Marchante, M. | Search bioRxiv

bioRxiv2023

Improved rescue of immature oocytes obtained from conventional gonadotropin stimulation cycles via human induced pluripotent stem cell-derived ovarian support cell co-culture

Structured AbstractO_ST_ABSPurposeC_ST_ABSTo determine if rescue in vitro maturation (IVM) of human oocytes can be improved by co-culture with ovarian support cells (OSCs) derived from human induced pluripotent stem cells (hiPSCs). MethodsFertility patients undergoing conventional ovarian stimulation for oocyte cryopreservation or IVF donated denuded immature germinal vesicle (GV) and metaphase I (MI) oocytes for research, which were allocated between either the control or intervention cultures. Fertility patients aged 25 to 45 years old donated immature oocytes under informed consent, with no additional inclusion criteria. The 24-28 hour 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. Primary endpoints consisted of MII formation rate and morphological quality assessment. Additionally, metaphase spindle assembly location and oocyte transcriptomic profiles were assessed compared to in vivo matured MII oocyte controls. ResultsWe observed significant improvement in maturation outcome rates ([~]1.7X) for oocytes that underwent IVM with OSCs. Specifically, the OSC-IVM group yielded a maturation rate of 62% {+/-} 5.57% SEM versus 37% {+/-} 8.96% SEM in the Media-IVM (p=0.0138, unpaired t-test). Oocyte morphological quality between OSC-IVM and the Media-IVM control did not significantly differ. OSC-IVM resulted in MII oocytes with no instances of spindle absence and no significant difference in position compared to in vivo matured IVF-MII controls. OSC-IVM treated MII oocytes display a transcriptomic signature significantly more similar to IVF-MII controls than the Media-IVM control MII oocytes did. ConclusionThe novel OSC-IVM platform is an effective tool for rescue maturation of human oocytes obtained from conventional stimulation cycles, yielding oocytes with improved nuclear and cytoplasmic maturation. OSC-IVM shows broad utility for application in modern fertility treatment to improve the total number of available mature oocytes for fertility treatment.

developmental biology↗

bioRxiv2023

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

Assisted reproductive technologies (ART) have significantly impacted fertility treatment worldwide through innovations such as in vitro fertilization (IVF) and in vitro maturation (IVM). IVM holds promise as a technology for fertility treatment in women who cannot or do not wish to undergo conventional controlled ovarian stimulation (COS). However, IVM has historically shown highly variable performance in maturing oocytes and generating oocytes with strong developmental capacity. Furthermore, recently reported novel IVM approaches are limited to use in cycles lacking human chorionic gonadotropin (hCG) triggers, which is not standard practice in fertility treatment. We recently reported the development of ovarian support cells (OSCs) generated from human induced pluripotent stem cells (hiPSCs) that recapitulate dynamic ovarian function in vitro. Here we investigate the potential of the se OSCs in an IVM co-culture system to improve the maturation of human cumulus-enclosed immature oocytes retrieved from abbreviated gonadotropin stimulated cycles. We reveal that OSC-IVM significantly improves maturation rates compared to existing IVM systems. Most importantly, we demonstrate that OSC-assisted IVM oocytes are capable of significantly improving euploid blastocyst formation and yielding blastocysts with normal global and germline differential methylation region methylation profiles, a key marker of their clinical utility. Together, these findings demonstrate a novel approach to IVM with broad applicability to modern ART practice. Structured AbstractO_ST_ABSObjectiveC_ST_ABSTo determine if in vitro maturation (IVM) of human oocytes can be improved by co-culture with ovarian support cells (OSCs) derived from human induced pluripotent stem cells (hiPSCs). DesignThree independent experiments were performed in which oocyte donors were recruited to undergo abbreviated gonadotropin stimulation and retrieved cumulus oocyte complexes (COCs) were randomly allocated between the OSC-IVM and control IVM conditions. SubjectsAcross the three experiments, a total of 67 oocyte donors aged 19 to 37 years were recruited for retrieval using informed consent. Anti-mullerian hormone (AMH) value, antral follicle count (AFC), age, BMI, and ovarian pathology were used for inclusion and exclusion criteria. Intervention and ControlThe OSC-IVM culture condition was composed of 100,000 OSCs in suspension culture supplemented with human chorionic gonadotropin (hCG), recombinant follicle stimulating hormone (rFSH), androstenedione and doxycycline. IVM controls comprised commercially-available IVM media without OSCs and contained either the same supplementation as above (media-matched control), or FSH and hCG only (IVM media control). In one experiment, an additional control using fetal ovarian somatic cells (FOSCs) was used with the same cell number and media conditions as in the OSC-IVM. Main Outcome MeasuresPrimary endpoints consisted of metaphase II (MII) formation rate and oocyte morphological quality assessment. A limited cohort of oocytes were utilized for secondary endpoints, consisting of fertilization and blastocyst formation rates with preimplantation genetic testing for aneuploidy (PGT-A) and embryo epigenetic analysis. ResultsOSC-IVM resulted in a statistically significant improvement in MII formation rate compared to the media-matched control, a commercially available IVM media control, and the FOSC-IVM control. Oocyte morphological quality between OSC-IVM and controls did not significantly differ. OSC-IVM displayed a trend towards improved fertilization, cleavage, and blastocyst formation. OSC-IVM showed statistically significant improvement in euploid day 5 or 6 blastocyst formation compared to the commercially available IVM media control. OSC-IVM embryos displayed similar epigenetic global and germline loci profiles compared to conventional stimulation and IVM embryos. ConclusionThe novel OSC-IVM platform is an effective tool for maturation of human oocytes obtained from abbreviated gonadotropin stimulation cycles, supporting/inducing robust euploid blastocyst formation. OSC-IVM shows broad utility with different stimulation regimens, including hCG triggered and untriggered oocyte retrieval cycles, making it a highly useful tool for modern fertility treatment.

developmental biology↗