The effects of temperature variation treatments on embryonic development: a mouse study.

Since the development of ART, embryos have been cultured at 37 °C in an attempt to mimic the in vivo conditions and the average body temperature of an adult. However, a gradient of temperatures within the reproductive tract has been demonstrated in humans and several other mammalian species. Therefore, the aim of this study was to evaluate the effects of temperature variation treatments on mouse embryo quality through morphokinetic events, blastocyst morphology, the relative gene expression of Igf2, Bax, Bcl2 and Apaf1 and the metabolomics of individual culture media.

Is pre-freeze sperm preparation more advantageous than post-freeze?

Unlabelled: Human sperm cryopreservation is characterised to this day by sub-optimal success rates. Interestingly, a traditional approach to improving post-thaw outcome has been to integrate standard sperm preparation techniques into freezing protocols as a means of selecting sperm with the highest fertilisation potential prior to insemination. However, no consensus has been reached yet regarding the optimal timing (before or after freezing) of this selection step.

Evaluating the influence of progesterone concentration and time of exposure on in vitro endometrial decidualisation.

This study aimed to evaluate the influence of progesterone (concentration and time of exposure) on endometrial decidualisation using an in vitro model cell line: Human Endometrial Stromal Cells (HESCs). HESCs exposed to progesterone (1 and 10 μM) had higher percentages of decidualised cells and higher expression of the decidual marker (Insulin Like Growth Factor Binding Protein 1 (IGFBP1)) compared with those exposed to (0.1 μM).

Suboptimal mid-luteal progesterone concentrations are associated with aberrant endometrial gene expression, potentially resulting in implantation failure.

Research Question: What is the difference in endometrial transcriptomics between women with normal and with low mid-luteal progesterone during the implantation window?

Design: An endometrial biopsy and serum progesterone concentration were taken from participants during the mid-luteal phase (LH+7 to LH+9). A total of 12 participants were recruited and categorized into two groups based on their progesterone concentrations: normal progesterone (>15 ng/ml, n = 6) and low progesterone (<15 ng/ml, n = 6). Global endometrial gene expression between the two groups was compared by microarray techniques.

Apoptosis triggers the release of microRNA miR-294 in spent culture media of blastocysts.

Purpose: To study whether members of the miR-290-295 cluster in spent culture medium (SCM) of embryos are correlated with morphokinetics and apoptosis.

Methods: Cryopreserved 1-cell stage mouse embryos were cultured to the blastocyst stage, development was monitored by time-lapse, 59 SCM were collected, and miR-291a and miR-294 were detected with polymerase chain reaction (PCR). Blastocysts were immuno-stained for sexing (H2AK119ub) and for apoptosis (TUNEL).

The strength of evidence supporting luteal phase progestogen after assisted reproduction: A systematic review with reference to trial registration and pre-specified endpoints.

Objective: To measure the potential for outcome switching and selective reporting, in trials of luteal phase progestogen in assisted reproduction.

Study Design: Trials identified through Medline and Embase in August 2017 using the MeSH term "assisted reproductive technology, luteal phase support" and associated text words. Randomised controlled trials (RCTs) comparing progestogen of any type, dose, and route of administration, with placebo or no treatment as luteal phase support in subfertile women undergoing in vitro fertilization (IVF) or intrauterine insemination (IUI).

Improved cryopreservation of spermatozoa using vitrification: comparison of cryoprotectants and a novel device for long-term storage.

Study Question: Does cryoprotection of spermatozoa using a vitrification protocol with improved cryoprotective agents and a novel device for large storage lead to better outcomes than conventional slow freezing? Vitrification of human sperm using sucrose and dextran-based cryoprotectant (CPA4) with a new vitrification device resulted in significantly better sperm motility and progressive motility and improved DNA integrity with lower DNA fragmentation compared with conventional slow freezing.

What Is Known Already: A major limitation to clinical implementation of vitrification is the right balance between the volume of spermatozoa suspension cryopreserved and a standardised use of CPAs for survival of spermatozoa.

Study Design, Size, Duration: This was a control versus current clinical practice study using 30 fresh human semen samples to carry out the different cryoprotectant analyses followed by a further 23 semen samples to test the novel vitrification protocol.

Steroids and miRNAs in assessment of ovarian tissue damage following cryopreservation.

Ovarian cortical tissue cryopreservation is a relatively novel approach to preserving fertility in women diagnosed with cancer. However, the effects of freezing-thawing are not fully understood, mainly due to the lack of suitable methods to assess tissue's survival after thawing. Disparities in steroid production have been associated with ovarian failure by disrupting folliculogenesis, ovulation and oocyte apoptosis.

Qualifying the difficulty of embryo transfer with a visual analogue scale and assessing its impact on IVF outcomes.

The aim of this study was to determine whether a continuous visual analogue scale (VAS) is a reliable tool to grade embryo transfer (ET) difficulty when assessing IVF outcomes. No standardized grading system exists for reporting ET 'difficulty' which is typically recorded in descriptive terms. Clinicians performing 188 fresh single ETs between November 2014 and May 2016 also recorded a VAS score (0-100).

Efficacy of Dehydroepiandrosterone (DHEA) to overcome the effect of ovarian ageing (DITTO): A proof of principle double blinded randomized placebo controlled trial.

Objective: To evaluate the effect of DHEA supplementation on In-Vitro Fertilisation (IVF) outcome as assessed by ovarian response, oocyte developmental competence and live birth rates in women predicted to have poor ovarian reserve (OR). The feasibility of conducting a large trial is also assessed by evaluating the recruitment rates and compliance of the recruited participants with DHEA/placebo intake and follow-up rates.

