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

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.

Resolving Secondary Infertility: A Case Report of the Successful Treatment of Sperm DNA Fragmentation Through the Physiological Intracytoplasmic Sperm Injection Method

This case report presents an illustrative account of a couple experiencing secondary infertility attributed to the fragmentation of DNA in sperm. Secondary infertility, the inability to conceive after having previously successfully conceived a child, can be due to various factors, including male infertility issues. Sperm DNA fragmentation (SDF) has emerged as a major factor influencing male fertility, resulting in poor embryo development and lower pregnancy rates. This case is about the use of advanced assisted reproductive technologies, specifically physiological intracytoplasmic sperm injection (PICSI) and intracytoplasmic sperm injection (ICSI), to treat secondary infertility caused by fragmentation of sperm DNA. PICSI enables the identification and selection of spermatozoa with optimal functional integrity using hyaluronan, a natural binding substance. Preparing a PICSI dish requires skill and precision. Sperm exhibiting a high DNA fragmentation index were excluded from the selection process to enhance embryo development potential. The couple underwent controlled ovarian stimulation, egg retrieval, and ICSI with PICSI. The treatment resulted in the successful conception of a singleton pregnancy. Subsequent prenatal monitoring indicated a healthy pregnancy progression, ultimately culminating in the delivery of a healthy baby girl at term. This case report highlights the efficacy of integrating PICSI as a sperm selection method preceding ICSI, specifically in cases of secondary infertility related to SDF. Further research and larger-scale studies are warranted to approve the findings of this case report and establish the broader applicability of this treatment approach.

Qualified sperm selection based on the rheotaxis and thigmotaxis in a microfluidic system

Microfluidic systems with the ability to mimic the female reproductive tract (FRT) and sperm features have emerged as promising methods to separate sperm with higher quality for the assistant reproductive technology. Thereby, we designed and fabricated a microfluidic system based on FRT features with a focus on rheotaxis and thigmotaxis for passive sperm separation. In this regard, four various geometries (linear, square, zigzag, and sinusoidal) were designed, and the effect of rheotaxis and thigmotaxis were investigated. Although separated sperm in all microchannels were 100% motile, non-linear geometries were more effective than linear geometry in the term of separating the progressive sperm with high quality. In the presence of upstream flow, periodical changes in the slope of walls (in non-linear geometries) give rise to the periodical facing sperm with a high flow rate in the middle of microchannels, which was a reason for the high quality of separated sperm. However, because of sharp corners in the square and zigzag microchannels that create dead zones with a lack of upstream flow, which is noticeable via simulation results, these geometries have obstacles against sperm swimming toward the outlet, which was proved by image analysis. The sinusoidal geometry showed the highest enhancement level of the designed geometries compared to the linear geometry. Separated sperm exhibited 34.7% normal morphology, 100% motility, and 100% viability in the sinusoidal geometry. Therefore, the periodic change in the position of sperm from one wall to another wall can be a strategy for separating sperm with high quality.

Graphical abstract

In the present study, we used a microfluidic system for studying the combined effects of thigmotaxis and rheotaxis for sperm separation process to achieve the successful Assisted reproductive technology (ART). The designed PDMS-based microfluidic system had four various geometries, including linear, square, zigzag, and sinusoidal. The functionality of separated sperm was evaluated by sperm tracking (ImageJ), motility assay (CASA software), and morphology assay (Papanicolaou ultrafast staining). Probing various geometries revealed 100% motility. In non-linear geometries, sperm's periodic detachment from the walls gave rise to the periodic interaction with the high flow velocity in the center of the channel, resulting in the separation of high-quality sperm with progressive motility. The collected data proved the influence of thigmotaxis on the quality of separated sperm. Morphologically improvement in separated sperm from the sinusoidal geometry was significant than others, which means the sinusoidal structure would be the best candidate for the sperm separation process.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13534-023-00294-8.

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 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.

The efficacy of add-ons: selected IVF "add-on" procedures and future directions

Since the advent of ART, technology has continuously evolved to improve embryology and pregnancy outcomes. However, not all technologies that are integrated into practice have convincing evidence of clinical effectiveness, and they often increase the financial burden of fertility care. We discuss here a selection of commonly utilized IVF "add-ons" and discuss the existing evidence for their utility. The procedures included in this review are time-lapse imaging of embryos, assisted hatching, EmbryoGlue, sperm DNA testing, egg activation with calcium ionophore, endometrial receptivity array, and physiological intracytoplasmic sperm injection (PICSI). While there is rather limited supporting evidence for nearly all IVF add-ons that we reviewed, there is strong demand from patients, physicians, and the biotechnology industry to continue further research and development in this arena. We propose that all add-on procedures should provide true efficacy for the patient, and reproductive endocrinologists should inform patients of the costs and benefits of utilizing various technologies before they undergo treatment. In the future, add-ons that show clear evidence of efficacy and justifiable cost should be incorporated into routine practice, while others that do not meet these criteria should be phased out entirely.

