Gonadotrophin stimulation in IVF alters the immune cell profile in follicular fluid and the cytokine concentrations in follicular fluid and serum

Interleukin-6 Concentration in Single-Embryo Medium Is Associated with Blastocyst Formation

IL-6 plays an important role in oogenesis in humans. However, at the preimplantation stage, IL-6 production and the role in embryo development remain unclear. In this study, IL-6 concentrations in single-embryo media were analyzed. In addition, the association between IL-6 production and blastocyst formation was investigated. Single-embryo culture media from 194 embryos were collected on day 6 after fertilization and divided into four groups according to the developmental stage of the corresponding embryo, as follows: cleavage stage group, morula-early blastocyst group, unavailable full blastocyst group, and available full blastocyst group. IL-6 concentrations were significantly lower in the cleavage stage group than in the morula-early blastocyst group (p = 0.009), in the unavailable full blastocyst group (p = 0.003), and in the available full blastocyst group (p < 0.001). Logistic regression analysis showed that IL-6 concentration in single-embryo medium was significantly associated with blastocyst formation (odds ratios β1 = 1.876, 95% CI 1.433 to 2.644, p < 0.0001). Therefore, IL-6 was produced by human preimplantation embryos throughout the preimplantation stage and may play a role in embryo development.

Associations between phthalate metabolites and cytokines in the follicular fluid of women undergoing in vitro fertilization

Many studies have showed that phthalates have reproductive and embryonic toxicity, while the potential mechanisms are mostly unknown. Inflammation may play a mediating part in phthalate exposure and adverse reproductive endpoints. A cross-sectional survey was conducted to investigate the associations of phthalate metabolites with inflammatory cytokines in the follicular fluid (FF) of women undergoing in vitro fertilization (IVF). We determined the levels of eight phthalate metabolites and five cytokines in the FF of 76 women, including interleukin (IL)- 6, IL-8, IL-10, monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor-α (TNF-α). The associations of individual phthalate exposure with cytokines in FF samples were explored by multiple linear regression. We further evaluated the combined effects of multiple phthalate exposures on FF levels of cytokines by using Bayesian kernel machine regression (BKMR) models. We found that there was a positive relationship between mono-ethyl phthalate (MEP) and IL-6 in the FF (percent change:12.4%; 95% CI: 1.3%, 24.9%). In contrast, elevated mono-benzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP) and %MEHP levels were associated with decreased MCP-1. In the BKMR models, phthalate metabolite mixtures were positively associated with TNF-α when the mixtures were lower than 65th percentile compared with their medians. In the stratified analyses, MEHP was inversely associated with MCP-1 among women with BMI ≥ 23 kg/m2 (test for interaction <0.05). Our results suggest that certain phthalate metabolites or their mixtures may alter levels of inflammatory cytokines in the FF, and further research is necessary to elucidate the mechanisms underlying the relationship between phthalates exposure, ovarian dysfunction and adverse pregnancy outcomes.

Expression and T cell regulatory action of the PD-1 immune checkpoint in the ovary and fallopian tube

PROBLEM

Immune cell trafficking and surveillance within the ovary and fallopian tube are thought to impact fertility and also tumorigenesis in those organs. However, little is known of how native cells of the ovary and fallopian tube interact with resident immune cells. Interaction of the Programmed Cell Death Protein-1 (PD-1/PDCD-1/CD279) checkpoint with PD-L1 is associated with downregulated immune response. We have begun to address the question of whether PD-1 ligand or its receptors (PD-L1/-L2) can regulate immune cell function in these tissues of the female reproductive tract.

METHOD OF STUDY

PD-1 and ligand protein expression was evaluated in human ovary and fallopian tube specimens, the latter of which included stages of tubal cell transformation and early tumorigenesis. Ovarian expression analysis included the determination of the proteins in human follicular fluid (HFF) specimens collected during in vitro fertilization procedures. Finally, checkpoint bioactivity of HFF was determined by treatment of separately-isolated human T cells and the measurement of interferon gamma (IFNγ).

RESULTS

We show that membrane bound and soluble variants of PD-1 and ligands are expressed by permanent constituent cell types of the human ovary and fallopian tube, including granulosa cells and oocytes. PD-1 and soluble ligands were present in HFF at bioactive levels that control T cell PD-1 activation and IFNγ production; full-length checkpoint proteins were found to be highly enriched in HFF exosome fractions.

CONCLUSION

The detection of PD-1 checkpoint proteins in the human ovary and fallopian tube suggests that the pathway is involved in immunomodulation during folliculogenesis, the window of ovulation, and subsequent egg and embryo immune-privilege. Immunomodulatory action of receptor and ligands in HFF exosomes is suggestive of an acute checkpoint role during ovulation. This is the first study in the role of PD-1 checkpoint proteins in human tubo-ovarian specimens and the first examination of its potential regulatory action in the contexts of normal and assisted reproduction.

Resveratrol regulates insulin resistance to improve the glycolytic pathway by activating SIRT2 in PCOS granulosa cells

Scope

Insulin resistance (IR) has a close relationship with the main clinical manifestations of patients with PCOS; hence, the research and development of new drugs to treat PCOS by improving IR is a desiderate task at present. Resveratrol (RES) possesses a variety of beneficial pharmacological functions, such as antioxidation, anti-inflammatory, regulating glucose, and lipid metabolism. However, whether RES could improve IR and the underlying mechanisms remained unclear in PCOS.

Methods and results

SD rats received a high-fat diet and letrozole for 30 days to establish the PCOS model and then intervened with RES for 30 days. The results demonstrated that RES played a protective role on the IR in PCOS rats, which significantly decreased the levels of blood glucose and serum insulin, up regulated the expression of IGF1R, and down regulated the expression of IGF1. In vitro, KGN cells were treated with insulin, RES, and AGK2, respectively. We found that a high dose of insulin (4μg/mL) significantly inhibited KGN cell viability, decreased the level of lactic acid, and increased the level of pyruvate, while RES (25μM) attenuated the growth-inhibitory effect, as well as increased the level of lactic acid and decreased the level of pyruvate after high levels of insulin treatment. Simultaneously, RES up regulated the expression level of the crucial rate-limiting enzymes relating to glycolytic pathways, such as LDHA, HK2, and PKM2. Furthermore, AGK2 remarkably inhibited the expression level of SIRT2, which was similar to the same negative effects processed by insulin. Meanwhile, RES overtly repaired the glycolysis process by reversing the levels of lactic acid and pyruvate, together with up regulating the expression level of LDHA, HK2, and PKM2, after AGK2 treatment.

