Oocyte Fertilization Research Articles

The Kisspeptin and Kisspeptin receptor in follicular microenvironment: is that really necessary for oocyte maturation and fertilisation?

The aim of this study was to determine whether Kisspeptin and Kisspeptin receptor in the follicular microenvironment is necessary for human oocyte maturation and fertilisation. The cumulus cell (CC) and follicle fluids (FF) obtained from the first aspirated follicles (n = 52) from 32 patients were divided into three groups considering nuclear maturation and fertilisation results of oocytes: (1) Metaphase I or germinal vesicle stage oocytes (incomplete nuclear maturation, n = 10), (2) unfertilised metaphase II oocytes (incomplete cytoplasmic maturation, n = 16), and (3) fertilised metaphase II oocytes (completed nuclear-cytoplasmic maturation, n = 26). The gene expression levels were assessed by RT-PCR. The levels of Kisspeptin (KISS1) and Kisspeptin receptor (KISS1R) were measured by ELISA. There were no significant efficacy KISS1 and KISS1R gene expressions in cumulus cells in terms of oocyte nuclear maturation stage (Group 1, vs Group 2 + Group 3) (respectively p = .49; p = .45). In terms of the cytoplasmic maturation stage (Group 2, vs Group 3); KISS1 and KISS1R expressions in CCs were comparable (respectively p = .07; p = .08). In FFs, KISS1 and KISS1R concentrations were similar between all groups (respectively p = .86; p = .26). In conclusion, the relative KISS1 and KISS1R expressions in CC and also KISS1 and KISS1R level of FF were independent of oocytes nuclear and/or cytoplasmic maturation. Impact statement What is already known on this subject? It has been demonstrated that Kisspeptin is an essential regulator of reproductive function and plays a key role in the modulation of GnRH secretion and gonadotropin release. Still, no information is available about the link between gene expression or concentration in the follicular microenvironment and oocyte development. What do the results of this study add? The study has shown that the relative Kisspeptin (KISS1) and Kisspeptin receptor (KISS1R) and expressions in cumulus cell (CC) and also KISS1 and KISS1R levels of follicle fluids (FF) were independent of oocytes nuclear and/or cytoplasmic maturation. What are the implications of these findings for clinical practice and/or further research? Based on the findings, it is difficult to establish a concept that kisspeptin can directly induce oocyte maturation. Nevertheless, to confirm these findings, further studies with a larger sample size are needed.

Letrozole cotreatment with progestin-primed ovarian stimulation in women with polycystic ovary syndrome undergoing IVF treatment.

Background: Progestin is an alternative to gonadotropin-releasing hormone (GnRH) analogues in the follicular phase to suppress the premature luteinizing hormone (LH) surge in women with polycystic ovary syndrome (PCOS). However, progestin-primed ovarian stimulation (PPOS) is always accompanied by increased pituitary suppression and gonadotropin consumption. Previous studies suggested that letrozole appeared to have the potential to reduce the total gonadotropin dose required for ovarian stimulation. A retrospective cohort study was performed to evaluate the efficacy of PPOS with or without letrozole in infertile women with PCOS. Methods: This retrospective cohort study included 448 women with PCOS who underwent controlled ovarian stimulation (COS) with human menopausal gonadotropin (hMG) and medroxyprogesterone acetate (MPA) (n = 224) or hMG and MPA cotreatment with LE (n = 224) from January 2018 to March 2021 after propensity-score matching. The primary outcome measure was the hMG dose. The secondary outcomes were the durations of ovarian stimulation, the implantation rate, the number of oocytes retrieved and viable embryos, oocyte maturity and fertilization rates, the percentage of women with profound pituitary suppression (luteinizing hormone [LH] <1.0 IU/L on the trigger day). Results: The hMG doses (1949.89 ± 725.03 IU vs 2017.41 ± 653.32 IU, p > 0.05) and durations of ovarian stimulation (9.03 ± 1.79 days vs 9.21 ± 2.18 days, p > 0.05) were similar between the two groups. The implantation rate was significantly higher in the study group (MPA + hMG + LE) than in the control group (MPA + hMG) (42.22 vs 34.69%, p < 0.05). The numbers of oocytes and embryos retrieved were similar between the two groups. Interestingly, letrozole cotreatment was associated with decreased oocyte maturity and fertilization rates in comparison with standard PPOS protocols even though mature and fertilized oocyte yields were comparable. Compared with those in the control group, the LH values on the trigger day were significantly higher in the study group, together with significantly reduced pituitary suppression. Conclusion: Letrozole combined with PPOS cannot reduce hMG consumption in PCOS patients undergoing IVF treatment and shows no beneficial effect on cycle characteristics of COS. However, letrozole supplementation manifests as a superior implantation rate to that of the standard PPOS protocol in women with PCOS.

