Embryo Viability Research Articles

Adding a ketogenic dietary intervention to IVF treatment in patients with polycystic ovary syndrome improves implantation and pregnancy

Patients with polycystic ovary syndrome (PCOS) on a high-carbohydrate diet intrinsically suffer from exacerbated glucotoxicity, insulin resistance (IR), and infertility. Lowering the carbohydrate content has improved fertility in patients with IR and PCOS; however, the effects of a well-controlled ketogenic diet on IR and fertility in PCOS patients undergoing in vitro fertilization (IVF) have not been reported. Twelve PCOS patients with a previous failed IVF cycle and positive for IR (HOMA1-IR>1.96) were retrospectively evaluated. Patients followed a ketogenic diet (50 g of total carbohydrates/1800 calories/day). Ketosis was considered when urinary concentrations were > 40 mg/dL. Once ketosis was achieved, and IR diminished, patients underwent another IVF cycle. The nutritional intervention lasted for 14 ± 11 weeks. Carbohydrate consumption decreased from 208 ± 50.5 g/day to 41.71 ± 10.1 g/day, which resulted in significant weight loss (−7.9 ± 1.1 kg). Urine ketones appeared in most patients within 13.4 ± 8.1 days. In addition, there was a decrease in fasting glucose (−11.4 ± 3.5 mg/dl), triglycerides (−43.8 ± 11.6 mg/dl), fasting insulin (−11.6 ± 3.7 mIU/mL), and HOMA-IR (−3.28 ± 1.27). All patients underwent ovarian stimulation, and compared to the previous cycle, there was no difference in oocyte number, fertilization rate, and viable embryos produced. However, there was a significant improvement in the implantation (83.3 vs. 8.3 %), clinical pregnancy (66.7 vs. 0 %), and ongoing pregnancy/live birth rates (66.7 vs. 0 %). Here, restriction in carbohydrate consumption in PCOS patients induced ketosis, improved key metabolic parameters, and decreased IR. Even though this did not affect oocyte or embryo quality or quantity, the subsequent IVF cycle significantly improved embryo implantation and pregnancy rates.

Using skin mucus for the identification of ovulation biomarkers in North American Atlantic salmon (Salmo salar)

In Maine, North American Atlantic salmon production has experienced a 20% decrease in eye-up eggs, the point of embryo development where the black eye spot is visible. The maternal endocrine environment is suggested to be an important factor for ovulation and viable embryos but needs to be further investigated. Combining new sampling matrices (skin mucus) and advanced technologies (liquid chromatography tandem mass spectrometry (LC-MS/MS)) will advance the knowledge of the endocrine status in reproductively mature North American Atlantic salmon. The objectives of this study were to 1) identify mucus as a viable matrix to measure steroid hormones, 2) quantify steroid hormone profile of North American Atlantic salmon during ovulation and 3) compare hormone profiles of salmon with high and low eye-up rates. Mucus and plasma were collected from sexually mature female North American Atlantic salmon (n = 30). A group of females were sampled pre-ovulation (n = 9) and a separate group post-ovulation (n = 21) then analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS). Fish collected post-ovulation were slotted into groups based on eye-up rate, fish with ≥70% eye-up rate (high eye-up, n = 5) and fish with ≤70% eye up rate (low eye-up, n = 16). In mucus allopregnanolone (p = 0.01), 11-deoxycorticosterone (p = 0.05) and 11-deoxycortisol (p = 0.01) were significantly higher after ovulation. In plasma, allopregnanolone was significantly lower after ovulation (p = 0.01 and 17α, 20β-hydroxyprogesterone was significantly elevated (p = 0.05) after ovulation. Fish with a low eye-up rate had elevated mucus concentrations of corticosterone (p = 0.02). While fish with a high eye-up rate had elevated plasma testosterone concentrations (p = 0.04). Circulating androstenedione (r = 0.46, p = 0.03) and testosterone (r = 0.47, p = 0.03) were significantly correlated with eye-up rate. Mucosal concentrations of steroid hormone correlated with circulating concentrations of related steroids and reflect changes in reproductive physiology. The significant changes in mucosal and circulating steroid concentrations of the 5α reduced pregnane, allopregnanolone suggests a role of 5α-reduced pregnanes during ovulation in North American Atlantic salmon. To our knowledge this is the first time any 5α-reduced pregnane has been reported in teleosts. Mucosal concentrations of precursor glucocorticoids significantly elevated after ovulation combined with significant correlation with hydroxylated pregnanes suggests a dual mechanism needed for ovulation between glucocorticoids and pregnanes. Additionally, glucocorticoids and androgens appear to influence the viability of fertilized eggs highlighting the need for further research into the role's multiple hormones play in both oocyte maturation and embryo viability.

