Human Follicle Development Research Articles

Comprehensive Review of In Vitro Human Follicle Development for Fertility Restoration: Recent Achievements, Current Challenges, and Future Optimization Strategies.

Ovarian tissue cryopreservation (OTC) and subsequent transplantation (OTT) is a fertility preservation technique widely offered to prepubertal girls and young fertile women who need to undergo oncological treatment but are at a high risk of infertility. However, OTT is not considered safe in patients with certain diseases like leukemia, Burkitt's lymphoma, and ovarian cancer because of the associated risk of malignant cell reintroduction. In vitro follicle development has therefore emerged as a promising means of obtaining mature metaphase II (MII) oocytes from the primordial follicle (PMF) pool contained within cryopreserved ovarian tissue, without the need for transplantation. Despite its significant potential, this novel approach remains highly challenging, as it requires replication of the intricate process of intraovarian folliculogenesis. Recent advances in multi-step in vitro culture (IVC) systems, tailored to the specific needs of each follicle stage, have demonstrated the feasibility of generating mature oocytes (MII) from early-stage human follicles. While significant progress has been made, there is still room for improvement in terms of efficiency and productivity, and a long way to go before this IVC approach can be implemented in a clinical setting. This comprehensive review outlines the most significant improvements in recent years, current limitations, and future optimization strategies.

The role of pituitary gonadotropins and intraovarian regulators in follicle development: A mini-review.

BackgroundThe process of follicle development is tightly regulated by pituitary gonadotropins (follicle‐stimulating hormone [FSH] and luteinizing hormone [LH]) and intraovarian regulators (eg, steroids, growth factors, and cytokines).MethodsThis review outlines recent findings on the mechanisms of human follicle development, based on the research on animal models such as mice, rats, cows, and sheep.Main findingsPhosphatidylinositol 3‐kinase/protein kinase B signaling pathway and anti‐Müllerian hormone are involved in primordial follicle activation during the gonadotropin‐independent phase. The intraovarian regulators, such as androgen, insulin‐like growth factor system, activin, oocyte‐derived factors (growth differentiation factor‐9 and bone morphogenetic protein 15), and gap junction membrane channel protein (connexin), play a central role in the acquisition of FSH dependence in preantral follicles during the gonadotropin‐responsive phase. Antral follicle development can be divided into FSH‐dependent growth and LH‐dependent maturation. The indispensable tetralogy for follicle selection and final maturation of antral follicles involves (a) acquisition of LH dependence, (b) greater capacity for E2 production, (c) activation of the IGF system, and (d) an antiapoptotic follicular microenvironment.ConclusionWe reproductive endocrinologists should accumulate further knowledge from animal model studies to develop methods that promote early folliculogenesis and connect to subsequent gonadotropin therapy in infertile women.

In vivo and in vitro activation of dormant primordial follicles by EGF treatment in mouse and human.

In the mammalian ovaries, dormant primordial follicles represent the reproductive reserve of individual females. Recently, stimulating the activation of primordial follicles in vitro has been practiced, making the utilization of those dormant follicles to treat female infertility possible. However, there are still lacks of effective upstream molecule and strategy to elevate follicle activation in vivo. In the current study, we revealed that growth factor EGF improved a transiently primordial follicle activation in mice by elevating the CDC42‐PI3K signaling activity, and EGF treatment also improved the activation and development of human follicles in ovarian cortical pieces. Using a liquid‐solid phase transition bio‐gel as a carrier, an efficient in vivo activation system was established by ovarian topical EGF administration to living mice. We found that EGF treatment led to an increase of primordial follicle activation in short time but had no effect on long‐term fertility in females. By establishing an inducible premature ovarian insufficiency (POI) mouse model through selectively ablating growing follicles in Zp3‐Cre;iDTR mice, we further revealed that our in vivo EGF treatment system improved primordial follicle activation and ovulation of POI ovaries significantly. Taken together, our results revealed that in situ ovarian EGF administration could improve the activation of primordial follicles in living animals, and manipulating activation and development of primordial follicles in vivo might be an efficient approach to improve reproductive health in women.

Transcriptome Analysis of Long Non-coding RNAs and Genes Encoding Paraspeckle Proteins During Human Ovarian Follicle Development.

