Novel follicular fluid factors influencing oocyte developmental potential in IVF: a review

Unraveling the complexity of follicular fluid: insights into its composition, function, and clinical implications

Follicular fluid (FF) plays a vital role in the bidirectional communication between oocytes and granulosa cells (GCs), regulating and promoting oocyte growth and development. This fluid constitutes a complex microenvironment, rich in various molecules including hormones, growth factors, cytokines, lipids, proteins, and extracellular vesicles. Understanding the composition and metabolic profile of follicular fluid is important for investigating ovarian pathologies such as polycystic ovary syndrome (PCOS) and endometriosis. Additionally, analyzing follicular fluid can offer valuable insights into oocyte quality, aiding in optimal oocyte selection for in vitro fertilization (IVF). This review provides an overview of follicular fluid composition, classification of its components and discusses the influential components of oocyte development. It also highlights the role of follicular fluid in the pathogenesis and diagnosis of ovarian diseases, along with potential follicular fluid biomarkers for assessing oocyte quality. By understanding the intricate relationship between follicular fluid and oocyte development, we can advance fertility research and improve clinical outcomes for infertility patients.

Astaxanthin improves assisted reproductive technology outcomes in poor ovarian responders through alleviating oxidative stress, inflammation, and apoptosis: a randomized clinical trial

BACKGROUND

Poor ovarian response (POR) to controlled ovarian stimulation (COS) remains challenging, especially in advanced-age women with diminished ovarian reserve, resulting in low live birth rates. Many patients prefer to conceive with their eggs, underscoring the need for improved treatments. This study explores astaxanthin potential as a COS adjuvant to improve ovarian response and assisted reproductive technology (ART) outcomes, considering its impact on oxidative stress (OS), inflammation, and apoptosis, which are key factors in POR.

METHODS

In this randomized, triple-blind, placebo-controlled trial, 60 infertile POR patients from POSEIDON Group 4 (the poorest prognosis category, age > 35 and poor ovarian reserve (anti-müllerian hormone < 1.2 ng/ml or antral follicle count < 5) undergoing intracytoplasmic sperm injection were enrolled. Patients were assigned to receive either 12 mg/day AST or placebo for eight weeks. All patients underwent a gonadotropin-releasing hormone antagonist regimen for COS. ART outcomes were compared between groups. Blood serum and follicular fluid (FF) were analyzed for OS markers (superoxide dismutase [SOD], total antioxidant capacity [TAC], and malondialdehyde [MDA]), and pro-inflammatory cytokines (interleukin-6 [IL-6], interleukin-8 [IL-8], and vascular endothelial growth factor [VEGF]) via enzyme-linked immunosorbent assay kits, and cell-free DNA [cfDNA] (apoptotic marker) via ALU quantitative polymerase chain reaction.

RESULTS

After the intervention, the AST group exhibited a significant elevation in serum (P = 0.013) and TAC (P = 0.030), accompanied by a significant reduction in serum MDA (P = 0.005). No significant differences between AST and placebo groups were observed in OS markers in FF. AST group showed significant reductions in the serum IL-6 (P < 0.001), IL-8 (P = 0.001), and VEGF (P = 0.002) levels following AST therapy. In the AST group, FF levels of IL-6 (P = 0 < 001), IL-8 (P = 0.036), VEGF (P = 0.006), and cfDNA (P < 0.001) were significantly lower than in the placebo group. Between-group comparisons showed significant differences in the alterations of serum SOD (P = 0.027), IL-6 (P < 0.001), and IL-8 (P = 0.035) levels between AST and placebo groups. The AST group showed significant increases in the number of retrieved oocytes (P = 0.003), MII oocytes (P = 0.004), frozen embryos (P = 0.037), and high-quality embryos (P = 0.014) compared to the placebo group.

CONCLUSION

AST shows promise as a COS adjuvant therapy, potentially enhancing some ART outcomes in POR through alleviating OS, inflammation, and apoptosis.

TRIAL REGISTRATION

Clinical trial registration number: IRCT20230223057510N1, URL: https://irct.behdasht.gov.ir/trial/68870 , registration date: 2023 March 16.

Increased serum IL-12 levels are associated with adverse IVF outcomes

Interleukin-12 (IL-12) is involved in the occurrence and development of many diseases, such as preeclampsia, intrauterine growth restriction, preterm labor, and recurrent pregnancy losses. This study aimed to determine whether a high serum level of IL-12 was associated with adverse in vitro fertilization (IVF) outcomes. Included infertile women with high serum IL-12 levels who underwent IVF cycles and infertile controls with pure tubal etiology. The impact of serum IL-12 on baseline and clinical characteristics, immune-related indicators, IVF laboratory, and pregnancy outcomes were compared. In addition, the correlation of follicular fluid IL-12 and serum IL-12 level and the role of IL-12 in apoptosis of granulosa cells (GCs) was investigated. Women with high serum IL-12 levels had lower numbers of retrieved oocytes, embryos, perfect and available embryos, lower rates of perfect and available embryos, and blastocyst formation. Additionally, significantly higher levels of serum Th1, Th2, and Th17-related cytokines were observed in women with high serum IL-12 levels than in the controls. Meanwhile, the follicular fluid IL-12 levels were positively correlated with serum IL-12 levels, and IL-12 promoted apoptosis of GCs in vitro. We concluded that women with serum high IL-12 levels may have adverse IVF outcomes, partly by promoting apoptosis of GCs. Therefore, early screening for cytokines, especially IL-12, and appropriate consultation for couples receiving IVF-ET should be considered. In addition, specific immune and inflammatory mechanisms associated with high serum IL-12 levels should be further explored.

The Ratio of cf-mtDNA vs. cf-nDNA in the Follicular Fluid of Women Undergoing IVF Is Positively Correlated with Age

Age-related mitochondrial markers may facilitate the prognosis of artificial reproductive technology outcomes. In this report, we present our study concerning the ratio of cf-mtDNA/cf-nDNA, namely the amount of cell-free mitochondrial DNA relative to cell-free nuclear DNA, in the follicular fluid (FF) of women undergoing IVF, aiming to generate a molecular fingerprint of oocyte quality. The values of this ratio were measured and compared among three groups of women (101 in total): (A) 31 women with polycystic ovary syndrome (PCOS), (B) 34 women younger than 36 years, and (C) 36 women older than 35 years of age. Real-time quantitative PCR (qPCR) was performed to quantify the ratio by using nuclear- and mitochondrial-specific primers and analyzed for potential correlation with age and pregnancy rate. Our analysis showed that the level of FF-cf-mtDNA was lower in the group of advanced-age women than in the groups of PCOS and non-PCOS women. Moreover, a significant positive correlation between FF-cf-mtDNA and the number of mature (MII) oocytes was observed. Collectively, the data show that the relative ratio of cf- mtDNA to cf-nDNA content in human FF can be an effective predictor for assessing the corresponding oocyte's age-related performance in IVF.

Effects of Follicular Fluid on Physiological Characteristics and Differentiation of Fallopian Tube Epithelial Cells Implicating for Ovarian Cancer Pathogenesis

The fallopian tube (FT) is an important reproductive organ in females. Ample evidence suggests that the distal end of FT is the original site of high-grade serous ovarian carcinoma (HGSC). FT may suffer from repeated injury and repair stimulated by follicular fluid (FF); however, this hypothesis has not been examined. In fact, the molecular mechanism of homeostasis, differentiation, and the transformation of fallopian tube epithelial cells (FTECs) resulting from the stimulation of FF are still enigmatic. In this study, we examined the effects of FF along with factors present in the FF on a variety of FTEC models, including primary cell culture, ALI (air-liquid interface) culture, and 3D organ spheroid culture. We found that FF plays a similar role to estrogen in promoting cell differentiation and organoid formation. Moreover, FF significantly promotes cell proliferation and induces cell injury and apoptosis in high concentrations. These observations may help us to investigate the mechanisms of the initiation of HGSC.

