Efficiency of hyaluronic acid (HA) sperm selection

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.

Influence of a hyaluronan-binding system for sperm selection in intracytoplasmic sperm injection cycles on embryo morphokinetic parameters and in vitro fertilization cycle outcomes

PURPOSE

Although the impact of the paternal contribution to embryo quality and blastocyst formation is a well-known phenomenon, the current literature provides insufficient evidence that hyaluronan-binding sperm selection methods improve assisted reproductive treatment outcomes. Thus, we compared the cycle outcomes of morphologically selected intracytoplasmic sperm injection (ICSI) with hyaluronan binding physiological intracytoplasmic sperm injection (PICSI) cycles.

METHODS

A total of 2415 ICSI and 400 PICSI procedures of 1630 patients who underwent in vitro fertilization cycles using a time-lapse monitoring system between 2014 and 2018 were analyzed retrospectively. Fertilization rate, embryo quality, clinical pregnancy rate, biochemical pregnancy rate and miscarriage rate were evaluated, differences in morphokinetic parameters and cycle outcomes were compared.

RESULTS

In total, 85.8 and 14.2% of the whole cohort were fertilized with standard ICSI and PICSI, respectively. The proportion of fertilized oocytes did not significantly differ between groups (74.53 ± 1.33 vs. 72.92 ± 2.64, p > 0.05). Similarly, the proportion of good-quality embryos according to the time-lapse parameters and the clinical pregnancy rate did not significantly differ between groups (71.93 ± 4.21 vs. 71.33 ± 2.64, p > 0.05 and 45.55 ± 2.91 vs. 44.96 ± 1.25, p > 0.05). No statistically significant differences were found between groups in clinical pregnancy rates (45.55 ± 2.91 vs. 44.96 ± 1.25, p > 0.05). Biochemical pregnancy rates (11.24 ± 2.12 vs. 10.85 ± 1.83, p > 0.05) and miscarriage rates (24.89 ± 3.74 vs. 27.91 ± 4.91, p > 0.05) were not significantly different between groups.

CONCLUSION

The effects of the PICSI procedure on fertilization rate, biochemical pregnancy rate, miscarriage rate, embryo quality, and clinical pregnancy outcomes were not superior. The effect of the PICSI procedure on embryo morphokinetics was not apparent when all parameters were considered.

Sperm Adhesion Molecule 1 (SPAM1) Distribution in Selected Human Sperm by Hyaluronic Acid Test

The failures of binding to the oocyte zona pellucida are commonly attributed to defects in the sperm recognition, adhesion, and fusion molecules. SPAM1 (sperm adhesion molecule 1) is a hyaluronidase implicated in the dispersion of the cumulus-oocyte matrix. Therefore, the aim of this study was to characterize the SPAM1 distribution in the different physiological conditions of human sperm. Specifically, we evaluated the location of the SPAM1 protein in human sperm before capacitation, at one and four hours of capacitation and after hyaluronic acid (HA) selection test by fluorescence microscopy. Sperm bound to HA were considered mature and those that crossed it immature. Our results detected three SPAM1 fluorescent patterns: label throughout the head (P1), equatorial segment with acrosomal faith label (P2), and postacrosomal label (P3). The data obtained after recovering the mature sperm by the HA selection significantly (p < 0.05) highlighted the P1 in both capacitation times, being 79.74 and 81.48% after one hour and four hours, respectively. Thus, the HA test identified that human sperm require the presence of SPAM1 throughout the sperm head (P1) to properly contact the cumulus-oocyte matrix. Overall, our results provide novel insights into the physiological basis of sperm capacitation and could contribute to the improvement of selection techniques.

Sperm selection with hyaluronic acid improved live birth outcomes among older couples and was connected to sperm DNA quality, potentially affecting all treatment outcomes

STUDY QUESTION

What effects did treatment using hyaluronic acid (HA) binding/selection prior to ICSI have on clinical outcomes in the Hyaluronic Acid Binding sperm Selection (HABSelect) clinical trial?

SUMMARY ANSWER

Older women randomized to the trial's experimental arm (selection of sperm bound to immobilized (solid-state) HA) had the same live birth rates as younger women, most likely a result of better avoidance of sperm with damaged DNA.

WHAT IS KNOWN ALREADY

Recent randomized controlled trials (RCTs) investigating the efficacy of HA-based sperm selection prior to ICSI, including HABSelect, have consistently reported reductions in the numbers of miscarriages among couples randomized to the intervention, suggesting a pathological sperm-mediated factor mitigated by prior HA-binding/selection. The mechanism of that protection is unknown.

STUDY DESIGN, SIZE, DURATION

The original HABSelect Phase 3 RCT ran from 2014 to 2017 and included 2752 couples from whom sperm samples used in control (ICSI) and intervention (Physiological IntraCytoplasmic Sperm Injection; PICSI) arms of the trial were stored frozen for later assessment of DNA quality (DNAq). The trial overlapped with its mechanistic arm, running from 2016 to 2018.

PARTICIPANTS/MATERIALS, SETTING, METHODS

As miscarriage reduction was a significant secondary outcome of the trial, samples (n = 1247) selected for the mechanistic analysis were deliberately enriched for miscarriage outcomes (n = 92 or 7.4%) from a total of 154 miscarriages (5.6%) among all (n = 2752) couples randomized by stratified random sampling. Values from fresh semen samples for sperm concentration (mml), percentage forward progressive motility and percentage HA-binding score (HBS) were obtained before being processed by differential density gradient centrifugation or (rarely) by swim-up on the day of treatment. Surplus sperm pellets were recovered, aliquoted and cryopreserved for later analysis of DNAq using slide-based Comet, TUNEL, acridine orange (AO) and the sperm chromatin dispersion (SCD) assays. Following their classification into normal and abnormal sample subcategories based on reference values for sperm concentration and motility, relationships with HBS and DNAq were examined by Spearman correlation, Student's t-tests, Mann Whitney U tests, and logistic regression (univariable and multivariable). Parsimonious selection enabled the development of models for exploring and explaining data trends. Potential differences in future cumulative pregnancy rates relating to embryo quality were also explored.

MAIN RESULTS AND THE ROLE OF CHANCE

Results from the 1247 sperm samples assayed for HBS and/or DNAq, generated data that were considered in relation to standard physiological measures of (sperm) vitality and to treatment outcomes. All measures of HBS and DNAq discriminated normal from abnormal sperm samples (P < 0.001). SCD correlated negatively with the Comet (r = -0.165; P < 0.001) and TUNEL assays (r = -0.200; P < 0.001). HBS correlated negatively with AO (r = -0.211; P < 0.001), Comet (r = -0.127; P < 0.001) and TUNEL (r = -0.214; P < 0.001) and positively with SCD (r = 0.255; P < 0.001). A model for predicting live birth (and miscarriage) rates included treatment allocation (odds ratio: OR 2.167, 95% CI 1.084-4.464, P = 0.031), female age (OR 0.301, 95% CI 0.133-0.761, P = 0.013, per decade) and the AO assay (OR 0.79, 95% CI 0.60-1. 02.761, P = 0.073, per 10 points rise). A model predicting the expected rate of biochemical pregnancy included male age (OR 0.464, 95% CI 0.314-0.674, P < 0.001, per decade) and the SCD assay (OR 1.04, 95% CI 1.007-1.075, P = 0.018, per 10 point rise). A model for conversion from biochemical to clinical pregnancy did not retain any significant patient or assay variables. A model for post-injection fertilization rates included treatment allocation (OR 0.83, 95% CI 0.75-0.91, P < 0.001) and the Comet assay (OR 0.950, 95% CI 0.91-1.00, P = 0.041).

