Exploring Visualisation for Embryology Education: A Twenty-First-Century Perspective.

Embryology and congenital malformations play a key role in multiple medical specialties including obstetrics and paediatrics. The process of learning clinical embryology involves two basic principles; firstly, understanding time-sensitive morphological changes that happen in the developing embryo and, secondly, appreciating the clinical implications of congenital conditions when development varies from the norm. Visualising the sequence of dynamic events in embryonic development is likely to be challenging for students, as these processes occur not only in three dimensions but also in the fourth dimensions of time. Consequently, features identified at any one timepoint can subsequently undergo morphological transitions into distinct structures or may degenerate and disappear. When studying embryology, learners face significant challenges in understanding complex, multiple and simultaneous events which are likely to increase student cognitive load. Moreover, the embryology content is very nonlinear. This nonlinear content presentation makes embryology teaching challenging for educators. Embryology is typically taught in large groups, via didactic lecture presentations that incorporate two-dimensional diagrams or foetal ultrasound images. This approach is limited by incomplete or insufficient visualisation and lack of interactivity.It is recommended that the focus of embryology teaching should instill an understanding of embryological processes and emphasise conceptualising the potential congenital conditions that can occur, linking pre-clinical and clinical disciplines together. A variety of teaching methods within case-based and problem-based curricula are commonly used to teach embryology. Additional and supplementary resources including animations and videos are also typically utilised to demonstrate complex embryological processes such as septation, rotation and folding.We propose that there is a need for embryology teaching in the twenty-first century to evolve. This is particularly required in terms of appropriate visualisation resources and teaching methodologies which can ensure embryology learning is relevant to real-world scenarios. Here we explore embryology teaching resources and methodologies and review existing evidence-based studies on their implementation and impact on student learning. In doing so, we aim to inform and support the practice of embryology educators and the learning of their students.

Previous infection with SARS-CoV-2 impacts embryo morphokinetics but not clinical outcomes in a time-lapse imaging system.

The goal for the present study was to investigate whether previous infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may compromise embryo morphokinetics and implantation. For that, a historical cohort study was performed in a private university-affiliated in vitro fertilization center. The study included 1628 embryos from 88 patients undergoing intracytoplasmic sperm injection (ICSI) cycles. Patients were age-matched in a 1:3 ratio to either a coronavirus disease (COVID) group, including patients with a positive SARS-CoV-2 immunoglobulin test (n = 22 patients, 386 embryos), or a control group, including patients with a negative SARS-CoV-2 immunoglobulin test (n = 66, 1242 embryos). The effect of previous infection with SARS-CoV-2 on morphokinetic events and ICSI outcomes was evaluated. Embryos derived from patients in the COVID group presented longer time to pronuclei appearance and fading, time to form two, three, four and five cells, and time to blastulation. The durations of the third cell cycle and to time to complete synchronous divisions were also significantly increased in the COVID group compared with the control group, whereas known implantation diagnosis score Day 5 ranked significantly lower in the COVID group. No differences were observed between the COVID and control groups on clinical outcomes. In conclusion, patients planning parenthood, who have recovered from COVID-19 infection, must be aware of a possible effect of the infection on embryo development potential.

Investigation of developmental toxicity of favipiravir on fetal bone and embryonic development.

BACKGROUND: Favipiravir is one of the essential antiviral drugs used for the treatment of coronavirus disease (COVID-19) in some countries. However, there is not enough information about used, especially in pregnancy. Therefore, in this study, it was aimed to determine the developmental toxicity of favipiravir on fetal bone development and embryonic development. METHODS: In this study, 16 pregnant wistar albino rats were used. The rats were divided into four groups: Control (saline) and Group A (50 mg/kg × 5 days), Group B (50 mg/kg × 1 days + 20 mg/kg × 4 days), Group C (20 mg/kg × 5 days). Solutions were administered to the rats by oral gavage from the 10th to 14th days of pregnancy, twice a day. The skeletal system development of fetuses was examined with double skeletal staining and immunohistochemical staining methods. RESULTS: A total of 72 fetuses from pregnant rats, 18 in each group, were included in the study. As a result, depending on favipiravir dose increase, in experimental groups, it was determined that the statistically significant decrease on the ossification rates of anterior and posterior extremity bones, and length and weight of fetuses. CONCLUSION: Exposure to favipiravir during pregnancy impairs bone metabolism and bone formation-resorption stages and may cause developmental delay.

Poly(I:C) exposure during in vitro fertilization disrupts first cleavage of mouse embryos and subsequent blastocyst development.

