Evaluation of the relationship between follicular fluid oxidative stress, ovarian hormones, and response to gonadotropin stimulation

Metabolic profile and gene expression pattern of cytokines and antioxidants markers during different physiological stages in Barki ewes

BACKGROUND

In livestock, identifying the physiological and reproductive stages is valuable in guiding management decisions related to nutrition, veterinary procedures, and breeding programs. To achieve this goal, a cohort of Barki ewes in this research underwent observation across three pivotal physiological conditions: pre-pregnancy, late pregnancy, and early lactation. Blood samples were collected to investigate the changes in serum metabolic profile as well as gene expression pattern of cytokines and antioxidants markers during these stages.

RESULTS

Our results showed that during late pregnancy, there was a significant (P < 0.05) increase in red blood cells (11.9 ± 0.5 1012/L), hemoglobin (10.8 ± 0.4 g/dl) and neutrophils count (7 ± 0.1 109/L) with significant decrease (P < 0.05) of total white blood cell count (9.1 ± 0.05 109/L). The packed cell volume (%) and monocyte count showed a significant (P < 0.05) decrease during both late pregnancy and early lactation stages. The serum concentrations of glucose, cholesterol, GSH, GPx, SOD and catalase displayed significant (P < 0.05) decrease during late pregnancy and early-lactation. Notably, during late pregnancy, there was a significant (P < 0.05) increase in the serum concentrations of albumin, globulin, urea, IGF-1, and malondialdehyde with significant decrease (P < 0.05) of total protein (4.9 ± 0.08 g/dl). Additionally, during early lactation, there was a significant (P < 0.05) increase in the serum levels of non-esterified fatty acids, triiodothyronine (T3), and thyroxin (T4). The gene expression profiles of cytokines (IL-4, IL-6, IL-8, and NFKB) were decreased in the ewes during late pregnancy compared to pre-pregnant and early lactation stages. In addition, the expression profile of antioxidant genes (SOD, CAT, GPX, and Nrf2) was significantly upsurged in the non-pregnant ewes compared to late pregnancy and early lactation ones.

CONCLUSIONS

The results concluded that different physiological status significantly affects the blood metabolic profile and gene expression pattern in Barki sheep. Our findings can be helpful in monitoring animal health and applying in breeding programs of Barki sheep under harsh environmental conditions.

Different doses of recombinant FSH and determining parameters of oxidative stress

Background

This study aimed to examine if there is a connection between recombinant FSH dose and OS parameters in serum and the impact on IVF outcome.

Methods

This study consisted of 101 participants that went through IVF procedures. Parameter that were tested are SOD, SH groups and MDA. Serum samples were drawn before stimulation and on the last day of ovarian stimulation.

Results

Two groups were formed according to the dose of gonadotropins (rFSH). In both groups there were no significant differences in live-birth rate and miscarriage. In both groups mean serum MDA and SH-groups were significantly higher after ovarian stimulation, but mean serum SOD was significantly lower when compared to values before stimulation. There were less patients without OS before stimulation.

Conclusions

Our results suggest that there is a difference in serum concentration in groups SOD, SH groups and MDA at the beginning and at the end ovarian stimulation. On the other hand, dose of rFSH is not related with change of parameters for oxidative stress, quality of oocytes, embryos, fertilization, pregnancies, and miscarriage rate. Patients without oxidative stress before the IVF procedure needed lower doses of gonadotropins during stimulation.

Altered Energy Metabolism, Mitochondrial Dysfunction, and Redox Imbalance Influencing Reproductive Performance in Granulosa Cells and Oocyte During Aging

Female fertility decreases during aging. The development of effective therapeutic strategies to address the age-related decline in oocyte quality and quantity and its accurate diagnosis remain major challenges. In this review, we summarize our current understanding of the study of aging and infertility, focusing primarily on the molecular basis of energy metabolism, mitochondrial function, and redox homeostasis in granulosa cells and oocytes, and discuss perspectives on future research directions. Mitochondria serve as a central hub sensing a multitude of physiological processes, including energy production, cellular redox homeostasis, aging, and senescence. Young granulosa cells favor glycolysis and actively produce pyruvate, NADPH, and other metabolites. Oocytes rely on oxidative phosphorylation fueled by nutrients, metabolites, and antioxidants provided by the adjacent granulosa cells. A reduced cellular energy metabolism phenotype, including both aerobic glycolysis and mitochondrial respiration, is characteristic of older female granulosa cells compared with younger female granulosa cells. Aged oocytes become more susceptible to oxidative damage to cells and mitochondria because of further depletion of antioxidant-dependent ROS scavenging systems. Molecular perturbations of gene expression caused by a subtle change in the follicular fluid microenvironment adversely affect energy metabolism and mitochondrial dynamics in granulosa cells and oocytes, further causing redox imbalance and accelerating aging and senescence. Furthermore, recent advances in technology are beginning to identify biofluid molecular markers that may influence follicular development and oocyte quality. Accumulating evidence suggests that redox imbalance caused by abnormal energy metabolism and/or mitochondrial dysfunction is closely linked to the pathophysiology of age-related subfertility.

The Impact of Follicular Fluid Oxidative Stress Levels on the Outcomes of Assisted Reproductive Therapy

Oocyte quality is a pivotal determinant of assisted reproductive outcomes. The quality of oocytes is intricately linked to their developmental microenvironment, particularly the levels of oxidative stress within the follicular fluid. Oxidative stress levels in follicular fluid may have a substantial influence on oocyte health, thereby impacting the outcomes of ART procedures. This review meticulously explores the intricate relationship between oxidative stress in follicular fluid and ART outcomes. Furthermore, it delves into strategies aimed at ameliorating the oxidative stress status of follicular fluid, with the overarching goal of enhancing the overall efficacy of ART. This research endeavors to establish a robust foundation and provide valuable guidance for clinical treatment approaches, particularly in the context of infertile women, including those of advanced maternal age.

The Role of Oxidative Stress in Infertility

(1) Background: Oxidative stress markers in the follicular fluid and serum of the patient with IVF results (number of fertilized oocytes, number of embryos, cumulative pregnancy rate) are important in establishing the causes of infertility. (2) Methods: 42 patients were enrolled in the study over the duration of 24 months and were divided into two groups: the study group divided into the female etiology for infertility as a tubal factor, diminished ovarian reserve, endometriosis, and unexplained infertility, and the control group consisting of the male factor, excluding the sperm donors and with no female factor cause. On the day of ovarian puncture in IVF, follicular fluid and serum were collected from the patients. (3) Results: Malondialdehyde from the follicular fluid was higher in the control group. The total antioxidant capacity in the follicular fluid is positively correlated with the pregnancy rate. There is no statistically significant difference in the oxidative stress markers from serum in both groups. (4) Conclusions: The capacity of the follicular fluid environment to contain the reactive oxygen species (ROS) leads to a higher pregnancy rate in the control group.

Unraveling female reproductive senescence to enhance healthy longevity

In a society where women often want successful careers and equal opportunities to men, the early nature of ovarian aging often forces women to make difficult life choices between career and family development. Fertility in women begins to decline after the age of 37 years and it is rare for pregnancies to occur after 45. This reproductive decline in women is inevitable and culminates in menopause, which is a major driver of age-related diseases. In a world where biomedical advances are leading to modifiable biological outcomes, it is time to focus on mitigating female reproductive senescence to maintain fertility and preserve age-related hormonal functions, with the goal of providing increased life choices and enhancing healthspan. To date, reproductive longevity research remains an understudied field. More needs to be done to unravel the biology of the ovarian follicles, which are the functional units of reproductive lifespan and are comprised of cell types including the oocyte (female gamete) and a group of specialized supporting somatic cells. Biological attempts to maintain the quality and quantity of follicles in animal models through manipulating pathways involved in aging can potentially prolong female reproductive lifespan and healthspan. Here, we summarize the molecular events driving ovarian aging and menopause and the interventional strategies to offset these events. Developing solutions to female reproductive senescence will open doors to discover ways to enhance true healthy longevity for both men and women.

Hormone concentrations of dominant follicles in the TALES randomized controlled trial comparing letrozole with tamoxifen

BACKGROUND

In this secondary analysis of the TAmoxifen or Letrozole in Estrogen Sensitive tumors (TALES) trial, we aimed to investigate if concurrent administration of letrozole vs. tamoxifen vs. no added treatment affects hormonal composition and size of stimulated ovarian follicles.

METHODS

TALES is a randomized controlled trial of IVF stimulation for estrogen receptor (ER)-positive breast cancer patients stimulated with gonadotropins and administered concurrent tamoxifen 20 mg or letrozole 5 mg. We analyzed estradiol (E2), testosterone (T), progesterone (P4), follicle stimulating hormone (FSH), luteinizing hormone (LH), and anti-Mullerian hormone (AMH). We used ANOVA/Kruskal-Wallis, logistic, and linear regression models to examine differences in follicular hormone levels, size, and mature oocyte yield between trial arm.

