Influence of the abstinence period on human sperm quality: analysis of 2,458 semen samples

Association between penultimate ejaculatory abstinence and sperm quality: a cross-sectional study

Background

Ejaculatory abstinence (EA) duration influences semen parameters. However, the impact of penultimate ejaculatory abstinence (PEA) on conventional and functional sperm parameters remains underexplored.

Method

A cross-sectional study recruited 1,503 men from a reproductive center between November 2023 and July 2024. Each participant underwent a physical examination, completed clinical questionnaires, and provided a semen sample for analysis. Generalized linear models were adjusted for potential confounders such as EA to investigate the association between PEA and various sperm parameters. Logistic regression was used to evaluate the relationship between PEA and the risk of high sperm DNA fragmentation index (DFI), oligozoospermia, asthenozoospermia, and necrozoospermia.

Results

Participants were categorized into four quartiles based on PEA duration. (Q1: 1-3 days; Q2: 4-5 days; Q3: 6-9 days; Q4: > 9 days). After adjusting for potential confounders, a significant positive linear association was found between PEA and DFI, while a significant negative linear association was observed with progressive sperm motility. The longest PEA duration (Q4) correlated positively with semen concentration (P = 0.025), total sperm count (P < 0.001), and sperm vitality (P < 0.001). Compared to Q1, a PEA of > 9 days (Q4) was associated with higher risks of sperm DFI > 30% (adjusted odds ratio [OR] = 4.25; 95% confidence interval [CI]: 2.37-7.62), asthenozoospermia (adjusted OR = 1.45; 95% CI: 1.07-1.96), and necrozoospermia (adjusted OR = 1.99; 95% CI: 1.07-3.69). Moreover, the risk of sperm DFI > 15% was higher in Q2, Q3, and Q4 compared to Q1.

Conclusion

Prolonged PEA adversely affects sperm DFI, progressive motility, and sperm vitality, increasing the likelihood of asthenozoospermia, necrozoospermia, and elevated DFI levels. These findings suggest that both EA and PEA should be considered in fertility assessments, with shorter PEA durations potentially yielding higher quality sperm, thereby enhancing male fertility evaluation and outcomes.

Impact of short abstinence versus testicular sperm on sperm DNA fragmentation: a systematic review and meta-analysis

PURPOSE

Optimal sperm DNA integrity is essential for fertilization and embryo health. Research indicates that testicular sperm (TS), obtained via TESA or TESE, typically show lower sperm DNA fragmentation (SDF) than ejaculated sperm after standard abstinence. Shortening abstinence to less than 2 days might reduce SDF, offering a less invasive and more cost-effective alternative to surgical sperm retrieval. Yet, no studies have directly compared the efficacy of shorter abstinence against TS extraction for lowering SDF. Our meta-analysis aims to address this gap by comparing SDF levels in TS to those in ejaculated sperm after a short abstinence period.

METHODS

Meta-analysis of 16 randomized controlled and prospective observational studies included 4 on TS and 12 on short abstinence ejaculation. The meta-analysis followed MOOSE guidelines, scrutinizing databases including Cochrane Library, Web of Science, Embase, MEDLINE(R), and PUMBED up to November 16, 2023. The analysis was conducted using RevMan. The observational studies' methodological quality was assessed using the Newcastle-Ottawa Scale, and the overall evidence quality was evaluated following the GRADE criteria. To compare short ejaculation duration and TS (are not directly compared in the literature) for SDF levels, we analyzed relevant data from studies of each method. We adjusted the participant numbers in the TS group by 1/3 and included each TS study three times, to perform a comparison against the short duration studies which were in a ratio of 1:3. This approach maintained an unaltered cumulative subject count for the meta-analysis of TS studies.

RESULTS

A total of 641 patients were included, comprising 120 and 521 patients with SDF measurements following TS and ejaculation after a short abstinence period, respectively. The studies had varied inclusion criteria, with not all patients having an initial elevated SDF. Some studies had incomplete details on age and other demographics. However, the mean ± SD age of 93 TS patients was 38.15 ± 5.48 years vs. 37.7 ± 6.0 years of 444 short abstinence patients, demonstrating no significant difference (P = 0.544). Short abstinence durations ranged from 1 to 48 h. Diverse DNA fragmentation tests were used: TUNEL assay in three testicular sperm studies, SCD assay in one, and in the short abstinence group, four used TUNEL and six used SCD assays, along with one each using SCSA and Halosperm. The mean ± SD SDF was lower in the TS group than in the short abstinence group (mean difference - 9.48, 95%CI - 12.45 to - 6.52, P < 0.001, I2 = 85%). Sensitivity analysis revealed that no single study significantly influenced the results. Employing the GRADE criteria, the initial assessment categorized the overall quality of evidence as low due to the observational nature of the acquired data. All studies were of medium to high quality.

