Effect of follicular fluid oxidative stress parameters on intracytoplasmic sperm injection outcome

Oxidative Homeostasis in Follicular Fluid and Embryo Quality-A Pilot Study

The objective of this study was to measure the different redox biomarker levels within the follicular fluid (FF) and evaluate correlations with embryo quality using the one follicle-one oocyte/embryo approach. The prospective study included 54 women (average age 34.6 ± 3.0 years). Out of the 235 mature metaphase II cells that underwent intracytoplasmic sperm injection, fertilization was achieved in 177 cells, producing 92 Grade I embryos, 26 Grade II embryos, 39 Grade III embryos, and 20 Grade IV embryos. The activities of antioxidant enzymes, superoxide dismutase, glutathione peroxidase, and glutathione transferase were significantly higher in the group consisting of lower-quality (Grades II-IV) embryos in comparison with top-quality (Grade I) embryos (p = 0.011; p = 0.021; p = 0.008, respectively). The concentration of oxidative stress markers, malondialdehyde, 8-hydroxy-2'-deoxyguanosine, and thiol groups was significantly increased in the group with lower-quality embryos (Grades II-IV) compared to top-quality embryos (0.027; 0.018; 0.021, respectively). Furthermore, a significant positive correlation between each oxidative marker and the activities of antioxidant enzymes was observed (p < 0.001). According to our findings, the best embryos and, consequently, better in vitro fertilization outcomes are linked to low levels of oxidative stress and low antioxidant enzyme activity.

Advanced Glycation End-Products of Follicular Fluid are Associated with Embryo Morphokinetic Parameters and ART Outcomes

Advanced glycation end products (AGEs) can disrupt antioxidant system and steroidogenesis, resulting in detrimental effects on assisted reproductive technology (ART) outcomes. This study aimed to investigate the association of AGEs in follicular fluid (FF) with morphokinetic parameters of embryos and ART outcomes. Fifty women undergoing ART treatment were studied. AGEs, glucose, 25(OH) vitamin D, malondialdehyde (MDA) levels and catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPX) activities were evaluated in FF. The expression of 3βHSD, CYP11A1, and CYP19A1 genes were analyzed in granulosa cells (GCs) by qRT-PCR technique. Morphokinetic parameters were evaluated using time-lapse technology. The FF level of AGEs was reversely associated with CAT, SOD, and GPX activities, and total and mature oocytes number, blastocyst formation rate, and high-grade embryos number, while it showed positive correlations with the FF MDA levels, the expression of steroidogenesis genes, number of immature oocytes, morphokinetic parameters, and number of low-grade embryos. Furthermore, the level of vitamin D in FF had an inverse association with AGEs and positive correlations with ART outcomes and morphokinetic parameters. Comparison between the those with positive and negative biochemical pregnancy showed no significant differences in terms of FF factors and just the expression of 3βHSD, CYP11A1, and CYP19A1 genes were higher in pregnant women (p < 0.05). AGEs could delay blastomere division and lead to an increase in the number of low-quality embryos, while vitamin D have an adverse effect on AGEs and a protective function against AGEs negative effects.

Oxidative stress in donor mares for ovum pick-up delays embryonic development

The in vitro production of equine embryos via ovum pick-up (OPU) and intracytoplasmic sperm injection (ICSI) has increased rapidly. There is a marked effect of the individual mare on the outcome of OPU-ICSI, but little is known about the influence of the mare's health condition. This study aimed to investigate the potential associations between the concentrations of interleukin-6 (IL-6), reactive oxygen metabolites (d-ROMs), and biological antioxidant potential (BAP) in serum of oocytes' donor mares and the subsequent embryonic development. Just before OPU, a blood sample was collected from 28 Warmblood donor mares, that were subjected to a routine OPU-ICSI program. The serum concentrations of IL-6, d-ROMs, and BAP were assayed photometrically. The maturation, cleavage and blastocyst rate as well as the kinetics of blastocyst development were recorded. The average blastocyst rate was 24.68 ± 5.16% and the average concentrations of IL-6, d-ROMs, and BAP were 519.59 ± 157.08 pg/mL, 171.30 ± 4.55 carratelli units (UCARR), and 2711.30 ± 4.55 μmol/L, respectively. Serum concentrations of IL-6, d-ROMs, and BAP were not significantly different between mares yielding at least one blastocyst (552.68 ± 235.18 pg/mL, 168.36 ± 5.56 UCARR, and 2524.80 ± 159.55 μmol/L) and mares yielding no blastocysts (468.47 ± 179.99 pg/mL, 175.85 ± 7.89 UCARR, and 2999.50 ± 300.13 μmol/L, respectively). Serum concentrations of d-ROMs were significantly lower in mares with fast growing (at day 7-8 post ICSI; 148.10 ± 8.13 UCARR) compared to those with slow growing blastocysts (≥ day 9 post ICSI; 179.41 ± 4.89 UCARR; P = 0.003). Taken together, the serum concentration of IL-6, d-ROMs, and BAP do not determine the mare's ability to produce blastocysts in vitro. Although it may be questioned whether a single sample is representative of the mare's health status, changes in serum metabolites related to oxidative stress at the time of oocyte retrieval were linked to a delayed blastocyst development in a clinical OPU-ICSI outcome.

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.

Chronic low-grade inflammation and ovarian dysfunction in women with polycystic ovarian syndrome, endometriosis, and aging

The ovarian microenvironment is critical for follicular development and oocyte maturation. Maternal conditions, including polycystic ovary syndrome (PCOS), endometriosis, and aging, may compromise the ovarian microenvironment, follicular development, and oocyte quality. Chronic low-grade inflammation can induce oxidative stress and tissue fibrosis in the ovary. In PCOS, endometriosis, and aging, pro-inflammatory cytokine levels are often elevated in follicular fluids. In women with obesity and PCOS, hyperandrogenemia and insulin resistance induce ovarian chronic low-grade inflammation, thereby disrupting follicular development by increasing oxidative stress. In endometriosis, ovarian endometrioma-derived iron overload can induce chronic inflammation and oxidative stress, leading to ovarian ferroptosis and fibrosis. In inflammatory aging (inflammaging), senescent cells may secrete senescence-associated secretory phenotype factors, causing chronic inflammation and oxidative stress in the ovary. Therefore, controlling chronic low-grade inflammation and fibrosis in the ovary would present a novel therapeutic strategy for improving the follicular microenvironment and minimizing ovarian dysfunction.

