Human 8-cell embryos enable efficient induction of disease-preventive mutations without off-target effect by cytosine base editor

Approximately 140 million people worldwide are homozygous carriers of APOE4 (ε4), a strong genetic risk factor for late onset familial and sporadic Alzheimer's disease (AD), 91% of whom will develop AD at earlier age than heterozygous carriers and noncarriers. Susceptibility to AD could be reduced by targeted editing of APOE4, but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies. Here, we first screened eight cytosine base editor variants at four injection stages (from 1- to 8-cell stage), and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate (up to 100%) with the lowest bystander effects. In particular, 80% of AD-susceptible ε4 allele copies were converted to the AD-neutral ε3 allele in human ε4-carrying embryos. Stringent control measures combined with targeted deep sequencing, whole genome sequencing, and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells. Furthermore, base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage. Finally, we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia. Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos, a potential approach for reducing human susceptibility to AD or other genetic diseases.

Modeling human pregastrulation development by 3D culture of blastoids generated from primed-to-naïve transitioning intermediates

Human pluripotent stem cells provide an inexhaustible model to study human embryogenesis in vitro. Recent studies have provided diverse models to generate human blastoids by self-organization of different pluripotent stem cells or somatic reprogramming intermediates. However, whether blastoids can be generated from other cell types or whether they can recapitulate postimplantation development in vitro is unknown. Here, we develop a strategy to generate human blastoids from heterogeneous intermediates with epiblast, trophectoderm, and primitive endoderm signatures of the primed-to-naïve conversion process, which resemble natural blastocysts in morphological architecture, composition of cell lineages, transcriptome, and lineage differentiation potential. In addition, these blastoids reflect many features of human peri-implantation and pregastrulation development when further cultured in an in vitro 3D culture system. In summary, our study provides an alternative strategy to generate human blastoids and offers insights into human early embryogenesis by modeling peri- and postimplantation development in vitro.

Bilineage embryo-like structure from EPS cells can produce live mice with tetraploid trophectoderm

Self-organized blastoids from extended pluripotent stem (EPS) cells possess enormous potential for investigating postimplantation embryo development and related diseases. However, the limited ability of postimplantation development of EPS-blastoids hinders its further application. In this study, single-cell transcriptomic analysis indicated that the "trophectoderm (TE)-like structure" of EPS-blastoids was primarily composed of primitive endoderm (PrE)-related cells instead of TE-related cells. We further identified PrE-like cells in EPS cell culture that contribute to the blastoid formation with TE-like structure. Inhibition of PrE cell differentiation by inhibiting MEK signaling or knockout of Gata6 in EPS cells markedly suppressed EPS-blastoid formation. Furthermore, we demonstrated that blastocyst-like structures reconstituted by combining the EPS-derived bilineage embryo-like structure (BLES) with either tetraploid embryos or tetraploid TE cells could implant normally and develop into live fetuses. In summary, our study reveals that TE improvement is critical for constructing a functional embryo using stem cells in vitro.

Progress of research on chromosomal mosaicism embryos / 中华医学遗传学杂志

Chromosomal mosaicism (CM) is a common phenomenon in preimplantation genetic testing (PGT). In embryos with CM, genetic contents of trophoblastic ectodermal (TE) cells may be different from that of the inner cell mass (ICM) which will develop into the fetus. Embryos with low mosaic proportion could give rise to healthy live births after transplantation, but are accompanied with high pregnancy risks such as high abortion rate. In order to provide a more comprehensive understanding for CM embryos, this article has systematically summarized the recent progress of research on the definition, mechanism, classification, PGT techniques, self-correction mechanism, transplantation outcome and treatment principles for CM embryos.

Application of single sperm sequencing for the preimplantation genetic testing of a Chinese family affected with Spinal muscular atrophy / 中华医学遗传学杂志