Emerging evidence indicated that many long non-coding (lnc)RNAs function in multiple biological processes and dysregulation of their expression can cause diseases. Most regulatory lncRNAs interact with biological macromolecules such as DNA, RNA, and protein. LncRNAs regulate gene expression through epigenetic modification, transcription, and posttranscription, through DNA methylation, histone modification, and chromatin remodeling. Interestingly, differential lncRNA expression profiles in human oocytes and cumulus cells was recently assessed, however, lncRNAs in human follicle development has not previously been described. In this study, transcriptome dynamics in human primordial, primary and small antral follicles were interrogated and revealed information of lncRNA genes. It is known that some lncRNAs form a complex with paraspeckle proteins and therefore, we extended our transcriptional analysis to include genes encoding paraspeckle proteins. Primordial, primary follicles and small antral follicles was isolated using laser capture micro-dissection from ovarian tissue donated by three women having ovarian tissue cryopreserved before chemotherapy. After RN sequencing, a bioinformatic class comparison was performed and primordial, primary and small antral follicles were found to express several lncRNA and genes encoding paraspeckle proteins. Of particular interest, we detected the lncRNAs XIST, NEAT1, NEAT2 (MALAT1), and GAS5. Moreover, we noted a high expression of FUS, TAF15, and EWS components of the paraspeckles, proteins that belong to the FET (previously TET) family of RNA-binding proteins and are implicated in central cellular processes such as regulation of gene expression, maintenance of genomic integrity, and mRNA/microRNA processing. We also interrogated the intra-ovarian localization of the FUS, TAF15, and EWS proteins using immunofluorescence. The presence and the dynamics of genes that encode lncRNA and paraspeckle proteins may suggest that these may mediate functions in the cyclic recruitment and differentiation of human follicles and could participate in biological processes known to be associated with lncRNAs and paraspeckle proteins, such as gene expression control, scaffold formation and epigenetic control through human follicle development. This comprehensive transcriptome analysis of lncRNAs and genes encoding paraspeckle proteins expressed in human follicles could potentially provide biomarkers of oocyte quality for the development of non-invasive tests to identify embryos with high developmental potential.

Metaphase II oocytes from human unilaminar follicles grown in a multi-step culture system.

Can complete oocyte development be achieved from human ovarian tissue containing primordial/unilaminar follicles and grown in vitro in a multi-step culture to meiotic maturation demonstrated by the formation of polar bodies and a Metaphase II spindle? Development of human oocytes from primordial/unilaminar stages to resumption of meiosis (Metaphase II) and emission of a polar body was achieved within a serum free multi-step culture system. Complete development of oocytes in vitro has been achieved in mouse, where in vitro grown (IVG) oocytes from primordial follicles have resulted in the production of live offspring. Human oocytes have been grown in vitro from the secondary/multi-laminar stage to obtain fully grown oocytes capable of meiotic maturation. However, there are no reports of a culture system supporting complete growth from the earliest stages of human follicle development through to Metaphase II. Ovarian cortical biopsies were obtained with informed consent from women undergoing elective caesarean section (mean age: 30.7 ± 1.7; range: 25-39 years, n = 10). Laboratory setting. Ovarian biopsies were dissected into thin strips, and after removal of growing follicles were cultured in serum free medium for 8 days (Step 1). At the end of this period secondary/multi-laminar follicles were dissected from the strips and intact follicles 100-150 μm in diameter were selected for further culture. Isolated follicles were cultured individually in serum free medium in the presence of 100 ng/ml of human recombinant Activin A (Step 2). Individual follicles were monitored and after 8 days, cumulus oocyte complexes (COCs) were retrieved by gentle pressure on the cultured follicles. Complexes with complete cumulus and adherent mural granulosa cells were selected and cultured in the presence of Activin A and FSH on membranes for a further 4 days (Step 3). At the end of Step 3, complexes containing oocytes >100 μm diameter were selected for IVM in SAGE medium (Step 4) then fixed for analysis. Pieces of human ovarian cortex cultured in serum free medium for 8 days (Step 1) supported early follicle growth and 87 secondary follicles of diameter 120 ± 6 μm (mean ± SEM) could be dissected for further culture. After a further 8 days, 54 of the 87 follicles had reached the antral stage of development. COCs were retrieved by gentle pressure from the cultured follicles and those with adherent mural granulosa cells (n = 48) were selected and cultured for a further 4 days (Step 3). At the end of Step 3, 32 complexes contained oocytes >100 μm diameter were selected for IVM (Step 4). Nine of these complexes contained polar bodies within 24 h and all polar bodies were abnormally large. Confocal immuno-histochemical analysis showed the presence of a Metaphase II spindle confirming that these IVG oocytes had resumed meiosis but their developmental potential is unknown. This is a small number of samples but provides proof of concept that complete development of human oocytes can occur in vitro. Further optimization with morphological evaluation and fertilization potential of IVG oocytes is required to determine whether they are normal. The ability to develop human oocytes from the earliest follicular stages in vitro through to maturation and fertilization would benefit fertility preservation practice. Funded by MRC Grants (G0901839 and MR/L00299X/1). No competing interests.

