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BACKGROUND: Currently, hormone replacement therapy is the main treatment in Western medicine for patients with decreased ovarian function, but these patients are not sensitive to exogenous hormones, leading to unsatisfactory therapeutic effect. Zishen-Yutai pills can nourish the blood and calm the fetus, tonify the kidney and spleen, invigorate qi and strengthen the body. Studies have confirmed that Zishen-Yutai pill is effective in reducing follicle-stimulating hormone index and improving traditional Chinese medicine symptoms in patients with diminished ovarian reserve. However, few studies have been conducted to improve the implantation rate of patients by improving endometrial receptivity. OBJECTIVE: To evaluate the effect of Zishen-Yutai pills on the clinical outcome of patients with diminished ovarian reserve undergoing frozen-thawed embryo transfer again. METHODS: A total of 300 patients with diminished ovarian reserve who underwent frozen-thawed embryo transfer to assist pregnancy after the first failure in the Center of Reproductive Medicine, Changzhou Maternal and Child Health Care Hospital from January 2019 to December 2021 were selected as the study subjects. Subjects were randomly treated with a placebo or Zishen-Yutai pills in a ratio of 1:2, with 100 cases in the treatment group and 200 cases in the control group. However, 13 patients fell off due to lack of contact, refusal to take medicine or other reasons. Finally, 90 cases in the treatment group and 197 cases in the control group were included in the study. Oral medication was administered 7 days before frozen-thawed embryo transfer transplantation at a dose of 5 g/time, 3 times/day. To investigate whether taking Zishen-Yutai pills could improve the clinical outcome of patients with diminished ovarian reserve after frozen-thawed embryo transfer again, the primary outcome measures included clinical pregnancy rate, implantation rate, abortion rate, live birth rate, offspring birth weight and birth defects. RESULTS AND CONCLUSION: Compared with the control group, the clinical pregnancy rate (P < 0.05) and implantation rate (P=0.009) were significantly increased after the oral administration of Zishen-Yutai pills. Correlation analysis showed that taking the Zishen-Yutai pill was positively correlated with the number of implanted embryos (r=0.200, P=0.001) and clinical pregnancy (r=0.235, P=0.000). There was no correlation between taking Zishen-Yutai pills and indexes of endometrial thickness and blood flow. It is indicated that Zishen-Yutai pills can improve the clinical pregnancy rate and implantation rate of frozen-thawed embryo transfer recurrence in patients with diminished ovarian reserve. [ABSTRACT FROM AUTHOR]

To study the primary objective of clinical pregnancy (CP) rate per ovarian stimulation with intrauterine insemination (OS-IUI) treatment cycle in patients with repetitive cycles up to a maximum of 8 cycles. Retrospective cohort. Large fertility clinic. A total of 37,565 consecutive OS-IUI cycles from 18,509 patients were included in this study. Those with anovulatory diagnoses, tubal factor infertility, male factor infertility, using donor sperm, canceled cycles, and those with missing data for either baseline characteristics or outcome were excluded. The CP rate was analyzed using generalized estimating equations and controlled for age, stimulation protocol, and body mass index. Clinical pregnancy was defined as intrauterine gestation with fetal heartbeat visible on ultrasound. A total of 37,565 consecutive OS-IUI cycles from 2002 through 2019 at a private practice facility were evaluated. All cycles met inclusion criteria and were used in generalized estimating equation modeling. Patients aged <35 years comprised 47.6% of the cohort. After adjustment for confounders, the mean predicted probability of CP for cycles one to 8 was 15.7% per cycle. The mean predicted probability of CP in aggregated data from cycles 2 to 4 was only 1.7% lower compared with cycle 1 as the referent (16.7% vs. 15.0%, 95% confidence interval [CI] 2nd: 0.88 {0.82, 0.95}, 3rd: 0.86 {0.79, 0.93}, 4th: 0.88 {0.79, 0.98}). However, the 15.0% mean predicted probability of CP for the second through the fourth cycle was concordant with the mean for all included cycles (15.7%). The mean predicted probability of CP of cycles 5 to 8 was not significantly different compared with the referent (16.7% vs. 16.1%, 95% CI 5th: 0.97 [0.85, 1.11], 6th: 0.93 [0.79, 1.10], 7th: 1.01 [0.81, 1.26], 8th: 1.01 [0.76, 1.34]). The modeling of consecutive cycles suggested that the adjusted cumulative predicted probability of CP from OS-IUI continues to increase with each of the 8 successive cycles. Clinical pregnancy rates are satisfactory in up to 8 consecutive OS-IUI treatment cycles. These data are useful for counseling, especially in those patients for whom in vitro fertilization is not financially or ethically feasible. [ABSTRACT FROM AUTHOR]

Background: The accurate prediction of pregnancy outcomes in in vitro fertilization (IVF) cycles is crucial. While several studies have been conducted on the predictive power of serum estradiol (E2) and β-hCG concentrations post-embryo transfer (ET) for pregnancy outcomes, there is debate on the predictive value of E2. The objective of this study was to investigate the predictive efficacy of combining serum E2 and β-hCG levels on early reproductive outcomes 12 days after embryo transfer. Methods: A total of 1521 patients with β-hCG positive values on day 12 following frozen-thawed embryo transfer (FET) with natural endometrial preparation cycles (NCs) were gathered in affiliated Women's Hospital of Jiangnan University. Using logistic regression, the relationship between pregnancy outcome and early serum E2 and β-hCG concentrations was examined. The receiver-operating characteristic (ROC) analysis was used to assess the predictive accuracy of the serum E2 and β-hCG concentrations. Results: Notable distinctions were observed in the serum E2 and β-hCG levels on the twelfth day following FET with NCs between the groups classified as clinical pregnancy group (CP Group) and biochemical pregnancy group (BP Group). In addition, the cutoff values for E2 and β-hCG on day 12 following FET with NCs in cleavage embryo group (CE Group) were 129.25 pg/mL and 156.60 mIU/mL, respectively. The threshold values for E2 and β-hCG for the blastocyst group (B Group) were 174.45 pg/mL and 217.70 mIU/mL. Serum E2 day12 and β-hCG day12 were found to be substantially linked with clinical pregnancy by logistic regression analysis. Conclusions: Serum E2 and β-hCG concentrations were found to be significantly different between the CP Group and BP Group in infertility women underwent FET with NCs. Our retrospective cohort study's findings suggest that the combination of early E2 and β-hCG levels on day 12 post-FET could be used as a predictive tool to evaluate the likelihood of both positive and negative pregnancy outcomes in FET with NCs. [ABSTRACT FROM AUTHOR]

Purpose: This study was aimed to systematically evaluate the efficacy of artificial cycle-prepared frozen–thawed embryo transfer (FET) with or without gonadotrophin-releasing hormone agonist (GnRH-a) pretreatment for women with polycystic ovary syndrome (PCOS). Methods: The analysis was carried out by searching the PubMed, EMBASE, and CNKI databases with a combination of keywords before October 2021. The available studies of the effects of GnRH-a pretreatment or no pretreatment on FET in PCOS patients were considered. The risk ratios (RRs) or standardized mean differences (SMD) with 95% confidence intervals (CIs) were calculated with using subgroups and sensitivity analysis. The quality evaluation for this analysis was followed. Results: Seventeen studies including 3646 women were analyzed. GnRH-a pretreatment was significantly associated with a higher implantation rate (RR = 1.12, 95%CI: 1.00–1.24) and clinical pregnancy rate (RR = 1.19, 95%CI: 1.08–1.32) than the placebo. Moreover, in the GnRH-a pretreatment group, significant differences were detected for increasing the endometrium thickness among PCOS patients (SMD = 0.56, 95%CI: 0.20–0.92). However, for RCTs subgroup, no differences were observed, even after sensitivity analyses. In addition, the miscarriage rates, ectopic pregnancy rates, multiple pregnancy rates, and live birth rates were similar in both two groups. Conclusions: Endometrial preparation using GnRH agonist pretreatment prior to FET seems to be the better choice for PCOS patients. However, well-designed RCTs are required for confirmation. [ABSTRACT FROM AUTHOR]

Early trophoblast differentiation is crucial for embryo implantation, placentation and fetal development. Dynamic changes in DNA methylation occur during preimplantation development and are critical for cell fate determination. However, the underlying regulatory mechanism remains unclear. Recently, we derived morula-like expanded potential stem cells from human preimplantation embryos (hEPSC-em), providing a valuable tool for studying early trophoblast differentiation. Data analysis on published datasets showed differential expressions of DNA methylation enzymes during early trophoblast differentiation in human embryos and hEPSC-em derived trophoblastic spheroids. We demonstrated downregulation of DNA methyltransferase 3 members (DNMT3s) and upregulation of ten-eleven translocation methylcytosine dioxygenases (TETs) during trophoblast differentiation. While DNMT inhibitor promoted trophoblast differentiation, TET inhibitor hindered the process and reduced implantation potential of trophoblastic spheroids. Further integrative analysis identified that glutamyl aminopeptidase (ENPEP), a trophectoderm progenitor marker, was hypomethylated and highly expressed in trophoblast lineages. Concordantly, progressive loss of DNA methylation in ENPEP promoter and increased ENPEP expression were detected in trophoblast differentiation. Knockout of ENPEP in hEPSC-em compromised trophoblast differentiation potency, reduced adhesion and invasion of trophoblastic spheroids, and impeded trophoblastic stem cell (TSC) derivation. Importantly, TET2 was involved in the loss of DNA methylation and activation of ENPEP expression during trophoblast differentiation. TET2-null hEPSC-em failed to produce TSC properly. Collectively, our results illustrated the crucial roles of ENPEP and TET2 in trophoblast fate commitments and the unprecedented TET2-mediated loss of DNA methylation in ENPEP promoter. [ABSTRACT FROM AUTHOR]

Recent studies have shifted the spotlight from adult disease to gametogenesis and embryo developmental events, and these are greatly affected by various environmental chemicals, such as drugs, metabolites, pollutants, and others. Growing research has highlighted the critical importance of identifying and understanding the roles of chemicals in reproductive biology. However, the functions and mechanisms of chemicals in reproductive processes remain incomplete. We developed a comprehensive database called the Reproductive Chemical Database (RCDB) (https://yu.life.sjtu.edu.cn/ChenLab/RCDB) to facilitate research on chemicals in reproductive biology. This resource is founded on rigorous manual literature extraction and precise protein target prediction methodologies. This database focuses on the delineation of chemicals associated with phenotypes, diseases, or endpoints intricately associated with four important reproductive processes: female and male gamete generation, fertilization, and embryo development in human and mouse. The RCDB encompasses 93 sub-GO processes, and it revealed 1447 intricate chemical–biological process interactions. To date, the RCDB has meticulously cataloged and annotated 830 distinct chemicals, while also predicting 614 target proteins from a selection of 3800 potential candidates. Additionally, the RCDB offers an online predictive tool that empowers researchers to ascertain whether specific chemicals play discernible functional roles in these reproductive processes. The RCDB is an exhaustive, cross-platform, manually curated database, which provides a user-friendly interface to search, browse, and use reproductive processes modulators and their comprehensive related information. The RCDB will help researchers to understand the whole reproductive process and related diseases and it has the potential to promote reproduction research in the pharmacological and pathophysiological areas. [ABSTRACT FROM AUTHOR]

