was assayed.

RESULTS

A) Effects of various doses of nicotine on in vitro embryonic development: Number of hatched blastocysts decreased in 1.0 and 3.0 mg/kg/day nicotine groups. Nicotine at 5.0 mg/kg/day stopped embryo development at morula. MDA concentrations increased following all nicotine doses. B) Effects of concomitant treatment of nicotine concurrently with various doses of gamma-TCT on in vitro embryonic development: Embryo development was completed in all groups. MDA concentration increased only in the group treated with nicotine concurrently with 30 mg/kg/day gamma-TCT.

CONCLUSIONS

Nicotine impairs in vitro embryo development and increases MDA in plasma. The deleterious impact of nicotine on embryo development is reversed by supplementing gamma-TCT concurrently with nicotine.

Detection and quantification of maternal-effect gene transcripts in mouse second polar bodies: potential markers of embryo developmental competence

OBJECTIVE

To test the hypothesis that quantification of messenger RNAs originating from the second polar body (PB(2)) provides a noninvasive tool for assessing embryo quality.

DESIGN

Prospective study.

SETTING

Hospital-based academic research laboratory.

ANIMAL(S)

CD1 female mice.

INTERVENTION(S)

Metaphase II oocytes obtained from 7- to 8-week-old mice after pregnant mare's serum gonadotropin and hCG priming. After in vitro fertilization, the PB(2) was biopsied from zygote, followed by reverse transcription. Real-time polymerase chain reaction was performed to quantify gene expression levels in single PB(2). The sibling zygotes were continuously cultured to blastocyst stage.

MAIN OUTCOME MEASURE(S)

Embryo developmental competence and six maternal-effect gene (Dnmt1, Mater, Nobox, Npm2, Tcl1, and Zar1) transcripts in the PB(2).

RESULT(S)

Second polar body messenger RNA was detected in all candidate genes. Transcripts that were present in greater abundance in the zygote were more likely to be detected in quantitative polymerase chain reaction replicates from single PB(2). Four candidate genes (Dnmt1, Nobox, Npm2, and Tcl1) expression levels in PB(2) between two groups (two-cell embryo vs. blastocyts) approached statistical significance.

CONCLUSION(S)

Second polar bodies may contain a representative transcript profile to that of the zygote after fertilization. Differences in gene expression in PB(2) may be potential biomarkers of embryo quality.

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.

Establishment of polycystic ovary syndrome-derived human embryonic stem cell lines

BACKGROUND

Recently, human embryonic stem cells (hESCs) of some genetic diseases have been established, but little research has been done on polycystic ovary syndrome (PCOS)-derived hESCs. The establishment of PCOS-derived hESCs provides a biological basis for exploring the pathogenesis, gene mapping and gene therapy of PCOS.

METHODS

Discarded fresh embryos were collected and cultured until the blastocyst stage, and then inner cell masses (ICM) were isolated by mechanical methods and incubated in the mixed feeder layer containing human stem cell medium. hESCs were identified whether to maintain normal karyotype and pluripotency by alkaline phosphates (AKP), stage-specific embryonic antigen-4 (SSEA-4), NANOG, SOX2 and TRA-1-60, octamer binding protein 4(OCT-4), and in vivo and in vitro differentiation.

RESULTS

Of the 11 passaged ICM, nine showed adherent growths within 48 h with an adherence rate of 81.8% (9/11). Five PCOS-derived hESCs were established and all of them have the characteristics of pluripotent differentiation. One was from 2PN embryo which was retarded in the cleavage stage, one was from 1PN embryo and others were from 0PN embryo. They were named p-hES-1, p-hES-2, p-hES-3, p-hES-4, p-hES-5, respectively.

CONCLUSION

We provide biological models for studying the pathogenesiss of PCOS.