RESULTS

We included data from total 246 follicles (94 letrozole, 82 tamoxifen, and 70 control) from 123 unique participants. E2 was lower (letrozole 187.4, tamoxifen 1026.0, control 821.5 ng/mL, p < 0.01) and T was higher (letrozole 2489, tamoxifen 571, and control 504 ng/mL, p < 0.03) in the letrozole group compared to tamoxifen and control groups, while other hormone levels and follicle size were similar across groups. There were no significant differences in hormone concentrations within the follicle between tamoxifen and control arms. On multivariate logistic regression, there was no significant association of mature oocyte yield by follicle size, hormone levels, or trial arm.

CONCLUSIONS

Concurrent administration of letrozole with gonadotropins affects follicular E2 and T concentrations compared to tamoxifen/control. Tamoxifen was not associated with any differences in hormone concentrations within the follicle. Mature oocyte yield was similar across groups.

RNA binding protein IGF2BP1 meditates oxidative stress-induced granulosa cell dysfunction by regulating MDM2 mRNA stability in an m6A-dependent manner

Both genetic and microenvironmental detrimental factors are involved in ovarian dysfunction, leading to the increasing rate of involuntary childlessness in recent years. Oxidative stress (OS), which is characterized by the imbalance of redox system with redundant reactive oxygen species (ROS) overwhelming the antioxidant defense, is regarded as one of the culprits of ovarian dysfunction. OS causes damage to various types of ovarian cells including granulosa cells (GCs), jeopardizing the ovarian microenvironment, disturbing follicular development and participating in various female reproductive disorders. However, the specific molecular pathological mechanisms underlying this process have not been fully elucidated. In this study, we found that 3-nitropropionic acid (3-NP) treatment led to significant IGF2BP1 downregulation via, at least partially, inducing ROS overproduction. IGF2BP1 regulates GCs viability, proliferation, cell cycle and cellular senescence by enhancing MDM2 mRNA stability in an m6A-dependant manner. IGF2BP1 overexpression partially rescued 3-NP induced GCs damages, while ectopically expressed MDM2 alleviated both 3-NP or IGF2BP1-knockdown induced GCs dysfunction. These results reveal an epigenetic molecular mechanism underlying OS-related GCs disorders, which may help to establish a novel potential clinical marker for predicting the GCs status as well as the follicular developmental potential.

Metformin promotes in vitro maturation of oocytes from aged mice by attenuating mitochondrial oxidative stress via SIRT3-dependent SOD2ac

Human female fecundity decreases irreversibly as chronological age rises, adversely affecting oocyte quality, consequently worsening pregnancy outcomes and increasing the extent of birth defects. The first-line type 2 diabetes treatment metformin has been associated with delayed aging and reduction of oxidative stress; yet it remains unclear if metformin confers any benefits for oocytes from aged mice, particularly in the context of the assisted human reproductive technology (ART) known as in vitro maturation (IVM). Here, we found that adding metformin into the M16 culture medium of oocytes from aged mice significantly improved both oocyte maturation and early embryonic development. This study showed that metformin reduced the extent of meiotic defects and maintained a normal distribution of cortical granules (CGs). RNA-seq analysis of metformin-treated oocytes revealed genes apparently involved in the reduction of mitochondrial ROS. Further, the results supported that the metformin improved mitochondrial function, reduced apoptosis, increased the extent of autophagy, and reduced mitochondrial ROS via SIRT3-mediated acetylation status of SOD2K68 in oocytes from aged mice. Thus, this finding demonstrated a protective effect for metformin against the decreased quality of oocytes from aged mice to potentially improve ART success rates and illustrated a potential strategy to prevent or delay reproductive aging.

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

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

Effect of hypothyroidism and thyroid autoimmunity on the ovarian reserve: A systematic review and meta-analysis

Background

Evidence suggests that hypothyroidism and thyroid autoimmunity (TAI) are possibly associated with ovarian dysfunction. This meta‐analysis aimed to investigate whether hypothyroidism and/or TAI affect the ovarian reserve and evaluated using the anti‐Mullerian hormone (AMH).

Methods

PubMed, EMBASE, Web of Science, and Cochrane Controlled Trials Register databases from inception to October 2020 were searched to identify relevant studies. Studies comparing the AMH levels between the control and the affected groups were included in the data synthesis. The primary endpoint in the meta‐analysis was AMH levels compared with the controls.

Main findings

Nine trials were included in the analysis. The AMH levels were significantly lower in the adults with euthyroid TAI (mean difference −0.12, [95% CI: −0.18 to −0.06]). The AMH levels tended to be lower in subclinical hypothyroidism and overt hypothyroidism than in the control group, although the differences were not significant. The AMH levels were significantly higher in the euthyroid TAI group in the adolescents (mean difference 2.51, [95% CI 1.82 to 3.21]).

Conclusion

TAI and hypothyroidism may affect the ovarian reserve. The opposite effects on AMH levels depending on age suggest that TAI may be implicated in the depletion of follicles in adults following extensive activation of primordial follicles in adolescence.

The role of oxidant status on the etiopathogenesis of unexplained infertility and intracytoplasmic sperm injection - embryo transfer success: a case-control study

The present study aims to evaluate the role of follicular fluid (FF) and serum (s) total oxidant status (TOS), total antioxidant status (TAS) and oxidative stress index (OSI) on the etiopathogenesis of unexplained infertility (UI) and intracytoplasmic sperm injection-embryo transfer (ICSI-ET) success. Twenty UI patients and 20 controls with male factor undergoing an ICSI-ET cycle were recruited. FF samples aspirated from mature follicles and blood samples collected just before the oocyte retrieval were stored until analysis. Embriyo quality and implantation, clinical pregnancy and living birth rates were evaluated.FF-TOS and FF-OSI of the UI patients were higher than the control group. s-TOS and s-OSI were significantly increased in the UI group compared to the control group. However, only s-TOS was positively associated with UI diagnosis after age-adjustment. FF-OSI was negatively associated with embryo quality in the UI group (but not in the whole group) after age-adjustment. No significant effect of TAS, TOS, and OSI on implantation, clinical pregnancy and live birth rate was observed. In conclusion, especially s-TOS can have a partial role in the etiopathogenesis of UI. High FF-OSI can decrease the quality of embryo in patients with UI.Impact statementWhat is already known? Total oxidant status (TOS), total antioxidant status (TAS), and oxidative stress index (OSI), which is the ratio of TOS to TAS, provide a broad overview of redox status.What do the results of this study add? An elevated serum TOS (s-TOS) was associated with UI after age-adjustment. Follicular fluid OSI (FF-OSI) was negatively associated with embryo quality and embryo score in the UI group (but not in the whole group) after age-adjustment. No significant effect of TAS, TOS, and OSI was observed on implantation, clinical pregnancy, and live birth rate.What are the implications of these findings for clinical practice and/or further research? Evaluation of FF-OSI in women with unexplained infertility can be considered to predict embryo quality. Further studies that evaluate antioxidant agents to decrease oxidative stress in UI and its' clinical implications are warranted.

Altered redox status may contribute to aberrant folliculogenesis and poor reproductive outcomes in women with polycystic ovary syndrome

BACKGROUND

Women with polycystic ovary syndrome (PCOS) are often infertile and opt for artificial reproductive techniques (ART) to conceive. Disrupted pro-/antioxidant balance in oocyte microenvironment may contribute towards sub-optimal oocyte/embryo quality and poor ART outcome in them.

METHODS

Activities/levels of redox markers and their transcript expression were investigated in follicular fluid and granulosa cells respectively, in women with PCOS (n = 71) and controls (n = 50) undergoing in vitro fertilization (IVF). Correlation analysis of redox markers and IVF parameters was performed.

RESULTS

Activities of superoxide dismutase, glutathione reductase, glutathione peroxidase, and paraoxonase1 were significantly lower in follicular fluid of PCOS women than in controls. Levels of lipid peroxidation, oxidative protein modification, and oxidized glutathione were higher, whereas those of total antioxidant capacity, total thiols, and reduced glutathione were lower in follicular fluid of PCOS women than in controls. Further, comparison of redox markers based on insulin resistance and BMI status of study participants showed similar trends, indicating that PCOS pathophysiology is a significant contributor to oxidative stress irrespective of insulin resistance and BMI. Transcript levels of antioxidant enzymes were lower in granulosa cells from PCOS women than in controls, and they accorded with their activities in follicular fluid. Moreover, few redox markers showed significant correlations with oocyte/embryo quality and pregnancy outcome.

CONCLUSION

Our data indicates disrupted redox homeostasis in follicular environment in PCOS which may negatively influence oocyte/embryo quality. Further, granulosa cells may play crucial role in maintaining follicular redox homeostasis. Glutathione system and paraoxonase1 could be explored further as surrogates for IVF prognosis/outcome.

