Sperm DNA fragmentation is correlated with poor embryo development, lower implantation rate, and higher miscarriage rate in reproductive cycles of non-male factor infertility

Correlation of sperm DNA damage with blastocyst formation: systematic review and meta-analysis

Background

The routine semen analysis fails to detect sperm DNA damage which contributes to the majority of male factor infertility. Sperm DNA fragmentation test (DFI) measures the sperm DNA damage. Blastocyst formation is an important step in IVF ± ICSI. At present, the literature lacks any data that correlates DFI and blastocyst formation.

Main body of the abstract

We searched MEDLINE and other databases till 2020 for the studies that reported on sperm DNA damage and blastocyst formation in assisted reproductive technology (ART). The outcomes analyzed were (1) a comparison of blastulation rates in high DFI and low DFI groups. (2) Comparison of blastulation rates in high DFI and low DFI groups based on (a) different sperm DNA fragmentation assays (COMET, SCD, SCSA, TUNEL), (b) different types of ART (IVF/IVF + ICSI/ICSI). 10 studies were included in this review. A non-significant increase in the blastocyst formation was observed in high DFI group (OR = 0.70; 95% CI = 0.4 to 1.21; P = 0.20) and with SCD and TUNEL assays.

Short conclusion

Our study emphasizes on sperm DNA fragmentation (sperm DNA damage) as an important marker of blastocyst formation. The results of this meta-analysis suggest that the high sperm DNA fragmentation may not adversely affect the blastocyst formation.

Effects of common Gram-negative pathogens causing male genitourinary-tract infections on human sperm functions

Male genitourinary tract (MGT) bacterial infections are considered responsible for 15% of male infertility, but the mechanisms underlying decreased semen quality are poorly known. We evaluated in vitro the effect of strains of Gram-negative uropathogenic species (two E.coli strains, three K. pneumoniae strains, P. aeruginosa and E. cloacae) on motility, viability, mitochondrial oxidative status, DNA fragmentation and caspase activity of human spermatozoa. All strains, except P. aeruginosa, reduced significantly sperm motility, with variable effects. Sperm Immobilizing Factor (SIF) was largely responsible for deteriorating effects on sperm motility of E. coli strains since they were completely reverted by knockout of SIF coding recX gene. Sequence alignment for RecX showed the presence of high homologous sequences in K. pneumoniae and E. cloacae but not in P. aeruginosa. These results suggest that, in addition to E.coli, other common uropathogenic Gram-negative bacteria affect sperm motility through RecX products. In addition to sperm motility, the E. coli strain ATCC 35218 also affected sperm viability, and induced caspase activity, oxidative stress and DNA fragmentation suggesting an interspecies variability in the amount and/or type of the produced spermatotoxic factors. In general, our results highlight the need for a careful evaluation of semen infections in the diagnostic process of the infertile man.

Paternal age over 50 years decreases assisted reproductive technology (ART) success: A single UK center retrospective analysis

INTRODUCTION

To study whether paternal age exerts an effect, independent of maternal age, on the outcomes of fresh in vitro fertilization/ intracytoplasmic sperm injection (IVF/ICSI) cycles. Semen quality deteriorates with increasing paternal age; however, there is conflicting evidence for any impact paternal age may have on the outcome of IVF/ICSI. Several retrospective and prospective cohort studies have shown that paternal age increases the miscarriage rate and reduces the live birth rate. Some studies have shown no effect of paternal age on live birth rate or miscarriage rate. Studies involving donor oocytes have tended to show no independent effect of paternal age on assisted reproductive technology (ART) outcomes. The age at which paternal age may exert a significant deleterious effect on outcome is not known and there is no limit to paternal age in IVF/ICSI treatment.

MATERIAL AND METHODS

A single-center retrospective cohort study was carried out at the Centre for Reproductive and Genetic Health, London, UK. Included in the analysis were all couples with primary or secondary infertility undergoing IVF/ICSI cycles in which the male partner produced a fresh semen sample and the cycle proceeded to fresh embryo transfer. All cycles of IVF/ICSI that used donor oocytes-donor sperm, frozen sperm, cycles leading to embryo storage and cycles including preimplantation genetic testing (PGT-A/PGT-M)-were excluded from analysis. The primary outcome was live birth rate and secondary outcomes were clinical pregnancy rate and miscarriage rate. Multivariate logistic regression analysis with live birth as a dependent variable and maternal and paternal age class as independent variables was performed.

RESULTS

During the study period there were 4833 cycles, involving 4271 men, eligible for analysis; 1974/4833 (40.8%, 95% confiene intervals [CI] 39.5-42.2%) cycles resulted in a live birth. A significantly lower proportion of men over 51 years met World Health Organization semen analysis criteria (56/133, [42.1%, 95% CI 34.1-50.6]) compared with men under 51 years of age (2530/4138 [61.1%, 95% CI 60.0-62.6]) (p = 0.001). Both maternal and paternal age were retained in the multivariate model and for all maternal age subgroups the probability of live birth decreased with paternal age over 50 years (odds ratio [OR] 0.674, 95% CI 0.482-0.943) (p = 0.021). Paternal age over 50 years was not an independent predictor of miscarriage (OR 0.678, 95% CI 0.369-1.250) (p = 0.214).

CONCLUSIONS

Paternal age over 50 significantly affects the chance of achieving a live birth following ART. Paternal age does not independently affect the risk of miscarriage following ART. There should be a public health message for men not to delay fatherhood.

Influence of cleavage-stage embryo quality on the in-vitro fertilization outcome after single embryo transfer in fresh cycles

OBJECTIVE

Embryo quality is crucial for determining the outcome of embryo implantation. This study aimed to assess the impact of embryo quality on the outcome of in vitro fertilization/single-embryo transfer (IVF-SET).

MATERIALS AND METHODS

This retrospective study included 2531 fresh IVF-SET cycles, including 277 poor-quality and 2254 top-quality embryos. The clinical pregnancy rate, miscarriage rate, live birth, implantation rate, pregnancy outcome and complication were analyzed and compared. Risk factors associated with miscarriage rate and pregnancy complication were identified using logistics regression analysis.

