Pregnancy and birth after intracytoplasmic sperm injection of in vitro matured germinal-vesicle stage oocytes: case report

Addition of rapamycin or co-culture with cumulus cells from younger reproductive age women does not improve rescue in vitro oocyte maturation or euploidy rates in older reproductive age women

Both spontaneously conceived pregnancies and those achieved using assisted reproduction decline with advancing maternal age. In this study, we tested if rapamycin and/or cumulus cells (CCs) from young donors could improve oocyte maturation and euploidy rates of germinal vesicle (GV) stage oocytes obtained from older women of reproductive age. A total of 498 GVs from 201 women >38 years (40.6 ± 1.8, mean ± SD) were included. GVs were randomly assigned into five groups for rescue IVM: control (with no CCs and no rapamycin); with autologous CCs; with autologous CCs and rapamycin; with CCs from young women (<35 years); and with CCs from young women and rapamycin. After 24 h of culture, the first polar body (PB) was biopsied in metaphase II oocytes, and the cytogenetic constitution was assessed using next-generation sequencing for both oocytes and PBs. Comparable maturation rates were found (56.2%, 60.0%, 46.5%, 51.7%, and 48.5% for groups 1-5, respectively; P = 0.30). Similarly, comparable euploidy rates were observed in the five groups (41.5%, 37.8%, 47.2%, 43.6%, and 47.8% for Groups 1-5, respectively; P = 0.87). Our findings indicate that rescue IVM is effective for obtaining mature euploid oocytes in older women of reproductive age, and that incubation with rapamycin or CCs obtained from young donors does not improve the maturation or euploidy rate.

In vitro maturation (IVM) of human immature oocytes: is it still relevant?

In vitro maturation (IVM) of human immature oocytes has been shown to be a viable option for patients at risk of ovarian hyperstimulation syndrome (OHSS), those seeking urgent fertility preservation and in circumstances where controlled ovarian stimulation is not feasible. Moreover, IVM techniques can be combined with ovarian tissue cryobanking to increase the chances of conception in cancer survivors. The clinical applications of IVM in the field of reproductive medicine are rapidly expanding and the technique is now classified as non-experimental. In contrast to conventional IVF (in vitro fertilization), IVM offers several advantages, such as reduced gonadotropin stimulation, minimal risk of ovarian hyperstimulation syndrome (OHSS), reduced treatment times and lower costs. However, the technical expertise involved in performing IVM and its lower success rates compared to traditional IVF cycles, still pose significant challenges. Despite recent advances, such as innovative biphasic IVM systems, IVM is still an evolving technique and research is ongoing to refine protocols and identify techniques to improve its efficiency and effectiveness. A comprehensive understanding of the distinct mechanisms of oocyte maturation is crucial for obtaining more viable oocytes through in vitro methods, which will in turn lead to significantly improved success rates. In this review, the present state of human IVM programs and future research directions will be discussed, aiming to promote a better understanding of IVM and identify potential strategies to improve the overall efficiency and success rates of IVM programs, which will in turn lead to better clinical outcomes.

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.

Embryo culture media differentially alter DNA methylating enzymes and global DNA methylation in embryos and oocytes

The effects of culture media on DNA methylation process, which is one of the epigenetic mechanisms, have not been clearly elucidated although it is known that in vitro culture conditions alter epigenetic mechanisms. This study was designed to address the question: does embryo culture media approach, sequential or single step, differentially affect DNA methylating enzymes and global DNA methylation. Mouse zygotes were cultured either in single step or sequential culture media until the blastocyst stage and in vivo developed blastocyst were utilized as control. Similarly, GV stage oocytes were in vitro matured either in single step or first step of sequential culture media. In vivo matured MII oocytes were used as control. The expression levels and cellular localization of Dnmt1 and 3a enzymes were analyzed by immunofluorescence and western blot analysis while global DNA methylation was evaluated by immunofluorescence. We found that signal intensities of Dnmt1 and Dnmt3a enzymes were significantly low in embryos or oocytes cultured in sequential media compared to single step media and control, which were comparable amongst themself. Similarly, global DNA methylation level in single step media and control groups was comparable but both was higher than the sequential media. This study demonstrated that composition of culture media may differentially affect DNA methylation levels in mouse embryos and oocytes. Since abnormal DNA methylation may cause aberrant oocyte or embryo development, we think that further studies are needed to test human embryos and oocyte, and to explain molecular mechanisms.

Prediction of ovarian response in IVF/ICSI cycles

Objective:

Our study aims to evaluate the various correlations between demographic, biochemical, ultrasound, and ovarian stimulation parameters with the percentage of mature oocytes in conventional stimulation for IVF/ICSI cycles in order to develop a predictive model to improve our understanding of the oocyte maturation process.

Methods:

This is a retrospective cohort study; patients underwent conventional antagonist ovarian stimulation protocols for fresh IVF/ICSI cycles. A total of 256 IVF/ICSI cycles were included. Age, antral follicle count (AFC), baseline serum follicle-stimulating hormone (FSH) levels, baseline serum luteinizing hormone (LH) levels, baseline serum estradiol (E2) levels, peak estradiol, P4 on hCG day, the body mass index (BMI), and stimulation length were measured. The variables were tested for correlations with the number of retrieved oocytes (#RO) and the number of mature oocytes (#MO). A backward stepwise regression was performed to identify the variables that correlated more strongly with percentage of mature oocytes (%MO).

Results:

A predictive equation was obtained with the variables that were not excluded in the model. % MO = 72.700 - 0.910 (Age) + 0.979 (BMI) + 1.209 (Baseline serum LH) - 0.647 (Progesterone on human Chorionic Gonadotropin day).

Conclusions:

We concluded that age, the BMI, baseline serum LH, and progesterone level on hCG day may predict %MO. Prospective studies are required to validate this predictive equation.

Single-cell RNA sequencing identifies molecular targets associated with poor in vitro maturation performance of oocytes collected from ovarian stimulation

STUDY QUESTION

What is the transcriptome signature associated with poor performance of rescue IVM (rIVM) oocytes and how can we rejuvenate them?

SUMMARY ANSWER

The GATA-1/CREB1/WNT signalling axis was repressed in rIVM oocytes, particularly those of poor quality; restoration of this axis may produce more usable rIVM oocytes.

WHAT IS KNOWN ALREADY

rIVM aims to produce mature oocytes (MII) for IVF through IVM of immature oocytes collected from stimulated ovaries. It is not popular due to limited success rate in infertility treatment. Genetic aberrations, cellular stress and the absence of cumulus cell support in oocytes could account for the failure of rIVM.

