The impact of microfluidics sperm processing on blastocyst euploidy rates compared with density gradient centrifugation: a sibling oocyte double-blinded prospective randomized clinical trial

OBJECTIVE

To compare the euploidy rates among blastocysts created from sibling oocytes injected with sperm and processed using microfluidics or density gradient centrifugation.

DESIGN

Sibling oocyte randomized controlled trial.

SETTING

Single university-affiliated infertility practice.

PATIENTS

A total of 106 patients aged 18-42 years undergoing fresh in vitro fertilization treatment cycles with preimplantation genetic testing between January 2021 and April 2022 contributed 1,442 mature oocytes, which were injected with sperm and processed using microfluidics or density gradient centrifugation.

INTERVENTION(S)

The sperm sample is divided and processed using a microfluidics device and density gradient centrifugation for injection into sibling oocytes.

MAIN OUTCOME MEASURE(S)

The primary outcome was the embryo euploidy rate. Secondary outcomes included fertilization, high-quality blastulation, and ongoing pregnancy rates.

RESULT(S)

The blastocyst euploidy rate per mature oocyte was not significantly different in the study group compared with the control group (22.9% vs. 20.5%). The blastocyst euploidy rate per biopsied embryo was also similar between the 2 groups (53.0% vs. 45.7%). However, the fertilization rate per mature oocyte injected was found to be significantly higher in the study group compared with the control group (76.0% vs. 69.9%). The high-quality blastulation rate per mature oocyte injected was similar between the 2 groups, as was the total number of embryos frozen. There were no differences in the number of participants with no blastocysts for biopsy or the number of participants with no euploid embryos between the 2 groups. Among the male factor infertility and recurrent pregnancy loss subgroups, there were no differences in euploidy rates, fertilization rates, blastulation rates, or total numbers of blastocysts frozen, although the study was underpowered to detect these differences. Seventy-seven patients underwent frozen embryo transfer; there were no significant differences in pregnancy outcomes between the 2 groups.

CONCLUSION(S)

Microfluidics processing did not improve embryo euploidy rates compared with density gradient centrifugation in this sibling oocyte study, although fertilization rates were significantly higher.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04744025.

Attitudes towards disposition of cryopreserved sperm in the event of death

INTRODUCTION

To evaluate patient preference for sperm disposition in case of death based on demographic factors and infertility etiology.

MATERIALS AND METHODS

This retrospective cohort study was performed at a university hospital-affiliated fertility center. Charts of 550 men undergoing cryopreservation for assisted reproductive technologies (ART) between 2016-2019 were reviewed to create a descriptive dataset. Patients previously signed consent forms stating their preference for sperm transfer to their partner or disposal in the event of their subsequent death. Patients undergoing sperm cryopreservation for the purpose of ART were analyzed to assess associations between demographic characteristics and etiology of infertility and their choice to either transfer sperm to their partner or discard.

RESULTS

A total of 84.9% (342/403) of patients included in final analyses elected to transfer their sperm to their partner in the event of their death. Factors associated with a significantly increased likelihood to transfer versus discard included a male-factor infertility diagnosis compared to female-factor infertility diagnosis (transfer rate 89.3% vs. 79.9%; p = .022) and commercial insurance coverage versus non-commercial/no insurance coverage (transfer rate 86.3% vs. 75.0%, p = .029). No significant differences relating to age, race/ethnicity, occupation classification, marital status or duration of marriage, or prior paternity were found.

CONCLUSION

A majority of male patients seeking sperm cryopreservation for ART elected to transfer their sperm to their partner if future death should occur. There does not appear to be a clear factor that would impact this decision based on demographic characteristics.

Rationale and study design of a double-blinded prospective randomized clinical trial comparing euploidy rates among embryos created from sibling oocytes injected with sperm processed by microfluidics or by density gradient centrifugation

BACKGROUND

During the in vitro fertilization (IVF) process, sperm must be processed prior to insemination. While the most common method, density gradient centrifugation, can potentially damage sperm during centrifugation, a recent advancement in sperm processing uses a microfluidics system which selects for the most highly motile sperm. In selecting for these sperm which may be of higher quality, the euploidy rates of embryos created as a result may also be improved. The primary aim of this study is to compare the euploidy rates per mature oocyte between embryos created from sibling oocytes injected with sperm processed by microfluidics sorting or by density gradient centrifugation.