Conclusion

RES could effectively improve insulin resistance and restore the glycolysis pathway by regulating SIRT2, which may contribute to attenuating the ovarian damage of PCOS rats and provide a potential treatment for patients with PCOS.

Oocyte maturity, oocyte fertilization and cleavage-stage embryo morphology are better in natural compared with high-dose gonadotrophin stimulated IVF cycles

RESEARCH QUESTION

Does high-dose gonadotrophin stimulation have an effect on oocyte and early-stage embryo development?

DESIGN

This was a retrospective study including 616 natural cycle IVF (NC-IVF) and 167 conventional IVF (cIVF) cycles. In total, 2110 oocytes were retrieved and analysed in fresh cycles. In NC-IVF, only human chorionic gonadotrophin was applied to trigger ovulation. In cIVF, antagonist protocols with daily 150-300 IU of human menopausal gonadotrophins were performed. The effect of gonadotrophins on oocyte and early-stage embryo development was analysed. Primary outcomes were the occurrence of mature (metaphase II) oocytes, zygotes and embryos with good morphology at the cleavage stage 2 days after oocyte retrieval.

RESULTS

The mature oocyte rate (number of mature oocytes/number of retrieved oocytes) was higher in NC-IVF than cIVF cycles (89% versus 82%, adjusted odds ratio [aOR] 1.79, P = 0.001), as was the zygote rate per oocyte retrieved (70% versus 58%, aOR 1.76, P = 0.001) and the zygote rate per mature oocyte (79% versus 71%, aOR 1.62, P = 0.001). The percentage of zygotes that developed into cleavage-stage embryos was no different. For the transferred embryos, the probability of having a good embryo morphology with four blastomeres and a fragmentation of <10% (score 0) in cleavage-stage embryos was found to be higher in NC-IVF (proportional aOR for four blastomeres 2.00, P < 0.001; aOR 1.87 for a fragmentation score of 0, P = 0.003).

CONCLUSIONS

Oocyte maturity, oocyte fertilization and morphology of the cleavage-stage embryo are affected by high-dose gonadotrophin stimulation in fresh IVF cycles.

Oxidative Stress-Related Signaling Pathways Predict Oocytes' Fertilization In Vitro and Embryo Quality

Oocyte development and fertilization are largely influenced by the microenvironment of the follicular fluid (FF), and the exploration of its molecular/metabolic composition may help in improving in vitro fertilization (IVF) outcomes. Here, the concentrations of molecules related to oxidative stress/inflammation were measured in FF from follicles at oocyte retrieval during IVF. Here, the FF antioxidant potential was correlated with the number of retrieved/mature oocytes and the number of fertilized ones. FF collected from the follicles of normal fertilized oocytes presented an elevated antioxidant capability, lower levels of pro-inflammatory molecules (i.e., IL-6, IL-8, IL-12, TGF-β, and HIF-1α), and a higher IL-10 concentration. FF samples from follicles at oocyte retrieval that resulted in top-quality embryos displayed a peculiar antioxidant capability and a further decrease in proinflammatory molecules when compared with FF, giving rise to poor-quality embryos. Finally, pro-inflammatory molecules were lower and accompanied by a high antioxidant capability in samples giving rise to successful embryo implantation. The antioxidant capability and IL-10 displayed a good predictive ability for fertilization and embryo quality. Overall, our data showed the great influence of oxidative stress on the oocytes' fertilization, and shed light on the importance of controlling the inflammatory and oxidative status of FF to obtain good-quality embryos with significant implantation potential.

A Case-Control Study of Follicular Fluid Cytokine Profiles in Women with Diminished Ovarian Reserve

Ovarian reserve is an important determinant of a woman's reproductive potential, and women with diminished ovarian reserve (DOR) often seek in vitro fertilization (IVF). The underlying etiology of DOR is unknown, but follicular fluid cytokine concentrations likely play a role in follicular development and maturation. The present study seeks to investigate the expression of cytokines in follicular fluid (FF) of women with DOR undergoing IVF and explore correlated functional pathways. One hundred ninety-four women undergoing ovarian stimulation were recruited at the time of oocyte retrieval. Women were classified as having DOR if they met one or more of the following criteria: AMH < 1 ng/ml, FSH > 10 mIU/ml, and/or AFC < 10. Controls included women undergoing IVF for male factor, tubal factor due to tubal ligation, or planned oocyte cryopreservation (non-oncologic). The concentrations of 480 cytokines and related growth factors in follicular fluid were determined using a multiplex immunoassay. Fifty-nine cytokines had significantly different concentrations (53 higher and 6 lower) in the DOR relative to the control group after adjusting for age and body mass index (BMI) (false discovery rate; FDR < 0.1). Using the most informative 44 biomarkers as indicated by a random forest (RF) model, an area under the curve (AUC) of 0.78 was obtained. Thus, follicular microenvironment differs between women with DOR and normal ovarian reserve. The differentially expressed cytokines belong to diverse processes that are primarily involved in follicular maturation and ovulation. These changes may play an important role in treatment outcomes in women with DOR.

