Messenger RNA expression for the follicle-stimulating hormone receptor and luteinizing hormone receptor in human oocytes and preimplantation-stage embryos

The effects of flexible short protocol with gonadotropin-releasing hormone antagonist on preventing premature ovulation in poor responders

PURPOSE

The proportion of patients with poor ovarian response (POR) is increasing, but effective treatment remains a challenge. To control the hidden peaks of luteinizing hormone (LH) and premature ovulation for poor responders, this study investigated the efficacy of flexible short protocol (FSP) with gonadotropin-releasing hormone antagonist (GnRH-ant) on trigger day.

METHODS

The 662 cycles of POR patients were retrospectively analyzed. The cohort was divided into control and intervention groups. The intervention group (group A) with 169 cycles received a GnRH-ant given on trigger day. The control (group B) with 493 cycles received only FSP. The clinical outcomes of the two groups were compared.

RESULTS

Compared with group B, with gonadotropin-releasing hormone antagonist (GnRH-ant) on trigger day in group A the incidences of spontaneous premature ovulation decreased significantly (2.37% vs. 8.72%, P < 0.05). The number of fresh embryo-transfer cycles was 45 in group A and 117 in group B. There were no significant differences in clinical outcomes, including implantation rate, clinical pregnancy rate, live birth rate and the cumulative live birth rate (12.0% vs. 9.34%; 22.22% vs. 21.93%; 17.78% vs. 14.91%; 20.51% vs. 20%, respectively; P > 0.05) between the two group.

CONCLUSION

FSP with GnRH-ant addition on trigger day had no effect on clinical outcomes, but could effectively inhibit the hidden peaks of luteinizing hormone (LH) and spontaneous premature ovulation in POR. Therefore, it is an advantageous option for POR women.

Hemodynamic, endocrine, and gene expression mechanisms regulating equine ovarian follicular and cellular development

Ovulatory follicle development and associated oocyte maturation involve complex coordinated molecular and cellular mechanisms not yet fully understood. This study addresses the relationships among follicle diameter, follicle wall blood flow, follicular-fluid factors, and gene expression for follicle growth, steroidogenesis, angiogenesis, and apoptosis in granulosa/cumulus cells and oocytes during different stages from the beginning of largest/ovulatory follicle to impending ovulation in mares. The most remarkable findings were (i) a positive association between follicle development, follicle blood flow, intrafollicular follicle-stimulating hormone (FSH), luteinizing hormone (LH), estradiol, progesterone, and messenger RNA (mRNA) expression for FSHR and LHCGR in granulosa cells of the largest/ovulatory follicle; (ii) a plateau or decrease in follicle diameter and blood flow and granulosa cell mRNA for FSHR, LHCGR, IGF1R, VEGFR2, CYP19A1, and CASP3 at the preovulatory stage; (iii) higher StAR and BCL2 and lower CASP3 mRNA in granulosa cells at the time of impending ovulation; (iv) greater IGF1R mRNA for granulosa cells at the predeviation stage; and (v) lower FSHR, LHCGR, IGF1R, and VEGFR2 mRNA in cumulus cells and greater LHCGR and IGF1R mRNA in oocytes at the ovulatory stage. This study is a critical advance in the understanding of molecular mechanisms of follicle development and oocyte maturation and is expected to be vital for future studies targeting potential markers.

Actions and Roles of FSH in Germinative Cells

Follicle stimulating hormone (FSH) is produced by the pituitary gland in a coordinated hypothalamic-pituitary-gonadal (HPG) axis event, plays important roles in reproduction and germ cell development during different phases of reproductive development (fetal, neonatal, puberty, and adult life), and is consequently essential for fertility. FSH is a heterodimeric glycoprotein hormone of two dissociable subunits, α and β. The FSH β-subunit (FSHβ) function starts upon coupling to its specific receptor: follicle-stimulating hormone receptor (FSHR). FSHRs are localized mainly on the surface of target cells on the testis and ovary (granulosa and Sertoli cells) and have recently been found in testicular stem cells and extra-gonadal tissue. Several reproduction disorders are associated with absent or low FSH secretion, with mutation of the FSH β-subunit or the FSH receptor, and/or its signaling pathways. However, the influence of FSH on germ cells is still poorly understood; some studies have suggested that this hormone also plays a determinant role in the self-renewal of germinative cells and acts to increase undifferentiated spermatogonia proliferation. In addition, in vitro, together with other factors, it assists the process of differentiation of primordial germ cells (PGCLCs) into gametes (oocyte-like and SSCLCs). In this review, we describe relevant research on the influence of FSH on spermatogenesis and folliculogenesis, mainly in the germ cell of humans and other species. The possible roles of FSH in germ cell generation in vitro are also presented.

The role of gonadotropin-releasing hormone agonists in female fertility preservation

Advances in anticancer treatments have resulted in increasing survival rates among cancer patients. Accordingly, the quality of life after treatment, particularly the preservation of fertility, has gradually emerged as an essential consideration. Cryopreservation of embryos or unfertilized oocytes has been considered as the standard method of fertility preservation among young women facing gonadotoxic chemotherapy. Other methods, including ovarian suppression and ovarian tissue cryopreservation, have been considered experimental. Recent large-scale randomized controlled trials have demonstrated that temporary ovarian suppression using gonadotropin-releasing hormone agonists (GnRHa) during chemotherapy is beneficial for preventing chemotherapy-induced premature ovarian insufficiency in breast cancer patients. It should also be emphasized that GnRHa use during chemotherapy does not replace established fertility preservation methods. All young women facing gonadotoxic chemotherapy should be counseled about and offered various options for fertility preservation, including both GnRHa use and cryopreservation of embryos, oocytes, and/or ovarian tissue.

Low Serum LH Levels During Ovarian Stimulation With GnRH Antagonist Protocol Decrease the Live Birth Rate After Fresh Embryo Transfers but Have No Impact in Freeze-All Cycles

OBJECTIVE

To explore the association between serum LH levels and the cumulative live birth rate (CLBR) within one complete cycle, and the impact of serum LH levels on the live birth rate (LBR) after the initial embryo transfer (ET) considering different ET strategies (fresh or freeze-all).

DESIGN

A retrospective cohort study.

SETTING

University-affiliated reproductive center.

PATIENTS

1480 normogonadotrophic women who underwent COS with GnRH antagonist protocol for the first IVF/ICSI attempt.

INTERVENTIONS

The sample was stratified into low and higher LH groups according to serum LH peak levels of <4 (Group A) and ≥4 IU/L (Group B) during COS. Patients were also sub-grouped into conventional fresh/frozen ET cycles and freeze-all cycles.

MAIN OUTCOME MEASURES

The LBR after the initial embryo transfer and the CLBR within one complete cycle.

SECONDARY OUTCOME MEASURES

The numbers of day-3 high-quality embryos, the numbers of embryos available, and the other pregnancy outcomes after the initial ET.

RESULTS

In the whole cohort, the CLBRs decreased significantly in the low (63.1% vs. 68.3%, P=.034) LH group compared to the higher LH group. Subgroup analysis revealed that patients with low LH levels had lower LBR after fresh ET (38.0% vs. 51.5%, P=.005) but comparable LBR after the first frozen-thawed ET (FET) in freeze-all cycles (49.8% vs. 51.8%, P=.517) than patients with higher LH peak levels. Likewise, patients with low LH levels had lower CLBR for conventional fresh/frozen ET cycles (54.8% vs. 66.1%, P=.015) but comparable CLBR for the freeze-all cycles (66.8% vs. 69.2%, P=.414) than those with higher LH levels. Following confounder adjustment, multivariable regression analyses showed that low LH level was an independent risk factor for the CLBR in the whole cohort (odds ratio (OR): 0.756, 95% confidence interval (CI): 0.604-0.965, P=.014) and in patients who underwent the conventional ET strategy (OR: 0.596, 95% CI: 0.408-0.917, P=.017). Moreover, the adverse impact of low LH levels on LBRs maintained statistically significant after fresh transfers (OR: 0.532, 95% CI: 0.353-0.800, P=.002) but not after the first FETs in freeze-all cycles (OR: 0.918, 95% CI: 0.711-1.183, P=.508).