METHODS

This is a double-blinded prospective randomized sibling oocyte study including patients undergoing treatment with IVF with intracytoplasmic sperm injection (ICSI) and preimplantation genetic testing (PGT). After controlled ovarian hyperstimulation, oocytes from each patient will be separated into two groups. Each group will be randomized to sperm processed using either microfluidics or density gradient centrifugation and embryos biopsied for PGT to assess euploidy rates. A sample size of 686 oocytes in each group for a total of 1372 oocytes will provide 80% power to detect a significant difference in the euploidy rates per mature oocyte between the two groups. An ancillary study examining the relationship between sperm processing method and sperm DNA fragmentation will be assessed.

CONCLUSION

This study will offer insight into the sperm's contribution to embryo euploidy, and has the potential to provide an alternative method of improving euploidy rates in clinical practice.

Independent serum markers of corpora lutea function after gonadotropin-releasing hormone agonist trigger and adjuvant low dose human chorionic gonadotropin in in vitro fertilization

OBJECTIVE

To characterize corpora lutea (CL) function after gonadotropin-releasing hormone agonist (GnRHa) trigger with the use of adjuvant human chorionic gonadotropin (hCG).

DESIGN

Secondary analysis of serum from prospective randomized clinical trial.

SETTING

University-based fertility center.

PATIENT(S)

Women under 40 years of age at risk of ovarian hyperstimulation syndrome (OHSS) with serum E₂ level <4,000 pg/mL.

INTERVENTIONS(S)

All subjects underwent ovarian stimulation with the use of a GnRH antagonist protocol. Within a larger study, subjects were randomized to receive 1,000 IU hCG at the time of GnRHa trigger and placebo at the time of vaginal oocyte retrieval (VOR) or placebo at the time of GnRHa trigger and 1,500 IU hCG at the time of VOR.

MAIN OUTCOME MEASURE(S)

Luteal phase and early pregnancy curves of serum prorenin and 17α-hydroxyprogesterone (17OH-P).

RESULT(S)

Thirty subjects enrolled in this secondary analysis. Serum 17OH-P peaked in the early luteal phase, 5 days after GnRHa trigger, with a nadir in the mid-luteal phase 9 days after trigger. Serum prorenin peaked in the luteal phase 2 days after GnRHa trigger, independently from adjuvant hCG timing, and reached a nadir at 9 days after trigger. CL function appears higher when adjuvant hCG is given at VOR compared with adjuvant hCG given at the time of trigger.

CONCLUSION(S)

CL function, as interpreted by proxy measures of serum prorenin and 17OH-P with pregnancy, continues despite GnRHa trigger. Both options for adjuvant hCG timing are sufficient for CL rescue and successful pregnancy, so the potential for OHSS risk with increased CL activity after hCG at VOR should be considered.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01815138.

The National Physicians Cooperative: transforming fertility management in the cancer setting and beyond

Once unimaginable, fertility management is now a nationally established part of cancer care in institutions, from academic centers to community hospitals to private practices. Over the last two decades, advances in medicine and reproductive science have made it possible for men, women and children to be connected with an oncofertility specialist or offered fertility preservation soon after a cancer diagnosis. The Oncofertility Consortium's National Physicians Cooperative is a large-scale effort to engage physicians across disciplines – oncology, urology, obstetrics and gynecology, reproductive endocrinology, and behavioral health – in clinical and research activities to enable significant progress in providing fertility preservation options to children and adults. Here, we review the structure and function of the National Physicians Cooperative and identify next steps.