The influence of paternal overweight on sperm chromatin integrity, fertilization rate and pregnancy outcome among males attending fertility clinic for IVF/ICSI treatment

BackgroundLow and middle-income countries are facing a rapid increase in obesity and overweight burden, particularly in urban settings. Being overweight in men is associated with infertility and a higher risk to have a low sperm count or no sperm in their ejaculate. Despite potential limitations, this is one of few studies conducted to determine the potential risk of paternal overweight on sperm standard parameters, sperm chromatin integrity and assisted conception outcome including fertilization, embryo quality, cleavage rate, reduce blastocyst development, implantation, and cumulative live birth rate (CLBR).MethodsA cross-sectional study of 750 infertile couples undergoing assisted reproduction technique at a single reproductive medicine center of Salma Kafeel Medical Centre Islamabad. Sperm from men undergoing ART were analyzed for chromatin integrity using sperm chromatin dispersion assay (SCD), Chromomycin A3 staining (CMA3), and toluidine blue (TB) staining, while other semen parameters were assessed on same day includes; standard semen parameters, reactive oxygen species (ROS), sperm deformity index (SDI), teratozoospermic index (TZI), and hypo-osmatic swelling test (HOST). Paternal body mass index (BMI) < 24.5–20 kg/m2 served as the reference group, while the male patients with BMI > 24.5-30 kg/m2 were considered to be overweight.ResultsIn the analysis of the percentage of spermatozoa with chromatin maturity (CMA3) and chromatin integrity (TB) was reduced significantly in overweight men (p < 0.01) compared with a reference group. Increase in paternal BMI correlate with the increase in sperm chromatin damage (SCD r = 0.282, TB r = 0.144, p < 0.05), immaturity (CMA3, r = 0.79, p < 0.05) and oxidative stress (ROS) (r = 0.282, p < 0.001). Peri-fertilization effects were increased in oocytes fertilization in couples with overweight men (FR = 67%) compared with normal-weight men (FR = 74.8%), similarly, after univariant regression paternal weight remain predictor of sperm chromatin maturity, successful fertilization and CLBR. In the embryo, developmental stage number of the embryo in cleavage was higher in normal weight men, while day 3 (D3) embryos, percent good quality embryo D3, and blastocyst formation rate were compared able between the groups. The paternal overweight group had significant (p < 0.001) increased neonatal birth weight (2952.14 ± 53.64gm; within normal range) when compared with the reference group (2577.24 ± 30.94gm) following assisted reproductive technology (ART). CLBR was higher (p < 0.05) in normal weight men compared to couples with overweight male partners. CLBR per embryo transfer and per 2PN was a statistically significant (p < 0.05) difference between the two groups. An inverse association was observed in the linear regression model between paternal BMI with fertilization rate and CLBR.ConclusionThe present study demonstrated the impact of paternal overweight on male reproductive health, as these patients had a higher percentage of immature sperm (CMA3) with impaired chromatin integrity (SCD, TB) in their semen and had decreased fertilization rate, CLBR following assisted reproductive treatments. The present study supports that paternal overweight should be regarded as one of the predictors for fertilization, CLBR and useful for counseling, to consider body mass index not only in women but also for men, in those couples opting for ART treatment, and warrant a poor reproductive outcome in overweight men.

Uso de biotecnologías reproductivas para mejorar la fertilidad de vacas lecheras repetidoras y con estrés por calor

Cows that do not become pregnant during early lactation after successive inseminations are usually classified as repeat-breeder cows. Furthermore, heat stress has a pronounced deleterious effect on fertility in dairy herds throughout the world, especially in hot and humid summer months in tropical and subtropical areas. Studies describes the detrimental effect of heat stress on reproduction, with emphasis on carry over effects of heat stress on oocyte quality, embryo development and P/AI. Additionally, lower fertilization rate is also an important characteristic associated with repeatbreeder cows. In repeat-breeder cows, decreased fertility has been related to a deleterious effect on oocyte quality. Thus, the fertility problems observed in repeat-breeder and heat stress cows may be related to poor oocyte quality associated with a metabolic status. Studies support thar embryo transfer can be a practical and effective solution to achieve pregnancy in repeat-breeder and heatstressed dairy cows (with reduced oocyte quality and fertility to insemination).

EXPRESIÓN HETEROLOGA DE LA ESPERMADHESINA-1 BOVINA MEDIANTE Escherichia coli COMO BIOFÁBRICA

Seminal plasma proteins (SPP) are fundamental for oocyte fertilization by sperm cells. In bovine, the structure and function of SPP have been widely described in several studies, where the spermadhesin family has been highlighted. Spermadhesin proteins are closely related to sperm motility and viability along with protecting the sperm cells against oxidative stress. Spermadhesin-1, also known as acidic Seminal Fluid Proteins (aSFP), exhibits a redox activity that protects the sperm cells from reactive oxygen species (ROS), an important feature that could be taken in advantage to improve the postthaw seminal quality of sperm cells after cryopreservation processes. Therefore, the aim of this research was to produce heterologous aSFP using Escherichia coli as a cell factory. For this purpose, the DNA sequence of aSFP was inserted into a pDAss plasmid, containing a six-histidine tag (6xhis). The obtained construct was used to transform BL21 (DE3) E. coli competent cells. The expression trials were developed at three different temperatures (37°,25°, and 16°C) and two different concentrations of Isopropyl-β-D-1-thiogalactopiranoside (IPTG) as the expression inductor (0.5 y 1.0 mM). The aSFP-H6 produced was purified by affinity chromatography, and the peptide sequence was verified through mass spectrometry. Results evidenced the best conditions for the recombinant aSFP-H6 production (16°C and 1.0 mM of IPTG). In this sense, the viability and the conditions to produce heterologous bovine aSFP were described and could be further used to enhance cryopreservation bovine sperm mediums.