LIMITATIONS, REASONS FOR CAUTION

HABSelect was a prospective RCT and the mechanistic study group was drawn from its recruitment cohort for retrospective analysis, without the full benefit of randomization. The clinical and mechanistic aspects of the study were mutually exclusive in that measures of DNAq were obtained from residual samples and not from HA-selected versus unselected sperm. Models for fitting mechanistic with baseline and other clinical data were developed to compensate for variable DNAq data quality. HABSelect used a solid-state version of PICSI and we did not assess the efficacy of any liquid-state alternatives. PICSI reduced fertilization rates and did not improve the outlook for cumulative pregnancy rates.

WIDER IMPLICATIONS OF THE FINDINGS

Notwithstanding the interventional effect on fertilization rates and possibly blastocyst formation (neither of which influenced pregnancy rates), poor sperm DNAq, reflected by lower HBS, probably contributed to the depression of all gestational outcomes including live births, in the HABSelect trial. The interventional avoidance of defective sperm is the best explanation for the equalization in live birth rates among older couples randomized to the trial's PICSI arm. As patients going forward for assisted conception cycles globally in future are likely to be dominated by an older demographic, HA-based selection of sperm for ICSI could be considered as part of their treatment plan.

STUDY FUNDING/COMPETING INTEREST(S)

The study was supported by the National Institute for Health Research (NIHR) EME (Efficacy and Mechanism Evaluation)-11-14-34. National Research Ethics Service approval 11/06/2013: 13/YH/0162. S.L. is CEO of ExamenLab Ltd (company number NI605309).

TRIAL REGISTRATION NUMBER

ISRCTN99214271.

Prolonged exposure of human spermatozoa in polyvinylpyrrolidone has detrimental effects on sperm biological characteristics

Polyvinylpyrrolidone (PVP) has been utilized in intracytoplasmic sperm injection (ICSI) for immobilization and manipulation of spermatozoa. This study aims to determine the suitable time that sperm cells could be safely exposed to PVP during ICSI procedure. Twenty-five normal semen samples were prepared using the swim-up method and then were exposed to 10% PVP at different time intervals (15, 30 and 60 min). The effect of PVP on sperm parameters (viability and morphology), DNA fragmentation index (sperm chromatin dispersion test), chromatin quality (aniline blue, toluidine blue and chromomycin A3 staining), acrosome reaction, mitochondrial membrane potential and sperm ultrastructure was assessed at different time intervals. Our results showed that prolonged sperm exposure in PVP for 15, 30 and 60 min significantly affects viability and morphology with a concomitant increase in DNA fragmentation and abnormal chromatin structure, while the percentage of acrosome-reacted spermatozoa was additionally increased. In addition, the spermatozoa with high mitochondrial membrane potential were significantly decreased compared to unexposed spermatozoa to PVP. In conclusion, the detrimental effects of PVP were increased significantly following sperm exposure in PVP after 15 min. Therefore, the sperm exposure to PVP should be limited to less than 15 min during ICSI procedure.

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.

Sperm Selection Technology in ART

Intracytoplasmic sperm injection (ICSI) is a commonly used in vitro fertilization technique. Selection of sperm for injection is currently done using subjective assessment of morphology, which may not accurately identify the best-quality sperm. Hyaluronic acid receptors on sperm plasma membranes are a marker of maturity, and sperms which are capable of binding immobilized hyaluronic acid in vitro are of higher quality. This can be used as an advanced sperm selection technique to choose sperm for ICSI, termed physiological ICSI (PICSI). Several studies reported improved fertility treatment outcomes when using PICSI compared with conventional ICSI; however, the majority of studies are underpowered. Recently, a large, multicenter, randomized controlled trial, known as the Hyaluronic Acid Binding Sperm Selection (HABSelect) trial, found a significant reduction in miscarriage rates with PICSI, but no significant effect on live birth rate. There are still many avenues through which PICSI may provide an advantage, subject to confirmation by future research, such as improved long-term health of offspring. Other advanced sperm selection techniques include intracytoplasmic morphologically selected sperm injection, magnetic-activated cell sorting, and Zeta potential sperm selection; however, the most recent Cochrane review concluded that there is currently insufficient evidence to ascertain whether these techniques improve clinical outcomes, such as live birth rates.

Reproductive Outcomes of Different Sperm Selection Techniques for ICSI Patients with Abnormal Sperm DNA Fragmentation: a Randomized Controlled Trial

The aim of the study is to compare the reproductive outcomes of different sperm selection techniques: density gradient centrifugation (DGC), testicular sperm (Testi), physiological ICSI (PICSI), and magnetic-activated cell sorting (MACS) in abnormal sperm DNA fragmentation (SDF) ICSI patients. A randomized controlled trial included 302 patients with abnormal SDF undergoing ICSI where they were randomized into 4 groups: a control group of DGC (n= 72), Testi (n=73), PICSI (n=78), and MACS (n=79). Results showed no significant differences in the male age, female age, or SDF between the four groups. Testi group had significantly lower cleavage and blastulation rates compared to PICSI, DGC, or MACS groups (p =0.001). For the high-quality blastocysts, DGC and MACS groups had significantly higher rate than the Testi group (p =0.014). The highest pregnancy rate was scored for the PICSI group (69.6%), while the lowest pregnancy rate was scored for the DGC group (51.4%) with (p =0.025). The PICSI group showed a significantly higher implantation rate compared to the other groups (p =0.003). Regarding the ongoing pregnancy rate, the significant difference was observed between the PICSI (62.8%) and MACS (62%) vs. DGC (45.8%). Besides, no significant differences were found in the miscarriage rates between the four groups. In conclusion, PICSI and MACS along with DGC showed significant improvement in embryological and clinical outcome over testicular sperm or sperm processed by DGC alone in patients with abnormal SDFRegistration number: NCT04482517.

Sperm DNA Fragmentation: A New Guideline for Clinicians

Sperm DNA integrity is crucial for fertilization and development of healthy offspring. The spermatozoon undergoes extensive molecular remodeling of its nucleus during later phases of spermatogenesis, which imparts compaction and protects the genetic content. Testicular (defective maturation and abortive apoptosis) and post-testicular (oxidative stress) mechanisms are implicated in the etiology of sperm DNA fragmentation (SDF), which affects both natural and assisted reproduction. Several clinical and environmental factors are known to negatively impact sperm DNA integrity. An increasing number of reports emphasizes the direct relationship between sperm DNA damage and male infertility. Currently, several assays are available to assess sperm DNA damage, however, routine assessment of SDF in clinical practice is not recommended by professional organizations. This article provides an overview of SDF types, origin and comparative analysis of various SDF assays while primarily focusing on the clinical indications of SDF testing. Importantly, we report four clinical cases where SDF testing had played a significant role in improving fertility outcome. In light of these clinical case reports and recent scientific evidence, this review provides expert recommendations on SDF testing and examines the advantages and drawbacks of the clinical utility of SDF testing using Strength-Weaknesses-Opportunities-Threats (SWOT) analysis.