Multidomain Skyrmion Lattice State in Cu2OSeO3

Magnetic skyrmions in chiral magnets are nanoscale, topologically protected magnetization swirls that are promising candidates for spintronics memory carriers. Therefore, observing and manipulating the skyrmion state on the surface level of the materials are of great importance for future applications. Here, we report a controlled way of creating a multidomain skyrmion state near the surface of a Cu2OSeO3 single crystal, observed by soft resonant elastic X-ray scattering. This technique is an ideal tool to probe the magnetic order at the L3 edge of 3d metal compounds giving an average depth sensitivity of ∼50 nm. The single-domain 6-fold-symmetric skyrmion lattice can be broken up into domains, overcoming the propagation directions imposed by the cubic anisotropy by applying the magnetic field in directions deviating from the major cubic axes. Our findings open the door to a new way to manipulate and engineer the skyrmion state locally on the surface or on the level of individual skyrmions, which will enable applications in the future.

Néel-type skyrmion lattice with confined orientation in the polar magnetic semiconductor GaV4S8

Following the early prediction of the skyrmion lattice (SkL)--a periodic array of spin vortices--it has been observed recently in various magnetic crystals mostly with chiral structure. Although non-chiral but polar crystals with Cnv symmetry were identified as ideal SkL hosts in pioneering theoretical studies, this archetype of SkL has remained experimentally unexplored. Here, we report the discovery of a SkL in the polar magnetic semiconductor GaV4S8 with rhombohedral (C3v) symmetry and easy axis anisotropy. The SkL exists over an unusually broad temperature range compared with other bulk crystals and the orientation of the vortices is not controlled by the external magnetic field, but instead confined to the magnetic easy axis. Supporting theory attributes these unique features to a new Néel-type of SkL describable as a superposition of spin cycloids in contrast to the Bloch-type SkL in chiral magnets described in terms of spin helices.

Sequential embryo assessment outperforms investigator-driven morphological assessment at selecting a good quality blastocyst

Two selection methods (morphology-only and a sequential embryo assessment algorithm) were compared within the same IVF clinic to determine which method best identifies the embryos on day 3 that will develop into the highest quality on day 5. The sequential embryo assessment algorithm was significantly better at selecting the best embryo and selecting a blastocyst compared with the morphology-only method.

A soluble molecule secreted by human blastocysts modulates regulation of HOXA10 expression in an epithelial endometrial cell line

OBJECTIVE

To determine the existence of a soluble signal, secreted from the human blastocyst embryo, that induces HOXA10 gene expression before cell-cell contact.

DESIGN

To analyze, by semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), cell-free media that had contained human embryos cultured to the blastocyst stage for a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa).

SETTING

Assisted reproduction technology program of Yale University, New Haven, Connecticut.

PATIENT(S)

Patients undergoing intracytoplasmic sperm injection (ICSI) or in vitro fertilization (IVF) cycles. Treatment of Ishikawa cells with blastocyst-conditioned media.

MAIN OUTCOME MEASURE(S)

Determination of HOXA10 gene expression.

RESULT(S)

We demonstrate that cell-free media that had contained human embryos cultured to the blastocyst stage contain a soluble molecule that induces HOXA10 expression in an endometrial epithelial cell line (Ishikawa). We found that hCG does not induce HOXA10 in Ishikawa cells.

CONCLUSION(S)

Soluble molecules induce a well-characterized marker of endometrial receptivity in endometrial cells without blastocyst apposition. Additionally, HOXA10 induction can serve as a means of evaluating human embryos cultured for IVF and ET. High quality embryos may induce local endometrial receptivity before trophectoderm-endometrial contact.

Sequential assessment of individually cultured human embryos as an indicator of subsequent good quality blastocyst development

BACKGROUND

It is of fundamental importance for IVF clinics to determine the most viable embryos for transfer. The challenge for ART clinics is to transfer fewer embryos, thereby minimizing the risk of multiple-infant births, while still maintaining the greatest chance of pregnancy for their patients. In this study, an investigation was made to determine if developmental markers on the day of fertilization (day 1) can predict good subsequent blastocyst development.

METHODS AND RESULTS

A total of 1550 individually cultured 2PN embryos from 191 patients undergoing IVF/ICSI treatment at the Yale University Center for Reproductive Medicine and Infertility from February to December 2001 was included. The results showed a significant positive relationship between early-cleaving 2-cell embryos and subsequent good quality > or =4-cell, > or =7-cell and blastocyst development (P < 0.05). PN symmetry (the relative size of the PN to each other), when checked at the time fertilization, is also a significant indictor of good quality > or =4-cell, > or =7-cell stage embryos and blastocysts. Combined, a developing embryo showing PN symmetry with early cleavage and subsequent good > or =4-cell and > or =7-cell cleavage, has a one in two chance of developing into a good-quality blastocyst.