Comparative study between general anesthesia and conscious sedation for oocyte retrieval on hemodynamic recovery and oocyte quality

Background: In vitro fertilization (IVF) is a four-stage procedure, ovarian stimulation and monitoring, oocyte retrieval, fertilization and embryo transfer. Transvaginal ultrasound–guided follicle aspiration is the most common method for oocyte retrieval in assisted reproductive technologies, it is increasingly performed as an outside procedure. Objective: To compare between general Anesthesia and Conscious Sedation according to Oocyte Retrieval on hemodynamic recovery and oocyte quality. Methods: Seventy women underwent oocyte retrieval in the period from November 2021 till June 2022 at High Institute of Infertility Diagnosis and Assisted Reproductive Technique, Reproductive Physiology, Al-Nahrain University in Baghdad, Iraq, were included in this study. Results: Mean time needed for operation was 9.06± 1.39 minutes in conscious group and 9.84± 1.11 minutes in GA group, and the recovery time needed was 2.31± 0.47 hours in conscious group and 10.78± 1.87hours in GA group. Conclusion: Significant decrease in duration of operation in conscious group than that in general anesthesia group (P=0.01), moreover, highly significant decrease in recovery time in conscious group than that in GA group (P&lt;0.001)

Gene mutations impede oocyte maturation, fertilization, and early embryonic development.

Reproductive diseases are a long-standing problem and have become more common in the world. Currently, 15% of the world's population suffers from infertility, and half of them are women. Maturation of oocytes, successful fertilization, and high-quality embryos are prerequisites for pregnancy. With the development of assisted reproductive technology and advanced genetic assays, we have found that infertility in many young female patients is caused by mutations in various developmental regulators. These pathogenic factors may result in impediment of oocyte maturation, failure of fertilization or early embryonic development arrest. In this review, we categorize these clinically-identified, mutated genetic factors by their molecular characteristics: nuclear factors (PALT2, TRIP13, WEE2, TBPL2, REC114, MEI1 and CDC20), cytoplasmic factors (TLE6, PADI6, NLRP2/5, FBXO43, MOS and BTG4), a factor unique to primates (TUBB8), cell membrane factor (PANX1), and zona pellucida factors (ZP1-3). We compared discrepancies observed in phenotypes between human and mouse models to provide clues for clinical diagnosis and treatment of related reproductive diseases.

Effect of Taurine and Curcumin on In-Vitro Fertilization in NMRI Mice Treated with Acrylamide

Introduction: The aim of this study was to evaluate the effect of taurine and curcumin on in vitro fertilization (IVF) in female mice treated with acrylamideand and its effect on malondialdehyde (MDA) concentration and total antioxidant capacity (TAC).&#x0D; Methods: A total of 48 adult female NMRI mice were randomly divided into 6 groups, including control, curcumin 200 mg / kg, taurine 150 mg / kg, acrylamide 5 mg / kg, acrylamide 5 mg / kg + curcumin 100 and 200, acrylamide 5 mg / kg + Taurine 75 and 150 mg / kg. The drugs were administered orally for 35 days, and then IVF rate, MDA and TAC concentrations were examined in each group. &#x0D; Results: The results showed a significant decrease in oocyte, fertilization percentage, 2, 4 and 8 cell, Compact and blastocytes embryos in the acrylamide group compared to the control (P&lt;0.05). In acrylamide group, MDA concentration increased and TAC showed a significant decrease compared to other groups (P&lt;0.05). There was a significant increase in oocyte count and fertilization percentage in taurine group compared to the control (P‌&lt;0.001). A significant increase in the above parameters was observed in the acrylamide + taurine group at a dose of 150 mg / kg compared to the acrylamide group (P&lt;0.05). Percentage of fertilization and embryos of 2, 4 and 8 cells, Compact and blastocytes in the curcumin group showed a significant decrease compared to the control (P&lt;0.05).&#x0D; Conclusion: The results indicate that taurine has a better performance in reducing the side effects of acrylamide than curcumin. Since curcumin can prevent IVF, it should be used with more caution at the beginning of pregnancy.

Protective effect of resveratrol against cadmium-induced toxicity on ovine oocyte in vitro maturation and fertilization

BackgroundHeavy metal cadmium (Cd) is a widespread environmental contaminant with a potential toxicity that might negatively affect female reproduction and fertility. It has been reported that Cd exposure impaired the quality of oocytes and led to a defective maturation and fertilization, through oxidative stress induction. Resveratrol (Res) is a natural polyphenol with strong antioxidant properties that exhibited protective role in preventing oocyte redox homeostasis disruption and quality decline. Here, we explored whether the addition of Res to in vitro maturation (IVM) medium might act as a protection against Cd-induced toxicity on ovine oocyte maturation and fertilization. Firstly, we evaluated the effect of supplementing IVM medium with two different Res concentrations (1 and 2 μmol/L) on nuclear maturation and fertilization of oocytes matured under CdCl2 (2 μmol/L) exposure. Therefore, the concentration of 1 μmol/L Res was selected to analyse the effects of this compound on intracellular ROS levels, mitochondrial (mt) distribution and activity, chromatin configuration, cytoskeleton morphology, cortical granules (CGs) distribution and mRNA expression of genes associated with cellular response to oxidative stress (i.e. SIRT1, SOD 1, GPX1, GSR, CAT) in Cd-exposed in vitro matured oocytes.ResultsWe found that 1 μmol/L Res restored the reduced oocyte meiotic competence induced by Cd exposure as well as, Res sustained oocyte ability to be normally fertilized and decreased polyspermic fertilization at both tested concentrations. Moreover, we demonstrated that 1 μmol/L Res mitigated Cd-induced alterations of oocyte cytoplasmic maturation by reducing reactive oxygen species (ROS) accumulation, preventing mt dysfunction, maintaining the correct meiotic spindle and cortical F-actin assembly and the normal cortical granule distribution as well as up-regulating SIRT1, SOD1 and GPX1 genes.ConclusionsTaken together, our findings highlighted the beneficial influence exerted by Res in preventing Cd-induced disturbance of nuclear and cytoplasmic maturation and subsequent fertilization in ovine oocytes. Res treatment may help to establish defence strategies counteracting Cd-induced toxicity on the female gamete.