Sperm selection strategies and their impact on assisted reproductive technology outcomes

The application of assisted reproductive technologies (ART) has revolutionised the treatment of human infertility, giving hope to the patients previously considered incapable of establishing pregnancy. While semen analysis is performed to access whether a sample has an adequate number of viable, motile and morphologically normal sperm cells able to achieve fertilisation, sperm selection techniques for ART aim to isolate the most competent spermatozoon which is characterised by the highest fertilising potential. Based on the semen analysis results, the correct sperm selection technique must be chosen and applied. In this review, different sperm selection strategies for retrieving spermatozoa with the highest fertilising potential and their impact on ART outcomes are discussed. In addition, advantages and disadvantages of each method and the best suited techniques for each clinical scenario are described.

Novel Techniques of Sperm Selection for Improving IVF and ICSI Outcomes

Almost 50% of the infertility cases are due to male factors. Assisted reproductive technologies (ARTs) allow to overcome the incapacity of these patients' spermatozoa to fertilize the oocyte and produce a viable and healthy offspring, but the efficiency of the different techniques has still the potential to improve. According to the latest reports of the European Society of Human Reproduction and Embryology (ESHRE) and the Centers for Disease Control and Prevention of the United States (CDC), the percentages of deliveries per ART cycle in 2014 and 2016 were 21 and 22%, respectively. Among the reasons for this relatively low efficiency, the quality of the spermatozoa has been pointed out as critical, and the presence of high percentages of DNA-damaged spermatozoa in patients' ejaculates is possibly one of the main factors reducing the ARTs outcomes. Thus, one of the main challenges in reproductive medicine is to ensure the highest quality of the spermatozoa used in ARTs, and specifically, in terms of genetic integrity. The latest techniques for the preparation and selection of human spermatozoa are herein discussed focusing on those proven to improve one or several of the following parameters: sperm genetic integrity, fertilization capacity, embryo production, and in vitro survival, as well as pregnancy and delivery rates following in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). In addition, we discuss the potential of techniques developed in non-human mammals that could be further transferred to the clinic.

Zeta and hyaluronic acid assessments, novel sperm selection procedures, in animal model for male infertility

Considering varicocele (VCL)-induced severe, progressive DNA damage, histone-protamine anomalies and low sperm production, in the current study, the experimental VCL was induced and the efficiency of hyaluronic acid (HA)-binding method (HABM) and zeta preparation procedure (ZPP) in selection of appropriate spermatozoa was compared with those spermatozoa from intact animals. Following 2 and 4 months, the histological alterations in testicular tissue, sperm count and viability were assessed to prove the VCL condition. The spermatozoa were undergone simple wash, HABM and ZPP. The chromatin condensation, active caspase-3 expression, DNA fragmentation and apoptosis index were analysed after applying selection techniques and compared with the spermatozoa from intact and VCL-induced animals, which were undergone a simple wash. Observations showed that both HABM and ZPP effectively prepared the spermatozoa with higher chromatin condensation and lower DNA damage. Meanwhile, the ZPP exerted a more preferable effect by preparing the spermatozoa with higher chromatin condensation, and lower caspase-3 expression, and DNA disintegrity versus the HABM, especially after 4 months. In conclusion, ZPP seems to exert much more reliable efficiency in selecting appropriate spermatozoa for ICSI processes, while more studies are needed to find out which one is more useful in the clinical assisted reproductive technique (ART) process.

Live birth and miscarriage rate following intracytoplasmic morphologically selected sperm injection vs intracytoplasmic sperm injection: An updated systematic review and meta-analysis

INTRODUCTION

Intracytoplasmic morphologically selected sperm injection (IMSI) is one of the sperm selection techniques used for assisted reproduction which has been applied for a variety of indications including previously failed fertilization with intracytoplasmic sperm injection (ICSI). A Cochrane review¹ found no difference in outcomes between either modality of sperm selection. Since the Cochrane review was published there have been a further two randomized controlled trials comparing IMSI and ICSI. This systematic review and meta-analysis aims to compare IMSI with ICSI as insemination methods regarding live birth rate and miscarriage rate.

MATERIAL AND METHODS

Systematic review of randomized controlled trials, observational studies and similar reviews in electronic databases published before January 2018.

RESULTS

We found nine randomized controlled trials, evaluating 1610 cycles of in vitro fertilization and 15 observational studies evaluating 1243 cycles of in vitro fertilization. Meta-analysis of the included randomized controlled trials showed no difference in the live birth rate or miscarriage rate between the ICSI and IMSI groups. Meta-analysis of five observational studies showed a significantly higher number of live births in the IMSI group than ICSI group (live birth rate odds ratio 1.47, 95% confidence interval 1.16-4.07), with a moderate degree of heterogeneity (I²  = 41%). Additionally, from six observational studies, a significantly lower miscarriage rate was observed in the IMSI group than in the ICSI group (odds ratio 0.51, 95% confidence interval 0.37-0.70, I²  = 0%).

CONCLUSIONS

Meta-analysis of randomized studies comparing IMSI to ICSI has not shown any difference in live birth rate and miscarriage rate. Meta-analysis of observational studies, which must be interpreted with caution, revealed an increased live birth rate and decreased miscarriage rate with IMSI vs ICSI.

Advanced sperm selection techniques for assisted reproduction

BACKGROUND

Assisted reproductive technologies (ART) including in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI), combine gametes to enhance the probability of fertilisation and pregnancy. Advanced sperm selection techniques are increasingly employed in ART, most commonly in cycles utilising ICSI. Advanced sperm selection techniques are proposed to improve the chance that structurally intact and mature sperm with high DNA integrity are selected for fertilisation. Strategies include selection according to surface charge; sperm apoptosis; sperm birefringence; ability to bind to hyaluronic acid; and sperm morphology under ultra-high magnification. These techniques are intended to improve ART outcomes.

OBJECTIVES

To evaluate the effectiveness and safety of advanced sperm selection techniques on ART outcomes.

SEARCH METHODS

We conducted a systematic search of electronic databases (Cochrane Gynaecology and Fertility Group Specialised Register, CENTRAL via the Cochrane Register of Studies Online, MEDLINE, Embase, PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL); trials registers (ClinicalTrials.gov, Current Controlled Trials, and the World Health Organization International Clinical Trials Registry Platform); conference abstracts (Web of Knowledge); and grey literature (OpenGrey) for relevant randomised controlled trials (RCTs). We handsearched the reference lists of included studies and similar reviews. The search was conducted in June 2018.

SELECTION CRITERIA

We included RCTs comparing advanced sperm selection techniques versus standard IVF, ICSI, or another technique. We excluded studies of intracytoplasmic morphologically selected sperm injection (IMSI), as they are subject to a separate Cochrane Review. Primary outcomes measured were live birth and miscarriage per woman randomly assigned. Secondary outcome measures included clinical pregnancy per woman randomly assigned. Secondary adverse events measured included miscarriage per clinical pregnancy and foetal abnormality.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility and risk of bias and extracted data. Any disagreements were resolved by consultation with a third review author. We consulted study investigators to resolve queries. Risk ratios (RRs) were calculated with 95% confidence intervals (CIs). We combined studies using a fixed-effect model. We evaluated the quality of the evidence using GRADE methods.