CONCLUSIONS

In comparison with higher LH levels, low LH levels decrease the CLBRs per oocyte retrieval cycle for normogonadotrophic women who underwent COS using GnRH antagonists. This discrepancy may arise due to the significant detrimental effect of low LH levels on the LBRs after fresh embryo transfers.

Administration of a single dose of 300 IU of human chorionic gonadotropin seven days after the onset of estrus improves pregnancy rate in dairy goats by an unknown mechanism

This study examined the effects of exogenous hCG administration on ovarian function and pregnancy rates in estrous-induced dairy goats during the transition into the breeding season. Eighty-six Toggenburg does received 60 mg of medroxyprogesterone acetate intravaginal sponge for 6 d plus 200 IU of equine chorionic gonadotropin and 30 μg of d-cloprostenol i.m. 24 h before sponge removal, and were then bred for 96 h. Seven days (D7) after first mating the does received either 1 mL of saline (the control group, n = 43) or 300 IU of hCG (the hCG-treated group, n = 43) i.m. Transrectal ovarian ultrasonography (B-mode and color Doppler) was performed on D7, D13, D17, and D21 and ultrasonographic pregnancy detection on D30. Pregnancy rate was higher (P < 0.05) in hCG-treated goats (90.7%; 39/43) than that in control animals (74.4%; 32/43). Accessory luteal structures (ALSs) were detected in 46.5% (20/43) of hCG-treated does. All hCG-treated does that had ALSs and 82.6% of goats without ALS post-treatment remained pregnant. The total luteal area increased (P < 0.05) from D7 to D13 in pregnant animals of both groups, whereas mean vascular area declined (P < 0.05) by D21 in all nonpregnant does. Serum progesterone concentrations increased (P < 0.05) on D21 in pregnant goats of both groups, but they were related to changes in luteal tissue content only in control does throughout the present study. Mean daily numbers of small- and medium-sized antral follicles decreased (P < 0.05) only in pregnant animals of both groups with a decline in medium follicle numbers occurring earlier in hCG-treated (D13) compared with control does (D17). To summarize, a single dose of hCG given on D7 after estrus was followed by a decrease in the number of medium-sized antral follicles in gestating hCG-treated does, induced the formation of ALSs in ~47% of all hCG-treated does, and significantly increased the pregnancy rate in estrous-induced Toggenburg goats in the transition to the breeding season.

DNA Methylation Profiles Suggest Intergenerational Transfer of Maternal Effects

The view of maternal effects (nongenetic maternal environmental influence on offspring phenotype) has changed from one of distracting complications in evolutionary genetics to an important evolutionary mechanism for improving offspring fitness. Recent studies have shown that maternal effects act as an adaptive mechanism to prepare offspring for stressful environments. Although research into the magnitude of maternal effects is abundant, the molecular mechanisms of maternal influences on offspring phenotypic variation are not fully understood. Despite recent work identifying DNA methylation as a potential mechanism of nongenetic inheritance, currently proposed links between DNA methylation and parental effects are indirect and primarily involve genomic imprinting. We combined a factorial breeding design and gene-targeted sequencing methods to assess inheritance of methylation during early life stages at 14 genes involved in growth, development, metabolism, stress response, and immune function of Chinook salmon (Oncorhynchus tshawytscha). We found little evidence for additive or nonadditive genetic effects acting on methylation levels during early development; however, we detected significant maternal effects. Consistent with conventional maternal effect data, maternal effects on methylation declined through development and were replaced with nonadditive effects when offspring began exogenous feeding. We mapped methylation at individual CpG sites across the selected candidate genes to test for variation in site-specific methylation profiles and found significant maternal effects at selected CpG sites that also declined with development stage. While intergenerational inheritance of methylated DNA is controversial, we show that CpG-specific methylation may function as an underlying molecular mechanism for maternal effects, with important implications for offspring fitness.

Follicle-stimulating hormone administration affects amino acid metabolism in mammalian oocytes†

Culture media used in assisted reproduction are commonly supplemented with gonadotropin hormones to support the nuclear and cytoplasmic maturation of in vitro matured oocytes. However, the effect of gonadotropins on protein synthesis in oocytes is yet to be fully understood. As published data have previously documented a positive in vitro effect of follicle-stimulating hormone (FSH) on cytoplasmic maturation, we exposed mouse denuded oocytes to FSH in order to evaluate the changes in global protein synthesis. We found that dose-dependent administration of FSH resulted in a decrease of methionine incorporation into de novo synthesized proteins in denuded mouse oocytes and oocytes cultured in cumulus-oocyte complexes. Similarly, FSH influenced methionine incorporation in additional mammalian species including human. Furthermore, we showed the expression of FSH-receptor protein in oocytes. We found that major translational regulators were not affected by FSH treatment; however, the amino acid uptake became impaired. We propose that the effect of FSH treatment on amino acid uptake is influenced by FSH receptor with the effect on oocyte metabolism and physiology.

Fertility Preservation Using GnRH Agonists: Rationale, Possible Mechanisms, and Explanation of Controversy

The only clinically accepted method of fertility preservation in young women facing gonadotoxic chemo- and/or radiotherapy for malignant or autoimmune diseases is cryopreservation of embryos or unfertilized ova, whereas cryopreservation of ovarian tissue for future reimplantation, or in vitro maturation of follicles, and the use of gonadotropin-releasing hormone agonists (GnRHa) are still considered investigational, by several authorities. Whereas previous publications have raised the fear of GnRHa's possible detrimental effects in patients with hormone receptor-positive breast cancers, recent randomized controlled trials (RCTs) have shown that it either improves or does not affect disease-free survival (DFS) in such patients. This review summarizes the pros and cons of GnRHa co-treatment for fertility preservation, suggesting 5 theoretical mechanisms for GnRHa action: (1) simulating the prepubertal hypogonadotropic milieu, (2) direct effect on GnRH receptors, (3) decreased ovarian perfusion, (4) upregulation of an ovarian-protecting molecule such as sphingosine-1-phosphate, and (5) protecting a possible germinative stem cell. We try to explain the reasons for the discrepancy between most publications that support the use of GnRHa for fertility preservation and the minority of publications that did not support its efficiency.

Novel Concepts for Inducing Final Oocyte Maturation in In Vitro Fertilization Treatment

Infertility affects one in six of the population and increasingly couples require treatment with assisted reproductive techniques. In vitro fertilization (IVF) treatment is most commonly conducted using exogenous FSH to induce follicular growth and human chorionic gonadotropin (hCG) to induce final oocyte maturation. However, hCG may cause the potentially life-threatening iatrogenic complication "ovarian hyperstimulation syndrome" (OHSS), which can cause considerable morbidity and, rarely, even mortality in otherwise healthy women. The use of GnRH agonists (GnRHas) has been pioneered during the last two decades to provide a safer option to induce final oocyte maturation. More recently, the neuropeptide kisspeptin, a hypothalamic regulator of GnRH release, has been investigated as a novel inductor of oocyte maturation. The hormonal stimulus used to induce oocyte maturation has a major impact on the success (retrieval of oocytes and chance of implantation) and safety (risk of OHSS) of IVF treatment. This review aims to appraise experimental and clinical data of hormonal approaches used to induce final oocyte maturation by hCG, GnRHa, both GnRHa and hCG administered in combination, recombinant LH, or kisspeptin. We also examine evidence for the timing of administration of the inductor of final oocyte maturation in relationship to parameters of follicular growth and the subsequent interval to oocyte retrieval. In summary, we review data on the efficacy and safety of the major hormonal approaches used to induce final oocyte maturation in clinical practice, as well as some novel approaches that may offer fresh alternatives in future.