Embryo biopsy and vitrification applied to a commercial embryo transfer program in Argentina

Use of embryo vitrification (EV) would have multiple advantages in a commercial embryo transfer (ET) program. EV would allow embryos to be transferred so that foals were born in early spring, which is preferred in Argentina due to health problems in foals that are born in late spring-summer. Currently, many high-level Polo mares compete in the spring, and the potential for embryo production from these mares is thus lost. EV would allow embryo storage against future loss or sale of a mare and allow owners to control which embryos were transferred in any given season. EV would also help the ET Center, by spreading work out through the breeding season and simplifying recipient synchronization. To explore the use of EV in our program, we compared pregnancy rates after transfer of vitrified-thawed vs. fresh embryos. Embryos were recovered on Day 7 to 8 post-ovulation from donor mares in our clinical program at Doña Pilar in September 2021 to May 2022 (Season 1) and then vitrified, and in September 2022 to January 2023 (Season 2) and transferred fresh. All embryos were transferred during Season 2. Fresh embryos were either biopsied via micromanipulation for sexing by PCR (BF, n=136) or were not biopsied (client did not request sexing orthe embryo was considered too small to biopsy, <∼300 µm diameter; F, n=62). Vitrified embryos were vitrified using a commercial human kit (CryoTech) after collapse of the blastocoele by micromanipulation, with biopsy (BV, n = 69) or without biopsy (MV, n = 9), or were vitrified without micromanipulation (<∼300 µm diameter; V). To date, the pregnancy rates per transferred embryo were BF 77/109 (70.6%); F 47/59 (79.6%); BV 24/36 (66.7%); MV 4/4 (100%) and V 9/14 (64.2%). There were no significant differences between treatments (Fishers exact test, p > 0.2). We conclude that embryo biopsy did not affect viability of fresh embryos, and that notably, the pregnancy rate was equivalent between fresh biopsied embryos (71%) and vitrified biopsied embryos (67%). The numerically lowest pregnancy rate resulted from embryos vitrified without manipulation. To the best of our knowledge, this is the first report on pregnancy rates of equine embryos vitrified after biopsy. These results indicate that a biopsy and vitrification program is feasible in a commercial embryo transfer center in Argentina. We foresee that in the near future most embryos collected after December 31st in our program will be vitrified and transferred between September and October of the following year.

Vitrification and direct warming in iso-osmotic holding medium of equine in vitro embryos supports competitive pregnancy rates

