Morphological selection of gametes

Three Novel Mutations in TUBB8 Cause Female Infertility Due to Multiple Morphological Abnormalities of the Oocyte and Early Embryo

Recent years have seen a global increase in infertility, affecting up to 17.5% of the population. For successful human reproduction, the proper development process of the oocyte, fertilization, and early embryo is required. Assisted reproductive technology (ART), which is the primary treatment for infertility, uses the morphology of oocytes and zygotes as parameters to predict ART outcomes. However, factors such as large perivitelline space (PVS), centrally located granular cytoplasm (CLGC), multi-pronuclei (MPN) formation, and final early embryonic development arrest often lead to repeated failure of ART treatment. Genetic analysis has identified various pathogenic genetic factors contributing to infertility, suggesting that genetic variation plays a significant role in recurrent ART treatment failure. However, maternal genes responsible for large PVS, CLGC, and MPN formation are rarely reported. In this study involving Whole Exome Sequencing (WES) and Sanger sequencing validation, three novel heterozygous missense mutations (p.M403V, p.R306H, p.H190Y) in TUBB8 were identified as being associated with large PVS, CLGC, MPN formation, and early embryonic development arrest. These mutant sites are evolutionarily conserved in different species. Additionally, in silico and in vitro experiments demonstrate that these variants disrupt the conformation, expression, and microtubule structures of the TUBB8 protein. Therefore, these findings contribute significantly to understanding TUBB8-related large PVS, CLGC, and MPN formation in the context of ARTs. This broadens our insight into the genetic connection in human reproduction and emphasizes the importance of comprehensive genetic screening and personalized intervention strategies for PVS, CLGC, and MPN formation.

Activation of Proteolysis During Oocyte In Vitro Maturation

In vitro maturation (IVM) is a form of assisted reproductive technology (ART) applied to obtain mature oocytes in culture. Decline in IVM success rates by age has led consideration of novel approaches based on cellular dynamics. Our aim was to achieve proteostasis in old bovine oocytes from 13 to 16-year-old bovine with a lower potential for fertilization. Lysosomal activation was achieved through increasing concentrations of proton pump activators PIP2 (0.1, 0.5, 1, and 5 μM), PMA (0.1, 1, 10, and 50 μM), and DOG (0.1, 1, 10, and 50 μM) at 6, 12, 18, and 24 h of IVM in old bovine oocytes. Morphological analysis was performed and IVM rates were determined. DQ-Red BSA was applied to live oocytes to determine proteolytic activation while lysosome density was determined by Lysotracker probe. Protein carbonylation was detected through oxyblot analysis. Polar body extrusion (PBE), through which a haploid nonfunctional polar body is released in the perivitelline space after completion of the first meiotic division, was observed in PIP2-0.1 μM, -0.5μM-6h; PIP2-5μM-12h; PMA-0.1μM-18h; PIP2-0.1μM, -0.5μM-24h groups. Oocyte diameter was the highest in DOG-1μM-6h, PMA-0.1μM-12h, PIP2-1μM-18h, and PIP2-0.5μM-24h groups. Morphological scores of oocytes were higher in young and old control groups. PIP2, PMA, and DOG affected oocyte quality positively after 6 h of IVM yielding in oocyte scores similar to the control group oocytes. However, they had a negative impact on the oocyte scores in longer periods of IVM, except for lower doses PMA (0.1 and 1 μM) at 12 h and PIP2 (0.5 μM) and PMA (0.1 μM) at 18 h, which were able to maintain the scores relatively closer to the control oocytes. Proteolytic activation was achieved in all groups at 6 h of culture. At all other time points PIP2 and PMA groups showed a better response to proteolytic activation. Lysosome density was increased in PIP2-5μM-6h; PIP2-0.1μM, -1μM-12h; PIP2-1μM, -5μM-18h as well as PMA-0.1μM-6h; PMA-1μM, -10μM-12h; PMA-1μM-18h; DOG-50μM-6h and DOG-0.1μM-12h. Protein carbonylation was the lowest in PIP2-0.1 μM groups at 12, 18, and 24 h. This study suggests that proton pump activators PIP2 and PMA was found to have a positive impact on IVM in terms of both morphological scores and proteolytic activation in a time and dose dependant manner.

Applying an evolutionary perspective to assisted reproductive technologies

Assisted reproductive technologies (ART) are commonly used to address human infertility and to boost livestock production. During ART, procedures such as in vitro fertilization, artificial insemination, and intracytoplasmic sperm injection introduce gametes and embryos to unnatural and potentially stressful conditions that can influence offspring health, often via epigenetic effects. In this perspective we summarize these key risks of ART for embryonic and longer-term offspring fitness, emphasizing the need for experimental research on animal models to determine causal links between ART and offspring fitness across multiple generations. We also highlight how ART can bypass a range of naturally and sexually selected mechanisms that occur in the female reproductive tract and/or via female secretions that ultimately determine which sperm fertilize their eggs. We further argue that this curtailment of female-modulated mechanisms of sperm selection may have important consequences for ART-conceived offspring. We encourage the development of ART methods that better mimic natural processes of sperm selection and embrace the fundamental principles of natural and sexual selection. Ultimately, the aim of this perspective is to encourage dialogue between the fields of evolutionary biology and applied areas of animal and human reproduction.

Supplementation of SkQ1 Increases Mouse In Vitro Oocyte Maturation and Subsequent Embryonic Development by Reducing Oxidative Stress

In vitro oocyte maturation (IVM) technology is important for assisted animal and human reproduction. However, the maturation rates and developmental potential of in vitro-matured oocytes are usually lower than those of in vivo-matured oocytes. Oxidative stress is a main factor that causes the lower maturation rates and quality of in vitro-matured oocytes. The purpose of this study was to investigate the effects of treatment with SkQ1, a mitochondria-targeted antioxidant, on mouse IVM and subsequent embryonic development. The results demonstrated that the supplementation of SkQ1 during IVM improves the maturation rates of mouse oocytes and the subsequent developmental competence of in vitro-fertilized embryos. The addition of SkQ1 to the IVM medium also decreased oxidative stress and apoptosis, and increased mitochondrial membrane potential in matured mouse oocytes. This study provides a new method through which to enhance the maturation rates and the quality of in vitro-matured mouse oocytes, thus promoting the application and development of assisted animal and human reproductive technology.

Effects of myo-inositol plus folic acid on ovarian morphology and oocyte quality in PCOS mouse model

Although the role of myo-inositol (MYO) in promoting the oocyte quality of PCOS patients has been documented in human studies; the cellular effects of this supplement on oocytes have not been directly examined due to ethical limitations. In the first phase of this study, MYO dosimetry was carried out simultaneously with the PCOS model development. An effective dose was obtained following the assessment of fasting insulin and testosterone levels using ELISA and ovarian morphology appraisal by histopathology. In the second phase, following the continuous administration of the effective dose of MYO and dehydroepiandrosterone (DHEA), cellular evaluation was performed. The quality of oocytes from superovulation was analyzed by examining maturity and normal morphology percentage using a stereomicroscope, intracellular reactive oxygen species (ROS) and glutathione (GSH) levels using fluorometry, and ATP count evaluation using ELISA. The results revealed that, among the four different MYO concentrations, the 0.36 mg/g dose compared with the DHEA group reduced testosterone levels and large atretic antral follicles (LAtAnF) diameter. This dose also increased the corpus luteum count and the granulosa:theca (G/T)layer thickness ratio in antral follicles. Furthermore, this dose increased mature oocytes and normal morphology percentage, ATP count, and GSH levels; however, it decreased ROS levels in mature oocytes. Our findings provide the grounds for further cellular and molecular studies on the PCOS mouse model, suggesting that the improvement in mitochondrial function and its antioxidant properties is probably one of the mechanisms by which MYO increases oocyte quality.

