Effects of controlled ovarian hyperstimulation on oocyte quality in terms of the incidence of apoptotic granulosa cells

Comparison of embryo quality and pregnancy outcomes for patients with low ovarian reserve in natural cycles and mildly stimulated cycles: a cohort study

BACKGROUND

As women with low ovarian reserve embark on the challenging journey of in-vitro fertilisation (IVF) treatment, the choice between natural and mildly stimulated cycles becomes a pivotal consideration. It is unclear which of these two regimens is superior for women with low ovarian reserve. Our study aims to assess the impact of natural cycles on embryo quality and pregnancy outcomes in women with low ovarian reserve undergoing IVF treatment compared to mildly stimulated cycles.

METHODS

This retrospective study enrolled consecutive patients with low ovarian reserve who underwent IVF/intracytoplasmic sperm injection (ICSI) at Guangdong Second Provincial General Hospital between January 2017 and April 2021. The primary outcome for pregnancy rate of 478 natural cycles and 448 mild stimulated cycles was compared. Secondary outcomes included embryo quality and oocyte retrieval time of natural cycles.

RESULTS

The pregnancy rate in the natural cycle group was significantly higher than that in the mildly stimulated cycle group (51.8% vs. 40.1%, p = 0.046). Moreover, natural cycles exhibited higher rates of available embryos (84.1% vs. 78.6%, p = 0.040), high-quality embryos (61.8% vs. 53.2%, p = 0.008), and utilisation of oocytes (73% vs. 65%, p = 0.001) compared to mildly stimulated cycles. Oocyte retrievals in natural cycles were predominantly performed between 7:00 and 19:00, with 94.9% occurring during this time frame. In natural cycles with high-quality embryos, 96.4% of oocyte retrievals were also conducted between 7:00 and 19:00.

CONCLUSION

Natural cycles with appropriately timed oocyte retrieval may present a valuable option for patients with low ovarian reserve.

Granulosa Cells-Related MicroRNAs in Ovarian Diseases: Mechanism, Facts and Perspectives

MicroRNAs (miRNAs) are a class of short single-stranded, noncoding RNAs that affect the translation of mRNAs by imperfectly binding to homologous 3'UTRs. Research on miRNAs in ovarian diseases is constantly expanding because miRNAs are powerful regulators of gene expression and cellular processes and are promising biomarkers. miRNA mimics, miRNA inhibitors and molecules targeting miRNAs (antimiRs) have shown promise as novel therapeutic agents in preclinical development. Granulosa cells (GCs) are supporting cells for developing oocytes in the ovary. GCs regulate female reproductive health by producing sex hormones and LH receptors. Increasing research has reported the relevance of miRNAs in GC pathophysiology. With in-depth studies of disease mechanisms, there are an increasing number of studies on the biomolecular pathways of miRNAs in gynecology and endocrinology. In the present review, we summarize the different functions of GC-related microRNAs in various ovarian disorders, such as polycystic ovary syndrome, premature ovarian insufficiency, premature ovarian failure and ovarian granulosa cell tumors.

Expression of pro-apoptotic and anti-apoptotic proteins in granulosa cells of women with diminished ovarian reserve

PURPOSE

To evaluate the expressions of caspase-3 and cytochrome c and heat shock protein 70 (Hsp70) in granulosa cells (GCs) from women with normal ovarian reserve (NOR) and diminished ovarian reserve (DOR) undergoing intracytoplasmic sperm injection (ICSI).

METHODS

GCs were collected from 117 infertile women during oocyte retrieval. Patients were classified into four groups as follows: DOR-COC score of 0, DOR-COC score of I, NOR-COC score of 0, and NOR-COC score of I. The caspase-3, cytochrome c, and Hsp70 analyses were performed immunohistochemically in GCs. The ICSI outcomes were evaluated prospectively.

RESULTS

The clinical pregnancy and live birth rates were higher in DOR-COC score of I (15, 30.6%; 14, 38.9%) and NOR-COC score of I (19, 38.77%; 19, 52.7%) groups, compared with DOR-COC score of 0 (12, 24.4%; 3, 6.1%) and NOR-COC score of 0 (3, 6.1%; 0%) groups (p = 0.0001; 0.00002), respectively. Caspase-3 and cytochrome c expression levels were higher in DOR-COC score of 0 (23, 65.7%; 25, 71.4%) and NOR-COC score of 0 groups (19, 61.3%; 20, 64.5%), compared with DOR-COC score of I (8, 32%; 9, 36%) and NOR-COC score of I groups (7, 26.9%; 8, 30.8%) (p = 0.00297; p = 0.002), respectively. Lower expression levels of Hsp70 were found in DOR-COC score of 0 (11, 31.4%) and NOR-COC score of 0 groups (10, 32.3%), compared with DOR-COC score of I (16, 64%) and NOR-COC score of I groups (20, 76.9%) (p = 0.001), respectively. Hsp70 expression levels were positively correlated with the number of day 3 good-quality embryo and negatively correlated with estradiol levels in the DOR group.

