Human Embryos Research Articles

Man and embryo: Historicizing ideas about humanity in the study of reproduction, 18th–19th centuries

AbstractThis article is concerned with historicizing the idea that all people belong to a single collective of biological human beings. It analyzes implications and changes in the concept of “Man” over the 18th and 19th centuries, particularly in the study of reproduction and embryos. Examining gendered assumptions in 18th‐century generation systems shows how these theories described the formation of male more than female embryos. This asymmetry matched the idea that only rational males, standing above nature, were determinant for the concept of Man. In the 19th century, new studies pushed Man closer to the rest of the natural world, provoking a readjustment in definitions of Man and understandings of the human embryo. However, far from equalizing humanity, the 19th‐century concept of Man introduced a hierarchy in the human species based on different levels of embryonic and evolutionary development.

Vitrification of human blastocysts for couples undergoing assisted reproduction: an updated review

Over the past 40 years there has been a worldwide critical change in the field of assisted reproduction technology (ART), leading to the increased application of single blastocyst transfer, which is extremely important to avoid the risks of multiple pregnancy and associated complications for both mother and babies. Indeed, advancements in ART over the last few decades have been obtained thanks to several improvements, including ovarian stimulation, embryo culture conditions and, of course, progress in cryopreservation methods, especially with the application of vitrification. The ability to cryopreserve human embryos has improved significantly with vitrification compared to the initially adopted slow-freezing procedures. Since the introduction of vitrification, it has become the gold standard method to effectively cryopreserve human blastocysts. However, some new protocols are now being explored, such as the short warming procedure and even shorter exposure to the equilibration solution before vitrification, which seem to provide optimal results. Therefore, the main aim of the current narrative review, will be to illustrate the benefit of vitrification as an effective method to cryopreserve the human blastocyst and to illustrate new protocols and variations which in future may increase the performance of vitrification protocols.

Age-related and species-specific methylation changes in the protein-coding marmoset sperm epigenome.

The sperm epigenome is thought to affect the developmental programming of the resulting embryo, influencing health and disease in later life. Age-related methylation changes in the sperm of old fathers may mediate the increased risks for reproductive and offspring medical problems. The impact of paternal age on sperm methylation has been extensively studied in humans and, to a lesser extent, in rodents and cattle. Here, we performed a comparative analysis of paternal age effects on protein-coding genes in the human and marmoset sperm methylomes. The marmoset has gained growing importance as a non-human primate model of aging and age-related diseases. Using reduced representation bisulfite sequencing, we identified age-related differentially methylated transcription start site (ageTSS) regions in 204 marmoset and 27 human genes. The direction of methylation changes was the opposite, increasing with age in marmosets and decreasing in humans. None of the identified ageTSS was differentially methylated in both species. Although the average methylation levels of all TSS regions were highly correlated between marmosets and humans, with the majority of TSS being hypomethylated in sperm, more than 300 protein-coding genes were endowed with species-specifically (hypo)methylated TSS. Several genes of the glycosphingolipid (GSL) biosynthesis pathway, which plays a role in embryonic stem cell differentiation and regulation of development, were hypomethylated (<5%) in human and fully methylated (>95%) in marmoset sperm. The expression levels and patterns of defined sets of GSL genes differed considerably between human and marmoset pre-implantation embryo stages and blastocyst tissues, respectively.

Benefit from luteal phase progestin-primed ovarian stimulation with clomiphene citrate supplementation in young women with diminished ovarian reserve: a retrospective study.

