Mechanisms of minor pole-mediated spindle bipolarization in human oocytes.

Spindle bipolarization, the process of a microtubule mass transforming into a bipolar spindle, is a prerequisite for accurate chromosome segregation. In contrast to mitotic cells, the process and mechanism of spindle bipolarization in human oocytes remains unclear. Using high-resolution imaging in more than 1800 human oocytes, we revealed a typical state of multipolar intermediates that form during spindle bipolarization and elucidated the mechanism underlying this process. We found that the minor poles formed in multiple kinetochore clusters contribute to the generation of multipolar intermediates. We further determined the essential roles of HAUS6, KIF11, and KIF18A in spindle bipolarization and identified mutations in these genes in infertile patients characterized by oocyte or embryo defects. These results provide insights into the physiological and pathological mechanisms of spindle bipolarization in human oocytes.

Luteal phase support with oral progesterone improves live birth rate in intrauterine insemination cycles using letrozole.

RESEARCH QUESTION: Does luteal phase support (LPS) with oral progesterone improve the live birth rate (LBR) in patients undergoing intrauterine insemination (IUI) cycles with letrozole? DESIGN: This retrospective cohort study included 1199 IUI cycles with letrozole between January 2017 and December 2021. A nearest neighbour random matching approach was employed to pair the LPS group and the control group in a 1:2 ratio. Eight variables were chosen for matching in the propensity score matching (PSM) model: age; body mass index; duration of infertility; cause(s) of infertility; antral follicle count; basal concentration of FSH; rank of IUI attempts; and leading follicle size. LBR was selected as the primary outcome. RESULTS: In total, 427 LPS cycles were matched with 772 non-LPS (control) cycles after PSM. The LBR was significantly higher in the LPS group compared with the control group (19.7% versus 14.5%; P = 0.0255). The clinical pregnancy rate (23.2% versus 17.6%; P = 0.0245) and ongoing pregnancy rate (20.6% versus 15.8%; P = 0.0437) were also significantly higher in the LPS group. The biochemical pregnancy rate, ectopic pregnancy rate and miscarriage rate were similar in the two groups (P > 0.05). The intergroup comparison revealed no significant variances in terms of gestational age, mode of delivery, ectopic pregnancy rate or abortion rate. Furthermore, there were no significant differences in birth weight or birth length between the two groups. CONCLUSIONS: Luteal support with oral progesterone significantly improved the LBR in IUI cycles with letrozole, but did not affect neonatal outcomes.

Secondary follicles enable efficient germline mtDNA base editing at hard-to-edit site.

Efficient germline mtDNA editing is required to construct disease-related animal models and future gene therapy. Recently, the DddA-derived cytosine base editors (DdCBEs) have made mitochondrial genome (mtDNA) precise editing possible. However, there still exist challenges for editing some mtDNA sites in germline via zygote injection, probably due to the suspended mtDNA replication during preimplantation development. Here, we introduce a germline mtDNA base editing strategy: injecting DdCBEs into oocytes of secondary follicles, at which stage mtDNA replicates actively. With this method, we successfully observed efficient G-to-A conversion at a hard-to-edit site and also obtained live animal models. In addition, for those editable sites, this strategy can greatly improve the base editing efficiency up to 3-fold, which is more than that in zygotes. More important, editing in secondary follicles did not increase more the risk of off-target effects than that in zygotes. This strategy provides an option to efficiently manipulate mtDNA sites in germline, especially for hard-to-edit sites.

Disruption in CYLC1 leads to acrosome detachment, sperm head deformity, and male in/subfertility in humans and mice.

The perinuclear theca (PT) is a dense cytoplasmic web encapsulating the sperm nucleus. The physiological roles of PT in sperm biology and the clinical relevance of variants of PT proteins to male infertility are still largely unknown. We reveal that cylicin-1, a major constituent of the PT, is vital for male fertility in both mice and humans. Loss of cylicin-1 in mice leads to a high incidence of malformed sperm heads with acrosome detachment from the nucleus. Cylicin-1 interacts with itself, several other PT proteins, the inner acrosomal membrane (IAM) protein SPACA1, and the nuclear envelope (NE) protein FAM209 to form an 'IAM-cylicins-NE' sandwich structure, anchoring the acrosome to the nucleus. WES (whole exome sequencing) of more than 500 Chinese infertile men with sperm head deformities was performed and a CYLC1 variant was identified in 19 patients. Cylc1-mutant mice carrying this variant also exhibited sperm acrosome/head deformities and reduced fertility, indicating that this CYLC1 variant most likely affects human male reproduction. Furthermore, the outcomes of assisted reproduction were reported for patients harbouring the CYLC1 variant. Our findings demonstrate a critical role of cylicin-1 in the sperm acrosome-nucleus connection and suggest CYLC1 variants as potential risk factors for human male fertility.