Evaluation of Intrafollicular Syndecan 1, Glypican 3, and Spermidine Levels in Women with Diminished Ovarian Reserve

We aimed to evaluate the levels of Spermidine, Syndecan 1, and Glypican 3 (GPC3) in the follicle fluid of women with diminished ovarian reserve (DOR) and to examine the relationship of these markers with the number of embryos and clinical pregnancy. A total of 27 women with DOR and 34 women with normal ovarian reserve who underwent in vitro fertilization procedure were included in this prospectively designed study. Spermidine, Syndecan 1, and GPC3 levels were studied in the follicle fluid samples taken from the women at the time of oocyte retrieval by ELISA method, and their relations with the cycle outcomes were examined. The mean age was found as 38.1 ± 7.4 years in the DOR group and 35.1 ± 5.2 years in the control group (p = 0.027). When adjusted for age and body mass index, while the median Spermidine level was significantly higher (p < 0.001), both Syndecan 1 (p < 0.001) and GPC3 (p = 0.006) were significantly lower in the DOR group compared with control group. The cut-off value of Spermidine for clinical pregnancy prediction was found as 74.08 ng/mL with 78.9% sensitivity and 57.1% specificity [OR: 5 (95% CI: 1.4-17.6); AUC: 0.621; p = 0.138], while it was 0.96 ng/mL with 84.2% sensitivity and 59.5% specificity [OR: 7.8 (95% CI: 2-31.1); AUC: 0.701; p = 0.004] for GP3 and 1.15 ng/mL with 78.9 sensitivity and 57.1% specificity [OR: 5 (95% CI: 1.4-17.6); AUC: 0.680; p = 0.009] for Syndecan 1. Intrafollicular spermidine, Syndecan 1, and GPC3 levels may have a role in ovarian aging. Further randomized controlled studies in a larger population are needed for the relationship of these markers with cycle and pregnancy outcomes.

Assisted Reproductive Technology without Embryo Discarding or Freezing in Women ≥40 Years: A 5-Year Retrospective Study at a Single Center in Italy

The protocols commonly used in assisted reproductive technology (ART) consist of long-term embryo culture up to the blastocyst stage after the insemination of all mature oocytes, the freezing of all the embryos produced, and their subsequent transfer one by one. These practices, along with preimplantation genetic testing, although developed to improve the live birth rate (LBR) and reduce the risk of multiple pregnancies, are drawing attention to the possible increase in obstetric and perinatal risks, and adverse epigenetic consequences in offspring. Furthermore, ethical-legal concerns are growing regarding the increase in cryopreservation and storage of frozen embryos. In an attempt to reduce the risk associated with prolonged embryo culture and avoid embryo storage, we have chosen to inseminate a limited number of oocytes not exceeding the number of embryos to be transferred, after two days or less of culture. We retrospectively analyzed 245 ICSI cycles performed in 184 infertile couples with a female partner aged ≥40 from January 2016 to July 2021. The results showed a fertilization rate of 95.7%, a miscarriage rate of 48.9%, and a LBR of 10% with twin pregnancies of 16.7%. The cumulative LBR in our group of couples was 13%. No embryos were frozen. In conclusion, these results suggest that oocyte selection and embryo transfer at the cleaving stage constitute a practice that has a LBR comparable to that of the more commonly used protocols in older women who have reduced ovarian reserve.

Profiling of mitochondrial heteroplasmy in single human oocytes by next-generation sequencing

Mitochondrial DNA (mtDNA) plays a crucial role in the development of a competent oocyte. Indeed, mtDNA alterations may predispose to chromosome nondisjunction, resulting in infertility due to a reduced vitality and quality of oocytes and embryos. In this methods paper, the multiple displacement amplification approach was applied in combination with next-generation sequencing (NGS) to amplify and sequence, in single-end, the entire mtDNA of single human oocytes to directly construct genomic NGS libraries, and subsequently, to highlight and quantify the mutations they presented. The bioinformatic workflow was carried out with a specific ad hoc developed in-house software. This approach proved to be sensitive and specific, also highlighting the mutations present in heteroplasmy, showing deletion, insertion or substitution mutations in the genes involved in the respiratory chain, even if the found variants were benign or of uncertain meaning. The analysis of mtDNA mutations in the oocyte could provide a better understanding of specific genetic abnormalities and of their possible effect on oocyte developmental competence. This study shows how this approach, based on a massive parallel sequencing of clonally amplified DNA molecules, allows to sequence the entire mitochondrial genome of single oocytes in a short time and with a single analytical run and to verify mtDNA mutations.

Correlation of the position and status of the polar body from the fertilized oocyte to the euploid status of blastocysts

Polar bodies are tiny cells that are extruded during oocyte meiosis and are generally considered not essential for embryonic development. Therefore, polar bodies have been widely used as important materials for the preimplantation genetic diagnosis of human embryos. Recent studies have shown that polar bodies mediate embryonic development and that their morphology is related to embryo quality and developmental potential. However, the relationship between the emission of the polar body and embryonic euploidy remains unclear. In this study, a total of 1,360 blastocyst trophectoderm (TE) biopsies were performed, and blastocyst ploidy results were correlated with the state of polar bodies. The results showed that polar body angle size and polar body status are not directly related to whether the blastocysts are euploid, aneuploid, or mosaic (p > 0.05). Therefore, in the process of clinical embryo selection, embryologists should not predict the euploidy of blastocysts based on the state of polar bodies, thus affecting embryo selection.

Non invasive assessment of human oocytes and embryos in assisted reproduction: Review on present practices and future trends

Oocyte and embryo grading is one of the most important steps in assisted reproductive technology to identify the best among cultured embryos for transfer or vitrification. The most commonly used non-invasive method is morphological assessment of gametes and embryos using a microscope. This method despite being simple and cost-effective has interobserver and intraobserver variability and subjectivity and has little to offer about the physiological state of embryos. This review sourced research articles and reviews pertaining to other non-invasive assessment methodologies from Medline and PubMed to collate latest technologies in vogue and identify novel methodologies of the future. The review assesses the current understanding in oocyte and embryo grading and touches upon novel non-invasive techniques and potential biomarkers to identify the best embryo. The latest available literature on time-lapse imaging, hierarchical algorithms, omics (consisting of proteomics and secretomes), miRNAs, mitochondrial RNAs and artificial intelligence has been accessed to summarize the enormous information available, to identify gaps in current interpretations, to identify emerging technologies and to provide direction for future research. This review will greatly benefit anyone practicing assisted reproduction and clinical embryology.

Does morphological assessment predict oocyte developmental competence? A systematic review and proposed score

PURPOSE

Does existing scientific literature suggest an impact of oocyte dysmorphisms on biological or clinical outcomes of assisted reproduction treatments?

METHODS

Studies of interest were selected from an initial cohort of 6651 potentially relevant records retrieved. PubMed was systematically searched for peer-reviewed original papers and reviews identified by keywords and medical subject heading (MeSH) terms. The most relevant publications were critically evaluated to identify criteria for oocyte morphological evaluation and IVF outcomes. For each morphological abnormality, we generated an oocyte literature score (OLS) through the following procedure: (a) papers showing a negative, absence of, or positive correlation between a given abnormality and IVF outcome were scored 1, 0, and - 1, respectively; (b) the sum of these scores was expressed as a fraction of all analyzed papers; (c) the obtained fraction was multiplied by 10 and converted into decimal number.

RESULT

We identified eleven different dysmorphisms, of which six were extracytoplasmic (COC, zona pellucida, perivitelline space, polar body 1, shape, giant size) and five intracytoplasmic (vacuoles, refractile bodies, SER clusters, granularity, color). Among the extracytoplasmic dysmorphisms, abnormal morphology of the COC generated an OLS of 8.33, indicating a large prevalence (5/6) of studies associated with a negative outcome. Three intracytoplasmic dysmorphisms (vacuoles, SER clusters, and granularity) produced OLS of 7.14, 7.78, and 6.25, respectively, suggestive of a majority of studies reporting a negative outcome.