Study Design: A single centre, double blinded, placebo controlled, randomized trial was performed over two years with 60 women undergoing in-vitro fertilisation (IVF).

Random Allocation of Blastomere Descendants to the Trophectoderm and ICM of the Bovine Blastocyst.

The first lineage specification during mammalian embryo development can be visually distinguished at the blastocyst stage. Two cell lineages are observed on the embryonic-abembryonic axis of the blastocyst: the inner cell mass and the trophectoderm. The timing and mechanisms driving this process are still not fully understood.

Early epigenetic reprogramming in fertilized, cloned, and parthenogenetic embryos.

Despite ongoing research in a number of species, the efficiency of embryo production by nuclear transfer remains low. Incomplete epigenetic reprogramming of the nucleus introduced in the recipient oocyte is one factor proposed to limit the success of this technique. Nonetheless, knowledge of reprogramming factors has increased-thanks to comparative studies on reprogramming of the paternal genome brought by sperm on fertilization-and will be reviewed here.

PARTIALLY CONSTRAINED SEX ALLOCATION AND THE INDIRECT EFFECTS OF ASSISTED REPRODUCTIVE TECHNOLOGIES ON THE HUMAN SEX RATIO.

Infertility affects around 15% of human couples and in many countries approximately 1-4% of babies are born following Assisted Reproductive Technologies (ART). Several ART techniques are used and these differentially affect the sex ratio of offspring successfully produced. These direct effects on sex ratio also have the potential to influence, indirectly, the sex ratios of offspring born to untreated couples.

Efficacy of dehydroepiandrosterone to overcome the effect of ovarian ageing (DITTO): a proof of principle randomised controlled trial protocol.

Introduction: Dehydroepiandrosterone (DHEA) has been proposed to improve pregnancy rates in women with diminished ovarian reserve undergoing in vitro fertilisation (IVF) treatment. However, evidence regarding its efficacy is supported by a limited number of randomised controlled trials (RCTs). This double-blinded RCT aims to measure the effect of DHEA supplementation prior to and during controlled ovarian hyperstimulation on ovarian response prior to IVF treatment in women predicted to have poor ovarian reserve.

Nuclear transfer in ruminants.

Ruminants were the first mammalian species to be cloned successfully by nuclear transplantation. Those experiments were designed to multiply high merit animals (Willadsen, Nature 320(6057):63-65, 1986; Prather et al., Biol Reprod 37(4):859-866, 1987; Wilmut et al.

Effects of assisted reproductive technologies on human sex ratio at birth.

Objective: To investigate the effect of assisted reproductive technology (ART) treatments on the sex ratio of babies born.

Design: Assessment of direct effects of assisted conception through retrospective data analysis on the progeny sex ratio of treated women in the United Kingdom.

Setting: The study uses the anonymized register of the Human Fertilisation and Embryology Authority.

Efficacy of dehydroepiandrosterone to improve ovarian response in women with diminished ovarian reserve: a meta-analysis.

Women with diminished ovarian reserve often respond poorly to controlled ovarian stimulation resulting in retrieval of fewer oocytes and reduced pregnancy rates. It has been proposed that pre-IVF Dehydroepiandrosterone (DHEA) adjuvant therapy may improve ovarian response and pregnancy rates in women with diminished ovarian reserve. This meta-analysis aims to investigate efficacy of DHEA as an adjuvant to improve ovarian response and IVF outcome in women with diminished ovarian reserve.

Nuclear dynamics of histone H3 trimethylated on lysine 9 and/or phosphorylated on serine 10 in mouse cloned embryos as new markers of reprogramming?

Somatic cell nuclear transfer (SCNT) is the injection of a donor nucleus into an enucleated egg. Despite the use of this technology for many years in research, it is still quite inefficient. One of the causes for this is thought to be incorrect or incomplete genome reprogramming.

Three-dimensional fluorescence in situ hybridization in mouse embryos using repetitive probe sequences.

A common problem in research laboratories that study the mammalian embryo is the limited supply of live material. For this reason, new methods are constantly being developed and existing methods for in vitro models using cells in culture are being adapted to represent embryogenesis. Three-dimensional fluorescence in situ hybridization (3D-FISH) is an important tool to study where genomic sequences are positioned within nuclei without interfering with this 3D organization.

Trichostatin A treatment of cloned mouse embryos improves constitutive heterochromatin remodeling as well as developmental potential to term.

Background: Genome reprogramming in early mouse embryos is associated with nuclear reorganization and particular features such as the peculiar distribution of centromeric and pericentric heterochromatin during the first developmental stage. This zygote-specific heterochromatin organization could be observed both in maternal and paternal pronuclei after natural fertilization as well as in embryonic stem (ES) cell nuclei after nuclear transfer suggesting that this particular type of nuclear organization was essential for embryonic reprogramming and subsequent development.

Results: Here, we show that remodeling into a zygotic-like organization also occurs after somatic cell nuclear transfer (SCNT), supporting the hypothesis that reorganization of constitutive heterochromatin occurs regardless of the source and differentiation state of the starting material.

Differential acetylation of histone H4 lysine during development of in vitro fertilized, cloned and parthenogenetically activated bovine embryos.

The oocyte is remarkable in its ability to remodel parental genomes following fertilization and to reprogram somatic nuclei after nuclear transfer (NT). To characterize the patterns of histone H4 acetylation and DNA methylation during development of bovine gametogenesis and embryogenesis, specific antibodies for histone H4 acetylated at lysine 5 (K5), K8, K12 and K16 residues and for methylated cytosine of CpG dinucleotides were used. Oocytes and sperm lacked the staining for histone acetylation, when DNA methylation staining was intense.