CONCLUSION

Our data suggest that COC score of 0 is associated with increased expression levels of apoptotic proteins, decreased expression levels of anti-apoptotic protein, and poor ICSI clinical outcomes in women with and without DOR.

Granulosa cells apoptosis and follicular fluid hormones: comparison of progestin-primed ovarian stimulation versus GnRH antagonist protocols

OBJECTIVE

To explore the effect of progestin-primed ovarian stimulation protocol (PPOS) on mural granulosa cells (GCs) apoptosis and hormonal profiles in follicular fluid (FF) and efficacy over GnRH antagonist (GnRH-A) protocols.

METHODS

We performed a prospective cohort study from June through August 2017 at a tertiary teaching hospital. 63 Patients meeting our criteria were recruited in this prospective study voluntarily and stratified to PPOS or GnRH-A group randomly. Mural GCs and FF were collected during oocyte retrieval. Apoptosis of GCs was assessed using the Annexin V-affinity assay by flow cytometry and hormonal profiles in FF were measured using electrochemiluminescence.

RESULTS

A total of 63 women were assessed for eligibility, with 25 cases in PPOS group and 38 in GnRH-A group. Difference of early stage apoptosis rate, late stage apoptosis rate, and total apoptosis rate did not reach statistical significance between groups. Meanwhile, concentrations of hormones in FF were comparable in two groups. No statistically significant differences were observed in number of oocytes retrieved, mature oocyte rate, fertilization rate, and top-quality embryos rate. No patients experienced premature LH surge in both groups during the study.

CONCLUSION

Compared to GnRH antagonist protocol, PPOS had comparable laboratory outcomes, GCs apoptosis rate and hormonal profiles in FF. PPOS is an effective and safe alternative option to provide controlled ovarian hyperstimulation (COH).

After cyclophosphamide exposure, granulosa cells recover their anti-müllerian hormone-producing ability but not their numbers

Anti‐müllerian hormone (AMH) produced by granulosa cells (GCs), reserves the ovarian follicle pool for future recruitment and ovulation. However, women who have undergone cyclophosphamide (Cy) treatment have decreased AMH levels due to damaged GCs. This study establishes flow cytometry protocols for identification of GCs and investigates the cause of the Cy‐induced AMH decrease by analyzing the number of GCs and their AMH production at the single cell level. Over 2 weeks, C57BL/6 mice were intraperitoneally injected 6 times with 100 mg/kg Cy and sacrificed either immediately or 4 weeks after Cy treatment. Twenty‐four hours post‐Cy exposure, a decrease in serum AMH levels was seen due to a reduction in the number of follicle‐stimulating hormone receptor (FSHR)⁺AMH⁺ GCs and their ability to produce AMH. However, 4 weeks after Cy treatment, serum AMH levels were still decreased due to the decreased number of FSHR⁺AMH⁺ GCs, however, their AMH‐producing ability was unaltered. Consistently, in vitro, Cy‐induced low AMH production in FSHR⁺AMH⁺ hGL5 cells (immortalized human GCs) was restored 24 h after Cy treatment, although their numbers remained decreased. Thus, the surviving GCs after Cy exposure had intact AMH‐producing ability. In future, an effort to minimize GC death by Cy treatment is required, while maintaining its therapeutic effects.

Looking Inside the World of Granulosa Cells: The Noxious Effects of Cigarette Smoke

The detrimental implications of tobacco smoke on systemic health have been widely established during the past few decades. Nonetheless, increasing evidence has begun to shed more light on the serious impact that smoke exposure could also have on mammal reproductive health in terms of overall ovarian dysfunction and gestation. A variety of these complications seem to be causally related to specific chemical substances contained in cigarette smoke and their possible effects on ovarian tissues and cells, such as granulosa cells. Granulosa cells represent the functional unit of the ovary and are able to establish a bidirectional cross-talk relationship with the oocyte during folliculogenesis, which makes them vital for its correct growth and development. Based on these premises, the current review focuses on the presence of related smoke-induced damages in granulosa cells. Data have been grouped according to the studied tobacco constituents and the molecular pathways involved, in order to synthesize their impact on granulosa cells and fertility. Attention is further brought to the correlation between electronic cigarettes and female reproduction, although there have been no investigations so far regarding e-cigarette-related granulosa cell exposure. We summarize how tobacco constituents are able to cause alterations in the "life" of granulosa cells, ranging from luteal steroidogenesis and follicular loss to granulosa cell apoptosis and activation of the autophagic machinery. Further studies have been conducted to elucidate the relationship between lifestyle and fertility as to reduce the morbidity connected with infertility.

Luteal granulosa cells from natural cycles are more capable of maintaining their viability, steroidogenic activity and LH receptor expression than those of stimulated IVF cycles

STUDY QUESTION

Are there any differences in the molecular characteristics of the luteal granulosa cells (GC) obtained from stimulated versus non-stimulated (natural) IVF cycles that may help explain the defective luteal phase in the former?

SUMMARY ANSWER

Luteal GC of stimulated IVF cycles, particularly those of agonist-triggered antagonist cycles, are less viable ex vivo, express LH receptor and anti-apoptotic genes at lower levels, undergo apoptosis earlier and fail to maintain their estradiol (E2) and progesterone (P4) production in comparison to natural cycle GC.