STUDY DESIGN, SIZE, DURATION

We applied single-cell RNA sequencing (scRNA-seq) to capture the transcriptomes of human in vivo oocytes (IVO) (n = 10) from 7 donors and rIVM oocytes (n = 10) from 10 donors. The effects of maternal age and ovarian responses on rIVM oocyte transcriptomes were also studied. In parallel, we studied the effect of gallic acid on the maturation rate of mouse oocytes cultured in IVM medium with (n = 84) and without (n = 85) gallic acid.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Human oocytes were collected from donors aged 28-41 years with a body mass index of <30. RNA extraction, cDNA generation, library construction and sequencing were performed in one preparation. scRNA-seq data were then processed and analysed. Selected genes in the rIVM versus IVO comparison were validated by quantitative real-time PCR. For the gallic acid study, we collected immature oocytes from 5-month-old mice and studied the effect of 10-μM gallic acid on their maturation rate.

MAIN RESULTS AND THE ROLE OF CHANCE

The transcriptome profiles of rIVM/IVO oocytes showed distinctive differences. A total of 1559 differentially expressed genes (DEGs, genes with at least 2-fold change and adjusted P < 0.05) were found to be enriched in metabolic processes, biosynthesis and oxidative phosphorylation. Among these DEGs, we identified a repression of WNT/β-catenin signalling in rIVM when compared with IVO oocytes. We found that oestradiol levels exhibited a significant age-independent correlation with the IVO mature oocyte ratio (MII ratio) for each donor. rIVM oocytes from women with a high MII ratio were found to have over-represented cellular processes such as anti-apoptosis. To further identify targets that contribute to the poor clinical outcomes of rIVM, we compared oocytes collected from young donors with a high MII ratio with oocytes from donors of advanced maternal age and lower MII ratio, and revealed that CREB1 is an important regulator. Thus, our study identified that GATA-1/CREB1/WNT signalling was repressed in both rIVM oocytes versus IVO oocytes and in rIVM oocytes of lower versus higher quality. Consequently we investigated gallic acid, as a potential antioxidant substrate in human rIVM medium, and found that it increased the mouse oocyte maturation rate by 31.1%.

LARGE SCALE DATA

Raw data from this study can be accessed through GSE158539.

LIMITATIONS, REASONS FOR CAUTION

In the rIVM oocytes of the high- and low-quality comparison, the number of samples was limited after data filtering with stringent selection criteria. For the oocyte stage identification, we were unable to predict the presence of oocyte spindle, so polar body extrusion was the only indicator.

WIDER IMPLICATIONS OF THE FINDINGS

This study showed that GATA-1/CREB1/WNT signalling was repressed in rIVM oocytes compared with IVO oocytes and was further downregulated in low-quality rIVM oocytes, providing us the foundation of subsequent follow-up research on human oocytes and raising safety concerns about the clinical use of rescued oocytes.

STUDY FUNDING/COMPETING INTEREST(S)

This work was supported by the Collaborative Research Fund, Research Grants Council, C4054-16G, and Research Committee Funding (Research Sustainability of Major RGC Funding Schemes), The Chinese University of Hong Kong. The authors have no conflicts of interest to declare.

Mitochondria in Ovarian Aging and Reproductive Longevity

Mitochondrial dysfunction is one of the hallmarks of aging. Consistently mitochondrial DNA (mtDNA) copy number and function decline with age in various tissues. There is increasing evidence to support that mitochondrial dysfunction drives ovarian aging. A decreased mtDNA copy number is also reported during ovarian aging. However, the mitochondrial mechanisms contributing to ovarian aging and infertility are not fully understood. Additionally, investigations into mitochondrial therapies to rejuvenate oocyte quality, select viable embryos and improve mitochondrial function may help enhance fertility or extend reproductive longevity in the future. These therapies include the use of mitochondrial replacement techniques, quantification of mtDNA copy number, and various pharmacologic and lifestyle measures. This review aims to describe the key evidence and current knowledge of the role of mitochondria in ovarian aging and identify the emerging potential options for therapy to extend reproductive longevity and improve fertility.

Effect of Human Testicular Cells Conditioned Medium on In Vitro Maturation and Morphology of Mouse Oocytes

Background

Testicular cell conditioned medium (TCCM) has been shown to induce female germ cell development in vitro from embryonic stem cells (ESCs). Testicular cells (TCs) secrete a variety of growth factors such as growth differentiation factor-9 (GDF-9), bone morphogenetic protein 4 (BMP-4), stem cell factor (SCF), leukemia inhibitory factor (LIF), and other, that could improve oocyte maturation. Here we have investigated the effect of human TCCM (hTCCM) on in vitro maturation (IVM) and morphology of mouse oocytes.

Materials and Methods

In this experimental study, 360 germinal vesicle (GV) oocytes were obtained from NMRI mice, aged 4-6 weeks that had received 5 IU pregnant mare's serum gonadotropin (PMSG) 48 hours before. GV oocytes were subjected to IVM. 120 GV oocytes were cultured in each medium; hTCCM as the test group, DMEM + 20%FBS as the control group and Ham’s F10 + HFF medium as the sham group. The rates of the IVM and perivi- telline space (PVS) changes were recorded at 8, 16 and 24 hours after culture. The metaphase II (MII) oocytes were subjected for in vitro fertilization (IVF) and the fertilization rate was evaluated after 1, 2, and 3 days.

Results

There was a significant difference between the maturation rates in hTCCM (31.67% MII) and the control [0% MII, P<0.05, (7.5% MI, 52.5% deg. and 40%GV)] groups but there was not a significant difference between the maturation rates in hTCCM and the sham group (53.33% MII, P>0.05). IVF success rate for MII oocytes obtained from IVM in the hTCCM group was 28.94% (n=11). Our data showed that hTCCM is an effective medium for GV oocyte growth and maturation compared to the control medium.

Conclusion

Our findings show that TCCM supports oocyte IVM in mice and affect oocyte morphology.

Intracytoplasmic sperm injection (ICSI) for non-male factor indications: a committee opinion

Intracytoplasmic sperm injection, while typically effective for overcoming low or absent fertilization in couples with a clear abnormality of semen parameters, is frequently used in combination with assisted reproductive technologies for other etiologies of infertility in the presence of semen parameters that meet the World Health Organization 2010 normative reference values. This committee opinion provides a critical review of the literature, where available, to identify situations where this may or may not be of benefit. This document replaces the previously published document of the same name, last published in 2012 (Fertil Steril 2012;98:1395-9).

Fertilisation and early embryonic development of immature and rescue in vitro-matured sibling oocytes

The objective of this study was to assess the effect of rescue in vitro maturation and immediate intracytoplasmic sperm injection (ICSI) application on fertilisation success and early embryonic development of metaphase I (MI) oocytes. This was a retrospective cohort study including 2425 sibling oocytes in 259 ICSI cycles. ICSI was performed on 104 GV (germinal vesicle) oocytes which had reached the metaphase II (MII) stage (Group 1) and 231 MI oocytes which had reached the MII stage (Group 2) following IVM (in vitro maturation). Immediate ICSI was applied following oocyte aspiration on 292 MI stage (Group 3) and 1798 MII stage oocytes (Group 4). Normal fertilisation rates in Groups 1, 2, 3 and 4 were 51.9%, 39%, 30.1% and 59.5%, respectively. The rates of blastocyst development per oocyte and per zygote were calculated as 3.8%, 3.0%, 6.8%, 14.1% and 7.4%, 7.7%, 22.7%, 23.6% for Groups 1, 2, 3 and 4, respectively. The blastocyst development rate was significantly higher in the MI-ICSI group compared with other immature oocytes. Even though performing ICSI on the oocytes at the MI stage on the day of oocyte aspiration resulted in lower fertilisation rates, it was associated with significantly higher rates of blastocyst development.