IL-6 of follicular fluid and outcome of in vitro fertilization

The quality of an oocyte is influenced by its microenvironment, which includes cumulus cells and follicular fluid, as well as cells of the immune system and their products. The ovarian interleukins, which are secreted by the granulosa cells and other immune cells within the ovaries and follicles, regulate various functions between the cells. IL-6 is a cytokine that is present in the follicular fluid and may affect the quality of oocytes. There are some inconsistencies in the literature regarding the concentration of interleukin 6 in the follicular fluid. The main objective of this study was to examine whether the concentration of interleukin 6 in the follicular fluid affects the outcome of IVF. This study involved 83 patients who underwent IVF. Follicular fluid was used as the biological material for the analysis. Examination of the obtained follicular fluid and collection of oocytes under a stereomicroscope was performed in the embryological laboratory. The concentration of IL-6 in the follicular fluid was analyzed. IVF and ICSI methods were used as the fertilization methods. Pregnancy was confirmed by the positive serum β-hCG level. The software package SPSS 20 was used for statistical data processing. Analysis of the follicular fluid samples showed a correlation between the concentration of IL-6 in the follicular fluid and the outcome of IVF. The concentration of IL-6 in the follicular fluid was higher in patients with confirmed pregnancy (9.55 ± 7.47 ng/ml). Based on our results, we conclude that the concentration of IL-6 affects the outcome of IVF. If the range of IL-6 concentration is between 3,67 ng/ml and 10 ng/ml, we can expect good IVF outcome with vital pregnancy.

Gonadotropin Stimulation Reduces the Implantation and Live Birth Rate but Not the Miscarriage Rate of Embryos Transferred When Compared to Unstimulated In Vitro Fertilization

Research suggests that gonadotropin stimulation in in vitro fertilization (IVF) treatment affects embryo quality and the endometrium that might influence embryo implantation, placentation and establishment of a viable pregnancy. We assessed the impact of gonadotropin stimulation on implantation, live birth and miscarriage rates per transferred embryo by comparing stimulated and unstimulated IVF treatment. In a cohort of 728 couples, 1310 IVF cycles with successful embryo transfer were analysed; 857 cycles were stimulated with gonadotropins > 75 IU/day (333 poor responder < 4 oocytes; 524 normal responders), and 453 were unstimulated. In total, 1913 fresh cleavage-stage embryos were transferred. Zygote but no embryo selection was performed, and supernumerous zygotes were vitrified. The implantation rate was defined as number of sonographically detected amniotic sacs; live birth rate as number of children born per transferred embryo. Modified mixed effect Poisson regression was used to account for the dependency of cycles and embryos within the same women and the same transfer cycle. Adjustments were made for maternal age, parity, primary or secondary infertility and indication for IVF. Per transferred embryo, implantation rates (rate ratio (RR) 1.37; 95% CI 1.04-1.81; p = 0.028; aRR 1.42; 95% CI 1.10-1.84; p = 0.008) and live birth rates (RR 1.33; 95% CI 0.95-1.86; p = 0.093; aRR 1.38; 95% CI 1.01-1.88; p = 0.044) were higher in NC-IVF compared to cIVF normal responders. Miscarriage did not differ (RR 0.99; 95% CI 0.59-1.65; p = 0.965; aRR 0.90; 95% CI 0.52-1.53 p = 0.698). Similar results were obtained in poor responders. The study suggests an impact of gonadotropin stimulation on the implantation potential of embryos.

No Effect of Inactivated SARS-CoV-2 Vaccination on in vitro Fertilization Outcomes: A Propensity Score-Matched Study

Purpose

Patients and Methods

Results

Conclusion

Single-Cell Sequencing Reveals an Intrinsic Heterogeneity of the Preovulatory Follicular Microenvironment

The follicular microenvironment, including intra-follicular granulosa cells (GCs), is responsible for oocyte maturation and subsequent ovulation. However, the functions of GCs and cellular components of the follicular microenvironment in preovulatory follicles have not been extensively explored. Here, we surveyed the single-cell transcriptome of the follicular microenvironment around MII oocytes in six human preovulatory follicles in in vitro fertilization. There were six different cell types in the preovulatory follicles, including GCs and various immune cells. In GCs, we identified nine different functional clusters with different functional transcriptomic profiles, including specific clusters involved in inflammatory responses and adhesive function. Follicular macrophages are involved in immune responses, extracellular matrix remoulding and assist GCs in promoting the oocyte meiotic resumption. Interestingly, we observed that the specific terminal state subcluster of GCs with high levels of adhesive-related molecules should result in macrophage recruitment and residence, further contributing to an obvious heterogeneity of the immune cell proportion in preovulatory follicles from different patients. Our results provide a comprehensive understanding of the transcriptomic landscape of the preovulatory follicular microenvironment at the single-cell level. It provides valuable insights into understanding the regulation of the oocyte maturation and ovulation process, offering potential clues for the diagnosis and treatment of oocyte-maturation-related and ovulation-related diseases.

Live-Birth Prediction of Natural-Cycle In Vitro Fertilization Using 57,558 Linked Cycle Records: A Machine Learning Perspective

BACKGROUND

Natural-cycle in vitro fertilization (NC-IVF) is an in vitro fertilization (IVF) cycle without gonadotropins or any other stimulation of follicular growth. Previous studies on live-birth prediction of NC-IVF were very few; the sample size was very limited. This study aims to construct a machine learning model to predict live-birth occurrence of NC-IVF using 57,558 linked cycle records and help clinicians develop treatment strategies.

DESIGN AND METHODS

The dataset contained 57,558 anonymized register patient records undergoing NC-IVF cycles from 2005 to 2016 filtered from 7bsp;60,732 records in the Human Fertilisation and Embryology Authority (HFEA) data. We selected matching records and features through data filtering and feature selection methods. Two groups of twelve machine learning models were trained and tested. Eight metrics, e.g., F1 score, Matthews correlation coefficient (MCC), the area under the receiver operating characteristic curve (AUC), etc., were computed to evaluate the performance of each model.

RESULTS

Two groups of twelve models were trained and tested. The artificial neural network (ANN) model performed the best in the machine learning group (F1 score, 70.87%; MCC, 50.37%; and AUC score, 0.7939). The LogitBoost model obtained the best scores in the ensemble learning group (F1 score, 70.57%; MCC, 50.75%; and AUC score, 0.7907). After the comparison between the two models, the LogitBoost model was recognized as an optimal one.