RESULTS

Top-quality embryos resulted in higher clinical pregnancy rate (30.5% vs. 12.6%, P < 0.001) and live birth rate (23.9% vs. 9.7%, P < 0.001) compared with poor-quality embryos. Logistics regression analysis revealed that embryo quality was not correlated with miscarriage rate (95% CI 0.33-1.89) and pregnancy complications (95% CI 0.12-7.84). Maternal age and body mass index was a risk factor for miscarriage rate (95% CI 1.05-1.22) and pregnancy complication (95% CI 1.01-1.29), respectively.

CONCLUSION

Clinical miscarriage rate and pregnancy complication were embryo quality independent. Maternal age was the risk factor for miscarriage rate. Embryo quality did not affect miscarriage once a clinical pregnancy is achieved.

Correlation between sperm DNA fragmentation index and semen parameters in 418 men seen at a fertility center

Objective:

Methods:

Results:

Conclusions:

The paternal toolbox for embryo development and health

The sperm is essential for reconstitution of embryonic diploidy and highly specialized developmental functions. Immediately after gamete fusion, the sperm-borne PLC-zeta triggers activation, generating intracellular free Ca2+ oscillations. Mutations in the PLC-zeta encoding gene are associated with the absence of this factor in mature sperm and inability to achieve fertilization. Sperm play also a role in the greater game of the choreography of fertilization. In the human, the sperm centrioles are introduced into the oocyte environment with gamete fusion. They interact with the oocyte cytoskeletal apparatus to form a functional pair of centrosomes and ultimately regulate pronuclear juxtaposition in preparation for the first cleavage. As a consequence, the fidelity of chromosome segregation during the first cell divisions depends on the function of sperm centrioles. Sperm DNA integrity is essential for embryo development and health. Damaged DNA does not impact on the sperm fertilization ability following ICSI. However, detrimental effects emerge at pre- and post-implantation stages. Sperm-specific epigenetic factors also play an active role in the regulation of embryonic development, as shown by correlations between reduced embryo morphological quality and incorrect chromatin packaging during spermiogenesis or abnormal methylation of sperm CpG islands. This functional landscape demonstrates that the contribution of the sperm to development goes far beyond its well-established role in fertilization. Clinical studies confirm this view and indicate sperm function as a crucial aspect of research to increase the efficacy of assisted reproduction treatments.

Selection of high-quality sperm with thousands of parallel channels

Sperm selection is essential for successful fertilization and embryo development. Current clinical sperm selection methods are labor-intensive and lack the selectivity required to isolate high-quality sperm. Microfluidic sperm selection approaches have shown promise but present a trade-off between the quality and quantity of selected sperm - clinicians demand both. The structure of the female reproductive tract helps to isolate a sufficient quantity of high-quality sperm for fertilization with densely folded epithelium that provides a multitude of longitudinally oriented pathways that guide sperm toward the fertilization site. Here, a three-dimensionally structured sperm selection device is presented that levers this highly parallelized in vivo mechanism for in vitro sperm selection. The device is inserted in a test tube atop 1 mL of raw semen and provides 6500 channels that isolate ∼100 000 high-DNA-integrity sperm for assisted reproduction. In side-by-side clinical testing, the developed approach outperforms the best current clinical methods by improving the DNA integrity of the selected sperm subpopulation up to 95%. Also, the device streamlines clinical workflow, reducing the time required for sperm preparation 3-fold. This single-tube, single-step sperm preparation approach promises to improve both the economics and outcomes of assisted reproduction practices, especially in cases with significant male-factors.

Complete Chromatin Decondensation of Pig Sperm Is Required to Analyze Sperm DNA Breaks With the Comet Assay

Sperm quality is usually evaluated prior to artificial insemination in farm animals. In addition to conventional semen analysis, other biomarkers, such as mitochondrial activity, integrity and lipid disorder of plasma membrane, generation of reactive oxygen species (ROS) and sperm DNA integrity, have been found to be related to fertility rates in different species. While mounting evidence indicates that the Comet assay is a sensitive method for the detection of DNA breaks, complete sperm chromatin decondensation is required in order to properly analyze the presence of single- and double-strand DNA breaks. In this sense, a previous study showed that longer lysis treatment with proteinase K is needed to achieve complete chromatin decondensation. The current work sought to determine which specific lysis treatment leads to complete chromatin decondensation in pig sperm, as this is needed for the measurement of DNA damage in this species. With this purpose, incubation with a lysis solution containing proteinase K for 0, 30, and 180 min was added to the conventional protocol. The impact of the DNA damage induced by hydrogen peroxide (H₂O₂; 0.01 and 0.1%) and DNAse I (1U and 4U) was also evaluated. Complete chromatin decondensation was only achieved when a long additional lysis treatment (180 min) was included. Furthermore, olive tail moment (OTM) and percentage of tail DNA (TD) indicated that a higher amount of DNA breaks was detected when hydrogen peroxide and DNAse I treatments were applied (P < 0.05). The comparison of treated and control sperm allowed defining the thresholds for OTM; these thresholds revealed that the percentage of sperm with fragmented DNA determined by the alkaline Comet does not depend on chromatin decondensation (P > 0.05). In conclusion, complete chromatin decondensation prior to alkaline and neutral Comet assays is needed to analyze DNA breaks in pig sperm.

Predictive Significance of Sperm DNA Fragmentation Testing in Early Pregnancy Loss in Infertile Couples Undergoing Intracytoplasmic Sperm Injection

Objective

This study aimed to determine the role of sperm DNA fragmentation as a marker that could predict early pregnancy loss (EPL), either independently or in combination with another marker or markers, after intracytoplasmic sperm injection (ICSI) cycles.

Methods

This prospective descriptive cohort study retrieved data from 162 couples who underwent their first ICSI cycles at the Center for Reproductive Endocrinology and Infertility of Hue University Hospital in Vietnam from May 2018 to December 2019. General characteristics, semen parameters, sperm DNA fragmentation index (DFI), fertilization, embryo development, pregnancy rates, and EPL were assessed. The receiver-operating characteristic (ROC) method was performed to identify the threshold of DFI in EPL. Multivariate analysis was used to demonstrate the relationship between the sperm DNA fragmentation level and EPL.