CONCLUSION

Early embryo assessment can be used as an indicator of subsequent good blastocyst development.

Analysis of DNA fragmentation of in vitro cultured bovine blastocysts using TUNEL

Programmed cell death (apoptosis) characteristically affects the single cells of blastocysts whereas necrosis affects cluster of cells in both the inner cell mass (ICM) and the trophectoderm (TE). This study uses the trophectodermrminal deoxynucleotidyl transferase (TdT) mediated dUTP nick-end labeling (TUNEL) assay as a way of evaluating the proportion of apoptotic cells and, thus, bovine blastocyst quality during in vitro culture at Days 6,7, and 8. Furthermore, parthenogenetic blastocysts were compared to in vitro fertilized blastocysts at Day 7. Confocal microscopy was used to generate three-dimensional reconstructions of the blastocysts. Apoptosis was observed in both early (Day 6) and late (Day 8) developing blastocysts. The dead cell index (DCI, total number of apoptotic nuclei/total number of nuclei) tend to increase as the in vitro culture time increases, and apoptosis is proportionately higher in the ICM than in the TE. The ratio of ICM to TE cells remains relatively constant even as the blastocysts cell number increases (Day 6 = 11.9 +/- 2.2, Day 7 = 11.2 +/- 0.5, Day 8 = 11.7 +/- 0.4). The overall cell number is significantly reduced in parthenogenetic blastocysts compared to Day 7 in vitro produced blastocysts (P = 0.037). The parthenogenetic blastocysts also show an increase of apoptosis over Day 7 controls. The decrease in cell number in the parthenogenetic blastocysts may be due to the increase of apoptotic nuclei observed. Based on these results we found the TUNEL assay to be a useful method for evaluating in vitro culture conditions of pre-implantation bovine embryos.

Accumulation of the proteolytic marker peptide ubiquitin in the trophoblast of mammalian blastocysts

Ubiquitination is a universal protein degradation pathway in which the molecules of 8.5-kDa proteolytic peptide ubiquitin are covalently attached to the epsilon-amino group of the substrate's lysine residues. Little is known about the importance of this highly conserved mechanism for protein recycling in mammalian gametogenesis and fertilization. The data obtained by the students and faculty of the international training course Window to the Zygote 2000 demonstrate the accumulation of ubiquitin-cross-reactive structures in the trophoblast, but not in the inner cell mass of the expanding bovine and mouse blastocysts. This observation suggests that a major burst of ubiquitin-dependent proteolysis occurs in the trophoblast of mammalian peri-implantation embryos. This event may be important for the success of blastocyst hatching, differentiation of embryonic stem cells into soma and germ line, and/or implantation in both naturally conceived and reconstructed mammalian embryos.

Ubiquitin-dependent sperm quality control mechanism recognizes spermatozoa with DNA defects as revealed by dual ubiquitin-TUNEL assay

Defective mammalian spermatozoa become ubiquitinated during epididymal passage, a mechanism that may mark the abnormal spermatozoa for proteolytic destruction (Sutovsky et al., 2001a: J Cell Sci 114:1665-1675). It is not known how such spermatozoa are recognized by the epididymal ubiquitination pathway and whether there is a selection against certain types of sperm defects. We examined the relationship between sperm ubiqutination, lifelong sperm morphology and sperm DNA defects using a single chanel, ubiquitin-activated flow cytometric assay, and a dual, ubiquitin-TUNEL assay. Semen samples from nine service sires of good-to-average fertility were screened. A positive correlation was found between sperm ubiquitination and the average frequency of morphological semen abnormalities from field evaluations performed throughout the reproductive life of individual sires. Sample correlation coefficients were r=0.65 for primary (head and tail) and r=0.60 for total semen abnormalities in the single channel assay. In a dual assay, we found a high, positive correlation (r=0.93) between the ubiquitin-positive sperm and the TUNEL positive sperm. Substantial correlations (r=0.47-0.64) were observed when the measurements from these two respective assays were compared for individual sires. While anti-ubiquitin antibodies recognized most of the TUNEL-positive sperm cells, the TUNEL-positive spermatozoa represented only a subset (approximately 20-40%) of all ubiquitin-positive cells. It appears that the ubiquitin-dependent sperm quality control, residing in the epididymal epithelium, has the ability to detect spermatozoa with apoptotic or necrotic DNA, while spermatozoa with defects other than DNA fragmentation are also recognized and ubiquitinated.

