Assessing the Impact of the Novel Sperm Selection Technique 'Annexin-V Coated Polystyrene Bead Technique' on Mouse Assisted Reproductive Techniques Outcomes: Preliminary Findings

ICSI is one of the most commonly used techniques to treat infertility. The sperm selection for the procedure is done 'randomly' by the embryologist according to the motility and morphology parameters which is known not to reflect the potential of a sperm for fertilization, pregnancy and a healthy childbearing. Since the apoptosis rate is higher in sperm cells of infertile patients, it is more likely to choose an apoptotic sperm by the 'random selection method'. We recently introduced a novel sperm selection technique namely 'Annexin-V coated polystrene bead technique'(APB-Tech), for the selection of non-apoptotic sperm cells. The principal of the technique is based on the binding affinity of an apoptotic sperm to 'Annexin-V covered beads' enabling to distinguish a viable and a healthy sperm by light microscopy. The aim of the present study was to observe the effects of this technique on ICSI outcomes in mice. Sibling-oocyte trial was conducted and the outcome measures were compared with the results of traditional sperm selection method. Embryo and blastocyst qualities and blastocyst development rates were significantly increased in APB-Tech group, while the other parameters were not affected. Promising results obtained from the technique reflect its promising potential as a new and powerful tool for sperm selection and thus infertility techniques.

Effect of Two Different Sperm Selection Methods on Boar Sperm Parameters and In Vitro Fertilisation Outcomes

Porcine in vitro embryo production (IVP) protocols have conventionally used density gradient selection (DGS) by centrifugation to prepare sperm samples and achieve successful fertilisation. However, the possible toxicity of the solutions used and the potential damage caused by the centrifugation step may have a negative effect on the quality of the sample. Microfluidic chip-based sperm (MCS) sorting has been proposed as an alternative technique for the selection of high-quality sperm with the purpose of improving reproductive outcomes in IVF. This device does not require centrifugation or any toxic solution to prepare the sample for fertilisation. The sample is not subjected to unnecessary stress, and the process is less operator-dependent. In this study, we compared the sperm parameters of unselected extender-diluted boar semen samples with selected samples using DGS and MCS methods. The results show an expected reduction in sperm concentration after both methods. All the groups were significantly different from one another, with MCS being the group with the lowest concentration. Though the three groups had a similar overall motility, significant differences were found in progressive motility when comparing the unselected group (control, 19.5 ± 1.4%) with DGS and MCS. Progressive motility in DGS was also significantly higher than in MCS (65.2 ± 4.9% and 45.7% ± 5.3, respectively). However, MCS selection resulted in enriched sperm samples with a significantly lower proportion of morphologically abnormal sperm compared to DGS. After fertilisation, no statistical differences were found between the two methods for embryological parameters such as cleavage rates, blastulation rates, and embryo quality. The number of cells in blastocysts derived from MCS was significantly greater than those derived from DGS sperm. Thus, we demonstrate that MCS is at least as good as the standard DGS for most measures. As a more gentle and reproducible approach for sperm selection, however, it could improve consistency and improve IVP outcomes as mediated by a greater proportion of morphologically normal sperm and manifested by a higher cell count in blastocysts.

High sperm deoxyribonucleic acid fragmentation index is associated with an increased risk of preeclampsia following assisted reproduction treatment

OBJECTIVE

To study the association between sperm deoxyribonucleic acid fragmentation index (DFI) and the odds of preeclampsia and other adverse perinatal outcomes after in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) treatment.

DESIGN

A prospective cohort study including infertile couples undergoing conventional IVF or ICSI treatment and their children. Data regarding preeclampsia and perinatal outcomes were derived from the Swedish National Birth Register.

SETTING

University-affiliated fertility clinic.

PATIENT(S)

A total of 1,594 infertile couples undergoing IVF or ICSI treatment and their 1,660 children conceived by assisted reproduction.

INTERVENTION(S)

Sperm DFI measured by Sperm Chromatin Structure Assay.

MAIN OUTCOME MEASURE(S)

The primary outcome was preeclampsia. The secondary outcomes were preterm birth (PTB), low birth weight, low Apgar score, and small for gestational age.

RESULT(S)

With a DFI level of <20% as a reference, the odds ratio (OR) of preeclampsia statistically significantly increased in the group with a DFI level of ≥20% when IVF was used as the fertilization method (OR, 2.2; 95% confidence interval, 1.1-4.4). Already at the DFI levels of ≥10%, in IVF pregnancies, the OR of preeclampsia increased in a dose-response manner, from a prevalence of 3.1% in the reference group to >10% among those with a DFI level of ≥30%. The DFI was not associated with the OR of preeclampsia in the ICSI group. In the entire cohort, a DFI level of ≥20% was associated with an increased OR of PTB (OR, 1.4; 95% confidence interval, 1.0-2.0).

CONCLUSION(S)

High DFI level was associated with increased odds of PTB and, in IVF pregnancies, also increased odds of preeclampsia.

Characterizing the consistency of motion of spermatozoa through nanoscale motion tracing

OBJECTIVE

To demonstrate nanoscale motion tracing of spermatozoa and present analysis of the motion traces to characterize the consistency of motion of spermatozoa as a complement to progressive motility analysis.

DESIGN

Anonymized sperm samples were videographed under a quantitative phase microscope, followed by generating and analyzing superresolution motion traces of individual spermatozoa.

SETTING

Not applicable.

PATIENT(S)

Centrifuged human sperm samples.

INTERVENTION(S)

Not applicable.

MAIN OUTCOME MEASURE(S)

Precision of motion trace of individual sperms, presence of a helical pattern in the motion trace, mean and standard deviations of helical periods and radii of sperm motion traces, speed of progression.

RESULT(S)

Spatially sensitive quantitative phase imaging with a superresolution computational technique MUltiple SIgnal Classification ALgorithm allowed achieving motion precision of 340 nm using ×10, 0.25 numerical aperture lens whereas the diffraction-limited resolution at this setting was 1,320 nm. The motion traces thus derived facilitated new kinematic features of sperm, namely the statistics of helix period and radii per sperm. Through the analysis, 47 sperms with a speed >25 μm/s were randomly selected from the same healthy donor semen sample, it is seen that the kinematic features did not correlate with the speed of the sperms. In addition, it is noted that spermatozoa may experience changes in the periodicity and radius of the helical path over time. Further, some very fast sperms (e.g., >70 μm/s) may demonstrate irregular motion and need further investigation. Presented computational analysis can be used directly for sperm samples from both fertility patients with normal and abnormal sperm cell conditions. We note that MUltiple SIgnal Classification ALgorithm is an image analysis technique that may vaguely fall under the machine learning category, but the conventional metrics for reporting found in Enhancing the QUAlity and Transparency Of health Research network do not apply. Alternative suitable metrics are reported, and bias is avoided through random selection of regions for analysis. Detailed methods are included for reproducibility.

CONCLUSION(S)

Kinematic features derived from nanoscale motion traces of spermatozoa contain information complementary to the speed of the sperms, allowing further distinction among the progressively motile sperms. Some highly progressive spermatozoa may have irregular motion patterns, and whether irregularity of motion indicates poor quality regarding artificial insemination needs further investigation. The presented technique can be generalized for sperm analysis for a variety of fertility conditions.

The impact of microfluidics sperm processing on blastocyst euploidy rates compared with density gradient centrifugation: a sibling oocyte double-blinded prospective randomized clinical trial

OBJECTIVE

To compare the euploidy rates among blastocysts created from sibling oocytes injected with sperm and processed using microfluidics or density gradient centrifugation.

DESIGN

Sibling oocyte randomized controlled trial.

SETTING

Single university-affiliated infertility practice.

PATIENTS

A total of 106 patients aged 18-42 years undergoing fresh in vitro fertilization treatment cycles with preimplantation genetic testing between January 2021 and April 2022 contributed 1,442 mature oocytes, which were injected with sperm and processed using microfluidics or density gradient centrifugation.

INTERVENTION(S)

The sperm sample is divided and processed using a microfluidics device and density gradient centrifugation for injection into sibling oocytes.

MAIN OUTCOME MEASURE(S)

The primary outcome was the embryo euploidy rate. Secondary outcomes included fertilization, high-quality blastulation, and ongoing pregnancy rates.

RESULT(S)

The blastocyst euploidy rate per mature oocyte was not significantly different in the study group compared with the control group (22.9% vs. 20.5%). The blastocyst euploidy rate per biopsied embryo was also similar between the 2 groups (53.0% vs. 45.7%). However, the fertilization rate per mature oocyte injected was found to be significantly higher in the study group compared with the control group (76.0% vs. 69.9%). The high-quality blastulation rate per mature oocyte injected was similar between the 2 groups, as was the total number of embryos frozen. There were no differences in the number of participants with no blastocysts for biopsy or the number of participants with no euploid embryos between the 2 groups. Among the male factor infertility and recurrent pregnancy loss subgroups, there were no differences in euploidy rates, fertilization rates, blastulation rates, or total numbers of blastocysts frozen, although the study was underpowered to detect these differences. Seventy-seven patients underwent frozen embryo transfer; there were no significant differences in pregnancy outcomes between the 2 groups.

