Culture time to optimize embryo cell-free DNA (cfDNA) analysis for frozen-thawed blastocysts undergoing non-invasive preimplantation genetic testing for aneuploidy (niPGT-A).

OBJECTIVE: Cell-free DNA (cfDNA) is released into the spent blastocyst media (spent media) by the embryo. However, optimal timing to determine maximal cfDNA in the case of frozen-thawed blastocysts undergoing non-invasive preimplantation genetic testing for aneuploidy (niPGT-A) remains to be elucidated. In the current study we investigated the ideal time in culture to optimize embryo cell-free DNA (cfDNA) analysis in frozen-thawed blastocysts undergoing niPGT-A. DESIGN: In this prospective observational study, 135 spent media and corresponding whole blastocysts were collected from January 2021 through March 2022. SUBJECTS: Day-5 frozen-thawed blastocysts were cultured for 8 hours (Day-5 Short) or 24 hours (Day-5 Long), while day-6 frozen-thawed blastocysts were cultured for 8 hours (Day-6 Short). The spent media and whole blastocysts were then collected for further analysis. Spent media and whole blastocysts were amplified using whole genome amplification (WGA) and sequenced using Next Generation Sequencing (NGS). MAIN OUTCOME MEASURES: Informativity and concordance rates between cfDNA in spent media and whole blastocysts DNA were compared according to the different time in culture. RESULTS: When comparing time in culture, informativity rates for spent media were significantly higher (p<0.0001) for Day-5 Long and Day-6 Short (>91%) compared to the Day-5 Short group (<60%). A similar trend was observed for cases with and without a previous PGT-A. Regarding blastocyst expansion grade, informativity rates were lower in Day-5 Short, compared to Day-5 Long and Day-6 Short, regardless of expansion degree. This decrease was significant for Gardner grade expansion grade 3 (p=0.0005), 4 (p=0.0366) and 5-6 (p=0.0002). In addition, for a similar time in culture, the grade of expansion did not have an impact on the informativity rates. For concordance rates, no significant differences were observed among the three groups. In all cases concordance rates were 90.5% for Day-5 Short, 93.6% for Day-5 Long and 92.3% for Day-6 Short. No impact of the expansion grade was observed on concordance rates. CONCLUSION: niPGT-A in frozen-thawed blastocysts yields very high concordance rates with whole blastocysts, possibly limiting the need for invasive PGT-A and making it available for a wider range of patients.

Human embryo live imaging reveals nuclear DNA shedding during blastocyst expansion and biopsy.

Proper preimplantation development is essential to assemble a blastocyst capable of implantation. Live imaging has uncovered major events driving early development in mouse embryos; yet, studies in humans have been limited by restrictions on genetic manipulation and lack of imaging approaches. We have overcome this barrier by combining fluorescent dyes with live imaging to reveal the dynamics of chromosome segregation, compaction, polarization, blastocyst formation, and hatching in the human embryo. We also show that blastocyst expansion mechanically constrains trophectoderm cells, causing nuclear budding and DNA shedding into the cytoplasm. Furthermore, cells with lower perinuclear keratin levels are more prone to undergo DNA loss. Moreover, applying trophectoderm biopsy, a mechanical procedure performed clinically for genetic testing, increases DNA shedding. Thus, our work reveals distinct processes underlying human development compared with mouse and suggests that aneuploidies in human embryos may not only originate from chromosome segregation errors during mitosis but also from nuclear DNA shedding.

Optimized NGS Approach for Detection of Aneuploidies and Mosaicism in PGT-A and Imbalances in PGT-SR.