CONCLUSION

COC morphology, vacuoles, SER clusters, and granularity produced OLS suggestive of a prevalence of studies reporting a negative outcome.

Metformin improves epigenetic modification involved in oocyte growth and embryo development in polycystic ovary syndrome mice model

The possible relationship between dehydroepiandrosterone (DHEA)-induced polycystic ovary syndrome (PCOS) and epigenetic changes (ECs) leading to the impaired oocyte quality, has not been investigated yet. So, this study aimed to provide an insight into the relationship of the impaired oocyte quality with ECs in a mice DHEA-induced PCOS model and to further reveal the effect of metformin treatment. For this purpose, 80 female BALB/C mice were randomly divided into four equal groups, named as the control, sham, (DHEA) and DHEA + Metformin groups. The alterations in acetylation of H4K5 and H4K16, and in methylation of DNA (5MeC) and H3K9 were evaluated using immunocytochemical. Moreover, the expression of Hdac1, Hdac2, Dnmt1, and Dnmt3a genes involved in ECs were analyzed using reverse-transcription polymerase chain reaction. As well, the levels of mitochondrial membrane potential (MMP), oxidative stress (OS), embryo development, ovarian morphology, sexual hormone, ovulatory function, and AMPKα phosphorylation activity were compared in all the studied groups. Metformin attenuated the damages induced by DHEA as indicated by the normalized the estrous cycle, the improved ovarian morphology, the decreased sexual hormone and OS levels, and the increased MMP and AMPKα phosphorylation levels. In the metformin group, the Dnmt1, Dnmt3a, and Hdac2 genes have significantly upregulated compared to the DHEA group. However, metformin was found to have no effect on the expression level of Hdac1. In this regard, significant decrease and increase were observed in both the acetylated H4K16 and methylated H3K9 within MII oocytes in the DHEA + Metformin group compared with the DHEA group. Our results show that metformin could enhance the developmental competence of PCOS oocytes via reducing OS and ECs.

Impact of endometriosis on oocyte morphology in IVF-ICSI: retrospective study of a cohort of more than 6000 mature oocytes

BACKGROUND

Infertility associated with endometriosis can be explained by several non-exclusive mechanisms. The oocyte plays a crucial role in determining embryonic competence and this is particularly relevant for in vitro fertilization (IVF) outcomes. According to some authors, the morphology of oocytes could also be a non-invasive marker of oocyte quality. The aim of this study was to evaluate the relationship between endometriosis and oocyte morphology after controlled ovarian stimulation for intracytoplasmic sperm injection (ICSI) on a large oocyte cohort.

METHODS

Single-center comparative retrospective study in the academic In Vitro Fertilization (IVF) unit of the Lille University Hospital. A total of 596 women treated for IVF-ICSI with ejaculated spermatozoa for sperm alterations were included. They were classified as endometriosis (n = 175) or control groups (n = 401). The morphological evaluation of 2,016 mature oocytes from 348 cycles of patients with endometriosis was compared with that of 4,073 mature oocytes from 576 control cycles. The main outcome measures were Average Oocyte Quality Index (AOQI) and metaphase II oocyte morphological scoring system (MOMS). Comparison of groups was carried out by a mixed linear model and by a generalized estimation equation model with a "patient" random effect to consider that a patient might have several attempts.

RESULTS

No difference in AOQI and MOMS scores was found between endometriosis and control women (adjusted p = 0.084 and 0.053, respectively). In case of endometriosis, there were significantly fewer metaphase II oocytes retrieved, embryos obtained, grade 1 embryos and number of cumulative clinical pregnancies compared to controls. In the endometriosis group, endometriosis surgery was associated with a reduced number of mature oocytes retrieved, and the presence of endometrioma(s) was associated with some abnormal oocyte shapes. Nevertheless, no difference concerning the AOQI and MOMS scores was found in these subgroups.

CONCLUSION

Endometriosis does not have a negative impact on oocytes' morphology in IVF-ICSI.

TRIAL REGISTRATION

On December 16, 2019, the Institutional Review Board of the Lille University Hospital gave unrestricted approval for the anonymous use of all patients' clinical, hormonal and ultrasound records (reference DEC20150715-0002).

Cystic fibrosis transmembrane conductance regulator in follicular fluid and cumulus cells and its relationship with age

Oocyte quality deteriorates with female age and numerous indicators of oocyte quality exist. In the present study, the levels of cystic fibrosis transmembrane conductance regulator (CFTR) in the follicular fluid (FF) and cumulus cells (CCs) of infertile females in 3 different age groups were assessed to determine the relationship between CFTR and female age. The general features of the 3 groups, including age, body mass index, infertility duration, basal hormone levels and the number of retrieved oocytes were compared. The FF CFTR levels of the 3 groups were also compared and multiple age-related indicators of oocyte quality were analyzed, including the estradiol levels on the human chorionic gonadotropin injection day, the morphologically normal oocyte rate and the available or high-quality embryo rate. Immunofluorescence and PCR analyses were performed to examine CFTR expression in CCs around oocytes. The results indicated differences in general features and several indicators of oocyte quality among the 3 groups and significant differences in CFTR. The FF CFTR level was positively correlated with age, which was confirmed by immunofluorescence and PCR. Collectively, these results indicated that CFTR expression in FF and CCs may be associated with oocyte quality based on the age of individuals undergoing the assisted reproduction technique.

Improvement in the epigenetic modification and development competence in PCOS mice oocytes by hydro-alcoholic extract of Nigella sativa during in-vitro maturation: An experimental study

Background

Nigella Sativa (NS) and its active component, thymoquinone, have beneficial protective effects on experimental animal models of polycystic ovary syndrome (PCOS) and different human diseases.

Objective

The present study aimed to investigate the effects of NS hydro-alcoholic extract (NSE) on the oocyte quality of PCOS mice during in vitro maturation.

Materials and Methods

For induction of PCOS, 40 prepubertal 21-days old female B6D2F1 mice (18-22 g body weight) received subcutaneous dehydroepiandrosterone daily. After validation of the model, germinal vesicle-stage oocytes of superovulated mice were collected and placed in the culture medium containing different concentrations (0, 1, 50, and 100 μg/ml) of NSE. For the measurement of developmental competency, some mature oocytes were fertilized with epididymal spermatozoa. Other mature oocytes were assessed for oxidative stress. Also, some mRNA expression levels involved in oocyte maturation and epigenetic modification were evaluated.

Results

The 50 μg/ml NSE treated group showed significantly higher r ates o f maturation, f ertilization, and blastocyst formation in comparison with both control and PCOS groups. A high level of glutathione concentration and glutathione peroxidase mRNA expression, besides a low level of reactive oxygen species content all, were observed in oocytes treated with 50 μg/ml NSE, indicating the modification of oxidative statue. Furthermore, the oocytes in the 50 μg/ml-treated group showed an upregulation of mRNA expression in epigenetic-related genes (Dnmt1 and Hdac1) and maternally derived genes (Mapk and Cdk1), correspondingly downregulation of cyclooxygenase2 mRNA expression, in comparison to other groups.

Conclusion

The results of this study indicated that 50 μg/ml NSE improves oocyte maturation, oxidative statues and epigenetic modifications. These may be the all reasons for the developmental competency in the control and PCOS mice oocytes.

Selection of competent oocytes by morphological criteria for assisted reproductive technologies

Invasive and noninvasive methods are commonly used to select developmentally competent oocytes that can improve the take-home baby rates in assisted reproductive technology (ART) centers. One of the noninvasive methods conventionally utilized to determine competent oocytes is the morphological analysis of cumulus complex, first polar body, zona pellucida, perivitelline space, meiotic spindle, and ooplasm. Successful fertilization, early embryo development, uterine implantation, and healthy pregnancy depend on the quality of oocytes, and morphological evaluation is one of the options used to predict quality levels. In this review, the morphological criteria being utilized in certain ART centers are comprehensively evaluated with special references to their predictive values and potential contributions to selecting high-quality oocytes.