Simulating nature in sperm selection for assisted reproduction

Sperm selection in the female reproductive tract (FRT) is sophisticated. Only about 1,000 sperm out of millions in an ejaculate reach the fallopian tube and thus have a chance of fertilizing an oocyte. In assisted reproduction techniques, sperm are usually selected using their density or motility, characteristics that do not reflect their fertilization competence and, therefore, might result in failure to fertilize the oocyte. Although sperm processing in in vitro fertilization (IVF) and intrauterine insemination (IUI) bypasses many of the selection processes in the FRT, selection by the cumulus mass and the zona pellucida remain intact. By contrast, the direct injection of a sperm into an oocyte in intracytoplasmic sperm injection (ICSI) bypasses all natural selection barriers and, therefore, increases the risk of transferring paternal defects such as fragmented DNA and genomic abnormalities in sperm to the resulting child. Research into surrogate markers of fertilization potential and into simulating the natural sperm selection processes has progressed. However, methods of sperm isolation - such as hyaluronic acid-based selection and microfluidic isolation based on sperm tactic responses - use only one or two parameters and are not comparable with the multistep sperm selection processes naturally occurring within the FRT. Fertilization-competent sperm require a panel of molecules, including zona pellucida-binding proteins and ion channel proteins, that enable them to progress through the FRT to achieve fertilization. The optimal artificial sperm selection method will, therefore, probably need to use a multiparameter tool that incorporates the molecular signature of sperm with high fertilization potential, and their responses to external cues, within a microfluidic system that can replicate the physiological processes of the FRT in vitro.

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.

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.

Prediction of DNA Integrity from Morphological Parameters Using a Single-Sperm DNA Fragmentation Index Assay

Intracytoplasmic sperm injection is a popular form of in vitro fertilization, where single sperm are selected by a clinician and injected into an egg. Whereas clinicians employ general morphology-based guidelines to select the healthiest-looking sperm, it remains unclear to what extent an individual sperm's physical parameters correlate with the quality of internal DNA cargo-a measurement that cannot be obtained without first damaging the sperm. Herein, a single-cell DNA fragmentation index (DFI) assay is demonstrated, which combines the single-cell nature of the acridine orange test with the quantitative aspect of the sperm chromatin structure assay, to create a database of DFI-scored brightfield images. Two regression predictive models, linear and nonlinear regression, are used to quantify the correlations between individual sperm morphological parameters and DFI score (with model test r at 0.558 and 0.620 for linear and nonlinear regression models, respectively). The sample is also split into two categories of either relatively good or bad DFIs and a classification predictive model based on logistic regression is used to categorize sperm, resulting in a test accuracy of 0.827. Here, the first systematic study is presented on the correlation and prediction of sperm DNA integrity from morphological parameters at the single-cell level.

Physiological, hyaluronan-selected intracytoplasmic sperm injection for infertility treatment (HABSelect): a parallel, two-group, randomised trial

BACKGROUND

Sperm selection strategies aimed at improving success rates of intracytoplasmic sperm injection (ICSI) include binding to hyaluronic acid (herein termed hyaluronan). Hyaluronan-selected sperm have reduced levels of DNA damage and aneuploidy. Use of hyaluronan-based sperm selection for ICSI (so-called physiological ICSI [PICSI]) is reported to reduce the proportion of pregnancies that end in miscarriage. However, the effect of PICSI on livebirth rates is uncertain. We aimed to investigate the efficacy of PICSI versus standard ICSI for improving livebirth rates among couples undergoing fertility treatment.

METHODS

This parallel, two-group, randomised trial included couples undergoing an ICSI procedure with fresh embryo transfer at 16 assisted conception units in the UK. Eligible women (aged 18-43 years) had a body-mass index of 19-35 kg/m² and a follicle-stimulating hormone (FSH) concentration of 3·0-20·0 mIU/mL or, if no FSH measurement was available, an anti-müllerian hormone concentration of at least 1·5 pmol/L. Eligible men (aged 18-55 years) had not had a vasovasostomy or been treated for cancer in the 24 months before recruitment and were able, after at least 3 days of sexual abstinence, to produce freshly ejaculated sperm for the treatment cycle. Couples were randomly assigned (1:1) with an online system to receive either PICSI or a standard ICSI procedure. The primary outcome was full-term (≥37 weeks' gestational age) livebirth, which was assessed in all eligible couples who completed follow-up. This trial is registered, number ISRCTN99214271.