CONCLUSION

In this study, NC-IVF-related datasets were extracted from the HFEA data, and a machine learning-based prediction model was successfully constructed through this largest NC-IVF dataset currently. This model is universal and stable, which can help clinicians predict the live-birth success rate of NC-IVF in advance before developing IVF treatment strategies and then choose the best benefit treatment strategy according to the patients' wishes. As "use less stimulation and back to natural condition" becomes more and more popular, this model is more meaningful in the decision-making assistance system for IVF.

Raman Spectrum of Follicular Fluid: A Potential Biomarker for Oocyte Developmental Competence in Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in reproductive women where abnormal folliculogenesis is considered as a common characteristic. Our aim is to evaluate the potential of follicular fluid (FF) Raman spectra to predict embryo development and pregnancy outcome, so as to prioritize the best promising embryo for implantation, reducing both physiological and economical burdens of PCOS patients. In addition, the altered metabolic profiles will be identified to explore the aetiology and pathobiology of PCOS. In this study, follicular fluid samples obtained from 150 PCOS and 150 non-PCOS women were measured with Raman spectroscopy. Individual Raman spectrum was analyzed to find biologic components contributing to the occurrence of PCOS. More importantly, the Raman spectra of follicular fluid from the 150 PCOS patients were analyzed via machine-learning algorithms to evaluate their predictive value for oocyte development potential and clinical pregnancy. Mean-centered Raman spectra and principal component analysis (PCA) showed global differences in the footprints of follicular fluid between PCOS and non-PCOS women. Two Raman zones (993-1,165 cm^-1 and 1,439-1,678 cm^-1) were identified for describing the largest variances between the two groups, with the former higher and the latter lower in PCOS FF. The tentative assignments of corresponding Raman bands included phenylalanine and β -carotene. Moreover, it was found that FF, in which oocytes would develop into high-quality blastocysts and obtain high clinical pregnancy rate, were detected with lower quantification of the integration at 993-1,165 cm^-1 and higher quantification of the integration at 1,439-1,678 cm^-1 in PCOS. In addition, based on Raman spectra of PCOS FF, the machine-learning algorithms via the fully connected artificial neural network (ANN) achieved the overall accuracies of 90 and 74% in correctly assigning oocyte developmental potential and clinical pregnancy, respectively. The study suggests that the PCOS displays unique metabolic profiles in follicular fluid which could be detected by Raman spectroscopy. Specific bands in Raman spectra have the biomarker potential to predict the embryo development and pregnancy outcome for PCOS patients. Importantly, these data may provide some valuable biochemical information and metabolic signatures that will help us to understand the abnormal follicular development in PCOS.

Kallistatin in follicular fluid of women with endometriosis and its correlation with IVF outcome

BACKGROUND

Endometriosis (EM) affects 10% women of reproductive age and alters fertility. Its management is still debated notably the timing of surgery and ART in infertility. Kallistatin (KS) is an endogenous protein that regulates differential signaling pathways and biological functions. However, the function and the underlying molecular mechanism in EM and its correlation with in vitro fertilization (IVF) outcome have not been determined. The purpose of this study was to evaluate KS concentrations in follicular fluid (FF) of women with EM and controls women without EM who underwent IVF with embryo transfer (IVF-ET).

METHODS

FF KS concentrations from 40 patients with EM and 40 non-EM patients were measured by ELISA.

RESULTS

Compared with the non-EM patients, patients with EM had lower KS levels in FF (281.67 ± 104.60 vs. 490.70 ± 216.33 pg/ml). The rates of fertilization (61.64 ± 22.42 vs. 71.00 ± 24.39%), available embryo (45.96 ± 19.83 vs. 50.61 ± 26.26%), and top-quality embryo (12.71 ± 21.01 vs. 16.04 ± 16.87%) were significantly lower in the EM group than in the control group. The KS concentrations in the FF of women who conceived consequent to the treatment were significantly higher than those from women who did not in the combined EM and control groups.

CONCLUSIONS

These results indicate that the KS concentration in FF could be used as a predictor for IVF-ET outcomes. This may contribute to the pathologic mechanism responsible for the poor outcome of IVF in patients with EM.

Whole-Genome Methylation Analysis Revealed ART-Specific DNA Methylation Pattern of Neuro- and Immune-System Pathways in Chinese Human Neonates

The DNA methylation of human offspring can change due to the use of assisted reproductive technology (ART). In order to find the differentially methylated regions (DMRs) in ART newborns, cord blood maternal cell contamination and parent DNA methylation background, which will add noise to the real difference, must be removed. We analyzed newborns’ heel blood from six families to identify the DMRs between ART and natural pregnancy newborns, and the genetic model of methylation was explored, meanwhile we analyzed 32 samples of umbilical cord blood of infants born with ART and those of normal pregnancy to confirm which differences are consistent with cord blood data. The DNA methylation level was lower in ART-assisted offspring at the whole genome-wide level. Differentially methylated sites, DMRs, and cord blood differentially expressed genes were enriched in the important pathways of the immune system and nervous system, the genetic patterns of DNA methylation could be changed in the ART group. A total of three imprinted genes and 28 housekeeping genes which were involved in the nervous and immune systems were significant different between the two groups, six of them were detected both in heel blood and cord blood. We concluded that there is an ART-specific DNA methylation pattern involved in neuro- and immune-system pathways of human ART neonates, providing an epigenetic basis for the potential long-term health risks in ART-conceived neonates.

The follicular fluid adipocytokine milieu could serve as a prediction tool for fertility treatment outcomes

RESEARCH QUESTION

Can the adipocytokine milieu of the follicular niche improve the ability to predict treatment outcomes in infertile patients?

DESIGN

Follicular fluid samples from overweight patients were analysed and compared with samples from matched normal-weight patients. Concentrations of adiponectin, chemerin, C-reactive protein, interleukin-6 (IL-6), IL-10, IL-18, insulin, leptin, prolactin, resistin, tumour necrosis factor alpha (TNF-α) and bone morphogenetic protein-15 (BMP-15) were assessed by multiple magnetic bead immunoassay (MMBI) and enzyme-linked immunosorbent assay and correlated with fertility treatment outcomes.