Immature Oocyte for Fertility Preservation

In vitro maturation (IVM) of human immature oocytes has been offered to women who are at risk of developing ovarian hyperstimulation syndrome (OHSS) caused by gonadotropin stimulation, such as PCO(S) patients or who have poor ovarian reserve. Cryopreservation of oocytes matured in vivo obtained in IVF cycles has improved after implementing the vitrification method and many successful results have been reported. Now, this procedure can be successfully offered to fertility preservation programs for patients who are in danger of losing their ovarian function due to medical or social reasons, and to oocyte donation programs. This vitrification technique has also been applied to cryopreserve oocytes obtained from IVM program. Some advantages of oocytes vitrification related with IVM are: (1) eliminating costly drugs and frequent monitoring; (2) completing treatment within 2 to 10 days (3) avoiding the use of hormones in cancer patients with hormone-sensitive tumors; and (4) retrieving oocytes at any point in menstrual cycle, even in the luteal phase. In addition, immature oocytes can also be collected from extracorporeal ovarian biopsy specimens or ovaries during caesarian section. Theoretically, there are two possible approaches for preserving immature oocytes: oocyte cryopreservation at the mature stage (after IVM) and oocyte cryopreservation at the Germinal Vesicle (GV)-stage (before IVM). Both vitrification of immature oocyte before/after IVM is not currently satisfactory. Nevertheless, many IVF centers worldwide are doing IVM oocyte cryopreservation as one of the options to preserve fertility for female cancer. Therefore, more studies are urgently required to improve IVM- and vitrification method to successfully preserve oocytes collected from cancer patients. In this review, present oocyte maturation mechanisms and recent progress of human IVM cycles will be discussed first, followed by some studies of the vitrification of human IVM oocyte.

In vitro maturation in subfertile women with polycystic ovarian syndrome undergoing assisted reproduction

BACKGROUND

Polycystic ovarian syndrome (PCOS) occurs in 4% to 7% of all women of reproductive age and 50% of women presenting with subfertility. Subfertility affects 15% to 20% of couples trying to conceive. A significant proportion of these women ultimately need assisted reproductive technology (ART). In vitro fertilisation (IVF) is one of the assisted reproduction techniques employed to raise the chances of achieving a pregnancy. For the standard IVF technique, stimulating follicle development and growth before oocyte retrieval is essential, for which a large number of different methods combining gonadotrophins with a gonadotrophin-releasing hormone (GnRH) agonist or antagonist are used. In women with PCOS, the supra-physiological doses of gonadotrophins used for controlled ovarian hyperstimulation (COH) often result in an exaggerated ovarian response, characterised by the development of a large cohort of follicles of uneven quality, retrieval of immature oocytes, and increased risk of ovarian hyperstimulation syndrome (OHSS). A potentially effective intervention for women with PCOS-related subfertility involves earlier retrieval of immature oocytes at the germinal-vesicle stage followed by in vitro maturation (IVM). So far, the only data available have derived from observational studies and non-randomised clinical trials.

OBJECTIVES

To assess the effectiveness and safety of IVM followed by IVF or ICSI versus conventional IVF or ICSI among women with PCOS undergoing assisted reproduction.

SEARCH METHODS

This is the second update of this review. We performed the search on 17 April 2018.The search was designed with the help of the Cochrane Gynaecology and Fertility Group Information Specialist, for all published and unpublished randomised controlled trials (RCTs).We searched the the Cochrane Gynaecology and Fertility Group Specialised Register of controlled trials, CENTRAL via the Cochrane Central Register of Studies Online, MEDLINE, Embase, CINAHL, and the trial registers for ongoing and registered trials and the Open Grey database for grey literature from Europe. We made further searches in the 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 PubMed and Google for any recent trials that have not yet been indexed in the major databases.

SELECTION CRITERIA

All RCTs on the intention to perform IVM before IVF or ICSI compared with conventional IVF or ICSI for subfertile women with PCOS, irrespective of language and country of origin.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed risk of bias, extracted data from studies, and attempted to contact the authors of studies for which data were missing. Our primary outcomes were live birth per woman randomised and miscarriage. We performed statistical analysis using Review Manager 5. We assessed evidence quality using GRADE methods.

MAIN RESULTS

We found two RCTs suitable for inclusion in the review and six ongoing trials that have not yet reported results. Both included studies were published as abstracts in international conferences.Both studies were at unclear or high risk of bias for most of the seven domains assessed. Common problems were unclear reporting of study methods and lack of blinding. The main limitations in the overall quality of the evidence were high risk of bias and serious imprecision.There were no data on the primary outcomes of this review, namely live birth per woman randomised and miscarriage.Both studies reported clinical pregnancy rate: there was evidence of an effect between IVM and IVF, favouring the former (odds ratio 3.10, 95% confidence interval 1.06 to 9.00; 71 participants; 2 studies; I² = 0%; very low-quality evidence). The incidence of OHSS was zero in both studies in both groups.There were no data for the other outcomes specified in this review.

AUTHORS' CONCLUSIONS

Though promising data on the in vitro maturation (IVM) technique have been published, unfortunately there is still no evidence from properly conducted randomised controlled trials upon which to base any practice recommendations regarding IVM before in vitro fertilisation (IVF) or intracytoplasmic sperm injection for women with polycystic ovarian syndrome. Regarding our secondary outcomes, very low-quality evidence showed that clinical pregnancy was higher with IVM when compared to IVF, whereas the incidence of ovarian hyperstimulation syndrome was zero in both studies in both groups. We are awaiting the results of six ongoing trials and eagerly anticipate further evidence from good-quality trials in the field.

Do immature and mature sibling oocytes recovered from stimulated cycles have the same reproductive potential?

RESEARCH QUESTION

How can laboratory and clinical outcomes of spontaneously, early maturing germinal-vesicle oocytes and sibling in-vivo-matured (metaphase II [MII]) oocytes be quantified and compared?

DESIGN

A prospective, non-randomized intra-cohort study of oocytes from women aged 38 years or younger, with six or fewer MII oocytes and four or more germinal vesicles retrieved. No indication was identified for genetic tests or oocyte or embryo cryopreservation. The study was carried out at IVIRMA-Valencia. Early maturing germinal vesicles were selected for reproductive purposes. In vitro- and in-vivo MII oocytes were fertilized. After time-lapse culture, hatching blastocysts from germinal vesicles were biopsied for aneuploidy screening and vitrified. Laboratory and clinical outcomes were compared according to oocyte origin.