WHAT IS KNOWN ALREADY

Luteal function is defective in stimulated IVF cycles, which necessitates P4 and/or hCG administration (known as luteal phase support) in order to improve clinical pregnancy rates and prevent miscarriage. The luteal phase becomes shorter and menstruation begins earlier than a natural cycle if a pregnancy cannot be achieved, indicative of early demise of corpus luteum (premature luteolysis). Supra-physiological levels of steroids produced by multiple corpora luteae in the stimulated IVF cycles are believed to inhibit LH release directly via negative feedback actions on the hypothalamic-pituitary-ovarian axis resulting in low circulating levels of LH and a defective luteal phase. We hypothesized that some defects in the viability and steroidogenic activity of the luteal GC of the stimulated IVF cycles might contribute to this defective luteal phase in comparison to natural cycle GC. This issue has not been studied in human before.

STUDY DESIGN, SIZE, DURATION

A comparative translational research study of ex vivo and in vitro models of luteal GC recovered from IVF patients undergoing natural versus stimulated IVF cycles was carried out. Luteinized GC were obtained from 154 IVF patients undergoing either natural (n = 22) or stimulated IVF cycles with recombinant FSH and GnRH agonist (long) (n = 44), or antagonist protocol triggered conventionally either with recombinant hCG (n = 46) or with a GnRH agonist (n = 42). GC were maintained in vitro for up to 6 days.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Cellular viability (YO-PRO-1 staining), the expression of the steroidogenic enzymes, pro-apoptotic genes [Bcl-2-associated death promoter (BAD), Bcl-2-associated X protein (BAX) and Caspase-3 (CASP3)], anti-apoptotic genes [RAC-alpha serine/threonine-protein kinase (AKT-1) and Bcl-2-like protein 2 (BCL2-L2)], LH receptor, vascular endothelial growth factor (VEGF) (using real-time quantitative PCR at mRNA level and western blot immunoprecipitation assay at protein level) and in vitro E2 and P4 production (electrochemiluminescence immunoassay) were compared in GC among the groups.

MAIN RESULTS AND THE ROLE OF CHANCE

Natural cycle GC were significantly more viable ex vivo (88%) compared to their counterparts of the stimulated IVF cycles (66, 64 and 37% for agonist and antagonist cycles triggered with hCG and GnRH agonist respectively, P < 0.01). They were also more capable of maintaining their vitality in culture compared to their counterparts from the stimulated IVF cycles: at the end of the 6-day culture period, 74% of the cells were still viable whereas only 48, 43 and 22% of the cells from the agonist and antagonist cycles triggered with hCG and agonist respectively, were viable (P < 0.01). The mRNA expression of anti-apoptotic genes (AKT-1 and BCL2-L2) was significantly lower, while that of pro-apoptotic genes (BAD, BAX and CASP3) was significantly higher in the stimulated cycles, particularly in the agonist-triggered antagonist cycles, compared to natural cycle GC (P < 0.01 for long protocol and antagonist hCG trigger, P < 0.001 for agonist trigger). The expression of steroidogenic enzymes (stAR, SCC, 3β-HSD and aromatase) and VEGF was significantly higher in the agonist and hCG-triggered antagonist cycles compared to natural cycle GC. Therefore, in vitro E2 and P4 production in cells from the stimulated IVF cycles was significantly higher than their counterparts obtained from the natural cycles in the first 2 days of culture. However, after Day 2, their viability and hormone production began to decline very rapidly with the most drastic decrease being observed in the agonist-triggered cycles. By contrast, natural cycle GC maintained their viability and produced E2 and P4 in increasing amounts in culture up to 6 days. In vitro P production and the mRNA and protein expression of LH receptor, VEGF and 3β-HSD were most defective in the agonist-triggered antagonist cycles compared to natural and agonist and hCG-triggered antagonist cycles. In vitro hCG treatment of a subset of the cells from the agonist-triggered cycles improved their viability, increased E2 and P4 production in vitro and up-regulated the mRNA expression of anti-apoptotic gene BCL-L2 together with steroidogenic enzymes stAR, SCC, 3B-HSD, LH receptor and VEGF.

LARGE SCALE DATA

Not applicable.

LIMITATIONS, REASONS FOR CAUTION

The limitations include analysis of luteinized GC only might not reflect the in vivo mechanisms involved in survival and function of the whole corpus luteum; GC recovered during oocyte retrieval belong to a very early stage of the luteal phase and might not be representative; effects of ovulation triggered with hCG may not equate to the endogenous LH trigger; the clinical characteristics of the patients may vary among the different groups and it was not possible to correlate stimulation-related molecular alterations in luteal GC with the clinical outcome, as no oocytes have been utilized yet. Therefore, our findings do not conclusively rule out the possibility that some other mechanisms in vivo may also account for defective luteal function observed in stimulated IVF cycles.