Exposing Mouse Oocytes to MitoQ During In Vitro Maturation Improves Maturation and Developmental Competence

Background and Purpose:

Mitochondrion is the main indicator of oocyte quality and one of the components of oocyte, which is sensitive to oxidative damage during the maturation process. Mitoquinone mesylate (MitoQ) is a strong antioxidant targeting mitochondria as well as anti-apoptotic agent. However, the effect of MitoQ on the quality of oocytes during in vitro maturation (IVM) is still unknown.

Objectives:

This study investigated the possible effects of MitoQ on maturation and developmental competency in mice oocytes.

Materials and Methods:

The oocytes were collected at germinal vesicle stage from 6-8-week old female NMRI mice and then cultured in TCM-199 medium supplemented with 0, 0.01, 0.02 and 0.04 µM MitoQ. The sham group was treated with DMSO (0.01% v.v). Then intracellular Glutathione (GSH), reactive oxygen species (ROS) levels, mitochondria membrane potential (ΔΨm), as well as in vitro fertilization (IVF) rate in the 18-20 h matured oocytes and metaphase II (MII) oocytes (in vivo-control), were assessed.

Results:

The results showed that between three dose of MitoQ, the 0.02 µM significantly increased nuclear maturation rate, GSH level, fertilization rate and blastulation (92.6, 231.7, 90.19 and 81.66%, respectively) than the in vitro-control (71.14, 152, 78.84 and 73.50%, respectively) and more comparable to that of the in vivo matured oocytes (100, 243.5, 92.10 and 83%, respectively). Also, the mitochondria membrane potential in the 0.02 µM MitoQ was significantly higher compared with those in the other groups (4.4). However, the intracellular ROS level in 0.02 µM MitoQ was significantly decreased (38.72%) compared to in vitro-control (82.2%) and was similar to the in vivo-control (33.5%).

Conclusion:

The results indicated that supplementation of IVM medium with MitoQ (specially 0.02 µM) enhance maturation and fertilization rate. In conclusion, MitoQ might be considered as a novel component that could be added to IVM media.

Potential of Auraptene in Improvement of Oocyte Maturation, Fertilization Rate, and Inflammation in Polycystic Ovary Syndrome Mouse Model

Polycystic ovary with poor-quality oocytes has remained problematic in polycystic ovary syndrome (PCOS) patients. It is well documented that the inflammation and production of reactive oxygen species (ROS) in PCOS ovaries are significantly higher than normal voluntaries. In this study, we hypothesized that auraptene (AUR), as a coumarin derivative with anti-inflammatory properties, may be effective in improvement of oocyte maturation and fertilization rate in PCOS patients. For this purpose, PCOS model was induced in NMRI mice and confirmed by ovarian histopathology observations and hormonal assays. PCOS-induced mice were administrated with AUR (PCOS-AUR) and metformin (PCOS-MET), and their effects on inflammation, apoptosis rate, oocyte maturation, and in vitro fertilization capacity were determined and compared with those normal and PCOS animals treated with sesame oil (PCOS-sesame oil) and no treatment (PCOS). Treatment with AUR and MET decreased the inflammation and apoptosis rates in PCOS mice compared with PCOS animals with no treatment. PCOS-AUR and PCOS-MET oocytes also showed higher intracellular glutathione and lower ROS concentrations compared with PCOS mice, indicating improved oocyte maturation rate. PCOS-AUR and PCOS-MET groups showed higher percentages of expansion rate and MII stage oocytes, and lower rate of abnormal oocytes compared with PCOS with no treatment. The rate of fertilization in the oocytes isolated from PCOS-AUR and PCOS-MET groups was higher than PCOS-sesame oil and PCOS groups. Our findings suggest that AUR can be considered as a potential candidate for improvement of oocyte maturation and fertilization capacity in PCOS patients, comparable to MET.

The antioxidant curcumin postpones ovarian aging in young and middle-aged mice

Reproductive senescence is accompanied by a reduced number and quality of ovarian follicles in response to the accumulation of free radicals and the process of apoptosis. Having selected mice as models, we examined the hypothesis that curcumin as an antioxidant and anti-inflammatory agent might prevent or retard ovarian aging. Female NMRI 21-day-old mice were divided into control, vehicle and curcumin groups. In the treatment group the mice received curcumin at 100mgkg-1day-1 intraperitoneally. After 6, 12 and 33 weeks several parameters were examined including ovarian reserve, oocyte quality, oxidative status, invitro fertilisation and expression of ovulation-related (growth differentiation factor 9 (GDF-9) and bone morphogenetic protein 15 (BMP-15)) and anti-aging-related (sirtuin 1 (SIRT-1) and SIRT-3) genes. Curcumin treatment up to 12 and 33 weeks resulted in increased ovarian volume and number of follicles and was associated with elevated anti-Müllerian hormone and oestrogen and diminished FSH serum levels. Furthermore, enhanced oocyte maturation, fertilisation and embryo development plus reduced oxidative stress were seen in the curcumin group. Also, the expression of GDF-9, BMP-15, SIRT-1 and SIRT-3 genes was increased in the curcumin group. Concerning gestational age, the findings of the study suggested that administration of curcumin could delay the process of oocyte aging in a mouse model.

Dynactin pathway-related gene expression is altered by aging, but not by vitrification

The storage of surplus oocytes by cryopreservation (OC) is a widely used tool in assisted reproductive technology, but there is a great debate about the effects of cryopreservation on oocyte competence. It is known that OC may affect meiotic spindles but remains unclear if OC may increase the risk of aneuploidy. The aim of this study was to test the effects of OC and women aging on the expression of cytokinesis-related genes playing an important role in the segregation of chromosomes (DCTN1, DCTN2, DCTN3, DCTN6 and PLK1). Results highlighted that OC do not modify the expression of the selected genes, whereas women aging modulate the expression of all transcripts, confirming that aging is the crucial factor affecting meiosis and aneuploidy risk. A new role for Dynactin and PLK1 was shed in light, providing information on the ageing process in the oocyte which may be associated to reduced fertility.

Thymoquinone reduces intracytoplasmic oxidative stress and improves epigenetic modification in polycystic ovary syndrome mice oocytes, during in-vitro maturation

Although in-vitro maturation (IVM) of oocytes has been presented as an alternative treatment to traditional stimulated in-vitro fertilization, the culture condition can be improved by natural antioxidants. Thus, we investigated the protective effect of Thymoquinone (TQ) during IVM in the polycystic ovary syndrome (PCOS) mice model. The induction of PCOS was made by dehydroepiandrosterone via subcutaneous injection, in prepubertal female B6D2F1-mice. After 21 days later, germinal vesicle (GV)-stage-oocytes were extracted and incubated in IVM media containing 0, 1.0, 10.0, and 100.0 μM of TQ. To assess fertilization and blastulation rates, after 22-24 hr, the treated oocytes were fertilized in-vitro with epididymal spermatozoa. Some other oocytes were evaluated for maturation, epigenetic, and oxidative stress markers. Similarly, the mRNA expression of epigenetic enzymes genes (Dnmt1 and Hdac1), three maternally derived genes (Mapk, CyclinB, and Cdk1) and apoptosis-related genes (Bax and Bcl2) were assessed. Our results showed that the maturation, fertilization, and blastulation rates were significantly higher in the 10.0 μM TQ-treated group compared with the untreated group and likewise with in-vivo matured oocytes. The Bax expression was reduced in 10.0 μM TQ matured oocytes, but Bcl2, Dnmt1, Hdac1, Cdk1, and Mapk were upregulated in this group compared to other groups. Furthermore, dimethylation of histone-3 at lysine-9 (H3K9m2) and DNA methylation were significantly increased whereas H4K12 acetylation (H4K12ac) was decreased in the 10.0 μM TQ-treated group in comparison with control and in-vivo matured oocytes. Therefore, our results are suggesting that 10.0 μM TQ may enhance the developmental competence of PCOS oocytes via the modulation of oxidative stress and epigenetic alterations.