The effect of ovarian reserve and receptor signalling on granulosa cell apoptosis during human follicle development.

The poor oocyte quality in older women has previously been linked to the depletion of the ovarian reserve of primordial follicles and an increase in granulosal apoptosis. Granulosa cells were collected from 198 follicles and individually analysed by flow cytometry. In the young IVF patients, the level of apoptosis was inversely proportional to the expression of bone morphogenetic protein (BMPR1B) and follicle stimulating hormone (FSH) receptors. Conversely, in the older patients this relationship became dysregulated. In the older patients, at the time of preovulatory maturation, the reduced apoptosis reflects the poor mitogenic growth turnover rate of healthy follicles rather than the death rate in an atretic follicle. Restoring an optimum receptor density and down-regulation of receptors may improve oocyte quality and the pregnancy rate in older women.

Maternally Contributed Folate Receptor 1 Is Expressed in Ovarian Follicles and Contributes to Preimplantation Development.

Folates have been shown to play a crucial role for proper development of the embryo as folate deficiency has been associated with reduced developmental capacity such as increased risk of fetal neural tube defects and spontanous abortion. Transcripts encoding the reduced folate carrier RFC1 (SLC19A1 protein) and the high-affinity folate receptor FOLR1 are expressed in oocytes and preimplantation embryos, respectively. In this study, we observed maternally contributed FOLR1 protein during mouse and human ovarian follicle development, and 2-cell mouse embryos. In mice, FOLR1 was highly enriched in oocytes from primary, secondary and tertiary follicles, and in the surrounding granulosa cells. Interestingly, during human follicle development, we noted a high and specific presence of FOLR1 in oocytes from primary and intermediate follicles, but not in the granulosa cells. The distribution of FOLR1 in follicles was noted as membrane-enriched but also seen in the cytoplasm in oocytes and granulosa cells. In 2-cell embryos, FOLR1-eGFP fusion protein was detected as cytoplasmic and membrane-associated dense structures, resembling the distribution pattern observed in ovarian follicle development. Knock-down of Folr1 mRNA function was accomplished by microinjection of short interference (si)RNA targeting Folr1, into mouse pronuclear zygotes. This revealed a reduced capacity of Folr1 siRNA-treated embryos to develop to blastocyst compared to the siRNA-scrambled control group, indicating that maternally contributed protein and zygotic transcripts sustain embryonic development combined. In summary, maternally contributed FOLR1 protein appears to maintain ovarian functions, and contribute to preimplantation development combined with embryonically synthesized FOLR1.

Progestin and AdipoQ Receptor 7, Progesterone Membrane Receptor Component 1 (PGRMC1), and PGRMC2 and Their Role in Regulating Progesterone's Ability to Suppress Human Granulosa/Luteal Cells from Entering into the Cell Cycle.