WIDER IMPLICATIONS OF THE FINDINGS

Ovarian stimulation is associated with significant alterations in the viability and steroidogenic activity of luteal GC depending on the stimulation protocol and mode of ovulation trigger. Reduced survival and down-regulated expression of 3B-HSD, LH receptor and VEGF leading to compromised steroid production in stimulated cycles, and particularly in the agonist-triggered cycles, may at least in part help explain why the luteal phase is defective and requires exogenous support in these cycles.

STUDY FUNDING/COMPETING INTEREST(S)

This study was funded by the School of Medicine, the Graduate School of Health Sciences of Koc University and Koç University Research Center for Translational Medicine (KUTTAM), equally funded by the Republic of Turkey Ministry of Development Research Infrastructure Support Program. All authors declare no conflict of interest.

Electroacupuncture Enhances Number of Mature Oocytes and Fertility Rates for In Vitro Fertilization

Objective: The increasing prevalence of infertility every year is in line with the increasing need for in vitro fertilization (IVF) programs. Failure of oocyte maturation is an obstacle that often causes low success in IVF. According to several studies, controlled ovarian stimulation (COS) has been reported to increase the risk of granulosa-cell apoptosis associated with inhibition of oocyte maturation. This study was conducted to determine the effect of electroacupuncture (EA) on oocyte maturation; rate of fertilization; granulosa-cell apoptosis; and levels of growth-differentiation factor 9 (GDF9) and bone-morphogenetic protein 15 (BMP15) an IVF program. Materials and Methods: A randomized controlled trial was conducted with 24 subjects who were in the IVF program. Subjects were randomly allocated into verum-EA (n = 12) and sham-EA groups (n = 12). Microscopic assessment of oocyte maturation and rate of fertilization was performed by embryologists, and examinations of granulosa-cell apoptosis index (Bax/Bcl-2 ratio), GDF9, and BMP15 were performed, using real-time quantitative polymerase chain reaction and messenger-RNA techniques. Results: There were significant differences in oocyte maturation (P = 0.02) and fertilization rates (P = 0.03) between the verum-EA and sham-EA groups. There were differences in granulosa-cell apoptosis index between the verum-EA and sham-EA groups (P < 0.001). There were significant differences in Bax-protein expression (P = 0.04) and Bcl-2 (P = 0.03) granulosa cells between the verum-EA and sham-EA groups. There was no significant difference in GDF9 levels (P = 0.34) and BMP15 (p = 0.47) between the verum-EA and sham-EA groups. Conclusions: EA can enhance oocyte maturation and fertilization rate, and reduce the granulosa-cell apoptosis index in an IVF program.

Apoptosis of mural granulosa cells is increased in women with diminished ovarian reserve

Purpose

To evaluate the relationship between apoptosis of granulosa cells in women with normal ovarian reserve versus diminished ovarian reserve, and relate that to follicular fluid hormones, and to clinical outcomes.

Methods

A prospective cohort study was initiated between October 2015 and June 2016 involving a total of 164 women undergoing IVF/ICSI cycles at a single IVF center. Mural and cumulus granulosa cells, and follicularfluid were collected during oocyte retrieval. Annexin V-FITC/PI apoptosis staining and flow cytometryanalysis were performed to evaluate apoptosis rate of mural granulosa cells and cumulus cells. Follicularfluid hormones were measured by ECLIA. Laboratory and clinical outcomes were analyzed.

Results

In mural granulosa cells, early, late and total apoptosis rates were significantly increased in women with diminished ovarian reserve when compare to women with normal ovarian reserve, along with lower AMHand progesterone levels (but higher estradiol levels) in follicular fluid. Early apoptosis rate of cumulus cellswas significantly higher in the non-pregnant group. The apoptosis rate of mural cells was negativelycorrelated with parameters related to ovarian response, oocyte yield, MII egg number, 2pn cleavagenumber, D3 good embryos number, blastocyst formation rate and frozen embryos number. A positivecorrelation was found between mural granulosa cell apoptosis and age.

Conclusion

A significantly higher apoptosis rate of mural granulosa cells was correlated with worse ovarian response, with fewer egg and embryo numbers in IVF/ICSI, as well as with age. Early apoptosis rate of cumulus cellsmight also have influence on clinical pregnancy.

Electronic supplementary material

The online version of this article (10.1007/s10815-019-01446-5) contains supplementary material, which is available to authorized users.

Granulosa Cell Apoptosis in the Ovarian Follicle-A Changing View

Recent studies challenge the previous view that apoptosis within the granulosa cells of the maturing ovarian follicle is a reflection of aging and consequently a marker for poor quality of the contained oocyte. On the contrary, apoptosis within the granulosa cells is an integral part of normal development and has limited predictive capability regarding oocyte quality or the ensuing pregnancy rate in in vitro fertilization programs. This review article covers our revised understanding of the process of apoptosis within the ovarian follicle, its three phenotypes, the major signaling pathways underlying apoptosis as well as the associated mitochondrial pathways.

Apoptotic biomarkers in cumulus cells in relation to embryo quality in polycystic ovary syndrome

PURPOSE

To investigate associations between gene expression pattern of apoptotic biomarkers in cumulus cells of polycystic ovary syndrome (PCOS) patients and the quality of oocytes and embryos.