MAIN RESULTS

We included eight RCTs (4147 women). The quality of evidence ranged from very low to low. The main limitations were imprecision, performance bias, and attrition bias.Hyaluronic acid selected sperm-intracytoplasmic sperm injection (HA-ICSI) compared to ICSITwo RCTs compared the effects of HA-ICSI versus ICSI on live birth. The quality of the evidence was low. There may be little or no difference between groups: 25% chance of live birth with ICSI versus 24.5% to 31% with HA-ICSI (RR 1.09, 95% CI 0.97 to 1.23, 2903 women, I2 = 0%, low-quality evidence). Three RCTs reported on miscarriage. HA-ICSI may decrease miscarriage per woman randomly assigned: 7% chance of miscarriage with ICSI versus 3% to 6% chance with HA-ICSI (RR 0.61, 95% CI 0.45 to 0.83, 3005 women, I2 = 0%, low-quality evidence) and per clinical pregnancy: 20% chance of miscarriage with ICSI compared to 9% to 16% chance with HA-ICSI (RR 0.62, 95% CI 0.46 to 0.82, 1065 women, I2 = 0%, low-quality evidence). Four RCTs reported on clinical pregnancy. There may be little or no difference between groups: 37% chance of pregnancy with ICSI versus 34% to 40% chance with HA-ICSI (RR 1.00, 95% CI 0.92 to 1.09, 3492 women, I2 = 0%, low-quality evidence).HA-ICSI compared to SpermSlowOne RCT compared HA-ICSI to SpermSlow. The quality of the evidence was very low. We are uncertain whether HA-ICSI improves live birth compared to SpermSlow (RR 1.13, 95% CI 0.64 to 2.01, 100 women) or clinical pregnancy (RR 1.05, 95% CI 0.66 to 1.68, 100 women). We are uncertain whether HA-ICSI reduces miscarriage per woman (RR 0.80, 95% CI 0.23 to 2.81, 100 women) or per clinical pregnancy (RR 0.76, 95% CI 0.24 to 2.44, 41 women).Magnetic-activated cell sorting (MACS) compared to ICSIOne RCT compared MACS to ICSI for live birth; three reported clinical pregnancy; and two reported miscarriage. The quality of the evidence was very low. We are uncertain whether MACS improves live birth (RR 1.95, 95% CI 0.89 to 4.29, 62 women) or clinical pregnancy (RR 1.05, 95% CI 0.84 to 1.31, 413 women, I2 = 81%). We are also uncertain if MACS reduces miscarriage per woman (RR 0.95, 95% CI 0.16 to 5.63, 150 women, I2 = 0%) or per clinical pregnancy (RR 0.51, 95%CI 0.09 to 2.82, 53 women, I2=0)Zeta sperm selection compared to ICSIOne RCT evaluated Zeta sperm selection. The quality of the evidence was very low. We are uncertain of the effect of Zeta sperm selection on live birth (RR 2.48, 95% CI 1.34 to 4.56, 203 women) or clinical pregnancy (RR 1.82, 95% CI 1.20 to 2.75, 203 women). We are also uncertain if Zeta sperm selection reduces miscarriage per woman (RR 0.73, 95% CI 0.16 to 3.37, 203 women) or per clinical pregnancy (RR 0.41, 95% CI 0.10 to 1.68, 1 RCT, 62 women).MACS compared to HA-ICSIOne RCT compared MACS to HA-ICSI. This study did not report on live birth. The quality of the evidence was very low. We are uncertain of the effect on miscarriage per woman (RR 1.52, 95% CI 0.10 to 23.35, 78 women) or per clinical pregnancy (RR 1.06, 95% CI 0.07 to 15.64, 37 women). We are also uncertain of the effect on clinical pregnancy (RR 1.44, 95% CI 0.91 to 2.27, 78 women).

AUTHORS' CONCLUSIONS

The evidence suggests that sperm selected by hyaluronic acid binding may have little or no effect on live birth or clinical pregnancy but may reduce miscarriage. We are uncertain of the effect of Zeta sperm selection on live birth, clinical pregnancy, and miscarriage due principally to the very low quality of the evidence for this intervention. We are uncertain of the effect of the other selection techniques on live birth, miscarriage, or pregnancy.Further high-quality studies, including the awaited data from the identified ongoing studies, are required to evaluate whether any of these advanced sperm selection techniques can be recommended for use in routine practice.

Evaluation and improvement of the novel method for vitrification of a few human sperms

RESEARCH QUESTION

The purposes of this study are to evaluate the performance of the novel SpermVD device on vitrification of a few human sperms, and determine whether PICSI dish and density gradient centrifugation can improve the quality of sperm after thawing.

DESIGN AND METHODS

In order to determine the suitable preparation methods, both washed sperm and neat sperm were selected in ICSI dish and PICSI dish, and frozen with the novel SpermVD device. The selected sperms were transferred to freezing droplets with 1 μl droplet of a 50/50 v/v mixture of QA Sperm Freezing Medium and QA Medium w/Hepes on the SpermVD wells. And the device was exposed to vapor of liquid nitrogen for 5 min and then placed into LN₂ immediately. The sperms were thawed in a 37℃ oil filled dish which contained QA Medium w/Hepes droplets and they were searched and revaluated immediately. The frozen effects of sperm were evaluated by progressive motility, motility, viability and recovery rates of freezing-thawing sperm.

RESULTS

After freezing-thawing, the overall sperm recovery rate was 94.2% with 70% viability, 20.7% progressive motility, and 36.2% motility. The progressive motility, motility, viability and recovery rates of washed sperm were lower than that of the neat sperm, with a significant difference (P <  0.01) at both viability and motility rates. In addition, the viability rate was significantly higher in PICSI dish group than that of ICSI dish group (P <  0.01) and the motility, recovery and progressive motility rates were not significantly different between the two groups (P > 0.05).

CONCLUSIONS

The spermVD device was one of the effective platforms for freezing a few human sperms and using PICSI dish to select mature neat sperms could improve the quality of sperm after thawing. Density gradient centrifugation might be not required or suitable sperm preparation methods before freezing.

A successful healthy childbirth and an ongoing evolutive pregnancy in a case of partial globozoospermia by hyaluronic acid sperm selection

We here report a successful healthy childbirth and an ongoing evolutive pregnancy in a case of partial globozoospermia after selection of mature spermatozoa bound to hyaluronic acid (HA). The couple underwent two in vitro fertilisation (IVF) cycles. In the first attempt, 14 MII oocytes were retrieved. Randomly, seven oocytes were injected by conventional PVP-ICSI and seven by HA-ICSI. Fertilised oocytes were 2/7 and 4/7 after PVP-ICSI and HA-ICSI respectively. Transfer of two grade A embryos from HA-ICSI lead to birth of a healthy baby. The surplus embryo of the HA-ICSI group was vitrified at blastocyst stage. The two embryos from PVP-ICSI arrested their development. Two years after the childbirth, the vitrified blastocyst was transferred into the uterus, but implant failed. In the second cycle, 14 MII oocytes were retrieved and they were injected by HA-ICSI. Fertilised oocytes were 10 out of 14 injected oocytes. On day 5, two blastocysts were transferred into uterus and a single evolutive pregnancy is ongoing. On day 6, one blastocyst was vitrified. The remaining surplus embryos arrested their development. A healthy childbirth and an ongoing evolutive pregnancy in two consecutive ICSI attempts of the same couple suggest that HA sperm selection might assist in cases with partial globozoospermia.