Systematic Analysis of Long Noncoding RNA and mRNA in Granulosa Cells during the Hen Ovulatory Cycle

Simple Summary

Chicken is one of the most economically important farm poultry, and providing many food products, such as meat and eggs for human consumption. However, follicle transcriptome studies in chickens with timepoints relating to changes in luteinizing hormone level remain unknown. In this study, the largest preovulatory follicle of chicken underwent the early, middle, and terminal stages of ovulatory cycle. Our work provides a comprehensive analysis of lncRNAs and mRNAs in chicken granulosa cells during the ovulatory cycle. A total of 12,479 mRNAs and 7528 lncRNAs were identified among the three stages. Thousands of lncRNAs were annotated, and the most differentially abundant genes were detected in the luteinizing hormone surge stage. Functional features of the lncRNAs and mRNAs at each stage were revealed, which was also associated with the changes in serum luteinizing hormone level. Especially, genes related to oxidative stress, steroids regulation, and inflammatory process were enriched in the luteinizing hormone surge stage, The comprehensive data generated in this study provides the foundation for future investigations to improve the reproductive performance of chickens and explore the mechanisms responsible for female ovarian diseases.

Abstract

Long non-coding RNAs (lncRNAs) and mRNAs are temporally expressed during chicken follicle development. However, follicle transcriptome studies in chickens with timepoints relating to changes in luteinizing hormone (LH) levels are rare. In this study, gene expression in Rohman layers was investigated at three distinct stages of the ovulatory cycle: zeitgeber time 0 (ZT0, 9:00 a.m.), zeitgeber time 12 (ZT12, 9:00 p.m.), and zeitgeber time 20 (ZT20, 5:00 a.m.) representing the early, middle, and LH surge stages, respectively, of the ovulatory cycle. Gene expression profiles were explored during follicle development at ZT0, ZT12, and ZT20 using Ribo-Zero RNA sequencing. The three stages were separated into two major stages, including the pre-LH surge and the LH surge stages. A total of 12,479 mRNAs and 7528 lncRNAs were identified among the three stages, and 4531, 523 differentially expressed genes (DEGs) and 2367, 211 differentially expressed lncRNAs (DELs) were identified in the ZT20 vs. ZT12, and ZT12 vs. ZT0, comparisons. Functional enrichment analysis revealed that genes involved in cell proliferation and metabolism processes (lipid-related) were mainly enriched in the ZT0 and ZT12 stages, respectively, and genes related to oxidative stress, steroids regulation, and inflammatory process were enriched in the ZT20 stage. These findings provide the basis for further investigation of the specific genetic and molecular functions of follicle development in chickens.

Novel therapeutic targets to improve IVF outcomes in endometriosis patients: a review and future prospects

BACKGROUND

Patients with endometriosis often experience infertility and have poor IVF outcomes, with low fertilization and pregnancy rates. Although many theories have tried to explain the mechanisms underlying infertility in these patients, none of them is conclusive.

OBJECTIVE AND RATIONALE

In this review, we discuss the pathologic mechanisms through which endometriosis likely leads to infertility along with the therapeutic options used to date to treat endometriosis-related infertility and, thereby, to improve IVF outcomes in patients with endometriosis.

SEARCH METHODS

We performed a comprehensive literature search of clinical outcomes in endometriosis and the molecular mechanisms contributing to oocyte quality using the PubMed database to identify human and animal studies published from 1992 until September 2020. In total, 123 manuscripts were included.

OUTCOMES

While some theories propose that endometriosis patients may have fertility problems as a result of decreased endometrial receptivity, others reinforce the idea that infertility could be associated with oocyte alterations and lower implantation rates. Single-cell RNA sequencing of oocytes from patients with endometriosis has identified dysregulated mechanisms involved in steroid metabolism and biosynthesis, response to oxidative stress and cell cycle regulation. Dysregulation of these mechanisms could result in the poor IVF outcomes observed in patients with endometriosis. Further, impaired steroidogenesis may directly affect oocyte and embryo quality. Increased oxidative stress in patients with endometriosis also has a detrimental effect on the follicular microenvironment, inducing cell cycle dysregulation in oocytes, poor oocyte quality, and infertility. Moreover, granulosa cells in the context of endometriosis undergo increased apoptosis and have an altered cell cycle that could adversely affect folliculogenesis, oocyte and embryo quality, and IVF outcomes. Endometriosis is also associated with inflammatory damage and impaired angiogenesis, which could be directly correlated with poor IVF outcomes. While therapeutic options using GnRH analogues, progestins and aromatase inhibitors do not improve endometriosis-related infertility, anti-inflammatory agents and antioxidant supplementation could improve oocyte quality as well as implantation and clinical pregnancy rates in patients with endometriosis.

WIDER IMPLICATIONS

Endometriosis is a heterogeneous disease whose pathogenesis is complex and could affect fertility by altering a collection of molecular mechanisms in oocytes. Thus, a single model is not sufficient to describe endometriosis-related infertility. Dysregulation of steroidogenesis, oxidative stress, cell cycle progression, inflammation and angiogenesis in the follicular environment and oocytes in individuals with endometriosis are all possible contributors to endometriosis-related infertility. Therefore, treatments targeting these mechanisms could be therapeutic alternatives to improve IVF outcomes for these patients.

Adaptive and Biological Responses of Buffalo Granulosa Cells Exposed to Heat Stress under In Vitro Condition

Simple Summary

The pertinent consequences of global warming substantially affect both animal productivity and fertility. Noteworthy, tropical and subtropical animal breeds are productively suited to hot climate conditions. Therefore studying the physiological changes accompanying high temperature, especially in tropically adapted species such as buffalo, will help in understanding the mechanisms that the animal use to accomplish the necessary functions efficiently. Concerning fertility-related activity, granulosa cells are important for the regulation of ovarian function and the completion of oocyte maturation. In this study, the buffalo granulosa cells were examined for their viability, physiological and molecular responses under in vitro heat stress conditions. Buffalo granulosa cells displayed different adaptive responses, at the physiological and molecular levels, to the different heat stress conditions. At 40.5 °C, granulosa cells exhibited a functional persistence compared to the control and other heat-treated groups. These results will provide insights into ways that tropically adapted breeds may be able to maintain better reproductive function when exposed to heat stress compared to temperate breeds.

Abstract

The steroidogenesis capacity and adaptive response of follicular granulosa cells (GCs) to heat stress were assessed together with the underlying regulating molecular mechanisms in Egyptian buffalo. In vitro cultured GCs were exposed to heat stress treatments at 39.5, 40.5, or 41.5 °C for the final 24 h of the culture period (7 days), while the control group was kept under normal conditions (37 °C). Comparable viability was observed between the control and heat-treated GCs at 39.5 and 40.5 °C. A higher release of E2, P4 and IGF-1 was observed in the 40.5 °C group compared with the 39.5 or 41.5 °C groups. The total antioxidant capacity was higher in response to heat stress at 39.5 °C. At 40.5 °C, a significant upregulation pattern was found in the expression of the stress resistance transcripts (SOD2 and NFE2L2) and of CPT2. The relative abundance of ATP5F1A was significantly downregulated for all heat-treated groups compared to the control, while TNFα was downregulated in GCs at 39.5 °C. Expression analyses of stress-related miRNAs (miR-1246, miR-181a and miR-27b) exhibited a significant downregulation in the 40.5 °C group compared to the control, whereas miR-708 was upregulated in the 39.5 and 40.5 °C groups. In conclusion, buffalo GCs exhibited different adaptive responses, to the different heat stress conditions. The integration mechanism between the molecular and secretory actions of the GCs cultured at 40.5 °C might provide possible insights into the biological mechanism through which buffalo GCs react to heat stress.

Altered transcriptome in cumulus cells of infertile women with advanced endometriosis with and without endometrioma

RESEARCH QUESTION

Is the transcriptome of cumulus cells of infertile women with advanced endometriosis (EIII/IV), with and without endometrioma, altered?

DESIGN

In this prospective case-control study, next-generation RNA sequencing was used to compare the transcript profile of cumulus cells among infertile patients undergoing ovarian stimulation for intracytoplasmic sperm injection with EIII/IV, with (n = 9) and without endometrioma (n = 9), and controls (n = 9). An in-silico enrichment analysis was conducted to establish the possibly altered pathways in cumulus cells of patients with endometriosis.

RESULTS

Most of the differentially expressed genes (DEG) were found when cumulus cells from women with EIII/IV with endometrioma were compared with controls (DEG, n = 461). In women with EIII/IV without endometrioma, only 66 DEG were verified compared with controls. The enrichment analysis showed that some DEG in cumulus cells of endometriosis are involved in important pathways for the oocyte competence acquisition, such as oxidative phosphorylation, metabolism, mitochondrial function, acetylation and steroid biosynthesis. No DEG were found when cumulus cells from women with EIII/IV with and without endometrioma were compared.