Cell-Free DNA as a New Biomarker of IVF Success, Independent of Any Infertility Factor, Including Endometriosis

Cell-free DNA fragments detected in blood and in other biological fluids are released from apoptotic/necrotic cells. In this study, we analyzed cfDNA levels in follicular fluid (FF) samples from patients with infertility. Samples were collected from 178 infertile women and cfDNA was extracted and quantified by qPCR, using ALU115 and ALU247 primers, and statistical correlations were performed. We found that cfDNA concentration was significantly higher in FF pools from women aged 35 and over than in women under 35 years of age (p = 0.017). We also found that q247 cfDNA levels were significantly higher in women with an associated female factor, such as endometriosis, PCOS and POF, compared with women with no specific cause of infertility (p = 0.033). The concentration of cfDNA did not vary significantly in each group of women with an associated female factor. The concentration of cfDNA was significantly higher in the FF of women that obtained embryos with a high fragmentation rate, compared to embryos with a low fragmentation rate (p = 0.007). Finally, we found that women who did not become pregnant during IVF treatments had higher q247 cfDNA levels (p = 0.043). The quantification of cfDNA could be an important biomarker of follicular micro-environment quality to predict embryo quality and the success of IVF, making them more specific and effective.

Therapeutic effect of Ferula assa-foetida oleo-gum resin in rats with letrozole-induced polycystic ovary syndrome

OBJECTIVE

Asafoetida is a gum derived from Ferula assa-foetida, which is used in traditional Iranian medicine to treat some reproductive system disorders. The effects of asafoetida on ovarian tissue, expression of certain genes associated with polycystic ovary syndrome (PCOS), and levels of liver, kidney, and blood cell factors after treatment in a rat model were investigated.

METHODS

Thirty rats were divided into five groups: normal, polycystic, and treatment with three doses of asafoetida (12.5, 25, and 50 mg/kg for 3 weeks after PCOS induction). PCOS was induced by letrozole at a dose of 1 mg/kg administered orally for 3 weeks. Blood samples were taken, and the ovaries were removed and prepared for histomorphometric examination. Liver and kidney parameters were measured. The mRNA expression levels of luteinizing hormone receptor, CYP11A1, adenosine monophosphate-activated protein kinase, adiponectin, and adiponectin receptors 1 and 2 were also measured by real-time polymerase chain reaction.

RESULTS

The levels of liver, kidney, and blood parameters did not significantly differ between the treatment groups and the control group. At doses of 25 and 50 mg/kg, ovarian histopathology, especially the thicknesses of the theca and granulosa layers, was significantly improved relative to the PCOS group. The expression of target genes also improved in the 25 and 50 mg/kg treatment groups.

CONCLUSION

Asafoetida can be used to treat PCOS as a complementary approach to conventional therapies. Asafoetida appears to act by regulating and activating metabolic and ovarian cycle enzymes.

PCOS Physiopathology and Vitamin D Deficiency: Biological Insights and Perspectives for Treatment

Recent literature has stressed the importance of vitamin D (VD) in polycystic ovary syndrome (PCOS). Women with PCOS are deficient in VD, particularly those with a higher weight. Hypovitaminosis is a risk factor for glucose intolerance, and reduced levels of VD is associated with insulin resistance and increased diabetes risk. Since women with PCOS and hirsutism seem to have lower levels of VD than women with PCOS without hirsutism, a correlation between VD deficiency and hyperandrogenism may be suggested. Interestingly, VD is crucial for many human physiological functions, including to counteract inflammation and oxidative stress. Some studies evaluated effects of VD supplementation on glucose homeostasis variables, hormonal status, lipid concentrations, and biomarkers of inflammation and oxidative stress among VD-deficient women. Moreover, VD has been shown to play a role in egg quality and fertility. This review aims to show the relationship between VD and the endocrine and metabolic profile of PCOS patients, as well as its implications for their fertility. The supplement of VD to the common therapy can lead to an improvement of the insulin resistance and lipid metabolism, a reduction of circulating androgens, as well as a better response to the induction of ovulation in PCOS women.

Electroacupuncture improves follicular development and metabolism and regulates the expression of adiponectin, AMPK and ACC in an obese rat model of polycystic ovary syndrome

BACKGROUND

Polycystic ovary syndrome (PCOS) is a common endocrine disorder characterized by hyperandrogenism and follicular arrest. Electroacupuncture (EA) has been shown to be effective at improving hyperandrogenism and follicular arrest in PCOS; however, its mechanism of action remains to be deciphered.

OBJECTIVE

In this study, we investigated whether EA improved follicular development in an obese rat model of PCOS and regulated the expression of adiponectin, AMP-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC).

METHODS

EA was administered at CV3, CV4 and ST40. Changes in body weight, paraovarian fat, estrus cycle, ovarian morphology, levels of related hormones, and glucose and lipid metabolism were evaluated. In addition, protein and mRNA expression of adiponectin, AMPK and ACC was measured.

RESULTS

The body weight and paraovarian fat of rats in the EA group were reduced, while estrus cyclicity and ovarian morphology improved. Levels of free fatty acids, triglycerides, total cholesterol and low-density lipoprotein cholesterol were significantly reduced in the EA group, as well as blood glucose levels. Furthermore, levels of testosterone and luteinizing hormone were reduced in the EA group, while estradiol levels were increased. Protein and mRNA expression of adiponectin, AMPKα1 and liver kinase B1 (LKB1) was found to be increased in the EA group, while protein and mRNA expression of ACC were significantly reduced.Conclusion: Our findings suggest that EA improved follicular development and metabolism and regulated expression levels of adiponectin, AMPKα1, LKB1 and ACC in our obese rat model of PCOS.

Consecutive versus concomitant follicle-stimulating hormone and highly purified human menopausal gonadotropin: A milder response but better quality

Objective

This study investigated the impact of two stimulation protocols using highly purified human menopausal gonadotropin (HP-hMG) on the endocrine profile, follicular fluid soluble Fas levels, and outcomes of intracytoplasmic sperm injection (ICSI) cycles.

Methods

This prospective clinical trial included 100 normal-responder women undergoing ovarian stimulation for ICSI; 55 patients received concomitant follicle-stimulating hormone (FSH) plus HP-hMG from the start of stimulation, while 45 patients received FSH followed by HP-hMG during mid/late follicular stimulation. The primary outcome was the number of top-quality embryos. The secondary outcomes were the number and percentage of metaphase II (MII) oocytes and the clinical pregnancy rate.

Results

The number of MII oocytes was significantly higher in the concomitant protocol (median, 13.0; interquartile range [IQR], 8.5–18.0 vs. 9.0 [8.0–13.0] in the consecutive protocol; p=0.009); however, the percentage of MII oocytes and the fertilization rate were significantly higher in the consecutive protocol (median, 90.91; IQR, 80.0–100.0 vs. 83.33 [75.0–93.8]; p=0.034 and median, 86.67; IQR, 76.9–100.0 vs. 77.78 [66.7–89.9]; p=0.028, respectively). No significant between-group differences were found in top-quality embryos (p=0.693) or the clinical pregnancy rate (65.9% vs. 61.8% in the consecutive vs. concomitant protocol, respectively). The median follicular fluid soluble Fas antigen level was significantly higher in the concomitant protocol (9,731.0 pg/mL; IQR, 6,004.5–10,807.6 vs. 6,350.2 pg/mL; IQR, 4,382.4–9,418.4; p=0.021).

Conclusion

Personalized controlled ovarian stimulation using HP-hMG during the late follicular phase led to a significantly lower response, but did not affect the quality of ICSI.

Cell-free DNA in Human Follicular Fluid as Biomarker for Intracytoplasmic Sperm Injection Procedure Outcome

Background: Follicular fluid considered as an important microenvironment for oocyte development, cell free-DNA (cfDNA) fragments that are found in this fluid and are released from cell apoptosis and/or necrosis, aimed to quantified the level of cf-DNA, in the follicular fluid and to assess any relation between the level of cf-DNA in this fluid with women’s age, duration of infertility, cause of infertility, her ovarian reserve values. Methods: Eighty-nine women were prospectively included in this study FF cf-DNA which was determined by conventional real time PCR-syber green detection approach which quantified by ALU-specific primers. Results: cell-free DNA (cfDNA) level in Follicular fluid samples of Iraqi women level was; cfDNA (Mean±SD, 0.916±0.106 ng/μl). there was no significant relation between cfDNA and pregnancy outcome, but very low level and very high level cf DNA were related to negative pregnancy outcome, cfDNA was second most important predictive factor of pregnancy outcome after fertilization rate, but both not statistically significant p value was (0.622 and 0.241) respectively. Conclusion: current study notice that cfDNA in the follicular fluid may mainly reflect the cellular activity and the balance between programed apoptosis and cell necrosis.

