Follicular fluid and supernatant from cultured cumulus-granulosa cells improve in vitro maturation in patients with polycystic ovarian syndrome

HDAC1-Mediated lncRNA Stimulatory Factor of Follicular Development to Inhibit the Apoptosis of Granulosa Cells and Regulate Sexual Maturity through miR-202-3p-COX1 Axis

Abnormal sexual maturity exhibits significant detrimental effects on adult health outcomes, and previous studies have indicated that targeting histone acetylation might serve as a potential therapeutic approach to regulate sexual maturity. However, the mechanisms that account for it remain to be further elucidated. Using the mouse model, we showed that Trichostatin A (TSA), a histone deacetylase (HDAC) inhibitor, downregulated the protein level of Hdac1 in ovaries to promote the apoptosis of granulosa cells (GCs), and thus arrested follicular development and delayed sexual maturity. Using porcine GCs as a cell model, a novel sexual maturity-associated lncRNA, which was named as the stimulatory factor of follicular development (SFFD), transcribed from mitochondrion and mediated by HDAC1, was identified using RNA sequencing. Mechanistically, HDAC1 knockdown significantly reduced the H3K27ac level at the -953/-661 region of SFFD to epigenetically inhibit its transcription. SFFD knockdown released miR-202-3p to reduce the expression of cyclooxygenase 1 (COX1), an essential rate-limited enzyme involved in prostaglandin synthesis. This reduction inhibited the proliferation and secretion of 17β-estradiol (E2) while promoting the apoptosis of GCs. Consequently, follicular development was arrested and sexual maturity was delayed. Taken together, HDAC1 knockdown-mediated SFFD downregulation promoted the apoptosis of GCs through the miR-202-3p-COX1 axis and lead to delayed sexual maturity. Our findings reveal a novel regulatory network modulated by HDAC1, and HDAC1-mediated SFFD may be a promising new therapeutic target to treat delayed sexual maturity.

Focusing on the accumulation of chromatin/chromosomes around nucleoli and optimizing the timing of ICSI to facilitate the rescue in vitro maturation of denuded GV stage oocytes

PURPOSE

This study aims to achieve the methodological improvement of rescue IVM by predicting germinal vesicle breakdown (GVBD) and optimizing the timing of ICSI.

METHODS

Time lapse analysis was performed retrospectively to evaluated the relationship between the presence of AC around the nucleoli and GVBD. To find the optimal timing of ICSI, the time from the initiation of the first polar body extrusion to ICSI were measured, and the rates of fertilization at each point were calculated.

RESULTS

The GVBD rate of GV stage oocytes with AC around the nucleoli was significantly higher than that of GV stage oocytes without AC. The GV stage oocytes required more time for nuclear maturation after polar body extrusion than MI oocytes, with GV stage oocytes taking 400-600 min from polar body extrusion to the optimal timing of ICSI, while the MI stage oocytes took 200-400 min. The GV stage oocytes resulted in the birth of healthy babies with the appropriate timing of ICSI.

CONCLUSION

It was found that GV stage oocytes with AC around nucleoli can initiate GVBD and reach the MII stage with a high rate, and that GV stage oocytes required more time than MI stage oocytes to reach the optimal timing of ICSI. Considering these factors, ART laboratories may employ immature GV stage oocytes in routine ART procedures rather than discarding them.

In vitro maturation of oocytes from stimulated IVF-ICSI cycles using autologous cumulus cell co-culture: A preliminary study

PURPOSE OF THE STUDY

In stimulated IVF-ICSI cycles, follicles at different stages of maturation can be aspirated during oocyte pickup. Nowadays, only mature oocytes (metaphase 2 stage) are used and immature oocytes (germinal vesicle and metaphase 1 stages), which are judged unfit for fertilization, are non-used at day 0. In our IVF center, the rate of immature oocytes recovered is around 25%. A significant number of this precious resource is therefore non-used every day in IVF laboratories. The objective of our study was to evaluate the competence of our in vitro maturation autologous coculture method on the maturation and developmental potential of immature oocytes obtained from stimulated IVF-ICSI cycles, in order to obtain additional embryos for the couple as a rescue system to increase the changes of cumulative pregnancy.

