Does sperm DNA fragmentation correlate with semen parameters?

Correlation between sperm DNA fragmentation and methylation in male partners of couples with idiopathic recurrent pregnancy loss

With ∼50% recurrent pregnancy loss cases being termed idiopathic (iRPL), understanding of contribution of male factors to iRPL is still lacking. Higher prevalence of sperm DNA fragmentation index (DFI) and lower sperm 5-methylcytosine (5-mC) levels have been previously reported in male partners of iRPL couples and shed light on importance of the male gamete in maintenance of a successful pregnancy. The present study aimed to determine the serum sex steroid hormone levels, sperm DFI and 5-mC and correlation between them in male partners of fertile and iRPL couples. Further, correlation between sperm DFI and 5-mC with semen parameters and paternal age in both groups were determined. 36 male partners of fertile couples and 45 male partners of women experiencing iRPL were enrolled for this study and semen and blood samples were collected. Serum testosterone and estradiol levels were measured by ELISA; sperm DFI and global 5-mC were determined by TUNEL assay and ELISA respectively. Significantly higher serum testosterone levels were noted in the iRPL group (p = 0.028). Incidence of sperm DNA fragmentation was found to be higher in the iRPL study group but with no significance difference. No significant differences in sperm 5-mC values were noted. Upon correlation analysis within both groups, strong significant negative correlation of sperm DFI % and 5-mC % was observed in the control group (p < 0.001) but not the iRPL group (p = 0.249). Hence, we infer that with lower 5-mC levels in sperm genome, there is a higher incidence of sperm DFI in fertile men. However, this trend is not noted in men of iRPL group which could possibly be due to other underlying epigenetic alterations in genomic regions probably unsusceptible to fragmentation. On the other hand, no significant correlations of semen parameters, testosterone, estradiol and paternal age with sperm DFI and 5-mC were noted in both groups.

Correlation between standard sperm parameters and sperm DNA fragmentation from 11,339 samples

Conventional semen parameters have long been considered fundamental in male fertility analyses. However, doubts have been raised regarding the clinical utility of the assessment of spermatozoa (sperm) DNA damage. In this retrospective study, we investigated the potential correlation between conventional semen parameters and semen DNA fragmentation (SDF) assessed as sperm DNA damage, in 11,339 semen samples collected between January 2019 and June 2022. We observed significant negative correlations between the DNA fragmentation index (DFI) and sperm viability (correlation coefficient [r] = -0.514) as well as progressive sperm motility (r = -0.512, p < 0.05). Samples were categorized into three groups according to DFI levels (Groups A, B, and C: ≤15%, 15 < DFI ≤30%, and >30%, respectively). Furthermore, the percentage of semen samples with normal sperm conventional parameters in Groups A, B, and C was 76.7% (4369/5697), 61.4% (2351/3827), and 39.7% (721/1815), respectively. Moreover, according to the reference values of conventional sperm parameters, the samples were divided into Groups F, G, and H with all normal, only one abnormal, and > two abnormal parameters, respectively. In addition, the proportions of samples with abnormal DFI values (>30) in Groups F, G, and H were 9.7% (721/7441), 23.1% (618/2676), and 39.0% (476/1222), respectively. Multivariate logistic regression models demonstrated that sperm vitality, progressive sperm motility, normal sperm form, total sperm count, semen volume, age, and some sperm kinematics collectively improved the area under the receiver operating characteristic curve (AUROC) to 0.861, surpassing the predictive value of a single predictor of pathologically damaged sperm DNA. Our study suggests that samples with abnormal sperm parameters may have a higher likelihood of high DNA fragmentation. Furthermore, certain semen parameters could be potential indicators of sperm DNA fragmentation, aiding sperm selection in assisted reproductive procedures.

Automatic high-throughput and non-invasive selection of sperm at the biochemical level

BACKGROUND

Sperm selection, a key step in assisted reproductive technology (ART), has long been restrained at the preliminary physical level (morphology or motility); however, subsequent fertilization and embryogenesis are complicated biochemical processes. Such an enormous "gap" poses tough problems for couples dealing with infertility, especially patients with severe/total asthenozoospermia .

METHODS

We developed a biochemical-level, automatic-screening/separation, smart droplet-TO-hydrogel chip (BLASTO-chip) for sperm selection. The droplet can sense the pH change caused by sperm's respiration products and then transforms into a hydrogel to be selected out.

FINDINGS

The BLASTO-chip system can select biochemically active sperm with an accuracy of over 90%, and its selection efficiency can be flexibly tuned by nearly 10-fold. All the substances in the system were proven to be biosafe via evaluating mice fertilization and offspring health. Live sperm down to 1% could be enriched by over 76-fold to 76%. For clinical application to patients with severe/total asthenozoospermia, the BLASTO-chip could select live sperm from human semen samples containing 10% live but 100% immotile sperm. The rates of fertilization, cleavage, early embryos, and blastocysts were drastically elevated from 15% to 70.83%, 10% to 62.5%, 5% to 37.5%, and 0% to 16.67%, respectively.

CONCLUSIONS

The BLASTO-chip represents a real biochemical-level technology for sperm selection that is completely independent of sperm's motility. It can be a powerful tool in ART, especially for patients with severe/total asthenozoospermia.

FUNDING

This work was funded by the Ministry of Science and Technology of China, the Ministry of Education of China, and the Shenzhen-Hong Kong Hetao Cooperation Zone.

Exploring the Mechanisms of Yishen Tongluo Decoction on Repairing DNA Damage in Mouse Spermatogonia Cells Based on Whole Transcriptome Sequencing

The aim of this study was to investigate the potential mechanism through which Yishen Tongluo decoction (YSTL) repairs DNA damage caused by benzo(a)pyrene diol epoxide (BPDE) in mouse spermatocytes (GC-2). The GC-2 cells were divided randomly into the control group, BPDE group, and low-, medium-, and high-dose YSTL groups of YSTL decoction. A comet assay was used to detect the DNA fragment index (DFI) of cells in each group. Based on the DFI results, whole transcriptome sequencing was conducted, followed by trend analysis, gene ontology (GO) enrichment analysis, kyoto encyclopedia of genes and genomes (KEGG) enrichment analysis, and ceRNA network analysis. Compared with the control group, the BPDE group reported a significant increase in the DNA fragmentation index (DFI) (p < .05). Compared with the BPDE group, the low-, high- and medium-dose YSTL groups had a significantly reduced DFI (p < .05). Whole-transcriptome sequencing revealed seven differentially expressed circRNAs, 203 differentially expressed miRNAs, and 3,662 differentially expressed mRNAs between the control group and the BPDE group. There was a total of 12 differentially expressed circRNAs, 204 miRNAs, and 2150 mRNAs between the BPDE group and the traditional Chinese medicine group. The pathways involved include DNA repair pathway, nucleotide excision repair pathway, base excision repair pathway, etc. The ceRNA network reported that Hmga2 was the core protein involved, novel_cir_000117 and mmu-miR-466c-3p were located upstream of Hmga2, and they were regulatory factors associated with Hmga2. Finally, we conclude that YSTL decoction may repair sperm DNA damage caused by BPDE through the novel_cir_000117-mmu-miR-466c-3p-Hmga2 pathway.