Repeated controlled ovarian stimulation-induced ovarian and uterine damage in mice through the PI3K/AKT signaling pathway

The effects of repeated controlled ovarian stimulation (COS) on the female reproductive system are still controversial. This study investigated the effects of repeated COS on the ovaries and uterus of mice and its possible mechanism. Female ICR (Institute of Cancer Research) mice were subjected to the COS using pregnant mare serum gonadotropin (PMSG) and human chorionic gonadotropin (hCG) for 1, 3, 5, and 7 cycles. Serum hormone levels, reactive oxidative stress (ROS), 8-hydroxy-2'-deoxyguanosine (8-OHdG), total antioxidant capacity (T-AOC), and superoxide dismutase (SOD) in the mouse ovary and uterus were analyzed by ELISA. The morphology of the ovary and endometrium, ovarian apoptosis, and expressions of the vascular endothelial growth factor (VEGF), leukemia inhibitory factor (LIF), PI3K, AKT, Bax, and Bcl-2 in the ovarian and uterine tissues were tested by hematoxylin-eosin (HE) staining, immunohistochemistry, and western blot. The results showed that repeated COS significantly decreased the hormone level (estradiol, progesterone and anti-Müllerian hormone), high-quality of the MII oocyte ratio, oocyte and embryo number, antioxidant capacity (T-AOC, SOD activity), and the protein level of Bcl-2, LIF, and VEGF, but increased the oxidative damage (ROS, 8-OHdG content), embryo fragment ratio, and expression of pro-apoptotic protein Bax. In addition, the expressions of p-PI3K and p-AKT also decreased with the increase of COS cycle. In conclusion, repeated COS causes ovarian and uterus damage possibly through the PI3K/AKT signaling pathway, and this finding may provide some experimental basis for guiding clinical treatment.

Ovarian aging: mechanisms and intervention strategies

Ovarian reserve is essential for fertility and influences healthy aging in women. Advanced maternal age correlates with the progressive loss of both the quantity and quality of oocytes. The molecular mechanisms and various contributing factors underlying ovarian aging have been uncovered. In this review, we highlight some of critical factors that impact oocyte quantity and quality during aging. Germ cell and follicle reserve at birth determines reproductive lifespan and timing the menopause in female mammals. Accelerated diminishing ovarian reserve leads to premature ovarian aging or insufficiency. Poor oocyte quality with increasing age could result from chromosomal cohesion deterioration and misaligned chromosomes, telomere shortening, DNA damage and associated genetic mutations, oxidative stress, mitochondrial dysfunction and epigenetic alteration. We also discuss the intervention strategies to delay ovarian aging. Both the efficacy of senotherapies by antioxidants against reproductive aging and mitochondrial therapy are discussed. Functional oocytes and ovarioids could be rejuvenated from pluripotent stem cells or somatic cells. We propose directions for future interventions. As couples increasingly begin delaying parenthood in life worldwide, understanding the molecular mechanisms during female reproductive aging and potential intervention strategies could benefit women in making earlier choices about their reproductive health.

OXIDATIVE STRESS AND REPRODUCTIVE FUNCTION: Oxidative stress in polycystic ovary syndrome

In brief

A genetic, epigenetic, and environmental association exists between oxidative stress (OS) and polycystic ovary syndrome (PCOS), expressed in a multifaceted clinical profile. This review summarizes and discusses the role of OS in the pathogenesis of PCOS syndrome, focusing on metabolic, reproductive, and cancer complications.

Abstract

Oxidative stress (OS), an imbalance between oxidants and antioxidants in cells, is one of many factors playing essential roles in the pathogenesis of polycystic ovary syndrome (PCOS). PCOS is described mainly as a disproportion of reproductive hormones, leading to chronic anovulation and infertility in women. Interestingly, OS in PCOS may be associated with many disorders and diseases. This review focuses on characteristic markers of OS in PCOS and the relationship between OS and PCOS related to insulin resistance (IR), hyperandrogenemia, obesity, chronic inflammation, cardiovascular diseases, and cancer. Interestingly, in patients with PCOS, an increase in oxidative status and insufficient compensation of the increase in antioxidant status before any cardiovascular complications are observed. Moreover, free radicals promote carcinogenesis in PCOS patients. However, despite these data, it has not been established whether oxygen stress influences PCOS development or a secondary disorder resulting from hyperglycemia, IR, and cardiovascular and cancer complications in women.

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.

Cumulus cell antioxidant system is modulated by patients' clinical characteristics and correlates with embryo development

PURPOSE

To study whether the cumulus cell antioxidant system varies accordingly to patients clinical characteristics' as age, infertility diagnosis, BMI, and stimulation protocol applied and if the antioxidant profile of cumulus cells could be used as a predictor of embryo development.

METHODS

A prospective study including 383 human cumulus samples provided by 191 female patients undergoing intracytoplasmic sperm injection during in vitro fertilization treatments from a local in vitro fertilization center and processed in university laboratories. Catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx), and glutathione S-transferase (GST) enzyme activity levels and reduced glutathione (GSH) levels were measured in cumulus oophorus cells individually collected from each aspirated cumulus-oocyte complex, and the results of each sample were compared considering the oocytes outcome after ICSI and patients clinical characteristics. A total of 223 other human cumulus samples from previous studies were submitted to a gene expression meta-analysis.

RESULTS

The antioxidant system changes dramatically depending on patients' age, infertility diagnosis, stimulation protocol applied, and oocyte quality. SOD activity in cumulus cells revealed to be predictive of top-quality blastocysts for young patients with male factor infertility (P < 0.05), while GST levels were shown to be extremely influenced by infertility cause (P < 0.0001) and stimulation protocol applied (P < 0.05), but nonetheless, it can be used as a complementary tool for top-quality blastocyst prediction in patients submitted to intracytoplasmic sperm injection technique (ICSI) by male factor infertility (P < 0.05).

CONCLUSION

Through a simple and non-invasive analysis, the evaluation of redox enzymes in cumulus cells could be used to predict embryo development, in a personalized matter in specific patient groups, indicating top-quality oocytes and improving success rates in in vitro fertilization treatments.

TRIAL REGISTRATION

The trial was registered at UFRGS Research Ethics Committee and Plataforma Brasil under approval number 68081017.2.0000.5347 in June 6, 2019.