Role of PCSK9 in lipid metabolic disorders and ovarian dysfunction in polycystic ovary syndrome

BACKGROUND

Proprotein convertase subtilisin/kexin type 9 (PCSK9) plays a critical role in the cholesterol metabolism by negatively regulating the low-density lipoprotein receptor (LDLR). Lipid metabolic and ovarian disorders are the common clinical manifestation of polycystic ovary syndrome (PCOS). Here, we intended to elucidate the role of PCSK9 in the pathogenesis of PCOS conducted on a human population in case-control design and animal part in an interventional study.

METHODS

We firstly investigated the serum levels of PCSK9 in 46 PCOS patients compared with 49 healthy women as controls, and then developed a PCOS mouse model induced by dehydroepiandrosterone (DHEA) and a high-fat diet (HFD) to determine the role of PCSK9 in abnormal lipid metabolism and ovarian dysfunction of PCOS in four groups (n = 40 per group): control, PCOS mice, PCOS plus alirocumab group, and PCOS plus vehicle group. The expression of PCSK9 in their serum, hepatic and ovarian tissues, serum lipid profiles and hormones were measured. Additionally, mRNA and protein expression levels of LDLR in hepatic and ovarian tissues, ovarian morphology and function were determined. Finally, we used freshly isolated theca-interstitial cells (TICs) and granulosa cells (GCs) from prepubertal normal mice to explore the effect of PCSK9 on LDL uptake of the cells.

RESULTS

Serum PCSK9 concentrations were higher in PCOS patients than normal controls (P < 0.05). The PCOS model mice exhibited significantly increased serum levels of total cholesterol (TC), LDL-C and high-density lipoprotein-cholesterol (HDL-C; P < 0.001, P < 0.001, P = 0.0004, respectively). Moreover, the serum PCSK9 protein level was significantly increased in PCOS mice (P = 0.0002), which positively correlated with serum LDL-C (r = 0.5279, P = 0.0004) and TC (r = 0.4151, P = 0.035). In both liver and ovary of PCOS mice, PCSK9 mRNA and protein levels were significantly increased (P < 0.05), but LDLR levels were significantly decreased (P < 0.05). Furthermore, alirocumab inhibiting PCSK9 partly increased in LDLR expression in both liver and ovary in PCOS mice, also ameliorated the lipid metabolic disorders and pathological changes of ovarian morphology and function and serum reproductive hormones but not in the PCOS plus vehicle group. In vitro experiment, recombinant PCSK9 decreased LDL uptake in TICs and GCs (P < 0.001, P = 0.0011, respectively), which were partly reversed by alirocumab (P < 0.001, P = 0.012, respectively).

CONCLUSION

Abnormal high expression of PCSK9 in the blood, liver and ovary may be involved in the pathogenesis of PCOS by affecting lipid metabolism and ovarian function, and the inhibition of PCSK9 may partly reverse the pathological changes of PCOS. Our research suggests a possibility of PCSK9 as a new attractive target for diagnosis and treatment of PCOS.

Improvement of oocyte in vitro maturation from mice with polycystic ovary syndrome by human mesenchymal stromal cell-conditioned media

The outcome of in vitro maturation (IVM) in the patients with polycystic ovary syndrome (PCOS) is poor. Abnormal intraovarian paracrine interplay alters microenvironment for oocyte development through folliculogenesis and decreases developmental competence of oocytes in patients with PCOS. Mesenchymal stromal cells (MSCs) secrete a variety of cytokines and growth factors that could promote oocyte maturation in vitro. Thus, in the current study we aimed to evaluate the effect of human bone marrow MSC-conditioned media (hBM-MSC-CM), as a supplement, to enrich IVM medium for PCOS germinal vesicles (GVs). For this purpose, oocytes at GV and metaphase II (MII) stages were harvested from PCOS mice. The GVs were randomly divided into four groups and incubated for 24 hours in an IVM medium (TCM199, as the control group) or TCM199 supplemented by 25%, 50%, and 75% of hBM-MSC-CM (PCOS-CM25, PCOS-CM50, and PCOS-CM75 groups, respectively) so as to evaluate which dose(s) could enhance maturation rate of the GVs and their subsequent in vitro fertilization (IVF) outcome. Furthermore, MII oocytes and their subsequent IVF outcome were considered as the in vivo matured (PCOS-IVO) group. The data showed that supplementation of IVM medium with 50% hBM-MSC-CM significantly increased cytoplasmic and nuclear maturation of the GVs (P < 0.001), and also fertilization and two-cell rate (P < 0.001) and blastocyst formation (P < 0.01) of in vitro matured oocytes from mice with PCOS. Overall, higher oocyte maturation and fertilization outcome in PCOS-CM50 group proposed that enrichment of IVM medium with hBM-MSC-CM could be considered as a promising approach to improve IVM of PCOS oocytes.

Quercetin improves developmental competence of mouse oocytes by reducing oxidative stress during in vitro maturation

Quercetin is a natural flavonoid with strong antioxidant activity. In the present study, we evaluate the influence of different concentrations of quercetin (QT) on intracytoplasmic oxidative stress and glutathione (GSH) concentration, during in vitro maturation (IVM) and fertilization in mouse oocytes. IVM was carried out in the presence of control (QT0), 5 (QT5), 10 (QT10), and 20 (QT20) μg/mL of QT. Nuclear maturation, intracellular GSH and ROS content were evaluated following the IVM. In these oocytes, we subsequently evaluated the effect of QT supplementation on embryo development, including 2-cell, 8-cell, and blastocyst rate. The results of the present study showed that the supplementation of 10 μg/mL QT in maturation medium increased the number of MII oocytes. In addition, fertilization and blastocyst rate in QT10 treatment group were significantly higher in comparison to the other groups, and elevated the amount of intracellular GSH content compared to other QT concentrations and control groups. The intracellular ROS level was the lowest among oocytes matured in Q5 and Q10 treatment groups. This result suggested that quercetin dose-dependently improves nuclear maturation and embryo development, via reducing intracytoplasmic oxidative stress in mature oocyte.

Impact of oocytes with CLCG on ICSI outcomes and their potential relation to pesticide exposure

BACKGROUND

Oocyte quality is a key limiting factor in female fertility which is primarily reflected in morphological features. Centrally located cytoplasm granulation (CLCG) is one type of cytoplasmic dimorphism exhibited by oocytes that could be linked to pesticide exposure with a significant risk of decreased ICSI outcomes.

METHODS

This retrospective study included 633 women who were part of an intracytoplasmic spermatozoa injection (ICSI) program between 2009 and 2011. The participants lived in the Picardy region of France and had been exposed to pesticides. The participants were divided in two groups based on prevalence of oocytes with CLCG (LCLCG [n = 83]: low prevalence of oocytes with CLCG under 25%. HCLCG [n = 68]: high prevalence of CLCG over 75%). The embryological and clinical outcomes were analysed for both groups and were calculated using the difference between the two values.

RESULTS

Results for couples with HCLCG compared to LCLCG showed a decrease in embryo cleavage, ongoing pregnancy, and live birth rates (82%, 14%, 13% vs 99%, 32%, 30%, respectively).The early miscarriage rate was increased (47% vs 11%), with an OR of 3.1 (95%CI [2.1-4.1]). Due to high pesticide exposure (over 3000 g/ha), there is a higher risk of a resulting disturbed oocyte cohort with a high prevalence of CLCG over 75%.

CONCLUSION

The high prevalence of oocytes with CLCG over 75% has a negative effect on embryos and the general ICSI clinical outcomes. Furthermore, a putative association between pesticide exposure and risk of CLCG was identified, justifying the need for further research and a potential need to find alternative assisted reproductive technologies for these couples.

TRIAL REGISTRATION

Tabacfertimasc. ID number: ID2011-A00634-37 ; registered 2011/2/8.