The reproductive system can be infected by a variety of double-stranded RNA viruses, which disrupt ovary function and pregnancy. However, whether viral infection directly affects early embryonic development remains unknown. Here we show that Poly(I:C), which mimics a double-stranded RNA virus, significantly impaired mouse early embryonic development in vitro, and up-regulated TLR3 and IFNα at the two cells embryo stage. Further studies indicated that Poly(I:C)-treatment caused DNA damage and abnormal spindle morphology at the first cleavage. Moreover, CDX2 and SOX2 expression was decreased while blastocyst cell apoptosis was increased. Altogether, Poly(I:C) decreased the rate of successful in vitro fertilization via DNA damage and abnormal spindle morphology at the first cleavage and inhibited early embryonic development by inducing immune response and promoting blastocyst cell apoptosis. This study provides an implication for exploring the causes of reproductive disorders in mammals and humans caused by infection of double-stranded RNA virus.

Remdesivir impairs mouse preimplantation embryo development at therapeutic concentrations.

Remdesivir (RDV) is the first antiviral drug to be approved by the US Food and Drug Administration for the treatment of COVID-19. While the general safety of RDV has been studied, its reproductive risk, including embryotoxicity, is largely unknown. Here, to gain insights into its embryotoxic potential, we investigated the effects of RDV on mouse preimplantation embryos cultured in vitro at the concentrations comparable to the therapeutic plasma levels. Exposure to RDV (2-8 µM) did not affect the initiation of blastocyst formation, although the maintenance of the cavity failed at 8 µM due to increased cell death. While exposure to 2-4 µM permitted the cavity maintenance, expressions of developmental regulator genes associated with the inner cell mass (ICM) lineage were significantly diminished. Adverse effects of RDV depended on the duration and timing of exposure, as treatment between the 8-cell to early blastocyst stage most sensitively affected cavity expansion, gene expressions, and cell proliferation, particularly of the ICM than the trophectoderm lineage. GS-441524, a major metabolite of RDV, did not impair blastocyst formation or cavity expansion, although it altered gene expressions in a manner differently from RDV. Additionally, RDV reduced the viability of human embryonic stem cells, which were used as a model for the human ICM lineage, more potently than GS-441524. These findings suggest that RDV is potentially embryotoxic to impair the pluripotent lineage, and will be useful for designing and interpreting further in vitro and in vivo studies on the reproductive toxicity of RDV.

Reproductive and developmental safety of nirmatrelvir (PF-07321332), an oral SARS-CoV-2 Mpro inhibitor in animal models.

Nirmatrelvir (PF-07321332; NMV) the antiviral component of PAXLOVID™ is a potent and selective inhibitor of the SARS-CoV-2 main protease (Mpro), which plays a critical role in viral replication. PAXLOVID, comprised of nirmatrelvir and ritonavir (used as a pharmacokinetic enhancer), is an oral therapy currently in development as a therapeutic option for those infected with SARS-CoV-2 to prevent progression to severe disease, hospitalization, and death. PAXLOVID has been shown to be efficacious against hospitalization and death in two Phase 2/3 clinical studies that evaluated non hospitalized patients both with and without high risk factors for progression to severe illness. Given that males and females of reproductive age are included in the intended patient population, we assessed the potential effects of NMV up to the limit dose of 1000 mg/kg/day in ICH guideline embryo-fetal development studies in rats and rabbits, and a fertility and early embryonic development study in rats. There were no effects on male and female fertility or early embryonic development in rats, and no severe manifestations of developmental toxicity in rats or rabbits. The lack of adverse findings reported here in nonclinical species is consistent with the intended therapeutic target of NMV (a virus specific protein not present in mammalian cells), the favorable off-target selectivity profile, and lack of genetic toxicity. The results of these nonclinical studies with NMV along with existing ritonavir safety information indicate that there are no clinically relevant risks associated with PAXLOVID administration during pregnancy and in males and females of reproductive age.

Single cell biology-a Keystone Symposia report.

Single cell biology has the potential to elucidate many critical biological processes and diseases, from development and regeneration to cancer. Single cell analyses are uncovering the molecular diversity of cells, revealing a clearer picture of the variation among and between different cell types. New techniques are beginning to unravel how differences in cell state-transcriptional, epigenetic, and other characteristics-can lead to different cell fates among genetically identical cells, which underlies complex processes such as embryonic development, drug resistance, response to injury, and cellular reprogramming. Single cell technologies also pose significant challenges relating to processing and analyzing vast amounts of data collected. To realize the potential of single cell technologies, new computational approaches are needed. On March 17-19, 2021, experts in single cell biology met virtually for the Keystone eSymposium "Single Cell Biology" to discuss advances both in single cell applications and technologies.