Oxidative stress and DNA damage status in couples undergoing in vitro fertilization treatment

This study examined the status of oxidative stress in 599 couples undertaking in vitro fertilization (IVF) treatment and its association with reproductive hormones, smoking, and outcomes. Oxidative stress biomarkers such as malondialdehyde, 8-hydroxy-2-deoxyguanosine, hydrogen peroxide (H₂O₂), catalase (CAT), and total antioxidant capacity (TAC) were determined in follicular fluid and seminal plasma. Tail moment (TM) was used to evaluate DNA damage in the sperm and granulosa cells. Reproductive hormones in serum and cotinine (COT) in urine, follicular fluid, and seminal plasma samples were determined. Separate multivariate linear regression was used to assess associations between levels of each oxidative stress biomarker and each hormone and smoking parameter (modeled as natural log-transformed). The findings indicate that some oxidative stress and DNA damage biomarkers played a role in disrupting certain reproductive hormones in women and their male partners either by overproducing reactive oxygen species or reducing antioxidant defense capacity. Although women were nonsmokers, COT levels > 50 and 10 µg/L in urine and follicular were observed in 5.7 and 1.7%, respectively. Levels of follicular fluid COT were positively associated with H₂O₂ and TM. We used log-binomial multivariate regression to estimate relative risks for the association between oxidative stress/DNA damage and IVF binary outcomes (fertilization rate > 50%, biochemical pregnancy, clinical pregnancy, and live birth). An increase in the CAT levels of follicular fluid was associated with a 48 and 41% decrease in the risk of poor fertilization rate (≤50%) and unsuccessful live birth, respectively. After the models were adjusted for hormonal factors, the associations remained the same, except that the elevated TAC in follicular fluid became significantly associated with a decrease of 42% in the risk of poor fertilization rate (≤50%). The higher antioxidant activity (CAT and TAC) in follicular fluid might positively impact specific IVF outcomes.

Research progress of melatonin (MT) in improving ovarian function: a review of the current status

Melatonin (MT) is an endogenous hormone mainly synthesized by pineal cells, which has strong endogenous effects of eliminating free radicals and resisting oxidative damages. Melatonin (MT) can not only regulate the body’s seasonal and circadian rhythms; but also delay ovarian senescence, regulate ovarian biological rhythm, promote follicles formation, and improve oocyte quality and fertilization rate. This review aimd to provide evidence concerning the synthesis and distribution, ovarian function, and role of MT in development of follicles and oocytes. Moreover, the role of MT as antioxidative, participating in biological rhythm regulation, was also reviewed. Furthermore, the effects of MT on various ovarian related diseases were analyzed, particularly for the ovarian aging and polycystic ovary syndrome (PCOS).

Mitochondria in Ovarian Aging and Reproductive Longevity

Mitochondrial dysfunction is one of the hallmarks of aging. Consistently mitochondrial DNA (mtDNA) copy number and function decline with age in various tissues. There is increasing evidence to support that mitochondrial dysfunction drives ovarian aging. A decreased mtDNA copy number is also reported during ovarian aging. However, the mitochondrial mechanisms contributing to ovarian aging and infertility are not fully understood. Additionally, investigations into mitochondrial therapies to rejuvenate oocyte quality, select viable embryos and improve mitochondrial function may help enhance fertility or extend reproductive longevity in the future. These therapies include the use of mitochondrial replacement techniques, quantification of mtDNA copy number, and various pharmacologic and lifestyle measures. This review aims to describe the key evidence and current knowledge of the role of mitochondria in ovarian aging and identify the emerging potential options for therapy to extend reproductive longevity and improve fertility.

Growth hormone alleviates oxidative stress and improves oocyte quality in Chinese women with polycystic ovary syndrome: a randomized controlled trial

Oxidative stress (OS) is associated with poor oocyte quality and in vitro fertilization and embryo transfer (IVF-ET) outcomes for patients with polycystic ovary syndrome (PCOS). Growth hormone (GH) can function to reduce OS in some types of cells. Therefore, this prospective randomized study investigated whether GH can significantly improve OS and oocyte quality in women with PCOS. This study enrolled 109 and 50 patients with and without PCOS (controls), respectively. The patients with PCOS were randomly assigned to receive treatment with GH (PCOS-T) or not (PCOS-C). The primary outcome included markers of OS in serum and FF, and secondary outcomes were mitochondrial function in granulosa cells (GCs) and IVF-ET outcomes. The PCOS groups showed higher basal serum total oxidant status (TOS) and OS index (OSI) levels. The follicle fluid (FF) TOS and OSI and GC apoptosis rate were significantly higher, whereas the GC mitochondrial membrane potential (MMP) was significantly lower in the PCOS-C group than in the PCOS-T and non-PCOS control groups (P < 0.05). Significantly more oocytes were fertilised and cleavage stage embryos were produced in the PCOS-T group than in the PCOS-C group (P < 0.05). GH also improved the rates of implantation and clinical pregnancy, but not significantly (P > 0.05). This study showed that GH alleviated the TOS and OSI level in FF and improved GC mitochondrial dysfunction and oocyte quality in patients with PCOS.

Clinical Trial Registration Number: This project was prospectively registered on the Chinese Clinical Trial Registry on October 20, 2018. (ChiCTR1800019437) (https://www.chictr.org.cn/edit.aspx?pid=28663&htm=4).

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.

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.

Estradiol and Progesterone Levels are Related to Redox Status in the Follicular Fluid During in vitro Fertilization

Studies have reported a possible association between the levels of oxidative stress biomarkers in follicular fluid (FF) and infertility treatment outcomes. FF analysis can provide important information about oocyte quality. This study aimed to evaluate the possible correlation between oxidative stress biomarker and intrafollicular hormone levels and clinical and laboratory parameters in women during controlled ovarian stimulation. These women were undergoing in vitro fertilization with intracytoplasmic sperm injection (ICSI).The FF samples were acquired from September 2012 to February 2014 from women undergoing private fertility treatment in Rio de Janeiro, Brazil. A total of 196 women who were undergoing ICSI and had different infertility diagnoses were recruited. The FF from each patient (average patient age of 36.3 ± 4.3 years) was collected following puncture of just one follicle with the largest diameter. After ruling out blood contamination by spectrophotometry, 163 patient samples were utilized in the study. In the FF, the progesterone levels were negatively correlated with (a) hydrogen peroxide scavenging capacity (HPSC) (r = −0.294, P < 0.0001), (b) total number of follicles (r = −0.246, P < 0.001) and (c) total number of oocytes punctured (r = −0.268, P = 0.0001). The concentration of serum estradiol exhibited a positive correlation with intrafollicular HPSC (r = 0.165, P = 0.037). Our data indicate that the FF levels of estradiol and progesterone are related to the FF redox status, which is closely associated with the number of oocytes obtained during ICSI procedures.