Improved efficiency of ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) resulted to a steep increase in the number of in vitro produced (IVP) equine embryos worldwide. These IVP blastocysts are routinely cryopreserved and both slow freezing and vitrification result in high pregnancy rates. The use of minimal volume cryodevices and fast, multistep warming protocols can be challenging for veterinary practitioners receiving vitrified embryos, but direct warming in embryo holding medium supports embryo viability (Canesin et al. Theriogenology. 2020;151:151-158). The aim of this study was to compare pregnancy rates in a clinical OPU-ICSI program using a three-step vitrification/warming protocol vs. a commercial vitrification kit and direct warming in embryo holding medium. Embryos were produced in autumn and winter of 2021-2022 by OPU-ICSI (Papas et al. Animals. 2021;11:2004). Day of vitrification (7-12 post ICSI) was similar for both vitrification groups. Blastocysts were vitrified in a minimal volume on a Cryolock (Irvine Scientific) following two methods: (1) a three-step protocol (n=21): holding in basal vitrification medium (BVM; DMEM-F12 with 20% FCS), vitrification in BVM with 1.5M ethylene glycol (5 min), followed by BVM with 7M ethylene glycol and 0.6M galactose (40 s), and warming in warming medium (WM; DPBS with 0.1% glucose,36 mg/L pyruvate, and 0.4% BSA) with 0.3M sucrose (1 min), followed by WM with 0.15M sucrose (5 min) and holding in WM (5 min), all performed at 38.2°C (Choi and Hinrichs. Theriogenology. 2017; 87:48-54); (2) direct warming (n=21): vitrification at 23°C with a commercial VIT-Kit (Minitube, Germany) in VS1 (5 min), VS2 (5 min) and VS3 (40 s), containing increasing concentrations of glycerol and/or ethylene glycol, based on Eldridge-Panuska et al. (Theriogenology. 2005; 63:1308-1319), and direct warming at 38°C for 5 min in 4 ml of Emcare holding medium (Spervital, The Netherlands). For both protocols, warmed embryos were washed four times in Emcare and transferred immediately to a day 4 recipient mare. The effect of vitrification method on pregnancy rate at 14 days and 25 days was determined using binomial logistic regression analyses. Pregnancy rates at 14 and 25 days were respectively 66.7% and 47.6% for the three-step method and 76.2% and 52.4% for the direct warming. No difference was found between the two methods (p=0.496 and p=0.882, respectively). In conclusion, vitrification and warming of IVP blastocysts using commercial media and direct warming supports pregnancy and provides an easy method for embryo warming and transfer by equine veterinary practitioners.

Ablation of ZC3H11A causes early embryonic lethality and dysregulation of metabolic processes

ZC3H11A (zinc finger CCCH domain-containing protein 11A)is a stress-induced mRNA-binding protein required for efficient growth of nuclear-replicating viruses. The cellular functions of ZC3H11A during embryonic development are unknown. Here, we report the generation and phenotypic characterization of Zc3h11a knockout (KO) mice. Heterozygous null Zc3h11a mice were born at the expected frequency without distinguishable phenotypic differences compared with wild-type mice. In contrast, homozygous null Zc3h11a mice were missing, indicating that Zc3h11a is crucial for embryonic viability and survival. Zc3h11a -/- embryos were detected at the expected Mendelian ratios up to late preimplantation stage (E4.5). However, phenotypic characterization at E6.5 revealed degeneration of Zc3h11a -/- embryos, indicating developmental defects around the time of implantation. Transcriptomic analyses documented a dysregulation of glycolysis and fatty acid metabolic pathways in Zc3h11a-/- embryos at E4.5. Proteomic analysis indicated a tight interaction between ZC3H11A and mRNA-export proteins in embryonic stem cells. CLIP-seq analysis demonstrated that ZC3H11A binds a subset of mRNA transcripts that are critical for metabolic regulation of embryonic cells. Furthermore, embryonic stem cells with an induced deletion of Zc3h11a display an impaired differentiation toward epiblast-like cells and impaired mitochondrial membrane potential. Altogether, the results show that ZC3H11A is participating in export and posttranscriptional regulation of selected mRNA transcripts required to maintain metabolic processes in embryonic cells. While ZC3H11A is essential for the viability of the early mouse embryo, inactivation of Zc3h11a expression in adult tissues using a conditional KO did not lead to obvious phenotypic defects.

Assessing the clinical viability of micro 3 pronuclei zygotes.

What is the rate of euploidy and clinical viability of embryos resulting from micro 3 pronuclei zygotes? Retrospective cohort analysis in a single, academic in vitro fertilization (IVF) center from March 2018 to June 2021. Cohorts were separated by fertilization as either a 2 pronuclear zygote (2PN) or micro 3 pronuclear zygote (micro 3PN). PGT-A was performed to identify embryonic ploidy rates in embryos created from micro 3PN zygotes. The clinical outcomes of all transferred euploid micro 3PN zygotes were evaluated from frozen embryo transfer (FET) cycles. During the designated study period, 75,903 mature oocytes were retrieved and underwent ICSI. Of these, 60,161 were fertilized as 2PN zygotes (79.3%) and 183 fertilized as micro 3PN zygotes (0.24%). Of the micro 3PN-derived embryos that underwent biopsy, 27.5% (n=11/42) were deemed euploid by PGT-A, compared to 51.4% (n=12,301/23,923) of 2PN-derived embryos, p=0.06. Four micro 3PN-derived embryos were transferred in subsequent single euploid FET cycles, which includes one live birth and one ongoing pregnancy. Micro 3PN zygotes that develop to the blastocyst stage and meet the criteria for embryo biopsy have the potential to be euploid by preimplantation genetic testing for aneuploidy (PGT-A) and if selected for transfer can achieve a live birth. Although there are a significantly lower number of micro 3PN embryos that make it to blastocyst biopsy, the potential to continue to culture abnormally fertilized oocytes may give these patients a chance at pregnancy that they previously did not have.