Harnessing accurate mitochondrial DNA base editing mediated by DdCBEs in a predictable manner.

Introduction: Mitochondrial diseases caused by mtDNA have no effective cures. Recently developed DddA-derived cytosine base editors (DdCBEs) have potential therapeutic implications in rescuing the mtDNA mutations. However, the performance of DdCBEs relies on designing different targets or improving combinations of split-DddA halves and orientations, lacking knowledge of predicting the results before its application. Methods: A series of DdCBE pairs for wide ranges of aC or tC targets was constructed, and transfected into Neuro-2a cells. The mutation rate of targets was compared to figure out the potential editing rules. Results: It is found that DdCBEs mediated mtDNA editing is predictable: 1) aC targets have a concentrated editing window for mtDNA editing in comparison with tC targets, which at 5'C8-11 (G1333) and 5'C10-13 (G1397) for aC target, while 5'C4-13 (G1333) and 5'C5-14 (G1397) for tC target with 16bp spacer. 2) G1333 mediated C>T conversion at aC targets in DddA-half-specific manner, while G1333 and G1397 mediated C>T conversion are DddA-half-prefer separately for tC and aC targets. 3) The nucleotide adjacent to the 3' end of aC motif affects mtDNA editing. Finally, by the guidance of these rules, a cell model harboring a pathogenic mtDNA mutation was constructed with high efficiency and no bystander effects. Discussion: In summary, this discovery helps us conceive the optimal strategy for accurate mtDNA editing, avoiding time- and effort-consuming optimized screening jobs.

Identification novel mutations and phenotypic spectrum expanding in PATL2 in infertile women with IVF/ICSI failure.

AIM: Abnormalities in oocyte maturation, fertilization, and early embryonic development are major causes of primary infertility in women who are undergoing IVF/ICSI attempts. Although many genetic factors responsible for these abnormal phenotypes have been identified, there are more additional pathogenic genes and variants yet to be discovered. Previous studies confirmed that bi-allelic PATL2 deficiency is an important factor for female infertility. In this study, 935 infertile patients with IVF/ICSI failure were selected for whole-exome sequencing, and 18 probands carrying PATL2 variants with a recessive inheritance pattern were identified. METHODS: We estimated that the prevalence contributed by PATL2 was 1.93% (18/935) in our study cohort. RESULTS: 15 novel variants were found in those families, including c.1093C > T, c.1609dupA, c.1204C > T, c.643dupG, c.877-2A > G, c.1228C > G, c.925G > A, c.958G > A, c.4A > G, c.1258T > C, c.1337G > A, c.1264dupA, c.88G > T, c.1065-2A > G, and c.1271T > C. The amino acids altered by the corresponding variants were highly conserved in mammals, and in silico analysis and 3D molecular modeling suggested that the PATL2 mutants impaired the physiologic function of the resulting proteins. Diverse clinical phenotypes, including oocyte maturation defect, fertilization failure, and early embryonic arrest might result from different variants of PATL2. CONCLUSIONS: These results expand the spectrum of PATL2 variants and provide an important reference for genetic counseling for female infertility, and they increase our understanding of the mechanisms of oocyte maturation arrest caused by PATL2 deficiency.

The press-assisted fusion scheme significantly mitigates the quantity of HVJ-E required in mitochondrial replacement techniques.

