Effects of different hyaluronidase concentrations and mechanical procedures for cumulus cell removal on the outcome of intracytoplasmic sperm injection

Automated Denudation of Oocytes

Denudation is a technique for removal of the cumulus cell mass from oocytes in clinical intracytoplasmic sperm injection (ICSI). Manual oocyte denudation requires long training hours and stringent skills, but still suffers from low yield rate and denudation efficiency due to human fatigue and skill variations across operators. To address these limitations, this paper reports a robotic system for automated oocyte denudation. In this system, several key techniques are proposed, including a vision-based contact detection method for measuring the relative z position between the micropipette tip and the dish substrate, recognition of oocytes and the surrounding cumulus cells, automated calibration algorithm for eliminating the misalignment angle, and automated control of the flow rate based on the model of oocyte dynamics during micropipette aspiration and deposition. Experiments on mouse oocytes demonstrated that the robotic denudation system achieved a high yield rate of 97.0 ± 2.8% and denudation efficiency of 95.0 ± 0.8%. Additionally, oocytes denuded by the robotic system showed comparable fertilization rate and developmental competence compared with manual denudation. Our robotic denudation system represents one step towards the automation and standardization of ICSI procedures.

Wedelolactone facilitates the early development of parthenogenetically activated porcine embryos by reducing oxidative stress and inhibiting autophagy

Wedelolactone (WDL) is a coumaryl ether compound extracted from the traditional Chinese medicinal plant, Eclipta prostrata L. It is a natural polyphenol that exhibits a variety of pharmacological activities, such as anti-inflammatory, anti-free radical, and antioxidant activities in the bone, brain, and ovary. However, its effect on embryonic development remains unknown. The present study explored the influence of WDL supplementation of porcine oocytes culture in vitro on embryonic development and the underlying mechanisms and its effect on the levels of Kelch-like ECH-associated protein 1/nuclear factor-erythroid 2-related factor 2/antioxidant response element (Keap1/Nrf2/ARE). The results showed that WDL (2.5 nM) significantly increased the blastocyst formation rate, mitochondrial activity, and proliferation ability while reducing the reactive oxygen species accumulation, apoptosis, and autophagy. These findings suggested that WDL can enhance the growth and development of early porcine embryos to alleviate oxidative stress and autophagy through regulating NRF2 and microtubule-associated protein 1 light chain 3 (MAP1LC3) gene expression levels.

Optimizing embryological aspects of oocyte retrieval, oocyte denudation, and embryo loading for transfer: a state of the art review

Oocyte retrieval, oocyte denudation, and embryo transfer are crucial processes during assisted reproduction (ART). Air quality in the ART laboratory, temperature, pH of the media used and the time interval between oocyte retrieval and insemination are all critical factors. Anesthesia is required for oocyte retrieval, however evidence regarding the potential impact of different methods (general anesthesia, conscious sedation, and local anesthesia) on the clinical outcomes is unclear. The optimal timing of oocyte denudation following retrieval has not been established. Regarding the mechanical denudation process, there is a lack of evidence to demonstrate the safest minimum inner diameter of denuding pipettes used to complete the removal of granulosa cells surrounding the oocytes. During embryo transfer, many clinics worldwide flush the catheter before embryo loading, in an attempt to potentially rinse off any toxic agents; however, there is insufficient evidence to show that flushing the embryo transfer catheter before loading increases the success of ART outcome. Considering the serious gaps in knowledge in ART practice, the aim of this review is to provide an updated overview of the current knowledge regarding the various steps and techniques involved in oocyte retrieval, oocyte denudation, and embryo loading for transfer.

Recombinant versus bovine hyaluronidase for oocyte denudation before intracytoplasmic sperm injection: a systematic review and meta-analysis

The removal of cumulus cells in a process called oocyte denudation is required in order to visualise, grade and manipulate the oocytes before injection. The objective of this study was to appraise critically the published randomised controlled trials (RCTs) comparing recombinant hyaluronidase with bovine hyaluronidase for oocyte denudation before intracytoplasmic sperm injection (ICSI). We performed a comprehensive literature search of the standard medical databases in order to identify the RCTs comparing oocyte denudation with recombinant hyaluronidase or bovine hyaluronidase before ICSI. Three RCTs involving 2445 oocytes collected from 200 women were analysed. There was substantial heterogeneity among the included RCTs. A meta-analysis from the available moderate to high quality trials found no statistical difference in terms of fertilisation rate, embryo quality and live birth rate between the use of recombinant or bovine hyaluronidase for oocyte denudation before ICSI.IMPACT STATEMENTWhat is already known on this subject? The removal of cumulus cells in a process called oocyte denudation is required in order to visualise, grade and manipulate the oocytes before injection. The long-established source of hyaluronidase has been represented by bovine testes, but concern has been raised regarding the possible negative effects over the fragile oocytes by mechanisms involving low enzyme purity, variable concentrations, trauma, prolonged exposure and integration of external DNA in the oocyte. Recombinant human hyaluronidase has been proposed as an alternative in order to counteract the possible negative effects of using animal derived products.What do the results of this study add? A meta-analysis from the available moderate to high quality trials found no statistical difference in fertilisation rate, embryo quality and live birth rate between the use of recombinant or bovine hyaluronidase for oocyte denudation before ICSI.What are the implications of these findings or clinical practice and/or further research? Future trials should be powered adequately in order to be able to identify the possible small differences between the study groups and they should be conducted according to the CONSORT guidelines as the absence of blinding for outcome assessors can induce detection bias.

Toxicity of the recombinant human hyaluronidase ALT-BC4 on embryonic development

Cumulus-oocyte complexes (COCs), which contain immature oocytes, are matured in vitro for in vitro embryo production. Oocyte and cumulus cells are then separated using hyaluronidase. To date, there have only been a few reported cases of the toxic effects of hyaluronidase on porcine oocytes. The aim of this study was to compare the effects of bovine testis-derived hyaluronidase and recombinant human hyaluronidase on oocyte denudation and quality. Porcine COCs were matured for 44 h and denuded using different hyaluronidase concentrations and exposure times. Then, oocytes were activated by electrical parthenogenesis. In experiment 1, COCs were denuded using bovine-derived, ovine-derived (Hirax), and human recombinant (ALT-BC4) hyaluronidases for 10 and 20 min. In experiment 2, bovine-derived and human recombinant (ALT-BC4 and ICSI Cumulase^®) hyaluronidases were used to denude the COCs for 2 and 20 min. In both experiments the oocytes were all completely denuded, and there was no degeneration. Rate of embryo development was significantly increased in group treated ALT-BC4 for 2 min and not significantly different in other treatment groups. In general it slightly decreased with longer exposure times. These results have confirmed that different sources of hyaluronidase do not have detrimental effects on the quality of porcine oocytes and suggest that the human recombinant hyaluronidase ALT-BC4 is suitable for oocyte denudation with an increased blastocyst rate.

Microfluidic Systems for Assisted Reproductive Technologies: Advantages and Potential Applications

Microfluidic technologies have emerged as a powerful tool that can closely replicate the in-vivo physiological conditions of organ systems. Assisted reproductive technology (ART), while being able to achieve successful outcomes, still faces challenges related to technical error, efficiency, cost, and monitoring/assessment. In this review, we provide a brief overview of the uses of microfluidic devices in the culture, maintenance and study of ovarian follicle development for experimental and therapeutic applications. We discuss existing microfluidic platforms for oocyte and sperm selection and maintenance, facilitation of fertilization by in-vitro fertilization/intracytoplastimc sperm injection, and monitoring, selection and maintenance of resulting embryos. Furthermore, we discuss the possibility of future integration of these technologies onto a single platform and the limitations facing the development of these systems. In spite of these challenges, we envision that microfluidic systems will likely evolve and inevitably revolutionize both fundamental, reproductive physiology/toxicology research as well as clinically applicable ART.