Effect Analysis of Degranulated Cell in Early Fertilization on FET Outcome and Offspring Safety with Data Mining.

In vitro fertilization and embryo transfer is one type of assisted reproductive technology, although the technology is now more mature. Many factors, however, will have an impact on oocyte fertilization, embryo growth, pregnancy outcome, and child safety due to the journey from clinical to the laboratory. The influence of degranulated cells early in fertilization on frozen embryo transfer (FET) results is investigated in this study. This article analyzes 255 patients who underwent in vitro fertilization (IVF) and FET transplantation at the author's central unit from January 1, 2015, to June 30, 2021. Among them, IVF-assisted conception is the early degranulation of homologous oocyte fertilization. Correlation analysis is performed by observing the embryonic outcome of the early degranulation group and the overnight fertilization group and the clinical outcome after FET. Through data mining analysis, the results show that the polyfertilization rate and 0PN rate for the early degranulation group are significantly higher than the overnight fertilization group (9.87% vs. 8.24% and 3.14% vs. 1.69%). In terms of normal fertilization rate, there is no significant difference between D3 high-quality embryo rate and D5 high-quality blastocyst rate (64.07% vs. 65.15%, 27.5% vs. 26.5%, and 15.97% vs. 17.35%). There is no significant difference in the complete recovery rate of embryos after thawing (93.24% vs. 93.46%), and the implantation rate, clinical pregnancy rate, abortion rate, and live birth rate are not significantly different between the two groups after FET. The offspring outcomes of singletons do not differ significantly between the two groups; however, twins born early degranulate have much greater rates of ultralow birth weight and ultrapreterm children than twins born overnight fertilization (14.29% vs. 0). Therefore, it can be concluded that degranulation of cells early in fertilization is a desirable method to prevent fertilization disorders. However, under the premise of ensuring that no fertilization disorder occurs, it is not appropriate to degranulate all the oocytes of the patient at the early stage of fertilization.

Follicular fluid steroid hormones and in vitro embryo development in Duroc and Landrace pigs

The Duroc sire line has a smaller litter size compared to the Landrace dam line and we have previously observed fewer surface follicles on Duroc ovaries one day after weaning. In that same study, a broader cumulus expansion and faster nuclear maturation were observed for Duroc oocytes at 20 h of in vitro maturation (IVM), while Landrace oocytes showed more advanced stages of cortical granule distributions. However, no differences between breeds were observed after the final IVM period. The aim of this study was to assess subsequent in vitro embryo production (IVP) in Duroc and Landrace. Furthermore, follicle diameter and steroid hormone levels in follicular fluid (FF) were measured to study possible relation to oocyte developmental competence. Follicular phase sow ovaries were collected one day after weaning and follicle size of the 10 largest follicles were measured per ovary before aspiration. Cumulus-oocyte complexes (COCs) were matured in vitro, and cumulus expansion was analysed by assessing individual COC areas at 0 and 20 h. Fertilization of Duroc and Landrace oocytes was performed with sperm from both a Duroc and a Landrace boar. A larger follicle diameter was observed for Landrace animals (5.7 vs. 4.8 mm, P < 0.0001) and individual COC area was additionally larger at 0 h after aspiration (P < 0.0001) compared to Duroc. Contrary, cumulus expansion from 0 to 20 h of maturation was broader for Duroc oocytes than for Landrace (407 ± 67% vs. 319 ± 31%, P < 0.0001). After fertilization, cleavage rate was higher for Duroc oocytes, and the highest blastocyst yield was obtained for Duroc oocytes fertilized with the Landrace sperm. Steroid hormone analysis of the follicular fluid showed differences in the pathways between breeds with a higher total level of estrogens (P = 0.01) and aromatase products/substrates ratio (P < 0.01) in Landrace compared to Duroc. In conclusion, results suggest that Duroc oocytes have a better in vitro oocyte developmental competence when cultured under the same in vitro conditions and breed differences in steroidogenesis were found in the early follicular phase.

Follicular Hyperstimulation Dysgenesis: New Explanation for Adverse Effects of Excessive FSH in Ovarian Stimulation.

High follicle-stimulating hormone (FSH) doses during ovarian stimulation protocols for assisted reproductive technologies (ART) are detrimental to ovulatory follicle function and oocyte quality. However, the mechanisms are unclear. In a small ovarian reserve heifer model, excessive FSH doses lead to phenotypic heterogeneity of ovulatory size follicles, with most follicles displaying signs of premature luteinization and a range in severity of abnormalities. By performing whole transcriptome analyses of granulosa cells, cumulus cells, and oocytes from individual follicles of animals given standard or excessive FSH doses, we identified progressive changes in the transcriptomes of the 3 cell types, with increasing severity of follicular abnormality with the excessive doses. The granulosa and cumulus cells each diverged progressively from their normal phenotypes and became highly similar to each other in the more severely affected follicles. Pathway analysis indicates a possible dysregulation of the final stages of folliculogenesis, with processes characteristic of ovulation and luteinization occurring concurrently rather than sequentially in the most severely affected follicles. These changes were associated with disruptions in key pathways in granulosa and cumulus cells, which may account for previously reported reduced estradiol production, enhanced progesterone and oxytocin production and diminished ovulation rates. Predicted deficiencies in oocyte survival, stress response, and fertilization suggest likely reductions in oocyte health, which could further compromise oocyte quality and ART outcomes.