OBJECTIVE@#To assess the value of single sperm sequencing in preimplantation genetic testing for monogenic disease (PGT-M).@*METHODS@#A Chinese couple with two children whom had died of Spinal muscular atrophy (SMA) and attended the Jiangxi Provincial Maternal and Child Health Care Hospital in June 2020 was selected as the subject. Eleven single sperm samples were isolated by mechanical immobilization and subjected to whole genome amplification. Real-time PCR and Sanger sequencing were used to detect the SMN1 variants in the single sperm samples. Genomic DNA of the wife, her parents and the husband, as well as one single sperm sample harboring the SMN1 variant and two single sperm samples without the variant were used for the linkage analysis. Targeted capture and high-throughput sequencing were carried out to test 100 single nucleotide polymorphisms distributed within 2 Mb up- and downstream the variant site. The haplotypes linked with the SMN1 variants were determined by linkage analysis. Blastocyst embryos were harvested after fertilizing by intracytoplasmic sperm injection. Cells from the trophoblasts of each embryo were biopsied and subjected to whole genome amplification and targeted capture and high-throughput sequencing to determine their carrier status. Chromosomal aneuploidy of wild-type embryos was excluded. An euploid embryo of high quality was transferred. Amniotic fluid sample was taken at 18 weeks of gestation to confirm the status of the fetus.@*RESULTS@#Genetic testing showed that the couple both had deletion of exons 7 ~ 8 of the SMN1 gene. The wife has inherited the deletion from her father, while the husband was de novo. The haplotypes of the husband were successfully constructed by single sperm sequencing. Preimplantation genetic testing has indicated that 5 embryos had harbored the heterozygous variant, 4 embryos were of the wild type, among which 3 were euploid. Prenatal diagnosis during the second trimester of pregnancy has confirmed that the fetus did not carry the deletion.@*CONCLUSION@#By single sperm sequencing and PGT-M, the birth of further affected child has been successfully avoided.

Impact of inactivated SARS-CoV-2 vaccination on embryo ploidy: a retrospective cohort study of 133 PGT-A cycles in China

BACKGROUND: Unsubstantiated concerns have been raised on the potential correlation between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and infertility, leading to vaccine hesitancy in reproductive-aged population. Herein, we aim to evaluate the impact of inactivated SARS-CoV-2 vaccination on embryo ploidy, which is a critical indicator for embryo quality and pregnancy chance. METHODS: This was a retrospective cohort study of 133 patients who underwent preimplantation genetic testing for aneuploidy (PGT-A) cycles with next-generation sequencing technology from June 1st 2021 to March 17th 2022 at a tertiary-care medical center in China. Women fully vaccinated with two doses of Sinopharm or Sinovac inactivated vaccines (n = 66) were compared with unvaccinated women (n = 67). The primary outcome was the euploidy rate per cycle. Multivariate linear and logistic regression analyses were performed to adjust for potential confounders. RESULTS: The euploidy rate was similar between vaccinated and unvaccinated groups (23.2 ± 24.6% vs. 22.6 ± 25.9%, P = 0.768), with an adjusted ß of 0.01 (95% confidence interval [CI]: -0.08-0.10). After frozen-thawed single euploid blastocyst transfer, the two groups were also comparable in clinical pregnancy rate (75.0% vs. 60.0%, P = 0.289), with an adjusted odds ratio of 6.21 (95% CI: 0.76-50.88). No significant associations were observed between vaccination and cycle characteristics or other laboratory and pregnancy outcomes. CONCLUSIONS: Inactivated SARS-CoV-2 vaccination had no detrimental impact on embryo ploidy during in vitro fertilization treatment. Our finding provides further reassurance for vaccinated women who are planning to conceive. Future prospective cohort studies with larger datasets and longer follow-up are needed to confirm the conclusion.

First Baby Born in Brazil after Simultaneous Diagnosis through Non-Invasive and Conventional PGT-A / Primeiro bebê nascido no Brasil após diagnóstico simultâneo por PGT-A não-invasivo e convencional

Abstract Non-invasive preimplantation genetic testing for aneuploidies (niPGT-A) aiming to assess cell-free embryonic DNA in spent culturemedia is promising, especially because it might overcome the diminished rates of implantation caused by the inadequate performance of trophectoderm (TE) biopsy. Our center is part of the largest study to date assessing the concordance between conventional PGT-A and niPGT-A, and we report here the delivery of the first baby born in Brazil using niPGT-A. The parents of the baby were admitted to our center in 2018. They did not present history of infertility, and they were interested in using in vitro fertilization (IVF) and PGT-A in order to avoid congenital anomalies in the offspring. A total of 11 (3 day-5 and 8 day-6) expanded blastocysts were biopsied, and the spent culture media (culture from day-4 to day-6) from 8 day-6 blastocysts were collected for niPGT-A. Overall, 7 embryos yielded informative results for trophectoderm (TE) and media samples. Among the embryos with informative results, 5 presented concordant diagnosis between conventional PGTA and niPGT-A, and 2 presented discordant diagnosis (1 false-positive and one falsenegative). The Blastocyst 4, diagnosed as 46, XY by both niPGT-A and conventional PGTA, was warmed up and transferred, resulting in the birth of a healthy 3.8 kg boy in February 2020. Based on our results and the recent literature, we believe that the safest current application of niPGT-A would be as a method of embryo selection for patients without an indication for conventional PGT-A. The approximate 80% of reliability of niPGT-A in the diagnosis of ploidy is superior to predictions provided by other noninvasive approaches like morphology and morphokinetics selection.