Perspective: Can early embryonic losses be reduced in lactating dairy cows?

Perspective: Can early embryonic losses be reduced in lactating dairy cows?

Evidence implicating sequential commitment of the founder lineages in the human blastocyst by order of hypoblast gene activation.

Successful human pregnancy depends upon rapid establishment of three founder lineages: the trophectoderm, epiblast and hypoblast, which together form the blastocyst. Each plays an essential role in preparing the embryo for implantation and subsequent development. Several models have been proposed to define the lineage segregation. One suggests that all lineages specify simultaneously; another favours the differentiation of the trophectoderm before separation of the epiblast and hypoblast, either via differentiation of the hypoblast from the established epiblast, or production of both tissues from the inner cell mass precursor. To begin to resolve this discrepancy and thereby understand the sequential process for production of viable human embryos, we investigated the expression order of genes associated with emergence of hypoblast. Based upon published data and immunofluorescence analysis for candidate genes, we present a basic blueprint for human hypoblast differentiation, lending support to the proposed model of sequential segregation of the founder lineages of the human blastocyst. The first characterised marker, specific initially to the early inner cell mass, and subsequently identifying presumptive hypoblast, is PDGFRA, followed by SOX17, FOXA2 and GATA4 in sequence as the hypoblast becomes committed.

Predicting Cell Cleavage Timings from Time-Lapse Videos of Human Embryos

Assisted reproductive technology is used for treating infertility, and its success relies on the quality and viability of embryos chosen for uterine transfer. Currently, embryologists manually assess embryo development, including the time duration between the cell cleavages. This paper introduces a machine learning methodology for automating the computations for the start of cell cleavage stages, in hours post insemination, in time-lapse videos. The methodology detects embryo cells in video frames and predicts the frame with the onset of the cell cleavage stage. Next, the methodology reads hours post insemination from the frame using optical character recognition. Unlike traditional embryo cell detection techniques, our suggested approach eliminates the need for extra image processing tasks such as locating embryos or removing extracellular material (fragmentation). The methodology accurately predicts cell cleavage stages up to five cells. The methodology was also able to detect the morphological structures of later cell cleavage stages, such as morula and blastocyst. It takes about one minute for the methodology to annotate the times of all the cell cleavages in a time-lapse video.

An Effective Chemical Permeabilization of Silkworm Embryos.

The lipid layer surrounding the vitelline membrane of insect eggs has a critical role in the waterproofing and desiccation resistance of embryos. However, this lipid layer also prevents the flux of chemicals into the embryos, such as cryoprotectants, which are required for successful cryopreservation. The permeabilization studies of silkworm embryos remain insufficient. Therefore, in this study, we developed a permeabilization method to remove the lipid layer in the silkworm, Bombyx mori, and examined factors affecting the viability of dechorionated embryos, including the types and exposure times of chemicals and embryonic stages. Among the chemicals used, hexane and heptane were effective for permeabilization, whereas Triton X-100 and Tween-80 were less effective. Regarding the embryonic stages, there were significant differences between 160 and 166 h after egg laying (AEL) at 25 °C. Consequently, we found that the treatment of 160 AEL embryos with hexane for 30 s was the best condition for the permeability and viability of embryos, in which over 62% of the permeabilized embryos grew up to the second larval instar and their moths could lay fertilized eggs. Our method can be used for various purposes, including permeability investigations using other chemicals and embryonic cryopreservation.

