Rescue in vitro maturation using ovarian support cells of human oocytes from conventional stimulation cycles yields oocytes with improved nuclear maturation and transcriptomic resemblance to in vivo matured oocytes.

PURPOSE: Determine if the gene expression profiles of ovarian support cells (OSCs) and cumulus-free oocytes are bidirectionally influenced by co-culture during in vitro maturation (IVM). METHODS: Fertility patients aged 25 to 45 years old undergoing conventional ovarian stimulation donated denuded immature oocytes for research. Oocytes were randomly allocated to either OSC-IVM culture (intervention) or Media-IVM culture (control) for 24-28 h. The OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture with human chorionic gonadotropin (hCG), recombinant follicle stimulating hormone (rFSH), androstenedione, and doxycycline supplementation. The Media-IVM control lacked OSCs and contained the same supplementation. A limited set of in vivo matured MII oocytes were donated for comparative evaluation. Endpoints consisted of MII formation rate, morphological and spindle quality assessment, and gene expression analysis compared to in vitro and in vivo controls. RESULTS: OSC-IVM resulted in a statistically significant improvement in MII formation rate compared to the Media-IVM control, with no apparent effect on morphology or spindle assembly. OSC-IVM MII oocytes displayed a closer transcriptomic maturity signature to IVF-MII controls than Media-IVM control MII oocytes. The gene expression profile of OSCs was modulated in the presence of oocytes, displaying culture- and time-dependent differential gene expression during IVM. CONCLUSION: The OSC-IVM platform is a novel tool for rescue maturation of human oocytes, yielding oocytes with improved nuclear maturation and a closer transcriptomic resemblance to in vivo matured oocytes, indicating a potential enhancement in oocyte cytoplasmic maturation. These improvements on oocyte quality after OSC-IVM are possibly occurring through bidirectional crosstalk of cumulus-free oocytes and ovarian support cells.

hMG addition affects the change in progesterone level during IVF stimulation and LBR: a retrospective cohort study.

BACKGROUND: Premature progesterone (P) rise during IVF stimulation reduces endometrial receptivity and is associated with lower pregnancy rates following embryo transfer (ET), which can influence provider recommendation for fresh or frozen ET. This study aimed to determine whether change in P level between in IVF baseline and trigger (𝚫P) is predictive of pregnancy outcome following fresh ET, and whether the ratio of gonadotropins influences P rise and, as a result, clinical pregnancy outcomes: clinical pregnancy rate (CPR) and live birth rates (LBR). METHODS: Retrospective cohort study at a single fertility center at an academic institution. The peak P level and 𝚫P were modeled in relation to prediction of CPR and LBR, and the ratios of hMG:rFSH were also modeled in relation to prediction of peak P level on day of trigger, 𝚫P, and CPR/LBR in a total of 291 patients undergoing fresh embryo transfer after controlled ovarian hyperstimulation-IVF (COH-IVF). RESULTS: 𝚫P correlates with CPR, with the most predictive range for success as 𝚫P 0.7-0.85 ng/mL (p = 0.005, 95% CI 0.635, 3.636; predicting CPR of 88.9%). The optimal range for peak P in regard to pregnancy outcome was 0.15-1.349 ng/mL (p = 0.01; 95% CI for coefficient in model 0.48-3.570). A multivariable logistic model for prediction of CPR and LBR using either peak or 𝚫P supported a stronger association between 𝚫P and CPR/LBR as compared to peak P. Furthermore, an hMG:rFSH ratio of > 0.6 was predictive of lowest peak P (p = 0.010, 95% CI 0.035, 0.256) and smallest 𝚫P (p = 0.012, 95% CI 0.030, 0.243) during COH-IVF cycles. Highest CPRs were observed within hMG:rFSH ratios of 0.3-0.4 [75.6% vs. 62.5% within and outside of the range, respectively, (p = 0.023, 95% CI 0.119, 1.618)]. Highest LBRs were seen within the range of 0.3-0.6 hMG:rFSH, [LBR of 55.4% vs. 41.4% (p = 0.010, 95% CI 0.176, 1.311)]. CONCLUSIONS: Our data supports use of 𝚫P to best predict pregnancy rates and therefore can improve clinical decision making as to when fresh ET is most appropriate. Furthermore, we found optimal gonadotropin ratios can be considered to minimize P rise and to optimize CPR/LBR, emphasizing the importance of luteinizing hormone (LH) activity in COH-IVF cycles.

Human-induced pluripotent stem cell-derived ovarian support cell co-culture improves oocyte maturation in vitro after abbreviated gonadotropin stimulation.