The detection of chromosomal aneuploidies and mosaicism degree in preimplantation embryos may be essential for achieving pregnancy. The aim of this study was to determine the robustness of diagnosing homogenous and mosaic aneuploidies using a validated algorithm and the minimal resolution for de novo and inherited deletions and duplications (Del/Dup). Two workflows were developed and validated: (a,b) preimplantation genetic testing for uniform whole and segmental aneuploidies, plus mixtures of euploid/aneuploid genomic DNA to develop an algorithm for detecting mosaicism; and (c) preimplantation genetic testing for structural rearrangements for detecting Del/Dup ≥ 6 Mb. Next-generation sequencing (NGS) was performed with automatic library preparation and multiplexing up to 24-96 samples. Specificity and sensitivity for PGT-A were both 100% for whole chromosomes and segmentals. The thresholds stablished for mosaicism were: euploid embryos (<30% aneuploidy), low mosaic (from 30% to <50%), high mosaic (50-70%) or aneuploid (>70%). In the PGT-SR protocol, changes were made to increase the detection level to ≥6 Mb. This is the first study reporting an accurate assessment of semiautomated-NGS protocols using Reproseq on pools of cells. Both protocols allow for the analysis of homogeneous and segmental aneuploidies, different degrees of mosaicism, and small Del/Dup with high sensitivity and specificity.

Multicenter prospective study of concordance between embryonic cell-free DNA and trophectoderm biopsies from 1301 human blastocysts.

BACKGROUND: The recent identification of embryonic cell-free DNA in spent blastocyst media has opened a new era of possibilities for noninvasive embryo aneuploidy testing in assisted reproductive technologies. Yet, previous studies assessing a limited number of embryos reported variable concordance between embryonic cell-free DNA and trophectoderm biopsies, thus questioning the validity of this approach. OBJECTIVE: This study aimed to evaluate the concordance and reproducibility of testing embryonic cell-free DNA vs trophectoderm DNA obtained from the same embryo in a large sample of human blastocysts and to assess the contribution of the inner cell mass and trophectoderm to embryonic cell-free DNA released to the culture media. STUDY DESIGN: This is an interim analysis of a prospective, observational study among 8 in vitro fertilization centers in 4 continents to assess consistency between noninvasive embryo aneuploidy testing of embryonic cell-free DNA and conventional trophectoderm biopsy. The analysis included 1301 day-6/7 blastocysts obtained in 406 in vitro fertilization cycles from 371 patients aged 20-44 years undergoing preimplantation genetic testing for aneuploidy. Fresh oocytes underwent intracytoplasmic sperm injection or in vitro fertilization. No previous assisted hatching or vitrification was allowed before media collection. Individual spent blastocyst medium was collected from embryos cultured at least 40 hours from day 4. After media collection, conventional preimplantation genetic testing for aneuploidy, comprising trophectoderm biopsy and blastocyst vitrification, was performed. Embryonic cell-free DNA was analyzed blindly after embryo transfer. Inner cell mass and trophectoderm biopsies were also performed in a subset of 81 aneuploid blastocysts donated for research. RESULTS: Embryonic cell-free DNA analyses were 78.2% (866/1108) concordant with the corresponding trophectoderm biopsies. No significant differences were detected among centers ranging from 72.5% to 86.3%. Concordance rates exceeded 86% when all defined steps in the culture laboratory were controlled to minimize the impact of maternal and operator contamination. Sensitivity per center ranged from 76.5% to 91.3% and specificity from 64.7% to 93.3%. The false-negative rate was 8.3% (92/1108), and false-positive rate was 12.4% (137/1108). The 2 fertilization techniques provided similar sensitivity (80.9% vs 87.9%) and specificity (78.6% vs 69.9%). Multivariate analysis did not reveal any bias from patient clinical background, ovarian stimulation protocols, culture conditions, or embryo quality on testing accuracy of concordance. Moreover, concordances of embryonic cell-free DNA with trophectoderm and inner cell mass suggest that the embryonic cell-free DNA originates from both compartments of the human embryo. CONCLUSION: Noninvasive analysis of embryonic cell-free DNA in spent blastocyst culture media demonstrates high concordance with trophectoderm biopsy results in this large multicenter series. A noninvasive approach for prioritizing embryo euploidy offers important advantages such as avoiding invasive embryo biopsy and decreased cost, potentially increasing accessibility for a wider patient population.

Dopamine agonist inhibits vascular endothelial growth factor protein production and secretion in granulosa cells.