CONCLUSION(S)

Microfluidics processing did not improve embryo euploidy rates compared with density gradient centrifugation in this sibling oocyte study, although fertilization rates were significantly higher.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04744025.

Emerging trends in sperm selection: enhancing success rates in assisted reproduction

This comprehensive review explores the evolving landscape of sperm selection techniques within the realm of Assisted Reproductive Technology (ART). Our analysis delves into a range of methods from traditional approaches like density gradient centrifugation to advanced techniques such as Magnetic-Activated Cell Sorting (MACS) and Intracytoplasmic Morphologically Selected Sperm Injection (IMSI). We critically assess the efficacy of these methods in terms of sperm motility, morphology, DNA integrity, and other functional attributes, providing a detailed comparison of their clinical outcomes. We highlight the transition from conventional sperm selection methods, which primarily focus on physical characteristics, to more sophisticated techniques that offer a comprehensive evaluation of sperm molecular properties. This shift not only promises enhanced prediction of fertilization success but also has significant implications for improving embryo quality and increasing the chances of live birth. By synthesizing various studies and research papers, we present an in-depth analysis of the predictability of different sperm selection procedures in ART. The review also discusses the clinical applicability of these methods, emphasizing their potential in shaping the future of assisted reproduction. Our findings suggest that the integration of advanced sperm selection strategies in ART could lead to more cost-effective treatments with reduced duration and higher success rates. This review aims to provide clinicians and researchers in reproductive medicine with comprehensive insights into the current state and future prospects of sperm selection technologies in ART.

Sperm Preparation with Microfluidic Sperm Sorting Chip May Improve Intracytoplasmic Sperm Injection Outcomes Compared to Density Gradient Centrifugation

Does sperm preparation using the FERTILE PLUS™ Sperm Sorting Chip improve fertilization rates, blastocyst formation, utilization, and euploidy rates in patients undergoing intracytoplasmic sperm injection (ICSI), compared with density gradient centrifugation (DGC)? A single-cohort, retrospective data review including data from 53 couples who underwent ICSI cycles within a 12-month period. For each couple, the two closest, consecutive cycles were identified, where one used the standard technique of sperm preparation (DGC) and the subsequent used FERTILE PLUS™, therefore, couples acted as their own controls. Paired samples t-test was used to compare means for the outcomes (fertilization, blastocyst formation, utilization, and euploidy rates). Binary logistic regression analysis assessed the relationship between female age, the presence of male factor infertility, and euploidy rates. Blastocyst, utilization, and euploidy rates were significantly higher for cycles using FERTILE PLUS™ compared to DGC (76% vs 56%, p = 0.002; 60% vs 41%, p = 0.005, and 40% vs 20%, p = 0.001, respectively). Although there was an increase in fertilization rates for cycles using FERTILE PLUS™, this was not significant (72% vs 68%, p = 0.449). The euploidy rates of females ≤ 35 years were significantly increased when the FERTILE PLUS™ sperm preparation method was used, compared to the older age group (OR 2.31, p = 0.007). No significant association was found between the presence or absence of male factor infertility and euploidy rates between the two cycles. This study provides tentative evidence that the FERTILE PLUS™ microfluidic sorting device for sperm selection can improve blastocyst formation, utilization, and euploidy rates following ICSI in comparison to the DGC method.

Automated Single-Sperm Selection Software (SiD) during ICSI: A Prospective Sibling Oocyte Evaluation

The computer-assisted program SiD was developed to assess and select sperm in real time based on motility characteristics. To date, there are limited studies examining the correlation between AI-assisted sperm selection and ICSI outcomes. To address this limit, a total of 646 sibling MII oocytes were randomly divided into two groups as follows: the ICSI group (n = 320): ICSI performed with sperm selected by the embryologist and the ICSI-SiD group (n = 326): ICSI performed with sperm selected using SiD software. Our results show a non-significant trend towards improved outcomes in the ICSI-SiD group across various biological parameters, including fertilization, cleavage, day 3 embryo development, blastocyst development, and quality on day 5. Similarly, we observed a non-significant increase in these outcomes when comparing both groups with sperm selection performed by a junior embryologist. Embryo development was monitored using a timelapse system. Some fertilization events happen significantly earlier when SiD is used for ICSI, but no significant difference was observed in the ICSI-SiD group for other timepoints. We observed comparable cumulative early and clinical pregnancy rates after ICSI-SiD. This preliminary investigation illustrated that employing the automated sperm selection software SiD leads to comparable biological outcomes, suggesting its efficacy in sperm selection.

Does microfluidic sperm selection improve clinical pregnancy and miscarriage outcomes in assisted reproductive treatments? A systematic review and meta-analysis

BACKGROUND

The microfluidic sperm selection (MFSS) device has emerged as a promising adjunct in assisted reproduction treatments (ART). It employs mechanisms of biomimicry based on the microanatomy of the female reproductive tract through strategies like chemotaxis and rheotaxis. Numerous studies assert improvements in ART outcomes with the use of MFSS, often attributed to the theoretical reduction in sperm DNA damage compared to other techniques. However, these attributed benefits lack validation through large-scale clinical trials, and there is no significant evidence of enhanced assisted reproductive treatments (ART) outcomes.

OBJECTIVE

To evaluate whether the utilization of MFSS enhances clinical pregnancy results and abortion outcomes in couples undergoing ART compared to standard sperm selection techniques for Intracytoplasmic Sperm Injection (ICSI). We also assessed laboratory outcomes as a supplementary analysis.

SEARCH METHODS

We conducted searches across databases including PubMed, NIH, LILACS, CENTRAL, Crossref, Scopus, and OpenAlex. A total of 1,255 records were identified. From these, 284 duplicate records were eliminated, and an additional 895 records were excluded due to their association with patent applications, diagnostic tests, forensic analyses, or irrelevance to the research focus. Among the initially eligible 76 studies, 63 were excluded, encompassing abstracts, studies lacking adequate control groups, and ongoing clinical trials. Ultimately, 13 studies were selected for inclusion in the ensuing meta-analysis.

RESULTS

Regarding clinical pregnancy, we assessed a total of 868 instances of clinical pregnancies out of 1,646 embryo transfers. Regarding miscarriage, we examined 95 cases of pregnancy loss among the 598 confirmed clinical pregnancies in these studies.

CONCLUSION

The utilization of MFSS demonstrates marginal positive outcomes compared to standard sperm selection techniques, without statistical significance in any of the analyses.

BROADER IMPLICATIONS

This study conducted the first meta-analysis to evaluate clinical pregnancy rates, miscarriage rates, and laboratory results associated with the use of MFSS compared to standard sperm selection techniques. We have also listed potentially eligible studies for future inclusion. It's important to emphasize the need for multicenter studies with standardized parameters to attain a more robust clarification of this issue.

Good practice recommendations on add-ons in reproductive medicine†

STUDY QUESTION

Which add-ons are safe and effective to be used in ART treatment?

SUMMARY ANSWER

Forty-two recommendations were formulated on the use of add-ons in the diagnosis of fertility problems, the IVF laboratory and clinical management of IVF treatment.

WHAT IS KNOWN ALREADY

The innovative nature of ART combined with the extremely high motivation of the patients has opened the door to the wide application of what has become known as 'add-ons' in reproductive medicine. These supplementary options are available to patients in addition to standard fertility procedures, typically incurring an additional cost. A diverse array of supplementary options is made available, encompassing tests, drugs, equipment, complementary or alternative therapies, laboratory procedures, and surgical interventions. These options share the common aim of stating to enhance pregnancy or live birth rates, mitigate the risk of miscarriage, or expedite the time to achieving pregnancy.

STUDY DESIGN, SIZE, DURATION

ESHRE aimed to develop clinically relevant and evidence-based recommendations focusing on the safety and efficacy of add-ons currently used in fertility procedures in order to improve the quality of care for patients with infertility.

PARTICIPANTS/MATERIALS, SETTING, METHODS

ESHRE appointed a European multidisciplinary working group consisting of practising clinicians, embryologists, and researchers who have demonstrated leadership and expertise in the care and research of infertility. Patient representatives were included in the working group. To ensure that the guidelines are evidence-based, the literature identified from a systematic search was reviewed and critically appraised. In the absence of any clear scientific evidence, recommendations were based on the professional experience and consensus of the working group. The guidelines are thus based on the best available evidence and expert agreement. Prior to publication, the guidelines were reviewed by 46 independent international reviewers. A total of 272 comments were received and incorporated where relevant.