RESULTS

Analysis of samples from 22 overweight and 22 normal-weight patients demonstrated that TNF-α can predict oocyte maturation rate. When stratified by body mass index (BMI), IL-10 emerges as a better predictor of oocyte maturation in normal-weight patients. Prolactin was a negative predictor for fertilization rate in the full cohort, and this prediction power was lost upon stratification. No adipocytokines were predictive of blastulation rate, and only age remained predictive. BMP-15 was a strong predictor of high-quality blastulation in the full cohort, more so in the normal-weight population.

CONCLUSIONS

The adipocytokine milieu of the follicular fluid provides a snapshot of the growing oocyte's environment and can help predict fertility treatment outcomes, fine-tuning understanding of the dysregulation caused by increasing BMI. Inflammatory cytokines can predict oocyte maturation; prolactin, oocyte competence; and BMP-15, high-quality blastulation. Further analysis of these findings with a larger sample size and assessing individual oocytes will help shed more light on the clinical significance of these findings.

Gonadotrophin stimulation reduces follicular fluid hormone concentrations and disrupts their quantitative association with cumulus cell mRNA

RESEARCH QUESTION

Do follicular fluid hormone concentrations and the mRNA expression of LHCG, FSH and androgen receptors, aromatase and anti-Müllerian hormone (AMH) in cumulus granulosa cells differ in naturally matured and stimulated follicles?

DESIGN

Cross-sectional study involving 57 natural cycle IVF (NC-IVF) and 36 conventional gonadotrophin-stimulated IVF (cIVF) cycles performed between 2014 and 2016. cIVF was performed by ovarian stimulation with human menopausal gonadotrophin and gonadotrophin-releasing hormone antagonists. Hormone concentrations were determined in the follicular fluid of the leading follicle, and mRNA concentrations were quantified by reverse transcription polymerase chain reaction in RNA extracted from granulosa cells of the cumulus oophorus complex obtained from these fluids.

RESULTS

Follicular fluid hormone concentrations were significantly lower in cIVF compared with NC-IVF follicles. Median concentrations were 0.50 and 14.5 mIU/ml for LH (P < 0.001), 16.1 and 46.5 nmol/l for testosterone (P < 0.001), 1270 and 2675 nmol/l for oestradiol (P < 0.001), and 12.3 and 28.9 pmol/l for AMH (P < 0.001), respectively. In cumulus granulosa cells, mRNA concentrations for LH receptor, FSH receptor, androgen receptor, aromatase and AMH did not differ between cIVF and NC-IVF follicles. Several hormone and mRNA concentrations were quantitatively associated in natural cycles such as follicular fluid AMH and cumulus granulosa cells AMH RNA (r² = 0.107, P = 0.013), follicular fluid testosterone and cumulus granulosa cell AMH RNA (r² = 0.158, P = 0.002), follicular fluid oestradiol and cumulus granulosa cell AMH RNA (r² = 0.105, P = 0.014) and follicular fluid oestradiol and aromatase (r² = 0.113, P = 0.011). In contrast, these associations were not observed in stimulated cycles.

CONCLUSION

These findings indicate some effects of gonadotrophin stimulation on follicular physiology, which could be a cause for the previously suggested lower oocyte quality in cIVF compared with NC-IVF.

Raman spectroscopy of follicular fluid and plasma with machine-learning algorithms for polycystic ovary syndrome screening

Polycystic ovary syndrome (PCOS) is the main cause of anovulatory infertility and affects women throughout their lives. The specific diagnostic method is still under investigation. In the present study, we aimed to identify the metabolic tracks of the follicular fluid and plasma samples from women with PCOS by performing Raman spectroscopy with principal component analysis and spectral classification models. Follicular fluid and plasma samples obtained from 50 healthy (non-PCOS) and 50 PCOS women were collected and measured by Raman spectroscopy. Multivariate statistical methods and different machine-learning algorithms based on the Raman spectra were established to analyze the results. The principal component analysis of the Raman spectra showed differences in the follicular fluid between the non-PCOS and PCOS groups. The stacking classification models based on the k-nearest-neighbor, random forests and extreme gradient boosting algorithms yielded a higher accuracy of 89.32% by using follicular fluid than the accuracy of 74.78% obtained with plasma samples in classifying the spectra from the two groups. In this regard, PCOS may lead to the changes of metabolic profiles that can be detected by Raman spectroscopy. As a novel, rapid and affordable method, Raman spectroscopy combined with advanced machine-learning algorithms have potential to analyze and characterize patients with PCOS.

Human Adipose-Derived Stem Cells' Paracrine Factors in Conditioned Medium Can Enhance Porcine Oocyte Maturation and Subsequent Embryo Development

An essential requirement for the success of in vitro maturation (IVM) of the oocyte is to provide an optimal microenvironment similar to in vivo conditions. Recently, somatic cell-based coculture or supplementation of a conditioned medium during IVM has been performed to obtain better quality of oocytes, because they mimic the in vivo reproductive tract by secreting paracrine factors. In this study, human adipose-derived stem cells (ASC) and their conditioned medium (ASC-CM) were applied to IVM of porcine oocytes to evaluate the effectiveness of ASC on oocyte development and subsequent embryo development. In results, both ASC and ASC-CM positively influence on oocyte maturation and embryo development by regulating growth factor receptors (VEGF, FGFR, and IGFR), apoptosis (BCL2), cumulus expansion (PTGS2, HAS2, and TNFAIP6), and oocyte maturation-related genes (GDF9 and BMP15). In particular, the fluorescence intensity of GDF9 and BMP15 was markedly upregulated in the oocytes from the ASC-CM group. Furthermore, significantly high levels of growth factors/cytokine including VEGF, bFGF, IGF-1, IL-10, and EGF were observed in ASC-CM. Additionally, the ASC-CM showed active scavenging activity by reducing the ROS production in a culture medium. Consequently, for the first time, this study demonstrated the effect of human ASC-CM on porcine oocyte development and the alteration of mRNA transcript levels in cumulus–oocyte complexes.