FINDINGS

Between Feb 1, 2014, and Aug 31, 2016, 2772 couples were randomly assigned to receive PICSI (n=1387) or ICSI (n=1385), of whom 2752 (1381 in the PICSI group and 1371 in the ICSI group) were included in the primary analysis. The term livebirth rate did not differ significantly between PICSI (27·4% [379/1381]) and ICSI (25·2% [346/1371]) groups (odds ratio 1·12, 95% CI 0·95-1·34; p=0·18). There were 56 serious adverse events in total, including 31 in the PICSI group and 25 in the ICSI group; most were congenital abnormalities and none were attributed to treatment.

INTERPRETATION

Compared with ICSI, PICSI does not significantly improve term livebirth rates. The wider use of PICSI, therefore, is not recommended at present.

FUNDING

National Institute for Health Research Efficacy and Mechanism Evaluation Programme.

Fibronectin as a new biomarker for human sperm selection in assisted reproductive technology

OBJECTIVE

Fibronectin (FN) is a multifunctional diametric glycoprotein on the surface of the sperm that plays an important role in the sperm-oocyte interaction and fertilization process. The aim of the present study was to assess the FN levels as a sperm surface biomarker for sperm selection in assisted reproductive technology.

MATERIAL AND METHODS

Polyclonal antibody against human FN was produced in rabbit. Its quality, purity, and immune reactivity were assessed by SDS-PAGE and western blot. In addition, the presence of FN on the sperm surface was assessed through immunocytochemistry and flow cytometry. The amount of FN and the sperm quality were assessed in normozoospermia (N) (42 men) and asthenoteratozoospermia (AT) (72 men) groups through sperm chromatin dispersion (SCD), sperm chromatin structure assay (SCSA), and chromatin maturation index (CMI).

RESULTS

The results showed the distribution of FN protein on the equatorial region of the human sperm surface. In addition, the FN levels were found to have a significant difference between the two groups with 24.64±9.08% in N and 16.90±7.27% in AT (p≤0.0001). In addition, FN level negatively correlated with SCD (p≤0.0001), SCSA (p≤0.0001), and CMI (p≤0.001). Threshold values of FN level and DNA fragmentation index (DFI) percentage were 16 and 30 and were identified as cut-off values to determine the N group with a specificity of 83.3% and 81.0% and a sensitivity of 16.8% and 19.0%, respectively. The specificity and sensitivity of FN-DFI were 91.2% and 8.8%, respectively.

CONCLUSION

It appears that FN can be used for the selection of sperm with suitable quality, although future studies are recommended.

Investigating the Glycating Effects of Glucose, Glyoxal and Methylglyoxal on Human Sperm

Glycation is the non-enzymatic reaction between reducing sugars, such as glucose, and proteins, lipids or nucleic acids, producing Advanced Glycation End (AGE) products. AGEs, produced during natural senescence as well as through lifestyle factors such as diet and smoking, are key pathogenic compounds in the initiation and progression of diabetes. Importantly, many of these factors and conditions also have influence on male fertility, affecting sperm count and semen quality, contributing to the decreasing trend in male fertility. This study investigated the impact of AGEs on sperm damage. In vitro sperm glycation assays were used to determine the levels and localization of the potent AGE compound, carboxymethyl-lysine (CML) in response to treatment with the glycating compounds glucose, glyoxal and methylglyoxal. Sperm function assays were then used to assess the effects of glycation on motility and hyaluronan binding, and levels of oxidative DNA damage were analyzed through measurement of the marker, 8-oxoguanine. Results showed that glyoxal, but not glucose or methylglyoxal, induced significant increases in CML levels on sperm and this correlated with an increase in 8-oxoguanine. Immunocytochemistry revealed that AGEs were located on all parts of the sperm cell and most prominently on the head region. Sperm motility and hyaluronidase activity were not adversely affected by glycation. Together, the observed detrimental effects of the increased levels of AGE on DNA integrity, without an effect on motility and hyaluronidase activity, suggest that sperm may retain some fertilizing capacity under these adverse conditions.