According to the World Health Organization, infertility affects up to 14% of couples under reproductive age, leading to an exponential rise in the use of assisted reproduction as a route for conceiving a baby. In the same way, thousands of embryos are produced in cattle and other farm animals annually, leading to increased numbers of individuals born. All reproductive manipulations entail deviations of natural phenotypes and genotypes, with in vitro embryo technologies perhaps showing the biggest effects, although these alterations are still emerging. Most of these indications have been provided by animal models, in particular the bovine species, due to its similarities to human early embryo development. Oocytes and embryos are highly sensitive to environmental stress in vivo and in vitro. Thus, during in vitro culture, a number of stressful conditions affect embryonic quality and viability, inducing subfertility and/or long-term consequences that may reach the offspring. A high proportion of the embryos produced in vitro are arrested at a species-specific stage of development during the first cell divisions. These arrested embryos do not show signs of programmed cell death during early cleavage stages. Instead, defective in vitro produced embryos would enter a permanent cell cycle arrest compatible with cellular senescence, in which they show active metabolism and high reactive oxygen species levels. Later in development, mainly during the morula and blastocyst stages, apoptosis would mediate the elimination of certain cells, accomplishing both a physiological role in to balancing cell proliferation and death, and a pathological role preventing the transmission of damaged cells with an altered genome. The latter would acquire relevant importance in in vitro produced embryos that are submitted to stressful environmental stimuli. In this article, we review the mechanisms mediating apoptosis and senescence during early embryo development, with a focus on in vitro produced bovine embryos. Additionally, we shed light on the protective role of senescence and apoptosis to ensure that unhealthy cells and early embryos do not progress in development, avoiding long-term detrimental effects.

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Senescence and Apoptosis During in vitro Embryo Development in a Bovine Model

This article summarises and contextualises the accumulated basic and clinical data on the ERA test and addresses specific comments and opinions presented by the opponent as part of an invited debate. Progress in medicine depends on new technologies and concepts that translate to practice to solve long-standing problems. In a key example, combining RNA sequencing data (transcriptomics) with artificial intelligence (AI) led to a clinical revolution in personalising disease diagnosis and fostered the concept of precision medicine. The reproductive field is no exception. Translation of endometrial transcriptomics to the clinic yielded an objective definition of the limited time period during which the maternal endometrium is receptive to an embryo, known as the window of implantation (WOI). The WOI is induced by the presence of exogenous and/or endogenous progesterone (P) after proper oestradiol (E2) priming. The window lasts 30-36 hours and, depending on the patient, occurs between LH + 6 and LH + 9 in natural cycles or between P + 4 and P + 7 in hormonal replacement therapy (HRT) cycles. In approximately 30% of IVF cycles in which embryo transfer is performed blindly, the WOI is displaced and embryo-endometrial synchrony is not achieved. Extending this application of endometrial transcriptomics, the endometrial receptivity analysis (ERA) test couples next-generation sequencing (NGS) to a computational predictor to identify transcriptomic signatures for each endometrial stage: proliferative (PRO), pre-receptive (PRE), receptive (R) and post-receptive (POST). In this way, personalised embryo transfer (pET) may be possible by synchronising embryo transfer with each patient's WOI. Data are the only way to confront arguments sustained in opinions and/or misleading concepts; it is up to the reader to make their own conclusions regarding its clinical utility.

Endometrial Receptivity Analysis (ERA): data versus opinions.

https://www.fertstert.org/article/S0015-0282(08)01505-7/pdf

Conjoined twins in a triplet pregnancy after intracytoplasmic sperm injection and blastocyst transfer: case report and review of the literature

Objective We present a set of twins discordant for low-level mosaic trisomy 17 at amniocentesis, and we review the literature of heterokaryotypic monozygotic twins at amniocentesis. Materials and methods We describe a monozygotic twin pregnancy with discordant karyotypes and structural abnormalities. A 22-year-old, primigravid woman underwent amniocentesis at 21 weeks of gestation because of an abnormal maternal serum screening result for Down syndrome. Prenatal ultrasound revealed twin-twin transfusion syndrome but no detectable fetal structural abnormalities. Conventional cytogenetic analysis was applied on cultured amniocytes and parental bloods. Polymorphic DNA marker analysis by quantitative fluorescent polymerase chain reaction (QF-PCR) testing was performed on the DNAs extracted from cultured amniocytes, parental bloods and peripheral bloods of the twins after birth. Interphase fluorescence in situ hybridization (FISH) analysis was performed on buccal mucosal epithelial cells. Results Amniocentesis revealed a karyotype of 47,XX,+17 [3]/46,XX [23] in twin A and a karyotype of 46,XX in twin B. The parental karyotypes were normal. QF-PCR confirmed monozygotic twinning and excluded uniparental disomy (UPD) 17. At 35 weeks of gestation, a 1778-g twin A and a 2396-g twin B were delivered smoothly. Both infants had the karyotype of 46,XX in the peripheral bloods and were phenotypically normal except that twin A had preaxial polydactyly on the right hand. Postnatal QF-PCR testing confirmed monozygotic twinning. The infants were doing well at age 2 years and 7 months at follow-ups with normal physical and psychomotor development. FISH analysis on buccal mucosal epithelial cells showed trisomy 17 signals in 4.16% (4/96) cells, compared with 5% (5/101 cells) in normal control. Conclusions Monozygotic twins discordant for low-level mosaic trisomy 17 at amniocentesis without ultrasound abnormalities can have a favorable outcome. Prenatal diagnosis of twins discordant for structural abnormalities and/or chromosomal aberrations should alert the possibility of monozygotic twinning, and QF-PCR testing is useful for rapid determination of zygosity and exclusion of UPD under such a circumstance.