Results

Of 162 ICSI cycles, 23 (14.2%) involved EPL. There was no significant difference between the sperm DNA fragmentation rate and the overall rate of pregnancy loss, although the negative pregnancy outcome group had a median DFI that was higher than that of the positive pregnancy outcome group (20% vs 17.8%). The ROC analysis indicated that a sperm DNA fragmentation rate of 16.6% was the priority cut-off that could be used to distinguish EPL with a sensitivity of 73.9% (95% confidence interval [CI], 67.15-80.67) and specificity of 47.48% (95% CI, 39.79-55.17). The multivariate analysis confirmed that in female factors such as age, body mass index (BMI), and sperm DNA fragmentation level affected the EPL rate. However, a combination of the sperm DNA fragmentation level and female age or female BMI could not sufficiently predict EPL.

Conclusion

EPL can be affected by multiple factors including sperm DNA fragmentation; however, there is no sufficient evidence indicating that sperm DNA fragmentation, both as a single marker and combined with other markers, is a good predictor of EPL.

Mitochondrial Dynamics Markers and Related Signaling Molecules Are Important Regulators of Spermatozoa Number and Functionality

Here, we study possible mechanisms of (in/sub)fertility related to the acute or repeated psychological stresses (the most common stresses in human society) by following the transcriptional profile of 22 mitochondrial dynamics/function markers and 22 signaling molecules regulating both mitochondrial dynamics and spermatozoa number/functionality. An in vivo study mimicking acute (once for 3 h) and repeated (3 h for 10 consecutive days) psychophysical stress was performed on adult rats. The analysis of hormones, the number/functionality of spermatozoa, and 44 transcriptional markers were performed on individual samples from up to 12 animals per group. Results showed that both types of stress reduced spermatozoa functionality (acute by 4.4-fold, repeated by 3.3-fold) and ATP production (acute by 2.3-fold, repeated by 14.5-fold), while only repeated stress reduces the number of spermatozoa (1.9-fold). Stress significantly disturbed transcription of 34-out-of-44 markers (77%). Mitochondrial dynamics and functionality markers: 18-out-of-22 =>82% (mitochondrial-biogenesis-markers –>6-out-of-8 =>75%; mitochondrial-fusion-markers –>3-out-of-3 =>100%; mitochondrial-fission-markers –>1-out-of-2 =>50%; mitochondrial-autophagy-markers –>3-out-of-3 =>100%; mitochondrial-functionality-markers –>5-out-of-6 =>83%). Markers of signaling pathways regulating both mitochondrial dynamics/functionality and spermatozoa number/functionality important for male (in/sub)fertility –>16-out-of-22 =>73% (cAMP-signaling-markers –>8-out-of-12 =>67%; MAPK-signaling-markers –>8-out-of-10 =>80%). Accordingly, stress-triggered changes of transcriptional profile of mitochondrial dynamics/functionality markers as well as signaling molecules regulating both mitochondrial dynamics and spermatozoa number and functionality represent adaptive mechanisms.

Sperm DNA fragmentation measured by sperm chromatin dispersion impacts morphokinetic parameters, fertilization rate and blastocyst quality in ICSI treatments

To determine the effects of sperm DNA fragmentation (SDF) on embryo morphokinetic parameters, cleavage patterns and embryo quality, this retrospective study analyzed 151 intracytoplasmic sperm injection (ICSI) cycles (1152 embryos collected) between November 2016 and June 2019. SDF was assessed using sperm chromatin dispersion. The cycles were divided into two groups based on the SDF rate: SDF < 15% (n = 114) and SDF ≥ 15% (n = 37). The embryo morphokinetic parameters, cleavage patterns, and embryo quality were compared between the two groups. The morphokinetic parameters tPNf, t2, t3, t4, t5, t6, and t8 were achieved significantly earlier in the SDF < 15% group compared with in the SDF ≥ 15% group. The fertilization and 2PN rates seemed to be significantly higher in the SDF < 15% group compared with in the SDF ≥ 15% group, while the abnormal cleavage rates were similar. However, a significantly higher rate of chaotic cleavage (CC) was observed in the SDF ≥ 15% group. The D3 high-quality embryo and available embryo rates were similar between the two groups. The blastocyst formation, high-quality blastocyst, and available blastocyst rates in the SDF < 15% group were significantly higher than those in the SDF ≥ 15% group. With an increase in SDF level, the chemical pregnancy, clinical pregnancy and implantation rates tended to decrease, while the miscarriage rate increased. This study demonstrated that SDF ≥ 15% reduces the fertilization rate of ICSI cycles and affects certain morphokinetic parameters. A higher SDF level can also induce a higher rate of CC, with subsequent decreases in the blastocyst formation rate and blastocyst quality.

High mRNA expression of GABA receptors in human sperm with oligoasthenoteratozoospermia and teratozoospermia and its association with sperm parameters and intracytoplasmic sperm injection outcomes

Objective

This study investigated the mRNA expression of gamma-aminobutyric acid (GABA) receptors in the sperm of oligoasthenoteratozoospermic (OAT) and teratozoospermic (TER) men compared to normozoospermic (NOR) men, as well as the relationships between GABA receptor expression and sperm parameters, fertilization rate, and embryo quality.

Methods

The mRNA expression of GABA A-α1 and GABA B-R2 receptors in sperm was examined using reverse transcription–polymerase chain reaction in three groups of patients: NOR (n=32), OAT (n=22), and TER (n=45). The fertilization rate and embryo quality were assessed in 35 patients undergoing intracytoplasmic sperm injection (ICSI; 10 NOR, 10 OAT, and 15 TER men).

Results

OAT men had significantly higher mRNA expression of GABA A-α1 and GABA B-R2 receptors in sperm than NOR men; however, the difference between TER and NOR men was not significant. High levels of these receptors were significantly correlated with low sperm concentration, motility, and morphology, as well as the rate of good-quality embryos (GQEs) at the cleavage stage after ICSI. Patients whose female partners had a >50% GQE rate at the cleavage stage had significantly lower levels of GABA A-α1 receptor expression than those whose partners had a ≤50% GQE rate.