Analysis of single cell transcriptomics (scRNA-seq) data is typically performed after subsetting to highly variable genes (HVGs). Here, we show that Entropy Sorting provides an alternative mathematical framework for feature selection. On synthetic datasets, continuous Entropy Sort Feature Weighting (cESFW) outperforms HVG selection in distinguishing cell-state-specific genes. We apply cESFW to six merged scRNA-seq datasets spanning human early embryo development. Without smoothing or augmenting the raw counts matrices, cESFW generates a high-resolution embedding displaying coherent developmental progression from eight-cell to postimplantation stages and delineating 15 distinct cell states. The embedding highlights sequential lineage decisions during blastocyst development, while unsupervised clustering identifies branch point populations obscured in previous analyses. The first branching region, where morula cells become specified for inner cell mass or trophectoderm, includes cells previously asserted to lack a developmental trajectory. We quantify the relatedness of different pluripotent stem cell cultures to distinct embryo cell types and identify marker genes of naïve and primed pluripotency. Finally, by revealing genes with dynamic lineage-specific expression, we provide markers for staging progression from morula to blastocyst. [ABSTRACT FROM AUTHOR]

Simple Summary: Simple Summary: Embryo reinsertion into the same donor mare after embryo flushing would be useful for some reproductive techniques. However, this procedure has been unsuccessful in the past. This study envisages to gain insights into the mechanisms by which embryos fail after embryo flushing and reinsertion in the same mare. The results of this study showed that embryo mortality after embryo reinsertion is not due to luteal deficiency. In contrast, it seems that changes in the endometrial environment due to bacterial contamination and/or inflammation during the uterine lavage are more likely to be responsible for the destruction of most reinserted embryos. The effect of embryo reinsertion immediately after embryo flushing was studied. In Experiment 1, eight mares were used during 32 cycles (8 cycles in each group). For the first two groups, inseminated mares were flushed 8 days after ovulation and prostaglandin F2α was not administered: in group EF-ET (embryo flushing and embryo transfer) the embryo was reinserted in the same donor mare, while in the EF group, no further procedure was performed. In the third group (ET), non-inseminated mares (recipients) received a Day 8 embryo. Progesterone concentration was measured before EF/ET and 72 h after in the three groups. In Experiment 2, twelve mares were used during 17 cycles in two groups, EF-ET (n = 11) and ET (n = 6), as in Experiment 1, except that every mare was flushed 24 h after embryo transfer to retrieve the embryo. Fewer pregnancies resulted after transfer in EF-ET cycles (0/8, 0%) than in the ET group (6/8, 75%). Progesterone concentration decreased significantly (p = 0.05) 72 h after EF-ET but not in EF or ET cycles (p > 0.1). Three mares from the EF-ET showed full luteolysis and signs of endometritis. In Experiment 2, more (5/6; p = 0.08) grade 1 embryos were recovered in the ET compared to the EF-ET group (3/7); 4 embryos were graded 3–4 (were broken or had signs of degeneration) in the EF-ET group but none in the ET group. In both groups, capsule fragments were obtained as indicative of the presence of a recently destroyed embryo in the EF-ET (n = 3) and ET (n = 1) groups. Positive bacterial cultures were obtained in 2/11 and 1/6 embryo flushes from the EF-ET and ET groups, respectively. [ABSTRACT FROM AUTHOR]

Reduced oxygen during embryo culture in human ART prevents embryo oxidative stress. Oxidative stress is also the major mechanism by which maternal diabetes impairs embryonic development. This study employed induced hyperglycemia prepubertal mice to mimic childhood diabetes to understand the effects of varying oxygen tension during in vitro embryonic development. The oocytes were fertilized and cultured at low (≈5%) oxygen (LOT) or atmospheric (≈20%) oxygen tension (HOT) for up to 96 h. Embryo development, apoptosis in blastocysts, inner cell mass (ICM) outgrowth proliferation, and Hif1α expression were assessed. Though the oocyte quality and meiotic spindle were not affected, the fertilization rate (94.86 ± 1.18 vs. 85.17 ± 2.81), blastocyst rate (80.92 ± 2.92 vs. 69.32 ± 2.54), and ICM proliferation ability (51.04 ± 9.22 vs. 17.08 ± 3.05) of the hyperglycemic embryos were significantly higher in the LOT compared to the HOT group. On the other hand, blastocysts from the hyperglycemic group, cultured at HOT, had a 1.5-fold increase in apoptotic cells compared to the control and lower Hif1α transcripts in ICM outgrowths compared to the LOT. Increased susceptibility of embryos from hyperglycemic mice to higher oxygen tension warrants the need to individualize the conditions for embryo culture systems in ART clinics, particularly when an endogenous maternal pathology affects the ovarian environment. [ABSTRACT FROM AUTHOR]

Purpose: This systematic review and meta-analysis aimed to compare the therapeutic effects of rFSH versus uFSH/uHMG on ovarian stimulation in women undergoing assisted reproductive technology. Methods: The databases of PubMed, Embase, and the Cochrane Library were systematically searched to retrieve data on eligible trials from inception until July 2022. The relative risks (RRs) or weighted mean differences (WMDs) with 95% confidence intervals (CIs) were applied to assess categorical and continuous outcomes, and the pooled results were calculated using the random-effects model. Sensitivity, subgroup, and publication bias analyses were also performed. Results: Forty-eight trials that enrolled 10,127 women were included in this quantitative meta-analysis. There were no significant differences between rFSH and uFSH/uHMG in the clinical pregnancy rate (RR: 1.01; 95% CI 0.95–1.07; P = 0.760), live birth rate (RR: 0.98; 95% CI 0.91–1.06; P = 0.665), multiple pregnancy rate (RR: 0.92; 95% CI 0.77–1.09; P = 0.320), miscarriage rate (RR: 1.17; 95% CI 0.94–1.46; P = 0.151), and the incidence of ovarian hyperstimulation syndrome (RR: 1.25; 95% CI 0.91–1.70; P = 0.164). In addition, the administration of rFSH was associated with a higher number of oocyte retrieval compared with that of uFSH/uHMG (WMD: 0.61; 95% CI 0.03–1.20; P = 0.038), while no significant differences were found between rFSH and uFSH/uHMG in the dosage of gonadotrophin (WMD: 14.80; 95% CI − 136.97 to 166.57; P = 0.848) and the duration of ovarian stimulation (WMD: − 0.26; 95% CI − 0.62 to 0.10; P = 0.152). Thus, the exploratory analyses revealed several potential differences in the effects of rFSH versus uFSH/uHMG on ovarian stimulation. Conclusion: The administration of rFSH significantly increased the number of oocytes retrieved, whereas there were no significant differences between the efficacies of rFSH and uFSH/uHMG for pregnancy outcomes. [ABSTRACT FROM AUTHOR]

In this article, we explore the legalisation of mitochondrial donation in the UK as the latest iteration of an established sociotechnical imaginary of permissive yet highly scrutinised human embryo research in the country. The focus of our analysis is the work of the UK House of Commons Science and Technology Select Committee as it contributed to the debates and ultimately played a role in enabling the UK to become the first country in the world to legalise clinical use. Mitochondrial donation is a reproductive technology which could allow women with mitochondrial disease to have healthy, genetically related children. From 2011, an extensive process of inquiry was launched in the UK to assess safety, ethics and public attitudes. We analyse video and transcripts of the meeting, and interviews with panellists to explore three themes: contesting scientific interpretation, the labour of alignment and resolution. We demonstrate how micro-interactions during the meeting, and the broader structure of the meeting itself, aligned with the UK sociotechnical imaginary of a permissive but scrutinising approach to human embryo regulation. We conclude that the event was one element of a larger process of review that together worked to render mitochondrial donation as knowable, ethical, desirable and sanctionable. [ABSTRACT FROM AUTHOR]

Background: The 2016 Patient-Oriented Strategy Encompassing IndividualizeD Oocyte Number (POSEIDON) criteria redefined the poor responders as low prognosis patients. The embryo transfer strategy for POSEIDON patients remained to be addressed. This study aimed to investigate the optimized number of embryos to transfer for unexpected low-prognosis patients (POSEIDON Group 1 and Group 2) with blastocyst transfer in their first frozen cycle. Methods: A retrospective cohort study of 2970 patients who underwent frozen-thawed embryo transfer (FET) between January 2018 and December 2021. Patients from POSEIDON Group 1 (N = 219) and Group 2 (N = 135) who underwent blastocyst transfer in their first FET cycles were included and divided into the elective single embryo transfer (eSET) group and the double embryo transfer (DET) group. Results: For POSEIDON Group 1, the live birth rate per embryo transfer of the DET group was slightly higher than the eSET group (52.17% vs 46.15%, OR 0.786, 95% CI 0.462–1.337, P = 0.374; adjusted OR (aOR) 0.622, 95% CI 0.340–1.140, P = 0.124), while a significant increase of 20.00% in the multiple birth rate was shown. For Group 2, higher live birth rates were observed in the DET group compared to the eSET group (38.46% vs 20.48%, OR 0.412, 95% CI 0.190–0.892, P = 0.024; aOR 0.358, 95% CI 0.155–0.828, P = 0.016). The difference in the multiple birth rate was 20.00% without statistical significance. Univariate and multivariate analyses revealed that age (OR 0.759, 95% CI.624–0.922, P = 0.006 and OR 0.751, 95% CI 0.605–0.932, P = 0.009) and the number of transferred embryos (OR 0.412, 95% CI 0.190–0.892, P = 0.024 and OR 0.367, 95% CI 0.161–0.840, P = 0.018) were significant variables for the live birth rate in POSEIDON Group 2. Conclusions: The findings in the present study showed that eSET was preferred in the first frozen cycle for POSEIDON Group 1 to avoid unnecessary risks. Double embryo transfer strategy could be considered to improve the success rate for POSEIDON Group 2 with caution. Further stratification by age is needed for a more scientific discussion about the embryo transfer strategy for POSEIDON patients. [ABSTRACT FROM AUTHOR]