To compare the pregnant outcomes of luteal phase progestin-primed ovarian stimulation (PPOS) protocol with clomiphene citrate supplementation (LPPOS+CC) and follicular phase PPOS+CC protocol (FPPOS+CC) in young women with diminished ovarian reserve (DOR). A total of 483 women aged ≤35 years with DOR, who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI)/embryo transfer (ET) with controlled ovarian stimulation using LPPOS+CC (n=257) or FPPOS+CC (n=226) protocols during June 2018 and December 2021 at the First Affiliated Hospital of Wenzhou Medical University, were included in this retrospective study. The baseline characteristics, ovarian stimulation, endocrinological indicators, clinical outcomes between the two groups, and pregnancy outcomes of women achieved at least one high-quality cleavage-stage embryo or good-morphology blastocyst between the two groups were compared. No statistically significant differences were identified between the groups with respect to number of oocytes retrieved, oocyte maturation rate, high-quality cleavage-stage embryo cycle rate, the percentage of women with profound pituitary suppression, preterm birth rate, and live birth rate (P>0.05). Compared to FPPOS+CC group, the duration of stimulation [11.0 (9.0,12.0) vs. 9.0 (8.0,11.0) d, P<0.01] was significantly longer in the LPPOS+CC group. The LH levels on the day of trigger [4.0 (2.7,5.3) vs. 5.1 (3.2,7.2) IU/L, P<0.01], the percentage of women with LH levels of >10 IU/L on the trigger day (3.13% vs. 10.67%, P<0.01), and the two pronucleate (2PN) rate of ICSI oocytes (72.16% vs. 79.56%, P<0.05) were significantly lower in the LPPOS+CC group than those in the FPPOS+CC group. The consumption of total gonadotropin [2213 (1650,2700) vs. 2000 (1575,2325) IU, P<0.01], the progesterone levels on the day of trigger [1.3 (0.8,2.9) vs. 0.9 (0.6,1.2) ng/mL, P<0.01], the clinical pregnancy rate [61.88% vs. 46.84%, P<0.01], and implantation rate [42.20% vs. 31.07%, P<0.01] in the LPPOS+CC group were significantly higher than those in the FPPOS+CC group. Compared to FPPOS+CC, the LPPOS+CC protocol appears to have better pregnancy outcomes for young women with DOR undergoing IVF-ICSI-ET.

Evaluation of Vasculogenic Factors in the Developing Embryo at Weeks Five and Seven With a Special Focus on CD133 and TIE2 Markers.

Background Human embryo vasculogenesis (blood vessel development starting from endothelial precursors) includes the ability of mesenchymal cells and pluripotent stem cells to differentiate into endothelial cells. Quantification of endothelial progenitor cells is difficult to assess during the early steps of human embryo development due to several factors, especially due to the paucity of human embryo tissue which is usually discarded after early-stage pregnancy abortive methods. CD133 (Promimin-1) is a general marker of progenitor cells, but combined with other endothelial markers such as CD34, it may identify endothelial progenitor cells during embryonic development. CD34 immunohistochemistry was previously performed by our team to identify human embryo capillaries and comparatively assess microvessel density between different human embryonic tissues.TIE2 is an angiopoietin receptor strongly involved in the newly formed blood vessel maturation due to its expression in some mesenchymal precursors for future pericytes. CD34 assesses the presence of endothelial cells but its single use does not evaluate the endothelial progenitor state as CD133 may do nor vessel maturation as TIE2 may do. Data about the dynamics of CD133/TIE2 expression in the early stages of human embryo development are scarce. Hence, in this study, we aimed tocomparatively assess the dynamic of CD133+ endothelial precursors and TIE2 expression on five and seven-week-old human embryonic tissues with a special emphasis on their expression on embryonic vascular beds. Methodology CD133 and TIE2 immunohistochemistry was performed on five and seven-week-old human embryonic tissues followed by their quantification using the Qu Path digital image analysis (DIA) automated method. Results CD133 and TIE2 showed divergent patterns of expression during the initial phases of human embryonic development, specifically in the vascular endothelium of tiny capillaries. The expression of CD133 in endothelial cells lining the perfused lumen gradually decreased from five to seven-week-old embryos. It remained expressed with greater intensity in cells located at the tip of the vascular bud that emerged into pre-existing capillaries. TIE2 was much more specific than CD133, being restricted to the level of the vascular endothelium; therefore, it was easier to quantify using digital image analysis. The endothelium of the embryonic aorta was an exception to the divergent expression, as CD133 and TIE2 were consistently co-expressed in the seven-week-old embryo. The Qu Path DIA assessment increased the accuracy of CD133 and TIE2 evaluation, being the first time they were quantified by using automated software and not manually. Conclusions High heterogeneity of CD133 and TIE2 was observed between five and seven-week-old embryonic tissues as well as between different embryonic regions from the same gestational age. The unique finding of CD133/TIE2 co-expression persistenceinside aortic endothelium needs further studies to elucidate the role of this co-expression.