Resumo Abordagens para o teste genético pré-implantacional não-invasivo para aneuploidias (non-invasive preimplantation genetic testing for aneuploidies, niPGT-A, em inglês) com o objetivo de avaliar o DNA embrionário livre são promissoras, especialmente porque estas podem reverter as menores taxas de implantação causadas por inadequada biópsia de trofectoderma (TE). Nesse contexto, nosso centro é parte do maior estudo atual que avalia as taxas de concordância entre PGT-A convencional e niPGT-A, e relatamos aqui o nascimento do primeiro bebê brasileiro após niPGT-A. Os pais do bebê foram admitidos no nosso centro em 2018. Eles não apresentavam histórico de infertilidade, e estavam interessados em utilizar os tratamentos de fertilização in vitro (FIV) e PGT-A para evitar anomalias congênitas na progênie.Umtotal de 11 blastocistos expandidos (3 do dia-5 e 8 do dia-6) foram submetidos a biópsia, e os meios de cultivo condicionados (cultivo do dia-4 ao dia-6) de 8 blastocistos do dia-6 foram coletados para niPGT-A. No total, resultados informativos para as amostras de TE e dos meios foram obtidos para sete embriões. Entre os embriões com resultado informativo, 5 apresentaram diagnóstico concordante entre PGT-A convencional e niPGT-A, e 2 apresentaram diagnóstico discordante (1 falso positivo e 1 falso negativo). O Blastocisto 4, diagnosticado como 46, XY por ambos niPGT-A e PGT-A convencional, foi desvitrificado e transferido, o que resultou no nascimento de ummenino saudável, que pesava 3,8 kg, em fevereiro de 2020. Com base em nossos resultados e literatura contemporânea, acreditamos que a aplicação atualmais segura do niPGT-A seria como método de seleção embrionária para pacientes sem indicação ao PGT-A convencional. A confiabilidade aproximada de 80% do niPGT-A para determinação da ploidia ainda é superior àquela obtida com abordagens não invasivas, como seleção morfológica ou morfocinética.

Morphometry of bovine blastocysts produced in vitro in culture media with antioxidants cysteamine or oily extract of Lippia origanoides / [Morfometria de blastocistos bovinos produzidos in vitro em meio de cultura com antioxidantes cisteamina ou extrato oleoso de Lippia origanoides]

This study aimed to evaluate the ultrastructural morphometry of bovine embryos produced in vitro grown at different concentrations of antioxidants. After in vitro maturation and fertilization, the presumptive zygotes were assigned into five treatments. T1) without the addition of any antioxidants (negative control); T2) addition of 50µM/mL cysteamine; and T3, T4 and T5) adding 2.5µg/mL, 5.0µg/mL or 10.0µg/mL of the antioxidants derived from the oily extract from Lippia origanoides, respectively. On D7 of culture, the embryos in the blastocyst stage were fixed and prepared for electron transmission microscopy. These were evaluated for the proportion of cytoplasm-to-nucleus, cytoplasm-to-mitochondria, cytoplasm-to-vacuoles, cytoplasm-to-autophagic vacuoles and cytoplasm-to-lipid droplets. Blastocysts cultured in media containing oily extract of Lippia origanoides presented morphological characteristics such as high cell:mitochondria ratio and low cell:vacuoles and cell:autophagic vacuole ratio, possibly been morphological indicators of embryonic quality. Inner cell mass (ICM) from blastocysts cultured in media without any antioxidants had the highest cell:vacuole ratio. Similar results were found in the trophectoderm (TE) cells of blastocysts from treatment 2. Embryo culture media supplemented with antioxidants derived from Lippia origanoides oil produced embryos with a higher cytoplasmic proportion of organelles, such as mitochondria. Also, treatments without any antioxidants or with the addition of cysteamine presented cytoplasmic vacuolization, a characteristic related to production of poor-quality embryos.(AU)