MAIN RESULTS AND THE ROLE OF CHANCE

The multidisciplinary working group formulated 42 recommendations in three sections; diagnosis and diagnostic tests, laboratory tests and interventions, and clinical management.

LIMITATIONS, REASONS FOR CAUTION

Of the 42 recommendations, none could be based on high-quality evidence and only four could be based on moderate-quality evidence, implicating that 95% of the recommendations are supported only by low-quality randomized controlled trials, observational data, professional experience, or consensus of the development group.

WIDER IMPLICATIONS OF THE FINDINGS

These guidelines offer valuable direction for healthcare professionals who are responsible for the care of patients undergoing ART treatment for infertility. Their purpose is to promote safe and effective ART treatment, enabling patients to make informed decisions based on realistic expectations. The guidelines aim to ensure that patients are fully informed about the various treatment options available to them and the likelihood of any additional treatment or test to improve the chance of achieving a live birth.

STUDY FUNDING/COMPETING INTEREST(S)

All costs relating to the development process were covered from ESHRE funds. There was no external funding of the development process or manuscript production. K.L. reports speakers fees from Merck and was part of a research study by Vitrolife (unpaid). T.E. reports consulting fees from Gynemed, speakers fees from Gynemed and is part of the scientific advisory board of Hamilton Thorne. N.P.P. reports grants from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare, speakers fees from Merck Serono, Ferring Pharmaceutical, Theramex, Gedeon Richter, Organon, Roche, IBSA and Besins Healthcare. S.R.H. declares being managing director of Fertility Europe, a not-for-profit organization receiving financial support from ESHRE. I.S. is a scientific advisor for and has stock options from Alife Health, is co-founder of IVFvision LTD (unpaid) and received speakers' fee from the 2023 ART Young Leader Prestige workshop in China. A.P. reports grants from Gedeon Richter, Ferring Pharmaceuticals and Merck A/S, consulting fees from Preglem, Novo Nordisk, Ferring Pharmaceuticals, Gedeon Richter, Cryos and Merck A/S, speakers fees from Gedeon Richter, Ferring Pharmaceuticals, Merck A/S, Theramex and Organon, travel fees from Gedeon Richter. The other authors disclosed no conflicts of interest.

DISCLAIMER

This Good Practice Recommendations (GPRs) document represents the views of ESHRE, which are the result of consensus between the relevant ESHRE stakeholders and are based on the scientific evidence available at the time of preparation.ESHRE GPRs should be used for information and educational purposes. They should not be interpreted as setting a standard of care or bedeemedinclusive of all proper methods of care, or be exclusive of other methods of care reasonably directed to obtaining the same results.Theydo not replace the need for application of clinical judgement to each individual presentation, or variations based on locality and facility type.Furthermore, ESHRE GPRs do not constitute or imply the endorsement, or favouring, of any of the included technologies by ESHRE.

Spermatozoa isolation with Felix™ outperforms conventional density gradient centrifugation preparation in selecting cells with low DNA damage

BACKGROUND

The optimization of spermatozoa preparation techniques in order to obtain cell fractions enriched with structurally and functionally "superior" spermatozoa is a key objective of the assisted reproduction industry.

OBJECTIVES

The purpose of this study was to evaluate a recent development of an electrophoretic spermatozoa separation device (Felix™, Memphasys Ltd, Sydney, Australia) and to compare its performance with conventional spermatozoa preparation by density gradient centrifugation (DGC). Particular attention was paid to the evaluation of sperm DNA/nuclear integrity.

MATERIALS & METHODS

A cohort of 29 human semen samples was studied. Semen samples were analyzed fresh and after DGC or Felix™ preparation. Semen parameters monitored included sample volume, sperm count, total motility, progressive motility, sperm DNA fragmentation using the Sperm Chromatin Structure Assay and sperm DNA oxidation.

RESULTS

Spermatozoa preparation with Felix™ resulted in significantly improved spermatozoa fractions with higher progressive motility, lower sperm DNA fragmentation, and lower sperm DNA oxidation compared with raw semen and DGC-prepared spermatozoa.

DISCUSSION & CONCLUSION

The data collected in this study support the preparation of spermatozoa by the Felix™ system as it allows selection of spermatozoa with the highest progressive motility as well as the lowest nuclear/DNA damage. These improved sperm parameters, along with the fact that the Felix™ separation process is very fast and highly standardized, should be of great interest to the assisted reproduction technologies industry.

Age-Dependent Alterations in Semen Parameters and Human Sperm MicroRNA Profile

The trend to delay parenthood is increasing, impacting fertility and reproductive outcomes. Advanced paternal age (APA), defined as men's age above 40 years at conception, has been linked with testicular impairment, abnormal semen parameters, and poor reproductive and birth outcomes. Recently, the significance of sperm microRNA for fertilization and embryonic development has emerged. This work aimed to investigate the effects of men's age on semen parameters and sperm microRNA profiles. The ejaculates of 333 Portuguese men were collected between 2018 and 2022, analyzed according to WHO guidelines, and a density gradient sperm selection was performed. For microRNA expression analysis, 16 normozoospermic human sperm samples were selected and divided into four age groups: ≤30, 31-35, 36-40, and >40 years. microRNA target genes were retrieved from the miRDB and TargetScan databases and Gene Ontology analysis was performed using the DAVID tool. No significant correlation was found between male age and conventional semen parameters, except for volume. Fifteen differentially expressed microRNAs (DEMs) between groups were identified. Enrichment analysis suggested the involvement of DEMs in the sperm of men with advanced age in critical biological processes like embryonic development, morphogenesis, and male gonad development. Targets of DEMs were involved in signaling pathways previously associated with the ageing process, including cellular senescence, autophagy, insulin, and mTOR pathways. These results suggest that although conventional semen parameters were not affected by men's age, alterations in microRNA regulation may occur and be responsible for poor fertility and reproductive outcomes associated with APA.

Stain-Free Sperm Analysis and Selection for Intracytoplasmic Sperm Injection Complying with WHO Strict Normal Criteria

This multi-center study evaluated a novel microscope system capable of quantitative phase microscopy (QPM) for label-free sperm-cell selection for intracytoplasmic sperm injection (ICSI). Seventy-three patients were enrolled in four in vitro fertilization (IVF) units, where senior embryologists were asked to select 11 apparently normal and 11 overtly abnormal sperm cells, in accordance with current clinical practice, using a micromanipulator and 60× bright field microscopy. Following sperm selection and imaging via QPM, the individual sperm cell was chemically stained per World Health Organization (WHO) 2021 protocols and imaged via bright field microscopy for subsequent manual measurements by embryologists who were blinded to the QPM measurements. A comparison of the two modalities resulted in mean differences of 0.18 µm (CI -0.442-0.808 µm, 95%, STD-0.32 µm) for head length, -0.26 µm (CI -0.86-0.33 µm, 95%, STD-0.29 µm) for head width, 0.17 (CI -0.12-0.478, 95%, STD-0.15) for length-width ratio and 5.7 for acrosome-head area ratio (CI -12.81-24.33, 95%, STD-9.6). The repeatability of the measurements was significantly higher in the QPM modality. Surprisingly, only 19% of the subjectively pre-selected normal cells were found to be normal according to the WHO2021 criteria. The measurements of cells imaged stain-free through QPM were found to be in good agreement with the measurements performed on the reference method of stained cells imaged through bright field microscopy. QPM is non-toxic and non-invasive and can improve the clinical effectiveness of ICSI by choosing sperm cells that meet the strict criteria of the WHO2021.

Strategies for Bacterial Eradication from Human and Animal Semen Samples: Current Options and Future Alternatives

The primary role of semen processing and preservation is to maintain a high proportion of structurally and functionally competent and mature spermatozoa, that may be used for the purposes of artificial reproduction when needed, whilst minimizing any potential causes of sperm deterioration during ex vivo semen handling. Out of a multitude of variables determining the success of sperm preservation, bacterial contamination has been acknowledged with an increased interest because of its often unpredictable and complex effects on semen quality. Whilst antibiotics are usually the most straight-forward option to prevent the bacterial contamination of semen, antimicrobial resistance has become a serious threat requiring widespread attention. As such, besides discussing the consequences of bacteriospermia on the sperm vitality and the risks of antibiotic overuse in andrology, this paper summarizes the currently available evidence on alternative strategies to prevent bacterial contamination of semen prior to, during, and following sperm processing, selection, and preservation. Alternative antibacterial supplements are reviewed, and emphasis is given to modern methods of sperm selection that may be combined by the physical removal of bacteria prior to sperm preservation or by use in assisted reproductive technologies.