Superovulation alters DNA methyltransferase protein expression in mouse oocytes and early embryos

PURPOSE

DNA methylation is an epigenetic mechanism that plays critical roles during mammalian oocyte and preimplantation embryo development. It is achieved by adding a methyl group to the fifth carbon atom of cytosine residues within cytosine-phosphate-guanine (CpG) and non-CpG dinucleotide sites using DNA methyltransferase (DNMT) enzymes for de novo and maintenance methylation processes. DNMT1, DNMT3A, and DNMT3B play important roles in establishing methylation of developmentally related genes in oocytes and early embryos. The purpose of this study is to identify the effect of superovulation on the expression and subcellular localizations of these three DNMT enzymes in the mouse oocytes and early embryos.

METHODS

Three groups composed of control, normal dose [5 IU pregnant mare serum gonadotropin (PMSG) and 5 IU human chorionic gonadotropin (hCG)], and high dose [7.5 IU PMSG and 7.5 IU hCG] were created from 4-5-week-old female BALB/c mice. The relative expression and subcellular localizations of the DNMT proteins in the control and experiment groups have been characterized by using immunofluorescence staining subsequently analyzed in detailed.

RESULTS

DNMT1, DNMT3A, and DNMT3B protein expression in the germinal vesicle and metaphase II oocytes and in one-cell and two-cell embryos differed significantly when some of the normal- and high-dose groups were compared with the control counterparts.

CONCLUSION

This study has demonstrated for the first time that superovulation alters expression levels of the DNMT proteins, a finding that indicates that certain developmental defects in superovulated oocytes and early embryos may result from impaired DNA methylation processes.

Superovulation alters embryonic poly(A)-binding protein (Epab) and poly(A)-binding protein, cytoplasmic 1 (Pabpc1) gene expression in mouse oocytes and early embryos

Embryonic poly(A)-binding protein (EPAB) and poly(A)-binding protein, cytoplasmic 1 (PABPC1) play critical roles in translational regulation of stored maternal mRNAs required for proper oocyte maturation and early embryo development in mammals. Superovulation is a commonly used technique to obtain a great number of oocytes in the same developmental stages in assisted reproductive technology (ART) and in clinical or experimental animal studies. Previous studies have convincingly indicated that superovulation alone can cause impaired oocyte maturation, delayed embryo development, decreased implantation rate and increased postimplantation loss. Although how superovulation results in these disturbances has not been clearly addressed yet, putative changes in genes related to oocyte and early embryo development seem to be potential risk factors. Thus, the aim of the present study was to determine the effect of superovulation on Epab and Pabpc1 gene expression. To this end, low- (5IU) and high-dose (10IU) pregnant mare's serum gonadotropin (PMSG) and human chorionic gonadotrophin (hCG) were administered to female mice to induce superovulation, with naturally cycling female mice serving as controls. Epab and Pabpc1 gene expression in germinal vesicle (GV) stage oocytes, MII oocytes and 1- and 2-cell embryos collected from each group were quantified using quantitative reverse transcription-polymerase chain reaction. Superovulation with low or high doses of gonadotropins significantly altered Epab and Pabpc1 mRNA levels in GV oocytes, MII oocytes and 1- and 2-cell embryos compared with their respective controls (P<0.05). These changes most likely lead to variations in expression of EPAB- and PABPC1-regulated genes, which may adversely influence the quality of oocytes and early embryos retrieved using superovulation.

A novel follicle-stimulating hormone receptor mutation causing primary ovarian failure: a fertility application of whole exome sequencing

STUDY QUESTION

Can whole exome sequencing (WES) and in vitro validation studies be used to find the causative genetic etiology in a patient with primary ovarian failure and infertility?

SUMMARY ANSWER

A novel follicle-stimulating hormone receptor (FSHR) mutation was found by WES and shown, via in vitro flow cytometry studies, to affect membrane trafficking.

WHAT IS KNOWN ALREADY

WES may diagnose up to 25-35% of patients with suspected disorders of sex development (DSD). FSHR mutations are an extremely rare cause of 46, XX gonadal dysgenesis with primary amenorrhea due to hypergonadotropic ovarian failure.

STUDY DESIGN, SIZE, DURATION

A WES study was followed by flow cytometry studies of mutant protein function.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study subjects were two Turkish sisters with hypergonadotropic primary amenorrhea, their parents and two unaffected sisters. The affected siblings and both parents were sequenced (trio-WES). Transient transfection of HEK 293T cells was performed with a vector containing wild-type FSHR as well as the novel FSHR variant that was discovered by WES. Cellular localization of FSHR protein as well as FSH-stimulated cyclic AMP (cAMP) production was evaluated using flow cytometry.

MAIN RESULTS AND THE ROLE OF CHANCE

Both affected sisters were homozygous for a previously unreported missense mutation (c.1222G>T, p.Asp408Tyr) in the second transmembrane domain of FSHR. Modeling predicted disrupted secondary structure. Flow cytometry demonstrated an average of 48% reduction in cell-surface signal detection (P < 0.01). The mean fluorescent signal for cAMP (second messenger of FSHR), stimulated by FSH, was reduced by 50% in the mutant-transfected cells (P < 0.01).

LIMITATIONS, REASONS FOR CAUTION

This is an in vitro validation. All novel purported genetic variants can be clinically reported only as 'variants of uncertain significance' until more patients with a similar phenotype are discovered with the same variant.

WIDER IMPLICATIONS OF THE FINDINGS

We report the first WES-discovered FSHR mutation, validated by quantitative flow cytometry. WES is a valuable tool for diagnosis of rare genetic diseases, and flow cytometry allows for quantitative characterization of purported variants. WES-assisted diagnosis allows for treatments aimed at the underlying molecular etiology of disease. Future studies should focus on pharmacological and assisted reproductive treatments aimed at the disrupted FSHR, so that patients with FSH resistance can be treated by personalized medicine.

STUDY FUNDING/COMPETING INTERESTS

E.V. is partially funded by the DSD Translational Research Network (NICHD 1R01HD068138). M.S.B. is funded by the Neuroendocrinology, Sex Differences and Reproduction training grant (NICHD 5T32HD007228). The authors have no competing interests to disclose.

Effects of GnRH agonists on the expression of developmental follicular anti-mullerian hormone in varying follicular stages in cyclic mice in vivo

Gonadotrophin‑releasing hormone (GnRH) agonists (GnRHa) have been widely used to induce a state of downregulation for in vitro fertilization, and its direct effects on the pituitary are well known. However, the effects of GnRHa on the expression of anti‑mullerian hormone (AMH) by follicles in varying stages in vivo remain to be fully elucidated. In the present study 84 cyclic mice were randomly divided equally into four GnRHa groups and three cyclic mice were used as a control group. The expression levels of AMH in follicles of varying stages between days 0 and 7 following GnRHa administration were quantified using immunohistochemistry. The expression of AMH in follicles at various stages revealed dynamic changes during the process of downregulation. AMH in primary follicles initially increased and then decreased gradually. In small and large preantral follicles and in granulosa cells (GCs) surrounding the oocyte of small antral follicles, the expression of AMH began to increase on day 1, was attenuated on day 2, and then increased to a peak. The expression levels of AMH in the GCs surrounding the basement membrane, in contrast to the GCs surrounding the oocyte, were significantly lower and did not increase on day 1. In all stages of follicles, the expression of AMH declined gradually between the peak level and last day of downregulation. On day 7, the varying follicular stages all expressed lower levels of AMH than on day 0. This decrease was more prominent in the higher dose groups, compared with the lower dose groups. In conclusion, GnRHa was observed to induce time‑dependent changes in the expression of AMH at varying follicular stages, which occurred in a dose‑dependent manner.