The present studies were designed to determine the role of progesterone receptor membrane component 1 (PGRMC1), PGRMC2, progestin and adipoQ receptor 7 (PAQR7), and progesterone receptor (PGR) in mediating the antimitotic action of progesterone (P4) in human granulosa/luteal cells. For these studies granulosa/luteal cells of 10 women undergoing controlled ovarian hyperstimulation were isolated, maintained in culture, and depleted of PGRMC1, PGRMC2, PAQR7, or PGR by siRNA treatment. The rate of entry into the cell cycle was assessed using the FUCCI cell cycle sensor to determine the percentage of cells in the G1/S stage of the cell cycle. PGRMC1, PGRMC2, PAQR7, and PGR mRNA levels were assessed by real-time PCR and their interactions monitored by in situ proximity ligation assays (PLAs). These studies revealed that PGRMC1, PGRMC2, PAQR7, and PGR were expressed by granulosa/luteal cells from all patients, with PGRMC1 mRNA being most abundant, followed by PAQR7, PGRMC2, and PGR. However, their mRNA levels showed considerable patient variation. P4's ability to suppress entry into the cell cycle was dependent on PGRMC1, PGRMC2, and PAQR7 but not PGR. Moreover, PLAs indicated that PGRMC1, PGRMC2, and PAQR7 formed a complex within the cytoplasm. Based on these studies, it is proposed that these three P4 mediators form a complex within the cytoplasm that is required for P4's action. Moreover, P4's ability to regulate human follicle development may be dependent in part on the expression levels of each of these P4 mediators.

Alginate encapsulation supports the growth and differentiation of human primordial follicles within ovarian cortical tissue.

In vitro follicle growth (IVFG) is an investigational fertility preservation technique in which immature follicles are grown in culture to produce mature eggs that can ultimately be fertilized. Although progress has been made in growing primate primary and secondary follicles in vitro, it has been a relatively greater challenge to isolate and culture primordial follicles. The purpose of this study was to develop methods to grow human primordial follicles in vitro using alginate hydrogels. We obtained human ovarian tissue for research purposes through the National Physicians Cooperative from nationwide sites and used it to test two methods for culturing primordial follicles. First, primordial follicles were isolated from the ovarian cortex and encapsulated in alginate hydrogels. Second, 1mm × 1mm pieces of 500μm-thick human ovarian cortex containing primordial follicles were encapsulated in alginate hydrogels, and survival and follicle development within the tissue was assessed for up to 6weeks. We found that human ovarian tissue could be kept at 4°C for up to 24h while still maintaining follicle viability. Primordial follicles isolated from ovarian tissue did not survive culture. However, encapsulation and culture of ovarian cortical pieces supported the survival, differentiation, and growth of primordial and primary follicles. Within several weeks of culture, many of the ovarian tissue pieces had formed a defined surface epithelium and contained growing preantral and antral follicles. The early stages of in vitro human follicle development require the support of the native ovarian cortex.

Comparative Gene Expression Profiling in Human Cumulus Cells according to Ovarian Gonadotropin Treatments

In in vitro fertilization cycles, both HP-hMG and rFSH gonadotropin treatments are widely used to control human follicle development. The objectives of this study are (i) to characterize and compare gene expression profiles in cumulus cells (CCs) of periovulatory follicles obtained from patients stimulated with HP-hMG or rFSH in a GnRH antagonist cycle and (ii) to examine their relationship with in vitro embryo development, using Human Genome U133 Plus 2.0 microarrays. Genes that were upregulated in HP-hMG-treated CCs are involved in lipid metabolism (GM2A) and cell-to-cell interactions (GJA5). Conversely, genes upregulated in rFSH-treated CCs are implicated in cell assembly and organization (COL1A1 and COL3A1). Interestingly, some genes specific to each gonadotropin treatment (NPY1R and GM2A for HP-hMG; GREM1 and OSBPL6 for rFSH) were associated with day 3 embryo quality and blastocyst grade at day 5, while others (STC2 and PTX3) were related to in vitro embryo quality in both gonadotropin treatments. These genes may prove valuable as biomarkers of in vitro embryo quality.

In vitro grown human ovarian follicles from cancer patients support oocyte growth

Young female adult and adolescent cancer patients facing life-preserving but fertility-threatening chemo- or radiation-therapy are increasingly seeking options to protect their reproductive potential. Ovarian tissue cryopreservation with transplantation is a promising technique to safeguard fertility in cancer patients. However, this method may risk re-introduction of the original cancer to the survivor of the disease. Thus, developing a method for in vitro growth of immature follicles may provide a method for fertility restoration in the future. Human secondary follicles were isolated from ovarian tissues obtained from cancer patients and grown in vitro within a bio-engineered culture system for 30 days. Human ovarian follicles became steroidogenically active, and developed from the early secondary to antral stage in vitro. The follicles contained healthy, growing oocytes that were connected by transzonal projections between the somatic cells and oocyte. Our data support the notion that human follicle development can be achieved in vitro in a bio-engineered culture system. More studies are required to investigate whether the fully sized oocytes obtained from in vitro grown follicle are competent to resume meiosis and be fertilized.