The use of ICSI in ART: evidence for practice

This article reviews the evidence regarding the safety and efficacy of intra-cytoplasmic sperm injection (ICSI). It provides evidence-based clinical and laboratory guidelines and recommendations for use of ICSI within an assisted reproductive technology (ART) service. The guidelines address the evidence for the use of ICSI rather than conventional IVF (cIVF); the use of ART techniques supplementary to ICSI; and risks associated with ICSI. This article is not intended to be the only approved standard of practice or to dictate an exclusive course of treatment. Other plans of management may be appropriate, taking into account the needs and medical history of the patient, available resources, and institutional or clinical practice limitations.

Sperm selection by the oviduct: perspectives for male fertility and assisted reproductive technologies†

The contribution of sperm to embryogenesis is gaining attention with up to 50% of infertility cases being attributed to a paternal factor. The traditional methods used in assisted reproductive technologies for selecting and assessing sperm quality are mainly based on motility and viability parameters. However, other sperm characteristics, including deoxyribonucleic acid integrity, have major consequences for successful live birth. In natural reproduction, sperm navigate the male and female reproductive tract to reach and fertilize the egg. During transport, sperm encounter many obstacles that dramatically reduce the number arriving at the fertilization site. In humans, the number of sperm is reduced from tens of millions in the ejaculate to hundreds in the Fallopian tube (oviduct). Whether this sperm population has higher fertilization potential is not fully understood, but several studies in animals indicate that many defective sperm do not advance to the site of fertilization. Moreover, the oviduct plays a key role in fertility by modulating sperm transport, viability, and maturation, providing sperm that are ready to fertilize at the appropriate time. Here we present evidence of sperm selection by the oviduct with emphasis on the mechanisms of selection and the sperm characteristics selected. Considering the sperm parameters that are essential for healthy embryonic development, we discuss the use of novel in vitro sperm selection methods that mimic physiological conditions. We propose that insight gained from understanding how the oviduct selects sperm can be translated to assisted reproductive technologies to yield high fertilization, embryonic development, and pregnancy rates.

Molecular Chaperone HSPA2 Distribution During Hyaluronic Acid Selection in Human Sperm

During fertilization, sperm hyaluronidase activity is essential for spermatozoa to successfully penetrate the hyaluronic acid-enriched extracellular matrix of the cumulus cells. Since molecular chaperones, as the heat shock protein A2, are typically involved in bringing hyaluronic acid receptors to the cell surface, here we evaluated the presence and spatial location of HSPA2 on human spermatozoa based on its hyaluronic acid binding capacity. This study included 16 normozoospermic sperm samples from volunteering donors. The location of HSPA2 was studied in cells before and after 1-h incubation under capacitating conditions, as well as in spermatozoa selected according to their ability of binding to hyaluronic acid. Our results showed no significant differences in HSPA2 immunofluorescent cells before and after 1 h of incubation in capacitating conditions. Nevertheless, after hyaluronic acid selection, the percentage of HSPA2-labelled cells increased significantly, indicating that the interaction with hyaluronic acid may induce the unmasking of HSPA2 epitopes. Furthermore, after swim-up and hyaluronic acid selection, spermatozoa presented a highly immunostained equatorial band with a homogeneous fluorescence throughout the acrosomal region. This distribution has been previously suggested to have important implications in male fertility. Noteworthy, a homogeneous fluorescence among the acrosomal region with a more intense labelling at the apical region was observed only in hyaluronic acid bound sperm cells, which may be associated with primary gamete recognition. Our findings suggest that the hyaluronic acid selection technique and HSPA2 biomarker should be considered candidates to complement the classic seminal analysis before recommending an appropriate assisted reproduction technique.

Double strand DNA breaks in sperm: the bad guy in the crowd

PURPOSE

The main objective of this opinion paper was to bring to light and enhance our understanding of the amount of double-strand DNA breaks in sperm and whether there is a threshold of no return when considering repair by the oocyte/embryo.

METHODS

A brief review of literature related to the theories proposed for the appearance of double-strand breaks in human spermatozoa. Further commentary regarding their detection, how oocytes or embryos may deal with them, and what are the consequences if they are not repaired. Finally, a strategy for dealing with patients who have higher levels of double-strand DNA breaks in sperm is proposed by reviewing and presenting data using testicular extracted sperm.

RESULTS

We propose a theory that a threshold may exist in the oocyte that allows either complete or partial DNA repair of impaired sperm. The closer that an embryo is exposed to the threshold, the more the effect on the ensuing embryo will fail to reach various milestones, including blastocyst stage, implantation, pregnancy loss, an adverse delivery outcome, or offspring health. We also present a summary of the role that testicular sperm extraction may play in improving outcomes for couples in which the male has a high double-strand DNA break level in his sperm.

CONCLUSIONS

Double-strand DNA breaks in sperm provide a greater stress on repair mechanisms and challenge the threshold of repair in oocytes. It is therefore imperative that we improve our understanding and diagnostic ability of sperm DNA, and in particular, how double-strand DNA breaks originate and how an oocyte or embryo is able to deal with them.

The role of spermatozoa-zona pellucida interaction in selecting fertilization-competent spermatozoa in humans

Human fertilization begins when a capacitated spermatozoon binds to the zona pellucida (ZP) surrounding a mature oocyte. Defective spermatozoa-ZP interaction contributes to male infertility and is a leading cause of reduced fertilization rates in assisted reproduction treatments (ARTs). Human ejaculate contains millions of spermatozoa with varying degrees of fertilization potential and genetic quality, of which only thousands of motile spermatozoa can bind to the ZP at the fertilization site. This observation suggests that human ZP selectively interacts with competitively superior spermatozoa characterized by high fertilizing capability and genetic integrity. However, direct evidence for ZP-mediated sperm selection process is lacking. This study aims to demonstrate that spermatozoa-ZP interaction represents a crucial step in selecting fertilization-competent spermatozoa in humans. ZP-bound and unbound spermatozoa were respectively collected by a spermatozoa-ZP coincubation assay. The time-course data demonstrated that ZP interacted with a small proportion of motile spermatozoa. Heat shock 70 kDa protein 2 (HSPA2) and sperm acrosome associated 3 (SPACA 3) are two protein markers associated with the sperm ZP-binding ability. Immunofluorescent staining indicated that the ZP-bound spermatozoa had significantly higher expression levels of HSPA2 and SPACA3 than the unbound spermatozoa. ZP-bound spermatozoa had a significantly higher level of normal morphology, DNA integrity, chromatin integrity, protamination and global methylation when compared to the unbound spermatozoa. The results validated the possibility of applying spermatozoa-ZP interaction to select fertilization-competent spermatozoa in ART. This highly selective interaction might also provide diagnostic information regarding the fertilization potential and genetic qualities of spermatozoa independent of those derived from the standard semen analysis.

Sperm selection with Annexin-V coated polystrene bead technique (APB-Tech): A novel and reliable method for the microscopic selection of viable and non-apoptotic sperm to be used for intracytoplasmic sperm injection

Infertility is a growing health problem that affects 20% of couples who want to conceive. 'Intracytoplasmic sperm injection' (ICSI) is a commonly used assisted reproduction treatment technique that offers the couples to overcome a wide variety of infertility reasons, including female, male and unexplained infertility. A crucial step in ICSI is choosing the correct sperm with the highest potential to form a healthy embryo and thus a healthy offspring. The sperm selection strategies aim to obtain a sperm population with better motility and morphology, which are insufficient to predict a sperm's reproductive potential. The elimination of apoptotic sperms, which is shown to be higher in infertile males and which is shown to affect embryo development and reproductive cohort significantly should also be included in the selection strategies. Among all sperm selection methods, there are only a few which can eliminate apoptotic sperm, but because they need extra types of equipments, a long training period, and high costs, they couldn't find place in the most commonly used techniques in an IVF lab. Selecting the non-apoptotic sperm cells will help us choose a sperm that is more likely to be chosen by the natural selection mechanisms and thus will help to mimic the natural conception more. The study aimed to develop a novel, easy and a harmless individual sperm selection technique to enable choosing non-apoptotic viable sperm cells via light microscopy without any need for extra equipment, education and cost to be used for ''ICSI'. The technique is based on the binding ability of Annexin-V covered polystrene beads to the externalized phosphatidylserine at the outer leaflet of an apoptotic sperm's plasma membrane. After Annexin-V covered polystyrene beads were prepared, beads obtained were attached to BALB-c mice sperm, and the technique is optimized to obtain the most efficient attachment conditions. The results are then compared with the results of four well-known reliable apoptosis detection techniques to test the validity and sperm survival test to test the toxicity of the technique. The method is proven to be '''reliable' by comparing it with the results of well-known techniques, including TUNEL and SCSA (sperm chromatin structure assay), and '''safe' by showing its non-toxicity via sperm survival test (SST). In addition, the method enables the selection of sperm cells more closer to naturally-chosen ones from a pool of sperm that should not be allowed to be randomly chosen during microinjection. To date, it was impossible to distinguish a non-apoptotic sperm without harming it or without needing additional equipment other than a routine IVF lab and extra training other than routine andrology work. The technique is named as 'Annexin-V coated polystyrene bead technique (APB-Tech)'. Based on our results, further studies on APB-Tech should be focused on the possible improvement of ICSI outcomes and, thus, success rates.