Saṅghabhadra's arguments for the existence of an intermediate state (antarābhava) between biological death and rebirth as translated by Xuanzang (602?–664 ce)

AbstractThe Buddhist doctrine of transmigration (saṃsāra) offers a coherent model of a cycle of existence wherein a sentient being continues throughout life, survives death, traverses the afterlife, and is, sooner or later, reborn, thus inaugurating another lifecycle as a new life-form. The Buddhist tenets of no-self (anātman) and impermanence, however, deny the possibility of a self, soul, or any form of spiritual substance that persists throughout the cycle of transmigration. This article examines the argumentation developed by the Indic Buddhist philosopher, Saṅghabhadra (fl. fifth- century ce), as part of his effort to reconcile the doctrines of no-self and karmic continuity. In his *Nyāyānusāraśāstra and the *Samayapradīpikāśāstra, two seminal, yet vastly understudied, doctrinal treatises of Sarvāstivāda Abhidharma Buddhism that survive only within the translation corpus of the Sinitic scholar-monk Xuanzang (602?–664 ce), Saṅghabhadra defines the antarābhava, the ‘intermediate state of existence’, as the interstitial space and interim time-period existing between the locus wherein the sequentially reproducing psychic constituents of an individual sentient being, including consciousness, desert the no-longer viable body at the moment of biological death, and the locus wherein these psychic constituents become associated with a new gross physical body in the form of a new viable embryo at the moment of rebirth. By instantiating the antarābhava as an actual interval with real extension in space and time, necessarily traversed by the vast majority of sentient beings after dying in order to reach the next gross physical body, Saṅghabhadra provides, for Sarvāstivāda Abhidharma Buddhism, a rigorous account for how karma is transmitted, via the psychic constituents of a sentient being, beyond biological death into future lives, as well as future afterlives.

145 Specific Gravity as an Assessment of Embryonic Viability to Improve Implantation Rates for in Vitro Produced and in Vivo Derived Bovine Embryos

Abstract The objective of this study was to evaluate the ability of a specific gravity chamber (SGC) to identify embryos most likely to result in successful implantation following embryo transfer. In this study, 19 in vitro produced (IVP) and 15 in vivo derived (IVD) Grade bovine embryos were allowed to descend through media in an SGC. Descent time through a 1-cm timing region was recorded, and embryos were retrieved from the chamber and transferred into recipient females or cryopreserved and transferred at a later date. To determine if chamber evaluation had an effect on pregnancy status, 27 IVP and 12 IVD embryos that were not evaluated with the SGC were also transferred alongside project embryos. Pregnancy was determined via transrectal ultrasound palpation and recorded. There was no significant difference in conception rates between embryos evaluated with the SGC and those not, indicating that chamber analysis had no negative impact on viability of both IVP (P = 0.54) and IVD (P = 0.93) embryos. Twenty-two of the 34 total project embryos resulted in successful implantation and pregnancy, with 13 pregnancies (68.4%) by IVP and 9 (60%) by IVD. There was no difference in average descent time of pregnant and non-pregnant embryos for IVP (P = 0.54) or IVD embryos (P = 0.24). When divided into groups according to descent time, 32% of all observations for IVP embryos occurred between 30 to 50 seconds with a 66.7% conception rate, and 42% occurred between 70 to 90 seconds with a 75% conception rate (P = 0.85). For IVD, 60% of all observations occurred between 90 to10 seconds, with a conception rate of 66.7% (P = 0.35). Though not significant, the numeric trends highlighted in these data lend support to previous research utilizing specific gravity. Further research is needed to thoroughly evaluate the potential of this technology as a method of noninvasive assessment of embryo viability.

Clinical safety of bovine intra-ovarian application of allogeneic mesenchymal stem cells

A basic premise of reproductive physiology is that females have a finite and non-renewable stock of germinative cells, which results in a decrease in reproductive capacity over time. For female bovines, a further factor associated with this decrease is follicular puncture (ovum pickup - OPU), a technique widely used for production of embryos in vitro. As such, it is necessary to seek therapeutic or preventive options for fertility problems, and one potential option is treatment with mesenchymal stem cells (MSC), which exercise a paracrine effect in combating inflammatory and degenerative processes. However, as important as evaluating the efficacy of such treatments is an evaluation of safety. In this context, the current study was carried out with the application of 2.5 x 106 allogenic MSC derived from adipose tissue, to the ovarian cortex of healthy nelore (n = 5) and girolando (n = 5) cows. The animals were subsequently evaluated by ultrasonography, clinical examination, number of viable oocytes collected, and rate of embryo production. None of the animals presented any clinical alteration or any alteration on ultrasonography after receiving the MSC. Furthermore, comparison between the number of viable oocytes, embryos produced, and rate of embryo production before and after MSC application did not show a difference. Based on these data, it can be concluded that intraovarian application of 2.5 x 106 adipose-derived MSC is safe, and this technique represents a potential for study as a therapy in cases of ovarian degeneration or lesions.