METHODS

40 intracytoplasmic sperm injection patients, of whom 20 were PCOS and 20 were healthy women, were included in this study. Serum hormone levels were measured using Radioimmunoassay for each patient. The expression of survivin, caspase-3, and caspase-7 in 200 cumulus complexes surrounding mature oocytes (100 in PCOS versus 100 in control groups) collected individually at pick up was examined by real-time polymerase chain reaction (real-time PCR).

RESULTS

The expression levels of survivin were significantly lower in PCOS patients than those of normal women while caspase-3 and caspase-7 expression levels were higher in PCOS patients (p < 0.05). There was a statistically significant correlation between the levels of these genes and embryo quality.

CONCLUSIONS

This study reveals that the measurement of survivin, caspase-3, caspase-7 levels in cumulus cells of PCOS patients could be used as genetic biomarkers for oocyte and embryo selection under an ART program. However, further prospective studies are required to elucidate this issue.

Altered FoxO3 expression and apoptosis in granulosa cells of women with polycystic ovary syndrome

PURPOSE

To determine the level of apoptosis, and alteration of FoxO3 (forkhead box O3 transcription factor) expression and phosphorylation in human granulosa cells amongst polycystic ovary syndrome (PCOS) patients and control group.

METHODS

We recruited infertile women with PCOS (n = 14) and compared them with infertile women due to tubal blockage or male factor infertility (n = 14, controls). GnRH agonist and gonadotropins were used for ovarian stimulation. Follicular fluids from large follicles (>16 mm) were pooled and granulosa cells (GCs) were isolated using cell strainer methodology. Apoptosis of purified GCs was measured by flow cytometry using Annexin V and propidium iodide. Quantitative real-time PCR and western blotting were performed to assess alteration of FoxO3 expression and phosphorylation in GCs.

RESULTS

There were higher percentages of early and late apoptosis in GCs of PCOS patients than in the control group. FoxO3 mRNA level and total FoxO3 protein were significantly higher in PCOS group than in the control group. The ratio of p-FoxO3/total FoxO3 decreased significantly in PCOS than in the control group. It was inferred that unphosphorylated (active form) FoxO3 was higher in GCs of PCOS patients. Apoptosis was significantly and positively correlated with the total FoxO3 and negatively correlated with the p-FoxO3 protein levels in PCOS patients.

CONCLUSIONS

Activation and overexpression of FoxO3 in granulosa cells of PCOS women correlated with higher apoptosis levels in these cells suggesting that FoxO3 may be a candidate for the higher apoptosis in granulosa cells from women with PCOS.

Expression profiles of select genes in cumulus–oocyte complexes from young and aged mares

There is compelling evidence that oocytes from mares >18 years of age have a high incidence of inherent defects that result in early embryonic loss. In women, an age-related decrease in oocyte quality is associated with an increased incidence of aneuploidy and it has recently been determined that the gene expression profile of human oocytes is altered with advancing age. We hypothesised that similar age-related aberrations in gene expression occur in equine oocytes. Therefore, the aim of the present study was to compare gene expression profiles of individual oocytes and cumulus cells from young and aged mares, specifically evaluating genes that have been identified as being differentially expressed with advancing maternal age and/or aneuploidy in human oocytes. Expression of 48 genes was compared between 14 cumulus–oocyte complexes (COCs) from mares aged 3–12 years and 10 COCs from mares ≥18 years of age. Three genes (mitochondrial translational initiation factor 3 (IF3), heat shock transcription factor 5 (HSF5) and Y box binding protein 2 (YBX2)) were differentially expressed in oocytes, with all being more abundant in oocytes from young mares. Three genes (ADP-ribosylation factor-like 6 interacting protein 6 (ARL6IP6), BCL2-associated X protein (BAX) and hypoxia upregulated 1 (HYOU1)) were differentially expressed in cumulus cells, with all being more abundant in aged mares. The results of the present study confirm there are age-related differences in gene expression in equine COCs, which may be associated with the lower quality and decreased developmental competence of oocytes from aged mares.

An increase of granulosa cell apoptosis mediates aqueous neem (Azadirachta indica) leaf extract-induced oocyte apoptosis in rat

Objective:

Neem plant (Azadirachta indica) has been extensively used in Ayurvedic system of medicine for female fertility regulation for a long time, but its mechanism of action remains poorly understood. Hence, the present study was aimed to determine whether an increase of granulosa cell apoptosis is associated with aqueous neem leaf extract (NLE)-induced oocyte apoptosis.

Materials and Methods:

Sexually immature female rats of 20 days old were fed NLE (50 mg/day) for 10 days and then subjected to superovulation induction protocol. The morphological changes in cumulus oocyte complexes (COCs), rate of oocyte apoptosis, hydrogen peroxide (H₂O₂), total nitrite, and cytochrome c concentrations, inducible nitric oxide synthase (iNOS), cytochrome c, p53, Bcl2 and Bax expressions, deoxyribonucleic acid (DNA) fragmentation, and estradiol 17β level in granulosa cells collected from preovulatory COCs were analyzed.