Rationale and study design of a double-blinded prospective randomized clinical trial comparing euploidy rates among embryos created from sibling oocytes injected with sperm processed by microfluidics or by density gradient centrifugation

BACKGROUND

During the in vitro fertilization (IVF) process, sperm must be processed prior to insemination. While the most common method, density gradient centrifugation, can potentially damage sperm during centrifugation, a recent advancement in sperm processing uses a microfluidics system which selects for the most highly motile sperm. In selecting for these sperm which may be of higher quality, the euploidy rates of embryos created as a result may also be improved. The primary aim of this study is to compare the euploidy rates per mature oocyte between embryos created from sibling oocytes injected with sperm processed by microfluidics sorting or by density gradient centrifugation.

METHODS

This is a double-blinded prospective randomized sibling oocyte study including patients undergoing treatment with IVF with intracytoplasmic sperm injection (ICSI) and preimplantation genetic testing (PGT). After controlled ovarian hyperstimulation, oocytes from each patient will be separated into two groups. Each group will be randomized to sperm processed using either microfluidics or density gradient centrifugation and embryos biopsied for PGT to assess euploidy rates. A sample size of 686 oocytes in each group for a total of 1372 oocytes will provide 80% power to detect a significant difference in the euploidy rates per mature oocyte between the two groups. An ancillary study examining the relationship between sperm processing method and sperm DNA fragmentation will be assessed.

CONCLUSION

This study will offer insight into the sperm's contribution to embryo euploidy, and has the potential to provide an alternative method of improving euploidy rates in clinical practice.

The relevance of sperm morphology in male infertility

This brief report concerns the role of human sperm morphology assessment in different fields of male infertility: basic research, genetics, assisted reproduction technologies, oxidative stress. One of the best methods in studying sperm morphology is transmission electron microscopy (TEM) that enables defining the concept of sperm pathology and classifying alterations in non-systematic and systematic. Non-systematic sperm defects affect head and tail in variable ratio, whereas the rare systematic defects are characterized by a particular anomaly that marks most sperm of an ejaculate. TEM analysis and fluorescence in situ hybridization represent outstanding methods in the study of sperm morphology and cytogenetic in patients with altered karyotype characterizing their semen quality before intracytoplasmic sperm injection. In recent years, the genetic investigations on systematic sperm defects, made extraordinary progress identifying candidate genes whose mutations induce morphological sperm anomalies. The question if sperm morphology has an impact on assisted fertilization outcome is debated. Nowadays, oxidative stress represents one of the most important causes of altered sperm morphology and function and can be analyzed from two points of view: 1) spermatozoa with cytoplasmic residue produce reactive oxygen species, 2) the pathologies with inflammatory/oxidative stress background cause morphological alterations. Finally, sperm morphology is also considered an important endpoint in in vitro experiments where toxic substances, drugs, antioxidants are tested. We think that the field of sperm morphology is far from being exhausted and needs other research. This parameter can be still considered a valuable indicator of sperm dysfunction both in basic and clinical research.

A Review of the Impact of Microfluidics Technology on Sperm Selection Technique

Sperm sorting procedures depend on centrifugation processes. These processes produce oxidative stress and cell damage that are undesirable for in-vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI) outcomes because they affect fertilization and implantation chances. The microfluidic sperm selection technique has shown promise in this area. It can create a platform for isolating and manipulating good-quality sperm cells using diverse triggers such as mechanical factors, chemical agents, and temperature gradients. Furthermore, microfluidic platforms can direct sperm cells for IVF or sperm sorting by utilizing an approach that is passive or active. In this review, we explain the use of microfluidics technologies for sorting and arranging sperm cells for different purposes. We also discuss the use of microfluidics technology in selecting and assessing sperm parameters and how it affects male infertility.

Future of Male Infertility Evaluation and Treatment: Brief Review of Emerging Technology

Over the past few decades, there have been significant advances in male infertility, particularly in the development of novel diagnostic tools. Unfortunately, there remains a substantial number of patients that remain infertile despite these improvements. In this review, we take heed of the emerging technologies that will shape the future of male infertility diagnosis, evaluation and treatment. Improvement in computer-assisted semen analyses and portability allow males to obtain basic semen parameters from the comfort of their home. Additionally, breakthrough ultrasound technology allows for preoperative prediction of potential areas of spermatogenesis within the testes, high-resolution optics permits better visualization during microdissection testicular sperm extraction (mTESE), and artificial intelligence improves sperm selection and identification.

Comparison of sperm preparation methods to improve the recovery of mature spermatozoa in sub-fertile males

The integrity of chromatin in the spermatozoon is essential for reproductive outcome. The aim of this study was to evaluate the most effective and cost-effective method to reduce the percentage of spermatozoa with defects in chromatin decondensation for use in assisted reproductive technologies (ART) procedures. Sperm samples from 15 sub-fertile males were examined at CFA Naples to determine the sperm decondensation index (SDI), using the aniline blue test, before and after preparation, comparing density gradients with two different swim-up approaches. All three techniques led to a reduction in decondensed spermatozoa with no statistical difference (P > 0.05) between the control and the treated sperm. In contrast, we found a highly significant decrease in SDI (P < 0.01) after the two swim-up methods in all the samples, confirming the efficacy of these methods in lowering the percentage of chromatin compaction damage. There was no statistical difference between the two swim-up methods, however swim-up from the pellet led to improved count, motility and the percentage of normal condensed spermatozoa. We suggest that swim-up from the pellet be used in ART on sub-fertile males, both to reduce cell stress by multiple centrifugation and improve the recovery rate of mature spermatozoa.

The Effect of Sperm DNA Fragmentation on Male Fertility and Strategies for Improvement: A Narrative Review

The inability to conceive due to male infertility is a complex issue with a wide variety of etiologies. Sperm DNA damage can be both a barrier to natural pregnancy and successful assisted reproductive technology (ART). The aim of this narrative review was to describe and highlight the effects of sperm DNA fragmentation and the most recent data on various treatment strategies to decrease sperm DNA damage. Finally, we proposed a management algorithm for couples undergoing ART with increased sperm DNA fragmentation.

Embryologic outcomes among patients using a microfluidics chip compared to density gradient centrifugation to process sperm: a paired analysis

PURPOSE

To evaluate embryologic outcomes among paired IVF cycles in which a microfluidics chip was utilized compared to density gradient centrifugation for sperm processing.

METHODS

This was a retrospective cohort study of 88 paired IVF cycles from patients aged 18-44 years at a university-affiliated IVF center. Fresh cycles from patients undergoing ICSI with sperm processed by a microfluidics chamber (microfluidics cycles) were compared to the same patients' previous ICSI cycles in which sperm was processed via density gradient centrifugation (control cycles). The primary outcome was the high-quality blastulation rate.

RESULTS

High-quality blastulation rate per oocyte retrieved was significantly higher in the microfluidics group compared to the control group (21.1% versus 14.5%, p < 0.01) as was the blastulation rate per 2PN (42.7% versus 30.8%, p < 0.01). Fertilization rates were significantly higher in the microfluidics group. The euploidy rate per oocyte retrieved was significantly higher in the microfluidics group compared with the control group (8.5% versus 4.3%, p = 0.04), while the euploidy rate per embryo biopsied was comparable (32.6% versus 21.8%, p = 0.09). In patients with male factor infertility, the high-quality blastulation rate was similar between the control and microfluidics cycles. There was a significantly higher blastulation rate among microfluidics cycles in patients without a diagnosis of male factor infertility (p < 0.01).

CONCLUSION

In this study, several embryologic outcomes, including fertilization rate, high-quality blastulation rate, and euploidy rate, were significantly higher in the microfluidics group compared to the control group. Microfluidics sperm processing may be a way to improve embryologic outcomes.

Electrically-driven handling of gametes and embryos: taking a step towards the future of ARTs

Electrical stimulation of gametes and embryos and on-chip manipulation of microdroplets of culture medium serve as promising tools for assisted reproductive technologies (ARTs). Thus far, dielectrophoresis (DEP), electrorotation (ER) and electrowetting on dielectric (EWOD) proved compatible with most laboratory procedures offered by ARTs. Positioning, entrapment and selection of reproductive cells can be achieved with DEP and ER, while EWOD provides the dynamic microenvironment of a developing embryo to better mimic the functions of the oviduct. Furthermore, these techniques are applicable for the assessment of the developmental competence of a mammalian embryo in vitro. Such research paves the way towards the amelioration and full automation of the assisted reproduction methods. This article aims to provide a summary on the recent developments regarding electrically stimulated lab-on-chip devices and their application for the manipulation of gametes and embryos in vitro.