The Association of Sperm DNA Fragmentation With Serum Lipid Profile Among Males With Abnormal Semen Parameters: An Analytical Cross-Sectional Study

BACKGROUND

Through the ages, infertility, affecting 8% to 12% of couples worldwide, has been a perturbing clinical problem. Approximately 40% to 50% of all infertility cases are due to 'male factor' infertility. Semen analysis is crucial in routinely evaluating idiopathic male infertility. Studies support the idea that semen parameters are associated with serum lipids and sperm DNA fragmentation (SDF). Therefore, it is possible to evaluate male infertility by serum lipid levels, especially before assisted reproduction technology, and modify it by bringing about lifestyle modifications. This study aimed to measure the correlation of SDF with levels of total cholesterol (TC), triglycerides (TG), very low-density lipoprotein (VLDL), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) among males with abnormal semen parameters.

METHODS

A cross-sectional analytical study was conducted in the infertility clinic of a tertiary care hospital. A total of 106 infertile males with abnormal semen analysis as per the WHO criteria (2010) were enrolled in the study. After routine semen analysis, SDF was studied using the comet assay. The serum fasting lipid profile was analyzed using the spectrophotometric kit in the autoanalyzer. The relationship of SDF with serum lipid profile parameters was analyzed.

RESULTS

Out of 106 infertile men, 52% (n = 55) had severe SDF. A modest positive correlation was observed between SDF (percentage of DNA in comet tail) and serum lipid values (serum TG, serum LDL, and serum VLDL).

CONCLUSIONS

Our study is novel in its research on the correlation between SDF and serum lipid values. Based on the findings of our study, it can be concluded that a significant level of SDF was observed in men with high levels of serum TG, LDL, and VLDL. This provokes a potential relationship between sperm DNA integrity and serum lipid profile, which warrants further research.

Tip-microVapour Fast Freezing: A novel easy method for cryopreserving severe oligozoospermic samples

BACKGROUND

Sperm cryopreservation is an important procedure for oligozoospermic subjects at risk of azoospermia and after surgical recovery of spermatozoa in non-obstructive azoospermic men. Conventional procedures for sperm cryopreservation might be, however, not suitable for samples with a very low sperm number.

OBJECTIVES

In this pilot study, we investigated the recoveries of sperm motility and viability in severe oligozoospermic subjects (n = 39) after cryopreservation with a tip-microVapour Fast Freezing, a procedure previously developed by our group for men with good semen quality. Sperm DNA fragmentation was also evaluated in a second group of oligozoospermic samples (n = 16).

MATERIALS AND METHODS

We used a Vapour Fast Freezing procedure using 10 μL tips as carrier, and Test Yolk Buffer as freezing medium (tip-microVapour Fast Freezing). In a subset of samples (n = 22), we compared recovery of motility and viability as obtained with tip-microVapour Fast Freezing and with a Vapour Fast Freezing procedure using 500 μL straws. Sperm DNA fragmentation was evaluated by the sperm chromatin dispersion test.

RESULTS

We found a recovery rate (median [interquartile range]) of 0.29 (0.13-0.41) for progressive motility, 0.30 (0.21-0.52) for total motility and 0.48 (0.29-0.60) for viability. Interestingly, we observed that samples with the poorest motility were apparently less damaged by freezing/thawing. In a subset of samples (n = 22), we directly compared values of viability, progressive motility and total motility by freezing/thawing with tip-microVapour Fast Freezing and Vapour Fast Freezing conducted with 500 μL straws. We found much better values of all sperm parameters in samples after freezing/thawing with tip-microVapour Fast Freezing than with Vapour Fast Freezing in 500 μL straws: that is, progressive motility: 7.00 (3.00-8.50)% versus 2.00 (0.00-4.25)%, p < 0.001; total motility: 12.00 (8.00-16.25)% versus 6.50 (1.00-9.25)%, p < 0.001; viability: 29.75 (23.75-45.25) versus 22.50 (13.75-28.13), p < 0.001, respectively. In the second group of oligozoospermic samples, we found that tip-microVapour Fast Freezing produced lower levels of sperm DNA fragmentation than straws (33.00 [19.75-36.00]% vs. 36.00 [22.75-41.87]%, p < 0.001).

DISCUSSION AND CONCLUSION

Tip-microVapour Fast Freezing appears to be a very promising method to cryopreserve semen samples from severe oligozoospermic patients.

Relationship of environmental exposure temperature and temperature extremes on sperm DNA fragmentation index in men with different BMI values and the indirect effect of DNA fragmentation index on semen parameters

Prior studies have established a significant correlation between the DNA fragmentation index (DFI) and infertility. Additionally, certain investigations suggest that environmental exposure may serve as an etiological factor impacting semen quality. This study aimed to explore the impact of season, ambient temperature, and weather extremes on the DFI of sperm, along with other relevant parameters. Furthermore, it sought to assess how ambient temperature affects the DFI of sperm and other semen parameters in populations with varying BMI values. Additionally, the study analyzed the transient indirect effect of DFI on sperm parameters. This retrospective study analyzed semen samples from 11,877 men, selected based on female factor considerations, spanning from January 2016 to December 2021. Participants were grouped according to the season of semen collection. The results showed that samples collected in summer had a lower semen volume and sperm motility, while those collected in autumn had a lower DFI. We analyzed the exposure-response ratio between environmental exposure temperature and semen parameters using a generalized additive model. Results showed that the curve of the exposure-response relationship was U-shaped or inverted U-shaped; when the air temperature exposure was below the threshold, for each degree of temperature increase, the total sperm motility, sperm concentration, and progressive motility increased by 0.16 %, 0.29 × 10 (Levine, 1999)/ml and 0.14 %, respectively, while the DFI and inactivity rate decreased by 0.078 % and 0.15 %, respectively. When the air temperature exposure exceeded the threshold, for each degree of temperature increase, the sperm concentration, total sperm motility, semen volume and progressive motility decreased by 0.42 × 10 (Levine, 1999)/ml, 0.11 %, 0.0078 ml and 0.15 %, respectively, while the DFI and inactivity rate increased by 0.13 % and 0.12 %, respectively. Extremely cold weather during spermatogenesis was positively correlated with DFI, and extremely hot weather was negatively correlated with sperm motility. Subgroup analysis revealed that individuals classified as overweight / obese exhibited more pronounced changes in sperm parameters and the DFI in response to variations in environmental exposure temperature compared to those with a normal BMI. In the analysis of the relationship between DFI and sperm parameters, the results showed an inverted U-shape relationship between DFI and semen volume, and a negative correlation between DFI and sperm concentration and sperm motility. And we found that ambient temperature affects sperm parameters through DFI at low as well as average temperatures, whereas at high temperatures this indirect effect is no longer present.

A loss-of-function variant in ZCWPW1 causes human male infertility with sperm head defect and high DNA fragmentation

BACKGROUND

Male infertility is a global health issue. The more causative genes related to human male infertility should be further explored. The essential role of Zcwpw1 in male mouse fertility has been established and the role of ZCWPW1 in human reproduction needs further investigation to verify.

METHODS

An infertile man with oligoasthenoteratozoospermia phenotype and his parents were recruited from West China Second University Hospital, Sichuan University. A total of 200 healthy Han Chinese volunteers without any evidence of infertility were recruited as normal controls, while an additional 150 infertile individuals were included to assess the prevalence of ZCWPW1 variants in a sporadic male sterile population. The causative gene variant was identified by Whole-exome sequencing and Sanger sequencing. The phenotype of the oligoasthenoteratozoospermia was determined by Papanicolaou staining, immunofluorescence staining and electron microscope. In-vitro experiments, western blot and in-silicon analysis were applied to assess the pathogenicity of the identified variant. Additionally, we examined the influence of the variant on the DNA fragmentation and DNA repair capability by Sperm Chromatin Dispersion and Neutral Comet Assay.