Human oocyte area is associated with preimplantation embryo usage and early embryo development: the Rotterdam Periconception Cohort

PurposeTo investigate the association between oocyte area and fertilization rate, embryo usage, and preimplantation embryo development in order to establish if oocyte area can be a marker for optimal early embryo development.MethodsFrom 2017 to 2020, 378 couples with an indication for IVF (n = 124) or ICSI (n = 254) were included preconceptionally in the Rotterdam Periconception Cohort. Resulting oocytes (n = 2810) were fertilized and submitted to time-lapse embryo culture. Oocyte area was measured at the moment of fertilization (t0), pronuclear appearance (tPNa), and fading (tPNf). Fertilization rate, embryo usage and quality, and embryo morphokinetics from 2-cell stage to expanded blastocyst stage (t2-tEB) were used as outcome measures in association with oocyte area. Oocytes were termed “used” if they were fertilized and embryo development resulted in transfer or cryopreservation, and otherwise termed “discarded”. Analyses were adjusted for relevant confounders.ResultsOocyte area decreased from t0 to tPNf after IVF and ICSI, and oocytes with larger area shrank faster (β − 12.6 µm2/h, 95%CI − 14.6; − 10.5, p < 0.001). Oocytes that resulted in a used embryo were larger at all time-points and reached tPNf faster than oocytes that fertilized but were discarded (oocyte area at tPNf in used 9864 ± 595 µm2 versus discarded 9679 ± 673 µm2, p < 0.001, tPNf in used 23.6 ± 3.2 h versus discarded 25.6 ± 5.9 h, p < 0.001). Larger oocytes had higher odds of being used (oocyte area at tPNf ORused 1.669, 95%CI 1.336; 2.085, p < 0.001), were associated with faster embryo development up to the morula stage (e.g., t9 β − 0.131 min, 95%CI − 0.237; − 0.025, p = 0.016) and higher ICM quality.ConclusionOocyte area is an informative marker for the preimplantation development of the embryo, as a larger oocyte area is associated with higher quality, faster developing embryos, and higher chance of being used. Identifying determinants associated with oocyte and embryo viability and quality could contribute to improved preconception care and subsequently healthy pregnancies.

Review: Evaluation of bull fertility. Functional and molecular approaches.

With the term "assisted reproduction technologies" in modern cattle farming, one could imply the collection of techniques that aim at the optimal use of bovine gametes to produce animals of high genetic value in a time- and cost-efficient manner. The accurate characterisation of sperm quality plays a critical role for the efficiency of several assisted reproduction-related procedures, such as sperm processing, in vitro embryo production and artificial insemination. Bull fertility is ultimately a collective projection of the ability of a series of ejaculates to endure sperm processing stress, and achieve fertilisation of the oocyte and production of a viable and well-developing embryo. In this concept, the assessment of sperm functional and molecular characteristics is key to bull fertility diagnostics and prognostics. Among others, functional features linked to sperm plasma membrane, acrosome and DNA integrity are usually assessed as a measure of the ability of sperm to express the phenotypes that will allow them to maintain their homeostasis and orchestrate-in a strict temporal manner-the course of events that will enable the delivery of their genetic content to the oocyte upon fertilisation. Nevertheless, measures of sperm functionality are not always adequate indicators of bull fertility. Nowadays, advancements in the field of molecular biology have facilitated the profiling of several biomolecules in male gametes. The molecular profiling of bovine sperm offers a deeper insight into the mechanisms underlying sperm physiology and, thus, can reveal novel candidate markers for bull fertility prognosis. In this review, the importance of three organelles (the nucleus, the plasma membrane and the acrosome) for the characterisation of sperm fertilising capacity and bull fertility is discussed at functional and molecular levels. In particular, information about sperm head morphometry, chromatin structure, viability as well as the ability of sperm to capacitate and undergo the acrosome reaction are presented in relation to the cryotolerance of male gametes and bull fertility. Finally, major spermatozoal coding and non-coding RNAs, and proteins that are involved in the above-mentioned aspects of sperm functionality are also summarised.