Este estudo teve como objetivo avaliar a morfometria ultraestrutural de embriões bovinos produzidos in vitro e cultivados em diferentes concentrações de antioxidantes. Após a maturação e a fertilização in vitro, os possíveis zigotos foram divididos em cinco tratamentos: T1) sem adição de antioxidantes (controle negativo); T2) adição de 50µM/mL de cisteamina; e T3, T4 e T5) adição de 2,5µg/mL, 5,0µg/mL ou 10,0µg/mL dos antioxidantes derivados do extrato oleoso de Lippia origanoides, respectivamente. No D7 de cultivo, os embriões em estágio de blastocisto foram fixados e preparados para microscopia eletrônica de transmissão. Estes foram avaliados para a proporção entre citoplasma e núcleo, citoplasma e mitocôndria, citoplasma e vacúolos, citoplasma e vacúolos autofágicos e citoplasma e gotículas lipídicas. Blastocistos cultivados em meio contendo extrato oleoso de Lippia origanoides apresentaram características morfológicas como alta relação célula:mitocôndria e baixa relação célula:vacúolos e célula:vacúolo autofágico, possíveis indicadores morfológicos de qualidade embrionária. A massa celular interna (MCI) de blastocistos cultivados em meio sem quaisquer antioxidantes teve a maior razão célula:vacúolo. Resultados semelhantes foram encontrados nas células do trofectoderma (TE) de blastocistos do tratamento 2. Portanto, o meio de cultivo embrionário suplementado com antioxidantes derivados do óleo de Lippia origanoides produziu embriões com maior proporção citoplasmática de organelas, como mitocôndrias. Além disso, tratamentos sem antioxidantes ou com adição de cisteamina apresentaram vacuolização citoplasmática, característica relacionada à produção de embriões de baixa qualidade.(AU)

Effects of hydrosalpinx on endometrial implantation failures: evaluating salpingectomy in women undergoing in vitro fertilization / Efeitos do hydrosalpinx no falho de implantação endometrial: Avaliar a salpingectomia nas mulheres em curso de fertilização in vitro

Abstract Hydrosalpinx is a disease characterized by the obstruction of the salpinx, with progressive accumulation in the shape of a fluid-filled sac at the distal part of the tuba uterina, and closed to the ovary. Women with hydrosalpinges have lower implantation and pregnancy rates due to a combination of mechanical and chemical factors thought to disrupt the endometrial environment. Evidence suggests that the presence of hydrosalpinx reduces the rate of pregnancy with assisted reproductive technology. The main aim of the present is review to make an overview of the possible effects of hydrosalpinx on in vitro fertilization (IVF).We conducted a literature search on the PubMed, Ovid MEDLINE, and Google Scholar data bases regarding hydrosalpinx and IVF outcomes. Hydrosalpinx probably has a direct toxic effect on sperm motility and on the embryos. In addition, the increasing liquid inside the salpinges could alter the mechanisms of endometrial receptivity. The window of endometrial receptivity is essential in the implantation of blastocysts, and it triggers multiple reactions arising from the endometrium as well as the blastocysts. Hydrosalpinx could influence the expression of homeobox A10 (HOXA10) gene, which plays an essential role in directing embryonic development and implantation. Salpingectomy restores the endometrial expression of HOXA10; therefore, it may be one mechanism by which tubal

The effect of melatonin on in vitro maturation fertilization and early embryo development of mouse oocytes and expression of HMGB1 gene in blastocysts

Antioxidants are commonly used for maturation, fertilization and early development of embryos. Melatonin as an antioxidant have been recently proven to be useful for the assisted reproductive technology. In the present study, we evaluated the roles of melatonin in the in vitro maturation, fertilization, development and also the gene expression of high mobility group box-1 (HMGB1) in the blastocysts. The immature oocytes of BDF1 mice were transferred to the media containing different doses of melatonin (10-6, 10-9, 10-12 M). The blastocysts that developed under in vitro fertilization from each group were stained to determine the cell number of embryos and analyzed to determine the expression level of HMGB1 by real-time PCR. The most effective doses of melatonin for maturation of oocytes were 10-6 and 10-12M (P<0.05). Fertilization rate, early development and the cell number of blastocysts were significantly higher in the group that treated with 10-12 M of melatonin comparing to the other groups. The HMGB1 expression decreased in groups that treated with 10-6M and 10-9M of melatonin and increased in the group that treated with 10-12 M of melatonin, but did not show a significant difference (p˃0.05). From the results, it may be concluded that the melatonin could be effective when the embryos undergo maturation, fertilization and early developmental processes. The HMGB1 expression, as a marker of early development in mice embryos, increased in the groups that treated with low doses of melatonin

Preimplantation genetic testing for a couple where the husband is affected by osteogenesis imperfecta combined with balanced translocation using karyomapping technique / 中华医学遗传学杂志

OBJECTIVE@#To carry out preimplantation genetic testing (PGT) for a couple where the husband was affected by osteogenesis imperfecta combined with balanced translocation using the karyomapping technique.@*METHODS@#Blastocysts were detected using karyomapping, the carrier status of COL1A1 c.760G>A (p.Gly254Arg) variant and the carrier status of the translocated chromosome were analyzed simultaneously.@*RESULTS@#For a total of 10 blastocysts, two euploid blastocysts were found to not carry the COL1A1 c.760G>A (p.Gly254Arg) variant but a balanced translocation. After transplanting one of the blastocysts, clinical pregnancy was achieved. Amniocentesis at 18th gestational week and prenatal genetic testing was in keeping with the result of PGT.A healthy female was born at 40+4 weeks gestation.@*CONCLUSION@#For patients simultaneously carrying genetic variant and balanced chromosomal translocation, PGT can be performed with efficiency by the use of karyomapping method.