Maternal obesity promotes a proinflammatory signature in rat uterus and blastocyst

Maternal obesity at conception increases the risk of offspring obesity, thus propagating an intergenerational vicious cycle. Male offspring born to obese dams are hyperresponsive to high fat-diets, gaining greater body weight, fat mass, and additional metabolic sequelae compared to lean controls. In this report, we identify the impact of maternal obesity before conception, on the embryo, and intrauterine milieu during the periimplantation period. We conducted global transcriptomic profiling in the uterus and periimplantation blastocyst, gene/protein expression analyses of inflammatory pathways in conjunction with endocrine and metabolic characterization in the dams at implantation. Uterine gene expression profiles of lean and obese dams revealed distinct signatures for genes regulating inflammation and lipid metabolism. Both pathway and gene-set enrichment analysis revealed uterine nuclear factor-κB and c-Jun N-terminal kinase signaling to be up-regulated in the uterus of obese dams, which was confirmed via immunoblotting. Obese uteri also evidenced an inflammatory secretome with higher chemokine mRNA abundance (CCL2, CCL5, CCL7, and CxCL10) and related regulators (TLR2, CD14, and Ccr1). Increased inflammation in the uterus was associated with ectopic lipid accumulation and expression of lipid metabolic genes. Gene expression in sex-identified male periimplantation blastocyst at day postcoitum 4.5 was clearly influenced by maternal obesity (359 transcripts, ±1.4-fold), including changes in developmental and epigenetic regulators. Akin to the uterus, nuclear factor-κB-regulated proinflammatory genes (CCL4 and CCL5) increased and expression of antioxidant (GPx3) and mitochondrial (TFAM and NRF1) genes decreased in the obese embryos. Our results suggest that ectopic lipid and inflammation may link maternal obesity to increased predisposition of offspring to obesity later in life.

Embryotoxicity assays for leached components from dental restorative materials

BACKGROUND

Currently, there are no suitable assays available to evaluate the embryotoxicity of leached components from restorative dental materials.

METHODS

The effect of the medium conditioned by composites and amalgam on mouse blastocysts in vitro was tested. The materials were also subcutaneously implanted, and the effect of the medium supplemented with serum from the host blood was evaluated in the embryotoxicity assay. The embryo implantation rate in the material-transplanted mothers was also evaluated.

RESULTS

The results show that while the culture in media conditioned by amalgams did not affect blastocyst development, the medium conditioned by composites caused blastocyst degeneration and apoptosis. The development of blastocysts in a medium containing serum obtained from animals after transplantation was, however, without effect. Finally, inconsistent reduction in the implantation rate in transplanted mothers was observed.

CONCLUSIONS

In this study, we provide examples of in vitro and in vivo tests that may be used to evaluate embryotoxicity for dental materials. Our results show that leached components from our composite-material induced embryotoxicity in vitro, however, no toxicity was observed when subcutaneously implanted in vivo. This highlights the necessity of integrated in vitro and in vivo tests for valuable predictive estimation of embryotoxicity for complex materials.

Cdc20 is critical for meiosis I and fertility of female mice

Chromosome missegregation in germ cells is an important cause of unexplained infertility, miscarriages, and congenital birth defects in humans. However, the molecular defects that lead to production of aneuploid gametes are largely unknown. Cdc20, the activating subunit of the anaphase-promoting complex/cyclosome (APC/C), initiates sister-chromatid separation by ordering the destruction of two key anaphase inhibitors, cyclin B1 and securin, at the transition from metaphase to anaphase. The physiological significance and full repertoire of functions of mammalian Cdc20 are unclear at present, mainly because of the essential nature of this protein in cell cycle progression. To bypass this problem we generated hypomorphic mice that express low amounts of Cdc20. These mice are healthy and have a normal lifespan, but females produce either no or very few offspring, despite normal folliculogenesis and fertilization rates. When mated with wild-type males, hypomorphic females yield nearly normal numbers of fertilized eggs, but as these embryos develop, they become malformed and rarely reach the blastocyst stage. In exploring the underlying mechanism, we uncover that the vast majority of these embryos have abnormal chromosome numbers, primarily due to chromosome lagging and chromosome misalignment during meiosis I in the oocyte. Furthermore, cyclin B1, cyclin A2, and securin are inefficiently degraded in metaphase I; and anaphase I onset is markedly delayed. These results demonstrate that the physiologically effective threshold level of Cdc20 is high for female meiosis I and identify Cdc20 hypomorphism as a mechanism for chromosome missegregation and formation of aneuploid gametes.