Soluble ligands and their receptors in human embryo development and implantation

Extensive evidence suggests that soluble ligands and their receptors mediate human preimplantation embryo development and implantation. Progress in this complex area has been ongoing since the 1980s, with an ever-increasing list of candidates. This article specifically reviews evidence of soluble ligands and their receptors in the human preimplantation stage embryo and female reproductive tract. The focus will be on candidates produced by the human preimplantation embryo and those eliciting developmental responses in vitro, as well as endometrial factors related to implantation and receptivity. Pathways to clinical translation, including innovative diagnostics and other technologies, are also highlighted, drawing from this collective evidence toward facilitating joint improvements in embryo quality and endometrial receptivity. This strategy could not only benefit clinical outcomes in reproductive medicine but also provide broader insights into the peri-implantation period of human development to improve fetal and neonatal health.

Molecular characterization of the Chinese alligator follicle-stimulating hormone β subunit (FSHβ) and its expression during the female reproductive cycle

The Chinese alligator Alligator sinensis is an endangered species endemic to China, it has a highly specialized reproductive pattern with low fecundity. Up to date, little is known about the regulation of its female reproductive cycle. Follicle-stimulating hormone (FSH), a glycoprotein hormone, plays a key role in stimulating and regulating ovarian follicular development and egg production. In this study, the complete FSHβ cDNA from the ovary of the Chinese alligator was obtained for the first time, it consists of 843-bp nucleotides, including 120-bp nucleotides of the 5'-untranslated region (UTR), 396-bp of the open reading frame, and 3'-UTR of 327-bp nucleotides. It encodes a 131-amino acid precursor molecule of FSHβ with a signal peptide of 18 amino acids followed by a mature protein of 113 amino acids. Its deduced amino acid sequence shares high identities with the American alligator (100%) and birds (89-92%). Phylogenetic tree analysis of the FSHβ amino acid sequence indicated that alligators cluster into the bird branch. Tissue distribution analyses indicated that FSHβ mRNA is expressed in ovary, intestine and liver with the highest level in the ovary, while not in stomach, pancreas, heart, thymus and thyroid. Expression of FSHβ in ovary increases in May (breeding prophase) and peaks in July (breeding period), it is maintained at high levels through September, then decreases significantly in November (post-reproductive period) and remains relatively low from January to March (hibernating period). These temporal changes of FSHβ expression implicated that it might play an important role in promoting ovarian development during the female reproductive cycle.

Detection of RUNX2 gene expression in cumulus cells in women undergoing controlled ovarian stimulation

BACKGROUND

RUNX2 is a transcription factor, whose expression has been recently identified in the mouse ovary. Regulation of RUNX2 expression and its function in the human ovary have not been determined yet. The aim of the present study is the investigation of the possible correlation between RUNX2 gene expression in cumulus cells and controlled ovarian stimulation and pregnancy outcomes after ART treatment.

METHODS

A total of 41 patients undergoing ICSI treatment for male factor infertility were enrolled into a specific ART program, during which cumulus cells were collected. The expression of RUNX2 gene in cumulus cells was examined by real-time PCR.

RESULTS

Concerning RUNX2 gene expression, 12 out of 41 women were detected with RUNX2 expression, with ratios ranging from 0.84 to 1.00, while 28 out of 41 women had no expression (ratio = 0). Only 1 woman presented a weak RUNX2 gene expression (ratio = 0.52). From 8 women that proceeded to pregnancy, 7 of them did not express RUNX2 gene in cumulus cells, while one was the woman with weak gene expression that also achieved pregnancy. The group of women without RUNX2 expression presented higher number of follicles (p = 0.013), higher number of retrieved oocytes (p = 0.016), higher basal LH serum levels (p = 0.016) and higher peak estradiol levels (p = 0.013), while the number of fertilized oocytes differed marginally between the two groups (p = 0.089). Moreover, RUNX2 expression was negatively associated with LH levels (OR = 0.22, p = 0.021) and E2 levels (OR = 0.25, p = 0.026).

CONCLUSIONS

Consequently, based on the preliminary findings of the present pilot study a potential inhibitory mechanism of RUNX2 gene is observed in the ovary when high mRNA levels are detected, suggesting that RUNX2 could possibly be used as a candidate genetic marker in the monitoring of the outcome of an ART treatment.

LH receptor gene expression in cumulus cells in women entering an ART program

PURPOSE

Luteinizing hormone (LH) exerts its actions through its receptor (LHR), which is mainly expressed in theca cells and to a lesser extent in oocytes, granulosa and cumulus cells. The aim of the present study was the investigation of a possible correlation between LHR gene and LHR splice variants expression in cumulus cells and ovarian response as well as ART outcome.

METHODS

Forty patients undergoing ICSI treatment for male factor infertility underwent a long luteal GnRH-agonist downregulation protocol with a fixed 5-day rLH pre-treatment prior to rFSH stimulation and samples of cumulus cells were collected on the day of egg collection. RNA extraction and cDNA preparation was followed by LHR gene expression investigation through real-time PCR. Furthermore, cumulus cells were investigated for the detection of LHR splice variants using reverse transcription PCR.

RESULTS

Concerning LHR expression in cumulus cells, a statistically significant negative association was observed with the duration of ovarian stimulation (odds ratio = 0.23, p = 0.012). Interestingly, 6 over 7 women who fell pregnant expressed at least two specific types of LHR splice variants (735 bp, 621 bp), while only 1 out of 19 women that did not express any splice variant achieved a pregnancy.

CONCLUSIONS

Consequently, the present study provide a step towards a new role of LHR gene expression profiling as a biomarker in the prediction of ovarian response at least in terms of duration of stimulation and also a tentative role of LHR splice variants expression in the prediction of pregnancy success.

FSH stimulates lipid biosynthesis in chicken adipose tissue by upregulating the expression of its receptor FSHR

Transcripts and protein for follicle-stimulating hormone receptor (FSHR) were demonstrated in abdominal adipose tissue of female chickens. There was no expression of the Fsh gene, but FSH and FSHR colocalized, suggesting that FSH was receptor bound. Partial correlations indicted that changes in abdominal fat (AF) content were most directly correlated with Fshr mRNA expression, and the latter was directly correlated with tissue FSH content. These relationships were consistent with FSH inducing Fshr mRNA expression and with the finding that FSH influenced the accumulation of AF in chickens, a novel role for the hormone. Chicken preadipocytes responded linearly to doubling concentrations of FSH in Fshr mRNA expression and quantities of FSHR and lipid, without discernable effect on proliferation. Cells exposed to FSH more rapidly acquired adipocyte morphology. Treatment of young chickens with chicken FSH (4 mIU/day, subcutaneous, days 7-13) did not significantly decrease live weight but increased AF weight by 54.61%, AF as a percentage of live weight by 55.45%, and FSHR transcripts in AF by 222.15% (2 h after injection). In cells stimulated by FSH, genes related to lipid metabolism, including Rdh10, Dci, RarB, Lpl, Acsl3, and Dgat2, were expressed differentially, compared with no FSH. Several pathways of retinal and fatty acid metabolism, and peroxisome proliferator-activated receptor (PPAR) signaling changed. In conclusion, FSH stimulates lipid biosynthesis by upregulating Fshr mRNA expression in abdominal adipose tissue of chickens. Several genes involved in fatty acid and retinal metabolism and the PPAR signaling pathway mediate this novel function of FSH.