Intracytoplasmic oxidative stress reverses epigenetic modifications in polycystic ovary syndrome

In polycystic ovary syndrome (PCOS), substantial genetic and environmental alterations, along with hyperandrogenism, affect the quality of oocytes and decrease ovulation rates. To determine the mechanisms underlying these alterations caused specifically by an increase in plasma androgens, the present study was performed in experimentally-induced PCOS mice. As the study model, female B6D2F1 mice were treated with dehydroepiandrosterone (DHEA, 6 mg per 100 g bodyweight). After 20 days, oocytes at the germinal vesicle and metaphase II stages were retrieved from isolated ovaries and subsequent analyses of oocyte quality were performed for each mouse. DHEA treatment resulted in excessive abnormal morphology and decreased polar body extrusion rates in oocytes, and was associated with an increase in oxidative stress. Analysis of fluorescence intensity revealed a significant reduction of DNA methylation and dimethylation of histone H3 at lysine 9 (H3K9) in DHEA-treated oocytes, which was associated with increased acetylation of H4K12. Similarly, mRNA expression of DNA methyltransferase-1 and histone deacetylase-1 was significantly decreased in DHEA-treated mice. There was a significant correlation between excessive reactive oxygen species (ROS) production and increased histone acetylation, which is a novel finding and may provide new insights into the mechanism causing PCOS. The results of the present study indicate that epigenetic modifications of oocytes possibly affect the quality of maturation and ovulation rates in PCOS, and that the likely mechanism may be augmentation of intracytoplasmic ROS.

High-fat diets exaggerate endocrine and metabolic phenotypes in a rat model of DHEA-induced PCOS

Polycystic ovary syndrome (PCOS) is a complex endocrine and metabolic disorder with unclear etiology and unsatisfactory management. Effects of diets on the phenotype of PCOS were not fully understood. In the present study, we applied 45 and 60% high-fat diets (HFDs) on a rat model of PCOS induced by postnatal DHEA injection. We found that both DHEA and DHEA+HFDs rats exhibited reproductive abnormalities, including hyperandrogenism, irregular cycles and polycystic ovaries. The addition of HFDs, especially 60% HFDs, exaggerated morphological changes of ovaries and a number of metabolic changes, including increased body weight and body fat content, impaired glucose tolerance and increased serum insulin levels. Results from qPCR showed that DHEA-induced increased expression of hypothalamic androgen receptor and LH receptor were reversed by the addition of 60% HFDs. In contrast, the ovarian expression of LH receptor and insulin receptor mRNA was upregulated only with the addition of 60% HFDs. These findings indicated that DHEA and DHEA+HFDs might influence PCOS phenotypes through distinct mechanisms: DHEA affects the normal function of hypothalamus-pituitary-ovarian axis through LH, whereas the addition of HFDs exaggerated endocrine and metabolic dysfunction through ovarian responses to insulin-related mechanisms. We concluded that the addition of HFDs yielded distinct phenotypes of DHEA-induced PCOS and could be used for studies on both reproductive and metabolic features of the syndrome.

Epigenetic heterogeneity of developmentally important genes in human sperm: implications for assisted reproduction outcome

The molecular basis of male infertility is poorly understood, the majority of cases remaining unsolved. The association of aberrant sperm DNA methylation patterns and compromised semen parameters suggests that disturbances in male germline epigenetic reprogramming contribute to this problem. So far there are only few data on the epigenetic heterogeneity of sperm within a given sample and how to select the best sperm for successful infertility treatment. Limiting dilution bisulfite sequencing of small pools of sperm from fertile donors did not reveal significant differences in the occurrence of abnormal methylation imprints between sperm with and without morphological abnormalities. Intracytoplasmic morphologically selected sperm injection was not associated with an improved epigenetic quality, compared to standard intracytoplasmatic sperm injection. Deep bisulfite sequencing (DBS) of 2 imprinted and 2 pluripotency genes in sperm from men attending a fertility center showed that in both samples with normozoospermia and oligoasthenoteratozoospermia (OAT) the vast majority of sperm alleles was normally (de)methylated and the percentage of epimutations (allele methylation errors) was generally low (<1%). However, DBS allowed one to identify and quantify these rare epimutations with high accuracy. Sperm samples not leading to a pregnancy, in particular in the OAT group, had significantly more epimutations in the paternally methylated GTL2 gene than samples leading to a live birth. All 13 normozoospermic and 13 OAT samples leading to a child had <1% GTL2 epimutations, whereas one (7%) of 14 normozoospermic and 7 (50%) of 14 OAT samples without pregnancy displayed 1–14% GTL2 epimutations.

MAPK3/1 (ERK1/2) and Myosin Light Chain Kinase in Mammalian Eggs Affect Myosin-II Function and Regulate the Metaphase II State in a Calcium- and Zinc-Dependent Manner

Vertebrate eggs are arrested at metaphase of meiosis II, a state classically known as cytostatic factor arrest. Maintenance of this arrest until the time of fertilization and then fertilization-induced exit from metaphase II are crucial for reproductive success. Another key aspect of this meiotic arrest and exit is regulation of the metaphase II spindle, which must be appropriately localized adjacent to the egg cortex during metaphase II and then progress into successful asymmetric cytokinesis to produce the second polar body. This study examined the mitogen-activated protein kinases MAPK3 and MAPK1 (also known as ERK1/2) as regulators of these two related aspects of mammalian egg biology, specifically testing whether this MAPK pathway affected myosin-II function and whether myosin-II perturbation would produce some of the same effects as MAPK pathway perturbation. Inhibition of the MEK1/2-MAPK pathway with U0126 leads to reduced levels of phosphorylated myosin-regulatory light chain (pMRLC) and causes a reduction in cortical tension, effects that are mimicked by treatment with the myosin light chain kinase (MLCK) inhibitor ML-7. These data indicate that one mechanism by which the MAPK pathway acts in eggs is by affecting myosin-II function. We further show that MAPK or MLCK inhibition induces loss of normal cortical spindle localization or parthenogenetic egg activation. This parthenogenesis is dependent on cytosolic and extracellular calcium and can be rescued by hyperloading eggs with zinc, suggesting that these effects of inhibition of MLCK or the MAPK pathway are linked with dysregulation of ion homeostasis.

Impaired oocyte quality induced by dehydroepiandrosterone is partially rescued by metformin treatment

The present study evaluated the influence of hyperandrogenism on oocyte quality using a murine PCOS model induced by dehydroepiandrosterone (DHEA) and further explored the effect of metformin treatment. Female BALB/c mice were treated with a vehicle control or DHEA (6 mg /100 g body weight) or DHEA plus metformin (50 mg /100 g body weight) for 20 consecutive days. DHEA-induced mice resembled some characters of human PCOS, such as irregular sexual cycles and polycystic ovaries. After the model validation was completed, metaphase II (MII) oocytes were retrieved and subsequent analyses of oocyte quality were performed. DHEA-treated mice yielded fewer MII oocytes, which displayed decreased mtDNA copy number, ATP content, inner mitochondrial membrane potential, excessive oxidative stress and impaired embryo development competence compared with those in control mice. Metformin treatment partially attenuated those damages, as evidenced by the increased fertilization and blastocyst rate, ATP content, GSH concentration and GSH/GSSG ratio, and decreased reactive oxygen species levels. No significant difference in normal spindle assembly was observed among the three groups. During in vitro maturation (IVM), the periods of germinal vesicle breakdown (GVBD) and the first polar body (PB1) extrusion were extended and the maturation rate of GVBD oocytes was decreased in DHEA mice compared with controls. Metformin treatment decreased the time elapsed of GVBD while had no effect on PB1 extrusion. These results indicated that excessive androgen is detrimental to oocyte quality while metformin treatment is, directly or indirectly, beneficial for oocyte quality improvement.