In brief: The impact of HVJ-E employed in mitochondrial replacement techniques (MRTs) on embryonic development remains uncertain. This study has exhibited the influence of HVJ-E utilized in MRTs on embryonic development and has devised a novel HVJ-E-induced fusion approach to curtail the amount of HVJ-E employed in MRTs. Abstract: Mitochondrial replacement techniques (MRTs) provide a viable option for women carrying pathogenic mitochondrial DNA (mtDNA) variants to conceive disease-free offspring with a genetic connection. In comparison to electrofusion, HVJ-E-induced fusion has been identified as the most promising approach for clinical translation of MRTs due to its absence of electrical interference. However, despite confirmation of the absence of RNA activity in HVJ-E, a reduction in blastocyst quality has been observed in various MRTs studies utilizing the HVJ-E-induced fusion scheme. Recent investigations have revealed a dose-dependent elevation of reactive oxygen species (ROS) levels in various cancer cells incubated with HVJ-E. However, the impact of HVJ-E as a sole determinant on embryonic development in MRTs remains unverified. This investigation establishes that the augmented concentration of HVJ-E utilized in the conventional HVJ-E fusion protocol is an autonomous variable that influences embryonic development in MRTs. This effect may be attributed to amplified DNA damage resulting from heightened levels of ROS in reconstructed embryos. To mitigate the presence of HVJ-E in reconstructed zygotes while maintaining optimal fusion efficiency in MRTs, a novel HVJ-E-induced fusion approach was devised, namely, press-assisted fusion. This technique offers potential advantages in reducing detrimental factors that impede embryo development in MRTs.

Bi-allelic missense variants in MEI4 cause preimplantation embryonic arrest and female infertility.

Preimplantation embryonic arrest is an important pathogenesis of female infertility, but little is known about the genetic factors behind this phenotype. MEI4 is an essential protein for DNA double-strand break formation during meiosis, and Mei4 knock-out female mice are viable but sterile, indicating that MEI4 plays a crucial role in reproduction. To date, MEI4 has not been found to be associated with any human reproductive diseases. Here, we identified six compound heterozygous and homozygous MEI4 variants-namely, c.293C > T, p.(Ser98Leu), c.401C > G, p.(Pro134Arg), c.391C > G, p.(Pro131Ala), c.914A > T, p.(Tyr305Phe), c.908C > G, p.(Ala303Gly), and c.899A > T, p.(Gln300Leu)-in four independent families that were responsible for female infertility mainly characterized by preimplantation embryonic arrest. In vitro, we found that these variants reduced the interaction between MEI4 and DNA. In vivo, we generated a knock-in mouse model and demonstrated that female mice were infertile and were characterized by developmental defects during oogenesis. Our findings reveal the important roles of MEI4 in human reproduction and provide a new diagnostic marker for genetic counseling of clinical infertility patients.

Effect of small follicles on clinical pregnancy and multiple pregnancy rates in intrauterine insemination: a cohort study.

STUDY QUESTION: What is the effect of small follicles on clinical pregnancy and multiple pregnancy rates in women undergoing IUI with ovarian stimulation (IUI-OS)? SUMMARY ANSWER: The presence of ≥2 small follicles with a diameter of 10-12 or 12-14 mm was associated with an increased chance of clinical pregnancy and the presence of any 12-14 mm or larger follicles, but not smaller follicles, was statistically significantly associated with an increased risk for multiple pregnancy. WHAT IS KNOWN ALREADY: IUI-OS is widely used as the first-line treatment for unexplained or mild male factor infertility. However, IUI is associated with the risk of multiple pregnancy. While the positive association between the number of follicles ≥14 mm and the chance of pregnancy and the risk of multiple pregnancy is known, the impact of smaller follicles is uncertain. STUDY DESIGN, SIZE, DURATION: This was a retrospective cohort study that included women undergoing IUI cycles from January 2007 to May 2021 in one assisted reproduction center. PARTICIPANTS/MATERIALS, SETTING, METHODS: We studied the impact of the number and size of follicles on trigger day on clinical pregnancy and multiple pregnancy rates. Generalized estimation equation regression models were used to compute unadjusted and adjusted odds ratios and 95% CI in all women and only women who achieved clinical pregnancy separately. The chance of clinical pregnancy and multiple pregnancy for different numbers of small follicles in cycles with one >18-mm follicle was calculated using marginal effects estimate. MAIN RESULTS AND THE ROLE OF CHANCE: This cohort included 12 933 IUI cycles in 7504 women. The overall clinical pregnancy rate was 16.1% (2081/12 933), with a multiple pregnancy rate of 10.5% (218/2081). In the adjusted analysis, the chance of clinical pregnancy increased significantly with the increase in the number of follicles with the diameter of 14-16, 16-18, and 18-20 mm. As for 10-12 mm [adjusted odds ratio (aOR) 1.22, 95% CI 1.02-1.46] and 12-14 mm (aOR 1.29, 95% CI 1.07-1.56) follicles, only groups with ≥2 follicles of those sizes showed significantly increased chance of clinical pregnancy. In cycles that led to pregnancy, follicles with the diameter of 12-14 mm were associated with an increased risk of multiple pregnancy (aOR 1.73, 95% CI 1.19-2.53 for one such follicle; aOR 2.27, 95% CI 1.44-3.56 for ≥2 such follicles), while 10- to 12-mm follicles were not significantly associated with multiple pregnancy (aOR 1.18, 95% CI 0.72-1.95 for ≥2 such follicles). The associations of multiple pregnancy were similar when including all cycles. LIMITATIONS, REASONS FOR CAUTION: This was a retrospective observational study from a single center. The records of follicle diameter in our center were of a 2-mm interval which limited our ability to analyze the size of follicle as a continuous variable. Also, the number of cycles with a high number of small follicles was still limited which impeded more detailed analysis on the ≥2 follicles subgroup. Similarly, the value of some parts of the marginal probability estimation for multiple pregnancy versus pregnancy according to size and number of follicles was also limited by the low sample size of certain combinations. WIDER IMPLICATIONS OF THE FINDINGS: Follicles larger than 10 mm, especially those ≥12 mm, may need to be clearly recorded during transvaginal ultrasound surveillance and their potential effects on both pregnancy and multiple pregnancy can be discussed with couples undergoing IUI. STUDY FUNDING/COMPETING INTEREST(S): This work was supported by the National Natural Science Foundation of China (Grant numbers 82201912, 82371651, and 82071615) and Shanghai Sailing Program (21YF1423200). B.W.M. is supported by an NHMRC Investigator grant (GNT1176437). B.W.M. reports consultancy for ObsEva and Merck and travel support from Merck. B.W.M. has received research funding from Ferring and Merck. The authors declare no other competing interests. TRIAL REGISTRATION NUMBER: N/A.