RESULTS

The proband exhibits a phenotype of oligoasthenoteratozoospermia, his spermatozoa show head defects by semen examination, Papanicolaou staining and electron microscope assays. Whole-exome sequencing and Sanger sequencing found the proband carries a homozygous ZCWPW1 variant (c.1064C > T, p. P355L). Immunofluorescence analysis shows a significant decrease in ZCWPW1 expression in the proband's sperm. By exogenous expression with ZCWPW1 mutant plasmid in vitro, the obvious declined expression of ZCWPW1 with the mutation is validated in HEK293T. After being treated by hydroxyurea, MUT-ZCWPW1 transfected cells and empty vector transfected cells have a higher level of γ-H2AX, increased tail DNA and reduced H3K9ac level than WT-ZCWPW1 transfected cells. Furthermore, the Sperm Chromatin Dispersion assay revealed the proband's spermatozoa have high DNA fragmentation.

CONCLUSIONS

It is the first report that a novel homozygous missense mutation in ZCWPW1 caused human male infertility with sperm head defects and high DNA fragmentation. This finding enriches the gene variant spectrum and etiology of oligoasthenoteratozoospermia.

Gaussian clustering and quantification of the sperm chromatin dispersion test using convolutional neural networks

Sperm DNA fragmentation is a sign of sperm nuclear damage. The sperm chromatin dispersion (SCD) test is a reliable and economical method for the evaluation of DNA fragmentation. However, the cut-off value for differentiation of DNA fragmented sperms is fixed at 1/3 with limited statistical justification, making the SCD test a semi-quantitative method that gives user-dependent results. We construct a collection of deep neural networks to automate the evaluation of bright-field images for SCD tests. The model can detect valid sperm nuclei and their locations from the input images captured with a 20× objective and predict the geometric parameters of the halo ring. We construct an annotated dataset consisting of N = 3120 images. The ResNet 18 based network reaches an average precision (AP50) of 91.3%, a true positive rate of 96.67%, and a true negative rate of 96.72%. The distribution of relative halo radii is fit to the multi-peak Gaussian function (p > 0.99). DNA fragmentation is regarded as those with a relative halo radius 1.6 standard deviations smaller than the mean of a normal cluster. In conclusion, we have established a deep neural network based model for the automation and quantification of the SCD test that is ready for clinical application. The DNA fragmentation index is determined using Gaussian clustering, reflecting the natural distribution of halo geometry and is more tolerable to disturbances and sample conditions, which we believe will greatly improve the clinical significance of the SCD test.

Sperm DNA fragmentation index affect pregnancy outcomes and offspring safety in assisted reproductive technology

The role of sperm DNA fragmentation index (DFI) in investigating fertility, embryonic development, and pregnancy is of academic interest. However, there is ongoing controversy regarding the impact of DFI on pregnancy outcomes and the safety of offspring in the context of Assisted Reproductive Technology (ART). In this study, we conducted an analysis of clinical data obtained from 6330 patients who underwent in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) at the reproductive medical center of The First People's Hospital of Shangqiu and The Affiliated Hospital of Zhengzhou University. The patients was stratified into two distinct groups: IVF group and ICSI group, Within each group, patients were further classified into three subgroups. IVF: group A (< 15%) included 3123 patients, group B (15-30%) included 561 patients, and group C (≥ 30%) included 46 patients. ICSI: group A (< 15%) included 1967 patients, group B (15-30%) included 462 patients, and group C (≥ 30%) included 171 patients. Data were collected and subjected to statistical analysis. There were no significant differences in the basic characteristics among the three groups, and the sperm DFI did not significantly affect the fertilization rates, pregnancy rates, stillbirth rates and the number of birth defects. However, the incidences of miscarriage rates in IVF/ICSI groups with DFI > 30% and DFI 15-30% were significantly higher than those in IVF/ICSI groups with DFI < 15%, and the miscarriage rates in ICSI group with DFI > 30% were significantly higher than DFI 15-30% group, the smooth fitting curve shows that there is a positive correlation between miscarriage rates and sperm DFI (OR 1.095; 95% CI 1.068-1.123; P < 0.001). The birth weight of infants in the IVF/ICSI groups with DFI > 30% and DFI 15-30% exhibited a statistically significant decrease compared to those in the IVF/ICSI groups with DFI < 15%. Furthermore, the birth weight of infants in the ICSI group with DFI > 30% was lower than that of the DFI 15-30% group. The smooth fitting curve analysis demonstrates a negative association between birth weight and sperm DFI (OR 0.913; 95% CI 0.890-0.937; P < 0.001). Sperm DFI has an impact on both miscarriage rates and birth weight in assisted reproductive technology. The smooth fitting curve analysis reveals a positive correlation between miscarriage rates and DFI, while a negative correlation is observed between birth weight and DFI.

Repair mechanism of Yishen Tongluo formula on mouse sperm DNA fragmentation caused by polystyrene microplastics

CONTEXT

Plastics can break down into millions of microplastic (MPs, < 5 mm) particles in the soil and ocean. These MPs can then affect the function of the reproductive system. There is currently no effective solution to this problem aside from traditional Chinese medicine. We have previously used Yishen Tongluo formula (YSTL) to treat sperm DNA damage caused by some toxic substances.

OBJECTIVE

To investigate the mechanism underlying the repair of mouse sperm DNA fragmentation caused by polystyrene microplastics by YSTL.

MATERIALS AND METHODS

An animal model of polystyrene microplastic (PS-MP)-induced sperm DNA damage was replicated by gavage of SPF ICR (CD1) mice PS-MPs at 1 mg/d and treated with YSTL at 11.89, 23.78 and 47.56 g/kg, respectively, for 60 days. The Sperm DNA fragmentation index (DFI) of each group was detected and compared. The target genes of YSTL identified by transcriptomic and proteomic analyses were validated by qRT-PCR and western blotting.

RESULTS

The DFI of the PS group (20.66%) was significantly higher than that of the control group (4.23%). The medium and high doses of the YSTL group (12.8% and 11.31%) exhibited a significant repairing effect. The most enriched pathway was PI3K/Akt. TBL1X, SPARC, hnRNP0, Map7D1, Eps8 and Mrpl27 were screened and SPARC was validated.

DISCUSSION AND CONCLUSIONS

The precise mechanism by which YSTL inhibits PD-MPs DNA damage may be associated with the PI3K/Akt pathway and SPARC. It provides a new direction for using traditional Chinese medicine to prevent and repair reproductive system injury caused by MPs.

Unraveling the Impact of Sperm DNA Fragmentation on Reproductive Outcomes

In recent years, there has been a growing interest in identifying subcellular causes of male infertility, and sperm DNA fragmentation (SDF) research has been at the forefront of this focus. DNA damage can occur during spermatogenesis due to faulty chromatin compaction or excessive abortive apoptosis. It can also happen as sperm transit through the genital tract, often induced by oxidative stress. There are several methods for SDF testing, with the sperm chromatin structure assay, terminal deoxynucleotidyl transferase d-UTI nick end labeling (TUNEL) assay, comet assay, and sperm chromatin dispersion test being the most commonly used. Numerous studies strongly support the negative impact of SDF on male fertility potential. DNA damage has been linked to various morphological and functional sperm abnormalities, ultimately affecting natural conception and assisted reproductive technology outcomes. This evidence-based review aims to explore how SDF influences male reproduction and provide insights into available therapeutic options to minimize its detrimental impact.

Can a sperm selection technique improve embryo ploidy?