CONCLUSION

This study suggests testicular sperm may be better than ejaculated sperm for improving SDF in infertility cases. Direct comparisons are needed, before deeming short abstinence less effective. Future research should directly compare reproductive outcomes using both methods.

Effects of long and short ejaculatory abstinence on sperm parameters: a meta-analysis of randomized-controlled trials

Purpose

This study aimed to investigate the effects of ejaculatory abstinence on sperm parameters.

Methods

This analysis was registered in PROSPERO (CRD42023472124). We performed a search on PubMed using the following text terms: (("sperm parameters" OR "sperm analysis" [Mesh]) AND ("sperm DNA fragmentation" OR "DNA fragmentation" [Mesh]) AND ("sexual abstinence" [Mesh] OR "abstinence")) and an advanced search in Scopus using the terms ("sperm parameters" OR "sperm parameters" OR "DNA fragmentation") AND ("abstinence"). The sperm parameters that were investigated were sperm volume, total sperm motility, progressive sperm motility, sperm concentration, sperm morphology, and sperm DNA fragmentation (SDF). A two-day cut-off as a "short" or "long" abstinence period has been defined.

Results

Thirteen studies published between 2013 and 2022 were included in this meta-analysis. A total of 2,315 patients, ranging from 6 to 836 from each cohort, were enrolled in the study. We showed that longer abstinence time was associated with greater sperm concentration (mean difference [MD]: 8.19; p <0.01), sperm volume (MD: 0.96; p <0.01), and higher SDF (MD: 3.46; p <0.01), but lower progressive sperm motility (MD: -1.83; p <0.01). Otherwise, no statistically significant difference was observed in patients with longer vs. shorter abstinence times regarding total sperm motility (MD: -1.83; p = 0.06). Meta-regression analysis showed that days of abstinence were positively and linearly related to sperm concentration (slope: 3.74; p <0.01) and SDF (slope: 0.65; p = 0.044).

Conclusions

According to our data, short ejaculatory abstinence is associated with better sperm quality. Indeed, a higher percentage of progressive sperm motility and lower levels of SDF have been reported in a short abstinence cohort. In contrast, the long abstinence group reported a higher sperm concentration.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023472124.

Comparative developmental competence of in vitro embryos recovered from Bali cattle with normal and poor sperm motility

Background and Aim

Fertility is crucial for enhancing the efficiency of livestock production, as it directly impacts the reproductive rates. A comprehensive understanding of the relationship between sperm quality and embryo development is key to optimizing reproductive outcomes and improving the quality of livestock. This study analyzed the developmental competence of in vitro embryos recovered from Bali cattle with normal or poor sperm motility.

Materials and Methods

Nine bulls with normal fresh semen (NFS) or poor fresh semen (PFS) motility were ejaculated for semen. Semen ejaculates, including volume, motility, and sperm concentration, were evaluated immediately after collection to measure the quality of the fresh semen. Frozen semen was evaluated using computer-assisted semen analysis (CASA) for motility, progressive sperm motility, distance curve path, distance curve linear, distance straight line, average path velocity, curvilinear velocity, linear velocity, straightness (STR), linearity of forward progression (LIN), wobble, and average lateral head displacement (ALH). Bull groups were used to determine in vitro embryo cleavage ability after fertilization of Bali cattle. Ovaries of Bali cattle were collected by slicing, and only cytoplasmic oocytes with compact cumulus cells were used in this study. The oocytes were matured, and in vitro fertilization was performed using fertilization media with a final sperm concentration of 1.5 × 106 spermatozoa/mL. After 48 h, the embryo cleavage ability of the cultured oocytes was evaluated.

Results

There were significant differences in motility values between the NFS and PFS groups; however, there were no significant differences in the volume or sperm concentration. There was a significant difference in the LIN value between the groups but no significant differences in other CASA parameters. There were no significant differences in the cleavage rate and morula between the groups, but a positive correlation was observed between the cleavage rate and the morula and between the morula and ALH. A significant negative correlation was observed between the cleavage rate and STR and between the morula and STR; no significant differences were observed for other variables.