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

RESEARCH QUESTION

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

DESIGN

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

RESULTS

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

CONCLUSIONS

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

Hypo-glycosylated hFSH drives ovarian follicular development more efficiently than fully-glycosylated hFSH: enhanced transcription and PI3K and MAPK signaling

STUDY QUESTION

Does hypo-glycosylated human recombinant FSH (hFSH18/21) have greater in vivo bioactivity that drives follicle development in vivo compared to fully-glycosylated human recombinant FSH (hFSH24)?

SUMMARY ANSWER

Compared with fully-glycosylated hFSH, hypo-glycosylated hFSH has greater bioactivity, enabling greater follicular health and growth in vivo, with enhanced transcriptional activity, greater activation of receptor tyrosine kinases (RTKs) and elevated phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) and Mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) signaling.

WHAT IS KNOWN ALREADY

Glycosylation of FSH is necessary for FSH to effectively activate the FSH receptor (FSHR) and promote preantral follicular growth and formation of antral follicles. In vitro studies demonstrate that compared to fully-glycosylated recombinant human FSH, hypo-glycosylated FSH has greater activity in receptor binding studies, and more effectively stimulates the PKA pathway and steroidogenesis in human granulosa cells.

STUDY DESIGN, SIZE, DURATION

This is a cross-sectional study evaluating the actions of purified recombinant human FSH glycoforms on parameters of follicular development, gene expression and cell signaling in immature postnatal day (PND) 17 female CD-1 mice. To stimulate follicle development in vivo, PND 17 female CD-1 mice (n = 8-10/group) were treated with PBS (150 µl), hFSH18/21 (1 µg/150 µl PBS) or hFSH24 (1 µg/150 µl PBS) by intraperitoneal injection (i.p.) twice daily (8:00 a.m. and 6:00 p.m.) for 2 days. Follicle numbers, serum anti-Müllerian hormone (AMH) and estradiol levels, and follicle health were quantified. PND 17 female CD-1 mice were also treated acutely (2 h) in vivo with PBS, hFSH18/21 (1 µg) or hFSH24 (1 µg) (n = 3-4/group). One ovary from each mouse was processed for RNA sequencing analysis and the other ovary processed for signal transduction analysis. An in vitro ovary culture system was used to confirm the relative signaling pathways.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The purity of different recombinant hFSH glycoforms was analyzed using an automated western blot system. Follicle numbers were determined by counting serial sections of the mouse ovary. Real-time quantitative RT-PCR, western blot and immunofluorescence staining were used to determine growth and apoptosis markers related with follicle health. RNA sequencing and bioinformatics were used to identify pathways and processes associated with gene expression profiles induced by acute FSH glycoform treatment. Analysis of RTKs was used to determine potential FSH downstream signaling pathways in vivo. Western blot and in vitro ovarian culture system were used to validate the relative signaling pathways.

MAIN RESULTS AND THE ROLE OF CHANCE

Our present study shows that both hypo- and fully-glycosylated recombinant human FSH can drive follicular growth in vivo. However, hFSH18/21 promoted development of significantly more large antral follicles compared to hFSH24 (P < 0.01). In addition, compared with hFSH24, hFSH18/21 also promoted greater indices of follicular health, as defined by lower BAX/BCL2 ratios and reduced cleaved Caspase 3. Following acute in vivo treatment with FSH glycoforms RNA-sequencing data revealed that both FSH glycoforms rapidly induced ovarian transcription in vivo, but hypo-glycosylated FSH more robustly stimulated Gαs and cAMP-mediated signaling and members of the AP-1 transcription factor complex. Moreover, hFSH18/21 treatment induced significantly greater activation of RTKs, PI3K/AKT and MAPK/ERK signaling compared to hFSH24. FSH-induced indices of follicle growth in vitro were blocked by inhibition of PI3K and MAPK.

LARGE SCALE DATA

RNA sequencing of mouse ovaries. Data will be shared upon reasonable request to the corresponding author.

LIMITATIONS, REASONS FOR CAUTION

The observations that hFSH glycoforms have different bioactivities in the present study employing a mouse model of follicle development should be verified in nonhuman primates. The gene expression studies reflect transcriptomes of whole ovaries.

WIDER IMPLICATIONS OF THE FINDINGS

Commercially prepared recombinant human FSH used for ovarian stimulation in human ART is fully-glycosylated FSH. Our findings that hypo-glycosylated hFSH has greater bioactivity enabling greater follicular health and growth without exaggerated estradiol production in vivo, demonstrate the potential for its development for application in human ART.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by NIH 1P01 AG029531, NIH 1R01 HD 092263, VA I01 BX004272, and the Olson Center for Women's Health. JSD is the recipient of a VA Senior Research Career Scientist Award (1IK6 BX005797). This work was also partially supported by National Natural Science Foundation of China (No. 31872352). The authors declared there are no conflicts of interest.

Metabolomic Profiling of Pregnancies With Polycystic Ovary Syndrome Identifies a Unique Metabolic Signature and Potential Predictive Biomarkers of Low Birth Weight

BACKGROUND

Polycystic ovary syndrome (PCOS) is a complex syndrome with clinical features of an endocrine/metabolic disorder. Various metabolites show significant association with PCOS; however, studies comparing the metabolic profile of pregnant women with and without PCOS are lacking. In this study, metabolomics analysis of blood samples collected from PCOS women and age and BMI matched controls in the second trimester of pregnancy was performed to identify metabolic differences between the two groups and determine their association with pregnancy outcome.

METHODS

Sixteen PCOS and fifty-two healthy women in their second trimester underwent targeted metabolomics of plasma samples using tandem mass spectrometry with the Biocrates MxP^® Quant 500 Kit. Linear regression models were used to identify the metabolic alterations associated with PCOS, followed by enrichment and Receiver Operating Characteristic (ROC) analyses to determine the best indicators of pregnancy outcomes.

RESULTS

PCOS women had lower birth weight babies compared to healthy controls. As a group, systolic blood pressure (SBP) at both second trimester and at delivery negatively correlated with birth weight. Regression models indicated significant increases in the triglycerides C20:4_C34:3 and C18:2_C38:6 in the PCOS group [false discovery rate (FDR) <0.05]. Enrichment analysis revealed significant elevations in triglycerides containing arachidonic acid, linoleic acid and palmitic acid in the PCOS group. A number of indicators of baby birth weight were identified including SBP at delivery, hexosylceramide (d18:2/24:0), ceramide (d18.0/24.1) and serine, with an AUC for all predictors combined for low birth weight (≤2500grams) of 0.88 (95%CI: 0.75-1.005, p<0.001).

CONCLUSIONS

PCOS pregnancies resulted in babies with a lower birth weight, marked by a unique metabolic signature that was enriched with specific triglycerides and unsaturated fatty acids. The functional significance of these associations needs further investigation.

Seminal cell-free DNA and sperm characteristic's: An added biomarker for male infertility investigation

Cell-free DNA (Cf-DNA) fragments may constitute an easy-to-measure molecular tool for guiding the choice of care provided to infertile couples who benefit assisted reproductive technology (ART) programmes. Data on Cf-DNA levels in the seminal plasma of men with sperm alterations are scarce. The objective of the present study was to quantify the presence of Cf-DNA in semen by using a quantitative real-time PCR. We compared men with abnormal sperm characteristics (n = 21) with normospermic controls (n = 21). The PCR assay evidenced significantly higher mean Cf-DNA levels in patients with sperm abnormalities than in controls (2.09 versus 1.18 µg/ml, respectively; p = .0003). The Cf-DNA levels were notably higher in men with azoospermia (3.65 µg/ml, versus 1.34 µg/ml in matched controls; p = .03) and men with teratozoospermia (1.80 µg/ml, versus 1.29 µg/ml in matched controls; p = .008). Our data report a significant association between elevated Cf-DNA levels and sperm abnormalities. These results may open up new diagnostic and prognostic perspectives in male infertility.

