Low-quality Oocytes Research Articles

Plasma-derived exosome miR-10a-5p promotes premature ovarian failure by target BDNF via the TrkB/Akt/mTOR signaling pathway

Premature ovarian failure (POF) is characterized by a significant decline in the ovarian follicle pool and oocyte reserve, alongside an increase in the number of low-quality oocytes and apoptosis of granulosa cells (GCs). Exosome-derived miRNA plays a regulatory role in crucial cellular activities and contributes to the onset and progression of POF. In this study, we successfully established a rabbit model of POF and conducted in vitro and in vivo experiments that confirmed DiI-labeled Pla-Exos (exosomes derived from plasma) could enter the follicle through blood circulation, with GCs capable of uptaking these exosomes. Our RNA-seq analysis revealed elevated expression of miR-10a-5p in Pla-Exos from POF rabbits. Moreover, our findings demonstrate that exosomal miR-10a-5p suppresses GCs proliferation and induces apoptosis via the mitochondrial pathway. Additionally, exosomal miR-10a-5p inhibits the TrkB/Akt/mTOR signaling pathway by downregulating BDNF expression, thereby modulating the expression levels of proteins and genes associated with the cell cycle, follicle development, and GCs senescence. In conclusion, our study highlights the role of Pla-Exos miR-10a-5p in promoting rabbit POF through the TrkB/Akt/mTOR signaling pathway by targeting BDNF. These findings provide new insights into potential therapeutic targets for POF, offering valuable references for addressing concerns related to female reproductive function.

O-024 Age affects ultrasound markers of endometrial receptivity in artificial cycles

Abstract Study question Are ultrasound markers of endometrial receptivity affected by patient age in artificial cycles? Summary answer Maternal age is linked to certain ultrasound markers such as a larger uterus, reduced endometrial compaction and lower uterine peristalsis. What is known already The decline in fertility in advanced age women has traditionally been linked to low oocyte quantity and quality. However, recent studies indicate that age may also affect endometrial aspects, influencing implantation and live birth rates. Advanced age can lead to impaired decidualization, increased fibrosis and decreased expression of progesterone and estradiol receptors. This study aims to investigate the influence of age on ultrasound factors related to implantation in patients undergoing embryo transfer in artificial cycles. Study design, size, duration Retrospective study of 452 patients undergoing frozen embryo transfer with artificial cycle, between January 2017 and December 2023. Participants/materials, setting, methods Ultrasound markers were evaluated, including assessment of uterine pathology, endometrial thickness before and after the onset of progesterone and uterine peristalsis. Serum progesterone level was also analysed. Spearman correlation and multivariate linear regression were used for analysis, adjusting for uterine factors. Subgroup analysis was performed for patients aged ≥45 years. Main results and the role of chance Age correlated inversely with endometrial compaction (S range: 0.3–0.2; p = 0.01) and uterine peristalsis (S range: −0.3–0.1; p < 0.001) and positively with uterus length (S range: 0.2–0.3; p < 0.001) and fibroids. Multivariate linear regression confirmed independent associations (R=.45; p < 0.001). Logistic regression in patients aged ≥45 revealed associations with uterine peristalsis (OR 0.7, 95%CI 0.5–0.9; p = 0.04) and uterus length (OR 1.03; 95%CI 1.01-1.06) but not with endometrial compaction (p = 0.103). Limitations, reasons for caution The main limitation of the study is its retrospective nature. Being a study based on daily clinical practice, the group of patients can be heterogeneous, which may have influenced the results. Studies with a homogeneous control group are needed to corroborate our findings. Wider implications of the findings Our findings indicate that advanced maternal age affects uterine ultrasound factors, potentially influencing endometrial receptivity in artificial treatments. This may be useful to inform patients of their prognosis and to perform better clinical counseling, as well as to explore different therapeutic strategies in older patients. Trial registration number not applicable

Loss of AMPK activity induces organelle dysfunction and oxidative stress during oocyte aging

BackgroundOocyte quality is critical for the mammalian reproduction due to its necessity on fertilization and early development. During aging, the declined oocytes showing with organelle dysfunction and oxidative stress lead to infertility. AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase which is important for energy homeostasis for metabolism. Little is known about the potential relationship between AMPK with oocyte aging.ResultsIn present study we reported that AMPK was related with low quality of oocytes under post ovulatory aging and the potential mechanism. We showed the altered AMPK level during aging and inhibition of AMPK activity induced mouse oocyte maturation defect. Further analysis indicated that similar with its upstream regulator PKD1, AMPK could reduce ROS level to avoid oxidative stress in oocytes, and this might be due to its regulation on mitochondria function, since loss of AMPK activity induced abnormal distribution, reduced ATP production and mtDNA copy number of mitochondria. Besides, we also found that the ER and Golgi apparatus distribution was aberrant after AMPK inhibition, and enhanced lysosome function was also observed.ConclusionsTaken together, these data indicated that AMPK is important for the organelle function to reduce oxidative stress during oocyte meiotic maturation.