Conclusion

Despite variations in sperm characteristics, both normal and poor sperm motility demonstrated comparable in vitro embryonic development competence. These findings provide important insights into the fertility potential of Bali bulls, providing valuable information that can enhance selection strategies to improve the quality of livestock production.

The Influence of Abstinence Interval on Semen Quality and Its Effect on an Assisted Reproductive Technology (ART) Pregnancy: A Case Report

This case report focuses on a couple facing primary infertility, where the male partner exhibited asthenoteratozoospermia and high DNA fragmentation. The treatment approach involved three cycles of intracytoplasmic sperm injection (ICSI), an assisted reproductive technology (ART), to indicate and address the specific challenges posed by male factor infertility. The initial two attempts failed as DNA fragmentation was high, which was observed on days 4 and 3 of abstinence, respectively. In the third cycle, DNA fragmentation was low on day 2 of the abstinence period, resulting in the successful formation and cryopreservation of embryos. Subsequently, three months later, frozen embryo transfer (ET) was done. This was followed by a positive β-human chorionic gonadotropin (hCG) test after 14 days that confirmed biochemical pregnancy, and successful conception was determined by ultrasound detection of the visible sac with fetal pole. This report underscores the critical importance of treatment plans for individual patients, especially considering the impact of abstinence periods on sperm DNA fragmentation. The findings promote a personalized approach to assisted reproductive techniques, enhancing the success rate. It is recommended that further comprehensive studies be conducted to validate and anticipate these observations.

Effects of a short abstinence period on sperm quality in oligozoospermic men

OBJECTIVE

The aim of this study was to compare semen parameters and sperm DNA fragmentation (SDF) and explore the relationship between semen parameters and SDF between 2 and 7 days of abstinence and a short abstinence period (within 4 hours) in oligozoospermic infertile patients.

METHODS

Two semen samples were collected from infertile oligozoospermic men (n=34) after an abstinence period of 2 to 7 days and within 4 hours, respectively. Sperm parameters were compared between the two abstinence duration groups, including semen volume, sperm concentration, total sperm count, sperm motility, total motile sperm count (TMSC), morphology, and SDF.

RESULTS

The semen volume, concentration, and total sperm count were significantly decreased after 4 hours of abstinence than after 2 to 7 days of abstinence, with median differences of 1.2 mL (p<0.001), 2×106/mL (p=0.011), and 9.6×106/ejaculation (p<0.001), respectively. TMSC was significantly lower after a short abstinence, with a median difference of 4.24×106/ejaculate (p<0.001). However, there were no significance differences in the percentage of motility, the SDF, and the percentage of sperm with normal morphology. Interestingly, volume, concentration, total sperm count, sperm motility, and SDF, but not TMSC, exhibited significant linear correlations between the two abstinence groups in univariate regression analysis, except for TMSC.

CONCLUSION

In oligozoospermic men, the volume, concentration, and total sperm count were significantly lower after a short abstinence period, but without adverse effects on sperm motility and SDF.

Seasonal variations in gonadosomatic index and seminal quality of squirrel monkeys (Saimiri collinsi)

BACKGROUND

We hypothesized that seasonal variations in testicular biometry in Saimiri collinsi are influenced by body mass and that testicular enlargement is related to improved seminal quality. Therefore, the gonadosomatic index (GSI) can be a tool to determine reproductive seasons and the predictors of seminal quality.

METHODS

Body mass, testicular biometry, and semen samples were obtained from eight adult males monthly and evaluated.

RESULTS

In the non-fattening/non-reproductive season, the body mass and GSI decreased and increased, respectively, in the fattening. A positive correlation was only observed between the GSI and seminal volume. During fattening, high seminal volume and normal morphology were observed, but sperm concentrations were low.

CONCLUSION

The GSI cannot be used as a predictor of seminal quality, but selective pressure to improve seminal quality may increase the chances of fertilization at fattening. The GSI provides new information on seasonality and can be used to identify reproductive seasons in squirrel monkeys.

Maternal Exposure to Per- and Polyfluoroalkyl Substances (PFAS) and Male Reproductive Function in Young Adulthood: Combined Exposure to Seven PFAS

BACKGROUND

Concerns remain about the human reproductive toxicity of the widespread per- and polyfluoroalkyl substances (PFAS) during early stages of development.

OBJECTIVES

We examined associations between maternal plasma PFAS levels during early pregnancy and male offspring reproductive function in adulthood.