BACKGROUND: Dopamine receptor 2 agonists (D2-ags) inhibit vascular endothelial growth factor (VEGF) secretion in luteinized granulosa cells (LGCs) both in vitro and in vivo. However, the mechanism of D2 regulation of the VEGF/VEGF Receptor 2 (VEGFR-2) pathway remains to be elucidated. We sought to determine the effects of D2 signaling on VEGF transcription and translation in LGCs, with the expectation of identifying potential D2-ag-based therapies for ovarian hyperstimulation syndrome (OHSS). FINDINGS: LGCs from egg donors were cultured with chorionic gonadotropin (hCG) in the presence of Actinomycin-D (ActD) or Brefeldin-A (BFA) to evaluate the effects of a D2-ag, cabergoline (Cb2), on VEGF secretion. The contribution of the conventional Gi/Go, Gz and AKT/ß-Arrestin pathways in the VEGF regulation was assessed by adding pertussis toxin (PTX), phorbol 12-myristate 13-acetate (PMA), or wortmannin (WT). While Cb2 inhibited VEGF secretion by interfering with VEGF peptide translation and secretion, inhibition of conventional D2 transduction pathways did not reverse Cb2-mediated inhibition of VEGF secretion. CONCLUSIONS: The effects of D2-ag on VEGF translation and secretion are mediated by D2 signaling pathways that have yet to be described. We found that D2-ag inhibits VEGF secretion at the post-transcriptional level, suggesting that D2-ag treatment should be combined with therapies that inhibit VEGF transcription, such as the employment of LH or GnRH for triggering ovulation, to improve the efficacy of OHSS prevention.

Dopamine receptor 2 activation inhibits ovarian vascular endothelial growth factor secretion in an ovarian hyperstimulation syndrome (OHSS) animal model: implications for treatment of OHSS with dopamine receptor 2 agonists.

OBJECTIVE: To explore whether a dopamine receptor 2 agonist (D2-ag) can prevent ovarian hyperstimulation syndrome (OHSS) in a rat model by decreasing ovarian vascular endothelial growth factor (VEGF) production. DESIGN: Experimental study in an OHSS animal model. SETTING: University-affiliated infertility center. PATIENT(S): Immature Wistar rats. INTERVENTION(S): Immature rats were stimulated with gonadotropins to mimic OHSS and treated with a D2-ag and/or D2-antagonists (D2-ant). Vascular permeability (VP) was measured at the endpoint, and ovaries were collected to assess the effects of these drugs on VEGF production. MAIN OUTCOME MEASURE(S): VP was estimated by measuring the peritoneal extravasation of a previously injected dye. Ovarian VEGF mRNA expression and VEGF protein levels were assessed by quantitative real-time PCR and Western blots, respectively. RESULT(S): The D2-ag exerted a reduction in VP that was associated with a drastic decrease in VEGF protein production in OHSS rat ovaries. The effects of this D2-ag on VP and VEGF protein levels were partially reversed by concomitant administration of a D2-ant. Ovarian VEGF mRNA expression levels were unaffected by these drugs in OHSS rats. CONCLUSION(S): D2-ags prevent increased VP in OHSS rats by decreasing ovarian VEGF production, very likely through a D2-mediated post-transcriptional mechanism. Given the dose-dependent inhibitory effect of D2-ags on ovarian VEGF production reported herein, we infer that current OHSS therapies used in humans may be improved by increasing the intraovarian concentration of D2-ags in these patients.

Dopamine receptor 2 activation inhibits ovarian vascular endothelial growth factor secretion in vitro: implications for treatment of ovarian hyperstimulation syndrome with dopamine receptor 2 agonists.