Selection of healthy sperm based on positive rheotaxis using a microfluidic device

For conception, sperm cells travel towards the oocyte. This journey is accomplished by only a few sperm cells, following various guidance mechanisms. Of these mechanisms, rheotaxis plays a significant role in guiding the sperm over a long distance. By taking advantage of this natural rheotaxis behavior of sperm, we have developed a microfluidic chip that isolates healthy sperm cells. The developed chip consists of different chambers separated by microchannels that facilitate separation of motile sperm cells from unprocessed semen samples with the help of fluid flow. The sperm cells are subjected to different velocities in different parts of the chip that direct functional sperm towards the collection chamber utilizing positive rheotaxis. The results from the developed microfluidic chip (with 0.5 μL min^-1 flow rate) have shown almost 100% motility, a significantly higher percentage of morphologically normal sperm cells with lesser sperm DNA fragmentation than the control (no-flow) and raw semen sample. This chip satisfies the need of a clinical setting as it is low-cost, easy to operate and uses a small semen volume for sperm sorting.

Selecting motile, non-apoptotic and induced spermatozoa for capacitation without centrifuging by MACS-Up method

In newly improved MACS-Up method, magnetic field has been applied to separate non-apoptotic spermatozoa directly from the neat semen. The spermatozoa during passing through a viscous layer, located on the neat semen, contacted with progesterone and induced for the capacitation. Then, a clean population of non-apoptotic, and capacitated spermatozoa were selected in the pure culture media. Selected spermatozoa may be useful for use in ART. The 80 semen samples from normozoospermic individuals were divided separately into 4 attempts. Semen analysis, SCSA (sperm chromatin structure assay), FLICA (fluorescein-labelled inhibitors of caspase) methods, immunoassay of phosphorylation of tyrosine residues of sperm proteins, nuclear DNA integrity, caspase 3 activity and sperm capacitation rate were all performed for evaluation of sperm parameters respectively. To examine all aspects, the MACS-Up method compared with DGC (density gradient centrifuging) and MACS-DGC methods separately. This method can isolate non-apoptotic spermatozoa directly from the neat semen, which has similar performance compared to the MACS-DGC method. Movement and passing spermatozoa through the viscous layer, and contact with progesterone, significantly induced spermatozoa for capacitation compared with the control group. Also, the MACS-Up in comparison with routine DGC method could select spermatozoa with significantly higher total and progressive motility, DNA integrity, induced sperm population for capacitation and normal morphology. MACS-Up can be developed as an effective, short-time, and ease of performing method and used practically to select functional spermatozoa as novel sperm selection procedure. However, for clinical use of MACS-Up, all clinical aspects of this method should be considered and evaluated.

SERPINA5 Protein in Cumulus-Oocyte Complexes Increases the Fertilisation Ability of Mouse Sperm

Obtaining high-quality sperm is key to improving the success rate of assisted reproductive technology (ART). Although cytokines secreted by cumulus-oocyte complexes (COCs) bind to sperm surface receptors to improve sperm quality, the effects of adding mouse COCs to human tubal fluid (HTF) medium on sperm capacitation have not yet been explored. Eight-week-old ICR mouse COCs were added to HTF medium and crushed to obtain the post-modified HTF medium. Compared with using HTF medium, the fertilisation rate and number of sperm combined with the zona pellucida significantly increased after in vitro capacitation using the post-modified HTF medium (P < 0.01). Proteomic and Western blotting analyses showed that the level of SERPINA5 in sperm increased significantly following in vitro capacitation with the post-modified HTF medium (P < 0.05). Immunohistochemical staining analysis demonstrated that SERPINA5 protein was expressed in mouse cumulus cells. A SERPINA5 antibody was added in the post-modified HTF medium to block the effects of SERPINA5 after in vitro capacitation, which significantly decreased the fertilisation rate and the number of sperm combined with the zona pellucida (P < 0.05). Recombinant mouse SERPINA5 protein (1 ~ 2 μg/ml) was added to HTF medium and the fertilisation rate and the number of sperm combined with the zona pellucida significantly increased (P < 0.01). Moreover, recombinant human SERPINA5 protein (5 μg/ml) was added before human semen freezing. Compared with adding no SERPINA5 protein, the percentage of normal sperm morphology and the intact acrosome significantly increased (P < 0.05). Our study provides a reference method for optimising sperm quality in the process of in vitro capacitation.

OUP accepted manuscript

BACKGROUND

Oocyte activation deficiency (OAD) is attributed to the majority of cases underlying failure of ICSI cycles, the standard treatment for male factor infertility. Oocyte activation encompasses a series of concerted events, triggered by sperm-specific phospholipase C zeta (PLCζ), which elicits increases in free cytoplasmic calcium (Ca²⁺) in spatially and temporally specific oscillations. Defects in this specific pattern of Ca²⁺ release are directly attributable to most cases of OAD. Ca²⁺ release can be clinically mediated via assisted oocyte activation (AOA), a combination of mechanical, electrical and/or chemical stimuli which artificially promote an increase in the levels of intra-cytoplasmic Ca²⁺. However, concerns regarding safety and efficacy underlie potential risks that must be addressed before such methods can be safely widely used.

OBJECTIVE AND RATIONALE

Recent advances in current AOA techniques warrant a review of the safety and efficacy of these practices, to determine the extent to which AOA may be implemented in the clinic. Importantly, the primary challenges to obtaining data on the safety and efficacy of AOA must be determined. Such questions require urgent attention before widespread clinical utilization of such protocols can be advocated.

SEARCH METHODS

A literature review was performed using databases including PubMed, Web of Science, Medline, etc. using AOA, OAD, calcium ionophores, ICSI, PLCζ, oocyte activation, failed fertilization and fertilization failure as keywords. Relevant articles published until June 2019 were analysed and included in the review, with an emphasis on studies assessing large-scale efficacy and safety.

OUTCOMES

Contradictory studies on the safety and efficacy of AOA do not yet allow for the establishment of AOA as standard practice in the clinic. Heterogeneity in study methodology, inconsistent sample inclusion criteria, non-standardized outcome assessments, restricted sample size and animal model limitations render AOA strictly experimental. The main scientific concern impeding AOA utilization in the clinic is the non-physiological method of Ca²⁺ release mediated by most AOA agents, coupled with a lack of holistic understanding regarding the physiological mechanism(s) underlying Ca²⁺ release at oocyte activation.

LIMITATIONS, REASONS FOR CAUTION

The number of studies with clinical relevance using AOA remains significantly low. A much wider range of studies examining outcomes using multiple AOA agents are required.

WIDER IMPLICATIONS

In addition to addressing the five main challenges of studies assessing AOA safety and efficacy, more standardized, large-scale, multi-centre studies of AOA, as well as long-term follow-up studies of children born from AOA, would provide evidence for establishing AOA as a treatment for infertility. The delivery of an activating agent that can more accurately recapitulate physiological fertilization, such as recombinant PLCζ, is a promising prospect for the future of AOA. Further to PLCζ, many other avenues of physiological oocyte activation also require urgent investigation to assess other potential physiological avenues of AOA.

STUDY FUNDING/COMPETING INTERESTS

D.G. was supported by Stanford University’s Bing Overseas Study Program. J.K. was supported by a Healthcare Research Fellowship Award (HF-14-16) made by Health and Care Research Wales (HCRW), alongside a National Science, Technology, and Innovation plan (NSTIP) project grant (15-MED4186-20) awarded by the King Abdulaziz City for Science and Technology (KACST). The authors have no competing interests to declare.

Is oxidative stress evaluated in viable human spermatozoa a marker of good semen quality?

BACKGROUND

Oxidative stress is defined as the unbalance between reactive oxygen species (ROS) production and antioxidant defences. Whereas low levels of ROS are necessary for physiological sperm functions, high levels impair fertility damaging membranes, proteins and DNA. In this study, we used two probes, CellROX^® Orange and Dihydroethidium (DHE), which reveal different intracellular ROS species, to evaluate the association between the percentage of oxidized viable spermatozoa and sperm functions.

METHODS

The percentage of oxidized spermatozoa was evaluated by flow cytometry with the two probes concomitantly with standard semen parameters and sperm DNA fragmentation (sDF, by TUNEL/PI). Phosphatidylserine membrane exposure, caspase 3,7 activity, sperm kinematic parameters and hyperactivated motility were evaluated by Annexin V, FLICA™ and CASA system respectively.