BACKGROUND

Spermatozoa with the highest motility retain a superior genomic integrity, and elevated sperm chromatin fragmentation (SCF) has been linked to a lower ability of the conceptus to develop and implant. Therefore, the utilization of a sperm selection method, such as microfluidic sperm selection (MFSS), is capable of reducing the SCF by yielding the most motile fraction of spermatozoa with the highest embryo developmental competence. What remains unclear, however, is the causal mechanism that links SCF to an impaired embryo development.

OBJECTIVES

To identify a relationship between SCF and an unexpectedly high proportion of embryo aneuploidy, while addressing treatment options.

MATERIALS AND METHODS

We identified couples with a high incidence of embryo aneuploidy in a previous intracytoplasmic sperm injection (ICSI) cycle with pre-implantation genetic testing for aneuploidy (PGT-A), utilizing spermatozoa selected by density gradient (DG). Terminal deoxynucleotidyl dUTP transferase nick-end labeling (TUNEL) and neutral Comet assays were carried out on the semen specimens to assess total SCF and double-stranded DNA (dsDNA) fragmentation, respectively. These couples underwent subsequent ICSI/PGT-A cycles with MFSS. Total SCF and dsDNA fragmentation were compared between the two sperm selection methods. Embryo aneuploidy, implantation, clinical pregnancy, delivery, and pregnancy loss rates were compared between the couples' historical DG and subsequent MFSS cycles.

RESULTS

In 57 couples undergoing 71 ICSI/PGT-A cycles, where DG sperm selection was carried out, a high incidence of aneuploid embryos (74.7%) resulted in poor implantation and no viable pregnancies. Testing for SCF, inclusive of dsDNA breaks, evidenced a SCF of 26.2% and dsDNA break of 3.6% in the raw specimen, that decreased to 18.0% (p < 0.001) and 3.1%, respectively, in the DG processed specimen. Following MFSS, total SCF and dsDNA fragmentation decreased to 1.9% and 0.3%, respectively (p < 0.001). The embryo euploidy rate remarkable improved from 25.3% in the DG cycles to 42.9% in the MFSS cycles (p < 0.001). The 6.7% implantation rate in the DG cycles increased to 65.5% in the MFSS cycles (p < 0.001). Similarly, the clinical pregnancy rate rose from 10.5% (DG) to 64.6% (MFSS), resulting in a 62.5% delivery rate (p < 0.001).

DISCUSSION AND CONCLUSIONS

In couples with a relatively young female partner with a negative infertility workup, and a male partner with semen parameters adequate for ICSI, presenting with a high rate of embryo aneuploidy, an additional subtle male factor component may be the culprit. Thus, it is crucial to assess the SCF and test for the dsDNA breaks, which can eventually contribute to embryo chromosomal abnormalities. Given the inverse relationship between SCF and motility, a selection of the most motile gamete by MFSS enhanced the proportion of spermatozoa with an intact genome, contributing to the generation of more euploid embryos that are capable of implanting and yielding increased term pregnancies.

Impact of semen oxidative stress on sperm quality: initial results from Vietnam

OBJECTIVES

This study aimed to determine the relationship between oxidative stress (OS) measured by the oxidation-reduction potential (ORP) and the results of semen analysis among men from infertile couples.

METHODS

This cross-sectional study included 166 men from infertile couples, determined according to the World Health Organization guidelines. The general characteristics, semen analysis, sperm chromatin dispersion assay, and ORP of all subjects were evaluated and analyzed statistically.

RESULTS

Among 166 men from infertile couples, individuals with OS had a significantly higher DNA fragmentation index (DFI) than men without OS (22.37% ± 11.67% vs. 17.98% ± 8.98%). The sperm concentration, total sperm count, motility rate, and normal morphology were negatively correlated, while and an abnormal head and neck-tail were positively correlated with ORP. There was also a positive association between the DFI and OS level. The optimal ORP threshold for determining sperm quality was 0.77 mV/106 sperm/mL (sensitivity, 50.4%; specificity, 93.5%; positive predictive value, 52.9%; negative predictive value, 32.3%).

CONCLUSIONS

Determining the ORP suggests that OS has an adverse effect on the total sperm count, sperm motility, sperm concentration, morphology, vitality, and DNA fragmentation index.

The use of ICSI in ART: evidence for practice

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

Performing a sperm DNA fragmentation test in addition to semen examination based on the WHO criteria can be a more accurate diagnosis of IVF outcomes

BACKGROUND

We analyzed the sperm DNA fragmentation index (DFI) and general semen test based on the World Health Organization (WHO) criteria and compared the two tests using semen factors. In addition, we examined whether DFI is a reliable parameter associated with in vitro fertilization (IVF) outcomes.

METHODS

Sperm chromatin dispersion (SCD) and general semen tests were conducted in accordance with the WHO 2010 guidelines, and correlations between the two tests were investigated. The WHO criteria were set as the cutoff values for each of the following factors: semen volume, concentration, total sperm count, motility, and normal morphology, and compared with the DFI results.

RESULTS

The subjects had a mean sperm DFI of 15.3% ± 12.6%, and the DFI increased with age. In contrast, motility and normal morphology decreased as the DFI increased. Patients who satisfied the WHO criteria in terms of concentration, total sperm count, and motility had a significantly lower DFI than those who did not satisfy the criteria. Therefore, evaluation with a general semen test based on the WHO criteria should be regarded as a qualitative evaluation of all factors other than semen volume and normal morphology.

CONCLUSIONS

High DFI (≥ 30%) caused a low blastocyst development rate following intracytoplasmic sperm injection. Male infertility due to DFI should be suspected when IVF results are poor despite normal semen findings based on the WHO criteria. The results of this study suggest that the SCD test may more accurately evaluate the correlation between IVF clinical outcomes and male infertility. Therefore, it is important to focus on DFI measurements.

How Well Do Semen Analysis Parameters Correlate with Sperm DNA Fragmentation? A Retrospective Study from 2567 Semen Samples Analyzed by the Halosperm Test

Sperm DNA fragmentation (SDF) levels have been measured in the workup for in vitro fertilization (IVF) at PIVET since 2007, with the Halosperm test having replaced the previous sperm chromatin structure assay (SCSA) since 2013. Of 2624 semen samples analyzed for the Halosperm test, 57 were excluded as the sperm concentration was <5 million/mL, a level too low for accurate testing, leaving 2567 samples for assessment within this study. The SDF rates were categorized in 5 sperm DNA fragmentation indices (DFI), ranging from <5% to levels >30%, and these categories were correlated with the respective semen analysis profiles and two clinical parameters, namely the age of the male and the ejaculatory abstinence period prior to the sample. The results showed a significant correlation with male age (r = 0.088; p < 0.0001), the abstinence period (r = 0.076; p = 0.0001), and the semen volume (r 0.063; p = 0.001), meaning an adversely high SDF was associated with advanced age, prolonged abstinence, and raised semen volume parameters. There was a significant negative correlation with sperm morphology (r = −0.074; p = 0.0001), progressive motility (r = −0.257; p < 0.0001), and semen pH (r = −0.066; p < 0.001), meaning these semen anomalies were associated with high SDF values. With respect to abnormal morphology, sperm tail defects had a positive correlation (r = 0.096; p < 0.0001) while midpiece defects showed a negative correlation (r = −0.057; p = 0.004), meaning that tail defects are most likely to associate with adverse DFI values. With respect to motility patterns, the poorer patterns showed a positive correlation with increased DFI, namely C pattern (r = 0.055; p = 0.005) and D pattern (r = 0.253; p < 0.0001). These results imply that raised DFI reflects poor sperm quality and should be investigated in clinical trials involving IVF and the consideration of intracytoplasmic sperm injection (ICSI).