PATIENTS AND METHODS

This is a prospective study, carried out in the Reproductive Medicine and Biology Unit of the Amiens-Picardy University Hospital (France). It was included 14 couples, managed in IVF-ICSI in our center, from January to March 2020. Thirty-eight oocytes, identified as immature after cumulus-oocyte complexes (COC) stripping for ICSI, were placed in our in vitro maturation medium with the addition of autologous cumulus cells. Oocytes that had reached the metaphase II stage after a maximum of 36 hours of maturation were microinjected. The fertilization and embryonic development potential of the in vitro matured oocytes were compared to those of 148 in vivo matured "siblings" oocytes from the same oocyte retrieval, and then also compared to those of 127 in vivo matured oocytes from different patients (control group).

MAIN OUTCOME MEASURE(S)

Maturation rate, fertilization rate, early cleavage rate and developmental activity to blastulation rate.

SECOND OUTCOME MEASURE(S)

Embryo quality at cleavage and blastocyst stages, blastulation rate, and useful blastulation rate.

RESULTS

No significant difference was found in the main and secondary criteria of the study compared to the "siblings" in vivo matured oocytes from the same oocyte retrieval. However, a significant difference was obtained on the rate of early cleavage and useful blastulation when our cohort was compared to mature in vivo oocytes from different patients (control group).

CONCLUSION

This study has shown that after incubation in our in vitro maturation autologous cumulus cell co-culture with cumulus-oocyte cells, immature oocytes recovered during stimulated cycles can give rise to competent oocytes, i.e., capable of being fertilized, of cleaving, and of developing into embryos up to the blastocyst stage. Our study therefore seems to be in the direction of a favorable use of these immature oocytes obtained after stimulated IVF-ICSI cycles. The continuation of this study by including a larger number of oocytes is necessary in order to evaluate the real contribution of this technique in routine.

Intercellular communication in the cumulus-oocyte complex during folliculogenesis: A review

During folliculogenesis, the oocyte and surrounding cumulus cells form an ensemble called the cumulus-oocyte complex (COC). Due to their interdependence, research on the COC has been a hot issue in the past few decades. A growing body of literature has revealed that intercellular communication is critical in determining oocyte quality and ovulation. This review provides an update on the current knowledge of COC intercellular communication, morphology, and functions. Transzonal projections (TZPs) and gap junctions are the most described structures of the COC. They provide basic metabolic and nutrient support, and abundant molecules for signaling pathways and regulations. Oocyte-secreted factors (OSFs) such as growth differentiation factor 9 and bone morphogenetic protein 15 have been linked with follicular homeostasis, suggesting that the communications are bidirectional. Using advanced techniques, new evidence has highlighted the existence of other structures that participate in intercellular communication. Extracellular vesicles can carry transcripts and signaling molecules. Microvilli on the oocyte can induce the formation of TZPs and secrete OSFs. Cell membrane fusion between the oocyte and cumulus cells can lead to sharing of cytoplasm, in a way making the COC a true whole. These findings give us new insights into related reproductive diseases like polycystic ovary syndrome and primary ovarian insufficiency and how to improve the outcomes of assisted reproduction.

Cell therapy for the treatment of reproductive diseases and infertility: an overview from the mechanism to the clinic alongside diagnostic methods

Infertility is experienced by 8%-12% of adults in their reproductive period globally and has become a prevalent concern. Besides routine therapeutic methods, stem cells are rapidly being examined as viable alternative therapies in regenerative medicine and translational investigation. Remarkable progress has been made in understanding the biology and purpose of stem cells. The affected pluripotent stem cells (iPSCs) and mesenchymal stem cells (MSCs) are further studied for their possible use in reproductive medicine, particularly for infertility induced by premature ovarian insufficiency and azoospermia. Accordingly, this study discusses current developments in the use of some kinds of MSCs such as adipose-derived stem cells, bone marrow stromal cells, umbilical cord MSCs, and menstrual blood MSCs. These methods have been used to manage ovarian and uterine disorders, and each technique presents a novel method for the therapy of infertility.