Whether single-cell RNA-sequencing (scRNA-seq) captures the same biological information as single-nucleus RNA-sequencing (snRNA-seq) remains uncertain and likely to be context-dependent. Herein, a head-to-head comparison was performed in matched normal-adenocarcinoma human lung samples to assess biological insights derived from scRNA-seq versus snRNA-seq and better understand the cellular transition that occurs from normal to tumoral tissue. Here, the transcriptome of 160,621 cells/nuclei was obtained. In non-tumor lung, cell type proportions varied widely between scRNA-seq and snRNA-seq with a predominance of immune cells in the former (81.5%) and epithelial cells (69.9%) in the later. Similar results were observed in adenocarcinomas, in addition to an overall increase in cell type heterogeneity and a greater prevalence of copy number variants in cells of epithelial origin, which suggests malignant assignment. The cell type transition that occurs from normal lung tissue to adenocarcinoma was not always concordant whether cells or nuclei were examined. As expected, large differential expression of the whole-cell and nuclear transcriptome was observed, but cell-type specific changes of paired normal and tumor lung samples revealed a set of common genes in the cells and nuclei involved in cancer-related pathways. In addition, we showed that the ligand-receptor interactome landscape of lung adenocarcinoma was largely different whether cells or nuclei were evaluated. Immune cell depletion in fresh specimens partly mitigated the difference in cell type composition observed between cells and nuclei. However, the extra manipulations affected cell viability and amplified the transcriptional signatures associated with stress responses. In conclusion, research applications focussing on mapping the immune landscape of lung adenocarcinoma benefit from scRNA-seq in fresh samples, whereas snRNA-seq of frozen samples provide a low-cost alternative to profile more epithelial and cancer cells, and yield cell type proportions that more closely match tissue content. Author summary: Single-cell transcriptomic datasets provide unprecedented opportunities to disentangle the complex tissue microenvironment and cellular origin of cancer. Data are scarce regarding the pros and cons of single-cell RNA sequencing (scRNA-seq) of freshly explanted human tissues over single-nuclei sequencing (snRNA-seq) from the same archived frozen tissues. Lung adenocarcinoma represents a medically valuable case study to compare the biological signal recovered through cells and nuclei sequencing. Here, we sequenced the transcriptome of 160,621 cells/nuclei in paired normal-adenocarcinoma lung samples. Cell type proportions varied widely between scRNA-seq and snRNA-seq with a predominance of immune cells in the former and epithelial cells in the later. Adenocarcinomas were characterized by an increase in cell type heterogeneity and a greater prevalence of malignant epithelial cells in both scRNA-seq and snRNA-seq. The cellular and gene expression transition that occur from normal lung to adenocarcinoma showed common and discordant biological insights whether cells or nuclei were examined. Research applications focussing on mapping the immune landscape of lung cancer benefit from scRNA-seq in fresh samples, whereas snRNA-seq of the same frozen samples provide a low-cost and more flexible alternative to profile more epithelial and cancer cells, and yield cell type proportions that more closely match tissue content. [ABSTRACT FROM AUTHOR]

Spermatozoa cryopreservation has been practiced for decades and is a very useful technique for long-term preservation of sperm fertility. The capability for semen cryopreservation varies across species, seasons, latitudes, and even for different ejaculates from the same animal. This article summarizes research results on sperm cryotolerance biomarkers in several species, focusing on three areas: spermatozoa cryotolerance biomarkers, seminal plasma proteins cryotolerance biomarkers, and other cryotolerance biomarkers. We discovered that sperm cryoresistance biomarkers are primarily related to sperm plasma membrane stability, the presence of antioxidant substances in sperm or seminal plasma, sperm cell energy metabolism, water and small molecule transport channels in the sperm plasma membrane, and antistress substances in sperm or seminal plasma. The research conducted using diverse livestock models can be employed to enhance the basic and applied reproduction of other mammals through the study of sperm cryotolerance biomarkers, as well as the substantial similarities between livestock and other organisms, including endangered species. [ABSTRACT FROM AUTHOR]

Objective: The objective was to examine the association between poor ovarian response to gonadotropin stimulation for in vitro fertilization (IVF) and adverse perinatal outcomes in singleton gestations in young patients. Methods: This was a retrospective cohort study including women aged 17–39 who underwent fresh embryo transfer and delivered a singleton neonate at a single center (pre-implantation genetic testing excluded) (2007–2022). Patients were classified as one of the following categories: poor responders—daily follicle-stimulating hormone (FSH) ≥ 150 IU yielding ≤ 3 retrieved oocytes; normal responders—4–15 oocytes; and high responders with ≥16 oocytes. The primary outcome was a composite of pre-eclampsia (mild or severe), small-for-gestational-age, gestational diabetes mellitus, and preterm birth (<37 weeks). We compared maternal and neonatal outcomes between the three groups. Multivariable logistic regression was used to control for confounders. Results: Overall, 507 women met the inclusion criteria. Of them, there were 44 (8.68%) poor responders, 342 (67.46%) normal responders, and 121 (23.87%) high responders. Poor responders, compared to normal and high responders, were characterized by a higher maternal age (34.64 ± 4.01 vs. 31.4 ± 5.04 vs. 30.01 ± 4.93, p < 0.001, respectively) and total FSH dosage (3028.41 ± 1792.05 IU vs. 2375.11 ± 1394.05 IU vs. 1869.31 ± 1089.63 IU, p < 0.001). The perinatal outcomes examined, including cesarean delivery (CD) rate and the composite outcome, were comparable between groups. Using multivariable logistic regression and adjusting for ovarian response group, maternal age, nulliparity, and estradiol level and endometrial thickness before ovulation triggering, poor response was not associated with CD rate or the composite outcome, with maternal age associated with CD (p = 0.005), and nulliparity with the composite outcome (p = 0.007). Similar results were obtained when comparing poor responders to each other group separately or to all other responders. Conclusions: Poor ovarian response is not associated with increased adverse maternal or neonatal outcomes. [ABSTRACT FROM AUTHOR]

The role of cytoplasmic fragmentation in human embryo development and reproductive potential is widely recognized, albeit without standard definition nor agreed upon implication. While fragmentation is best understood to be a natural process across species, the origin of fragmentation remains incompletely understood and likely multifactorial. Several factors including embryo culture condition, gamete quality, aneuploidy, and abnormal cytokinesis seem to have important role in the etiology of cytoplasmic fragmentation. Fragmentation reduces the volume of cytoplasm and depletes embryo of essential organelles and regulatory proteins, compromising the developmental potential of the embryo. While it has been shown that degree of fragmentation and embryo implantation potential are inversely proportional, the degree, pattern, and distribution of fragmentation as it relates to pregnancy outcome is debated in the literature. This review highlights some of the challenges in analysis of fragmentation, while revealing trends in our evolving knowledge of how fragmentation may relate to functional development of the human embryos, implantation, and pregnancy outcome. [ABSTRACT FROM AUTHOR]

BACKGROUND: Unexplained infertility is associated with a higher abortion rate and lower fertilization rate, implantation rate, clinical pregnancy rate and cumulative live birth rate. It is urgent to establish a clinical prediction model related to infertility of unknown cause to solve the problems of clinical prognosis and individualized medical services, and finally achieve the purpose of increasing the cumulative live birth rate of patients with infertility of unknown cause. OBJECTIVE: To construct and verify the prediction model of high-quality blastocyst formation in patients with unexplained infertility during in vitro fertilization. METHODS: A total of 419 patients with unknown infertility who underwent in vitro fertilization in the Assisted Reproduction Department of Changzhou Maternal and Child Health Care Hospital from March 2017 to June 2022 were retrospectively analyzed, including 317 patients with high-quality blastocysts and 102 patients without high-quality blastocysts. A prediction model was established and used as the model group. The model group was sampled 1 000 times by the Bootstrap method as the validation group. Firstly, the univariate analysis was used to screen the influencing factors of high-quality blastocyst formation of unknown infertility, and the best matching factors were selected by the least absolute shrinkage and selection operator (LASSO) algorithm. Multiple factors were included in the progressive Logistic regression to find out the independent influencing factors and draw a column graph. Finally, the subject working curve, calibration curve, clinical decision curve and clinical impact curve were used to verify the differentiation and accuracy of the prediction model as well as the clinical application efficiency. RESULTS AND CONCLUSION: (1) Univariate analysis of the factors influencing the formation of high-quality blastocyst of unknown infertility were age, insemination method, antimullerian hormone level, basal follicle-stimulating hormone level, basal luteinizing hormone level, human chorionic gonadotropin injection day follicle-stimulating hormone level, human chorionic gonadotropin day estradiol level, progesterone level on human chorionic gonadotropin day, the number of high-quality cleavage embryo (day 3) and the number of blastocyst formation (P < 0.05). (2) The best matching factors further screened by LASSO regression were age, insemination method, antimullerian hormone level, basal luteinizing hormone level, human chorionic gonadotropin injection day follicle-stimulating hormone level, human chorionic gonadotropin day estradiol level, the number of high-quality cleavage embryo (day 3) and the number of blastocyst formation (P < 0.05). Multifactor stepwise Logistic regression results showed that independent influencing factors on the formation of high-quality blastocysts for unexplained infertility were age, insemination method, antimullerian hormone level, the number of high-quality cleavage embryo (day 3), and the number of blastocyst formation. (3) Receiver operating characteristic curve exhibited that the area under the curve was 0.880(0.834, 0.926) in the model group and 0.889(0.859, 0.918) in the validation group. It showed that the prediction model had good differentiation. The average absolute error of the calibration curve was 0.036, indicating that the model had good accuracy. The Hosmer-Lemeshow test showed that there was no statistical difference between the prediction probability of blastocyst formation and the actual probability of blastocyst formation (P > 0.05). The clinical decision curve and clinical impact curve showed that the model group and the validation group had the maximum clinical net benefit when the threshold probability value was (0.16-0.96) and (0.08-0.93), respectively, and had better clinical application efficacy within the threshold probability range. These findings concluded that age, insemination method, antimullerian hormone, the number of highquality cleavage embryos (day 3), and the number of blastocyst formation were independent factors influencing the formation of the fine blastocyst in patients with unexplained infertility. The clinical prediction model constructed by these factors has good clinical prediction value and clinical application efficiency and can provide a basis for clinical prognosis and intervention as well as the formulation of individual medical programs. [ABSTRACT FROM AUTHOR]

Mammalian development commences with the zygote, which can differentiate into both embryonic and extraembryonic tissues, a capability known as totipotency. Only the zygote and embryos around zygotic genome activation (ZGA) (two‐cell embryo stage in mice and eight‐cell embryo in humans) are totipotent cells. Epigenetic modifications undergo extremely extensive changes during the acquisition of totipotency and subsequent development of differentiation. However, the underlying molecular mechanisms remain elusive. Recently, the discovery of mouse two‐cell embryo‐like cells, human eight‐cell embryo‐like cells, extended pluripotent stem cells and totipotent‐like stem cells with extra‐embryonic developmental potential has greatly expanded our understanding of totipotency. Experiments with these in vitro models have led to insights into epigenetic changes in the reprogramming of pluri‐to‐totipotency, which have informed the exploration of preimplantation development. In this review, we highlight the recent findings in understanding the mechanisms of epigenetic remodeling during totipotency capture, including RNA splicing, DNA methylation, chromatin configuration, histone modifications, and nuclear organization. [ABSTRACT FROM AUTHOR]