Clinical Practice Guidelines for the Care of Girls and Women with Turner Syndrome.

Turner syndrome affects 50 per 100,000 females, affects multiple organs through all stages of life, necessitating multidisciplinary care. This guideline extends previous ones and includes important new advances, within diagnostics and genetics, estrogen treatment, fertility, co-morbidities, and neurocognition and neuropsychology. Exploratory meetings were held in 2021 in Europe and US culminating with a consensus meeting in Aarhus, Denmark in June 2023. Prior to this, eight groups addressed important areas in TS care: 1) diagnosis and genetics, 2) growth, 3) puberty and estrogen treatment, 4) cardiovascular health, 5) transition, 6) fertility assessment, monitoring, and counselling, 7) health surveillance for comorbidities throughout the lifespan, and 8) neurocognition and its implications for mental health and well-being. Each group produced proposals for the present guidelines, which were meticulously discussed by the entire group. Four pertinent questions were submitted for formal GRADE (Grading of Recommendations, Assessment, Development and Evaluation) evaluation with systematic review of the literature. The guidelines project was initiated by the European Society for Endocrinology and the Pediatric Endocrine Society, in collaboration with members from the European Society for Pediatric Endocrinology, the European Society of Human Reproduction and Embryology, the European Reference Network on Rare Endocrine Conditions, the Society for Endocrinology, and the European Society of Cardiology, Japanese Society for Pediatric Endocrinology, Australia and New Zealand Society for Pediatric Endocrinology and Diabetes, Latin American Society for Pediatric Endocrinology, Arab Society for Pediatric Endocrinology and Diabetes, and the Asia Pacific Pediatric Endocrine Society. Advocacy groups appointed representatives for pre-meeting discussions and the consensus meeting.

First ontogenesis and bioecological study of Sciobia bouvieri (Orthoptera, Gryllidae), a North African endemic species

This study aimed to investigate the bioecology and life cycle of the Algerian endemic Sciobia bouvieri, which remained unknown until recently. A combined approach of field sampling through direct searching and captive rearing of S. bouvieri nymphs under natural conditions was employed to determine the population ontogeny. The life cycle was found to comprise three stages: egg, nymph, and adult. The embryonic development period ranged from 22 to 30 days. Females laid an average of 9.4 ± 1.3 eggs per clutch. The nymphal stage consisted of six instars, lasting an average of 306.5 days. Adult longevity varied, with males living 32.3 ± 16.2 days and females living 23.9 ± 22.4 days. The duration of the ontogenesis cycle of Sciobia bouvieri in nature showed that it has a univoltine life cycle with summer and winter diapauses occurring during the fourth and fifth larval stages, respectively. These diapauses are likely controlled by photoperiod and temperature. This is the first study of the bioecology and life cycle of this North African endemic species.

Establishment of a new equine embryo brain primary cell culture with long-term expansion

Primary cell cultures derived from human embryo lung play a crucial role in virology by aiding virus propagation and vaccine development. These cultures exhibit a notable ability to undergo multiple subcultures, often reaching up to 70 passages. However, finding alternative primary cell cultures with similar longevity and usefulness is challenging. In this study, we introduce a novel primary culture cells derived from equine embryo brain (FEB), which cells exhibited remarkable long-term cultivation potential. The FEB was established and maintained using Sumitomo Nerve-Cell Culture System Comparison studies were conducted with fetal equine kidney cell line (FEK-Tc13) to assess growth rates and subculture longevity. Immunological characterization was performed using neuronal markers to confirm the neural nature of FEB cells. Viral growth assessments were conducted using equine herpesviruses (EHV-1 and EHV-4) to evaluate infectivity and cytopathic effects in FEB cells. PCR analysis and real-time PCR assays were employed to detect viral genomic DNA and transcription activity of EHVs in infected FEB cells. FEB cells demonstrated faster growth rates compared to fetal equine kidney cell line (FEK-Tc13 cells) and exhibited sustained subculture capability exceeding 50 passages. Immunostaining confirmed the glial identity of FEB cells. Both equine herpesviruses 1 and 4 EHV-1 and EHV-4 viruses efficiently replicated in FEB cells, resulting in clear cytopathic effects. PCR analysis detected genomic DNA of EHVs in infected FEB cells, indicating successful viral infection. The establishment of FEB cells with extended subculture capability highlights their potential utility as a model system for studying neural cell biology and viral infections.