An efficiency comparison of different in vitro fertilization methods: IVF, ICSI, and PICSI for embryo development to the blastocyst stage from vitrified porcine immature oocytes

Background

Most studies carried out to evaluate recovery and development after porcine oocyte vitrification, reported better rates when cryopreserved in embryonic development stages or zygotes, but not in immature oocytes. For this reason, many studies are performed to improve immature oocyte vitrification protocols testing the use of different cryoprotectant concentrations, cooling devices, incubation times; but only a few of them have evaluated which fertilization procedure enhances blastocyst rates in vitrified oocytes. Therefore, this study was aimed to evaluate: 1) if the sperm selection with hyaluronic acid (HA) or polyvinylpyrrolidone (PVP) before injection could play a key role in increasing fertilization and blastocyst formation and 2) the embryo developmental ability and blastocyst production of porcine immature oocytes retrieved after vitrification-warming and co-cultured with granulosa cells during IVM, using different fertilization techniques: in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) and conventional ICSI with hyaluronic acid (HA) sperm selection, known as physiological intracytoplasmic sperm injection (PICSI) and.

Results

Sperm selected with HA-PICSI displayed a higher percentage of live/acrosome reacted status compared to those in control and exposed to PVP. Higher dead/acrosome reacted rates were obtained after PVP exposure compared to control and HA. In oocytes, viability significantly decreased after IVM in vitrified oocytes. Besides, IVM rates were not different between control denuded oocytes cultured with granulosa cells (DO-GC) and vitrified oocytes. Regarding fertilization parameters, IVF showed higher percentages of total fertilization rate than those obtained by ICSI and PICSI. However, results demonstrate that PICSI fertilization increased the blastocysts formation rate in control DO-GC and vitrified oocytes compared to IVF and ICSI.

Conclusions

To achieve high blastocyst formation rates from vitrified GV oocytes, it is recommended that sperm should be selected with HA instead of PVP before injection since high viability and acrosome reaction rates were obtained. Also, PICSI fertilization was the best method to produce higher blastocyst rates compared to the IVF and ICSI procedures.

Knowledge gaps in male infertility: a reproductive endocrinology and infertility perspective

Reproductive research has moved forward at a remarkable pace. Some of these advances are the result of a separation between male and female specialties, allowing focused study in specific areas of the field. However, the different training programs between male and female fertility specialists has created an environment in which some discoveries are not put in the greater context of clinical care. At times, interventions have been measured against surrogate markers of outcome that may not impact the most meaningful outcome for patients—the delivery of a healthy neonate. For example, medical and surgical interventions that use changes in semen parameters may have a limited impact on the likelihood of achieving a live birth due to the limitations inherent in the semen analysis for predicting outcomes. Other commonly used tests, such as sperm DNA fragmentation assays provide promising biological plausibility to account for subfertility of some male partners. However, until well defined thresholds for predicting outcomes in different treatment scenarios are available, changes in sperm DNA fragmentation testing is not an adequate outcome for measuring the utility of interventions. The biggest limitation for these tests remains their analysis of bulk semen. Tests allowing interrogation of the reproductive competence of a given sperm, while allowing that sperm to be used in assisted reproductive technology procedures remain elusive. Progress toward reaching this end (whether by hyaluronic acid binding, IMSI, or Ramen spectroscopy) is underway, but much remains to be learned. Achieving testing and capture of individual sperm would better facilitate studies that measure the most meaningful outcome for patients and providers—the delivery of a healthy baby.

Physiological ICSI (PICSI) vs. Conventional ICSI in Couples with Male Factor: A Systematic Review

OBJECTIVES

To determine the efficacy of the physiological ICSI technique (PICSI) vs. conventional ICSI in the prognosis of couples, with respect to the following outcome measures: live births, clinical pregnancy, implantation, embryo quality, fertilization and miscarriage rates.

METHODS

A systematic review of the literature, extracting raw data and performing data analysis. Patient(s): Couples with the male factor, who were subjected to in-vitro fertilization. Main Outcome Measures: rates of live births, clinical pregnancy, implantation, embryo quality, fertilization and miscarriage.

RESULTS

In the systematic search, we found 2,918 studies and an additional study from other sources; only two studies fulfilled the inclusion criteria for this systematic review. The rates of live births, clinical pregnancy, implantation, embryo quality, fertilization and miscarriage were similar for both groups.

CONCLUSION

There is no statistically significant difference between PICSI vs. ICSI, for any of the outcomes analyzed in this study. Enough information is still not available to prove the efficacy of the PICSI technique over ICSI in couples with male factor.

Human sperm handling in intracytoplasmic sperm injection processes: In vitro studies on mouse oocyte activation, embryo development competence and sperm oxidation-reduction potential

Polyvinylpyrrolidone (PVP) and hyaluronic acid (HA) are routinely used in handling spermatozoa for intracytoplasmic sperm injection (ICSI). As there are still concerns about possible adverse effects on the embryo, this study investigated sperm handling in a mouse ICSI model to (i) evaluate oocyte activation after injection of spermatozoa selected for rotational or linear motion in PVP; (ii) assess the effect of sperm selection in PVP, HA and medium on oocyte activation; (iii) examine the effects of PVP and HA on parthenogenetic oocyte activation and embryo development; and (iv) assess the oxidation-reduction potential (ORP) of spermatozoa exposed to PVP, HA or medium. Oocyte activation was higher when spermatozoa exhibited rotational motion rather than linear motion (79% vs. 52%; p = .05). There was no difference in oocyte activation and embryo development after parthenogenetic oocyte activation after sperm injection using PVP, HA or medium-incubated spermatozoa. PVP-selected spermatozoa exhibited lower (p < .0001) ORP levels than using HA. Thus, results indicate that the sperm handling method and the type of medium used impact ICSI outcomes. Overall, sperm incubation in PVP, HA and medium yields similar outcomes with regard to oocyte activation and embryo development. However, PVP provides more antioxidative protection than HA and should therefore be preferred for sperm manipulation.

Hyaluronan-binding system for sperm selection enhances pregnancy rates in ICSI cycles associated with male factor infertility

OBJECTIVES

The aim of the present study was to compare two procedures for sperm selection in ICSI cycles - conventional morphology sperm selection (ICSI-PVP) and chemical selection through Hyaluronan-treated petri dishes (PICSI), when male factor was associated.

METHODS

The evaluated parameters were semen quality, fertilization and cleavage rates, chemical and clinical pregnancy rates, as well as abortion rate. Fifty-six ICSI cycles were included in this report, 19 cycles using PICSI and 37 using conventional ICSI.

RESULTS

PICSI and ICSI showed, respectively, the following outcome: fertilization rates 71.93% (123/171) and 64.14% (127/198); cleavage rates 95.12% (117/123) and 95.27% (121/127); chemical pregnancy rates 63.15% (12/19) and 27.03% (10/37); clinical pregnancy rates 42.10% (8/19) and 16.21% (6/37); and abortion rates 33.33% (4/12) and 40.00% (4/10). According to both Fisher's Exact Test and Chi-square Test, chemical pregnancy (p = 0.05) and clinical pregnancy (p = 0.09) rates were significantly higher in the PICSI group. p values ≤ 0.05 were consider statistically significant.

CONCLUSIONS

The present data indicates that ICSI cycles that used the PICSI technique had a considerably higher chance (≈5 fold) to achieve pregnancy than those who had sperm selected only by morphology assessment. Teratozoospermic patients were those who benefited most with PICSI. Therefore, the technique should be included in laboratory routine with low cost, avoiding the selection of immature sperm with increased rates of peroxidation and DNA fragmentation. Prospective and randomized studies should be applied to strengthen this suggestion.