Investigating apoptotic, inflammatory, and growth markers in poor responders undergoing natural in vitro fertilization cycles: a pilot study

This study investigates follicular fluid (FF) from patients with poor and normal ovarian response undergoing natural assisted reproductive technology cycles. We report about (1) cell-free DNA (cfDNA), which reflects apoptosis; (2) corticotropin-releasing hormone (CRH); (3) interleukin (IL)-15, which reflects inflammation; (4) granulocyte colony-stimulating factor (G-CSF); (5) vascular endothelial growth factor (VEGF); and (6) insulin-like growth factor I (IGF-I), which reflects follicular growth. Forty-four poor responders and 44 normal responders-according to the Bologna criteria-were recruited. FF samples were prepared for cfDNA quantification employing Q-PCR and for CRH, IL-15, G-CSF, VEGF, and IGF-I quantification employing ELISA. Statistically nonsignificant different levels of FF cfDNA, CRH, IL-15, VEGF, and IGF-I were observed. Interestingly, statistically significant higher G-CSF levels were observed in normal responders (302.48 ± 474.36 versus 200.10 ± 426.79 pg/mL, P = 0.003). Lower cfDNA integrity was observed in cycles resulting in clinical pregnancy for both groups (normal: 0.07 ± 0.04 versus 0.25 ± 0.17 ng/μL, P < 0.001; poor: 0.10 ± 0.06 versus 0.26 ± 0.12 ng/μL, P < 0.001). The results predominantly showcase similarities between normal and poor responders pertaining to inflammatory, apoptotic, and growth factors. This may be attributed to the employment of natural cycles in order to exclude controlled ovarian stimulation as a factor-indicating its detrimental effect. As G-CSF levels presented significantly higher in normal responders, its vital role in understanding a compromised ovarian response is highlighted.

Effects of Human Endothelial Progenitor Cell and Its Conditioned Medium on Oocyte Development and Subsequent Embryo Development

Human endothelial progenitor cells (EPCs) secrete numerous growth factors, and they have been applied to regenerative medicine for their roles in angiogenesis as well as neovascularization. Angiogenesis is one of the essential factors for the maturation of ovarian follicles; however, the physiological function of EPCs or their derivatives on in vitro culture systems has not been fully understood. The aim of this study was to evaluate the effectiveness of EPCs and their conditioned medium (EPC-CM) on oocyte development and subsequent embryo development. In the results, the oocyte development and subsequent embryo development were significantly improved in EPCs and the EPC-CM group. In addition, markedly increased levels of growth factors/cytokines, such as basic fibroblast growth factor (bFGF), vascular endothelial growth factor (VEGF), insulin growth factor-1 (IGF-1), interleukin-10 (IL-10), and epidermal growth factor (EGF), were observed in medium from the EPC-CM group. Additionally, EPC-CM after in vitro maturation (IVM) had significantly decreased reactive oxygen species (ROS) levels compared to those of other groups. Transcriptional levels of growth factor receptor-related genes (FGFR2, IGF1R) and anti-apoptotic-related gene (BCL2) were significantly upregulated in cumulus cells/oocytes from the EPC-CM group compared with those from the control. Furthermore, the expression levels of cumulus expansion-related genes (PTGS2, TNFAIP6, HAS2) and oocyte-maturation-related factors (GDF9, BMP15) were significantly enhanced in the EPC-CM group. Consequently, the present study provides the first evidence that EPC-CM contains several essential growth factors for oocyte development by regulating genes involved in oocyte maturation.

Impact of embryo quality and endometrial thickness on implantation in natural cycle IVF

Purpose

The aim of this study is to assess the effect of the endometrial thickness and embryo quality on the implantation potential in natural cycle IVF (NC-IVF).

Methods

A retrospective single-center study was performed on 552 single embryo transfers after NC-IVF. The ‘quality' of the embryos was evaluated trough the number and regularity of blastomeres, degree of fragmentation, and nuclear content of cells. Endometrial thickness was measured in millimeters with transvaginal ultrasound on the day of hCG application.

Results

Our findings showed a statistically significant difference in successful implantation until a plateau of 10 mm is reached (p = 0.001). Only one pregnancy was achieved where endometrial thickness was less than 7 mm, and this resulted in an early miscarriage. The predictors of favorable implantation were fragmentation (≤ 10%, p < 0.05) and the number of blastomeres (preferably 8-cell, p < 0.01) on day 3. Embryo quality (R = 0.052) and endometrial thickness (R = 0.18) were closely related to pregnancy rate. The overall implantation rate per embryo transfer was 18.8%.

Conclusions

Embryo quality and endometrial thickness have a significant impact on implantation in NC-IVF. Highest implantation potential has an 8-cell embryo with ≤ 10% fragmentation in the third day following oocyte retrieval. Endometrial thickness of at least 7 mm seems to be the optimal edge of successful pregnancy.

Interleukin 6 in follicular fluid reduces embryo fragmentation and improves the clinical pregnancy rate

PURPOSE

The aim of this study was to evaluate the role of interleukin 6 in embryo development in the in vitro fertilization cycles.

METHODS

This was a retrospective cohort study. One hundred and three women undergoing in vitro fertilization and embryo transfer due to a tubal factor were included in the study. The follicular fluid IL-6 levels on oocyte retrieval day from each patient were determined by ELISA. The relationships between follicular fluid IL-6 levels and IVF cycle parameters were investigated.

RESULTS

The levels of follicular fluid IL-6 were not affected by the use of drugs for superovulation or by estrogen. In addition, follicular fluid IL-6 levels did not affect the number of oocytes retrieved or the MII oocyte rate. High levels of follicular fluid IL-6 correlated with a significant increase in the rates of clinical pregnancy. Follicular fluid IL-6 levels did not affect the cell number or the blastomere symmetry of day 3 embryos, but it did significantly reduce the embryo fragmentation rate.

CONCLUSIONS

High levels of follicular fluid IL-6 improved the rates of clinical pregnancy and reduce embryo fragmentation.