P-791 Supplementation of mitochondria from endometrial mesenchymal stem cells (EnMSCs) improves oocyte quality in aged mice

Abstract Study question To improve the quality of aging oocytes by supplementing the mitochondria from endometrial mesenchymal stem cells (EnMSCs) via microinjection. Summary answer Supplementation with EnMSC-derived mitochondria can improve the quality of oocytes and promote embryo development in aging mice. What is known already Maternal aging is one of the major causes of reduced ovarian reserve and low oocyte quality in elderly women. Decreased oocyte quality is the main cause of age-related infertility. Mitochondria are multifunctional energy stations that determine the oocyte quality. The mitochondria in aging oocytes display functional impairments with mtDNA damage, which leads to reduced competence and developmental potential of oocytes. To improve oocyte quality, mitochondrial supplementation is carried out as a potential therapeutic approach. However, the selection of suitable cells as the source of mitochondria remains controversial. Study design, size, duration Study design: Eight-month-old ICR mice were purchased and then were further raised to ten months of age for use in the experiments. EnMSCs were stably cultivated and oocytes were extracted from ten-month-old ICR mice. Study size: About 300 GV oocytes and 134 MII oocytes were counted . 80 fertilized oocytes were transplanted into the fallopian tubes of surrogate mothers. Study duraton: About one half a year. Participants/materials, setting, methods Participants:ten-month-old ICR mice. Setting and methods: We cultivated EnMSCs from aged mice and extracted mitochondria from EnMSCs. And then GV oocytes were supplemented with mitochondria via microinjection. To further assess the effects of mitochondrial supplementation on embryo development, MII oocytes from aging mice were fertilized by ICSI combining EnMSCs mitochondria microinjection.To test whether mitochondrial supplementation could improve in vivo embryo development in aging mice, embryo transplantation was performed after mitochondrial microinjection combined with ICSI. Main results and the role of chance In this study, we found that the mitochondria derived from EnMSCs could significantly improve the quality of aging oocytes.Supplementation with EnMSC mitochondria significantly increased the blastocyst ratio of MII oocytes from aging mice after intracytoplasmic sperm injection (ICSI). We also found that the birth rate of mitochondria-injected aging oocytes was significantly increased after embryo transplantation. Limitations, reasons for caution Microinjection into oocytes was invasive and some oocytes died after microinjection. The ability of this method to improve oocyte quality was limited because the MII rate of oocytes after mitochondria supplementation was 35.65±1.75% while the rate of oocytes from 6–8 weeks of mice in a previous study was nearly 80%. Wider implications of the findings For clinical treatment, the EnMSCs can be obtained from the patient's own menstrual blood as the sources of mitochondrial supplementation. A noninvasive procedure for cell extraction ensures safety, and the findings of this work might provide a valuable strategy for patients with declining oocyte quality due to aging. Trial registration number Not applicable

O-206 Growth hormone supplementation reduces aneuploidy and improves the quality of aged oocytes by activating the JAK2-ERK1/2 pathway

Abstract Study question Does growth hormone (GH) supplementation improves the quality of oocytes in aged mice via reducing aneuploidy? Summary answer Daily injections of GH for 8 weeks reduces aneuploidy by activating JAK2-ERK1/2 pathway and improves the quality of oocyte in aged mice. What is known already Aging-induced low-quality oocytes, which are mainly caused by aneuploidy, decrease female fertility. However, few treatments are available to improve the poor quality of oocytes in aged women. Age-related decline in GH levels may be related to the insufficient reproductive potential in aged women. Several studies have reported that GH improves assisted reproductive technology outcomes in poor ovarian response patients, although its role is still controversial. In animal models, GH supplementation improved the oocyte quality by enhancing mitochondrial function. However, whether GH reduces the aneuploidy rate in aged oocytes, and if so the underlying mechanisms, are unclear. Study design, size, duration The aged (8-month-old) C57BL/6J female mice were used in the study. For the in vivo experiments, the aged mice were intraperitoneally injected with GH (GenSci, Changchun, China; 1.6 mg/kg body weight) or an equivalent volume of normal saline for 8 weeks; For the in vitro experiments, germinal vesicle (GV) oocytes from aged mice were treated with GH (200 ng/mL) or PBS in M16 medium. Participants/materials, setting, methods We counted oocytes by immunohistochemistry to assess ovarian reserve. The expression of growth hormone receptor and mitochondrial genes were measured by quantitative real-time PCR. Time–lapse incubator was utilized to record the developmental potential of early embryos. Immunofluorescence was performed to assess parameters of oocyte quality (mitochondrial functions, spindle/chromosome defects, and DNA damage). Chromosome spread and DNA sequencing were used to analyze aneuploidy rate. We performed quantitative proteomics analysis to identify the potential targets of GH. Main results and the role of chance Firstly, we found that GH promoted GHR expression in aged oocytes (30.64±1.70 vs 21.68±1.08, P < 0.001). GH ameliorated aging-induced decline in ovarian reserve of aged mice, with increased ovarian index (0.040%±0.0031 vs 0.023%±0.0019, P < 0.01), and number of antral follicles (8.67±1.2 vs 3.33±0.88, P < 0.05) compared to the controls. In addition, GH improved the quality of aged oocytes, representing restored mitochondrial functions (P < 0.05), decreased DNA damage (23.37±1.76 vs 38.35±2.52, P < 0.001) . As expected, GH promoted the fertilization rate (39.9%±1.10 vs 14.4%±0.62, P < 0.001) and early embryo development (P < 0.01) of aged oocytes. Of note, GH recovered the spindle/chromosome defects (42.6%±2.12 vs 63.9%±1.83, P < 0.01, and reduced aneuploidy rate (20.9%±1.61 vs 39.3%±1.84, P < 0.01) in aged oocytes. GH activated ERK1/2 expression to decrease aneuploidy rate in aged oocytes. In addition, JAK2 might be involved in the regulation of GH on ERK1/2 expression in aged oocytes. Altogether, GH restored age-related decline in oocyte number, and decreased the occurrence rate of aneuploidy by activating JAK2-ERK1/2 pathway, thereby improving the quality of aged oocytes. Limitations, reasons for caution The molecular action mechanism of GH to regulate aneuploidy remains to be determined. Besides, future work should be extended to human oocyte to determine whether this mechanism is conserved between mice and humans Wider implications of the findings Our work expounds a theoretical basis for application of GH to improve the fertility of aged women. Besides, the results also feed new ideas for the prevention and treatment of oocyte quality decline in assisted reproductive technology. Trial registration number not applicable