METHODS

The study included 864 young men (age range:18.9-21.2 y) from the Fetal Programming of Semen Quality (FEPOS) cohort established between 2017 and 2019. Plasma samples from their mothers, primarily from the first trimester, were retrieved from the Danish National Biobank and levels of 15 PFAS were measured. Seven PFAS had detectable levels above the limit of detection in >80% of the samples and were included in analyses. Semen quality, testicular volume, and levels of reproductive hormones and PFAS were assessed in the young men. We used weighted quantile sum (WQS) regression to estimate the associations between combined exposure to maternal PFAS and reproductive function, and negative binomial regression to estimate the associations of single substances, while adjusting for a range of a priori-defined fetal and postnatal risk factors.

RESULTS

By a 1-unit increase in the WQS index, combined maternal PFAS exposure was associated with lower sperm concentration (-8%; 95% CI: -16%, -1%), total sperm count (-10%; 95% CI: -17%, -2%), and a higher proportion of nonprogressive and immotile sperm (5%; 95% CI: 1%, 8%) in the young men. Different PFAS contributed to the associations with varying strengths; however, perfluoroheptanoic acid was identified as the main contributor in the analyses of all three outcomes despite the low concentration. We saw no clear association between exposure to maternal PFAS and testicular volume or reproductive hormones.

DISCUSSION

In a sample of young men from the general Danish population, we observed consistent inverse associations between exposure to maternal PFAS and semen quality. The study needs to be replicated in other populations, taking combined exposure, as well as emerging short-chain PFAS, into consideration. https://doi.org/10.1289/EHP10285.

The Effect of Male Sexual Abstinence Periods on the Clinical Outcomes of Fresh Embryo Transfer Cycles Following Assisted Reproductive Technology: A Meta-Analysis

A sexual abstinence period (SAP) lasting for 2–7 days is recommended before undertaking semen analyses. However, there is no consensus regarding the length of the SAP for couples using assisted reproductive technology (ART). Therefore, a meta-analysis was performed to compare the effect of short SAPs (less than 4 days) and long SAPs (4–7 days) on the clinical outcomes of fresh embryo transfer cycles after ART. A total of four studies were included in the meta-analysis. Although the fertilization rate in short SAP couples was higher than that in long SAP couples, a pooled analysis demonstrated that it was not statistically significant (p = .09). The implantation rate was, however, significantly higher in short SAP couples (p = .0001). The pooled analysis revealed that the pregnancy rate was significantly higher in short SAP couples than that in long SAP couples. The overall odds ratio (OR) for the pregnancy rate was 1.44 (p = .0006). No significant difference in miscarriage rates between the short and long SAP couples was found (p = .88). The meta-analysis indicates that a shorter abstinence period could result in higher implantation and pregnancy rates for patients undertaking ART treatments.

Male sperm storage impairs sperm quality in the zebrafish

Variation in sperm traits is widely documented both at inter- and intraspecific level. However, sperm traits vary also between ejaculates of the same male, due for example, to fluctuations in female availability. Variability in the opportunities to mate can indeed have important consequences for sperm traits, as it determines how often sperm are used, and thus the rate at which they are produced and how long they are stored before the mating. While being stored within males’ bodies, sperm are subjected to ageing due to oxidative stress. Sperm storage may significantly impair sperm quality, but evidence linking male sperm storage and variation in sperm traits is still scarce. Here, we tested the effect of the duration of sperm storage on within-male variation in sperm traits in the zebrafish, Danio rerio. We found that without mating opportunities, sperm number increased as storage duration increased, indicating that sperm continue to be produced and accumulate over time within males without being discharged in another way. Long sperm storage (12 days) was associated with an overall impairment in sperm quality, namely sperm motility, sperm longevity, and sperm DNA fragmentation, indicating that sperm aged, and their quality declined during storage. Our results confirm that male sperm storage may generate substantial variation in sperm phenotype, a source of variation which is usually neglected but that should be accounted for in experimental protocols aiming to assay sperm traits or maximise fertilization success.