Transcriptome analysis of long non-coding RNA associated with embryonic muscle development in chickens

ABSTRACT 1. Skeletal muscle is an important component of chicken carcass. In chickens, the number of muscle fibres is fixed during the embryonic period, and muscle development during the embryonic period determines the muscle development potential after hatching. 2. Beijing-You (BY) and Cornish (CN) chickens show completely different growth rates and body types, and two breeds were used in this study to explore the role of lncRNAs in muscle development during different chicken embryonic periods. A systematic analysis of lncRNAs and mRNAs were conducted in the pectoral muscle tissues of BY and CN chickens at embryonic days 11 (ED11), 13 (ED13), 15 (ED15), 17 (ED17), and 1-day-old (D1) using RNA-seq. A total of 4,104 differentially expressed transcripts (DETs) were identified among the five stages, including 2,359 lncRNAs and 1,745 mRNAs. 3. The number of DETs between the two breeds at ED17 (1,658 lncRNAs and 1,016 mRNAs) was much higher than the total number of DET at all the other stages (692 lncRNAs and 729 mRNAs), indicating that the two breeds show the largest difference in gene regulation at ED17. 4. Correlation analysis was performed for all differentially expressed lncRNAs and mRNAs during the five periods. Forty-three, cis interaction pairs of lncRNA-mRNA related to chicken muscle development were predicted. The expression of four pairs was verified, and the results showed MSTRG.12395.2-FGFBP2 and MSTRG.18590.6-FMOD were significantly up-regulated in CN at ED11 compared to BY and might be important candidate genes for embryonic muscle development.

Comparing the advantages, disadvantages and diagnostic power of different non-invasive pre-implantation genetic testing: A literature review

To improve embryo transfer success and increase the chances of live birth in assisted reproductive methods, there is a growing demand for the use of pre-implantation genetic testing (PGT). However, the invasive approaches used in PGT have led to in vitro fertilization failure and abortions, increasing anxiety levels for parents. To address this, non-invasive PGT methods have been introduced, such as the detection of DNA in blastocoel fluid of blastocysts and spent culture media (SCM). These methods have proven to be minimally invasive and effective in detecting aneuploidy in the chromosomes of human embryos. This review aims to explore the different approaches to pre-implantation diagnosis, including invasive and non-invasive methods, with a particular focus on non-invasive PGT (niPGT). The search strategy involved gathering data from scientific databases such as PubMed, Google Scholar, and Science Direct using relevant keywords. The search was conducted until January 2023. In total, 22 studies have successfully reported the detection and amplification of cell-free DNA in the embryonic SCM. It is important to note that niPGT has some limitations, which include differences in indicators such as cell-free DNA amplification rate, concordance, level of maternal DNA contamination, sensitivity, and specificity between SCM samples and biopsied cells. Therefore, more extensive and detailed research is needed to fully understand niPGT’s potential for clinical applications. Key words: Spent culture media, Non-invasive pre-implantation genetic testing, Biopsy methods, Cell-free embryonic DNA.