RESULTS

Oxidized viable spermatozoa, evaluated with both probes, were positively associated with sperm basal parameters and negatively with sDF. Also, we found that a consistent percentage of CellROX^® positive viable spermatozoa were selected from whole semen during swim up procedure. Double staining of CellROX^® Orange with Annexin V and FLICA™ demonstrated that viable oxidized spermatozoa do not show apoptotic features.

CONCLUSION

Overall, our results suggest that CellROX^® Orange and DHE allows identification of the viable oxidized sperm fraction related to better performances.

Sperm Selection for ICSI: Do We Have a Winner?

In assisted reproductive technology (ART), the aim of sperm cells’ preparation is to select competent spermatozoa with the highest fertilization potential and in this context, the intracytoplasmic sperm injection (ICSI) represents the most applied technique for fertilization. This makes the process of identifying the perfect spermatozoa extremely important. A number of methods have now been developed to mimic some of the natural selection processes that exist in the female reproductive tract. Although many studies have been conducted to identify the election technique, many doubts and disagreements still remain. In this review, we will discuss all the sperm cell selection techniques currently available for ICSI, starting from the most basic methodologies and continuing with those techniques suitable for sperm cells with reduced motility. Furthermore, different techniques that exploit some sperm membrane characteristics and the most advanced strategy for sperm selection based on microfluidics, will be examined. Finally, a new sperm selection method based on a micro swim-up directly on the ICSI dish will be analyzed. Eventually, advantages and disadvantages of each technique will be debated, trying to draw reasonable conclusions on their efficacy in order to establish the gold standard method.

ISAR Consensus Guidelines on Add-Ons Treatment in In vitro Fertilization

STUDY QUESTION

What are the good practices for the use of ADD-ON Treatments in IVF cycles in INDIA?

WHAT IS ALREADY KNOWN

Add on treatments in IVF are procedures and technologies which are offered to patients in hope of improving the success rates. A lot of add on treatments exist; most of them have limited evidence and data for the Indian patient population is miniscule. These interventions may have limited effects, so it is imperative that any new technology that is offered is evaluated properly and has enough evidence to suggest that it is safe and effective.

STUDY DESIGN SIZE DURATION

This is the report of a 2-day consensus meeting where two moderators were assigned to a group of experts to collate information on Add on treatments in IVF in INDIA. This meeting utilised surveys, available scientific evidence and personal laboratory experience into various presentations by experts on pre-decided specific topics.

PARTICIPANTS/MATERIALS SETTING METHODS

Expert professionals from ISAR representing clinical and embryology fields.

MAIN RESULTS AND THE ROLE OF CHANCE

The report is divided in various components including the health of the Offspring, the various ADD ons available to an ART center, consensus points for each technology & qualifications and trainings for embryologists, the report and recommendations of the expert panel reflect the discussion on each of the topics and try to lay down good practice points for labs to follow.

LIMITATIONS REASONS FOR CAUTION

The recommendations are solely based on expert opinion. Future availability of data may warrant an update of the same.

WIDER IMPLICATIONS OF THE FINDINGS

These guidelines can help labs across the country to standardise their ART services and improve clinical outcomes, it will also motivate clinics to collect data and report the use of Add ons to the national registry.

STUDY FUNDING/COMPETING INTERESTS

The consensus meeting and writing of the paper was supported by funds from CooperSurgical India.

Advancements in Microfluidic Systems for the Study of Female Reproductive Biology

The female reproductive tract is a highly complex physiological system that consists of the ovaries, fallopian tubes, uterus, cervix, and vagina. An enhanced understanding of the molecular, cellular, and genetic mechanisms of the tract will allow for the development of more effective assisted reproductive technologies, therapeutics, and screening strategies for female specific disorders. Traditional 2-dimensional and 3-dimensional static culture systems may not always reflect the cellular and physical contexts or physicochemical microenvironment necessary to understand the dynamic exchange that is crucial for the functioning of the reproductive system. Microfluidic systems present a unique opportunity to study the female reproductive tract, as these systems recapitulate the multicellular architecture, contacts between different tissues, and microenvironmental cues that largely influence cell structure, function, behavior, and growth. This review discusses examples, challenges, and benefits of using microfluidic systems to model ovaries, fallopian tubes, endometrium, and placenta. Additionally, this review also briefly discusses the use of these systems in studying the effects of endocrine disrupting chemicals and diseases such as ovarian cancer, preeclampsia, and polycystic ovarian syndrome.

Technological Advancements in Male Infertility Microsurgery

There have been significant advancements in male infertility microsurgery over time, and there continues to be significant promise for new and emerging techniques, technologies, and methodologies. In this review, we discuss the history of male infertility and the evolution of microsurgery, the essential role of education and training in male infertility microsurgery, and new technologies in this space. We also review the potentially important role of artificial intelligence (AI) in male infertility and microsurgery.

Single cell analysis of DNA in more than 10,000 individual sperm from men with abnormal reproductive outcomes

PURPOSE

This pilot study sought to (1) validate the use of a novel technology for single-sperm-cell genome sequencing (Sperm-seq) in infertile men who may not have optimal quantity or quality of sperm for genomic analysis and (2) compare these results to fertile donors.

METHODS

Infertile men undergoing IVF with female partners with a previous history of failed fertilization with ICSI (FF) or poor blastulation of embryos (PB) were recruited from a large IVF center. Sperm-seq was used to analyze thousands of individual sperm and was carried out at an affiliated university research institute. Global aneuploidy rate, crossover locations, and crossover frequencies were assessed in the infertile population, and compared with a control group of 20 fertile donors, which were analyzed previously at the same laboratory.

RESULTS

Eight patients were initially included, but 3 samples did not yield high-quality genomic data for analysis. A total of 10,042 sperm were analyzed from 5 patients, 2 in the FF group, and 3 in the PB group. The global aneuploidy rate among the samples was 2-4%, similar to the control group. Likewise, crossover locations and frequencies were similar.

CONCLUSION

Sperm-seq provides a robust analysis but may not be applicable to all male infertility cases due to technical limitations. This group of male infertility patients did not have higher rates of aneuploidy or abnormal crossover patterns compared to a fertile donor population. Our data may suggest that FF and PB phenotypes may not be related to sperm aneuploidy or meiotic errors but rather to other intrinsic nuclear anomalies.

In vitro fertilization and andrology laboratory in 2030: expert visions

The aim of this article is to gather 9 thought leaders and their team members to present their ideas about the future of in vitro fertilization and the andrology laboratory. Although we have seen much progress and innovation in the laboratory over the years, there is still much to come, and this article looks at what these leaders think will be important in the future development of technology and processes in the laboratory.

CRISP2, CATSPER1 and PATE1 Expression in Human Asthenozoospermic Semen

The etiology of human asthenozoospermia is multifactorial. The need to unveil molecular mechanisms underlying this state of infertility is, thus, impelling. Circular RNAs (circRNAs) are involved in microRNA (miRNA) inhibition by a sponge activity to protect mRNA targets. All together they form the competitive endogenous RNA network (ceRNET). Recently, we have identified differentially expressed circRNAs (DE-circRNAs) in normozoospermic and asthenozoospermic patients, associated with high-quality (A-spermatozoa) and low-quality (B-spermatozoa) sperm. Here, we carried out a differential analysis of CRISP2, CATSPER1 and PATE1 mRNA expression in good quality (A-spermatozoa) and low quality (B-spermatozoa) sperm fractions collected from both normozoospermic volunteers and asthenozoospermic patients. These sperm fractions are usually separated on the basis of morphology and motility parameters by a density gradient centrifugation. B-spermatozoa showed low levels of mRNAs. Thus, we identified the possible ceRNET responsible for regulating their expression by focusing on circTRIM2, circEPS15 and circRERE. With the idea that motility perturbations could be rooted in quantitative changes of transcripts in sperm, we evaluated circRNA and mRNA modulation in A-spermatozoa and B-spermatozoa after an oral amino acid supplementation known to improve sperm motility. The profiles of CRISP2, CATSPER1 and PATE1 proteins in the same fractions of sperm well matched with the transcript levels. Our data may strengthen the role of circRNAs in asthenozoospermia and shed light on the molecular pathways linked to sperm motility regulation.