Application of mapping allele with resolved carrier status technique for preimplantation genetic testing in carriers with balanced chromosomal translocations / 中华医学遗传学杂志

OBJECTIVE@#To assess the application value of mapping allele with resolved carrier status (MaReCs) technique for preimplantation genetic testing (PGT).@*METHODS@#The characteristics of MaReCs for PGT and outcome of patients were retrospectively analyzed.@*RESULTS@#Compared with those who could not use the technique, carriers who have used the MaReCs technique were younger, had significantly higher level of anti-Mullerian hormone, more antral follicles, occytes, mature occytes, biopsied embryos and euploid embryos, and lower risks for de novo chromosomal abnormality (P 0.05). Carriers undergoing MaReCs test could preferentially select embryos with normal chromosome structures for the transfer.@*CONCLUSION@#Application of MaReCs has a prerequisite for having a minimum number of occytes and biopsied embryos and using discarded embryos sometimes. MaReCs is efficient for the detection of carrier status of embryos and attaining higher rate of pregnancy and live birth, which can significantly improve the outcome for couples carrying chromosomal translocations.

Design and experiment of online monitoring system for long-term culture of embryo / 生物医学工程学杂志

In the study of embryo development process, the morphological features at different stages are essential to evaluate developmental competence of the embryo, which can be used to optimize and improve the system for

Correlation between insemination dose and bovine sperm traits on the in vitro embryo production outcomes / Correlação da dose inseminante e características do sêmen bovino no sucesso da produção in vitro de embriões

In the present study we aimed to test the best insemination dose for in vitro embryo production (IVEP) and to correlate sperm traits in bovine. In vitro matured oocytes were inseminated with three different sperm concentrations of the same bull: G1 (1*106), G2 (2*106) and G3 (4*106) sperm/mL. At 18 h post-insemination (hpi), presumptive zygotes [G1 (n=114), G2 (n=139) and G3 (n=136)] were stained to evaluate the pronuclei numbers, or continued to in vitro culture [G1 (n=102), G2 (n=111) and G3 (n=106)]. Sperm kinetics were analyzed using Computer-Assisted Semen Analysis (CASA). Sperm plasma membrane, acrosome integrity and mitochondrial activity were analyzed using fluorescent probes. In vitro fertilization (IVF) and IVEP data were compared using chi-square (P<0.05) and correlated with CASA and fluorescence data using Person Correlation (P<0.05). The IVF efficiency, cleavage and total blastocyst rates did not show any significant difference (P>0.05) among the groups. In G3, the polyspermy rate was the highest (7.4%; P<0.05) without difference (P>0.05) between G1 (0%) and G2 (0%). In G1, the early blastocyst rate was the highest (7.8%; P<0.05), without significant difference (P>0.05) between G2 (1.8%) and G3 (0.9%). The IVF efficiency and total blastocyst rates were positively correlated with curvilinear velocity (VCL) (r≃+1; P<0.05). We concluded that the reduction of insemination dose may negatively affect embryo development and VCL may be used as a parameter to improve the IVEP outcomes.

O objetivo deste estudo foi testar a melhor dose inseminante para a produção de embriões in vitro (IVEP) e sua correlação com as características espermáticas na espécie bovina. Oócitos maturados in vitro foram inseminados com três concentrações diferentes de espermatozoides de único touro: G1 (1*106), G2 (2*106) e G3 (4*106) espermatozoides/mL. Às 18h pós-inseminação (hpi), os presumíveis zigotos [G1 (114), G2 (139) e G3 (136)] foram corados para avaliar o número de pronúcleos, ou continuaram para o cultivo in vitro [G1 (102), G2 (111) e G3 (106)]. Os parâmetros da cinética espermática foram analisados usando o Computer-Assisted Semen Analysis (CASA). A integridade de membrana plasmática espermática, acrossomal e a atividade mitocondrial foram analisadas usando sondas fluorescentes. Os dados da fertilização in vitro (FIV) e IVEP foram comparadas com qui-quadrado (P=0,05) e correlacionados com dados de CASA e Fluorescência usando Correlação de Pearson (r=±1; P<0,05). A eficiência da FIV, taxas de clivagem e blastocisto total não mostraram diferença significativa (P>0,05) entre os grupos. Em G3, a taxa de polispermia foi a maior (7,4%; P<0,05), sem diferença (P>0,05) entre G1 (0%) e G2 (0%). Em G1, a taxa de blastocisto inicial foi a maior (7,8%; P<0,05), sem apresentar diferença significativa (P>0,05) com G2 (1,8%) e G3 (0,9%). A eficiência de FIV e a taxa de blastocisto total foram positivamente correlacionadas com velocidade curvilinear (VCL) (P<0,05). Concluímos que a dose inseminante reduzida pode negativamente afetar o desenvolvimento embrionário e VCL pode ser usada como parâmetro para melhorar os resultados da PEIV.