Monozygotic twins discordant for low-level mosaic trisomy 17 at amniocentesis in a pregnancy with a favorable outcome and a literature review of heterokaryotypic monozygotic twins at amniocentesis.

This study evaluated which endometrial preparation protocol in frozen embryo transfer (FET) cycles provides the best results for polycystic ovarian syndrome (PCOS) patients and the general population. This retrospective study of 634 FET cycles was conducted 2016-2018. Cycles were divided into Group A: Artificial endometrial preparations for FET (aFET; n = 348), Group B: Ovulatory cycle (n = 286) to compare two methods of endometrial preparation for FET. Artificial endometrial preparation with exogenous estrogen and progesterone versus natural ovulation cycles, modified natural cycles using hCG for the final triggering and letrozole-induced ovulation with hCG. Anovulatory patients were analyzed separately. Anovulatory PCOS patients had significantly higher pregnancy rates with letrozole treatment compared with aFET cycles (44% vs. 22.5%; p = 0.044). For the entire cohort, ovulatory cycles and aFET were similar in terms of patient characteristics, demographics, infertility causes, treatment protocols and number of embryos transferred. Although the mean ESHRE score of the transferred embryos was higher in the aFET group, we found higher clinical pregnancy rate in the ovulatory cycle FET (41.3% vs. 27.3%, p < 0.0001). A better pregnancy rate was found after ovulatory cycle FET. In the ovulatory cycles, the outcome of letrozole-induced and non-induced cycles were comparable. PCOS patients, as well as the general population, may benefit from ovulation induced FET cycles, with significantly better outcomes in FET in ovulatory cycles.

Ovulatory-Based FET Cycles May Achieve Higher Pregnancy Rates in the General Population and among Anovulatory Women.

Introduction A successful embryo implantation is crucial for a positive outcome of in vitro fertilization. But there is only a short period during which the endometrium is receptive for embryo, this so called implantation window can be detected by a molecular diagnostic method endometrial receptivity analysis (ERA). Objective To find out the percentage of patients with a non-receptive endometrium in the time of ERA and to learn what part of them got pregnant after the identification of their personalized implantation window. Design A retrospective study. Setting REPROMEDA Biology Park, Centre of Reproductive Medicine and Preimplantation Genetic Diagnosis, Brno. Methods A cohort of 85 patients undergoing ERA from August 2015 to October 2018 was studied. 74 patients experienced a previous implantation failure, the average number of preceding unsuccessful frozen embryo transfers was 2,5 in this group, 11 women went through ERA due to the preventive reason before the first FET. In all women one euploid embryo was transferred. 48 patients were prepared either for ERA or FET in a natural menstrual cycle, 37 women in HRT cycle. We were interested in a percentage of non-receptive patients in the time of ERA and wanted to discover what part of non-receptive women got pregnant after the identification of their personal implantation window. The average number of frozen embryo transfers needed to achieve the pregnancy was also calculated. Results 31 of 85 patients (36.5%) were found to have a non-receptive endometrium. In the natural cycle 13 of 48 (27.1%) were non-receptive: five were pre-receptive, three early receptive, two late receptive and three post-receptive. In the HRT cycle 18 of 37 patients (48.6%) were non-receptive: 12 were pre-receptive, four early receptive, one late receptive, one post-receptive. Personalized FET was done in 26 of total 31 initially non-receptive patients, 18 of them got pregnant (69.2%). In the natural cycle 6 of 11 (54.5%) achieved the pregnancy, in the HRT cycle 12 of 15 women (80.0%) got pregnant. To achieve the clinical pregnancy 1.5 frozen embryo transfer in average was needed. Conclusion A displaced implantation window was found in more than 1/3 of patients undergoing an assisted reproductive treatment. After the personalized FET the clinical pregnancy was noticed in 69.2% of them. This result supports an individual approach to patients in IVF programme besides other at the timing of embryo transfer after the identification of pWOI.

Endometrial Receptivity Analysis - a tool to increase an implantation rate in assisted reproduction.

Purpose
To report a case of monozygotic monochorial diamniotic twins with discordant karyotypes.

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Monozygotic twins with discordant karyotypes following preimplantation genetic screening and single embryo transfer: case report

Background Assisted reproduction, as well as pregnancy itself, in patients with breast cancer or other hereditary type of cancer, is a widely discussed topic. In the past, patients treated for breast cancer were rarely involved in the discussion about reproductive possibilities or infertility treatment. However, current knowledge suggests, that breast cancer is neither a contraindication to pregnancy, nor to assisted reproduction techniques. On the contrary, assisted reproduction and preimplantation genetic diagnosis methods might prevent the transmission of genetic risks to the fetus. Aim In this review we summarize data concerning pregnancy risks in patients with increased risk of breast cancer. In addition, we introduce current possibilities and approaches to fertility preservation prior to assisted reproduction treatment as well as novel methods improving the safety of fertility treatment. In the second part of this review, we focus on karyomapping--an advanced molecular genetic tool for elimination of germinal mutations in patients with predisposition to cancer. Moreover, the rapid development of preimplantation genetic diagnosis methods contributes to detection of both chromosomal aneuploidy and causal mutations in a relatively short time-span.

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Lenka Hromadova

Papers

Endometrial Receptivity Analysis - a tool to increase an implantation rate in assisted reproduction.

Monozygotic twins with discordant karyotypes following preimplantation genetic screening and single embryo transfer: case report

Assisted Reproduction and Preimplantation Genetic Diagnosis in Patients Susceptible to Breast Cancer