Glycans in spent embryo culture medium are related to the implantation ability of blastocysts

Research questionDoes glycan profile in spent blastocyst culture medium have the potential to be used as a biomarker to predict implantation outcome. DesignA nested case-control study was conducted in Northwest women’s and children’s Hospital, Xi’an, China. The patients underwent fresh IVF/ICSI cycles with single blastocyst transfer were included. Total 78 cases were included and separated into groups according to success (n = 39) and failure (n = 39) implantation outcomes. The glycosylation patterns in spent blastocyst culture medium were detected by lectin microarray containing 37 lectins using pooled samples and confirmed by reversed lectin microarray using individual sample. ResultsBinding signals of 10 lectins were found to be different between samples from successful and failed implantation. And 8 of them were confirmed that glycans binding to lectin NPA, UEA-I, MAL-I, LCA and GNA were significantly increased while DBA and BPL were decreased in the successful implantation compared to failed implantation. The glycan binding to lectin PHA-E + L had no difference between two groups. No significant differences in the glycan profile were found in spent culture medium of embryos with different morphological grades except the glycan binding to UEA-I between blastocysts of Poor and blastocysts of Medium. ConclusionDetection of glycan profile in spent culture medium may lead to a novel non-invasive assessment assay of embryo viability. In addition, these results may be helpful to further understanding molecular mechanisms in embryo implantation.

Retrospective Analysis of Meiotic Segregation Pattern and Reproductive Outcomes in Blastocysts from Robertsonian Preimplantation Genetic Testing Cycles.

In this retrospective study, 120 heterozygous Robertsonian translocation carriers undergoing preimplantation genetic testing (PGT) were included, between January 2018 and September 2021. Meiotic segregation patterns of 462 embryos from 51 female carriers and 69 male carriers were analyzed according to chromosome type, carrier's sex, and female age. The proportion of alternate embryos in female carriers was slightly lower than that in male carriers [P < 0.001, odds ratio (OR) = 0.512]. By contrast, no difference was observed among Rob (13;14), Rob (14;21), and rare RobT groups. Stratification analysis of female carriers' age doses showed no significant increase in unbalanced chromosomal abnormalities. Reproductive outcomes of 144 frozen-thawed cycles were analyzed. All 144 blastocysts were transferred, and there were no significant differences in the clinical pregnancy rates per transfer (CPR), miscarriage rates (MR), live birth rates per transfer (LBR), and cumulative live birth rates between female carriers and male carriers. In addition, couples in Rob (13;14), Rob (14;21), and rare RobTs groups had comparative clinical pregnancy rates per transfer (CPR), miscarriage rates (MR), live birth rates per transfer (LBR), and cumulative live birth rates. Our study demonstrated that the meiotic segregation pattern of Robertsonian translocations carriers is associated with the carrier's sex, but not the carrier's translocation type and female age. In addition, the sex of translocation carriers only affects the meiotic segregation pattern but does not influence the subsequent viability of normal embryos and live birth.

Cryotop vitrification of large batches of pig embryos simultaneously provides excellent postwarming survival rates and minimal interference with gene expression