RESULTS

Almost 70% of germinal vesicles had matured early and spontaneously, and had comparable in vitro-outcomes and morphokinetics to sibling in vivo-matured oocytes. Fifty per cent of biopsied blastocysts were euploid. Germinal-vesicle rescue increased the number of MII oocytes per cycle to 3.9, finally adding one extra-blastocyst per cycle. A live birth confirmed the feasibility of this approach. Further data, however, are needed to quantify its real contribution to standard intracytoplasmic sperm injection cycles. Nevertheless, 40% of patients obtained either an immediate advantage (reduction of cancellation rate) or long-term benefit (availability of extra blastocysts of attempts).

CONCLUSIONS

Germinal-vesicle rescue can be considered as a complementary approach when folliculometry (expected) and number of MII (observed) are unequal.

Quality of common marmoset (Callithrix jacchus) oocytes collected after ovarian stimulation

The common marmoset (Callithrix jacchus) is an experimental animal that is considered suitable for the creation of next-generation human disease models. It has recently been used in the reproductive technology field. Oocytes can be effectively collected from female marmosets via ovarian stimulation with injections of follicle-stimulating hormone (FSH) and human chorionic gonadotropin (hCG). The oocytes, collected about 28 h after the hCG injection, include both premature oocytes and postmature (in vivo matured; IVO) oocytes, and the premature oocytes can be matured by in vitro culture (in vitro matured; IVM). Although IVM and IVO oocytes are equivalent in appearance at the MII stage, it remains unclear whether there are differences in their properties. Therefore, we investigated their in vitro fertilization and developmental capacities and cytoskeletal statuses. Our findings revealed that the IVM and IVO oocytes had similar fertilization rates but that no IVO oocytes could develop to the blastocyst stage. Additionally, IVO oocytes showed abnormal cytoskeletal formation. It is concluded that IVM oocytes maintain normal function, whereas IVO oocytes would be affected by aging and other factors when they remain for a long time in the ovary.

Pregnancy and fertilization potential of immature oocytes retrieved in intracytoplasmic sperm injection cycles

OBJECTIVE

The goal of this study was to evaluate the pregnancy potential of immature (metaphase I or germinal vesicle stage) oocytes retrieved in intracytoplasmic sperm injection (ICSI) cycles.

METHODS

A total of 1,871 couples with infertility underwent 2,984 ICSI cycles. Cycles in which three or fewer oocytes were retrieved were included in this study in order to evaluate the pregnancy potential of immature oocytes. Cycles were divided into five groups (group I-V), according to the maturation status of the oocytes at the time of cumulus cell removal and ICSI. The fertilization and pregnancy rates after ICSI were analyzed and compared among the study groups based on the maturation status of the retrieved oocytes.

RESULTS

The retrieval of only immature oocytes was associated with a significant decrease in the fertilization rate (76.1%±37.3% vs. 49.0%±49.1%, 66.7%±48.7%; group I vs. group II, group III, respectively) and the average number of transferred embryos (1.5±0.7 vs. 1.1±0.4, 1.1±0.6). The cycle cancellation rate was significantly higher when only immature oocytes were retrieved. The clinical pregnancy rate decreased significantly when the transferred embryos had originated from immature oocytes (16.9% vs. 10.3%, 1.2%).

CONCLUSION

In ICSI cycles, the fertilization potential and pregnancy potential of the immature oocytes retrieved in ICSI cycles were inferior to those of mature oocytes. Therefore, increasing the number of injectable oocytes and transferrable embryos by using immature oocytes after their spontaneous in vitro maturation does not necessarily improve pregnancy outcomes.

In vitro maturation of immature human oocytes for clinical application

Meiotic progression in the oocyte is defined as oocyte maturation from reinitiation of the first meiotic division from the germinal vesicle (GV) stage to the metaphase-II (M-II) stage (Fig. 1), (Cha and Chian, Hum Reprod Update 4:103-120, 1998). Priming with FSH or HCG prior to immature oocyte retrieval improves oocyte maturation and pregnancy rates. The size of follicles may be an important feature for IVM treatment. The combination of natural-cycle IVF with immature oocyte retrieval followed by IVM is an attractive treatment for young women with all types of infertility without recourse to ovarian stimulation with an acceptable pregnancy rate.

In vitro maturation in subfertile women with polycystic ovarian syndrome undergoing assisted reproduction

BACKGROUND

Polycystic ovarian syndrome (PCOS) occurs in 4% to 7% of all women of reproductive age and 50% of women presenting with subfertility. Subfertility affects 15% to 20% of couples trying to conceive. A significant proportion of these women ultimately need assisted reproductive technology (ART). In vitro fertilisation (IVF) is one of the assisted reproduction techniques employed to raise the chances of achieving a pregnancy. For the standard IVF technique, stimulating follicle development and growth before oocyte retrieval is essential, for which a large number of different methods combining gonadotrophins with a gonadotrophin-releasing hormone (GnRH) agonist or antagonist are used. In women with PCOS, the supra-physiological doses of gonadotrophins used for controlled ovarian hyperstimulation (COH) often result in an exaggerated ovarian response, characterised by the development of a large cohort of follicles of uneven quality, retrieval of immature oocytes, and increased risk of ovarian hyperstimulation syndrome. A potentially effective intervention for women with PCOS-related subfertility involves earlier retrieval of immature oocytes at the germinal-vesicle stage followed by in vitro maturation (IVM). So far, the only data available have derived from observational studies and non-randomised clinical trials.

OBJECTIVES

To compare outcomes associated with in vitro maturation (IVM) followed by vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) versus conventional IVF or ICSI, among women with polycystic ovarian syndrome (PCOS) undergoing assisted reproductive technologies (ART).

SEARCH METHODS

We searched the Menstrual Disorders and Subfertility Group (MDSG) Specialised Register of controlled trials to May 2013 for any relevant trials identified from the title, abstract, or keyword sections. This was followed by a search of the electronic database MEDLINE, EMBASE, LILACS and CINAHL, without language restriction. We also performed a manual search of the references of all retrieved articles; sought unpublished papers and abstracts submitted to international conferences, searched the clinicaltrials.gov and WHO portal registries for submitted protocols of clinical trials, and contacted experts. In addition, we examined the National Institute of Clinical Excellence (NICE) fertility assessment and treatment guidelines and handsearched reference lists of relevant articles (from 1970 to May 2013).

SELECTION CRITERIA

All randomised trials (RCTs) on the intention to perform IVM before IVF or ICSI compared with conventional IVF or ICSI for subfertile women with PCOS.

DATA COLLECTION AND ANALYSIS

Three review authors (CS, MK and NV) independently assessed eligibility and quality of trials. Primary outcome measure was live birth rate per randomised woman.