Supplementation of mitochondria from endometrial mesenchymal stem cells improves oocyte quality in aged mice.

Maternal ageing is one of the major causes of reduced ovarian reserve and low oocyte quality in elderly women. Decreased oocyte quality is the main cause of age-related infertility. Mitochondria are multifunctional energy stations that determine the oocyte quality. The mitochondria in aged oocytes display functional impairments with mtDNA damage, which leads to reduced competence and developmental potential of oocytes. To improve oocyte quality, mitochondrial supplementation is carried out as a potential therapeutic approach. However, the selection of suitable cells as the source of mitochondria remains controversial. We cultivated endometrial mesenchymal stem cells (EnMSCs) from aged mice and extracted mitochondria from EnMSCs. To improve the quality of oocytes, GV oocytes were supplemented with mitochondria via microinjection. And MII oocytes from aged mice were fertilized by intracytoplasmic sperm injection (ICSI), combining EnMSCs' mitochondrial microinjection. In this study, we found that the mitochondria derived from EnMSCs could significantly improve the quality of aged oocytes. Supplementation with EnMSC mitochondria significantly increased the blastocyst ratio of MII oocytes from aged mice after ICSI. We also found that the birth rate of mitochondria-injected ageing oocytes was significantly increased after embryo transplantation. Our study demonstrates that supplementation with EnMSC-derived mitochondria can improve the quality of oocytes and promote embryo development in ageing mice, which might provide a prospective strategy for clinical treatment.

Using follicular fluid metabolomics to investigate the association between air pollution and oocyte quality

Background and aimOur objective was to use metabolomics in a toxicological-relevant target tissue to gain insight into the biological processes that may underlie the negative association between air pollution exposure and oocyte quality. MethodsOur study included 125 women undergoing in vitro fertilization at an academic fertility center in Massachusetts, US (2005–2015). A follicular fluid sample was collected during oocyte retrieval and untargeted metabolic profiling was conducted using liquid chromatography with ultra-high-resolution mass spectrometry and two chromatography columns (C18 and HILIC). Daily exposure to nitrogen dioxide (NO2), ozone, fine particulate matter, and black carbon was estimated at the women’s residence using spatiotemporal models and averaged over the period of ovarian stimulation (2-weeks). Multivariable linear regression models were used to evaluate the associations between the air pollutants, number of mature oocytes, and metabolic feature intensities. A meet-in-the-middle approach was used to identify overlapping features and metabolic pathways. ResultsOf the air pollutants, NO2 exposure had the largest number of overlapping metabolites (C18: 105; HILIC: 91) and biological pathways (C18: 3; HILIC: 6) with number of mature oocytes. Key pathways of overlap included vitamin D3 metabolism (both columns), bile acid biosynthesis (both columns), C21-steroid hormone metabolism (HILIC), androgen and estrogen metabolism (HILIC), vitamin A metabolism (HILIC), carnitine shuttle (HILIC), and prostaglandin formation (C18). Three overlapping metabolites were confirmed with level-1 or level-2 evidence. For example, hypoxanthine, a metabolite that protects against oxidant-induced cell injury, was positively associated with NO2 exposure and negatively associated with number of mature oocytes. Minimal overlap was observed between the other pollutants and the number of mature oocytes. ConclusionsHigher exposure to NO2 during ovarian stimulation was associated with many metabolites and biologic pathways involved in endogenous vitamin metabolism, hormone synthesis, and oxidative stress that may mediate the observed associations with lower oocyte quality.

Individualised versus Standard FSH Dosing in Predicted Poor Responders Undergoing IVF: A Randomised Controlled Trial

Background: Poor responders usually lead to detrimental effects on IVF outcomes due to low oocyte number and quality which further result in low pregnancy outcomes and increased chance of cycle cancellation. Clinicians often individualise the FSH dose using ovarian reserve tests (ORT), including antral follicle count (AFC). However, it is unclear whether individualised FSH dosing improves clinical outcomes. Aim: To understand if there is a difference in live birth rates between individualised or standard FSH dosing in poor responders? Method: Between March 2019 and April 2020, we performed a single center, parallel, open-label randomised controlled trial. Women referred for their first IVF/ICSI cycle, [Formula: see text]43 years of age, AFC[Formula: see text]10 were approached. Eligible women were randomised either to individualised or standard FSH dosing. In the individualised group, women with AFC 1-6 were assigned to 300IU/day, while women with AFC 7-9 were assigned to 225IU/day. In the standard group, women were assigned 150IU/day. The primary outcome was live birth attributable to the first ART cycle within 18 months of randomization. Results: A total of 661 women were randomised, 328 to the individualised group and 333 to the standard group. The live birth rate (follow up still ongoing) was not significantly different between the two groups [49.1% (161/328) vs 42.3% (141/333), RR: 1.16 (95%CI, 0.98-1.37), P=0.082]. The cumulative ongoing pregnancy rate for individualised versus standard dosing was 53.0% (174/328) versus 47.4% (158/333), respectively [RR: 1.12 (95%CI, 0.96-1.30), p=0.150]. The multiple pregnancy rate also did not differ between individualised and standard dosing [5.49% vs 5.71%, RR: 0.96 (95%CI, 0.51-1.80), p=0.903]. Individualised dosing reduced the occurrence of poor response compared to standard dosing [31.1% vs 48.6%, RR: 0.64 (95%CI, 0.53-0.78), p[Formula: see text]0.001]. Conclusion: The individualised dosing strategy led to lower rates of poor response, but it did not result in significantly higher ongoing pregnancy rates.