Hyaluronidase-based swim-up for semen selection in patients with human papillomavirus semen infection

Infection by human papillomavirus (HPV) represents one of the most common sexually transmitted diseases in both men and women worldwide. Recently, the detection of HPV virions in the semen of a large percentage of sexually active men has been associated with detrimental effects on both sperm parameters and on assisted reproductive technologies (ART) treatment outcomes. Conventional semen washing procedure used in ART have proved to be ineffective in removing HPV bound to sperm, requiring the identification of more effective and specific methods. In the present study, we assessed the possible use of hyaluronidase for the detachment of HPV from sperm cell surface. Semen samples from five normozoospermic control subjects (CTRL) were incubated with HPV virus-like particles (HPV-VLP) and treated with hyaluronidase by both a modified swim-up procedure (M-SU) and single-cell approach (SCA). The treatment with hyaluronidase was associated with the complete loss of HPV-VLP signal on sperms by both M-SU and SCA. In addition, semen samples from 12 HPV-positive infertile patients were treated with hyaluronidase 80 IU/mL by M-SU, resulting in the complete loss of HPV-DNA signal from sperm surface. Finally, the possible impact of hyaluronidase treatment on sperm parameters was assessed on both sperms from the five CTRL subjects and on further five oligo-astheno-terato-zoospermic (OAT) patients, both HPV negative. The treatment with hyaluronidase was equally associated with a slight reduction of sperm viability and progressive motility in both CTRL and OAT. In conclusion, the treatment with hyaluronidase removed efficiently and safely HPV virions bound to spermatozoa.

Thermal stimuli-responsive hyaluronic acid loaded cellulose based physical hydrogel for post-surgical de novo peritoneal adhesion prevention

Effective strategies for post-surgical adhesion prevention have increasingly focused on injectable adhesion barriers due to their minimal invasiveness and wider applicability. In this study, a thermo-reversible hydrogel was developed by combining high molecular weight hyaluronic acid (HA) at various concentrations (0.05, 0.25, and 0.45% w/v) with tempo-oxidized nanocellulose (TOCN), methyl cellulose (MC) and polyethylene glycol (PEG) for anti-adhesion application. The hydrogel preparation time was short and did not require any chemical modification. TOCN ensured the mechanical stability of the hydrogel. MC confirmed thermo-sensitive feature. Higher amounts of HA increased the rate of hydrogel degradation. The HA 0.25 hydrogel was free-flowing, injectable at ambient temperature, capable of faster (40 ± 2 s), and reversible sol-gel (4 °C-37 °C) transition. A rat side-wall cecum abrasion model was used to confirm the complete de novo adhesion prevention efficacy of optimized HA 0.25 hydrogel, where the scratched abdominal wall of animals treated with HA 0.25 hydrogel healed after 14 days. During in vivo experiment, PEG in the hydrogel played a crucial role in adhesion prevention by minimizing friction between the surgical site and nearby organs. In a nutshell, HA 0.25 hydrogel, fabricated without crosslinking agent, is a potential candidate for tissue adhesion prevention strategies.

Expression of adhesion and extracellular matrix genes in human blastocysts upon attachment in a 2D co-culture system

STUDY QUESTION

What are the changes in human embryos, in terms of morphology and gene expression, upon attachment to endometrial epithelial cells?

SUMMARY ANSWER

Apposition and adhesion of human blastocysts to endometrial epithelial cells are predominantly initiated at the embryonic pole and these steps are associated with changes in expression of adhesion and extracellular matrix (ECM) genes in the embryo.

WHAT IS KNOWN ALREADY

Both human and murine embryos have been co-cultured with Ishikawa cells, although embryonic gene expression associated with attachment has not yet been investigated in an in vitro implantation model.

STUDY DESIGN, SIZE, DURATION

Vitrified human blastocysts were warmed and co-cultured for up to 48 h with Ishikawa cells, a model cell line for receptive endometrial epithelium.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Six days post-fertilization (6dpf) human embryos were co-cultured with Ishikawa cells for 12, 24 (7dpf) or 48 h (8dpf) and attachment rate and morphological development investigated. Expression of 84 adhesion and ECM genes was analysed by quantitative PCR. Immunofluorescence microscopy was used to assess the expression of three informative genes at the protein level. Data are reported on 145 human embryos. Mann-Whitney U was used for statistical analysis between two groups, with P < 0.05 considered significant.

MAIN RESULTS AND THE ROLE OF CHANCE

The majority of embryos attached to Ishikawa cells at the level of the polar trophectoderm; 41% of co-cultured embryos were loosely attached after 12 h and 86% firmly attached after 24 h. Outgrowth of hCG-positive embryonic cells at 8dpf indicated differentiation of trophectoderm into invasive syncytiotrophoblast. Gene expression analysis was performed on loosely attached and unattached embryos co-cultured with Ishikawa cells for 12 h. In contrast to unattached embryos, loosely attached embryos expressed THBS1, TNC, COL12A1, CTNND2, ITGA3, ITGAV and LAMA3 and had significantly higher CD44 and TIMP1 transcript levels (P = 0.014 and P = 0.029, respectively). LAMA3, THBS1 and TNC expressions were validated at the protein level in firmly attached 7dpf embryos. Thrombospondin 1 (THBS1) resided in the cytoplasm of embryonic cells whereas laminin subunit alpha 3 (LAMA3) and tenascin C (TNC) were expressed on the cell surface of trophectoderm cells. Incubation with a neutralizing TNC antibody did not affect the rate of embryo attachment or hCG secretion.

LARGE SCALE DATA

None.

LIMITATIONS, REASONS FOR CAUTION

This in vitro study made use of an endometrial adenocarcinoma cell line to mimic receptive luminal epithelium. Also, the number of embryos was limited. Contamination of recovered embryos with Ishikawa cells was unlikely based on their differential gene expression profiles.

WIDER IMPLICATIONS OF THE FINDINGS

Taken together, we provide a 'proof of concept' that initiation of the implantation process coincides with the induction of specific embryonic genes. Genome-wide expression profiling of a larger sample set may provide insights into the molecular embryonic pathways underlying successful or failed implantation.

STUDY FUNDING AND COMPETING INTEREST(S)

A.A. was supported by a grant from the 'Instituut voor Innovatie door Wetenschap en Technologie' (IWT, 121716, Flanders, Belgium). This work was supported by the 'Wetenschappelijk Fonds Willy Gepts' (WFWG G142 and G170, Universitair Ziekenhuis Brussel). The authors declare no conflict of interest.

Application of microfluidic technologies to human assisted reproduction

Microfluidics can be considered both a science and a technology. It is defined as the study of fluid behavior at a sub-microliter level and the investigation into its application to cell biology, chemistry, genetics, molecular biology and medicine. There are at least two characteristics of microfluidics, mechanical and biochemical, which can be influential in the field of mammalian gamete and preimplantation embryo biology. These microfluidic characteristics can assist in basic biological studies on sperm, oocyte and preimplantation embryo structure, function and environment. The mechanical and biochemical characteristics of microfluidics may also have practical and/or technical application(s) to assisted reproductive technologies (ART) in rodents, domestic species, endangered species and humans. This review will consider data in mammals, and when available humans, addressing the potential application(s) of microfluidics to assisted reproduction. There are numerous sequential steps in the clinical assisted reproductive laboratory process that work, yet could be improved. Cause and effect relations of procedural inefficiencies can be difficult to identify and/or remedy. Data will be presented that consider microfluidic applications to sperm isolation, oocyte cumulus complex isolation, oocyte denuding, oocyte mechanical manipulation, conventional insemination, intracytoplasmic sperm injection, embryo culture, embryo analysis and oocyte and embryo cryopreservation. While these studies have progressed in animal models, data with human gametes and embryos are significantly lacking. These data from clinical trials are requisite for making future evidence-based decisions regarding the application of microfluidics in human ART.

Spermatozoa as Functional Components of Robotic Microswimmers

In recent years, the combination of synthetic micro- and nanomaterials with spermatozoa as functional components has led to the development of tubular and helical spermbots - microrobotic devices with potential applications in the biomedical and nanotechnological field. Here, the initial advances in this field are discussed and the use of spermatozoa as functional parts in microdevices elaborated. Besides the potential uses of these hybrid robotic microswimmers, the obstacles along the way are discussed, with suggestions for solutions of the encountered challenges also given.