CONCLUSION

RNA sequencing results suggest that cumulus cells of infertile women with EIII/IV have an altered transcriptome, regardless of endometrioma. The present findings offer a better understanding of the genes and molecular mechanisms that may be involved in endometriosis-related infertility, mostly in the oocyte competence acquisition process.

Factors related to follicular oxidative stress in intracytoplasmic sperm injection cycles and its effects on granulosa cells

The aim of the present study was to investigate several common conditions that may potentially be correlated with follicular oxidative status during an intracytoplasmic sperm injection (ICSI) cycle and that include the serum oestrogen level on the day of oocyte pick-up, maternal age and pregnancy outcome. Patients that were enrolled in the study were classified randomly into three groups using their numerical order. The first group were classified based on maternal age (<35 and ≥35 years) (n = 398), the second group on the serum oestradiol (E2) level on the day of human chorionic gonadotropin (hCG) administration (levels >90th percentile and ≤ 90th percentile) (n = 491) and the third group on pregnancy outcome (positive/negative) (n = 376). The groups were matched for the other variables (stimulation protocol, dose of gonadotropin, duration of stimulation, antral follicle count, body mass index, basal follicle stimulating hormone (FSH), and E2 levels and day of hCG trigger) to prevent the possible contribution of those parameters to the results. Each group was matched for other variables (stimulation protocol, dose of gonadotrophin, duration of stimulation, antral follicle count, body mass index, basal FSH and E2 levels and day of hCG trigger) that may have affected the outcome, except for the parameter under investigation. Maternal age (P = 0.044,168 r = 0.418), oestrogen level on day of hCG administration (P = 0.001, r = 0.436) and pregnancy outcome (AUC = 0.65, P = 0.071) were found to be correlated with follicular oxidative status. The results obtained will help us to shield patients from possible situations that may cause oxidative stress and therefore adverse outcomes of an ICSI cycle.

Characterization of the Age-Dependent Changes in Antioxidant Defenses and Protein's Sulfhydryl/Carbonyl Stress in Human Follicular Fluid

The oxidative stress, characterized by the imbalance between pro-oxidants and antioxidants molecules, seems to be involved in the pathogenesis of female subfertility. In particular, the presence of different markers of oxidative stress has been reported in human follicular fluid (FF) surrounding oocytes. Based on its distinctive composition and on the close proximity to the oocyte, FF creates a unique microenvironment having a direct impact on oocyte quality, implantation, and early embryo development. An imbalance in reactive oxygen species (ROS) production in ovarian follicular fluid may have a negative effect on these processes and, as a consequence, on female fertility. Therefore, the aim of this study was to evaluate the redox state of the FF through various methodological approaches. By means of 2D-electrophoresis we demonstrated that the main structural changes occurring in the proteins of the follicular fluid of normovulatory women were correlated to the age of the patients and to the antioxidant defenses present in the FF. Measurement of these parameters could have clinical relevance, since the assessment of the oxidative stress rate may be helpful in evaluating in vitro fertilization potential.

Single-cell RNA sequencing of oocytes from ovarian endometriosis patients reveals a differential transcriptomic profile associated with lower quality

STUDY QUESTION

Do oocytes from women with ovarian endometriosis (OE) have a different transcriptomic profile than those from healthy women?

SUMMARY ANSWER

Oocytes from endometriosis patients, independently of whether they came from the affected ovary, exhibited a differential transcriptomic profile compared to oocytes from healthy egg donors.

WHAT IS KNOWN ALREADY

Studies of endometriosis have sought to determine whether OE affects oocyte quality. While many reports indicate that oocytes recovered from endometriotic ovaries may be affected by the disease, other studies have found no significant differences among oocyte/embryo quality and fertilization, implantation and pregnancy rates in women with endometriosis.

STUDY DESIGN, SIZE, DURATION

This prospective study compared metaphase II (MII) oocytes (n = 16) from endometriosis patients (n = 7) to oocytes (n = 16) from healthy egg donors (n = 5) by single-cell RNA sequencing (scRNA-seq). Participants were recruited between December 2016 and February 2018 at IVI-RMA Valencia and Vigo clinics.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human MII oocytes were collected from healthy egg donors and OE patients aged 18-34 years, with a body mass index of <30 and >6 pre-antral follicles. RNA was extracted, cDNA was generated and libraries were constructed and sequenced. scRNA-seq data libraries were processed and statistically analysed. Selected genes were validated by quantitative real-time PCR.

MAIN RESULTS AND THE ROLE OF CHANCE

Our scRNA-seq results revealed an effect of endometriosis on global transcriptome behaviour in oocytes from endometriotic ovaries. The highest number of differentially expressed genes (DEGs) was found when oocytes from women with OE were compared to oocytes from healthy donors [520 DEGs (394 upregulated and 126 downregulated)], independently of whether oocytes came from an affected or unaffected ovary. Among the top 20 significant DEGs in this comparison, most were upregulated, including APOE, DUSP1, G0S2, H2AFZ, ID4, MGST1 and WEE1. PXK was the only downregulated gene. Subsequently, functional analysis showed 31 enriched functions deregulated in endometriosis patients (Benjamini P < 0.1), being 16 significant enriched functions considering Benjamini P < 0.05, which involved in biological processes and molecular functions, such as steroid metabolism, response to oxidative stress and cell growth regulation. In addition, our functional analysis showed enrichment for mitochondria, which are an important cellular component in oocyte development. Other functions important in embryo development, such as angiogenesis and methylation, were also significantly enriched.

LARGE SCALE DATA

All raw sequencing data are submitted in Gene Expression Omnibus (GEO) under accession number (PRJNA514416).

LIMITATIONS, REASONS FOR CAUTION

This study was restricted only to OE and thereby other anatomical entities, such as peritoneal and deep infiltrating endometriosis, were not considered. This is a descriptive study with a limited number of samples reflecting the difficulty to recruit human oocytes, especially from women with endometriosis.

WIDER IMPLICATIONS OF THE FINDINGS

This study suggests that OE exhibits a global transcriptomic effect on oocytes of patients in OE, independently if they come from an affected or unaffected ovary and alters key biological processes and molecular functions related to steroid metabolism, response to oxidative stress and cell growth regulation, which reduce oocyte quality.

STUDY FUNDING/COMPETING INTEREST(S)

This research was supported by IVI Foundation, the Spanish Ministry of Economy and Competitiveness through the Miguel Servet programme (CPII018/00002 to F.D.), the Sara Borrell Program (CD15/00057 to H.F.) and the VALi+d Programe (Generalitat Valenciana); ACIF/2016/444 to A.C.). The authors have no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

None.

Effects o follicular fluid oxidative status on human mural granulosa cells, oocyte competency and ICSI parameters

PURPOSE

The aim of the present study was to understand the molecular and genetic alterations involved in follicular fluid oxidative process by investigating human mural granulosa cells and to find possible biomarkers for oocyte competency and ICSI outcome measures.

METHODS

A total of 166 patients were included in the study. Total antioxidant and oxidant levels of follicular fluids were measured on the day of oocyte pick-up and oxidative status were calculated. Expression profiles of three potential target proteins in cases of oxidative stress (Hsp70, Tgf-β, Notch1), DNA status and chromatin integrity of mural granulosa cells were analyzed.

RESULTS

TAS levels were positively correlated with the Hsp70 and Tgf-β expression patterns of mural granulosa cells. Mature oocyte rate and fertilization rates were affected negatively by the presence of oxidative stress and a significant positive correlation was found with the oxidative status and the fertilization rate, whereas no correlation with the remaining ICSI parameters in the overall group.

CONCLUSIONS

Oxidative stress detected in follicular fluid adversely affects fertilization rates post-ICSI however no effect on the remaining parameters including embryo quality, pregnancy, and implantation rates. DNA damage, chromatin integrity were increased, whereas Hsp70 and Tgf-ß were decreased in mural granulosa cells in cases of oxidative stress which may indirectly reflect the oocyte competency and may be used as biomarkers for ICSI outcome measures.

Tyrosine nitrations impaired intracellular trafficking of FSHR to the cell surface and FSH-induced Akt-FoxO3a signaling in human granulosa cells

Many infertile women suffered from poor ovarian response, and increased reactive oxygen species with age might mediate the poor ovarian response to FSH. In this study, we collected follicular fluids and isolated granulosa cells from female patients. Increased levels of peroxynitrite, tyrosine nitrations of FSH receptor (FSHR) and apoptosis were obviously detectable with decreased FSHR protein expressions in granulosa cells of the poor ovarian responders. In KGN (a human ovarian granulosa cell line) cells, exogenous peroxynitrite could sequester FSHR in the cytoplasm, and these dislocated FSHR might suffer from proteasome-mediated degradations. Here, we identified four peroxynitrite-mediated nitrated tyrosine residues of FSHR. Site-directed mutagenesis of FSHR revealed that Y626 was pivotal for intracellular trafficking of FSHR to the cell surface. Akt-induced inactivation of FoxO3a was required for the repression of FSH on granulosa cell apoptosis. However, peroxynitrite impaired FSH-induced Akt-FoxO3a signaling, while FSHR-Y626A mutant took similar effects. In addition, FoxO3a knockdown indeed impaired FSH-mediated cell survival, while FoxO3a-S253A mutant reversed that significantly.