Objective: To propose a new classification system (Urman‐Vitale Classification System) for intrauterine adhesions (IUAs) and to evaluate anatomical and fertility outcomes after hysteroscopic adhesiolysis accordingly. Methods: A retrospective analysis of consecutive patients treated over 11 years by a single operator in a tertiary care hospital. Women with sonographic suspicion of IUAs were scheduled for hysterosalpingography (HSG) and hysteroscopy for confirmation and treatment. IUAs were divided into five classes according to symptoms, ultrasound, HSG findings, and postsurgical hysteroscopic appearance. Hysteroscopic adhesiolysis was performed using a bipolar cutting electrode in an office setting. Evaluated outcomes were restoration of the uterine cavity, clinical pregnancy, pregnancy loss, and live birth rates. Results: A total of 227 patients (479 procedures) were included. Mean number of hysteroscopies increased in frequency with class of adhesions from Class 1 to Class 5 (1.0 ± 0.2 vs 2.3 ± 0.5; P = 0.001). Full restoration of the cavity was achieved in 100% of patients with Class 1 compared with 18.5% for Class 5 (43/43 vs 5/27; P = 0.001). Clinical pregnancy (Class 1 vs Class 4: P = 0.034; 1 vs 5: P = 0.006; 2 vs 5: P = 0.024) and live birth (Class 1 vs Class 4: P = 0.001; 1 vs 5: P = 0.006; 2 vs 4: P = 0.007; 2 vs 5: P = 0.0208) rates decreased with increasing severity of IUAs. Pregnancy loss rate was related to IUA severity (Class 1 vs Class 4: P = 0.012; 1 vs 5: P = 0.003: 2 vs 4: P = 0.014; 2 vs 5: P = 0.021). Conclusion: A classification based on symptoms, imaging findings, and postsurgical macroscopic appearance of the uterine cavity could be useful in predicting prognosis and fertility in women with IUAs. Synopsis: A new classification for intrauterine adhesions based on symptoms, imaging, and hysteroscopic appearance of the uterine cavity could simplify postsurgical prognosis and fertility. [ABSTRACT FROM AUTHOR]

In vitro fertilization (IVF) is an efficacious form of aided reproduction to deal with infertility. Human embryos are taken from the body, and these are kept in a supervised laboratory atmosphere during the IVF technique until they exhibit blastocyst properties. A human expert manually analyzes the morphometric properties of the blastocyst and its compartments to predict viability through manual microscopic evaluation. A few deep learning-based approaches deal with this task via semantic segmentation, but they are inaccurate and use expensive architecture. To automatically detect the human blastocyst compartments, we propose a parallel stream fusion network (PSF-Net) that performs the semantic segmentation of embryo microscopic images with inexpensive shallow architecture. The PSF-Net has a shallow architecture that combines the benefits of feature aggregation through depth-wise concatenation and element-wise summation, which helps the network to provide accurate detection using 0.7 million trainable parameters only. In addition, we compute fractal dimension estimation for all compartments of the blastocyst, providing medical experts with significant information regarding the distributional characteristics of blastocyst compartments. An open dataset of microscopic images of the human embryo is used to evaluate the proposed approach. The proposed method also demonstrates promising segmentation performance for all compartments of the blastocyst compared with state-of-the-art methods, achieving a mean Jaccard index (MJI) of 87.69%. The effectiveness of PSF-Net architecture is also confirmed with the ablation studies. [ABSTRACT FROM AUTHOR]

Understanding the processes and mechanisms underlying early human embryo development has become an increasingly active and important area of research. It has potential for insights into important clinical issues such as early pregnancy loss, origins of congenital anomalies and developmental origins of adult disease, as well as fundamental insights into human biology. Improved culture systems for preimplantation embryos, combined with the new tools of single cell genomics and live imaging, are providing new insights into the similarities and differences between human and mouse development. However, access to human embryo material is still restricted and extended culture of early embryos has regulatory and ethical concerns. Stem cell-derived models of different phases of human development can potentially overcome these limitations and provide a scalable source of material to explore the early postimplantation stages of human development. To date, such models are clearly incomplete replicas of normal development but future technological improvements can be envisaged. The ethical and regulatory environment for such studies remains to be fully resolved. • Research on human embryo development has biological and clinical applications. • Direct analysis of human embryo material can be informative, but access is limited. • Stem cell-derived embryo models provide accessible, scalable alternatives. • Ethical concerns with stem cell models will require ongoing discussion and debate. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to provide a detailed analysis of clinical and laboratory factors associated with skewed secondary sex ratio (SSR) after ART. Method: Retrospective cohort study of embryos resulting in live births, from frozen and fresh single blastocyst transfers. Embryos were cultured in either G-TL (n = 686) or Sage media (n = 685). Data was analyzed using a multivariate logistic regression model and a mixed model analysis. Results: Significantly more male singletons were born after culture in Sage media compared to G-TL media (odds ratio (OR) 1.34, 95% CI (1.05, 1.70), P = 0.02). Inner cell mass grade B vs A (OR 1.36 95% CI (1.05, 1.76), P = 0.02) and one previous embryo transfer (OR 1.49, 95% CI (1.03, 2.16), P = 0.03) were associated with a significantly higher probability of male child at birth. Factors associated with a reduced probability of male child were expansion grade 3 vs 5 (OR 0.66, 95% CI (10.45, 0.96), P = 0.03) and trophectoderm grade B vs A (OR 0.57, 95% CI (0.44, 0.74), P = 0.00). Male embryos developed significantly faster in Sage media compared to G-TL media for the stages of blastocyst (− 1.12 h, 95% CI (− 2.12, − 0.12)), expanded blastocyst (− 1.35 h, 95% CI (− 2.34, − 0.35)), and hatched blastocyst (− 1.75 h, 95% CI (− 2.99, − 0.52)). Conclusion: More male children were born after culture in Sage media compared to G-TL media. Male embryo development was affected by culture media. Our observations suggest that culture media impact male embryo quality selectively, thus potentially favoring the selection of male embryos. [ABSTRACT FROM AUTHOR]

The possibility of embryo cryopreservation is important for applying the genome resource banking (GRB) concept to those mammalian species that exhibit embryonal diapause in their early development. Odc1 encodes ODC1, which is a key enzyme in polyamine synthesis. RhoA is an essential part of Rho/ROCK system. Both Odc1 and RhoA play an important role in preimplantation embryo development. Studying these systems in mammalian species with obligate or experimentally designed embryonic diapause may provide insight into the molecular machinery underlying embryo dormancy and re‐activation. The effect of cryopreservation procedures on the expression of the Odc1 and RhoA in diapausing embryos has not been properly studied yet. The purpose of this work is to address the possibility of cryopreservation diapausing embryos and to estimate the expression of the Odc1 and RhoA genes in diapausing and non‐diapausing embryos before and after freeze–thaw procedures using ovariectomized progesterone treated mice as a model. Both diapausing and non‐diapausing in vivo‐derived embryos continued their development in vitro after freezing–thawing as evidenced by blastocoel re‐expansion. Although cryopreservation dramatically decreased the expression of the Odc1 and RhoA genes in non‐diapausing embryos, no such effects have been observed in diapausing embryos where these genes were already at the low level before freeze–thaw procedures. Future studies may attempt to facilitate the re‐activation of diapausing embryos, for example frozen–thawed ones, specifically targeting Odc1 or Rho/ROCK system. [ABSTRACT FROM AUTHOR]

STUDY QUESTION How does ovarian stimulation (OS), which is used to mature multiple oocytes for ART procedures, impact the principal cellular compartments and transcriptome of the human endometrium in the periovulatory and mid-secretory phases? SUMMARY ANSWER During the mid-secretory window of implantation, OS alters the abundance of endometrial immune cells, whereas during the periovulatory period, OS substantially changes the endometrial transcriptome and impacts both endometrial glandular and immune cells. WHAT IS KNOWN ALREADY Pregnancies conceived in an OS cycle are at risk of complications reflective of abnormal placentation and placental function. OS can alter endometrial gene expression and immune cell populations. How OS impacts the glandular, stromal, immune, and vascular compartments of the endometrium, in the periovulatory period as compared to the window of implantation, is unknown. STUDY DESIGN, SIZE, DURATION This prospective cohort study carried out between 2020 and 2022 included 25 subjects undergoing OS and 25 subjects in natural menstrual cycles. Endometrial biopsies were performed in the proliferative, periovulatory, and mid-secretory phases. PARTICIPANTS/MATERIALS, SETTING, METHODS Blood samples were processed to determine serum estradiol and progesterone levels. Both the endometrial transcriptome and the principal cellular compartments of the endometrium, including glands, stroma, immune, and vasculature, were evaluated by examining endometrial dating, differential gene expression, protein expression, cell populations, and the three-dimensional structure in endometrial tissue. Mann–Whitney U tests, unpaired t -tests or one-way ANOVA and pairwise multiple comparison tests were used to statistically evaluate differences. MAIN RESULTS AND THE ROLE OF CHANCE In the periovulatory period, OS induced high levels of differential gene expression, glandular-stromal dyssynchrony, and an increase in both glandular epithelial volume and the frequency of endometrial monocytes/macrophages. In the window of implantation during the mid-secretory phase, OS induced changes in endometrial immune cells, with a greater frequency of B cells and a lower frequency of CD4 effector T cells. LARGE SCALE DATA The data underlying this article have been uploaded to the Genome Expression Omnibus/National Center for Biotechnology Information with accession number GSE220044. LIMITATIONS, REASONS FOR CAUTION A limited number of subjects were included in this study, although the subjects within each group, natural cycle or OS, were homogenous in their clinical characteristics. The number of subjects utilized was sufficient to identify significant differences; however, with a larger number of subjects and additional power, we may detect additional differences. Another limitation of the study is that proliferative phase biopsies were collected in natural cycles, but not in OS cycles. Given that the OS cycle subjects did not have known endometrial factor infertility, and the comparisons involved subjects who had a similar and robust response to stimulation, the findings are generalizable to women with a normal response to OS. WIDER IMPLICATIONS OF THE FINDINGS OS substantially altered the periovulatory phase endometrium, with fewer transcriptomic and cell type-specific changes in the mid-secretory phase. Our findings show that after OS, the endometrial microenvironment in the window of implantation possesses many more similarities to that of a natural cycle than does the periovulatory endometrium. Further investigation of the immune compartment and the functional significance of this cellular compartment under OS conditions is warranted. STUDY FUNDING/COMPETING INTERESTS Research reported in this publication was supported by the National Institute of Allergy and Infectious Diseases (R01AI148695 to A.M.B. and N.C.D.), Eunice Kennedy Shriver National Institute of Child Health and Human Development (R01HD109152 to R.A.), and the March of Dimes (5-FY20-209 to R.A.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health or March of Dimes. All authors declare no conflict of interest. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Is there a cumulative toxicity of disposables used in IVF procedures? SUMMARY ANSWER A toxicity may be detected when consumables are used cumulatively, while no toxicity is detected when the same consumables are used and tested individually. WHAT IS KNOWN ALREADY Many components of items used in IVF laboratories may impair human embryonic development. Consequently, it is necessary to screen all reagents and materials which could be in contact with gametes and embryos. Toxicity tests, such as the mouse embryo assay and the human sperm motility assay (HSMA), are used by manufacturers as quality control tools to demonstrate the safety of their products. This evaluation is currently individually performed for each single consumable. However, during an IVF cycle, several devices are used sequentially, potentially creating a cumulative exposure to chemical contaminants, which could not be detected for individually tested consumables. STUDY DESIGN, SIZE, DURATION The objective of this observational study conducted from March 2021 to October 2022 was to evaluate with the HSMA methodology if there was a cumulative toxicity when several disposables are sequentially used. Fourteen categories of consumables currently used in routine IVF procedures were studied, which included devices used for sperm and oocyte collection (cups, condoms, and oocyte aspiration needles), manipulation (flasks, tubes, tips, pipettes, embryo transfer catheters, syringes, and gloves), culture (dishes), and storage (straws). PARTICIPANTS/MATERIALS, SETTING, METHODS After obtaining patient consent, the surplus semen assessed as having normal parameters according to the World Health Organization 2010 criteria were used to perform the HSMAs. First, each consumable was tested individually. Then, associations of three, four, and five consumables, previously validated as non-toxic when tested individually, were analyzed. HSMAs were conducted three times to ensure reproducibility, with a defined toxicity threshold of a sperm motility index (SMI) below 0.85 in at least two of three tests. MAIN RESULTS AND THE ROLE OF CHANCE Thirty-six references of disposables were first individually tested across 53 lots. Forty-nine (92%) demonstrated compliance. However, four (8%) devices revealed toxicity: one lot of 1 ml syringes, two lots of sperm cups, and one lot of 25 cm2 flasks. These four references were excluded from the IVF routine procedures. A total of 48 combinations of consumables were assessed, involving 41 lots from 32 references that were previously individually tested. Among the evaluated combinations, 17 out of 48 (35%) associations exhibited toxicity with a SMI below 0.85 for two of the three tests (n = 8) or all the three tests (n = 9). Notably, three out of 17 (18%) of the three-consumable associations, five out of 16 (31%) of the four-consumable associations, and nine out of 15 (60%) of the five-consumable associations were found not compliant. The toxicity did not originate from a single consumable, because only consumables that were individually pre-validated as non-toxic were included in the combinations, but the toxicity had a cumulative origin. The risk of cumulative toxicity increased with the number of consumables included in the association (Cochran–Mantel–Haenszel statistic, P  = 0.013). LIMITATIONS, REASONS FOR CAUTION The high proportion of non-compliant combinations of disposables can be attributed directly to the extreme rigorous extraction conditions employed during the tests, which could deviate from the conditions encountered in routine clinical use. Also, the methodology employed in the HSMAs (e.g. toxicity extraction duration, sperm concentrations, and protein supplementation of the medium) can influence the sensitivity of the tests. WIDER IMPLICATIONS OF THE FINDINGS This study highlights the significance of performing toxicity testing on devices before introducing them into clinical practice. Disposables should be tested individually to detect immediate toxicities and also in combination. Our results advocate rationalizing the number of consumables used in each IVF procedure and re-evaluating the use of glass consumables. STUDY FUNDING/COMPETING INTEREST(S) This study received fundings from GCS Ramsay Santé pour l'Enseignement et la Recherche (Paris, France) and the Centre de Biologie Médicale BIOGROUP (Le Chesnay-Rocquencourt, France). The authors declare that they have no conflict of interest that could be perceived as prejudicing the impartiality of the reported research. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