Low concentration of hyaluronidase for oocyte denudation can improve fertilization rates and embryo quality

Objective

Hyaluronidase enzyme is an extremely important factor for the process of oocyte denudation, but little is known about its negative effects.

Methods

This prospective randomized study analyzed the results of using different concentrations of hyaluronidase (Diluted: 8IU/mL and Normal: 80IU/mL) used for denudation of sibling-oocytes for 22 women undergoing treatment for assisted reproduction by ICSI. A total of 192 oocytes were injected, being 104 for group I (diluted) and 88 for group II (normal). We analyzed fertilization rate, cleavage, embryo quality at 48 and 72 hours and number of transferred embryos in each group.

Results

The diluted enzyme group showed better results in fertilization rates (92.3% vs. 80.6%), mean cleavage (4.18 ± 2.57 vs. 3.09 ± 1.90), in 48-hour embryos A and A + B (60.9% vs. 44.1% and 90.2% vs. 82.3%) and at 72 hours (45.6% vs. 36.8% and 77.1% vs 66.2%), and number of embryos selected for transfer (61.8% vs. 38.1%). The overall pregnancy rate was 59.1%.

Conclusion

This study demonstrates that the use of 8 IU/mL of hyaluronidase, according to the following protocol, is beneficial and can be successfully used for oocyte denudation, and it is also economically advantageous to the laboratory

Cyclin E1 plays a key role in balancing between totipotency and differentiation in human embryonic cells

STUDY HYPOTHESIS

We aimed to investigate if Cyclin E1 (CCNE1) plays a role in human embryogenesis, in particular during the early developmental stages characterized by a short cell cycle.

STUDY FINDING

CCNE1 is expressed in plenipotent human embryonic cells and plays a critical role during hESC derivation via the naïve state and, potentially, normal embryo development.

WHAT IS KNOWN ALREADY

A short cell cycle due to a truncated G1 phase has been associated with the high developmental capacity of embryonic cells. CCNE1 is a critical G1/S transition regulator. CCNE1 overexpression can cause shortening of the cell cycle and it is constitutively expressed in mouse embryonic stem cells and cancer cells.

STUDY DESIGN, SAMPLES/MATERIALS, METHODS

We investigated expression of CCNE1 in human preimplantation embryo development and embryonic stem cells (hESC). Functional studies included CCNE1 overexpression in hESC and CCNE1 downregulation in the outgrowths formed by plated human blastocysts. Analysis was performed by immunocytochemistry and quantitative real-time PCR. Mann-Whitney statistical test was applied.

MAIN RESULTS AND THE ROLE OF CHANCE

The CCNE1 protein was ubiquitously and constitutively expressed in the plenipotent cells of the embryo from the 4-cell stage up to and including the full blastocyst. During blastocyst expansion, CCNE1 was downregulated in the trophectoderm (TE) cells. CCNE1 shortly co-localized with NANOG in the inner cell mass (ICM) of expanding blastocysts, mimicking the situation in naïve hESC. In the ICM of expanded blastocysts, which corresponds with primed hESC, CCNE1 defined a subpopulation of cells different from NANOG/POU5F1-expressing pluripotent epiblast (EPI) cells and GATA4/SOX17-expressing primitive endoderm (PrE) cells. This CCNE1-positive cell population was associated with visceral endoderm based on transthyretin expression and marked the third cell lineage within the ICM, besides EPI and PrE, which had never been described before. We also investigated the role of CCNE1 by plating expanded blastocysts for hESC derivation. As a result, all the cells including TE cells re-gained CCNE1 and, consequently, NANOG expression, resembling the phenotype of naïve hESC. The inhibition of CCNE1 expression with siRNA blocked proliferation and caused degeneration of those plated cells.

LIMITATIONS, REASONS FOR CAUTION

The study is based on a limited number of good-quality human embryos donated to research.

WIDER IMPLICATIONS OF THE FINDINGS

Our study sheds light on the processes underlying the high developmental potential of early human embryonic cells. The CCNE1-positive plenipotent cell type corresponds with a phenotype that enables early human embryos to recover after fragmentation, cryodamage or (single cell) biopsy on day 3 for preimplantation genetic diagnosis. Knowledge on the expression and function of genes responsible for this flexibility will help us to better understand the undifferentiated state in stem cell biology and might enable us to improve technologies in assisted reproduction.

LARGE SCALE DATA

NA STUDY FUNDING AND COMPETING INTERESTS: This research is supported by grants from the Fund for Scientific Research - Flanders (FWO-Vlaanderen), the Methusalem (METH) of the VUB and Scientific Research Fond Willy Gepts of UZ Brussel. There are no competing interests.

A case of conjoined twins after a transfer of a multinuclear embryo

A pregnancy with conjoined twins was observed after transfer of a multinuclear embryo. As nuclear mechanisms have a role in cellular differentiation, association between multinucleation and fetal malformations is possible. Follow-up studies on children born after transfer of embryos with bi/multinuclear blastomeres are needed.

The cumulus cell layer protects the bovine maturing oocyte against fatty acid-induced lipotoxicity

Mobilization of fatty acids from adipose tissue during metabolic stress increases the amount of free fatty acids in blood and follicular fluid and is associated with impaired female fertility. In a previous report, we described the effects of the three predominant fatty acids in follicular fluid (saturated palmitate and stearate and unsaturated oleate) on oocyte maturation and quality. In the current study, the effects of elevated fatty acid levels on cumulus cells were investigated. In a dose-dependent manner, the three fatty acids induced lipid storage in cumulus cells accompanied by an enhanced immune labeling of perilipin-2, a marker for lipid droplets. Lipidomic analysis confirmed incorporation of the administered fatty acids into triglyceride, resulting in a 3- to 6-fold increase of triglyceride content. In addition, palmitate selectively induced ceramide formation, which has been implicated in apoptosis. Indeed, of the three fatty acids tested, palmitate induced reactive oxygen species formation, caspase 3 activation, and mitochondria deterioration, leading to degeneration of the cumulus cell layers. This effect could be mimicked by addition of the ceramide-C2 analog and could be inhibited by the ceramide synthase inhibitor fumonisin-B1. Interfering with the intactness of the cumulus cell layers, either by mechanical force or by palmitate treatment, resulted in enhanced uptake of lipids in the oocyte and increased radical formation. Our results show that cumulus cells act as a barrier, protecting oocytes from in vitro induced lipotoxic effects. We suggest that this protective function of the cumulus cell layers is important for the developmental competence of the oocyte. The relevance of our findings for assisted reproduction technologies is discussed.

CAR expression in human embryos and hESC illustrates its role in pluripotency and tight junctions

Coxsackie virus and adenovirus receptor, CXADR (CAR), is present during embryogenesis and is involved in tissue regeneration, cancer and intercellular adhesion. We investigated the expression of CAR in human preimplantation embryos and embryonic stem cells (hESC) to identify its role in early embryogenesis and differentiation. CAR protein was ubiquitously present during preimplantation development. It was localised in the nucleus of uncommitted cells, from the cleavage stage up to the precursor epiblast, and corresponded with the presence of soluble CXADR3/7 splice variant. CAR was displayed on the membrane, involving in the formation of tight junction at compaction and blastocyst stages in both outer and inner cells, and CAR corresponded with the full-length CAR-containing transmembrane domain. In trophectodermal cells of hatched blastocysts, CAR was reduced in the membrane and concentrated in the nucleus, which correlated with the switch in RNA expression to the CXADR4/7 and CXADR2/7 splice variants. The cells in the outer layer of hESC colonies contained CAR on the membrane and all the cells of the colony had CAR in the nucleus, corresponding with the transmembrane CXADR and CXADR4/7. Upon differentiation of hESC into cells representing the three germ layers and trophoblast lineage, the expression of CXADR was downregulated. We concluded that CXADR is differentially expressed during human preimplantation development. We described various CAR expressions: i) soluble CXADR marking undifferentiated blastomeres; ii) transmembrane CAR related with epithelial-like cell types, such as the trophectoderm (TE) and the outer layer of hESC colonies; and iii) soluble CAR present in TE nuclei after hatching. The functions of these distinct forms remain to be elucidated.