Reduced ovarian response to controlled ovarian stimulation is associated with increased oxidative stress in the follicular environment

Serum estradiol (E2) level is routinely used to monitor the ovarian response during controlled ovarian hyperstimulation (COH) and the concentration of serum E2 may influence the oocyte quality and pregnancy outcome. However, the knowledge on the association between COH induced serum E2 level, oocyte quality and embryo development is limited. Therefore we investigated the association between serum E2 level, oxidative stress in the follicular fluid and granulosa cells (GCs) response to elucidate the association between E2 level and embryological outcome. In this study, patients (n = 30) undergoing ART were categorized as 'normal responders' (NR, n = 10), 'poor responders' (PR, n = 10) and hyper responders (HR, n = 10). The follicular fluid malondialdehyde (MDA) level was determined. The total RNA extracted from GCs was subjected to analyse the relative abundance of transcripts of stress response genes (P53, caspase 3,8-oxoguanine DNA glycosylase, OGG1 and heat shock protein 70; HSP70) and embryological outcome was noted. Follicular fluid MDA level was significantly higher in PR (p < 0.01) compared NR and HR whereas number of top-quality embryos were significantly lower in PR and HR compared to NR (p < 0.01). The relative expression of P53, HSP70, and OGG1 in GCs was significantly elevated in PR (p < 0.05-0.01). An inverse relationship was established between serum E2 level vs follicular MDA level (r = -0.45; p < 0.01) and follicular MDA level vs. number of top-quality embryos (r = -0.45; p < 0.01). Hence, patients with low serum E2 had elevated oxidative stress in their follicular environment and poor quality embryos implicating the risk of oxidative stress in patients with poor ovarian response.

Reactive oxygen species in reproduction: harmful, essential or both?

The process of embryonic development is crucial and radically influences preimplantation embryo competence. It involves oocyte maturation, fertilization, cell division and blastulation and is characterized by different key phases that have major influences on embryo quality. Each stage of the process of preimplantation embryonic development is led by important signalling pathways that include very many regulatory molecules, such as primary and secondary messengers. Many studies, both in vivo and in vitro, have shown the importance of the contribution of reactive oxygen species (ROS) as important second messengers in embryo development. ROS may originate from embryo metabolism and/or oocyte/embryo surroundings, and their effect on embryonic development is highly variable, depending on the needs of the embryo at each stage of development and on their environment (in vivo or under in vitro culture conditions). Other studies have also shown the deleterious effects of ROS in embryo development, when cellular tissue production overwhelms antioxidant production, leading to oxidative stress. This stress is known to be the cause of many cellular alterations, such as protein, lipid, and DNA damage. Considering that the same ROS level can have a deleterious effect on the fertilizing oocyte or embryo at certain stages, and a positive effect at another stage of the development process, further studies need to be carried out to determine the rate of ROS that benefits the embryo and from what rate it starts to be harmful, this measured at each key phase of embryonic development.

Curcumin-loaded super-paramagnetic iron oxide nanoparticle affects on apoptotic factors expression and histological changes in a prepubertal mouse model of polycystic ovary syndrome-induced by dehydroepiandrosterone - A molecular and stereological study

AIMS

This study investigated the effects of curcumin-loaded super-paramagnetic iron oxide (Fe₃O₄) nanoparticles (NPs) (SPIONs) on histological parameters and apoptosis-inducing factors (AIFs) in an experimental mouse model of polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

A total number of 40 female prepuberal BALB/c mice were randomly divided into four groups. Group 1 was selected as control and Group 2 was considered as a vehicle taking sesame oil, in the form of a curcumin carrier. Moreover, Group 3 was administered with dehydroepiandrosterone (DHEA) at 6 mg/100 g of the body weight and Group 4 received the DHEA plus the NPs of curcumin (5.4 mg/100 g) for twenty consecutive days. Finally, histology, stereology, and apoptosis of the ovary were evaluated.

KEY FINDINGS

The results revealed that the NPs of curcumin had reduced ovarian volume (p < 0.05) and a total number of primary, secondary, antral, and primordial follicles in comparison with the PCOS and vehicle groups (p < 0.05). Furthermore, curcumin treatment following administration of the DHEA resulted in a significant decrease in BAX (p < 0.001) and levels of expression of Caspase3 (CASP3) protein, increased levels of B-cell lymphoma 2 (Bcl2) expression (p < 0.05), and moderated apoptosis in granulosa cells in comparison with the ones seen in the PCOS group.

SIGNIFICANCE

Ovarian injuries and DHEA-induced apoptosis were efficiently suppressed by curcumin, indicating the probable protective property of NPs of curcumin against PCOS.

Follicular fat-soluble vitamins as markers of oocyte competency

The main aim of this prospective study was to investigate the effect of the concentration of fat-soluble vitamins A, D, E and K in individual follicles on oocyte quality and developmental competence. The analysis was performed on 313 follicular fluid (FF) samples from 50 patients undergoing ovarian stimulation with intracytoplasmic sperm injection. We demonstrated that the mean concentration of individual vitamins in FF correlated with their level in serum (p < 0.0001). The levels of vitamin D in FF were higher than in serum, while the opposite was observed for other analyzed vitamins. We did not observe a correlation between FF vitamin D concentration with fertilization success. However, we observed its association with embryo development status on day 3. Moreover, we showed a statistically significant negative correlation between the mean day 5 embryo score and the concentration of vitamin D in serum (rS = -0.68 p = 0.01) and follicular fluid (rS = -0.71 p = 0.01). Our study showed that FF concentration of vitamin A and E was helpful in the prediction of fertilization success of each individual oocyte. Moreover, vitamin A and E concentrations in FF were associated with status of embryo development on the third day of culture. Vitamin A was also associated with the embryo quality on day 2 and the embryo development status on day 5 after fertilization. In conclusion, a combination of FF vitamin analysis and routine morphological assessment could allow for a more accurate and sensitive method of determining embryonic developmental competence and enable the selection of a better embryo to transfer and perhaps translating into an increased chance of pregnancy.Abbreviations: in vitro fertilization: IVF; anti-Mullerian hormone: AMH; follicular fluid: FF; intracytoplasmic sperm injection: ICSI; top quality: TQ; vitamin D binding globulin level: VDBP; assisted reproductive technology: ART.

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.

Redox status assessment in infertile patients with non-obstructive azoospermia undergoing testicular sperm extraction: A prospective study

BACKGROUND

Oxidative stress (OS) is one of the most prevalent causes of sperm damage, through the toxic effects of endogenously generated hydrogen peroxide, superoxide anion, and hydroxyl radicals. Peripheral leukocytes represent a feasible model for studying the pathophysiology of OS-mediated homeostasis, which can be responsible for cell dysfunction and cell injury.

OBJECTIVE

To evaluate the redox status in patients with non-obstructive azoospermia (NOA), establishing the potential role exerted by reactive oxygen species (ROS) in the genesis of testicular secretory injury.

MATERIAL AND METHODS

From May 2018 to March 2019, 39 patients were enrolled in this prospective single-center cohort study and divided into two groups. Group 1 included 19 patients with NOA, and Group 2 included 20 normozoospermic men, partners of women with infertility tubal factor. All patients underwent serum blood tests. NOA underwent testicular sperm extraction (TeSE). ROS production (in lymphocytes, monocytes, and granulocytes) was assessed by fluorescence-activated cell sorting (FACS) analysis. Plasma oxidative stress was evaluated by lipid peroxidation markers (MDA) and total antioxidant capacity (TAC) both assessed by fluorometric techniques.

RESULTS

Mean lymphocyte ROS production resulted 967.0 ± 224.5 vs 728.0 ± 98.0 (NOA vs Controls, P < .001), monocyte ROS resulted 2102.5 ± 517.5 vs 1253 ± 171 (P < .001), and granulocyte ROS were 2366.5 ± 595.4 vs 1751.0 ± 213.0 (P < .001). Significant increases plasma lipid peroxidation markers were found in NOA patients compared with controls (2.7 ± 0.8 vs 0.37 ± 0.2 nmol/mL, P < .001). Significant decreased TAC was evident in NOA compared with controls (13.4 ± 3.9 vs 3.0 ± 0.2 µmol/mL Trolox equivalents, P < .001). No significant differences were found in blood leukocyte subpopulations ROS production, plasma lipid peroxidation, and TAC comparing groups (positive vs negative sperm retrieval, P > .05).