Roadmap to pregnancy in the first 7 days post-insemination in the cow: Immune crosstalk in the corpus luteum, oviduct, and uterus

The first 7 days post-insemination are critical for establishment of pregnancy. The pre-ovulatory luteinizing hormone (LH) surge induces ovulation through disruption of the follicle structure that elucidates pro-inflammatory (Th1) responses. Various types of immune cells are recruited into the corpus luteum (CL) to regulate luteal angiogenesis and progesterone (P4) secretion into the circulation to establish pregnancy. The active sperm-uterine crosstalk also induces Th1 responses, mainly via Toll-like receptor (TLR) 2/4 signaling pathway in vitro. The endometrial glands serve as sensors for sperm signals, which trigger Th1 responses. Conversely, the sperm-oviduct binding generates anti-inflammatory (Th2) responses to support sperm survival until fertilization. It is well-established that embryo-maternal crosstalk starts after the embryo hatches out from the zona pellucida (ZP). However most recently, it was shown that the 16-cell stage bovine embryo starts to secrete interferon-tau (IFNT) that induces Th2 immune responses in the oviduct. Once developing embryos descend into the uterine horn, they induce Th2 responses with interferon-stimulated genes (ISGs) expression in the uterine epithelium and local immune cells mainly via IFNT release. Likewise, multiple embryos in the uterus of superovulated donor cows on D7 post-insemination induce Th2 immune responses with ISGs expressions in circulating immune cells. These findings strongly suggest that the maternal immune system reacts to the embryo during the first 7 days post-insemination to induce fetal tolerance. It became evident that the innate immunity of the developing CL, oviduct, and uterus works together to provide optimal conditions for fertilization and early embryonic development during the first 7 days post-insemination.

Immunological microenvironment alterations in follicles of women with proven severe endometriosis undergoing in vitro fertilization

The purpose of this study was to test the hypothesis that different cytokine profiles may exist in the follicular fluid of endometriosis (EM) patients undergoing in vitro fertilization (IVF), as these differences may provide insights into the pathogenesis of the disease. This was a cross-sectional study conducted at the reproductive center of a medical university hospital. The study included 49 patients receiving IVF. 20 infertile women with proven EM and 29 women without diagnosed EM (control group) were evaluated. Follicular fluid (FF) and serum were collected at the time of follicle aspiration and the concentrations of 38 cytokines were determined by multiplexed immunoassay. The results indicated that the levels of IL-4, IL-13, IL-3 and IL-1α were significantly increased in the FF of women with EM, while levels of IFN-γ, IL-17A, MDC and MIP-1α were decreased compared with in the control subjects. In conclusions, the immune microenvironment of the FF in patients with EM is altered. This may contribute to the pathologic mechanism responsible for the poor outcome of IVF in patients with EM.

Ovarian stimulation does not influence the uterine immune environment in healthy infertile women

RESEARCH QUESTION

There is some controversy regarding the impact of ovarian stimulation on immune cells in women undergoing IVF. The study's aim was to determine whether ovarian stimulation affected immune uterine cells in healthy women undergoing IVF.

DESIGN

This prospective cohort study included 28 patients undergoing IVF and 47 healthy oocyte donors. Endometrial biopsies were taken in a natural cycle and after ovarian stimulation. All participants had a normal karyotype, pelvic ultrasound and cervical cytology results and thyroid-stimulating hormone concentration, as well as normal glucose and insulin concentrations and inherited and acquired thrombophilia test results. Screening tests including human papillomavirus were normal. Immune cells were analysed using three techniques: fluorescence-activated cell sorting, immunohistochemistry and gene expression. A human leukocyte antigen (HLA)-C tetramer was used as an 'artificial embryo'. The expression of genes including those for tumour necrosis factor (TNF)-α and interleukin-10 (IL-10) was analysed.

RESULTS

A comparison was made of the percentage and gene expression of CD56^brightCD16^- uterine natural killer (uNK), CD56^dimCD16⁺ natural killer cells, CD56^-CD16⁺ natural killer cells and TregCD25⁺CD4⁺FoxP3⁺ cells, uNK binding to the HLA-C tetramer, and TNF-α and IL-10 expression. No between- or within-group differences were observed in natural versus ovarian stimulation cycles.

CONCLUSIONS

Ovarian stimulation does not affect the uterine immune cell population or HLA-C binding in healthy women undergoing ovarian stimulation. Further studies are underway to find out if different responses might be seen in women with previous autoimmune disorders.

Effect of exogenous gonadotropin on the transcriptome of human granulosa cells and follicular fluid hormone profiles

BACKGROUND

Superovulation treatment had some adverse effects on maturity and development of oocytes. Can superovulation dose of gonadotropins (Gns) affect the transcriptome of granulosa cells and follicular fluid (FF) hormone levels?

METHODS

One leading pre-ovulatory follicle per subject was used from three natural-cycle and four Gn-stimulated patients. Granulosa cells and FF samples were collected from the same leading follicle of each patient. RNA was extracted from granulosa cells and subjected to deep sequencing and analysis. Follicle-stimulating hormone (FSH), estradiol (E2), androstenedione (AND), testosterone (T), luteinizing hormone (LH), and progesterone (P4) levels in FF were measured by immunoassays. Student's t test was used for statistical analysis.

RESULTS

A total of 715 genes were up-regulated, and 287 genes were down-regulated, in the Gn-stimulated group relative to the control group. Gene Ontology analysis revealed that the down-regulated genes were enriched in cell cycle and meiosis pathways, primarily those associated with follicle or oocyte maturation and quality. On the other hand, the up-regulated genes were enriched in functions related to immunity and cytokine-cytokine receptor interactions. Compared to the follicles of natural cycle, the E2 and LH concentrations were significantly reduced (P < 0.001), the P4 concentration was significantly increased (P = 0.003), and the concentrations of FSH, T and AND had no difference in the follicles of Gn-stimulated cycle.