First polar body morphology affects potential development of porcine parthenogenetic embryo in vitro

Previous studies have reported that the first polar body (PB1) morphology reflects embryo development competence, but the effects of PB1 on porcine embryo development remain unknown. This study aims to determine whether the ability of porcine embryo development is related to oocytes' PB1 in vitro. The distribution of type II cortical granules (CGs) of porcine matured oocytes in grade B PB1 is significantly greater compared with those in grades A and C PB1 (71.43% versus 52.46% and 50%; P 0.05). The acetylation level of porcine embryos in the group with grade B PB1 is significantly greater compared with those in the other groups (P < 0.05), and is almost 2.5 times higher than that in grade A. Therefore, porcine oocytes with PB1 in grade B are more competitive in cytoplasmic maturation and further embryo development in vitro.

Conventional IVF as a laboratory strategy to rescue fertility potential in severe poor responder patients: the impact of reproductive aging

OBJECTIVE

To investigate whether laboratory strategies can improve in vitro fertilization (IVF) outcome in poor responder patients. We compared the effectiveness of conventional IVF and intra cytoplasmic sperm injection (ICSI) in assisted reproductive technologies cycles in which only one or two oocytes were retrieved at ovarian pick up, in the absence of male infertility.

DESIGN

Retrospective analysis of 425 cycles in 386 poor responder patients.

INTERVENTION(S)

Standard stimulation protocol with gonadotropins and gonadotropin releasing hormone (GnRH) antagonist.

MAIN OUTCOME MEASURE(S)

Fertilization rate, cleavage rate, good-quality embryo rate, implantation rate, clinical pregnancy rate (PR) and miscarriage rate.

RESULTS

IVF was found to be more advantageous for implantation and PR, especially in patients under 35 years and in women aged between 35 and 38 years. No differences were noted in the other parameter evaluated. Patients aged over 38 years showed no difference using the two techniques.

CONCLUSION

The employment of ICSI in the absence of a male factor can reduce reproductive outcome in poor responder. Probably because of aging-related defects overcoming the advantage of sperm selection, the choice of IVF technique is not relevant to reproductive success when oocyte quality is compromised by reproductive aging. Although further randomized trials are needed to confirm our results, we propose that, in absence of male infertility, conventional IVF might be the technique of choice in young patients, especially in those aged below 35 years.

Percutaneous epididymal sperm aspiration and short time insemination in the treatment of men with obstructive azoospermia

Objective

To study the efficacy of percutaneous epididymal sperm aspiration (PESA) in combination with short time insemination to treat infertile men with obstructive azoospermia (OA).

Design

Paired randomized controlled trial in which each couple’s cohort of oocytes was divided into two equal groups.

Setting

Center for reproductive care.

Patients

Twenty men with OA.

Interventions

Motile spermatozoa were collected using PESA. Half of the oocytes were used for intracytoplasmic sperm injection (ICSI). The rest were inseminated briefly with PESA sperm in vitro fertilization (IVF). After 4–5 h, the remaining cumulus cells were removed mechanically for second polar body observation to decide whether to apply “rescue” ICSI (RE-ICSI).

Main outcome measures

Rates of oocyte maturation, fertilization, cleavage, and good quality embryos. Numbers of available embryos and good quality embryos were compared between PESA-IVF (using a short incubation protocol + rescue ICSI) group and PESA-ICSI group.

Results

In the short time insemination group, cumulus cells were dispersed by PESA spermatozoa. No second polar bodies were found, so RE-ICSI was done. PESA-IVF + RE-ICSI and PESA-ICSI outcomes were comparable in terms of fertilization rates, 2PN cleavage rate and good quality embryo rates with no statistically significant differences.

Conclusions

PESA sperm without centrifugation could disperse the cumulus cells but were infertile and therefore could substitute for synthetic hyaluronidase. The outcomes of PESA-IVF with rescue ICSI were equivalent to PESA-ICSI. Using spermatozoa obtained by PESA and IVF before RE-ICIS is a viable treatment for men with OA.

Does intracytoplasmic morphologically selected sperm injection improve embryo development? A randomized sibling-oocyte study

STUDY QUESTION

Does high-magnification sperm selection influence oocyte fertilization and further embryo development?

SUMMARY ANSWER

The present study did not show a difference in oocyte fertilization rate, nor in embryo development between high-magnification intracytoplasmic morphologically selected sperm injection (IMSI) and conventional ICSI.

WHAT IS KNOWN ALREADY

The presence of nuclear vacuoles in sperm seems to influence embryo development and more specifically blastocyst formation. The use of high magnification for morphological sperm selection prior to ICSI has been associated with higher pregnancy rates and lower miscarriage rates.

STUDY DESIGN, SIZE, DURATION

A prospective sibling-oocyte study was conducted, including 350 ICSI cycles to alleviate male infertility. Cycles were included from March 2010 to November 2011.

PARTICIPANTS/MATERIALS, SETTING, METHODS

On the day of treatment, a high-magnification sperm morphology was assessed on at least 200 spermatozoa. Primary endpoints were oocyte fertilization rate and embryo development. Because embryo transfers were not randomized, the clinical outcome (clinical pregnancy rate per transfer cycle) was descriptive. However, the embryologist selecting the embryos for transfer was blinded for the sperm selection procedure.

MAIN RESULTS AND THE ROLE OF CHANCE

IMSI morphology was assessed in 330 semen samples, resulting in the following distribution: 18.1 ± 14.8% Grade I, 15.2 ± 10.3% Grade II, 12.3 ± 9.1% Grade III and 54.4 ± 23.2% Grade IV. Oocyte fertilization rate was 79.1 and 77.3% after IMSI and ICSI, respectively (NS, paired t-test). Embryo development was similar in both treatment groups up to Day 5 of preimplantation development. Comparable numbers of IMSI-only (n = 125) and ICSI-only (n = 139) embryo transfers were performed. Clinical pregnancies with fetal heart beat were equally distributed over transfers with embryos from IMSI-only (34.4%) or ICSI-only treatment (36.7%).

LIMITATIONS, REASONS FOR CAUTION

The clinical outcome remains descriptive. No firm conclusions could be drawn on cycle rank as a possible indication for IMSI.

WIDER IMPLICATIONS OF THE FINDINGS

The prevalence of vacuoles in normal-shaped spermatozoa is as low as 27.5%. A routine application of IMSI in unselected artificial reproductive technology patients cannot be advocated.

STUDY FUNDING/COMPETING INTEREST(S)

None.

CONCERN: Does ovary need D-chiro-inositol?

BACKGROUND

Polycystic Ovary Syndrome (PCOS) is a multifactorial pathology that affects 10% of the women in reproductive age being the main cause of infertility due to menstrual dysfunction. Since 1980, it is known that PCOS is associated with insulin resistance (IR). The recognition of this association has prompted extensive investigation on the relationship between insulin and gonadal function, and has turned insulin sensitizer agent as the main therapeutic choice. In particular two different polyalcohol myo-inositol and D-chiro-inositol have been shown to improve insulin resistance, hyperandrogenism and to induce ovulation in PCOS women. In particular, while data on myo-inositol and restored ovulation were consistent, data on D-chiro-inositol were not . Recently, a comparative study, proposed a D-chiro-inositol paradox in the ovary of PCOS patients hypothesizing that only myo-inositol has a specific ovarian action. In the present study we aim to further study the role played by D-chiro-inositol at ovarian level.

METHODS

A total of 54 women, aged <40 years and diagnosed with PCOS were enrolled in this study. Patients with insulin resistance and/or hyperglycaemia were excluded from the study. Patients were randomly divided into 5 groups (n=10-12): a placebo group, and 4 groups (A-D) that received 300-600-1200-2400 mg of DCI daily respectively. All treatments were carried out for 8 weeks before follicle stimulating hormone (rFSH) administration.