P-130 Morphokinetic analysis of early human embryo development and its relationship to endometriosis resection: a retrospective time-lapse study with the use of KIDScore D3 and D5

Abstract Study question Does complete resection of endometriosis improve embryo quality as assessed by morphokinetic parameters using time-lapse microscopy? Summary answer Complete resection of endometriosis in affected women undergoing assisted reproduction is shown to have a positive impact on embryo morphokinetic parameters represented in embryo quality. What is known already Endometriosis is one of the most common gynaecological diseases. It is characterized by the presence of cells comparable to those in the endometrium but being located outside of the uterine cavity. About 4-30% women of child-bearing age are affected by endometriosis. In vitro fertilization (IVF) studies have suggested that women with more advanced endometriosis have poor ovarian reserve, low oocyte and embryo quality and poor implantation rates. Moreover inflammatory peritoneal fluid shows a toxic effect on embryos. This might have an impact on morphokinetic timings but there is only limited data available concerning morphokinetics and endometriosis. Study design, size, duration 246 embryos (endometriosis group: n = 85; non-endometriosis control group: n = 115; complete resection of endometriosis= 46) undergoing infertility treatment at our clinics were included in this retrospective study. Inclusion criteria were female patients aged between 18 and 45 years undergoing IVF and / or ICSI treatment. The in vitro culture was performed in a closed time-lapse incubator (EmbryoScope®, Vitrolife) up to day 3 or in a prolonged culture up to day 5. Participants/materials, setting, methods Patient treatment included conventional insemination or intracytoplasmatic sperm injection. IVF inseminated or ICSI injected oocytes were culturd in the TimeLapse monitoring incubator. Embryos were cultured for 3 to 5 days without media change at 6.8% CO2 and 5% O2 at 37°C. During embryo culture morphokinetic parameters and events were constantly annotated. Analysis was performed using the EmbryoViewer software and evaluated applying KIDScoreTM D3 or KIDScoreTM D5 according to the day of embryo transfer. Main results and the role of chance The analysis revealed a median KIDScoreTM D5 of 2.3 (on a scale from 1 to 9.9) for embryos from patients suffering from endometriosis without complete resection. The control group without endometriosis achieved a score of 7.0 (p = 0.001). The median for embryos from endometriosis patients with complete resection was 7.1 which meant a significant increase compared to embryos from patients without complete resection (p = 0.002). Effect size according to Cohen showed a moderate up to strong biological effect (r = 0.4) for complete resection vs. no resection of endometriosis. For the three groups KIDScoreTM D3, pregnancy rates as well as abortion rates showed the same clinical trends. Additionally, we could describe a series of four patients undergoing IVF-cycles before and after a complete resection of their endometriosis. As expected, in three out of four cases they showed a clear increase in their embryo quality after complete resection of endometriosis. Limitations, reasons for caution The main limitation of the study is the relative small sample size of the groups, especially the number of patients with endometriosis resection. Additionally, the study is limited to its retrospective design. Wider implications of the findings Pathogenesis of endometriosis related infertility is multifactorial and not completely understood. But knowing that endometrioid lesions produce inflammatory cytokines which are toxic for oocytes and embryos, resection of the lesions in order to reduce inflammation seems to be a plausible approach. Trial registration number 20191007 01

What We Have Learned from Animal Models to Understand the Etiology and Pathology of Endometrioma-Related Infertility.

Endometrioma (OMA) is the most common subtype of endometriosis, in which the endometriotic lesions are implanted in the ovary. Women with OMA are usually associated with infertility, presenting with reduced ovarian reserve, low oocyte quantity and quality, and poor fertility outcomes. However, the underlying pathological mechanisms in OMA-related infertility are still unclear. Due to the limitations and ethical issues of human studies in reproduction, animal models that recapitulate OMA characteristics and its related infertility are critical for mechanistic studies and subsequent drug development, preclinical testing, and clinical trials. This review summarized the investigations of OMA-related infertility based on previous and latest endometrioma models, providing the possible pathogenesis and potential therapeutic targets for further studies.