Conhecimento, atitude e prática de emergência pré-hospitalar e seus fatores de influência entre cuidadores de idosos: pesquisa transversal / Conocimientos, actitudes y prácticas de emergencias prehospitalarias y sus factores de influencia en cuidadores de personas mayores: estudio transversal / Knowledge, attitude, and practice of pre-hospital emergency and their influencing factors among caregivers for older adults: a cross-sectional survey

Resumo Objetivo Investigar a situação atual e analisar os fatores influenciadores do conhecimento, atitude e prática de emergência pré-hospitalar entre cuidadores de idosos. Métodos Estudo transversal com amostragem por conveniência, conduzido entre dezembro de 2021 e junho de 2022, e seleção de 133 cuidadores de idosos em instituições de longa permanência na província de Guangdong, China, como participantes. Todos receberam um questionário de informações gerais e um questionário de conhecimento, atitude e prática de emergência pré-hospitalar. Na análise dos dados foi utilizada estatística descritiva e inferencial. Resultados As pontuações nas dimensões conhecimento, atitude e prática foram 24,65 ± 4,49, 24,52 ± 4,34 e 24,05 ± 4,67, respectivamente. A análise de regressão mostrou que a idade, o nível de habilidade profissional e a experiência em educação em saúde dos cuidadores foram os principais fatores que influenciaram seu conhecimento de emergência pré-hospitalar. A presença/ausência dos cuidadores na participação direta na emergência pré-hospitalar foi o principal fator de influência na atitude, enquanto o nível educacional e a situação profissional foram os fatores que influenciaram principalmente a prática na emergência pré-hospitalar. Conclusão O atual nível de conhecimento, atitude e prática em emergência pré-hospitalar dos cuidadores de idosos é de baixo a médio. Para os cuidadores chineses, os principais fatores que afetam a implementação da emergência pré-hospitalar são a idade avançada, os baixos níveis de escolaridade, o emprego temporário e as deficiências do sistema de segurança ocupacional.