RESULTS

Total r-FSH units increased significantly in the two groups that received the higher doses of DCI. The number of immature oocytes was significantly increased in the three groups that received the higher doses of DCI. Concurrently, the number of MII oocytes was significantly lower in the D group compared to placebo group. Noteworthy, the number of grade I embryos was significantly reduced by DCI supplementation.

CONCLUSIONS

Indeed, increasing DCI dosage progressively worsens oocyte quality and ovarian response.

Assisting in vitro fertilization by manipulating cumulus-oocyte-complexes either mechanically or enzymatically does not prevent IVF failure

OBJECTIVE

This prospective study was set up in order to analyze whether additional treatment (cutting off supernumerous cumulus cells; adding hyaluronidase) of the cumulus-oocyte-complex (COC) would help to improve treatment outcome.

MATERIAL AND METHODS

COCs from 50 patients were prospectively subdivided into a control group A (no manipulation of COC) and two study groups. In group B, surplus cumulus cells were cut off using syringes, and in the second study group COCs were incubated with a 1:11 dilution of hyaluronidase (final concentration 7 IU/l). Main outcome measures were fertilization rate, embryo development, as well as rates of implantation, pregnancy, and live birth.

RESULTS

Fertilization was higher in group C as compared to the untreated control group A (p<0.05). However, complete fertilization failure could not be avoided by any of the modified IVF approaches. Compaction on day 4 and blastocyst quality on day 5 were significantly improved in group C as compared to group B (but not to group A). Rates of implantation, pregnancy, and live birth were not affected by any of the methods.

CONCLUSION

ICSI seems to be the only choice for avoiding the vast majority of fertilization failures after IVF.

Women with high telomerase activity in luteinised granulosa cells have a higher pregnancy rate during in vitro fertilisation treatment

OBJECTIVE

To study the effect of telomerase activity (TA) in human luteinised granulosa cells (GCs) on the outcome of in vitro fertilisation treatment.

METHODS

Fifty-six women, aged 23 to 39 years, were enrolled and divided into four groups according to their levels of TA.

RESULTS

Seventeen cases in group A exhibited nondetectable TA, 16 cases in group B expressed low levels of TA (between 0.1 and 0.65 OD × mm), 14 cases in group C expressed moderate TA levels (between 0.66 and 1.00 OD × mm) and 9 cases in group D expressed high levels of TA (more than 1.00 OD × mm). The level of total serum testosterone (T) was significantly higher in groups C and D than in group A (1.43±0.10 vs. 1.08±0.11 nmol/L, P<0.030 and 1.56±0.08 vs. 1.08±0.11 nmol/L, P<0.005, respectively). The TA level was positively correlated with T (r=0.291, P<0.011). No obvious differences were observed in rates of fertilisation, cleavage, mature oocyte formation or good-quality embryos among the groups. The patients in group D exhibited the highest rates of embryo implantation and clinical pregnancy (with rates of 52.63% and 77.78%, respectively, compared with 18.92% and 29.41% in group A, 25.71% and 37.50% in group B and 48% and 50% in group C, with P<0.018 and P=0.112, respectively). The patients in group D also had a greater likelihood of becoming pregnant than those in group A (OR: 9.703, P < 0.023), group B (OR: 14.765, P<0.009) or group C (OR: 5.560, P=0.103).

CONCLUSIONS

Luteinised GCs have a certain potential for proliferation and TA of luteinised GCs may predict the clinical outcomes of IVF treatment. Some unknown regulatory mechanisms between TA and T should be studied in further trials.

HLA-G expression in human embryonic stem cells and preimplantation embryos

Human leukocyte Ag-G, a tolerogenic molecule that acts on cells of both innate and adaptive immunity, plays an important role in tumor progression, transplantation, placentation, as well as the protection of the allogeneic fetus from the maternal immune system. We investigated HLA-G mRNA and protein expression in human embryonic stem cells (hESC) derived from the inner cell mass (ICM) of blastocysts. hESC self-renew indefinitely in culture while maintaining pluripotency, providing an unlimited source of cells for therapy. HLA-G mRNA was present in early and late passage hESC, as assessed by real time RT-PCR. Protein expression was demonstrated by flow cytometry, immunocytochemistry, and ELISA on an hESC extract. Binding of HLA-G with its ILT2 receptor demonstrated the functional active status. To verify this finding in a physiologically relevant setting, HLA-G protein expression was investigated during preimplantation development. We demonstrated HLA-G protein expression in oocytes, cleavage stage embryos, and blastocysts, where we find it in trophectoderms but also in ICM cells. During blastocyst development, a downregulation of HLA-G in the ICM cells was present. This data might be important for cell therapy and transplantation because undifferentiated hESC can contaminate the transplant of differentiated stem cells and develop into malignant cancer cells.

Mammalian oocytes are targets for prostaglandin E2 (PGE2) action

BACKGROUND

The ovulatory gonadotropin surge increases synthesis of prostaglandin E2 (PGE2) by the periovulatory follicle. PGE2 actions on granulosa cells are essential for successful ovulation. The aim of the present study is to determine if PGE2 also acts directly at the oocyte to regulate periovulatory events.

METHODS

Oocytes were obtained from monkeys and mice after ovarian follicular stimulation and assessed for PGE2 receptor mRNA and proteins. Oocytes were cultured with vehicle or PGE2 and assessed for cAMP generation, resumption of meiosis, and in vitro fertilization.

RESULTS

Germinal vesicle intact (GV) oocytes from both monkeys and mice expressed mRNA for the PGE2 receptors EP2, EP3, and EP4. EP2 and EP4 proteins were detected by confocal microscopy in oocytes of both species. Monkey and mouse oocytes responded to PGE2 as well as agonists selective for EP2 and EP4 receptors with elevated cAMP, consistent with previous identification of EP2 and EP4 as Gαs/adenylyl cyclase coupled receptors. Incubation of mouse GV stage oocytes with PGE2 delayed oocyte nuclear maturation in vitro, but PGE2 treatment did not alter the percentage of mouse oocytes that fertilized successfully. PGE2 treatment also decreased the percentage of monkey oocytes that resumed meiosis in vitro. In contrast with mouse oocytes, the percentage of monkey oocytes which fertilized in vitro was lower after treatment with PGE2. Monkey oocytes with intact cumulus showed delayed nuclear maturation, but fertilization rate was not affected by PGE2 treatment.

CONCLUSIONS

Monkey and mouse oocytes express functional PGE2 receptors. PGE2 acts directly at mammalian oocytes to delay nuclear maturation. Surrounding cumulus cells modulate the effect of PGE2 to alter subsequent fertilization.

A physiological replacement for polyvinylpyrrolidone (PVP) in assisted reproductive technology

The technique of intracytoplasmic sperm injection (ICSI) requires mechanical immobilization of the sperm that are to be injected; damage thus caused to the sperm membrane is considered to be necessary to activate the sperm for fertilization. Mechanical immobilization and the injection procedure are facilitated by introducing the sperm into a viscous medium that will hinder motility: a solution of polyvinylpyrrolidone (PVP) has been used successfully for this purpose. PVP is an artificial polymer, which has been regarded as chemically inert, although adverse effects have been reported as a result of its use both in vivo and in vitro. Therefore, the use of hyaluronate, the natural component of the extracellular matrix of the cumulus-oocyte complex, was investigated as a replacement for PVP during ICSI. A solution of hyaluronate was found to be as effective as PVP in facilitating the injection procedure, its effect on sperm motility was readily reversible, and its use did not affect the outcome of the treatment cycles in terms of fertilization, pregnancy and live birth rates. Every attempt should be made to eliminate artificial factors in assisted reproductive procedures. Hyaluronate, a natural and readily degradable glycosaminoglycan can be used as a substitute for the artificial PVP polymer without jeopardising the outcome of the treatment cycle.