Encapsulated Three-Dimensional Culture Supports Development of Nonhuman Primate Secondary Follicles1

In vitro ovarian follicle cultures may provide fertility-preserving options to women facing premature infertility due to cancer therapies. An encapsulated three-dimensional (3-D) culture system utilizing biomaterials to maintain cell-cell communication and support follicle development to produce a mature oocyte has been developed for the mouse. We tested whether this encapsulated 3-D system would also support development of nonhuman primate preantral follicles, for which in vitro growth has not been reported. Three questions were investigated: Does the cycle stage at which the follicles are isolated affect follicle development? Does the rigidity of the hydrogel influence follicle survival and growth? Do follicles require luteinizing hormone (LH), in addition to follicle-stimulating hormone (FSH), for steroidogenesis? Secondary follicles were isolated from adult rhesus monkeys, encapsulated within alginate hydrogels, and cultured individually for </=30 days. Follicles isolated from the follicular phase of the menstrual cycle had a higher survival rate (P < 0.05) than those isolated from the luteal phase; however, this difference may also be attributed to differing sizes of follicles isolated during the different stages. Follicles survived and grew in two hydrogel conditions (0.5% and 0.25% alginate). Follicle diameters increased to a greater extent (P < 0.05) in the presence of FSH alone than in FSH plus LH. Regardless of gonadotropin treatment, follicles produced estradiol, androstenedione, and progesterone by 14-30 days in vitro. Thus, an alginate hydrogel maintains the 3-D structure of individual secondary macaque follicles, permits follicle growth, and supports steroidogenesis for </=30 days in vitro. This study documents the first use of the alginate system to maintain primate tissue architecture, and findings suggest that encapsulated 3-D culture will be successful in supporting the in vitro development of human follicles.

Identification and Functional Analysis of a New WNT4 Gene Mutation among 28 Adolescent Girls with Primary Amenorrhea and Müllerian Duct Abnormalities: A French Collaborative Study

Müllerian duct development depends on gene and hormone interactions. Female Wnt4-knockout mice lack müllerian ducts and are virilized due to the inappropriate expression of the enzymes required for androgen production (normally repressed in female ovary). The WNT4 mutation was recently reported to be associated with failure of müllerian duct formation and virilization in two 46, XX women. This collaborative work was designed to determine whether the WNT4 mutation could be identified in a group of adolescent girls with Mayer-Rokitansky-Küster-Hauser syndrome. We analyzed 28 DNA samples from adolescent girls with primary amenorrhea and failure of müllerian duct formation by direct sequencing and identified a new L12P mutation within exon 1 of the WNT4 gene. The substitution of leucine by proline is crucial for the conformation of the expressed protein. This amino acid substitution is unlikely to be a polymorphism because it was not found in 100 DNAs from control subjects. Functional analysis revealed that the mutation induces significantly increased expression of the enzymes involved in androgen biosynthesis (3beta-hydroxysteroid dehydrogenase and 17alpha-hydroxylase). It is interesting to note that the adolescent carrying the mutation was referred to our clinic for primary amenorrhea and hyperandrogenism (severe acne and plasma testosterone: 1.8 vs. 1.2 nmol/liter in controls). She also presented with uterine hypoplasia and follicle depletion. We suggest that in adolescent girls with primary amenorrhea, müllerian duct abnormalities, and hyperandrogenism, a WNT4 mutation should be sought. Moreover, our data confirm that WNT4 is involved in the regulation of müllerian duct development and ovarian androgen biosynthesis. WNT4 may also contribute to human follicle development and/or maintenance.