Anomalies of Midbrain/Hindbrain Development: Malformations of Cerebellum: Diagnosis, Classification, and Rehabilitative Hypothesis

AbstractExtensive research has been conducted on the cerebellum, making it one of the most thoroughly investigated regions of the brain. It plays a fundamental role not only in motor control but also in motor learning and cognition. The development of the cerebellum is a lengthy process, beginning during the embryonic period up to the first years of life. This slow and protracted process makes it a vulnerable organ liable to different insults, responsible for many developmental disorders such as Dandy–Walker syndrome, medulloblastoma, dystroglicanopathy, pontocerebellar hypoplasia, thubulinopathies, and Jubert syndrome. Due to several factors, the true prevalence of cerebellar malformations is not known in most cases. The cerebellum undergoes development through following four fundamental stages:(1) Identification of the cerebellar region at the boundary between the midbrain and hindbrain.(2) Establishment of two cell proliferation compartments: firstly, Purkinje cells and deep cerebellar nuclei emerge from the ventricular zone of the metencephalic alar plate; secondly, granule cell precursors are generated from a separate proliferation compartment known as the upper rhombic lip.(3) Migration of granule cells toward the interior: granule precursor cells constitute the external granular layer (EGL), and during the initial postnatal year, granule cells migrate inward to their final position in the internal granular layer.(4) Formation of cerebellar circuitry and subsequent differentiation.Based on different types of involvement of the structures detected in the brain magnetic resonance, the classification of brainstem and cerebellar anomalies is divided into three categories: (1) mainly the cerebellum, (2) mainly the brain stem, and (3) both involved. This review will outline the developmental processes of the cerebellum and delve into common developmental disorders associated with it, including the Dandy–Walker syndrome, cerebellar hypoplasia, rhomboencephalosynapsis, lissencephaly, and gray matter heterotopias.

Determinants of thermal homeostasis in the preimplantation embryo: a role for the embryo's central heating system?

A number of factors may impinge on thermal homeostasis in the early embryo. The most obvious is the ambient temperature in which development occurs. Physiologically, the temperature in the lumen of the female tract is typically lower than the core body temperature, yet rises at ovulation in the human, while in an IVF setting, embryos are usually maintained at core body temperature. However, internal cellular developmental processes may modulate thermal control within the embryo itself, especially those occurring in the mitochondria which generate intracellular heat through proton leak and provide the embryo with its own 'central heating system'. Moreover, mitochondrial movements may serve to buffer high local intracellular temperatures. It is also notable that the preimplantation stages of development would generate proportionally little heat within their mitochondria until the blastocyst stage as mitochondrial metabolism is comparatively low during the cleavage stages. Despite these data, the specific notion of thermal control of preimplantation development has received remarkably scant consideration. This opinion paper illustrates the lack of reliable quantitative data on these markers and identifies a major research agenda which needs to be addressed with urgency in view of laboratory conditions in which embryos are maintained as well as climate change-derived heat stress which has a negative effect on numerous clinical markers of early human embryo development.

Foetal programming in sheep: Reproductive and productive implications

The aim of this study was to evaluate the effects of pregnant ewe nutrition on the performance of offspring in terms of meat, wool production, and reproduction. Foetal programming in sheep has focused on several aspects related to foetal growth, postnatal production, behaviour, and immunological performance. Currently, significant efforts are being made to understand the endocrine, metabolic, and epigenetic mechanisms involved in offspring development. Current studies have not only evaluated the foetal period, despite the pre-conception parental nutrition has demonstrated an effect on the foetal, embryonic, and pre-implantation periods and can generate permanent effects in the foetal and postnatal phases. The performance of offspring is the result of interactions between the genome, epigenome, and environmental interventions during conception. Several factors influence the expression of phenotypic characteristics in progenies; however, this study focused on presenting data on the effect of pregnant ewe nutrition alone on foetal growth and the productive aspects of their offspring.