Conclusion

Our findings indicate that mRNA levels of GABA receptors in human sperm are correlated with poor sperm quality and associated with embryo development after ICSI treatment. The GABA A-α1 receptor in sperm has a stronger relationship with embryo quality at the cleavage stage than the GABA B-R2 receptor.

Clinical implications of sperm DNA damage in IVF and ICSI: updated systematic review and meta-analysis

The clinical effect of sperm DNA damage in assisted reproduction has been a controversial topic during recent decades, leading to a variety of clinical practice recommendations. While the latest European Society of Human Reproduction and Embryology (ESHRE) position report concluded that DNA damage negatively affects assisted reproduction outcomes, the Practice Committee of the American Society for Reproductive Medicine (ASRM) does not recommend the routine testing of DNA damage for in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Herein, our aim was to perform a systematic review and meta-analysis of studies investigating whether sperm DNA damage affects clinical outcomes in IVF and ICSI, in order to contribute objectively to a consistent clinical recommendation. A comprehensive systematic search was conducted according to PRISMA guidelines from the earliest available online indexing year until March 2020, using the MEDLINE-PubMed and EMBASE databases. We included studies analysing IVF and/or ICSI treatments performed in infertile couples in which sperm DNA damage was well defined and assessed. Studies also had to include information about pregnancy, implantation or live birth rates as primary outcomes. The NHLBI-NIH quality assessment tool was used to assess the quality of each study. Meta-analyses were conducted using the Mantel-Haenszel method with random-effects models to evaluate the Risk Ratio (RR) between high-DNA-damage and control groups, taking into account the 95% confidence intervals. Heterogeneity among studies was evaluated using the I² statistic. We also conducted sensitivity analyses and post-hoc subgroup analyses according to different DNA fragmentation assessment techniques. We identified 78 articles that met our inclusion and quality criteria and were included in the qualitative analysis, representing a total of 25639 IVF/ICSI cycles. Of these, 32 articles had sufficient data to be included in the meta-analysis, comprising 12380 IVF/ICSI cycles. Meta-analysis revealed that, considering IVF and ICSI results together, implantation rate (RR = 0.74; 95% CI = 0.61-0.91; I²  = 69) and pregnancy rate (RR = 0.83; 0.73-0.94; I²  = 58) are negatively influenced by sperm DNA damage, although after adjustment for publication bias the relationship for pregnancy rate was no longer significant. The results showed a non-significant but detrimental tendency (RR = 0.78; 0.58-1.06; I²  = 72) on live birth rate. Meta-analysis also showed that IVF outcomes are negatively influenced by sperm DNA damage, with a statistically significant impact on implantation (RR = 0.68; 0.52-0.89; I²  = 50) and pregnancy rates (RR = 0.72; 0.55-0.95; I²  = 72), although the latter was no longer significant after correction for publication bias. While it did not quite meet our threshold for significance, a negative trend was also observed for live birth rate (RR = 0.48; 0.22-1.02; I²  = 79). In the case of ICSI, non-significant trends were observed for implantation (RR = 0.79; 0.60-1.04; I²  = 72) or pregnancy rates (RR = 0.89; 0.78-1.02; I²  = 44), and live birth rate (RR = 0.92; 0.67-1.27; I²  = 70). The current review provides the largest evidence to date supporting a negative association between sperm DNA damage and conventional IVF treatments, significantly reducing implantation and pregnancy rates. The routine use of sperm DNA testing is therefore justified, since it may help improve the outcomes of IVF treatments and/or allow a given couple to be advised on the most suitable treatment. Further well-designed controlled studies on a larger number of patients are required to allow us to reach more precise conclusions, especially in the case of ICSI treatments.

Sperm DNA fragmentation on the day of fertilisation is not associated with assisted reproductive technique outcome independently of gamete quality

The evaluation of sperm DNA fragmentation has been postulated as a predictive molecular parameter of the semen fertilising potential, as well as the ability to give rise to a healthy embryo and an ongoing pregnancy. However, there are controversial results due to oocyte quality, the use of different measurement techniques and interpretation criteria. Our objective is to investigate if sperm DNA fragmentation on the day of fertilisation influences in vitro fertilisation (IVF) outcome in a prospective double-blind study. Three groups of patients were defined: (i) 68 couples undergoing intracytoplasmic sperm injection (ICSI) due to severe male factor with normal ovarian response (NOR); (ii) 113 couples undergoing conventional in vitro fertilisation (IVF) in our oocyte donation programme due to ovarian failure; and (iii) 150 low ovarian response (LOR) patients undergoing ICSI or IVF. TUNEL assay was performed from an aliquot of each capacitated semen sample to detect DNA fragmentation. There was no relationship between blood serum β-hCG positive test, clinical pregnancy and first trimester miscarriage with DFI levels in NOR (p = 0.41, p = 0.36, p = 0.40), recipient (p = 0.49, p = 0.99 and p = 0.38) and LOR (p = 0.52, p = 0.20, p = 0.64) groups of patients, respectively. Therefore, ART outcomes are not affected by sperm DNA fragmentation independently of gamete quality.

An Update on the Relationship of SARS-CoV-2 and Male Reproduction

Since the outbreak of the COVID-19, up to now, infection cases have been continuously rising to over 200 million around the world. Male bias in morbidity and mortality has emerged in the COVID-19 pandemic. The infection of SARS-CoV-2 has been reported to cause the impairment of multiple organs that highly express the viral receptor angiotensin-converting enzyme 2 (ACE2), including lung, kidney, and testis. Adverse effects on the male reproductive system, such as infertility and sexual dysfunction, have been associated with COVID-19. This causes a rising concern among couples intending to have a conception or who need assisted reproduction. To date, a body of studies explored the impact of SARS-CoV-2 on male reproduction from different aspects. This review aims to provide a panoramic view to understand the effect of the virus on male reproduction and a new perspective of further research for reproductive clinicians and scientists.