CONCLUSION

ROS production can be directly related to disorders of spermatogenesis, leading to severe conditions of male infertility, including azoospermia.

Proteomic profile of follicular fluid from patients with polycystic ovary syndrome (PCOS) submitted to in vitro fertilization (IVF) compared to oocyte donors

OBJECTIVE

The follicular fluid (FF) of women with polycystic ovary syndrome (PCOS) seems to exhibit a profile different from that of fertile women, which may be related to folliculogenesis disruption in PCOS patients. The aim of this study was to evaluate the differentially expressed proteins in the FF of women with PCOS compared to oocyte donors (ODs).

METHODS

This screening study included thirteen (13) women who underwent in vitro fertilization (IVF) cycles: seven (7) ODs and six (6) PCOS patients. The patients underwent standard ovarian stimulation, and the FF was analysed using ion trap and time-of-flight liquid chromatography-mass spectrometry (LCMS-IT-TOF).

RESULTS

The FF of the patients was matched to 229 proteins, with 61 proteins exclusive to the PCOS group, 123 proteins exclusive to the ODs, and 45 proteins found in both groups. We highlight fetuin-A and vitamin D ligand protein, which were exclusively expressed in the PCOS group; Complement C3 overexpressed in the PCOS group; and 26S protease only expressed in the OD group. The canonical pathways LXR/RXR activation, FXR/RXR activation, prothrombin activation are directly related to the disrupted metabolism and increased inflammatory status found in PCOS patients.

CONCLUSIONS

The findings of the differentially expressed proteins and matched pathways are associated with folliculogenesis, indicating it relevance to oocyte quality.

The effects of glycine-glutamine dipeptide replaced l-glutamine on bovine parthenogenetic and IVF embryo development

Relative to alanine and serine amino acid levels, glutamine is highly abundant in follicular fluid, and is an important source of energy required for oocyte maturation and embryo development. Thus, glutamine is an essential component of in vitro embryo culture media. However, glutamine has poor stability and degrades spontaneously in solution to form ammonia and pyrrolidonecarboxylic acid. In the present study, we aimed to explore the effect of substituting l-glutamine with glycine-glutamine, a more stable glutamine, on development of early parthenogenetic embryos and in vitro fertilization (IVF) embryos in bovine. Results revealed that glycine-glutamine can significantly increase cleavage rate (parthenogenetic embryos:87.24% vs. 72.61%, IVF embryos:89.33% vs. 83.79%, P < 0.01), blastocyst number (parthenogenetic embryos:24.98% vs. 18.07%, IVF embryos:33.53% vs. 27.29%, P < 0.01), and blastocyst number (parthenogenetic embryos:96 vs. 76, IVF embryos:114 vs. 109, P < 0.01), reduce blastocyst apoptosis (parthenogenetic embryos:3.72% vs. 6.65%, IVF embryos:2.53% vs.6.23%, P < 0.01), alleviate embryo ammonia toxicity, and reduce the content of reactive oxygen species (ROS) compared with the l-glutamine. In addition, glycine-glutamine can alter epigenetic reprogramming by increasing the expression of HDAC1 (Histone Deacetylase 1) and decreasing the relative expression levels of H3K9 acetylation in early parthenogenetic embryos and IVF embryos. From our present study, we concluded that glycine-glutamine is an effective substitute of glutamine in modified synthetic oviduct fluid with amino acids (mSOFaa).

Oxidative stress modulates the expression of apoptosis-associated microRNAs in bovine granulosa cells in vitro

Despite its essential role in ovulation, oxidative stress (OS) has been found to be cytotoxic to cells, while microRNAs (miRNAs) are known as a major regulator of genes involved in cellular defense against cytotoxicity. However, a functional link between OS and miRNA expression changes in granulosa cells (GCs) remains to be investigated. Here, we investigate the OS modulation of apoptosis-associated miRNAs and their biological relevance in bovine GCs. Following the evaluation of cell viability, accumulation of reactive oxygen species (ROS), cytotoxicity and mitochondrial activity, we used a ready-to-use miRNA PCR array to identify differentially regulated miRNAs. The results showed that exposure to 150 μM H₂O₂ for 4 h creates remarkable signs of OS in GCs characterized by more than 50% loss of cell viability, higher nuclear factor erythroid 2-related factor 2 (NRF2) nuclear translocation, significantly (p < 0.05) higher abundance of antioxidant genes, significantly (p < 0.001) higher accumulation of ROS, lower mitochondrial activity and a higher (p < 0.001) number of apoptotic nuclei compared to that of the control group. miRNA expression analysis revealed that a total of 69 miRNAs were differentially regulated in which 47 and 22 miRNAs were up- and downregulated, respectively, in stressed GCs. By applying the 2-fold and p < 0.05 criteria, we found 16 miRNAs were upregulated and 10 miRNAs were downregulated. Target prediction revealed that up- and downregulated miRNAs potentially targeted a total of 6210 and 3575 genes, respectively. Pathway analysis showed that upregulated miRNAs are targeting the genes involved mostly in cell survival, intracellular communication and homeostasis, cellular migration and growth control and disease pathways. Our results showed that OS modulates the expression of apoptosis-associated miRNAs that might have effects on cellular or molecular damages.

Impact of Oxidative Stress on Age-Associated Decline in Oocyte Developmental Competence

Reproductive capacity in women starts to decline beyond their mid-30s and pregnancies in older women result in higher rates of miscarriage with aneuploidy. Age-related decline in fertility is strongly attributed to ovarian aging, diminished ovarian reserves, and decreased developmental competence of oocytes. In this review, we discuss the underlying mechanisms of age-related decline in oocyte quality, focusing on oxidative stress (OS) in oocytes. The primary cause is the accumulation of spontaneous damage to the mitochondria arising from increased reactive oxygen species (ROS) in oocytes, generated by the mitochondria themselves during daily biological metabolism. Mitochondrial dysfunction reduces ATP synthesis and influences the meiotic spindle assembly responsible for chromosomal segregation. Moreover, reproductively aged oocytes produce a decline in the fidelity of the protective mechanisms against ROS, namely the ROS-scavenging metabolism, repair of ROS-damaged DNA, and the proteasome and autophagy system for ROS-damaged proteins. Accordingly, increased ROS and increased vulnerability of oocytes to ROS lead to spindle instability, chromosomal abnormalities, telomere shortening, and reduced developmental competence of aged oocytes.

Effects of sodium fluoride on the reproductive development of Bombyx mori

Bombyx mori was used as a model to evaluate the reproductive toxicity of NaF in insects. Significant reduction in cocoon quality, survival rate, fecundity, and hatchability were observed upon NaF treatment groups. Fluoride determination indicated that F^- has a cumulative effect on the gonad of silkworm. High-performance liquid chromatography revealed that the testosterone content of males was decreased in NaF-treated groups, and enzyme-linked immunosorbent assay showed that the estradiol content was decreased in NaF-treated females. Ultrastructural observation of testicles of silkworm larvae revealed mitochondrial turgescence, endoplasmic reticulum destruction, the appearance of vacuoles and lysosomes, and apoptosis and necrosis of cells in NaF-treated groups. Altered tail length and tail DNA content in Comet assays further confirmed DNA damage in NaF-treated larvae. We demonstrated reproductive toxicity of fluoride toward silkworm at physiological and biochemical levels, and the results provide a theoretical basis for revealing the reproductive toxicity of fluoride in terrestrial insects.

CoQ10 Supplementation in Patients Undergoing IVF-ET: The Relationship with Follicular Fluid Content and Oocyte Maturity

Background: The target of the reduced fecundity with aging is the oocyte. The follicular fluid and its components are strongly linked with the environment of the maturing oocyte. The aim of the present study was to evaluate CoQ10 bioavailability in follicular fluids after oral supplementation and its possible implication in oocyte maturation. Methods: Fifteen female partners of infertile couples, aged 31–46, undergoing IVF-ET and taking 200 mg/day oral CoQ10 were compared to unsupplemented patients. CoQ10 content, its oxidative status and total antioxidant capacity were evaluated also in relation to oocyte maturation indexes. Results: CoQ10 supplementation produced a significant increase in follicular content and a significant improvement of its oxidative status. Follicular fluid total antioxidant capacity highlighted a significant decrease in patients supplemented with CoQ10, specially in women >35 years. CoQ10 supplementation was associated with a significant decrease in total antioxidant capacity of fluid from follicles containing mature oocyte, moreover CoQ10 oxidative status was also significantly reduced but in follicles containing immature oocyte. Conclusions: Our observation leads to the hypothesis that the oral supplementation of CoQ10 may improve follicular fluid oxidative metabolism and oocyte quality, specially in over 35-year-old women.