Correlation between insemination dose and bovine sperm traits on the in vitro embryo production outcomes / Correlação da dose inseminante e características do sêmen bovino no sucesso da produção in vitro de embriões

In the present study we aimed to test the best insemination dose for in vitro embryo production (IVEP) and to correlate sperm traits in bovine. In vitro matured oocytes were inseminated with three different sperm concentrations of the same bull: G1 (1*106 ), G2 (2*106 ) and G3 (4*106 ) sperm/mL. At 18 h post-insemination (hpi), presumptive zygotes [G1 (n=114), G2 (n=139) and G3 (n=136)] were stained to evaluate the pronuclei numbers, or continued to in vitro culture [G1 (n=102), G2 (n=111) and G3 (n=106)]. Sperm kinetics were analyzed using Computer-Assisted Semen Analysis (CASA). Sperm plasma membrane, acrosome integrity and mitochondrial activity were analyzed using fluorescent probes. In vitro fertilization (IVF) and IVEP data were compared using chisquare (P0.05) among the groups. In G3, the polyspermy rate was the highest (7.4%; P0.05) between G1 (0%) and G2 (0%). In G1, the early blastocyst rate was the highest (7.8%; P0.05) between G2 (1.8%) and G3 (0.9%). The IVF efficiency and total blastocyst rates were positively correlated with curvilinear velocity (VCL) (r≃+1; P<0,05). We concluded that the reduction of insemination dose may negatively affect embryo development and VCL may be used as a parameter to improve the IVEP outcomes.

O objetivo deste estudo foi testar a melhor dose inseminante para a produção de embriões in vitro (IVEP) e sua correlação com as características espermáticas na espécie bovina. Oócitos maturados in vitro foram inseminados com três concentrações diferentes de espermatozoides de único touro: G1 (1*106 ), G2 (2*106 ) e G3 (4*106 ) espermatozoides/mL. Às 18 h pós-inseminação (hpi), os presumíveis zigotos [G1 (114), G2 (139) e G3 (136)] foram corados para avaliar o número de pronúcleos, ou continuaram para o cultivo in vitro [G1 (102), G2 (111) e G3 (106)]. Os parâmetros da cinética espermática foram analisados usando o ComputerAssisted Semen Analysis (CASA). A integridade de membrana plasmática espermática, acrossomal e a atividade mitocondrial foram analisadas usando sondas fluorescentes. Os dados da fertilização in vitro (FIV) e IVEP foram comparadas com qui-quadrado (P=0,05) e correlacionados com dados de CASA e Fluorescência usando Correlação de Pearson (r=±1; P0,05) entre os grupos. Em G3, a taxa de polispermia foi a maior (7,4%; P0,05) entre G1 (0%) e G2 (0%). Em G1, a taxa de blastocisto inicial foi a maior (7,8%; P0,05) com G2 (1,8%) e G3 (0,9%). A eficiência de FIV e a taxa de blastocisto total foram positivamente correlacionadas com velocidade curvilinear (VCL) (P<0,05). Concluímos que a dose inseminante reduzida pode negativamente afetar o desenvolvimento embrionário e VCL pode ser usada como parâmetro para melhorar os resultados da PEIV.