Restraint stress of male mice induces apoptosis in spermatozoa and spermatogenic cells: role of the FasL/Fas system†

The mechanisms by which psychological stress impairs semen quality are largely unknown. By using a restraint-stressed mouse model, we studied the role of the FasL/Fas system in psychological stress-induced apoptosis of spermatozoa and spermatogenic cells. Male mice were restrained for 48 h before examination for sperm fertilizing potential and for apoptosis and FasL/Fas expression in spermatozoa, spermatogenetic cells/seminiferous tubules, and caudae epididymides. The results showed that the male restraint reduced motility, fertilization rates, and mitochondrial membrane potential while increasing apoptosis and Fas expression in spermatozoa. Restraint also facilitated apoptosis and FasL/Fas expression in spermatogenic cells/seminiferous tubules and caudae epididymides. The restraint-induced apoptosis in spermatozoa and spermatogenic cells was significantly ameliorated in gld mice that harbor a loss-of-function mutation in FasL. However, incubation with FasL did not affect sperm motility and apoptosis, while incubation with tumor necrosis factor (TNF)-α did. The epididymis of the gld mice produced significantly less TNF-α and TNF-related apoptosis-inducing ligand (TRAIL) than that of wild-type mice did after male restraint. Thus, the results confirmed that the FasL/Fas system played an important role in the psychological stress-induced apoptosis of spermatozoa and spermatogenic cells and that FasL triggered sperm apoptosis in epididymis dependently through promoting TNF-α and TRAIL secretion.

Bovine Follicular Fluid and Extracellular Vesicles Derived from Follicular Fluid Alter the Bovine Oviductal Epithelial Cells Transcriptome

While follicular fluid (FF) is well known to provide an optimal environment for oogenesis, its functional roles following its release into the oviduct during ovulation are currently elusive. We hypothesized that FF and FF-derived extracellular vesicles (EVs) may be conveyors of signals capable of inducing functionally-relevant transcriptional responses in oviductal cells. The aim of this study was, therefore, to evaluate the effect of FF and FF-derived EVs on the transcriptome of primary bovine oviductal epithelial cells (BOECs). We examined the gene expression of BOECs in three conditions: BOECs cultured with FF, FF-derived EVs, and without supplementations. For each condition, cells were cultured for 6 and 24 h. RNA sequencing results revealed that FF had a stronger effect on BOECs gene expression compared to EVs. We detected 488 and 1998 differentially expressed genes (DEGs) with FF treatment in 6 and 24 h, respectively, whereas only 41 DEGs were detected at 6 h following EV treatment. Pathway analysis of the FF-induced DEGs showed that several pathways were highly enriched, notably oxidative phosphorylation, thermogenesis, arachidonic acid metabolism, and steroid hormone biosynthesis. Some of these pathways have a role in sperm survival, fertilization, and early embryo development. In conclusion, the findings of our study demonstrate for the first time that bovine FF and FF-derived EVs can induce changes in the gene expression of the bovine oviductal cells which, although observed in vitro, may be reflective of in vivo responses which may contribute to a favorable periconceptional microenvironment for sperm survival, fertilization, and early embryo development.

Expression of Matrix Metalloproteinases and Their Inhibitors in Endometrium: High Levels in Endometriotic Lesions

Endometriosis is a condition defined as presence of endometrium outside of the uterine cavity. These endometrial cells are able to attach and invade the peritoneum or ovary, thus forming respectively the deep infiltrating endometriosis (DIE) and the ovarian endometrioma (OMA), the ectopic lesions feature of this pathology. Endometriotic cells display high invasiveness and share some features of malignancy with cancer cells. Indeed, the tissue remodeling underlining lesion formation is achieved by matrix metalloproteinases (MMPs) and their inhibitors. Therefore, these molecules are believed to play a key role in development and pathogenesis of endometriosis. This study investigated the molecular profile of metalloproteinases and their inhibitors in healthy (n = 15) and eutopic endometrium (n = 19) in OMA (n = 10) and DIE (n = 9); moreover, we firstly validated the most reliable housekeeping genes allowing accurate gene expression analysis in these tissues. Gene expression, Western blot, and immunofluorescence analysis of MMP2, MMP3, and MMP10 and their tissue inhibitors TIMP1 and TIMP2 demonstrated that these enzymes are finely tuned in these tissues. In OMA lesions, all the investigated MMPs and their inhibitors were significantly increased, while DIE expressed high levels of MMP3. Finally, in vitro TNFα treatment induced a significant upregulation of MMP3, MMP10, and TIMP2 in both healthy and eutopic endometrial stromal cells. This study, shedding light on MMP and TIMP expression in endometriosis, confirms that these molecules are altered both in eutopic endometrium and endometriotic lesions. Although further studies are needed, these data may help in understanding the molecular mechanisms involved in the extracellular matrix remodeling, a crucial process for the endometrial physiology.

Mass Spectrometric Analysis of L-carnitine and its Esters: Potential Biomarkers of Disturbances in Carnitine Homeostasis

PURPOSE

After a golden age of classic carnitine research three decades ago, the spread of mass spectrometry opened new perspectives and a much better understanding of the carnitine system is available nowadays. In the classic period, several human and animal studies were focused on various distinct physiological functions of this molecule and these revealed different aspects of carnitine homeostasis in normal and pathological conditions. Initially, the laboratory analyses were based on the classic or radioenzymatic assays, enabling only the determination of free and total carnitine levels and calculation of total carnitine esters' amount without any information on the composition of the acyl groups. The introduction of mass spectrometry allowed the measurement of free carnitine along with the specific and sensitive determination of different carnitine esters. Beyond basic research, mass spectrometry study of carnitine esters was introduced into the newborn screening program because of being capable to detect more than 30 metabolic disorders simultaneously. Furthermore, mass spectrometry measurements were performed to investigate different disease states affecting carnitine homeostasis, such as diabetes, chronic renal failure, celiac disease, cardiovascular diseases, autism spectrum disorder or inflammatory bowel diseases.

RESULTS

This article will review the recent advances in the field of carnitine research with respect to mass spectrometric analyses of acyl-carnitines in normal and various pathological states.

CONCLUSION

The growing number of publications using mass spectrometry as a tool to investigate normal physiological conditions or reveal potential biomarkers of primary and secondary carnitine deficiencies shows that this tool brought a new perspective to carnitine research.

Cumulus cell-released tumor necrosis factor (TNF)-α promotes post-ovulatory aging of mouse oocytes

Although previous studies indicated that cumulus cells (CCs) accelerate oocyte aging by releasing soluble factors, the factors have yet to be characterized. While demonstrating that CCs promoted oocyte aging by releasing soluble Fas ligand (sFasL), our recent study suggested that CCs might secrete other factors to mediate oocyte aging as well. This study tested whether CCs accelerate oocyte aging by secreting tumor necrosis factor (TNF)-α. The results showed that mouse CCs undergoing apoptosis released soluble TNF-α (sTNF-α) during in vitro aging. While ethanol activation rates were higher, the maturation-promoting factor (MPF) activity was lower significantly after culture of cumulus-denuded oocytes (DOs) in medium conditioned with CCs for 36 h than in medium conditioned for 24 h. Aging mouse oocytes expressed TNF-receptor 1. The CCs released equal amounts of sTNF-α and sFasL during aging in vitro, and the TNF-α-knockdown CCs secreted less sFasL than the control CCs did. Treatment of DOs in vitro with sTNF-α significantly accelerated their aging. The aging-promoting effect of sTNF-α was significantly reduced in TNF-α-knocked-down CCs and in CCs from the TNF-α-knockout mice. It is concluded that mouse CCs accelerate oocyte aging by secreting sTNF-α as well as sFasL.

Body mass index in relation to extracellular vesicle-linked microRNAs in human follicular fluid

OBJECTIVE

To study whether increased body mass index is associated with altered expression of extracellular vesicle microRNAs (EV-linked miRNAs) in human follicular fluid.

DESIGN

Cross-sectional study.

SETTING

Tertiary-care university-affiliated center.

PATIENT(S)

One hundred thirty-three women undergoing in vitro fertilization (IVF) were recruited from January 2014 to August 2016.

INTERVENTIONS(S)

None.

MAIN OUTCOME MEASURE(S)

EV-linked miRNAs were isolated from follicular fluid and their expression profiles were measured with the use of the Taqman Open Array Human miRNA panel. EV-linked miRNAs were globally normalized and inverse-normal transformed. Associations between body mass index (BMI) and EV-linked miRNA outcomes were analyzed by means of multivariate linear regression and principal component analysis.

RESULT(S)

Eighteen EV-linked miRNAs were associated with an increase in BMI after adjusting for age, ethnicity, smoking status, and batch effects. Hsa-miR-328 remained significant after false discovery rate adjustments. Principal component analyses identified the first principal component to account for 40% of the variation in our EV-linked miRNA dataset, and adjusted linear regression found that the first principal component was significantly associated with BMI after multiple testing adjustments. Using Kyoto Encyclopedia of Genes and Genomes enrichment analyses, we predicted gene targets of EV-linked miRNA in silico and identified PI3K-Akt signaling, ECM-receptor interaction, focal adhesion, FoxO signaling, and oocyte meiosis pathways.