Microfluidic method of pig oocyte quality assessment in relation to different follicular size based on lab-on-chip technology

Since microfollicular environment and the size of the follicle are important markers influencing oocyte quality, the aim of this study is to present the spectral characterization of oocytes isolated from follicles of various sizes using lab-on-chip (LOC) technology and to demonstrate how follicle size may affect oocyte quality. Porcine oocytes (each, n = 100) recovered from follicles of different sizes, for example, from large (>5 mm), medium (3–5 mm), and small (<3 mm), were analyzed after preceding in vitro maturation (IVM). The LOC analysis was performed using a silicon-glass sandwich with two glass optical fibers positioned “face-to-face.” Oocytes collected from follicles of different size classes revealed specific and distinguishable spectral characteristics. The absorbance spectra (microspectrometric specificity) for oocytes isolated from large, medium, and small follicles differ significantly (P < 0.05) and the absorbance wavelengths were between 626 and 628 nm, between 618 and 620 nm, and less than 618 nm, respectively. The present study offers a parametric and objective method of porcine oocyte assessment. However, up to now this study has been used to evidence spectral markers associated with follicular size in pigs, only. Further investigations with functional-biological assays and comparing LOC analyses with fertilization and pregnancy success and the outcome of healthy offspring must be performed.

Follicular fluid anti-Müllerian hormone: a predictive marker of fertilization capacity of MII oocytes

PURPOSE

The present study aimed to correlate anti-Müllerian hormone (AMH) levels in follicular fluid (FF) with oocyte maturity stages, morphological quality of metaphase II (MII) oocyte and fertilization capacity of MII oocytes.

METHODS

A total of 92 infertile women undergoing controlled ovarian stimulation and intracytoplasmic sperm injection were analyzed. Patients were divided into two groups according to age: <35 years (n = 43) and ≥35 years (n = 49). An FF sample was obtained from a single dominant follicle in each patient for a total of 92 follicular fluid samples analyzed. AMH levels in serum and follicular fluid were measured by enzyme-linked immunosorbent assay. Mature MII oocytes, zygotes, and embryos were assessed for morphological quality.

RESULTS

Serum AMH levels were significantly higher in patients aged <35 years. No correlation was observed between FF AMH level and oocyte maturation stages or morphological quality of MII oocyte. Significantly lower FF AMH levels were observed in fertilized MII oocytes than in non-fertilized MII oocytes in patients aged <35 years (2.56 ± 2.0 ng/ml vs. 4.81 ± 4.14 ng/ml; p = 0.032).

CONCLUSIONS

The present study revealed no correlation between FF AMH and oocyte maturity stage or morphological quality of MII oocyte. However, FF AMH might be a predictive marker for fertilization capacity of MII oocytes.

The role of ionizing radiaton on ovulation rate and oocyte morphology in mouse

We investigated the effects of ionizing radiation on maturation ability and radiosensitivity of oocytes enclosed in preantral and antral follicles. Balb/c female mice received total body single dose gamma radiation (7.2 Gy) at the diestrous to proestrous transition period. In the first experiment, spontaneously ovulated oocytes were collected from irradiated animals. In the second experiment, irradiated animals were allowed to superovulate to assess the ovarian function. The spontaneous ovulation rate of the follicles exposed at antral stage was significantly lower than the sham-irradiated mice (p < 0.01), and most of the oocytes were found at the metaphase I stage. Oocyte morphology and the ovulation rate of the follicles exposed at preantral stage were similar to the sham-irradiated group. Minimal morphological abnormalities were observed in the oocytes and the polar body as well. The superovulation response of all the irradiated animals was lower than the respective control animals. The superovulation rate was significantly lower in the first ovulation after irradiation (p < 0.01). In conclusion, our findings indicate that total body gamma irradiation, on a basis of estrous cycle stages, leads to ovulation failure in the antral stage while causes abnormal oocyte morphology in the preantral stage follicles in mice.

The predictive value of high-magnification sperm morphology examination on ICSI outcomes in the presence of oocyte dysmorphisms

PURPOSE

To evaluate the relationship between oocyte dysmorphisms and IMSI outcomes

METHODS

Data of IMSI cycles performed in 332 patients were included in this study. Patients were included only if presented more than four and less than 30 oocytes upon oocyte retrieval. Patients who underwent IMSI were matched, concerning female age and sperm parameters, with patients who underwent ICSI in the same period (n = 332). The two groups (ICSI and IMSI) were compared with regard to treatment outcomes. The influence of IMSI on fertilization and embryo quality on D3 and D5, when oocyte dysmorphisms were present was analyzed.

RESULTS

A total of 6444 oocytes were morphologically evaluated and injected. Regardless of the oocyte quality, IMSI performance was a determinant of the increased odds of development to high quality embryo on D3 (OR: 1.98; CI: 1.54-2.56) and D5 (OR: 3.27; CI: 1.61-6.66).

CONCLUSIONS

The selection of a morphologically normal spermatozoon under high-magnification is associated with increased embryo quality, regardless of the oocyte morphology. The injection of a spermatozoon, selected under high-magnification, into a morphologically normal oocyte leads to the highest probability of developing high quality embryos.

The spatial and mechanical challenges of female meiosis

Recent work shows that cytokinesis and other cellular morphogenesis events are tuned by an interplay among biochemical signals, cell shape, and cellular mechanics. In cytokinesis, this includes cross-talk between the cortical cytoskeleton and the mitotic spindle in coordination with cell cycle control, resulting in characteristic changes in cellular morphology and mechanics through metaphase and cytokinesis. The changes in cellular mechanics affect not just overall cell shape, but also mitotic spindle morphology and function. This review will address how these principles apply to oocytes undergoing the asymmetric cell divisions of meiosis I and II. The biochemical signals that regulate cell cycle timing during meiotic maturation and egg activation are crucial for temporal control of meiosis. Spatial control of the meiotic divisions is also important, ensuring that the chromosomes are segregated evenly and that meiotic division is clearly asymmetric, yielding two daughter cells - oocyte and polar body - with enormous volume differences. In contrast to mitotic cells, the oocyte does not undergo overt changes in cell shape with its progression through meiosis, but instead maintains a relatively round morphology with the exception of very localized changes at the time of polar body emission. Placement of the metaphase-I and -II spindles at the oocyte periphery is clearly important for normal polar body emission, although this is likely not the only control element. Here, consideration is given to how cellular mechanics could contribute to successful mammalian female meiosis, ultimately affecting egg quality and competence to form a healthy embryo.

Relevance and Methodology for the Morphological Analysis of Oocyte Quality in IVF and ICSI

Oocytes collected from patients following ovarian stimulation exhibit varying qualities. The quality of oocytes has an effect on its subsequent fertilization, developmental competence post-fertilization and the viability of resultant embryos. The aim of this article was to review the morphological criteria devised for assessment of oocyte quality by ordinary light and polarized light microscopy before IVF or ICSI. The parameters employed in the evaluation of oocyte morphology include the appearance of: structure of the cumulus–oocyte complex, oocyte cytoplasm, perivitelline space, zona pellucida, polar body and meiotic spindle.

Influence of follicular fluid GDF9 and BMP15 on embryo quality

OBJECTIVE

To evaluate the association between follicular fluid levels of propeptide and mature forms of growth differentiation factor (GDF) 9 and bone morphogenetic protein (BMP) 15 with subsequent oocyte and embryo quality.

DESIGN

Prospective clinical study.

SETTING

University hospital.

PATIENT(S)

Eighty-one infertile patients who underwent in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI).

INTERVENTION(S)

The expression levels of the propeptide and mature forms of follicular fluid GDF9 and BMP15 were determined by western blot analysis. The levels of follicular fluid hormones (FSH, E2, and P) were measured with automated chemiluminescent enzyme immunoassays.

MAIN OUTCOME MEASURE(S)

The relationships between the levels of GDF9 and BMP15, hormones, oocyte maturation, and embryo quality.