Results:

Aqueous NLE increased H₂O₂ concentration and decreased catalase activity, increased iNOS expression and total nitrite concentration, increased p53, Bax, and p53 expressions but decreased Bcl2 expression, increased cytochrome c concentration and induced DNA fragmentation in granulosa cells. An increased granulosa cell apoptosis resulted in reduced estradiol 17β concentration and induced apoptosis in ovulated oocytes.

Conclusion:

We conclude that aqueous NLE-induced granulosa cell apoptosis through the mitochondria-mediated pathway, reduced estradiol 17β concentration and induced apoptosis in ovulated oocytes. Thus, granulosa cell apoptosis mediates NLE-induced oocyte apoptosis during female fertility regulation in rat.

Expression of antiapoptosis gene survivin in luteinized ovarian granulosa cells of women undergoing IVF or ICSI and embryo transfer: clinical correlations

BACKGROUND

The purpose of the study was to determine the incidence of survivin gene expression in human granulosa cells during ovarian stimulation in Greek women with normal FSH levels, undergoing IVF or ICSI and to discover any correlation between levels of gene expression and clinical parameters, efficacy of ovulation or outcomes of assisted reproduction.

METHODS

Twenty nine women underwent ovulation induction for IVF or ICSI and ET with standard GnRH analogue-recombinant FSH protocol. Infertility causes were male and tubal factor. Cumulus-mature oocyte complexes were denuded and the granulosa cells were analyzed for each patient separately using quantitative reverse transcription polymerase chain reaction analysis for survivin gene expression with internal standard the ABL gene.

RESULTS

The ABL and survivin mRNA were detected in granulosa cells in 93.1%. The expression levels of survivin were significantly lower in normal women (male infertility factor) compared to women with tubal infertility factor (p = 0.007). There was no additional statistically significant correlation between levels of survivin expression and estradiol levels or dosage of FSH for ovulation induction or number of dominant follicles aspirated or number of retrieved oocytes or embryo grade or clinical pregnancy rates respectively.

CONCLUSIONS

High levels of survivin mRNA expression in luteinized granulosa cells in cases with tubal infertility seem to protect ovaries from follicular apoptosis. A subpopulation of patients with low levels of survivin mRNA in granulosa cells might benefit with ICSI treatment to bypass possible natural barriers of sperm-oocyte interactions.

Hyaluronan is required for cranial neural crest cells migration and craniofacial development

BACKGROUND

Hyaluronan is a crucial glycosaminoglycan of the vertebrate embryonic extracellular matrix able to influence cell behaviour, both by assembling the pericellular matrices and by activating signal transducing receptors such as CD44.

RESULTS

We showed that the hyaluronan synthases, Has1 and Has2, and CD44 display a dynamic expression pattern during cranial neural crest cells (NCC) development. By knocking down Has1 and Has2 gene functions, we revealed that hyaluronan synthesized by Has1 and Has2 is necessary for the proper development of the visceral skeleton.

CONCLUSIONS

The data suggest that hyaluronan helps to maintain the active migratory behaviour of cranial NCC, and that its presence around pre-chondrogenic NCC is crucial for their survival. CD44 knock down also suggests that the role of hyaluronan in cranial NCC migration could be mediated, at least in part, by the activation of CD44. These findings contribute to the unveiling of the functional relation between NCC and their extracellular environment during craniofacial development.

[Follicular atresia: Its features as predictive markers for the outcome of assisted reproduction]

The mammalian ovary is an extremely dynamic organ in which excessive or defective follicles are rapidly and effectively eliminated continuously throughout reproductive life. More than 99 % of follicles disappear, due to apoptosis of granulosa cells, and only one or few of the surviving follicles successfully complete the path to ovulation. The balance between signals for cell death and survival determines the destiny of the follicles. In this review, we provide a short overview of the role of programmed cell death essentially in adult folliculogenesis. We highlight molecules involved in regulation of granulosa cell apoptosis. We further discuss the potential use of scores for apoptosis in granulosa cells and characteristics of follicular fluid as prognostic markers for predicting the outcome of assisted reproduction.

Mitochondrial dysfunction and apoptosis in cumulus cells of type I diabetic mice

Impaired oocyte quality has been demonstrated in diabetic mice; however, the potential pathways by which maternal diabetes exerts its effects on the oocyte are poorly understood. Cumulus cells are in direct contact with the oocyte via gap junctions and provide essential nutrients to support oocyte development. In this study, we investigated the effects of maternal diabetes on the mitochondrial status in cumulus cells. We found an increased frequency of fragmented mitochondria, a decreased transmembrane potential and an aggregated distribution of mitochondria in cumulus cells from diabetic mice. Furthermore, while mitochondrial biogenesis in cumulus cells was induced by maternal diabetes, their metabolic function was disrupted as evidenced by lower ATP and citrate levels. Moreover, we present evidence suggesting that the mitochondrial impairments induced by maternal diabetes, at least in part, lead to cumulus cell apoptosis through the release of cytochrome c. Together the deleterious effects on cumulus cells may disrupt trophic and signaling interactions with the oocyte, contributing to oocyte incompetence and thus poor pregnancy outcomes in diabetic females.