CONCLUSION(S)

These results show that a 1-unit increase in BMI is associated with altered follicular fluid expression of EV-linked miRNAs that may influence follicular and oocyte developmental pathways. Our findings provide potential insight into a mechanistic explanation for the reduced fertility rates associated with increased BMI.

Identification of potential metabolic biomarkers of polycystic ovary syndrome in follicular fluid by SWATH mass spectrometry

BACKGROUND

Polycystic ovary syndrome (PCOS) is a complex disorder associated with multiple metabolic disturbance, including defective glucose metabolism and insulin resistance. The altered metabolites caused by the related metabolic disturbance may affect ovarian follicles, which can be reflected in follicular fluid composition. The aim of this study is to investigate follicular fluid metabolic profiles in women with PCOS using an advanced sequential window acquisition of all theoretical fragment-ion spectra (SWATH) mass spectrometry.

MATERIALS AND METHODS

Nineteen women with PCOS and twenty-one healthy controls undergoing IVF/ET were recruited, and their follicular fluid samples were collected for metabolomic study. Follicular fluid metabolic profiles, including steroid hormones, free fatty acids, bioactive lipids, and amino acids were analyzed using the principal component analysis (PCA) and partial least squares to latent structure-discriminant analysis (PLS-DA) model.

RESULTS

Levels of free fatty acids, 3-hydroxynonanoyl carnitine and eicosapentaenoic acid were significantly increased (P < 0.05), whereas those of bioactive lipids, lysophosphatidylcholines (LysoPC) (16:0), phytosphingosine, LysoPC (14:0) and LysoPC (18:0) were significantly decreased in women with PCOS (P < 0.05). Additionally, levels of steroid hormone deoxycorticosterone and two amino acids, phenylalanine and leucine were higher in the PCOS patients (P < 0.05).

CONCLUSION

Women with PCOS display unique metabolic profiles in their follicular fluid, and this data may provide us with important biochemical information and metabolic signatures that enable a better understanding of the pathogenesis of PCOS.

Matrix metalloproteinases and their inhibitors in human cumulus and granulosa cells as biomarkers for oocyte quality estimation

OBJECTIVE

To study the molecular profile of metalloproteinases and their tissue inhibitors in granulosa and cumulus cells in a subset of fertile and infertile women.

DESIGN

Molecular study with granulosa and cumulus cells.

SETTING

University hospital.

PATIENT(S)

Forty-four women undergoing assisted reproductive techniques for female infertility factor, with partners having a normal spermiogram and 15 normally fertile women with male partner affected by severe oligoasthenoteratozoospermia or nonobstructive azoospermia.

INTERVENTION(S)

In vitro fertilization.

MAIN OUTCOME MEASUREMENT(S)

We investigated gene expression level of metalloproteinases (MMP2, MMP9, MMP11) and their tissue inhibitors (TIMP1, TIMP2) by means of quantitative reverse-transcription polymerase chain reaction, protein quantification by means of Western blot, and localization by means of immunofluorescence.

RESULT(S)

We firstly validated HPRT1 as the most reliable housekeeping gene enabling correct gene expression analysis in both granulosa and cumulus cells. Gene expression, Western blot, and immunofluorescence analysis of MMP2, MMP9, and MMP11 and their tissue inhibitors TIMP1 and TIMP2 demonstrated that these enzymes are finely tuned in these cells. MMP9 is specifically expressed only in granulosa, whereas MMP2 is more expressed in cumulus and granulosa cells in cases of reduced ovarian response and decreased fertilization rate.

CONCLUSION(S)

This study sheds light on MMP and TIMP expression in granulosa and cumulus cells, and it may help in understanding the fine regulation of oocyte maturation inside the follicle. Although further studies are needed to fully understand the molecular mechanisms involved in these processes, our findings may be useful in the identification of biomarkers of oocyte maturation, competence acquiring, and fertilization.

Synergy of Paracrine Signaling During Early-Stage Mouse Ovarian Follicle Development In Vitro

Introduction

Paracrine signals, such as soluble cytokines and extracellular matrix cues, are essential for the survival and development of multicellular ovarian follicles. While it is well established that hydrogel-based culture systems successfully support the growth of late-stage follicles for fertility preservation, growing small, early-stage ovarian follicles still proves to be challenging. We hypothesized that paracrine factors secreted from neighboring follicles may be crucial for improving the survival of early-stage follicles in vitro.

Methods

To test our hypothesis, we investigated the bi-directional crosstalk of the paracrine signals, such as cell-secreted cytokines, sex hormones and transcription factors (TFs), in follicles encapsulated and cultured for 12 days in alginate in groups of five (5×) and ten (10×).

Results

The differential profiles of TF activity and secretome during folliculogenesis were analyzed using TRanscriptional Activity CEllular aRray (TRACER) and data-driven multivariate modeling approach. The mechano- and oxygen-responsive TFs, NF-κB and HIF1, exhibited a unique upregulation signature in 10× follicles. Consistently, levels of proangiogenic factors, such as VEGF-A and angiopoietin-2, were significantly higher in 10× follicles than those in 5× follicles, reaching 269.77 and 242.82 pg/mL on the last day of culture. The analysis of TRACER and secreted cytokines also revealed critical early interactions between cytokines and TFs, correlating with the observed phenotypical and functional differences between conditions.

Conclusions

We identified unique signatures of synergism during successful early-stage ovarian follicle development. These findings bring us closer to understanding of mechanisms underlying the downstream effects of interactions between the extracellular microenvironment and early-stage folliculogenesis in vitro.

Alterations of polyunsaturated fatty acid metabolism in ovarian tissues of polycystic ovary syndrome rats

The metabolism of polyunsaturated fatty acids (PUFAs) remains poorly characterized in ovarian tissues of patients with polycystic ovary syndrome (PCOS). This study aimed to explore alterations in the levels of PUFAs and their metabolites in serum and ovarian tissues in a PCOS rat model treated with a high‐fat diet and andronate. Levels of PUFAs and their metabolites were measured using gas/liquid chromatography‐mass spectrometry after the establishment of a PCOS rat model. Only 3 kinds of PUFAs [linoleic acid, arachidonic acid (AA) and docosahexaenoic acid] were detected in both the circulation and ovarian tissues of the rats, and their concentrations were lower in ovarian tissues than in serum. Moreover, significant differences in the ovarian levels of AA were observed between control, high‐fat diet‐fed and PCOS rats. The levels of prostaglandins, AA metabolites via the cyclooxygenase (COX) pathway, in ovarian tissues of the PCOS group were significantly increased compared to those in the controls. Further studies on the mechanism underlying this phenomenon showed a correlation between decreased expression of phosphorylated cytosolic phospholipase A2 (p‐cPLA2) and increased mRNA and protein expression of COX2, potentially leading to a deeper understanding of altered AA and prostaglandin levels in ovarian tissues of PCOS rats.

Multiple reaction monitoring (MRM)-profiling for biomarker discovery applied to human polycystic ovarian syndrome

RATIONALE

We describe multiple reaction monitoring (MRM)-profiling, which provides accelerated discovery of discriminating molecular features, and its application to human polycystic ovary syndrome (PCOS) diagnosis. The discovery phase of the MRM-profiling seeks molecular features based on some prior knowledge of the chemical functional groups likely to be present in the sample. It does this through use of a limited number of pre-chosen and chemically specific neutral loss and/or precursor ion MS/MS scans. The output of the discovery phase is a set of precursor/product transitions. In the screening phase these MRM transitions are used to interrogate multiple samples (hence the name MRM-profiling).

METHODS

MRM-profiling was applied to follicular fluid samples of 22 controls and 29 clinically diagnosed PCOS patients. Representative samples were delivered by flow injection to a triple quadrupole mass spectrometer set to perform a number of pre-chosen and chemically specific neutral loss and/or precursor ion MS/MS scans. The output of this discovery phase was a set of 1012 precursor/product transitions. In the screening phase each individual sample was interrogated for these MRM transitions. Principal component analysis (PCA) and receiver operating characteristic (ROC) curves were used for statistical analysis.

RESULTS

To evaluate the method's performance, half the samples were used to build a classification model (testing set) and half were blinded (validation set). Twenty transitions were used for the classification of the blind samples, most of them (N = 19) showed lower abundances in the PCOS group and corresponded to phosphatidylethanolamine (PE) and phosphatidylserine (PS) lipids. Agreement of 73% with clinical diagnosis was found when classifying the 26 blind samples.