Comparison of antagonist mild and long agonist protocols in terms of follicular fluid total antioxidant capacity

OBJECTIVE

A high dose of prolonged gonadotropins can yield higher numbers of oocytes and embryos. The high dose or prolonged regimens can be associated with ovarian hyperstimulation syndrome (OHSS), multiple gestations, emotional stress, economical burden and treatment dropout. In mild stimulation lower doses and shorter duration times of gonadotropin are used in contrast to the conventional long stimulation protocol in IVF. It has been proposed that supraphysiologic levels of hormones may adversely affect endometrium and oocyte/embryo. Also it has been proposed that oxidative stress (OS) may alter ovarian hormone dynamics and could be further affected by additional exogenous hormonal stimulation. Therefore our aim was to compare follicular fluid total antioxidant capacity (TAC) in antagonist mild and long agonist stimulations.

MATERIALS AND METHODS

Forty patients received antagonist mild stimulation, starting on the 5th day of their cycle and forty patients received long agonist treatment. Seventy-five patients undergoing their first IVF cycle were included in the final analysis. Follicular fluid (FF) samples were analyzed for estradiol (E2), antimullerian hormone (AMH) and TAC.

RESULTS

FF-Total antioxidant capacity (TAC) levels were higher in the long agonist group as opposed to the antagonist group [1.07 ± 0.04 mmol Trolox equivalent/L vs 1 ± 0.13 mmol Trolox equivalent/L] (Fig. 1). Pregnancy rates were not significantly different between the two treatments. The FF-TAC levels were not different among infertility etiologies (Fig. 3). FF-TAC levels did not have a direct correlation with pregnancy but a positive correlation with the total gonadotropin dose was observed.

CONCLUSION

Patients with good ovarian reserves and under the age of 35 effectively responded to mild stimulation treatment. Using lower amounts of gonadotropin, yielded less FF-TAC levels in patients who underwent antagonist mild protocol. In patients under the age of 35, antagonist mild stimulation is a patient friendly and effective procedure when undergoing their first IVF cycle.

DNA fragmentation in two cytometric sperm populations: relationship with clinical and ultrasound characteristics of the male genital tract

We investigated whether DNA fragmentation in two cytometric sperm populations (PIdimmer and PIbrighter) with different biological characteristics and clinical relevance is related to clinical and color-Doppler ultrasound (CDUS) parameters of the male genital tract. One hundred and sixty males of infertile couples without genetic abnormalities were evaluated for clinical, scrotal, and transrectal CDUS characteristics, presence of prostatitis-like symptoms (with the National Institutes of Health-Chronic Prostatitis Symptom Index) and sperm DNA fragmentation (sDF) in PIdimmer and PIbrighter populations (using TUNEL/PI method coupled with flow cytometry). Data were adjusted for age (Model 1) along with waistline, testosterone levels, smoking habit, and sexual abstinence (Model 2). According to the statistical Model 2, PIdimmer sDF was associated with testicular abnormalities, including lower clinical and ultrasound volume (r = -0.21 and r = -0.20, respectively; P < 0.05), higher FSH levels (r = 0.34, P < 0.0001) and occurrence of testicular inhomogeneity (P < 0.05) and hypoechogenicity (P < 0.05). PIbrighter sDF was associated with prostate-related symptoms and abnormal signs, including higher NIH-CPSI total and subdomain scores, a higher prevalence of prostatitis-like symptoms and of CDUS alterations such as macro-calcifications, severe echo-texture inhomogeneity, hyperemia (all P < 0.05), and higher arterial peak systolic velocity (r = 0.25, P < 0.05). Our results suggest that DNA fragmentation in PIdimmer sperm, which is related to poor semen quality, mainly originates in the testicles, likely due to apoptosis. Conversely, DNA fragmentation in PIbrighter sperm appears to mainly originate during or after transit through the prostate, increasing with the presence of an inflammatory status of the organ. These results could lead to new perspectives for the identification of therapeutic targets to reduce sDF.

A Biochemical Approach to Detect Oxidative Stress in Infertile Women Undergoing Assisted Reproductive Technology Procedures

Oxidative stress plays a major role in critical biological processes in human reproduction. However, a reliable and biologically accurate indicator of this condition does not yet exist. On these bases, the aim of this study was to assess and compare the blood and follicular fluid (FF) redox status of 45 infertile subjects (and 45 age-matched controls) undergoing in vitro fertilization (IVF), and explore possible relationships between the assessed redox parameters and IVF outcomes. Reactive Oxygen Species (ROS) production, assessed by flow cytometry analysis in blood leukocytes and granulosa cells, significantly increased (p < 0.05) in infertile patients. Also, oxidative stress markers—ThioBarbituric Acid-Reactive Substances (TBARS) as an index of lipid peroxidation, and Oxygen Radical Absorbance Capacity (ORAC) to account for total antioxidant capacity, both assayed by fluorometric procedures—in blood and FF were significantly (p < 0.001) modified in infertile patients compared to the control group. Moreover, a significant correlation between blood redox markers and FF redox markers was evident. An ORAC/TBARS ratio, defined as the redox index (RI), was obtained in the plasma and FF of the patients and controls. In the patients, the plasma RI was about 3.4-fold (p < 0.0001) lower than the control, and the FF RI was about six-fold (p < 0.0001) lower than the control. Interestingly, both the plasma RI and FF RI results were significantly correlated (p < 0.05) to the considered outcome parameters (metaphase II, fertilization rate, and ongoing pregnancies). Given the reported findings, a strict monitoring of redox parameters in assisted reproductive techniques and infertility management is recommended.

Silica nanoparticle exposure inducing granulosa cell apoptosis and follicular atresia in female Balb/c mice

Given that the effects of ultrafine fractions (< 0.1 μm) on reproductive diseases are gaining attention, this study aimed to explore the influence of silica nanoparticle (SiNP)-induced female reproductive dysfunction. In this study, 80 female mice were randomly divided into four groups including a control group and three concentrations of SiNP groups (7, 21, 35 mg/kg). Mice were exposed to the vehicle control and silica nanoparticles by tracheal perfusion every 3 days a total of five times in 15 days. Then, half of the mice in each group were sacrificed on 15 and 30 days after the first dose, respectively. Our findings indicated that SiNPs can result in ovarian damage, cause an imbalance of sex hormones, increase the number of atretic and primary follicles, and induce oxidative stress and DNA strand breaks in ovary by day 15. The protein expressions of ATM, CHK-2, P53, E2F1, P73, BAX, Caspase-9, and Caspase-3 were significantly increased, while expressions of RAD51 were down-regulated after SiNP exposure by days 15. Estradiol increased, while progesterone increased in low dose and decreased in high dose after SiNP exposure by 15 days. However, these changes were recovered by 30 days. The results suggest that SiNPs can cause reversible damage to follicles in mice. SiNPs could primarily cause DNA damage and DNA damage response through oxidative stress, while DNA damage repair failure because of severe DNA damage activated the mitochondrial apoptosis pathway and therefore resulted in apoptosis of granulosa cell. In addition, the disorder of reproductive endocrine function caused by SiNPs could be another reason for SiNP-induced reproductive dysfunction in mice. These events in turn induce the follicles to undergo atresia.

MDA and GSH-Px Activity in Transition Dairy Cows Under Seasonal Variations and their Relationship with Reproductive Performance

Introduction

The purpose of the current study was to evaluate the blood glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) levels under seasonal variations in dairy cows during transition period, and to assess the relationship between chosen reproductive parameters, GSH-Px, and MDA.

Material and Methods

Holstein cows calving in January were assigned into winter group (n = 42), while cows calving in August were assigned into summer group (n = 42). Blood samples were collected from the jugular vein 21, 14, and 7 days before calving, at calving (0 day), and 7, 14, and 21 days after calving. Reproductive parameters obtained from farm records were evaluated.

Results

In both groups of cows, GSH-Px activity decreased from 21 days before calving to day 0, and it gradually continued to increase until 21 days after calving. GSH-Px activity was higher in winter group compared to summer group during the transition period (P < 0.05). MDA levels in both groups increased over time starting from 21 days before calving to 0 day, but it gradually decreased thereafter. MDA levels were higher in summer group compared to winter group during the transition periods (P < 0.05). Summer group of cows showed higher intervals of calving-to-oestrus, calving-to-conception, and higher insemination index (P < 0.01). Negative correlation was recorded between GSH-Px and MDA during all examination days (P < 0.01). MDA levels correlated with calving to conception interval on day 21 before calving and day 0 (P < 0.01) and insemination index on day 0 and 21 days after calving (P < 0.01). GSH-Px activity was negatively correlated with calving to conception interval on day 21 before calving, day 0, and 21 days (P < 0.01) after calving. Negative correlation on day 21 before calving and day 0 was also determined between GSH-Px and insemination index (P < 0.01).

Conclusion

This study showed that blood oxidant and antioxidant levels have affected the fertility parameters in cows under seasonal variations.