Rescue IVM of Denuded GV- and MI-Stage Oocytes of Premenopausal Rats with Oncostatin M, Insulin-like Growth Factor I, and Growth Hormone

Immature oocytes are retrieved and matured through in vitro maturation (IVM). Maturation, fertilization rates, and embryo development via IVM are all lower than those found in vitro fertilization (IVF) cycles. We investigated the effects of oncostatin M (OSM), insulin-like growth factor-1 (IGF-I), and growth hormone (GH) in rescue IVM. A total of 111 germinal vesicle (GV) and 17 metaphase I (MI) oocytes were obtained after conventional IVF from 28 female Wistar albino rats. Denuded immature oocytes were cultured in maturation medium supplemented with OSM, IGF-1, or GH. The quantities of metaphase II (MII) oocytes matured from the GV stage were 17 of 30 (56.6%), 15 of 28 (53.5%), 10 of 30 (33.3%), and 7 of 23 (30.3%), in control, OSM, IGF-I, and GH groups, respectively. Maturation rates in control and OSM groups were higher than those in IGF-I and GH groups (p = 0.001). The quantities of MII oocytes matured from MI stage were 7 of 7 (100%), 4 of 4 (100%), 1 of 1 (100%), and 1 of 5 (20%) in control, OSM, IGF-I, and GH groups, respectively. Maturation rates from MI to MII stages in control, OSM, and IGF-I groups were higher than those in the GH group (p = 0.004). Acceptable maturation rates are observed with OSM in rat oocytes in rescue IVM.

Factors Influencing the In Vitro Maturation (IVM) of Human Oocyte

In vitro maturation (IVM) of oocytes is a promising assisted reproductive technology (ART) deemed as a simple and safe procedure. It is mainly used in patients with impaired oocyte maturation and in fertility preservation for women facing the risk of losing fertility. However, to date, it is still not widely used in clinical practice because of its underperformance. The influencing factors, such as biphasic IVM system, culture medium, and the supplementation, have a marked effect on the outcomes of oocyte IVM. However, the role of different culture media, supplements, and follicular priming regimens in oocyte IVM have yet to be fully clarified and deserve further investigation.

Effects of demethylase KDM4B on the biological characteristics and function of yak cumulus cells in vitro

The present study aims to investigate the expression and function of lysine-specific demethylase 4B (KDM4B) in yak cumulus cells (CCs) in order to reveal the mechanisms by which KDM4B regulates biological characteristics and function of CCs. The cellular location of KDM4B and the methylation pattern of H3K9 were detected using immunofluorescence (IF) staining in CCs. The mRNA expression levels of apoptosis-related genes (BCL-2, HAX1 and BAX) and genes related to the estrogen pathway (ESR2, CYP17 and 3B-HSD) were estimated by qRT-PCR after knockdown of KDM4B expression by siRNA in yak CCs. Then, a proliferation assay, Annexin V-FITC staining, and ELISA were utilized to explore the effects of KDM4B silencing on CCs proliferation, apoptosis, and estrogen (E₂) secretion, respectively. The results showed that KDM4B is located in the nuclei of yak CCs and is distributed in a dotted pattern. Knockdown KDM4B induced a decrease in cell proliferation, an increase in apoptotic rate and a reduction in the levels of E₂ secretion of CCs. Additionally, the methylation patterns of H3K9me2 and H3K9me3 were significantly increased in CCs transfected with KDM4B siRNA-1 (P < 0.05). The mRNA expression level of apoptosis promoting BAX genes was significantly upregulated, but 3B-HSD, ESR2 and anti-apoptotic HAX1 genes were significantly downregulated in transfected CCs (P < 0.05). Furthermore, the rate of embryos developing from the 2-cell stage to blastocysts was lower in the siRNA-1 transfection group than that of the control group (28.6 ± 2.9% vs 40.4 ± 2.4%, P < 0.05). In conclusion, our study indicates that KDM4B regulates the biological characteristics and physiological function of yak CCs mainly through changing the methylation patterns of H3K9 and related gene expression levels.

Developmental potential of immature human oocytes aspirated after controlled ovarian stimulation

PURPOSE

Intracytoplasmic sperm injection (ICSI) for initially immature oocytes that mature in vitro is controversial and practice varies widely. While it may increase the number of usable embryos, it may also be time-intensive and potentially low-yield. This study sought to elucidate which patients may benefit from ICSI of initially immature oocytes that matured in vitro.

METHODS

A retrospective study comparing fertilization, cleavage, blastulation, and embryo usage rates between sibling initially immature and mature oocytes that underwent ICSI between 2015 and 2019 was performed. Outcomes of initially immature oocytes were stratified by initial maturation stage, timing of progression to metaphase II (MII) in vitro, percentage of mature oocytes in the cycle, and female age.