MAIN RESULTS

There were no RCTs suitable for inclusion in the review, although there are currently three ongoing trials that have not yet reported results.

AUTHORS' CONCLUSIONS

Though promising data on the IVM technique have been published, unfortunately there is still no evidence from RCTs upon which to base any practice recommendations regarding IVM before IVF or ICSI for women with PCOS. Meanwhile, the results of the above-mentioned ongoing trials are awaited and, of course, further evidence from good quality trials in the field is eagerly anticipated.

Developmental potential of in vitro or in vivo matured oocytes

This study compared the embryological features of mature and immature oocytes (different stages) collected from stimulated cycles of in vitro fertilization (IVF). Immature oocytes were identified, classified as PI (prophase I – germinal vesicle, GV) or MI (metaphase I), were matured in vitro and fertilized using the intra-cytoplasmic sperm injection (ICSI) technique. Fertilization potential, cleavage, and subsequent transfer/cryopreservation of the embryos derived from these in vitro matured oocytes were compared with those of in vivo matured oocytes (collected at the MII stage). The characteristics of embryos derived from gametes recovered in the MI and MII stages were similar. The fertilization rate of immature oocytes recovered in PI was significantly lower than that of MII oocytes (P = 0.031), and the cleavage rate of the PI group was also lower than that of the MI (P = 0.004) and MII (P < 0.001) groups. In vitro maturation of MI oocytes is a suitable alternative when immature oocytes are recovered, as their characteristics and development are similar to those of in vivo matured oocytes. Optimization of outcomes for PI oocytes will require development of techniques that can distinguish which of these gametes will mature and fertilize.

Fertilization and pregnancy potential of immature oocytes from stimulated intracytoplasmic sperm injection cycles

OBJECTIVE

We evaluated the fertilization potential of immature oocytes obtained from controlled ovarian hyperstimulation cycles of patients undergoing ICSI.

METHODS

We retrospectively analyzed 463 ICSI cycles containing at least one immature oocyte at oocyte denudation. ICSI was performed on mature oocytes at oocyte denudation (metaphase-II [MII] oocytes) and the oocytes that extruded the first polar body between oocyte denudation and ICSI (MI-MII oocytes). Fertilization and early embryonic development were compared between MII and MI-MII oocytes. To investigate the pregnancy potential of MI-MII oocytes, the pregnancy outcome was analyzed in 24 ICSI cycles containing only immature oocytes at retrieval.

RESULTS

The fertilization rate of MI-MII oocytes (37.0%) was significantly lower than that of MII oocytes (72.3%). The rates of delayed embryos and damaged embryos did not significantly differ. Eighty-one immature oocytes were retrieved in 24 cycles that retrieved only immature oocytes and 61 (75.3%) of them were in the MI stage. ICSI was performed on 36 oocytes (59.0%) that extruded the first polar body before ICSI and nine MI-MII oocytes (25.0%) were fertilized. Embryo transfers were performed in five cycles. Pregnancy was observed in one cycle, but it ended in biochemical pregnancy.

CONCLUSION

In ICSI cycles, oocytes that extruded the first polar body between denudation and ICSI can be used as a source of oocytes for sperm injection. However, their fertilization and pregnancy potential are lower than that of mature oocytes. Therefore, ovarian stimulation should be performed carefully for mature oocytes obtained at retrieval, especially in cycles with a small number of retrieved oocytes.

Optimizing human oocyte cryopreservation for fertility preservation patients: should we mature then freeze or freeze then mature?

OBJECTIVE

To evaluate the maturation and post-thaw survival rates of immature oocytes to determine whether in vitro maturation (IVM) should be attempted prior to or after cryopreservation.

DESIGN

Nonrandomized observational study.

SETTING

Private academic and clinical reproductive center.

PATIENT(S)

Patients (n = 71) who donated immature unusable oocytes after vaginal oocyte retrieval (VOR) after undergoing controlled ovarian hyperstimulation using a standard GnRH antagonist protocol.

INTERVENTION(S)

Germinal vesicle (GV), metaphase I (MI), and metaphase II (MII) oocytes (n = 175) were obtained from consenting IVF patients for fresh IVM, post-thaw IVM, or control group. In the fresh IVM group, GV- and MI- stage oocytes (n = 69) were cultured for 24 hours, matured in vitro (IVM-MII), cryopreserved, thawed, and evaluated for survival. In the post-thaw IVM group, GV- and MI- stage oocytes (n = 27) were frozen on day 0, thawed, evaluated for survival, and cultured for 24-hour IVM. MII donor oocytes (n = 79) were cryopreserved and thawed as a control.

MAIN OUTCOME MEASURE(S)

Survival postfreeze and oocyte development to the MII stage was analyzed using a χ(2) analysis.

RESULT(S)

Fresh IVM had a significantly higher maturation rate than post-thaw IVM.

CONCLUSION(S)

Oocyte cryopreservation is important for patients at risk of ovarian cancer, elective fertility preservation, and, potentially, for ovum donation. The superior maturation rate of GV and MI oocytes in the fresh versus post-thaw groups provides strong evidence for maturing oocytes to the MII stage before cryopreservation.

Intracytoplasmic sperm injection (ICSI) for non-male factor infertility: a committee opinion

Intracytoplasmic sperm injection, while typically effective for overcoming low or absent fertilization in couples with a clear abnormality of semen parameters, is frequently utilized in combination with assisted reproductive technologies for other etiologies of infertility in the presence of normal semen parameters. This committee opinion provides a critical review of the literature, where available, to identify situations where this may or may not be of benefit.

The dynamics of in vitro maturation of germinal vesicle oocytes

OBJECTIVE

To evaluate the dynamics of the nuclear maturation (NM) of in vitro-matured (IVM) oocytes and to determine the most favorable duration of meiosis II (MII) arrest in relation to the normal activation response.

DESIGN

Experimental.

SETTING

University-affiliated infertility clinic.

PATIENT(S)

Donated immature germinal vesicle oocytes (GV).

INTERVENTION(S)

The GV underwent spontaneous IVM and the dynamics of NM studied by real-time monitoring. The IVM oocytes were parthenogenetically activated at different MII arrest points and their response assessed.

MAIN OUTCOME MEASURE(S)

Moment of GV breakdown; extrusion of the first polar body; duration of MI and MII arrest; activation rate (AR) and type.

RESULT(S)

Two GV populations-early (E-IVM, 18.4 ± 2.7 hours) and late (L-IVM, 26.3 ± 3.8 hours) maturing-were defined according to the time required for extrusion of the first polar body. Significantly more E-IVM than L-IVM exhibited a normal activation response (61.3% vs. 34.6%), but AR were similar (average, 88.6%) in both groups. Duration of the GV stage differed between the two groups, but MI arrest (14.0 ± 0.3 hours) was constant. The E-IVM arrested at MII for at least 4.3 hours displayed significantly lower AR and similar normal activation rates (61.3%) to E-IVM arrested for a shorter time (83.9% vs. 100%). The L-IVM displayed a similar AR (80.8%), but lower normal activation rates than E-IVM (34.6%), regardless of when activation took place.