Decrease of air pollution during lockdown in Tuscany (Italy): An effect on sperm DNA fragmentation?

In March 2020, the Italian government imposed a national lockdown which was almost completely removed in June 2020. Due to the abrupt stop of human activities, emissions of air pollutants decreased. Air pollution is an environmental risk factor for noncommunicable disease and mortality. Emerging evidence also suggests a role in male infertility. In this study, we compared sperm DNA fragmentation (sDF) levels and conventional semen parameters between subjects undergoing sDF determination and routine semen analysis in a single Italian centre, during about 6 months before (N = 119) and after lockdown (N = 105). After lockdown, we found an improvement of sperm progressive motility (48.00[38.50-58.00]% vs. 42.00[33.00-53.00]%) and sDF levels (as total: 24.79[18.33-33.97]% vs. 35.02[25.04-45.73]%, p < .001; brighter: 14.02[10.69-17.93]% vs 18.54[13.58-25.82]%, p < .001 and dimmer sDF: 9.24[5.64-15.78]% vs. 12.24[8.08-19.10]%, p < .01), mirrored by a decrease of leukocyte semen concentration (p < .01). The improvement of sperm motility and DNA quality was maintained after adjusting for leukocyte concentration and several conditions known to affect sperm motility and/or sDF levels. With a significant decrease in air pollution observed in Tuscany during and after lockdown, associated improvement in sperm motility and DNA quality in patients referred to the infertility clinic is suggestive of the potential role of air pollution in male infertility.

Intra-individual variation of sperm DNA fragmentation in the Human ejaculate

This retrospective study assessed the biological intra-individual variability of the percentage of sperm with DNA damage (SDF) observed in subsequent ejaculates of the same individual. Variation in SDF was analyzed using the Mean Signed Difference (MSD) statistic based on 131 individuals, comprising 333 ejaculates. Either two, three or four ejaculates were collected from each individual. With this cohort of individuals two main questions were addressed; (1) does the number of ejaculates analyzed influence the variability in the level of SDF associated with each individual? and (2) is the variability observed in SDF similar when individuals are ranked according to their level of SDF? Results showed that the variation observed in mean SDF was not different when 2, 3 or 4 ejaculates were analyzed; consequently, we suggest that the assessment of SDF based on two ejaculates is likely to be representative of the mean SDF expected for the individual. In parallel, it was determined that the variation in SDF increased as SDF increased; in individuals presenting with an SDF value of lower than 30% (potentially fertile), only 5% possessed levels of MSD that could be considered as variable as that presented by individuals presenting with a recurrent high SDF. Finally, we showed that a single assessment of SDF in individuals with medium SDF (20-30%) was less likely to be predictive of the SDF value in the next ejaculate, and therefore, less informative of the patient's SDF status.

Preliminary prediction of semen quality based on modifiable lifestyle factors by using the XGBoost algorithm

Introduction

Semen quality has decreased gradually in recent years, and lifestyle changes are among the primary causes for this issue. Thus far, the specific lifestyle factors affecting semen quality remain to be elucidated.

Materials and methods

In this study, data on the following factors were collected from 5,109 men examined at our reproductive medicine center: 10 lifestyle factors that potentially affect semen quality (smoking status, alcohol consumption, staying up late, sleeplessness, consumption of pungent food, intensity of sports activity, sedentary lifestyle, working in hot conditions, sauna use in the last 3 months, and exposure to radioactivity); general factors including age, abstinence period, and season of semen examination; and comprehensive semen parameters [semen volume, sperm concentration, progressive and total sperm motility, sperm morphology, and DNA fragmentation index (DFI)]. Then, machine learning with the XGBoost algorithm was applied to establish a primary prediction model by using the collected data. Furthermore, the accuracy of the model was verified via multiple logistic regression following k-fold cross-validation analyses.

Results

The results indicated that for semen volume, sperm concentration, progressive and total sperm motility, and DFI, the area under the curve (AUC) values ranged from 0.648 to 0.697, while the AUC for sperm morphology was only 0.506. Among the 13 factors, smoking status was the major factor affecting semen volume, sperm concentration, and progressive and total sperm motility. Age was the most important factor affecting DFI. Logistic combined with cross-validation analysis revealed similar results. Furthermore, it showed that heavy smoking (>20 cigarettes/day) had an overall negative effect on semen volume and sperm concentration and progressive and total sperm motility (OR = 4.69, 6.97, 11.16, and 10.35, respectively), while age of >35 years was associated with increased DFI (OR = 5.47).

Conclusion

The preliminary lifestyle-based model developed for semen quality prediction by using the XGBoost algorithm showed potential for clinical application and further optimization with larger training datasets.

The impact of different WHO reference criteria for semen analysis in clinical practice: who will benefit from the new 2021 thresholds for normal semen parameters?

Background

In 2021, the World Health Organization (WHO) has provided the latest update on processing and evaluating semen analysis.

Objectives

To assess (i) the rate of discordance in semen parameters categorization across three different WHO reference values (namely WHO21, 2010 and 1999) and (ii) the clinical differences among discordant semen analyses from a cohort of primary infertile men.

Materials and methods

Data from 788 infertile men were analyzed. Semen parameters were interpreted based on WHO21, WHO10, and WHO99 reference criteria. Pregnancy outcomes with assisted reproductive techniques (ART) were available for 110 (14%) patients. Descriptive statistics was applied to describe potential differences among the three consecutive WHO references criteria.

Results

Semen parameters categorizations were highly different across the three groups (p < 0.001). Of all, 271 (42.2%) patients had normal semen parameters according to WHO10 but were pathologic when considered with WHO21 reference criteria (namely, men with increased semen abnormalities). Infertile men with increased semen abnormalities had lower testicular volume (p < 0.001) but higher FSH (p < 0.01) and LH (p < 0.001) values than those who had no change in terms of semen parameters categorization. Negative ART outcomes were more frequently reported in men with worsening semen parameters compared with those with confirmed semen parameters at WHO21 versus WHO10 (26.8% vs. 49%, p = 0.03). Conversely, infertile men with worsening semen parameters at WHO21 versus WHO99 were similar in terms of clinical and hormonal characteristics compared with those with the same rate of semen abnormalities.

Conclusions

One out of three infertile men showed worsened semen categorization according to WHO21 versus WHO10. Infertile men with worsening of semen parameters had worse clinical and hormonal characteristics than those with confirmed numbers of semen abnormalities. Moreover, live birth rates were lower in men with worsening semen abnormalities as for WHO21.