RESULTS

Ten thousand eight hundred seventeen oocytes from 889 cycles were included. Of 3137 (29.0%) initially immature oocytes, 418 (13.3%) reached MII later on the day of retrieval (day 0) and 1493 (47.6%) on day 1. Overall, embryos originating from initially immature oocytes had lower cleavage and blastulation rates compared to those from initially mature oocytes (P<0.05, all groups). However, embryos from oocytes that matured later on day 0 comprised a unique subset that had clinically similar cleavage (75% vs 80%, RR 0.93, P=0.047) and blastulation rates (41% vs 50%, RR 0.81, P=0.024) compared to initially mature oocytes. Women with low percentages of mature oocytes in the cycle overall and women ≥40 in cleavage cycles derived the highest relative benefit from the use of immature oocytes.

CONCLUSION

ICSI of immature oocytes, particularly those that mature later on the day of retrieval, may improve numbers of usable embryos. This study supports routine reassessment of immature oocytes for progression to MII and ICSI on day 0. An additional reassessment on day 1 may also be of use in older women or those with low percentage of mature oocytes.

Therapeutic Role of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Female Reproductive Diseases

Reproductive disorders, including intrauterine adhesion (IUA), premature ovarian insufficiency (POI), and polycystic ovary syndrome (PCOS), are great threats to female reproduction. Recently, mesenchymal stem cells derived-extracellular vesicles (MSC-EVs) have presented their potentials to cure these diseases, not only for the propensity ability they stemmed from the parent cells, but also for the higher biology stability and lower immunogenicity, compared to MSCs. EVs are lipid bilayer complexes, functional as mediators by transferring multiple molecules to recipient cells, such as proteins, microRNAs, lipids, and cytokines. EVs appeared to have a therapeutic effect on the female reproductive disorder, such as repairing injured endometrium, suppressing fibrosis of endometrium, regulating immunity and anti-inflammatory, and repressing apoptosis of granulosa cells (GCs) in ovaries. Although the underlying mechanisms of MSC-EVs have reached a consensus, several theories have been proposed, including promoting angiogenesis, regulating immunity, and reducing oxidate stress levels. In the current study, we summarized the current knowledge of functions of MSC-EVs on IUA, POI, and PCOS. Given the great potentials of MSC-EVs on reproductive health, the critical issues discussed will guide new insights in this rapidly expanding field.

Human Granulosa Cells-Stemness Properties, Molecular Cross-Talk and Follicular Angiogenesis

The ovarian follicle is the basic functional unit of the ovary, comprising theca cells and granulosa cells (GCs). Two different types of GCs, mural GCs and cumulus cells (CCs), serve different functions during folliculogenesis. Mural GCs produce oestrogen during the follicular phase and progesterone after ovulation, while CCs surround the oocyte tightly and form the cumulus oophurus and corona radiata inner cell layer. CCs are also engaged in bi-directional metabolite exchange with the oocyte, as they form gap-junctions, which are crucial for both the oocyte’s proper maturation and GC proliferation. However, the function of both GCs and CCs is dependent on proper follicular angiogenesis. Aside from participating in complex molecular interplay with the oocyte, the ovarian follicular cells exhibit stem-like properties, characteristic of mesenchymal stem cells (MSCs). Both GCs and CCs remain under the influence of various miRNAs, and some of them may contribute to polycystic ovary syndrome (PCOS) or premature ovarian insufficiency (POI) occurrence. Considering increasing female fertility problems worldwide, it is of interest to develop new strategies enhancing assisted reproductive techniques. Therefore, it is important to carefully consider GCs as ovarian stem cells in terms of the cellular features and molecular pathways involved in their development and interactions as well as outline their possible application in translational medicine.

Endometrial injection of embryo culture supernatant for subfertile women in assisted reproduction

BACKGROUND

Despite substantial improvements in the success of assisted reproduction techniques (ART), live birth rates may remain consistently low, and practitioners may look for innovative treatments to improve the outcomes. The injection of embryo culture supernatant in the endometrial cavity can be undertaken at various time intervals before embryo transfer. It provides an altered endometrial environment through the secretion of factors considered to facilitate implantation. It is proposed that injection of the supernatant into the endometrial cavity prior to embryo transfer will stimulate the endometrium and provide better conditions for implantation to take place. An increased implantation rate would subsequently increase rates of clinical pregnancy and live birth, but current robust evidence on the efficacy of injected embryo culture supernatant is lacking.