Follicular Fluid: A Powerful Tool for the Understanding and Diagnosis of Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) represents one of the leading causes of anovulatory infertility and affects 5% to 20% of women worldwide. Until today, both the subsequent etiology and pathophysiology of PCOS remain unclear, and patients with PCOS that undergo assisted reproductive techniques (ART) might present a poor to exaggerated response, low oocyte quality, ovarian hyperstimulation syndrome, as well as changes in the follicular fluid metabolites pattern. These abnormalities originate a decrease of Metaphase II (MII) oocytes and decreased rates for fertilization, cleavage, implantation, blastocyst conversion, poor egg to follicle ratio, and increased miscarriages. Focus on obtaining high-quality embryos has been taken into more consideration over the years. Nowadays, the use of metabolomic analysis in the quantification of proteins and peptides in biological matrices might predict, with more accuracy, the success in assisted reproductive technology. In this article, we review the use of human follicular fluid as the matrix in metabolomic analysis for diagnostic and ART predictor of success for PCOS patients.

Increased versus standard gonadotrophin dosing in predicted poor responders of IVF: an open-label randomized controlled trial.

Does an increased dosing of FSH improve the live birth rate as compared to standard FSH dosing in expected poor responders who undergo IVF? In this trial, women with an expected poor response allocated to increased FSH dosing did not have a statistically significant increase in cumulative live births as compared to a standard FSH dose. Poor ovarian reserve leads to worse IVF outcomes owing to the low number and quality of oocytes. Clinicians often individualize the FSH dose using ovarian reserve tests, including antral follicle count (AFC), and basal plasma FSH or anti-Müllerian hormone level. However, the evidence that increased FSH dosing improves fertility outcomes in women with an expected poor response is lacking. We performed a parallel, open-label randomized controlled trial between March 2019 and October 2021 in an assisted reproduction centre. Women <43 years of age with AFC <10 referred for their first IVF cycle were randomized for increased or standard FSH dosing. In participants allocated to increased FSH dosing, women with AFC 1-6 started with 300 IU/day, while women with AFC 7-9 started with 225 IU/day. In participants allocated to the standard care, women started with 150 IU/day. The primary outcome was cumulative live birth attributable to the first IVF cycle including fresh and subsequent frozen-thawed cycles within 18 months of randomization. Live birth was defined as the delivery of one or more living infants ≥24 weeks' gestation. This trial was powered to detect an 11% difference in live birth attributable to the first IVF cycle. Outcomes were evaluated from an intention-to-treat perspective. We randomized 661 women to start FSH at increased dosing (n = 328) or standard dosing (n = 333). The primary outcome cumulative live birth occurred in 162/328 (49.4%) women in the increased group versus 141/333 (42.3%) women in the standard group [risk ratio (RR) 1.17 (95% CI, 0.99-1.38), risk difference 0.07 (95% CI, -0.005, 0.15), P = 0.070]. The live birth rate after the first embryo transfer in the increased versus standard group was 125/328 (38.1%) versus 117/333 (35.1%), respectively [RR 1.08 (95% CI, 0.83-1.33), P = 0.428]. Cumulative clinical pregnancy rates were 59.1% versus 57.1% [RR 1.04 (95% CI, 0.91-1.18), P = 0.586] with miscarriage rates of 9.8% versus 14.4% [RR 0.68 (95% CI, 0.44-1.03), P = 0.069] in the increased versus standard group, respectively. Other secondary outcomes, including biochemical pregnancy, ongoing pregnancy, multiple pregnancy and ectopic pregnancy, were not significantly different between the two groups both from the first and cumulative embryo transfer. As this study is open-label, potential selective cancelling and small dose adjustments could have influenced the results. In women with predicted poor response, we did not find evidence that increased FSH dosing improves live birth rates. A standard dose of 150 IU/day is recommended at the start of IVF in these women to reduce potential adverse effects and costs. This study was funded by the General Projects of Social Development in Shaanxi Province (No. 2022SF-565). B.W.M. is supported by NHMRC (GNT1176437). B.W.M. reports personal fees from ObsEva, and funding from Merck and Ferring outside the submitted work. Registered at Chinese clinical trial registry (www.chictr.org.cn). Registration number ChiCTR1900021944. 17 March 2019. 20 March 2019.

Aberrant Expression of Mitochondrial SAM Transporter SLC25A26 Impairs Oocyte Maturation and Early Development in Mice.

The immature germinal vesicle (GV) oocytes proceed through metaphase I (MI) division, extrude the first polar body, and become mature metaphase II (MII) oocytes for fertilization which is followed by preimplantation and postimplantation development until birth. Slc25a26 is the gene encoding S-adenosylmethionine carrier (SAMC), a member of the mitochondrial carrier family. Its major function is to catalyze the uptake of S-adenosylmethionine (SAM) from cytosol into mitochondria, which is the only known mitochondrial SAM transporter. In the present study, we demonstrated that excessive SLC25A26 accumulation in mouse oocytes mimicked naturally aged oocytes and resulted in lower oocyte quality with decreased maturation rate and increased reactive oxygen species (ROS) by impairing mitochondrial function. Increased level of Slc25a26 gene impacted gene expression in mouse oocytes such as mt-Cytb which regulates mitochondrial respiratory chain. Furthermore, increased level of Slc25a26 gene in fertilized oocytes slightly compromised blastocyst formation, and Slc25a26 knockout mice displayed embryonic lethality around 10.5 dpc. Taken together, our results showed that Slc25a26 gene plays a critical role in oocyte maturation and early mouse development.