STUDY QUESTION: Can in vitro maturation (IVM) and developmental competence of human oocytes be improved by co-culture with ovarian support cells (OSCs) derived from human-induced pluripotent stem cells (hiPSCs)? SUMMARY ANSWER: OSC-IVM significantly improves the rates of metaphase II (MII) formation and euploid Day 5 or 6 blastocyst formation, when compared to a commercially available IVM system. WHAT IS KNOWN ALREADY: IVM has historically shown highly variable performance in maturing oocytes and generating oocytes with strong developmental capacity, while limited studies have shown a positive benefit of primary granulosa cell co-culture for IVM. We recently reported the development of OSCs generated from hiPSCs that recapitulate dynamic ovarian function in vitro. STUDY DESIGN, SIZE, DURATION: The study was designed as a basic science study, using randomized sibling oocyte specimen allocation. Using pilot study data, a prospective sample size of 20 donors or at least 65 oocytes per condition were used for subsequent experiments. A total of 67 oocyte donors were recruited to undergo abbreviated gonadotropin stimulation with or without hCG triggers and retrieved cumulus-oocyte complexes (COCs) were allocated between the OSC-IVM or control conditions (fetal-like OSC (FOSC)-IVM or media-only IVM) in three independent experimental design formats. The total study duration was 1 April 2022 to 1 July 2023. PARTICIPANTS/MATERIALS, SETTING, METHODS: Oocyte donors between the ages of 19 and 37 years were recruited for retrieval after informed consent, with assessment of anti-Mullerian hormone, antral follicle count, age, BMI and ovarian pathology used for inclusion and exclusion criteria. In experiment 1, 27 oocyte donors were recruited, in experiment 2, 23 oocyte donors were recruited, and in experiment 3, 17 oocyte donors and 3 sperm donors were recruited. The OSC-IVM culture condition was composed of 100 000 OSCs in suspension culture with hCG, recombinant FSH, androstenedione, and doxycycline supplementation. IVM controls lacked OSCs and contained either the same supplementation, FSH and hCG only (a commercial IVM control), or FOSCs with the same supplementation (Media control). Experiment 1 compared OSC-IVM, FOSC-IVM, and a Media control, while experiments 2 and 3 compared OSC-IVM and a commercial IVM control. Primary endpoints in the first two experiments were the MII formation (i.e. maturation) rate and morphological quality assessment. In the third experiment, the fertilization and embryo formation rates were assessed with genetic testing for aneuploidy and epigenetic quality in blastocysts. MAIN RESULTS AND THE ROLE OF CHANCE: We observed a statistically significant improvement (∼1.5×) in maturation outcomes for oocytes that underwent IVM with OSCs compared to control Media-IVM and FOSC-IVM in experiment 1. More specifically, the OSC-IVM group yielded a MII formation rate of 68% ± 6.83% SEM versus 46% ± 8.51% SEM in the Media control (P = 0.02592, unpaired t-test). FOSC-IVM yielded a 51% ± 9.23% SEM MII formation rate which did not significantly differ from the media control (P = 0.77 unpaired t-test). Additionally, OSC-IVM yielded a statistically significant ∼1.6× higher average MII formation rate at 68% ± 6.74% when compared to 43% ± 7.90% in the commercially available IVM control condition (P = 0.0349, paired t-test) in experiment 2. Oocyte morphological quality between OSC-IVM and the controls did not significantly differ. In experiment 3, OSC-IVM oocytes demonstrated a statistically significant improvement in Day 5 or 6 euploid blastocyst formation per COC compared to the commercial IVM control (25% ± 7.47% vs 11% ± 3.82%, P = 0.0349 logistic regression). Also in experiment 3, the OSC-treated oocytes generated blastocysts with similar global and germline differentially methylated region epigenetic profiles compared commercial IVM controls or blastocysts after either conventional ovarian stimulation. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: While the findings of this study are compelling, the cohort size remains limited and was powered on preliminary pilot studies, and the basic research nature of the study limits generalizability compared to randomized control trials. Additionally, use of hCG-triggered cycles results in a heterogenous oocyte cohort, and potential differences in the underlying maturation state of oocytes pre-IVM may limit or bias findings. Further research is needed to clarify and characterize the precise mechanism of action of the OSC-IVM system. Further research is also needed to establish whether these embryos are capable of implantation and further development, a key indication of their clinical utility. WIDER IMPLICATIONS OF THE FINDINGS: Together, these findings demonstrate a novel approach to IVM with broad applicability to modern ART practice. The controls used in this study are in line with and have produced similar to findings to those in the literature, and the outcome of this study supports findings from previous co-culture studies that found benefits of primary granulosa cells on IVM outcomes. The OSC-IVM system shows promise as a highly flexible IVM approach that can complement a broad range of stimulation styles and patient populations. Particularly for patients who cannot or prefer not to undergo conventional gonadotropin stimulation, OSC-IVM may present a viable path for obtaining developmentally competent, mature oocytes. STUDY FUNDING/COMPETING INTEREST(S): A.D.N., A.B.F., A.G., B.P., C.A., C.C.K., F.B., G.R., K.S.P., K.W., M.M., P.C., S.P., and M.-J.F.-G. are shareholders in the for-profit biotechnology company Gameto Inc. P.R.J.F. declares paid consultancy for Gameto Inc. P.C. also declares paid consultancy for the Scientific Advisory Board for Gameto Inc. D.H.M. has received consulting services from Granata Bio, Sanford Fertility and Reproductive Medicine, Gameto, and Buffalo IVF, and travel support from the Upper Egypt Assisted Reproduction Society. C.C.K., S.P., M.M., A.G., B.P., K.S.P., G.R., and A.D.N. are listed on a patent covering the use of OSCs for IVM: U.S. Provisional Patent Application No. 63/492,210. Additionally, C.C.K. and K.W. are listed on three patents covering the use of OSCs for IVM: U.S. Patent Application No. 17/846,725, U.S Patent Application No. 17/846,845, and International Patent Application No.: PCT/US2023/026012. C.C.K., M.P.S., and P.C. additionally are listed on three patents for the transcription factor-directed production of granulosa-like cells from stem cells: International Patent Application No.: PCT/US2023/065140, U.S. Provisional Application No. 63/326,640, and U.S. Provisional Application No. 63/444,108. The remaining authors have no conflicts of interest to declare.