N-acetyl cysteine: could it be an effective adjuvant therapy in ICSI cycles? A preliminary study

This randomized controlled trial tested the hypothesis that addition of N-acetyl cysteine (NAC) can increase the probability of pregnancy in intracytoplasmic sperm injection (ICSI) cycles using the long agonist protocol. Women undergoing ICSI cycles due to male factor were randomly assigned to receive either long protocol (group A, 38 women) or long protocol plus NAC (group B, 38 women). Clinical pregnancy was the primary outcome. Granulosa cell apoptosis, fertilization rate, number of grade-one embryos and ongoing pregnancy were the secondary outcomes. Clinical pregnancy rate was insignificantly higher in NAC group (52.6%) than control (47.4%). Early and late apoptosis were also insignificantly lower in group B than in group A. Irrespective of the used protocol, there was significant negative correlation between both early and late apoptosis and fertilization rate (both P<0.001) and the number of good-quality embryos (P=0.007 and P<0.001, respectively). Pregnant patients had significantly lower early and late apoptosis than those who didn't achieve pregnancy (P<0.001). In conclusion, NAC supplementation did not significantly increase the probability of pregnancy in ICSI cycles using long agonist protocol. It appears that granulosa cell apoptosis may be an important prognosticator for ICSI cycle outcome.

Effect of GnRH down-regulation on cumulus cell viability and apoptosis as measured by fluorescence-activated cell sorting

OBJECTIVE

To determine whether gonadotropin releasing hormone (GnRH)-agonist or -antagonist induces higher percentages of cumulus cell apoptosis and if the use of either is detrimental to ART outcomes.

PATIENTS

Women in a private facility under treatment for IVF had their cumulus cells isolated and analyzed by flow cytometry. Viable, apoptotic, and dead cumulus cell rates related to ovarian stimulation by GnRH-agonist or -antagonist were measured and compared with fertilization and implantation rates.

RESULTS

Treatment with GnRH-agonist produced a greater number of follicles than treatment with GnRH-antagonist. No differences in implantation and pregnancy rates were found. While cumulus cell (CC) apoptosis was positively correlated with estradiol on the day of hCG administration, no significant difference in the percentage of apoptotic cells between treatments was detectable. Additionally, implantation rate and the average follicular estradiol production on the day of hCG administration were no different between treatments.

CONCLUSIONS

GnRH-agonist or -antagonist treatment protocols induce similar levels of apoptosis in CCs and are not detrimental to ART outcomes.

Effect of apoptosis and reactive oxygen species production in human granulosa cells on oocyte fertilization and blastocyst development

PURPOSE

The aim was to establish the impact of human granulosa cell apoptosis and reactive oxygen species (ROS) production on fertilization competence of the oocyte, embryo developmental stage and implantation rate.

METHODS

Thirty women undergoing IVF-ET for tubal factor infertility were included; GnRH antagonists and gonadotrophins were used for ovarian stimulation. Granulosa cells were isolated from each aspirated follicle using gradient centrifugation. Apoptosis was studied by flow cytometry using annexin V and propidium iodide. ROS production was studied with hydroethidine staining and analyzed by flow cytometry.

RESULTS

There were no differences in characteristics of granulosa cells between the follicles with fertilized and non-fertilized oocytes. The analyzed characteristics of granulosa cells in corresponding follicles had no effect on embryo developmental stage on day 5. The percentage of ROS producing granulosa cells was lower in the follicles giving rise to blastocysts that resulted in implantation compared to those that did not (39.9% versus 69.9%, P = 0.031).

CONCLUSIONS

Apoptosis and ROS production in granulosa cells have no significant impact on fertilization and do not correlate with the development of blastocysts. An increased percentage of ROS producing granulosa cells results in fewer oocytes retrieved and diminishes implantation rate.

The Chemokine SDF-1/CXCL12 Contributes to T Lymphocyte Recruitment in Human Pre-ovulatory Follicles and Coordinates with Lymphocytes to Increase Granulosa Cell Survival and Embryo Quality

We investigated the production and the role of the chemokine stromal cell-derived factor-1 (SDF-1/CXCL12) in pre-ovulatory follicles of women undergoing in vitro fertilization. We detected CXCL12 and its receptor CXCR4 by flow cytometry, western blotting and RT-PCR. We tested cell migration in Transwell experiments. We measured apoptosis using delta psi m-sensitive fluorescent probe DiOC6(3) and we screened apoptosis-related gene expression with macro-arrays. Granulosa cells from follicular aspirates produce CXCL12 that contributes to T lymphocytes recruitment. CXCL12 reduces early apoptosis of granulosa cells. This effect is accompanied by a shift of bcl2/bax ratio, and decreased expression of p53-targeted genes (pig7, pig8, p21, gadd45). Removal of lymphocytes disables CXCL12-mediated anti-apoptotic effect on granulosa cells. Anti-apoptotic activity of CXCL12 is positively correlated to high quality of embryos. In conclusion, CXCL12 is locally produced by luteinizing granulosa cells. It specifically contributes to T lymphocytes recruitment and coordinates with local lymphocytes to increase granulosa cell survival and embryo quality.