Aneuploidy, an abnormal number of chromosomes, is a common defect in sperm and egg cells that is responsible for human infertility, miscarriage, and congenital birth defects. Although these developmental outcomes are prevalent in human reproduction, little is known about the molecular defects that may cause aneuploidy in germ cells. In this study, we identify Cdc20, a critical activator of the APC/C E3 ubiquitin ligase that initiates sister chromosome separation by ordering the destruction of cyclin B1 and securin, as a female infertility gene. We show that female mice with low amounts of Cdc20 have normal fitness but almost exclusively produce aneuploid embryos that fail to thrive and die early in development. The aneuploidy primarily results from chromosome segregation errors in primary oocytes that may be caused by inefficient APC/C-mediated destruction of mitotic cyclins and securin during metaphase I. Thus, our studies reveal that primary oocytes are highly dependent on Cdc20 for accurate chromosome segregation and raise the possibility that Cdc20 insufficiency may be a cause of infertility in otherwise healthy women.

Characterisation of the dynamic behaviour of lipid droplets in the early mouse embryo using adaptive harmonic generation microscopy

BACKGROUND

Lipid droplets (LD) are organelles with an important role in normal metabolism and disease. The lipid content of embryos has a major impact on viability and development. LD in Drosophila embryos and cultured cell lines have been shown to move and fuse in a microtubule dependent manner. Due to limitations in current imaging technology, little is known about the behaviour of LD in the mammalian embryo. Harmonic generation microscopy (HGM) allows one to image LD without the use of exogenous labels. Adaptive optics can be used to correct aberrations that would otherwise degrade the quality and information content of images.

RESULTS

We have built a harmonic generation microscope with adaptive optics to characterise early mouse embryogenesis. At fertilization, LD are small and uniformly distributed, but in the implanting blastocyst, LD are larger and enriched in the invading giant cells of the trophectoderm. Time-lapse studies reveal that LD move continuously and collide but do not fuse, instead forming aggregates that subsequently behave as single units. Using specific inhibitors, we show that the velocity and dynamic behaviour of LD is dependent not only on microtubules as in other systems, but also on microfilaments. We explore the limits within which HGM can be used to study living embryos without compromising viability and make the counterintuitive finding that 16 J of energy delivered continuously over a period of minutes can be less deleterious than an order of magnitude lower energy delivered dis-continuously over a period of hours.

CONCLUSIONS

LD in pre-implantation mouse embryos show a previously unappreciated complexity of behaviour that is dependent not only on microtubules, but also microfilaments. Unlike LD in other systems, LD in the mouse embryo do not fuse but form aggregates. This study establishes HGM with adaptive optics as a powerful tool for the study of LD biology and provides insights into the photo-toxic effects of imaging embryos.

Preimplantation genetic diagnosis

Preimplantation genetic diagnosis (PGD) is the screening of embryos at the cleavage stage in order to select and transfer only the desired embryo. The main indications of PGD are monogenic disorders and aneuploidy. This article reviews the recent advances in PGD methodology and presents their advantages, disadvantages and challenges. Ethical considerations arising with more widespread use of PGD for physical traits is also discussed. PGD for monogenic disorders remains the most successful indication, but is technically more challenging. PGS for aneuploidy has passed through a period of reconsideration and is now re-emerging with complete genome screening.

Follicular and luteal phase endometrial thickness and echogenic pattern and pregnancy outcome in oocyte donation cycles

PURPOSE

To study the effect of endometrial thickness (ET) and echogenic pattern (EP) in oocyte donation cycles upon pregnancy outcomes.