Human recombinant hyaluronidase (Cumulase) improves intracytoplasmic sperm injection survival and fertilization rates

The cumulus-corona-oocyte complex, composed of cumulus granulosa cells embedded in a matrix of hyaluronan oligosaccharide chains cross-linked by hyaluronan binding proteins and proteoglycans, surrounds each oocyte and must be removed prior to intracytoplasmic sperm injection (ICSI). This is traditionally achieved using enzymatic digestion of the matrix with a bovine-derived hyaluronidase followed by mechanical denudation through pipetting. A human recombinant hyaluronidase (Cumulase) has been developed with the intent of circumventing the problems and concerns associated with the animal origin and lack of purity of the bovine-derived form of the enzyme. In order to compare the effect of Cumulase with that of the bovine enzyme on the rates of normal fertilization and oocyte damage, a retrospective study using four experienced practitioners was performed. In 2006, using Cumulase, a significantly increased rate of normal fertilization (P = 0.0003) and a significantly decreased rate of oocyte damage (P < 0.0001) were observed compared with 2005, during which time bovine-derived hyaluronidase was predominantly used. This study indicates that Cumulase is safe and effective for use in the removal of the cumulus-corona-oocyte complex prior to ICSI, and may have several distinct advantages over the animal-derived form of the enzyme in terms of safety and efficacy.

Randomized sibling-oocyte study using recombinant human hyaluronidase versus bovine-derived Sigma hyaluronidase in ICSI patients

BACKGROUND

The enzyme hyaluronidase from bovine origin is commonly used for oocyte-cumulus cell removal in ICSI. A recombinant human hyaluronidase (rHuPH20) has been introduced as a quality-controlled and safe alternative.

METHODS

In order to validate its effectiveness, a non-inferiority trial was started on sibling cumulus-oocyte complexes (135 ICSI patients). Oocyte denudation involved enzyme incubation under Pasteur pipetting, followed by further mechanical stripping. Primary end-points were oocyte intactness after ICSI and fertilization rate. Secondary end-points were embryo development and positive hCG.

RESULTS

Oocyte intactness after ICSI was 89.6% and 92.9% with rHuPH20 and bovine hyaluronidase, respectively [absolute difference -3.3% (-7.4 to 10.7)]. The fertilization rate was 73.9% after rHuPH20 and 77.1% after bovine hyaluronidase treatment [absolute difference -3.2% (-8.3 to 1.8)]. Embryo development was similar in both treatment groups up till Day 5. Positive hCGs were equally distributed over mixed transfers 21/45 (46.7%) and transfers of only embryos from rHuPH20 treatment 17/35 (48.6%) or transfers of only embryos from bovine hyaluronidase treatment 22/48 (45.8%).

CONCLUSIONS

Our results indicate that rHuPH20 is not inferior to bovine hyaluronidase for oocyte denudation, with regard to oocyte survival and fertilization. rHuPH20 treatment of human oocytes is compatible with good embryo development, with positive hCG results and with live birth.

Correlation between oocyte preincubation time and pregnancy rate after intracytoplasmic sperm injection

BACKGROUND AND AIM

Both nuclear and cytoplasmic maturation of oocytes have to be completed in a coordinated manner to ensure optimal conditions for fertilization. This is well known for in vitro fertilization, but is debated for intracytoplasmic sperm injection (ICSI). It has been reported that preincubation of oocytes prior to ICSI is associated with improved maturation of oocytes, fertilization and embryo quality. Therefore, in the present study, we evaluated the fertilization rate, embryo quality and pregnancy rate in relation to incubation times of metaphase-II oocytes before ICSI.

METHOD

We analyzed 135 selected ICSI cycles. Subjects were assigned to six groups according to oocyte incubation time before ICSI: 2-4 h, 5 h, 6 h, 7 h, 8 h and 9-12 h.

RESULTS

We observed that the fertilization rate increased slightly at short (2 to 6 h) and then decreased at longer preincubation times (7 to 12 h). Concomitantly, cleavage rate increased up to 6 h of preincubation and decreased significantly in the groups in which ICSI was carried out after 7 to 12 h of incubation. With regard to clinical pregnancy rate, we observed a significant increase from 2 to 5 h of preincubation, when this parameter reached its maximum value (35%), tapering to 33% after 6 h and then dropping sharply to 12 h.

CONCLUSIONS

These data confirm that the most appropriate incubation time for mature oocytes before ICSI is 5-6 h. This time improves embryo quality and pregnancy rate in ICSI cycles.

Myo-inositol may improve oocyte quality in intracytoplasmic sperm injection cycles. A prospective, controlled, randomized trial

OBJECTIVE

To determine the effects of myo-inositol on oocyte quality in polycystic ovary syndrome (PCOS) patients undergoing intracytoplasmic sperm injection (ICSI) cycles.

DESIGN

A prospective, controlled, randomized trial.

SETTING

Assisted reproduction centers.

PATIENT(S)

Sixty infertile PCO patients undergoing ovulation induction for ICSI.

INTERVENTION(S)

All participants underwent standard long protocol. Starting on the day of GnRH administration, 30 participants received myo-inositol combined with folic acid (Inofolic) 2 g twice a day and 30 control women received folic acid alone, administrated continuously.

MAIN OUTCOME MEASURE(S)

Primary end points were number of morphologically mature oocytes retrieved, embryo quality, and pregnancy and implantation rates. Secondary end points were total number of days of FSH stimulation, total dose of gonadotropin administered, E(2) level on the day of hCG administration, fertilization rate per number of retrieved oocytes, embryo cleavage rate, live birth and miscarriage rates, cancellation rate, and incidence of moderate or severe ovarian hyperstimulation syndrome.

RESULT(S)

Total r-FSH units (1,958 +/- 695 vs. 2,383 +/- 578) and number of days of stimulation (11.4 +/- 0.9 vs. 12.4 +/- 1.4) were significantly reduced in the myo-inositol group. Furthermore, peak E(2) levels (2,232 +/- 510 vs. 2,713 +/- 595 pg/mL) at hCG administration were significantly lower in patients receiving myo-inositol. The mean number of oocytes retrieved did not differ in the two groups, whereas in the group cotreated with myo-inositol the mean number of germinal vesicles and degenerated oocytes was significantly reduced (1.0 +/- 0.9 vs. 1.6 +/- 1.0), with a trend for increased percentage of oocytes in metaphase II (0.82 +/- 0.11% vs. 0.75 +/- 0.15%).

CONCLUSION(S)

These data show that in patients with PCOS, treatment with myo-inositol and folic acid, but not folic acid alone, reduces germinal vesicles and degenerated oocytes at ovum pick-up without compromising total number of retrieved oocytes. This approach, reducing E(2) levels at hGC administration, could be adopted to decrease the risk of hyperstimulation in such patients.

Sperm surface arylsulfatase A can disperse the cumulus matrix of cumulus oocyte complexes

Cumulus cell layers of expanded cumulus oocyte complexes (COCs) are interlinked with networks of hyaluronic acid, chondroitin sulfate B proteoglycans and link proteins, and they can be dispersed by sperm surface hyaluronidases. In this report, we showed that arylsulfatase A (AS-A), existing on the sperm head surface, also had this dispersion action. Purified AS-A free of protease, hyaluronidase and chondroitinase activities could disperse the cumulus matrix of expanded COCs. However, this COC dispersion action was not associated with AS-A desulfation activity, assayed by using p-nitrocatecholsulfate (artificial substrate). COCs incubated for 1 h with sperm pretreated with anti-AS-A IgG in the presence of apigenin (a hyaluronidase inhibitor) did not exhibit matrix dispersion, whereas several cumulus layers were already dispersed in COCs incubated with sperm pretreated with preimmune IgG. Furthermore, sperm from AS-A null mice showed a significant delay in COC dispersion, compared with wild-type sperm. Within 1 h of sperm-COC co-incubation, the size of COCs incubated with AS-A null sperm was 65% of the original dimension, whereas that of COCs inseminated with wild-type sperm was only 17%. A further delay in COC dispersion by AS-A(-/-) mouse sperm was observed when apigenin was present in the co-incubation. We also showed for the first time that AS-A had a specific affinity for chondroitin sulfate B, a component of cumulus matrix proteoglycan networks; this might provide a mechanism of cumulus matrix destabilization induced by sperm surface AS-A.