Infertility in Men: Advances towards a Comprehensive and Integrative Strategy for Precision Theranostics

Male infertility is an increasing and serious medical concern, though the mechanism remains poorly understood. Impaired male reproductive function affects approximately half of infertile couples worldwide. Multiple factors related to the environment, genetics, age, and comorbidities have been associated with impaired sperm function. Present-day clinicians rely primarily on standard semen analysis to diagnose male reproductive potential and develop treatment strategies. To address sperm quality assessment bias and enhance analysis accuracy, the World Health Organization (WHO) has recommended standardized sperm testing; however, conventional diagnostic and therapeutic options for male infertility, including physical examination and semen standard analysis, remain ineffective in relieving the associated social burden. Instead, assisted reproductive techniques are becoming the primary therapeutic approach. In the post-genomic era, multiomics technologies that deeply interrogate the genome, transcriptome, proteome, and/or the epigenome, even at single-cell level, besides the breakthroughs in robotic surgery, stem cell therapy, and big data, offer promises towards solving semen quality deterioration and male factor infertility. This review highlights the complex etiology of male infertility, especially the roles of lifestyle and environmental factors, and discusses advanced technologies/methodologies used in characterizing its pathophysiology. A comprehensive combination of these innovative approaches in a global and multi-centric setting and fulfilling the suitable ethical consent could ensure optimal reproductive and developmental outcomes. These combinatorial approaches should allow for the development of diagnostic markers, molecular stratification classes, and personalized treatment strategies. Since lifestyle choices and environmental factors influence male fertility, their integration in any comprehensive approach is required for safe, proactive, cost-effective, and noninvasive precision male infertility theranostics that are affordable, accessible, and facilitate couples realizing their procreation dream.

Magnetic-Activated Cell Sorting as a Method to Improve Necrozoospermia-Related Asthenozoospermic Samples

According to some statistics, absolute asthenozoospermia affects every 1 in 5000 men. Although this incidence rate does not appear to be too high, it is extremely important to address the phenomenon because it can drastically reduce the chances of pregnancy, even with assisted reproduction. The biggest problem with absolute asthenozoospermia is that it is difficult to distinguish between live and dead sperm cells, and fertilization with non-viable spermatozoa may contribute to the failure of an assisted reproduction cycle. Nowadays, DNA fragmentation (DF) is a crucial parameter of semen analysis, and in this paper, we provide evidence of the correlation between DF and vitality. For this purpose, the main semen parameters were investigated by a CASA system (concentration, motility, progressive motility, vitality and DF). In the necrozoospermic group (vitality < 58%), all the measured parameters showed significant differences compared to normal vitality. Concentration (30.1 M mL−1 vs. 13.6 M mL−1), motility (31.9% vs. 18.3%), and progressive motility (24.3% vs. 12.7%) were significantly decreased, while DF was significantly increased (17.4% vs. 23.7%). Based on the connection between vitality decrement and DF increment, DF lowering methods, such as magnetic-activated cell sorting, have been hypothesized as novel methods for the elimination of dead spermatozoa.

Microplastics May Be a Significant Cause of Male Infertility

Due to the problematic degradation properties of plastics, the decomposition of plastic results in the formation of numerous microplastics (MPs), less than 5 mm in diameter. These MPs enter the soil and the ocean, eventually passing through the air, water, or food chain back to the human body and harming human health. In the last 80 years, male semen analysis parameters have shown a significant decline for unknown reasons, speculated to be caused by pollutants. No studies examined the relationship between human MP exposure and male infertility. In this article, we reviewed the relevant animal experimental research literature in recent years and calculated that the minimum human equivalent dose of MPs leading to abnormal male semen quality is 0.016 mg/kg/d. The literature comparison found that MP exposure in Japan and South Korea was close to this value. These results suggest that MPs can affect male semen quality and that MPs may significantly impact male fertility.

Correlations between elevated basal sperm DNA fragmentation and the clinical outcomes in women undergoing IUI

OBJECTIVE

This study aimed to explore the impact of the sperm DNA fragmentation index (DFI) on the clinical outcomes in women undergoing artificial insemination by husband intrauterine insemination (AIH-IUI).

METHODS

In this retrospective study, the value of sperm DFI was detected by sperm chromatin structure assay (SCSA) in a semen analysis collected before fertility treatment (basal DFI) in 1,500 IUI cycles at the infertility clinic of Northern Jiangsu People's Hospital Reproductive Medicine Center from Jan 2016 to April 2021. Receiver operating characteristic (ROC) curves were used to calculate the cut-off value for the clinical outcomes of IUI, including the biochemical pregnancy rate, clinical pregnancy rate, delivery rate, and live birth rate, and multivariate logistic regression was conducted to analyse the risk factors for clinical outcomes after IUI.

RESULT

In 1,500 IUI cycles, the results showed that there were no statistically significant differences between the normal DFI group and the abnormal DFI group in biochemical pregnancy rate (14.41% vs. 11.3%, P = 0.386), clinical pregnancy rate (12.9% vs. 10.5%, P = 0.433), delivery rate (11.0% vs. 8.9%, P = 0.456), live birth rate (10.9% vs. 8.9%, P = 0.484) or pregnancy loss rate (14.6% vs. 15.4%, P = 1.000).

CONCLUSION

Sperm DFI alone may have limited predictive power for IUI clinical outcomes.

Studying the mechanism of sperm DNA damage caused by folate deficiency

Sperm DNA injury is one of the common causes of male infertility. Folic acid deficiency would increase the methylation level of the important genes, including those involved in DNA double-strand break (DSB) repair pathway. In the early stages, we analysed the correlation between seminal plasma folic acid concentration and semen parameters in 157 infertility patients and 91 sperm donor volunteers, and found that there was a significant negative correlation between seminal folic acid concentration and sperm DNA Fragmentation Index (DFI; r = -0.495, p < 0.01). Then through reduced representation bisulphite sequencing, global DNA methylation of sperm of patients in the low folic acid group and the high folic acid group was analysed, it was found that the methylation level in Rad54 promoter region increased in the folic acid deficiency group compared with the normal folic acid group. Meanwhile, the results of animal model and spermatocyte line (GC-2) also found that folic acid deficiency can increase the methylation level in Rad54 promoter region, increased sperm DFI in mice, increased the expression of γ-H2AX, that is, DNA injury marker protein, and increased sensitivity of GC-2 to external damage and stimulation. The study indicates that the expression of Rad54 is downregulated by folic acid deficiency via DNA methylation. This may be one of the mechanisms of sperm DNA damage caused by folate deficiency.

Strategies and Perspectives for UV Resonance Raman Applicability in Clinical Analyses of Human Sperm RNA

Developing a deeper knowledge about the impact of DNA and RNA epigenetic mutations on sperm production and fertilization performance is essential for selecting best quality samples in Assisted Reproductive Technologies (ART). Indeed, sperm RNAs adenine and guanine are likely to be methylated in low quality RNA sperm samples and their study requires the employment of techniques able to isolate high quality nucleic acids. UV resonance Raman spectroscopy represents a valuable tool that is able to monitor peculiar molecular modifications occurring predominantly in nucleic acids, being less sensitive to the presence of other biological compounds. In this work, we used an UV Resonance Raman (UVRR) setup coupled to a synchrotron radiation source tuned at 250 nm, in order to enhance sperm RNAs adenine and guanine vibrational signals, reducing also the impact of a fluorescence background typically occurring at lower energies. Despite that our protocol should be further optimized and further analyses are requested, our results support the concept that UVRR can be applied for setting inexpensive tools to be employed for semen quality assessment in ART.

Seminal Plasma Protein N-Glycan Peaks Are Potential Predictors of Semen Pathology and Sperm Chromatin Maturity in Men

Background: Male infertility is increasingly becoming a health and demographic problem. While it may originate from congenital or acquired diseases, it can also result from environmental exposure. Hence, the complexity of involved molecular mechanisms often requires a multiparametric approach. This study aimed to associate semen parameters with sperm DNA fragmentation, chromatin maturity and seminal plasma protein N-glycosylation. Methods: The study was conducted with 166 participants, 20–55 y old, 82 normozoospermic and 84 with pathological diagnosis. Sperm was analyzed by Halosperm assay and aniline blue staining, while seminal plasma total protein N-glycans were analyzed by ultra-high-performance liquid chromatography. Results: Sperm DNA fragmentation was significantly increased in the pathological group and was inversely correlated with sperm motility and viability. Seminal plasma total protein N-glycans were chromatographically separated in 37 individual peaks. The pattern of seminal plasma N-glycan peaks (SPGP) showed that SPGP14 significantly differs between men with normal and pathological semen parameters (p < 0.001). The multivariate analysis showed that when sperm chromatin maturity increases by 10%, SPGP17 decreases by 14% while SPGP25 increases by 25%. Conclusion: DNA integrity and seminal plasma N-glycans are associated with pathological sperm parameters. Specific N-glycans are also associated with sperm chromatin maturity and have a potential in future fertility research and clinical diagnostics.