CONCLUSIONS

MRM-profiling is a supervised method characterized by its simplicity, speed and the absence of chromatographic separation. It can be used to rapidly isolate discriminating molecules in healthy/disease conditions by tailored screening of signals associated with hundreds of molecules in complex samples.

Protocol for Exosome Isolation from Small Volume of Ovarian Follicular Fluid: Evaluation of Ultracentrifugation and Commercial Kits

The ovarian follicular fluid (FF) is a complex fluid that constitutes the microenvironment of developing follicles and contains factors secreted by the surrounding cells and blood plasma compounds that cross the "blood-follicle barrier." Upon oocyte retrieval (in human, bovine, and equine) the follicular fluid is normally discarded and represents a repertoire of cellular messages exchanged during follicle development, thus providing a suitable sample for performing oocyte quality diagnostics. Several studies report on the presence of extracellular vesicles (EVs) in FF from human, bovine and equine. Here, we describe the process of FF collection from human and bovine and the enrichment and isolation of EVs that we termed folliculosomes (FFEs), using available commercial kits as well as the traditional ultracentrifugation methods.

Cell-free DNA induced apoptosis of granulosa cells by oxidative stress

BACKGROUND

Cell-free DNA is a DNA fragment that is produced by cell apoptosis which can affect the micro-environment of cell apoptosis. The levels of Cell-free DNA have been associated with successful rate of in vitro fertilization-embryo transfer (IVF-ET) and embryonic development. Our aim is to determine the relationship between cell-free DNA and embryo quality. The mechanisms of cell-free DNA in granulose and the apoptosis will be determined also.

METHODS

The study enrolled patients who were undergone IVF for the first time and grouped the patients as pregnant (n=130) and non-pregnant (n=59). The relationship was determined by statistical analysis between the levels of cell-free DNA in the follicular fluid and clinical data of IVF patients. Flow cytometry was done to detect the rate of granulosa cell apoptosis and intracellular reactive oxygen species (ROS) level. Western blotting and fluorescent quantitative PCR detected the apoptosis-related gene expressions.

RESULTS

Clinical data statistics showed that cell-free DNA levels were positively correlated with granulosa cell apoptosis and negatively correlated with embryo quality and pregnancy rates. High levels of cell-free DNA lead to increased ROS in granulosa cells and activated caspase through Fas/FasL that induced apoptosis.

CONCLUSION

High levels of cell-free DNA triggers granulosa cell apoptosis and influences oocyte maturation embryo development and pregnancy rates in IVF treatments. Cell-free DNA can be as a secondary criteria and predictive marker for the quality control of IVF embryo.

Moderate increase of reactive oxygen species triggers meiotic resumption in rat follicular oocytes

AIM

The mammalian ovary generates reactive oxygen species (ROS) on an extraordinary scale; however, the role of ROS during meiotic cell cycle progression in follicular oocytes remains poorly understood. The present study was aimed to determine whether a moderate increase of ROS level in the ovary is beneficial for meiotic resumption from diplotene arrest in follicular oocytes.

METHODS

Cumulus oocyte complexes were collected from the ovaries of female rats that had been treated with either: (i) pregnant mare's serum gonadotrophin; or (ii) pregnant mare's serum gonadotrophin + human chorionic gonadotrophin. We analyzed morphological changes, ROS and hydrogen peroxide levels, catalase activity, 3',5'-cyclic adenosine monophosphate and 3',5'-cyclic guanosine monophosphate levels, Thr14/Tyr15, Th-161, total cyclin-dependent kinase 1 (Cdk1) and cyclin B1 levels.

RESULTS

Human chorionic gonadotrophin treatment induced meiotic resumption from diplotene arrest and extrusion of first polar body in cumulus oocyte complexes collected from ovaries and cultured for 3 h in vitro. Meiotic resumption from diplotene arrest was associated with increased ROS and hydrogen peroxide levels but decreased 3',5'-cyclic adenosine monophosphate as well as 3',5'-cyclic guanosine monophosphate levels. The reduced cyclic nucleotide levels were associated with decreased Thr161 phosphorylated Cdk1 and cyclin B1 level but increased Thr14/Tyr15 phosphorylated Cdk1 level leading to maturation promoting factor destabilization. Destabilized maturation-promoting factor triggered meiotic resumption from diplotene arrest and progression to metaphase-I as well as metaphase-II stage in follicular oocytes.

CONCLUSION

Our findings suggest that a moderate increase of ROS in the ovary is beneficial for meiotic resumption from diplotene arrest and extrusion of first polar body in follicular oocytes.

The effect of FT500 Plus(®) on ovarian stimulation in PCOS women

Both oxidative stress and polycystic ovary syndrome have been involved in several aspects of female reproduction. In this retrospective observational study, the outcome of controlled ovarian stimulation and follicular microenvironment of twenty-five women affected by PCOS (Group A) have been explored, evaluating the effects of myo-inositol in association with antioxidant activities (FT500 Plus(®)). Twenty-five untreated-PCOS women (Group B) with similar characteristics served as control group. Although there was no difference in ovarian volume at time zero, this parameter was significantly smaller at the 5-month follow-up in the Group A (11.1±0.9 versus 13.5±1; P=0.0001). Group A showed a significant increase in the number of MII oocytes (6.3±2.5 versus 4.5±2; P=0.03) and glutathione peroxidase activity in follicular fluid (15.4±6.2 versus 11±2.2; P=0.04). FT500 Plus(®) may be considered in PCOS patient for improving oocyte quality.

[Circulating nucleic acids and infertility]

Circulating nucleic acids (cell-free DNA and microRNAs) have for particularity to be easily detectable in the biological fluids of the body. Therefore, they constitute biomarkers of interest in female and male infertility care. Indeed, in female, they can be used to detect ovarian reserve disorders (polycystic ovary syndrome and low functional ovarian reserve) as well as to assess follicular microenvironment quality. Moreover, in men, their expression levels can vary in case of spermatogenesis abnormalities. Finally, circulating nucleic acids have also the ability to predict successfully the quality of in vitro embryo development. Their multiple contributions during assisted reproductive technology (ART) make of them biomarkers of interest, for the development of new diagnostic and/or prognostic tests, applied to our specialty. Circulating nucleic acids would so offer the possibility of personalized medical care for infertile couples in ART.

Cell-free DNA in Human Follicular Microenvironment: New Prognostic Biomarker to Predict in vitro Fertilization Outcomes

Cell-free DNA (cfDNA) fragments, detected in blood and in other biological fluids, are released from apoptotic and/or necrotic cells. CfDNA is currently used as biomarker for the detection of many diseases such as some cancers and gynecological and obstetrics disorders. In this study, we investigated if cfDNA levels in follicular fluid (FF) samples from in vitro fertilization (IVF) patients, could be related to their ovarian reserve status, controlled ovarian stimulation (COS) protocols and IVF outcomes. Therefore, 117 FF samples were collected from women (n = 117) undergoing IVF/Intra-cytoplasmic sperm injection (ICSI) procedure and cfDNA concentration was quantified by ALU-quantitative PCR. We found that cfDNA level was significantly higher in FF samples from patients with ovarian reserve disorders (low functional ovarian reserve or polycystic ovary syndrome) than from patients with normal ovarian reserve (2.7 ± 2.7 ng/μl versus 1.7 ± 2.3 ng/μl, respectively, p = 0.03). Likewise, FF cfDNA levels were significant more elevated in women who received long ovarian stimulation (> 10 days) or high total dose of gonadotropins (≥ 3000 IU/l) than in women who received short stimulation duration (7–10 days) or total dose of gonadotropins < 3000 IU/l (2.4 ± 2.8 ng/μl versus 1.5 ± 1.9 ng/μl, p = 0.008; 2.2 ± 2.3 ng/μl versus 1.5 ± 2.1 ng/μl, p = 0.01, respectively). Finally, FF cfDNA level was an independent and significant predictive factor for pregnancy outcome (adjusted odds ratio = 0.69 [0.5; 0.96], p = 0.03). In multivariate analysis, the Receiving Operator Curve (ROC) analysis showed that the performance of FF cfDNA in predicting clinical pregnancy reached 0.73 [0.66–0.87] with 88% specificity and 60% sensitivity. CfDNA might constitute a promising biomarker of follicular micro-environment quality which could be used to predict IVF prognosis and to enhance female infertility management.