Lysophosphatidic Acid Improves Human Sperm Motility by Enhancing Glycolysis and Activating L-Type Calcium Channels.

Until now, the molecular mechanisms underlining sperm motility defect causing male infertility are still poorly understood. Safe and effective compounds or drugs that can improve sperm motility are also very limited. Lysophosphatidic acid (LPA) is a naturally occurring phospholipid and a bioactive intermediate with multiple biological activities. It has been detected in various body fluids such as serum, plasma, saliva, tears, blister fluids, hen egg white, and ascites from patients with ovarian cancer. LPA is also abundant in seminal plasma and follicular fluid. It enhances follicle stimulation, improves oocyte fertilization, and promotes early embryonic development and embryo implantation. However, the physiological role of LPA in the male reproductive system remains unknown. Here, our study showed that LPA significantly improved the motility parameters of human sperm hyperactivation in a dose-dependent manner. The LPA-induced elevation of sperm motility is dependent on bovine serum albumin (BSA) but independent of the classical BSA-induced sAC/cAMP/PKA signaling pathway. The enhancement of sperm motility by LPA could not be blocked by CCCP, a respiratory inhibitor suppressing mitochondrial ATP production. Moreover, LPA improved the activity of triosephosphate isomerase in glycolysis. Meanwhile, LPA treatment significantly increased ATP and phosphoenolpyruvate levels and decreased ADP content during sperm glycolysis. Notably, none of known or identified LPA receptors was detected in human sperm. Further investigations showed that LPA promoted sperm motility through L-type calcium channels. In summary, this study revealed the involvement of LPA in the regulation for human sperm motility by enhancing glycolysis and activating L-type calcium channels. The current findings may shed new light on the understanding of causes of asthenozoospermia, and indicate that LPA could be used as a novel therapeutic agent to improve sperm function and fertilizing capacity.

Higher quality rather than superior quantity of oocytes determine the amount of fertilizable oocytes in two outbred Dummerstorf high‐fertility mouse lines

Dummerstorf fertility lines FL1 and FL2 represent two models of enhanced fertility characterized by the doubling of the litter size compared with an unselected control population (ctrl line, Dummerstorf FztDU). Both biodiverse FLs managed to reach this goal by increasing the ovulation rate per cycle, even showing decreased pregnancy rate and irregular oestrous cycle and metabolic hormone levels, compared with ctrl. The aim of the present study was to analyse oocytes in terms of quality and quantity by comparing the entire pool of oocytes per ovary, with those from the antral follicles within the same animal. We performed Brilliant Cresyl Blue staining as a non-invasive marker of oocyte quality in combination with an analysis of additional morphological indicators, e.g. cytoplasm clarity, cumulus cell layers, nuclear anatomy, size and shape. We compared our fertility lines with the unselected control population and with another independent line selected from the same founder population, showing lower litter size (DU6P). Our results suggest that fertility lines show decreased number of oocytes per ovary compared with DU6P but increased number of high-quality oocytes before ovulation. Hence, the raise in the ovulation rate and litter size of those super fertile mouse lines are not associated with an increased number of oocytes per ovary but rather with an increased number of higher quality fertilizable oocytes per cycle. In addition, the most conspicuous method to acquire oocytes with the highest quality in our lines is to assess their morphology, rather than their status after staining. All these discoveries together may be of fundamental importance for further studies in livestock farm animals showing some similar characteristics, e.g. irregular cycle or hormonal misbalances, to improve production while lowering costs, and in humans to increase the possibilities of successful pregnancies for couples undergoing in vitro fertilization (IVF).

Epigenetic Alterations in Cryopreserved Human Spermatozoa: Suspected Potential Functional Defects.

Background: Gene set enrichment analysis (GSEA) was conducted on raw data, and alternative splicing (AS) events were found after mRNA sequencing of human spermatozoa. In this study, we aimed to compare unknown micro-epigenetics alternations in fresh and cryopreserved spermatozoa to evaluate the effectivity of cryopreservation protocols. Methods: Spermatozoa were divided into three groups: fresh spermatozoa (group 1), cryoprotectant-free vitrified spermatozoa (group 2), and conventionally frozen spermatozoa (group 3). Nine RNA samples (three replicates in each group) were detected and were used for library preparation with an Illumina compatible kit and sequencing by the Illumina platform. Results: Three Gene Ontology (GO) terms were found to be enriched in vitrified spermatozoa compared with fresh spermatozoa: mitochondrial tRNA aminoacylation, ATP-dependent microtubule motor activity, and male meiotic nuclear division. In alternative splicing analysis, a number of unknown AS events were found, including functional gene exon skipping (SE), alternative 5′ splice sites (A5SS), alternative 3′ splice sites (A3SS), mutually exclusive exon (MXE), and retained intron (RI). Conclusions: Cryopreservation of spermatozoa from some patients can agitate epigenetic instability, including increased alternative splicing events and changes in crucial mitochondrial functional activities. For fertilization of oocytes, for such patients, it is recommended to use fresh spermatozoa whenever possible; cryopreservation of sperm is recommended to be used only in uncontested situations.