Resumen Objetivo Investigar la situación actual y analizar factores influyentes de los conocimientos, actitudes y prácticas de emergencias prehospitalarias en cuidadores de personas mayores. Métodos Estudio transversal con muestreo por conveniencia, llevado a cabo entre diciembre de 2021 y junio de 2022. Se seleccionaron 133 participantes cuidadores de personas mayores de instituciones de larga estadía en la provincia de Guangdong, China. Todos recibieron un cuestionario de información general y un cuestionario de conocimientos, actitudes y prácticas de emergencias prehospitalarias. En el análisis de los datos se utilizó estadística descriptiva e inferencial. Resultados El puntaje en la dimensión conocimientos fue 24,65 ± 4,49, en actitudes fue 24,52 ± 4,34 y en prácticas 24,05 ± 4,67. El análisis de regresión demostró que los principales factores que influyeron en los conocimientos de los cuidadores sobre emergencias prehospitalarias fueron la edad, el nivel de habilidad profesional y la experiencia en educación para la salud. La presencia/ausencia de los cuidadores en la participación directa en emergencias prehospitalarias fue el factor principal de influencia en la actitud, mientras que el nivel educativo y la situación profesional fueron los que más influyeron en la práctica de emergencias prehospitalarias. Conclusión El nivel actual de conocimientos, actitudes y prácticas en emergencias prehospitalarias de los cuidadores de personas mayores es de bajo a mediano. En los cuidadores chinos, los principales factores que afectan la implementación de emergencias prehospitalarias son la edad avanzada, los bajos niveles de escolaridad, el empleo temporario y las deficiencias del sistema de seguridad laboral.

Abstract Objective To investigate the status quo and analyze the influencing factors of the knowledge, attitude, and practice of pre-hospital emergency among caregivers for older adults. Methods In this cross-sectional study, 133 caregivers for older adults in Guangdong province, China, nursing homes were selected as survey participants from December 2021 to June 2022 via convenience sampling. All participants were administered a general information questionnaire and a Pre-Hospital Emergency Knowledge, Attitude, and Practice Questionnaire. For data analysis, we used descriptive and inferential statistics. Results The scores on the knowledge, attitude, and practice dimensions were 24.65 ± 4.49, 24.52 ± 4.34, and 24.05 ± 4.67, respectively. Regression analysis showed that the age, professional skill level, and healthcare education experience of the caregivers were the main influencing factors of their pre-hospital emergency knowledge. Additionally, the presence/absence of direct participation in the pre-hospital emergency of the caregivers was the primary influencing factor of attitude, while education level and employment status were the factors mainly influencing pre-hospital emergency practice. Conclusion Caregivers for older adults currently have a low-to-medium level of knowledge, attitude, and practice of pre-hospital emergency. The main factors affecting the implementation of pre-hospital emergency for caregivers in China are their older age, low education levels, temporary employment and imperfect occupational security system.

Significant decrease of maternal mitochondria carryover using optimized spindle-chromosomal complex transfer.

Mutations in mitochondrial DNA (mtDNA) contribute to a variety of serious multi-organ human diseases, which are strictly inherited from the maternal germline. However, there is currently no curative treatment. Attention has been focused on preventing the transmission of mitochondrial diseases through mitochondrial replacement (MR) therapy, but levels of mutant mtDNA can often unexpectedly undergo significant changes known as mitochondrial genetic drift. Here, we proposed a novel strategy to perform spindle-chromosomal complex transfer (SCCT) with maximal residue removal (MRR) in metaphase II (MII) oocytes, thus hopefully eliminated the transmission of mtDNA diseases. With the MRR procedure, we initially investigated the proportions of mtDNA copy numbers in isolated karyoplasts to those of individual oocytes. Spindle-chromosomal morphology and copy number variation (CNV) analysis also confirmed the safety of this method. Then, we reconstructed oocytes by MRR-SCCT, which well developed to blastocysts with minimal mtDNA residue and normal chromosomal copy numbers. Meanwhile, we optimized the manipulation order between intracytoplasmic sperm injection (ICSI) and SCC transfer and concluded that ICSI-then-transfer was conducive to avoid premature activation of reconstructed oocytes in favor of normal fertilization. Offspring of mice generated by embryos transplantation in vivo and embryonic stem cells derivation further presented evidences for competitive development competence and stable mtDNA carryover without genetic drift. Importantly, we also successfully accomplished SCCT in human MII oocytes resulting in tiny mtDNA residue and excellent embryo development through MRR manipulation. Taken together, our preclinical mouse and human models of the MRR-SCCT strategy not only demonstrated efficient residue removal but also high compatibility with normal embryo development, thus could potentially be served as a feasible clinical treatment to prevent the transmission of inherited mtDNA diseases.

The effect of gonadotrophin-releasing hormone agonist versus human chorionic gonadotrophin trigger on pregnancy and neonatal outcomes in Letrozole-HMG IUI cycles.