Prostaglandin E2 affects in vitro maturation of bovine oocytes

The role of prostaglandin E₂ (PGE₂) in the successful resumption of oocyte meiosis and cumulus expansion has been well-documented. However, there remains very little information available on the influence of PGE₂ on other processes that occur during oocyte maturation. In this study, we supplemented a maturation medium with PGE₂ and monitored oocyte quality markers, glucose metabolism, mitochondrial status, oxidative stress, and apoptosis in the cumulus-oocyte complexes (COCs), using a well-established in vitro model of embryo production in cattle. We found that this increased availability of PGE₂ during maturation led to an increase in the expression of genes associated with oocyte competence and improved the quality of blastocysts produced. Prostaglandin E₂ also appeared to stimulate glucose uptake and lactate production in the COCs, both influencing the expression of enzymes involved in glycolysis and the hexosamine biosynthetic pathway. We found that PGE₂ reduced intracellular reactive oxygen species levels, and simultaneously increased glutathione concentration and stimulated antioxidant gene expression in the oocyte. These results indicate that PGE₂ has an important role in the protection of oocytes against oxidative stress. Mitochondrial membrane potential was also improved in PGE₂-treated oocytes, and there was a reduction in the occurrence of apoptosis in the COCs. Promotion of an anti-apoptotic balance in transcription of genes involved in apoptosis was present in both oocytes and the cumulus cells. In summary, PGE₂ could represent a novel autocrine/paracrine player in the mechanisms that can facilitate successful oocyte maturation and oocyte survival in the cow.

The role of stimulation protocol, number of oocytes retrieved with respect to follicular fluid oxidative stress and IVF outcome

The study was conducted on a population of 203 women attending the IVF clinic, Ahmedabad, India, to explore the role of stimulation protocol and the number of oocytes retrieved on oxidative stress in follicular fluid and IVF outcome. Follicular fluid was collected during ovum pick-up to determine the oxidative stress markers: superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), total thiols (TT), l-ascorbic acid (AA), total protein, glutathione S-transferase (GST) and glutathione reductase (GRD). The average number of oocytes retrieved was significantly higher in the women receiving a long GnRH agonist protocol compared to GnRH antagonist protocol while the percentage of women with positive IVF outcome was lower in the long agonist protocol. The level of total thiols was significantly lower in the group of women administered a short agonist protocol. The proportion of ETs carried out and positive IVF outcome were higher following retrieval of an intermediate number of oocytes (6-10 oocytes) compared to a lower (0-5 oocytes) and higher (>10 oocytes) number. Mean glutathione reductase (GRD) activity in follicular fluid was significantly elevated in the intermediate (6-10) and higher (>10) oocyte retrieval groups compared to the lower oocyte retrieval group. Positive IVF outcomes were highest when oocyte retrieval was in the range of 6-10 oocytes, and the level of MDA was lower (1.76 ± 0.13 nmol/ml) as compared to 0-5 and >10 oocytes retrieved groups.

Crocin supplementation during oocyte maturation enhances antioxidant defence and subsequent cleavage rate

The purpose of the present study was to assess the effect of crocin supplementation during oocyte maturation on the antioxidant defence and anti-apoptotic ability and subsequent developmental competence of porcine oocytes. Oocytes were cultured in media containing 0, 300, 400 or 500 µg/ml of crocin. Upon maturation, the maturation rates, reactive oxygen species (ROS) and glutathione (GSH) levels, mRNA expression of genes (SOD, CAT, GPx, Bcl-2, BAX and Caspase3), expression of cleaved caspase3 and subsequent embryo cleavage rates were measured. Results indicated that the maturation rate of the 400 µg/ml group was 86.80% (p < 0.01). The ROS concentration of the 500 µg/ml group was the lowest (p < 0.01). The GSH concentration of the 400 µg/ml group was the highest (p < 0.01). The SOD, CAT and GPx mRNA expression levels were the highest in the 300, 400 and 500 µg/ml groups, respectively, with the expression levels of all genes being significantly higher than that of the control group (p < 0.01). The Bcl-2/BAX mRNA expression ratio in 400 and 500 µg/ml groups significantly higher than other groups and significantly decreased caspase3 expression level (p < 0.01). The expression level of cleaved caspase3 in the 500 µg/ml treatment group was the lowest, significantly lower than that of the control group (p < 0.01). The cleavage rate of the 400 µg/ml group was 62.50% (p < 0.01). These experimental results show that the supplementation of in vitro culture medium with 400 µg/ml of crocin significantly enhanced the antioxidant defence and anti-apoptotic ability and subsequent cleavage rate of porcine embryo.

Effects of vitamin C on the outcome of in vitro fertilization-embryo transfer in endometriosis: A randomized controlled study

OBJECTIVE

This study was performed to investigate the effect of vitamin C (VitC) supplementation on the outcomes of in vitro fertilization-embryo transfer (IVF-ET) in patients with endometriosis (EMs).

METHODS

A total of 280 patients with EMs underwent IVF-ET (VitC treatment group, n=160; VitC non-treatment group, n=120). An additional 150 patients who did not have EMs but underwent IVF-ET (control group) were also enrolled in this study. Superoxide dismutase (SOD), total antioxidant capacity (TAC), malondialdehyde (MDA) and reactive oxygen species (ROS) were measured to determine the role of VitC on oxidative stress markers in serum and follicular fluid (FF).

RESULTS

In total, 245 patients with EMs and 132 patients without EMs underwent successful IVF-ET and follow-up. The serum or FF levels of VitC, SOD, and TAC were lower in the EMs than control group; however, the MDA and ROS levels in serum or FF were higher in the EMs than control group. After 2 months of VitC treatment, the serum VitC levels in serum and FF were significantly increased, while oxidative stress markers were unaffected.

CONCLUSION

Treatment with VitC oral formulation improved the serum and FF levels of VitC but did not affect oxidative stress markers in patients with EMs.