O-174 Individualized versus standard FSH dosing in predicted poor responders: an RCT

Abstract Study question Is there a difference in fertility outcomes between individualized or standard FSH dosing in women scheduled for IVF with an expected poor response? Summary answer In predicted poor responders (AFC&amp;lt;10) undergoing IVF/ICSI, individualized FSH dosing does not improve ongoing pregnancy rates as compared to a standard FSH dose. What is known already Poor responders usually lead to many detrimental effects on IVF outcomes due to low oocyte number and quality which in turn result in low pregnancy outcomes and an increased chance of cycle cancellation. Clinicians often individualize the FSH dose using ovarian reserve tests (ORT), including antral follicle count (AFC), basal FSH (bFSH), and anti-Mullerian hormone (AMH). However, it is unclear whether individualized FSH dosing improves clinical outcomes. Study design, size, duration Between March 2019 and April 2020, we performed a single-center, parallel, open-label RCT in women with an AFC&amp;lt;10. A total of 661 women were randomized either to start FSH dosing at 300IU/225IU or 150IU. The primary outcome was live birth attributable to the first ART cycle within 18 months of randomization. In this abstract, we report ongoing pregnancy rates. Live birth date will be available at the meeting. Participants/materials, setting, methods Women referred for their first IVF/ICSI cycle, &amp;lt;43 years of age, AFC&amp;lt;10 were approached. A total of 328 women were allocated to the individualized group and 333 women were allocated to the standard group. In the individualized group, women with AFC 1-6 were assigned to 300IU/day (n = 122), while women with AFC 7-9 were assigned to 225IU/day (n = 206). In the standard group, women were assigned 150IU/day. Outcomes were evaluated from an intention-to-treat perspective. Main results and the role of chance For ongoing pregnancy rate attributable to the first ART cycle for individualized versus standard dosing was comparable [52.44% vs 46.25%, relative risk (RR): 1.29 (95%CI, 0.94-1.74), P = 0.11]. Biochemical pregnancy rate [62.50% vs 62.16%, RR: 1.01 (95%CI, 0.74-1.39), P = 0.929], clinical pregnancy rate [59.45% vs 58.86%, RR: 1.02 (95%CI, 0.75-1.40), P = 0.877] and multiple pregnancy rate [5.18% vs 5.12%, RR: 1.01 (95%CI, 0.51-2.02), P = 0.971] also did not differ between individualized and standard dosing. There are 24 women who are ongoing pregnancy but do not reach live birth in the completed embryo transfer cycle. The individualized group reported less poor response (31.1% vs 48.7%: P &amp;lt; 0.001), more obtained oocytes (6.80 ± 3.85 vs 5.28 ± 3.22; P &amp;lt; 0.001), less embryos (3.76 ± 2.70 vs 3.16 ± 2.42; P = 0.004), and less good quality embryos (2.61 ± 2.29 vs 2.21 ± 2.05; P = 0.018). When outcomes were compared over the first embryo transfer, ongoing pregnancy rates were 39.0% (128/328) versus 37.2% (124/333), respectively [RR:1.08 (95%CI, 0.79-1.48), P = 0.636], without differences in the other outcomes. There are 7 women who are ongoing pregnancy but do not reach live birth in the first embryo transfer cycle. Limitations, reasons for caution Due to the open-label character, potential selective canceling and small dose adjustments of standard dosing were allowed. This abstract reports on ongoing pregnancy. At the meeting, we will present live birth rates. Wider implications of the findings In women with predicted poor response, an increased dose does not increase ongoing pregnancy rates. A standard dose of 150IU/day is recommended in these women. Trial registration number ChiCTR1900021944

O-209 The impact of sperm DNA fragmentation on pregnancy outcomes depends on oocyte dimorphisms

Abstract Study question Does the impact of sperm DNA fragmentation (SDF) on Intracytoplasmic sperm injection (ICSI) outcomes depend on the presence of oocyte dimorphisms? Summary answer There is a significant influence of oocyte quality on the impact of SDF on pregnancy outcomes. What is known already Sperm DNA fragmentation has been associated with ICSI outcomes. DNA damage is commonly encountered in human spermatozoa and it has been widely accepted that the oocyte assumes responsibility for the repair and remodelling of both the maternal and paternal genomes during the oocyte-embryo transition. Indeed, spermatozoa with DNA damage can fertilise oocytes and still lead to embryo development due to the oocyte DNA repair capacity. Considering the vital role played by the oocyte in the developmental process, it could be hypostatised that the oocyte quality, translated as oocyte morphology, would influence the machinery responsible for sperm DNA repair after fertilization. Study design, size, duration This cohort study included 3,035 oocytes from 525 patients undergoing ICSI cycles in a university-affiliated IVF-center, between June/2016 and July/2019. Oocytes were split into groups according to the SDF index of the sample used for ICSI: low-fragmentation (&amp;lt;30% SDF, n = 2,277) and high-fragmentation (≥30% SDF, n = 758). Oocytes were evaluated before sperm injection and the dimorphisms were recorded. The influence of SDF index on ICSI outcomes, depending on the presence of oocytes dimorphisms was evaluated. Participants/materials, setting, methods Data was evaluated using generalized linear models (GZLM) followed by Bonferroni post hoc. The results are expressed as mean ± standard error for continuous variables or percentages for dichotomous variables, and p-values. The sample size calculation suggested that a sample of at least 504 subjects had 95% power to detect a 20% effect with a significance level of 5% (α). The study was performed in a private university–affiliated in vitro fertilization (IVF) center. Main results and the role of chance The association of both factors: the presence of oocyte dimorphisms (dark cytoplasm, vacuoles in the ooplasm, and resistant membrane) and high SDF index resulted in the lowest fertilization rate among groups, while oocytes free of these dimorphisms injected with samples with &amp;lt;30% SDF had the highest fertilization rate (p = 0.05, p &amp;lt; 0.01 and p &amp;lt; 0.01 for dark cytoplasm, vacuoles in the ooplasm and resistant membrane respectively). The impact of SDF index on high quality embryos rate on cleavage stage was also influence by the presence smooth endoplasmic reticulum clusters and resistant membrane oocytes (p = 0.013 and p = 0.018). As for the clinical outcomes, the impact of SDF index on the implantation rate was influenced by the presence of vacuoles in the ooplasm (p &amp;lt; 0.01), smooth endoplasmic reticulum clusters (p &amp;lt; 0.01), large perivitelline space (p &amp;lt; 0.01), resistant membrane (p &amp;lt; 0.01), and non-resistant membrane (p &amp;lt; 0.01), while the influence of SDF index on the pregnancy rate was influenced by the presence large perivitelline space (p &amp;lt; 0.01), resistant membrane (p = 0.018) and non-resistant membrane (p &amp;lt; 0.01). The effect of SDF on the miscarriage rate was also increased in the presence of large perivitelline space (p = 0.045), non-resistant membrane (0.037) and centrally located cytoplasmic granular area (p = 0.025). Limitations, reasons for caution The retrospective nature is a limitation. It could be argued that using samples with high SDF index does not necessarily mean that a sperm cell with a fragmented DNA was injected, however, the higher the SDF index, the higher the chance of selecting one with fragmented DNA. Wider implications of the findings The findings presented here highlight the crucial role of male and female factors when facing assisted reproduction. The association of low oocyte quality and high SDF index may lead to impaired results. As the oocyte defect cannot be modified, in vivo upgrading of spermatozoa before the treatment should be encouraged. Trial registration number Not applicable