CONCLUSION(S)

The success of IVM depends on the NM timing rather than on the length of MII arrest.

Prognosis for clinical pregnancy and birth after transferring embryos derived from a cohort of incompletely mature oocytes at retrieval time

The purpose of this retrospective study was to establish a prognosis for implantation, pregnancy and live birth rates in stimulated IVF cycles after transferring embryos derived from: 1/ retrieved immature oocytes that matured overnight in vitro (late mature group: LM); 2/ retrieved immature oocytes that matured overnight in vitro and were added to the embryos derived from retrieved mature oocytes (mixed embryos group: MX); and 3/ retrieved mature oocytes (mature group: M). The obtained implantation, clinical pregnancy and live birth rates for the LM group were: 5.6%, 11.4%, 11.4%; for the MX group were: 4.2%, 14.6%, 11.6%; and for the M group were: 14.6%, 45.2% and 33.3%, respectively. These measurements were significantly lower p<0.05 for the LM and MX groups in comparison to the M group. The number of oocytes retrieved and the number of embryos transferred were the lowest (p<0.001-0.05) for the LM group. It is concluded, that the retrieved immature oocytes are able to mature during overnight culture in vitro, be fertilized and provide developmentally competent embryos with the prognosis of 11% for the successful delivery.

Commercially available enhanced in vitro maturation medium does not improve maturation of germinal vesicle and metaphase I oocytes in standard in vitro fertilization cases

Improvements in in vitro maturation techniques have focused on culture optimization to increase oocyte maturation rates. Specialized culture media, now commercially available, did not perform significantly better than standard IVF culture media for maturation of immature oocytes in our normal IVF cases.

The nuclear mitotic apparatus (NuMA) protein: localization and dynamics in human oocytes, fertilization and early embryos

The oocyte's meiotic spindle is a dynamic structure that relies on microtubule organization and regulation by centrosomes. Disorganization of centrosomal proteins, including the nuclear mitotic apparatus (NuMA) protein and the molecular motor complex dynein/dynactin, can lead to chromosomal instability and developmental abnormalities. The present study reports the distribution and function of these proteins in human oocytes, zygotes and early embryos. A total of 239 oocytes, 90 zygotes and discarded embryos were fixed and analyzed with confocal microscopy for NuMA and dynactin distribution together with microtubules and chromatin. Microtubule-associated dynein-dependent transport functions were explored by inhibiting phosphatase and ATPase activity with sodium-orthovanadate (SOV). At germinal vesicle (GV) stages, NuMA was dispersed across the nucleoplasm. After GV breaks down, NuMA became cytoplasmic before localizing at the spindle poles in metaphase I and II oocytes. Aberrant NuMA localization patterns were found during oocyte in vitro maturation. After fertilization, normal and abnormal pronuclear stage zygotes and embryos displayed translocation of NuMA to interphase nuclei. SOV treatment for up to 2 h induced lower maturation rates with chromosomal scattering and ectopic localization of NuMA. Accurate distribution of NuMA is important for oocyte maturation, zygote and embryo development in humans. Proper assembly of NuMA is likely necessary for bipolar spindle organization and human oocyte developmental competence.

Evaluation of the developmental potential of metaphase I oocytes from stimulated intracytoplasmic sperm injection cycles

The objective of the present study was to evaluate the developmental potential and clinical application value of metaphase I (MI) oocytes obtained from stimulated intracytoplasmic sperm injection (ICSI) cycles. ICSI was performed on MI oocytes immediately after denudation (Group A), or on in vitro-matured (IVM) oocytes following culture; oocytes in culture were further divided into two groups, being cultured for either 3–5 h (Group B) or 24–28 h (Group C). Metaphase II oocytes from the same cycle(s) isolated for ICSI served as the control group (Group D). The rates of normal fertilisation, cleavage and high-quality embryos were compared among the four groups. High-quality embryos were transferred whenever possible, and pregnancy rates were evaluated. Results showed that normal fertilisation rates for Groups B, C and D were significantly higher than that of Group A (68.6%, 57.8%, 74.5% and 30.1%, respectively; P < 0.01). The rate of high-quality embryos in Group B was comparable with Group D; the rate for Group C was significantly lower than that of the other groups (P < 0.05). Two clinical pregnancies were achieved after transfer of embryos from IVM oocytes. In vitro maturation of MI oocytes for a short period of time may increase the number of available embryos; however, overnight in vitro culture of MI oocytes did not improve results.

In Vitro Maturation of Human Immature Oocytes

Ovarian stimulation regimes may be hazardous to a small proportion of women or may result in side effects. For such women IVM is recommended. IVM technology can be divided into two main approaches, namely (i) FSH and (ii) hCG priming. These two approaches improve oocyte maturation and pregnancy rates when the immature oocytes are retrieved from women with PCOS. Although the size of follicles appears to be important for subsequent embryonic development however the developmental competence of oocytes derived from the small antral follicles seems not to be adversely affected by the presence of a dominant follicle. In general, the clinical pregnancy and implantation rates per ET are now in the order of 35–40% and 10–15% respectively in women with PCOS following IVM. The combination of natural cycle IVF with immature oocyte retrieval followed by IVM is an attractive treatment alternative for women with various forms of infertility without recourse to ovarian stimulation. Natural cycle IVF/M together with IVM alone can be used to treat more than half of the population of infertile patients with acceptable pregnancy rate. Approximately 2,000 healthy infants have been born following immature oocyte retrieval and IVM.

Spontaneous in vitro maturation and artificial activation of human germinal vesicle oocytes recovered from stimulated cycles

PURPOSE

To define germinal vesicles (GV) by morphometric and morphologic examination and by chromatin compaction and to assess their spontaneous nuclear and cytoplasmic competence.

MATERIALS

131 GV were cultured for 42.7 ± 2.4 h. Nuclear maturation was evaluated at four time points. Sixty-seven in vitro and twenty-five in vivo metaphase II (MII) were activated. Parthenotes with 2 PB and one pronucleus (NA) were studied for ploidy.

RESULTS

A total of 74.8% GV matured to MII: 55% at 21.4 ± 2.4 h and 47.3% in the following 24 h. Artificial activation induced NA in 79.2% of in vivo-MII and in 22.4% of in vitro-MII. All NA were haploid.

CONCLUSIONS

GV spontaneously mature at the nuclear level. Their NA are haploid, but their cytoplasmic competence is compromised. Variables were not found to be predictors of oocyte competence, probably due to our population being homogeneous with respect to most of the variables studied.