Influence of follicular fluid and cumulus cells on oocyte quality: clinical implications

An equilibrium needs to be established by the cellular and acellular components of the ovarian follicle if developmental competence is to be acquired by the oocyte. Both cumulus cells (CCs) and follicular fluid (FF) are critical determinants for oocyte quality. Understanding how CCs and FF influence oocyte quality in the presence of deleterious systemic or pelvic conditions may impact clinical decisions in the course of managing infertility. Given that the functional integrities of FF and CCs are susceptible to concurrent pathological conditions, it is important to understand how pathophysiological factors influence natural fertility and the outcomes of pregnancy arising from the use of assisted reproduction technologies (ARTs). Accordingly, this review discusses the roles of CCs and FF in ensuring oocyte competence and present new insights on pathological conditions that may interfere with oocyte quality by altering the intrafollicular environment.

Metabolic Effects of FecB Gene on Follicular Fluid and Ovarian Vein Serum in Sheep (Ovis aries)

The FecB gene has been discovered as an important gene in sheep for its high relationship with the ovulation rate, but its regulatory mechanism remains unknown. In the present study, liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) techniques were adopted to detect the metabolic effects of FecB gene in follicular fluid (FF) and ovarian vein serum (OVS) in Small Tail Han (STH) sheep. ANOVA and random forest statistical methods were employed for the identification of important metabolic pathways and biomarkers. Changes in amino acid metabolism, redox environment, and energy metabolism were observed in FF from the three FecB genotype STH ewes. Principal component analysis (PCA) and hierarchical clustering analysis (HCA) showed that metabolic effects of FecB gene are more pronounced in FF than in OVS. Therefore, the difference of the metabolic profile in FF is also affected by the FecB genotypes. In Spearman correlation analysis, key metabolites (e.g., glucose 6-phosphate, glucose 1-phosphate, aspartate, asparagine, glutathione oxidized (GSSG), cysteine-glutathione disulfide, γ-glutamylglutamine, and 2-hydrosybutyrate) in ovine FF samples showed a significant correlation with the ovulation rate. Our findings will help to explain the metabolic mechanism of high prolificacy ewes and benefit fertility identification.

Advanced oxidation protein products from the follicular microenvironment and their role in infertile women with endometriosis

Endometriosis (EM) is associated with oxidative stress. Advanced oxidation protein products (AOPPs) are novel markers of oxidative stress, which serve an important role as an inflammatory mediator in various chronic diseases. In order to examine the role of AOPPs in infertile women with EM, the present study analyzed the levels of AOPPs, estradiol (E₂) and progesterone (P₄) in the follicular fluid (FF) of 89 women with or without EM undergoing in vitro fertilization (IVF). The AOPP concentration in the FF of the EM group was significantly higher when compared with that of the control group (51.5±22.4 vs. 41.8±18.3 µmol/l; P<0.05). However, the FF P₄ levels and blastocyst rate were significantly lower in the EM group compared with the control group (P₄:1,249.6±465.4 vs. 1,752.7±565.4 ng/ml, P<0.05; blastocyst rate: 0.511±0.322 vs. 0.662±0.278; P<0.05). The AOPP concentration and P₄ level in the FF presented a significant negative correlation in the EM and control groups, as well as in the total cohort of patients (EM group: r=-0.406, P=0.006; control group: r=-0.315, P=0.035; total: r=-0.421, P<0.001). In addition, there was a significant negative correlation between the FF AOPP concentrations and blastocyst rate in the EM group and in the total cohort (EM group: r=-0.376, P=0.012; total: r=-0.367, P<0.001). In conclusion, these results suggested that AOPPs may be a potentially effective marker for predicting the oocyte quality and outcomes of IVF in infertile women with EM.

Follicular Fluid redox involvement for ovarian follicle growth

As the human ovarian follicle enlarges in the course of a regular cycle or following controlled ovarian stimulation, the changes in its structure reveal the oocyte environment composed of cumulus oophorus cells and the follicular fluid (FF).

In contrast to the dynamic nature of cells, the fluid compartment appears as a reservoir rich in biomolecules. In some aspects, it is similar to the plasma, but it also exhibits differences that likely relate to its specific localization around the oocyte. The chemical composition indicates that the follicular fluid is able to detect and buffer excessive amounts of reactive oxygen species, employing a variety of antioxidants, some of them components of the intracellular milieu.

An important part is played by albumin through specific cysteine residues. But the fluid contains other molecules whose cysteine residues may be involved in sensing and buffering the local oxidative conditions. How these molecules are recruited and regulated to intervene such process is unknown but it is a critical issue in reproduction.

In fact, important proteins in the FF, that regulate follicle growth and oocyte quality, exhibit cysteine residues at specific points, whose untoward oxidation would result in functional loss. Therefore, preservation of controlled oxidative conditions in the FF is a requirement for the fine-tuned oocyte maturation process. In contrast, its disturbance enhances the susceptibility to the establishment of reproductive disorders that would require the intervention of reproductive medicine technology.

Melatonin Scavenger Properties against Oxidative and Nitrosative Stress: Impact on Gamete Handling and In Vitro Embryo Production in Humans and Other Mammals

Oxidative and nitrosative stress are common problems when handling gametes in vitro. In vitro development in mammalian embryos is highly affected by culture conditions, especially by reactive oxygen species (ROS) and reactive nitrogen species (RNS), because their absence or overproduction causes embryo arrest and changes in gene expression. Melatonin in gamete co-incubation during in vitro fertilization (IVF) has deleterious or positive effects, depending on the concentration used in the culture medium, demonstrating the delicate balance between antioxidant and pro-oxidant activity. Further research is needed to better understand the possible impact of melatonin on the different IVP steps in humans and other mammals, especially in seasonal breeds where this neuro-hormone system highly regulates its reproduction physiology.

MECHANISMS IN ENDOCRINOLOGY: Nutrition as a mediator of oxidative stress in metabolic and reproductive disorders in women

Nutrition can generate oxidative stress and trigger a cascade of molecular events that can disrupt oxidative and hormonal balance. Nutrient ingestion promotes a major inflammatory and oxidative response at the cellular level in the postprandial state, altering the metabolic state of tissues. A domino of unfavorable metabolic changes is orchestrated in the main metabolic organs, including adipose tissue, skeletal muscle, liver and pancreas, where subclinical inflammation, endothelial dysfunction, mitochondrial deregulation and impaired insulin response and secretion take place. Simultaneously, in reproductive tissues, nutrition-induced oxidative stress can potentially violate delicate oxidative balance that is mandatory to secure normal reproductive function. Taken all the above into account, nutrition and its accompanying postprandial oxidative stress, in the unique context of female hormonal background, can potentially compromise normal metabolic and reproductive functions in women and may act as an active mediator of various metabolic and reproductive disorders.