Paternal Subclinical Hypothyroidism Affects the Clinical Outcomes of In Vitro Fertilization/Intracytoplasmic Sperm Injection

Background: Maternal subclinical hypothyroidism (SCH) is a risk factor for adverse pregnancy outcomes. However, it is still unclear whether SCH affects male fertility. The aim of this study was to determine the association between paternal SCH and clinical outcomes after in vitro fertilization/intracytoplasmic sperm injection (IVF/ICSI). Methods: This retrospective study included 2511 couples with paternal euthyroidism (n = 2282) or SCH (n = 229) who visited our clinic for infertility treatment between April 1, 2017, and September 30, 2019. The primary outcomes were the fertilization rate and clinical pregnancy rate; the secondary outcomes were the good-quality embryo rate, blastocyst formation rate, implantation rate, and early miscarriage rate. These outcomes were compared between the euthyroid and the SCH groups after adjusting for various potential confounders. Results: The mean paternal ages in the euthyroid and SCH groups were 34.5 and 36.0 years, respectively (p = 0.002). Semen parameters and sperm DNA fragmentation index were similar between the two groups (all p > 0.05). The adjusted fertilization (0.69 vs. 0.71, p = 0.30), good-quality embryo (0.49 vs. 0.52, p = 0.31), blastocyst formation (0.51 vs. 0.53, p = 0.57), and early miscarriage (0.11 vs. 0.10, p = 0.81) rates were also similar between the two groups. There was a significantly decreased adjusted clinical pregnancy rate [confidence interval, CI] and implantation rate [CI] in the paternal SCH group compared with the euthyroid group (0.32 [0.26-0.40] vs. 0.42 [0.40-0.45], p = 0.009 for the clinical pregnancy rate; 0.24 [0.19-0.29] vs. 0.29 [0.27-0.31], p = 0.037 for the implantation rate). Stratified analysis indicated that these differences were only significant in men aged ≥35 years (p = 0.009 and 0.022, respectively) and not in men <35 years (p = 0.39 and 0.45, respectively). Conclusions: Paternal SCH was associated with worse clinical outcomes after IVF/ICSI, whereas this detrimental impact was only present in males ≥35 years old. Prospective studies and basic research are warranted to confirm these results and to clarify the mechanisms underlying these associations, respectively.

Decreased DNA Repair Ability: A Mechanism for Low Early Embryonic Development Potential of Oocytes From Overweight Patients After Fertilization in IVF Cycles

BACKGROUND

Whether female BMI impacts the DNA repair ability in the oocytes after fertilization has not been investigated. The aim of this study is to assess the early embryo quality and reproductive outcomes of oocytes from overweight women when fertilized with sperm with varying degrees of DNA fragmentation.

METHODS

A total number of 1,612 patients undergoing fresh autologous in vitro fertilization (IVF) cycles was included. These patients were divided into two groups according to maternal body mass index (BMI): normal weight group (18.5-24.9 kg/m²; n=1187; 73.64%) and overweight group (≥25 kg/m²; n=425; 26.36%). Each group was then subdivided into two groups by sperm DNA fragmentation index (DFI): low fragmentation group (<20% DFI, LF) and high fragmentation group (≥20% DFI, HF). Laboratory and clinical outcomes were compared between subgroups.

RESULTS

For the normal-weight group, there was no statistical significance in embryo quality and reproductive outcomes between the LF and HF groups. But in the overweight group, significantly lower fertilization rate (LF: 64%; HF: 59%; p=0.011), blastocyst development rate (LF: 57%; HF: 44%; p=0.001), as well as high-quality blastocyst rate (LF: 32%; HF: 22%; p=0.034) were found in the HF group, despite the similar pregnancy rates (LF: 56%; HF: 60%; p=0.630).

CONCLUSIONS

Decreased DNA repair activity in oocytes may be a possible mechanism for the low early development potential of embryos from overweight patients in in vitro fertilization cycles.

Use of a male antioxidant nutraceutical is associated with superior live birth rates during IVF treatment

Oxidative stress is prevalent among infertile men and is a significant cause of sperm DNA damage. Since sperm DNA damage may reduce embryo quality and increase miscarriage rates, it is possible that untreated sperm oxidative stress may impair in vitro fertilization (IVF) live birth rates. Given that the antioxidant Menevit is reported to reduce sperm DNA damage, it was hypothesized that men's consumption of this supplement may alter IVF outcomes. Therefore, a retrospective cohort study was conducted analyzing outcomes for couples undergoing their first fresh embryo transfer. Men were classified as controls if they were taking no supplements, health conscious controls if taking “general health” supplements, or Menevit users. Men with karyotype abnormalities, or cycles using donated, frozen and surgically extracted sperm were excluded. Among the final study cohort of 657 men, live birth rates were significantly higher in Menevit users than controls (multivariate adjusted odds ratio [OR]: 1.57, 95% confidence interval [CI]: 1.01–2.45, P = 0.046), but not between controls taking no supplements and those using general health supplements, thereby suggesting that potential health conscious behavior in supplement users is unlikely responsible for the superior outcomes in Menevit users. Interestingly, in a post hoc sensitivity analysis, live birth rates among Menevit users were statistically superior to controls for lean men (OR: 2.73, 95% CI: 1.18–6.28; P = 0.019), not their overweight/obese counterparts (OR: 1.29, 95% CI: 0.75–2.22, P = 0.37). The results of this large cohort study therefore support a positive association between men's use of the Menevit antioxidant during IVF treatment and live birth rates, especially in lean individuals.