The most commonly used technique to vitrify pig embryos is the super open pulled straw (SOPS), where a maximum of 6 embryos can be vitrified simultaneously per device without compromising the minimum volume necessary for optimal preservation. Since optimal embryo transfer (ET) demands a transfer of 20–40 embryos per recipient, the customary use of SOPS complicates embryo warming and ET in field conditions. Such complications could be avoided when using the Cryotop® (OC) system, which has been proven to be an effective option for vitrifying at least 20 porcine embryos simultaneously. This study aimed to investigate the changes in the transcriptome of blastocysts caused by vitrification using both systems. In vivo-derived blastocysts were OC- (n = 60; 20 embryos/device) and SOPS- (n = 60; 4–6 embryos/device) vitrified and cultured for 24 h after warming. Nonvitrified blastocysts (n = 60) cultured for 24 h postcollection acted as controls. At the end of culture, 48 viable embryos from each group (6 pools of 8 embryos) were selected for microarray (GeneChip® Porcine Genome Array, P/N 900624, Affymetrix) analysis of differentially expressed genes (DEGs). The survival rate of embryos vitrified with the OC and SOPS systems (>97%) was similar to that of the control embryos (100%). Microarray analysis of each vitrification system compared to the control group showed 245 DEGs (89 downregulated and 156 upregulated) for the OC system and 210 (44 downregulated and 166 upregulated) for the SOPS system. Two pathways were enriched for the DEGs specifically altered in each vitrification system compared to the control (glycolysis/gluconeogenesis and carbon metabolism pathways for the OC system and amino sugar and nucleotide sugar metabolism and lysosome pathways in the SOPS group). The OC group showed 31 downregulated and 24 upregulated genes and two enriched pathways (mineral absorption and amino sugar and nucleotide sugar metabolism pathways) when compared to the SOPS group. In summary, vitrification with the OC system altered fewer genes related to apoptosis and activated genes related to cell proliferation. We conclude that vitrification with either the OC or SOPS system has a moderate to low effect on the transcriptome of in vivo-derived porcine blastocysts. Further investigation is needed to elucidate how the differences in the transcriptome of embryos vitrified with these systems affect their subsequent developmental ability after ET.

Assisting the Human Embryo Viability Assessment by Deep Learning for In Vitro Fertilization

The increasing global infertility rate is a matter of significant concern. In vitro fertilization (IVF) significantly minimizes infertility by providing an alternative clinical means of becoming pregnant. The success of IVF mainly depends on the assessment and analysis of human blastocyst components such as the blastocoel (BC), zona pellucida (ZP), inner cell mass (ICM), and trophectoderm (TE). Embryologists perform a morphological assessment of the blastocyst components for the selection of potential embryos to be used in the IVF process. Manual assessment of blastocyst components is time-consuming, subjective, and prone to errors. Therefore, artificial intelligence (AI)-based methods are highly desirable for enhancing the success rate and efficiency of IVF. In this study, a novel feature-supplementation-based blastocyst segmentation network (FSBS-Net) has been developed to deliver higher segmentation accuracy for blastocyst components with less computational overhead compared with state-of-the-art methods. FSBS-Net uses an effective feature supplementation mechanism along with ascending channel convolutional blocks to accurately detect the pixels of the blastocyst components with minimal spatial loss. The proposed method was evaluated using an open database for human blastocyst component segmentation, and it outperformed state-of-the-art methods in terms of both segmentation accuracy and computational efficiency. FSBS-Net segmented the BC, ZP, ICM, TE, and background with intersections over union (IoU) values of 89.15, 85.80, 85.55, 80.17, and 95.61%, respectively. In addition, FSBS-Net achieved a mean IoU for all categories of 87.26% with only 2.01 million trainable parameters. The experimental results demonstrate that the proposed method could be very helpful in assisting embryologists in the morphological assessment of human blastocyst components.

Real-time image and time-lapse technology to select the single blastocyst to transfer in assisted reproductive cycles

The success of an assisted reproduction cycle should be the achievement of a healthy singleton live birth following the replacement of one embryo. Therefore, one of the most critical points for embryologists has been the selection criteria and how to choose the best embryo to transfer with high implantation potential. In this vein, morphological evaluation has been historically the method applied. However, this practice relies on a limited number of single observations and is associated with high operator variability. Recently, a major innovation in embryo culture has been the introduction of a new type of incubator with integrated time-lapse monitoring, which enables the embryologist to analyze the dynamic events of embryo development, from fertilization to blastocyst formation. This novel practice is quickly growing and has been implemented in many IVF clinics worldwide. Therefore, the main aim of this review is to illustrate the benefits of time-lapse technology in a modern embryology laboratory. In particular, we discuss the blastocyst collapse(s) event and morphometric blastocyst assessment and analyse their association with embryo viability and implantation potential.