Iron-overloaded follicular fluid increases the risk of endometriosis-related infertility by triggering granulosa cell ferroptosis and oocyte dysmaturity

Endometriosis (EMs) occurs in approximately 50% of women with infertility. The main causes of EMs-related infertility are follicle dysplasia and reduced oocyte quality. Iron overload occurs in ovarian follicular fluid (FF) of patients with EMs, and this condition is associated with oocyte maturation disorder. However, the underlying molecular mechanism remains largely unknown. In the present study, we identified the mechanism underlying ferroptosis in ovarian granulosa cells and oocyte maturation failure in EMs based on a retrospective review of in vitro fertilization/intracytoplasmic sperm injection-frozen embryo transfer outcomes in infertile patients with EMs. Mouse granulosa cells were treated with EMs-related infertile patients' follicular fluid (EMFF) in vitro. Western blot analysis, quantitative polymerase chain reaction, fluorescence staining, and transmission electron microscopy were used to assess granulosa cells ferroptosis. The effects of exosomes were examined by nanoparticle tracking analysis, RNA-seq, and Western blot analysis. Finally, the therapeutic values of vitamin E and iron chelator (deferoxamine mesylate) in vivo were evaluated in an EMs-related infertility model. Patients with ovarian EMs experienced poorer oocyte fertility than patients with non-ovarian EMs. We observed that EMFF with iron overload-induced granulosa cell ferroptosis in vitro and in vivo. Mechanically, nuclear receptor coactivator four-dependent ferritinophagy was involved in this process. Notably, granulosa cells undergoing ferroptosis further suppressed oocyte maturation by releasing exosomes from granulosa cells. In therapeutic studies, vitamin E and iron chelators effectively alleviated EMs-related infertility models. Our study indicates a novel mechanism through which EMFF with iron overload induces ferroptosis of granulosa cells and oocyte dysmaturity in EMs-related infertility, providing a potential therapeutic strategy for EMs-related infertility.

P-148 Denudation employing human recombinant hyaluronidase enzyme does not affect fertilization and blastocyst formation rates in sibling oocytes from patients undergoing ART: A prospective randomized study

Abstract Study question Does human recombinant hyaluronidase (Cumulase®) improve fertilization and blastocyst formation rates in sibling human oocytes compared to bovine-derived hyaluronidase? Summary answer The use of Cumulase® for oocyte denudation does not appear to affect fertilization or usable blastocyst formation rate in patients undergoing intracytoplasmic sperm injection (ICSI). What is known already Bovine-derived hyaluronidase has been widely employed to denude the cumulus-oocyte complexes (COCs) prior to ICSI or oocyte vitrification. Nonetheless, the recent concern for its safety, due to its animal origin, has led to the development of alternatives ascertaining the enzyme’s purity. It has been reported that human recombinant hyaluronidase is not equally effective as its bovine-derived analogue, leading to a longer time required for complete denudation coupled by the subsequent toxicity risk for oocytes. This may result to lower fertilization and blastocyst formation rates. Although there are some studies on IVF outcomes with recombinant hyaluronidase, its use remains rather limited. Study design, size, duration This randomized double-blinded clinical trial was conducted at Citmer Reproductive Medicine, in Puebla and Monterrey, Mexico from February to December 2021. The impact of denudation on sibling oocytes from 103 patients employing bovine-derived hyaluronidase (InVitroCare®) or human recombinant hyaluronidase (ICSI Cumulase® (rHuPH20), CooperSurgical®) was evaluated. A total of 1237 oocytes were assigned as follows: The Hyaluronidase Group included 626 oocytes, while the Cumulase® Group included 611 oocytes. Preimplantation Genetic Testing was performed in 18 cycles. Participants/materials, setting, methods After retrieval, COCs were incubated for 2-4 h and placed in microdropets with 10 IU/mL bovine-derived hyaluronidase or Cumulase® in culture media GlobalTotal® (LifeGlobal®) for granulosa cells removal. COCs were gently pipetted up and down employing 20 μL and 150 μm tips. Metaphase II oocytes were injected and incubated for 17-20 hours in 8% CO2, 20% O2, 37°C. Normally fertilized zygotes were cultured to blastocyst stage and embryo development was evaluated. Seventy-nine blastocysts were biopsied. Main results and the role of chance The mean age of the patients was 32.12±1.11 years old. A total of 506 and 493 metaphase II oocytes from Groups 1 and 2 respectively were subjected to ICSI. Normal fertilization rates for oocytes treated with Hyaluronidase and Cumulase® were 71.34% (n = 361) and 72.41% (n = 357) respectively, with no statistically significant differences between the two groups (p = 0.35). Usable blastocysts rate (selected for embryo transfer or blastocyst cryopreservation) did not differ with any statistical difference between the bovine-derived hyaluronidase (n = 170, 47.09%) and the Cumulase® treated oocytes (n = 158, 44.25%), (p = 0.44). Preimplantation genetic testing for aneuploidies (PGT-A) was performed in 18 cycles. Seventy-nine blastocysts were biopsied and tested. Fourty-seven embryos from the bovine-derived hyaluronidase group were biopsied, presenting with a euploidy rate of 51.06% (n = 24), compared to 32 embryos from the recombinant hyaluronidase group with a euploidy rate of 50% (n = 16). Results indicated no statistically significant difference (p = 0.92). These data support that human recombinant hyaluronidase presents with similar efficacy to bovine-derived hyaluronidase. in terms of normal fertilization, embryo development as well as euploidy rates. Limitations, reasons for caution The small sample size regarding the euploidy outcome stands as a limitation of the study. Further studies should focus on the effect of recombinant hyaluronidase on genetic anomalies on blastocysts. Wider implications of the findings Fertilization, usable blastocyst and euploidy rates did not differ when employing bovine-derived or human recombinant hyaluronidase, rendering the latter a safe and efficient alternative. However, it is important to assess long-term effects, as only a limited number of studies report on perinatal and neonatal outcomes Trial registration number 25-12-21MTYPUECIT