Interacción endometrio trofoblasto, en la implantación humana: revisión de la literatura / Endometrium-trophoblast interaction in human implantation: review of literature

Un embarazo exitoso requiere de una serie de interacciones mediadas por factores hormonales, moleculares y fenómenos de inmunomodulación. Una de estas interacciones es la que ocurre entre el endometrio y el blastocito, previo y durante el proceso de implantación. El objetivo de esta revisión bibliográfica es complementar lo descrito en la literatura clásica de embriología humana sobre interacción de endometrio-blastocito. La búsqueda bibliográfica se realizó en la base de datos MEDLINE usando los términos en inglés "implantation", "endometrium" y "embryo"; además se realizó una búsqueda manual, que incluyó artículos de revistas no indexadas, libros de texto y atlas. Se consideraron criterios de inclusión y exclusión para la selección de los artículos y otros recursos bibliográficos. Entre los criterios de inclusión se consideraron estudios realizados en humanos, artículos de revisión y experimentación, publicados en los últimos 5 años. Como criterios de exclusión se consideraron artículos que utilizaran animales, estudios sobre fertilidad in vitro, patologías asociadas y artículos no relacionados al tema. Una vez completada la selección, se examinaron los textos completos, en los cuales se aplicaron nuevamente los criterios de exclusión. La búsqueda arrojó un total de 560 artículos, cuyo análisis de los títulos y resúmenes resultó en 475 trabajos excluidos, a partir de los diferentes criterios de exclusión antes descritos. Por lo tanto, se obtuvieron 85 artículos, en los cuales se realizó el análisis del texto completo. De estos artículos, se obtuvieron un total de 34 estudios y los contenidos seleccionados en esta revisión fueron: Endometrio, Interacción endometrio trofoblasto, Aposición, Adhesión y Migración-Invasión. Durante la implantación se genera una interacción entre el endometrio y el trofoblasto, con la participación de moléculas reguladoras de proliferación y diferenciación, como factores hormonales, moleculares y de expresión génica. Sin embargo, los mecanismos específicos de acción e interacción deben continuar siendo investigados, para responder interrogantes en el ámbito del crecimiento y desarrollo humano.

A successful pregnancy requires a series of interactions, mediated by hormonal, molecular and immunomodulation phenomena. One of these interactions is between the endometrium and the blastocyst, before and during the implantation process. The objective of this literature review is to complement what is described in the classic human embryology literature on endometrial-blastocyst interaction. The bibliographic search was carried out in the MEDLINE database using the terms "implantation", "endometrium" and "embryo", and a manual search was carried out, which included articles from non-indexed journals, textbooks and atlases. Inclusion and exclusion criteria were considered for the selection of articles and other bibliographic resources, including human studies, review and experimentation articles, published in the last 5 years. Articles with animals as experimental subjects, in vitro fertility studies, associated pathologies and articles not related to the subject were excluded. When the selection was completed, the complete texts were examined, in which the exclusion criteria were applied again The search yielded a total of 560 articles, whose analysis of titles and abstracts resulted in 475 excluded works, in relation to different exclusion criteria described above. Therefore, 85 articles were obtained, in which the complete text analysis was performed. From these articles, a total of 34 studies were obtained and the contents selected in this review were: Endometrium, Endometrium trophoblast, Aposition, Adhesion and Migration-Invasion. During the implantation, aninteraction between the endometrium and the trophoblast is generated, with the participation of regulatory molecules of proliferation and differentiation, such as hormonal, molecular and gene expression factors. However, the specific mechanisms of action and interaction must continue to be investigated, to answer questions in the field of human growth and development.

Correlation between Morphologic Grading and Euploidy Rates of Blastocysts, and Clinical Outcomes in In Vitro Fertilization Preimplantation Genetic Screening

BACKGROUND: The standard morphological evaluation has been widely used for embryo selection, but it has limitations. This study aimed to investigate the correlation between morphologic grading and euploidy rate of in vitro fertilization (IVF) preimplantation genetic screening (PGS) and compare the pregnancy rates in young and old ages. METHODS: This is a retrospective study using the medical records of patients who underwent IVF procedures with PGS between January 2016 and February 2017 in a single center. The embryo grades were categorized into 4 groups: excellent, good, fair, and poor. Basic characteristics, euploidy rates, clinical pregnancy (CP) rates and ongoing pregnancy rates were analyzed. RESULTS: The excellent group had significantly higher rate of euploid embryos than fair group (47.82% vs. 29.33%; P = 0.023) and poor group (47.82% vs. 29.60%; P = 0.005). When the four groups were recategorized into two groups (excellent and good vs. fair and poor), they also showed significant difference in euploidy rates (44.52% vs. 29.53%; P = 0.002). When the patients were divided into two groups by age 35, the CP rates for those under and over 35 years old were 44.74% and 47.83%, respectively, which showed no significant difference. CONCLUSION: The significant differences among the euploidy rates of different morphologic embryo grades demonstrated the positive correlations between the morphologic grading of the embryo and the euploidy rate of PGS. Additionally, there was no significant difference between the younger and older patients' CP rates. These findings emphasize the fact that old age patients might benefit from PGS whatever the indication of PGS is.