A step towards the automation of intracytoplasmic sperm injection: real time confirmation of mouse and human oocyte penetration and viability by electrical resistance measurement.

OBJECTIVE: To evaluate if oocyte penetration and viability can be confirmed by an electrical resistance increase. Automated (robotic) intracytoplasmic sperm injection (ICSI) requires confirmation of oolemma penetration before sperm injection. Visual assessment using image processing algorithms have been developed but remain unreliable. We hypothesized that an increase in electrical resistance upon oolemma piercing during ICSI can serve as an objective tool to confirm oocyte penetration and viability. DESIGN: Experimental study. SETTING: Research laboratory in an academic center. PATIENTS/ANIMALS: Oocytes from female mice and women undergoing oocyte retrieval procedure. INTERVENTION: Oolemma piercing attempts with the ICSI pipette were performed by advancing the pipette towards mature (metaphase II) oocytes collected from 6 to 12-week-old mice and immature (germinal vesicle stage and metaphase I) oocytes donated by women who underwent oocyte retrieval. Electrical resistance was measured using a conventional electrophysiological setup that includes an electrical resistance meter and two electrical wires located in the lumina of the holding and ICSI pipettes. MAIN OUTCOME MEASURE(S): The measure of interest was the change in electrical resistance (ΔR) before and after advancing the ICSI pipette in an attempt to penetrate an oocyte. The experiments of resistance measurements were done in 3 steps: Step 1 (proof of concept), penetrated vs. non-penetrated mouse oocytes. Step 2, mouse oocytes with visually intact oolemma vs. fragmented mouse oocytes. Step 3, human oocytes with visually intact oolemma vs. fragmented human oocytes. For each group, median and range (in parenthesis) of ΔR were determined in MΩ. Mann-Whitney test was performed to compare the two groups in each step. RESULTS: In Step 1, the penetrated mouse oocytes showed a statistically significant resistance increase compared to the non-penetrated ones (n = 20, median ΔR = 7.79 [2.57 - 106.00] vs. n = 15, median ΔR = 0.10 [-0.06 - 0.69], respectively. In Step 2, the mouse oocytes with visually intact oolemma showed a statistically significant resistance increase compared to the fragmented ones (n = 45, median ΔR = 6.5 [0.1 - 191.7] vs. n = 13, median ΔR = 0.1 [-0.3 - 2.2], respectively. In Step 3, the human oocytes with visually intact oolemma showed a statistically significant resistance increase compared to the fragmented ones (n = 96, median ΔR = 1.92 [-0.05 - 6.70] vs. n = 17, median ΔR = 0.11 [0.00 - 0.30], respectively. CONCLUSIONS: An electrical resistance increase can serve as a reliable tool to confirm oocyte penetration and viability, independent of optical visualization. Following further validation and safety assessment, this technology can potentially be integrated into manual and robotic ICSI systems.

Cryostorage tank failures: temperature and volume loss over time after induced failure by removal of insulative vacuum.

PURPOSE: To determine liquid nitrogen evaporation rates of intact liquid nitrogen storage tanks and tanks with their vacuum removed. METHODS: Donated storage tank performance (LN2 evaporation) was evaluated before and after induced vacuum failure. Vacuum of each tank was removed by drilling through the vacuum port. Temperature probes were placed 2 in. below the bottom of the styrofoam cap/plug, and tanks were weighed every 3 h. Evaporation rate and time from failure to the critical temperature was determined. RESULT: Storage tanks with failed vacuum have a much higher evaporation rate than those with intact vacuum; evaporation rates increased dramatically within 3 to 6 h in the smaller tanks, and time to complete depletion varied according to starting LN2 volume. Tanks with storage racks/specimens may have altered evaporation profiles compared to tanks without. Locating temperature probes 2 in. below the styrofoam cap/plug suggests that for most applications, alarms would sound approximately 1 h prior to reaching the critical warming temperature, approximately - 130 °C. External signs of vacuum loss were dramatic: vapor, frost, and audible movement of air. CONCLUSION: For the first time, we have data on how liquid nitrogen storage tanks behave when their vacuum is removed. These findings are conservative; each lab must consider starting volume, tank size/capacity, function (storage or shipping), age, and pre-existing evaporation behavior in order to develop an emergency response to critical tank failure. Times to complete failure/evaporation and critical warming temperature after vacuum loss are different; these data should be considered when evaluating tank alarm systems.