Implications of Polycystic Ovary Syndrome on Oocyte Development

Human follicle development requires the recruitment of primordial follicles into a cohort of growing follicles from which one follicle is selected to ovulate a mature oocyte. During this developmental process, complex endocrine and intraovarian paracrine signals create a changing intrafollicular hormonal milieu. With this microenvironment, appropriate cumulus cell-oocyte signaling governs oocyte developmental competence, defined as the ability of the oocyte to complete meiosis and undergo fertilization, embryogenesis, and term development. Many of these mechanisms are perturbed in polycystic ovary syndrome (PCOS), a heterogeneous syndrome characterized by ovarian hyperandrogenism, hyperinsulinemia from insulin resistance, and reduced fecundity. In addition to these endocrinopathies, PCOS also is characterized by paracrine dysregulation of follicle development by intraovarian proteins of the transforming growth factor-beta family. Consequently, PCOS patients undergoing ovarian stimulation for in vitro fertilization are at increased risks of impaired oocyte developmental competence, implantation failure, and pregnancy loss. Recent data demonstrate links between endocrine/paracrine factors and oocyte gene expression in PCOS and suggest that new clinical strategies to optimize developmental competence of PCOS oocytes should target correction of the entire follicle growth and oocyte development process.

High oxygen atmosphere improves human follicle development in organ cultures of ovarian cortical tissues in vitro

Obtaining mature human follicles from cultured ovarian tissue may be beneficial for clinical use for women who wish to preserve fertile competence. However, the methodology of culture such as culture condition and gas atmosphere has not been well established in humans. Therefore, we investigated the effect of oxygen concentration in organ culture in order to establish an ovarian tissue culture method. Ovarian tissue was obtained from 26-35-year-old women undergoing removal of a benign tumor (n = 12) or caesarean section (n = 16). The ovarian cortical tissues were cultured on a cell culture insert for 15 days under high (100%) and low (air, 20%) oxygen concentrations and then inspected for follicle development with light and electron microscopy. Estradiol and progesterone concentrations in the medium during culture were measured. The ultrastructure and the function of hormone secretion in the cultured tissues were well preserved after organ culture. The follicles developing under high oxygen were larger and more matured than those developing under low oxygen (P < 0.05). Human ovarian tissues can be cultured for 15 days under high oxygen concentration with the organ culture system used here. This technique could make it possible to utilize ovarian tissue for preservation of reproductive competence in cancer patients.

O-63: Angiogenesis factors in human ovarian follicular development: The presence of vascular endothelial growth factor and placental growth factor in follicular fluid

It has been demonstrated that angiogenesis plays an important role in normal cyclical ovarian function. In particular, follicular growth is dependent upon the proliferation of new capillary vessels, and, it has been proposed that the process of selection of a dominant follicle is likely to be associated with angiogenesis. Vascular endothelial growth factor (VEGF) and its homolog the placental growth factor (PlGF) are vascular cell-specific mitogen factors with a key function in angiogenesis. Their role in human follicular growth and oocyte maturation however, is less well-understood and the presence of PlGF in human follicles has not been previously demonstrated. This study sought to determine the content of both VEGF and PlGF within the follicular fluid (FF) of large and small follicles of women undergoing in vitro fertilization (IVF) and to relate their content to patient age A prospective laboratory-based study at an academic center. Women between the ages of 25 - 43 years old undergoing IVF were enrolled under IRB approval during the time of oocyte retrieval. Follicles were measured by transvaginal ultrasound in 2 dimensions prior to aspiration. FF from lead (>14mm) and small (< 12mm) follicles was collected by transvaginal aspiration. Cellular components and immunoglobulins were removed by centrifugation and protein A/G chromatography. VEGF and PlGF concentration in FF were then analyzed via enzyme-linked immunosorbent assay (ELISA) on lead and small follicles from young (</= 34 years) and old (>/= 40 years) samples and confirmed by western blot with specific antibodies. Results were analyzed with students’t test and statistical significance was set at a p value of < 0.05. The results of the Western Blot analysis showed the presence of both VEGF and PlGF within the FF. The mean concentration of PlGF in lead follicles was 42.41 pg/ml and the mean concentration in small follicles was 55.91 pg/ml (p= 0.10). The mean concentration of VEGF in lead follicles was 5,745.76 pg/ml whereas the mean concentration in small follicles was 3,485.70 pg/ml (p<0.01). The concentration of VEGF and PlGF did not vary with respect to age. This study demonstrated a significantly increased concentration of VEGF in the follicular fluid of lead follicles compared with smaller follicles irrespective of age, lending proof to the idea that angiogenesis is an important part of lead human follicle development. The trend of our results for PlGF supports findings suggesting that PlGF may act as a natural VEGF antagonist. Additionally, our western blot and ELISA results are the first demonstration of the presence of PlGF in human FF. Overall, this study demonstrates that angiogenesis factors are important in follicular development in women undergoing IVF.