HBA score in relation to donor semen profiles and live birth rates: a preliminary study

We sought to determine whether sperm donor selection could be improved by using the hyaluronan binding assay (HBA) score to predict live birth rates (LBRs) in donor insemination treatments. Thirty donor samples were included: five fresh samples to assess whether HBA score is affected by cryopreservation and 25 frozen samples from donors whose sperm gave rise to known live births, divided into three groups, with success rates ≥50%, <50-33% and <33%, to examine whether HBA score correlates with LBRs. Correlations with semen analysis parameters, as well as donor demographic factors, known causes of patient subfertility and/or the type of treatment provided were also assessed. There was no significant difference in the mean HBA score pre- and post-cryopreservation (p = 0.998) nor in the HBA score of the three different outcome groups (p = 0.89). HBA score was not significantly affected by other semen analysis parameters (r²=0.394, p = 0.127) or any of the other examined factors. This was the first study to investigate HBA score for cryopreserved donor samples with known LBRs. HBA score was not correlated with LBRs in this small pilot study. Larger studies are required to validate HBA score as a tool for sperm donor selection and predictor of LBRs.

Hyaluronic Acid Binding Sperm Selection for assisted reproduction treatment (HABSelect): study protocol for a multicentre randomised controlled trial

INTRODUCTION

The selection of a sperm with good genomic integrity is an important consideration for improving intracytoplasmic sperm injection (ICSI) outcome. Current convention selects sperm by vigour and morphology, but preliminary evidence suggests selection based on hyaluronic acid binding may be beneficial. The aim of the Hyaluronic Acid Binding Sperm Selection (HABSelect) trial is to determine the efficacy of hyaluronic acid (HA)-selection of sperm versus conventionally selected sperm prior to ICSI on live birth rate (LBR). The mechanistic aim is to assess whether and how the chromatin state of HA-selected sperm corresponds with clinical outcomes-clinical pregnancy rate (CPR), LBR and pregnancy loss (PL).

METHODS AND ANALYSIS

Couples attending UK Centres will be approached, eligibility screening performed and informed consent sought. Randomisation will occur within 24 hours prior to ICSI treatment. Participants will be randomly allocated 1:1 to the intervention arm (physiological intracytoplasmic sperm injection, PICSI) versus the control arm using conventional methods (ICSI). The primary clinical outcome is LBR ≥37 weeks' gestation with the mechanistic study determining LBR's relationship with sperm DNA integrity. Secondary outcomes will determine this for CPR and PL. Only embryologists performing the procedure will be aware of the treatment allocation. Steps will be taken to militate against biases arising from embryologists being non-blinded. Randomisation will use a minimisation algorithm to balance for key prognostic variables. The trial is powered to detect a 5% difference (24-29%: p=0.05) in LBR ≥37 weeks' gestation. Selected residual sperm samples will be tested by one or more assays of DNA integrity.

ETHICS AND DISSEMINATION

HABSelect is a UK NIHR-EME funded study (reg no 11/14/34; IRAS REF. 13/YH/0162). The trial was designed in partnership with patient and public involvement to help maximise patient benefits. Trial findings will be reported as per CONSORT guidelines and will be made available in lay language via the trial web site (http://www.habselect.org.uk/).

TRIAL REGISTRATION NUMBER

ISRCTN99214271; Pre-results.

Improving ICSI: A review from the spermatozoon perspective

Intracytoplasmic sperm injection (ICSI) is the most frequently applied method for fertilization making the process of identifying the perfect spermatozoon fundamental. Herein we offer a critical and thorough presentation on the techniques reported regarding (i) handling and preparing semen samples, (ii) identifying and 'fishing' spermatozoa, and (iii) improving key factors, such as motility for a successful ICSI practice. These approaches are suggested to make the process easier and more effective especially in atypical and challenging circumstances. Furthermore, we present an epigrammatic opinion-where appropriate-based upon our collective experience. Techniques such as intracytoplasmic morphologically selected sperm injection, hyaluronic binding, polarized light microscopy, and annexin V agent identification for comparing sperm cells and their chromatin integrity are analyzed. Moreover, for the demanding cases of total sperm immotility the use of the hypoosmotic swelling test, methylxanthines, as well as the option of laser assisted immotile sperm selection are discussed. Finally, we refer to the employment of myoinositol as a way to bioreactively improve ICSI outcome for oligoasthenoteratozoospermic men. The diversity and the constant development of novel promising techniques to improve ICSI from the spermatozoon perspective, is certainly worth pursuing. The majority of the techniques discussed are still a long way from being established in routine practices of the standard IVF laboratory. In most cases an experienced embryologist could yield the same results. Although some of the techniques show great benefits, there is a need for large scale multicenter randomized control studies to be conducted in order to specify their importance before suggesting horizontal application. Taking into consideration the a priori invasive nature of ICSI, when clinical application becomes a possibility we need to proceed with caution and ensure that in the pursuit for innovation we are not sacrificing safety and the balance of the physiological and biological pathways of the spermatozoon's dynamic.

ABBREVIATIONS

ICSI: intracytoplasmic sperm injection; IVF: in vitro fertilization; PGD: reimplantation genetic diagnosis; IVM: in vitro maturation; HCV/HIV: hepatitis C virus/human immunodeficiency virus; IMSI: intracytoplasmic morphologically selected sperm injection; DGC: density gradient centrifugations; S-U: swim-up; ART: assisted reproduction technology; IUI: intrauterine insemination; PVP: polyvinylpyrrolidone; HA: hyaluronic acid; MSOME: motile sperm organelle morphology examination; ZP: zona pellucida; MACS: magnetic activation cell sorting; HOST: hypo-osmotic swelling test; TESE: testicular sperm extraction; MMP: mitochondrial membrane potential; OAT: oligoasthenoteratozoospermic.

Are there optimal numbers of oocytes, spermatozoa and embryos in assisted reproduction?

The aim of this overview is to discuss the current information about the search for the optimum yield of gametes in assisted reproduction, as one of the major pillars of IVF success. The first topic is focused on the number of male gametes and the possible impact of some genetic traits on these parameters. The number of spermatozoa did not seem to be crucial when there is no severe male factor of infertility. Genetic testing prior to using those sperm cells is very important. Different methods were applied in order to elect the "best" spermatozoa according to specific indications. The next problem discussed is the importance of the number of oocytes collected. Several studies have agreed that "15 oocytes is the perfect number," as the number of mature oocytes is more important. However, if elective single embryo transfer is performed, the optimal number of oocytes will enable a proper embryo selection. The third problem discussed concerns fertility preservation. Many educational programs promote and encourage procreation at maternal ages between 20-35 years, since assisted reproduction is unable to fully overcome the effects of female aging and fertility loss after that age. It is also strongly recommended to ensure a reasonable number of cryopreserved mature oocytes, preferably in younger ages (<35), for which an average of two stimulation cycles are likely required. For embryo cryopreservation, the "freeze all" strategy suggests the vitrification of good embryos, therefore quality is prior to number and patient recruitment for this strategy should be performed cautiously.

Sperm selection in natural conception: what can we learn from Mother Nature to improve assisted reproduction outcomes?