OBJECTIVES

To evaluate the effectiveness and safety of endometrial injection of embryo culture supernatant before embryo transfer in women undergoing ART.

SEARCH METHODS

Our search strategies were designed with the help of the Cochrane Gynaecology and Fertility Group Information Specialist. We sought to identify all published and unpublished randomised controlled trials (RCTs) meeting inclusion criteria. Searches were performed on 2 December 2019. We searched the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL, MEDLINE, Embase, CINAHL, trials registries and grey literature. We made further searches in the UK National Institute for Health and Care Excellence (NICE) fertility assessment and treatment guidelines. We handsearched reference lists of relevant systematic reviews and RCTs, together with searches of PubMed and Google for any recent trials that have not yet been indexed in the major databases. We had no language or location restrictions.

SELECTION CRITERIA

We included RCTs testing the use of endometrial injection of embryo culture supernatant before embryo transfer during an ART cycle, compared with the non-use of this intervention, the use of placebo or the use of any other similar drug.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, extracted data from studies and attempted to contact the authors where data were missing. We pooled studies using a fixed-effect model. Our primary outcomes were live birth/ongoing pregnancy and miscarriage. We performed statistical analysis using Review Manager 5. We assessed evidence quality using GRADE methods.

MAIN RESULTS

We found five RCTs suitable for inclusion in the review (526 women analysed). We made two comparisons: embryo culture supernatant use versus standard care or no intervention; and embryo culture supernatant use versus culture medium. All studies were published as full-text articles. Data derived from the reports or through direct communication with investigators were available for the final meta-analysis performed. The GRADE evidence quality of studies ranged from very low-quality to moderate-quality. Factors reducing evidence quality included high risk of bias due to lack of blinding, unclear risk of publication bias and selective outcome reporting, serious inconsistency among study outcomes, and serious imprecision due to wide confidence intervals (CIs) and low numbers of events. Comparison 1. Endometrial injection of embryo culture supernatant before embryo transfer versus standard care or no intervention: One study reported live birth only and two reported the composite outcome live birth and ongoing pregnancy. We are uncertain whether endometrial injection of embryo culture supernatant before embryo transfer during an ART cycle improves live birth/ongoing pregnancy rates compared to no intervention (odds ratio (OR) 1.11, 95% CI 0.73 to 1.70; 3 RCTs; n = 340, I² = 84%; very low-quality evidence). Results suggest that if the chance of live birth/ongoing pregnancy following placebo or no treatment is assumed to be 42%, the chance following the endometrial injection of embryo culture supernatant before embryo transfer would vary between 22% and 81%. We are also uncertain whether the endometrial injection of embryo culture supernatant could decrease miscarriage rates, compared to no intervention (OR 0.89, 95% CI 0.44 to 1.78, 4 RCTs, n = 430, I² = 58%, very low-quality evidence). Results suggest that if the chance of miscarriage following placebo or no treatment is assumed to be 9%, the chance following injection of embryo culture supernatant would vary between 3% and 30%. Concerning the secondary outcomes, we are uncertain whether the injection of embryo culture supernatant prior to embryo transfer could increase clinical pregnancy rates (OR 1.13, 95% CI 0.80 to 1.61; 5 RCTs; n = 526, I² = 0%; very low-quality evidence), decrease ectopic pregnancy rates (OR 0.32, 95% CI 0.01 to 8.24; n = 250; 2 RCTs; I² = 41%; very low-quality evidence), decrease multiple pregnancy rates (OR 0.70, 95% CI 0.26 to 1.83; 2 RCTs; n = 150; I² = 63%; very low-quality evidence), or decrease preterm delivery rates (OR 0.63, 95% CI 0.17 to 2.42; 1 RCT; n = 90; I² = 0%; very low-quality evidence), compared to no intervention. Finally, there may have been little or no difference in foetal abnormality rates between the two groups (OR 3.10, 95% CI 0.12 to 79.23; 1 RCT; n = 60; I² = 0%; low-quality evidence). Comparison 2. Endometrial injection of embryo culture supernatant versus endometrial injection of culture medium before embryo transfer We are uncertain whether the use of embryo culture supernatant improves clinical pregnancy rates, compared to the use of culture medium (OR 1.09, 95% CI 0.48 to 2.46; n = 96; 1 RCT; very low-quality evidence). No study reported live birth/ongoing pregnancy, miscarriage, ectopic or multiple pregnancy, preterm delivery or foetal abnormalities.