Equilibrium between anti-oxidants and reactive oxygen species: a requisite for oocyte development and maturation

Reactive oxygen species (ROS) are required for cellular functioning and are controlled by anti‐oxidants. The ROS influence the follicles, oocytes, endometrium, and their environment. The luteinizing hormone surge initiates a massive recruitment of ROS that modulates major reproductive functions namely, oocyte maturation, ovarian steroidogenesis, corpus luteal function, and luteolysis. The anti‐oxidant system balances ROS generation and maintains the cellular functions. Both enzymatic and non‐enzymatic anti‐oxidants namely, vitamins and minerals are present in the follicles and protect the oocytes from the damaging effects of ROS. The overproduction of ROS leads to oxidative stress that affects the quality of oocytes and subsequent anovulation. Although researchers have tried to establish the role of ROS and anti‐oxidants in oocyte development, still this aspect needs to be revisited. This review discusses the importance of the ROS and anti‐oxidant balance that is required for the development and maturation of oocytes. There are increasing data on the activity of ROS and anti‐oxidants in supporting oocyte development and maturation. However, extensive research is required to identify the safe physiological concentration and duration of both the ROS and anti‐oxidants that are required to facilitate oocyte development and maturation during in vitro and in vivo conditions.

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.

A Mixture Reflecting Polybrominated Diphenyl Ether (PBDE) Profiles Detected in Human Follicular Fluid Significantly Affects Steroidogenesis and Induces Oxidative Stress in a Female Human Granulosa Cell Line

Brominated flame retardants are incorporated into consumer products to prevent flame propagation. These compounds leach into the domestic environment, resulting in chronic exposure. Pregnancy failure is associated with high levels of polybrominated diphenyl ethers (PBDEs), a major class of brominated flame retardants, in human follicular fluid, raising serious questions regarding their impact on female fertility. Our goal was to elucidate the effects of a mixture of PBDEs, similar to the profile found in human follicular fluid, on an immortalized human granulosa cell line, the KGN cell line. We showed that cell viability was altered and oxidative stress was induced as reflected by increased reactive oxygen species formation at 100 μM of the PBDE mixture. Transcriptomic analysis revealed that PBDE treatments of 1, 5, and 20 μM altered the expression of several genes involved in the reactive oxygen species signaling pathway. Significant dose-dependent reductions in progesterone and estradiol levels in the culture medium were measured after PBDE treatment; in parallel, the expression of genes involved in estradiol metabolism, namely CYP1A1, was up-regulated by 5 and 20 μM of the PBDE mixture. Treatment with 20 μM PBDE also increased the expression and secretion of the proinflammatory factor, IL-6, into the KGN cell culture medium. Our results demonstrate that PBDEs can alter human granulosa cell functions by inducing oxidative stress and disrupting steroidogenesis. These results indicate that PBDEs may be detrimental to ovarian functions and thus may adversely affect female reproductive health after chronic exposure.

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.

An Update on Oxidative Damage to Spermatozoa and Oocytes

On the one hand, reactive oxygen species (ROS) are mandatory mediators for essential cellular functions including the function of germ cells (oocytes and spermatozoa) and thereby the fertilization process. However, the exposure of these cells to excessive levels of oxidative stress by too high levels of ROS or too low levels of antioxidative protection will render these cells dysfunctional thereby failing the fertilization process and causing couples to be infertile. Numerous causes are responsible for the delicate bodily redox system being out of balance and causing disease and infertility. Many of these causes are modifiable such as lifestyle factors like obesity, poor nutrition, heat stress, smoking, or alcohol abuse. Possible correctable measures include foremost lifestyle changes, but also supplementation with antioxidants to scavenge excessive ROS. However, this should only be done after careful examination of the patient and establishment of the individual bodily antioxidant needs. In addition, other corrective measures include sperm separation for assisted reproductive techniques. However, these techniques have to be carried out very carefully as they, if applied wrongly, bear risks of generating ROS damaging the germ cells and preventing fertilization.

Aging and the environment affect gamete and embryo potential: can we intervene?

Optimal maturation of the oocyte depends on its environment and determines embryo competence, because the embryonic genome is not active until the cleavage stage and new mitochondria are not produced until blastulation. Adverse environmental factors include aging, andropause, oxidative stress, obesity, smoking, alcohol, and psychologic stress, whereas androgen supplementation, a prudent diet, exercise, nutritional supplements, and psychologic interventions have beneficial effects. Mitochondrial function and energy production deteriorate with age, adversely affecting ovarian reserve, chromosome segregation, and embryo competence. In aging mice, the mitochondrial cofactor coenzyme Q10 reverses most of these changes. Early human experience has been encouraging, although only a small study using a shorter duration of intervention compared with the murine model has been carried out. Mitochondrial metabolic stress can result in an abnormal compensatory increase in mitochondrial DNA, which can be assessed in biopsied blastomeres of trophectoderm as a predictive biomarker of implantation failure. Psychologic stress may reduce oocyte competence by shifting blood flow away from the ovary as part of the classic "fight or flight" physiologic response, and methods to reduce stress or the body's reaction to stress improve pregnancy success. Enhancing oocyte competence is a key intervention that promises to reduce the number of euploid embryos failing to produce viable deliveries.

Expression Levels of the Oxidative Stress Response Gene ALDH3A2 in Granulosa-Lutein Cells Are Related to Female Age and Infertility Diagnosis

Oxidative stress (OS) plays an important role in all physiological processes. The effect of OS on cellular processes is modulated by the ability of the cell to express genes implicated in the reversal of lipid, protein, and DNA injury. Aldehyde dehydrogenase 3, member A2 (ALDH3A2) is a ubiquitous enzyme involved in lipid detoxification. The objective of this study was to investigate the expression ofALDH3A2in human granulosa-lutein (GL) cells of women undergoing in vitro fertilization (IVF) and its relationship with age, infertility diagnosis, and IVF outcome variables. Relative expression levels ofALDH3A2were determined by quantitative reverse transcription-polymerase chain reaction. To investigate the effect of age onALDH3A2expression, 72 women between 18 and 44 years of age with no ovarian factor (NOF) were analyzed. To evaluate the effect of infertility diagnosis onALDH3A2expression, the following groups were analyzed: 22 oocyte donors (ODs), 24 women >40 years old (yo) with tubal or male factor and no ovarian pathology, 18 poor responders (PRs), 19 cases with endometriosis (EM), and 18 patients with polycystic ovarian syndrome (PCOS). In NOF,ALDH3A2expression correlated positively with age and with the doses of follicle-stimulating hormone and luteinizing hormone administered and negatively with the number of total and mature oocytes. When different groups were analyzed,ALDH3A2expression levels were higher in patients >40 yo and in PR compared to OD. On the contrary, EM and PCOS levels were lower than expected for age. These data suggest that GL cellALDH3A2expression levels correlate with age, cause of infertility, and ovarian response to stimulation.