Proteomic analysis of human follicular fluid in poor ovarian responders during in vitro fertilization

Poor ovarian response (POR) in controlled ovarian stimulation is often observed during in vitro fertilization and embryo transfer cycles and it is a major problem. A POR has been found to be related to several factors, including advanced age, high body mass index, and history of ovarian or pelvic surgery. However, it is difficult to predict POR, as there are no specific biomarkers known. In this study, we used quantitative proteomic analyses to investigate potential biomarkers that can predict poor response during in vitro fertilization based on follicular fluid samples. A total of 1079 proteins were identified using a high-resolution orbitrap mass spectrometer coupled online to a nanoflow-LC system. It is notable that 65 upregulated and 66 downregulated proteins were found to be functionally enriched in poor responders. We also validated these differentially expressed proteins using a triple-quadrupole mass spectrometer for quantification of targeted proteins. Of the differentially expressed proteins, three proteins (pregnancy zone protein, renin, and sushi repeat-containing protein SRPX) were regarded as statistically significant (p < 0.05).

Follicular fluid biomarkers for human in vitro fertilization outcome: Proof of principle

Background

Human follicular fluid (FF) is a unique biological fluid in which the oocyte develops in vivo, and presents an optimal source for non-invasive biochemical predictors. Oocyte quality directly influences the embryo development and hence, may be used as a predictor of embryo quality. Peptide profiling of FF and its potential use as a biomarker for oocyte quality has never been reported.

Methods

This study screened FF for peptide biomarkers that predict the outcome of in vitro fertilization (IVF). Potential biomarkers were discovered by investigating 2 training datasets, consisting both of 17 samples and validating on an independent experiment containing 32 samples. Peptide profiles were acquired by nano-scale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS).

Results

From the training datasets 53 peptides were found as potential biomarker candidates, predicting the fertilization outcome of 24 out of the 32 validation samples blindly (81.3% sensitivity, 68.8% specificity, AUC = 0.86). Seven potential biomarker peptides were identified. They were derived from: insulin-like growth factor binding protein-5, alpha-2-antiplasmin, complement component 3, inter-alpha-trypsin inhibitor heavy chain H1, serum albumin, protein diaphanous homolog 1 and plastin-3.

Conclusions

The MS-based comprehensive peptidomic approach carried out in this study, established a novel panel of potential biomarkers that present a promising predictive accuracy rate in fertilization outcome, and indicates FF as an interesting biomarker resource to improve IVF clinic routine.

Electronic supplementary material

The online version of this article (doi:10.1186/s12953-016-0106-9) contains supplementary material, which is available to authorized users.

Myeloperoxidase as a Potential Target in Women With Endometriosis Undergoing IVF

As infertility is intimately associated with endometriosis, the levels of myeloperoxidase (MPO), a leukocyte enzyme and an oxidative stress marker, were determined in a case-control prospective study of 68 women with and without endometriosis undergoing in vitro fertilization in the outpatient fertility center within a tertiary care academic medical center. Measured values included plasma and follicular fluid (FF) concentrations of MPO, plasma estradiol, as well as oocyte quality, fertilization, implantation, and pregnancy rates in these women. In FF (mean ± standard error of mean [SEM]), the MPO concentrations (ng/mL) for controls were 4.3 ± 0.37, mild endometriosis (stages I-II) 3.9 ± 0.17, and moderate/severe endometriosis (stages III-IV) 16.6 ± 12.5 ( P < 0.0143). In FF, among patients supplemented with vitamins E and C, the MPO levels decreased significantly only in moderate/severe endometriosis from 25.3 ± 22.0 ng/mL to 4.9 ± 1.61 ng/mL, respectively. Plasma levels of MPO between groups did not change. Outcome data revealed a trend toward decreased percentage of mature oocytes, implantation rate, and clinical pregnancy rate with severity of endometriosis and MPO levels. Myeloperoxidase may be a potential oxidative stress target for endometriosis-associated infertility.

Antioxidants reduce oxidative stress in follicular fluid of aged women undergoing IVF

BACKGROUND

The status characterized by the imbalance between pro-oxidants and antioxidants molecules, defined as oxidative stress, has been suggested to be involved in the pathogenesis of subfertility in females. This study aims to evaluate the impact of a complete micronutrients supplementation on oxidative stress levels in follicular microenvironment as well as on in vitro fertilization (IVF) outcome.

METHODS

This preliminary study was conducted between January 2014 and July 2015 at the Siena University Hospital Infertility Clinic. Serum and follicular fluid were collected from infertile women aged > 39 years who underwent two in vitro fertilization cycles: in the first cycle they were treated with GnRH-antagonist protocol and gonadotropins for controlled ovarian hyperstimulation, whereas in the second cycle ovarian stimulation protocol was associated to micronutrients supplementation, starting three months earlier. Protein oxidation levels and total antioxidant capacity in serum and in follicular fluid were evaluated in IVF cycles with or without micronutrients supplementation. Differences in IVF outcome parameters were statistically evaluated.

RESULTS

Two-dimensional electrophoresis analyses demonstrated that when patients assumed micronutrients before IVF cycles, follicular fluid and serum proteins were protected from oxidative damage. Comparable results were obtained when total antioxidant capacity was measured. Moreover, the mean number of good quality oocytes retrieved when patients received micronutrients supplementation was significantly increased.

CONCLUSION

The additional treatment with micronutrients, starting three months before IVF cycles, protects the follicular microenvironment from oxidative stress, thus increasing the number of good quality oocytes recovered at the pick up.

Protein pathways working in human follicular fluid: the future for tailored IVF?

The human follicular fluid (HFF) contains molecules and proteins that may affect follicle growth, oocyte maturation and competence acquiring. Despite the numerous studies, an integrated broad overview on biomolecular and patho/physiological processes that are proved or supposed to take place in HFF during folliculogenesis and oocyte development is still missing. In this review we report, for the first time, all the proteins unambiguously detected in HFF and, applying DAVID (Database for Annotation, Visualization and Integrated Discovery) and MetaCore bioinformatic resources, we shed new lights on their functional correlation, delineating protein patterns and pathways with reasonable potentialities for oocyte quality estimation in in vitro fertilisation (IVF) programs. Performing a rigorous PubMed search, we redacted a list of 617 unique proteins unambiguously-annotated as HFF components. Their functional processing suggested the occurrence in HFF of a tight and highly dynamic functional-network, which is balanced by specific effectors, primarily involved in extracellular matrix degradation and remodelling, inflammation and coagulation. Metalloproteinases, thrombin and vitamin-D-receptor/retinoid-X-receptor-alpha resulted as the main key factors in the nets and their differential activity may be indicative of ovarian health and oocyte quality. Despite future accurate clinical investigations are absolutely needed, the present analysis may provide a starting point for more accurate oocyte quality estimation and for defining personalised therapies in reproductive medicine.

Follicular fluid total antioxidant capacity levels in PCOS

In this study, our aim was to assess total antioxidant capacity (TAC) levels in follicular fluid (FF) and their relationship to clinical pregnancy rates in PCOS patients undergoing assisted reproduction (ART). Twenty-two women with polycystic ovary syndrome (PCOS) (Group 1) and 41 women without PCOS (Group 2) were included in this study. Clinical and laboratory parameters and FF TAC levels were investigated. No statistically significant differences were found between the groups with regard to age and baseline parameters. Although we could not demonstrate a significant difference in FF TAC levels between the two groups (p=0.469), there was a significant positive correlation between FF TAC and clinical pregnancy rates, BMI, and the duration of infertility for the entire group (r=0.254, p=0.048; r=0.312, p=0.013; r=0.259, p=0.040; respectively). Owing to the correlation between FF TAC and the clinical pregnancy rates, further studies evaluating the impact of FF TAC levels on ART outcomes in patients with PCOS and other etiologies of infertility are needed.

Acute iron overload leads to hypothalamic-pituitary-gonadal axis abnormalities in female rats

Iron plays a critical role in a mammal's physiological processes. However, iron tissue deposits have been shown to act as endocrine disrupters. Studies that evaluate the effect of acute iron overload on hypothalamic-pituitary-gonadal (HPG) axis health are particularly sparse. This study demonstrates that acute iron overload leads to HPG axis abnormalities, including iron accumulation and impairment in reproductive tract morphology. Female rats were treated with iron-dextran (Fe rats) to assess their HPG morphophysiology. The increasing serum iron levels due to iron-dextran treatment were positively correlated with higher iron accumulation in the HPG axis and uterus of Fe rats than in control rats. An increase in the production of superoxide anions was observed in the pituitary, uterus and ovary of Fe rats. Morphophysiological reproductive tract abnormalities, such as abnormal ovarian follicular development and the reduction of serum estrogen levels, were observed in Fe rats. In addition, a significant negative correlation was obtained between ovary superoxide anion and serum estrogen levels. Together, these data provide in vivo evidence that acute iron overload is toxic for the HPG axis, a finding that may be associated with the subsequent development of the risk of reproductive dysfunction.