AUTHORS' CONCLUSIONS

We are uncertain whether the addition of endometrial injection of embryo culture supernatant before embryo transfer as a routine method for the treatment of women undergoing ART can improve pregnancy outcomes. This conclusion is based on current available data from five RCTs, with evidence quality ranging from very low to moderate across studies. Further large well-designed RCTs reporting on live births and adverse clinical outcomes are still required to clarify the exact role of endometrial injection of embryo culture supernatant before embryo transfer.

Biological and physiological characteristics of human cumulus cells in adherent culture condition

Background

Cumulus cells, as oocyte nurse cells, provide a suitable microenvironment with growth factors and cellular interactions required for oocyte maturation. Thus, these cells may serve as a natural niche for in vitro studies of female germ cell development. Cumulus cells may help attain a better understanding of the causes of infertility in women and eventually improve the outcomes of cases that respond poorly to standard infertility treatment.

Objective

The aim of this study was to isolate, culture, and investigate the biological characteristics of human cumulus cells.

Materials and Methods

In this experimental study, cumulus cells were isolated, cultured, and characterized using reverse transcription-polymerase chain reaction analyses of specific genes including FOXL2, CYP19A1, FSHR, AMHR, and LHR. The presence of vimentin, a structural protein, was examined via immunofluorescent staining. Moreover, levels of anti-mullerian hormone (AMH) and progesterone secretion by cumulus cells were measured with ELISA after 2, 4, 12, 24, and 48 hr of culture.

Results

In adherent culture, human cumulus cells expressed specific genes and markers as well as secreted AMH and progesterone into the medium.

Conclusion

Cumulus cells secrete AMH and progesterone in an adherent culture and might be applicable for in vitro maturation (IVM) and in vitro gametogenesis (IVG) studies.

Luteinizing Hormone Action in Human Oocyte Maturation and Quality: Signaling Pathways, Regulation, and Clinical Impact

The ovarian follicle luteinizing hormone (LH) signaling molecules that regulate oocyte meiotic maturation have recently been identified. The LH signal reduces preovulatory follicle cyclic nucleotide levels which releases oocytes from the first meiotic arrest. In the ovarian follicle, the LH signal reduces cyclic nucleotide levels via the CNP/NPR2 system, the EGF/EGF receptor network, and follicle/oocyte gap junctions. In the oocyte, reduced cyclic nucleotide levels activate the maturation promoting factor (MPF). The activated MPF induces chromosome segregation and completion of the first and second meiotic divisions. The purpose of this paper is to present an overview of the current understanding of human LH signaling regulation of oocyte meiotic maturation by identifying and integrating the human studies on this topic. We found 89 human studies in the literature that identified 24 LH follicle/oocyte signaling proteins. These studies show that human oocyte meiotic maturation is regulated by the same proteins that regulate animal oocyte meiotic maturation. We also found that these LH signaling pathway molecules regulate human oocyte quality and subsequent embryo quality. Remarkably, in vitro maturation (IVM) prematuration culture (PMC) protocols that manipulate the LH signaling pathway improve human oocyte quality of cultured human oocytes. This knowledge has improved clinical human IVM efficiency which may become a routine alternative ART for some infertile patients.