P-677 Increasing the efficacy of FSH with a potentiating monoclonal antibody

Abstract Study question Can we potentiate FSH activity with antibodies to improve ovarian stimulation? Summary answer IGYXOS developed a potentiating monoclonal antibody that improves FSH potency and efficacy in vitro and in vivo as demonstrated in different animal models. What is known already FSH plays a key role in reproduction. For a controlled ovarian stimulation in IVF cycles, FSH-containing preparations are injected to patients in order to obtain mature and fertilizable oocytes. However, the efficacy of these treatments is frequently limited and sometimes several attempts are needed before reaching a pregnancy and a live birth. It was previously demonstrated that breeding animals treated with gonadotropins could develop anti-gonadotropin antibodies that enhance their bioactivity instead of inhibiting it. These females had a high kidding rate and sometimes were hyperprolific. Study design, size, duration IGYXOS developed a monoclonal antibody (mAb) directed against human FSH. The mAb CF12 was selected based on its ability to increase FSH activity in vitro and in vivo in female rat. Its potentiating activity was tested on different human FSH preparations. The potentiating effect of CF12 was further investigated in ewe treated with mAb alone or FSH alone. Participants/materials, setting, methods CF12 was tested in vitro on HEK 293 cells expressing the human FSH receptor and a cell reporter system for cAMP. In vivo, the mAb was tested according to the Steelman and Pohley protocol on different human FSH preparations. Its potentiating effect was also investigated in an ovulation induction protocol on mature ewes. Main results and the role of chance In HEK 293 cells expressing the human FSH receptor, CF12 combined to FSH improved both the potency (EC50) and the efficacy (Emax) of FSH by increasing the cyclic AMP production at all tested FSH concentrations. The potentiating activity was confirmed in immature female rats treated with hCG+FSH alone or combined to mAb, twice a day, during 3 days. The animals were sacrificed the fourth day of treatment and the weight of the ovaries was compared. Ovaries weight was significantly increased in the group treated with hCG/FSH+CF12 compared to hCG/FSH only. To further analyze the effect of CF12 on ovulation induction, it was investigated in ewe as a breeding animal model. Animals were first synchronized with a progestagen and then treated either with FSH alone or with CF12 alone. The number of ovulations was investigated by endoscopy by counting corpora lutea and the progesterone secretion was measured over the luteal cycle. All females treated with CF12 ovulated (100%) by contrast 40% ovulated with FSH treatment. The ovulation rate was 1.8 fold higher in group treated with CF12 compared to FSH group. Moreover, progesterone secretion during luteal phase was increased in animals treated with CF12 suggesting a better quality of corpora lutea. Limitations, reasons for caution After several proofs of concept obtained in different animal models, the compound is currently in the humanization phase before starting the CMC process and then preclinical studies. Wider implications of the findings The potentiating antibody CF12 is a new concept. It represents an interesting strategy in reproductive health, particularly to improve the IVF outcome. CF12 is currently developed for human application by our company and could be a game changer in the field of ovarian stimulation by enhancing the efficacy of FSH. Trial registration number not applicable

P-188 The effect of follicular fluid extracellular vesicles on motility and hyperactivation of human spermatozoa and differential miRNA levels depend on the woman's age