BACKGROUND: GnRHa and hCG are both used for oocyte maturation and ovulation triggering. However, GnRHa have a shorter half-life than hCG, which leads to luteal phase deficiency. Letrozole (LE) has been found to improve the luteal function. Thus, the choice of triggering strategy can be different in intrauterine insemination (IUI) cycles using LE and human menopausal gonadotropin (HMG). The aim of this study was to compare the pregnancy and neonatal outcomes of patients triggered with GnRHa versus hCG versus dual trigger in LE-IUI cycles. METHODS: This retrospective cohort study included 6,075 LE-HMG IUI cycles between January 2010 and May 2021 at a tertiary-care academic medical center in China. All cycles were divided into three groups according to different trigger strategies as hCG trigger group, GnRHa trigger group and dual trigger group. The primary outcome was clinical pregnancy rate. Logistic regression analysis was performed to explore other risk factors for clinical pregnancy rate. RESULTS: No significant difference was observed in clinical pregnancy rate between hCG, GnRHa and dual trigger cycles in LE-HMG IUI cycles (P = 0.964). The miscarriage rate was significantly lower in the GnRHa trigger group, and higher in the dual trigger group, compared with the hCG group (P = 0.045). Logistic analysis confirmed that triggering strategy was associated with miscarriage (aOR:0.427, 95%CI: 0.183-0.996, P = 0.049; aOR:0.298, 95%CI: 0.128-0.693, P = 0.005). No significant differences were observed regarding neonatal outcomes between the three groups. CONCLUSIONS: Our findings suggested that both GnRHa and dual trigger can be used to trigger ovulation in LE-HMG IUI cycles, but dual trigger must be used with caution.

A delayed ovulation of progestin-primed ovarian stimulation (PPOS) by downregulating the LHCGR/PGR pathway.

Progestin-primed ovarian stimulation (PPOS) is a new ovulation stimulation protocol, and its role in ovulation and regulatory mechanism is unclear. The clinical PPOS protocol was simulated in mice. The ovulated oocytes, estradiol, progesterone, and luteinizing hormone (LH) levels were analyzed at different hours after trigger. mRNA extraction and real-time PCR, hematoxylin and eosin staining, and immunofluorescence of ovaries were used to explore the involved signaling pathways. The PPOS group had a delayed ovulation at 12.5 h after trigger. Its suppressed LH level reduced the expression of luteinizing hormone/choriogonadotropin receptor (LHCGR) on the preovulatory follicles before trigger and significantly decreased the following progesterone synthesis, blood progesterone level, and progesterone receptor (PGR) expression within 4-6 h after trigger. Furthermore, the important ovulatory genes regulated by PGR including ADAMTS-1, VEGF-A, and EDN2 were downregulated, ultimately delaying the ovulation. PPOS suppresses the LH level before trigger and decreases the synthesis of progesterone after trigger, thus delaying the ovulation by downregulating the LHCGR-PGR pathway.

Does Day 3 embryo status matter to reproductive outcomes of single blastocyst transfer cycles? A cohort study.

OBJECTIVE: To investigate whether Day 3 (D3) embryo status matter to reproductive outcomes of blastocyst transfer cycles. DESIGN: Retrospective cohort study. SETTING: Assisted Reproduction Department of Shanghai Ninth People's Hospital, Shanghai, China. POPULATION: A total of 6906 vitrified-thawed single blastocyst transfer cycles in 6502 women were included. METHODS: Generalised estimated equation regression models were used to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the associations between embryo status and pregnancy outcomes. MAIN OUTCOME MEASURES: Biochemical pregnancy, miscarriage, live birth. RESULTS: High-quality blastocysts derived from poor-grade D3 embryos had comparable pregnancy outcomes to those derived from high-grade D3 embryos (40.0% versus 43.2%, aOR 1.00, 95% CI 0.85-1.17 for live birth rate; 8.3% versus 9.5%, aOR 0.82, 95% CI 0.63-1.07 for miscarriage rate). Cycles with low D3 cell number (five cells or fewer) had significantly higher miscarriage rate (9.2% versus 7.6%, aOR 1.33, 95% CI 1.02-1.75) compared with cycles with eight cells on D3. CONCLUSIONS: Poor-quality cleavage embryos should be cultivated to the blastocyst stage because high-quality blastocysts derived from poor-grade D3 embryos had acceptable pregnancy outcomes. When the blastocyst grade is identical, choosing embryos with higher D3 cell number (eight or more cells) for transfer could reduce the risk of early miscarriage.