Light-induced injury in mouse embryos revealed by single-cell RNA sequencing

BACKGROUND: Light exposure is a common stress factor in in vitro manipulation of embryos in the reproductive center. Many studies have shown the deleterious effects of high-intensity light exposure in different animal embryos. However, no transcriptomic studies have explored the light-induced injury and response in preimplantation embryos. RESULTS: Here, we adopt different time-courses and illumination intensities to treat mouse embryos at the 2-cell stage and evaluate their effects on blastulation. Meanwhile, single-cell transcriptomes from the 2-cell to blastocyst stage were analyzed after high-intensity light exposure. These data show that cells at each embryonic stage can be categorized into different light conditions. Further analyses of differentially expressed genes and GO terms revealed the light-induced injury as well as the potential repair response after high-intensity lighting. Maternal-to-zygote transition is also affected by the failure to remove maternal RNAs and deactivate zygotic genome expression. CONCLUSION: Our work revealed an integrated response to high-intensity lighting, involving morphological changes, long-lasting injury effects, and intracellular damage repair mechanisms.

Growth differentiation factor 9 and cumulus cell supplementation in in vitro maturation culture media enhances the viability of human blastocysts / 대한생식의학회지

OBJECTIVE: In vitro maturation (IVM) of immature oocytes can be useful for some infertile patients. In IVM programs, the rates of embryo formation and pregnancy are low. Therefore, it is essential to recognize the main factors involved in regulating oocyte maturation in vitro. The purpose of this study was to investigate the effects of growth differentiation factor 9 (GDF9) and cumulus cell (CC) supplementation in IVM medium on the rates of embryo formation and viability of human blastocysts.METHODS: A total of 80 germinal vesicle oocytes from stimulated cycles underwent an IVM program. The oocytes were divided into four groups, where group I consisted of IVM media only and served as the control, group II consisted of IVM+CCs, group III consisted of IVM+GDF9 (200 ng/mL), and group IV consisted of IVM+CCs+GDF9 (200 ng/mL). Intracytoplasmic sperm injection was performed on the IVM oocytes, and the cleavage embryos that were generated were vitrified. Following thawing, the embryos were cultured for 3 additional days, and the viability rates of the developed blastocysts were determined.RESULTS: The maturation rate of the oocytes did not differ significantly across the four groups. The fertilization rate in group II was significantly higher than that in the control group (76.5% vs. 46.2%). Embryo formation was significantly more frequent in all experimental groups than in the control group, while blastocyst formation did not show significant differences in the three experimental groups compared to the control. The mean viability rates in groups II, III, and IV were 58.16%, 55.91%, and 55.95%, respectively, versus 37.78% in the control group (p<0.05).CONCLUSION: Supplementation of IVM culture media with GDF9 and CCs enhanced the fertilization, embryo formation, and viability rates of blastocysts generated from vitrified cleavage embryos.

Effects of dynamic oxygen concentrations on the development of mouse pre- and peri-implantation embryos using a double-channel gas supply incubator system / 대한생식의학회지

OBJECTIVE: We aimed to evaluate the effects of different oxygen conditions (20% [high O₂], 5% [low O₂] and 5% decreased to 2% [dynamic O₂]) on mouse pre- and peri-implantation development using a novel double-channel gas supply (DCGS) incubator (CNC Biotech Inc.) to alter the oxygen concentration during in vitro culture.METHODS: The high-O₂ and low-O₂ groups were cultured from the one-cell to the blastocyst stage under 20% and 5% oxygen concentrations, respectively. In the dynamic-O₂ group, mouse embryos were cultured from the one-cell to the morula stage under 5% O₂ for 3 days, followed by culture under 2% O₂ to the blastocyst stage. To evaluate peri-implantation development, the blastocysts from the three groups were individually transferred to a fibronectin-coated dish and cultured to the outgrowth stage in droplets.RESULTS: The blastocyst formation rate was significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The total cell number was significantly higher in the dynamic-O₂ group than in the low-O₂ and high-O₂ groups. Additionally, the apoptotic index was significantly lower in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group. The trophoblast outgrowth rate and spread area were significantly higher in the low-O₂ and dynamic-O₂ groups than in the high-O₂ group.CONCLUSION: Our results showed that a dynamic oxygen concentration (decreasing from 5% to 2%) had beneficial effects on mouse pre- and peri-implantation development. Optimized, dynamic changing of oxygen concentrations using the novel DCGS incubator could improve the developmental competence of in vitro cultured embryos in a human in vitro fertilization and embryo transfer program.