Background: Current approaches to profile the single-cell transcriptomics of human pancreatic endocrine cells almost exclusively rely on freshly isolated islets. However, human islets are limited in availability. Furthermore, the extensive processing steps during islet isolation and subsequent single cell dissolution might alter gene expressions. In this work, we report the development of a single-nucleus RNA sequencing (snRNA-seq) approach with targeted islet cell enrichment for endocrine-population focused transcriptomic profiling using frozen archival pancreatic tissues without islet isolation. Results: We cross-compared five nuclei isolation protocols and selected the citric acid method as the best strategy to isolate nuclei with high RNA integrity and low cytoplasmic contamination from frozen archival human pancreata. We innovated fluorescence-activated nuclei sorting based on the positive signal of NKX2-2 antibody to enrich nuclei of the endocrine population from the entire nuclei pool of the pancreas. Our sample preparation procedure generated high-quality single-nucleus gene-expression libraries while preserving the endocrine population diversity. In comparison with single-cell RNA sequencing (scRNA-seq) library generated with live cells from freshly isolated human islets, the snRNA-seq library displayed comparable endocrine cellular composition and cell type signature gene expression. However, between these two types of libraries, differential enrichments of transcripts belonging to different functional classes could be observed. Conclusions: Our work fills a technological gap and helps to unleash frozen archival pancreatic tissues for molecular profiling targeting the endocrine population. This study opens doors to retrospective mappings of endocrine cell dynamics in pancreatic tissues of complex histopathology. We expect that our protocol is applicable to enrich nuclei for transcriptomics studies from various populations in different types of frozen archival tissues. [ABSTRACT FROM AUTHOR]

One of the parameters potentially affecting the in vitro growth of preimplantation embryos is the oxygen concentration in the culture environment. An increased oxygen concentration causes the generation of ROS which in turn can cause damage to the cells and seriously disrupt the embryonic development. Previous studies have assessed oxygen concentrations in the fallopian tubes of several mammals of between 5 and 8%, while the oxygen levels in the uterus were found to be even lower; similar measurements have been confirmed in humans. In addition, studies in mammalian embryos showed that low oxygen concentrations improve embryo development. Multiple studies on the effect of the oxygen concentration on human embryos have been conducted so far with diverse methodologies and objectives. Data from these have been included in three meta-analyses. All meta-analyses indicate the potential benefit in favor of a low oxygen concentration, though data are considered to be of a low methodological quality and further studies are considered necessary. However, based on the existing evidence, it is suggested that a low oxygen concentration should be adopted in the routine of the IVF laboratory, especially in the case of blastocyst culture. [ABSTRACT FROM AUTHOR]

During maternal‐to‐zygotic transition (MZT) in the embryo, mRNA undergoes complex post‐transcriptional regulatory processes. However, it is unclear whether and how alternative splicing plays a functional role in MZT. By analyzing transcriptome changes in mouse and human early embryos, dynamic changes in alternative splicing during MZT are observed and a previously unnoticed process of zygotic splicing activation (ZSA) following embryonic transcriptional activation is described. As the underlying mechanism of RNA splicing, splicing factors undergo dramatic maternal‐to‐zygotic conversion. This conversion relies on the key maternal factors BTG4 and PABPN1L and is zygotic‐transcription‐dependent. CDK11‐dependent phosphorylation of the key splicing factor, SF3B1, and its aggregation with SRSF2 in the subnuclear domains of 2‐cell embryos are prerequisites for ZSA. Isoforms generated by erroneous splicing, such as full‐length Dppa4, hinder normal embryonic development. Moreover, alternative splicing regulates the conversion of early embryonic blastomeres from totipotency to pluripotency, thereby affecting embryonic lineage differentiation. ZSA is an essential post‐transcriptional process of MZT and has physiological significance in generating new life. In addition to transcriptional activation, appropriate expression of transcript isoforms is also necessary for preimplantation embryonic development. [ABSTRACT FROM AUTHOR]

The urinary collecting system (UCS) consists of organized ducts that collect urine from the nephrons and transport it to the ureter and bladder. Understanding the histogenesis of the UCS is critical. Thirty human embryos between the Carnegie stages (CS) 18 and 23 were selected from the Congenital Anomaly Research Center, Kyoto, Japan. Epithelia of the UCS, ureter, and bladder of each sample were randomly selected. Histological findings of the epithelia were analyzed according to the following criteria: type of epithelium, presence or absence of glycogen, percentage of migrated nuclei, percentage of cells in mitosis, and the surrounding mesenchyme. A thickened epithelium lining a narrow luminal cavity was observed in the pre-expanded pelvic specimens at CS18-CS23. At CS23, after pelvic expansion, the UCS showed a thin epithelium with a large luminal cavity mainly located on the early branches, whereas the epithelium covering the subsequent branches had medium thickness. Histological characteristics differed depending on the UCS part and sample stage. The degree of differentiation was evaluated, revealing that in CS18-CS23 pre-expanded pelvis specimens, the undifferentiated epithelium was found in the zeroth to third/fifth generation, whereas at CS23, after pelvic expansion, a differentiated epithelium covered the UCS zeroth to seventh generation. In a comparison of the urothelial epithelium between the UCS, ureter, and bladder, we found that urinary tract differentiation may be initiated in the bladder, followed by the ureter, UCS zeroth to seventh generations, and finally, UCS eighth to end generations. An understanding of the histogenesis of embryonic stage UCS can aid in the clinical management of congenital urinary tract defects and other diseases. [ABSTRACT FROM AUTHOR]

Mutually beneficial partnerships between genomics researchers and North American Indigenous Nations are rare yet becoming more common. Here, we present one such partnership that provides insight into the peopling of the Americas and furnishes another line of evidence that can be used to further treaty and Indigenous rights. We show that the genomics of sampled individuals from the Blackfoot Confederacy belong to a previously undescribed ancient lineage that diverged from other genomic lineages in the Americas in Late Pleistocene times. Using multiple complementary forms of knowledge, we provide a scenario for Blackfoot population history that fits with oral tradition and provides a plausible model for the evolutionary process of the peopling of the Americas. [ABSTRACT FROM AUTHOR]

O -GlcNAcylation is a dynamic modulator of signaling pathways, equal in magnitude to the widely studied phosphorylation. With the rapid development of tools for its detection at the single protein level, the O -GlcNAc modification rapidly emerged as a novel diagnostic and therapeutic target in human diseases. Yet, mapping the human O -GlcNAcome in various tissues is essential for generating relevant biomarkers. In this study, we used human banked tissue as a sample source to identify O -GlcNAcylated protein targets relevant to human diseases. Using human term placentas, we propose (1) a method to clean frozen banked tissue of blood proteins; (2) an optimized protocol for the enrichment of O -GlcNAcylated proteins using immunoaffinity purification; and (3) a bioinformatic workflow to identify the most promising O -GlcNAc targets. As a proof-of-concept, we used 45 mg of banked placental samples from two pregnancies to generate intracellular protein extracts depleted of blood protein. Then, antibody-based O -GlcNAc enrichment on denatured samples yielded over 2000 unique HexNAc PSMs and 900 unique sites using 300 μg of protein lysate. Due to efficient sample cleanup, we also captured 82 HexNAc proteins with high placental expression. Finally, we provide a bioinformatic tool (CytOVS) to sort the HexNAc proteins based on their cellular localization and extract the most promising O -GlcNAc targets to explore further. To conclude, we provide a simple 3-step workflow to generate a manageable list of O -GlcNAc proteins from human tissue and improve our understanding of O-GlcNAcylation's role in health and diseases. [ABSTRACT FROM AUTHOR]