Extrapituitary production of anterior pituitary hormones: an overview

Protein hormones from the anterior pituitary gland have well-established endocrine roles in their peripheral target glands. It is, however, now known that these proteins are also produced within many of their target tissues, in which they act as local autocrine or paracrine factors, with physiological and/or pathophysiological significance. This emerging concept is the focus of this brief review.

Gonadotropins up-regulate the expression of enolase 2, but not enolase 1, in the rat ovary

It has been demonstrated that the glycolytic enzymes, enolase 1 (ENO1) and enolase 2 (ENO2), are expressed in the rat ovary. In the present study, we found that mRNA levels of ovarian ENO2 but not ENO1 in normal cycling adult female rats changed significantly during the estrous cycle: ovarian ENO2 mRNA levels at metestrus were lower than those at estrus. Single injection of human CG (hCG) or equine CG (eCG) into immature (3 week old) rats up-regulated ovarian expression of ENO2. hCG mainly increased ENO2 expression in oocytes and theca cells of preantral and antral follicles, and eCG did in theca cells of these follicles. In contrast, hCG and eCG did not affect the expression of ENO1, which was mainly expressed in granulosa cells. These results suggest that endogenous gonadotropins up-regulate expression of ENO2 in oocytes and theca cells of preantral and antral follicles, which would activate glycolysis in these cells. It is also suggested that the activated glycolysis is necessary for ovarian functions such as follicle growth and maturation, and hormone production.

Human ovarian follicular development: from activation of resting follicles to preovulatory maturation

By integrating morphometrical and endocrinological data, as well as biological effects of various molecules synthesized by the human follicle, we propose a dynamic view of the follicle growth within the human ovary. Folliculogenesis starts with entry of resting follicles into the growth phase, a process where the kit system plays a key role. Several months are required for a new growing follicle to reach the preantral stage (0.15mm), then 70 additional days to reach the size of 2mm. Early growing follicle growth is regulated by subtle interactions between follicle-stimulating hormone (FSH) and local factors produced by theca and granulosa cells (GCs), as well as the oocyte. From the time they enter the selectable stage during the late luteal phase, follicles become sensitive to cyclic changes of FSH in terms of granulosa cell proliferation. During the early follicular phase, the early selected follicle grows very quickly and estradiol is present in the follicular fluid. However, the total steroid production remains moderate. From the mid-follicular phase, the preovulatory follicle synthesizes high quantities of estradiol, then after the mid-cycle gonadotropin surge, very large amounts of progesterone. At this stage of development, the responsiveness of the follicle to gonadotropins is maximum, especially to luteinizing hormone (LH) that triggers granulosa wall dissociation and cumulus expansion as well as oocyte nuclear maturation. Thus, as the follicle develops, its responsiveness to gonadotropins progressively increases under the control of local factors acting in an autocrine/paracrine fashion.

Spindle and chromosome configurations of human oocytes matured in vitro in two different culture media

In-vitro maturation can have deleterious effects on spindle formation and proper chromosome alignment in human oocytes and can be profoundly affected by culture conditions. This study compared the spindle presence and location with the maturation rate of germinal vesicle (GV) oocytes cultured in two different media: G1.2 and G1.2 supplemented with follicle-stimulating hormone, human chorionic gonadotrophin and 17beta-oestradiol. A total of 304 oocytes were retrieved from 101 women undergoing IVF treatment with intracytoplasmic sperm injection. Spindle presence was recorded using the Polscope. Spindle morphology was evaluated with immunocytological staining for alpha-tubulin and chromatin. Twenty-one in-vitro matured oocytes with the presence of spindle and ten of their corresponding polar bodies (PB) were also assessed for aneuploidy. A significantly increased maturation rate (69.7%) was observed after 24h in the supplemented culture media compared with the G1.2 media (56.6%; P<0.05). The proportions of metaphase II (MII) oocytes with spindle presence and abnormal spindle morphology were similar in the two culture media. Also, 76.9% of MII and 70% of PB had chromosomal abnormalities. In conclusion, supplementing culture media may increase the oocyte maturation rate in vitro, but does not necessarily indicate the presence of a birefringent spindle, or normal spindle and chromosomal alignment.

Early hCG addition to rFSH for ovarian stimulation in IVF provides better results and the cDNA copies of the hCG receptor may be an indicator of successful stimulation

A simple, safe and cost-effective treatment protocol in ovarian stimulation is of great importance in IVF practice, especially in the case of previous unsuccessful attempts. hCG has been used as a substitute of LH because of the degree of homology between the two hormones. The main aim of this prospective randomized study was to determine, for the first time, whether low dose hCG added to rFSH for ovarian stimulation could produce better results compared to the addition of rLH in women entering IVF-ET, especially in those women that had previous IVF failures. An additional aim was to find an indicator that would allow us to follow-up ovarian stimulation and, possibly, modify it in order to achieve a better IVF outcome; and that indicator may be the cDNA copies of the LH/hCG receptor. Group A patients (n = 58) were administered hCG and Group B rLH (n = 56) in addition to rFSH in the first days of ovarian stimulation. The number of follicles and oocytes and, most importantly, implantation and pregnancy rates were shown to be statistically significantly higher in the hCG group. This study has also determined, for the first time to our best knowledge, m-RNA for LH/hCG receptors in the lymphocytes of peripheral blood 40 h before ovum pick-up. cDNA levels of the hCG receptor after ovarian stimulation were significantly higher among women receiving hCG compared to those receiving LH. In addition, higher levels were encountered among women with pregnancy compared to those without, although this was not statistically significant due to the small number of pregnancies. It seems that hCG permits a highly effective and more stable occupancy of rLH/hCG receptors and gives more follicles and more oocytes. The determination of cDNA copies could be, in the future, a marker during ovulation induction protocols and of course a predictor for the outcome of ART in the special subgroup of patients with previous failures.

GnRH-analogues and oral contraceptives for fertility preservation in women during chemotherapy

BACKGROUND

For preserving fertility in women during chemotherapy, the character of invasive techniques, such as ovarian cryopreservation and other techniques, await further experience. Meanwhile, non-invasive techniques have attempted to minimize the gonadotoxic effect of chemotherapy, by using gonadotrophin-releasing hormone-analogues (GnRH-a) or oral contraceptives (OC).

METHODS

We performed a computerized MEDLINE search to identify articles published on fertility preservation using GnRH-a or OCs.

RESULTS

Nine human-controlled studies reported the use of GnRH-a and four reported the use of OCs in parallel to chemotherapy. All nine studies analysing the effect of GnRH-a found lower rates of premature ovarian failure (POF) in patients receiving GnRH-a compared with the controls. Summarizing the studies resulted in 11.1% incidence of POF in patients who received GnRH-a compared with 55.5% incidence in the controls. Evidence using the fertility preserving effect of OC is limited. Two studies showed lower POF rates in OC-treated patients. The summarized data revealed a POF rate of 13.2% in patients who received OCs compared with that of 29.8% in the controls.