Bi-allelic variants in ASTL cause abnormal fertilization or oocyte maturation defects.

Fertilization is a fundamental process of development, and the blocking mechanisms act at the zona pellucida (ZP) and plasma membrane of the egg to prevent any additional sperm from binding, permeating and fusing after fertilization. In clinical practice, some couples undergoing recurrent IVF failures that mature oocytes had abnormal fertilization for unknown reason. Ovastacin encoded by ASTL cleave the ZP protein ZP2 and play a key role in preventing polyspermy. Here, we identified bi-allelic variants in ASTL that are mainly characterized by fertilization problems in humans. All four independent affected individuals had bi-allelic frameshift variants or predicted damaging missense variants, which follow a Mendelian recessive inheritance pattern. The frameshift variants significantly decreased the quantity of ASTL protein in vitro. And all missense variants affected the enzymatic activity that cleaves ZP2 in mouse egg in vitro. Three knock-in female mice (corresponding to three missense variants in patients) all show subfertility due to low embryo developmental potential. This work presents strong evidence that pathogenic variants in ASTL cause female infertility and provides a new genetic marker for the diagnosis of fertilization problems.

Earlier second polar body transfer and further mitochondrial carryover removal for potential mitochondrial replacement therapy.

The second polar body (PB2) transfer in assisted reproductive technology is regarded as the most promising mitochondrial replacement scheme for preventing the mitochondrial disease inheritance owing to its less mitochondrial carryover and stronger operability. However, the mitochondrial carryover was still detectable in the reconstructed oocyte in conventional second polar body transfer scheme. Moreover, the delayed operating time would increase the second polar body DNA damage. In this study, we established a spindle-protrusion-retained second polar body separation technique, which allowed us to perform earlier second polar body transfer to avoid DNA damage accumulation. We could also locate the fusion site after the transfer through the spindle protrusion. Then, we further eliminated the mitochondrial carryover in the reconstructed oocytes through a physically based residue removal method. The results showed that our scheme could produce a nearly normal proportion of normal-karyotype blastocysts with further reduced mitochondrial carryover, both in mice and humans. Additionally, we also obtained mouse embryonic stem cells and healthy live-born mice with almost undetectable mitochondrial carryover. These findings indicate that our improvement in the second polar body transfer is conducive to the development and further mitochondria carryover elimination of reconstructed embryos, which provides a valuable choice for future clinical applications of mitochondrial replacement.

Role of luteinizing hormone elevation in outcomes of ovulation induction with letrozole for polycystic ovary syndrome.

Introduction: The effect of elevated luteinizing hormone (LH) on the clinical outcomes of ovulation induction (OI) in infertile anovulatory patients with polycystic ovary syndrome (PCOS) remains controversial. This retrospective study included PCOS patients undergoing intrauterine insemination (IUI) following letrozole (LE) stimulation without OC pretreatment. Materials and methods: A retrospective cohort analysis was conducted in a single, academic ART center from January 2013 to May 2019. In total, 835 IUI cycles of PCOS patients treated with letrozole were collected for the analysis. Cohorts were separated based on the level of basal LH (bLH) and LH level after letrozole administration (LHle) during OI. OI response and reproductive outcomes were evaluated for each cohort. Results: No adverse effects of dysregulated levels of either bLH or LHle on ovulation rate or reproductive outcomes were observed. Furthermore, the cohort of individuals with normal bLH and high LHle levels, exclusive of LH surge, exhibited significantly higher rates of clinical pregnancy (30.3% vs. 17.3%, p = 0.002) and live birth (24.2% vs. 15.2%, p = 0.024) than those with normal bLH and normal LHle. Conclusion: These results indicated that high LH levels in PCOS are not solid evidence of poor prognosis of letrozole-induced ovulation, while elevated LHle may be a prospective predictor for better OI outcomes. It seems that preinhibition of LH secretion is not needed.

Large-scale analysis of de novo mutations identifies risk genes for female infertility characterized by oocyte and early embryo defects.