The Effect of Ejaculatory Abstinence Interval on Sperm Parameters and Clinical Outcome of ART. A Systematic Review of the Literature

Since the publication of the first edition of the WHO (World Health Organization) Laboratory Manual for the examination of Human Semen in 1980, the reference values of sperm parameters have been updated on four occasions. Currently and globally, most of the laboratories analyzing semen samples use the latest, 5th edition of the manual that recommends ejaculatory abstinence from two to seven days before producing the sample for examination. While this standardized interval of time facilitates the interpretation of the results and research, no solid evidence exists to support the WHO-recommended abstinence time for a semen analysis in order to optimize clinical outcomes after assisted reproduction. Most of the studies refer to different clinical outcomes, different groups of patients and different editions of the WHO Laboratory Manual, including heterogeneous intervals of abstinence or sperm parameters. The aim of the current systematic review was to evaluate available evidence correlating ejaculatory abstinence time with clinical outcomes and sperm parameters analyzed according to the last edition of the World Health Organization Laboratory Manual reference values in different male populations. The results from the included studies indicate that WHO abstinence recommendations may need revision, given that a shorter ejaculatory abstinence interval appears to be associated with improved sperm parameters, such as sperm DNA fragmentation, progressive motility or morphology, while evidence suggests a potential increase in embryo euploidy rates and pregnancy outcomes.

Short Ejaculatory Abstinence in Normozoospermic Men is Associated with Higher Clinical Pregnancy Rates in Sub-fertile Couples Undergoing Intra-Cytoplasmic Sperm Injection in Assisted Reproductive Technology: A Retrospective Analysis of 1691 Cycles

BACKGROUND

The current WHO abstinence recommendations are ideal only for clinical diagnosis, as in recent years a negative correlation of abstinence duration with good embryo development and clinical pregnancy rate has been seen.

AIM

The aim of the study was to evaluate the impact of variation in abstinence period on fertilization, embryo development potential, pregnancy, and miscarriage rate in sub-fertile couples undergoing assisted reproductive technology (ART) treatment.

SETTING AND DESIGN

A prospective analysis was conducted at a tertiary (level 3) infertility care clinic.

MATERIALS AND METHODS

The study included analysis of 1691 cycles for the patient undergoing ART procedures between September 2017 and August 2019. The influence of ejaculatory abstinence (EA) was investigated based on variation in abstinence length with four groups: Group I - 1 day; Group II - 2-5 days; Group III - 6-7 days; and Group IV - EA length of ≥8 days.

STATISTICAL ANALYSIS

Analysis of variance and Chi-square test were used to calculate P value.

RESULTS

In our primary outcome, we have seen a strong positive correlation of abstinence duration with semen volume, total sperm count, total motile count, and difference between each group was significant. Secondary outcomes showed a significantly higher implantation rate, biochemical pregnancy rate was observed in Group I (1 day) per embryo transfer as compared to longer abstinence groups. This resulted in significantly higher clinical pregnancy rates in Group I 30.0% vs. 25.4% in comparison to longer abstinence groups.

CONCLUSIONS

Our study has shown duration of abstinence is negatively correlated with positive β-human chorionic gonadotropin rate, clinical pregnancy rate, and implantation rate. Lower miscarriage rate was also observed with shorter abstinence duration.

Optimal timing for repeat semen analysis during male infertility evaluation

Objective

To assess whether the 4-week time period between semen analyses during the workup of male infertility is optimal and whether two samples are needed.

Design

Retrospective study.

Setting

Tertiary hospital.

Patient(s)

Men whose semen samples were obtained within 90 days of each other, without known fertility intervention, treatment, and/or azoospermia.

Intervention(s)

Semen analysis.

Main Outcome Measure(s)

Correlation between semen parameters and agreement among consecutive semen analyses.

Result(s)

A total of 2,150 semen samples from 1,075 men were included in the analysis. The optimal correlation for volume occurred at weeks 2, 8, and 12 (r = 0.803, r = 0.802, and r = 0.821, respectively). For concentration, the correlation was maximized at weeks 1, 4, and 5 (r = 0.950, r = 0.841, and r = 0.795, respectively). Total sperm count correlated at weeks 1, 2, and 4 (r = 0.929, r = 0.727, and r = 0.808, respectively). Motility was maximally correlated at weeks 1, 10, and 13 (r = 0.711, r = 0.760, and r = 0.708, respectively). Morphology was optimally correlated at weeks 1, 2, and 9 (r = 0.935, r = 0.815, and r = 0.839, respectively). Semen volume was correlated in 55% of men, sperm concentration in 64% of men, sperm motility in 52% of men and sperm morphology 64% of men.

Conclusion(s)

Our data suggest that four weeks may not be the optimal time for repeat semen analysis and that one sample is insufficient to assess any abnormalities in the result of semen analysis. The optimal time between repeat semen analyses should be individualized depending on the results of the initial analysis and additional factors, suggesting the need for future large-scale studies to investigate this trend.