CONCLUSIONS

The published clinical studies provide evidence, but do not prove statistically, that GnRH-a co-treatment reduces gonadotoxicity. Owing to the retrospective and non-randomized nature of most of the studies, definite conclusions concerning the reduction of POF by GnRH-a can still not be unequivocally drawn. As GnRH-a and OC have no serious side effects and as GnRH-a can even reduce chemotherapy-induced complications, such as severe menometrorrhagia, GnRH-a are considered by many clinicians as a clinically useful co-treatment in chemotherapy. The published clinical studies on OC also suggest a possible effect on the reduction of POF under certain conditions.

Developmental competence of immature and failed/abnormally fertilized human oocytes in nuclear transfer

Somatic cell nuclear transfer holds great promise for basic studies of reprogramming human somatic cells and for the potential development of novel cell-based therapeutics. The aim of this study was to examine experimental aspects of human nuclear transfer via use of an abundant source of oocytes, those that are routinely discarded from assisted reproduction clinics. The results suggest and reinforce several findings based on the analysis of multiple parameters: first, it was observed that supplementation of commercial culture media with hormones promoted embryo development after parthenogenetic activation. Second, the use of the chemical activation reagent puromycin resulted in significant differences in cleavage rates in oocytes that were failed/abnormally fertilized after intracytoplasmic sperm injection relative to those from IVF (P < 0.05). Third, cycloheximide promoted cleavage rates >/=40% in both groups of oocytes; moreover, two blastocysts were produced following cycloheximide treatment. Finally, the use of a subset of oocytes for nuclear transfer resulted in cleaved embryos that expressed green fluorescent protein from a transgene in donor nuclei from human embryonic stem cells. In light of these results, it is suggested that the discarded oocytes can be used to investigate new human nuclear transfer protocols for embryonic stem cell derivation.

Gonadotropin-releasing hormone agonist decreases chemotherapy-induced gonadotoxicity and premature ovarian failure in young female patients with Hodgkin lymphoma

OBJECTIVE

To minimize the gonadotoxic effect of chemotherapy by the cotreatment with a GnRH agonistic analogue (GnRH-a).

DESIGN

Prospective nonrandomized study with concurrent and historical controls.

SETTING

University medical center.

PATIENT(S)

One hundred fifteen female patients with Hodgkin lymphoma (HL).

INTERVENTION(S)

Sixty-five patients received a monthly injection of GnRH-a, administered before starting chemotherapy until its conclusion, up to a maximum of 6 months. Thirty-five patients were treated with ABVD and 76 with a procarbazine-containing regimen. This group was compared with a control group of 46 women who were treated concurrently with similar chemotherapy (n = 26) without GnRH-a or were historical controls (n = 20).

MAIN OUTCOME MEASURE(S)

Cyclic ovarian function (COF) versus premature ovarian failure (POF).

RESULT(S)

The ovarian function could be determined in 111 patients. In the GnRH-a/chemotherapy group, 63 out of 65 patients resumed ovulation and regular menses (96.9 %), compared with 63% of the 46 control subjects. Twenty of the 22 patients in the BEACOPP/escalated BEACOPP/GnRH-a cotreatment resumed cyclic ovarian function versus 9 of the 14 in the chemotherapy-only group. All 17 MOPP/ABV/GnRH-a cotreated patients resumed COF versus 11 of the 22 in the chemotherapy-only group. There was no significant effect of the GnRH-a cotreatment regarding COF in the ABVD group. There were no significant differences in the cumulative doses of the various alkylating agents between the two groups.

CONCLUSION(S)

Cotreatment with GnRH-a may reduce ovarian damage significantly in female patients treated for HL and should be considered in addition to assisted reproduction for women in reproductive age receiving gonadotoxic chemotherapy.

How to preserve fertility in young women exposed to chemotherapy? The role of GnRH agonist cotreatment in addition to cryopreservation of embrya, oocytes, or ovaries

The possibilities to preserve fertility in women exposed to chemotherapy are: in vitro fertilization plus embryo cryopreservation, ovarian cryopreservation, unfertilized ova cryopreservation, and the administration of a gonadotropin-releasing hormone (GnRH) agonist. Because none of these methods is ideal, combination of several methods should be considered. Because the chances of preserving gonadal function following combined-modality treatment are significantly better for girls than for boys, simulation of a prepubertal milieu was applied only to women of reproductive age. The administration of GnRH agonists to women with Hodgkin's disease, breast cancer, and other malignancies, or to patients with lupus nephropathy, in parallel with chemotherapy, by others and by us, has demonstrated a significantly lower rate of premature ovarian failure in survivors than in nonrandomized controls. Several prospective, randomized studies are ongoing. A recent meta-analysis found that the administration of a GnRH agonist, in addition to chemotherapy, to patients with breast cancer was associated with less recurrence and superior survival. Several possibilities to explain the beneficial effect of GnRH agonists to minimize chemotherapy-associated gonadotoxicity are suggested: (a) The hypogonadotropic milieu decreases the number of primordial follicles entering the differentiation stage, which is more vulnerable to chemotherapy; (b) The hypoestrogenic state decreases ovarian perfusion and delivery of chemotherapy to the ovaries; (c) A direct effect of the GnRH agonist on the ovary occurs independently of the gonadotropin level; (d) GnRH agonists may upregulate an intragonadal antiapoptotic molecule such as sphingosine-1-phosphate; (e) The GnRH agonist may protect ovarian germline stem cells.

Absence of conclusive evidence for the safety and efficacy of gonadotropin-releasing hormone analogue treatment in protecting against chemotherapy-induced gonadal injury

Every year, an increasing number of women with malignant and nonmalignant diseases is successfully treated with cytotoxic chemotherapy and/or radiotherapy. Many of these patients suffer from infertility and gonadal failure as a result of these treatments. At present, these patients may resort to assisted-reproduction techniques to protect their future childbearing potential before the implementation of cytotoxic therapy. While embryo cryopreservation is an established technology, oocyte and ovarian tissue freezing techniques are still investigational. Nevertheless both of these techniques have resulted in live births. Apart from assisted-reproduction techniques, it has been extensively debated whether administration of gonadotropin-releasing hormone (GnRH) analogues in conjunction with chemotherapy can protect ovarian reserve against cytotoxic insult. In this manuscript, we debate the rationale for the effectiveness of GnRH analogue coadministration in preservation of fertility by reviewing the literature, and provide preliminary data to support our views.

Identifying new human oocyte marker genes: a microarray approach

The efficacy of classical IVF techniques is still impaired by poor implantation and pregnancy rates after embryo transfer. This is mainly due to a lack of reliable criteria for the selection of embryos with sufficient development potential. Several studies have provided evidence that some gene expression levels could be used as objective markers of oocyte and embryo competence and capacity to sustain a successful pregnancy. These analyses usually use reverse transcription-polymerase chain reaction to look at small sets of pre-selected genes. However, microarray approaches allow the identification of a wider range of cellular marker genes which could include additional and perhaps more suitable genes that could serve as embryo selection markers. Microarray screenings of around 30,000 genes on U133P Affymetrix gene chips made it possible to establish the expression profile of these genes as well as other related genes in human oocytes and cumulus cells. This study identifies new potential regulators and marker genes such as BARD1, RBL2, RBBP7, BUB3 or BUB1B, which are involved in oocyte maturation.

Effect of Prolactin in the Absence of hCG on Maturation, Fertilization, and Embryonic Development of in Vitro Matured Mouse Oocytes

Oocyte maturation is a complex process involving both the progression of meiotic cycle and the reprogramming of cytoplasmic events. The aim of this study was to investigate the effects of prolactin (PRL) in the in vitro maturation (IVM) of preantral mouse oocytes, in the absence of human chorionic gonadotrophin (hCG). Mouse preantral follicles were collected from female mice without prior hormonal ovarian stimulation and were cultured in the presence of varying concentrations of PRL (20, 100, 200, and 300 ng/mL) for 12 days. A group of in vitro matured oocytes were assessed for polar body (PB) formation, while the rest were fertilized and embryonic development was recorded. The maturation of preantral mouse follicles, as well as their fertilization and cleavage rates, observed when the culture medium was supplemented with middle- and high-range doses of PRL was beneficially affected. This effect was considerably high, although the culture media lacked hCG, a hormone extensively used in modern ovulation induction regiments, as well as in IVM media.