Clonal propagation of primate offspring by embryo splitting

Primates that are identical in both nuclear and cytoplasmic components have not been produced by current cloning strategies, yet such identicals represent the ideal model for investigations of human diseases. Here, genetically identical nonhuman embryos were produced as twin and larger sets by separation and reaggregation of blastomeres of cleavage-stage embryos. A total of 368 multiples were created by the splitting of 107 rhesus embryos with four pregnancies established after 13 embryo transfers (31% versus 53% in vitro fertilization controls). The birth of Tetra, a healthy female cloned from a quarter of an embryo, proves that this approach can result in live offspring.

Is the mouse a clinically relevant model for human fertilization failures?

This study compares failed fertilization oocytes from patients participating in an in-vitro fertilization (IVF) programme with failed fertilization oocytes from B6SJLF(1)/J mice, in order to characterize and describe the distribution of DNA in oocytes that do not undergo normal fertilization. Our goal is to evaluate the mouse IVF system as a model to gain insight into reasons for human fertilization failures. All oocytes were stained with the vital fluorescent dye, Hoechst 33342, which rapidly stains double-stranded DNA. Of the 237 human oocytes that had been scored as failed fertilization by brightfield microscopy, 61 (25.7%) showed the presence of at least one spermatozoon within the oocyte cytoplasm. In contrast, out of 69 failed fertilization mouse oocytes, only one oocyte showed the presence of a spermatozoon within its cytoplasm. Mouse failed fertilization oocytes exhibited a significantly lower internal sperm rate (P < 0.0001) than human failed fertilization oocytes. Human failed fertilization oocytes show a higher incidence of sperm penetration, but the cytoplasm fails to support pronuclear development, whereas, at least in this strain, mouse failed fertilization oocytes arise from an inability of the spermatozoa to penetrate the oocyte. This study suggests that the mouse is not a clinically relevant model for human fertilization failures.

Efficient human sperm pronucleus formation and replication in Xenopus egg extracts

We have achieved efficient in vitro reactivation and replication of human sperm nuclei in frog egg extracts by constructing a 4-step protocol that mimics the events of fertilization and pronucleus formation in mammalian eggs. With use of this protocol, 78-97% of human sperm nuclei from fertile donors synchronously swelled and completed full genome replication in about 2 h. We document the changes in nuclear structure that accompany efficient DNA synthesis and discuss future research and potential clinical implications of this new system.

Effects of fluorine substitution on the DNA binding and tumorigenicity of benzo[b]fluoranthene in mouse epidermis

The effects of fluorine substitution on benzo[b]fluoranthene (B[b]F) DNA adduct formation and tumorigenicity in mouse epidermis were investigated. Fluoro derivatives studied included 1-, 6-, 7-, 8-, 9- and 11-fluoroB[b]F as well as 1,9- and 6,9-difluoroB[b]F. Each compound was applied topically to mice and hydrocarbon/DNA adduct formation was assessed using the 32P-post-labelling technique. All of the fluorinated compounds bound to DNA to a lesser extent than B[b]F. Among the fluorinated compounds, the greatest binding was observed for 8-fluoroB[b]F. Lowest levels of hydrocarbon/DNA adduct formation from the fluoro derivatives were observed for 1-, 7-, 11- and 6,9-difluoroB[b]F. The tumor-initiating activities on mouse skin of 7-, 9- and 11-fluoroB[b]F were determined. All three compounds were significantly less tumorigenic than B[b]F. The results of this study are discussed with respect to possible mechanisms of metabolic activation of B[b]F.