P–245 Machine learning predicting oocyte’s fertilization and blastocyst potential based on morphological features

Abstract Study question Can machine learning (ML) predict oocyte’s fertilization and blastocyst development potential based on morphological features extracted from single static images? Summary answer AI accurately predicted 70.4% of fertilization and 60.4% of blastocyst development outcomes from a database of 1000 oocytes. What is known already Some morphological features of the oocyte have been associated with IVF-related outcomes, such as size, shape, and coloration of zona pellucida, polar body, perivitelline space, cytoplasm, and the meiotic spindle. Based on these characteristics, clinics might discard the low-quality oocytes according to a subjective assessment. AI-based algorithms could reduce the subjectivity and improve prediction on IVF outcomes such as successful fertilization and blastocyst development. Study design, size, duration Non-intervention study based on a cohort of 1000 oocytes’ micrographs collected between January 2019 and December 2020 from two IVF clinics. The inclusion criteria were known fertilization and blastocyst development outcome, and patient’s age between 25 and 45 years old undergoing IVF/ICSI treatment. Different features were considered for this study including metadata from oocyte’s (e.g. age, source), as well as manually extracted morphological features from the oocytes’ images (e.g. diameters, shape, granularity, presence/absence of spindle). Participants/materials, setting, methods We trained three machine-learning (ML) classifiers (i.e. Support Vector Machine, logistic regression, and neural networks) to predict successful fertilization and blastocyst development. For the training process we used a 10-fold cross validation approach to assess the model’s generalization capabilities. Besides we tested the statistical difference of each feature among groups (i.e. fertilized and no fertilized) using a two sided Student’s t-test for numerical and Z-test for categorial features (significance of p &amp;lt; 0.01). Main results and the role of chance Our database showed 68.2% of successful fertilization and 34.8% of blastocyst formation. To balance the training data (50% per training class), we aleatory selected 318 and 348 samples per branch of successful/unsuccessful fertilization and blastocyst formation, respectively. From all ML classifiers, the neural network obtained the best results with an accuracy of 0.70 (AUC of 0.74) for predicting fertilization; and an accuracy of 0.60 (AUC of 0.62), for predicting blastocyst formation. We found that spherical shape, presence of meiotic spindle, clear coloration, larger oocyte diameter, thicker zona pellucida, and smaller vacuoles are statistically associated with both successful outcomes. As expected, we also found a strong association between age groups and outcome. The younger group (&amp;lt;35 years) demonstrated to have a larger proportion of successful fertilization compared to the rest of the age groups (36–37, 38–39, 40–42, &amp;gt;42). For the blastocyst formation we observed a similar association. Limitations, reasons for caution It is relevant to note that all cycles were performed under a mini-IVF protocol. Oocytes extracted through conventional stimulation might show the same associations, but it would need further testing. Wider implications of the findings: The present study revealed that our system can predict fertilization success and blastocyst development potential based on metadata and morphometric features extracted from single digital micrographs of oocytes, offering a novel, adaptable and robust integration into clinical practice. Trial registration number CONBIOETICA–09-CEI–001–2017–0131

A Nuclear and Cytoplasmic Characterization of Bovine Oocytes Reveals That Cysteamine Partially Rescues the Embryo Development in a Model of Low Ovarian Reserve.