Association of XRCC1 and ERCC2 promoters' methylation with chromatin condensation and sperm DNA fragmentation in idiopathic oligoasthenoteratozoospermic men

The aim of the study was to investigate whether the promoter methylation of XRCC1 and ERCC2 genes is associated with sperm DNA fragmentation and chromatin condensation in idiopathic oligoasthenoteratozoospermic men. This study involved 77 infertile men with idiopathic oligoasthenoteratozoospermia and 51 normozoospermic controls. The methylight method, TUNEL assay and aniline blue staining were used for the evaluation of XRCC1 and ERCC2 genes' methylation, SDF and sperm chromatin condensation, respectively. SDF (p = .004) and XRCC1 methylation (p = .0056) were found to be significantly higher in men with idiopathic OAT than in the controls, while mature spermatozoa frequency was higher in controls as compared to infertile men (p < .0001). No significant association was found between SDF and methylation of XRCC1 and ERCC2 genes (p = .9277 and p = .8257, respectively). However, compared to the cut-off point obtained by receiver operating characteristic analysis, a significant association was found between SDF and XRCC1 methylation, positive and negative methylation groups, generated according to the cut-off value for XRCC1. XRCC1 methylation was found to have a significant effect on chromatin condensation (p = .0017). No significant difference was detected among ERCC2 methylation, male infertility and SDF. In conclusion, XRCC1 methylation may have a role in sperm chromatin condensation and idiopathic OAT.

Reduced spermatozoa functionality during stress is the consequence of adrenergic-mediated disturbance of mitochondrial dynamics markers

Here we investigate the stress-signaling responsible for the effects of acute/repeated psychological stresses (the most common stresses in human society) on spermatozoa number and functionality, as well as the transcriptional profile of mitochondrial dynamics markers by using the in vivo and ex vivo approaches. Acute and repeated stress inhibit spermatozoa functionality (acute -> 3.2-fold, repeated -> 2.5-fold), while only repeated stress reduces the spermatozoa number (1.7-fold). Stress hormones mimic these effects and decrease the spermatozoa functionality (adrenaline: 10 µM -> 2.4-fold, 100 µM - > 2.8-fold; hydrocortisone: 50 pM -> 2.7-fold, 500 pM -> 8.5-fold). They also significantly disturb the transcriptional profile of all main mitochondrial dynamics markers in spermatozoa. Ex vivo manipulation of stress signaling in spermatozoa reveals that most of these effects are mediated through ɑ1-and/or-β-adrenergic receptors. The transcription of these receptors and their kinases in the same samples is under the significant influence of adrenergic signaling. Our results are the first to show the importance of mitochondrial dynamics markers in spermatozoa since the transcriptional profiles of sixteen-out-of-ninteen are disturbed by manipulation of stress-hormones-signaling. This is a completely new molecular approach to assess spermatozoa functionality and it is important for a better understanding of the correlations between stress, environmental-life-style and other factors, and male (in)fertility.

Does sperm DNA fragmentation have negative impact on embryo morphology and morphokinetics in IVF programme?

Evaluation of sperm integrity may predict the in vitro fertilisation (IVF) outcomes. The aim was to evaluate the relationship between the sperm DNA fragmentation (sDNAf) with embryo morphology and morphokinetic using time-laps monitoring (TLM) and to select the best time points for normalisation in IVF setting. After evaluating the fertilisation and pronuclei (Z) scoring, 328 normally fertilised oocytes were assessed to time of pronuclei fading, time of 2 to 8 discrete cells (t2-t8) and abnormal cleavage patterns, such as multinucleation, direct cleavage, reverse cleavage and fragmentation. Sperm chromatin dispersion (SCD) assay was used for assessment of prepared sperm chromatin status. SCD was categorised into 4 groups of <6.5, 6.5-10.7, 10.7-20.1 and >20.1. The finding showed significant differences in t6 (p = .012), t7 (p = .045), t8 (p = .013) and s1 (p = .001) between 4 SCD groups. When morphokinetic variables were normalised to tPNf, this difference was observed in t2 (p = .003) and t6 (p = .017). Subsequently, the percentage of top quality embryos and Z₁ scoring were dependent to the sDNAf rate. In conclusion, tPNf was the best reference time point in IVF cycles. Also, we found high sDNAf rate had no negative impact on embryo morphology and morphokinetics in conventional IVF.

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.

Impact of body mass index and metabolic syndrome on sperm DNA fragmentation in males from infertile couples: A cross-sectional study from Vietnam

Objectives

This study investigated the relationship between body mass index (BMI) and metabolic syndrome on sperm DNA fragmentation (SDF) in males from infertile couples.

Methods

This cross-sectional study was performed from September 2018 to September 2019 at the Hue Center for Reproductive Endocrinology and Infertility (HUECREI), Vietnam. The study included men from couples with at least one year of infertility, who were subjected to semen analysis and SDF assay (Halosperm). We also performed a 2-h oral glucose tolerance test and measured lipidemia. Metabolic syndrome (MetS) was defined based on the NHLBI/AHA-ATP III guidelines.

Results

The mean age of the patients was 35.26 ± 5.87 years and 53.8% of them had a BMI ≥23.0 kg/m². The DNA fragmentation index was significantly associated with overweight (p = 0.024). Men without MetS had a higher rate of big halos and a lower rate of small halos, no halos, and degraded semen compared to that in men with MetS, but the differences were not significant (p > 0.05). By performing multivariable analysis, we found that the SDF value was significantly different among the two groups with either overweight or normal weight.

Conclusion

In males from infertile couples with a relatively young mean age, BMI can be an independent indicator for SDF. MetS thus has a significant role in the development of sperm DNA fragmentation, at least in overweight individuals; it should thus be assessed under the scope of BMI, for better/earlier detection of increased SDF.

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Sperm DNA fragmentation recently appears to be a good marker for male reproductive potential.

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BMI can be an independent indicator for increasing SDF.

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MetS has a significant role in the development of SDF, at least in overweight individuals.

Comparative analysis of tests used to assess sperm chromatin integrity and DNA fragmentation

Male infertility has a complex etiology, and many times, the cause is unknown. While routine semen analysis provides an overview of basic semen parameters, such as sperm concentration, motility, viability and morphology, a significant overlap of these parameters has been reported in fertile and infertile men. Moreover, conventional semen parameters do not reveal the cellular or molecular mechanisms of sperm dysfunctions leading to infertility. Therefore, sperm functional parameters, including sperm chromatin integrity, are evaluated to provide information on subtle sperm defects that are not routinely identified. Incomplete or defective sperm chromatin condensation increases the susceptibility of the sperm DNA to oxidative damage or other factors. To evaluate sperm chromatin integrity, different methods with varying degrees of diagnostic and prognostic capabilities are available. Among these assays, SCSA, TUNEL and SCD assays are most commonly used. While these assays rather evaluate the DNA directly for damages, the aniline blue and chromomycin A3 stains test for the quality of chromatin condensation. Thus, this review discusses and compares different methods used to evaluate sperm chromatin integrity and condensation, and their inclusion in the routine evaluation of the male infertility.