RESULT(S)

Mature GDF9 levels were significantly correlated with the nuclear maturation of oocytes. The mean mature GDF9 level was 4.87±0.60 in the high-embryo-quality group and 1.45±0.81 in the low-embryo-quality group. There were no statistically significant differences in embryo quality among the patients regarding propeptide GDF9 and BMP15 expression status. There was a negative correlation between follicular fluid levels of P and the mature form of GDF9.

CONCLUSION(S)

Higher mature GDF9 levels in the follicular fluid were significantly correlated with oocyte nuclear maturation and embryo quality.

Correlation of spermiogram profiles with DNA damage in sperm cells of infertile men: a comet assay study

We have investigated a relationship between DNA damage in sperm and spermiogram profiles in the infertile men. Twenty-one non-smoking infertile men <40 years of age with no systemic or genetic disease were randomly selected from the pool of infertile couples applied to our clinic. Sperm samples were collected and evaluated according to WHO guidelines. DNA damage of sperm cells was assessed using neutral comet assay. Fifty cells per slide and two slides per sample were scored to evaluate DNA damage. The cells were visually classified into four categories based on DNA migration such as undamaged (UD), little damage (LD), moderate damage (MD) and significant damage (SD). Total comet scores (TCS) were calculated as: 1×UD + 2×LD + 3×MD + 4×SD. There was a negative correlation between the percentage of slow- and in situ-motion sperm cells in spermiograms and TCS (p < 0.001 and p < 0.05, respectively). The relationship between the percentage of non-motile sperm cells and TCS was negative (p < 0.001). This study provides new evidence that DNA damage in spermatozoa and sperm motility parameters are negatively correlated. We suggest that evaluation of sperm DNA by the neutral comet assay may be valuable to use in fertility research.

Intracytoplasmic injection of morphologically selected spermatozoa (IMSI) improves outcome after assisted reproduction by deselecting physiologically poor quality spermatozoa

PURPOSE

We used computer assisted sperm selection (MSOME) during cycles of intracytoplasmic sperm injection to test whether this technique improves results over traditional ICSI protocols. We also used the TUNEL assay to test whether MSOME could deselect physiologically abnormal spermatozoa.

METHODS

Individual spermatozoa were examined with MSOME. Normal and abnormal spermatozoa were tested for the level of DNA fragmentation using TUNEL assay. In a prospective, randomized trial, patients were selected for standard ICSI, or IMSI techniques. We tested the two groups for biological and clinical parameters.

RESULTS

64.8% of spermatozoa, otherwise selectable for ICSI, were characterized by abnormalities after computer-assisted sperm analysis. These sperm were also characterized by an increase in the level of DNA fragmentation. We noted an increase in embryo quality, pregnancy and implantation rates after computerized sperm selection during ICSI procedures.

CONCLUSIONS

Computerised selection of spermatozoa during ICSI procedures deselects physiological abnormal spermatozoa and improves clinical results.

Recombinant human follicle-stimulating hormone produces more oocytes with a lower total dose per cycle in assisted reproductive technologies compared with highly purified human menopausal gonadotrophin: a meta-analysis

BACKGROUND

Human menopausal gonadotrophins and recombinant human follicle stimulating hormone are the two main gonadotrophin products utilized for controlled ovarian stimulation in assisted reproductive technologies. In this meta-analysis, the number of oocytes was designated as the most relevant endpoint directly resulting from ovarian stimulation, and therefore where the drug effect may be estimated with the best sensitivity.

METHODS

All published randomized controlled trials on ovarian stimulation comparing the two gonadotrophin products were evaluated. Internal validity was determined using Chalmers' validated scale. If trials did not meet the established quality criteria, a sensitivity analysis assessed the stability of the results. The comparison of continuous variables was conducted following the weighted mean difference and the standardized mean difference (Cohen's effect size) with the random model. Given the known relationship of baseline conditions on treatment endpoints, results were adjusted for age, body mass index and type of infertility.

RESULTS

Sixteen studies involving 4040 patients were included. Treatment with human menopausal gonadotrophins resulted in fewer oocytes (-1.54; 95% CI: -2.53 to -0.56; P < 0.0001) compared to recombinant human follicle-stimulating hormone. When adjusting for baseline conditions, the mean difference estimate was -2.10 (95% CI: -2.83 to -1.36; P < 0.001). A higher total dose of human menopausal gonadotrophin was necessary (mean difference, 235.46 IU [95% CI: 16.62 to 454.30; P = 0.03]; standardized mean difference, 0.33 [95% CI: 0.08 to 0.58; P = 0.01]). The pregnancy absolute risk difference (RD [hMG-r-hFSH]) for fresh transfers was 3% (P = 0.051), and the relative risk 1.10 (P = 0.06). When adjusted for baseline conditions, the relative risk was 1.04 (P = 0.49) and absolute difference was 0.01 (P = 0.34), respectively.

CONCLUSIONS

Because baseline conditions are predictive of outcome, meta-analytic results are more sensitive when these variables are considered. Using an endpoint closely associated with the stimulation period, sufficient sensitivity is achieved to compare gonadotrophin treatments. As the largest meta-analysis published to date on this subject, treatment with human menopausal gonadotrophins is characterized by fewer oocytes and a higher total dose. When considering only fresh transfers, pregnancy rates were similar.

Theca-specific estrogen receptor-alpha knockout mice lose fertility prematurely

Estrogen receptor-alpha (Esr1) mediates estrogen action in regulating at all levels of the hypothalamic-pituitary-ovarian axis. Whereas the importance of Esr1 in hypothalamus and pituitary has been demonstrated by loss of fertility in the neuron- and pituitary-specific Esr1 knockout mice, whether Esr1 plays a critical role in the ovary remains to be determined. In the ovary, Esr1 is mainly expressed in the theca/interstitial cells and germinal epithelium and thus is believed to mediate estrogen action in these cells. In this study, we assessed the importance of Esr1 in the ovarian theca cells in regulating female reproduction. The Cre-LoxP approach was used to selectively delete the Esr1 gene in the theca cells, and the reproductive consequence of the deletion was measured. Adolescent theca-specific Esr1 knockout (thEsr1KO) mice (<4 months of age) are fertile and cycling. However, they begin to display an erratic pattern of estrous cycles and become infertile before they reach the age of 6 months. The ovaries of thEsr1KOmice (>or=4 months) have fewer corpora lutea but more antral follicles than the age-matching wild-type mice. The numbers of 17-hydroxylase-expressing cells are largely increased in the interstitium of the thEsr1KO mouse ovary. Interestingly, whereas basal levels of serum testosterone and FSH were mildly elevated, LH level was either markedly lower or undetectable in the thEsr1KO mice. When superstimulated by exogenous gonadotropins, thEsr1KO mice released significantly fewer oocytes that wild-type littermates and developed multiple hemorrhagic cysts. Taken together, this study demonstrates that theca Esr1 plays a critical role in regulating female reproduction.

Relationship between first polar body morphology before intracytoplasmic sperm injection and fertilization rate, cleavage rate, and embryo quality

OBJECTIVES

To evaluate the influence of the morphology of the first polar body (PB) on intracytoplasmic sperm injection (ICSI) outcomes.

METHODS

The morphology of the first PB was assessed in 3177 metaphase II oocytes and classified as: intact and normal size, fragmented, or enlarged size. The rates of fertilization, cleavage, and embryo quality were evaluated on day 2.

RESULTS

The rates of fertilization, cleavage, and formation of good quality embryos resulting from the insemination of oocytes with an enlarged first PB (20.7%, 18.7%, and 5.0%, respectively) were significantly lower than those for oocytes with an intact first PB of normal size (70.8%, 62.5%, and 19%, respectively) or a fragmented first PB (69.7%, 60.5%, and 17.1%, respectively). Rates did not differ significantly between oocytes with an intact first PB of normal size and oocytes with a fragmented first PB (P>0.05).

CONCLUSIONS

The presence of an enlarged PB is related to poorer rates of fertilization, cleavage, and top quality embryos. However, identification of first PB fragmentation does not seem to interfere with ICSI outcomes.