Oocyte environment: follicular fluid and cumulus cells are critical for oocyte health

Bidirectional somatic cell-oocyte signaling is essential to create a changing intrafollicular microenvironment that controls primordial follicle growth into a cohort of growing follicles, from which one antral follicle is selected to ovulate a healthy oocyte. Such intercellular communications allow the oocyte to determine its own fate by influencing the intrafollicular microenvironment, which in turn provides the necessary cellular functions for oocyte developmental competence, which is defined as the ability of the oocyte to complete meiosis and undergo fertilization, embryogenesis, and term development. These coordinated somatic cell-oocyte interactions attempt to balance cellular metabolism with energy requirements during folliculogenesis, including changing energy utilization during meiotic resumption. If these cellular mechanisms are perturbed by metabolic disease and/or maternal aging, molecular damage of the oocyte can alter macromolecules, induce mitochondrial mutations, and reduce adenosine triphosphate production, all of which can harm the oocyte. Recent technologies are now exploring transcriptional, translational, and post-translational events within the human follicle with the goal of identifying biomarkers that reliably predict oocyte quality in the clinical setting.

Utility of antioxidants during assisted reproductive techniques: an evidence based review

Assisted reproductive technology (ART) is a common treatment of choice for many couples facing infertility issues, be it due to male or female factor, or idiopathic. Employment of ART techniques, however, come with its own challenges as the in vitro environment is not nearly as ideal as the in vivo environment, where reactive oxygen species (ROS) build-up leading to oxidative stress is kept in check by the endogenous antioxidants system. While physiological amounts of ROS are necessary for normal reproductive function in vivo, in vitro manipulation of gametes and embryos exposes these cells to excessive ROS production either by endogenous or exogenous environmental factors. In this review, we discuss the sources of ROS in an in vitro clinical setting and the influence of oxidative stress on gamete/embryo quality and the outcome of IVF/ICSI. Sources of ROS and different strategies of overcoming the excessive generation of ROS in vitro are also highlighted. Endogenously, the gametes and the developing embryo become sources of ROS. Multiple exogenous factors act as potential sources of ROS, including exposure to visible light, composition of culture media, pH and temperature, oxygen concentration, centrifugation during spermatozoa preparation, ART technique involving handling of gamete/embryo and cryopreservation technique (freeze/thawing process). Finally, the use of antioxidants as agents to minimize ROS generation in the in vitro environment and as oral therapy is highlighted. Both enzymatic and non-enzymatic antioxidants are discussed and the outcome of studies using these antioxidants as oral therapy in the male or female or its use in vitro in media is presented. While results of studies using certain antioxidant agents are promising, the current body of evidence as a whole suggests the need for further well-designed and larger scale randomized controlled studies, as well as research to minimize oxidative stress conditions in the clinical ART setting.

Melatonin: shedding light on infertility?--A review of the recent literature

In recent years, the negative impact of oxidative stress on fertility has become widely recognised. Several studies have demonstrated its negative effect on the number and quality of retrieved oocytes and embryos following in-vitro fertilisation (IVF). Melatonin, a pineal hormone that regulates circadian rhythms, has also been shown to exhibit unique oxygen scavenging abilities. Some studies have suggested a role for melatonin in gamete biology. Clinical studies also suggest that melatonin supplementation in IVF may lead to better pregnancy rates. Here we present a critical review and summary of the current literature and provide suggestions for future well designed clinical trials.

SIRT3 positively regulates the expression of folliculogenesis- and luteinization-related genes and progesterone secretion by manipulating oxidative stress in human luteinized granulosa cells

SIRT3 is a member of the sirtuin family and has recently emerged as a vital molecule in controlling the generation of reactive oxygen species (ROS) in oocytes. Appropriate levels of ROS play pivotal roles in human reproductive medicine. The aim of the present study was to investigate SIRT3 expression and analyze the SIRT3-mediated oxidative response in human luteinized granulosa cells (GCs). Human ovarian tissues were subjected to immunohistochemical analysis to localize SIRT3 expression. Hydrogen peroxide and human chorionic gonadotropin were used to analyze the relationship between ROS and SIRT3 by quantitative RT-PCR and Western blotting. Intracellular levels of ROS were investigated by fluorescence after small interfering RNA-mediated knockdown of SIRT3 in human GCs. To uncover the role of SIRT3 in folliculogenesis and luteinization, mRNA levels of related genes and the progesterone concentration were analyzed by quantitative RT-PCR and immunoassays, respectively. We detected the expression of SIRT3 in the GCs of the human ovary. The mRNA levels of SIRT3, catalase, and superoxide dismutase 1 were up-regulated by hydrogen peroxide in both COV434 cells and human GCs and down-regulated by human chorionic gonadotropin. Knockdown of SIRT3 markedly elevated ROS generation in human GCs. In addition, SIRT3 depletion resulted in decreased mRNA expression of aromatase, 17β-hydroxysteroid dehydrogenase 1, steroidogenic acute regulatory protein, cholesterol side-chain cleavage enzyme, and 3β-hydroxysteroid dehydrogenase in GCs and thus resulted in decreased progesterone secretion. These results have the important clinical implication that SIRT3 might play a positive role in the folliculogenesis and luteinization processes in GCs, possibly by sensing and regulating the generation of ROS. Activation of SIRT3 function might help to sustain human reproduction by maintaining GCs as well as oocytes.