CONCLUSIONS

Cell cycle- and meiosis-associated genes were down-regulated by Gns stimulation, whereas immune- and cytokine-associated genes were up-regulated. Hormone levels were also affected by Gns stimulation. Compared with natural-cycle follicles,putative markers associated with oocyte quality and follicle maturation were significantly different from those in Gn-stimulated follicles. Hormone levels in follicles were compatible with the steroidogenic patterns of granulosa cell, which reflects the follicle maturation and oocyte quality.

Ovarian and endometrial immunity during the ovarian cycle

Immune tolerance is crucial for the successful pregnancy, while immune effectors and their products are required to safeguard a fetus from the infectious pathogens. The key immune effectors, such as T, B, and natural killer (NK) cells, monocytes, macrophages, and dendritic cells take part in regulating the immune responses at the maternal-fetal interface. The immune effectors become involved in intraovarian reproductive processes as well, such as ovulation, production of corpus luteum (CL) and its degeneration and determine the quality and evolution of the oocyte during the folliculogenesis. In the cycling endometrium, NK cells are rapidly infiltrated into the endometrium after ovulation and participate in angiogenesis and spiral artery remodeling process. In this study, we reviewed the characteristics and action mechanisms of immune effectors and their products in the peripheral blood, ovary, and endometrium during the ovarian cycle, since a comprehensive understanding of immune responses during the ovarian cycle and the time of implantation can help us to predict the pregnancy outcome and take effective measures for the prevention of potential obstetrical complications.

Analysis of Protein Oxidative Modifications in Follicular Fluid from Fertile Women: Natural Versus Stimulated Cycles

Oxidative stress is associated with obstetric complications during ovarian hyperstimulation in women undergoing in vitro fertilization. The follicular fluid contains high levels of proteins, which are the main targets of free radicals. The aim of this work was to determine specific biomarkers of non-enzymatic oxidative modifications of proteins from follicular fluid in vivo, and the effect of ovarian stimulation with gonadotropins on these biomarkers. For this purpose, 27 fertile women underwent both a natural and a stimulated cycle. The biomarkers, glutamic semialdehyde (GSA), aminoadipic semialdehyde (AASA), N^ε-(carboxymethyl)lysine (CML), and N^ε-(carboxyethyl)lysine (CEL), were measured by gas-liquid chromatography coupled to mass spectrometry. Results showed that follicular fluid contained products of protein modifications by direct metal-catalyzed oxidation (GSA and AASA), glycoxidation (CML and CEL), and lipoxidation (CML). GSA was the most abundant biomarker (91.5%). The levels of CML amounted to 6% of the total lesions and were higher than AASA (1.3%) and CEL (1.2%). In the natural cycle, CEL was significantly lower (p < 0.05) than in the stimulated cycle, suggesting that natural cycles are more protected against protein glycoxidation. These findings are the basis for further research to elucidate the possible relevance of this follicular biomarker of advanced glycation end product in fertility programs.

The Effect of Supraphysiological Estradiol on Pregnancy Outcomes Differs Between Women With PCOS and Ovulatory Women

CONTEXT

Supraphysiological estradiol exposure after ovarian stimulation may disrupt embryo implantation after fresh embryo transfer. Women with polycystic ovary syndrome (PCOS), who usually overrespond to ovarian stimulation, have a better live birth rate after frozen embryo transfer (FET) than after fresh embryo transfer; however, ovulatory women do not.

OBJECTIVE

To evaluate whether the discrepancy in live birth rate after fresh embryo transfer vs FET between these two populations is due to the variation in ovarian response (i.e., peak estradiol level or oocyte number).

DESIGN, SETTING, PATIENTS, INTERVENTION(S), AND MAIN OUTCOME MEASURE(S)

This was a secondary analysis of data from two multicenter randomized trials with similar study designs. A total of 1508 women with PCOS and 2157 ovulatory women were randomly assigned to undergo fresh or FET. The primary outcome was live birth.

RESULTS

Compared with fresh embryo transfer, FET resulted in a higher live birth rate (51.9% vs 40.7%; OR, 1.57; 95% CI, 1.22 to 2.03) in PCOS women with peak estradiol level >3000pg/mL but not in those with estradiol level ≤3000 pg/mL. In women with PCOS who have ≥16 oocytes, FET yielded a higher live birth rate (54.8% vs 42.1%; OR, 1.67; 95% CI, 1.20 to 2.31), but this was not seen in those with <16 oocytes. In ovulatory women, pregnancy outcomes were similar after fresh embryo transfer and FET in all subgroups.

CONCLUSIONS

Supraphysiological estradiol after ovarian stimulation may adversely affect pregnancy outcomes in women with PCOS but not in ovulatory women.

Follicular fluid vascular endothelial growth factor is associated with type of infertility and interferon alpha correlates with endometrial thickness in natural cycle in vitro fertilization

The aim of this study was to analyse the presence of vascular endothelial growth factor (VEGF) and interferon alpha (IFN-α) in the follicular fluid (FF) and their possible influence, as pro-angiogenic or anti-angiogenic factors, on in vitro fertilization outcome. The concentrations of VEGF and IFN-α were correlated with oocyte and embryo quality, concentrations of hormones in the serum, perifollicular blood flow and endometrial thickness. VEGF was detected in all FF samples (median 706.6 pg/ml, range 182.9-6638 pg/ml). IFN-α was detected in 60% of the samples (median 6.5 pg/ml, range 0-79.4 pg/ml), while in 40% of the samples its levels were below the test detection limit. VEGF and IFN-α concentrations did not correlate with the cause of infertility, concentrations of FSH, LH, E2 and prolactin, oocyte or embryo quality. Significantly higher concentrations of VEGF have been found in women with primary compared with secondary infertility (p = 0.011, Mann Whitney test). The concentrations of VEGF and IFN-α did not correlate with the resistance index (RI) on days of hCG administration, follicular aspiration and embryo transfer. However, the concentrations of IFN-α correlated with endometrial thickness on the day of embryo transfer (Spearman correlation coefficient ρ = 0.4107; P < 0.05) but not on days of hCG administration and follicular aspiration. The mechanism of VEGF association with the previous ability of having a child needs to be clarified in future studies. The results of this study indicate a possible role of IFN-α in pathways of endometrial remodelling.