Predictive value of cumulus cell apoptosis with regard to blastocyst development of corresponding gametes

OBJECTIVE

To test if a high degree of apoptosis in cumulus cells could indicate diminished oocyte quality and developmental competence.

DESIGN

Prospective analysis.

SETTING

Public hospital and university.

PATIENT(S)

Thirty seven women who gave written consent to participate in this study.

INTERVENTION(S)

Cumulus-oocyte complexes were denuded separately and the resulting cumulus cell suspensions were analyzed for presence of apoptosis using a terminal deoxynucleotidyl transferase-mediated digoxigenin-dUTP nick-end labeling (TUNEL) assay detection kit.

MAIN OUTCOME MEASURE(S)

Percentage of apoptotic cumulus cells and blastocyst formation rate.

RESULT(S)

Younger patients (< or = 35 years) showed significantly fewer apoptotic cumulus cells than older ones. In all patients gamete maturity was shown to be highly correlated to the rate of apoptosis in cumulus cells. At zygote and cleavage stages (days 1 to 4) no morphologic features were related to the degree of programmed cell death. However, blastocyst development was predictable taking into account the percentage of apoptosis in associated somatic cells. In addition, there was a trend toward better quality blastocysts from follicles with a lower rate of apoptotic cells. No influence on pregnancy and implantation rate was observed.

CONCLUSION(S)

Apoptotic processes within follicles seem to impair oocyte maturation. Though not manifested in the morphologic appearance, gametes and embryos derived from cumulus complexes with no or minor apoptosis have an increased chance of giving rise to optimal blastocysts.

Significance of mRNA levels of connexin37, connexin43, and connexin45 in luteinized granulosa cells of controlled hyperstimulated follicles

OBJECTIVE

To evaluate the mRNA levels of connexins in different sizes of luteinized follicles.

DESIGN

Semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) to determine the connexin mRNA levels in the granulosa cells of 91 luteinized follicles.

SETTING

Academic tertiary care medical center and research unit of university.

PATIENT(S)

Ninety-one female patients on controlled ovarian hyperstimulation (COH).

INTERVENTION(S)

Sonoguided aspiration to collect the oocytes and the granulosa cells simultaneously.

MAIN OUTCOME MEASURE(S)

The RT-PCR data are normalized by comparing the intensity of the connexins to the intensity of internal controls (beta-actin). The follicles are grouped according to the size and the mRNA levels of the connexins. The correlations among the size of the follicles, the outcome of oocytes, and the mRNA levels of the connexins are compared by Fisher's exact test and Mann-Whitney test.

RESULT(S)

The mRNA levels of the connexins are low in the follicles equal or larger than 5.5 mL. High cx43 levels are linked to good prognosis of oocytes.

CONCLUSION(S)

The luteinized granulosa cells from the large follicles are relatively quiescent in the connexin mRNA expression. In addition to the volume, the mRNA levels of cx43 may serve as a marker to predict the outcome of oocytes.

Effects of a Gonadotropin-Releasing Hormone agonist and Follicle Stimulating Hormone on the incidence of apoptosis in human luteinized granulosa cells

OBJECTIVE

Previous studies have shown the importance of apoptosis in follicular atresia occurring especially in granulosa cells (GC) and its relation to the outcome of in vitro fertilization (IVF). The aim of this study was to evaluate the effects of a Gonadotropin-Releasing Hormone agonist (GnRHa) and of Follicle-Stimulating Hormone (FSH) on the apoptosis rate of human luteinized GC.

STUDY DESIGN

GC were isolated from follicular fluids of 15 women undergoing IVF cycles, cultured for 1 day and then treated for 1 day in serum-free medium with triptorelin at 100 or 1000pg/ml or with FSH at 100 or 500ng/ml. GC cultured without any hormone addition were used as controls. Treatment of cultured GC with triptorelin 100pg/ml and FSH 100ng/ml was performed five times each. GC were analysed by flow cytometry after propidium iodide staining to measure the percentage of apoptotic GC. Some triptorelin-treated GC were also examined by electron microscopy.

RESULTS

Percentages of GC apoptosis were after hormone treatment respectively: FSH: 100ng/ml, 2.9+/-0.6%; 500ng/ml, 2.9%; triptorelin: 100pg/ml, 18.6+/-2.8%; 1000pg/ml, 86.5% versus 9.8+/-1.8% in GC controls (FSH 100ng/ml versus control; triptorelin 100pg/ml versus control: P<10(-6)). Electron microscopy confirmed apoptosis of GC incubated with triptorelin.

CONCLUSIONS

This study demonstrated that FSH decreased apoptosis in human luteinized GC. In contrast, triptorelin was possibly implicated in a dose-dependent increase in the incidence of apoptotic GC. This last result suggests that clinical use of GnRHa should perhaps be reconsidered in the context of its apoptosis-inducing effect.