Influence of ovarian stimulation for IVF/ICSI on the antioxidant defence system and relationship to outcome

Ovarian stimulation is used with IVF/intracytoplasmic sperm injection (ICSI) cycles to obtain multiple oocytes and improve pregnancy rates; however, it also induces perturbation in the oxidant-antioxidant balance leading to oxidation stress. The present study monitored the plasma antioxidant status in women undergoing a long agonist protocol of ovarian stimulation at three different time points: at baseline (T0), after pituitary suppression (T1) and on the day of oocyte retrieval (T2). The antioxidant composition of follicular fluid samples collected on T2 was also evaluated. Significant decreases (P < 0.05) of plasma vitamin C, vitamin E and carotenoids were found between T1 and T2 but not between T0 and T1. At T2, high plasma vitamin E was associated with high numbers of total and mature oocytes retrieved per patient, which, in turn, were favourable for achieving pregnancy. Accordingly, women who became pregnant presented higher vitamin E concentrations both in plasma and FF than those who did not. In conclusion, this study confirmed the occurrence of significant modifications of the plasma antioxidant profile during ovarian stimulation with gonadotrophins; at the same time, it was found that both systemic and follicular antioxidant status may be related to IVF/ICSI outcome.

Elevated blood plasma antioxidant status is favourable for achieving IVF/ICSI pregnancy

The aim of the study was to determine the roles of intrafollicular and systemic oxidative stress and antioxidant response in ovarian stimulation and intracytoplasmic sperm injection (ICSI) outcomes. For this purpose, 102 ICSI patients undergoing controlled ovarian stimulation were enrolled and samples were collected on the day of follicle puncture. Total peroxide (TPX) concentrations and total antioxidant response (TAR) were measured in follicular fluid and blood plasma, and an oxidative stress index (OSI) was calculated based on these two parameters. Urinary concentrations of 8-iso-prostaglandin F2a (F2IsoP) were measured. Elevated intrafollicular oxidative stress was positively correlated with ovarian stimulation outcome: less FSH per retrieved oocyte was used, more oocytes were collected and higher serum oestradiol concentrations were measured in patients with higher follicular OSI. However, high urinary F2IsoP related to lower embryo quality and F2IsoP was also elevated in smoking patients. Patients with endometriosis had lower follicular antioxidant status. Most importantly, higher systemic blood TAR was significantly favourable for achieving clinical pregnancy (P=0.03). In conclusion, the findings suggest clear associations between oxidative stress, antioxidant status and several aspects of ovarian stimulation and IVF/ICSI outcome, including pregnancy rate. Several oxygen-dependent biochemical reactions produce reactive oxygen species as by-products that may eventually lead to oxidative stress, which is detrimental to cells and tissues. Total antioxidant status, on the other hand, comprises several agents that balance the excess of these reactive oxygen species and reduce potential damage to the body. The aim of the current work was to study this balance in 102 patients participating in an ICSI programme and to examine the degree to which total peroxide content and antioxidant status influence infertility and pregnancy outcome. During the study, several tests were performed to characterize oxidative stress levels in ovarian follicular fluid, blood plasma and urine. We found a significantly higher oxidative stress environment in the ovary when compared with blood plasma. This suggests a prominent role of oxidative stress in the ovaries of these patients. The elevated oxidative stress levels were correlated to a higher number of oocytes that could be obtained via the procedure and to a lower amount of FSH needed to mature the oocytes, suggesting that oxidative stress, to some degree, is favourable for hormone stimulation outcome. A high level of lipid peroxidation products in the urine, another marker of oxidative stress, was observed in smokers and this marker was elevated in patients with embryos that had lower developmental potential. A higher overall antioxidant status in blood plasma was advantageous for achieving pregnancy.

Metabolite Profiling in the Pursuit of Biomarkers for IVF Outcome: The Case for Metabolomics Studies

Background. This paper presents the literature on biomarkers of in vitro fertilisation (IVF) outcome, demonstrating the progression of these studies towards metabolite profiling, specifically metabolomics. The need for more, and improved, metabolomics studies in the field of assisted conception is discussed. Methods. Searches were performed on ISI Web of Knowledge SM for literature associated with biomarkers of oocyte and embryo quality, and biomarkers of IVF outcome in embryo culture medium, follicular fluid (FF), and blood plasma in female mammals. Results. Metabolomics in the field of female reproduction is still in its infancy. Metabolomics investigations of embryo culture medium for embryo selection have been the most common, but only within the last five years. Only in 2012 has the first metabolomics investigation of FF for biomarkers of oocyte quality been reported. The only metabolomics studies of human blood plasma in this context have been aimed at identifying women with polycystic ovary syndrome (PCOS). Conclusions. Metabolomics is becoming more established in the field of assisted conception, but the studies performed so far have been preliminary and not all potential applications have yet been explored. With further improved metabolomics studies, the possibility of identifying a method for predicting IVF outcome may become a reality.

The relationship between pregnancy and oxidative stress markers on patients undergoing ovarian stimulations

PURPOSE

We investigated the activities and relevance of a validated panel of antioxidant enzymes, cytokines, specific lipid peroxidation end products and six fatty acids by correlational analyses with peak E(2) levels and pregnancy outcome after ovarian stimulation for IVF or IUI.

METHODS

Blood samples obtained from 15 patients undergoing ovarian stimulation with rFSH or hMG were divided into two groups. Group-1 was baseline blood collected on day-2-3 of women cycle. Group-2 is blood collected at the end of FSH/hMG injection. Serum was collected and stored in liquid nitrogen at -196 °C until analysis. Standard IVF and IUI procedures were followed. The serum levels of Paraoxonase (PON1), Superoxide Dismutases (SOD), Interleukin-6 (IL-6), Glutathione Peroxidase (GPx), 8-Isoprostane, and fatty acids Arachidic, Palmitic, Stearic, Oleic, Linoleic & Linolenic were measured.

RESULTS

With the exception of 8-Isoprostane, results showed a positive correlation between baseline and peak levels of E(2) and that of SOD, GPx, PON1, and IL-6. The PON1, IL-6 and SOD were significantly (p < 0.05) higher in pregnant than non-pregnant group. Fatty acid levels at baseline and peak E(2) were not different but pregnancy rates were found to be decreasing with higher palmitic, and stearic acid levels.

CONCLUSIONS

Ovarian stimulation causes a significant increase in serum PON1, SOD, GPx and IL-6 activity in women undergoing IVF or IUI. The high levels of IL-6, SOD, and PON1 and lower levels of palmitic, and stearic acids in the pregnancy positive group indicate that these oxidative stress and nutritional factors may be used as a predictive marker in controlled ovarian stimulation success.