Developmental stage on day-5 and fragmentation rate on day-3 can influence the implantation potential of top-quality blastocysts in IVF cycles with single embryo transfer

BACKGROUND

In IVF-ICSI cycles with single embryo transfer (SET), embryo selection for transfer is of crucial importance. The present study aimed to define which embryo parameters might be related to the implantation potential of advanced blastocysts.

METHODS

Overall, in 203 cycles with SET, developmental characteristics of 93 implanted (group A) and 110 non-implanted (group B) advanced blastocysts of good quality were compared. The following developmental parameters were assessed in the two groups: normal fertilization, developmental stage on day 5, number of blastomeres on day 2 and on day 3, fragmentation rate on day 3, compaction on day 4 and cleavage pattern on day 2 and day 3.

RESULTS

Expanded blastocysts compared to full blastocysts have higher implantation potential (56.5% vs. 29.3%, p < 0.05). In group B, a higher proportion of advanced blastocysts showed between 10% and 50% anucleated fragments on day 3 than in group A (23.6 vs 11.8, P = 0.03). Advanced blastocysts with >10-50% fragments on day 3 showed a significant lower implantation (29.7%) than those with < or = 10%fragments (49.4%, P = 0.03). All the other parameters analysed were comparable for the two groups.

CONCLUSION

Developmental stage on day 5 and fragmentation rate on day 3 were related to the implantation potential of advanced blastocysts and should also be taken into account in the selection of the best advanced blastocyst for transfer.

Oocyte cryopreservation: clinical outcome of slow-cooling protocols differing in sucrose concentration

Oocyte cryopreservation represents an important option for management of female fertility, avoiding the ethical concerns associated with embryo storage. This retrospective study evaluated the clinical outcome of two alternative slow freezing protocols involving different sucrose concentrations. From January 2004 to March 2006, spare oocytes from selected couples undergoing IVF or intracytoplasmic sperm injection were frozen using a slow-cooling protocol and thawed at a later stage. Patients were divided into two groups: group A (n = 65), whose oocytes were frozen with propane-1,2-diol (PrOH) and 0.1 mol/l sucrose; and group B (n = 66) whose oocytes were frozen with 0.3 mol/l sucrose. A total of 543 oocytes were thawed in group A and 601 in group B, achieving a survival rate of 24.3 and 71.2% respectively. Whilst fertilization rate (53.5 and 80.4% respectively) was higher in group B, enhanced results for group A were achieved over all (implantation rate per transferred embryos 12.2 versus 5.7%; pregnancy rate per transfer 16.7 versus 9.5%). Normal births and ongoing pregnancies have occurred in both groups. Although in slow-cooling methods higher sucrose concentration in the freezing mixture allows higher post-thaw survival and fertilization rates, overall this did not coincide with an improved clinical outcome.

Comparison of bovine- and recombinant human-derived hyaluronidase with regard to fertilization rates and embryo morphology in a sibling oocyte model: a prospective, blinded, randomized study

The objective of the present study was to compare a traditionally used bovine-derived hyaluronidase (Hyase) with the newly developed recombinant human-derived enzyme product (Cumulase) in intracytoplasmic sperm injection (ICSI) procedures using a sibling oocyte model in a prospective randomized design. The results of the study demonstrate that Cumulase is safe and effective in an ICSI treatment program and can provide comparable if not improved parameters, including fertilization and embryo developmental rates.

Polar body morphology and spindle imaging as predictors of oocyte quality

It has been suggested that first polar body (PBI) morphology reflects oocyte competence. Oocytes with an intact normal-sized PBI have been described as generating better day 2 embryos, higher blastocyst yield, and increased pregnancy and implantation rates. In other studies, PBI morphology was found to be unrelated to fertilization rate, embryo quality, and blastocyst formation. In a prospective analysis, the predictive value of the PBI was investigated by comparing the development of oocytes retrieved from intracytoplasmic sperm injection patients and displaying different PBI morphology, classified according to the following characteristics: normal size and smooth surface (I), fragmented (II), rough surface (III), or large size (IV). Fertilization rates were 59, 57, 64 and 60% respectively. No significant differences were found between the various groups. The proportions of high quality (grade A) day 2 embryos were also comparable among groups I-III (14, 12 and 17% respectively), while the low number of grade A embryos in group IV (two embryos) did not allow comparison with the other classes. These data do not suggest that PBI selection can contribute to identification of embryos with high developmental ability. In order to establish alternative criteria for oocyte selection, a metaphase II (MII) spindle analysis was also conducted via Polscope. In oocytes of patients of different age, spindle retardance (which reflects the high order and density of microtubules) was compared with parameters of embryo development. In aged patients, a trend was observed between low retardance and poor embryo quality, although in general the association between retardance and oocyte developmental performance did not reach statistical significance.

Should diagnostic testicular sperm retrieval followed by cryopreservation for later ICSI be the procedure of choice for all patients with non-obstructive azoospermia?

BACKGROUND

This was a retrospective study to determine if diagnostic testicular biopsy followed by cryopreservation should be the procedure of choice for all patients with testicular failure.

METHODS

The first part of the study analysed 97 ICSI cycles scheduled with frozen-thawed testicular sperm for 69 non-obstructive azoospermia (NOA) patients. The second part focused on a subgroup of 32 patients who underwent 42 ICSI cycles with frozen and 44 cycles with fresh testicular sperm. Sperm characteristics, fertilization, embryo quality, pregnancy and implantation rates were evaluated.

RESULTS

Part I: The average time needed to find sperm was 113 min per cycle and 17 min per individual sperm. Fertilization rate, embryo transfer rate, ongoing pregnancy and implantation rates were 58.4%, 83%, 20.8% and 11.3%, respectively. Part II: The search time per sperm was higher (P=0.016) in frozen (18 min) than in fresh suspensions (13 min). A higher embryo transfer rate was observed in fresh cycles than in frozen cycles (93.2% vs 76.2%, P=0.028). Fertilization, ongoing pregnancy and implantation rates were comparable for the two groups.

CONCLUSIONS

Even in a programme with low-restrictive criteria for patient allocation and for sperm cryopreservation, diagnostic testicular biopsy followed by cryopreservation can be the procedure of choice for patients with testicular failure.

Comparison of transfers to Fallopian tubes or uterus after ICSI

The aim of this study was to compare the implantation rate of tubal-replaced microinjected oocytes (MIFT) versus conventional day 2 intrauterine embryo transfer in patients undergoing intracytoplasmic sperm injection (ICSI). Sixty-three patients in need of ICSI, between 18 and 37 years of age with normal menstrual cycles and fewer than four previous ICSI attempts, were randomized between April 1999 and December 2001. In the MIFT group, up to three micro-injected oocytes were transferred laparoscopically 4 h after microinjection. In the ICSI-embryo transfer group, up to three cleaving embryos were replaced into the uterine cavity 48 h after insemination. Fifty-nine patients reached the stage of oocyte retrieval; 31 patients had a day 2 embryo transfer and 28 patients had MIFT. The ongoing clinical pregnancy and implantation rate (i.e. the total number of gestational sacs with fetal heartbeat divided by the total number of transferred embryos or micro-injected oocytes) was 35 and 24% in the ICSI-embryo transfer group and 29 and 11% in the MIFT group respectively. In conclusion, this study shows a significant decrease in implantation rate in the MIFT group (P < 0.05). In this group of patients there seems to be no advantage to tubal replacement of micro-injected oocytes.