Young patient with a giant gastric bronchogenic cyst: A case report and review of literature

BACKGROUND Gastric bronchogenic cysts (BCs) are extremely rare cystic masses caused by abnormal development of the respiratory system during the embryonic period. Gastric bronchial cysts are rare lesions that were first reported in 1956; as of 2023, only 33 cases are available in the PubMed online database. BCs usually have no clinical symptoms in the early stage, and imaging findings also lack specificity. Therefore, they are difficult to diagnose before histopathological examination. CASE SUMMARY A 34-year-old woman with respiratory distress presented at our hospital. Endoscopic ultrasound revealed an anechoic mass between the spleen, left kidney and gastric fundus, with hyperechogenic and soft elastography textures and with a size of approximately 6.5 cm × 4.0 cm. Furthermore, a computed tomography scan demonstrated high density between the posterior stomach and the spleen and the left kidney, with uniform internal density and a small amount of calcification. The maximum cross section was approximately 10.1 cm × 6.1 cm, and the possibility of a cyst was high. Because the imaging findings did not suggest a malignancy and because the patient required complete resection, she underwent laparotomy surgery. Intraoperatively, this cystic lesion was found to be located in the posterior wall of the large curvature of the fundus and was approximately 8 cm × 6 cm in size. Finally, the pathologists verified that the cyst in the fundus was a gastric BC. The patient recovered well, her symptoms of chest tightness disappeared, and the abdominal drain was removed on postoperative day 6, after which she was discharged on day 7 for 6 months of follow-up. She had no tumor recurrence or postoperative complications during the follow-up. CONCLUSION This is a valuable report as it describes an extremely rare case of gastric BC. Moreover, this was a very young patient with a large BC in the stomach.

The beginning of becoming a human.

According to birth certificates, the life of a child begins once their body comes out of the mother's womb. But when does their organismal life begin? Science holds a palette of answers-depending on how one defines a human life. In 1984, a commission on the regulatory framework for human embryo experimentation opted not to answer this question, instead setting a boundary, 14 days post-fertilization, beyond which any experiments were forbidden. Recently, as the reproductive technologies developed and the demand for experimentation grew stronger, this boundary may be set aside leaving the ultimate decision to local oversight committees. While science has not come closer to setting a zero point for human life, there has been significant progress in our understanding of early mammalian embryogenesis. It has become clear that the 14-day stage does in fact possess features, which make it a foundational time point for a developing human. Importantly, this stage defines the separation of soma from the germline and marks the boundary between rejuvenation and aging. We explore how different levels of life organization emerge during human development and suggest a new meaning for the 14-day stage in organismal life that is grounded in recent mechanistic advances and insights from aging studies.

Maternal and obstetric outcomes following the transfer of embryos warmed with fatty acid-supplemented solutions

BackgroundVitrification procedures decrease intracytoplasmic lipid content and impair developmental competence. Adding fatty acids (FAs) to the warming solution has been shown to recover the lipid content of the cytoplasm and improve developmental competence and pregnancy outcomes. However, the influence of the FA supplementation on live birth rates after embryo transfers and perinatal outcomes remains unknown. In the present study, we examined the influence of FA-supplemented warming solutions on live birth rates, pregnancy complications, and neonatal outcomes after single vitrified-warmed cleavage-stage embryo transfers (SVCTs).MethodsThe clinical records of 701 treatment cycles in 701 women who underwent SVCTs were retrospectively analyzed. Vitrified embryos were warmed using solutions (from April 2022 to June 2022, control group) or FA-supplemented solutions (from July 2022 to September 2022, FA group). The live birth rate, pregnancy complications, and perinatal outcomes were compared between the control and FA groups.ResultsThe live birth rate per transfer was significantly higher in the FA group than in the control group. Multivariate logistic regression analysis further demonstrated a higher probability of live births in the FA group than in the control group. Miscarriage rates, the incidence and types of pregnancy complications, the cesarean section rate, gestational age, incidence of preterm delivery, birth length and weight, incidence of low birth weight, infant sex, and incidence of birth defects were all comparable between the control and FA groups. Multivariate logistic regression analysis further demonstrated no adverse effects of FA-supplemented warming solutions.ConclusionsFA-supplemented warming solutions improved live birth rates after SVCTs without exerting any adverse effects on maternal and obstetric outcomes. Therefore, FA-supplemented solutions can be considered safe and effective for improving clinical outcomes and reducing patient burden.