Decreased oocyte quality is a major determinant of age-associated fertility decline. Similarly, individuals affected by early ovarian aging carry low-quality oocytes. Using an established bovine model of early ovarian aging, we investigated key features of 'quality' oocyte maturation, associated with the onset of egg aneuploidy and reproductive aging, such as histone modifications, mitochondria distribution and activity, reduced glutathione (GSH) content, and gap junction functionality. Bovine ovaries were classified according to the antral follicle count (AFC), and the retrieved oocytes were processed immediately or matured in vitro. We observed alterations in several cellular processes, suggesting a multifactorial etiology of the reduced oocyte quality. Furthermore, we performed a rescue experiment for one of the parameters considered. By adding cysteamine to the maturation medium, we experimentally increased the free radical scavenger ability of the 'low competence' oocytes and obtained a higher embryo development. Our findings show that adopting culture conditions that counteract the free radicals has a positive impact on the quality of 'compromised' oocytes. Specifically, cysteamine treatment seems to be a promising option for treating aging-related deficiencies in embryo development.

The rate of oocytes with granular cytoplasm is higher in women with endometrioma in ICSI cycles

The purpose of this study was to investigate the impact of endometrioma on oocyte morphology and fertility outcome in intracytoplasmic sperm injection (ICSI)cycles. The study material was obtained from 114 ICSI cycles of infertile women aged between 20 and 38 years with ovarian endometriomas and unexplained infertility. In total, 644 mature oocytes were included in the analysis. The rates of specific oocyte morphological abnormalities were similar between the two groups however the central granulation rate was significantly higher in the group with endometrioma (p < .05). Fertilisation rate were not significantly different between the groups (p ≥ .05) however the numbers of metaphase 2 (MII) oocytes and embryos were lower in the endometrioma group (p ≤ .05). Endometrioma was associated with a higher rate of oocytes with granular cytoplasm, despite the fertilisation rate the numbers of the MII oocytes and embryo were affected. IMPACT STATEMENT What is already known on this subject? The association between endometrioma and infertility is a well-known condition, but the possible mechanisms of the effects of endometrioma on women's fertility is still debated and controversial. There is limited data on the effect of endometrioma on oocyte morphology. Low oocyte quality and lower fertilisation rates might be the main cause of adverse pregnancy outcomes during in vitro fertilisation/intracytoplasmic sperm injection cycles. What do the results of this study add? Endometrioma was associated with a higher rate of oocytes with granular cytoplasm, and lower metaphase 2 oocytes and embryos. What are the implications of these findings for clinical practice and/or further research? Future studies using further oocyte quality assessment methods and prospective observational studies including live-birth rate should be designed to better understand how endometrioma affects fertility outcomes.

Cellular and molecular alterations of buffalo oocytes cultured under two different levels of oxygen tension during in vitro maturation.

This study was conducted to monitor the cellular and molecular changes of buffalo cumulus-oocytes complexes (COCs) cultured under high or low oxygen levels. Morphologically good quality COCs (n = 1627) were screened using brilliant cresyl blue (BCB) staining and placed into three groups (BCB+, BCB- and control). All groups of COCs were cultured under low (5%) or high (20%) oxygen tensions. Intracellular and molecular changes including oocyte ultrastructure, lipid contents, mitochondrial activity and transcript abundance of genes regulating different pathways were analyzed in the matured oocyte groups. The results revealed that oxygen tension did not affect cumulus expansion rates, however the BCB+ group had a higher (P ≤ 0.05) expansion rate compared with the BCB- group. BCB- oocytes recorded the lowest meiotic progression rate (P ≤ 0.05) under high oxygen levels that was linked with an increased level of reactive oxygen species (ROS) compared with the BCB+ oocytes. Ultrastructure examination indicated that BCB+ oocytes had a higher rate of cortical granules migration compared with BCB- under low oxygen tension. In parallel, our results indicated the upregulation of NFE2L2 in groups of oocytes cultured under high oxygen tension that was coupled with reduced mitochondrial activity. In contrast, the expression levels of MAPK14 and CPT2 genes were increased (P ≤ 0.05) in groups of oocytes cultured under low compared with high oxygen tension that was subsequently associated with increased mitochondrial activity. In conclusion, data from the present investigation indicated that low oxygen tension is a favourable condition for maintaining the mitochondrial activity required for nuclear maturation of buffalo oocytes. However, low-quality oocytes (BCB-) responded negatively to high oxygen tension by reducing the expression of gene-regulating metabolic activity (CPT2). This action was an attempt by BCB- oocytes to reduce the increased levels of endogenously produced ROS that was coupled with decreased expression of the gene controlling meiotic progression (MAPK14) in addition to nuclear maturation rate.

Fshr and lhr mRNA expression in granulosa cells of poor responder

In Vitro Fertilization (IVF) is one of the most commonly used procedures to help pregnancies in couples who have infertility problems. One of the problems of infertility is poor ovarian response and the woman who experiences it is known as poor responder. Poor responders do not have an adequate ovarian response to gonadotropin in ovarian stimulation. The success of fertilization in poor responders tends to be low due to low quantity and is generally followed by low oocyte quality. Gonadotropins consisting of FSH and LH, play a role in follicle development and ovulation. The follicle response in capturing gonadotropins depends on the exact bond between the hormone and its receptor (FSHR and LHR) in the granulosa cells surrounding the oocyte. The purpose of this research is to know the expression level of fshr and lhr mRNA in granulosa cells of poor responders through real-time PCR method which then tested statistically using t-test. Fourteen samples of each poor responders and normal women were used in this research. The results showed insignificant differences between expression level of fshr and lhr mRNA in granulosa cells of poor responders and normal women (p > 0.05).