OBJECTIVE: To ascertain whether vascular endothelial growth factor (VEGF) secretion by luteinized granulosa cells (GCs) is modulated by the dopaminergic system in a dose-dependent fashion and how this is related to the differential efficacy of dopamine receptor 2 (D2)-agonists (D2-ag) in preventing ovarian hyperstimulation syndrome (OHSS). DESIGN: The relationship between the dopaminergic system and VEGF secretion in luteinized GCs was evaluated. Archived human ovaries were immunostained to characterize D2 expression. SETTING: University affiliated infertility center. PATIENT(S): Premenopausal women and egg donors. INTERVENTION(S): Luteinized GCs were cultured with the D2-ag cabergoline. Human ovarian sections were immunostained for D2. MAIN OUTCOME MEASURE(S): The VEGF was measured by ELISA and D2 expression was evaluated by In-Cell ELISA. The D2 expression throughout the luteal phase was characterized by immunohistochemistry. RESULT(S): The VEGF secretion was decreased by the D2-ag in a dose-dependent fashion. The efficiency of this process was correlated with the amount of D2 expressed by luteinized GCs. A decrease in D2 expression in ovarian sections was observed during the late luteal phase. CONCLUSION(S): The efficacy of D2-ags in preventing OHSS might rely on their capacity to inhibit VEGF secretion by luteinized GCs. Because this capacity is dose-dependent, increasing the intraovarian concentration of D2-ags should be explored as a means of increasing the efficacy of these drugs in preventing OHSS.

Delta-like ligand 4 regulates vascular endothelial growth factor receptor 2-driven luteal angiogenesis through induction of a tip/stalk phenotype in proliferating endothelial cells.

OBJECTIVE: To explore whether the Dll4/Notch-1 signaling pathway modulates vascular endothelial growth factor (VEGF)-dependent luteal angiogenesis and related function, by inducing a tip/stalk phenotype in endothelial cells (ECs). DESIGN: Experimental laboratory animal study. SETTING: University-affiliated infertility center. ANIMAL(S): Immature female mice. INTERVENTION(S): The presence of leading tip ECs in growing luteal vessel was identified by immunofluorescent analysis of Dll4 in the ovaries of hormonally stimulated female mice. The effects of Dll4 inhibition on luteal vessels functionality and related corpus luteum function were assessed by administering a Dll4 blocking antibody or placebo to hormonally stimulated female mice. MAIN OUTCOME MEASURE(S): Alteration of the tip/stalk phenotype was identified by immunofluorescence analysis of luteal vascular density, Dll4, Notch-1, and VEGF receptor 2 expression. Lectin perfusion was used to assay blood vessel functionality, whereas apoptosis and P levels were quantified to determine the effects on luteal function. RESULT(S): Expression of Dll4 was restricted to the tip of growing vessels. Inhibition of Dll4 signaling promotes promiscuous Dll4 expression, leading to increased, but paradoxically, nonfunctional vascularization, which was associated with decreased P levels. CONCLUSION(S): The Dll4/Notch-1 signaling pathway has a modulatory role in VEGF-dependent luteal angiogenesis and related function through induction of a tip/stalk phenotype.

Efficiency and purity provided by the existing methods for the isolation of luteinized granulosa cells: a comparative study.

BACKGROUND: Several protocols for the isolation of luteinized granulosa cells (LGCs) contained in follicular fluid have been described but no previously published study has compared the relative efficiency of these protocols. Our objective is to obtain conclusive scientific evidence for the superiority of one method over another. METHODS: Different purification methods for LGCs based on the recognition of specific cell markers, aggregates, differential adhesion and LGC size were evaluated. We compared the levels of CD45 cell contamination and the percentage of total cell viability in paired aliquots of cells (before and after purification) derived from the follicular fluid obtained from women who were donating oocytes (n = 72). Each of the six purification methods was performed six times using pooled follicular fluids from two women. RESULTS: Samples processed by means of recognition of specific cell markers were characterized by their greater purity (0.1-1.33% CD45+) but low rate of LGC recovery (17.13-25.4%) when compared with the other methods (3.29-12% CD45+, P < 0.05 and 51.67-73.20% LGC, P < 0.05). It is noteworthy that the filter method, which is based on the LGC size, combined one of the highest rates of LGC recovery (∼70%) with acceptable low levels of contamination (<5%). CONCLUSIONS: There is currently no gold standard method for the isolation of LGCs, and protocols should be chosen depending on the purpose in question. We conclude that fluorescence-activated cell sorting is the best protocol for isolating LGCs when purity is the principal criterion, and magnetic separation when both purity and viability are essential. However, cell straining (filter) is probably the least laborious and, overall, the most efficient method to isolate LGCs.