Trade-off between double cleavage-stage embryos transfer and single blastocyst-stage embryo transfer in patients with few good quality embryos in antagonist cycles: a retrospective study using a propensity score matching analysis

ObjectiveThis study aimed to compare the per OPU clinical outcomes for transfer of Day 3 double cleavage-stage embryos (DET) and Day 5 single blastocyst-stage (SBT) in patients with five or fewer good quality embryos on day 3 per occyte pick-up cycle (OPU) in antagonist cycles with consideration of blastocyst formation failure.MethodsThis was a retrospective, observational cohort study of 2,116 cases of OPU treated with antagonist protocol in the affiliated Chenggong Hospital of Xiamen University between January 2013 and December 2020. DET was performed in 1,811cycles and SBT was performed in 305 cycles. The DET group was matched to the SBT group by propensity score (PS) matching according to multiple maternal baseline covariates. After PS matching, there were 303 ET cycles in each group. The primary outcomes were the cumulative live birth rate (CLBR), cumulative multiple pregnancy rate(CMPR)per OPU and the number of ET to achieve live birth per OPU. Secondary outcomes were the percentage of clinical pregnancy(CPR), live birth rate(LBR), multiple pregnancy rate(MPR).ResultsFollowing PS mating, the CLBR was slightly higher (48.8% versus 40.3% ; P = 0.041) and the CMPR was significantly higher in the DET group compared to SBT group(44.2% versus 7.9%, P < 0.001). The CPR, LBR and MPR per fresh transfer were higher in DET group compared to SBT group(50.2% versus 28.7%; 41.3% versus 21.5%;29.6% versus 0%, P < 0.001). The number of ET to achieve live birth per OPU in SBT group was obiviously more than in DET group(1.48 ± 0.578 versus 1.22 ± 0.557 ,P < 0.001).ConclusionWith a marginal difference cumulative live birth rate, the lower live birth rate per fresh transfer and higher number of ET per OPU in the SBT group suggested that it might take longer time to achieve a live birth with single blastocyst strategy. A trade-off decision should be made between efficiency and safety.

Balancing Bioethics and Legal Frontiers: А Case Study of Brazil’s Supreme Federal Court Decision on Embryonic Stem Cell Research

Background. The present work focuses on the need to protect prenatal life, which is intricately entwined with delineating the precise biological and legal juncture marking an embryo’s transition into personhood. Drawing upon bioethical insights from domestic frameworks and international jurisprudence, we compare diverse perspectives on the moral and legal standing of the embryo, including its right to life, and invoking legal principles in the context of cellular and regenerative medicine.Aim. The goal of this article is to investigate the various biosafety policy approaches governing embryonic stem cell research, ranging from outright prohibition to authorization solely for therapeutic or scientific ends. Through our analysis, we focus on the unique national context of Brazil to scrutinize the underlying rationale behind a specific legal challenge questioning the constitutionality of the BiosafetyLaw. This law, which permits the utilization of human embryonic cells for research and therapeutic purposes, raises concerns about potential infringement upon the inviolability of the right to life.Methodology. The research is based on deductive reasoning alongside formal-legal methodologies, including textual interpretation and comparative-legal analysis. The research process involved documentary, bibliographic, and virtual analytical inquiries utilizing a variety of resources such as legislative texts, monographs, academic articles, databases, and online libraries. Results. Through our examination in a distinct national context, we delineate the theoretical-philosophical and normative-ethical foundations underpinning the stances of Brazilian Supreme Court justices concerning the utilization of embryonic stem cells. Their arguments predominantly invoked significant constitutional liberties such as freedom of family planning, scientific research, and academic pursuits, intertwined with considerations of human dignity and the sanctity of life. Additionally, some justices cautioned against the potential hazards inherent in genetic manipulation.Implications. The legal and ethical ramifications of Brazil’s approach to biosafety legislation concerning embryo rights invoke the necessity for conducting neutral, unfettered scientific inquiry and regenerative therapies according to specific operational parameters. These include safeguarding the integrity of genetic inheritance, preemptive evaluation of potential risks and benefits (adherence to the precautionary principle), and ensuring informed consent for treatments. A significant hurdle consists in the need to establish robust mechanisms for overseeing research involving human embryos within the domains of biomedicine and regenerative cell therapy

Mechanics of human embryo compaction.