Flow Cytometry Detection of Sperm DNA Fragmentation and Apoptotic Markers in the Semen of Infertile Males

The effect of sperm molecular defects on fertilization and pregnancy outcome after assisted reproductive therapy (ART) is widely documented by both research and clinical societies. Sperm DNA fragmentation and abnormal chromatin condensation represent critical causes of male infertility. Advanced androgenic techniques for accurately identifying molecular defects help in selecting an appropriate treatment strategy. Additionally, specific markers of apoptosis are increasingly important in predicting male infertility. The ability of flow cytometry to estimate the quantity of sperm with DNA fragmentation or damage and multifactor measurements in immotile sperm have made this developed technique essential in fertility centers. The study is aimed at assessing the level of DNA fragmentation and apoptosis by measuring flow cytometry using new techniques. Flow cytometry analysis revealed a varying degree of DNA damage. It was able to quantify the degree of impairment even in samples with minimal DNA fragmentation. DNA damage was observed even in samples that were considered normal with a routine semen analysis. Flow cytometry was sensitive to changes in sperm apoptosis. Elevated p53 activity levels were associated with high DNA fragmentation. Meanwhile, B-cell lymphoma 2 (Bcl-2) activities showed a different pattern. In conclusion, flow cytometry for sperm DNA fragmentation and markers of apoptosis can be a valuable tool in assisted reproductive centers.

A Modified Flotation Density Gradient Centrifugation Technique Improves the Semen Quality of Stallions with a High DNA Fragmentation Index

Sperm DNA fragmentation compromises fertilization and early embryo development. Since spermatozoa lack the machinery to repair DNA damage, to improve the likelihood of establishing a healthy pregnancy, it is preferable to process ejaculates of stallions with a high sperm DNA fragmentation index (DFI) before artificial insemination or intracytoplasmic sperm injection. The aim of this study was to examine a modified flotation density gradient centrifugation (DGC) technique in which semen was diluted with a colloid solution (Opti-prepTM) to increase its density prior to layering between colloid layers of lower and higher density. The optimal Opti-prepTM solution (20-60%) for use as the bottom/cushion layer was first determined, followed by a comparison between a modified sedimentation DGC and the modified flotation DGC technique, using different Opti-prepTM solutions (20%, 25% and 30%) as the top layer. Finally, the most efficient DGC technique was selected to process ejaculates from Friesian stallions (n = 3) with high sperm DFI (>20%). The optimal Opti-prepTM solution for the cushion layer was 40%. The modified sedimentation technique resulted in two different sperm populations, whereas the modified flotation technique yielded three populations. Among the variants tested, the modified flotation DGC using 20% Opti-prepTM as the top layer yielded the best results; the average sperm recovery was 57%; the DFI decreased significantly (from 12% to 4%) and the other sperm quality parameters, including progressive and total motility, percentages of spermatozoa with normal morphology and viable spermatozoa with an intact acrosome, all increased (p < 0.05). In Friesian stallions with high sperm DFI, the modified flotation DGC markedly decreased the DFI (from 31% to 5%) and significantly improved the other semen quality parameters, although sperm recovery was low (approximately 20%). In conclusion, stallion sperm DFI and other sperm quality parameters can be markedly improved using a modified flotation DGC technique employing a 40% Opti-prepTM cushion and a 20% top layer.

Environmental and occupational exposures associated with male infertility

The upsurge in male infertility over the last two decades, possibly due to environmental exposure, has raised significant interest, particularly boosted by reports from fertility clinics, which showed that chronic diseases and hereditary or other medical conditions might only partially explain current incidence of male infertility. Both environmental and occupational settings may have a significant role in exposure to complex mixtures of endocrine disruptors (ED), which play a major role in fertility disorders. The aim of this review is to give an insight into the current knowledge on exposure settings which may be associated with male infertility. Our study relied on a systematic search of PubMed, Scopus, and Web of Science for articles published between January 2000 and September 2020. It showed that some well documented factors associated with male infertility include smoking, and physiological disturbances or chronic diseases such as obesity and diabetes, which in turn, may also reflect lifestyle choices and environmental exposures, especially to EDs such as phthalates, bisphenols, pesticides, and flame retardants. However, the number of studies on the aetiology of male infertility is still too low in comparison with the size of affected population. Occupational health follow-ups and medical surveillance do not collect any data on male infertility, even though ED chemicals are part of many technological processes.

Correlation among isolated teratozoospermia, sperm DNA fragmentation and markers of systemic inflammation in primary infertile men

Aim

To assess the prevalence of isolated teratozoospermia (iTZS) in a cohort of infertile and fertile men; explore the relationship between iTZS, inflammatory parameters and sperm DNA fragmentation index (SDF) in the same cohort.

Materials and methods

1824 infertile men and 103 fertile controls. Semen analysis, the neutrophil-to-lymphocyte ratio (NLR) and serum hormones were investigated. DFI was tested in infertile men only. According to 2010 WHO semen analysis, patients were categorized in 3 sub-groups of isolated sperm defects: isolated oligozoospermia (iOZS), isolated asthenozoospermia (iAZS) and iTZS. Descriptive statistics and linear regression models tested the association between clinical variables and inflammatory markers.

Results

Among infertile men, iAZS, iTZS, and iOZS were found in 13.9%, 11.9% and 4.1% participants, respectively. iTZS was found in 37 (35.9%) fertile men. Infertile men with iTZS had higher NLR values than those with iOZS, iAZS and men with normal semen parameters (all p<0.001). FSH and LH were higher and inhibin B lower in iOZS infertile men compared to all other groups (p≤0.001). Hormonal characteristics were similar between iTZS infertile and fertile men. Similarly, iTZS infertile men had higher SDF than all other groups (all p<0.001). Infertile men with iTZS had higher NLR values than fertile men with iTZS (p<0.01). Linear regression analysis showed that, in infertile men, iTZS was associated with SDF and NLR (all p≤0.01).

Conclusions

iTZS was found in 11.9% of infertile men but it was even more prevalent in fertile controls. Infertile men with iTZS had higher NLR than fertile controls and increased SDF values than infertile participant with iAZS, iOZS, or normal semen parameters. No differences in hormonal characteristics were found between infertile and fertile men with iTZS.

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

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

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.

Age-related changes in human conventional semen parameters and sperm chromatin structure assay-defined sperm DNA/chromatin integrity

RESEARCH QUESTION

What are the correlations between male age, traditional semen parameters, sperm DNA fragmentation index (DFI) and high DNA stainability (HDS) in a sufficiently large sample size?

DESIGN

Retrospective cohort study of 18,441 semen samples, with data divided into seven age groups according to male age: ≤25, 26-30, 31-35, 36-40, 41-45, 46-50 and ≥51 years.