Comparison of sibling oocyte outcomes after intracytoplasmic sperm injection and in vitro fertilization in severe teratozoospermic patients in the first cycle

To follow up the outcome of sibling oocytes subjected to both conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) in the first cycles of severe teratozoospermic patients with normal sperm morphology (NSM)<or=4%, a total of 1193 sibling metaphase II oocytes (MII) in 85 cycles were randomly allocated into two groups: 588 underwent IVF and 605 ICSI and the embryo outcomes between the two groups were compared. The fertilization rate was significantly higher in the ICSI groups than in the IVF group (p < 0.05) and fertilization failure rate in the ICSI group (2.3%) was lower than in the IVF group (28.2%). Subsequently, the rates of embryo arrest as well as grade 1 and 2 embryo formation before day 3, >or=6 cell embryos on day 3 and blastocyst formation on days 5 and 6, did not differ significantly between the two groups. There was a trend towards a high pregnancy rate cycle in mixed ICSI/IVF embryo transfer (ET) (49.1%). In conclusion, this study showed that in couples with only severe teratozoospermia, there was a benefit in subjecting sibling oocytes to both IVF and ICSI in the first cycle because 24 (28.2%) cycles of total fertilization failure were avoided. Furthermore, despite initially significant higher fertilization rates in ICSI than IVF oocytes, subsequent rates of development from >or=6 cells up to blastocyst stage were the same suggesting that ICSI should be used with caution, as after day 3, ICSI-derived embryo development was compromised compared with IVF.

A prospective study on oocyte survival rate after ICSI: influence of injection technique and morphological features

PURPOSE

To determine the influence of technical pitfalls and oocyte morphology on survival rate and cleavage behavior after ICSI.

METHODS

A total of 2210 injection procedures was examined for morphological and technical deviations. Survival rate and cleavage behavior were evaluated.

RESULTS

In 77.8% of all cases ICSI was unsuspicous. Out of 491 deviations from optimal injection deep penetration of the oocyte and abundant presence of cumulus cells showed significant correlation with degeneration rate (p < 0.001). Morphological anomalies associated with the periphery of the oocyte were rather related to degeneration than cytoplasmic anomalies (p < 0.001). Early embryonic development was not impaired by technical or morphological parameters.

CONCLUSIONS

To conclude, these prospective data may be of prognostic value in regard of the number of embryos available for transfer and may help to improve treatment outcome.

The effect of intracytoplasmic sperm injection and semen parameters on blastocyst development in vitro

The present study compares the development and quality of blastocysts derived from conventional oocyte insemination with those derived from intracytoplasmic sperm injection (ICSI). Oocytes were collected from patients undergoing ovarian stimulation with human menopausal gonadotrophins for IVF. Patients with normal semen were assigned to conventional oocyte insemination while those with progressive motility <20% and/or normal sperm morphology < or =4% were assigned to ICSI. Resulting embryos were cultured for up to 6 days. The mean number and percentage of embryos reaching the blastocyst stage and the mean number and percentage of blastocysts of high quality on days 5-6 were assessed for both treatment groups and compared. The influence of paternal factors (sperm concentration, motility, progressive motility, morphology) on blastocyst development and quality were assessed by regression analyses. Significantly more ICSI-derived embryos arrested at the 5- to 8-cell stage (P = 0.024) concomitant with the activation of the paternal genome than those derived from conventional oocyte insemination. Significantly fewer ICSI-derived embryos reached the blastocyst stage on days 5-6 (P<0.001) and significantly fewer ICSI-derived embryos were of high quality (P = 0.002) compared with conventional oocyte insemination. When treatment groups were combined and evaluated by regression analysis, progressive motility and sperm morphology were significantly correlated with diminished blastocyst development and quality (P < 0.05). From these data, we conclude that paternal factors and/or performing ICSI in cases of severe male factor infertility may have a detrimental effect on blastocyst development and their quality.

Preimplantation genetic diagnosis for sickle-cell anemia and for beta-thalassemia

We developed single-cell polymerase chain reaction (PCR) assays for preimplantation genetic diagnosis (PGD) in couples carrying mutations in the beta-globin gene. With PGD the genetic status of an embryo obtained after intracytoplasmic sperm injection (ICSI) is determined by PCR analysis in single blastomeres, allowing only healthy embryos to be transferred to the uterus. We carried out nine PGD cycles using fluorescent PCR for two couples in whom the partners carried sickle-cell trait. Both couples achieved pregnancies, one of which was spontaneously aborted. We have developed two beta-thalassemia PGD protocols: one for the analysis of the 25-26delAA and the IVS2+1G>A mutation, and the other for the simultaneous detection of the IVS1+6T>C and the IVS1+110G>A mutations. For the second protocol, both non-labelled PCR and later fluorescent PCR were used. Both protocols were applied in clinical cycles (two non-labelled PCR cycles and one fluorescent PCR cycle) for two couples. The patient with the fluorescent PCR-PGD cycle became pregnant. Overall, the three fluorescent PCR assays were accurate and reliable with amplification efficiencies of minimum 93% and allele dropout (ADO) rates between 0 and 12%.

Embryo implantation after biopsy of one or two cells from cleavage-stage embryos with a view to preimplantation genetic diagnosis

Preimplantation genetic diagnosis (PGD) can be offered as an alternative to prenatal diagnosis (PND) to couples at risk of having a child with a genetic disease. The affected embryos are detected before implantation by fluorescent in situ hybridisation (FISH) for sexing (X-linked diseases) and chromosomal disorders (numerical and structural) or by polymerase chain reaction (PCR) for monogenic disorders (including some X-linked diseases). The accuracy and reliability of the diagnosis is increased by analysing two blastomeres of the embryo. However, the removal of two blastomeres might have an effect on the implantation capacity of the embryo. We have evaluated the implantation of embryos after the removal of one, two or three cells in 188 PGD cycles where a transfer was done. The patients were divided into five groups: a first group which received only embryos from which one cell had been removed, a second group which received only embryos from which two cells had been removed, a third group which received a mixture of embryos from which one and two cells had been taken, a fourth group where two and three cells had been removed, and a fifth group where three cells had been removed. The overall ongoing pregnancy rate per transfer was 26.1%, the overall implantation rate per transfer was 15.2% and the overall birth rate was 14.2%. Although pregnancy rates between the groups cannot be compared because the second group (two cells removed) contains more rapidly developing and therefore 'better quality' embryos, an ongoing pregnancy rate of 29.1% and an implantation rate of 18.6% per transferred embryo in this group is acceptable, and we therefore advise analysing two cells from a > or =7-cell stage embryo in order to render the diagnosis more accurate and reliable.

Late fertilization of unfertilized human oocytes in in vitro fertilization and intracytoplasmic sperm injection cycles: conventional insemination versus ICSI

PURPOSE

The aim of this study was to evaluate the efficacy of intracytoplasmic sperm injection (ICSI) in comparison with conventional reinsemination using fertilization failed oocytes by conventional in vitro fertilization (IVF).

METHODS

Oocytes were collected from patients of IVF or ICSI cycles. Patients were grouped by fertilization techniques: group 1: conventional IVF; group 2: reinsemination after conventional IVF failure; group 3: regular ICSI; group 4: 1-day-old ICSI after conventional IVF failure; group 5: 2-day-old ICSI after conventional IVF failure; group 6: re-ICSI after regular ICSI failure.

RESULTS

In different insemination groups, normal fertilization rate was higher (P < 0.001) in 1-day-old ICSI (47.1%) and 2-day-old ICSI groups (40.0%) than in reinsemination (14.7%). Abnormal fertilization rate was higher (P < 0.05) in re-ICSI group (21.7%) than any other groups (range: 0-8%). Cleavage rate was higher in 1-day-old (36.7%) and 2-day-old ICSI groups (36.0%) than in reinsemination (5.3%, P < 0.001) or re-ICSI groups (17.4%, P < 0.05). Pregnancy rate was 27.6% and 20.0% in conventional IVF and regular ICSI groups, respectively. However, 1-day-old ICSI (group 4) and 2-day-old ICSI (group 5) were attempted once embryo transfer (ET) but failed pregnancy occurred in each group.

CONCLUSIONS

In fertilization failure cycles, late ICSI increases the rate of fertilization and embryonic development and may rescue the completely failed attempt of pregnancy.