BACKGROUND

In natural conception only a few sperm cells reach the ampulla or the site of fertilization. This population is a selected group of cells since only motile cells can pass through cervical mucus and gain initial entry into the female reproductive tract. In animals, some studies indicate that the sperm selected by the reproductive tract and recovered from the uterus and the oviducts have higher fertilization rates but this is not a universal finding. Some species show less discrimination in sperm selection and abnormal sperm do arrive at the oviduct. In contrast, assisted reproductive technologies (ART) utilize a more random sperm population. In this review we contrast the journey of the spermatozoon in vivo and in vitro and discuss this in the context of developing new sperm preparation and selection techniques for ART.

METHODS

A review of the literature examining characteristics of the spermatozoa selected in vivo is compared with recent developments in in vitro selection and preparation methods. Contrasts and similarities are presented.

RESULTS AND CONCLUSIONS

New technologies are being developed to aid in the diagnosis, preparation and selection of spermatozoa in ART. To date progress has been frustrating and these methods have provided variable benefits in improving outcomes after ART. It is more likely that examining the mechanisms enforced by nature will provide valuable information in regard to sperm selection and preparation techniques in vitro. Identifying the properties of those spermatozoa which do reach the oviduct will also be important for the development of more effective tests of semen quality. In this review we examine the value of sperm selection to see how much guidance for ART can be gleaned from the natural selection processes in vivo.

Microfluidic assessment of swimming media for motility-based sperm selection

Selection medium is important in sperm isolation for assisted reproductive technologies. Contrary to the naturally occurring human cervical mucus which has a high viscosity, most current practices for motility based sperm selection use a low viscosity medium. In this study, we used a microfluidic device to assess the effects of high viscosity media made with hyaluronic acid (HA) and methyl cellulose (MC) on bovine and human sperm motility and viability (sperm transferred directly from cryoprotectant). The microfluidic penetration test, viability, and motility were compared for sperm swimming in both HA and MC media with about 20cp viscosity (measured at 20 °C). Our resulted indicate that MC medium resulted in a significantly higher number of viable bovine sperm penetrating the medium as compared to HA. Furthermore, MC resulted in the selection of a sperm subpopulation with a 274% increase in sperm viability in comparison to the raw semen, while HA increased viability by only 133%. In addition to viability, bovine sperm motility parameters were significantly higher in the MC medium as compared with HA. Experiments with human sperm swimming in MC indicate that sperm swim slower and straighter at higher viscosities. In conclusion, the results indicate that in a micro-confined environment representative of the in vivo environment, MC is a preferred high viscosity medium to ensure the highest concentration of motile and viable sperm.

Advanced sperm selection techniques for assisted reproduction

BACKGROUND

Assisted reproductive technologies (ART) such as in vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI) bring together gametes outside of the body to enhance the probability of fertilisation and pregnancy. Advanced sperm selection techniques are increasingly being employed in ART, most commonly in cycles utilising ICSI. Advanced sperm selection techniques are thought to improve the chance that structurally intact and mature sperm with high DNA integrity are selected for fertilisation. Advanced sperm selection strategies include selection according to surface charge; sperm apoptosis; sperm birefringence; ability to bind to hyaluronic acid; and sperm morphology under ultra-high magnification. These techniques theoretically improve ART outcomes.

OBJECTIVES

To evaluate the impact of advanced sperm selection techniques on ART outcomes.

SEARCH METHODS

Systematic search of electronic databases (Cochrane Menstrual Disorders and Subfertility Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, PsycINFO, Cumulative Index to Nursing and Allied Health Literature (CINAHL), Latin American and Caribbean Health Science Information Database (LILACS)), trials registers (ClinicalTrials.gov, Current Controlled Trials, World Health Organization International Clinical Trials Registry Platform), conference abstracts (Web of Knowledge) and grey literature (OpenGrey) for relevant randomised controlled trials. We handsearched the reference lists of included studies and similar reviews. The search was conducted in May 2014.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing an advanced sperm selection technique versus standard IVF or ICSI or versus another advanced sperm selection technique. We excluded studies of sperm selection using ultra-high magnification (intracytoplasmic morphologically selected sperm injection, or IMSI), as they are the subject of a separate Cochrane review. Quasi-randomised and pseudo-randomised trials were excluded. Our primary outcome measure was live birth rate per woman randomly assigned. Secondary outcome measures included clinical pregnancy per woman randomly assigned, miscarriage per clinical pregnancy and fetal abnormality per clinical pregnancy.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility of studies and risk of bias, and performed data extraction. Disagreements were resolved by consultation with a third review author. Study investigators were consulted to resolve other queries that arose. Risk ratios (RRs) were calculated with 95% confidence intervals (CIs). We planned to combine studies using a fixed-effect model, if sufficient data were available. The quality of the evidence was evaluated using Grades of Recommendation, Assessment, Development and Evaluation (GRADE) methods.

MAIN RESULTS

Two RCTs were included in the review. Both evaluated sperm selection by hyaluronanic acid binding for ICSI, but only one reported live births. No studies were identified that were related to surface charge selection, sperm apoptosis or sperm birefringence.One RCT compared hyaluronanic acid binding versus conventional ICSI. Live birth was not reported. Evidence was insufficient to show whether there was a difference between groups in clinical pregnancy rates (RR 1.01, 95% CI 0.84 to 1.22, one RCT, 482 women). This evidence was deemed to be of low quality, mainly as the result of poor reporting of methods and findings. Miscarriage data were unclear, and fetal abnormality rates were not reported.The other RCT compared two different hyaluronanic acid binding techniques, SpermSlow and physiological intracytoplasmic sperm injection (PISCI). Evidence was insufficient to indicate whether there was a difference between groups in rates of live birth (RR 1.16, 95% CI 0.65 to 2.05, one RCT, 99 women), clinical pregnancy (RR 1.07, 95% CI 0.67 to 1.71, one RCT, 99 women) or miscarriage (RR 0.76, 95% CI 0.24 to 2.44, one RCT, 41 women). The evidence for these comparisons was deemed to be of low quality, as it was limited by imprecision and poor reporting of study methods. Fetal abnormality rates were not reported.

AUTHORS' CONCLUSIONS

Evidence was insufficient to allow review authors to determine whether sperm selected by hyaluronanic acid binding improve live birth or pregnancy outcomes in ART, and no clear data on adverse effects were available. Evidence was also insufficient to show whether there is a difference in efficacy between the hyaluronic acid binding methods SpermSlow and PICSI. No randomised evidence evaluating sperm selection by sperm apoptosis, sperm birefringence or surface charge was found.Further studies of suitable quality are required to evaluate whether any of these advanced sperm selection techniques can be recommended for use in clinical practice.

Rapid selection of sperm with high DNA integrity

Sperm selection is essential to assisted reproductive technology (ART), influencing treatment outcomes and the health of offspring. The fundamental challenge of sperm selection is dictated by biology: a heterogeneous population of ~10(8) sperm per milliliter with a short lifetime in vitro. However, conventional sperm selection approaches result in less than 50% improvement in DNA integrity. Here, a clinically applicable microfluidic device is presented that selects sperm based on the progressive motility in 500 parallel microchannels. The result is a one-step procedure for semen purification and high DNA integrity sperm selection from 1 mL of raw semen in under 20 minutes. Experiments with bull sperm indicate more than 89% improvement in selected sperm vitality. Clinical tests with human sperm show more than 80% improvement in human DNA integrity, significantly outperforming the best current practices. These results demonstrate the presence of a sub-population of sperm with nearly intact chromatin and DNA integrity, and a simple clinically-applicable lab-on-a-chip method to select this population.