Despite serum progesterone being a widely accepted method for luteal phase support during embryo transfer cycles, debates persist regarding the optimal strategy for guiding clinical decisions on progesterone dosages to maximize reproductive outcomes. This retrospective study explored the utility of microRNA (miRNA) biomarkers in guiding personalized progesterone dosage adjustments for frozen embryo transfer (FET) cycles in 22 in vitro fertilization (IVF) patients undergoing hormone replacement therapy. Utilizing MIRA, an miRNA-based endometrial receptivity test, we analyzed patients' miRNA expression profiles before and after progesterone dosage adjustments to determine suitable dosages and assess endometrial status. Despite patients receiving identical progesterone dosages, variations in miRNA profiles were observed in the initial cycle, and all patients presented a displaced window of implantation. Following dosage adjustments based on their miRNA profiles, 91% of patients successfully transitioned their endometrium towards the receptive stages. However, two patients continued to exhibit persistent displaced receptivity despite the adjustments. Given the evident variation in endometrial status and serum progesterone levels among individuals, analyzing miRNA expression profiles may address the challenge of inter-personal variation in serum progesterone levels, to deliver more personalized dosage adjustments and facilitate personalized luteal phase support in IVF. [ABSTRACT FROM AUTHOR]

The use of human stem-cell-derived embryo models in biomedical research has recently sparked intense bioethical debates. In this article, we delve into the ethical complexities surrounding these models and advocate for a deeper exploration of their biological ontology to discuss their bioethical normativity. We examine the ethical considerations arising from the implementation of these models, emphasizing varying viewpoints on their ethical standing and the ethical obligations associated with their development and utilization. We contend that a nuanced comprehension of their biological ontology is crucial for navigating these ethical quandaries. Furthermore, we underscore the indispensability of interdisciplinary cooperation among bioethicists, biologists, and philosophers to unravel the complex interplay between biological ontology and the normative framework of bioethics. Moreover, this article introduces a novel combinatorial approach to resolve the ethical dilemma surrounding these models. We propose a distinction between models that closely emulate natural embryos, based on the status of synthetic embryos, and those capable of reproducing specific dimensions of embryonic development. Such differentiation allows for nuanced ethical considerations while harnessing the value of these models in scientific research, paving the way for a more comprehensive ethical framework in the context of evolving biotechnologies. [Display omitted] [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the role of serum progesterone (P4) on the day of embryo transfer (ET) when dydrogesterone (DYD) and micronized vaginal progesterone (MVP) are combined as luteal phase support (LPS) in a hormone replacement therapy (HRT) frozen ET (FET) cycles. Methods: Retrospective study, including single euploid HRT FET cycles with DYD and MVP as LPS and P4 measurement on ET day. Initially, patients with P4 levels < 10 ng/ml increased MVP to 400 mg/day; this "rescue" was abandoned later. Results: 560 cycles of 507 couples were included. In 275 women, serum P4 level was < 10 ng/ml on the ET day. Among those with low P4 levels, MVP dose remained unchanged in 65 women (11.6%) and was increased in 210 women (37.5%). Women with P4 levels ≥ 10 ng/ml continued LPS without modification. Overall pregnancy rates in these groups were 61.5% (40/65), 54.8% (115/210), and 48.4% (138/285), respectively (p = n.s.). Association of serum P4 levels with ongoing pregnancy rates was analyzed in women without any additional MVP regardless of serum P4 levels (n = 350); multivariable analysis (adjusted for age, BMI, embryo quality (EQ)) did not show a significant association of serum P4 levels with OPR (OR 0.96, 95% CI 0.90–1.02; p = 0.185). Using inverse probability treatment weights, regression analysis in the weighted sample showed no significant association between P4 treatment groups and OP. Compared to fair EQ, the transfer of good EQ increased (OR 1.61, 95% CI 1.22–2.15; p = 0.001) and the transfer of a poor EQ decreased the odds of OP (OR 0.73, 95% CI 0.55–0.97; p = 0.029). Conclusion: In HRT FET cycle, using LPS with 300 mg/day MVP and 30 mg/day DYD, it appears that serum P4 measurement and increase of MVP in patients with P4 < 10 ng/ml are not necessary. [ABSTRACT FROM AUTHOR]

Purpose: To explore whether letrozole improved outcomes in subsequent controlled ovarian hyperstimulation (COH) cycles. Methods: This was a retrospective repeated measures cohort study examining COH cycles. Patients were included if they underwent two cycles for unexplained infertility, male factor infertility, or planned oocyte/embryo cryopreservation. The first cycles for all patients implemented a non-letrozole, conventional gonadotropin protocol. Second cycles for the study group included letrozole (2.5–7.5 mg for 5 days) with no medication change to second cycles amongst controls. Our primary objective was to compare oocyte yield. Cohorts were then subdivided by pursuit of oocyte (OC) or embryo (IVF) cryopreservation. Secondary outcome amongst the OC subgroup was oocyte maturation index (metaphase II (MII)/total oocytes). Secondary outcomes amongst the IVF subgroup were normal fertilization rate (2-pronuclear zygotes (2PN)/oocytes exposed to sperm), blastocyst formation rate (blastocysts/2PNs), and embryo ploidy (%euploid and aneuploid). Results: Fifty-four cycles (n = 27) were included in letrozole and 108 cycles (n = 54) were included in control. Oocyte yield was higher in second cycles (p < 0.008) in the letrozole group but similar in second cycles (p = 0.26) amongst controls. Addition of letrozole did not impact MII index (p = 0.90); however, MII index improved in second cycles amongst controls (p < 0.001). Both groups had similar rates of normal fertilization (letrozole: p = 0.52; control: p = 0.61), blast formation (letrozole: p = 0.61; control: p = 0.84), euploid (letrozole: p = 0.29; control: p = 0.47), and aneuploid embryos (letrozole: p = 0.17; control: p = 0.78) between cycles. Conclusions: Despite improved oocyte yield, letrozole did not yield any difference in oocyte maturation or embryo outcomes. [ABSTRACT FROM AUTHOR]

Purpose: This prospective study investigates the correlation between vaginal microecology and pregnancy outcomes and explores their impact on endometrial microbiota composition during frozen embryo transfer (FET) cycles. Additionally, the impact of transvaginal Lactobacillus supplementation on reproductive outcomes in patients with previous failed cycles was assessed. Methods: A total of 379 patients undergoing FET at a reproductive medicine center were categorized into clinical pregnancy (CP), miscarriage (MISC), and non-pregnant (NP) groups. Vaginal specimens were collected for microecological evaluation prior to embryo transfer. Endometrial microbiota samples were obtained during embryo transfer for 16S rRNA gene sequencing analysis to assess endometrial microbiota composition. Vaginal microecological indicators, including pH, Lactobacillus dominance, and leukocyte esterase activity, were measured. Transvaginal Lactobacillus supplementation was investigated in 60 patients with previous failed cycles. Results: Vaginal microecology significantly correlated with pregnancy outcomes, with normal microecology associated with a higher clinical pregnancy rate. Vaginal pH and leukocyte esterase activity were significantly associated with clinical pregnancy. Furthermore, vaginal microecological differences significantly impacted endometrial microbiota composition. However, no significant differences were observed in endometrial microbiota composition among the CP, MISC, and NP groups. Notably, transvaginal Lactobacillus supplementation increased the clinical pregnancy rate without affecting the miscarriage rate. Conclusion: This study highlights that normal vaginal microecology, characterized by lower pH and leukocyte esterase negativity, is associated with a higher likelihood of clinical pregnancy following FET. Importantly, vaginal microecological differences influence endometrial microbiota composition. Moreover, transvaginal Lactobacillus supplementation appears promising in improving clinical pregnancy rates in patients with previous failed cycles. These findings contribute to a better understanding of the interplay between vaginal and endometrial microbiota and offer potential interventions to enhance reproductive success in assisted reproductive technologies. [ABSTRACT FROM AUTHOR]

Purpose: There is an unclear relationship between estradiol levels and fresh embryo transfer (ET) outcomes. We determined the relationship between estradiol on the day of trigger, in fresh ET cycles without premature progesterone elevation, and good birth outcomes (GBO). Methods: We identified autologous fresh ET cycles from 2015 to 2021 at multiple clinics in the USA. Patients with recurrent pregnancy loss, uterine factor, and elevated progesterone on the day of trigger (progesterone > 2 ng/mL or 3-day area under the curve > 4.5 ng/mL) were excluded. The primary outcome was GBO (singleton, term, live birth with appropriate weight). Log-binomial generalized estimating equations determined the likelihood of outcomes. Results: Of 17,608 fresh ET cycles, 5025 (29%) yielded GBO. Cycles with estradiol ≥ 4000 pg/mL had a greater likelihood of GBO compared to cycles < 1000 pg/mL (aRR = 1.32, 95% CI 1.13–1.54). Pairwise comparisons of estradiol between < 1000 pg/mL versus 1000–1999 pg/mL and 1000–1999 pg/mL versus 2000–2999 pg/mL revealed a higher likelihood of GBO with higher estradiol (aRR 0.83, 95% CI 0.73–0.95; aRR 0.91, 95% CI 0.85–0.97, respectively). Comparisons amongst more elevated estradiol levels revealed that the likelihood of GBO remained similar between groups (2000–2999 pg/mL versus 3000–3999 pg/mL, aRR 1.04, 95% CI 0.97–1.11; 3000–3999 pg/mL versus ≥ 4000 pg/mL, aRR 0.96, 95% CI 0.9–1.04). Conclusion: In fresh ET cycles, higher estradiol levels were associated with an increased prevalence of GBO until estradiol 2000–2999 pg/mL, thereafter plateauing. In fresh ET candidates, elevated estradiol levels should not preclude eligibility though premature progesterone rise, and risk of ovarian hyperstimulation syndrome must still be considered. [ABSTRACT FROM AUTHOR]

Purpose: To assess the relation between number of inseminated oocytes and cumulative live birth rate (CLBR) in order to provide guidance for limiting the number of surplus blastocysts. Methods: The study was a retrospective, single-center cohort analysis of 1223 ART complete cycles. Cycles were stratified according to female age (≤ 34, 35–38, and 39–42 years) and number of inseminated oocytes (1–5, 6–10, and > 10). Inclusion criteria were indication for IVF/ICSI with own spermatozoa and blastocyst culture up to day 6 of all embryos. Results: In patients younger than 35 years, insemination of more than ten oocytes produced an increase in overall blastocyst number, CLBR (40.3%, 54.3%, and 75.8%, respectively, for each oocyte group) and surplus embryo rate (12.9%, 27.8%, and 49.7% of cases for each group). Instead, in the middle age group, the use of more than ten oocytes was solely associated with an increase in the rate of surplus embryos (1.25%, 21.33%, and 28.68% of cases after stratification for oocyte number). In older patients, neither CLBR (9.1%, 23.9%, and 24.7%, respectively) nor rate of surplus embryos (2.0%, 7.1%, and 13.4% of cases for each group) were higher in cycles with more than ten inseminated oocytes. Conclusion: In women up to 38 years, sustainable CLBR are achieved while limiting the number of inseminated oocytes and the resulting blastocysts remaining unused. Based on this notion, novel treatment strategies could pursue high outcome rates, while alleviating the problems derived from surplus stored embryos. [ABSTRACT FROM AUTHOR]