Growth differentiation factor-9 (GDF-9) mRNA expression in human granulosa cells: relation to IVF outcome.

Objective: There is accumulating evidence that mammalian oocytes secrete factors that regulate the development of the surrounding granulosa cells in ovarian follicles. Several of these paracrine-signaling factors are coexpressed in all stages of follicular development and in the oocyte. GDF-9, a member of the transforming growth factor β (TGF-β) superfamily, was shown recently to be essential in early follicular development. GDF-9 deficient mice display an arrest of follicle growth at the primary follicle stage. Little information is available regarding the granulosa cell GDF-9 expression and regulation of folliculogenesis after ovulation induction for IVF. The aim of this study was to investigate the role of GDF-9 in human follicle development by quantifying intrafollicular mRNA expression and exploring the relationship of its expression with the efficacy of ovulation induction and IVF outcome.

Development of human primordial follicles to antral stages in SCID/hpg mice stimulated with follicle stimulating hormone.

In contrast to the many detailed studies of Graafian follicles, the biology of small follicles in the human ovary is poorly understood and the trigger for follicular growth initiation remains unknown. No practical model exists to study preantral follicle growth in the human because of their slow growth rate and lack of an effective culture system. We therefore tested ovarian xenografts as a new strategy to study the early stages of ovarian follicular growth in vivo. Mice homozygous for severe combined immunodeficiency (SCID) and hypogonadism (hpg) received human ovarian xenografts under their kidney capsules. Follicle growth was assessed by morphology and proliferating cell nuclear antigen (PCNA) immunostaining. The grafts were recovered after 11 (short-term) and 17 weeks (long-term), and serially sectioned. During the last 6 weeks of long-term grafting, mice were randomized to receive either placebo or 1 IU of purified follicle stimulating hormone (FSH) s.c. on alternating days. After 11 weeks of grafting, the most advanced follicles had a maximum of two granulosa cell layers. In the absence of FSH administration, follicles did not progress beyond the two-layer stage even after 17 weeks of grafting, and the oestradiol levels remained undetectable. In the FSH-treated long-term grafts, follicles had grown to antral stages and resulted in oestradiol levels as high as 2070 pmol/l. Growth initiation indices did not differ between control and FSH-treated grafts. This study demonstrates that follicles can survive and grow in human ovarian tissue grafted under the renal capsules of immunodeficient mice for at least 17 weeks, and indicate that xenograft models are potentially useful for studying human follicle development. Using this physiological model, we showed that FSH is required for follicle growth beyond the two-layer stage, although growth initiation is independent of gonadotrophin stimulation.

Growth hormone enhances estradiol production follicle-stimulating hormone-induced in the early stage of the follicular maturation

To investigate the ability of GH to increase the steroidogenic response of the ovary to FSH in the early stage of human follicle development in vivo. Ovarian sensitivity to FSH and/or GH during the early follicular phase of the human menstrual cycle was evaluated in a prospective study. Normal human volunteers in the Department of Obstetrics and Gynecology, Università Cattolica Sacro Cuore. Twenty-four normal patients with normo-ovulatory cycles and tubal factor infertility. Pure urinary FSH (75 IU) or saline were injected IV in the early follicular phase with or without a pretreatment with human GH (0.1 IU/kg IM for 3 days). Plasma levels of LH, FSH, E2, and T in samples collected for a period of 26 hours after saline or FSH IV injection. Follicle-stimulating hormone injection increased E2 and E2:T stimulated area under the curve (AUC) with respect to saline administration. Moreover, the E2 secretion was increased significantly in the group treated with GH plus FSH as compared with that found in the group receiving FSH alone. Growth hormone itself was unable to increase any steroidogenic response by ovary in terms of both E2 and E2:T AUC values. The results of present study demonstrate in vivo a synergistic effect of GH on the FSH-induced follicular steroidogenesis, suggesting a potential relevance of GH in the reproductive biology.

The Role of Luteinizing Hormone in Human Follicle Development and Oocyte Fertility

Balasch, Juan; Miro, Fernando; Burzaco, Ignacio; Casamitjana, Roser; Civico, Salvadora; Ballesca, Jose L.; Puerto, Bienvenido; Vanrell, Juan A. Author Information