Abstract Study question How does the woman’s reproductive age affect the ability of follicular fluid (FF) extracellular vesicles (EV) to change the motility and hyperactivation of spermatozoa and follicular fluid microRNA profiles? Summary answer The effect of FF EVs on sperm motility and hyperactivation decreases with a woman's age. MiR-134-5p, miR-21-5p expression levels increase in older age group. What is known already Aging reduces human fertility. FF is an important factor in attracting and activating spermatozoa in the oviduct during oocyte fertilization, enhancing the process of sperm capacitation and acrosomal reaction in various mammalian species, including humans. EVs from seminal plasma and oviduct fluid carry proteins and miRNAs playing a vital role in a multi-step process including sperm motility, capacitation, acrosomal reaction, further fertilization. Results of our previous experiments showed that FF EVs from young women significantly improve the indices of sperm motility and hyperactivation. Several studies have isolated some age associated differentially expressed miRNAs (hsa-miR-424, hsa-miR-21-5p, hsa-miR-134, hsa-miR-190b, hsa-miR-99b -3p). Study design, size, duration FF EVs were obtained by sequential centrifugation at different rotational speeds, frozen at -80 °C. The sperm fraction was isolated, washed by differential centrifugation in a density gradient, suspended in the saline to a concentration of 106/ml and incubated with EVs (1:2) at 37 °C in CO2-incubator for 1 h. Samples were centrifuged and fixed in 2.5% glutaraldehyde in 0.1 M buffer for TEM. Sperm motility were assessed using CASA. MicroRNAs isolation (miRNeasy Serum/Plasma Kit (Qiagen)). Participants/materials, setting, methods All study participants signed a voluntary informed consent for the use of biological samples for research purposes. Sperm samples were isolated from seminal fluid (n = 18) aged 28-36 years without severe pathozoospermia. FF EVs were obtained from young (n = 4) aged 27-31 (EVs+) and older patients (n = 4) aged 41-46 with several IVF attempts (EVs-). The methods used in this work include sperm and EVs isolation, incubation, transmission electron microscopy, RT-PCR, statistical data analysis, computer-assisted semen analysis (CASA). Main results and the role of chance Our results showed that sperm incubation with EVs+ led to a significant increase in the number of progressively motile spermatozoa (paired Student's t test, p &amp;lt; 0.001), indicators of general mobility (p = 0.05) and hyperactivation of spermatozoa after 1 hour. Sperm incubation with EVs- slightly changed these parameters compared to the control (p = 0.171). Results from TEM showed that EVs- bind to spermatozoa worse than EVs+ after incubation. EVs- bind predominantly to the lateral membrane of the spermatozoon, rather than to the acrosomal region, compare to EVs+, which may reflect changes in the functional composition of FF EVs in older patients group and target areas of interaction with spermatozoa. This hypothesis is also supported by slight improvements in progressive sperm motility after incubation. Age-related changes are reflected in energy, metabolic and other important biological processes, which leads to a change in the composition and functions of FF (decrease in progesterone, glucose, increase in lactate and pyruvate, increase in reactive oxygen species) and affect the functional role of FF EVs. MiR-134-5p (p = 0.008), miR-21-5p (p = 0.008) expression levels were statistically significantly higher in EVs- group compared with EV + group with a successful first attempt. The expression of other microRNAs analyzed did not differ between groups. Limitations, reasons for caution Small amount of data. This study does not characterize isolated FF EVs in any way (specific markers, EVs concentration, size). To discuss the possible mechanisms underlying the effects of FF EVs of different age groups on sperm characteristics, it is necessary to perform metabolomics analyses of FF EVs. Wider implications of the findings Further studies of the influence of FF EVs on sperm motility may help to improve of ART outcomes, associated with male and female infertility by improving sperm morphofunctional characteristics and increasing their fertilizing ability. The solutions to this problem could be the use of FF EVs from young fertile donors. Trial registration number not applicable

P-155 Follicular fluid antibodies associated with quality of oocytes and fertilization rate in IVF-ICSI cycles

Abstract Study question Which follicular fluid (FF) autoantibodies influence oocyte quality and its fertilization potential in the settings of IVF-ICSI? Summary answer The measured follicular fluid levels of anti-thyroperoxidase and anti-aromatase antibodies are associated with lower number of mature oocytes and fertilization rate in IVF-ICSI cycles. What is known already Nowadays it is known that there is clear correlation between serum and follicular fluid antibody levels indicating their ability to pass freely through blood-follicle barrier. It is believed that anti-thyroid antibodies may exert direct toxic effect on the growing follicle and adversely affect the quality of future embryo due to the direct interaction with zona pellucida antigens, disordering its functional role and, consequently, altering oocyte fertilization and developmental potential. However, at this point no cases of anti-aromatase antibody detection in the follicular fluid of women undergoing fertility treatment have been reported. Study design, size, duration A prospective cohort study including 90 patients undergoing IVF-ICSI was performed at the Department of ART, The D. O. Ott Research Institute of Obstetrics and Gynecology from September 2018 to March 2020. During oocyte retrieval only the first aspiration including cumulus-oocyte complexes (COC) were used for the study. After COC removal, the pre-ovulatory FF was centrifuged at 2000×g for 10 min. The cell-free supernatants were divided into aliquots and stored at 80 oC until assay. Participants/materials, setting, methods FF investigation included anti-thyroperoxidase (AT-ТРО, BlueGene, Сhina, E01T0531) and anti-aromatase (anti-ARO, Cloud-Clone Corp., USA, AEC319Hu) antibodies detection using commercial ELISA kits. The threshold value for each antibody was calculated as 3*SD from the mean values of patients investigated. Thus, the study group included 52 women with FF autoantibodies ≥ (M + 3*SD) (if at least one marker positive), the comparison group comprised 38 women with FF autoantibodies &amp;lt; (M + 3*SD). Main results and the role of chance In the study group, the number of mature oocytes was notably lower than in the comparison group (6.5 (3.5; 9.5) vs 9 (8; 11); P &amp;lt; 0,01). A significant inverse correlation between follicular fluid AT-TPO (rs =-0.5; P &amp;lt; 0.05) and anti-ARO (rs =-0.5; P &amp;lt; 0.05) antibody levels and the number of mature oocytes was revealed in all investigated samples. In addition, despite no difference in the rate of mature oocytes between the groups (84% vs 88%, P &amp;gt; 0.05) it negatively correlated with anti-ARO FF (rs =-0.4; P &amp;lt; 0.05) among all the participants. Evaluation of oocyte fertilization rate using a linear regression analysis showed its significant dependence on the follicular fluid anti-aromatase antibody levels (R = 0,33; P &amp;lt; 0,01). Limitations, reasons for caution Small sample size Wider implications of the findings Further studies with larger sample size evaluating anti-ARO antibodies are needed in order to understand its origin and effect on early steps of human reproduction. Trial registration number not applicable