METHODS

Seventy-nine cycles resulting in blastocyst embryo transfer were evaluated. Donors underwent ovarian hyperstimulation using rFSH and GnRH-antagonist. Recipients were synchronized to donors using GnRH-agonist down-regulation followed by fixed dose of estrogen (E2) and progesterone (P4) following hCG. Transvaginal ultrasound (US) obtained ET and EP 10-11 days after initiation of E2 and on day of embryo transfer. Primary outcome was ET and EP in pregnant and non-pregnant cycles. Stimulation and embryology data was analyzed in donors to assess differences prior to transfer.

RESULTS

Fifty-nine cycles resulted in clinical pregnancy. No differences were observed in pregnant vs. non-pregnant cycles in proliferative or secretory ET and EP. Similar baseline and stimulation characteristics were found in pregnant and non-pregnant cycles. Regression analysis showed end thickness were not predictive of pregnancy outcomes.

CONCLUSIONS

Endometrial characteristics in recipients prior to and following progesterone were not predictive of pregnancy outcomes.

Effect of a woman's smoking status on oocyte, zygote, and day 3 pre-embryo quality in in vitro fertilization and embryo transfer program

In the present study we investigated the effect of a woman's smoking status on the quality of the oocyte, zygote, and on day 3 pre-embryo, as well as the likelihood of achieving an ongoing pregnancy at 8 weeks. Smokers presented a higher number of nonfertilized oocytes than nonsmokers (20.1% vs. 10.8% of fertilization failure), by comparable clinical pregnancy rate for smokers (40.8%; 28/72) and for nonsmokers (39.2%; 23/58).

Male age negatively impacts embryo development and reproductive outcome in donor oocyte assisted reproductive technology cycles

OBJECTIVE

To determine whether male age influences embryo development and reproductive potential in assisted reproductive technology cycles.

DESIGN

Retrospective cohort analysis.

SETTING

Private IVF center.

PATIENT(S)

One thousand twenty-three male partners participating in anonymous oocyte donation cycles.

INTERVENTION(S)

Infertile couples undergoing 1,023 anonymous oocyte donation cycles.

MAIN OUTCOME MEASURE(S)

Live birth rate.

RESULT(S)

A significant increase in pregnancy loss, decrease in live birth rate, and decrease in blastocyst formation rate were noted in men >50 years of age. There was no significant difference in implantation rate, pregnancy rate, or early embryo development through the cleavage stage (demonstrated by fertilization rate, embryo cleavage rate, percentage of nonfertilized or polyspermic embryos, rate of embryo arrest, or seven or more cell embryo development on day 3). Men < or =45 years of age had significantly more semen volume and more motile sperm than men >45 years of age. There was no significant change in sperm morphology or concentration.

CONCLUSION(S)

After controlling for female age with use of the donor oocyte model, male age >50 years significantly affected pregnancy outcomes and blastocyst formation rates. Semen volume and total motility decreased with increasing male age. Initial embryo morphology through the cleavage stage was not affected.

[Influence of "zero" magnetic field on the growth of embryonic cells and primary embryos of mouse in vitro]

The present investigation reveals that a 250-fold screening of the geomagnetic field ("zero" geomagnetic fields, 200 nT) is a biologically active factor that adversely affects embryonic cells and the processes of early embryogenesis as a whole. In particular, the cultivation of primary embryonic fibroblasts in "zero" geomagnetic fields causes reduces the capacity for adhesion and proliferation, changes the monolayer morphology and increases cell death. In a more highly organized experimental model, two-celled mouse embryos, the exposure to the "zero" field results in an increase of plasma membrane permeability for dyes, a reorganization of the cytoskeleton because of alpha-actin redistribution, and the disturbance of the spatial orientation of blastomeres. As a result, the development of two-celled mouse embryos stops, and they do not reach the stage of blastocyst. These data show the significant role of geomagnetic fields in the normal growth of embryonic cells in vitro and the regulation of mammalian embryogenesis.