Oocyte Maturation in Assisted Reproductive Techniques

Human oocyte maturation is a long process during which nuclear maturation occurs resulting in germinal vesicle breakdown (transition from prophase I to metaphase II) and extrusion of the first polar body. During oocyte maturation, in parallel with nuclear maturation, a number of events take place in the oocyte cytoplasm that assist fertilization and early embryonic development. So far several attempts have been made to mature human oocytes in vitro. The main patient group to which in vitro maturation (IVM) has been applied is polycystic ovarian syndrome. In a concise review we present the techniques used for the IVM of oocytes and the role of hormones and growth factors in IVM and subsequent fertilization and early embryonic development.

Oocyte bone morphogenetic protein 15, but not growth differentiation factor 9, is increased during gonadotropin-induced follicular development in the immature mouse and is associated with cumulus oophorus expansion

Bone morphogenetic protein (BMP) 15 and growth differentiation factor (GDF) 9 are oocyte-secreted growth factors that are critical local regulators of ovarian function and may be involved in preovulatory cumulus expansion. As cumulus expansion occurs in response to the ovulatory surge, the present study was designed: 1) to investigate whether GDF9 and BMP15 are regulated by gonadotropins in the mouse ovary; and 2) to visualize changes in both GDF9 and BMP15 immunostaining in response to gonadotropins. Immature 21-day-old mice were sequentially treated with recombinant human FSH (r-hFSH), 5 IU daily, at Days 21, 22, and 23 of life, then injected with 5 IU hCG at Day 24 of life. In response to r-hFSH, steady-state Bmp15 mRNA expression levels increased in both total ovaries and cumulus-oocyte complexes, whereas Gdf 9 mRNA levels did not. In addition, BMP15 protein levels increased in total ovaries. The GDF9 immunostaining was exclusively seen in growing oocytes in both control and gonadotropin-treated mice, whereas that of BMP15, which was also primarily seen in growing oocytes, exhibited important changes in response to gonadotropins. Strong BMP15 immunostaining was observed in the follicular fluid of atretic antral follicles after FSH treatment and in expanded, but not in compact, cumulus cells after hCG. The present results show for the first time that BMP15 levels increase during gonadotropin-induced follicular development, in parallel with oocyte maturation, and that this local factor is likely involved in cumulus expansion as previously suggested by studies in Bmp15-null mice.

FSH receptor gene polymorphisms have a role for different ovarian response to stimulation in patients entering IVF/ICSI-ET programs

PURPOSE

To examine the frequency distribution of the Ser680Asn polymorphism of the follicle-stimulating hormone receptor (FSHR) gene in ovarian dysfunction (OD) infertile women, "poor responders" (PR) and "good responders" (GR).

METHODS

The hormonal profiles and treatment of all patients were analyzed and FSHR polymorphism was examined by PCR and RFLP. Women from all groups were classified as Asn/Asn, Asn/Ser, and Ser/Ser genotypes.

RESULTS

The frequency distribution of Ser/Ser, Asn/Ser and Asn/Asn variants in OD patients was 45.5, 22.7, and 31.8%, respectively. Day 3 FSH levels in OD and GR patients were higher in Ser/Ser and Asn/Asn subgroups. Asn/Ser carriers from OD and GR groups provided more follicles and oocytes compared to other allelic variants.

CONCLUSIONS

GR patients carry more often the Asn/Ser genotype. The latter is correlated with more follicles and oocytes in both OD and GR patients. The Ser/Ser variant might be related to higher serum FSH levels, while the Asn/Ser with lower.

Association of abnormal morphology and altered gene expression in human preimplantation embryos

OBJECTIVE

We set out to characterize the expression of nine genes in human preimplantation embryos and determine whether abnormal morphology is associated with altered gene activity.

DESIGN

Reverse transcription and real-time polymerase chain reaction were used to quantify the expression of multiple genes in each embryo. The genes studied have various important cellular roles (e.g., cell cycle regulation, DNA repair, and apoptosis).

SETTING

Research laboratory working closely with a clinical IVF practice.

PATIENT(S)

Over 50 embryos were donated by infertile patients (various etiologies). Among these, all major stages of preimplantation development and a variety of common morphologic abnormalities were represented.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Quantification of mRNA transcripts.

RESULT(S)

We detected an association between certain forms of abnormal morphology and disturbances of gene activity. Cellular fragmentation was associated with altered expression of several genes, including TP53, suggesting that fragmenting blastomeres are suffering stress of a type monitored by p53, possibly as a consequence of suboptimal culture conditions.

CONCLUSION(S)

Appropriate gene expression is vital for the regulation of metabolic pathways and key developmental events. Our data indicates a possible causal relationship between changes in gene expression and the formation of clinically relevant abnormal embryo morphologies. We hypothesize that embryos with expression profiles characteristic of good morphology and appropriate for their developmental stage have the greatest potential for implantation. If confirmed, this could lead to a new generation of preimplantation genetic diagnosis (PGD) tests for assessing embryo viability and predicting implantation potential.

Evidence for cycle-dependent expression of follicle-stimulating hormone receptor in human endometrium

OBJECTIVE

It was the purpose of the present study to investigate whether human endometrium expresses follicle-stimulating hormone (FSH) receptor mRNA and peptide, and whether this expression is regulated in a cycle-dependent manner in endometrium derived from various phases of the menstrual cycle.

METHODS

FSH receptor mRNA and peptide expression were evaluated by reverse transcription-polymerase chain reaction and by immunohistochemistry in endometrium from 15 women undergoing hysteroscopy to evaluate the morphology of the uterine cavity or hysterectomy for leiomyomas.

RESULTS

FSH receptor mRNA was expressed by human endometrium, and its peptide was located immunohistochemically in both proliferative and secretory endometrial epithelial and stromal cells. A significant increase in immunoreactive FSH receptor was observed during the secretory phase.

CONCLUSIONS

We have shown the presence of FSH receptor in human endometrium and demonstrated that FSH receptor immunostaining is upregulated in the secretory phase of the menstrual cycle. The dynamic pattern of receptor expression indicates that FSH may play a role in the regulation of endometrial function and possibly in the embryo-endometrium interaction.

Follicle-stimulating hormone receptor gene mutations are not evident in Greek women with premature ovarian failure and poor responders

BACKGROUND/AIMS

This clinical and molecular study aimed to investigate the presence of follicle-stimulating hormone (FSH) receptor gene mutations in women with premature ovarian failure (POF) and poor responders to in vitro fertilization treatment.

METHODS

DNA was extracted from blood samples for subsequent polymerase chain reaction (PCR). PCR was followed by restriction fragment length polymorphism and direct sequencing.

RESULTS

No inactivating mutations reported so far were identified in exons 6, 7, and 10 in women with POF and poor responders.

CONCLUSION

FSH receptor gene mutations are not frequent in Greek patients with POF as is the case in the rest of the world except for cases with ovarian dysgenesis in Finland.