Background: There is currently no information on positional changes in the brachial nerve plexus during prenatal growth. The subclavian–axillary artery passing through the medianus nerve ansa is considered a good landmark for evaluating the height of the plexus. Materials and methods: We used histologic sections from 9 embryos and 17 fetuses (approximately 6–15 weeks of gestational age) to identify the height of the ansa by referring to the level of the rib and the glenohumeral joint. Results: The nerve ansa was usually (23 plexuses) observed at the level of the first and/or second ribs. However, it was sometimes observed above the first rib, at a distance equal to or more than an intercostal width (7 plexuses). In the latter group, the ansa was usually located below the glenohumeral joint. Thus, the joint was located higher than the first rib, although the upper extremities were in the anatomic position for all specimens. The left–right difference in the height of the plexus corresponded to or was less than the width of the first intercostal space. Despite the synchronized growth between the thorax and shoulder girdle, the brachial plexus showed a considerable variation in comparative height; the range corresponded to twice of an intercostal width. Whether the nerve plexus is located high or low is determined at an early developmental stage and is maintained during the later growth stages. Conclusion: The high-positioned plexus might cause nerve injury at delivery, followed by a glenohumeral joint deformity because of the fragility without fixation in the thorax. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Can the BlastAssist deep learning pipeline perform comparably to or outperform human experts and embryologists at measuring interpretable, clinically relevant features of human embryos in IVF? SUMMARY ANSWER The BlastAssist pipeline can measure a comprehensive set of interpretable features of human embryos and either outperform or perform comparably to embryologists and human experts in measuring these features, WHAT IS KNOWN ALREADY Some studies have applied deep learning and developed 'black-box' algorithms to predict embryo viability directly from microscope images and videos but these lack interpretability and generalizability. Other studies have developed deep learning networks to measure individual features of embryos but fail to conduct careful comparisons to embryologists' performance, which are fundamental to demonstrate the network's effectiveness. STUDY DESIGN, SIZE, DURATION We applied the BlastAssist pipeline to 67 043 973 images (32 939 embryos) recorded in the IVF lab from 2012 to 2017 in Tel Aviv Sourasky Medical Center. We first compared the pipeline measurements of individual images/embryos to manual measurements by human experts for sets of features, including: (i) fertilization status (n = 207 embryos), (ii) cell symmetry (n = 109 embryos), (iii) degree of fragmentation (n = 6664 images), and (iv) developmental timing (n = 21 036 images). We then conducted detailed comparisons between pipeline outputs and annotations made by embryologists during routine treatments for features, including: (i) fertilization status (n = 18 922 embryos), (ii) pronuclei (PN) fade time (n = 13 781 embryos), (iii) degree of fragmentation on Day 2 (n = 11 582 embryos), and (iv) time of blastulation (n = 3266 embryos). In addition, we compared the pipeline outputs to the implantation results of 723 single embryo transfer (SET) cycles, and to the live birth results of 3421 embryos transferred in 1801 cycles. PARTICIPANTS/MATERIALS, SETTING, METHODS In addition to EmbryoScope™ image data, manual embryo grading and annotations, and electronic health record (EHR) data on treatment outcomes were also included. We integrated the deep learning networks we developed for individual features to construct the BlastAssist pipeline. Pearson's χ 2 test was used to evaluate the statistical independence of individual features and implantation success. Bayesian statistics was used to evaluate the association of the probability of an embryo resulting in live birth to BlastAssist inputs. MAIN RESULTS AND THE ROLE OF CHANCE The BlastAssist pipeline integrates five deep learning networks and measures comprehensive, interpretable, and quantitative features in clinical IVF. The pipeline performs similarly or better than manual measurements. For fertilization status, the network performs with very good parameters of specificity and sensitivity (area under the receiver operating characteristics (AUROC) 0.84–0.94). For symmetry score, the pipeline performs comparably to the human expert at both 2-cell (r  = 0.71 ± 0.06) and 4-cell stages (r  = 0.77 ± 0.07). For degree of fragmentation, the pipeline (acc = 69.4%) slightly under-performs compared to human experts (acc = 73.8%). For developmental timing, the pipeline (acc = 90.0%) performs similarly to human experts (acc = 91.4%). There is also strong agreement between pipeline outputs and annotations made by embryologists during routine treatments. For fertilization status, the pipeline and embryologists strongly agree (acc = 79.6%), and there is strong correlation between the two measurements (r  = 0.683). For degree of fragmentation, the pipeline and embryologists mostly agree (acc = 55.4%), and there is also strong correlation between the two measurements (r  = 0.648). For both PN fade time (r  = 0.787) and time of blastulation (r  = 0.887), there's strong correlation between the pipeline and embryologists. For SET cycles, 2-cell time (P  < 0.01) and 2-cell symmetry (P  < 0.03) are significantly correlated with implantation success rate, while other features showed correlations with implantation success without statistical significance. In addition, 2-cell time (P  < 5 × 10−11), PN fade time (P  < 5 × 10−10), degree of fragmentation on Day 3 (P  < 5 × 10−4), and 2-cell symmetry (P  < 5 × 10−3) showed statistically significant correlation with the probability of the transferred embryo resulting in live birth. LIMITATIONS, REASONS FOR CAUTION We have not tested the BlastAssist pipeline on data from other clinics or other time-lapse microscopy (TLM) systems. The association study we conducted with live birth results do not take into account confounding variables, which will be necessary to construct an embryo selection algorithm. Randomized controlled trials (RCT) will be necessary to determine whether the pipeline can improve success rates in clinical IVF. WIDER IMPLICATIONS OF THE FINDINGS BlastAssist provides a comprehensive and holistic means of evaluating human embryos. Instead of using a black-box algorithm, BlastAssist outputs meaningful measurements of embryos that can be interpreted and corroborated by embryologists, which is crucial in clinical decision making. Furthermore, the unprecedentedly large dataset generated by BlastAssist measurements can be used as a powerful resource for further research in human embryology and IVF. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by Harvard Quantitative Biology Initiative, the NSF-Simons Center for Mathematical and Statistical Analysis of Biology at Harvard (award number 1764269), the National Institute of Heath (award number R01HD104969), the Perelson Fund, and the Sagol fund for embryos and stem cells as part of the Sagol Network. The authors declare no competing interests. TRIAL REGISTRATION NUMBER Not applicable. [ABSTRACT FROM AUTHOR]

STUDY QUESTION Are there cell lineage-related differences in the apoptotic rates and differentiation capacity of human blastocysts diagnosed as euploid, mosaic, and aneuploid after preimplantation genetic testing for aneuploidy (PGT-A) based on concurrent copy number and genotyping analysis? SUMMARY ANSWER Trophectoderm (TE) cells of mosaic and aneuploid blastocysts exhibit significantly higher levels of apoptosis and significantly reduced differentiation capacity compared to those of euploid blastocysts. WHAT IS KNOWN ALREADY Embryos diagnosed as mosaic after PGT-A can develop into healthy infants, yet understanding the reasons behind their reproductive potential requires further research. One hypothesis suggests that mosaicism can be normalized through selective apoptosis and reduced proliferation of aneuploid cells, but direct evidence of these mechanisms in human embryos is lacking. Additionally, data interpretation from studies involving mosaic embryos has been hampered by retrospective analysis methods and the high incidence of false-positive mosaic diagnoses stemming from the use of poorly specific PGT-A platforms. STUDY DESIGN, SIZE, DURATION Prospective cohort study performing colocalization of cell-lineage and apoptotic markers by immunofluorescence (IF). We included a total of 64 human blastocysts donated to research on Day 5 or 6 post-fertilization (dpf) by 43 couples who underwent in vitro fertilization treatment with PGT-A at IVI-RMA Valencia between September 2019 and October 2022. A total of 27 mosaic blastocysts were analyzed. PARTICIPANTS/MATERIALS, SETTING, METHODS The study consisted of two phases: Phase I (caspase-3, n = 53 blastocysts): n = 13 euploid, n = 22 mosaic, n = 18 aneuploid. Phase II (terminal deoxynucleotidyl transferase dUTP nick end labelling (TUNEL), n = 11 blastocysts): n = 2 euploid, n = 5 mosaic, n = 4 aneuploid. Following donation for research, vitrified blastocysts were warmed, cultured until re-expansion, fixed, processed for IF, and imaged using confocal microscopy. For each blastocyst, the following cell counts were conducted: total cells (DAPI+), TE cells (GATA3+), inner cell mass (ICM) cells (GATA3−/NANOG+), and apoptotic cells (caspase-3+ or TUNEL+). The incidence of apoptosis was calculated for each blastocyst by dividing the number of caspase-3+ cells (Phase I) or TUNEL+ cells (Phase II) by the number of TE or ICM cells. Statistical analysis was performed according to data type and distribution (P  < 0.05 was considered statistically significant). MAIN RESULTS AND THE ROLE OF CHANCE Phase I: Mosaic blastocysts displayed a similar number of total cells (49.6 ± 15 cells at 5 dpf; 58.8 ± 16.9 cells at 6 dpf), TE cells (38.8 ± 13.7 cells at 5 dpf; 49.2 ± 16.2 cells at 6 dpf), and ICM cells (10.9 ± 4.2 cells at 5 dpf; 9.7 ± 7.1 cells at 6 dpf) compared to euploid and aneuploid blastocysts (P  > 0.05). The proportion of TE cells retaining NANOG expression increased gradually from euploid blastocysts (9.7% = 63/651 cells at 5 dpf; 0% = 0/157 cells at 6 dpf) to mosaic blastocysts (13.1% = 104/794 cells at 5 dpf; 3.4% = 12/353 cells at 6 dpf) and aneuploid blastocysts (27.9% = 149/534 cells at 5 dpf; 4.6% = 19/417 cells at 6 dpf) (P  < 0.05). At the TE level, caspase-3+ cells were frequently observed (39% = 901/2310 cells). The proportion of caspase-3+ TE cells was significantly higher in mosaic blastocysts (44.1% ± 19.6 at 5 dpf; 43% ± 16.8 at 6 dpf) and aneuploid blastocysts (45.9% ± 16.1 at 5 dpf; 49% ± 15.1 at 6 dpf) compared to euploid blastocysts (26.6% ± 16.6 at 5 dpf; 17.5% ± 14.8 at 6 dpf) (P  < 0.05). In contrast, at the ICM level, caspase-3+ cells were rarely observed (1.9% = 11/596 cells), and only detected in mosaic blastocysts (2.6% = 6/232 cells) and aneuploid blastocysts (2.5% = 5/197 cells) (P  > 0.05). Phase II: Consistently, TUNEL+ cells were only observed in TE cells (32.4% = 124/383 cells). An increasing trend was identified toward a higher proportion of TUNEL+ cells in the TE of mosaic blastocysts (37.2% ± 21.9) and aneuploid blastocysts (39% ± 41.7), compared to euploid blastocysts (23% ± 32.5), although these differences did not reach statistical significance (P  > 0.05). LIMITATIONS, REASONS FOR CAUTION The observed effects on apoptosis and differentiation may not be exclusive to aneuploid cells. Additionally, variations in aneuploidies and unexplored factors related to blastocyst development and karyotype concordance may introduce potential biases and uncertainties in the results. WIDER IMPLICATIONS OF THE FINDINGS Our findings demonstrate a cell lineage-specific effect of aneuploidy on the apoptotic levels and differentiation capacity of human blastocysts. This contributes to unravelling the biological characteristics of mosaic blastocysts and supports the concept of clonal depletion of aneuploid cells in explaining their reproductive potential. STUDY FUNDING/COMPETING INTEREST(S) This work was funded by grants from Centro para el Desarrollo Tecnológico Industrial (CDTI) (20190022) and Generalitat Valenciana (APOTIP/2019/009). None of the authors has any conflict of interest to declare. TRIAL REGISTRATION NUMBER N/A. [ABSTRACT FROM AUTHOR]