Current Insights and Latest Updates in Sperm Motility and Associated Applications in Assisted Reproduction

Spermatozoon is a motile cell with a special ability to travel through the woman’s reproductive tract and fertilize an oocyte. To reach and penetrate the oocyte, spermatozoa should possess progressive motility. Therefore, motility is an important parameter during both natural and assisted conception. The global trend of progressive reduction in the number and motility of healthy spermatozoa in the ejaculate is associated with increased risk of infertility. Therefore, developing approaches for maintaining or enhancing human sperm motility has been an important area of investigation. In this review we discuss the physiology of sperm, molecular pathways regulating sperm motility, risk factors affecting sperm motility, and the role of sperm motility in fertility outcomes. In addition, we discuss various pharmacological agents and biomolecules that can enhance sperm motility in vitro and in vivo conditions to improve assisted reproductive technology (ART) outcomes. This article opens dialogs to help toxicologists, clinicians, andrologists, and embryologists in understanding the mechanism of factors influencing sperm motility and various management strategies to improve treatment outcomes.

Correlation between detergent activity and anti-herpes simplex virus-2 activity of commercially available vaginal gels

OBJECTIVE

Herpes simplex virus-2 (HSV-2) infections are almost exclusively sexually transmitted. The presence of vaginal gels during sexual activity may have a significant positive or negative impact on viral transmission. Therefore we investigated three off-the-shelf vaginal lubricants and one pH restoring gel to evaluate their impact on HSV-2 replication.

RESULTS

HeLa cells were infected with untreated virions and virions incubated with the particular gels. The accumulation of viral genomes was monitored by quantitative PCR (qPCR) method at 24 h post infection. Two of the tested gels had no significant effect on HSV-2 replication at the maximum applied concentration, while two had a strong inhibitory effect (~ 98% reduction of replication). The replication inhibitory effect was observed at various multiplicity of infection (MOI 0.4-6.4) and the two inhibitory gels were also capable of inhibiting the HSV-2 induced cytopathic effect on HeLa cells. The surface tension decreasing activity-an indication of detergent activity-was strongly correlated with the anti-HSV-2 activity of the gels (R²: 0.88). Our results indicate that off-the-shelf vaginal gels have a markedly different anti-HSV-2 activity that may influence HSV-2 transmission.

Biomarkers for demographic research: sperm counts and other male infertility biomarkers

Some male infertility biomarkers are etiologically linked to idiopathic infertility in men, the direct cause of which often cannot be determined with conventional sperm count parameters. Open questions remain regarding the universal and generic infertility definitions that cover and combine the clinical, epidemiological, and demographic perspectives. The main effort in the application of these infertility biomarkers are accounted by more or less strict discrimination criteria. For male infertility, beyond classical sperm count assessments, the DNA fragmentation index (DFI) is an adequate biomarker. DFI strongly correlates with pregnancy rates and even strict discrimination criteria for infertility outcomes. Other common biomarkers are reactive oxygen species (ROS) and antisperm antibodies (ASAs), which can explain some biomedical infertility disorders within major constraints. More frequently applied in demographic research, telomere length component analysis is based on identifying the genetic impact of cellular longevity. Sperm telomere length is becoming established as a potential biomarker in infertility research. The aim of this review is to provide an overview of the current status and limitations to the application of novel biomarkers, including TEX101, for infertility research. The review also discusses potential options for the use of biomarkers in population-based studies.Abbreviations: ASAs: antisperm antibodies; DFI: DNA fragmentation index; DNA: deoxyribonucleic acid; ECM1: extracellular matrix protein 1; FSH: follicle stimulating hormone; HS: hypospermatogenesis: IVF: in vitro fertilization; LDHC: L-lactata dehydrogenase C chain; MA: maturation arrest; microTESE: microdissection testicular sperm extraction; NOA: nonobstructive azoospermia; NP: nonprogressive; OA: obstructive azoospermia; pH: potential Hyrogenii (pH-value); PR: progressive; PTGDS: prostaglandin D synthese; ROS: reactive oxygen species; SA: semen analysis; SCO: sertoli cell only; SCSA: sperm chromatin structure assay (SCSA); TL: telomere length; TESE: testicular sperm extraction; TEX101: a glycoprotein that belongs to Ly6/urokinase type plasminogen activator receptor-like protein (uPAR)(LU) superfamily, to be a germ-cell-specific molecular sperm extraction; TUNEL: terminal deoxnucleotidyl dispersion tranferase dUTP nick-end labeling; WHO: World Health Organization.

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.