Healthy live birth from vitrified blastocysts produced from natural cycle IVF/IVM

Natural-cycle IVF combined with in-vitro maturation (natural-cycle IVF/IVM) was used as a treatment for a 27-year-old woman. She was administered 10,000 IU of human chorionic gonadotrophin intramuscularly about 36 h prior to oocyte collection and oocyte collection was performed on day 11 of her menstrual cycle. One mature oocyte was retrieved from the leading follicle and another five mature oocytes and six immature oocytes were retrieved from the rest of the follicles. Out of 10 fertilized zygotes, eight of them cleaved. Three day-3 embryos derived from in-vivo matured oocytes (one was from the leading follicle) were transferred but failed to conceive. The remaining five embryos were continuously cultured until day 6 and four of them developed to the expanded blastocyst stage and vitrified for the storage. Six months later, two vitrified-warmed blastocysts derived from the immature oocytes were transferred and resulted in the full-term delivery of a healthy female infant. This case report for the first time indicates that blastocysts produced from the immature oocytes retrieved from the small follicles, when a leading follicle exists in the ovaries, can be vitrified to produce a healthy live birth, suggesting that natural-cycle IVF/IVM is an efficient infertility treatment.

In vitro maturation in sub fertile women with polycystic ovarian syndrome undergoing assisted reproduction

BACKGROUND

Polycystic ovarian syndrome (PCOS) occurs in 4% to 7% of all women of reproductive age and 20% of women presenting with sub-fertility. A significant proportion of these women will ultimately need assisted reproductive techniques (ART). In women with PCOS, the supra-physiological doses of gonadotrophins used for controlled ovarian hyperstimulation (COH) often result in an exaggerated ovarian response characterised by the development of a large cohort of follicles of uneven quality, retrieval of immature oocytes, and increased risk of ovarian hyperstimulation syndrome. A potentially useful intervention for women with PCOS-related infertility involves earlier retrieval of immature oocytes followed by in vitro maturation (IVM).

OBJECTIVES

To compare live birth rates per woman following in vitro maturation (IVM) with conventional in vitro fertilisation (IVF) or intracytoplasmic sperm injection (ICSI) for women with PCOS undergoing ART.

SEARCH STRATEGY

We searched the Menstrual Disorders and Subfertility Group Specialised Register of controlled trials for any relevant trials from the title, abstract, or keyword sections. Following a search of electronic databases (MEDLINE in all languages) using Ovid software we also performed a manual search of the references of all retrieved articles, sought unpublished papers and abstracts submitted to international conferences, and contacted experts. In addition, we searched the National Institute of Clinical Excellence fertility assessment and treatment guidelines (NICE 2004) and handsearched reference lists of relevant systematic reviews and randomised trials.

SELECTION CRITERIA

All randomised trials on the intention to perform IVM before IVF or ICSI and conventional IVF or ICSI for sub-fertile women with PCOS.

DATA COLLECTION AND ANALYSIS

We identified no studies that met the inclusion criteria.

MAIN RESULTS

There were no trials suitable for inclusion in the review.

AUTHORS' CONCLUSIONS

There are no randomised controlled trials upon which to base any practice recommendations regarding IVM before IVF or ICSI for women with PCOS. There is an urgent need for randomised trials in this field.

Selected aspects of advanced porcine reproductive technology

In vitro fertilization (IVF) of in vitro matured (IVM) oocytes in pigs has become the most popular method of studying gametogenesis and embryogenesis in this species. Furthermore, because of recent advances in in vitro culture (IVC) of IVM-IVF embryos, in vitro production (IVP) of embryos now enables us to generate viable embryos as successfully as for in vivo-derived embryos and with less cost and in less time. These technologies contribute not only to developments in reproductive physiology and agriculture but also to the conservation of porcine genetic resources and the production of cloned or genetically modified pigs. However, in IVP, there still remains the problem of abnormal ploidy, which is caused by performing procedures under non-physiological conditions. In recent years, unique technologies such as intracytoplasmic sperm injection (ICSI) or xenografting of gonadal tissue into immunodeficient experimental animals have been developed to help conserve gamete resources. These technologies combined with IVP are expected to be useful for the conservation of gametes from important genetic resources. Here, we discuss the developmental ability and normality of porcine IVP embryos and also the utilization of ICSI and xenografting in advancing biotechnology in pigs.

Successful delivery after the transfer of embryos obtained from a cohort of incompletely in vivo matured oocytes at retrieval time

OBJECTIVE

To report a case of successful delivery of a healthy baby after intracytoplasmic sperm injection (ICSI) in a patient with no mature oocytes at the time of oocyte retrieval.

DESIGN

Case report.

SETTING

Department of Reproductive Medicine.

PATIENT

After a controlled ovarian hyperstimulation cycle, a total of seven immature oocytes were collected.

INTERVENTION(S)

Medical management.

MAIN OUTCOME MEASURE(S)

The timing of polar body extrusion was checked every 2 hours, and ICSI was performed as soon as the first polar body was extruded.

RESULT(S)

Following incubation in culture medium, five oocytes reached the metaphase II stage within 8-8.5 hours. Three oocytes were fertilized after ICSI, and two of three cleaved embryos were transferred on day 3. The embryo transfer was followed by a single pregnancy and the delivery of a healthy baby.

CONCLUSION

This case report demonstrates that embryos obtained from in vitro matured oocytes retain the developmental competence for full-term. It illustrates the importance of regularly monitoring the polar body extrusion when all collected oocytes are immature.

How safe is germinal vesicle stage oocyte rescue? Aneuploidy analysis of in vitro matured oocytes

OBJECTIVE

To evaluate the rate and type of aneuploidies of chromosomes 13, 16, 18, 21 and 22, with respect to the length of in vitro maturation (IVM) period, and to compare the results to previously published studies on aneuploidy rates of unfertilized, uninseminated mature oocytes and first polar bodies.

STUDY DESIGN

Two hundred and twelve immature germinal vesicle stage oocytes were assigned to two groups. After successful IVM, depending on their maturational period of 24h (Group A) or 36h (Group B), chromosomal analysis was performed by five color fluorescence in situ hybridization (FISH). In Groups A and B the rates of aneuploid oocytes were calculated and compared by chi-square test. Also the rates of hyperhaploidy, hypohaploidy, disomy and nullisomy were determined and compared by chi-square test. The difference was considered statistically significant at p-value of <0.05.

RESULTS

The prolonged IVM did not significantly affect the aneuploidy rate compared to the shorter maturation period (48.1% and 45.0%, respectively). Regarding the unbalanced premature chromatid separation, no statistically significant difference was found between hyperhaploidy and hypohaploidy (14.8% versus 8.3%). For chromosome nondisjunction, higher frequency of disomy than nullisomy was observed (30.6% versus 14.8%; p<0.05). The estimated global aneuploidy rate was between 42% and 63%.

CONCLUSIONS

The aneuploidy rate of IVM GV-oocytes is comparable to the aneuploidy rate of in vivo matured oocytes and first polar bodies, regardless of the length of maturation period. This suggests that the immature oocytes can be used in infertility treatment after they complete maturation.