Varicocele Repair Prior to Assisted Reproductive Technology: Patient Selection and Special Considerations

Clinical varicoceles are one of the most commonly identified physical exam abnormalities in men presenting with infertility. Clinical varicoceles can cause impaired spermatogenesis and surgical correction can improve semen parameters in select men. Increasingly, andrologists are performing varicocele repairs prior to intrauterine insemination (IUI), in vitro fertilization (IVF), and intracytoplasmic sperm injection (ICSI) to boost male fertility potential. In this review, we evaluated the available literature 1) to determine if varicocelectomy prior to IUI or assisted reproductive technologies proved to improve sperm production or pregnancy outcomes; and 2) to identify who may be the ideal candidate for pre-IUI/ART varicocelectomy. Overall, few studies have explored this topic and little can be concluded about the impact of varicocelectomy prior to IUI. The evidence, however, does support that correcting a clinical varicocele can increase pregnancy outcomes in couples who plan to pursue IVF or ICSI. When selecting patients for varicocelectomy prior to IUI or ART, clinicians should evaluate female age as improvement in semen parameters can take 6 months after varicocelectomy and this duration of time may be deleterious in cases of advanced maternal age when each cycle becomes increasingly important. Overall, the currently limited literature regarding clinical varicoceles correction demonstrates that pregnancy rates can be increased when comparing patients who have undergone varicocelectomy prior to ART with those who had clinical varicocele but did not undergo surgery.

Cutting-Edge Evaluation of Male Infertility

A male factor is a contributor in 50% of cases of infertility. Although assisted reproductive techniques can often bypass the need to improve semen parameters, the evaluation of the infertile man remains critical. Current methods for evaluating the infertile man are discussed, beginning with the basic workup that all suspected infertile men should undergo, followed by subsequent evaluation steps. Although the fundamental components of the evaluation have remained consistent, several new tools are available to assist in identifying the underlying etiology. As our understanding of male fertility expands, the technologies available to diagnose and ultimately treat it continue to evolve.

DNA Fragmentation in Viable and Non-Viable Spermatozoa Discriminates Fertile and Subfertile Subjects with Similar Accuracy

Sperm DNA fragmentation (sDF) negatively affects reproduction and is traditionally detected in total sperm population including viable and non-viable spermatozoa. Here, we aimed at exploring the ability of DNA fragmentation to discriminate fertile and subfertile men when detected in viable (viable sDF), non-viable (non-viable sDF), and total spermatozoa (total sDF). We revealed sDF in 91 male partners of infertile couples and 71 fertile men (max 1 year from natural conception) with LiveTUNEL coupled to flow cytometry, able to reveal simultaneously DNA fragmentation and cell viability. We found that the three sDF parameters discriminated fertile and subfertile men with similar accuracy and independently from age and basal semen parameters: AUCs (area under the curves) (95% CI) were: 0.696 (0.615–0.776), p < 0.001 for total sDF; 0.718 (0.640–0.797), p < 0.001 for viable sDF; 0.760 (0.685–0.835), p < 0.001 for non-viable sDF. We also found that total and non-viable but not viable sDF significantly correlated to age and semen quality. In conclusion, the three sDF parameters similarly discriminated fertile and subfertile men. Viable spermatozoa with DNA fragmentation are likely cells able to fertilize the oocyte but failing to properly support subsequent embryo development. Non-viable sDF could be a sign of a subtler damage extended beyond the non-viable cells.

Increasing associations between defects in phospholipase C zeta and conditions of male infertility: not just ICSI failure?

PURPOSE

Oocyte activation is a fundamental event at mammalian fertilization. In mammals, this process is initiated by a series of characteristic calcium (Ca²⁺) oscillations, induced by a sperm-specific phospholipase C (PLC) termed PLCzeta (PLCζ). Dysfunction/reduction/deletion of PLCζ is associated with forms of male infertility where the sperm is unable to initiate Ca²⁺ oscillations and oocyte activation, specifically in cases of fertilization failure. This review article aims to systematically summarize recent advancements and controversies in the field to update expanding clinical associations between PLCζ and various male factor conditions. This article also discusses how such associations may potentially underlie defective embryogenesis and recurrent implantation failure following fertility treatments, alongside potential diagnostic and therapeutic PLCζ approaches, aiming to direct future research efforts to utilize such knowledge clinically.

METHODS

An extensive literature search was performed using literature databases (PubMed/MEDLINE/Web of Knowledge) focusing on phospholipase C zeta (PLCzeta; PLCζ), oocyte activation, and calcium oscillations, as well as specific male factor conditions.

RESULTS AND DISCUSSION

Defective PLCζ or PLCζ-induced Ca²⁺ release can be linked to multiple forms of male infertility including abnormal sperm parameters and morphology, sperm DNA fragmentation and oxidation, and abnormal embryogenesis/pregnancies. Such sperm exhibit absent/reduced levels, and abnormal localization patterns of PLCζ within the sperm head.

CONCLUSIONS

Defective PLCζ and abnormal patterns of Ca²⁺ release are increasingly suspected a significant causative factor underlying abnormalities or insufficiencies in Ca²⁺ oscillation-driven early embryogenic events. Such cases could potentially strongly benefit from relevant therapeutic and diagnostic applications of PLCζ, or even alternative mechanisms, following further focused research efforts.