Developmental capability of denuded bovine oocyte in a co-culture system with intact cumulus-oocyte complexes: role of cumulus cells, cyclic adenosine 3',5'-monophosphate, and glutathione

Cumulus oophorus cells have been implicated in the regulation of female gamete development, meiotic maturation, and oocyte-sperm interaction. Nevertheless, the specific role of cumulus cells (CCs) during the final stages of oocyte maturation and fertilization processes still remains unclear. Several studies have been conducted in order to clarify the role of follicular cells using culture systems where denuded oocytes (DOs) were co-cultured with isolated CCs, or in the presence of conditioned medium. However, those attempts were ineffective and the initial oocyte competence to become a blastocyst after fertilization was only partially restored. Aim of the present study was to analyze the effect of the interactions between somatic cells and the female gamete on denuded oocyte developmental capability using a system of culture where CCs were present as dispersed CCs or as intact cumulus-oocyte complexes (COCs) in co-culture with oocytes freed of CC investment immediately after isolation from the ovary. Moreover, we analyzed the specific role of cyclic adenosine 3'-5' monophosphate (cAMP) and glutathione (GSH) during FSH-stimulated maturation of denuded oocyte co-cultured with intact COCs. Our data confirm that denuded oocyte has a scarce developmental capability, and the presence of dispersed CCs during in vitro maturation (IVM) does not improve their developmental competence. On the contrary, the co-presence of intact COCs during denuded oocyte IVM partially restores their developmental capability. The absence of CCs investment causes a drop of cAMP content in DOs at the beginning of IVM and the addition of a cAMP analog in the culture medium does not restore the initial oocyte developmental competence. The relative GSH content of denuded oocyte matured in presence of intact COCs is consistent with the partial recovery of their developmental capability. However, the complete restoration of a full embryonic developmental potential is achieved only when DOs are co-cultured with intact COCs during both IVM and in vitro fertilization (IVF). Our results suggest that the direct interaction between oocyte and CCs is not essential during IVM and IVF of denuded oocyte. We hypothesize that putative diffusible factor(s), produced by CCs and/or by the crosstalk between oocyte and CCs in the intact complex, could play a key role in the acquisition of developmental competence of the denuded female gamete.

Expression of genes regulating chromosome segregation, the cell cycle and apoptosis during human preimplantation development

BACKGROUND

Appropriate gene expression is vital for the regulation of developmental processes. Despite this fact there is a remarkable paucity of information concerning gene activity during preimplantation development.

METHODS

We employed reverse transcription and real-time fluorescent PCR to quantify the expression of nine genes (BRCA1, BRCA2, ATM, TP53, RB1, MAD2, BUB1, APC and beta-actin) in oocytes and embryos. A full characterization of all genes was achieved in 42 embryos and four oocytes. The genes analysed have a variety of important cellular functions.

RESULTS

Oocytes displayed relatively high levels of mRNA transcripts, while 2-3-cell embryos were seen to contain very little mRNA from any of the genes examined. Recovery of expression levels was not seen until the 4-cell stage or later, with the presumptive activation of the embryonic genome. Some genes displayed sharp increases in expression in embryos composed of 4-8 cells, but, for most, maximum expression was not achieved until the blastocyst stage.

CONCLUSIONS

Our data show that it is possible to define characteristic gene expression profiles for each stage of human preimplantation development. The identification of genes active at defined preimplantation phases may provide clues to the cellular pathways utilized at specific stages of development. Expression of genes that function in DNA repair pathways indicate that DNA damage may be common at the cleavage stage. We suggest that specific patterns of gene expression may be indicative of embryo implantation potential.

Human follicle-stimulating hormone receptor (FSH-R) promoter/enhancer activity is inhibited by transcriptional factors, from the upstream stimulating factors family, via E-box and newly identified initiator element (Inr) in FSH-R non-expressing cells

To localize the regulatory elements in the human follicle-stimulating hormone receptor (FSH-R) promoter/enhancer and to determine the role of upstream stimulatingfactors (USFs) in these elements, we transiently transfected constructs of FSH-R promoter/enhancer in pGL3 luciferase reporter plasmids into Chinese hamster ovary cells and the activities were determined by measuring luciferase luminescence of the cell lysates. The 5'-flanking regions of the human FSH-R gene from nt -1485 to -1 with respect to the gene translation start site were amplified by polymerase chain reaction (PCR) and subcloned in pGL3. Deletion mutants were created using PCR or restriction enzyme digestion. Mutation in the E-box sequence from nt -124 to -119 (E-box 3), in the construct from -224 to nt -1 or in the Inr element, which encompasses the transcriptional start site at nt -99, resulted in a substantial reduction in the human FSH-R promoter/enhancer activity. Overexpression of upstream stimulating factor-1 (USF1) suppresses the activity of the human FSH-R promoter/enhancer via Inr and E-box elements. Upstream stimulating factor-2 (USF2) decreases FSH-R promoter/enhancer activity by acting on E-box 3. The results indicate that E-box 3 and the Inr element are important elements of the human FSH-R promoter/ enhancer. USF family members inhibit FSH-R gene activity by acting via these elements. USF1 and USF2 suppress human FSH-R promoter/enhancer activity by acting on E-box 3. USF1 also decreases activity by interacting with the Inr element.

State of the art in in-vitro oocyte maturation

PURPOSE OF REVIEW

The recovery of immature oocytes followed by in-vitro maturation (IVM) and in-vitro fertilization is an attractive alternative to conventional in-vitro fertilization treatment in which controlled ovarian stimulation with gonadotropins is used to increase the number of available oocytes and embryos. Significant progress has been made to improve pregnancy and implantation rates from in-vitro matured oocytes. This review summarizes current knowledge and achievements in human oocyte in-vitro maturation for clinical application, and will highlight recent advances reported in in-vitro maturation treatment.

RECENT FINDINGS

It has been demonstrated that priming of ovarian immature oocytes with follicle-stimulating hormone or human chorionic gonadotropin prior to immature oocyte retrieval improves oocyte maturation rates and embryo quality as well as pregnancy rates in infertile women with polycystic ovaries or polycystic ovary syndrome. The size of follicles may be important for the subsequent embryonic development, but the developmental competence of oocytes derived from the small antral follicles is not adversely affected by the presence of a dominant follicle. However oocyte maturation in vitro is profoundly affected by culture conditions. Currently more than 300 healthy infants have been born following immature oocyte retrieval and in-vitro maturation. In general, the clinical pregnancy and implantation rates have reached 30-35% and 10-15% respectively in infertile women with polycystic ovaries or polycystic ovary syndrome.

SUMMARY

In-vitro maturation treatment can now be offered as a successful option to infertile women with polycystic ovaries or polycystic ovary syndrome. It is possible to combine natural cycle in-vitro fertilization with immature oocyte retrieval followed by in-vitro maturation, and thus offer women with various causes of infertility reasonable pregnancy and implantation rates without recourse to ovarian stimulation. Further research remains to be done to address the mechanism of oocyte maturation in order to refine culture conditions and improve the implantation rate of oocytes matured in vitro.

In-vitro maturation of human oocytes

Immature human oocytes can be matured and fertilized in vitro. However, subsequent embryonic development is different when the immature oocytes are retrieved in different situations. Exposure to the LH surge in vivo may be important for the oocytes to acquire the competence for maturation and subsequent embryonic development. The size of the follicles may also be an important feature for subsequent embryonic development. However, the developmental competence of oocytes derived from small antral follicles does not seem to be adversely affected by the presence of a dominant follicle. Oocyte maturation in vitro is profoundly affected by culture conditions. Gonadotrophins are required for oocyte maturation in vivo, but any requirement in vitro is still unclear. Recent clinical results from in-vitro matured (IVM) human oocytes are promising, although further research remains to be done in order to address the mechanisms of oocyte maturation and to improve culture conditions and also the implantation rate of embryos generated from IVM oocytes.