Sperm selection: effect on sperm DNA quality

The selection of spermatozoa without DNA fragmentation and chromosomal diseases prior to assisted reproductive techniques helps to optimize the outcome of the treatment; in particular, sperm selection prior to in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) is crucial. In fact, although ICSI has been successfully and safely applied worldwide for almost 20 years, at the present time we have no real knowledge regarding the hypothetical long-term side effects on ICSI adults, given the increased likelihood of spermatozoa with defective nuclear content fertilizing oocytes.In the case of DNA damage, the basal sperm DNA fragmentation rate can be significantly reduced by some sperm processing procedures that improve the percentage of spermatozoa with normal chromatin structure by filtering out DNA-damaged spermatozoa. After this first step, new advances in micromanipulation can be performed to choose the "ideal" mature spermatozoa for ICSI, reducing potential damage to the gametes. In fact, it is possible to prevent fertilization by DNA-damaged and chromosomal-unbalanced spermatozoa by selecting ICSI sperm by maturation markers such as hyaluronic acid or other zona pellucida receptors. Furthermore, novel noninvasive imaging techniques can be valid tools for helping in the morphological selection of ICSI spermatozoa.

A prospective randomized study to evaluate the effect of hyaluronic acid sperm selection on the intracytoplasmic sperm injection outcome of patients with unexplained infertility having normal semen parameters

PURPOSE

Sperm quality plays an important role in determining embryo development and intracytoplasmic sperm injection (ICSI) outcome. Selection of competent sperm based on its ability to bind to hyaluronic acid (HA) has been suggested as one of the methods to assess sperm quality. The aim of the present study was to examine whether injection of HA bound sperm helps in improving outcome in patients undergoing ICSI with unexplained infertility having normal semen parameters.

METHODS

Patients with unexplained infertility having normal semen parameters in accordance with WHO 2010 criterion, undergoing their first IVF-ICSI cycle were enrolled during the course of the study.156 patients were prospectively randomized after oocyte retrieval and were assigned to either the ICSI group, where sperm selection for injection was based on visual assessment, or the PICSI group, where sperm were selected based on their ability to bind to HA. Only fresh embryo transfers were included in the analysis.

RESULTS

There was no difference in the fertilization rates, number of top quality embryos and clinical pregnancy rates between the ICSI and PICSI groups (65.7 % vs 64.7 %; 45.8 % vs 43.6 % and 35 % vs 35.2 % respectively). However, a higher pregnancy loss rate was observed in the ICSI group (25 % vs 12 %; P = 0.227) as compared to the PICSI group, but the difference was not statistically significant. Implantation rates were 22.03 % and 18.84 % in the PICSI and ICSI groups respectively. There were 22 (31 %) live births in the PICSI group and 21(26.3 %) live births in the ICSI group.

CONCLUSIONS

Patients with unexplained infertility having normal semen parameters may constitute a patient group which does not benefit from this sperm selection method. A larger study may be necessary to establish a relationship between PICSI and pregnancy loss rate in patients undergoing IVF with unexplained infertility.

Relationship between Sperm Hyaluronan-Binding Assay (HBA) Scores on Embryo Development, Fertilisation, and Pregnancy Rate in Patients Undergoing Intra-Cytoplasmic Sperm Injection (ICSI)

Introduction:

The novel development of the sperm hyaluronan-binding assay (HBA) has now been routinely used in some laboratories worldwide to predict sperm maturity and functionality. Hence, the purpose of this study is to evaluate if embryo development, quality, fertilisation and pregnancy rates are affected by low HBA values.

Methods:

A total of192 female patients who underwent intra-cytoplasmic sperm injection (ICSI) were compared retrospectively in terms of embryo development, fertilisation, and pregnancy rates with their husbands' HBA score. Patients' husbands were required to undergo a HBA test before the start of their stimulation cycle to determine if their semen was suitable to undergo ICSI or in-vitro fertilisation (IVF). P-value < 0.05 was considered significant.

Results:

Patients were divided into four groups, group A (HBA ≤ 15%), group B (HBA > 15% < 35%), group C (HBA ≥ 35% < 60%), and group D (HBA ≥ 60%). The fertilisation rate for groups A, B, C, and D were 67.9%, 73.1%, 72.5%, and 77.1% respectively. Group D had a fertilisation rate significantly higher than the rest of the groups ( p = 0.016). The pregnancy rate for group D was also significantly higher amongst the four groups ( p = 0.041), whereas the pregnancy rate for groups B and C was similar (42.4% versus 41.1% respectively). Day three cleavage rate (the ability to reach six cells and beyond) was highest for group D compared to the other groups ( p = 0.002).

Conclusion:

The higher the HBA score, the better the fertilisation, pregnancy, and cleavage rates. This shows that HBA does have the ability to select mature sperms with normal chromosome development and oocyte-binding capability.

Novel technologies for selecting the best sperm for in vitro fertilization and intracytoplasmic sperm injection

The increasing focus on developing new tools to more accurately diagnose and select individual sperm before intracytoplasmic sperm injection will allow us to counsel and treat couples with greater confidence and efficiency. Current sperm selection techniques are based on the premise that if an ejaculated spermatozoon has cleared spermatogenesis with the correct morphology and/or membrane properties then it is most likely normal. Techniques that are designed to prepare a clean "normal" sperm population or that assist in selecting an individual "normal" spermatozoon are currently being investigated. The use of techniques, including density-gradient preparation, electrophoretic separation, microfluidics, high-magnification sperm morphology selection, and hyaluronic acid binding, is discussed. The research evidence that supports the interrelated developmental and genetic integrity of the selected sperm, particularly sperm DNA damage and clinical outcome evidence are presented.

Application of sperm selection using hyaluronic acid binding in intracytoplasmic sperm injection cycles: a sibling oocyte study

The purpose of this study was to investigate whether sperm selection by hyaluronic acid (HA) binding could improve fertilization rate and embryo quality in intracytoplasmic sperm injection (ICSI) cycles. Two hundred nineteen oocytes obtained from eighteen women were injected with either HA-bound (n = 107) or conventionally selected spermatozoa (n = 112) in a randomized way. All of the participants were infertile couples who had normal sperm parameters but low fertilization rate in previous in vitro fertilization (IVF) cycle (n = 5) or experienced multiple IVF failures (n = 13). Lower fertilization (75.7% vs 83.0%) and cleavage rate on day 2 (72.9% vs 83.0%) was observed in oocytes injected with HA-bound spermatozoa than the conventional group, but the difference was not significant. Significantly lower cleavage rate was observed on day 3 in HA group (56.0% vs 69.6%, P = 0.038). Blastocyst formation rate and the number of transferred embryos were similar in both groups. In multiple IVF failure patients, significantly reduced fertilization rate (71.8% vs 85.3%, P = 0.046) and cleavage rate on day 2 (70.4% vs 85.3%, P = 0.029) and day 3 (53.5% vs 77.3%, P = 0.002) were noticed in HA group. Five women achieved pregnancy continuing more than 12 weeks after transfer (27.8%). Success of ICSI was not related with the number of embryos fertilized by HA-bound spermatozoa. Application of ICSI by sperm selection using HA binding is not helpful in couples with repeated poor fertilization or implantation despite normal sperm parameters.