Differential microRNAs expression in seminal plasma of normospermic patients with different sperm DNA fragmentation indexes

Sperm DNA fragmentation index (SDF), as an important supplement to routine semen parameters, has been proposed to discriminate between fertile and infertile men, and predicts the outcomes of natural conception and in vitro fertilization. Unfortunately there are uncertainty and contradictory evidences regarding the importance of SDF. An important reason is the fact that significant and fundamental research about SDF is rare. This study was designed to characterize the microRNA (miRNA) expression profile in seminal plasma of normospermic patients with different SDF and their implications in human fertility. Using next-generation sequencing (NGS), a total of 897 human miRNAs were detected from 10 seminal plasma samples, out of which 431 differentially expressed miRNAs in 5 pairs of seminal plasma samples (each pair of seminal plasma samples obtained from the same male), with 14 miRNAs were identified in all the pairs. According to the fold change and expression level, 7 miRNAs including miR-374b-5p, miR-429, hsa-miR-26b-5p, miR-21-5p, miR-4257, miR-135b-5p and miR-134-5p were selected for further excavation. MiR-374b-5p and miR-26b-5p were significantly different in 3 sets of individual seminal plasma samples with different SDF from total 90 infertile patients (30 patients each set). Our results demonstrate that the profile of miR-374b and miR-26b with significantly decreased expression could be used as a first indication of increased SDF. And miR-374b and miR-26b could serve as adjunct biomarkers for the diagnosis of idiopathic infertile males.

Semen Quality is Associated with Sperm Aneuploidy and DNA Fragmentation in the United Arab Emirates Population

Background: Sperm chromosome aneuploidy and the extent of sperm DNA fragmentation (SDF) are contributing factors to male infertility. Their extent can be measured using platforms such as sperm chromatin dispersion (SCD) and sperm fluorescence in situ hybridization (sFISH). Additional studies, however, are needed to understand the clinical applicability of these in vitro tests based on statistically validated thresholds. Aim: The primary objective of this study was to report the incidence of SDF and chromosomal aneuploidy with respect to sperm quality in the United Arab Emirates (UAE) population. In addition, we wished to establish clinically useful SDF and aneuploidy cutoff values. Materials and Methods: A total of 302 subjects were enrolled in this study. The control group consisted of n = 100 (33.11%) reproductively-proven fertile men, and the case group consisted of n = 202 (66.89%) infertile men. The sperm quality of the cases was further subclassified as normospermia ("Normo," n = 88; 43.56%); teratozoospermia ("T," n = 40; 19.80%); oligoasthenoteratozoospermia ("OAT," n = 37; 18.32%); asthenoteratozoospermia ("AT," n = 19; 9.41%); or oligoteratozoospermia ("OT," n = 18; 8.91%). The assessments of SDF were done using SCD tests. Chromosomal aneuploidy (Chr 13, 18, 21, X, and Y) was investigated using sFISH. Furthermore, based on the fragmentation index, cases were divided into subfertile groups defined as low, medium, high, and severe. The Mann-Whitney test was used to set the upper threshold value for sFISH, and the odds ratio was used for SDF assessment. Results: Cases having sperm quality "AT," "OAT," and "OT" together with the moderate, high, and severe subfertile groups had the highest DNA fragmentation indices: 31.58%, 27.03%, and 22.22%, respectively. In the sFISH analyses, groups with sperm quality "OAT," "T," and "OT" exhibited high degrees of abnormalities: 86.49%, 52.50%, and 50%, respectively. The most common chromosomal abnormalities found were "sex chromosome hyperploidy (XY18)" and "diploid (Chr 13, 21)." The incidences of sperm quality with respect to SDF and sFISH are also reported in detail. Conclusions: This is the first study in the UAE which shows SDF and sFISH incidences together with sperm quality. This study also establishes SDF and sFISH cutoff values for the UAE population.

Reasons that should prompt a referral to a reproductive urologist: guidelines for the gynecologist and reproductive endocrinologist

Obstetricians and gynecologists, and in particular reproductive endocrinologists (REIs), are typically the gatekeepers and first-line providers for couples initially seeking an infertility evaluation. A timely referral to a reproductive urologist may improve pregnancy outcomes in certain clinical scenarios. This review examines the evidence behind circumstances requiring referral and delivers practice-based recommendations on commonly encountered scenarios in the clinic. Scenarios that should prompt referral to a reproductive urologist include semen analysis (SA) abnormalities (e.g., asthenozoospermia, azoospermia, globozoospermia, leukocytospermia, necrozoospermia, oligospermia), recurrent intrauterine insemination (IUI)/in vitro fertilization (IVF) failure, and idiopathic recurrent pregnancy loss (RPL). Conversely, deferment is appropriate in the cases of isolated teratozoospermia and subclinical varicocele. Men with infertility are also at higher risk for other comorbid conditions and should have at least a baseline evaluation by a primary care physician. Coordination of care between a REI and reproductive urologist is critical in several clinical scenarios and expedient referral can improve reproductive outcomes.

Male factor infertility impacts the rate of mosaic blastocysts in cycles of preimplantation genetic testing for aneuploidy

PURPOSE

In this study, we tested the hypothesis that, in PGT-A cycles, decreased semen quality is associated with increased rates of mosaic blastocysts.

METHODS

In a retrospective analysis, three hundred and forty PGT-A cycles are divided into study groups according to semen quality. Cycles were initially divided into two groups, discerning couples with absence of male factor of infertility (non-male factor: NMF; N = 146 cycles) from couples with a male factor of infertility (MF; N = 173 cycles). Couples with severe male factor (SMF) infertility (n = 22) were assessed separately. Embryos were cultured to the blastocyst stage and chromosomally assessed by array comparative genomic hybridization (aCGH). The study did not involve specific interventions.

RESULTS

The reproductive outcome of MF and NMF groups did not indicate statistically significant differences. However, while no differences were found between MF and NMF groups in terms of euploid or aneuploid blastocysts rates, a significantly higher rate of mosaic blastocysts was observed in the MF group (3.6% vs. 0.5%, respectively; P = 0.03). A similar pattern of results was observed in the SMF group when compared with those of the other PGT-A cycles taken together (no SMF). In particular, a significantly higher rate of mosaic blastocysts was observed in the SMF group (7.7% and 1.8%, respectively; P = 0.008).

CONCLUSIONS

The study outcome strongly suggests that compromised semen quality is associated with increased rates of mosaic blastocysts analysed in PGT-A cycles. Sperm assessment appears therefore as an important factor in the determination of embryo development and for a more precise prognostic assessment of PGT-A cases.