Influence of well defined protein source on in vitro maturation of human oocyte: human follicular fluid versus human serum albumin

OBJECTIVE

To compare developmental competency of immature human oocytes matured in vitro in G2 media supplemented by two different protein sources.

DESIGN

Retrospective comparative study.

SETTING

University Hospital IVF program.

PATIENT(S)

Sixty-five consecutive women from whom at least one immature oocyte was obtained during 76 cycles of ovarian hyperstimulation and IVF.

INTERVENTION(S)

G2 media containing human follicular fluid (hFF) (from January to August 2005) or human serum albumin (HSA) (from Sep 2005 to Aug 2006) were used for in vitro maturation of immature oocytes.

MAIN OUTCOME MEASURE(S)

In vitro maturation rate of immature oocytes and their fertilization rate.

RESULT(S)

A total of 231 immature oocytes including 107 germinal vesicle (GV) stage and 124 metaphase I (MI) were cultured in vitro and then fertilized by intracytoplasmic sperm injection. The in vitro maturation rate of GV (40.6% vs. 52.0%) and MI oocytes (84.4% vs. 70.0%) and the fertilization rate in GV (76.9% vs. 48.7%) and MI oocytes (70.4% vs. 73.4%) were not different between hFF- and HSA-supplemented G2 media. The cleavage rates of embryos generated from either GV or MI were similar between the two groups, but they were seldom used in embryo transfer.

CONCLUSION(S)

Developmental competency of immature oocytes was comparable when matured in vitro with G2 media supplemented by either hFF or HSA. Our results suggest that hFF as a protein supplement for human in vitro maturation can be replaced by highly defined HSA.

Nuclear and cytoplasmic maturation of in vitro matured human oocytes after temporary nuclear arrest by phosphodiesterase 3-inhibitor

BACKGROUND

The use of hormones for controlled ovarian stimulation results in follicular heterogeneity, with oocytes at diverse stages of nuclear and cytoplasmic development. This study evaluated the impact of temporary nuclear arrest by a specific phosphodiesterase 3-inhibitor (PDE3-I), cilostamide, on nuclear and cytoplasmic maturation of cumulus-free germinal vesicle (GV) human oocytes from controlled ovarian stimulated cycles.

METHODS

GV oocytes (n = 234) were cultured in: (i) medium without the inhibitor (control); (ii) medium supplemented with 1 microM cilostamide and (iii) medium supplemented with 10 microM cilostamide. Oocytes in groups (ii) and (iii) were exposed to cilostamide for 24 h. The PDE3-I was subsequently removed by transfer of oocytes to fresh in vitro maturation (IVM) medium and the reversibility of GV arrest was assessed during IVM culture for maximum 48 h.

RESULTS

Cilostamide (1 and 10 microM) could maintain >80% of the oocytes at the GV stage, without affecting subsequent maturation to metaphase II. Oocytes exposed to 1 microM cilostamide were more likely to have normal bipolar spindles with aligned chromosomes than control oocytes (P < 0.05). When GV chromatin configurations before and after arrest were compared, a significantly higher proportion of oocytes had acquired a nucleolus completely surrounded by a rim of highly condensed chromatin (P < 0.05).

CONCLUSIONS

Temporary nuclear arrest of human GV oocytes with PDE3-I proved to be beneficial for obtaining normal spindle and chromosome configurations after IVM. It resulted also in synchronization within the population of GV oocytes.

In vitro maturation of human oocytes

Immature oocyte retrieval followed by in vitro maturation (IVM) opens a new horizon for modern assisted reproductive technologies (ART). Recent studies in IVM make it a feasible alternative to in vitro fertilization. Antral follicle count is correlated with the pregnancy rate, so women with polycystic ovarian syndrome or polycystic ovaries are the best candidates for IVM. IVM can also be offered to women at risk of ovarian hyperstimulation syndrome or poor responders. From the available information, IVM is a safe procedure and does not increase congenital anomalies or pregnancy complications. Further research is necessary in order to apply this technique to other patients.

First meiosis errors in immature oocytes generated by stimulated cycles

OBJECTIVE

To investigate chromosomal errors detected by first polar body (PB) biopsy in relation to the nuclear maturity of the oocytes.

DESIGN

Retrospective study.

SETTING

Reproductive medicine unit.

PATIENT(S)

Eighty-seven cycles were examined by PB biopsy for aneuploidy. Indications were maternal age >or=38 years (49 cycles), repeated IVF failures (22 cycles), and others (16 cycles).

INTERVENTION(S)

First polar bodies were analyzed for the chromosomes 13, 16, 18, 21, and 22 in both in vivo and in vitro matured oocytes. Euploid oocytes were inseminated by intracytoplasmic sperm injection.

MAIN OUTCOME MEASURE(S)

Chromosomal status of the analyzed oocytes, development after intracytoplasmic sperm injection, pregnancy, and implantation rates.

RESULT(S)

In in vitro matured oocytes, the proportion of chromosomal abnormalities was higher than in in vivo matured oocytes (70% vs. 54%, P<.005), with complex abnormalities being the prevailing defect (62% vs. 40%, P<.001). Conversely, the presence of an extra chromatid or the lack of a chromatid was more frequent in in vivo than in in vitro matured oocytes (55% vs. 34%, P<.001).

CONCLUSION(S)

The low viability of in vitro matured oocytes from stimulated cycles could be related to a significantly higher proportion of chromosomal abnormalities compared with in vivo matured oocytes. Complex abnormalities, involving two or more chromosomes, gave the strongest contribution to the detected increase.

Effect of gonadotrophin stimulation on mouse oocyte quality and subsequent embryonic development in vitro

In-vivo-matured oocytes were collected from naturally ovulated and superovulated [pregnant mare's serum gonadotrophin (PMSG) + human chorionic gonadotrophin (HCG)] mice. Immature oocytes were retrieved from naturally cycling mice and from mice primed with PMSG. The percentages of cleavage and blastocyst formation were significantly different (P < 0.05) between in-vivo- and in-vitro-matured oocytes. Blastocyst formation rate was significantly higher (P < 0.05) in immature oocytes derived from PMSG-primed mice, and the percentages of oocytes with comet tails, and their length, were significantly higher and longer respectively in in-vitro-matured oocytes. Total cell numbers of blastocysts were also significantly different (P < 0.05) between in-vivo- and in-vitro-matured oocytes, but there were also no differences in ratio of trophectoderm (TE)/inner cell mass (ICM). In conclusion, in-vivo-matured mouse oocytes were more competent than those matured in-vitro, perhaps due to a lesser degree of DNA damage. Embryonic development capacity of in-vivo-matured oocytes is not promoted by ovarian stimulation. Gonadotrophin priming prior to immature mouse oocyte retrieval is beneficial to subsequent embryonic development.