The shaping of human embryos begins with compaction, during which cells come into close contact1,2. Assisted reproductive technology studies indicate that human embryos fail compaction primarily because of defective adhesion3,4. On the basis of our current understanding of animal morphogenesis5,6, other morphogenetic engines, such as cell contractility, could be involved in shaping human embryos. However, the molecular, cellular and physical mechanisms driving human embryo morphogenesis remain uncharacterized. Using micropipette aspiration on human embryos donated to research, we have mapped cell surface tensions during compaction. This shows a fourfold increase of tension at the cell-medium interface whereas cell-cell contacts keep a steady tension. Therefore, increased tension at the cell-medium interface drives human embryo compaction, which is qualitatively similar to compaction in mouse embryos7. Further comparison between human and mouse shows qualitatively similar but quantitively different mechanical strategies, with human embryos being mechanically least efficient. Inhibition of cell contractility and cell-cell adhesion in human embryos shows that, whereas both cellular processes are required for compaction, only contractility controls the surface tensions responsible for compaction. Cell contractility and cell-cell adhesion exhibit distinct mechanical signatures when faulty. Analysing the mechanical signature of naturally failing embryos, we find evidence that non-compacting or partially compacting embryos containing excluded cells have defective contractility. Together, our study shows that an evolutionarily conserved increase in cell contractility is required to generate the forces driving the first morphogenetic movement shaping the human body.

Public Attitudes, Interests, and Concerns Regarding Polygenic Embryo Screening

Polygenic embryo screening (PES) is a novel technology that estimates the likelihood of developing future conditions (eg, diabetes or depression) and traits (eg, height or cognitive ability) in human embryos, with the goal of selecting which embryos to use. Given its commercial availability and concerns raised by researchers, clinicians, bioethicists, and professional organizations, it is essential to inform key stakeholders and relevant policymakers about the public's perspectives on this technology. To survey US adults to examine general attitudes, interests, and concerns regarding PES use. For this survey study, data were collected from 1 stratified sample and 1 nonprobability sample (samples 1 and 2, respectively) between March and July 2023. The surveys measured approval, interest, and concerns regarding various applications of PES. In the second sample, presentation of a list of potential concerns was randomized (presented at survey onset vs survey end). The survey was designed using Qualtrics and distributed to participants through Prolific, an online sampling firm. Sample 1 was nationally representative with respect to gender, age, and race and ethnicity; sample 2 was recruited without specific demographic criteria. Analyses were conducted between March 2023 and February 2024. Participants reported their approval, interest, and concerns regarding various applications of PES and outcomes screened (eg, traits and conditions). Statistical analysis was conducted using independent samples t tests and repeated-measures analyses of variance. Of the 1435 respondents in sample 1, demographic data were available for 1427 (mean [SD] age, 45.8 [16.0] years; 724 women [50.7%]). Among these 1427 sample 1 respondents, 1027 (72.0%) expressed approval for PES and 1169 (81.9%) expressed some interest in using PES if already undergoing in vitro fertilization (IVF). Approval among these respondents for using PES for embryo selection was notably high for physical health conditions (1109 [77.7%]) and psychiatric health conditions (1028 [72.0%]). In contrast, there was minority approval for embryo selection based on PES for behavioral traits (514 [36.0%]) and physical traits (432 [30.3%]). Nevertheless, concerns about PES leading to false expectations and promoting eugenic practices were pronounced, with 787 of 1422 (55.3%) and 780 of 1423 (54.8%) respondents finding them very to extremely concerning, respectively. Sample 2 included 192 respondents (mean [SD] age 37.7 [12.2] years; 110 men [57.3%]). These respondents were presented concerns at survey onset (n = 95) vs survey end (n = 97), which was associated with less approval (28-percentage point decrease) and more uncertainty (24 percentage-point increase) but with only slightly higher disapproval (4 percentage-point increase). These findings suggest that it is critical for health care professionals and medical societies to consider and understand the perspectives of diverse stakeholders (eg, patients undergoing IVF, clinicians, and the general public), given the absence of regulation and the recent commercial availability of PES.