During the oestrous cycle, the bovine endometrium undergoes morphological and functional changes, which are regulated by alterations in the levels of oestrogen and progesterone and consequent changes in gene expression. To clarify these changes before and after oestrus, RNA-seq was used to profile the transcriptome of oestrus-synchronized beef heifers. Endometrial samples were collected from 29 animals, which were slaughtered in six groups beginning 12 h after the withdrawal of intravaginal progesterone releasing devices until seven days post-oestrus onset (luteal phase). The groups represented proestrus, early oestrus, metoestrus and early dioestrus (luteal phase). Changes in gene expression were estimated relative to gene expression at oestrus. Ingenuity Pathway Analysis (IPA) was used to identify canonical pathways and functional processes of biological importance. A total of 5,845 differentially expressed genes (DEGs) were identified. The lowest number of DEGs was observed at the 12 h post-oestrus time point, whereas the greatest number was observed at Day 7 post-oestrus onset (luteal phase). A total of 2,748 DEGs at this time point did not overlap with any other time points. Prior to oestrus, Neurological disease and Organismal injury and abnormalities appeared among the top IPA diseases and functions categories, with upregulation of genes involved in neurogenesis. Lipid metabolism was upregulated before oestrus and downregulated at 48h post-oestrus, at which point an upregulation of immune-related pathways was observed. In contrast, in the luteal phase the Lipid metabolism and Small molecule biochemistry pathways were upregulated. [ABSTRACT FROM AUTHOR]

Background: Meiotic and mitotic errors often lead to aneuploidy and mosaicism. In this context, the self-correction mechanism enables the embryo to preferentially retain and preserve euploid cells through processes such as apoptosis, necrosis, or marginalization. This mechanism is thought to minimize the chance of genetic abnormalities during cell development. Materials and methods: A literature search for articles written in English from January 2013 to October 2023 was conducted on PubMed, EBSCO, and Scopus, using the keywords "self-correction," "self-repair," "aneuploidy," "mosaicism," and "embryo." Results: A total of 308 articles were collected, out of which 5 retrospective and 1 prospective study were selected based on inclusion criteria. Discussions: Investigations showed that embryos remove chromosomally abnormal cells, supporting the self-correction mechanism. aCGH has been used in 4 studies to demonstrate the presence of self-correction in mosaic embryos. Furthermore, a higher relative viability of polyploidies than complex aneuploidies was observed, suggesting early discrimination against complex aneuploidy, particularly those arising from mitotic origins. However, there are doubts about the reliability of preimplantation genetic testing for aneuploidy at the blastocyst stage, as it may lead to a high rate of false positives and the discarding of "good" embryos. Conclusions: Studies showed a self-correction mechanism in human embryos through the ability to expel abnormal cells. Further investigation is needed to elucidate the underlying mechanisms and determine optimal strategies for preimplantation genetic testing to fully understand and optimize the use of self-correction mechanisms in embryo assessment and selection. [ABSTRACT FROM AUTHOR]

Embryonal diapause is a characteristic feature of about 130 mammalian species. However, very few studies have addressed cryopreservation of diapausing embryos. This work is aimed to apply program freezing to blastocysts obtained from CD1 mice, which were at diapause state after ovariectomy and the subsequent hormonal therapy. Blastocysts collected from non-operated mice of the same strain served as controls. Some diapausing as well as non-diapausing frozen-thawed blastocysts demonstrated blastocoel re-expansion after 24 h of in vitro culture (IVC) indicating their viability after cryopreservation. Raman spectroscopy assessment of phenylalanine accumulation revealed that the fraction of new synthesized proteins was lower for non-frozen as well as for frozen-thawed diapausing blastocysts compared to non-diapausing ones. Although protein metabolism was reduced in diapausing embryos, most of the protein synthesis remained active. Cell number increased after 24 h of IVC in non-frozen as well as in the frozen-thawed blastocysts of the control but not of the diapause group. However, cell numbers were increased in frozen-thawed diapausing blastocysts after 47 h of IVC in a medium supplemented with putrescine. This indicates viability of frozen-thawed diapausing embryos after cryopreservation. Besides, protein metabolism was not affected by cryopreservation in diapausing and non-diapausing murine embryos indicating their viability. Our results demonstrated the possibility of successful cryopreservation of diapausing murine embryos. • Diapausing murine embryos survived cryopreservation. • Protein metabolism was reduced in diapausing murine embryos although remained active. • Protein metabolism was not affected by cryopreservation in diapausing murine embryos. [ABSTRACT FROM AUTHOR]

Background: Artificial Intelligence entails the application of computer algorithms to the huge and heterogeneous amount of morphodynamic data produced by Time-Lapse Technology. In this context, Machine Learning (ML) methods were developed in order to assist embryologists with automatized and objective predictive models able to standardize human embryo assessment. In this study, we aimed at developing a novel ML-based strategy to identify relevant patterns associated with the prediction of blastocyst development stage on day 5. Methods: We retrospectively analysed the morphokinetics of 575 embryos obtained from 80 women who underwent IVF at our Unit. Embryo morphokinetics was registered using the Geri plus® time-lapse system. Overall, 30 clinical, morphological and morphokinetic variables related to women and embryos were recorded and combined. Some embryos reached the expanded blastocyst stage on day 5 (BL Group, n = 210), some others did not (nBL Group, n = 365). Results: The novel EmbryoMLSelection framework was developed following four-steps: Feature Selection, Rules Extraction, Rules Selection and Rules Evaluation. Six rules composed by a combination of 8 variables were finally selected, and provided a predictive power described by an AUC of 0.84 and an accuracy of 81%. Conclusions: We provided herein a new feature-signature able to identify with an high performance embryos with the best developmental competence to reach the expanded blastocyst stage on day 5. Clear and clinically relevant cut-offs were identified for each considered variable, providing an objective tool for early embryo developmental assessment. [ABSTRACT FROM AUTHOR]

Our research focuses on expression patterns in human and mouse embryonic cardiomyocytes and endothelial cells at the single-cell level. We analyzed single-cell datasets containing different species, cardiac chambers, and cell types. We identified developmentally dynamic genes associated with different cellular lineages in the heart and explored their expression and possible roles during cardiac development. We used dynamic time warping, a method that aligns temporal sequences, to compare these developmental stages across two species. Our results indicated that atrial cardiomyocytes from E9.5 to E13.5 in mice corresponded to a human embryo age of approximately 5–6 weeks, whereas in ventricular cardiomyocytes, they corresponded to a human embryo age of 13–15 weeks. The endothelial cells in mouse hearts corresponded to 6–7-week-old human embryos. Next, we focused on expression changes in cardiac transcription factors over time in different species and chambers, and found that Prdm16 might be related to interspecies cardiomyocyte differences. Moreover, we compared the developmental trajectories of cardiomyocytes differentiated from human pluripotent stem cells and embryonic cells. This analysis explored the relationship between their respective developments and provided compelling evidence supporting the relevance of our dynamic time-warping results. These significant findings contribute to a deeper understanding of cardiac development across different species. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has precipitously changed the practice of transplanting fresh allografts. The safety measures adopted during the pandemic prompted the near-universal graft cryopreservation. However, the influence of cryopreserving allogeneic grafts on long-term transplant outcomes has emerged only in the most recent literature. In this review, the basic principles of cell cryopreservation are revised and the effects of cryopreservation on the different graft components are carefully reexamined. Finally, a literature revision on studies comparing transplant outcomes in patients receiving cryopreserved and fresh grafts is illustrated. [ABSTRACT FROM AUTHOR]

Mammalian preimplantation embryos often contain chromosomal defects that arose in the first divisions after fertilization and affect a subpopulation of cells -- an event known as mosaic aneuploidy. In this issue of the JCI, Chavli et al. report single-cell genomic sequencing data for rigorous evaluation of the incidence and degree of mosaic aneuploidy in healthy human in vitro fertilization (IVF) embryos. Remarkably, mosaic aneuploidy occurred in at least 80% of human blastocyst-stage embryos, with often less than 20% of cells showing defects. These findings confirm that mosaic aneuploidy is prevalent in human embryos, indicating that the process is a widespread event that rarely has clinical consequences. There are major implications for preimplantation genetic testing of aneuploidy (PGT-A), a test commonly used to screen and select IVF embryos for transfer. The application and benefit of this technology is controversial, and the findings provide more cause for caution on its use. [ABSTRACT FROM AUTHOR]

Importance: The first meta-analysis focused only on gonadotropin-releasing hormone (GnRH) antagonists, which helped determine the effect of delay trigger on pregnancy outcomes. Objective: To evaluate the impact of delay trigger compared with standard trigger in normal responders undergoing GnRH antagonist protocol in improving pregnancy outcomes. Methods: Studies published before April 2023 in PubMed, EMBASE, Cochrane Library, Web of Science, CNKI, Wanfang, VIP and CBM databases were searched. Randomized controlled trials (RCTs) and cohort studies conducted in normal responders reporting the efficacy of delay trigger using GnRH antagonist protocol were included. Data were combined to calculate mean differences (MD) for continuous variables and odd ratios (OR) for categorical variables with their corresponding 95% confidence intervals (CIs). Heterogeneity was assessed using Cochran's Q test. Results: Endpoints, including clinical pregnancy rate (CPR), live birth rate (LBR), the number of oocyte retrievals and embryos, and fertilization rate, were analyzed. Six (6) clinical studies (4 RCTs and 2 cohort studies) with 1,360 subjects were included. The pooled results showed that the number of oocyte retrievals (MD: 1.20, 95% CI: 1.10, 1.30, p < 0.01), fertilization rate (MD: 0.64, 95% CI: 0.29, 0.99, p < 0.01) and days of stimulation (MD: 0.95; 95% CI: 0.54, 1.37; p < 0.01) in the delay trigger group was significantly higher than that in the standard trigger group. However, there was no significant difference in the number of embryos (MD: 0.19, 95% CI: -0.29, 0.67, p = 0.44), CPR (OR: 1.12; 95% CI: 0.72, 1.75; p = 0.062), and LBR (OR: 1.23; 95% CI: 0.90, 1.66; p = 0.19) between the two trigger groups. Conclusion: Delaying trigger time in GnRH antagonist protocol increased the number of oocytes retrieved but not the number of embryos. Furthermore, delay trigger shot was not associated with a clinical benefit towards CPR and LBR in women who underwent fresh embryo transfer cycles. Trial registration: The International Prospective Register of Systematic Reviews (PROSPERO), registration number: CRD42023413217. [ABSTRACT FROM AUTHOR]