BACKGROUND: Oocyte maturation arrest and early embryonic arrest are important reproductive phenotypes resulting in female infertility and cause the recurrent failure of assisted reproductive technology (ART). However, the genetic etiologies of these female infertility-related phenotypes are poorly understood. Previous studies have mainly focused on inherited mutations based on large pedigrees or consanguineous patients. However, the role of de novo mutations (DNMs) in these phenotypes remains to be elucidated. RESULTS: To decipher the role of DNMs in ART failure and female infertility with oocyte and embryo defects, we explore the landscape of DNMs in 473 infertile parent-child trios and identify a set of 481 confident DNMs distributed in 474 genes. Gene ontology analysis reveals that the identified genes with DNMs are enriched in signaling pathways associated with female reproductive processes such as meiosis, embryonic development, and reproductive structure development. We perform functional assays on the effects of DNMs in a representative gene Tubulin Alpha 4a (TUBA4A), which shows the most significant enrichment of DNMs in the infertile parent-child trios. DNMs in TUBA4A disrupt the normal assembly of the microtubule network in HeLa cells, and microinjection of DNM TUBA4A cRNAs causes abnormalities in mouse oocyte maturation or embryo development, suggesting the pathogenic role of these DNMs in TUBA4A. CONCLUSIONS: Our findings suggest novel genetic insights that DNMs contribute to female infertility with oocyte and embryo defects. This study also provides potential genetic markers and facilitates the genetic diagnosis of recurrent ART failure and female infertility.

Letrozole cotreatment improves the follicular output rate in high-body-mass-index women with polycystic ovary syndrome undergoing IVF treatment.

Background: Women who have polycystic ovary syndrome (PCOS) with high body mass index (BMI) typically have an attenuated ovarian response and decreased follicular size, which are linked to unfavourable clinical outcomes following in vitro fertilization (IVF) therapy. The follicular output rate (FORT), a qualitative indicator of follicular response, seems to be positively linked to the clinical outcomes of IVF. Progestin-primed ovarian stimulation (PPOS) has become an alternative to gonadotropin-releasing hormone (GnRH) analogues to inhibit the premature luteinizing hormone (LH) surge. As letrozole (LE) shows promise in enhancing ovarian response, we compared PPOS with and without LE for PCOS in high BMI women with a focus on the FORT and associated clinical and pregnancy outcomes. Methods: For the recruited 1508 women, ten variables including AFC; age; basal sex hormone level; BMI; infertility type; period of infertility and number of previous IVF attempts were chosen in the propensity score matching (PSM) model to match 1374 women who taken the MPA+ hMG protocol with 134 women who received the MPA+ hMG+ LE treatment at a 1:1 ratio. FORT was selected as the primary outcome measure. The number of oocytes retrieved, viable embryos, hMG dosage, duration, oocyte maturity rate, fertilization rate, and implantation rate were established as secondary outcomes. Results: FORT was substantially elevated in the MPA+hMG+LE group compared with the MPA+hMG group (61% [35%, 86%] vs. 40% [25%, 60%], P <.001). Interestingly, the LE cotreatment group had a considerably lower mature oocyte rate despite having a similar number of mature oocytes and embryos recovered. The average hMG dosages and durations in the study group were similar to those in the control group. The implantation rate in the study group was numerically higher but without statistic significant than that in the control groups (43.15% (107/248) vs. 38.59% (115/298), OR 1.008, 95% CI 0.901-1.127; P >.05). Conclusion: The effect of LE combined with PPOS on FORT is better than the effect of the standard PPOS treatment in women with PCOS and a high BMI, but there is no substantially beneficial impact on pregnancy outcomes or the cycle features of COS, including consumption of hMG.

ADGB variants cause asthenozoospermia and male infertility.

Asthenozoospermia is one of the main factors leading to male infertility, but the genetic mechanisms have not been fully elucidated. Variants in the androglobin (ADGB) gene were identified in an infertile male characterized by asthenozoospermia. The variants disrupted the binding of ADGB to calmodulin. Adgb-/- male mice were infertile due to reduced sperm concentration (< 1 × 106 /mL) and motility. Spermatogenesis was also abnormal, with malformation of both elongating and elongated spermatids, and there was an approximately twofold increase in apoptotic cells in the cauda epididymis. These exacerbated the decline in sperm motility. It is surprising that ICSI with testicular spermatids allows fertilization and eventually develops into blastocyst. Through mass spectrometry, we identified 42 candidate proteins that are involved in sperm assembly, flagella formation, and sperm motility interacting with ADGB. In particular, CFAP69 and SPEF2 were confirmed to bind to ADGB. Collectively, our study suggests the potential important role of ADGB in human fertility, revealing its relevance to spermatogenesis and infertility. This expands our knowledge of the genetic causes of asthenozoospermia and provides a theoretical basis for using ADGB as an underlying genetic marker for infertile males.