Lack of effects on female fertility or pre- and postnatal development of offspring in rats after exposure to AS03-adjuvanted recombinant plant-derived virus-like particle vaccine candidate for COVID-19.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection resulting in the coronavirus disease 2019 (COVID-19) has afflicted tens of millions of people in a worldwide pandemic. A recently developed recombinant Plant-Derived Virus-Like Particle Vaccine candidate for COVID-19 (CoVLP) formulated with AS03 has been shown to be well-tolerated and highly immunogenic in healthy adults. Since the target population for the vaccine includes women of childbearing potential, the objective of the study was to evaluate any untoward prenatal and postnatal effects of AS03-adjuvanted CoVLP administered intramuscularly to Sprague-Dawley female rats before cohabitation for mating (22 and 8 days prior) and during gestation (Gestation Days [GD] 6 and 19). The embryo-fetal development (EFD) cohort was subjected to cesarean on GD 21 and the pre/post-natal (PPN) cohort was allowed to naturally deliver. Effects of AS03-adjuvanted CoVLP was evaluated on pregnant rats, embryo-fetal development (EFD), during parturition, lactation and the development of the F1 offspring up to weaning Vaccination with AS03-adjuvanted CoVLP induced an antibody response in F0 females and anti-SARS-CoV-2 spike-specific maternal antibodies were detected in the offspring at the end of the gestation and lactation periods. Overall, there was no evidence of untoward effects of AS03-adjuvanted CoVLP on the fertility or reproductive performance of the vaccinated F0 females. There was no evidence of untoward effects on embryo-fetal development (including teratogenicity), or early (pre-weaning) development of the F1 offspring. These results support the acceptable safety profile of the AS03-adjuvanted CoVLP vaccine for administration to women of childbearing potential.

Ex uno, plures-From One Tissue to Many Cells: A Review of Single-Cell Transcriptomics in Cardiovascular Biology.

Recent technological advances have revolutionized the study of tissue biology and garnered a greater appreciation for tissue complexity. In order to understand cardiac development, heart tissue homeostasis, and the effects of stress and injury on the cardiovascular system, it is essential to characterize the heart at high cellular resolution. Single-cell profiling provides a more precise definition of tissue composition, cell differentiation trajectories, and intercellular communication, compared to classical bulk approaches. Here, we aim to review how recent single-cell multi-omic studies have changed our understanding of cell dynamics during cardiac development, and in the healthy and diseased adult myocardium.

Human Oocytes Express Both ACE2 and BSG Genes and Corresponding Proteins: Is SARS-CoV-2 Infection Possible?

In addition to a number of scientific and medical questions about SARS-CoV-2 infection that still need to be answered, there is also the question of how this highly virulent virus and COVID-19 disease affect gametogenesis in humans. Even more important is the question of whether the virus can also enter and infect oocytes and possibly alter them in an unknown way, which could also affect the development and status of the human embryo. The answers to these questions are still poorly known, so we reviewed the human oocyte transcriptome and proteome obtained in our previous studies and found that human oocytes from the in vitro fertilization program expressed both the ACE2 and BSG genes and the corresponding ACE2 and BSG proteins. This means that human oocytes possess the molecular 'machinery' to facilitate SARS-CoV-2 entrance and infection. According to various studies, especially in animal models, different viruses can infect oocytes, so infection of the oocyte with SARS-Cov-2 cannot be completely ruled out. A hypothetical model of human oocyte infection with this virus has been proposed.

Influence of seasonal differences on semen quality and subsequent embryo development of Belgian Blue bulls.

Belgian Blue bulls are more susceptible to high temperature and humidity index (THI) than most other cattle breeds. Here, we investigated whether high ambient temperature during summer affected semen quality and subsequent embryo development in Belgian Blue cattle. For this purpose, semen samples were collected from six healthy mature Belgian Blue bulls in March (Low THI group; THI between 30.6 and 56.4) and August 2016 (High THI group; maximum THI of 83.7 during meiotic and spermiogenic stages of spermatogenesis; 14-28 days prior to semen collection) respectively. Motility, morphology, acrosome integrity, chromatin condensation, viability, and reactive oxygen species production were assessed for frozen-thawed semen. Moreover, the efficiency of blastocyst production from the frozen-thawed semen samples of the two groups was determined in vitro. Blastocyst quality was determined by assessing inner cell mass ratio and apoptotic cell ratio. Fresh ejaculates showed a higher sperm concentration in low THI when compared to the high THI group (P ≤ 0.05), whereas semen volume, subjective motility, and total sperm output were not affected (P > 0.05). In frozen-thawed semen, total and progressive motility, viability, and straight-line velocity were lower in high THI compared to the low THI group (P < 0.05), while H2O2 concentration, aberrant chromatin condensation, and abnormal spermatozoa were higher in the high THI group (P < 0.05). Blastocyst rates were significantly higher when low THI samples were used (P < 0.05). Moreover, the total cell number and trophectoderm cells were significantly higher (P < 0.05) in blastocysts derived from low THI samples, whereas the apoptotic cell ratio was significantly higher (P < 0.01) in blastocysts derived from high THI spermatozoa. In summary, our data show that elevated ambient temperature and humidity during summer can decrease the quality of frozen-thawed spermatozoa in Belgian Blue bulls and also affect subsequent embryo development.