Do the Cytoplast and Nuclear Material of Germinal Vesicle Oocyte Support Developmental Competence Upon Reconstruction with Embryonic/Somatic Nucleus

Maturation conditions and oocytes quality have substantial roles on developmental competence of unreconstructed or reconstructed oocytes. Cloning has been reported successfully with low efficiency through embryonic or somatic nuclear transfer into enucleated metaphase II oocytes. It has been suggested that introducing embryonic or somatic nucleus to cytoplast at earlier stage might improve reprogramming of the introduced nucleus. In addition, the synchronization between the donor nucleus and recipient cytoplasts might effect on reprogramming and further embryonic development. Therefore, the question arises; does the cytoplast of germinal vesicle (GV) oocyte containing nuclear sap improve developmental competence upon reconstruction with embryonic/somatic nucleus compared with MII cytoplast. It has been indicated that GV material is essential for remodeling of sperm or embryonic or somatic nucleus in GV oocyte cytoplast and their further embryonic developmental competence. GV cytoplasts could be obtained through micromanipulation. Different micromanipulation techniques of immature oocytes at different stages were adapted in addition to introducing donor nuclei at G0/G1, S and G2/M phase, and enucleolation technique as well. Upon micromanipulation, it could obtain GV cytoplasts; cumulus-free and without GV material, cumulus-complexes and without GV material, cumulus-free and with GV material, and cumulus-complexes and with GV material in addition to enucleolated GV oocytes. Therefore, this short review will address briefly the importance of maturation conditions, cumulus cells, oocyte quality, the techniques of enucleation GV oocyte, the cell cycle stage of the introduced donor cell, or nucleus for oocyte maturation and embryo development.

The Place of In Vitro Maturation in Assisted Reproductive Technology

In vitro maturation (IVM) is an assisted reproductive technology (ART) whereby immature cumulus-oocyte complexes are collected and matured in vitro, without need for controlled ovarian stimulation and ovulation triggering. Advantages of IVM over in vitro fertilization (IVF) include mild or no stimulation, lower medication costs and less patient burden. However, early clinical outcomes with IVM were suboptimal. More recently, clinical studies reported live birth rates after IVM of about 40%. New IVM culture systems are being used to improve the efficacy of IVM. These have been in widespread use for animals for many years and are now showing promise in the clinical setting. Patients more likely to benefit from IVM over IVF include those at risk of OHSS (e.g. women with polycystic ovary syndrome), when the time for ovarian stimulation is limited, or where sustained elevations of estradiol are contraindicated (e.g. oncofertility indications). The main barrier to use of IVM to date was its relative efficacy compared with IVF, and there have also been concerns over the health of infants born following IVM. However, no differences in congenital abnormalities between IVM and other ARTs have been identified. In addition, there is a lack of both experience and standardized protocols. Strategies to overcome barriers to the use of IVM include better training for clinicians, more and better funded research in the field, and improved recognition of IVM by fertility specialists. Overall, IVM offers a valuable alternative for ART in select patient populations. New approaches to IVM appear to have the potential to achieve pregnancy outcomes equivalent to those after IVF. Increasing the use of IVM in the future can be achieved with improved training and education for fertility specialists, and increased funding for IVM research, with the ultimate goal of improving fertility outcomes.

Characterization of circular RNA expression profiles in cumulus cells from patients with polycystic ovary syndrome

OBJECTIVE

To determine aberrant circular RNA (circRNA) expression profiles in cumulus cells from polycystic ovarian syndrome (PCOS) patients and identify their potential biological functions.

DESIGN

Circular RNAs microarray analysis of human tissue.

SETTING

University hospital.

PATIENT(S)

A total of 40 women, including 20 PCOS patients and 20 non-PCOS patients.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

A circRNA microarray containing probes that interrogate 21,442 human circRNAs to investigate differentially expressed circRNAs in cumulus cells, with potential target genes of significantly changed circRNAs and biological functions measured by microRNA support vector regression (mirSVR) and gene ontology (GO) analysis, with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis.

RESULT(S)

A total of 1,032 circRNAs were identified that were differentially expressed in PCOS cumulus cells, including 311 circRNAs increase and 721 circRNAs decrease (fold change ≥2). Four aberrantly expressed circRNAs reached a statistically significant result after Bonferroni correction (with Bonferroni correction, only circRNAs for which P < .05/21,442 = 2.3 × 10^-6 were considered statistically significant). Further analysis showed that aberrantly expressed circRNAs harbored microRNA binding sites, and some microRNAs were associated with PCOS. The GO and KEGG biological pathway analysis indicated that the genes with protein binding, mitotic nuclear envelope disassembly and metabolic pathways were statistically significantly enriched.

CONCLUSION(S)

Our data suggest that the aberrantly expressed circRNAs and their targeted genes might be associated with PCOS, providing new clues to find key diagnostic and therapeutic molecular biomarkers for PCOS patients.