RESULTS

Age was negatively correlated with semen volume, total sperm count, motility and HDS, and positively correlated with sperm concentration and DFI (P < 0.001). After 35 years of age, semen volume and total sperm count began to decline. After 30 years of age, motility and HDS decreased consistently. Sperm concentration and DFI increased from 26-30 years of age. DFI was negatively correlated with sperm concentration, total sperm count, motility and normal morphology (P < 0.001) and positively correlated with semen volume and HDS (P < 0.001). HDS was negatively correlated with all parameters (P < 0.001) except semen volume (r = -0.013, P = 0.074) and DFI (r = 0.124, P < 0.001). Patients aged ≥40 years had higher DFI than those aged <40 years in the entire cohort, in the abnormal semen parameters cohort, and in the normal semen parameters cohort (OR 2.145, 2.042, 1.948, respectively, P < 0.001). The ≥40 years age group had a lower HDS than the <40 years age group in the entire cohort and abnormal semen parameters cohort (OR 0.719, 0.677, respectively, P < 0.001).

CONCLUSIONS

Ageing is a negative effector of sperm quantity and quality, and routine sperm parameters have weak but significant correlations with sperm DNA/chromatin integrity.

The Prevalence and Components of Metabolic Syndrome in Men from Infertile Couples and Its Relation on Semen Analysis

PURPOSE

Metabolic syndrome (MetS) has been reported as a deleterious factor in male fertility potential, associated with hypogonadism, impaired spermatogenesis, decreased sperm concentration and motility, and increased sperm DNA damage. This study aimed to determine the prevalence of MetS in men from infertile couples and evaluate its effect on semen analysis (SA).

PARTICIPANTS AND METHODS

A cross-sectional descriptive study was performed in men from infertile couples diagnosed based on the World Health Organization 2010 criteria and treated at the Hue Center for Reproductive Endocrinology and Infertility, Vietnam. General information included medical history, lifestyle, MetS factors, SA, and sperm DNA fragmentation test were collected. Based on the diagnostic criteria of the American Heart Association and the National Heart, Lung, and Blood Institute for Asian men, the study population was divided into two groups: MetS and non-MetS groups. The outcomes were analyzed for any relationship between MetS and the SA index and the DNA fragmentation index (DFI).

RESULTS

A total of 534 men from infertile couples were included in this study. The prevalence of MetS was 23.4%, and abnormal semen analysis accounted for 93.8%. Age, body mass index (BMI), waist-to-hip ratio (WHR), waist-to-height ratio (WHtR), hepatitis B and total cholesterol were related to the occurrence of MetS in infertile men (p <0.05). MetS did not reveal any impact on the parameters of SA. There was a positive correlation between waist circumference (WC), WHR, WHtR, and systolic blood pressure (BP) with abnormal sperm head and DFI (p <0.05).

CONCLUSION

Although the prevalence of MetS was remarkable in men from infertile couples, there was no association between MetS and semen quality. However, WC, WHR, WHtR, and systolic BP were found to be significantly associated with abnormal sperm head and DFI.

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.

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.

Predictive factors for intrauterine insemination outcomes: a review

PURPOSE

Intrauterine insemination (IUI) is a frequently utilized method of assisted reproduction for patients with mild male factor infertility, anovulation, endometriosis, and unexplained infertility. The purpose of this review is to discuss factors that affect IUI outcomes, including infertility diagnosis, semen parameters, and stimulation regimens.

METHODS

We reviewed the published literature to evaluate how patient and cycle specific factors affect IUI outcomes, specifically clinical pregnancy rate, live birth rate, spontaneous abortion rate and multiple pregnancy rate.

RESULTS

Most data support IUI for men with a total motile count > 5 million and post-wash sperm count > 1 million. High sperm DNA fragmentation does not consistently affect pregnancy rates in IUI cycles. Advancing maternal and paternal age negatively impact pregnancy rates. Paternal obesity contributes to infertility while elevated maternal BMI increases medication requirements without impacting pregnancy outcomes. For ovulation induction, letrozole and clomiphene citrate result in similar pregnancy outcomes and are recommended over gonadotropins given increased risk for multiple pregnancies with gonadotropins. Letrozole is preferred for obese women with polycystic ovary syndrome. IUI is most effective for women with ovulatory dysfunction and unexplained infertility, and least effective for women with tubal factor and stage III-IV endometriosis. Outcomes are similar when IUI is performed with ovulation trigger or spontaneous ovulatory surge, and ovulation may be monitored by urine or serum. Most pregnancies occur within the first four IUI cycles, after which in vitro fertilization should be considered.

CONCLUSIONS

Providers recommending IUI for treatment of infertility should take into account all of these factors when evaluating patients and making treatment recommendations.

Sperm DNA fragmentation testing: Summary evidence and clinical practice recommendations

We herein summarise the evidence concerning the impact of sperm DNA fragmentation in various clinical infertility scenarios and the advances on sperm DNA fragmentation tests. The collected evidence was used to formulate 41 recommendations. Of these, 13 recommendations concern technical aspects of sperm DNA fragmentation testing, including pre‐analytical information, clinical thresholds and interpretation of results. The remaining 28 recommendations relate to indications for sperm DNA fragmentation testing and clinical management. Clinical scenarios like varicocele, unexplained infertility, idiopathic infertility, recurrent pregnancy loss, intrauterine insemination, in vitro fertilisation/intracytoplasmic sperm injection, fertility counselling for men with infertility risk factors and sperm cryopreservation have been contemplated. The bulk evidence supporting the recommendations has increased in recent years, but it is still of moderate to low quality. This guideline provides clinicians with advice on best practices in sperm DNA fragmentation testing. Also, recommendations are provided on possible management strategies to overcome infertility related to sperm DNA fragmentation, based on the best available evidence. Lastly, we identified gaps in knowledge and opportunities for research and elaborated a list of recommendations to stimulate further investigation.

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.

Diagnostic value of advanced semen analysis in evaluation of male infertility

Conventional semen analysis is the standard of care to initially evaluate the fertility status of a male patient. However, it has some limitations and among these are failure to correctly identify the aetiology underlying fertility problems, intra- and inter-observer variability and incomplete information about sperm function. Considering these drawbacks, advanced semen tests have been developed to assess male infertility, including sperm function tests, oxidative stress (OS) and sperm DNA fragmentation (SDF) tests. This review illustrates the commonly utilised sperm function techniques, along with the assays used to assess SDF and OS and their diagnostic value.

DNA fragmentation index (DFI) as a measure of sperm quality and fertility in mice

Although thousands of genetically modified mouse strains have been cryopreserved by sperm freezing, the likelihood of cryorecovery success cannot be accurately predicted using conventional sperm parameters. The objective of the present study was to assess the extent to which measurement of a sperm DNA fragmentation index (DFI) can predict sperm quality and fertility after cryopreservation. Using a modified TUNEL assay, we measured and correlated the DFI of frozen-thawed sperm from 83 unique mutant mouse strains with sperm count, motility and morphology. We observed a linear inverse correlation between sperm DFI and sperm morphology and motility. Further, sperm DFI was significantly higher from males with low sperm counts compared to males with normal sperm counts (P < 0.0001). Additionally, we found that viable embryos derived using sperm from males with high DFI (62.7 ± 7.2% for IVF and 73.3 ± 8.1% for ICSI) failed to litter after embryo transfer compared to embryos from males with low DFI (20.4 ± 7.9% for IVF and 28.1 ± 10.7 for ICSI). This study reveals that measurement of DFI provides a simple, informative and reliable measure of sperm quality and can accurately predict male mouse fertility.