Preconception folic acid use influences the follicle fluid proteome

BACKGROUND

The investigation of the human follicle fluid proteome has gained much interest in the search of new markers as predictors for in vitro fertilization and intracytoplasmic sperm injection (IVF/ICSI) treatment outcome. Follicular fluid folate, as substrate of one carbon (1-C) metabolism, affects follicular metabolism and oocyte and embryo quality. From this background, we aim to identify a folate-related follicle fluid proteome that associates with IVF/ICSI treatment outcome.

METHODS

In a nested case-control study embedded in a periconception cohort, we performed qualitative and quantitative proteomic analyses using nanoflow LC-MS/MS and TMT labelling in 30 monofollicular fluid samples from women undergoing IVF/ICSI treatment of which 15 used and 15 did not use a folic acid supplement. The protein data are analysed using scaffold proteome Software and differential abundances are expressed as Log2-fold change. Blood samples were obtained before and after treatment for determination of biomarkers of 1-C metabolism and estradiol.

RESULTS

We identified 227 uniquely expressed proteins in follicular fluid. In folic acid supplement users compared to nonusers, we established a lower abundance of C-reactive protein (-2.03; P = < 0.01) and higher abundances of apolipoproteins from high-density lipoprotein (HDL), most notably A-I (+1.28; P = < 0.01) and C-I (+1.11; P = 0.016).

CONCLUSION

Preconception folic acid supplement use is associated with suppression of the inflammatory pathway and upregulation of the HDL pathway in human follicular fluid, being a preferential source of cholesterol for steroid hormone synthesis. Studies are needed on the tissue specificity and on the beneficial effects of embryo quality and IVF/ICSI treatment outcome of the proteome of these pathways.

Arachidonic and linoleic acid derivatives impact oocyte ICSI fertilization--a prospective analysis of follicular fluid and a matched oocyte in a 'one follicle--one retrieved oocyte--one resulting embryo' investigational setting

Objective

To evaluate human oocyte ability to undergo fertilization and subsequent preimplantation embryonic development in relation to a wide panel of follicular fluid (FF) arachidonic acid derivatives (AAD) and linoleic acid derivatives (LAD) of prospectively selected patients undergoing intracytoplasmic sperm injection (ICSI).

Methodology

Study was designed as a two center (a university clinic and a private clinic) prospective study. 54 women of 181 consecutive couples undergoing ICSI were prospectively found to be eligible for analysis. 'One follicle – one retrieved oocyte – one resulting embryo' approach was used. Each individual follicle was aspirated independently and matched to an oocyte growing in this particular follicular milieu. FF samples were assessed for AAD and LAD by high-performance liquid chromatography; additionally, activity of secretory phospholipase A (sPLA₂) was determined by enzyme-linked immunosorbent assay.

Principal Findings

Increased activity of sPLA₂ and significantly higher AAD and LAD levels were found in FF of oocytes that did not show two pronuclei or underwent degeneration after ICSI in comparison to oocytes with the appearance of two pronuclei. Receiver operating characteristics curve analysis identified acids with the highest sensitivity and specificity: 5oxo-hydroxyeicosatetraenoic, 16-hydroxyeicosatetraenoic, 9-hydroxyoctadecadieneoic and 12-hydroxyeicosatetraenoic. No significant differences between AAD and LAD related to embryo quality were found.

Conclusions/Significance

Our study demonstrates for the first time that elevated concentrations of AAD and LAD in FF at the time of oocyte retrieval significantly decrease the ability of oocytes to form pronuclei after ICSI. This may serve as a new tool for non-invasive assessment of oocyte developmental capacity. However, levels of AAD and LAD are not associated with subsequent embryo quality or pregnancy rate, and therefore more studies are needed to determine their usefulness in human IVF procedure.

Associations between insulin resistance, free fatty acids, and oocyte quality in polycystic ovary syndrome during in vitro fertilization

CONTEXT

Both polycystic ovary syndrome (PCOS) and obesity are associated with specific reproductive health complications, including lower oocyte quality and clinical pregnancy rates in assisted conception cycles, which may be a result of metabolism-induced changes in the oocyte through the microenvironment of follicular fluid. Free fatty acids (FFAs) are important biomedical indicators of abnormal lipid metabolism and have pronounced effects on cells, leading to changes in metabolism, cell growth, and differentiation.

OBJECTIVE

Our objective was to determine the effect of FFA metabolism in plasma and follicular fluid on oocyte quality in the women with PCOS undergoing in vitro fertilization.

DESIGN AND SETTING

Ninety-three women undergoing in vitro fertilization treatment, including 55 with PCOS and 38 age-matched controls, were recruited. PCOS patients were divided into obese and nonobese subgroups on the basis of their body mass index.

MAIN OUTCOME MEASURES

Embryo quality was morphologically assessed, and serum sex hormone and insulin levels were measured. FFAs in plasma and follicular fluid were measured using gas chromatography-mass spectrometry.

RESULTS

PCOS was found to be associated with significantly higher LH/FSH, total T, free androgen index (FAI), and lower SHBG levels, independent of obesity(P < .05). Obese women with PCOS had a significantly higher total T level, FAI, fasting insulin, insulin resistance index as determined by homeostasis model assessment for insulin resistance, and lower SHBG levels than the nonobese women with PCOS (P < .05). The embryo fragmentation score was significantly positively correlated with the oleic acid concentration in all PCOS patients (r = 0.22, P = .04, for nonobese patients and r = 0.25, P = .03, for obese patients).

CONCLUSIONS

Our findings clearly demonstrated that PCOS is associated with significantly higher FAI and insulin resistance levels and decreased plasma SHBG levels, independent of body mass index. Obese PCOS patients had higher palmitoleic acid and oleic acid levels in both the plasma and follicular fluid than did the control subject and nonobese PCOS patients. Our results indicated that developmental competence is associated with oleic and stearic acid concentrations, which may contribute to the poor pregnancy outcomes in patients with PCOS.

Follicular fluid oocyte/cumulus-free DNA concentrations as a potential biomolecular marker of embryo quality and IVF outcome

The present prospective study examined the follicular fluid oocyte/cumulus-free DNA concentrations (ff o/c-free DNA) during ovarian stimulation and the possible association between ff o/c-free DNA and embryological results such as embryo quality and pregnancy rate. Eighty-three women undergoing IV/ICSI-ET treatments were prospectively included in this study. ff o/c-free DNA was determined by conventional quantitative real time PCR-Sybr green detection approach. The 83 ff samples were categorized in two groups: group 1 (n = 62) with cumulus oocytes complexes (CoCs) ≥2 and group 2 (n = 21) with CoCs = 1. Group 1 revealed significant higher embryo quality in terms of mean score of embryo transfer (MSET), but lower ff o/c-free DNA concentrations compared to group 2. The two groups showed comparable pregnancy rates (positive hCG and clinical pregnancy). The higher the ff o/c-free DNA concentration, the lower the number of produced oocytes. ff o/c-free DNA did not seem to have any direct role in the IVF outcome. Further research is required to clarify whether ff o/c-free DNA is a biomolecular marker of embryo quality and IVF outcome.

Follicular fluid leptin concentrations and expression of leptin and leptin receptor in the equine ovary and in vitro-matured oocyte with reference to pubertal development and breeds

There is no published information about follicular-fluid leptin concentrations or the presence of leptin and leptin receptor in the equine ovary or oocyte. Three groups of mares - adult draft mares, draft fillies and adult Standardbred mares - were included in the study. Leptin and leptin receptor were detected in all immature oocytes by immunofluorescence with higher intensity in oocytes from draft mares compared with draft fillies and Standardbred mares. After in vitro maturation a higher proportion of oocytes reached metaphase II in draft mares than in draft fillies and Standardbred mares, and in all groups both leptin and leptin receptor became localised in the oocyte cortex but with higher immunopositivity in draft mares compared with draft fillies and Standardbred mares. These intensities were confirmed by the expression profiles of leptin and leptin receptor mRNA. Moreover, leptin was detected in ovarian blood vessels in all three types of animal and within the corpora lutea in adult mares. Serum and follicular-fluid concentrations of leptin were similar in draft and Standardbred mares but higher in draft mares than in draft fillies. This study supports the hypothesis that expression of leptin and leptin receptor mRNA and the rate of maturation can be related either to adiposity or to puberty.

Acylcarnitine esters profiling of serum and follicular fluid in patients undergoing in vitro fertilization

BACKGROUND

L-carnitine-mediated beta-oxidation of fatty acids has a well established role in energy supply of oocytes and embryos. Disturbed carnitine metabolism may impair the reproductive potential in IVF and can serve as a biomarker of pregnancy outcome.