A microfluidic sperm-sorting device reduces the proportion of sperm with double-stranded DNA fragmentation

Sperm DNA fragmentation can be produced in one (ssSDF) or both (dsSDF) DNA strands, linked to difficulties in naturally achieving a pregnancy and recurrent miscarriages, respectively. The techniques more frequently used to select sperm require centrifugation, which may induce sperm DNA fragmentation (SDF). The objective of this study was to assess whether the microfluidic-based device FertileChip® (now ZyMot®ICSI) can diminish the proportion of sperm with dsSDF. First, in a blinded split pilot study, the semen of nine patients diagnosed with ≥60% dsSDF, was divided into three aliquots: not processed, processed with FertileChip®, and processed with swim up. The three aliquots were all analyzed using neutral COMET for the detection of dsSDF, resulting in a reduction of 46% (P < 0.001) with FertileChip® (dsSDF: 34.9%) compared with the ejaculate and the swim up (dsSDF: 65%). Thereafter, the FertileChip® was introduced into clinical practice and a cohort of 163 consecutive ICSI cycles of patients diagnosed with ≥60% dsSDF was analyzed. Fertilization rate was 75.41%. Pregnancy rates after the first embryo transfer were 53.2% (biochemical), 37.8% (clinical), 34% (ongoing) and the live birth rate was 28.8%. Cumulative pregnancy rates after one (65.4% of patients), two (27.6% of patients) or three (6.4% of patients) transfers were 66% (biochemical), 56.4% (clinical), 53.4% (ongoing) and the live birth rate was 42%. The selection of spermatozoa using Fertile Chip® significantly diminishes the percentage of dsSDF, compared with either the fresh ejaculate or after swim up. Its applicability in ICSI cycles of patients with high dsSDF resulted in good laboratory and clinical outcomes.

A Review on Microfluidics: An Aid to Assisted Reproductive Technology

Infertility is a state of the male or female reproductive system that is defined as the failure to achieve pregnancy even after 12 or more months of regular unprotected sexual intercourse. Assisted reproductive technology (ART) plays a crucial role in addressing infertility. Various ART are now available for infertile couples. Fertilization in vitro (IVF), intracytoplasmic sperm injection (ICSI) and intrauterine insemination (IUI) are the most common techniques in this regard. Various microfluidic technologies can incorporate various ART procedures such as embryo and gamete (sperm and oocyte) analysis, sorting, manipulation, culture and monitoring. Hence, this review intends to summarize the current knowledge about the application of this approach towards cell biology to enhance ART.

Recent Microfluidic Innovations for Sperm Sorting

Sperm selection is a clinical need for guided fertilization in men with low-quality semen. In this regard, microfluidics can provide an enabling platform for the precise manipulation and separation of high-quality sperm cells through applying various stimuli, including chemical agents, mechanical forces, and thermal gradients. In addition, microfluidic platforms can help to guide sperms and oocytes for controlled in vitro fertilization or sperm sorting using both passive and active methods. Herein, we present a detailed review of the use of various microfluidic methods for sorting and categorizing sperms for different applications. The advantages and disadvantages of each method are further discussed and future perspectives in the field are given.

Use of zona pellucida-bound spermatozoa as a natural selection in improvement of ICSI outcomes: A systematic review and meta-analysis

Zona pellucida (ZP)-bound spermatozoa have normal morphology and motility and can enhance the ICSI outcomes. Selection of zona pellucida-bound spermatozoa is recently considered to find functional spermatozoa for ICSI. This study reviewed the efficacy of ZP-bound sperm selection on the ICSI outcomes includes fertilisation rate, embryo quality, embryo transfer rate and clinical pregnancy rate. The databases searched include PubMed, Scopus and Cochrane databases up to January 2019. All research reports with full text and in English language that addressing the relation between ZP-sperm selection and ICSI outcomes were included. Fifty studies were suitable after screening of the 845 identified articles. After exclusions, five of these studies were included. Meta-analytic pooling of data indicated no association between the ICSI outcomes and ZP-bound sperm selection except a marginal effect on implantation rate. Eliminating one study indicated that ZP-bound sperm selection technique improves embryo quality, implantation rate and clinical pregnancy rate. This study revealed that ZP-bound sperm selection produces only a slight improvement in implantation rate. However, further studies with a large number of couples must be done to clarify the potential beneficial effect of ZP-bound spermatozoa on ICSI outcomes.

A new open-source hardware device to measure vertical sperm motility and concentration

Sperm motility and concentration are commonly evaluated parameters in semen analysis. Those parameters are assessed objectively with commercial instrumentation such as computer-assisted sperm analysis systems (CASA) and hemocytometer. In CASA systems, sperm motility is assessed in the horizontal plane imposed by the stage of the microscope. Thus, there is lack of measurement of the vertical velocity of sperm. The female reproductive tract is a tridimensional space which the sperm traverse to reach the ovum, and there is a need for instruments measuring parameters more relevant to this real-world situation. In this report we describe the design, construction and use of an open-source hardware (OSH) device for evaluation of the vertical velocity of sperm, called UPSPERM. This device was also used to measure sperm concentration, and agreement with hemocytometer was evaluated. Bland-Altman analysis shows good agreement between these two methods of sperm counting. As a first application of UPSPERM, we evaluated the changes in boar sperm motility at distinct pH values between 7.0 and 8.0. The UPSPERM results showed that the vertical velocity of sperm was highest at pH 7.6 and 7.8. We propose that our UPSPERM offers a reliable and affordable option for obtaining measurements of vertical velocity and sperm concentration.

Sperm selection during ICSI treatments reduces single- but not double-strand DNA break values compared to the semen sample

PURPOSE

To detect a possible bias in sperm DNA fragmentation (SDF) testing when performed on semen samples or on those few spermatozoa selected for Intracytoplasmic Sperm Injection (ICSI) treatments.

METHODS

A multimethodological analysis of Single- and Double-Strand DNA Breaks (SSB and DSB, respectively) was performed through the Neutral Comet, the Alkaline Comet, the Sperm Chromatin Dispersion (SCD) and the Terminal deoxynucleotidyl transferase dUTP Nick End Labelling (TUNEL) assays. SDF was evaluated in (i) semen samples from 23 infertile patients (not achieving pregnancy or suffering recurrent miscarriage); (ii) samples after a Swim-up and (iii) spermatozoa microselected for ICSI (ICSI-S).

RESULTS

The analysis of 3217 ICSI-S revealed a significant reduction of SSB values compared to the Ejaculate and the Swim-up samples. On the contrary, DSB values were not reduced after any sperm selection method. The No-pregnancy group presented poorer semen parameters and higher SSB values. The Recurrent miscarriage group presented better semen parameters but also higher DSB values.

CONCLUSION

The analysis of SDF on semen samples may not be fully representative of those few spermatozoa selected for ICSI. Since oxidative stress impairs sperm motility and causes SSB, selecting a motile sperm may intrinsically imply choosing a sperm not affected by this damage. DSB have an enzymatic origin which does not affect motility, making it difficult to select a sperm without this damage. Therefore, ICSI treatments could be effective in patients presenting high SSB values. Patients presenting high DSB values should expect bad ICSI results if this damage is not reduced through other specific methods.

In Vitro Maturation of Cumulus-Oocyte Complexes and In Vitro Sperm Capacitation Significantly Increase the Expression and Enhance the Location of the CXCL12 and CXCR4 Anchoring Attractant Complex in Pigs

Simple Summary

The process of mammalian fertilization is dependent on many mechanisms mediated by regulatory genes and proteins expressed in the gametes and/or the female genital tract. This study aimed to determine the expression and location of the cytokine complex CXCL12:CXCR4 in the porcine gametes: oocytes and spermatozoa. This complex is known to play a pivotal role for sperm attraction towards the oocyte prior to internal fertilization in several mammalian species. Gene and protein expressions were analyzed in female and male porcine gametes. The results showed that the CXCL12 gene expression was higher in mature cumulus cells, and CXCR4 was higher in capacitated spermatozoa, both being requisites for gametes to accomplish fertilization. Moreover, for the first time, the CXCL12 protein was located in the cytoplasm of cumulus cells from mature COCs, and the CXCR4 protein was expressed in the midpiece and principal piece of uncapacitated spermatozoa and also in the sperm head of capacitated spermatozoa. These findings increase our current knowledge on porcine physiology of fertilization and reproduction, leading to possible improvements in the performance of reproductive technologies.

Abstract

Successful internal fertilization in mammals depends on several mechanisms, including those triggering the so-called “sperm attraction” towards the oocyte, which include some oocyte-derived sperm chemoattractants and interactive protein complexes, such as the cytokine C-X-C motif chemokine 12/C-X-C chemokine receptor type 4 (CXCL12-CXCR4) receptor complex. The presence and precise localization of these crucial proteins was determined hereby, for the first time, in porcine cumulus–oocyte complexes (COCs) and spermatozoa. CXCL12 was overexpressed in the cumulus cells of in vitro matured, compared to immature COCs (p < 0.05), with its receptor (CXCR4) being up-regulated in capacitated spermatozoa (p < 0.03) compared to uncapacitated spermatozoa. The CXCR4 appeared specifically localized in the sperm tail of non-capacitated spermatozoa and also in the sperm head of capacitated spermatozoa, suggesting that the CXCL12-CXCR4 signaling complex would play a pivotal role in attracting capacitated spermatozoa towards the oocyte, facilitating fertilization in pigs.