METHODS

Our study was performed between March 24, 2011 and May 9, 2011. We performed 44 unselected IVF cycles, (aged 23-40 years (mean: 32.3+/-5.1 years) and had BMI of 17.3-34.7 (mean: 23.80+/-4.9). Samples were also obtained from 18 healthy women of similar age admitted for minor elective surgery to serve as control for plasma carnitine profile. Serum and follicular fluid (FF) free carnitine (FC) and 20 major acylcarnitines (ACs) were measured by ESI/MS/MS method.

RESULTS

Serum FC and AC levels in IVF patients were comparable to those in healthy control women. In FF FC and short-chain AC concentrations were similar to those in maternal serum, however, the levels of medium-chain, and long-chain AC esters were markedly reduced (p<0.05). The serum to FF ratio of individual carnitine compounds increased progressively with increasing carbon chain length of AC esters (p<0.05). There was a marked reduction in total carnitine, FC and AC levels of serum and FF in patients with oocyte number of >9 and/or with embryo number of >6 as compared to the respective values of <9 and/or <6 (p<0.05).

CONCLUSIONS

In IVF patients with better reproductive potential the carnitine/AC pathway appears to be upregulated that may result in excess carintine consumption and relative depletion of carnitine pool. Consequently, IVF patients may benefit from carnitine supplementation.

Assessment of oocyte quality in polycystic ovarian syndrome and endometriosis by spindle imaging and reactive oxygen species levels in follicular fluid and its relationship with IVF-ET outcome

OBJECTIVES:

The aim of this study is to examine meiotic spindle in oocytes along with reactive oxygen species (ROS) levels in follicular fluid of women undergoing IVF and to correlate these findings with embryo quality and pregnancy outcome.

MATERIALS AND METHODS:

167 women aged 25–35 years with endometriosis (Group A), polycystic ovarian syndrome (PCOS) (Group B) and tubal block (Group C) were included. Long protocol downregulation using recombinant follicular stimulating hormone was used for ovarian stimulation. Aspirated follicular fluid containing mature oocytes were analyzed for ROS levels and the oocytes were assessed for the presence of meiotic spindle using Cri-Oosight™ Polscope. Fertilization, embryo quality, endometrial assessment, and final pregnancy outcome were assessed.

RESULTS:

Meiotic spindles were visualized in a higher proportion of mature oocytes retrieved from women with endometriosis (66%) as compared to those with PCOS (50.5%) and tubal block (62.3%). ROS levels were also observed to be significantly less in the follicular fluid of oocytes in women with endometriosis (Group A) as compared to the other two groups (P ≤ 0.001). However, pregnancy rates were observed to be lower in Group A (32%) than Groups B (39%) and C (44%), respectively. Within each group, oocytes with spindle visualization yielded a higher number of Grade 1 embryos (P < 0.05) as well as lower ROS levels in follicular fluid (P ≤ 0.001) as compared to those where spindle could not be visualized.

CONCLUSIONS:

There was good correlation between spindle imaging and ROS levels as reliable predictors of oocyte assessment. Women with endometriosis had low ROS levels and good spindle imaging results suggesting a possible role of endometrial receptivity accounting for lower pregnancy rates in these women. Poor oocyte quality, as reflected by higher mean ROS levels and low number of oocytes with spindle visualization, could be the factor impeding pregnancy in women with PCOS as compared to women with tubal block.

Regulation of oocyte mitochondrial DNA copy number by follicular fluid, EGF, and neuregulin 1 during in vitro maturation affects embryo development in pigs

Little is known about mitochondrial DNA (mtDNA) replication during oocyte maturation and its regulation by extracellular factors. The present study determined the effects of supplementation of maturation medium with porcine follicular fluid (pFF; 0, 10%, 20%, and 30%) on mtDNA copy number and oocyte maturation in experiment 1; the effects on epidermal growth factor (EGF; 10 ng/mL), neuregulin 1 (NRG1; 20 ng/mL), and NRG1 + insulin-like growth factor 1 (IGF1; 100 ng/mL + NRG1 20 ng/mL), on mtDNA copy number, oocyte maturation, and embryo development after parthenogenic activation in experiment 2; and effects on embryo development after in vitro fertilization in experiment 3. Overall, mtDNA copy number increased from germinal vesicle (GV) to metaphase II (MII) stage oocytes after in vitro maturation (GV: 167 634.6 ± 20 740.4 vs. MII: 275 131.9 ± 9 758.4 in experiment 1; P < 0.05; GV: 185 004.7 ± 20 089.3 vs. MII: 239 392.8 ± 10 345.3 in experiment 2; P < 0.05; Least Squares Means ± SEM). Supplementation of IVM medium with pFF inhibited mtDNA replication (266 789.9 ± 11 790.4 vs. 318 510.1 ± 20 377.4; P < 0.05) and oocyte meiotic maturation (67.3 ± 0.7% vs. 73.2 ± 1.2%, for the pFF supplemented and zero pFF control, respectively; P < 0.01). Compared with the control, addition of growth factors enhanced oocyte maturation. Furthermore, supplementation of NRG1 stimulated mitochondrial replication, increased mtDNA copies in MII oocytes than in GV oocytes, and increased percentage of blastocysts in both parthenogenetic and in vitro fertilized embryos. In this study, mitochondrial biogenesis in oocytes was stimulated during in vitro maturation. Oocyte mtDNA copy number was associated with developmental competence. Supplementation of maturation medium with NRG1 increased mtDNA copy number, and thus provides a means to improve oocyte quality and developmental competence in pigs.

Oocyte quality reflected by follicular fluid analysis in poly cystic ovary syndrome (PCOS): a hypothesis based on intermediates of energy metabolism

There is no clear acceptance of specific follicular fluid biomarker and its correlation with oocyte quality or related embryo variable till now. Most of the studies analyze correlation between certain biomolecules and the oocyte quality using single variable, instead of multivariate analysis algorithms. Our hypothesis is not based on single biomarker discovery, but attempts to explain oocyte quality in terms of energy metabolic pathways by considering its various intermediates. Reduced availability of glucose in the oocytes and follicular cells caused by defective transportation of glucose is expected in polycystic ovary syndrome (PCOS). This initiates alternative pathways to utilize fatty acid, amino acids etc. for energy as a compensatory mechanism to deal with the energy requirement. These compensations can be reflected by altered levels of various biomolecules in follicular fluid (e.g. ketone bodies, lipids, amino acids, lactate, pyruvate etc.). The amount of compensation, in order to meet the energy requirement can be directly correlated to quality of oocytes and better outcome after in vitro fertilization (IVF) in PCOS cases. This can be predicted with fair accuracy by doing a multivariate analysis of altered levels of various biomolecules in follicular fluid. Various supervised and unsupervised classification techniques based on spectroscopic data, obtained from follicular fluid samples may certainly prove to be an important tool to predict oocytes quality and IVF outcome with better accuracy in women with PCOS.

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

OBJECTIVE

The purpose of this study was to evaluate the association between the follicular fluid (FF) reactive oxygen species (ROS) levels, total antioxidant capacity (TAC) and ROS-TAC score and pregnancy after intracytoplasmic sperm injection (ICSI).

METHODS

A total of 138 consecutive women who had ICSI were included in this study. FF ROS and TAC were measured by enhanced chemiluminescence and colorimetric assay, respectively, and then the ROS-TAC score was calculated.

RESULTS

Out of the 138 included patients, 42 (30%) achieved pregnancy after ICSI. Log ROS, TAC, and the ROS-TAC score were not significantly different across diagnoses. Pregnant cycles were associated with significantly lower ROS (P < 0.001), higher TAC (P < 0.001) and higher ROS-TAC scores (P < 0.001). After adjusting for age, there was a significant positive correlation between log ROS and the number of follicles on the day of HCG administration (correlation 0.20, 95% CI: 0.02, 0.39) as well as the number of oocytes retrieved (correlation 0.18, 0.001, 0.36) but not with TAC. Interestingly, in women with endometriosis, higher TAC levels and higher ROS-TAC scores were associated with a higher likelihood of finding normal oocytes (P = 0.005 and P = 0.002, respectively).

CONCLUSION

Higher FF TAC, higher FF ROS-TAC scores and lower FF ROS levels are associated with pregnancy after ICSI. Oxidative stress parameters may be markers of metabolic activity within the follicle.